ASTM A36 is the most widely used structural carbon steel specification in the world. It covers carbon steel shapes, plates and bars for general structural use, and it is the default grade on most steelwork drawings unless something stronger, tougher or weld-critical is called for.
What the specification fixes
- Minimum yield strength 250 MPa (36 ksi), with tensile strength 400–550 MPa.
- Chemistry — carbon up to about 0.26 %, manganese 0.80–1.20 % on shapes and plates over 20 mm, silicon 0.15–0.40 %.
- Forms covered — plates, bars, shapes and sheet piling.
- Weldability — the low carbon and moderate manganese are what make A36 the easy grade to weld.
What A36 is not
A36 is not a pressure vessel steel, it is not specified for low-temperature toughness, and it is not a high-strength grade. Above about 20 mm the yield requirement does not scale with section, which is why heavier structures move to A572 or A992. For pressure service the equivalent conversation is about A516, not A36.
Download the standard
ASTM A36/A36M — Standard Specification for Carbon Structural Steel (PDF)
Related reading
- ASTM A29 — the general bar requirements A36 bars are ordered against.
- ASTM A108 — the cold finished version of the same carbon steel bar.
- AISI 1045 carbon steel — the medium-carbon grade used when A36 is not strong enough.
- Standards library — every specification we supply against, in one index.
