ENGINEERING MATERIALSA material either in solid form or other condensed phases are
defined as any substance that is projected for use for definite
application. Materials can be found all around us that are from
earth’s crust or in anything from building to spacecraft.
Crystalline and Non- Crystalline are to categories that can be
used to classify the materials. Metals, ceramics and polymers are
some examples of traditional materials and on the other hand semi
conductors, nano-materials and bio- materials are some examples of
advanced materials. In the earth’s crust, iron is the most common
element and nearly every construction undertaken there is at least
a little use of iron. Iron is considered as a chemical element and
in the periodic table it can be located with a symbol Fe with an
atomic number 26. Iron ore through several processes can be
converted into various types of iron and on of this is steel. The
other type of material that had been used over centuries is
ceramic. Ceramic is derived from common, naturally raw materials
such as clay and quartz sand. Some of the products made from
ceramics that are familiar to us are china tableware, clay brick
and tiles, clay pots and porcelain flower vases. In this
assignment, I will look into how two such materials, steel and
porcelain, are manufactured, the raw materials used, their
properties, sustainability and its application.
Firstly, the raw materials used to manufacture these materials
are as follows: Steel, the raw materials used are iron ore, coal,
limestone and recycled steel.
The primary components used for porcelain are clay, feldspar or
flint and silica
These are the raw materials that are blended together to
manufacture the materials such as steel and porcelain.
Secondly, will know look at how these various raw materials are
processed to create the useful materials, in the other words the
manufacturing process. Now looking into how steel is manufactured:
The iron ore are crushed and sorted so that only the best grades
of iron ore are introduced in the blast furnace (tower shaped
structure with its interior is made of steel and fitted with heat
resistant bricks) together with limestone and coke. A very hot air
is blown through the use of nozzle situated at the bottom of the
furnace. There is formation of carbon monoxide in the furnace as
the coke burns in the presence of hot air reacting with oxygen.
Reaction of iron ore and carbon monoxide results in formation of
carbon dioxide and pure iron.
Picture of a Blast Furnace
The following chemical reactions take place in the blast furnace
that enables the formation of carbon dioxide and pure iron.
The molten iron from the blast furnace is than poured into an
upright cylindrical vessel, shown in the picture below (figure 1).
Pressurized oxygen gas is introduced on top of the molten metal.
The impurities present in the iron such as manganese, phosphorus,
silicon and excess carbon reacts with the oxygen and forms slag
After this process, the molten steel settles below in the vessel
and the slag floats on top of the vessel. The vessel is rotated
horizontally so that the molten steel can be tapped off (as
illustrated in Figure 2). The molten steel is than processed
through continuous casting processes by machines to produce
stainless steel slabs (as shown in figure 3 & 4). These slabs go
through a surface grinding process so that all the uneven surface
and defects are removed.
Figure 1: Cylindrical Vessel
Temperature
Reaction
At 500 °C
3Fe2O3 +CO → 2Fe3O4 + CO2
Fe2O3 +CO → 2FeO + CO2
At 850 °C
Fe3O4 +CO → 3FeO + CO
At 1000 °C
FeO +CO → Fe + CO2
At 1300 °C
CO2 + C → 2CO (formation of carbon monoxide)
At 1900 °C
C+ O2 → CO2 ( production of carbon
dioxide)
FeO +C → Fe + CO (iron and carbon dioxide is produced)
Thirdly, porcelain is another material that is widely used in the
engineering material. Manufacturing of porcelain, the raw
materials such as clay, feldspar and silica are carried out as
follows:
A. Crushing
Reduction of raw material to desired size is achieved by
using jaw crushers (using swinging metal jaws). Than it is
further reduced in size by use of hammer mills (steel –tired
wheels, rapidly moving steel hammers). To achieve very fine
particles, ball mills filled with spherical shaped steel or
ceramic grinding media are used.
B. Cleaning and Mixing
The ingredients after the breakdown, passes through a series
of screens so that undesired sized materials are removed. It
is then mixed with water, for this produces the preferred
texture. A magnetic filtration is carried out to remove the
iron from the slurries.
C. Forming Body
The porcelain body is formed by either of the methods:
Soft plastic forming – manual molding of clay shapes is
by the use of wheel throwing. The desired amount of clay
is placed on the wheel and shaped as the wheel spins.
Jaw
crushersHammer Ball mills Grinding
Stiff plastic forming – use of a steel die through which
the body is forced that enables to form a column of
uniform girth.
Pressing – this method compacts and shape dry bodies in
rigid die or flexible mold.
Slip Casting – slurry is poured into a porous mold of
the desired shape.
D. Bisque-firing – after the shape is formed, the porcelain
parts are exposed to a low temperature to vaporize volatile
contaminants and also minimize shrinkage.
E. Glazing – proper coating is applied to the porcelain ware by
means of painting, pouring, dipping or spraying.
F. Firing – a kiln or oven is used to heat the porcelain ware so
that it is hardened and produces irreversible changes in the
product made.
