A stainless steel order can be written against ASTM A240 or EN 10088 — and a buyer who can read both can specify one and accept the other, instead of rejecting a perfectly good heat because the name on the certificate does not match the name on the drawing. The two systems describe the same alloys with different grade names, different limit formats and different certificate conventions.
Here is how they line up, and where they do not.
Two standards, two numbering systems
ASTM A240 is the American standard for chromium and chromium-nickel stainless plate, sheet and strip for pressure vessels and general use. Grades are named by a three-digit number — 304, 316, 2205 — with an optional letter for the carbon variant (304L, 316L).
EN 10088-2 is the European standard for the same product forms. Grades are named 1.4301, 1.4404, 1.4462 — a five-digit material number where the first digit (1) means steel, the next two identify the family, and the last two are the sequential grade number.
| Common name | ASTM A240 | EN 10088-2 |
|---|---|---|
| 304 | 304 (S30400) | 1.4301 |
| 304L | 304L (S30403) | 1.4307 |
| 316 | 316 (S31600) | 1.4401 |
| 316L | 316L (S31603) | 1.4404 |
| 2205 | 2205 (S32205) | 1.4462 |
Where the limits differ
The composition ranges are close but not always identical, because each system tightens or relaxes a limit for its own market. The difference is usually in the carbon or nickel band, and it rarely changes which grade a heat belongs to — but it can change whether a heat written to one standard also satisfies the other. A heat that clears the ASTM 304 carbon limit may sit just outside the EN 1.4301 band, and the reverse.
This is why the safe practice is specify against one standard and accept a certificate that names both, rather than assuming a heat meeting one automatically meets the other. For a welded part, name the L grade in whichever system you write — 316L or 1.4404 — because the carbon limit is the part that matters for welding.
Mechanical values are typical, not transferable
One source of confusion is that the mechanical minimums are stated differently across the two standards — yield and tensile minimums can differ by a few percent, and the elongation and impact requirements are written to different test conventions. The acceptance values come from the standard you name on the order, not from a data sheet.
Certificate conventions
The certificate system is the same language under two names. EN 10204 2.2 is a mill declaration; EN 10204 3.1 carries the actual results for the heat and is signed by an inspector independent of production. ASTM has its own language for the same idea, but in export practice the EN 10204 levels are the lingua franca, and a 3.1 certificate naming the heat and the analysis is what most buyers actually need.
What gets specified wrong
The most common mistake is writing "stainless steel 304" and expecting it to cover both systems. A European fabricator reads 1.4301; an American one reads 304. The grade is nearly the same, but "nearly" is not a requirement — write the material number or the ASTM grade explicitly, and state the standard, so a substitution is caught rather than assumed.
The second mistake is treating the grade number as the certificate. 316L and 1.4404 are the same alloy, but a drawing that names one and receives a certificate for the other will fail a strict receiving inspection. Name both, or name one standard and accept the equivalent.
Bottom line
ASTM A240 and EN 10088-2 describe the same stainless grades with different names. Specify against one standard, name the L grade for anything welded, and accept a certificate that names the equivalent — the heat is the same metal, but the document has to match the drawing.
For the composition limits of the grades we quote most, see the stainless grade guide. If your drawing names a grade in one system and your supplier quotes the other, send both — we will confirm the equivalence before the order runs.