Carbon Steel Product Guide

Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. The only other alloying elements allowed in plain-carbon steel are manganese (1.65% max), silicon (0.60% max), and copper (0.60% max). Steel with a low carbon content has the same properties as iron, soft but easily formed. As carbon content rises the metal becomes harder and stronger but less ductile and more difficult to weld. Higher carbon content lowers steel’s melting point and its temperature resistance in general.

1018 Mild Steel

Alloy 1018 is the most commonly available of the cold-rolled steels. It is generally available in round rod, square bar, and rectangle bar. It has a good combination of all of the typical traits of steel – strength, some ductility, and comparative ease of machining. Chemically it is very similar to A36 Hot Rolled steel, but the cold rolling process creates a better surface finish and better properties.

1018 Mild (low-carbon) steel
Minimum Properties Ultimate Tensile Strength, psi 63,800
Yield Strength, psi53,700
Rockwell HardnessB71
ChemistryIron (Fe)98.81 - 99.26%
Carbon (C)0.18%
Manganese (Mn)0.6 - 0.9%
Phosphorus (P)0.04% max
Sulfur (S)0.05% max

A36 Mild Steel

ASTM A36 steel is the most commonly available of the hot-rolled steels. It is generally available in round rod, square bar, rectangle bar, as well as steel shapes such as I-Beams, H-beams, angles, and channels. The hot roll process means that the surface on this steel will be somewhat rough. Note that its yield strength is also significantly less than 1018 – this means that it will bend much more quickly than will 1018. Machining this material is more difficult than 1018 steel, but the cost is usually lower.

ASTM A36 Mild (low-carbon) steel
Minimum PropertiesUltimate Tensile Strength, psi58,000 - 79,800
Yield Strength, psi36,300
ChemistryIron (Fe)99%
Carbon (C)0.26%
Manganese (Mn)0.75%
Copper (Cu)0.2%
Phosphorus (P)0.04% max
Sulfur (S)0.05% max

12L14 free machining steel

This alloy has lead added to the mix in order to enhance its machinability. In fact, it is rated with a machinability of 160% of AISI 1212 steel. The addition of lead does, however, reduce the strength of this alloy, although it is generally stronger than 1018.

12L14 free machining steel
Minimum PropertiesUltimate Tensile Strength, psi 78,300
Yield Strength, psi60,200
Rockwell HardnessB84
ChemistryIron (Fe)97.91 - 98.7%
Carbon (C)0.15% max
Manganese (Mn0.85 - 1.15%
Phosphorus (P)0.04 - 0.09
Lead (Pb)0.15 - 0.35%
Sulfur (S)0.26 - 0.35%

A366/1008 Steel

This alloy is generally used for “commercial quality” cold rolled steel sheet. It is known for its very good formability and comparatively high strength. It has a very good surface finish that is far superior to hot rolled A36.

ASTM A366 (alloy 1008) steel
Minimum PropertiesUltimate Tensile Strength, psi43,900 - 51,900
Yield Strength, psi26,100 - 34,800
Elongation42 - 48%
ChemistryIron (Fe)99%
Carbon (C)0.08%
Manganese (Mn)0.6% max
Phosphorus (P)0.035% max
Copper (Cu)0.2% min
Sulfur (S)0.04%

A513 (alloy 1020-1026) Steel

This alloy is generally used for DOM tubing. Its higher carbon content means higher strength, but lower weldability and machinability.

ASTM A513 alloys 1020 - 1026 Mild (low-carbon) steel
Minimum PropertiesUltimate Tensile Strength, psi87,000
Yield Strength, psi72,000
Rockwell HardnessB89
ChemistryIron (Fe)99.08 - 99.53%
Carbon (C)0.18 - 0.23%
Manganese (Mn)0.3 - 0.6%
Phosphorus (P)0.04% max
Sulfur (S)0.05% max

Alcobra Metals states that all technical data is for comparison purposes only and is NOT FOR DESIGN. It has been compiled from sources we believe to be accurate but cannot guarantee. Please consult an Engineer.

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