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TUGAS AKHIR (608502A)

PENGARUH HIBRID RESIN DENGAN VARIASI

SUSUNAN MAT DAN WOVEN ROVING

TERHADAP KETAHANAN KOROSI PADA FLUIDA

ASAM PHOSPAT DAN KEKUATAN TARIK

Ibnu Abdil Aziz NRP. 0815040022

Dosen Pembimbing : BUDI PRASOJO, S.T., M.T. IR MM. EKO PRAYITNO, M.MT

PROGRAM STUDI TEKNIK PERPIPAAN

JURUSAN TEKNIK PERMESINAN KAPAL

POLITEKNIK PERKAPALAN NEGERI SURABAYA

SURABAYA

2019

i

TUGAS AKHIR (608502A)

PENGARUH HIBRID RESIN DENGAN VARIASI

SUSUNAN MAT DAN WOVEN ROVING TERHADAP

KETAHANAN KOROSI PADA FLUIDA ASAM

PHOSPAT DAN KEKUATAN TARIK

Ibnu Abdil Aziz NRP. 0815040022

Dosen Pembimbing : BUDI PRASOJO,S.T.,M.T. Ir. M. M. EKO PRAYITNO, M.MT

PROGRAM STUDI TEKNIK PERPIPAAN

JURUSAN TEKNIK PERMESINAN KAPAL


SURABAYA

2019

iii

LEMBAR PENGESAHAN TUGAS AKHIR

PENGARUH HIBRID RESIN DENGAN VARIASI SUSUNAN MAT DAN

WOVEN ROVING TERHADAP KETAHANAN KOROSI PADA FLUIDA

ASAM PHOSPAT DAN KEKUATAN TARIK

Disusun Oleh:

Ibnu Abdil Aziz

0815040022

Diajukan Untuk Memenuhi Salah Satu Syarat Kelulusan

Program Studi D4 Teknik Perpipaan

Jurusan Teknik Permesinan Kapal


Disetujui oleh Tim penguji Tugas Akhir Tanggal Ujian : 24 Juli 2019

Periode Wisuda : September 2019

Menyetujui,

Dosen Penguji NIDN Tanda Tangan

v

PERNYATAAN BEBAS PLAGIAT

No. : F.WD I. 021

Date : 3 Nopember 2015

Rev. : 01

Page : 1 dari 1

Yang bertanda tangan di bawah ini:

Nama : Ibnu Abdil Aziz

NRP : 0814040022

Jurusan/Prodi : Teknik Permesinan Kapal/Teknik Perpipaan

Dengan ini menyatakan sesungguhnya bahwa:

Tugas Akhir yang saya kerjakan dengan judul :

“PENGARUH HIBRID RESIN DENGAN VARIASI SUSUNAN MAT DAN

WOVEN ROVING TERHADAP KETAHANAN KOROSI PADA FLUIDA

ASAM PHOSPAT DAN KEKUATAN TARIK”

Adalah Benar karya saya sendiri dan bukan plagiat dari karya orang lain.

Apabila dikemudian hari terbukti terdapat plagiat dalam karya ilmiah tersebut,

maka saya bersedia menerima sanksi sesuai ketentuan peraturan yang berlaku.

Demikian surat pernyataan ini saya buat dengan penuh tanggung jawab.

Surabaya, 17 Juli 2019

Yang membuat pernyataan,

(Ibu Abdil Aziz)

NRP. 0815040022

vii

KATA PENGANTAR

Puji syukur penulis panjatkan kepada Allah SWT atas segala rahmat, ridho,

dan hidayah-Nya penulis dapat menyelesaikan penyusunan Tugas Akhir ini dengan

baik dan lancar. Penulis juga mengucapkan shalawat serta salam semoga senantiasa

terlimpah curahkan kepada Nabi Muhammad SAW, kepada keluarganya, dan para

sahabat yang telah memberikan teladan bagi seluruh umat manusia.

Tugas akhir yang berjudul “PENGARUH HIBRID RESIN DENGAN

VARIASI SUSUNAN MAT DAN WOVEN ROVING TERHADAP

KETAHANAN KOROSI PADA FLUIDA ASAM PHOSPAT DAN KEKUATAN

TARIK” ini disusun sebagai salah satu persyaratan untuk menyelesaikan

pendidikan kuliah di Program Studi D-IV Teknik Perpipaan. Penulis menyadari

penyelesaian dan penyusunan Tugas Akhir ini tidak terlepas dari kerjasama,

bantuan, dan bimbingan dari berbagai pihak, sehingga penulis menyampaikan

terimakasih yang sebesar-besarnya kepada :

1. Bapak Ir. Eko Julianto, M.Sc, FRINA., selaku Direktur Politeknik Perkapalan

Negeri Surabaya.

2. Bapak George Endri K, S.T., M.Sc.Eng., sebagai Ketua Jurusan Teknik

Permesinan Kapal, Politeknik Perkapalan Negeri Surabaya.

3. Bapak R. Dimas Endro Witjonarko, S.T., M.T., sebagai Ketua Program Studi

Teknik Perpipaan, Politeknik Perkapalan Negeri Surabaya.

4. Bapak Budi Prasojo S.T., M.T., sebagai dosen pembimbing I yang telah

memberikan banyak bimbingan dan pengarahan selama pengerjaan tugas akhir.

5. Bapak Ir MM. Eko Prayitno, M.MT sebagai dosen pembimbing II yang telah

memberikan banyak bimbingan dan pengarahan selama pengerjaan tugas akhir.

6. Kedua orang tua yang telah memberikan banyak kasih sayang, nasehat hidup,

doa, dukungan moril serta materil, dan segalanya bagi penulis.

7. Pembimbing PT. Petro Jordan Abadi Gresik : Bapak Shochib, Mas Rizal, Mas

Fajar, Mas Angola, dan karyawan-karyawan lainnya yang namanya tidak bisa

disebutkan satu persatu.

viii

8. Staf pengajar Program Studi Teknik Perpipaan yang telah memberikan banyak

ilmu kepada penulis selama masa perkuliahan.

9. Teman-teman Teknik Perpipaan angkatan 2015 yang telah memberikan

motivasi kepada penulis.

10. Semua pihak yang tidak dapat disebutkan satu-satu. Penulis menyadari bahwa

Tugas Akhir ini masih jauh dari kesempurnaan. Harapan penulis dapat

mendapatkan kritik atau saran yang membangun agar penelitian yang telah

dilakukan menjadi lebih baik lagi. Semoga Tugas Akhir ini bermanfaat bagi

pembaca

Penulis menyadari bahwa dalam penyusunan Tugas Akhir ini masih banyak

kekurangan. Oleh karena itu, saran dan kritik yang membangun sangat penyusun

harapkan guna penyempurnaan Tugas Akhir ini, sehingga dapat bermanfaat bagi

pembacanya.

Surabaya,17 Juli 2019

Ibnu Abdil Aziz

ix

PENGARUH HIBRID RESIN DENGAN VARIASI SUSUNAN

MAT DAN WOVEN ROVING TERHADAP KETAHANAN

KOROSI SERTA KEKUATAN TARIK PADA FLUIDA ASAM

PHOSPAT

Ibnu Abdil Aziz

ABSTRAK

Pada pabrik bahan kimia sering terjadi permasalahan korosi yang

disebabkab oleh keasaman fluida. Seperti instalasi pada plant asam phospat di salah

satu pabrik daerah Manyar Roomo Gresik yang memiliki tingkat keasaman cukup

tinggi. Untuk mengatasi hal ini instalasi pada plant menggunakan material berupa

Fiberglass Reinforced Plastics yang kuat dan tahan terhadap korosi. Material

tersebut terbuat dari susunan layer woven roving dan mat yang dilaminasi

menggunakan resin, katalis, dan bahan tambahan lainya.Pada tugas akhir ini akan

dibahas mengenai pengujian material Fiberglass Reinforced Plastics dengan

variasi komposisi hibrid derakane 411-157 BQTN EX serta susunan Mat dan WR.

Pada pengujian tersebut terdapat pengujian Immersion test dan Tensile test untuk

mengetahui ketahanan korosi dan kekuatan materilannya. Pengujian pada material

dilakukan dengan menggunakan 36 sample spesimen yang terdiri dari 3 jenis

komposisi hibrid resin dan 3 jenis susunan Mat dan WR. Proses Uji tarik mengacu

pada ASTM D-638 ”Standart Test Method for Tensile Properties of Plastics”

sedangkan Immersion Test mengacu pada ASTM-G31. Dari penelitian di atas

didapatkan nilai corrosion rate tertinggi dan nilai kekuatan tarik terendah dari

spesimen FRP hibrid resin (50% DERAKANE 411 50% 157 BQTN EX) dengan

variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 0,01641 mm/year dan 123,95 MPa.

Dapat disimpulkan spesimen yang memiliki kekuatan tarik terbesar dan tahan

korosi terhadap fluida asam phospat dengan pH1 dan temperature 70° yaitu

spesimen yang memiliki persentase resin DERAKANE 411 tinggi dan jumlah

woven roving yang banyak pada susunan layer.

. Kata Kunci: Fiberglass Reinforced Plastics, Hybrid resin, Immersion test, and Tensile test

xi

THE INFLUENCE OF HYBRID RESIN WITH VARIATION OF

MATS AND WOVEN ROVING AGAINST CORROSION

RESISTENCE IN PHOSPHATE ACID FLUIDS AND TENSILE

STRENGTH

Ibnu Abdil Aziz

ABSTRACT

In chemical plants, corrosion problems often occur due to fluid acidity. Such as the

installation of a phosphoric acid plant in one of the Manyar Roomo Gresik area factories which has

a fairly high acidity level. To overcome this, the plant installation uses materials such as Fiberglass

Reinforced Plastics which are strong and resistant to corrosion. The material is made from a layer

of woven roving and mat laminated using resin, catalysts and other additives. In this final project,

we will examine Fiberglass Reinforced Plastics material with a variety of hybrid compositions from

411-157 BQTN EX and Mat and WR arrangements. In this test there is a test of Immersion test and

Tensile test to determine the corrosion resistance and material strength. Tests on materials were

carried out using 36 specimen samples consisting of 3 types of resin hybrid compositions and 3

types of Mat and WR arrangements. The tensile test process refers to ASTM D-638 "Standard Test

Method for Tensile Properties of Plastics" while the Immersion Test refers to ASTM-G31. From the

above research the highest corrosion rate and the lowest tensile strength value of FRP hybrid resin

specimens (50% DERAKANE 411 50% 157 BQTN EX) with layer 1 variations (w, m, m, w, m, m,

m, w) ) which is 0.01641 mm / year and 123.95 MPa. It can be concluded that specimens that have

the greatest tensile strength and are corrosion resistant to phosphoric acid fluids with pH1 and

temperature70 ° are specimens that have a high percentage of DERAKANE 411 resin and a large

amount of woven roving on the layer arrangement.

Keyword: Fiberglass Reinforced Plastics, Hybrid resin, Immersion test, and Tensile test

xiii

DAFTAR ISI

LEMBAR PENGESAHAN ................................................................................... iii

PERNYATAAN BEBAS PLAGIAT ....................................................................... v

KATA PENGANTAR .......................................................................................... vii

ABSTRAK ............................................................................................................. ix

ABSTRACT ........................................................................................................... xi

DAFTAR ISI ........................................................................................................ xiii

DAFTAR GAMBAR ............................................................................................. xv

DAFTAR TABEL ............................................................................................... xvii

DAFTAR SIMBOL .............................................................................................. xix

BAB 1 PENDAHULUAN ...................................................................................... 1

1.1 Latar Belakang .............................................................................................. 1

1.2 Rumusan Masalah ......................................................................................... 2

1.3 Tujuan Penelitian .......................................................................................... 3

1.4 Manfaat Penelitian ........................................................................................ 3

1.5 Batasan Masalah............................................................................................ 3

BAB 2 TINJAUAN PUSTAKA ............................................................................. 5

2.1 Klasifikasi Material Pipa ............................................................................... 5

2.2 Fluida dan Karakteristiknya .......................................................................... 6

2.2.1 Karakteristik dan sifat fluida ......................................................................... 7

2.3 FRP (Fiberglass Reinforced Plastics) ......................................................... 11

2.3.1 Bahan-bahan pembuat Fiberglass Reinfoorced Plastics ............................ 11

2.3.2 Bahan-bahan pendukung Fiberglass Reinfoorced Plastics ........................ 15

2.3.3 Peralatan Fiberglass Reinfoorced Plastics.................................................. 16

2.4 Penentuan Ketebalan ................................................................................... 16

2.5 Proses Pembuatan ....................................................................................... 17

2.6 Pengujian Immersion Test System .............................................................. 22

2.6.1 Metode Weight Loss (Kehilangan Berat) .................................................... 22

2.7 Kekuatan Tarik ........................................................................................... 23

2.7.1 Kekuatan luluh (yield strength) ................................................................... 27

xiv

2.7.2 Modulus elastisitas ..................................................................................... 28

2.7.2 Pengukuran keliatan dan keuletan .............................................................. 28

2.7.3 Dimensi Spesimen Benda Uji .................................................................... 29

2.8 Kerangka Konseptual ................................................................................ 29

BAB 3 METODOLOGI PENELITIAN ............................................................... 31

3.1 Diagram Alir ............................................................................................... 31

3.2 Langkah penelitian ..................................................................................... 32

3.2.1 Tahap Identifikasi Awal ............................................................................. 32

3.2.2 Tahap Pengumpulan Data ........................................................................... 33

3.2.3 Tahap Laminasi dan Pengolahan Data ....................................................... 33

3.2.4 Tahap Analisa dan Kesimpulan .................................................................. 37

3.3 Bahan dan Alat Pengujian .......................................................................... 37

3.4 Waktu dan Tempat Penelitian .................................................................... 38

BAB 4 ANALISA DAN PENGOLAHAN DATA .............................................. 41

4.1 Data Penelitian ............................................................................................ 41

4.1.1 Data Fluida ................................................................................................. 41

4.1.2 Data Material .............................................................................................. 42

4.2 Perhitungan Luas Area yang Terpapar ............................................................ 42

4.3 Perhitungan Kecepatan ............................................................................... 44

4.4 Uji ImmersionTest ...................................................................................... 44

4.5 Analisa Perhitungan Corrosion Rate FRP .................................................. 46

4.6 Analisa Kekuatan Tarik FRP ...................................................................... 49

4.3.3 Analisa Variasi Optimum ........................................................................... 52

BAB 5 KESIMPULAN DAN SARAN ................................................................ 55

5.1 Kesimpulan ................................................................................................. 55

5.2 Saran ........................................................................................................... 56

DAFTAR PUSTAKA ............................................................................................ 57

LAMPIRAN .......................................................................................................... 59

xv

DAFTAR GAMBAR

Gambar 2. 1 Grafik Rheogram fluida Newtonian dan non-Newtonian ................... 7

Gambar 2. 2 Wax (Google, 2018) ......................................................................... 12

Gambar 2. 3 Matt (Google, 2018) ......................................................................... 12

Gambar 2. 4 Polyesters Resin (Google, 2018) ...................................................... 13

Gambar 2. 5 Polyesters (Isophathalic) .................................................................. 13

Gambar 2. 6 Epoxy Resin ..................................................................................... 14

Gambar 2. 7Vinyl Ester......................................................................................... 14

Gambar 2. 8 Katalis (Google, 2018) ..................................................................... 14

Gambar 2. 9Woven Roving (Google, 2018) ......................................................... 15

Gambar 2. 10 MT 200 .......................................................................................... 17

Gambar 2. 11 Metode hand lay-up ....................................................................... 18

Gambar 2. 12 Metode Filament Winding .............................................................. 19

Gambar 2. 13 Metode Spray Up ........................................................................... 20

Gambar 2. 14 Metode Pultrusion .......................................................................... 21

Gambar 2. 15 Alat Resin Transfer Molding (RTM) ............................................. 21

Gambar 2. 16 Pengukuran dimensi benda uji (ASTM, 2003)............................... 29

Gambar 2. 17 Tabel Detail dimensi spesimen benda uji (ASTM, 2003) .............. 29

Gambar 3. 1 Diagram Alir .................................................................................... 31

Gambar 3. 2 Variasi susunan WR dan Mat 100% Derakane 411 ......................... 35

Gambar 3. 3 Variasi susunan WR dan Mat 75% Derakane 411 25% 157 ........... 35

Gambar 3. 4 Variasi susunan WR dan Mat 50% Derakane 411 50% 157 BQTN

EX ......................................................................................................................... 35

Gambar 3. 5 Dimensi Spesimen ............................................................................ 36

Gambar 3. 6 Skema Alat ....................................................................................... 38

Gambar 4. 1 Grafik Pengaruh hibrid resin dengan variasi susunan mat dan woven

roving terhadap ketahan korosi ............................................................................ 48

xvi

Gambar 4. 2 Grafik Pengaruh hibrid resin dengan variasi susunan mat dan woven

roving terhadap kekuatan tarik FRP ...................................................................... 51

Gambar 4. 3 Grafik Analisa Variasi Optimum ...................................................... 53

xvii

DAFTAR TABEL

Tabel 2.1 Standart laminate coposition ................................................................ 16

Tabel 3. 1 Gambar dan Rumus Perhitungan Luas Permukaan.............................. 36

Tabel 3. 2 Ukuran dimensi spesimen pengujian tarik ........................................... 37

Tabel 3. 3 Jadwal Penelitian.................................................................................. 39

Tabel 4. 1 Data Fluida Asam Phospat ................................................................... 41

Tabel 4. 2 Data Material FRP ............................................................................... 42

Tabel 4. 3 Luas Area Total .................................................................................... 43

Tabel 4. 4 Pengurangan Berat Spesimen FRP ...................................................... 45

Tabel 4. 5 Corrosion Rate FRP ............................................................................. 46

Tabel 4. 6 Kekuatan Tarik FRP............................................................................. 49

xix

DAFTAR SIMBOL

PD = Design pressure [MPa]

Td = Design temperature [oC]

To = Operational temperature [oC]

Q = Debit [m3/s]

ρm = Density mixture [kg/m3]

dp = Diameter pasir [m]

ṁp = Mass flow of sand [kg/s]

µm = Kekentalan campuran [kg/m.s]

ρt = Densitas material [kg/m3]

ID = Inside diameter [m]

OD = Outside diameter [m]

r = Jari-jari [m]

A = Luasan permukaan [m2]

V = kecepatan aliran [m/s]

CA = Corrosion allowance[-]

1

BAB 1

PENDAHULUAN

1.1 Latar Belakang

Perpipaan merupakan suatu media yang digunakan untuk

mendistribusikan sebuah fluida dari equipment ke equipment lain. Jalur perpipaan

terdiri dari beberapa line yang memiliki sebuah nama berguna sebagai informasi

dari spesifikasi pipa pada jalur tersebut mulai dari jenis material pipa, nominal

pipe size (nps), schedule/ketebalan, dan juga jenis fluida yang dialirkan pada line

tersebut. Pemberian nama line sangat penting karena mempermudah dalam proses

maintance and repair yang berhubungan dengan kerusakan pada jalur pipa,

kerusakan yang sering terjadi pada jalur pipa yaitu korosi. Korosi adalah

kerusakan atau degredasi logam akibat reaksi redoks antara suatu logam dengan

berbagai zat di lingkunganya yang menghasilkan senyawa-senyawa yang tidak

dikehendaki. Dalam Bahasa sehari-hari, korosi disebut perkaratan. Contoh korosi

yang paling lazim adalah perkaratan besi (Wikipedia, 2018)

Pada industri yang bergerak pada bidang proses kimia, pastinya terdapat

line yang mendistribusikan fluida bersifat asam yang sangat korosif terhadap

material jenis carbon, sehingga material stainless steel dipilih karena relatif tahan

korosi, hal ini dikarenakan material stainless steel secara umum mengandung unsur

kromium yang membentuk lapisan pasif kromium oksida (Cr2O3) saat bereaksi

dengan oksigen (O2). Lapisan pasif ini dapat mencegah bereaksinya material

dengan zat lainya yang dapat menyebabkan degredasi, namun lapisan tersebut

memiliki batas maksimal konsentrasi asam, jika suatu fluida memiliki konsentrasi

keasaman yang tinggi seperti asam phospat, korosi akan cepat terjadi dan pipa pada

jalur tersebut berpotensi bocor atau berlubang. Maka material stainless steel saat

ini jarang dijadikan material yang mendistribusikan fluida asam dan diganti

menggunakan material non-logam salah satunya yaitu fiber reinforced plastics

(FRP).

Fiberglass reinforced plastics (FRP) atau yang biasa disebut dengan

fiberglass adalah material yang dibuat dari resin, katalis, bahan penguat fiberglass

2

dan additive (bahan tambahan) yang digabung/disusun dan diproses agar dapat

performance yang spesifik sesuai kebutuhan. FRP ini banyak digunakan baik untuk

perabot rumah dan pembuat kapal dan seiring kemajuan teknologi FRP sekarang

juga bisa dijadikan bahan baku pipa karena lebih tahan korosi dan kuat. FRP ini

diresapi dengan resin pada proses laminasi sehingga menjadi suatu bahan yang kuat

dan tahan korosi (Myers, Kyt, & Smith, 2007).Seluruh produsen FRP membuat

komposisi laminasi berdasarkan fluida dan menyusun lapisan mat dan WR sesuai

kebutuhan kekuatan yang dibutuhkan.

Pada Tugas Akhir (TA) ini akan membahas mengenai pengaruh

komposisi hibrid resin DERAKANE 411-157 BTQN EX dengan susunan peletakan

Woven Roving dan Mat terhadap ketahanan korosi serta kekuatan tarik pada

aliran asam phospat untuk mengatasi permasalahan kebocoran pipa. Data

diperoleh dengan cara pengujian laminasi FRP dengan variasi susunan Woven

Roving dan Mat dengan Tensile Properties of plastics mengacu pada ASTM

D-638 serta immersion test yang dilaksanakan mengacu pada ASTM G31 dan

ASTM C581.

1.2 Rumusan Masalah

Rumusan masalah dari penelitian ini antara lain:

1. Bagaimana pengaruh komposisi hibrid derakane 411-157 BQTN EX dengan

variasi susunan Woven Roving dan Mat terhadap ketahanan korosi pada aliran

asam phospat dengan pH 1 dan temperature 700 ?

2. Bagaimana pengaruh komposisi hibrid derakane 411-157 BQTN EX dengan

variasi susunan Woven Roving dan Mat terhadap kekuatan tarik ?

3. Bagaimana menentukan jenis variasi yang optimal terhadap ketahanan korosi

pada aliran asam phospat dan kekuatan tariknya ?

3

1.3 Tujuan Penelitian

Tujuan dalam penelitian ini adalah sebagai berikut :

1. Mengetahui pengaruh komposisi hibrid derakane 411-157 BQTN EX dengan

variasi susunan Woven Roving dan Mat terhadap ketahanan korosi pada aliran

asam phospat dengan pH 1 dan temparatur 700.

2. Mengetahui pengaruh komposisi hibrid derakane 411-157 BQTN EX dengan

variasi susunan Woven Roving dan Mat terhadap kekuatan tarik .

3. Mampu menentukan jenis variasi yang optimal terhadap ketahanan korosi pada

aliran asam phospat dan kekuatan tariknya.

1.4 Manfaat Penelitian

Manfaat dari penelitian ini adalah sebagai berikut :

1. Manfaat bagi penulis

Topik ini dapat menambah ilmu dan pengetahuan bagi penulis yang nantinya

akan diterapkan dalam industri.

2. Manfaat bagi umum

Topik ini dapat dijadikan referensi bagi pembaca dalam menentukan jenis resin,

komposisi resin, dan susunan layer yang sesuai dengan kebutuhan.

3. Manfaat bagi perusahaan

Referensi pengaruh komposisi jenis resin dengan susunan Woven Roving dan

Mat terhadap ketahanan korosi serta kekuatan tarik pada aliran asam phospat

dengan pH 1 dan temperatur 700, sebagai bahan pertimbangan pemilihan

material dalam implementasi teknologi di industri atau produksi.

1.5 Batasan Masalah

Batasan masalah pada penelitian ini adalah sebagai berikut :

1. Temperature fluida yang ditetapkan untuk uji material FRP adalah 700C, dan

asam phospat dengan pH 1.

2. Standart pengujian immersion test yang dilaksanakan mengacu pada ASTM G31

dam ASTMC581 dengan kecepatan aliran 1,72 m/s.

3. Menganalisa ketahanan FRP (Fiberglass Reinforced Plastics) dengan komposisi

hibrid derakane 411 – 157 BQTN EX pada aliran asam phospat di salah satu

4

perusahaan daerah Manyar Roomo Gresik dengan Tensile Properties of Plastics

mengacu pada ASTM D-638.

4. Ketebalan yang digunakan mengacu pada ketebalan pipa 6 inch sch 40 (7,11

mm) dan ASTM C582.

5. Variasi susunan yang digunakan adalah (WR, WR, M, M, M, M, WR, WR),

(WR, M, M, WR, M, M, M, WR), dan (WR, WR, M, WR, WR, M, M, WR).

6. Variasi komposisi resin yang digunakan (100% DEREKANE 411), (75%

DEREKANE 411, 25% 157 BQTN EX), dan (50% DEREKANE 411, 50% 157

BQTN EX).

5

BAB 2

TINJAUAN PUSTAKA

2.1 Klasifikasi Material Pipa

Klasifikasi material pipa dibagi menjadi tiga kelompok berdasarkan

mechanical, chemical, dan physical properties dari Solid Engineering Materials.

Ketiga kelompok tersebut yaitu Metals, Polymers, dan Ceramics. Ketiga material

tersebut dapat dikombinasikan menjadi material baru yang digolongkan dalam jenis

polymers. Rincian setiap klompok klasifikasi material pipa yaitu sebagai berikut

(Makin et al., 2018):

1. Metals merupakan kombinasi satu atau lebih dari metallic element (iron,

aluminium, copper, gold, dan nickel) dan seringkali termasuk nonmetallic

elements (carbon, nitrogen, dan oxygen) dalam jumlah kecil yang sangat relatif.

Dengan melihat kondisi mekanisnya, material metals relatif kaku dan keras,

namun juga elastis, memiliki ketahanan terhadap kepatahan, yang mana

digunakan perhitungan untuk perkembangan yang digunakan dalam aplikasi

strukturnya.

2. Polymers dikenal luas sebagai material plastic dan rubber. Polymers yang umum

diketahui antara lain Polyethylene (PE), Polyprophylene (PP), nylon, Polyvinyl

Chloride (PVC), Polycarbonat (PC), Polystyrene (PS), dan silicone rubber.

Material ini merupakan material Low Density (LD) dan memiliki perbedaan

mechanical characteristics dengan metallics atau ceramics. Polymer tidak

sekaku dan sekuat material tipe lainnya, kebanyakan bersifat elastik dan lentur.

3. Ceramics merupakan gabungan antara metallic dan nonmetallic elements,

seringkali mengandung oxides, nitrides, dan carbides. Sebagai contoh yang

umum, aluminium oxide (atau alumina, Al2O3), silicon dioxide (atau silica,

SiO2), silicon carbides (SiC), silicon nitride (Si3N4). Dengan melihat kondisi

mekanisnya, material ceramic relative kaku dan kuat, secara khusus bersifat

sangat keras dan pada umumnya bersifat sangat kaku (kurang lentur) serta sangat

mudah retak.

6

4. Composite adalah perpaduan dari dua jenis (atau lebih) ketiga Solid Engineering

Materials. Tujuan dari desain polymers adalah untuk mencapai kombinasi

karakteristik properties yang tidak dapat ditunjukkan oleh material tunggal dan

juga menggabungkan karakteristik yang terbaik dari beberapa material. Material

polymers yang umum diketahui adalah fiberglass yang merupakan perpaduan

antara glass fiber yang dilekatkan dengan epoxydan polyester. Glass fiber relatif

kaku dan kuat namun brittle sedangkan polymer bersifat sangat lentur namun

lemah dan fleksibel. Jadi sebagai hasilnya, fiberglass tercipta dengan sifat yang

relatif kaku, kuat, fleksibel, dan lentur serta cukup ringan.

2.2 Fluida dan Karakteristiknya

Fluida adalah zat yang dapat mengalami perubahan bentuk secara terus-

menerus karena gaya gesek yang bekerja terhadapnya, fluida juga dapat dikatakan

sebagai suatu zat yang mengalir. Menurut Henry Liu, (2003) terdapat perbedaan

fluida berdasarkan besarnya tekanan geser dari fluida tersebut, yaitu fluida

Newtonian dan fluida non-Newtonian. Fluida newtonian adalah fluida yang

memiliki tegangan geser mendekati 0 sehingga tidak memerlukan gaya awal untuk

menggerakan fluida tersebut. Sedangkan pada fluida non-Newtonian adalah suatu

fluida yang memiliki tegangan geser jauh dari 0 sehingga diperlukan gaya awalan

untuk menggerakan fluida tersebut. Fluida Newtonian viskositasnya hanya

dipengaruhi perubahan temperatur dan tekanan, viskositas fluida ini tidak

bergantung pada besar gradien kecepatan, contoh fluida ini antara lain udara dan

air. Fluida non-Newtonian viskositasnya selain dipengaruhi oleh temperatur dan

tekanan juga dipengaruhi oleh laju geseran (shear rate), contohnya adalah cat,

lumpur dan lem. Hubungan antara tegangan geser, viskositas dan gradien kecepatan

ditunjukan pada gambar 2.1 Grafik Rheogram fluida Newtonian dan non-

Newtonian, sehingga dapat dituliskan dalam persamaan:

Ʈ = μ𝑑𝑢

𝑑𝑦 ….... (2.1)

Dimana :

μ = Viskositas dinamik (kg/m.s)

𝝉 = Tegangan geser (N/m)

7

𝑑𝑢

𝑑𝑦 = Gradien kecepatan ((m/s)/m)

Gambar 2. 1 Grafik Rheogram fluida Newtonian dan non-Newtonian

(Sumber :(Liu, 2003))

2.2.1 Karakteristik dan sifat fluida

a. Density (ρ)

Density adalah massa dari materi atau zat setiap satuan volumenya. Kerapatan

atau density dari fluida akan mempengaruhi jenis aliran dari fluida, bila ditinjau dari

bilangan Reynolds-nya. Densitas suatu zat atau materi dapat dilihat dari

temperaturnya. Semakin tinggi temperatur zat atau materi maka density dari zat

tersebut akan semakin rendah sehingga kecepatan akan semakin tinggi (Gunawan,

2017). Density dapat dinyatakan dengan persamaan :

ρ = 𝑚

𝑉 (2.2)

Dimana :

ρ = Density (kg/m3)

m = massa (kg)

V = volume (m3)

b. Berat Jenis (ƴ)

White (Dalam Gunawan, Yuspian., Muhammad Hasby dan Muh. Sakti Jaya

2017) mengemukakan bahwa berat jenis suatu zat adalah berat suatu zat persatuan

volume atau merupakan perkalian dari densitas dengan percepatan gravitasi

ƴ = ρ . g (2.3)

Dimana :

8

Ƴ = Berat Jenis (N/m3)


g = Percepatan Gravitasi (m/s2)

c. Specific Gravity (SG)

Munson (Dalam Gunawan, Yuspian., Muhammad Hasby dan Muh. Sakti Jaya

2017) menyatakan bahwa specific Gravity (SG) suatu fluida merupakan rasio

perbandingan densitas atau massa jenis suatu fluida cair terhadap densitas fluida

acuan air pada 4°C dan tekanan atmosfer standar. Specific Gravity dapat dihitung

dengan persamaan :

SG = ρ fluida

ρ air =

ρ fluida

1000kg

m3

…………………………………………………(2.4)

Dimana :

SG = Specific Gravity (Non-Dimensional)

ρ fluida = Densitas fluida tertentu (kg/m3)

ρ air = Densitas air pada temperatur 40 Celcius (kg/m3)

d. Viskositas

Viskositas adalah yang menentukan besar daya tahan fluida terhadap gaya geser.

Hal ini terutama diakibatkan oleh saling ketergantungan molekul-molekul fluida.

Viskositas fluida ini menyebabkan terbentuknya gaya geser antara elemen-

elemenya. Bila suatu fluida mengalami geseran, ia mulai bergerak dengan laju

renggangan yang berbanding terbalik dengan suatu besaran yang disebut koefisien

viskositas, viskositas dinamis atau viskositas mutlak. Viskositas dibagi menjadi dua

macam yaitu: viskositas dinamik atau viskositas mutlak atau absolute viscosity dan

viskositas kinematik.

