PENGARUH LINGKUNGAN KOROSIF TERHADAP LAJU KOROSIPADA PIPA MINYAK DAN GAS

Oleh: Aulia Rahman ( 05510089 )

Electrical Engineering Dibuat: 2008-02-23 , dengan 3 file(s).

Keywords: Lingkungan, tingkat korosi, pipa minyak dan gas

Abstraksi

Akhir-akhir ini sering terjadi kebocoran instalasi pipa minyak dan gas seperti kasus kebocoran pipa lapindo disidoarjo 2006 lalu; kebocoran pipa minyak PT Midco E&T di Muara

Enim- Sumatra Selatan 10 Mei 2005; kebocoran pipa di Pembangkit Listrik Tenaga Gas dan Uap Sicanang Belawan-Medan. Kebocoran tersebut bisa disebabkan banyak faktor yang

dikelompokan atas faktor teknis (kesalahan manusianya) dan nonteknis (akibat faktor alam). Faktor teknis

misalnya akibat kelalaian manusia dalam proses pengerjaan sehingga menyebabkan cacat pada instalasi pipa

sehingga berpotensi pada kebocoran, dan nonteknis yaitu korosi. Penyambungan logam dengan sistem pengelasan banyak digunakan. Pada pengelasan, biaya

murah, pelaksanaan relative lebih cepat, lebih ringan, dan bentuk konstruksi lebih variatif. Sambungan las juga memiliki kelemahan; timbulnya lonjakan tegangan yang besar disebabkan oleh

perubahan struktur mikro pada daerah sekitar las yang menyebabkan turunnya kekuatan bahan dan akibat

adanya tegangan sisa, serta adanya retak akibat dari proses pengelasan. Berangkat dari kenyataan diatas, maka itu perlu penelitian lebih lanjut mengenai hal-hal tersebut

sehingga didapat dalil yang dapat dipertanggung jawabkan. Dan dapat dijadikan acuan dalam proses

coating (pelapisan) atau perencanaan ketahanan korosi, karena penelitian ini merupakan diagnosa serangan korosi yang rentan terhadap spesimen

Metal join with weld system use often. In weldment, have save cost, relative ly fast work,

more light, and variety construct. Weldment have weakness is appear of strain that big cause of differences microstructur on weld zone that metal strength down and cause residual stress, and crack

cause weldment. The point of this experience worked is want to know influence of corrosive environment that

give at corrosion rate in experiment specimen. And to know forms of exposure corrosion that happen from rate corrosion that result. Then to know micro corrosion that happen in specimen that weld

(weld

metal, heat affected zone, and base metal). Endly can be recommendation in coating process or corrosion resistant plant because this experiment is diagnose corrosion attack that susceptible in

speciment. In this experiment, have experiment methode, that each specimens group exposed in

environment that digerences is NaCl 10%, H 2 SO 4 10%, and moist environtment, until hour 168. Then test measure rate corrosion, then test micro corrosion dan macro corrosion that happen as

influence environments its in speciment IRON API5L-X52 that weld. The results, forms of corrosion that happen on specimen is in moist environment is uniform

corrosion that thin (corrosion rate = 0), on expose environment NaCl 10% liquid is uniform corrosion that thick and pitting corrosion (corrosion rate = 2,036 Mpy), then on expose environment

H2 SO 4 10% is happen uniform corrosion and pitting corrosion that more thick (corrosion rate = 53,041 Mpy).

Form of micro corrosion that happen is selective leaching corrosion (in Base Metal, Weld Metal, and Heat Affected Zone). Zone that more corrosion attack is HAZ (10,797 %) as result thermal strain

from weld thermal influence, then BM zone (8,978 %) result oxidation on exposure cause lost of

shield elements and on corrosion resitant reduce, then WM zone (5,94 %) is influence of weld process, and

because chemistry property that more better in shield of corrosion and compensation from residual

stress.