A36, A240, A516 … and ASME SA equivalents. Issued by ASTM International. 5 grades and 4 standards are documented so far; each grade links to a full data sheet and a graded cross-reference to the other systems.
This is the difference that catches European buyers. A36 is not a grade — it is a specification that a plate must satisfy. Two mills can meet A36 with visibly different chemistry, because the specification sets a yield floor and a tensile range and leaves much of the analysis open.
The practical consequence is that A36 has no Charpy impact requirement in its base form, no upper carbon limit for thin sections, and no single European equivalent. Calling it "the same as S235" is a useful shorthand and a poor basis for a code-governed structure.
The A-number is a filing system
There is no logic in the number that tells you what the standard covers: A36 is structural plate, A53 is pipe, A105 is forgings, A240 is stainless plate, A516 is pressure-vessel plate, A572 is high-strength low-alloy. The digits are chronological, not descriptive.
Where a specification covers several strength levels it names them as grades inside the specification: A516 Grade 60, 65 and 70 are three different steels in one standard, and the number is the tensile strength in ksi. A572 Grade 50 is the yield in ksi. The unit changes between specifications, which is a common source of error.
ASME SA versus ASTM A
For pressure work the same specification appears twice: ASTM A516 and ASME SA-516. The technical content is normally identical; SA is the version adopted into the ASME Boiler and Pressure Vessel Code.
If the vessel is built to ASME, the certificate should say SA. Material certified only to the ASTM version may be acceptable by agreement, but the code authority decides — not the supplier.
faq.h
What is ASTM A36 steel?
A specification for carbon structural steel with a minimum yield of 36 ksi (250 MPa) and a tensile range of 58 to 80 ksi. It is a specification rather than a grade: it sets limits a plate must satisfy, leaving much of the chemistry to the mill.
Is ASTM A36 equivalent to S235JR?
Close but not identical. A36 guarantees 250 MPa yield against 235, but carries no Charpy impact requirement while S235JR is tested at +20 °C. For code work, specify the standard the code names.
What does Grade 70 mean in A516 Grade 70?
A minimum tensile strength of 70 ksi, about 485 MPa. Note that A572 Grade 50 uses the same style for yield strength instead — the unit convention changes between specifications.
What is the difference between ASTM A and ASME SA?
SA is the ASME Boiler and Pressure Vessel Code adoption of the ASTM specification, normally with identical technical content. A vessel built to ASME should have material certified to the SA version.
Does ASTM use UNS numbers?
Yes, for alloy and stainless grades. UNS S30400 is 304 stainless and S31600 is 316. The UNS number identifies the chemistry unambiguously, much as a Werkstoff number does in the EN system.