3. Industrial materials are substances employed in industrial processes for the creation of goods and artifacts.
Materials may be classified in different ways: nature of constituents, usage, etc. In general, they are classified
as metals and non-metals.
Most metals are solids at room temperature and exist as crystal lattices with atoms
held together by strong metallic bonds.
Metals are grouped into ferrous and non-ferrous materials.
Metals can further be classified as plain or alloy metals. Plain metals are materials that have a significant composition
of a base element but contain traces of other elements mainly as impurities.
Alloy metals are materials that have one or more base elements but contain significant amount of other elements
that are used to impact specific properties.
That is, for some metals, mechanical, chemical, electrical, etc., properties can be modified by
adding alloys.
An alloy is an element added to a base material so as to modify the properties of the base
material.
An alloyed material is a uniform mixture of the base and alloying substances. Metals usually have
high melting point, are relatively ductile and malleable, and are hard with relatively high tensile strength.
They are often good conductors of heat and electricity with high densities.
o Exceptions include mercury which is liquid at room temperature with a melting point of -39 oC. Sodium and potassium
are light and soft with melting points of 97 oC and 63 oC respectively.
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4. Industrial materials are substances employed in industrial processes for the creation of goods and artifacts.
Materials may be classified in different ways: nature of constituents, usage, etc. In general, they are classified
as metals and non-metals. Cont.…
Metals are used in two forms of castings and wrought metals
Casting is used to produce ingots or component blanks.
The component blanks or work pieces are processed into finished forms by secondary manufacturing
processes.
Ingots are used as stock materials for producing wrought metals which are obtained by some
secondary manufacturing processes such as forging, rolling, and extrusion.
Practically all metals, which are not used in cast form or component blank, are reduced to some standard shapes for
subsequent processing.
Ingots are obtained by casting liquid metal into rectangular and square cross-sections. The section may be in
form of a slab, billet, or bloom.
Sometimes continuous casting methods are also used to cast the liquid metal
into slabs, billets or blooms.
Slabs measure 500-1800 mm wide and 50-300 mm thick. Billets measure 40x40
to 150x150 sq. mm, and blooms measure 150x150 to 400x400 sq. mm.
These shapes are further processed
through hot rolling, forging or extrusion, to produce materials in standard form such as plates, sheets, rods,
tubes and structural sections.
5. Industrial materials are substances employed in industrial processes for the creation of goods and artifacts.
Materials may be classified in different ways: nature of constituents, usage, etc. In general, they are classified
as metals and non-metals. Cont.…
Non-metals exist as covalent molecules where atoms are held together by weak forces.
Non-metals usually have low melting point, are relatively brittle and soft with relatively low tensile strength.
They are often bad conductors of heat and electricity with low densities. Exceptions include carbon which is extremely
hard with high melting temperature when in the form of diamond and is a good conductor of heat and electricity
when in the form of graphite.
8. Extrusion Process Products: Steel Pipes and Tubes
Extrusion Process : something that has been shaped by being forced through a die:
Die casting is a metal casting process that is characterized by forcing molten metal
under high pressure into a mould cavity. The mold cavity is created using two
hardened tool steel dies which have been machined into shape and work similarly to
an injection mold during the process
10. FERROUS MATERIALS
Ferrous materials have iron as base or main constituent. They include iron, steel and
their alloys. For example,
1. Pig iron has iron content of 91% to 99% and carbon content of 3.5% to 4.5%.
Pig iron is the product of smelting iron ore (also ilmenite) with a high-carbon fuel and reductant such as coke,
usually with limestone as a flux. Charcoal and anthracite are also used as fuel and reductant. Pig iron is produced
by smelting or iron ore in blast furnaces or by smelting ilmenite in electric furnaces
11. FERROUS MATERIALS
Ferrous materials have iron as base or main constituent. They include iron, steel and
their alloys. For example,
2. Carbon steel has iron content of 98.1% to 99.5% and carbon content of 0.07% to 1.5%.
Carbon steel is an iron-carbon alloy, which contains up to 2.1 wt.% carbon. For carbon steels, there is no minimum
specified content of other alloying elements, however, they often contain manganese. The maximum manganese,
silicon and copper content should be less than 1.65 wt.%, 0.6 wt.% and 0.6 wt.%, respectively
Types of carbon steel and their properties
Carbon steel can be classified into three categories according to its carbon content:
1. low-carbon steel (or mild-carbon steel),
2. 2. medium-carbon steel and
3. 3. high-carbon steel follows:
12. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Their carbon content, microstructure and properties compare as follows:
Low-carbon steel
Low-carbon steel is the most widely used form of
carbon steel. These steels usually have a carbon
content of less than 0.25 wt.%. They cannot be
hardened by heat treatment (to form martensite)
so this is usually achieved by cold work.