After the completion of all this manufacturing process than only
the final product is achieved that is of high quality and
marketable.
In addition, the material poses certain property that enables it
to perform well in the required engineering application. The
properties are tabulated as follows:
STEELPhysical Mechanical Unique PropertiesStrength Toughness High Impact Strength Stain resistant Ductility Resistance to abrasionNon conductive Durability Self ProtectiveHygienic Weld ability Simple to use High Tensile StrengthMalleability High Modulus of
Elasticity
PORCELAIN
Physical Mechanical Unique PropertiesSpecific gravity Hardness Color PerformanceThermal conductivity Abrasion and Wear
ResistanceColor Availability
Flexural Strength Lubricity Gloss Compressive Strength Adhesion Light ReflectanceMaximum Operating Temperature
Impact Resistance Texture
Tensile Strength Flexibility Clean ability Thermal Expansion
Furthermore, the sustainability of the material is also important
that is the recyclability, energy to produce the product, impact
on human and environment. Therefore, looking at steel it is not
harmful to people, low maintenance cost, long life due to high
corrosion resistance, uses fewer resources to manufacture and can
be easily recycled ( the scrap that is not recycled, turns into
iron oxide and returns to the ground so it can be said that steel
is sustainable. On the other hand, porcelain is also sustainable
because it is eco-friendly; material extraction is cheap because
the raw materials are close to the proximity; it does not emit or
absorb pollutants and it can be recycled easily by mixing it with
water and the waste can be used for production process.
Lastly, the application of the two types of material; steel and
porcelain. The application of the material is tabulated as
follows:
STEEL APPLICATION CAN BE CLASSIFIED INTO FIVE GROUPS:a. Transportb. Construction c. Energy d. Packaging e. Appliances and Industry
PORCELAIN IS MOSTLY USED FOR:a. Utilitarian Waresb. Artistic Objectsc. House Waresd. Decorative Itemse. Laboratory Equipmentf. Kitchen and Bathroom Wareg. Electrical Insulating Materialh. Building Material- tiles and panels
In conclusion, engineering materials are very important towards
the growth of the advancing era of technology. Most of the raw
materials to process and manufacture these materials are naturally
available and are carefully selected for the desired application.
It could be seen that the raw materials undergo several processing
stages before it is ready to be molded into final products such as
crushing, heating, casting, molding, various bonding stages and
polishing. The materials have physical, mechanical, chemical and
electrical properties that make it unique for its desired use.
Apart from these, the materials should be sustainable in regards
to environment, humans, energy produced and recyclability. The
materials should also be applicable to various uses such as
industrial, construction, electrical and transport.
BIBLIOGRAPHY
Advanced Engineering Materials - Wiley Online Library
http://onlinelibrary.wiley.com/doi/10.1002/(ISSN)1527-2648/home
Materials Science and Engineering : A - ScienceDirect.com
http://www.sciencedirect.com/science/journal/09215093
The Manufacture of Steel
http://nzic.org.nz/ChemProcesses/metals/8A.pd
Manufacturing Process for Iron and Steel
http://www.jfe-21st-cf.or.jp/chapter_2/2a_1.html
How porcelain is made - material, making, used, processing
http://www.madehow.com/Volume-1/Porcelain.htm
Chapter 6. Mechanical Properties of Metals
http://www.virginia.edu/bohr/mse209/chapter6.htm
MARKING CRITERIA FOR THIS ASSIGNMENT 2
Name: ________________________ I.D No. ____________________________
PART A Excellent(4) Proficient(3) Average(2) Poor(1) A Coverage of
terms of reference
All terms of reference met with detailed appropriate analysis
All terms of reference met
Most terms of reference met
Few terms of reference met
B Introduction Introduction clearly establish context
Introduction clearly establish some context
Introduction attempts to establish context
Introductionfails to establish context
C Materials and Methods:
Precisely and clearly outlined the method; reported the detailed proceduresof the study; specified the use of the two materials in details
Clearly outlined the method; reported the procedures of the study but a few points were not detailed enough; mentioned most of the two materials
Briefly outlined the method; brieflydescribed the procedures; only mentioned one material
Briefly outlined the method; procedures ofthe study were described ambiguously
D Content:
All content directly related tothe topic.
Content directly related to the topic.
Demonstrated Basic understanding of the topic
Few facts related to the topic.
E Visuals Visuals were clear,simple, accurate, titled & sourceslabelled
Visuals were simple and clear but some labels & sources were missed
Visuals were not labelled and sources in details
No Visuals
F Background: Provided a very comprehensive and detailed background; a wide and deep coverage of the topic
Showed a detailedbackground but not comprehensive enough; sufficiently covered the work but a few areas notdeep enough
A background with basic information; some key pointsmissed; coveredthe topic at ageneral level
Lacked of significant details in the topic
G Organisation Well organised Thoughtfully Somewhat Irregular and
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