Viskositas dinamik adalah sifat fluida yang menghubungkan tegangan geser

dengan gerakan fluida. Viskositas dinamik adalah perbandingan rasio tegangan

geser terhadap gradien kecepatan:

𝛍 = τ

𝑑𝑢/𝑑𝑦 (2.5)

Satuan dalam SI Unit μ = N/𝑚2

(𝑚

𝑠)/𝑚

= N/s

𝑚2 = kg

𝑚.𝑠

Dimana :

9

μ = Viskositas dinamik (kg/m.s)

𝝉 = Tegangan geser (N/m)

𝑑𝑢

𝑑𝑦 = Gradien kecepatan ((m/s)/m)

Viskositas kinematik adalah perbandingan antara

viskositas dinamik dengan kerapatan / massa jenis fluida.

v = μ

ρ .…………………………………………………………………….(2.6)

Dimana :

v = Viskositas Kinematik (m2/s)

μ = Viscositas dinamik (kg/m.s)


e. Kecepatan Fluida

Kecepatan fluida (v) didefinisikan besarnya kecepatan aliran yang mengalir

persatuan luas. Mencari kecepatan fluida dapat menggunakan persamaan 2.7

𝑉 =Q

A...........................................................................................................(2.7)

Dimana:

V = kecepatan rata-rata fluida yang mengalir (m/s)

Q = debit fluida (m³/s)

A = luas penampang (m²)

Dalam (Wijaya, Prasojo, & Prayitno, 2018), aliran fluida terbagi berdasarkan

beberapa kategori, diantaranya berdasarkan sifat pergerakannya adalah :

1. Uniform Flow

Merupakan aliran fluida yang terjadi dimana besar dan arah tidak terpengaruh

terhadap jarak. Contoh aliran sungai tidak ada pengaruh adanya bendungan

ataupun penyempitan.

2. Non Uniform Flow

Aliran yang terjadi dimana besar dan arah berubah terhadap jarak. Contoh pada

aliran sungai ada pengaruh pembendungan serta penyempitan ekstrim yang

menyebabkan aliran bertambah cepat atau lambat.

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3. Steady Flow

Merupakan aliran yang terjadi apabila kecepatannya tidak dipengaruhi oleh

waktu, sehingga kecepatannya konstan pada setiap titik pada aliran tersebut.

Contoh pada aliran sungai pada saat tersebut tidak ada hujan atau banjir.

4. Non Steady Flow

Merupakan aliran yang terjadi apabila ada suatu perubahan kecepatan aliran

tersebut terhadap perubahan waktu.

Kemudian fluida cair dibedakan menjadi 3 menurut besarnya nilai reynold

number fluida tersebut yaitu aliran laminar, aliran turbulen, dan aliran transisi.

Untuk penentuan aliran cair laminar dan turbulen ditentukan oleh Reynold

Number (Nomer Reynold). Dalam bukunya, Raswari menentukan bahwa untuk

nilai Reynold :

5. Re < 2000, aliran tersebut termasuk aliran laminar

Aliran laminar ini dijelaskan sebagai aliran fluida, dimana fluida dianggap

mengalir pada lapisan masing-masing dan dengan kecepatan konstan.

Alirannya tetap dan tidak ada 10 pencampuran partikel antara lapisan. Aliran

dengan fluida yang bergerak dalam lapisan-lapisan, atau lamina-lamina dengan

satu lapisan meluncur secara lancar. Dalam aliran laminar ini viskositas

berfungsi untuk meredam kecendrungan terjadinya gerakan relatif antara

lapisan. Sehingga aliran laminar memenuhi hukum viskositas Newton.

6. Re > 2300, aliran tersebut termasuk aliran turbulen

Aliran dimana pergerakan dari partikel – partikel fluida sangat tidak menentu,

karena mengalami percampuran serta putaran partikel antar lapisan, yang

mengakibatkan saling tukar momentum dari satu bagian fluida kebagian fluida

yang lain dalam skala yang besar. Dalam keadaan aliran turbulen maka

turbulensi yang terjadi membangkitkan tegangan geser yang merata diseluruh

fluida sehingga menghasilkan kerugian– kerugian aliran.

7. 2000 ≤ Re ≤ 2300, aliran tersebut termasuk aliran transisi.

Aliran transisi merupakan aliran peralihan dari aliran laminar ke aliran

turbulen.

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2.3 FRP (Fiberglass Reinforced Plastics)

Fiber sudah digunakan sejak tahun 1940an. fiberglass Reinforced Plastics

adalah material komposit yang terbentuk dari 2 komponen utama yaitu resin

sebagai matrik pengikat dan serat (fiber) sebagai penguat. Kelebihan penggunaan

FRP sebagai material adalah relatif lebih ringan (72% dibandingkan dengan

material lain), proses pembangunan relatif sederhana dan cepat ( diluar pembuatan

cetakan dan untuk bendayang dibangun secara seri), tidak bersifat korosif, dan

perawatan yang relatif mudah. Sedangakan kelemahan penggunaan FRP sebagai

material adalah material penyusun FRP yang tidak ramah lingkungan, mudah

terbakar dan material pembuat FRP merupakan material import yang harganya

dipengaruhi fluktuasi rupiah terhadap mata uang asing sehingga dibutuhkan

investasi awal yang lebih besar, selain itu bentuk dan tipe material FRP sangat

tergantung pada desain dan cetakan yang telah dibuat(Makin et al., 2018).

Fiberglass Reinforced Plastics memiliki penguat yang disebut serat gelas

yang memberikan kekuatan pada komposit dan juga mencegah terjadinya retak

sehingga memiliki ketahanan kelelahan yang tinggi. Ikatan serat dengan polimer

akan menahan beban dari serat ke serat yang lain.

Sifat mekanik FRP dikendalikan oleh serat, tipe serat,

panjang serat, fraksi volume fiber, dan arah serat. Sedangkan untuk sifat kimia, sifat

terhadap panas, dan daya tahan berdasarkan sifat polimer yang digunakan .

Kombinasi sifat tersebut menghasilkan komposit FRP yang mempunyai kekakuan

dan kekuatan yang tinggi, ketahanan kelelahan yang tinggi, dan tahan terhadap

korosi. Di sisi lain FRP memiliki keuntungan ekonomis dari segi pemasangan dan

perbaikan ketika terjadi kebocoran.

2.3.1 Bahan-bahan pembuat Fiberglass Reinfoorced Plastics

Fiberglass Reinforced Plastics merupakan bahan yang terbuat dari serat

kaca yang sangat halus. Beberapa bahan penting yang diperlukan dalam proses

pembuatan Fiberglass Reinforced Plastics yaitu:

1. Wax

Wax yang ditunjukan seperti gambar 2. 2 Wax, berfungsi sebagai release agent,

agar hasil pembuatan FRP nantinya mudah dilepas.

12

Gambar 2. 2 Wax (Google, 2018)

2. Mat

Seperti yang ditunjukan pada gambar 2.3 Matt, merupakan salah satu bahan

pembuat Fiberglass Reinforced Plastics yang berupa anyaman mirip jerami

dan terdiri dari beberapa model, dari model anyaman halus sampai dengan

anyaman yang kasar. Berfungsi sebagai salah satu serat penguat campuran

adonan dasar Fiberglass Reinforced Plastic, sewaktu unsur kimia tersebut

bersenyawa dan mengeras, mat berfungsi sebagai pengikatnya. Mat yang

digunakan pada pengujian ini adalah Strand Mat.

Gambar 2. 3 Matt (Google, 2018)

3. Resin

Resin merupakan salah satu bahan pembuat Fiberglass Reinforced Plastics

yang berbentuk cairan kental seperti lem bening. Resin merupakan bahan baku

pembentukan polimer. Adapun jenis resin yang sering digunakan adalah :

a. Polyesters (Orthophalic)

Polyesters merupakan jenis resin sintetis tak jenuh yang dibentuk oleh

reaksi asam organik dan alkohol polihidrat. Polyester resin tahan terhadap

air dan variasi bahan kimia dengan suhu hingga 80°C. Pada gambar 2.4

menunjukan Polyesters Resin sebagai berikut :

13

Gambar 2. 4 Polyesters Resin (Google, 2018)

b. Polyesters (Isophathalic)

Sifat poliester Isophathalic lebih diatas poliester pada umumnya. Tidak

hanya pada ketahanan kimia, mereka dapat diformulasikan agar tahan api

atau untuk melindungi terhadap efek sinar ultraviolet dan wadah untuk

menampungnya ditunjukan seperti pada gambar Gambar 2.5 Polyesters

(Isophathalic).

Gambar 2. 5 Polyesters (Isophathalic)

(Google, 2018)

c. Epoxy

Resin Epoxy sendiri adalah sebuah bahan kimia resin dari hasil polimerisasi

epoxyda. Resin polimerisasi tersebut kemudian dikenal dengan nama resin

thermoset yang membentuk ikatan molekul yang erat dalam suatu struktur

antar polimer. Rangkaian yang membentuk epoxy tersebut memiliki proses

pembentukan awal berupa cairan yang bereaksi secara kimiawi menjadi

padat. Polimer epoxy ini sangat kuat secara mekanis. Polimer epoxy

memiliki sifat tahan terhadap perubahan yang biasanya di miliki unsur-

unsur kimia padat pada umumnya. Sifat rekatnya yang tinggi dihasilkan

selama proses konversi dari cair ke padat. Polimer epoxy memiliki banyak

14

varian sifat yang berbeda tergantung bahan kimia dasar dalam resin. (Ilham

Chaerul Rizqi Siregar, Hartono Yudo, 2017), contoh resin epoxy ditunjukan

pada gambar 2. 6 Epoxy Resin.

Gambar 2. 6 Epoxy Resin

(Google, 2018)

d. Vinyl Ester

Vinyl Ester merupakan hibrida resin poliester dan epoksi yang memiliki

karakteristik, penanganannya, sifat, dan harga umumnya ratarata diantara

kedua resin. Vinyl Ester memiliki ketahanan korosi yang tinggi terhadap

bahan bakar, uap, dan bahan kimia. Contoh vinyl ester ditunjukan pada

Gambar 2.7 Vinyl Ester.

Gambar 2. 7Vinyl Ester

(Google, 2018)

Adapun penelitian kali ini menggunakan Resin Derakane 411-157 BQTN

EX dengan cara di laminasi hand lay-up.

4. Katalis

Katalis adalah untuk mereaksikan polimerisasi resin Fiberglass Reinforced

Plastics, katalis yang dibutuhkan relatif sedikit tapi menentukan kecepatan

pengeringannya atau reaksi. Katalis yang digunakan pada pengujian ini adalah

MEPOXE seperti yang ditunjukan pada gambar 2. 8 Katalis

Gambar 2. 8 Katalis (Google, 2018)

15

5. WR (Woven Roving)

Berbentuk seperti anyaman dengan serat panjang dan tebal. Woven Roving

memiliki sebuah kode tiga angka dibelakang, contoh WR 500. Artinya adalah

WR dengan kepadatan 500 gram per meter persegi (500gr/m2). Woven Roving

yang digunakan pada pengujian ini adalah Strand Roving. Dapat dilihat pada

gambar 2.9 Woven Roving dibawah ini.

Gambar 2. 9Woven Roving (Google, 2018)

2.3.2 Bahan-bahan pendukung Fiberglass Reinfoorced Plastics

Bahan tambahan lain Fiberglass Reinforced Plastics ini adalah bahan yang

digunakan sesuai kebutuhan. Antara lain:

1. Erosil

Bahan dengan bentuk bubuk sangat halus berwarna putih. Berfungsi sebagai

perekat mat agar Fiberglass Reinforced Plastics menjadi kuat .

2. Talk

Bahan berupa bubuk berwarna putih seperti sagu berfungsi sebagai campuran

adonan Fiberglass Reinforced Plastics agar lentur.

3. Aseton

Bahan cairan berwarna bening yang berfungsi untuk mencairkan resin.

4. Cobalt

Cairan kimia yang berwarna kebiru-biruan berfungsi sebagai bahan aktif

pencampuran katalis agar cepat kering terutama apabila kualitas katalis kurang

bagus dan terlalu encer. Bahan ini di kategorikan sebagai penyempurna sebab

tidak semua bengkel menggunakan hal ini tergantung pada kebutuhan dan

kualitas resin yang digunakan. Apabila perbandingan cobalt dengan katalis

lebih tinggi cobalt akan menimbulkan api.

16

5. Mirror

Bahan dengan bentuk seperti pasta dan mempunyai banyak warna yang dapat

menggantikan bahan PVA dan mirror.

6. Pigmant

Pigmant bahan yang digunakan untuk pewarnaan Fiberglass Reinforced

Plastics.

2.3.3 Peralatan Fiberglass Reinfoorced Plastics

Berikut ini peralatan dalam pembuatan Fiberglass Reinforced Plastics.

1. Wadah atau tempat untuk mencampur resin

2. Pengaduk

3. Kuas untuk proses laminasi hand lay-up

4. Kain lap atau majun utuk membersihkan kotoran atau eceran resin.

5. Alat tambahan lain seperti gergaji, gunting, gerinda dan lainnya dibutuhkan

dalam beberapa jenis pekerjaan.

2.4 Penentuan Ketebalan

Menurut ASTM C-582 bahwa setiap susunan yang digunakan harus sesuai

dengan ketebalan yang telah ditentukan seperti yang ditunjukan pada:

Tabel 2. 1 Standart laminate coposition

Sumber: (Specification, 2009)

Dari beberapa macam komposisi susunan yang ada, penelitian

menggunakan tabel 2.1 Standart laminate coposition sebagai acuan penyusun

17

komposit. Dalam penelitian ini menggunakan ketebalan 7 mm dikarenakan

mengacu pada ketebalan pipa berukuran 6”sch 40.

Pengukuran ketebalan dilakukan menggunakan alat MT 200. merupakan

alat pengukur ketebalan ultrasonik digital yang banyak digunakan untuk mengukur

ketebalan fiberglas, plat besi, plat aluminium, kaca, bahan plastik, pipa, pvc /

paralon serta bahan padat lainnya yang memiliki kemampuan rambat gelombang

ultrasonik yang bagus. Contoh alat yang digunakan ditunjukan pada gambar 2.10

MT 200.

Gambar 2. 10 MT 200

(Google, 2018)

2.5 Proses Pembuatan

Ada banyak metode yang digunakan untuk mengubah resin cair dan serat

kaca menjadi struktur padat yang berguna. Berikut beberapa metode dalam

pembuatan FRP (Fiberglass Reinforced Plastic), antara lain : (Paul Kelly, 1999

dalam (Wijaya et al., 2018)).

1. Hand lay-up

Hand lay-up adalah metode manufaktur yang paling umum digunakan untuk

membuat FRP tahan korosi pada proses kimia industri. Untuk memulai, pertama

adalah membuat cetakan yang bisa dibuat dari berbagai macam bahan, termasuk

FRP itu sendiri, dan lebih sering dari bahan kayu. Setelah dibuat cetakannya,

permukaannya dipoles hingga halus. Ini penting karena untuk kemudahan

demoulding. Lapisan resin dioleskan pada serat penguat. menggunakan roler bulu

sampai ketebalan yang dibutuhkan tercapai. Serat yang digunakan dalam proses

WR dan CSM diselingi untuk membentuk lapisan struktural. Adapun beberapa

langkah umum yang digunakan dalam proses pembuatan hand lay-up seperti yang

dijelaskan di bawah ini :

18

1. Persiapan cetakan

Desain cetakan tergantung pada bentuk produk, dimensi, bahan

penguat, jenis resin, dan besarnya tekanan yang dibutuhkan selama

produksi. Desain cetakan juga tergantung pada perkakas, dan biaya tenaga

kerja.

2. Gel coating

Langkah ini diformulasikan khusus untuk peberian warna pada

permukaan cetakan. Lapisan gel hanya digunakan bila diperlukan tampilan

permukaan yang baik.

3. Hand lay-up

Penguatan dalam bentuk chopped strand mat, fabric, dan

woven roving disusun pada permukaan lapisan gel, yang didahului dengan

campuran resin yang telah dioleskan pada cetakan. Campuran resin yang

terdiri dari resin dan katalisator (pengeras) dengan rasio yang ditentukan

diterapkan pada permukaan serat atau kain dengan menggunakan rol dan

dengan lembut menekan cetakan untuk mencapai pemindahan udara dan

saturasi resin. Komposit benar-benar bereaksi di bawah kondisi sekitar

atau dengan bantuan pemanas eksternal.

4. Finishing

Setelah komposit kering, cetakan dapat dilepas dan perakitan dapat

dilakukan seperti pada gambar 2.11 Metode hand lay-up.

Gambar 2. 11 Metode hand lay-up

(Sumber : Reinforced Concrete Design with FRP Composites)

19

2. Filament winding

Gulungan filamen (Filament winding) seperti pada gambar 2.12 Metode

Filament Winding adalah proses mekanik yang paling umum digunakan di industri

manufaktur komposit. Cetakan ditempatkan secara horizontal di mesin dan diputar.

Didalam mesin tersebut terdapat resin WR dan CSM yang diperlukan untuk pelapis

penghalang korosi. Lapisan ini dengan hati-hati digulung oleh operator untuk

menghilangkan udara yang tidak diinginkan. Pembatasnya diperbolehkan untuk gel

dan kemudian CSM digulung ke atasnya. Gulungan struktur dinding dimulai

langsung di CSM. Roda kaca terus menerus ditarik melalui bak berisi resin. Bila

ketebalan yang dibutuhkan telah tercapai, resin dibiarkan mengeras dan mandrel

ditarik. Kadar kaca yang dicapai oleh proses ini pada umumnya 65-75% berat.

Karena sifat kontinyu, hal ini juga sering digunakan untuk produksi yang lebih

besarstruktur diameter seperti tangki dan bejana penyimpanan.

Gambar 2. 12 Metode Filament Winding

(Sumber : https://materialengineeringranggaagung.files.wordpress.com)

3. Spray-up

Dalam proses penyemprotan seperti yang ditunjukan pada gambar 2.13 Metode

Spray Up, cetakan dibuat seperti pada proses pengerjaan tangan hand lay-up.

Selanjutnya, resin dimasukkan ke dalam chopper gun dan serat penguat telah

diletakkan ke dalam cetakan. Setelah terpasang dengan sempurna, resin

disemprotkan pada waktu yang sama. Serat penguat dan resin bertemu satu sama

lain di permukaan cetakan. Kandungan serat yang dicapai dengan proses ini

biasanya antara 25-35% berat. Metode ini jarang digunakan dengan sendirinya

untuk bejana korosi namun digunakan dalam kombinasi dengan filamen yang

berkelok-kelok seperti pada kapal.

https://materialengineeringranggaagung.files.wordpress.com/

20

Gambar 2. 13 Metode Spray Up

(Sumber : https://materialengineeringranggaagung.files.wordpress.com)

4. Drostholm process

Biasanya digunakan untuk menghasilkan sejumlah besar diameter sedang seperti

tangki, atau pipa tekanan medium (sampai 15bar) yang panjang. Contoh perusahaan

yang saat ini terkait dengan proses ini adalah Owens Pipe Corning.

5. Centrifugal casting

Dalam casting sentrifugal, cetakan diputar bersama resin dan serat penguat yang

dipasang pada cetakan. Resin dan serat ditekan terhadap dinding dalam cetakan

dengan gaya sentrifugal, sedemikian rupa sehingga bersentuhan dengan permukaan

cetakan. Setelah resin telah mengering, cetakan dibuka dan ditarik. Metode yang

paling sering digunakan untuk memproduksi silo besar yang digunakan di

pertanian. Contoh perusahaan yang saat ini terkait dengan jenis pipa ini adalah

Hobas.

6. Pultrusion

Selama proses pultrusion yang ditunjukan pada Gambar 2.14 Metode Pultrusion,

serat penguat terus menerus ditarik melalui bak resin yang akan mengeras karena

terkena suhu yang panas. Tingkat produksi bervariasi, tergantung ketebalannya dan

kompleksitas potongan yang diproduksi. Proses tersebut biasanya digunakan untuk

membuat profil, tangga, dan sebagainya.

https://materialengineeringranggaagung.files.wordpress.com/

21

Gambar 2. 14 Metode Pultrusion


7. Resin Transfer Molding (RTM)

Resin transfer molding (RTM) seperti pada gambar 2.15 Alat Resin Transfer

Molding (RTM) adalah proses cetakan tertutup dimana komposit dibentuk di bawah

tekanan rendah (kurang dari 100 psi) [Lawrence et al. 2005; Le Riche dkk. 2003].

Selama pembuatan, penguat serat penguat ditempatkan di cetakan dan diinfuskan

dengan resin dan katalisator, yang dipompa ke dalam cetakan tertutup di bawah

tekanan rendah 40 (psi) sampai 50 (psi). Cetakan kemudian dipanaskan dan

direaksikan untuk membuat bagian komposit. Resin yang digunakan di RTM adalah

poliester (paling umum), ester vinil, epoksi, fenolat, dan hibrida akrilik atau

poliester.

Gambar 2. 15 Alat Resin Transfer Molding (RTM)


Dalam beberapa metode proses fabrikasi yang ada, pada Tugas Akhir ini

menggunakan metode hand lay-up sebagai proses laminasi pelapisan reducer.

22

Dalam permasalahan yang ada di lapangan metode ini dianggap sangat cocok

dikarenakan prosesnya yang mudah digunakan untuk fabrikasi di tempat. Metode

hand lay-up lebih ekonomis disbanding dengan metode yang lain.

Menurut Nicholas P. Cheremisinoff (1995) prosedur pembuatan FRP (Fiber

Reinforced Plastic) adalah dengan mencampurkan bahan resin, catalyst, dan

pigment sesuai ukuran yang telah ditentukan. Selanjutnya, resin yang telah

tercampur difabrikasi dengan reinforcement menggunakan metode hand lay-up.

Resin akan bereaksi dengan reinforcement pada cetakan yang telah ditentukan.

2.6 Pengujian Immersion Test System

Prinsip kerja alat ini adalah spesimen dicelupkan ke dalam larutan asam

phospat. Kondisi pengujian menyesuaikan kondisi dilapangan yang dianggap

linier. Pada pengujian ini, logam uji atau specimen adalah material FRP dengan

variasi penyusunan Mat dan WR. Spesimen berbentuk pelat dengan luas

permukaan antara 2.5cm2 sampai 5cm

2 mengacu pada ASTM G31 dan diuji

menggunakan larutan asam phospat sehingga dapat dicermati proses dan efek fluida

tersebut terhadap material FRP. Untuk mengetahui pengaruhnya diidentifikasi

dengan menimbang berat spesimen sebelum dan sesudah pengujian, sehingga dapat

diketahui berat logam yang hilang karena bereaksi dengan larutan asam phospat.

Standart pengujian immersion test yang dilaksanakan mengacu pada ASTM

G31 (ASTM International, 2004)dan ASTM C581(ASTM Committee D20, 2008)

dengan kecepatan 1,7 m/s.

2.6.1 Metode Weight Loss (Kehilangan Berat)

Metode kehilangan berat adalah perhitungan laju korosi dengan mengukur

kekurangan berat akibat korosi yang terjadi. Metode ini menggunakan jangka

waktu penelitian hingga mendapatkan jumlah kehilangan akibat korosi yang terjadi.

Untuk mendapatkan jumlah kehilangan berat akibat korosi digunakan rumus

sebagai berikut:

𝐶𝑅 =𝑊×𝐾

𝐷𝐴𝑠𝑇…………………………………………………(2.8)

Dimana :

23

CR =Corrosion rate

W =Weight loss (gram)

K =Constant Factor

D =Density of metal (g/cm3)

AS =Surface Area (cm3)

T =Ekposur time (Hour)

Metode ini adalah mengukur kembali berat awal dari benda uji (objek yang

ingin diketahui laju korosi yang terjadi padanya), kekurangan berat dari pada berat

awal merupakan nilai kehilangan berat. Kekurangan berat dikembalikan kedalam

rumus untuk mendapatkan laju kehilangan beratnya.

Metode ini bila dijalankan dengan waktu yang lama dan suistinable dapat

dijadikan acuan terhadap kondisi tempat objek diletakkan (dapat diketahui seberapa

korosif daerah tersebut) juga dapat dijadikan referensi untuk treatment yang harus

diterapkan pada daerah dan kondisi tempat objek tersebut.

2.7 Kekuatan Tarik

Dalam(Makin, Prasojo, & Prayitno, 2018), pengujian tarik adalah dasar

pengujian mekanik yang dipergunakan pada material. Dimana spesimen uji yang

telah distandarisasi, dilakukan pembebanan uniaxial sehingga spesimen uji

mengalami pergerakan dan bertambah panjang hingga akhirnya patah. Pengujian

tarik relatif sederhana, murah dan sangat terstandarisasi dibandingkan pengujian

lain.

Teganggan teknik tersebut diperoleh dengan cara membagi beban yang

diberikan dibagi dengan luas awal penampang uji. Dituliskan seperti dalam

persamaan berikut :

σ = p/Ao……..…………………………………………………… (2.9)

Keterangan :

σ : besarnya tegangan (kg/mm2)

P : beban yang diberikan (kg)

Ao : luas penampang awal benda uji (mm2)

24

Regangan yang digunakan untuk kurva tegangan-regangan teknik adalah

regangan linier rata-rata, yang diperoleh dengan cara membagi perpanjangan yang

dihasilkan setelah pengujian dilakukan dengan panjang awal. Ditulis seperti dalam

persamaan berikut :

e=(L1-Lo)/Lo×100%......................................................................... (2.9)

Keterangan :

e : besar regangan

L1 : panjang benda uji setelah pengujian (mm)

Lo : panjang awal benda uji (mm)

∈= ∆L/Lo………………………………………………….............. (2.10)

Keterangan :

ϵ : besar regangan

∆L : L1-Lo (mm)

Lo : panjang awal benda uji (mm)

Bentuk dan besaran pada kurva tegangan-regangan suatu logam tergantung

pada komposisi, perlakuan panas, deformasi plastis, laju regangan, temperatur dan

keadaan tegangan yang menentukan selama pengujian. Parameter-parameter yang

digunakan untuk menggambarkan kurva tegangan-regangan logam adalah

kekuatan tarik, kekuatan luluh atau titik luluh, persentase perpanjangan dan

pengaruh luas. Parameter pertama adalah parameter kekuatan, sedangkan dua yang

terakhir menyatakan keuletan bahan.

Pada hasil uji tarik, spesimen akan mengalami pengecilan pada daerah

penampang. Maka dari itu, didapatkan persamaan rumus seperti dibawah ini:

φ=(Ao-A1)/A0×100%........................................................................ (2.11)

Keterangan :

φ : besar pengecilan penampang (%)

Ao : luas penampang awal (mm2)

A1 : luas penampang setelah uji tarik (mm2)

Bentuk kurva tegangan-regangan pada daerah elastis tegangan berbanding

lurus terhadap regangan. Deformasi tidak berubah pada pembebanan, daerah

rengangan yang tidak menimbulkan deformasi apabila beban dihilangkan disebut

daerah elastis. Deformasi pada daerah ini bersifat permanen, meskipun bebannya

25

dihilangkan. Tegangan yang dibutuhkan untuk menghasilkan deformasi plastis

akan bertambah besar dengan bertambahnya regangan plastis.

Pada mulanya pengerasan regngan lebih besar dari yang dibutuhkan untuk

mengimbangi penurunan luas penampang lintang benda uji dan tegangan

teknik(sebanding dengan beban F) yang terus bertambah, dengan bertambahnya

regangan. Akhirnya dicapai suatu titik dimana pengaruh luas penampang lintang

lebih besar dibandingkan pertambahan deformasi beban yang diakibatkan oleh

pengeras regangan. Keadaan ini untuk pertama kalinya dicapai pada suatu titik

dalam beban uji yang sedikit lebih lemah dibandingkan dengan keadaan tanpa

beban. Seluruh deformasi plastis berikutnya terpusat pada daerah tersebut dan

benda uji mulai mengalami penyempitan secara lokal. Karena penurunan luas

penampang lintang lebih cepat daripada pertambahan deformasi akibat pengerasan

regangan, beban sebenarnya yang diperlukan untuk mengubah bentuk benda uji

akan berkurang dan demikian juga tegangan teknik pada persamaan (2.1) akan

berkurang hingga terjadi patah.

Dari kurva uji tarik yang diperoleh dari hasil pengujian akan didapatkan

beberapa sifat mekanik yang dimiliki oleh benda uji, sifat-sifat mekanik tersebut

antara lain [Dieter,1993]:

1. Kekuatan Tarik

2. Kekuatan Luluh dari material

3. Keuletan dari material

4. Modulus Elastik dari material

5. Kelentingan dari suatu material

6. Ketangguhan

Kekuatan yang ditentukan dari suatu hasil pengujian tarik adalah kuat luluh

(Yield Strength) dan kuat tarik (Ultimate Tensile Strength). Kekuatan tarik atau

kekuatan tarik maksimum (Ultimate Tensile Strength), adalah beban maksimum

dibagi luas penampang lintang awal benda uji.

σu=Pmaks/Ao…………………………………………………….. (2.12)

Keterangan :

σu : kuat tarik (kg/mm2)

P maks : beban maksimum (kg)

26

Ao : luas penampang awal (mm2)

Untuk FRP kekuatan tariknya harus dikaitkan dengan beban maksimum

dimana FRP dapat menahan sesumbu untuk keadaan yang sangat terbatas.

Tegangan tarik adalah nilai yang paling sering ditulisakan sebagai hasil suatu uji

tarik, tetapi pada kenyataanya nilai tersebut kurang bersifat mendasar dalam

kaitanya dengan kekuatan beban. Untuk logam-logam kekuatan tariknya harus

dikaitkan dengan beban maksimum, dimana logam dapat menahan beban sesumbu

untuk keadaan yang sangat terbatas. Akan ditunjukan bahwa nilai tersebut kaitanya

dengan kekuatan logam kecil sekali kegunaannya untuk tegangan yang lebih

kompleks, yakni yang biasa ditemui.

Untuk berapa lama, telah menjadi kebiasaan mendasar kekuatan struktur

pada kekuatan tarik, dikurangi dengan faktor keamanan yang sesuai.

Kecenderungan yang banyak ditemui adalah menggunakan pendekatan yang lebih

rasional yakni mendasarkan rancangan statis logam pada kekuatan luluhnya. Akan

tetapi, karena jauh lebih praktis menggunakan kekuatan tarik untuk menentukan

kekuatan bahan, maka metode ini lebih banyak dikenal, dan merupakan metode

identifikasi bahan yang sangat berguna, mirip dengan kegunaan komposisi kimia

untuk mengenali bahan. Selanjutnya, karena kekuatan tarik mudah ditentukan dan

merupakan sifat yang mudah dihasilkan kembali. Kekuatan tersebut berguna untuk

keperluan spesifikasi dan kontrol kualitas bahan. Korelasi empiris yang diperluas

antara kekuatan tarik dan sifat-sifat bahan misalnya kekerasan dan kekutan lelah,

sering dipergunakan.

Tegangan dimana deformasi plastis mulai teramati tergantung pada

kepekaan pengukuran regangan. Sebagaian besar bahan mengalami perubahan sifat

dari elastik menjadi plastik yang berlangsung sedikit demi sedikit, dan titik dimana

deformasi plastis mulai terjadi dan sukar ditentukan secara telit. Telah digunakan

berbagai kriteria permulaan batas luluh yang tergantung pada keteitian pengukuran

regangan dan data-data yang akan digunakan.

1. Batas elastik sejati berdasarkan pada pengukuran regangan mikro pada

skala regangan 2x10-6 inci/inci. Batasan elastik nilainya sangat rendah

dan dikaitkan dengan gerakan beberapa ratus dislokasi.

27

2. Batas proporsional adalah tegangan tertinggi untuk daerah hubungan

proporsional antara tegangan-regangan. Harga ini diperoleh dengan cara

mengamati dari bagian garis lurus kurva tegangan-regangan.

Batas elastik adalah tegangan terbesar yang masih dapat ditahan oleh bahan

tanpa terjadi regangan sisa permanen yang terukur pada saat beban telah ditiadakan.

Dengan bertambahnya ketelitian pengukuran regangan, nilai batas elastiknya

menurun hingga suatu batas yang sama dengan batas elastik sejati yang diperoleh

dengan cara pengukuran regangan mikro. Dengan ketelitian regangan yang sering

digunakan pada kuliah rekayasa (10-4 inci/inci), batas elastik lebih besar daripada

batas proporsional. Penentuan batas elastik memerlukan prosedur pengujian yang

diberi beban- tak diberi beban (loading-unloading).

2.7.1 Kekuatan luluh (yield strength)

Dalam Penelitiannya(Makin et al., 2018), salah satu kekutan yang biasanya

diketahui dari suatu hasil pengujian tarik adalah luluh (Yield Strength). Kekuatan

luluh merupakan titik yang menunjukkan perubahan dari deformasi elastis ke

deformasi plastis. Besar tegangan luluh dituliskan seperti pada persamaan sebagai

berikut :

σyield = Pyield/Ao……...………………………………………….....(2.13)

Keterangan :

σyield : besarnya tegangan luluh (kg/mm2)

Pyield : besarnya beban di titik yield (kg)

Ao : luas penampang awal benda uji (mm2)

Tegangan dimana deformasi plastis atau batas luluh mulai teramati

tergantung pada kepekaan pengukuran regangan. Sehingga besar bahan mengalami

perubahan sifat dari elastis menjadi plastis yang berlangsung sedikit demi sedikit,

dan titik dimana deformasi plastis mulai terjadi dan sukar ditentukan secara teliti.

