Stainless steel grade equivalents

An equivalence table pairs a grade written in one standard with its nearest counterpart in another: an AISI or ASTM type number against an EN or DIN steel number, a UNS number or a JIS SUS designation.

Nearest is the operative word. The bodies behind those standards set their own composition windows, so equivalent grades are close, not identical. AISI 304 allows chromium 18.0 to 20.0 percent, silicon to 0.75 percent and carbon to 0.08 percent; EN 1.4301, its usual equivalent, allows chromium 17.0 to 19.5 percent, silicon to 1.0 percent and carbon to 0.07 percent. The two overlap but they are not interchangeable on paper. Mechanical property requirements, test regimes and product standards differ as well.

So use the tables to read across a drawing or an enquiry, then order against one named standard and check the actual limits before substituting. Every grade below links to its composition in the grades reference, which covers 500+ grades in full.

Read the basis column. 215 of the 297 mappings on this page were checked against the governing standard on 2026-08-18 and are marked verified; the rest were inherited from the previous website, have not been checked, and are marked as such. Two inherited mappings were found to be wrong and have been withdrawn, and they are listed at the foot of the page.

Austenitic grades

46 austenitic grades with a cross-standard equivalent on record. The full family, with composition, is on the austenitic family page.

AISI 302. 1.4310 is sometimes published as an equivalent for AISI 302; this reference assigns it to AISI 301, whose composition window it matches. The mapping is worth checking against the standard itself before substituting.

AISI 305. Corrected 2026-08-18. The value published before that date, 1.4312, is the cast grade G-X10CrNi18-8 and is not AISI 305.

AISI 309. The dataset gives AISI 309 as Cr 22.0-24.0 and 1.4828 as Cr 19.0-21.0: the two windows do not overlap. 1.4828 (X15CrNiSi20-12) is a heat-resisting grade often quoted alongside 309, not a composition match.

AISI 310. The EN number carried here, 1.4845, is the one producers assign to AISI 310 S. It is inherited from the previous website and has not been checked; this dataset gives AISI 310 and AISI 310 S identical composition windows, so the practical difference is small, but a drawing calling for 310 should be ordered against a named standard.

AISI 310 S. Corrected 2026-08-18 from the inherited 1.4842 to 1.4845, the EN number in production use for TYPE 310S.

Duplex grades

10 duplex grades with a cross-standard equivalent on record. The full family, with composition, is on the duplex family page.

S 32003. S32003 has no assigned EN number.

Precipitation Hardening grades

6 precipitation hardening grades with a cross-standard equivalent on record. The full family, with composition, is on the precipitation hardening family page.

17/4-PH. Commonly listed under its AISI type number, 630.

Martensitic grades

17 martensitic grades with a cross-standard equivalent on record. The full family, with composition, is on the martensitic family page.

AISI 431. A widely reproduced SAE table gives S41623 for 431; that is the UNS number of 416Se and was rejected. 431 is S43100.

Ferritic grades

19 ferritic grades with a cross-standard equivalent on record. The full family, with composition, is on the ferritic family page.

Nickel Alloy grades

14 nickel alloy grades with a cross-standard equivalent on record. The full family, with composition, is on the nickel alloy family page.

Tool Steel grades

3 tool steel grades with a cross-standard equivalent on record. The full family, with composition, is on the tool steel family page.

Carbon Steel grades

2 carbon steel grades with a cross-standard equivalent on record. The full family, with composition, is on the carbon steel family page.

Alloy Steel grades

25 alloy steel grades with a cross-standard equivalent on record. The full family, with composition, is on the alloy steel family page.

SAE 4320. The dataset gives SAE 4320 as Cr 0.4-0.6 and EN 354 as Cr 0.75-1.25: the two windows do not overlap.

Mappings withdrawn on 2026-08-18

AISI 302, EN 1.4319. No producer or standards source maps 1.4319 to AISI 302; the trade sources that carry 1.4319 give it as X5CrNi17-7 / SUS 301. Replaced with 1.4300.

AISI 305, EN 1.4312. 1.4312 is the cast grade G-X10CrNi18-8. AISI 305 is 1.4303, verified 2026-08-18.

Composition, family and the rest of the reference sit on the grades page. The computed pitting resistance of every austenitic and duplex grade is on the pitting resistance reference. For what is actually supplied in a given profile, each product page lists the grades rolled or drawn for it.