This document discusses plain carbon steel, which is an iron alloy containing a maximum of 1.5% carbon. It classifies plain carbon steels as low carbon (<0.25% C), medium carbon (0.3-0.6% C), or high carbon (0.6-2% C). Low carbon steel has good ductility but low strength, while high carbon steel has high strength but low ductility. Common impurities like silicon, manganese, sulfur, and phosphorus affect the properties. The document describes the microstructure and applications of each type of plain carbon steel.

1. Babaria Institute of Technology
Topic name: - Study of Plain Carbon Steel
Subject: - Material Science & Metallurgy
Prepared By: - Hardik Sakpal (150050119096)
Branch: - Mechanical
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2.  The Primary Constituents of Plain Carbon Steel are Iron &
Carbon.
 Plain carbon steel is a type of steel having a maximum
carbon content of 1.5% along with small percentages of
silica, sulphur, phosphorus and manganese.
 They can be used successfully only if the application does
not have more strength & other engineering applications.
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3. Classification of Plain Carbon Steel
Low Carbon
Steel
Medium Carbon
Steel
High Carbon
Steel
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4. Low carbon steel
 Containing carbon up to 0.25% responds to heat treatment as improvement
in the ductility is concerned but has no effect in respect of its strength
properties.
 They are not improved in terms of strength & hardness properties by heat
due to lack of carbon.
 The microstructure of low carbon steels consists of more amounts of ferrite
& less amount of pearlite.
 They are relatively soft & weak but have extraordinary ductility &
toughness.
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5. Microstructure of low of Carbon steel
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6. Applications
 Low Carbon steels are suitable for automobile &
refrigerator bodies, cans, corrugated sheets , structural
shapes, etc.
 Their applications also include nails, nut, bolts, boiler-
plates, ship-plates, reinforcing bars, pipelines, etc.
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7. Steel nuts
Fence
Steel wires
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8. Medium carbon Steels:
 Medium carbon steels contain 0.3% to 0.6% carbon.
 They exhibit a better response to heat treatment compared to
low carbon steels.
 Their Mechanical properties can be improved by hardening
followed by tempering heat – treatments.
 By adding alloying, their ability to get hardened can be
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9. Microstructure of Medium Carbon Steel
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10. Application
Some typical applications of medium carbon steel include
gears, axels, levers, cams, bolts, sockets, screw drivers,
auger bits, cylinder liners, cylinders, hand tools, rims of
bicycle & automobile-wheels, railway car- wheels &
tracks, railways couplings, rifle barrels, balls of ball mill &
machine components.
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11. Balls of Ball Mill
Axle
Rims of bicycle
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12. High Carbon Steels
 High carbon steels contain carbon from 0.6% to 2%.
 They are hardest and strongest among plain carbon steels but least ductile.
 They have poor formability, machinability & weldability as compared to
medium carbon steel; but good hardenability.
 The alloying elements such as tungsten, molybdenum, chromium &
vanadium can be added in these steels to form hard & wear resistant
carbide compounds. Such high carbon steels with carbide compounds can
be used for making tools & dies.
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13. Microstructure of High Carbon Steel
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14. Application
The typical applications of high carbon steels include
lock washers, valve springs, wrenches, cutting tools,
dies, shearing knives, anvils, chisels, hammers, milling
cutters, tapes, razors, hacksaw blades, piston rings &
gauges.
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15. Lock Washers
Valve Springs
Wrenches
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16. Effect of impurity elements on
properties of plain carbon steels
 There are four common impurity elements in plain carbon
steels
a. Silicon
b. Manganese
c. Sulphur
d. Phosphorus.
 The properties of plain carbon steels primarily depend upon
the carbon content & to a large extent upon these four impurity
elements.Bits edu Campus 16

17. Silicon
 Its content in plain carbon steel varies from 0.05% to 0.30% .
 It is a good strengthened of ferrite in steels.
 It increases strength, hardness & toughness without loss of
ductility.
 It is strong deoxidizer and removes dissolved gases & oxidizes
during solidification of steel.
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18. Manganese
 The manganese content in plain carbon steel varies from 0.3% to
1.0%.
 It decreases the harmful effect of sulphur, i.e. brittleness at high
temperature by forming MnS thereby reducing content of FeS.
 It increases the hardenability of the steel.
 It dissolves in ferrite 7 increases yield strength, tensile strength,
toughness & ductility considerably.
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19. Sulphur
 Normally, sulphur content in the steel should be allowed to exceed
0.05%.
 The inclusions of FeS soften & may melt at rolling or forging
temperatures reducing the tenacity of the hot metal & sometimes causing
disintegration by cracking in the rolls or under the hammer.
 This is called as hot shortness or hot embrittlement.
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20. Phosphorus
 The maximum content of phosphorus does not exceed 0.04%.
 Phosphorus dissolves in ferrite, increasing strength, hardness
& improving the resistance to corrosion. So, it is added to low
carbon steels up to 0.12%.
 It is added to improve machinability of certain grades of free
cutting steels up to a maximum content of 0.12%.
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21. Limitations of Plain Carbon Steel
I. The strength of plain carbon steels cannot be increased beyond 700 Mpa
without substantial loss in ductility & impact strength.
II. They have poor impact strength at low temperatures.
III. They have poor corrosion resistance & oxidation resistance.
IV. Properties do not remain uniform for larger thickness of plain carbon
steels.
V. They are not deep hardenable.Bits edu Campus 21

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