Cara yang baik untuk mengamati kekuatan luluh offset adalah setelah benda

uji diberi pembebanan hingga 0,2% kekuatan luluh offset dan kemudian pada saat

beban ditiadakan maka beban ujinya akan bertambah panjang 0,1% sampai 0,2%,

lebih panjang daripada saat dalam keadaan diam. Tegangan offset di Britania Raya

28

sering dinyatakan sebagai tegangan uji (Proff Stress), dimana harga offset 0,1%

atau 0,5%.

2.7.2 Modulus elastisitas

Modulus elastisitas merupakan ukuran kekuatan keelastisitasnya dari suatu

bahan. Makin besar modulusnya, maka semakin kecil regangan elastis yang

dihasilkan akibat pemberian tegangan. Modulus elastisitas ditentukan oleh gaya

ikat antar atom, karena gaya-gaya ini tidak dapat berubah tanpa terjadi perubahan

mendasar pada sifat bahannya. Maka modulus elastisitas salah satu sifat-sifat

mekanik yang tidak dapat diubah. Sifat ini hanya sedikit berubah oleh adanya

penambahan paduan, perlakuan panas, atau pengerjaan dingin. Secara matematis,

persamaan modulus elastisitas dapat ditulis sebagai berikut:

E = ε/σ………………..........................................................................(2.14)

Keterangan :

E : modulus elastisitas (kg/mm2)

σ : tegangan (kg/mm2)

ε : regangan

2.7.2 Pengukuran keliatan dan keuletan

Keuletan adalah kemampuan suatu bahan sewaktu menahan beban pada saat

diberikan penetrasi dan akan kembali ke bentuk semula. Secara umum pengukuran

keuletan dilakukan untuk memenuhi kepentingan tiga buah hal [Dieter,1993] yaitu:

1. Untuk menunjukkan elongasi dimana suatu bahan dapat berdeformasi

tanpa terjadi patah dalam suatu proses pembentukan logam, misalnya

pengerolan dan ekstrusi.

2. Untuk memberi petunjuk secara umum kepada perancang mengenai

kemampuan logam untuk mengalir secara plastis sebelum patah.

Sebagai petunjuk adanya perubahan permukaan kemurnian atau kondisi

pegolahan.

29

2.7.3 Dimensi Spesimen Benda Uji

Setelah melakukan persiapan pembuatan dan pencetakan benda uji,

diperlukan suatu komposisi serat gelas yang sesuai. Penggunaan jumlah layer dalam

pembuatan serat gelas disesuaikan dengan kebutuhan ketebalan spesimen benda uji

yaitu 7mm. Dimensi spesimen sesuai dengan ASTM D638 Standart Test Method

for Tensile Properties of Plastics section 02a ditunjukan pada gambar 2.16

Pengukuran dimensi benda uji dan gambar 2.17 Tabel Detail dimensi spesimen

benda uji.

Gambar 2. 16 Pengukuran dimensi benda uji (ASTM, 2003)

Gambar 2. 17 Tabel Detail dimensi spesimen benda uji (ASTM, 2003)

2.8 Kerangka Konseptual

Kerangka konseptual digunakan untuk mengetahui persamaan dan

perbedaan antara jurnal penelitian sebelumnya, dengan penelitan yang sedang

dikerjakan. Dari beberapa persamaan, dapat digunakan sebegai acuan dalam

pengerjaan penelitian.

30

Tugas Akhir (2019)

Analisa pengaruh

komposisi hibrid

derakane 411 – fw 21

exl dengan variasi

susunan mat dan woven

roving terhadap

ketahanan korosi serta

kekuatan Tarik

padafluida asam

phospat

Elsevier B.V (2009)

Fiber-reinforced polymer

composite materials with high

specific strength and excellent

solid particle erosion resistance

1. Fluida Slurry

2. Pengaruh serat penguat

dalam laju erosi

3. Pengujian tensile test

4. Erosion wear test

5. Pengujian dengan

scanning electron

micrograph

Amar Patnaik (2010)

Performance sensitivity of

hybrid phenolic composites in

friction braking : effect of

ceramic and aramid fibre

combination

1. Hibrid resin

2. Friction test

3. Micrograph test

Dicky Hidayat (2013)

Sifat mekanik paduan hibrid

epoksi – poliamin dengan

poliuretan

1. Hibrid resin

2. Tensile test

3. Thermogravimatric

analysis test

4. Micrograph test

1. Fluida Slurry

2. Hibrid resin

3. Pengaruh serat

penguat dalam

laju erosi

4. Tensile test

5. Erosion test

Ahyanul Makin (2017)

Pengaruh variasi susunan woven

fofing dan mat terhadap

ketahanan korosi serta kekuatan

Tarik pada aliran asam phospat

1. Pengaruh serat penguat

2. Fluida diam dan

bergerak

3. Tensile test

4. Erosion test

Kerangka Konseptual (Qian, Bao, Takatera, Kemmochi, & Yamanaka,

2010),(Patnaik, Kumar, Satapathy, & Tomar, 2010),(Hidayat,

2013),dan(Makin et al., 2018)

31

BAB 3

METODOLOGI PENELITIAN

3.1 Diagram Alir

MULAI

Identifikasi Masalah

Perumusan Masalah dan Tujuan

Studi Literatur Studi Lapangan

Pengumpulan Data

Pemilihan Material FRP

Pembuatan FRP dengan variasi

yang telah ditentukan

Tensile Test

Immersion Test

Analisa

Pengukuran berat awal spesimen

SELESAI

Kesimpulan & Saran

Pengukuran berat akhir spesimen

Pembuatan Spesimen FRP

Gambar 3. 1 Diagram Alir

32

3.2 Langkah penelitian

Penelitian ini dilakukan dengan menggunakan hasil data pengujian

korosi erosi terhadap FRP (Fiberglass Reinforced Plastics). Susunan FRP

terdiri dari 3 variasi susunan mat serta WR dan 3 variasi komposisi hibrid

resin. Waktu pengujian dilakukan selama 24 jam untuk setiap perlakuan agar

dapat terlihat perbedaan laju korosi erosi dari setiap perbedaan variai FRP dan

laju alir. Sebelum melakukan pengujian, spesimen ditimbang dengan

menggunakan timbangan digital. Penimbangan dilakukan, berguna untuk

mengetahui berat material sebelum diuji. Setelah mengetahui data berat material,

kemudian dilakukan pengujian korosi yang mengacu pada ASTM 2004 G 31 dan

ASTM C581. Setelah itu, dilakukan penimbangan spesimen untuk mengetahui

laju korosi erosinya.Langkah penelitian dalam pengerjaan Tugas Akhir ini

ditunjukkan pada gambar 3.1 Diagram Alir.

3.2.1 Tahap Identifikasi Awal

Tahap identifikasi awal ditujukan untuk melakukan identifikasi

mengenai permasalahan dan penetapan tujuan dalam penelitian ini. Adapun

isi dari tahap identifikasi awal antara lain sebagai berikut :

1. Identifikasi masalah, perumusan masalah dan penetapan tujuan

Pada tahap ini dilakukan identifikasi beberapa permasalahan yang didapatkan

pada saat melakukan pengamatan dan pemikiran sehingga bisa dilakukan

suatu penelitian. Setelah masalah itu diidentifikasi, kemudian dirumuskan

masalah-masalah yang akan diselesaikan pada penelitian ini. Pada tahap ini

juga dilakukan penetapan tujuan tentang apa yang ingin dicapai dan

manfaatnya bagi pihak terkait serta bagi penelitian selanjutnya. Tahap-tahap

ini merupakan dasar tentang apa yang dilakukan selama penelitian.

Pada penelitian ini diangkat permasalahan mengenai pengujian pengaruh

komposisi hibrid esin serta susunan variasi woven roving dan mat terhadap

ketahanan korosi dan kekuatan tarik pada material FRP untuk fluida

Phosphat Acid (PA) di PT. Petro Jordan Abadi.

33

2. Studi Lapangan

Studi lapangan dilakukan untuk mengetahui kondisi real dari objek penelitian

yang akan diteliti. Pengamatan dilakukan dengan cara pembandingan

dari gambar desain dan kondisi real di lapangan.

3. Studi Literatur

Pada tahap ini dilakukan pengumpulan teori-teori yang relevan dengan

penelitian ini yang nantinya akan digunakan sebagai acuan dalam

penelitian ini. Dalam penelitian ini teori-teori yang diangkat adalah teori

yang berhubungan dengan pengujian material.

3.2.2 Tahap Pengumpulan Data

Tahap pengumpulan data merupakan tahap untuk mengumpulkan data

yang berhubungan dengan permasalahan yang didapat. Data yang dikumpulkan

antara lain data fluida yang mengalir seperti flowrate, pressure, temperature,

dan density.

3.2.3 Tahap Laminasi dan Pengolahan Data

Proses laminasi dalam pembuatan FRP ini meliputi persiapaan laminasi

sampai dengan alat-alat dan bahan-bahan yang digunakan dalam laminasi itu

sendiri. Tahap pengolahan data merupakan tindak lanjut dari pengumpulan data

yang telah didapatkan, hal-hal tersebut antara lain:

3. Persiapan Alat dan Bahan Laminasi

Alat-alat yang digunakan untuk membuat spesimen antara lain adalah

sebagai berikut :

1. Kuas

2. Majun

3. Kuas Rol

4. Klem

5. Papan Kramik

6. Guntik

7. Gerinda

34

Bahan-bahan yang digunakan untuk membuat spesimen antara lain sebagai

berikut :

1. Chopped strand matt 300 (CSM300)

2. Woven roving 600 (WR600)

3. Resin

4. Katalis

2. Persiapan Alat dan Bahan Laminasi

Proses laminasi merupakan proses penyusunan lapisan CSM dan WR yang

direkatkan dengan cairan resin yang telah dicampur dengan katalis, sehingga

menghasilkan material padat yang disebut FRP (Fiberglass Reinforced

Plastics).

Langkah-langkah kerja yang dilakukan pada proses laminasi

pembuatan spesimen yaitu :

a. Membersihkan papan kramik sebagai landasan pembuatan

laminasi FRP.

b. Pemotongan woven roving dan matt sesuai kebutuhan

pembuatan spesimen.

c. Pencampuran resin dan katalis.

d. Memulai proses laminasi FRP dengan awalan pemberian

campuran resin dan katalis pada matt dan woven roving.

e. Untuk menghilangkan gelembung udara yang kemungkinan

muncul saat pelapisan, dapat menggunakan kuas rol untuk

memadatkannya.

f. Mengeringkan laminasi selama 60 menit atau sampai laminasi

tersebut benar-benar kering dan tidak retak untuk di angkat dari

kramik.

g. Proses pemotongan spesimen yang sudah kering dengan

gerinda.

3. Proses pembuatan susunan FRP dan perhitungan luas permukaan

Proses pembuatan laminasi FRP mengacu pada ASTM D638. Penyusunan

material FRP dengan variasi susunan woven roving dan mat seperti pada

35

gambar 3.2, 3.3, dan 3.4 dilakukan untuk mengetahui pengaruh variasi

terhadap ketahanan korosi pada fluida asam phospat dan kekuatan tarik.

Gambar 3. 4 Variasi susunan WR dan Mat 50% Derakane 411 50% 157

BQTN EX

Woven Roving

Mat

Mat

Woven Roving

Mat

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Mat

Woven Roving

Woven Roving

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Mat

Mat

Mat

Mat

Woven Roving

Woven Roving

Gambar 3. 2 Variasi susunan WR dan Mat 100% Derakane 411

Woven Roving

Mat

Mat

Woven Roving

Mat

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Mat

Mat

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Woven Roving

Mat

Woven Roving

Woven Roving

Mat

Mat

Woven Roving

Gambar 3. 3 Variasi susunan WR dan Mat 75% Derakane 411 25% 157

BQTN EX

Woven Roving

Mat

Mat

Woven Roving

Mat

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Mat

Mat

Mat

Mat

Woven Roving

Woven Roving

Woven Roving

Woven Roving

Mat

Woven Roving

Woven Roving

Mat

Mat

Woven Roving

36

Setelah itu dilakukan perhitungan luas area untuk menghitung luasan spesimen

yang terpapar oleh fluida pada saat pengujian. Perhitungan luasan area yeng

terpapar menggunakan rumus sebagai berikut:

Tabel 3. 1 Gambar dan Rumus Perhitungan Luas Permukaan

Gambar No Bagian Rumus

1 Depan &

Belakang L= (p x l) – (πr²)

2 Atas &

Bawah L= p x t

3 Kanan &

Kiri L = l x t

4 Tengah L = 2πrt

4. Pengujian immersion pada material FRP

Pengujian immersion dilakukan untuk mengetahui pengaruh fluida terhadap

material FRP (Fiberglass Reinforced Plastics) dengan temperature 700C

dan pH asam phospat 1 mengacu pada ASTM G31 dan ASTM C581

dengan kecepatan 1,7 m/s.

5. Pengujian Tarik material FRP

Pengujian dilakukan untuk mengetahui kekuatan tarik material FRP

terhadap pengaruh variasi woven roving dan mat pada fluida asam phospat

mengacu pada ASTM D-638. Pada pengujian tersebut terdapat 18 spesimen

dan dimensi spesimen ditunjukan pada gambar 3.5 dan tabel 3.2.

Gambar 3. 5 Dimensi Spesimen

2

3

1

1

2

3

4

37

Tabel 3. 2 Ukuran dimensi spesimen pengujian tarik

Dimensions 7 mm

type I(mm)

W-Width of narrow section 13

L-Length of narrow section 57

WO-Width overall 19

LO-Length overall 165

G-Gage Length 50

D-Distance between grips 115

R-Radius of fillet 76

3.2.4 Tahap Analisa dan Kesimpulan

Tahap ini adalah tahap akhir dari penelitian, yang terdapat dalam tahap

ini adalah:

a. Analisa

Pada tahap ini dilakukan analisa terhadap data-data yang telah

diolah. Analisa ini menitik beratkan pada pengujian material.

b. Tahap Kesimpulan

Tahap ini merupakan tahap pengambilan kesimpulandari pengolahan dan

analisa data yang telah dilakukan. Saran dimaksudkan sebagai

masukan untuk perusahaan maupun untuk penelitian yang akan

dilakukan selanjutnya sebagai bahan pertimbangan dan referensi.

3.3 Bahan dan Alat Pengujian

Alat dan bahan yang digunakan utuk pengujian laju korosi sebagai

berikut:

Bahan : Material FRP dengan variasi hibrid resin serta susunan Mat dan Woven

Roving, dan Fluida Asam Phospat

Alat : Skema alat yang digunakan untuk pengujian immersion test ditunjukkan

pada Gambar 3.6 Skema Alat

38

Gambar 3. 6 Skema Alat

3.4 Waktu dan Tempat Penelitian

Waktu

Waktu pengerjaan dan pelaksanaan tugas akhir ini dimulai pada akhir

semester 7 yaitu diawali dengan pengajuan proposal tugas akhir dan

dilanjutkan pada semester 8 dengan waktu pengerjaan efektif ± 5 bulan.

Tempat

Tempat pelaksanaan tugas akhir ini adalah di kampus Politeknik

Perkapalan Negeri Surabaya (PPNS) dan di salah satu perusahaan daerah

Manyar Roomo Gresik.

Berikut tabel 3.3 menjelaskan tentang detail dari jadwal penelitian yang

akan dilakukan pada penelitian ini.

39

Tabel 3. 3 Jadwal Penelitian

40

(Halaman Ini Sengaja Dikosongkan)

41

BAB 4

ANALISA DAN PENGOLAHAN DATA

4.1 Data Penelitian

Untuk melakukan perhitungan dan pengujian laju korosi, diperlukan data-

data yang dapat menunjang perhitungan. Data–data tersebut meliputi karakteristik

fluida, data material, data luas area yang terpapar, dan data selisih berat spesimen.

4.1.1 Data Fluida

Pada perusahaan memiliki data spesifikasi fluida yang beroprasi seperti

pada tabel 4.1. Data Fluida Asam Phospat, pengujian immersion test menggunakan

debit sebesar 0,032 m3/s sesuai dengan debit yang beroperasi pada perusahaan.

Tabel 4. 1 Data Fluida Asam Phospat

Nama Besaran Satuan Besaran Satuan

Temperatur Desain

(TD)

185 F 85 C

Temperatur Operasi

(TO)

158 F 70 C

Tekanan Desain (PD) 15,50 psig 0,1 MPa

Tekanan Operasi (PO) 15,50 psig 0,1 MPa

Densitas Partikel (𝝆p) 1,92 ton/m3 1922 kg/m3

Densitas Campuran

(𝝆m)

1,44 ton/m3 1440 kg/m3

Viskositas Campuran

(µm)

200 MPa.s 0,2 g/cm2.s

pH fluida 1 - - -

Debit (Q) 115,2 m3/hr 0,032 m3/s

Diameter Partikel (dP) 0,002 in 0,0508 mm

Mass Flow of Particle

(ṁP)

8282,8 lb/hr 1,044 kg/s

Konsentrasi (%) Komposisi Phosporic Acid Slurry (PAS)

Water Asam

Fosfat

(H3PO4)

Asam

Sulfat

(H2SO4)

Gypsum

47 12 6 35

42

4.1.2 Data Material

Data density material Fiber Reinforcing Plastics yang digunakan pada

perhitungan didapatkan dari tabel 4.2 Data Material FRP

Tabel 4. 2 Data Material FRP

4.2 Perhitungan Luas Area yang Terpapar

Beberapa bagian luas area yang terpapar dan rumus yang digunakan

ditunjukan pada tabel 3.1 gambar dan rumus perhitungan luas permukaan, dan hasil

perhitungan luas area yang terpapar ditunjukan pada tabel 4.3 Luas Area Total, bisa

dilihat pada tabel tersebut nilai total luasan area dipengaruhi oleh jumlah Woven

Rofing. Semakin banyak Woven Roving pada susunan layernya, nilai total luasan

area semakin luas dikarenakan layer Woven Roving menambah ketebalan spesimen.

Pada spesimen variasi hibrid resin 75% DERAKANE 411- 25% 157 BQTN EX

dengan variasi layer 2 (w, w, m, w, w, m, m, w) memiliki luas area total terbesar

yaitu 81,376 cm2 dikarenakan memiliki 4 Woven Roving dan memiliki dimensi yang

paling panjang dari variasi lainya yaitu panjang 6,2 cm dan lebar 5,3cm, nilai luas

area total didapatkan dari jumlah luasan depan, belakang, kanan, kiri, atas, bawah,

dan tengah yaitu 65,2451 cm2, 65,2451 cm2 , 6,89 cm2, 6,89 cm2, 8,06 cm2, 8,06

cm2, dan 1,1226 cm2.

43

Tabel 4. 3 Luas Area Total

44

4.3 Perhitungan Kecepatan

Perhitungan kecepatan dilakukan dengan cara sebagai berikut:

Diketahui Diameter Pipa 6“ Sch 40

ID = 154,08 mm…………………......……………..(4.1.2 Data Material)

OD = 168,3 mm……......………………………..…..(4.1.2 Data Material)

Q = 0,032 m³/s……………………………………….(4.1.1 Data Fluida)

Menghitung kecepatan aliran :

V = Q

A …………………………………………………….(Rumus Debit)

=0,032

m3

s

0,25 π d2

= 0,032

m3

s

0,25 π 0,154 x 0,154 m2

= 1,72 m/s

Dari perhitungan di atas ditemukan kecepatan fluida asam fosfat adalah 1,72

m/s. Setelah itu dikonversi menjadi satuan rpm untuk menghitung banyaknya

putaran dalam pengujian tiap menitnya.

𝑅𝑝𝑚 =60.000 x speed in m/s

π x diameter (mm) ……………………(rumus konversi v ke rpm)

=60.000 x 1,72 m/s

π x 220( mm)

= 149,316 rpm

Selanjutnya dilakukan Pengujian immersion test yang dilakukan selama 24

jam dengan suhu fluida sebesar 70°C dan kecepatan putaran yang dilakukan pada

proses immersion test yaitu sebesar 150 rpm.

4.4 Uji ImmersionTest

Sebelum melakukan pengujian dilakukan pengukuran berat awal yang

bertujuan untuk mengetahui perbedaan hasil sebelum dan sesudah pengujian.

Pengujian immersion test dilakukan selama 24 jam dengan suhu fluida sebesar

70°C (dokumentasi lama pengujian dan suhu pengujian di tunjukan pada Lampiran

C-2 Lama Pengujian Immersion Test). Setelah dilakukannya pengujian pada setiap

spesimen. Dilakukan pengukuran berat kembali untuk mengetahui perubahan yang

45

terjadi pada setiap spesimen. Hasil pngukuran berat seperti pada tabel 4.4

pengurangan berat spesimen FRP.Selisih pengurangan berat spesimen dipengaruhi

oleh varisi layer dan variasi hibrid resin, semakin banyak Woven Roving pada

variasi layer dan semakin banyak prosentase resin DERAKANE 411 semakin kecil

selisih berat spesimen, bisa dilihat pada tabel 4.4 variasi spesimen yang memiliki

selisih berat paling kecil terdapat pada variasi hibrid resin 100% DERAKANE 411

dan 75% DERAKANE 411- 25% 157 BQTN EX dengan variasi layer 3 (w, w, m,

w, w, m, m, w) yaitu 0,0003 gram dari sini bisa kita ketahui pada hibrid resin dengan

prosentase 75% DERAKANE 411 masih mampu mempertahankan pengurangan

berat terhadap fluida asam phospat dengan suhu 700 dan pH1.

Tabel 4. 4 Pengurangan Berat Spesimen FRP

No

Kode

Spesi

men

Variasi Berat

Layer : Woven Roving

(w) Mat (m)

Resin

DERA

KAN

E 411

(%)

157

BQTN

EX

(%)

Awal

(g)

Akhir

(g)

Selisih

(g)

1 1.3.1 w, m, m, w, m, m, m, w 100 0 27.3011 27.3006 0.0005

2 1.3.2 w, m, m, w, m, m, m, w 100 0 25.9362 25.9358 0.0004

3 1.4.1 w, w, m, m, m, m, w, w 100 0 27.1505 27.1501 0.0004

4 1.4.2 w, w, m, m, m, m, w, w 100 0 22.3514 22.3510 0.0004

5 1.5.1 w, w, m, w, w, m, m, w 100 0 33.4869 33.4865 0.0004

6 1.5.2 w, w, m, w, w, m, m, w 100 0 32.7042 32.7039 0.0003

7 2.3.1 w, m, m, w, m, m, m, w 75 25 29.7968 29.7963 0.0005

8 2.3.2 w, m, m, w, m, m, m, w 75 25 26.5991 26.5987 0.0004

9 2.4.1 w, w, m, m, m, m, w, w 75 25 23.0598 23.0594 0.0004

10 2.4.2 w, w, m, m, m, m, w, w 75 25 25.3208 25.3204 0.0004

11 2.5.1 w, w, m, w, w, m, m, w 75 25 26.8049 26.8046 0.0003

12 2.5.2 w, w, m, w, w, m, m, w 75 25 28.8665 28.8661 0.0004

13 3.3.1 w, m, m, w, m, m, m, w 50 50 19.3842 19.3836 0.0006

14 3.3.2 w, m, m, w, m, m, m, w 50 50 20.2418 20.2412 0.0006

15 3.4.1 w, w, m, m, m, m, w, w 50 50 24.2217 24.2212 0.0005

16 3.4.2 w, w, m, m, m, m, w, w 50 50 29.0538 29.0533 0.0005

17 3.5.1 w, w, m, w, w, m, m, w 50 50 30.4691 30.4687 0.0004

18 3.5.2 w, w, m, w, w, m, m, w 50 50 25.9197 25.9191 0.0006

46

4.5 Analisa Perhitungan Corrosion Rate FRP

Setelah didapatkan data pengurangan pada spesimen dan luas area total,

dilakukan perhitungan corrosion rate dengan mengacu pada standart ASTM G31 :

Corrossion Rate =k . w

A .T .𝗉 ……………………………………(ASTM G31)

k = 87600 ……………………………………..…..(ASTM G31)

Time = 24 jam

𝘱 material = 1,6608 g/cm²……………………………(4.1.2 Data Material)

w = Tabel 4.4 Pengurangan Berat Spesimen

A = Tabel 4.5 Luas Area

Dari data perhitungan manual corrosion rate yang terdapat pada lampiran

C-3 Perhitungan Manual Laju Korosi FRP, dapat disimpulkan menjadi tabel 4.6

Corrosion Rate FRP

Tabel 4. 5 Corrosion Rate FRP

No Kode

Spesimen

Variasi

Corrosion

Rate(mm/year) Average Layer : Woven Roving

(w) Mat (m)

Resin

DERAKANE

411 (%)

157

BQTN

EX

(%)

1 1.3.1 w, m, m, w, m, m, m, w 100 0 0.013959 0.012563

2 1.3.2 w, m, m, w, m, m, m, w 100 0 0.011167

3 1.4.1 w, w, m, m, m, m, w, w 100 0 0.010996 0.010996

4 1.4.2 w, w, m, m, m, m, w, w 100 0 0.010996

5 1.5.1 w, w, m, w, w, m, m, w 100 0 0.01099 0.009616

6 1.5.2 w, w, m, w, w, m, m, w 100 0 0.008242

7 2.3.1 w, m, m, w, m, m, m, w 75 25 0.014168 0.012751

8 2.3.2 w, m, m, w, m, m, m, w 75 25 0.011334

9 2.4.1 w, w, m, m, m, m, w, w 75 25 0.010811 0.010811

10 2.4.2 w, w, m, m, m, m, w, w 75 25 0.010811

11 2.5.1 w, w, m, w, w, m, m, w 75 25 0.008122 0.009476

12 2.5.2 w, w, m, w, w, m, m, w 75 25 0.01083

13 3.3.1 w, m, m, w, m, m, m, w 50 50 0.016409 0.016409

14 3.3.2 w, m, m, w, m, m, m, w 50 50 0.016409

15 3.4.1 w, w, m, m, m, m, w, w 50 50 0.013984 0.013984

16 3.4.2 w, w, m, m, m, m, w, w 50 50 0.013984

17 3.5.1 w, w, m, w, w, m, m, w 50 50 0.010968 0.013709

18 3.5.2 w, w, m, w, w, m, m, w 50 50 0.016451

47

Nilai corrosion rate dari spesimen FRP hibrid resin (50% DERAKANE 411

50% 157 BQTN EX) dengan variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 0,01641

mm/year, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 0,01398 mm/year, variasi

layer 3 (w, w, m, w, w, m, m, w) yaitu 0,01371 mm/year, spesimen FRP hibrid resin

(75% DERAKANE 411 25% 157 BQTN EX) dengan variasi layer 1 (w, m, m, w,

m, m, m, w) yaitu 0,01275 mm/year, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu

0,01081 mm/year, variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 0,00948 mm/year,

spesimen FRP hibrid resin (100% DERAKANE 411) dengan variasi layer 1 (w, m,

m, w, m, m, m, w) yaitu 0,01256 mm/year, variasi layer 2 (w, w, m, m, m, m, w,

w) yaitu 0,010996 mm/year, variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 0,00962

mm/year. Selanjutnya, dapat dianalisa laju korosi FRP seperti pada gambar 4.1

Grafik Pengaruh hibrid resin dengan variasi susunan mat dan woven roving

terhadap ketahan korosi pada fluida asam phospat dengan pH1 dan temperature

70°.

Pada Gambar 4.1 Grafik Pengaruh hibrid resin dengan variasi susunan mat

dan woven roving terhadap ketahan korosipada fluida asam phospat dengan pH1

dan temperature 70°, didapatkan nilai corrosion rate spesimen FRP (Fiber

Reinforced Plastic) hibrid resin (50% DERAKANE 411 50% 157 BQTN EX) lebih

tinggi dibandingkan spesimen FRP hibrid resin (75% DERAKANE 411 25% 157

BQTN EX) dan (100% DERAKANE 411), dan didapatkan nilai corrosion rate

spesimen FRP dengan variasi layer 1 (w, m, m, w, m, m, m, w) lebih tinggi

dibandingkan spesimen FRP dengan variasi layer 2 (w, w, m, m, m, m, w, w) dan

layer 3 (w, w, m, w, w, m, m, w). Nilai corrosion rate tertinggi didapatkan dari


variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 0,01641 mm/year, sedangkan Nilai

corrosion rate terendah didapatkan dari spesimen FRP hibrid resin (75%

DERAKANE 411 25% 157 BQTN EX) dengan variasi layer 3 (w, w, m, w, w, m,

m, w) yaitu 0,00948 mm/year. Sehingga semakin tinggi prosentase resin 157 BQTN

EX dan semakin sedikit layer woven roving corrosion rate pada spesimen FRP,

maka semakin besar nilai corrosion ratenya.

48

jhb

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

Variasi Layer 1 Variasi Layer 2 Variasi Layer 3

Co

rro

sio

n R

ate

(m

m/y

ear)

Pengaruh hibrid resin dengan variasi susunanmat dan woven roving terhadap ketahan korosi

pada fluida asam phospat dengan pH1 dan temperature 70°

100%DERAKANE

75% DERAKANE411 25%157 BQTN EX

50% DERAKANE411 50%157 BQTN EX

Gambar 4. 1 Grafik Pengaruh hibrid resin dengan variasi susunan mat dan woven roving terhadap ketahan korosi

pada fluida asam phospat dengan pH1 dan temperature 70°

WOVEN ROVING

MAT

Variasi Susunan Mat dan Woven

Roving

49

4.6 Analisa Kekuatan Tarik FRP

Data kekuatan tarik didapatkan setelah melakukan pengujian tarik yang

dilakukan di balai riset Jagir Surabaya, dokumen hasil pengujian tarik ditunjukan

pada Lampiran D hasil pengujian tarik, dari hasil pengujian tarik dapat disimpulkan

menjadi tabel 4.5 Kekuatan Tarik FRP.

Tabel 4. 6 Kekuatan Tarik FRP

Nilai kekuatan tarik dari spesimen FRP hibrid resin (50% DERAKANE 411


MPa, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 134,15 MPa, variasi layer 3 (w,

w, m, w, w, m, m, w) yaitu 164,6 MPa, spesimen FRP hibrid resin (75%

DERAKANE 411 25% 157 BQTN EX) dengan variasi layer 1 (w, m, m, w, m, m,

m, w) yaitu 116,9 MPa, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 157,5 MPa,

variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 190,3 MPa, spesimen FRP hibrid

No Kode

Spesimen

Variasi

Kekuatan

Tarik

(MPa)

Average Layer : Woven Roving

(w) Mat (m)

Resin

DERAKANE

411 (%)

157

BQTN

EX

(%)

1 1.3.1 w, m, m, w, m, m, m, w 100 0 138,9 144,55

2 1.3.2 w, m, m, w, m, m, m, w 100 0 150,2

3 1.4.1 w, w, m, m, m, m, w, w 100 0 182,4 179,35

4 1.4.2 w, w, m, m, m, m, w, w 100 0 176,3

5 1.5.1 w, w, m, w, w, m, m, w 100 0 198,7 201,1

6 1.5.2 w, w, m, w, w, m, m, w 100 0 203,5

7 2.3.1 w, m, m, w, m, m, m, w 75 25 105 116,9

8 2.3.2 w, m, m, w, m, m, m, w 75 25 128,8

9 2.4.1 w, w, m, m, m, m, w, w 75 25 157,9 157,5

10 2.4.2 w, w, m, m, m, m, w, w 75 25 157,1

11 2.5.1 w, w, m, w, w, m, m, w 75 25 191,2 190,3

12 2.5.2 w, w, m, w, w, m, m, w 75 25 189,4

13 3.3.1 w, m, m, w, m, m, m, w 50 50 94,8 98,75

14 3.3.2 w, m, m, w, m, m, m, w 50 50 102,7

15 3.4.1 w, w, m, m, m, m, w, w 50 50 137,6 134,15

16 3.4.2 w, w, m, m, m, m, w, w 50 50 130,7

17 3.5.1 w, w, m, w, w, m, m, w 50 50 163,1 164,6

18 3.5.2 w, w, m, w, w, m, m, w 50 50 166,1

50

resin (100% DERAKANE 411) dengan variasi layer 1 (w, m, m, w, m, m, m, w)

yaitu 144,55 MPa, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 179,35 MPa,

variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 201,1 MPa. Selanjutnya, dapat

dianalisa kekuatan tarik seperti pada gambar 4.2 Grafik Pengaruh hibrid resin

dengan variasi susunan mat dan woven roving terhadap kekuatan tarik FRP.