Carbon steels are usually relatively soft and have
low strength. They do, however, have high
ductility, making them excellent for machining,
welding and low cost.
High-strength, low-alloy steels (HSLA) are also often classified as low-carbon steels, however, also contain other elements such as copper,
nickel, vanadium and molybdenum. Combined, these comprise up to 10 wt.% of the steel content. High-strength, low-alloy steels, as the
name suggests, have higher strengths, which is achieved by heat treatment. They also retain ductility, making them easily formable and
machinable. HSLA are more resistant to corrosion than plain low-carbon steels.
13. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Low-carbon steel Products
Low carbon steel is generally not heat treated before use, and is generally rolled into angle steel, channel steel, I-
beam, steel pipe, steel strip or steel plate for making various building components, containers, boxes, furnace bodies
and agricultural machinery.
Between 400 – 550 MPa
14. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Their carbon content, microstructure and properties compare as follows:
Medium-carbon steel
Medium-carbon steel has a carbon content of 0.25 – 0.60 wt.% and a manganese content of 0.60 – 1.65 wt.%. The
mechanical properties of this steel are improved via heat treatment involving autenitising followed by quenching
and tempering, giving them a martensitic microstructure.
Heat treatment can only be performed on very thin sections, however, additional alloying elements, such as
chromium, molybdenum and nickel, can be added to improve the steels ability to be heat treated and, thus,
hardened.
Hardened medium-carbon steels have greater strength than low-carbon steels, however, this comes at the expense
of ductility and toughness. ( for machining, it has a risk…due to its carbon content…)
15. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Medium-carbon steel
Medium carbon steel products are often found as manufactured automotive parts like axles, crankshafts, couplings,
forgings, and chassis. They provide stability to vehicle engines, as well as, improve upon safety and performance.
620 Mpa yeilds
16. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Their carbon content, microstructure and properties compare as follows:
High-carbon steel
High-carbon steel has a carbon content of 0.60– 1.25 wt.% and a manganese content of 0.30 – 0.90 wt.%. It has the
highest hardness and toughness of the carbon steels and the lowest ductility. High-carbon steels are very wear-
resistant as a result of the fact that they are almost always hardened and tempered.
Tool steels and die steels are types of high-carbon steels, which contain additional alloying elements including
chromium, vanadium, molybdenum and tungsten. The addition of these elements results in the very hard wear-
resistant steel, which is a result of the formation of carbide compounds such as tungsten carbide (WC).
17. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Their carbon content, microstructure and properties compare as follows:
High-carbon steel
High carbon steel is better for structural applications, such as in heavy-duty parts. For example, AISI 1095 is a type
of high carbon steel with high hardness and wear resistance, it’s often used for knives and daggers. Manganese
steel is also less brittle than carbon steel.
Ultimate Tensile strength =685 MPa
18. FERROUS MATERIALS
Types of carbon steel and their properties cont.…
Their carbon content, microstructure and properties compare as follows:
High-carbon steel AISI SAE 1095 product sample.
which can be used as tool steel, blade steel,
spring steel. 1095 high carbon steel uses
mainly include chef knife, kitchen knife,
pocket knife, mower knives, Bowie knife,
hunting knife, doctor blade, wear parts,
various springs, plow beams, ploughshares,
scraper blades, and brake discs.
steel billets steel powder
19. FERROUS MATERIALS
Production and processing
Carbon steel can be produced from recycled steel, virgin steel or a combination of both.
Virgin steel is made by combining iron ore, coke (produced by heating coal in the absence of air) and lime in a blast
furnace at around 1650 °C. The molten iron extracted from the iron ore is enriched with carbon from the burning
coke. The remaining impurities combine with the lime to form slag, which floats on top of the molten metal where
it can be extracted.
The resulting molten steel contains roughly 4 wt.% carbon. This carbon content is then reduced to the desired
amount in a process called decarburisation. This is achieved by passing oxygen through the melt, which oxidises the
carbon in the steel, producing carbon monoxide and carbon dioxide.
20. FERROUS MATERIALS
Examples & Applications
Low-carbon steel are often used in automobile body components, structural shapes (I-beams, channel
and angle iron), pipes, construction and bridge components, and food cans.
