By Brock Cooper
Updated Aug 30, 2022
The American Society for Testing and Materials (ASTM) and the American Society for Civil Engineers (ASME) each publish steel standards that are often similar, but they can diverge on specific criteria. When comparing the ASTM A36 and ASME SA36 grades, the differences are subtle yet significant for certain applications.
ASTM A36 defines carbon steel plates, bars, and shapes up to 8 inches thick with a minimum yield strength of 36,000 psi. It is widely used across construction, fabrication, and general structural applications. The standard explicitly excludes advanced alloy steels, focusing solely on plain‑carbon material.
ASME SA36 is derived from the ASTM A36 specification but expands its scope to cover all carbon steel components used in bridge construction, pressure vessels, and boiler systems. It incorporates the ASTM yield and tensile strength requirements while adding the rigorous boiler and pressure vessel criteria mandated by ASME.
While the mechanical properties (yield strength, tensile strength, chemical composition) are largely identical, SA36 steel must also satisfy the pressure‑vessel standards that A36 does not. Consequently, every SA36 plate or bar meets the ASTM A36 requirements, but not every A36 component is suitable for pressure‑vessel service.
A36 steel is the go‑to material for building frames, bridge decks, and structural steelwork where its strength and affordability are prized. SA36 steel can perform all those roles and, additionally, is approved for use in boilers, pressure vessels, and other high‑pressure environments that demand the extra certification.