Pada gambar 4. 2 Grafik Pengaruh hibrid resin dengan variasi susunan mat

dan woven roving terhadap kekuatan tarik FRP, didapatkan nilai kekuatan tarik

spesimen FRP (Fiber Reinforced Plastic) hibrid resin (100% DERAKANE 411)

lebih tinggi dibandingkan spesimen FRP hibrid resin (75% DERAKANE 411 25%

157 BQTN EX) dan (50% DERAKANE 411 50% 157 BQTN EX), dan didapatkan

nilai kekuatan tarik spesimen FRP dengan variasi layer 3 (w, w, m, w, w, m, m, w)

lebih tinggi dibandingkan spesimen FRP dengan variasi layer 2 (w, w, m, m, m, m,

w, w) dan layer 1 (w, m, m, w, m, m, m, w). Nilai kekuatan tarik tertinggi

didapatkan dari spesimen FRP hibrid resin (100% DERAKANE 411) dengan

variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 201,1 MPa, sedangkan Nilai kekuatan

tarik terendah didapatkan dari spesimen FRP hibrid resin (50% DERAKANE 411


MPa. Sehingga semakin tinggi prosentase resin DERAKANE 411 dan semakin

banyak layer woven roving kekuatan tarik pada spesimen FRP, maka semakin besar

nilai kekuatan tariknya.

51

-

50.00

100.00

150.00

200.00

250.00

1 2 3

Kek

uat

an T

arik

(M

Pa)

Pengaruh hibrid resin dengan variasi mat dan woven roving terhadap kekuatan tarik FRP

100% DERAKANE 411

75% DERAKANE 411 25% 157BQTN EX

50% DERAKANE 411 50% 157BQTN EX

MAT

WOVEN ROVING Variasi Susunan Mat dan Woven

Roving

Gambar 4. 2 Grafik Pengaruh hibrid resin dengan variasi susunan mat dan woven roving terhadap kekuatan tarik FRP

52

4.3.3 Analisa Variasi Optimum

Untuk mempermudah analisa, dibuatlah grafik seperti pada gambar 4.3

Grafik analisa variasi optimum FRP. Berdasarkan gambar 4.3 Grafik Anaisa

Variasi OptimumVariasi, dari sembilan variasi spesimen, spesimen yang tahan

korosi terhadap fluida asam phospat dengan pH1 dan temperatur 70° dan memiliki

kekuatan tarik tinggi yaitu spesimen FRP hibrid resin (75% DERAKANE 411 25%

157 BQTN EX) dengan variasi layer 3 (w, w, m, w, w, m, m, w), corrosion rate

yang dimiliki sebesar 0,00948 mm/year, sedangkan nilai corrosion rate dari


variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 0,01641 mm/year, variasi layer 2 (w,

w, m, m, m, m, w, w) yaitu 0,01398 mm/year, variasi layer 3 (w, w, m, w, w, m, m,

w) yaitu 0,01371 mm/year, spesimen FRP hibrid resin (75% DERAKANE 411 25%

157 BQTN EX) dengan variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 0,01275

mm/year, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 0,01081 mm/year, variasi

layer 3 (w, w, m, w, w, m, m, w) yaitu 0,00948 mm/year, spesimen FRP hibrid resin

(100% DERAKANE 411) dengan variasi layer 1 (w, m, m, w, m, m, m, w) yaitu

0,01256 mm/year, variasi layer 2 (w, w, m, m, m, m, w, w) yaitu 0,010996 mm/year,

variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 0,00962 mm/year. Dan kekuatan tarik

yang dimiliki sebesar 201,1 MPa, sedangkan nilai kekuatan tarik dari spesimen FRP

hibrid resin (50% DERAKANE 411 50% 157 BQTN EX) dengan variasi layer 1

(w, m, m, w, m, m, m, w) yaitu 98,75 MPa, variasi layer 2 (w, w, m, m, m, m, w,

w) yaitu 134,15 MPa, variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 164,6 MPa,


variasi layer 1 (w, m, m, w, m, m, m, w) yaitu 116,9 MPa, variasi layer 2 (w, w, m,

m, m, m, w, w) yaitu 157,5 MPa, variasi layer 3 (w, w, m, w, w, m, m, w) yaitu

190,3 MPa, spesimen FRP hibrid resin (100% DERAKANE 411) dengan variasi

layer 1 (w, m, m, w, m, m, m, w) yaitu 144,55 MPa, variasi layer 2 (w, w, m, m, m,

m, w, w) yaitu 179,35 MPa, variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 201,1

MPa.

53

Gambar 4. 3 Grafik Analisa Variasi Optimum

Grafik analisa variasi optimum FRP

55

BAB 5

KESIMPULAN DAN SARAN

5.1 Kesimpulan

Berdasarkan hasil analisa dan perhitungan, dapat menjadi kesimpulan

sebagai berikut :

1. Nilai corrosion rate tertinggi didapatkan dari spesimen FRP hibrid resin (50%

DERAKANE 411 50% 157 BQTN EX) dengan variasi layer 1 (w, m, m, w, m,

m, m, w) yaitu 0,01641 mm/year, sedangkan Nilai corrosion rate terendah

didapatkan dari spesimen FRP hibrid resin (75% DERAKANE 411 25% 157

BQTN EX) dengan variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 0,00948

mm/year. Sehingga semakin tinggi prosentase resin 157 BQTN EX dan

semakin sedikit layer woven roving corrosion rate pada spesimen FRP, maka

semakin besar nilai corrosion ratenya.

2. Nilai kekuatan tarik tertinggi didapatkan dari spesimen FRP hibrid resin (100%

DERAKANE 411) dengan variasi layer 3 (w, w, m, w, w, m, m, w) yaitu 201,1

MPa, sedangkan Nilai kekuatan tarik terendah didapatkan dari spesimen FRP

hibrid resin (50% DERAKANE 411 50% 157 BQTN EX) dengan variasi layer

1 (w, m, m, w, m, m, m, w) yaitu 98,75 MPa. Sehingga semakin tinggi

prosentase resin DERAKANE 411 dan semakin banyak layer woven roving

kekuatan tarik pada spesimen FRP, maka semakin besar nilai kekuatan

tariknya.

3. Dari sembilan variasi spesimen, variasi spesimen yang tahan korosi terhadap

fluida asam phospat dengan pH1 dan temperatur 70° dan memiliki kekuatan

tarik tinggi yaitu spesimen FRP hibrid resin (75% DERAKANE 411 25% 157

BQTN EX) dengan variasi layer 3 (w, w, m, w, w, m, m, w).

56

5.2 Saran

Selanjutnya dari pembahasan penelitian ini, dapat dirangkum beberapa

saran yang berkaitan dengan penelitian adalah sebagai berikut :

1. Untuk penelitian selanjutnya disarankan untuk menggunakan variasi spesimen

FRP hibrid resin 157 BQTN EX dengan persentase 60-90 agar mendapatkan

data yang lebih akurat.

2. Untuk penelitian selanjutnya disarankan untuk meggnunakan variasi spesimen

FRP dengan susunan layer yang terbuat dari serat alam seperti serat yang

terbuat dari tumbuhan eceng gondok agar mendapatkan manfaat yang lebih

terhadap lingkungan.

57

DAFTAR PUSTAKA

ASTM. (2003). American Society for Testing and Materials. Standard test method

for tensile properties of plastics (D 638 - 02a). Astm, 08, 46–58.

https://doi.org/10.1520/D0638-14.1

ASTM Committee D20. (2008). Practice for Determining Chemical Resistance of

Thermosetting Resins Used in Glass-Fiber-Reinforced Structures Intended for

Liquid Service, 08, 1–5. Retrieved from

http://www.astm.org/doiLink.cgi?C581

ASTM International. (2004). ASTM-G31–72 Standard Practice for Laboratory

Immersion Corrosion Testing of Metals. American Society for Testing and

Materials, 72(Reapproved), 1–8. https://doi.org/10.1520/G0031-72R04

Google. (2018). google_image. Retrieved December 29, 2018, from

https://www.google.co.id/imghp?hl=id

Hidayat, D. (2013). Sifat Mekanik Paduan Hibrid Epoksi-, 1(1), 1–6.

Ilham Chaerul Rizqi Siregar, Hartono Yudo, K. (2017). Jurnal teknik perkapalan,

5(1), 163–172.

Makin, A., Prasojo, B., Teknik, J., Kapal, P., Perkapalan, P., & Surabaya, N. (2018).

PENGARUH VARIASI SUSUNAN WOVEN ROFING DAN MAT, 4.

Myers, T. J., Kyt, H. K., & Smith, T. R. (2007). Environmental stress-corrosion

cracking of fiberglass : Lessons learned from failures in the chemical industry,

142, 695–704. https://doi.org/10.1016/j.jhazmat.2006.06.132

Patnaik, A., Kumar, M., Satapathy, B. K., & Tomar, B. S. (2010). Performance

sensitivity of hybrid phenolic composites in friction braking: Effect of ceramic

and aramid fibre combination. Wear, 269(11–12), 891–899.

https://doi.org/10.1016/j.wear.2010.08.023

Qian, D., Bao, L., Takatera, M., Kemmochi, K., & Yamanaka, A. (2010). Fiber-

reinforced polymer composite materials with high specific strength and

excellent solid particle erosion resistance. Wear, 268(3–4), 637–642.

https://doi.org/10.1016/j.wear.2009.08.038

Specification, S. (2009). Standard Specification for Contact-Molded Reinforced

Thermosetting Plastic ( RTP ) Laminates for Corrosion-Resistant Equipment

1. Test, 08(April), 1–8. https://doi.org/10.1520/C0582-09.2

Wikipedia. (2018). korosi. Retrieved December 29, 2018, from

https://id.wikipedia.org/wiki/Korosi

59

LAMPIRAN

Lampiran B-1 Perhitungan Luas Area yang terpapar

Berikut merupakan perhitungan manual luas area spesimen fluida bergerak,

diketahui :

Luas area spesimen 1.3.1

Luas area 1 = p x l – (π x r²)

= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,6 cm

= 3,72 cm²

Luas area 4 = p x t

= 6,2 cm x 0,6 cm

= 3,72 cm²

Luas area 5 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²

Luas area 6 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²

Luas area 7 = 2 x π x r x t

= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²

Luas Total = Luas 1 + Luas 2 + Luas 3 + luas 4 + Luas 5 + Luas 6 + Luas 7

= 32,00254 cm² + 32,00254 cm² + 3,72 cm² + 3,72 cm² + 3,12 cm²

+ 3,12 cm² + 1,0362 cm²

= 78.7213 cm²



= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,6 cm

= 3,72 cm²

Luas area 4 = p x t

= 6,2 cm x 0,6 cm

= 3,72 cm²

Luas area 5 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²

Luas area 6 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²


= 32,00254 cm² + 32,00254 cm² + 3,72 cm² + 3,72 cm² + 3,12 cm²

+ 3,12 cm² + 1,0362 cm²

= 78.7213 cm²



= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5.2 cm x 0,65 cm

= 3,38 cm²

Luas area 6 = l x t

= 5.2 cm x 0,65 cm

= 3,38 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,1226 cm²


= 32,00254 cm² + 32,00254 cm² + 4,03 cm² + 4,03 cm² + 3,38 cm²

+ 3,38 cm² + 1,1226 cm²

= 79,9476 cm²



= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5.2 cm x 0,65 cm

= 3,38 cm²

Luas area 6 = l x t

= 5.2 cm x 0,65 cm

= 3,38 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,1226 cm²


= 32,00254 cm² + 32,00254 cm² + 4,03 cm² + 4,03 cm² + 3,38 cm²

+ 3,38 cm² + 1,1226 cm²

= 79,9476 cm²



= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²


= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²

Luas area 3 = p x t

= 6,1 cm x 0,7 cm

= 4,27 cm²

Luas area 4 = p x t

= 6,1 cm x 0,7 cm

= 4,27 cm²

Luas area 5 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²

Luas area 6 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 31,48254 cm² + 31,48254 cm² + 4,27 cm² + 4,27 cm² + 3,64 cm²

+ 3,64 cm² + 1,2089 cm²

= 79,9940 cm²



= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²


= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²

Luas area 3 = p x t

= 6,1 cm x 0,7 cm

= 4,27 cm²

Luas area 4 = p x t

= 6,1 cm x 0,7 cm

= 4,27 cm²

Luas area 5 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²

Luas area 6 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 31,48254 cm² + 31,48254 cm² + 4,27 cm² + 4,27 cm² + 3,64 cm²

+ 3,64 cm² + 1,2089 cm²

= 79,9940 cm²



= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²


= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²

Luas area 3 = p x t

= 6,1cm x 0,6 cm

= 3.66 cm²

Luas area 4 = p x t

= 6,1cm x 0,6 cm

= 3.66 cm²

Luas area 5 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²

Luas area 6 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²


= 31,48254 cm² + 31,48254 cm² + 3.66 cm² + 3.66 cm² + 3,12 cm²+

3,12 cm² + 1,0362 cm²

= 77,5613 cm²



= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²


= 6,1 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,48254 cm²

Luas area 3 = p x t

= 6,1cm x 0,6 cm

= 3.66 cm²

Luas area 4 = p x t

= 6,1cm x 0,6 cm

= 3.66 cm²

Luas area 5 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²

Luas area 6 = l x t

= 5.2 cm x 0,6 cm

= 3,12 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²


= 31,48254 cm² + 31,48254 cm² + 3.66 cm² + 3.66 cm² + 3,12 cm²+

3,12 cm² + 1,0362 cm²

= 77,5613 cm²



= 6,2 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,62254 cm²


= 6,2 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,62254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5.3 cm x 0,65 cm

= 3.445 cm²

Luas area 6 = l x t

= 5.3 cm x 0,65 cm

= 3,445 cm²


= 2 x 3,14 x 0,275 cm x 0,65 cm

= 1,1226 cm²


= 32,62254 cm² + 32,62254 cm² + 4,03 cm² + 4,03 cm² + 3,445 cm²

+ 3,445 cm² + 1,1226 cm²

= 81,3176 cm²



= 6,2 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,62254 cm²


= 6,2 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,62254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5.3 cm x 0,65 cm

= 3.445 cm²

Luas area 6 = l x t

= 5.3 cm x 0,65 cm

= 3,445 cm²


= 2 x 3,14 x 0,275 cm x 0,65 cm

= 1,1226 cm²


= 32,62254 cm² + 32,62254 cm² + 4,03 cm² + 4,03 cm² + 3,445 cm²

+ 3,445 cm² + 1,1226 cm²

= 81,3176 cm²



= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,7 cm

= 4,34 cm²

Luas area 4 = p x t

= 6,2 cm x 0,7 cm

= 4,34 cm²

Luas area 5 = l x t

= 5,2 cm x 0,7 cm

= 3,64 cm²

Luas area 6 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 32,00254 cm² + 32,00254 cm² + 4,34 cm² + 4,34 cm² + 3,64 cm²

+ 3,64 cm² + 1,2089 cm²

= 81,1740 cm²



= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²


= 6,2 cm x 5,2 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,00254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,7 cm

= 4,34 cm²

Luas area 4 = p x t

= 6,2 cm x 0,7 cm

= 4,34 cm²

Luas area 5 = l x t

= 5,2 cm x 0,7 cm

= 3,64 cm²

Luas area 6 = l x t

= 5.2 cm x 0,7 cm

= 3,64 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 32,00254 cm² + 32,00254 cm² + 4,34 cm² + 4,34 cm² + 3,64 cm²

+ 3,64 cm² + 1,2089 cm²

= 81,1740 cm²



= 6 cm x 5,5 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,76254 cm²


= 6 cm x 5,5 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,76254 cm²

Luas area 3 = p x t

= 6 cm x 0,6 cm

= 3,6 cm²

Luas area 4 = p x t

= 6 cm x 0,6 cm

= 3,6 cm²

Luas area 5 = l x t

= 5,5 cm x 0,6 cm

= 3,3 cm²

Luas area 6 = l x t

= 5,5 cm x 0,6 cm

= 3,3 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²


= 32,76254 cm² + 32,76254 cm² + 3,6 cm² + 3,6 cm² + 3,3 cm² +

3,3 cm² + 1,0362 cm²

= 80,3613 cm²



= 6 cm x 5,5 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,76254 cm²


= 6 cm x 5,5 cm – (3,14 x 0,275 cm x 0,275 cm)

= 32,76254 cm²

Luas area 3 = p x t

= 6 cm x 0,6 cm

= 3,6 cm²

Luas area 4 = p x t

= 6 cm x 0,6 cm

= 3,6 cm²

Luas area 5 = l x t

= 5,5 cm x 0,6 cm

= 3,3 cm²

Luas area 6 = l x t

= 5,5 cm x 0,6 cm

= 3,3 cm²


= 2 x 3,14 x 0,275 cm x 0,6 cm

= 1,0362 cm²


= 32,76254 cm² + 32,76254 cm² + 3,6 cm² + 3,6 cm² + 3,3 cm² +

3,3 cm² + 1,0362 cm²

= 80,3613 cm²



= 6,2 cm x 5,1 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,38254 cm²


= 6,2 cm x 5,1 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,38254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5,1 cm x 0,65 cm

= 3,315 cm²

Luas area 6 = l x t

= 5,1 cm x 0,65 cm

= 3,315 cm²


= 2 x 3,14 x 0,275 cm x 0,65 cm

= 1,1226 cm²


= 31,38254 cm² + 31,38254 cm² + 4,03 cm² + 4,03 cm² + 3,315 cm²

+ 3,315 cm² + 1,1226 cm²

= 78,5776 cm²



= 6,2 cm x 5,1 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,38254 cm²


= 6,2 cm x 5,1 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,38254 cm²

Luas area 3 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 4 = p x t

= 6,2 cm x 0,65 cm

= 4,03 cm²

Luas area 5 = l x t

= 5,1 cm x 0,65 cm

= 3,315 cm²

Luas area 6 = l x t

= 5,1 cm x 0,65 cm

= 3,315 cm²


= 2 x 3,14 x 0,275 cm x 0,65 cm

= 1,1226 cm²


= 31,38254 cm² + 31,38254 cm² + 4,03 cm² + 4,03 cm² + 3,315 cm²

+ 3,315 cm² + 1,1226 cm²

= 78,5776 cm²



= 6 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,56254 cm²


= 6 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,56254 cm²

Luas area 3 = p x t

= 6 cm x 0,7 cm

= 4,2 cm²

Luas area 4 = p x t

= 6 cm x 0,7 cm

= 4,2 cm²

Luas area 5 = l x t

= 5,3 cm x 0,7 cm

= 3,71 cm²

Luas area 6 = l x t

= 5,3 cm x 0,7 cm

= 3,71 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 31,56254 cm² + 31,56254 cm² + 4,2 cm² + 4,2 cm² + 3,71 cm² +

3,71 cm² + 1,2089 cm²

= 80,154 cm²



= 6 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,56254 cm²


= 6 cm x 5,3 cm – (3,14 x 0,275 cm x 0,275 cm)

= 31,56254 cm²

Luas area 3 = p x t

= 6 cm x 0,7 cm

= 4,2 cm²

Luas area 4 = p x t

= 6 cm x 0,7 cm

= 4,2 cm²

Luas area 5 = l x t

= 5,3 cm x 0,7 cm

= 3,71 cm²

Luas area 6 = l x t

= 5,3 cm x 0,7 cm

= 3,71 cm²


= 2 x 3,14 x 0,275 cm x 0,7 cm

= 1,2089 cm²


= 31,56254 cm² + 31,56254 cm² + 4,2 cm² + 4,2 cm² + 3,71 cm² +

3,71 cm² + 1,2089 cm²

= 80,154 cm²

Lampiran C-1 Dokumentasi pengukuran berat spesimen

Kode spesimen 1.3.1 (awal-akhir)



Lampiran C-2 Dokumentasi Lama Pengujian Immersion Test

Pengujian pertama

Pengujian kedua

Pengujian ketiga

Pengujian keempat

Pengujian kelima

Pengujian keenam

Pengujian ketuju

Pengujian kedelapan

Pengujian kesembilan

Lampiran C-3 Perhitungan Manual Laju Korosi FRP

Berikut merupakan perhitungan manual corrosion rate yang dilakukan :

Immersion Test Fluida Bergerak

Diketahui :

k = 87600 mm/y

Time = 24 jam

𝘱 material = 1,6608 g/cm

Kode spesimen 1.3.1

Corrossion rate =k . w

A .T .𝗉

=87600 . 0,0005

78,72128 .24 .1,6608

= 0,013959 mm/years

Kode spesimen 1.3.2


A .T .𝗉

=87600 . 0,0004

78,72128 .24 .1,6608

= 0,011167 mm/years

Kode spesimen 1.4.1


A .T .𝗉

=87600 . 0,0004

79,94763 .24 .1,6608

= 0,010996 mm/years

Kode spesimen 1.4.2


A .T .𝗉

=87600 . 0,0004

79,94763 .24 .1,6608

= 0,010996 mm/years

Kode spesimen 1.5.1


A .T .𝗉

=87600 . 0,0004

79,99398 .24 .1,6608

= 0,01099 mm/years

Kode spesimen 1.5.2


A .T .𝗉

=87600 . 0,0003

79,99398 .24 .1,6608

= 0,008242 mm/years

Kode spesimen 2.3.1


A .T .𝗉

=87600 . 0,0005

77,56128 .24 .1,6608

= 0,014168 mm/years

Kode spesimen 2.3.2


A .T .𝗉

=87600 . 0,0004

77,56128 .24 .1,6608

= 0,011334 mm/years

Kode spesimen 2.4.1


A .T .𝗉

=87600 . 0,0004

81,31763 .24 .1,6608

= 0,010811 mm/years

Kode spesimen 2.4.2


A .T .𝗉

=87600 . 0,0004

81,31763 .24 .1,6608

= 0,010811 mm/years

Kode spesimen 2.5.1


A .T .𝗉

=87600 . 0,0003

81,17398 .24 .1,6608

= 0,008122 mm/years

Kode spesimen 2.5.2


A .T .𝗉

=87600 . 0,0004

81,17398 .24 .1,6608

= 0,01083 mm/years

Kode spesimen 3.3.1


A .T .𝗉

=87600 . 0,0006

80,36128 .24 .1,6608

= 0,016409 mm/years

Kode spesimen 3.3.2


A .T .𝗉

=87600 . 0,0006

80,36128 .24 .1,6608

= 0,016409 mm/years

Kode spesimen 3.4.1


A .T .𝗉

=87600 . 0,0005

78,57763 .24 .1,6608

= 0,013984 mm/years

Kode spesimen 3.4.2


A .T .𝗉

=87600 . 0,0005

78,57763 .24 .1,6608

= 0,013984 mm/years

Kode spesimen 3.5.1


A .T .𝗉

=87600 . 0,0004

80,15398 .24 .1,6608

= 0,010968 mm/years

Kode spesimen 3.5.2


A .T .𝗉

=87600 . 0,0006

80,15398 .24 .1,6608

= 0,016451 mm/years

BADAN PENELITIAN DAN PENGEMBANGAN INDUSTRI BALAI RISET DAN STANDARISASI INDUSTRI SURABAYA

LABORATORIUM PENGUJIAN DAN KALIBRASI

BARISTAND INDUSTRI SURABAYA Jl. Jagir Wonokromo No. 360 Surabaya(60244), Telp. (0321) 8410054, Fax. (031) 8410480

http:/baristandsurabaya.kemenperin.go.id/

LAPORAN PENGUJIAN

Test Report No.04510~04512/19/LHU/3/V/2019

NO.ANALISA : P. 04513 – P. 05487 Analisa No. KOMODITI : Fiber FRP Commodity DIBUAT UNTUK : RYAN DINATA PRIYO PAMUNGKAS Excecuted For

ALAMAT : Mulyosari Gang Bhaskara I no 11 Surabaya Adress

DITERIMA TANGGAL : 13 Mei 2019

Received Date

URAIAN SAMPEL : Telah diterima sampel fiber FRP dengan data sebagai berikut :

Detail of Sample

a. Bentuk : Benda Uji Tarik

b. Merk / Kode : Ryan Dinata P.P.

c. Keadaan luar : Baik

d. Ukuran

Tebal, mm : 6-7

Sampel tersebut diatas telah dilakukan pengujian uji Tarik

TANGGAL PENGUJIAN : 29 Mei 2019

Tested Date

METODE UJI : Sesuai Permintaan

Test Method

METODE : -

PENGAMBILAN CONTOH

Received Date

HASIL PENGUJIAN : Terlampir

Test Result

DITERBITKAN TANGGAL : 29 Mei 2019

Issued Date





Nomor Analisa : P. 04513 – P. 05487

Jenis Sampel : Fiber FRP

Merk / Kode : Ryan Dinata Priyo Pamungkas

Ukuran Tebal, mm : 6-7

No Parameter Uji Satuan

Hasil Uji

V100B V75B V50B

1 2 3 1 2 3 1 2 3

Uji Tarik :

1 Batas Ulur Mpa 136 172,8 187,7 120,3 141,2 167,2 95,3 121,3 155,3

2 Kuat Tarik Mpa 150,2 176,3 203,5 128,8 157,1 189,4 102,7 130,7 166,1

3 Regang % 2,4 2,5 2,3 2,4 2,5 2,3 2,4 1,5 3,8

No Parameter Uji Satuan

Hasil Uji

V100A V75A V50A

1 2 3 1 2 3 1 2 3

Uji Tarik :

1 Batas Ulur Mpa 128,2 166,5 151,3 96,1 156,5 168 88,2 126,4 156,8

2 Kuat Tarik Mpa 138,9 182,4 198,7 105 167,9 191,2 94,8 137,6 163,1

3 Regang % 2,3 2,7 2,9 2,2 2,5 3,5 1,5 2,5 1,9

Designation: C 581 – 03 An American National Standard

Standard Practice forDetermining Chemical Resistance of Thermosetting ResinsUsed in Glass-Fiber-Reinforced Structures Intended forLiquid Service 1

This standard is issued under the fixed designation C 581; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice is designed to evaluate, in an unstressedstate, the chemical resistance of thermosetting resins used inthe fabrication of reinforced thermosetting plastic (RTP) lami-nates. This practice provides for the determination of changesin the properties, described as follows, of the test specimensand test reagent after exposure of the specimens to the reagent:hardness of specimens, weight change thickness, appearance ofspecimens, appearance of immersion media, and flexuralstrength and modulus.

1.2 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses are given forinformation only.

NOTE 1—This practice may also be used to evaluate other factors, suchas surfacing veils, the effect of resin additives, and fabrication variables onthe chemical resistance of the resin.

NOTE 2—There is no similar or equivalent ISO standard.

1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards:D 790 Test Methods for Flexural Properties of Unreinforced

and Reinforced Plastics and Electrical Insulating Materi-als2

D 2563 Practice for Classifying Visual Defects in Glass-Reinforced Plastic Laminate Parts3

D 2583 Test Method for Indentation Hardness of RigidPlastics by Means of a Barcol Impressor3

D 2584 Test Method for Ignition Loss of Cured ReinforcedResins3

3. Significance and Use

3.1 The results obtained by this practice shall serve as aguide in, but not as the sole basis for, selection of a thermo-setting resin used in an RTP structure. No attempt has beenmade to incorporate into the practice all the various factors thatmay enter into the serviceability of an RTP structure whensubjected to chemical environments. These factors may includestress, different resin-to-glass ratios, and multiple veils.

4. Apparatus

4.1 Hardness Testing Instrument—This shall be as de-scribed in Test Method D 2583.

4.2 Flexural Properties Testing Apparatus, in accordancewith Test Methods D 790.

4.3 Thickness Measurement—A micrometer suitable formeasurement to 0.001 in. (0.025 mm).

4.4 Containers, of sufficient size, capacity, and inertness toallow total immersion of reinforced thermosetting plasticspecimens in the specific corrosives chosen for testing. Thesecontainers shall, when necessary, be capable of maintainingliquid levels of volatile solutions, that is, solvents. This can beaccomplished by the use of reflux condensers.

4.5 Heating Apparatus—A constant temperature oven, heat-ing mantle, or liquid bath capable of maintaining temperaturewithin range of64.0°F (62.2°C). Proper precautions shouldbe taken if the corrosives selected are flammable liquids.

4.6 Analytical Balance, suitable for accurate weighing to0.001 g.

5. Reagents

5.1 The test media shall consist of the reagents or solutionsto which the RTP laminates are to be exposed.

6. Test Specimens

6.1 Standard Laminates—Prepare standard fiber-reinforcedlaminates using identical reinforcement in all of the laminates.The laminates shall be constructed of the following materials:

6.1.1 Surfacing Mat (Veil)—A thin mat of fine fibers usedprimarily to produce a smooth, resin-rich surface on a rein-forced plastic. The surfacing veil helps determine the thicknessof the resin-rich layer, reduces microcracking and provides a

1 This practice is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.23 on Reinforced Plastic PipingSystems and Chemical Equipment.

Current edition approved July 10, 2003. Published August 2003. Originallyapproved in 1965. Last previous edition approved in 2000 as C 581 – 00.

2 Annual Book of ASTM Standards, Vol 08.01.3 Annual Book of ASTM Standards, Vol 08.02.

1

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.

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Praktik ini memberikan penentuan perubahan di properti, dijelaskan sebagai berikut, dari spesimen uji dan uji reagen setelah terpapar spesimen ke pereaksi: kekerasan spesimen, ketebalan perubahan berat, penampilan spesimen, tampilan media perendaman, dan lentur kekuatan dan modulus.

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non-wicking chemically–resistant layer. The surfacing veilshall be compatible with the resin, and manufactured withuniform fiber distribution and non-bundled fibers. The dry veillayer(s) shall be a minimum 10 mils in thickness and producea 10 to 15 mil resin-saturated veil layer per 10 mils of dry veil.To eliminate the surfacing veil as a variable in corrosion tests,prepare each laminate within a test group with the samesurfacing veil.

6.1.2 Chopped Strand Mat—Type E glass fiber with sizingand binder compatible with the resin. Other glass fiber com-positions may be used but should be considered as variables forcomparison to the standard.

6.1.3 Resin—Catalyzed and promoted in accordance withthe resin manufacturer’s recommendation.

NOTE 3—Fillers, such as antimony trioxide for improved fire retardancyor thixotropes for viscosity control, may be added, but may detract fromthe corrosion resistance of the test laminate.

6.2 Dimensions and General Properties—The laminatesshall conform to the required dimensions and general proper-ties of 6.2 and be fabricated in accordance with 6.3.

6.2.1 Laminate Size—A suitable laminate size has beenfound to be 26 by 33 in. (660 by 838 mm) after trimming. Thislaminate size is not restrictive and other dimensions may beused.

6.2.2 Thickness—The thickness of the cured standard lami-nate shall be between 0.120 and 0.140 in. (3.05 and 3.56 mm).

6.2.3 Reinforcement Content—The glass fiber and bindershall be 4.736 0.47 oz/ft2(three layers of 1.5 oz/ft2 choppedstrand mat 4.5 oz/ft2 having a nominal binder content of 3.5 %and two layers of 10 mil surfacing mat 0.23 oz/ft2 having anominal binder content of 7 %)—determined by preweighingthe materials prior to construction of the laminate. This isequivalent to 23.6 weight % (12.5 volume %) glass fiber whenusing a resin having a cured specific gravity of 1.15. Such alaminate will have a thickness of 0.125 in. (3.18 mm). The useof resins having different specific gravities will result indifferent weight percentages of glass fiber, but the volumepercentage of glass fiber will remain the same. When usingsynthetic organic fiber surfacing veil, the glass content shall be4.506 0.45 oz/ft2( three layers of 1.5oz/ft2 chopped strand mathaving a nominal binder content of 3.5 %).

6.2.4 Hardness—The hardness shall be at least 90 % of thatof a fully-cured clear casting of the resin, or of a similarlyconstructed laminate as defined by the resin manufacturer.Hardness shall be determined in accordance with s4.1. Itshould be noted that the use of synthetic veil will result insignificantly lower hardness values. The hardness value willvary with the type of resin and number of plies of syntheticveil. The resin manufacturer should be contacted for theallowable Barcol hardness value of a laminate containingsynthetic veils with the specific resin.

6.2.5 Laminate Condition—The laminate shall meet Accep-tance Level I of Table I of Practice D 2563.

6.3 Fabrication of Standard Laminate—The sequence oflay-up shall be as follows:

6.3.1 Apply catalyzed resin and a 10-mil (0.25-mm) surfac-ing mat on a flat surface covered with plastic release film4 ortreated with a suitable release agent and roll to distribute resin.

NOTE 4—The following formula may be used as a guide to determinethe total weight of resin to be used. This is equivalent to 12.5 volume %glass fiber in the laminate. Grams resin equals grams glass fiber materialper 6.2.3 times 2.82G. WhereG equals specific gravity of cured resin.Excess resin may be used due to loss by adhering to mixing containers,rollers, and other factors. A suggested amount of excess resin is 10 to 15 %by weight.

6.3.2 Follow with three plies of 1.5 oz/ft2 chopped strandmat and resin. Roll after each ply to distribute and wet-out thechopped strand mat. Rolling with a serrated roller may be doneafter each ply to remove entrapped air but shall be done inaccordance with 6.3.4. The mat weight shall be within65 % of1.5 oz/ft2 upon weighing the full 26 by 33-in. cut (660 by838-mm) piece, (or other full dimension used, 6.2.1.).