Medium-carbon steel As a result of their high strength, resistance to wear and toughness, medium-
carbon steels are often used for railway tracks, train wheels, crankshafts, and gears and machinery parts
requiring this combination of properties.
High-carbon steel Due to their high wear-resistance and hardness, high-carbon steels are used in cutting
tools, springs high strength wire and dies.
21. FERROUS MATERIALS
Type
AISI/ASTM
name
Carbon
content
(wt.%)
Tensile
strength
(MPa)
Yield
strength
(MPa)
Ductility (%
elongation
in 50 mm)
Applications
Low 1010 0.1 325 180 28
Automobile panels,
nails, wire
Low 1020 0.2 380 205 25
Pipes, structural steel,
sheet steel
Low A36 0.29 400 220 23 Structural
Low A156-Grade 70 0.31 485 260 21
Low-temperature
pressure vessels
Medium 1030 0.27 – 0.34 460 325 12
Machinery parts, gears,
shifts, axles, bolts
Medium 1040 0.37 – 0.44 620 415 25
Crankshafts, couplings,
cold headed parts.
High 1080 0.75 – 0.88 924 440 12 Music wire
High 1095 0.90 – 1.04 665 380 10 Springs, cutting tools
Comparison of properties and applications of different grades
Examples, properties, and applications of the various carbon steels are compared in the following table.
23. FERROUS MATERIALS
Ferrous materials have iron as base or main constituent. They include iron, steel and
their alloys. For example,
Wrought iron has iron content of 99% to 99.8% and carbon content of 0.05% to 0.25%. These materials usually
have some traces of manganese, Sulphur, phosphorus, and silicon
Wrought iron is magnetic, corrosion-resistant and easily welded. It has high elasticity and tensile strength. It
can be heated and reheated and worked into various shapes
24. Wrought Iron
Ferrous materials have iron as base or main constituent. They include iron, steel and
their alloys. For example,
Wrought iron has iron content of 99% to 99.8% and carbon content of 0.05% to 0.25%. These materials usually
have some traces of manganese, Sulphur, phosphorus, and silicon
Wrought iron is magnetic, corrosion-resistant and easily welded. It has high elasticity and tensile strength. It
can be heated and reheated and worked into various shapes
Wrought iron is an iron alloy with very low carbon content (less than 0.08%) with respect to cast iron (2.1%
to 4%). The microstructure of wrought iron shows dark slag inclusions in ferrite.
It is soft, ductile, fibrous variety that is produced from a semifused mass of relatively pure iron globules
partially surrounded by slag. It usually contains less than 0.1 percent carbon and 1 or 2 percent slag.
Wrought iron is magnetic, corrosion-resistant and easily welded.
It has high elasticity and tensile strength
It can be heated and reheated and worked into various shapes. Wrought iron is no longer produced on a
commercial scale. The modern functional equivalent of wrought iron is mild steel, also called low-carbon
steel. Many products described as wrought iron, such as guard rails, garden furniture and gates, are actually
made of mild steel. For example, the Eiffel Tower is a wrought-iron lattice tower.
26. Ferrous Material : Cast Iron
Ferrous iron materials include pig iron, cast iron, and wrought iron. Cast iron can further be classified
into :
1. gray cast iron Grey cast iron is a ferrous alloy which has been heated until it liquefies and is then
poured into a mould to solidify. Grey cast iron, or grey iron, has graphitic flakes which deflect a
passing crack and initiate countless new cracks as the material breaks.
2. white cast iron White cast irons are hard and brittle; they cannot easily be machined.
White cast iron has a light
appearance due to the
absence of graphite.
27. Ferrous Material : Cast Iron
Ferrous iron materials include pig iron, cast iron, and wrought iron. Cast iron can further be classified
into :
3. chilled cast iron Chilled Cast Iron White cast iron is made by quenching hot metal. Quenching is
commonly called quenching, and cast iron produced in this way is called chilled cast iron. All castings
are skin cooled by the contact of molten iron with cold sand in the mold.
4. ductile and malleable cast iron
small amounts of magnesium is added. Ductile
iron is very similar to malleable iron, but parts
can be cast larger compared to malleable iron
where there is a limit of how large the part
sections can be cast.
28. Assignment :
1.Comparison between wrought iron, steel and cast iron
2.Common metals and their alloys found on our daily living and
its application
3. Explore on the material code shown.
