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Carbon steels

Dr. Dmitri Kopeliovich

Carbon steels are iron-carbon alloys containing up to 2.06% of carbon, up to 1.65% of manganese, up to 0.5% of silicon and sulfur and phosphorus as impurities.

Carbon content in carbon steel determines its strength and ductility.

The higher carbon content, the higher steel strength and the lower its ductility.

According to the steels classification there are following groups of carbon steels:

Designation system of carbon steels
Chemical compositions of some carbon steels
Properties of some carbon steels

Low carbon steels (C < 0.25%)

Properties: good formability and weldability, low strength, low cost.

Applications: deep drawing parts, chain, pipe, wire, nails, some machine parts.

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Medium carbon steels (C =0.25% to 0.55%)

Properties: good toughness and ductility, relatively good strength, may be hardened by quenching

Applications: rolls, axles, screws, cylinders, crankshafts, heat treated machine parts.

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High carbon steels (C > 0.55%)

Properties: high strength, hardness and wear resistance, moderate ductility.

Applications: rolling mills, rope wire, screw drivers, hammers, wrenches, band saws.

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Tool carbon steels (C>0.8%) – subgroup of high carbon steels

Properties: very high strength, hardness and wear resistance, poor weldability low ductility.

Applications: punches, shear blades, springs, milling cutters, knives, razors.

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Designation system of carbon steels

American Iron and Steel Institute (AISI) together with Society of Automotive Engineers (SAE) have established four-digit (with additional letter prefixes) designation system:

SAE 1XXX

First digit 1 indicates carbon steel (2-9 are used for alloy steels);

Second digit indicates modification of the steel.

0 - Plain carbon, non-modified

1 - Resulfurized

2 - Resulfurized and rephosphorized

5 - Non-resulfurized, Mn over 1.0%

Last two digits indicate carbon concentration in 0.01%.

Example: SAE 1030 means non modified carbon steel, containing 0.30% of carbon.

A letter prefix before the four-digit number indicates the steel making technology:

A - Alloy, basic open hearth

B - Carbon, acid Bessemer

C - Carbon, basic open hearth

D - Carbon, acid open hearth

E - Electric furnace

Example: AISI B1020 means non modified carbon steel, produced in acid Bessemer and containing 0.20% of carbon.

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Chemical compositions of some carbon steels

SAE/AISI grade C, % Mn,% P,% max S,% max
1006 0.08 max 0.35 max 0.04 0.05
1010 0.08-0.13 0.30-0.60 0.04 0.05
1020 0.17-0.23 0.30-0.60 0.04 0.05
1030 0.27-0.34 0.60-0.90 0.04 0.05
1045 0.42-0.50 0.60-0.90 0.04 0.05
1070 0.65-0.76 0.60-0.90 0.04 0.05
1090 0.85-0.98 0.60-0.90 0.04 0.05
1117 0.14-0.20 1.10-1.30 0.04 0.08-0.13
1547 0.43-0.51 1.35-1.65 0.04 0.05


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Properties of some carbon steels

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carbon_steels.txt · Last modified: 2023/12/13 by dmitri_kopeliovich
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