NOTE 5—Chopped strand mat should be cut so that the 26-in. dimen-sion is across the width of the roll and the 33-in. dimension is along themachine direction of the mat. Mat weight variation will most commonlyoccur across the width of the mat. If a wide roll of mat, 52 in. (1320 mm)or greater, is used, the two plies of mat should be placed in the laminatesuch that the center cut of one ply is placed over the outside edge of thesecond ply. If narrower width mat is used, the second ply should bereversed 180° in the machine direction and laid on top of the first ply tominimize weight variations.

6.3.3 Follow with a 10-mil (0.25-mm) surfacing mat as in6.3.1.

6.3.4 Remove the air by rolling over the surface with aserrated metal or plastic roller. Take care not to expel enoughresin to raise the glass content above the permissible maxi-mum. The laminate is considered within the range of allowablelevels of resin and glass if the thickness of the laminate iswithin 0.120 and 0.140 in. (3.05 and 3.56 mm), as described in6.2.2.

6.3.5 After the lay-up is completed, cover the laminate witha plastic release film to prevent air inhibition or to provide auniform smooth glossy surface, or both. Carefully smoothdown to remove entrapped air.

NOTE 6—The application of the release film may be accomplished byany convenient method. Regardless of how it is applied, it is critical thatany entrapped air between the film and the laminate be entirely removed.One method of application is done by previously wrapping the film arounda metal rod. Starting at one edge of the laminate, slowly unroll the filmfrom the rod, keeping a bead of resin ahead of the rod as you cross thelaminate. Any entrapped air remaining can be removed by rubbing atongue depressor across the release film surface. Carefully pull the filmtaut and fasten at the edges to prevent wrinkling of the film. Placing stops(neoprene has been found to be suitable) around the edges of the laminateand passing a heavy metal roller over the laminate helps to insure uniformcontrolled thickness.

6.3.6 Cure as recommended by the resin manufacturer. Thecure schedule shall be reported.

6.3.7 Trim edges as required.6.4 Record of Standard Laminate Construction—Record the

properties of the standard laminate as follows:

4 3 to 5 mil standard oriented polyester film (MYLARt—Types A, S, or D, orMELINEXt—Types S, 0, or 442) has been found suitable for this purpose.

C 581 – 03

2

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6.4.1 Hardness—Determine Barcol hardness on the strip asdescribed in 6.2.4 in accordance with Test Method D 2583.

6.4.2 Laminate Conditions—Visually examine the laminate.The laminate shall meet Acceptance Level I of Table 1 ofPractice D 2563.

6.4.3 If the laminate meets the requirements of this speci-fication, retain the laminate sections for preparation of testspecimens.

NOTE 7—The major criteria for accepting a laminate is thickness andnot glass content. If glass content is desired, cut eight 1 by 1 in. specimensfrom the center of the laminate and test in accordance with Test MethodD 2584.

6.5 Individual Test Specimens:6.5.1 Specimens for immersion in test solutions shall be

approximately 4 by 5 in. (101.6 by 127 mm), cut from thestandard laminate.

6.5.2 Identity of specimens shall be maintained by suitablemeans.

6.5.3 Cut edges and drilled holes, if used for suspension,shall be sanded smooth and coated with paraffinated resin.

6.5.4 The number of specimens required is dependent on thenumber of test solutions to be employed, the number ofdifferent temperatures at which testing is performed, and thenumber of test intervals. In addition, at least two 4 by 5 in.(101.6 by 127 mm) specimens shall be available for test (see7.4) following the curing period, prior to immersion.

7. Procedure

7.1 Measurement of Specimens—Immediately following thecuring period, measure the thickness of the specimens to thenearest 0.001 in. (0.025 mm) at the geometric center of each ofthe intended 1 by 3 in. (25.4 by 76.2 mm) specimens that willbe cut for flexural tests after the completed exposures. Measurethe weight of the specimens to the nearest 0.01 g. Thesethickness and weight measurements shall also be used forcomparison against thickness and weight measurements afterthe completed exposures.

7.2 Exposure—Following the curing period, as specified in6.3.6, prior to immersion, record a brief description of the colorand surface appearance of the coupons and the color and theclarity of the test solution. The total number of coupons percontainer is not limited except by the ability of the container tohold the coupons without touching each other or the container.The coupons must always be completely immersed. Couponsshould be vertical, parallel, and spaced a minimum of 0.25 in.(6.35 mm) apart. There should be a minimum of 0.50 in. (12.7mm) between coupon edges and the container or the liquidsurface. Place the closed container in a constant temperatureoven adjusted to the required temperature or in a suitablyadjusted liquid bath. Examine the coupons after 30, 90, 180days, and one year of immersion or other time intervals asrequired to determine the rate of attack.

7.2.1 Discard the test solution and replace it with freshsolution as often as necessary to maintain original compositionand concentration. As a minimum, solutions known to be stableshould be replaced at the end of each test period.

7.3 Cleaning and Examination After Exposure—Clean thecoupon and dry by blotting with a paper towel. Cold tap water

is normally used for specimen cleaning. If other cleaningagents are used, verify that they do not attack the resin beingtested.

7.3.1 Note any indication of surface attack on a coupon, anydiscoloration of the test solution, and the formation of anysediment.

7.3.2 After final blotting, immediately measure the couponthickness to the nearest 0.001 in. (0.025 mm) in the geometriccenter of each intended 1 by 3 in. (25 by 76.2 mm) specimen.Measure the coupon to the nearest 0.01g. The Barcol hardnesscan then be checked, taking an average of ten readings on eachcoupon, a minimum of 0.50 in. (12.7 mm) from the edge.

7.3.3 After washing and measuring thickness, weight, andBarcol hardness, place the coupons in an air-tight polyethylenebag for conditioning or shipping as described in 7.4.1.

7.4 Flexural Testing—Determine the flexural strength andmodulus for: (1) two sets of three specimens immediatelyfollowing the curing period, and (2) one set of three specimensafter each inspection, for each solution, and each test tempera-ture. Calculation of flexural strength and modulus after expo-sure should use the coupon thickness determined at the time offlexural testing as measured in 7.3.2. The two pretested setsshall be taken from the center of the laminate as described in6.2.1. The flexural strengths for these two sets shall beaveraged together for use in calculating the retained flexuralstrength in 8.2. The flexural modulus values shall also beaveraged for use in 8.2.

7.4.1 Flexural tests shall be conducted in accordance withProcedure A of Test Methods D 790, except for the condition-ing parameters specified in this document. Coupons beingtested at the exposure location shall be placed in the condi-tioning environment for a minimum of 2 h immediatelyfollowing the “cleaning and examination” described in 7.3. Thecoupon shall be tested during the same day after removing thecoupon from the test environment. For testing at a differentlocation, the clean, dry coupons should be placed in a vaportight bag for shipment.

NOTE 8—In cases of volatile chemical exposure, special methods ofspecimen handling may be required.

7.4.2 Three 1 by 3 in. (25 by 76.2 mm) (see Fig. 1) are cutfrom each 4 by 5 in. coupon. After cutting, the specimen edgesshall be routed or sanded to provide a nick-free edge. Testspecimens shall be the full thickness of the exposure coupon.

8. Calculation

8.1 Barcol Hardness Change—Tabulate or construct agraph showing the actual hardness readings of the specimensexposed at a given temperature, and the test period, in days.

8.2 Retained Flexural Strength and Modulus—Calculate tothe nearest 1.0 %, the percentage retention of flexural strengthand flexural modulus of the specimen during immersion foreach examination period, taking the flexural strength andflexural modulus after curing as 100 %:

Retained flexural strength, %5 @S2/S1# 3 100 (1)

where:S1 = flexural strength of specimen after curing period, andS2 = flexural strength of specimen after test period.

C 581 – 03

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Retained flexural modulus, %5 @E2/E1# 3 100 (2)

where:E1 = flexural modulus of specimen after curing period, andE2 = flexural modulus of specimen after test period.

8.2.1 Calculate flexural strength and modulus properties inaccordance with Section 11 of Test Methods D 790.

8.2.2 Construct graphs showing the average percentage ofretained flexural strength and the average flexural modulus ofthe specimens broken at a given examination period afterimmersion in a particular test solution at a given temperature,plotting the percentage of retained flexural strength and flex-ural modulus as the vertical axis, and the test period, in days,as the horizontal axis.

8.3 Percent Weight and Thickness Change—Calculate to thenearest 0.01 % the percent weight and thickness change of thespecimen during immersion for each examination period.

8.4 Calculate the percent weight and thickness change, andtabulate or graph these values as a function of the test period,in days.

9. Interpretation of Results

9.1 Mechanical Properties of the Specimen—Because of thechemical nature of certain types of plastic materials, the rate ofchange with time is of more significance than the actual valueat any one time. A plot of the test results will indicate whethera particular specimen will approach constant flexural strength,flexural modulus, or hardness with time or will continue tochange as the test progresses.

9.2 Appearance of Specimen—Visual inspection of the ex-posed specimen for surface cracks, loss of gloss, etching,blistering, pitting, softening, changes in thickness, or otherirregularities, is very important, for these conditions indicatesome degradation of the laminate by a chemical environment.

9.3 Appearance of Immersion Medium—Discoloration ofthe test solution and the formation of sediment may besignificant factors. An initial discoloration may indicate extrac-tion of soluble components.

9.4 Weight and Thickness of Specimen—Weight and thick-ness changes can indicate the extent of chemical degradation orabsorption of the test solution.

NOTE 9—All test exposures should be carried out for the longestpractical time to assure valid results. It is particularly important to obtain6 and 12-month results in order to determine whether the properties arestable over a period of time. Short-term results (less than six months) canbe unreliable when evaluating resins.

10. Report

10.1 Report the following information:10.1.1 Company and individual preparing standard lami-

nates.10.1.2 Complete identification of material tested including

resin, nonvolatile content, accelerator, catalyst, reinforcement,surfacing mat, and filler, such as fire-retardant additive orthixotropes.

10.1.3 Cure cycle including room temperature gel time,time at room temperature before testing or before post-cure ifrequired, post-cure time, and temperature. Any special post-curing techniques such as boiling water or steam for FDA-typeapplications shall also be reported.

10.1.4 Glass content of standard laminate, if run in accor-dance with Note 7.

10.1.5 Hardness, flexural strength of control coupons.10.1.6 Color and surface appearance of specimens before

testing.10.1.7 Test conditions; immersion medium, temperature,

and the like.10.1.8 Total duration of test in days, and examination

periods, in days. For each examination period, the data listed in10.1.8.11 through 10.1.8.6 are required.

10.1.8.1 Pretesting samples conditioning (if different thanstandard).

10.1.8.2 Appearance of specimens after immersion (surfacecracks, loss of gloss, etching, pitting, softening, and the like).

10.1.8.3 Appearance of immersion medium (discoloration,sediment, and the like).

10.1.8.4 Barcol hardness of the specimens before and afterexposure.

10.1.8.5 Weight and thickness before and after exposure.10.1.8.6 Flexural strength and flexural modulus of coupons

and percent retention of flexural strength and flexural modulus.10.1.9 Graph showing percent retention of flexural strength

and flexural modulus plotted against test periods.

11. Precision and Bias

11.1 No precision statement can be made for this practice,since controlled round-robin test programs have not been run.The test results of this practice are obtained to assign biasstatements to the subjective results since there are no standards.The bias of the quantitative results are covered by TestMethods D 790.

FIG. 1 Specimen Cutting Guide

C 581 – 03

4

12. Keywords

12.1 chemical resistance; glass-fiber-reinforced; glass-reinforced plastic (GRP); laminate; liquid service; reinforcedthermosetting plastic (RTP); reinforced thermosetting resins;

thermosetting resins

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website(www.astm.org).

C 581 – 03

5

Designation: C 582 – 02 An American National Standard

Standard Specification forContact-Molded Reinforced Thermosetting Plastic (RTP)Laminates for Corrosion-Resistant Equipment 1

This standard is issued under the fixed designation C 582; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This specification covers composition, thickness, fabri-cating procedures, and physical property requirements for glassfiber reinforced thermoset polyester, vinyl ester, or otherqualified thermosetting resin laminates comprising the materi-als of construction for RTP corrosion-resistant tanks, piping,and equipment. This specification is limited to fabrication bycontact molding.

NOTE 1—The laminates covered by this specification are manufacturedduring fabrication of contact-molded RTP tanks, piping, and otherequipment.

NOTE 2—There is no similar or equivalent ISO standard.

1.2 The following safety hazards caveat pertains only to thetest method portion, Section 8, of this specification:Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.


2.1 ASTM Standards:C 581 Practice for Determining Chemical Resistance of

Thermosetting Resins Used in Glass Fiber ReinforcedStructures Intended for Liquid Service2

D 638 Test Method for Tensile Properties of Plastics3

D 695 Test Method for Compressive Properties of RigidPlastics3

D 790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-als3

D 883 Terminology Relating to Plastics3

D 2583 Test Method for Indentation Hardness of RigidPlastics by Means of a Barcol Impressor4

D 2584 Test Method for Ignition Loss of Cured ReinforcedResins4

D 3681 Test Method for Chemical Resistance of “Fiber-glass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipein a Deflected Condition2

E 84 Test Method for Surface Burning Characteristics ofBuilding Materials5

3. Definitions

3.1 Definitions used in this specification are in accordancewith Terminology D 883 unless otherwise indicated. Theabbreviation for reinforced thermoset plastic is RTP.

3.2 polyester—resins produced by the polycondensation ofdihydroxyderivatives and dibasic organic acids or anhydrides,wherein at least one component contributes ethylenic unsat-uration yielding resins that can be compounded with styrylmonomers and reacted to give highly crosslinked thermosetcopolymers.

3.3 vinyl ester—resins characterized by reactive unsatura-tion located predominately in terminal positions that can becompounded with styryl monomers and reacted to give highlycrosslinked thermoset copolymers.

NOTE 3—These resins are handled in the same way as polyesters infabrication of RTP components.

3.4 contact molding—a method of fabrication wherein theglass-fiber reinforcement is applied to the mold, in the form ofchopped strand mat or woven roving, by hand or from a reel,or in the form of chopped strands of continuous-filament glassfrom a chopper-spray gun. The resin matrix is applied byvarious methods, including brush, roller, or spray gun. Con-solidation of the composite laminate is by rolling.

4. Classification

4.1 Laminates shall be classified according to type, class,and grade.

4.1.1 Type—In Roman numerals, shall designate the rein-forcement structure comprised of specific plies of glass fiber inspecific sequences.

4.1.1.1 Type I—A standard all-mat or chopped-roving con-struction, or both, as shown in Table 1.

1 This specification is under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.23 on ReinforcedPlastic Piping Systems and Chemical Equipment.

Current edition approved Nov. 10, 2002. Published January 2003. Originallyapproved in 1965. Last previous edition approved in 1995 as C 582 – 95.

2 Annual Book of ASTM Standards, Vol 08.04.3 Annual Book of ASTM Standards, Vol 08.01.4 Annual Book of ASTM Standards, Vol 08.02. 5 Annual Book of ASTM Standards, Vol 04.07.

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4.1.1.2 Type II—A standard mat or chopped-roving andwoven-roving construction, or combination thereof, as shownin Table 2.

4.1.1.3 Other types, such as standard mat or chopped rovingwith alternating layers of nonwoven biaxial or unidirectionalreinforcement in the structured plies. may be qualified inaccordance with Appendix X2.

4.1.2 Class—In capital letters, shall designate the genericresin: “P” for polyester and “V” for vinyl ester. The letters“FS” followed by parenthesis, “FS( ),” shall designate fireretardancy, if specified, with maximum flame spread in theparentheses in accordance with Test Method E 84.

NOTE 4—Fire retardancy by Test Method E 84 is determined for0.125-in. (3.175-mm) thick, flat laminates with all-mat glass content of 25to 30 %.

NOTE 5—Maximum flame spread designation by Test Method E 84relates to measurement and description of the properties of materials,products, or systems in response to heat and flame under controlledlaboratory conditions and should not be considered or used for thedescription or appraisal of the fire hazard of materials, products, orsystems under actual fire conditions. However, results of this test may beused as elements of a fire risk assessment that takes into account all thefactors that are pertinent to an assessment of the fire hazard or a particularend use.

TABLE 1 Standard Laminate Composition Type I A

CalculatedThicknessBC

CorrosionBarrierD

Structural PliesE

Number and Sequence of PliesDraftingSymbols

in. (mm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

0.18 (4.6) V M M M M V, 4M0.23 (5.8) V M M M M M V, 5M0.27 (6.9) V M M M M M M V, 6M0.31 (7.9) V M M M M M M M V, 7M0.35 (8.9) V M M M M M M M M V, 8M0.40 (10.2) V M M M M M M M M M V, 9M0.44 (11.2) V M M M M M M M M M M V, 10M0.48 (12.2) V M M M M M M M M M M M V, 11M0.53 (13.5) V M M M M M M M M M M M M V, 12M0.57 (14.5) V M M M M M M M M M M M M M V, 13M0.61 (15.5) V M M M M M M M M M M M M M M V, 14M0.66 (16.8) V M M M M M M M M M M M M M M M V, 15M0.70 (17.8) V M M M M M M M M M M M M M M M M V, 16M0.74 (18.8) V M M M M M M M M M M M M M M M M M V, 17M

A Glass content, weight, % = 25 to 30, all thickness.B Calculated thickness for design purposes is determined as follows:

V = Surfacing mat − 0.010 in./ply (0.25 mm/ply) when saturated with resin.M = 1 1 / 2 oz/ft2 (459 g/m2) mat − 0.043 in./ply (1.1 mm/ply) when saturated with resin.

C The thickness shall be not less than 90 % of the calculated thickness shown.D Corrosion barrier (Plies 1, 2, and 3) shall gel before structural plies are added.E Structural lay-up may be interrupted at intervals long enough to exotherm if required by the laminate manufacturing procedure and 6.3.1.

TABLE 2 Standard Laminate Composition Type II

CalculatedThicknessAB

GlassContent(weight,

%)

CorrosionBarrierC

Structural PliesD

Number and Sequence of Plies DraftingSymbols

in. (mm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

0.22 (5.6) 28 to 33 V M M M R M V, 2M, MRM0.29 (7.4) 30 to 35 V M M M R M R M V, 2M, 2(MR)M0.37 (9.4) 30 to 35 V M M M R M R M R M V, 2M, 3(MR)M0.41 (10.4) 30 to 35 V M M M R M R M R M M V, 2M, 3(MR)M,

M0.49 (12.5) 34 to 38 V M M M R M R M R M M R M V, 2M, 3(MR)M,

MRM0.57 (14.5) 34 to 38 V M M M R M R M R M M R M R M V, 2M, 3(MR)M,

2(MR)M0.64 (16.3) 37 to 41 V M M M R M R M R M M R M R M R M V, 2M, 3(MR)M,

3(MR)M0.69 (17.5) 37 to 41 V M M M R M R M R M M R M R M R M M V, 2M, 3(MR)M,

3(MR)M,M0.76 (19.3) 37 to 41 V M M M R M R M R M M R M R M R M M R M V, 2M, 3(MR)M,

3(MR)M,MRM

A Calculated thickness for design purposes is determined as follows:V = Surfacing mat − 0.010 in./ply (0.25 mm/ply) when saturated with resin.M = 1 1 / 2 oz/ft2 (459 g/m2) mat = 0.043 in./ply (1.1 mm/ply) when saturated with resin.R = 24 1 / 2 oz/yd2 (832 g/m2) 5 3 4 woven roving = 0.033 in./ply (0.84 mm/ply) when saturated with resin.

B The thickness shall be not less than 90 % of the calculated thickness shown.C Corrosion barrier (Plies 1, 2, and 3) shall gel before structural plies are added.D Structural lay-up may be interrupted long enough to exotherm following an “M” ply, if required by the laminate manufacturing procedure. Location of exotherm plies

may be shifted within the laminate body. No plies may be omitted. Refer to 6.3.1.

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4.1.3 Grade—In Arabic numerals, shall designate the mini-mum physical property levels of a laminate at 73.46 3.6°F (236 2°C).

NOTE 6—The five Arabic grade numbers designate minimum physicalproperty levels of a laminate obtained from tests of representativeproduction process samples. They are not arbitrarily selected values.

4.1.4 Thickness—Nominal, shall be designated by Arabicnumber in decimal hundredths of an inch. (See Table 1 andTable 2 for standard thicknesses.)

NOTE 7—Table 1 and Table 2 are for reference purposes and do notpreclude other laminate-type constructions, such as nonwoven biaxial orunidirectional fabric, which may be agreed upon between the buyer andthe seller, or may be added to this specification if they have been fullyidentified and characterized, as shown in Appendix X2.

4.1.5 Classification Requirements for Different Laminates—Laminate designation from Table 3 shall consist of the abbre-viation RTP followed by (1) type in Roman numerals; (2) classin capital letters followed by FS( ) if required; (3) gradeconsisting of five Arabic numbers to designate minimum levelsof physical properties and (4) thickness designated by Arabicnumber in decimal inches (or ALL, if properties apply to allthicknesses).

4.1.5.1 Examples:(1) RTP I P 13211 ALL, designates Type I polyester

laminate, non-fire-retardant Grade 13211, having the followingminimum physical property levels (see Table 3):

Tensile strength, ultimate—9000 psi (62 MPa).Tensile modulus—1 050 000 psi (7242 MPa).Flexural strength, ultimate—18 000 psi (124 MPa).Flexural modulus—700 000 psi (4828 MPa).Glass content—25 %.Thickness—“ALL” thicknesses.

(2) RTP II P FS(25) 55433.30, designates Type II,polyester fire-retardant resin laminate with a maximum flamespread of 25, Grade 55433 having the following minimum

physical property levels (see Table 3):Tensile strength, ultimate—17 500 psi (121 MPa).Tensile modulus—1 300 000 psi (8966 MPa).Flexural strength, ultimate—22 000 psi (152 MPa).Flexural modulus—1 000 000 psi (6897 MPa).Glass content—30 %.Thickness—0.30 in. (7.62 mm).

5. Materials

5.1 Resin Matrix System:5.1.1 The resin shall be determined to be acceptable for the

service either by test, see 8.6, or by verified case history.5.1.2 Catalyst/Promoter System, shall be as recommended

or approved by the resin producer.5.1.3 Diluents, such as added styrene, fillers, dyes, pig-

ments, or flame retardants shall be used only when agreed uponbetween the fabricator and the buyer. When such items arerequired, limits for each shall be agreed upon between thefabricator and the buyer. A thixotropic agent may be added tothe resin for viscosity control.

NOTE 8—The addition of fillers, dyes, pigments, flame retardants, andthixotropic agents may interfere with visual inspection of laminate quality.

NOTE 9—Chemical resistance can be significantly affected by thecatalyst/promoter system, diluents, dyes, fillers, flame retardants, orthixotropic agent used in the resin.

5.1.4 Resin Pastes, used where necessary to fill crevicesformed by joining subassemblies before overlay shall not besubject to the limitations of 5.1.3. Pastes shall be made withthixotropic agents.

5.1.5 Ultraviolet Absorbers, may be added to the exteriorsurface for improved weather resistance when agreed uponbetween the fabricator and the buyer.

5.2 Fiber Reinforcement:5.2.1 Surfacing Mat (veil)is a thin mat of fine fibers used

primarily to produce a smooth surface on a reinforced plastic.

TABLE 3 Classification System for Hand Lay-up Laminates Using Minimum Property Values A

Classification Order

RTP followed by:

(1) Type I II III IV V(2) Class P

PolyesterVVinylester

. . . . . . . . . followed by FS ( ), ifspecified with flamespread in parentheses inaccordance with TestMethod E 84

Physical and Mechanical Properties(3) Grade 1 2 3 4 5 6 7 8 9 01st Digit: Tensile strength, 9 11 13 15 17.5 20 . . . . . . . . . . . .

ultimate psi 3 103

(MPa) (62) (76) (90) (104) (121) (138) . . . . . . . . . . . .2nd Digit: Tensile modulus, 0.85 0.95 1.05 1.15 1.3 1.5 1.75 2.0 . . . . . .

tangent psi 3 103

(MPa) (5 863) (6 552) (7 242) (7 932) (8 966) (10 346) (12 070) (13 794) . . . . . .3rd Digit: Flexural strength, 16 18 20 22 24 . . . . . . . . . . . . . . .

ultimate psi 3 103

(MPa) (110) (124) (138) (152) (166) . . . . . . . . . . . . . . .4th Digit: Flexural modulus, 0.7 0.85 1.0 1.15 1.3 1.5 . . . . . . . . . . . .

psi 3 106

(MPa) (4 828) (5 863) (6 897) (7 932) (8 966) (10 346) . . . . . . . . . . . .5th Digit: Glass content, by 25 28 30 34 37 40 44 . . . . . . . . .

weight, %A Table will be completed as new resins and higher strength laminates become available.

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5.2.1.1 Veil shall be determined to be acceptable for theservice either by Test Methods C 581 or D 3681, or by averified case history.

5.2.1.2 Requirements of acceptable surface veils are:(a) Resin compatibility,(b) Uniform fiber distribution,(c) Single filaments (not bundled),(d) The thickness shall be a minimum of 10 mils per ply

when saturated with resin, and(e) Minimum fiber length shall be 0.5 in.

NOTE 10—The chemical resistance of the RTP laminate is provided bythe resin. In combination with the cured resin, the surfacing veil helpsdetermine the thickness of the resin-rich layer, reduces microcracking, andprovides a nonwicking chemically resistant layer.

Additional desirable considerations in choosing a veil for a specificapplication include:

(a) Drapability (surfacing veil should conform to mold shape),

(b) Dry and wet tensile strength,

(c) Binder solubility (if used),

(d) Wetability,

(e) Surfacing veil shall wet-out completely without trapping air duringlaminating, and

(f) Surfacing veil should not inhibit resin cure.

5.2.2 Chopped-Strand Mat, shall be “E” or “ECR” typeglass fiber, 11⁄2 oz/ft2 (459 g/m2), with sizing and bindercompatible with the resin.

5.2.3 Woven Roving, shall be “E” or “ECR” type glass, 241⁄2oz/yd2 (832 g/m2), 5 by 4 square weave fabric having a sizingcompatible with the resin.

5.2.4 Roving, used in chopper guns for spray-up application,shall be “E” or “ECR” type glass with sizing compatible withthe resin.

5.2.5 Other Reinforcements, such as nonwoven biaxial orunidirectional fabric. These products shall be a commercialgrade of “E” or “ECR” type glass fiber with a sizing that iscompatible with the resin.

5.3 Laminates:5.3.1 Laminate construction shall be in accordance with the

tabulated lay-up sequence for the specified type.5.3.2 Type I, laminate structure is detailed in Table 1.5.3.3 Type II, laminate structure is detailed in Table 2.

6. Laminate Fabrication

6.1 Apply the catalyzed resin to a mold or mandrel properlyprepared with a parting agent or film suitable for the lay-upresin. Next apply the specified surface mat, rolling so as todraw the resin through the mat for thorough wet-out anddeaeration.

6.2 Apply resin and two plies of 11⁄2-oz (42.6-g) mat. As analternative, a minimum of two passes of chopped roving(minimum fiber length 1 in. (25.4 mm) and resin may beapplied by the spray-up process equivalent in weight andthickness to 3 oz/ft2 (918 g/m2) of chopped mat. Each pass ofchopped roving or ply of chopped-strand mat shall be thor-oughly rolled out. This section of the laminate shall be allowedto exotherm prior to application of subsequent plies of rein-forcement.

6.3 Continue lay-up in the sequence of plies, tabulated forthe specified laminate type. Roll each ply for thorough wet-outand deaeration.

6.3.1 Interruption of laminate construction for exothermshall follow instructions noted on Table 1 and Table 2 for theparticular laminate type. The final ply of reinforcement beforeinterruption for exotherm shall be 11⁄2-oz/ft2 (459-g/m2) mat orchopped roving equivalent. The initial ply of the followinglamination shall be 11⁄2-oz/ft2 mat or chopped roving equiva-lent.

6.4 The outer surface of the fabricated laminate shall besmooth and free of exposed glass fibers. The final ply shall bemat or chopped roving equivalent. A surfacing mat is notrequired unless specified. Surface resin may require the addi-tion of paraffin or may be sealed with overlaid film, as requiredor approved by the resin producer, to ensure proper surfacecure.

6.4.1 When pigmentation is specified, the pigment shall beincorporated only in the resin used to lay-up the final laminateply.

6.5 All edges of reinforcement material except surfacingmat shall be lapped 1-in. (25.4-mm) minimum. Lapped edgesof adjacent layers shall be staggered. Surfacing mat shall bebutted together or have overlaps no more than1⁄2 in. (12.7 mm).Gaps are not permitted.

7. Physical and Mechanical Properties

7.1 The composition and sequence requirements for Type Iand II laminates are shown in Table 1 and Table 2.

7.2 The mechanical property requirements for Type I and IIlaminates are shown in Table 4.

7.3 Physical properties of each type and grade of laminateshall be established on flat laminates prepared under shopconditions. In Type II laminates the woven roving is to be laidsquare, and test specimens are to be cut parallel to the warprovings.

7.3.1 Test specimens cut from fabricated equipment usuallyare not parallel to warp rovings. Interpretation of mechanicalproperty data obtained from such specimens is discussed inAppendix X1.

8. Test Methods

8.1 Tensile Strength and Tangent Modulus of Elasticity—Test Method D 638.

8.1.1 Specimens shall be in accordance with Type III, Fig. 1of Test Method D 638 for all laminate thicknesses.

8.2 Flexural Strength and Tangent Modulus of Elasticity—Test Methods D 790, Method I, Procedure A, and Table 1, 1/d= 16 to 1.

8.2.1 Specimens shall be the full thickness of the laminateas fabricated.

8.2.2 The loading nose shall be applied to the inner face ofthe laminate specimen.

8.3 Glass Content—Test Method D 2584.8.3.1 The residual, undisturbed glass-fiber plies from the

ignition shall be separated carefully and counted to confirmstandard lay-up sequence.

8.4 Thicknessshall be measured with a ball-foot microme-ter.

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8.5 Hardness—Test Method D 2583.8.6 Chemical Resistance—Test Method C 581.8.6.1 Exposure tests under plant operating conditions shall

employ Test Method C 581 standard test laminate samples.

NOTE 11—Thicker laminates shall not be used for such tests, as resultswill vary significantly compared to exposure of standard samples in TestMethod C 581.

8.7 Surface Flame-Spread Classification—Test MethodE 84.

9. Workmanship and Finish

9.1 The finished laminate shall conform to visual accep-tance criteria of Table 5.

TABLE 4 Standard Laminate Properties

Calculated Thickness,A

in. (mm)Type

TensileB Mechanical Properties, min, psi (MPa)C

Ultimate Stress 310−3 (MPa)

Modulus 3 10−6

(MPa)FlexuralD Edge CompressionE

Ultimate Stress 310−3 (MPa)

Modulus 3 10−6

(MPa)Ultimate Stress 3

10−3 (MPa)

ALL I 9.0 0.85 16.0 0.7 16(62) (5862) (110) (4828) (110)

0.22 (5.6) II 12.0 0.9 19.0 0.8 16(83) (6207) (131) (5518) (110)

0.30 (7.6) II 13.5 1.1 20.0 0.9 18(93) (7587) (138) (6207) (124)

0.37 (9.4) and up II 15.0 1.2 22.0 1.0 20(104) (8276) (152) (6897) (138)

A The thickness shall be not less than 90 % of the calculated thickness shown.B Test Method D 638.C Barcol hardness should be 90 % (minimum) of cast resin hardness.D Test Method D 790.E Test Method D 695.

