ASTM A572/A572M — Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel
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Scope
HSLA structural shapes, plate, sheet piling and bar in Grades 42, 50, 55, 60 and 65 (290–450 MPa yield) micro-alloyed with niobium (columbium) and/or vanadium (Types 1–5). Thickness limits per grade; supplementary S5 (Charpy), S90/S91 (CE), S32 (fine grain). Adopted as SA-572 by ASME; A709 Grade 50 and A992 are the bridge and W-shape derivatives.
Grades covered by ASTM A572
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| A572 Grade 50 | K02303 | High-strength low-alloy (HSLA) columbium-vanadium structural steel | ≤ 0.23 | 290 | ≥ 415 | S355JR / S355J2, S355M / S355N, A992 |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1966 | A572 first issued (Grades 42–65) |
| 1989 | Replaced A441 Mn-V steel |
| 2021 | A572/A572M-21 — current |
Supersedes: ASTM A441 (withdrawn 1989).
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Related standards
Grade is the yield in ksi
A572 covers high-strength low-alloy columbium-vanadium structural steel, and the grade number is the minimum yield strength in ksi: Grade 42, 50, 55, 60 and 65 correspond to 290, 345, 380, 415 and 450 MPa. Grade 50 carries almost all of the volume.
The strength comes from microalloying with niobium (columbium in American usage) and vanadium rather than from carbon, so the carbon ceiling stays low — 0.23 % for Grade 50 — and weldability is better than the strength alone would suggest. That is the whole design of the specification.
A572, A992 and A709 are close relatives
Three specifications overlap at 345 MPa and are not the same order. A572 Grade 50 is the general HSLA structural steel across plate, shapes and bar. A992 is specific to wide-flange shapes, adds a yield *ceiling* of 450 MPa and a yield-to-tensile ratio limit, and is what a US building specification normally calls for in beams. A709 is the bridge specification, which adds mandatory impact testing by climatic zone.
Material certified to A992 usually satisfies A572 Grade 50; the reverse does not hold, because A572 sets no upper limit on yield.