TABLE 5 Visual Acceptance Criteria

Visual Observation Surface Inspected

Process Side Nonprocess Side

Cracks None NoneCrazing (fine resin-rich surface cracks) None Maximum dimension 1 in. (25.4 mm). Maximum density

5/ft2 (0.1 m2).A

Blisters (rounded elevations of thelaminate surface over bubbles)

None Maximum 1 / 4 -in. (6.4-mm) diameter by 1 / 8 in. (3.2mm) high. Maximum 2/ft2 (2/0.1 m2).A

Wrinkles and solid blisters Maximum deviation, 20 % of wall thickness, but not exceeding1 / 8 in. (3.2 mm).A

Maximum deviation, 20 % of wall thickness, but notexceeding 3 / 16 in. (4.8 mm).A

Pits (craters in the laminate surface) Maximum dimensions, 1 / 8 -in. (3.2-mm) diameter by 1 / 32in. (0.8 mm) deep. Maximum number 10/ft2 (10/0.1 mm2).A

Maximum dimension 1 / 8 -in. (3.2-mm) diameter by1 / 16 in. (1.6 mm) deep. Maximum density 10/ft2 (10/0.1 m2).A

Surface porosity, pin holes, or pores inthe laminate

Maximum dimensions, 1 / 16 -in. (1.6-mm) diameter by 1 / 32in. (0.8 mm) deep. Maximum number 20/ft2 (20/0.1 m2) by1 / 16 in. (1.6 mm). Must be resin-rich.A

Maximum dimension 1 / 16 -in. (1.6-mm) diameter by1 / 16 in. deep. Maximum number 20/ft2 (20/0.1 m2).Must be resin-rich.A

Chips (small piece broken from edge orsurface)

Maximum dimensions, 1 / 8 -in. (3.2-mm) diameter by 1 / 32 in.(0.8 mm) deep. Maximum number 1/ft2 (1/0.1 m2).A

Maximum dimension 1 / 4 -in. (6.4-mm) diameter by1 / 16 in. (1.6 mm) deep. Maximum number 5/ft2 (5/0.1m2).A

Dry spot (non-wetted reinforcing) None Maximum dimensions 2 in.2 (13 cm2) per ft2 (0.1 m2).A

Entrapped air (bubbles or voids ordelaminations in the laminate)

Maximum diameter 1 / 16 in. (1.6 mm), 10/in.2 (10/6.5 cm2)maximum density. Maximum diameter 1 / 8 in. (3.2 mm), 2/in.2

(2/6.5 cm2) maximum density. Maximum depth of 1 / 32 in. (0.8mm).AB

Maximum diameter 1 / 16 in. (1.6 mm). 10/in.2 (10/6.5cm2) maximum density. Maximum diameter 1 / 8 in. (3.2mm), 2/in.2 (2/6.5 cm2) maximum density. Maximumdiameter 3 / 16 in. (4.8 mm), 2/ft2 (2/0.1 m2). Maximumdensity.AB

Exposed glass None NoneBurned areas None NoneExposure of cut edges NoneC NoneC

Scratches None over 0.005 in. deep and 4 in. long Maximum length 12 in. (3.5 mm). Maximum depth 0.010in. (0.25 mm) 2/ft2 (2/0.1 m2), maximum density.A

Foreign matter None 1 / 8 -in. (3.2-mm) diameter, maximum density 1/ft2 (1/0.1m2). 3 / 16 -in. (4.8-mm) diameter, maximum density1/ft2 (1/0.1 m2).AD

A Maximum 5 % of total surface area affected.B Entrapped air or bubbles described are allowed, provided the surface cannot easily be broken with a pointed object, such as a knife blade.CCut edges must be covered with resin.D Foreign matter must not penetrate the surface and must not contribute to entrapped air or other defects not allowed.

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9.2 The surface exposed to the chemical environment (pro-cess side) shall be smooth, resin-rich, and fully cured. Theexterior surface shall also be fully cured.

9.2.1 The degree of cure shall be measured by a Barcolhardness test in accordance with Test Method D 2583. At least80 % of the random readings shall exceed at least 90 % of theresin manufacturer’s recommended hardness for the curedresin.

9.2.2 Potential air-inhibited, undercured surfaces (both in-terior secondary lamination and exterior non-mold surfaces)

shall be tested using an acetone sensitivity test. Four to fivedrops of acetone rubbed with a finger on the laminate surface,free of mold release, wax, dust, or dirt, until it evaporates, willnot result in surface softness or tackiness.

10. Keywords

10.1 contact molded; corrosion-resistant equipment; glass-fiber-reinforced; laminate; reinforced thermosetting plastic(RTP); thermoset polyester resin; thermoset vinyl ester resin

APPENDIXES

(Nonmandatory Information)

X1. INTERPRETATION OF DATA FROM ANISOTROPIC LAMINATES

X1.1 General—Mechanical properties of laminates con-taining alternative plies of woven roving and chopped strandmat are dependent upon relationship between the direction of

the applied load and the direction of the roving strands. For 5by 4 square weave roving, the approximate relationship isshown in Fig. X1.1.

StandardDeviation

Note: At 45°, Tensile strength is 69 % of 0°. 11 %Tensile modulus is 86 % of 0°. 2 %

At 45°, Flexural strength is 62 % of 0°. 14 %Flexural modulus is 72 % of 0°. 14 %

At 45°, Composition strength is 100 % of 0°. 11 %Composition modulus is 73 % of 0°. 20 %

FIG. X1.1 Directional Properties of RTP Alternating Mat/WovenRoving

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X2. QUALIFICATION OF LAMINATE STRUCTURE FOR TYPE, CLASS, AND GRADE DESIGNATION

X2.1 General—The RTP laminate structures other thanthose covered by this specification may be characterized fordesignation as standard type, class, and grade by means of thefollowing procedure.

X2.2 Laminate Preparation:

X2.2.1 Under shop fabrication conditions, lay up 12 by25-in. (305 by 635-mm) flat laminates of the proposed laminatestructure in nominal thicknesses of3⁄16 , 5⁄16 , 1⁄2 , and 3⁄4 in.(4.8, 8, 12.8, and 19.2 mm).

X2.2.1.1 Orientation of reinforcing fibers of fabrics shall besuch as to produce maximum properties in the 25-in. (635-mm)direction of the laminate.

X2.2.1.2 Laminates having essentially unidirectional fiberreinforcement shall be 25 by 25-in. (635 by 635-mm) size toprovide sufficient laminate for testing in two directions.

X2.2.1.3 The degree of cure of the surface exposed to thechemical environment (process side) shall be measured by aBarcol hardness test in accordance with Test Method D 2583.At least 80 % of the random readings shall exceed at least 90 %of the resin manufacturer’s recommended hardness for thecured resin.

X2.2.1.4 Cured laminates shall be flat within the limits of1⁄8-in./ft (3.2-mm/0.1 m2) deviation from a plane surface.

X2.3 Testing:

X2.3.1 Tests shall be performed, and results certified, by arecognized independent testing laboratory experienced in thetesting of RTP laminates.

X2.3.2 Determine mechanical and physical properties asrequired by Sections 7 and 8 of this specification.

X2.3.2.1 Unidirectional laminates, as described inX 2.2.1.2, shall have properties determined both parallel to,and at 90° to, the direction of reinforcement.

X2.4 Report:

X2.4.1 The report shall describe laminate manufacture, dateof manufacture, resin used with batch number noted, identifi-cation of reinforcements used, cure components, additives, andall pertinent cure information.

X2.4.2 The report shall contain the data obtained on allspecimens, the laboratory that performed the tests, and the dateperformed.




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Designation: G 31 – 72 (Reapproved 2004)

Standard Practice forLaboratory Immersion Corrosion Testing of Metals 1

This standard is issued under the fixed designation G 31; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice2 describes accepted procedures for andfactors that influence laboratory immersion corrosion tests,particularly mass loss tests. These factors include specimenpreparation, apparatus, test conditions, methods of cleaningspecimens, evaluation of results, and calculation and reportingof corrosion rates. This practice also emphasizes the impor-tance of recording all pertinent data and provides a checklistfor reporting test data. Other ASTM procedures for laboratorycorrosion tests are tabulated in the Appendix. (Warning— Inmany cases the corrosion product on the reactive metalstitanium and zirconium is a hard and tightly bonded oxide thatdefies removal by chemical or ordinary mechanical means. Inmany such cases, corrosion rates are established by mass gainrather than mass loss.)

1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.

1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.


2.1 ASTM Standards:3

A 262 Practices for Detecting Susceptibility to Intergranu-lar Attack in Austenitic Stainless Steels

E 8 Test Methods for Tension Testing of Metallic MaterialsG 1 Practice for Preparing, Cleaning, and Evaluating Cor-

rosion Test SpecimensG 4 Guide for Conducting Corrosion Coupon Tests in Field

Applications

G 16 Guide for Applying Statistics to Analysis of CorrosionData

G 46 Guide for Examination and Evaluation of PittingCorrosion

3. Significance and Use

3.1 Corrosion testing by its very nature precludes completestandardization. This practice, rather than a standardized pro-cedure, is presented as a guide so that some of the pitfalls ofsuch testing may be avoided.

3.2 Experience has shown that all metals and alloys do notrespond alike to the many factors that affect corrosion and that“accelerated” corrosion tests give indicative results only, ormay even be entirely misleading. It is impractical to propose aninflexible standard laboratory corrosion testing procedure forgeneral use, except for material qualification tests wherestandardization is obviously required.

3.3 In designing any corrosion test, consideration must begiven to the various factors discussed in this practice, becausethese factors have been found to affect greatly the resultsobtained.

4. Interferences

4.1 The methods and procedures described herein representthe best current practices for conducting laboratory corrosiontests as developed by corrosion specialists in the processindustries. For proper interpretation of the results obtained, thespecific influence of certain variables must be considered.These include:

4.1.1 Metal specimens immersed in a specific hot liquidmay not corrode at the same rate or in the same manner as inequipment where the metal acts as a heat transfer medium inheating or cooling the liquid. If the influence of heat transfereffects is specifically of interest, specialized procedures (inwhich the corrosion specimen serves as a heat transfer agent)must be employed (1).4

4.1.2 In laboratory tests, the velocity of the environmentrelative to the specimens will normally be determined byconvection currents or the effects induced by aeration orboiling or both. If the specific effects of high velocity are to bestudied, special techniques must be employed to transfer the

1 This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.

Current edition approved May 1, 2004. Published May 2004. Originallyapproved in 1972. Last previous edition approved in 1998 as G 31 – 72 (1998).

2 This practice is based upon NACE Standard TM-01-69, “Test Method-Laboratory Corrosion Testing of Metals for the Process Industries,” with modifica-tions to relate more directly to Practices G 1 and G 31 and Guide G 4.

3 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at [email protected]. ForAnnual Book of ASTMStandardsvolume information, refer to the standard’s Document Summary page onthe ASTM website.

4 The boldface numbers in parentheses refer to the list of references at the end ofthis practice.

1


environment through tubular specimens or to move it rapidlypast the plane face of a corrosion coupon (2). Alternatively, thecoupon may be rotated through the environment, although it isthen difficult to evaluate the velocity quantitatively because ofthe stirring effects incurred.

4.1.3 The behavior of certain metals and alloys may beprofoundly influenced by the presence of dissolved oxygen. Ifthis is a factor to be considered in a specific test, the solutionshould be completely aerated or deaerated in accordance with8.7.

4.1.4 In some cases, the rate of corrosion may be governedby other minor constituents in the solution, in which case theywill have to be continually or intermittently replenished bychanging the solution in the test.

4.1.5 Corrosion products may have undesirable effects on achemical product. The amount of possible contamination canbe estimated from the loss in mass of the specimen, with properapplication of the expected relationships among (1) the area ofcorroding surface, (2) the mass of the chemical producthandled, and (3) the duration of contact of a unit of mass of thechemical product with the corroding surface.

4.1.6 Corrosion products from the coupon may influence thecorrosion rate of the metal itself or of different metals exposedat the same time. For example, the accumulation of cupric ionsin the testing of copper alloys in intermediate strengths ofsulfuric acid will accelerate the corrosion of copper alloys, ascompared to the rates that would be obtained if the corrosionproducts were continually removed. Cupric ions may alsoexhibit a passivating effect upon stainless steel coupons ex-posed at the same time. In practice, only alloys of the samegeneral type should be exposed in the testing apparatus.

4.1.7 Coupon corrosion testing is predominantly designedto investigate general corrosion. There are a number of otherspecial types of phenomena of which one must be aware in thedesign and interpretation of corrosion tests.

4.1.7.1 Galvanic corrosion may be investigated by specialdevices which couple one coupon to another in electricalcontact. The behavior of the specimens in this galvanic coupleare compared with that of insulated specimens exposed on thesame holder and the galvanic effects noted. It should beobserved, however, that galvanic corrosion can be greatlyaffected by the area ratios of the respective metals, the distancebetween the metals and the resistivity of the electrolyte. Thecoupling of corrosion coupons then yields only qualitativeresults, as a particular coupon reflects only the relationshipbetween these two metals at the particular area ratio involved.

4.1.7.2 Crevice corrosion or concentration cell corrosionmay occur where the metal surface is partially blocked fromthe corroding liquid as under a spacer or supporting hook. It isnecessary to evaluate this localized corrosion separately fromthe overall mass loss.

4.1.7.3 Selective corrosion at the grain boundaries (forexample, intergranular corrosion of sensitized austenitic stain-less steels) will not be readily observable in mass lossmeasurements unless the attack is severe enough to cause graindropping, and often requires microscopic examination of thecoupons after exposure.

4.1.7.4 Dealloying or “parting” corrosion is a condition inwhich one constituent is selectively removed from an alloy, asin the dezincification of brass or the graphitization of cast iron.Close attention and a more sophisticated evaluation than asimple mass loss measurement are required to detect thisphenomenon.

4.1.7.5 Certain metals and alloys are subject to a highlylocalized type of attack called pitting corrosion. This cannot beevaluated by mass loss alone. The reporting of nonuniformcorrosion is discussed below. It should be appreciated thatpitting is a statistical phenomenon and that the incidence ofpitting may be directly related to the area of metal exposed. Forexample, a small coupon is not as prone to exhibit pitting as alarge one and it is possible to miss the phenomenon altogetherin the corrosion testing of certain alloys, such as the AISI Type300 series stainless steels in chloride contaminated environ-ments.

4.1.7.6 All metals and alloys are subject to stress-corrosioncracking under some circumstances. This cracking occursunder conditions of applied or residual tensile stress, and itmay or may not be visible to the unaided eye or upon casualinspection. A metallographic examination may confirm thepresence of stress-corrosion cracking. It is imperative to notethat this usually occurs with no significant loss in mass of thetest coupon, although certain refractory metals are an exceptionto these observations. Generally, if cracking is observed on thecoupon, it can be taken as positive indication of susceptibility,whereas failure to effect this phenomenon simply means that itdid not occur under the duration and specific conditions of thetest. Separate and special techniques are employed for thespecific evaluation of the susceptibility of metals and alloys tostress corrosion cracking (see Ref.(3)).

5. Apparatus

5.1 A versatile and convenient apparatus should be used,consisting of a kettle or flask of suitable size (usually 500 to5000 mL), a reflux condenser with atmospheric seal, a spargerfor controlling atmosphere or aeration, a thermowell andtemperature-regulating device, a heating device (mantle, hotplate, or bath), and a specimen support system. If agitation isrequired, the apparatus can be modified to accept a suitablestirring mechanism, such as a magnetic stirrer. A typical resinflask setup for this type test is shown in Fig. 1.

5.2 The suggested components can be modified, simplified,or made more sophisticated to fit the needs of a particularinvestigation. The suggested apparatus is basic and the appa-ratus is limited only by the judgment and ingenuity of theinvestigator.

5.2.1 A glass reaction kettle can be used where the configu-ration and size of the specimen will permit entry through thenarrow kettle neck (for example, 45/50 ground-glass joint). Forsolutions corrosive to glass, suitable metallic or plastic kettlesmay be employed.

5.2.2 In some cases a wide-mouth jar with a suitable closureis sufficient when simple immersion tests at ambient tempera-tures are to be investigated.

5.2.3 Open-beaker tests should not be used because ofevaporation and contamination.

G 31 – 72 (2004)

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5.2.4 In more complex tests, provisions might be needed forcontinuous flow or replenishment of the corrosive liquid, whilesimultaneously maintaining a controlled atmosphere.

6. Sampling

6.1 The bulk sampling of products is outside the scope ofthis practice.

7. Test Specimen

7.1 In laboratory tests, uniform corrosion rates of duplicatespecimens are usually within610 % under the same testconditions. Occasional exceptions, in which a large differenceis observed, can occur under conditions of borderline passivityof metals or alloys that depend on a passive film for theirresistance to corrosion. Therefore, at least duplicate specimensshould normally be exposed in each test.

7.2 If the effects of corrosion are to be determined bychanges in mechanical properties, untested duplicate speci-mens should be preserved in a noncorrosive environment at thesame temperature as the test environment for comparison withthe corroded specimens. The mechanical property commonlyused for comparison is the tensile strength. Measurement ofpercent elongation is a useful index of embrittlement. Theprocedures for determining these values are shown in detail inTest Methods E 8.

7.3 The size and shape of specimens will vary with thepurpose of the test, nature of the materials, and apparatus used.A large surface-to-mass ratio and a small ratio of edge area tototal area are desirable. These ratios can be achieved throughthe use of square or circular specimens of minimum thickness.Masking may also be used to achieve the desired area ratios butmay cause crevice corrosion problems. Circular specimensshould preferably be cut from sheet and not bar stock, tominimize the exposed end grain. Special coupons (for example,sections of welded tubing) may be employed for specificpurposes.

7.3.1 A circular specimen of about 38-mm (1.5-in.) diam-eter is a convenient shape for laboratory corrosion tests. Witha thickness of approximately 3 mm (0.125-in.) and an 8-mm(5⁄16-in.) or 11-mm (7⁄16-in.) diameter hole for mounting, thesespecimens will readily pass through a 45/50 ground-glass jointof a distillation kettle. The total surface area of a circularspecimen is given by the following equation:

A 5 p/2~D 2 2 d 2! 1 tpD 1 tpd (1)

where:t = thickness,D = diameter of the specimen, andd = diameter of the mounting hole.

7.3.1.1 If the hole is completely covered by the mountingsupport, the last term (tpd) in the equation is omitted.

7.3.2 Strip coupons 50 by 25 by 1.6 or 3 mm (2 by 1 by1⁄16

or 1⁄8 in.) may be preferred as corrosion specimens, particularlyif interface or liquid line effects are to be studied by thelaboratory tests (see Fig. 1), but the evaluation of such specificeffects are beyond the scope of this practice.

7.3.3 All specimens should be measured carefully to permitaccurate calculation of the exposed areas. A geometric areacalculation accurate to61 % is usually adequate.

7.4 More uniform results may be expected if a substantiallayer of metal is removed from the specimens to eliminatevariations in condition of the original metallic surface. This canbe done by chemical treatment (pickling), electrolytic removal,or by grinding with a coarse abrasive paper or cloth such as No.50, using care not to work harden the surface (see section 5.7).At least 0.0025 mm (0.0001 in.) or 0.0155 to 0.0233 mg/mm2

(10 to 15 mg/in.2) should be removed. (If clad alloy specimensare to be used, special attention must be given to ensure thatexcessive metal is not removed.) After final preparation of thespecimen surface, the specimens should be stored in a desic-cator until exposure, if they are not used immediately. Inspecial cases (for example, for aluminum and certain copperalloys), a minimum of 24 h storage in a desiccator is recom-mended. The choice of a specific treatment must be consideredon the basis of the alloy to be tested and the reasons for testing.A commercial surface may sometimes yield the most signifi-cant results. Too much surface preparation may remove segre-gated elements, surface contamination, and so forth, andtherefore not be representative.

7.5 Exposure of sheared edges should be avoided unless thepurpose of the test is to study effects of the shearing operation.It may be desirable to test a surface representative of thematerial and metallurgical conditions used in practice.

NOTE 1—The flask can be used as a versatile and convenient apparatusto conduct simple immersion tests. Configuration of top to flask is suchthat more sophisticated apparatus can be added as required by the specifictest being conducted.A = thermowell,B = resin flask,C = specimens hungon supporting device,D = air inlet, E = heating mantle,F = liquid inter-face,G = opening in flask for additional apparatus that may be required,andH = reflux condenser.

FIG. 1 Typical Resin Flask

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7.6 The specimen can be stamped with an appropriateidentifying mark. If metallic contamination of the stamped areamay influence the corrosion behavior, chemical cleaning mustbe employed to remove any traces of foreign particles from thesurface of the coupon (for example, by immersion of stainlesssteel coupons in dilute nitric acid following stamping with steeldies).

7.6.1 The stamp, besides identifying the specimen, intro-duces stresses and cold work in the specimen that could beresponsible for localized corrosion or stress-corrosion crack-ing, or both.

7.6.2 Stress-corrosion cracking at the identifying mark is apositive indication of susceptibility to such corrosion. How-ever, the absence of cracking should not be interpreted asindicating resistance (see 4.1.7.6).

7.7 Final surface treatment of the specimens should includefinishing with No. 120 abrasive paper or cloth or the equiva-lent, unless the surface is to be used in the mill finishedcondition. This resurfacing may cause some surface workhardening, to an extent which will be determined by the vigorof the surfacing operation, but is not ordinarily significant. Thesurface finish to be encountered in service may be moreappropriate for some testing.

7.7.1 Coupons of different alloy compositions should neverbe ground on the same cloth.

7.7.2 Wet grinding should be used on alloys which workharden quickly, such as the austenitic stainless steels.

7.8 The specimens should be finally degreased by scrubbingwith bleach-free scouring powder, followed by thorough rins-ing in water and in a suitable solvent (such as acetone,methanol, or a mixture of 50 % methanol and 50 % ether), andair dried. For relatively soft metals (such as aluminum,magnesium, and copper), scrubbing with abrasive powder isnot always needed and can mar the surface of the specimen.Proper ultrasonic procedures are an acceptable alternate. Theuse of towels for drying may introduce an error throughcontamination of the specimens with grease or lint.

7.9 The dried specimens should be weighed on an analyticalbalance to an accuracy of at least60.5 mg. If cleaning deposits(for example, scouring powder) remain or lack of completedryness is suspected, then recleaning and drying is performeduntil a constant mass is attained.

7.10 The method of specimen preparation should be de-scribed when reporting test results, to facilitate interpretationof data by other persons.

7.11 The use of welded specimens is sometimes desirable,because some welds may be cathodic or anodic to the parentmetal and may affect the corrosion rate.

7.11.1 The heat-affected zone is also of importance butshould be studied separately, because welds on coupons do notfaithfully reproduce heat input or size effects of full-sizeweldments.

7.11.2 Corrosion of a welded coupon is best reported bydescription and thickness measurements rather than a millime-tre per year (mils per year) rate, because the attack is normallylocalized and not representative of the entire surface.

7.11.3 A complete discussion of corrosion testing of weldedcoupons or the effect of heat treatment on the corrosionresistance of a metal is not within the scope of this practice.

8. Test Conditions

8.1 Selection of the conditions for a laboratory corrosiontest will be determined by the purpose of the test.

8.1.1 If the test is to be a guide for the selection of a materialfor a particular purpose, the limits of the controlling factors inservice must be determined. These factors include oxygenconcentration, temperature, rate of flow, pH value, composi-tion, and other important characteristics of the solution.

8.2 An effort should be made to duplicate all pertinentservice conditions in the corrosion test.

8.3 It is important that test conditions be controlled through-out the test in order to ensure reproducible results.

8.4 The spread in corrosion rate values for duplicate speci-mens in a given test probably should not exceed610 % of theaverage when the attack is uniform.

8.5 Composition of Solution:8.5.1 Test solutions should be prepared accurately from

chemicals conforming to the Specifications of the Committeeon Analytical Reagents of the American Chemical Society5 anddistilled water, except in those cases where naturally occurringsolutions or those taken directly from some plant process areused.

8.5.2 The composition of the test solutions should becontrolled to the fullest extent possible and should be describedas completely and as accurately as possible when the results arereported.

8.5.2.1 Minor constituents should not be overlooked be-cause they often affect corrosion rates.

8.5.2.2 Chemical content should be reported as percentageby weight of the solutions. Molarity and normality are alsohelpful in defining the concentration of chemicals in some testsolutions.

8.5.3 If problems are suspected, the composition of the testsolutions should be checked by analysis at the end of the testto determine the extent of change in composition, such asmight result from evaporation or depletion.

8.5.4 Evaporation losses may be controlled by a constantlevel device or by frequent addition of appropriate solution tomaintain the original volume within61 %. Preferably, the useof a reflux condenser ordinarily precludes the necessity ofadding to the original kettle charge.

8.5.5 In some cases, composition of the test solution maychange as a result of catalytic decomposition or by reactionwith the test coupons. These changes should be determined ifpossible. Where required, the exhausted constituents should beadded or a fresh solution provided during the course of the test.

8.5.6 When possible, only one type of metal should beexposed in a given test (see 4.1.6).

5 Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, seeAnalar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and theUnited States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.

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8.6 Temperature of Solution:8.6.1 Temperature of the corroding solution should be

controlled within 61°C (61.8°F) and must be stated in thereport of test results.

8.6.2 If no specific temperature, such as boiling point, isrequired or if a temperature range is to be investigated, theselected temperatures used in the test, and their respectiveduration, must be reported.

8.6.3 For tests at ambient temperature, the tests should beconducted at the highest temperature anticipated for stagnantstorage in summer months. This temperature may be as high asfrom 40 to 45°C (104 to 113°F) in some areas. The variation intemperature should be reported also (for example, 406 2°C).

8.7 Aeration of Solution:8.7.1 Unless specified, the solution should not be aerated.

Most tests related to process equipment should be run with thenatural atmosphere inherent in the process, such as the vaporsof the boiling liquid.

8.7.2 If aeration is employed, the specimen should not belocated in the direct air stream from the sparger. Extraneouseffects can be encountered if the air stream impinges on thespecimens.

8.7.3 If exclusion of dissolved oxygen is necessary, specifictechniques are required, such as prior heating of the solutionand sparging with an inert gas (usually nitrogen). A liquidatmospheric seal is required on the test vessel to prevent furthercontamination.

8.7.4 If oxygen saturation of the test solution is desired, thiscan best be achieved by sparging with oxygen. For otherdegrees of aeration, the solution should be sparaged with air orsynthetic mixtures of air or oxygen with an inert gas. Oxygensaturation is a function of the partial pressure of oxygen in thegas.

8.8 Solution Velocity:8.8.1 The effect of velocity is not usually determined in

normal laboratory tests, although specific tests have beendesigned for this purpose.

8.8.2 Tests at the boiling point should be conducted with theminimum possible heat input, and boiling chips should be usedto avoid excessive turbulence and bubble impingement.

8.8.3 In tests below the boiling point, thermal convectiongenerally is the only source of liquid velocity.

8.8.4 In test solutions with high viscosity, supplementalcontrolled stirring with a magnetic stirrer is recommended.

8.9 Volume of Test Solution:8.9.1 The volume of the test solution should be large enough

to avoid any appreciable change in its corrosivity during thetest, either through exhaustion of corrosive constituents or byaccumulation of corrosion products that might affect furthercorrosion.

8.9.2 Two examples of a minimum “solution volume-tospecimen area” ratio are 0.20 mL/mm2 (125 mL/in.2) ofspecimen surface (Practice A 262), and 0.40 mL/mm2 (250mL/in.2).

8.9.3 When the test objective is to determine the effect of ametal or alloy on the characteristics of the test solution (forexample, to determine the effects of metals on dyes), it isdesirable to reproduce the ratio of solution volume to exposed

metal surface that exists in practice. The actual time of contactof the metal with the solution must also be taken into account.Any necessary distortion of the test conditions must beconsidered when interpreting the results.

8.10 Method of Supporting Specimens:8.10.1 The supporting device and container should not be

affected by or cause contamination of the test solution.8.10.2 The method of supporting specimens will vary with

the apparatus used for conducting the test, but should bedesigned to insulate the specimens from each other physicallyand electrically and to insulate the specimens from any metalliccontainer or supporting device used within the apparatus.

8.10.3 Shape and form of the specimen support shouldassure free contact of the specimen with the corroding solution,the liquid line, or the vapor phase as shown in Fig. 1. If cladalloys are exposed, special procedures will be required toensure that only the cladding is exposed, unless the purpose isto test the ability of the cladding to protect cut edges in the testsolution.

8.10.4 Some common supports are glass or ceramic rods,glass saddles, glass hooks, fluorocarbon plastic strings, andvarious insulated or coated metallic supports.

8.11 Duration of Test:8.11.1 Although duration of any test will be determined by

the nature and purpose of the test, an excellent procedure forevaluating the effect of time on corrosion of the metal and alsoon the corrosiveness of the environment in laboratory tests hasbeen presented by Wachter and Treseder(4). This technique iscalled the “planned interval test,” and the procedure andevaluation of results are given in Table 1. Other procedures thatrequire the removal of solid corrosion products betweenexposure periods will not measure accurately the normalchanges of corrosion with time.

8.11.2 Materials that experience severe corrosion generallydo not ordinarily need lengthy tests to obtain accurate corro-sion rates. However, there are cases where this assumption isnot valid. For example, lead exposed to sulfuric acid corrodesat an extremely high rate at first, while building a protectivefilm; then the rates decrease considerably so that furthercorrosion is negligible. The phenomenon of forming a protec-tive film is observed with many corrosion-resistant materials.Therefore, short tests on such materials would indicate a highcorrosion rate and be completely misleading.

8.11.3 Short-time tests also can give misleading results onalloys that form passive films, such as stainless steels. Withborderline conditions, a prolonged test may be needed topermit breakdown of the passive film and subsequent morerapid attack. Consequently, tests run for long periods areconsiderably more realistic than those conducted for shortdurations. This statement must be qualified by stating thatcorrosion should not proceed to the point where the originalspecimen size or the exposed area is drastically reduced orwhere the metal is perforated.

8.11.4 If anticipated corrosion rates are moderate or low, thefollowing equation gives the suggested test duration:

Hours5 2000/~corrosion rate in mpy! (2)

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where mpy = mils per year (see 11.2.1 and Note 1 forconversion to other units).

8.11.4.1Example—Where the corrosion rate is 0.25 mm/y(10 mpy), the test should run for at least 200 h.

8.11.4.2 This method of estimating test duration is usefulonly as an aid in deciding, after a test has been made, whetheror not it is desirable to repeat the test for a longer period. Themost common testing periods are 48 to 168 h (2 to 7 days).

8.11.5 In some cases, it may be necessary to know thedegree of contamination caused by the products of corrosion.This can be accomplished by analysis of the solution aftercorrosion has occurred. The corrosion rate can be calculatedfrom the concentration of the matrix metal found in thesolution and it can be compared to that determined from themass loss of the specimens. However, some of the corrosionproducts usually adhere to the specimen as a scale and thecorrosion rate calculated from the metal content in the solutionis not always correct.

8.12 The design of corrosion testing programs is furtherdiscussed in Guide G 16.

9. Methods of Cleaning Specimens after Test

9.1 Before specimens are cleaned, their appearance shouldbe observed and recorded. Location of deposits, variations intypes of deposits, or variations in corrosion products areextremely important in evaluating localized corrosion, such aspitting and concentration cell attack.

9.2 Cleaning specimens after the test is a vital step in thecorrosion test procedure and if not done properly, can causemisleading results.

9.2.1 Generally, the cleaning procedure should remove allcorrosion products from specimens with a minimum removalof sound metal.

9.2.2 Set rules cannot be applied to specimen cleaning,because procedures will vary, depending on the type of metalbeing cleaned and on the degree of adherence of corrosionproducts.

9.3 Cleaning methods can be divided into three generalcategories: mechanical, chemical, and electrolytic.

9.3.1 Mechanical cleaning includes scrubbing, scraping,brushing, mechanical shocking, and ultrasonic procedures.Scrubbing with a bristle brush and mild abrasive is the mostpopular of these methods. The others are used principally as asupplement to remove heavily encrusted corrosion productsbefore scrubbing. Care should be used to avoid the removal ofsound metal.

9.3.2 Chemical cleaning implies the removal of materialfrom the surface of the specimen by dissolution in an appro-priate chemical solution. Solvents such as acetone, carbontetrachloride, and alcohol are used to remove oil, grease, orresin and are usually applied prior to other methods ofcleaning. Chemicals are chosen for application to a specificmaterial. Methods for chemical cleaning after testing of spe-cific metals and alloys are described in Practice G 1.

9.3.3 Electrolytic cleaning should be preceded by scrubbingto remove loosely adhering corrosion products. A method ofelectrolytic cleaning is described in Practice G 1.

9.3.3.1 Precautions must be taken to ensure good electricalcontact with the specimen, to avoid contamination of thesolution with easily reducible metal ions, and to ensure thatinhibitor decomposition has not occurred.

9.4 Whatever treatment is used to clean specimens after acorrosion test, its effect in removing metal should be deter-mined and the mass loss should be corrected accordingly. A“blank” specimen should be weighed before and after exposureto the cleaning procedure to establish this mass loss (see alsoPractice G 1). Careful observation is needed to ensure thatpitting does not occur during cleaning.

9.4.1 Following removal of all scale, the specimen shouldbe treated as discussed in 5.8.

9.4.2 The description of the cleaning method should beincluded with the data reported.

10. Interpretation of Results

10.1 After corroded specimens have been cleaned, theyshould be reweighed with an accuracy corresponding to that ofthe original weighing. The mass loss during the test period canbe used as the principal measure of corrosion.

TABLE 1 Planned Interval Corrosion Test(Reprinted by permission from Chemical Engineering Progress, June

1947)Identical specimens all placed in the same corrosive fluid. Imposed

conditions of the test kept constant for entire time t + 1. Letters, A1, At, At+1, B, represent corrosion damage experienced by each test

specimen. A2 is calculated by subtracting Atfrom At+1.

Occurrences During Corrosion Test Criteria

Liquid corrosiveness unchangeddecreasedincreased

A1 = BB < A1

A1 < B

Metal corrodibility unchangeddecreasedincreased

A2 = BA2 < BB < A2

Combinations of Situations

Liquid corrosiveness Metal corrodibility Criteria

1. unchanged unchanged A1 = A2 = B2. unchanged decreased A2 < A1 = B3. unchanged increased A1 = B < A2

4. decreased unchanged A2 = B < A1

5. decreased decreased A2 < B < A1

6. decreased increased A1 > B < A2

7. increased unchanged A1 < A2 = B8. increased decreased A1 < B > A2

9. increased increased A1 < B < A2

Example; Conditions: Duplicate strips of low-carbon steel, each 19 by 76 mm(3⁄4 by 3 in.), immersed in 200 mL of 10 % AlCl3-90 % SbCl3 mixture throughwhich dried HCl gas was slowly bubbled at atmospheric pressure. Temperature90°C.

Interval,days

Mass Loss,mg

Penetration,mm (mils)

ApparentCorrosion

Rate, mm/y(mpy)

A1 0–1 1080 .043 (1.69) 15.7 (620)At 0–3 1430 .057 (2.24) 6.9 (270)At+1 0–4 1460 .058 (2.29) 5.3 (210)B 3–4 70 .003 (0.11) 1.0 (40)A2 calc. 3–4 30 .001 (0.05) 0.5 (18)

Example: A2 < B < A1

.001 < .003 < .043 (0.05 < 0.11 < 1.69)Therefore, liquid markedly decreased in corrosiveness during test, and formationof partially protective scale on the steel was indicated.

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10.2 After the specimens have been reweighed, they shouldbe examined carefully for the presence of any pits. If there areany pits, the average and maximum depths of pits are deter-mined with a pit gage or a calibrated microscope which can befocused first on the edges and then on the bottoms of the pits.The degree of lateral spreading of pits may also be noted.

10.2.1 Pit depths should be reported in millimetres orthousandths of an inch for the test period and not interpolatedor extrapolated to millimetres per year, thousandths of an inchper year, or any other arbitrary period because rarely, if ever, isthe rate of initiation or propagation of pits uniform.

10.2.2 The size, shape, and distribution of pits should benoted. A distinction should be made between those occurringunderneath the supporting devices (concentration cells) andthose on the surfaces that were freely exposed to the testsolution (see Guide G 46).

10.3 If the material being tested is suspected of beingsubject to dealloying forms of corrosion such as dezincificationor to intergranular attack, a cross section of the specimenshould be microscopically examined for evidence of suchattack.

10.4 The specimen may be subjected to simple bending teststo determine whether any embrittlement attack has occurred.

10.5 It may be desirable to make quantitative mechanicaltests, comparing the exposed specimens with uncorrodedspecimens reserved for the purpose, as described in 7.2.

11. Calculating Corrosion Rates

11.1 Calculating corrosion rates requires several pieces ofinformation and several assumptions:

11.1.1 The use of corrosion rates implies that all mass losshas been due to general corrosion and not to localizedcorrosion, such as pitting or intergranular corrosion of sensi-tized areas on welded coupons. Localized corrosion is reportedseparately.

11.1.2 The use of corrosion rates also implies that thematerial has not been internally attacked as by dezincificationor intergranular corrosion.

11.1.3 Internal attack can be expressed as a corrosion rate ifdesired. However, the calculations must not be based on massloss (except in qualification tests such as Practices A 262),which is usually small but on microsections which show depthof attack.

11.2 Assuming that localized or internal corrosion is notpresent or is recorded separately in the report, the averagecorrosion rate can be calculated by the following equation:

Corrosion rate5 ~K 3 W!/~A 3 T 3 D! (3)

where:K = a constant (see below)T = time of exposure in hours to the nearest 0.01 h,A = area in cm2 to the nearest 0.01 cm2,W = mass loss in g, to nearest 1 mg (corrected for any loss

during cleaning (see 9.4)), andD = density in g/cm3, (see Appendix X1 of Practice G 1).

11.2.1 Many different units are used to express corrosionrates. Using the above units forT, A, W, andD, the corrosionrate can be calculated in a variety of units with the followingappropriate value ofK:

Corrosion Rate Units DesiredConstant (K) in Corrosion

Rate Equationmils per year (mpy) 3.45 3 106

inches per year (ipy) 3.45 3 103

inches per month (ipm) 2.87 3 102

millimetres per year (mm/y) 8.76 3 104

micrometres per year (µm/y) 8.76 3 107

picometres per second (pm/s) 2.78 3 106

grams per square metre per hour (g/m2·h) 1.00 3 104 3 DA

milligrams per square decimetre per day (mdd) 2.40 3 106 3 DA

micrograms per square metre per second (µg/m2·s)

2.78 3 106 3 DA

___________

A Density is not needed to calculate the corrosion rate in these units. The densityin the constant K cancels out the density in the corrosion rate equation.

NOTE 1—If desired, these constants may also be used to convertcorrosion rates from one set of units to another. To convert a corrosion ratein units X to a rate of unitsY, multiply by KY/KX for example:

15 mpy5 153 [~2.783 106!/~~3.453 106!#pm/s

5 12.1 pm/s (4)

12. Report

12.1 The importance of reporting all data as completely aspossible cannot be overemphasized.

12.2 Expansion of the testing program in the future orcorrelating the results with tests of other investigators will bepossible only if all pertinent information is properly recorded.

12.3 The following checklist is a recommended guide forreporting all important information and data.

12.3.1 Corrosive media and concentration (any changesduring test).

12.3.2 Volume of test solution.12.3.3 Temperature (maximum, minimum, average).12.3.4 Aeration (describe conditions or technique).12.3.5 Agitation (describe conditions or technique).12.3.6 Type of apparatus used for test.12.3.7 Duration of each test.12.3.8 Chemical composition or trade name of metals

tested.12.3.9 Form and metallurgical conditions of specimens.12.3.10 Exact size, shape, and area of specimens.12.3.11 Treatment used to prepare specimens for test.12.3.12 Number of specimens of each material tested, and

whether specimens were tested separately or which specimenstested in the same container.

12.3.13 Method used to clean specimens after exposure andthe extent of any error expected by this treatment.

12.3.14 Initial and final masses and actual mass losses foreach specimen.

12.3.15 Evaluation of attack if other than general, such ascrevice corrosion under support rod, pit depth and distribution,and results of microscopical examination or bend tests.

12.3.16 Corrosion rates for each specimen.

G 31 – 72 (2004)

7

12.4 Minor occurrences or deviations from the proposed testprogram often can have significant effects and should bereported if known.

12.5 Statistics can be a valuable tool for analyzing theresults from test programs designed to generate adequate data.Excellent references for the use of statistics in corrosion studiesinclude Ref.(5-7) and in Guide G 16.

13. Keywords

13.1 accelerated; immersion; laboratory; mass loss; metals;pitting

REFERENCES

(1) Fisher, A. O., and Whitney, Jr., F. L., “Laboratory Methods forDetermining Corrosion Rates Under Heat Flux Conditions,”Corro-sion, Vol 15, No. 5, May 1959, p. 257t.

(2) U.S. Patent 3,228,236, 1969.(3) “Stress Corrosion Test Environments and Test Durations,”Symposium

on Stress Corrosion Testing, ASTM STP 425, ASTM, 1967.(4) Wachter, A., and Treseder, R. S., “Corrosion Testing Evaluation of

Metals for Process Equipment,”Chemical Engineering Progress, Vol43, June 1947, pp. 315–326.

(5) Mickley, H. S., Sherwood, T. K., and Reed, C. E. editors,Applied

Mathematics in Chemical Engineering2nd Edition, McGraw-HillBook Co., New York, NY 1957.

(6) Youden, W. J.,Experimentation and Measurement, National ScienceTeachers Assn., Washington, DC, 1962.

(7) Booth, F. F., and Tucker, G. E. G., “Statistical Distribution ofEndurance in Electrochemical Stress-Corrosion Tests,”Corrosion, Vol21, No. 5, May 1965, pp. 173–177.

(8) Champion, F. A.,Corrosion Testing Procedures, 2nd Edition, JohnWiley & Sons, Inc., New York, NY, 1965.




G 31 – 72 (2004)

8

INTERNATIONAL

Designation: D 638 - 02a

Standard Test Method forTensile Properties of Plastics

Ths standard is issued under the fixed designation D 638; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (E) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1. Scope *

1.1 This test method covers the determination of the tensileproperties of unreinforced and reinforced plastics in the formof standard dumbbell-shaped test specimens when tested underdefined conditions of pretreatment, temperature, humidity, andtesting machine speed.

1.2 This test method can be used for testing materials of anythickness up to 14 mm (0.55 in.). However, for testingspecimens in the form of thn sheeting, including film less than1.0 mm (0.04 in.) in thickness, Test Methods D 882 is thepreferred test method. Materials with a thickness greater than14 mm (0.55 in. ) must be reduced by machining.

1.3 This test method includes the option of determningPoisson s ratio at room temperature.

NOTE I-This test method and ISO 527- 1 are tech;.cally equivalent.NOTE 2-This test method is not intended to cover precise physical

procedures. It is recognized that the constant rate of crosshead movementtype of test leaves much to be desired from a theoretical standpoint, thatwide differences may exist between rate of crosshead movement and rateof strain between gage marks on the specimen, and that the testing speedsspecified disguise important effects characteristic of materials in theplastic state. Furter, it is realized that varations in the thicknesses of testspecimens, which are permtted by these procedures, produce varations inthe surface-volume ratios of such specimens, and that these varations mayinfluence the test results. Hence, where directly comparable results aredesired , all samples should be of equal thckness. Special additional testsshould be used where more precise physical data are needed.

NOTE 3- This test method may be used for testing phenolic moldedresin or lamnated materials. However, where these materials are used aselectrcal insulation, such materials should be tested in accordance withTest Methods D 229 and Test Method D 651.NOTE 4-For tensile properties of resin-matrx composites reinforced

with oriented continuous or discontinuous high modulus 20-GPa0 X 10 psi) fibers, tests shall be made in accordance with Test

Method D 3039/D 3039M.

1.4 Test data obtained by this test method are relevant andappropriate for use in engineering design.

5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.

1 This test method is under the jurisdiction of ASTM Commttee D20 on Plastics

and is the direct responsibilty of Subcommttee D20. 1O on Mechancal Propertes.Current edition approved November 10, 2002. Published Januar 2003. Origi-

nally approved in 1941. Last previous edition approved in 2002 as D 638 - 02.

1.6 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.

2. Referenced Documents1 ASTM Standards:

D 229 Test Methods for Rigid Sheet and Plate MaterialsUsed for Electrical Insulation

D 412 Test Methods for Vulcanized Rubber and Thermo-plastic Elastomers- Tension

D 618 Practice for Conditioning Plastics for TestingD 651 Test Method for Tensile Strength of Molded Electri-

cal Insulating MaterialsD 882 Test Methods for Tensile Properties of Thin Plastic

SheetingD 883 Terminology Relating to PlasticsD 1822 Test Method for Tensile-Impact Energy to Break

Plastics and Electrical Insulating MaterialsD 3039/D 3039M Test Method for Tensile Properties of

Polymer Matrix Composite MaterialsD 4000 Classification System for Specifying Plastic Mate-

rials 7

D 4066 Classification System for Nylon Injection and Ex-trusion Materials 7

D 5947 Test Methods for Physical Dimensions of SolidPlastic Specimens

E 4 Practices for Force Verification of Testing MachinesE 83 Practice for Verification and Classification of Exten-

someterE 132 Test Method for Poisson s Ratio at Room Tempera-

tureE 691 Practice for Conducting an Interlaboratory Study to

Annual Book of ASTM Standards Vol 10.01.

Annual Book of ASTM Standards Vol 09.01.4 Annual Book of ASTM Standards Vol 08.01.5 Discontinued; see 1994 Annual Book of ASTM Standards Vol 10.01.

Annual Book of ASTM Standards Vol 15.03.

Annual Book of ASTM Standards, Vol 08.02.

Annual Book of ASTM Standards Vol 08.03.9 Annual Book of ASTM Standards Vol 03.01.

* A Sumary of Changes section appears at the end of this standard.

Copyright ASTM International , 100 Barr Harbor Drive , PO Box C700, West Conshohocken , PA 19428-2959 , United States.

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o D638- 02a

Determe the Precision of a Test MethodISO' Standard:

ISO 527- 1 Determation of Tensile Propertes

i Termnology

1 Definitions-Definitions of terms applying to ths test

method appear in TermnologyD 883 and Anex A2.

4. Signcance and Use

1 Ths test method is designed to produce tensile property

data for the control and specification of plastic materials. Thesedata are also useful for qualitative characterization and for

research and development. For many materials, there may be a

specification that requires the use of ths test method, but with

some procedural modifications that take precedence when

adhering to the specification. Therefore, . it is advisable to referto that material specification before using ths test method.Table 1 in Classification D 4000 lists the ASTM materialsstadards. that curently exist.

2 Tensile properties may var with specimen preparationand with speed and environment of testing. Consequently,where precise comparative results are desired, these factors

must be carefully controlled.4.2. 1 It is realzed that a material canot be tested without

also testing the method of preparation of that material. Hence,when comparative tests of materials per se are desired, the

greatest care must be exercised to ensure that al samples areprepared in exactly the same way, unless the test is to includethe effects of sample preparation. Similarly, for referee pur-poses or comparsons withn any given series of specimens,care must be taken to secure the maxmum degree of unior-mity in details of preparation, treatment, and handlg.

4.3 Tensile propertes may provide useful data for plasticsengineering design puroses. Bowever, because of the highdegree of sensitivity e bitedby many plastics to rate of

straining and environme tal conditions , data obtained by thstest method canot be considered valid for applications involv-ing load-time scales or environments widely different fromthose of ths test method. In cases of such dissimilarty,reliable estiation of the limit of usefulness can be made formost plastics. Ths sensitivity to rate of straining and environ-ment necessitates testig over a broad load-time scale (includ-ing impact and creep) and range of environmental conditionstensile properties are to suffce for engineering design pur-

poses.

NOT 5-Since the existence of a tre elastic limit in plastics (as inmany other organc materials and in many metas) is debatable, thepropriety of applying the term "elastic modulus" in its quoted, generalyaccepted definition to describe the "stiess" or "rigidity" of a plastic hasbeen seriously questioned. The exact stress-strain characteristics of plasticmaterials are highly dependent on such factors as rate of application ofstress , temperatue, previous history of specimen, etc. However, stress-strai cures for plastics,. determed as described in ths test methodalmost always show a liear region at low stresses, and a straight linedrawn tangent to this porton of the cure permts calculation of an elastic

10 Annual Book of ASTM Standrds Vol 14.02.11 Avaiable from American National Stadards Institute, 25 W. 43rdSt. , 4th

Floor, New York, NY 10036.

modulus of the usualy defined type. Such a constant is useful if itsarbitrar nature and dependence on time, temperatue, and simlar factorsare realized.

4.4 Poisson s Ratio-When uniaxial tensile force is appliedto a solid, the solid stretches in the direction of the appliedforce (axially), but it also contracts in both diensions lateralto the applied force. If the solid is homogeneous and isotropicand the material remains elastic under the action of the appliedforce, the lateral strain bears a constant relationship to the axialstrain. Ths constant, called Poisson s ratio, is defined as thenegative ratio of the transverse (negative) to axial strain underuniaxial stress.

4.4. 1 Poisson s ratio is used for the design of strctues inwhich all dimensional changes resulting from the applicationof force need to be taken into account and in the application ofthe generalized theory of elasticity to strctual analysis.

NOTE 6-The accuracy of the determnation of Poisson s ratio isusually limited by the accuracy of the transverse strain measurementsbecause the percentage errors in these measurements are usualy greaterthan in the axal strain measurements. Since a ratio rather than an absolutequantity is measured, it is only necessar to know accurately the relativevalue of the calbration factors of the extensometers, Also, in general, the

value of the applied loads need not be known accurately.

5. Apparatus1 Testing Machine- testig machine of the constat-

rate-of-crosshead-movement type and comprising essentialy

the following:

1.1 Fixed Member- fixed or essentially stationarmember caring one grp.

1.2 Movable Member- movable member caring asecond grp. .

1.3 Grips-Grips for holding the test specimen betweenthe fixed member and the movable member of the testingmachie can be either the fixed or self-algng type.

1..1 Fixed grps are rigidly attached to the fixed andmovable members of the testig machie. When ths type ofgrip is used extreme care should be taken to ensure that the testspecimen is inserted and clamped so that the long axis of thetest specimen coincides with the diection of pull though thecenter line of the grip assembly.

1.3.2 Self-algnng grps are attached to the fixed andmovable members of the testing machine in such a maner thatthey wil move freely into algnent as soon as any load isapplied so that the long axs of the test specimen wil coincidewith the diection of the applied pull though the center line ofthe grp assembly. The specimens should be aligned as per-

fectly as possible with the diection of pull so that no rotarmotion that may induce slippage wil occur in the grps; thereis a lit to the amount of misalgnent self-alignig grps wilaccommodate.

1.3.3 The test specimen shal be held in such a way thatslippage relative to the grps is prevented insofar as possible.Grip suraces that are deeply scored or serrated with a patternsimar to those of a coarse single-cut file, serrations about 2.4mm (0.09 in.) apar and about 1.6 mm (0.06 in.) deep, havebeen found satisfactory for most thermoplastics. Finer serra-tions have been found to be more satisfactory for harderplastics, such as the thermosettig materials. The serrations

cO D638- 02a

should be kept clean and shar. Breakng in the grips mayoccur at ties, even when deep serrations or abraded specimensurfaces are used; other technques must be used in these cases.Other technques that have been found useful, parcularly withsmooth-faced grips , are abrading that portion of the surface ofthe specimen that wil be in the grips, and interposing thinpieces of abrasive cloth, abrasive paper, or plastic , or rubber-coated fabric, commonly called hospital sheeting, between thespecimen and the grp surface. No. 80 double-sided abrasivepaper has been found effective in many cases. An open-meshfabric, in which the theads are coated with abrasive, has also

been effective. Reducing the cross-sectional area of the speci-men may also be effective. The use of special types of grips issometimes necessar to eliminate slippage and breakage in thegrps. /

1.4 Drive Mechanism- drve mechanism for imparingto the movable member a uniform, controlled velocity withrespect to the stationar member, with this velocity to beregulated as specified in Section 8.

1.5 Load Indicator- suitable load-indicating mecha-nism capable of showing the total tensile load cared by thetest specimen when held by the grips. Ths mechansm shall be

essentially free of inertia lag at the specified rate of testing andshall indicate the load with an accuracy of:! 1 % of theindicated value, or better. The accuracy of the testing machineshall be verified in accordance with Practices E 4.

NOTE 7-Experience has shown that many testing machines now in useare incapable of maintaing accuracy for as long as the periods betweeninspection recommended in Practices E 4. Hence, it is recommended thateach machie be studied individually and verified as often as may befound necessar. It frequently wil be necessar to perform this functiondaily.

1.6 The fixed member, movable member, drive mecha-nism, and grps shall be constrcted of such materials and insuch proportions that the total elastic longitudinal strain of thesystem constituted by these pars does not exceed 1 % of thetotal longitudinal strain between the ,two gage marks on the testspecimen at any time during the test and at any load up to therated capacity of the machine.

7 Crosshead Extension Indicator- suitable extensionindicating mechanism capable of showing the amount ofchange in the separation of the grips, that is, crosshead

movement. This mechansm shal be essentially free of inertiallag at the specified rate of testing and shall indicate thecrosshead movement with an accuracy of :! 10 % of theindicated value.

2 Extension Indicator (extensometer)-A suitable instr-ment shall be used for determning the distance between two

designated points within the gage length of the test specimen asthe specimen is stretched. For referee purposes , the extensom-

eter must be set at the full gage length of the specimen, as

shown in Fig. 1. It is desirable, but not essential, that thisinstrment automatically record ths distance, or any change in

, as a function of the load on the test specimen or of theelapsed time from the star of the test, or both. If only the latteris obtained, load-time data must also be taken. This instrmentshall be essentially free of inerta at the specified speed of

testing. Extensometers shall be classified and their calibrationperiodically verified in accordance with Practice E 83.

1 Modulus-of-Elasticity Measurements-For modulus-

of-elasticity measurements , an extensometer with a maximumstrain error of 0.0002 rnmm (in./in.) that automatically andcontinuously records shall be used. An extensometer classifiedby Practice E 83 as fulfilling the requirements of a B-classification within the range of use for modulus measure-ments meets this requirement.

2 Low-Extension Measurements-For elongation-at-yield and low-extension measurements (nominally 20 % or

less), the same above extensometer, attenuated to 20 % exten-

sion, may be used. In any case , the extensometer system must

meet at least Class C (Practice E 83) requirements, whichinclude a fixed strain error of 0.001 strain or :! 1.0 % of theindicated strain , whichever is greater.

3 High-Extension Measurements-For making mea-

surements at elongations greater than 20 % , measuring tech-

niques with error no greater than:! 10 % of the measured value

are acceptable.

2.4 Poisson s Ratio-Bi-axial extensometer or axial andtransverse extensometers capable of recording axial strain andtransverse strain simultaneously. The extensometers shall becapable of measuring the change in strains with an accuracy of1 % of the relevant value or better.

NOTE 8-Strain gages can be used as an alternative method to measureaxial and transverse strain; however, proper techniques for mountingstrain gages are crucial to obtaining accurate data. Consult strain gage

suppliers for instruction and training in these special techniques.

3 Micrometers-Suitable micrometers for measuring thewidth and thickness of the test specimen to an incremental

discrimination of at least 0.025 mm (0.001 in.) should be used.All width and thickness measurements of rigid and semirigid

plastics may be measured with a hand micrometer with ratchet.A suitable instrument for measuring the thickness of nonrgidtest specimens shall have: (1) a contact measuring pressure of25 :! 2.5 kPa (3.6 :! 0.36 psi), (2) a movable circular contactfoot 6.35 :! 0.025 mm (0.250 :! 0.001 in.) in diameter, and (3)

a lower fixed anvil large enough to extend beyond the contactfoot in all directions and being parallel to the contact footwithin 0.005 mm (0.0002 in.) over the entire foot area. Flatnessof the foot and anvil shall conform to Test Method D 5947.

1 An optional instrument equipped with a circular con-tact foot 15.88 :! 0.08 mm (0.625 :! 0.003 in.) in diameter isrecommended for thickness measuring of process samples orlarger specimens at least 15.88 mm in minimum width.

6. Test Specimens1 Sheet, Plate, and Molded Plastics:1 Rigid and Semirigid Plastics-The test specimen shall

conform to the dimensions shown in Fig. 1. The Type 1specimen is the preferred specimen and shall be used wheresuffcient material having a thickness of 7 mm (0.28 in.) or less

is available. The Type II specimen may be used when amaterial does not break in the narow section with the preferredType I specimen. The Type V specimen shall be used whereonly limited material having a thickness of 4 mm (0.16 in.) or

less is available for evaluation , or where a large number of

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TYPES ,. II, III & V

TYPE IV

Specimen Dimensions for Thickness, T, mm (in.

Dimensions (see drawings)7 (0.28) or under Over 7 to 14 (0.28 to 0.55), incl 4 (0.16) or under

TolerancesType I Type II Type III Type IV Type

13 (0.50) 6 (0.25) 19 (0.75) 6 (0.25) 18 (0. 125) :!0. (:!0.02)B,

57 (2.25) 57 (2.25) 57 (2.25) 33 (1.30) 53 (0.375) :!0. (:!0.02)c19 (0.75) 19 (0.75) 29 (1. 13) 19 (0.75) + 6.4 ( + 0.25)

53 (0.375) + 3.18 (+ 0. 125)165 (6. 183 (7. 246 (9. 115 (4. 63.5 (2. no max (no max)50 (2.00) 50 (2.00) 50 (2.00) 62 (0.300) :!0.25 (:!0.010)c

25 (1.00) :!0.13 (:!0.005)115 (4. 135 (5. 115 (4. 65 (2. 25.4 (1. :!5 (:!0.

76 (3.00) 76 (3.00) 76 (3.00) 14 (0.56) 12.7 (0. :!1 (:!0.04)c25 (1.00) :!1 (:!0.04)

W-Width of narrow sectionL-Length of narrow sectionWo-Width overall , minWo-Width overall, minLo-Length overall, minG-age length'G-age length

D-Distance between gripsR-Radius of filetRO-uter radius (Type IV)

A Thickness, shall be 3.2:! 0.4 mm (0.13 :! 0.02 in.) for all types of molded specimens, and for other Types I and II specimens where possible. If specimens aremachined from sheets or plates , thickness, may be the thickness of the sheet or plate provided this does not exceed the range stated for the intended specimen type.For sheets of nominal thickness greater than 14 mm (0.55 in.) the specimens shall be machined to 14 :! 0.4 mm (0.55 :! 0.02 in.) in thickness, for use with the Type III

specimen. For sheets of nominal thickness between 14 and 51 mm (0.55 and 2 in. ) approximately equal amounts shall be machined from each surface. For thicker sheetsboth surfaces of the specimen shall be machined , and the location of the specimen with reference to the original thickness of the sheet shall be noted. Tolerances onthickness less than 14 mm (0.55 in.) shall be those standard for the grade of material tested.

For the Type IV specimen , the intemal width of the narrow section of the die shall be 6.00 :! 0.05 mm (0.250:! 0.002 in. ). The dimensions are essentially those of Die

C in Test Methods D 412.The Type V specimen shall be machined or die cut to the dimensions shown, or molded in a mold whose cavity has these dimensions. The dimensions shall be:W= 18 :! 0.03 mm (0.125 :! 0.001 in.

= 9.53 :! 0.08 mm (0.375 :! 0.003 in.G = 7.62 :! 0.02 mm (0.300 :! 0.001 in.), andR= 12.7 :! 0.08 mm (0.500 :! 0.003 in.

The other tolerances are those in the table.Supporting data on the introduction of the L specimen of Test Method D 1822 as the Type V specimen are available from ASTM Headquarters. Request RR:D20-1 038.

The width at the center shall be +0.00 mm, - 10 mm ( +0.000 in.

, -

004 in.) compared with width Wat other parts of the reduced section. Any reduction in

at the center shall be gradual, equally on each side so that no abrupt changes in dimension result.For molded specimens, a draft of not over 0. 13 mm (0.005 in.) may be allowed for either Type I or II specimens 3.2 mm (0. 13 in.) in thickness, and this should betaken

into account when calculating width of the specimen. Thus a typical section of a molded Type I specimen , having the maximum allowable draft, could be as follows:G Overall widths greater than the minimum indicated may be desirable for some materials in order to avoid breaking in the grips.

Overall lengths greater than the minimum indicated may be desirable either to avoid breaking in the grips or to satisfy special test requirements.Test marks or initial extensometer span.When self-tightening grips are used, for highly extensible polymers, the distance between grips wil depend upon the types of grips used and may not be critical ifmaintained uniform once chosen.

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FIG. 1 Tension Test Specimens for Sheet, Plate, and Molded Plastics

specimens are to be exposed in a limited space (thermal andenvironmental stabilty tests, etc.). The Type IV specimen

should be used when diect comparsons are requied betweenmaterials in different rigidity cases (that is, nonrgid and

D638- 02a

semigid). The Type II specimen must be used for all

materials with a thickness of greater than 7 mm (0.28 in.) butnot more than 14 mm (0.55 in.

1.2 Nonrigid Plastics-The test specimen shall conformto the dimensions shown in Fig. 1. The Type IV specimen shallbe used for testing nonrgid plastics with a thickness of 4 mm(0. 16 in.) or less. The Type II specimen must be used for all

materials with a thckness greater than 7 mm (0.28 in.) but notmore than 14 mm (0.55 in.

1.3 Reinforced Composites-The test specimen for rein-forced composites, including highly ortotropic laminates

shall conform to the dimensions of the Type I specimen shownin Fig. 1.

1.4 Preparation-Test specimens shall be prepared bymachining operations , or die cutting, from materials in sheetplate, slab, or similar form. Materials thicker than 14 mm (0.in. ) must be machined to 14 mm (0.55 in.) for use as Type specimens. Specimens can also be prepared by molding the

material to be tested.

NOTE 9-Test results have shown that for some materials such as glasscloth, SMC, and BMC laminates, other specimen types should beconsidered to ensure breakage within the gage length of the specimen, as

mandated by 7.NOTE 100When preparng specimens from certain composite lami-

nates such as woven roving, or glass cloth, care must be exercised in

cutting the specimens parallel to the reinforcement. The reinforcementwil be significantly weakened by cuttng on a bias, resulting in lowerlaminate properties, unless testing of specimens in a direction other thanparallel with the reinforcement constitutes a varable being studied.NOTE II-Specimens prepared by injection molding may have different

tensile propertes than specimens prepared by machining or die-cuttingbecause of the orientation induced. Ths effect may be more pronouncedin specimens with narow sections.

2 Rigid Tubes-The test specimen for rigid tubes shall beas shown in Fig. 2. The length shall be as shown in the tablein Fig. 2. A groove shall be machined around the outside of thespecimen at the center of its length so that the wall section aftermachining shall be 60 % of the original nominal wall thick-ness. This groove shall consist of a straight section 57.2 mm(2.25 in.) in length with a radius of 76 mm (3 in.) at each endjoining it to the outside diameter. Steel or brass plugs havingdiameters such that they wil fit snugly inside the tube andhaving a length equal to the full jaw length plus 25 mm (1 in.shall be placed in the ends of the specimens to preventcrushing. They can be located conveniently in the tube byseparating and supporting them on a theaded metal rod.Details of plugs and test assembly are shown in Fig. 2.

3 Rigid Rods-The test specimen for rigid rods shall be asshown in Fig. 3. The length, shall be as shown in the tablein Fig. 3. A groove shall be machined around the specimen atthe center of its length so that the diameter of the machinedportion shall be 60 % of the original nominal diameter. Ths

groove shall consist of a straight section 57.2 mm (2.25 in.) inlength with a radius of 76 mm (3 in.) at each end joining it tothe outside diameter.

6.4 All surfaces of the specimen shall be free of visibleflaws , scratches, or imperfections. Marks left by coarse ma-chining operations shall be carefully removed with a fine file orabrasive, and the filed surfaces shall then be smoothed withabrasive paper (No. 00 or finer). The finishing sanding strokes

89 mm, min.(3.50 in.

51 mm, min.(2.00 in,

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51 mm, min.(2.00 in.

89 mm, min.(3.50 in.

Machine to60% of

Original NominalDiameter

DIMENSIONS OF ROD SPECIMENS

Nominal Diam- Length of Radialeter Sections, 2R.

Total CalculatedMinimum

Length of Specimen

Standard Length

Specimen to Be Used

for 89-mm (3'1- in.

Jaws

mm (in.

2 (Ve) 19.6 (0.773) 356 (14.02) 381 (15)7 ('116) 24.0 (0.946) 361 (14.20) 381 (15)4 (V.) 27.7 (1.091) 364 (14.34) 381 (15)

5 (3f) 33.9 (1.333) 370 (14.58) 381 (15)12.7 ('1) 39.0 (1.536) 376 (14.79) 400 (15.75)

15.9 (S/) 43.5 (1.714) 380 (14.96) 400 (15.75)

19.0(%) 47.6 (1.873) 384 (15. 12) 400 (15.75)

22.2 (7e) 51.5 (2.019) 388 (15.27) 400 (15.75)

25.4 (1) 54.7 (2.154) 391 (15.40) 419 (16.

31.8 (1V.) 60.9 (2.398) 398 (15.65) 419 (16.

38. 1 (1 V2) 66.4 (2.615) 403 (15.87) 419 (16.42.5 (1%) 71.4 (2. 812) 408 (16.06) 419 (16.

50.8 (2) 76.0 (2.993) 412 (16.24) 432 (17)

A For other jaws greater than 89 mm (3.5 in.), the standard length shall beincreased by twice the length of the jaws minus 178 mm (7 in.). The standardlength permits a slippage of approximately 6.4 to 12.7 mm (0.25 to 0.50 in. ) in each

jaw while maintaining the maximum length of the jaw grip.

FIG. 3 Diagram Showing Location of Rod Tension Test Specimenin Testing Machine

shall be made in a direction parallel to the long axis of the testspecimen. All flash shall be removed from a molded specimen,takng great care not to disturb the molded surfaces. Inmachining a specimen, undercuts that would exceed the

dimensional tolerances shown in Fig. 1 shall be scrupulouslyavoided. Care shall also be taken to avoid other commonmachining errors.

, L,

! Usedin.

hall be:andardin each

:imen

Ie testimen,s. In

d the

louslynmon

50 in. , min.(89mm)

00 in. , min.(51 mm)

-- 3.00 in. Rad.S. (70 mm)

25 in.(57mm)

00 in. Rad.

S. (70 mm)

00 in., min.(51 mm)

50 in., min.(89 mm)

o D638- 02a

r Meta I Plugs

063 in. Rad.(1.6mm)

Machine to60%ofOriginalNominal

Wan Thickness

063 in. Rad.(1.6 mm)

DIMENSIONS OF TUBE SPECIMENS

Length of Radial Total CalculatedStandard Length

Nominal Wall Sections Minimumof Specimen to Be

Thickness Used for 89-mm2R. Length of Specimen (3. in.) Jaws

mm (in.

79 (Y32) 13.9 (0.547) 350 (13.80) 381 (15)

1.2 (364) 17.0 (0:670) 354 (13.92) 381 (15)

6 (V's) 19.6 (0.773) 356 (14.02) 381 (15)

2.4 (%2) 24.0 (0.946) 361 (14.20) 381 (15)

2 (Va) 27.7 (1.091) 364 (14.34) 381 (15)

8 (3/1S) 33.9 (1.333) 370 (14.58) 381 (15)

6.4 (V4) 39.0 (1.536) 376 (14.79) 400 (15.75)

9 (SAs) 43.5 (1.714) 380 (14.96) 400 (15.75)

5 (3/) 47.6 (1.873) 384 (15. 12) 400 (15.75)

11. (7As) 51.3 (2.019) 388 (15.27) 400 (15.75)

12.7 (V2) 54.7 (2.154) 391 (15.40) 419 (16.

A For other jaws greater than 89 mm (3.5 in.), the standard length shall beincreased by twice the length of the jaws minus 178 mm (7 in.). The standardlength permits a slippage of approximately 6.4 to 12.7 mm (0.25 to 0.50 in. ) in each

jaw while maintaining the maximum length of the jaw grip.

FIG. 2 Diagram Showing Location of Tube Tension TestSpecimens in Testing Machine

5 If it is necessar to place gage marks on the specimenths shall be done with a wax crayon or India ink that wil notafect the material being tested. Gage marks shall not bescratched, punched, or impressed on the specimen.

6 When testing materials that are suspected of anisotropy,duplicate sets of test specimens shall be prepared, having theirlong axes respectively parallel with, and normal to, the

suspected direction of anisotropy.

7. Number of Test Specimens

1 Test at least five specimens for each sample in the caseof isotropic materials.

2 Test ten specimens , five normal to, and five parallel

with, the principle axis of ansotropy, for each sample in thecase of ansotropic materials.

7.3 Discard specimens that break at some flaw, or that break

outside of the narow cross-sectional test section (Fig. 1dimension " ), and make retests, unless such flaws constitutea varable to be studied.

NOTE 12-Before testing, all transparent specimens should be inspectedin a polarscope. Those which show atypical or concentrated strain

patterns should be rejected, unless the effects of these residual strainsconstitute a varable to be studied.

8. Speed of Testing

1 Speed of testing shall be the relative rate of motion ofthe grips or test fixtures during the test. The rate of motion ofthe drven grip or fixtue when the testing machine is running

idle may be used, if it can be shown that the resulting speed oftesting is. withn the limits of varation allowed.

2 Choose the speed of testing from Table 1. Determnethis chosen speed of testing by the specification for the materialbeing tested, or by agreement between those concerned. Whenthe speed is not specified, use the lowest speed shown in Table1 for the specimen geometr being used, which gives rupturewithin 1/2 to 5-min testing time.

3 Modulus determnations may be made at the speed

selected for the other tensile properties when the recorder

response and resolution are adequate.

TABLE 1 Designations for Speed of Testing

ClassificationSpeed of Testing,mm/min (in.lmin)

NominalStrain C Rate at

Start of Testmmlmm. min(in.lin. .min)

Specimen Type

Rigid and Semirigid , II , III rods andtubes

5 (0.2) :' 25 %

50 (2) :' 10 % 500 (20) :' 10 % 5 (0.2) :' 25 % 0.50 (2) :' 10 % 1 .

500 (20) :' 10 % 1 (0.05) :' 25 % 0.10 (0.5) :! 25 % 100 (5):! 25 % 50 (2) :! 10 %

500 (20) :! 10 % 50 (2) :! 10 % 1 .

500 (20) :! 10 % A Select the lowest speed that produces rupture in V2 to 5 min for the specimen

geometry being used (see 8.2).

See Terminology D 883 for definitions.The initial rate of straining cannot be calculated exactly for dumbbell-shaped

specimens because of extension , both in the reduced section outside the gagelength and in the filets. This initial strain rate can be measured from the initial slopeof the tensile strain-versus-time diagram.

Nonrigid III

cO D638- 02a

8.4 Poisson s ratio determnations shall be made at the samespeed selected for modulus determnations.

9. Conditioning

1 Conditioning-Condition the test specimens at 23 C (73.4 :! 3. F) and 50 :! 5 % relative humidity for not less

than 40 h prior to test in accordance with Procedure A ofPractice D 618, unless otherwise specified by contract or therelevant ASTM material specification. Reference pre-test con-ditioning, to settle disagreements, shall apply tolerances of:! 1 C (1.8 F) and ::2 % relative humidity.

2 Test Conditions-Conduct the tests at 23 :! 2 C (73.4 :!F) and 50 :! 5 % relative humidity, unless otherwise

specified by contract or the relevant ASTM material specifica-tion. Reference testing conditions, to settle disagreements

shall apply tolerances of :! 1 DC (1.8 F) and ::2 % relativehumidity.

10. Procedure10. 1 Measure the width and thckness of rigid flat speci-

mens (Fig. 1) with a suitable micrometer to the nearest 0.025mm (0.001 in.) at several points along their narow sections.Measure the thckness of nonrgid specimens (produced by a

Type IV die) in the same maner with the required dialmicrometer. Take the width of ths specimen as the distancebetween the cutting edges of the die in the narow section.Measure the diameter of rod specimens, d the inside and

outside diameters of tube specimens, to the nearest 0.025 mm(0.001 in.) at a minimum of two points 90 apar; make these

measurements along the groove for specimens so constrcted.Use plugs in testing tube specimens, as shown in Fig. 2.

TABLE 2 Modulus, 10 psi, for Eight Laboratories, Five MaterialsMean S SR

00890179017905370894

071035063217266

025051051152253

201144144614753

PolypropyleneCellulose acetate butyrate

AcrylicGlass-reinforced nylon

Glass-reinforced polyester

210246

0.481

10.2 Place the specimen in the grps of the testing machie,takng care to algn the long axs of the specimen and the grpswith an imaginar line joinng the points of attachment of thegrps to the machine. The distance between the ends of thegripping suraces, when using flat specimens, shall be asindicated in Fig. 1. On tube and rod specimens, the location forthe grps shall be as shown in Fig. 2 and Fig. 3. Tighten thegrps evenly and firmy to the degree necessar to preventslippage of the specimen during the test, but not to the pointwhere the specimen would be crushed.

10.3 Attach the extension indicator. When modulus is beingdetermned, a Class B-2 or better extensometer is required (see

1).

NOTE 13-Modulus of materials is determned from the slope of thelinear porton of the stress-strain cure. For most plastics, ths linearporton is very smal, occurs very rapidly, and must be recorded automati-cally. The change in jaw separation is never to be used for calculatingmodulus or elongation.

10. Poisson s Ratio Determination:10. 1.1 When Poisson s ratio is determned, the speed of

testing and the load range at which it is determined shall be thesame as those used for modulus of elasticity.

10. 1.2 Attach the transverse strain measuring device. Thetransverse strain measuring device must continuously measurethe strain simultaneously with the axial strain measuringdevice.

TABLE 3 Tensile Stress at Yield, psi, for Eight LaboratoriesThree Materials

Mean

Polypropylene 022 161 062 0.456Cellulose acetate butyrate 058 227 164 642Acrylic 10.4 067 317 190 897

TABLE 4 Elongation at Yield, %, for Eight Laboratories, ThreeMaterials

Mean

Cellulose acetate butyrate

AcrylicPolypropylene 0.45 16.

10. 1.3 Make simultaneous measurements of load andstrain and record the data. The precision of the value ofPoisson s ratio wil depend on the number of data points ofaxial and transverse strain taken.

10.4 Set the speed of testing at the proper rate as required inSection 8, and star the machine.

10.5 Record the load-extension curve of the specimen.10.6 Record the load and extension at the yield point (if one

exists) and the load and extension at the moment of rupture.

NOTE 14-If it is desired to measure both modulus and failure proper-ties (yield or break, or both), it may be necessar, in the case of highlyextensible materials , to run two independent tests. The high magnificationextensometer normally used to determine properties up to the yield pointmay not be suitable for tests involving high extensibility. If allowed toremain attached to the specimen, the extensometer could be permanentlydamaged. A broad-range incremental extensometer or hand-rule techniquemay be needed when such materials are taken to rupture.

11. Calculation

11. 1 Toe compensation shall be made in accordance withAnnex AI , unless it can be shown that the toe region of thecurve is not due to the take-up of slack, seating of the

specimen, or other artifact, but rather is an authentic materialresponse.

11.2 Tensile Strength-Calculate the tensile strength by

dividing the maximum load in newtons (or pounds-force) bythe original minimum cross-sectional area of the specimen insquare metres (or square inches). Express the result in pascals(or pounds-force per square inch) and report it to threesignificant figures as tensile strength at yield or tensile strengthat break, whichever term is applicable. When a nominal yieldor break load less than the maximum is present and applicable,it may be desirable also to calculate, in a similar manner, thecorresponding tensile stress at yield or tensile stress at breakand report it to thee significant figures (see Note A2.8).

leed ofl be the

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o D638- 02a

11.3 Elongation values are valid and are reported in caseswhere uniformty of deformation within the specimen gage

lengt is present. Elongation values are quantitatively relevant

and appropriate for engineerig design. When non-uniform

deformation (such as necking) occurs within the specimen gagelength nominal strain values are reported. Nominal strainvalues are of qualtative utility only.

--

Axial Strain, Ea

shall be calculated whenever possible. However, for materialswhere no proportionalty is evident, the secant value shall becalculated. Draw the tangent as directed in A1.3 and Fig. A1.and mark off the designated strain from the yield point wherethe tangent line goes though zero stress. The stress to be usedin the calculation is then determned by dividing the load-extension curve by the original average cross-sectional area of

-0 Transverse Strain, Et

Applied Load, P

FIG. 4 Plot of Strains Versus Load for Determination of Poisson s Ratio

11.3. 1 Percent Elongation-Percent elongation is the

change in gage length relative to the original specimen gagelength, expressed as a percent. Percent elongation is calculatedusing the apparatus described in 5.

11.3. 1.1 Percent Elongation at Yield-Calculate the percentelongation at yield by reading the extension (change in gagelengt) at the yield point. Divide that extension by the originalgage length and multiply by 100.

11.3. 1.2 Percent Elongation at Break-Calculate the per-

cent elongation at break by reading the extension (change ingage length) at the point of specimen rupture. Divide thatextension by the original gage length mid multiply by 100.

11..2 Nominal Strain-Nomial strain is the change in grpseparation relative to the original grp separation expressed a percent. Nominal strain is calculated using the apparatusdescribed in 5. 1.7.

11.3. 1 Nominal strain at break-Calculate the nominal

strai at break by reading the extension (change in grip

separation) at the point of rupture. Divide that extension by theoriginal grp separation and multiply by 100.

11.4 Modulus of Elasticity-Calculate the modulus of elas-ticity by extending the intial linear porton of the load-extension curve and dividing the difference in stress corre-

sponding to any segment of section on this straight lie by thecorrespondig difference in strain. All elastic modulus valuesshall be computed using the average initial cross-sectional areaof the test specimens in the calculations. The result shall beexpressed in pascals (pounds-force per square inch) andreported to thee significant figures.

11.5 Secant Modulus-At a designated strai, ths shall be

calculated by dividing the corresponding stress (nominal) bythe designated strain. Elastic modulus values are preferable and

the specimen.

11. Poisson Ratio-The axal strain, Ea' indicated by theaxial extensometer, and the transverse strai, E, indicated bythe transverse extensometers, are plotted against the applied

load as shown in Fig. 4. A straight line is drawn thougheach set of points , and the slopes dP and of theselines are determned. Poisson s ratio 1., is then calculated as

follows:

J1 (de 1 dP)/(de l dP) (1)

where:= change in transverse strain= change in axial strain, and

dP = change in applied load;

J1

= -

(de ) I (de (2)

11. 1 The errors that may be introduced by drawing astraight line though the points can be reduced by applying themethod of least squares.. 11.7 For each series of tests, calculate the arthmetic mean

of all values obtained and report it as the "average value" forthe paricular property in question.

11.8 Calculate the standard deviation (estimated) as followsand report it to two significant figures:

2 - nX2) I (n - 1) (3)

where:estimated standard deviation

= value of single observation

. D638- 02a

= number of observations , andX = arthetic mean of the set of observations.11.9 See Anex Al for information on toe compensation.

TABLE 5 Tensile Strength at Break, 10 psi , for EightLaboratories, Five Materials

Mean

Polypropylene 2.97 1.54 1.65 4.37 4.Cellulose acetate butyrate 4.82 0.058 0.180 0.164 0.509Acrylic 9.09 0.452 0.751 1.27 2.Glass-reinforced polyester 20.8 0.233 0.437 0.659 1.Glass-reinforced nylon 23.6 0.277 0.698 0.784 1.

A Tensile strength and elongation at break values obtained for unreinforced

propylene plastics generally are highly variable due to inconsistencies in neckingor "drawing" of the center section of the test bar. Since tensile strength andelongation at yield are more reproducible and relate in most cases to the practicalusefulness of a molded part, they are generally recommended for specificationpurposes.

TABLE 6 Elongation at Break, %, for Eight Laboratories, FiveMaterials

Mean

Glass-reinforced polyester 3.68 0.20 2.33 0.570 6.Glass-reinforced nylon 3.87 0.10 2.13 0.283 6.Acrylic 13.2 2.05 3.65 5.80 10.Cellulose acetate butyrate 14.1 1.87 6.62 5.29 18.Polypropylene 293.0 50.9 119.0 144.0 337.

A Tensile strength and elongation at break values obtained for unreinforced

propylene plastics generally are highly variable due to inconsistencies in neckingor "drawing" of the center section of the test bar. Since tensile strength andelongation at yield are more reproducible and relate in most cases to the practicalusefulness of a molded part, they are generally recommended for specificationpurposes.

12. 1.9 Tensile strength at yield or break, average value , andstandard deviation

12. 1. 0 Tensile stress at yield or break, if applicableaverage value, and standard deviation

12. 1.11 Percent elongation at yield, or break, or nominalstrain at break, or all three, as applicable, average value, andstandard deviation

12. 1.12 Modulus of elasticity, average value, and standarddeviation

12. 1.3 Date of test, and12. 1.4 Revision date of Test Method D 638.

13. Precision and Bias 12

13.1 Precision-Tables 6 are based on a round-robin testconducted in 1984 , involving five materials tested by eightlaboratories using the Type I specimen , all of nominal 0. 125- in.thickness. Each test result was based on five individualdetermnations. Each laboratory obtained two test results foreach material.

TABLE 8 Tensile Yield Elongation, for Eight Laboratories, EightMaterials

Test Values Expressed in Percent UnitsMaterial Speed

in.lmin Average

LOPE 17.LOPE 14. 1.02LLOPE 15.LLOPE 16.LLOPE 11.LLOPE 15. 1.27HOPE 1.40HOPE 1.23

TABLE 7 Tensile Yield Strength, for Ten Laboratories, EightMaterials

TABLE 9 Tensile Break Strength, for Nine Laboratories, SixTest Values Expressed in psi UnitsMaterialsMaterial Speed.

in.lmin AverageTest Values Expressed in psi Units

1544 52. 64. 146. 179. Material SpeedLOPE

in.lmin AverageLOPE 1894 53. 61.2 148. 171.LLOPE 1879 74. 99. 207. 279. LOPE 1592 52. 74. 146.4 209.LLOPE 1791 49. 75. 137. 212. LOPE 1750 66. 102. 186. 288.LLOPE 2900 55. 87. 155. 246. LLOPE 4379 127. 219. 355. 613.LLOPE 1730 63. 96. 178. 268. LLOPE 2840 78. 143. 220. 401.HOPE 4101 196. 371. 549. 1041.3 LLOPE 1679 34. 47. 95. 131.HOPE 3523 175. 478. 492. 1338. LLOPE 2660 119. 166. 333. 465.

12. Report

12. 1 Report the following inormation:12. 1 Complete identification of the material tested, includ-

ing type, source, manufactuer s code numbers, form, principaldimensions , previous history, etc.,

12. 1.2 Method of preparg test specimens12. 1.3 Type of test specimen and dimensions12. 1.4 Conditioning procedure used12. 5 Atmospheric conditions in test room12. 1.6 Number of specimens tested,12. 1.7 Speed of testing,12. 1.8 Classification of extensometers used. A description

of measurng technque and calculations employed instead of aminimum Class-C extensometer system

13. 1.1 Tables 7- 10 are based on a round-robin test con-ducted by the poly olefin subcommttee in 1988 , involving eightpolyethylene materials tested in ten laboratories. For eachmaterial, all samples were molded at one source, but theindividual specimens were prepared at the laboratories thattested them. Each test result was the average of five individualdetermnations. Each laboratory obtained three test results foreach material. Data from some laboratories could not be usedfor varous reasons , and this is noted in each table.

13. 1.2 In Tables 2- , for the materials indicated, and fortest results that derived from testing five specimens:

12 Supporting data are available from ASTM Headquarers. Request RR:D20-

1125 for the 1984 round robin and RR:D20- 1170 for the 1988 round robin.

,in test. eight25-in.vidualIts for

Eight

Six

09.88.13.01.31.65.

con-eighteacht the

. thatidualts forused

d for

:D20-

o D638- 02a

13. 1.2. 1 Sr is the within-laboratory standard deviation ofthe average; = 2. 83 r. (See 13. 1.2.3 for application of

13. 1.2.2 SR is the between-laboratory standard deviation ofthe average; = 2. 83 SR' (See 13. 1.2.4 for application of

13. 1.2.3 Repeatability-In comparng two test results forthe same material, obtained by the same operator using thesame equipment on the same day, those test results should bejudged not equivalent if they differ by more than the valuefor that material and condition.

13. 1.2.4 Reproducibility-In comparng two test results forthe same material, obtained by different operators using differ-

ent equipment on different days, those test results should bejudged not equivalent if they difer by more than the valuefor that material and condition. (This applies between differentlaboratories or between different equipment within the samelaboratory.

13. 1.2.5 Any judgment in accordance with 13. 1.2.3 and13. 1.2.4 wil have an approximate 95 % (0.95) probability ofbeing correct.

13. 1.2.6 Other formulations may give somewhat differentresults.

13. 1.2.7 For furter information on the methodology used inths section, see Practice E 691.

13. 1.2.8 The precision of ths test method is very dependentupon the uniformty of specimen preparation, standard prac-tices for which are covered in other documents.

13. Bias-There are no recognized standards on which tobase an estimate of bias for this test method.

and TABLE 10 Tensile Break Elongation , for Nine Laboratories, SixMaterials

icable Test Values Expressed in Percent UnitsMaterial Speed

in.!min Averageominal

567 31. 59. 88. 166.lOPE, andLDPE 569 61. 89. 172. 249.

LLDPE 890 25. 113. 71. 318.

andard LLDPE 64.4 11.7 18. 32.

LLDPE 803 25. 104.4 71. 292.

LLDPE 782 41. 96. 116. 270.

14. Keywords

14. 1 modulus of elasticity; percenttensile propertes; tensile strength

elongation; plastics;

ANNEXES

. (Mandatory Inormation)

At. TOE COMPENSATION

ALl In a typical stress-strain cure (Fig. ALl) there is atoe region AC, that does not represent a property of the

Strain

NOTE I-Some char recorders plot the mior image of this graph.FIG. A1.1 Material with Hookean Region

material. It is an arifact caused by a takeup of slack and

alignment or seating of the specimen. In order to obtain correctvalues of such parameters as modulus, strain, and offset yieldpoint this arifact must be compensated for to give thecorrected zero point on the strain or extension axis.

A1.2 In the case of a material exhbiting a region ofHookean (linear) behavior (Fig. ALl), a continuation of thelinear (CD) region of the curve is constrcted through the

zero-stress axis. Ths intersection (B) is the corrected zero-

strain point from which all extensions or strains must bemeasured, including the yield offset (BE), if applicable. Theelastic modulus can be determed by dividig the stress at anypoint along the line CD (or its extension) by the strain at thesame point (measured from Point defined as zero-strain).

A1.3 In the case of a material that does not exhibit anylinear region (Fig. A1.2), the same kind of toe correction of thezero-strain point can be made by constrcting a tangent to themaximum slope at the inflection point (H'

).

This is extended tointersect the strai axis at Point the corrected zero-strainpoint. Using Point B' as zero strain, the stress at any point (C'on the cure can be divided by the strain at that point to obtaina secant modulus (slope of Line B' C'

).

For those materials

with no linear region, any attempt to use the tangent thoughthe inflection point as a basis for determnation of an offsetyield point may result in unacceptable error.

D638- 02a

Strain

NOTE I-Some char recorders plot the mior image of ths graph.FIG. A1.2 Material with No Hookean Region

A2. DEFINTIONS OF TERMS AND SYMOLS RELATING TO TENSION TESTING OF PLASTICS

A2. elastic limit-the greatest stress whic.h a material iscapable of sustaining without any permanent strain remainingupon complete release of the stress. It is expressed in force perunit area, usually pounds-force per square inch (megapascals).

NOTE A2. Measured values of proportonal lit and elastic limitvar greatly with the sensitivity and accuracy of the testing equipment,eccentrcity of loading, the scale to which the stress-strain diagram isplotted, and oiler factors. Consequently, these values are usualy replacedby yield strengt.

A2. elongation-the increase in length produced in thegage length of the test specimen by a. tensile load. It isexpressed in units oflength , usually inches (millimetres). (Alsoknown as extension.

NOTE A2. Elongation and strain values are vald only in cases whereuniormty of specimen behavior withn the gage length is present. In thecase of materials exhbiting neckig phenomena, such values are only ofqualitative utility afer attainment of yield point. Ths is due to inability toensure that necking wil encompass the entire length between the gagemarks prior to specimen failure.

A2.3 gage length-the original length of that portion of thespecimen over which strain or change in length is determned.

A2.4 modulus of elasticity-the ratio of stress (nominal) tocorresponding strain below the proportional limit of a material.It is expressed in force per unit area, usualy megapascals(pounds-force per square inch). (Also known as elastic modu-lus or Young s modulus).

NOTE A2.3- The stress-strain relations of many plastics do not con-form to Hooke s law thoughout the elastic range but deviate ilerefromeven at stresses well below the elastic lit. For such materials the slopeof the tagent to the stress-strain curve at a low stress is usualy taken asthe modulus of elasticity. Since the existence of a tre proportionallirt

in plastics is debatable, the propriety of applying the term "modulus ofelasticity" to describe the stiffness or rigidity of a plastic has beenseriously questioned. The exact stress-strain characteristics of plasticmaterials are very dependent on such factors as rate of stressing,temperature, previous specimen history, etc. However, such a value isuseful if its arbitrar nature and dependence on time, temperature, andother factors are realized.

A2.5 necking-the localized reduction in cross sectionwhich may occur in a material under tensile stress.

A2. offset yield strength-the stress at which the strainexceeds by a specified amount (the offset) an extension of theinitial proportional portion of the stress-strain curve. It isexpressed in force per unit area, usually megapascals (pounds-force per square inch).

NOTE A2.4- This measurement is useful for materials whose stress-strain curve in the yield range is of gradual curvature. The offset yieldstrength can be derived from a stress-strain curve as follows (Fig. A2.l):

On the strain axis layoff OM equal to the specified offset.Draw OA tangent to the initial straight-line portion of the stress-strain

curve.Though draw a line MN parallel to OA and locate the intersection of

MN with the stress-strain curve.The stress at the point of intersection is the "offset yield strength." The

specified value of the offset must be stated as a percent of the original gagelength in conjunction with the strength value. Example: 1 % offset yield

strength = ... MPa (psi), or yield strength at 0. 1 % offset ... MPa (psi).

A2. percent elongation-the elongation of a test specimenexpressed as a percent of the gage length.

A2. percent elongation at break and yield:

A2. percent elongation at break-the percent elongationat the moment of rupture of the test specimen.

cO D638- 02a

----1---

/ OM = SpecifiedOffset

StrainFIG. A2.1 Offset Yield Strength

A2, percent elongation at yield-the percent elongation

at the moment the yield point (A2.21) is attained in the testspecimen.

A2. percent reduction of area (nominal)-the differencebetween the original cross-sectional area measured at the pointof rupture after breakng and afer all retraction has ceasedexpressed as a percent of the original area.

,Ius of

been

plastic

:ssing,

,lue is

, and

A2.10 percent reduction of area (true)-the differencebetween the original cross-sectional area of the test specimenand the minimum cross-sectional area withn the gage bound-ares prevailing at the moment of ruptue, expressed as apercentage of the original area.

:ction A2. 11 proportional limit-the greatest stress which amaterial is capable of sustaining without any deviation fromproportonalty of stress to strain (Hooke s law). It is expressedin force per unit area, usually megapascals (pounds-force persquare inch).

,trai)f the

It is

mds- A2.12 rate of loading-the change in tensile load caredby the specimen per unit time. It is expressed in force per unittime, usually newtons (pounds-force) per minute. The initialrate of loading can be calculated from the intial slope of theload versus time diagram.

;tress-

yield

"2. 1):

.strai

A2.13 rate of straining-the change in tensile strai perunit time. It is expressed either as strain per unit time, usuallymetres per metre (inches per inch) per minute, or percent

elongation per unit time , usually percent elongation per minute.The initial rate of straining can be calculated from the initialslope of the tensile strain versus time diagram.

NOTE A2.5- The initial rate of strainig is synonymous with the rate ofcrosshead movement divided by the initial distance between crossheadsonly in a machine with constant rate of crosshead movement and when thespecimen has a uniform original cross section, does not "neck down," anddoes not slip in the jaws.

ion of

The

I gage

yield

Isi),

imen

ation

A2.14 rate of stressing (nominal)-the change in tensilestress (nominal) per unit time. It is expressed in force per unitarea per unit time

, usually megapascals (pounds-force per

square inch) per minute. The initial rate of stressing can becalculated from the initial slope of the tensile stress (nominal)versus time diagram.

NOTE A2.6-The initial rate of stressing as determned in this mannerhas only limited physical significance. It does, however, roughly describethe average rate at which the intial stress (nomial) cared by the testspecimen is applied. It is afected by the elasticity and flow characteristicsof the materials being tested. At the yield point, the rate of stressing (tre)may continue to have a positive value if the cross-sectional area isdecreasing.

Iiiill

A2. 15 secant modulus-the ratio of stress (nominal) to

corresponding strain at any specified point on the stress-straincurve. It is expressed in force per unit area, usually megapas-cals (pounds-force per square inch), and reported together withthe specified stress or strain.

NOTE A2. This measurement is usually employed in place of modu-lus of elasticity in the case of materials whose stress-strain diagram doesnot demonstrate proportionality of stress to strain.

A2. 16 strain-the ratio of the elongation to the gage lengthof the test specimen, that is, the change in length per unit oforiginal length. It is expressed as a dimensionless ratio.

A2. 16. nominal strain at break-the strain at the momentof rupture relative to the original grp separation.

A2. 17 tensile strength (nominal the maximum tensilestress (nominal) sustained by the specimen during a tensiontest. When the maximum stress occurs at the yield point(A2.21), it shall be designated tensile strength at yield. Whenthe maximum stress occurs at break, it shall be designatedtensile strength at break.

A2. 18 tensile stress (nomina I)-the tensile load per unitarea of minimum original cross section, within the gageboundares , cared by the test specimen at any given moment.It is expressed in force per unit area, usually megapascals(pounds-force per square inch).

NOTE A2.8- The expression of tensile properties in terms of theminimum original cross section is almost universally used in practice. Inthe case of materials exhbiting high extensibility or necking, or both(A2. 15), nominal stress calculations may not be meanngful beyond theyield point (A2.21) due to the extensive reduction in cross-sectional areathat ensues. Under some circumstances it may be desirable to express thetensile properties per unit of minimum prevailing cross section. Theseproperties are called tre tensile propertes (that is, tre tensile stress, etc.

:I!

illA2. 19 tensile stress-strain curve-a diagram in which

values of tensile stress are plotted as ordinates against corre-

sponding values of tensile strain as abscissas.

A2.20 true strain (see Fig. A2.2) is defined by the follow-ing equation for E

---------_

) I

FIG. A2.2 Ilustration of True Strain Equation

,r.

D638- 02a

eT

L dUL = In . L (A2.

where:dL = increment of elongation when the distance between

the gage marks is

original distance between gage marks, anddistance between gage marks at any time.

A2.21 yield point-the first point on the stress-strain curveat which an increase in strain occurs without an increase instress (Fig. A2.2).

NOTE A2.9-Only materials whose stress-strain cures exhibit a pointof zero slope may be considered as having a yield point.

NOTE A2. 10-ome materials exhbit a distinct "break" or discontinu-ity in the stress-strain cure in the elastic region. Ths break is not a yieldpoint by definition. However, ths point may prove useful for materialcharacterization in some cases.

A2.22 yield strength-the stress at which a material exhib-its a specified limiting deviation from the proportonalty stress to strain. Unless otherwise specified, ths stress wil bethe stress at the yield point and when expressed in relation tothe tensile strength shall be designated either tensile strength atyield or tensile stress at yield as required in A2. 17 (Fig. A2.3).

(See offset yield strength.

A2.23 Symbols-The following symbols may be used forthe above terms:

Symbol

LiW

Lit

Licr

crT

crucrUT

liE

%El

TermLoadIncrement of loadDistance between gage marks at any timeOriginal distance between gage marksDistance between gage marks at moment of ruptureIncrement of distance between gage marks = elongationMinimum cross-sectional area at any timeOriginal cross-sectional areaIncrement of cross-sectional areaCross-sectional area at point of rupture measured afterbreaking specimenCross-sectional area at point of rupture, measured at themoment of rupture limeIncrement of timeTensile stressIncrement of stressTrue tensile stressTensile strength at break (nominal)Tensile strength at break (true)StrainIncrement of strainTotal strain , at breakTrue strainPercentage elongationYield pointModulus of elasticity

r--------

YIELDPOINT

L______-

A a E' TENSILE STRENGTH AT BREAIELONGATION AT BREAK

B. TENSILE STRENGTH AT YIELDELONGATION AT YIELD

C. TENSILE STRESS AT BREAKELONGATION AT BREAK

D D TENSILE STRESS AT YIELDELONGATION AT YIELD

STRAIN

FIG. A2.3 Tensile Designations

A2.24 Relations between these varous terms may bedefined as follows:

crT

crucrUT

WIA

WIA

WIA (where W is breaking load)WIA where W is breaking load)LiUL (L )/L

)/L

It. dUL In UL((L )/L x 100 = EX 100%EI

Percent reduction of area (nominal) = ((Ao - A )/ A 1 x 100Percent reduction of area (true) = ((Ao - AT)/A J x 100Rate of loading.= LiW/LiRate of stressing (nominal) = Licr/Li = (LiWj/A )/Li

Rate of straining = Lie! Lit = (LiUL )Lit

For the case where the volume of the test specimen does notchange during the test, the following three relations hold:

fYT = fY(1 + e) = fYUL (A2.

fYUT fYu (1 u IL

o /(1 + e)

BIODATA PENULIS

Nama Lengkap : Ibnu Abdil Aziz

Tempat, Tanggal Lahir : Jombang, 12 Januari 1997

Alamat Asal : Jl. Sulawesi GG.3, Plandi

Kota Jombang - Jawa Timur

Alamat di Surabaya : Jl. Bhaskara 1 no.11, Mulyorejo

Kota Surabaya – Jawa Timur

Telepon / HP : +62 823 7739 7599

Email : [email protected]

Hobi : Traveling, Jogging, Fotografi

Penulis lahir di Mojokerto pada 12 Januari 1997, anak pertama dari 2

bersaudara. Penulis telah menempuh pendidikan formal yaitu;

1. SDI Roushon FIKR

2. SMPN 2 Jombang

3. SMAN 2 Jombang

Setelah lulus SMA penulis mengikuti tes PMDK dan diterima di Politeknik

Perkapalan Negeri Surabaya (PPNS) pada tahun 2015 dan terdaftar dengan NRP.

0815040022

Pada tahun 2018 penulis mengikuti pelatihan Piping Design PDMS dan 2019

penlatihan Inspektur Pipa Penyalur di Politeknik Perkapalan Negeri Surabaya. Pada

bulan September sampai Desember 2018 penulis melaksanakan On The Job

Training (OJT) di PT. PETRO JORDAN ABADI, GRESIK. Penulis juga

menyelesaikan penelitian yang berjudul “PENGARUH HIBRID RESIN DENGAN

VARIASI SUSUNAN MAT DAN WOVEN ROVING TERHADAP

KETAHANAN KOROSI PADA FLUIDA ASAM PHOSPAT DAN KEKUATAN

TARIK”.

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