ASTM A240/A240M — Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
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Scope
Flat-rolled stainless steel (plate, sheet, strip) of ferritic, martensitic, austenitic, duplex and PH grades identified by UNS number: 304/304L/304H, 316/316L/316Ti, 321, 347, 309S, 310S, 410, 430, 2205 (S31803/S32205), 2507, 904L, 254 SMO and about 100 others. Gives chemistry, mechanical property minimums, hardness limits, heat-treatment conditions and finishes (via A480). Adopted by ASME as SA-240.
Grades covered by ASTM A240
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| 2205 | S32205 | Ferritic-austenitic (duplex) stainless steel | ≤ 0.03 | ≥ 450 | ≥ 655 | 1.4462, SUS329J3L, 022Cr23Ni5Mo3N |
| 304 | S30400 | Austenitic chromium-nickel stainless steel | ≤ 0.08 | ≥ 205 | ≥ 515 | 1.4301, SUS304, 06Cr19Ni10 |
| 304L | 1.4307 | Low-carbon austenitic chromium-nickel stainless steel | ≤ 0.03 | ≥ 170 | ≥ 485 | 1-4301, 304, 316l |
| 310 | S31000 | Austenitic heat-resisting stainless steel (25 % Cr, 20 % Ni) | ≤ 0.25 | ≥ 205 | ≥ 515 | 1.4845, 1.4841, SUS310S |
| 316 | S31600 | Austenitic chromium-nickel-molybdenum stainless steel | ≤ 0.08 | ≥ 205 | ≥ 515 | 1.4401, 1.4404, 1.4436 / 1.4432 |
| 316L | 1.4404 | Low-carbon austenitic chromium-nickel-molybdenum stainless steel | ≤ 0.03 | ≥ 170 | ≥ 485 | 316, 1-4404, 304 |
| 321 | S32100 | Austenitic Cr-Ni stainless steel, titanium-stabilized | ≤ 0.08 | ≥ 205 | ≥ 515 | 1.4541, SUS321, 06Cr18Ni11Ti |
| 430 | S43000 | Ferritic chromium stainless steel | ≤ 0.12 | ≥ 205 | ≥ 450 | 1.4016, SUS430, 10Cr17 |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1940 | A240 first issued for pressure-vessel plate |
| 2000s | A167 and A176 grades progressively merged into A240 |
| 2022 | A240/A240M-22 — current edition |
Supersedes: ASTM A167 (withdrawn 2014; general-purpose Cr-Ni sheet); ASTM A176 (ferritic/martensitic sheet, merged).
Where to buy the standard
The full text is copyrighted by ASTM International and is not reproduced here. Purchase the current edition from ASTM International or your national standards body. The values on this site are the normative limits as published; the standard's own tables, notes and test methods govern.
Related standards
A240 is a specification, not a grade
This is the single most useful thing to know about the American system. 304 is not a standard; A240 is. ASTM A240 is the specification for chromium, chromium-nickel and chromium-manganese-nickel stainless plate, sheet and strip for pressure vessels and general applications, and it lists dozens of grades by UNS number, of which S30400 — the alloy everyone calls 304 — is one.
The consequence is practical. "304 stainless" names a composition and nothing else: no product form, no condition, no test regime. "ASTM A240 Type 304" names plate or sheet with the solution-annealed condition, the mechanical minimums, the intergranular corrosion test where required and the certificate that goes with them. Ordering the first when the design needed the second is how material arrives that meets its analysis and fails its duty.
A240 never travels alone
Two other documents are always in play. ASTM A480 carries the general requirements — dimensional tolerance, flatness, edge condition, surface finish designations and permitted repairs — for all flat-rolled stainless, and A240 refers to it rather than repeating it. A purchase order that names A240 without A480 has left the tolerance open.
ASTM A262 is the intergranular corrosion practice invoked when sensitisation matters, typically on welded heavy section in the standard-carbon grades. It is not automatic: it is a supplementary requirement that must be on the order. The same applies to positive material identification and to any additional mechanical testing.
How A240 lines up with EN 10088-2
The two standards cover the same materials by different routes. EN 10088-2 identifies by material number — 1.4301, 1.4401, 1.4404 — and states the delivery condition as a suffix (+AT for solution annealed). A240 identifies by UNS number with the type name alongside, and takes the annealed condition as the default.
On composition they are close enough that dual certification is normal: 1.4301 caps carbon at 0.07 % where S30400 allows 0.08 %, so EN material always satisfies the American limit while the reverse needs checking. The mechanical minimums differ slightly — A240 states 205 MPa yield and 515 MPa tensile for 304, EN states 210–230 MPa yield depending on product form — and the surface finish systems do not map at all: 2B, 2R and No. 4 are defined separately in each document.
A240 = product specification; 304 / S30400 = the alloy inside it.
A480 supplies tolerance and finish; order both together.
A262 intergranular testing is a supplementary requirement, not a default.
Dual EN / ASTM certification is routine on coil and plate.
faq.h
Is ASTM A240 the same as 304 stainless?
No. A240 is the specification for stainless plate, sheet and strip; 304 (UNS S30400) is one of the many grades it covers. A complete order names both — the specification for the product and test regime, the grade for the alloy.
What is the difference between A240 and A480?
A240 gives the grades, chemistry, mechanical properties and required testing. A480 gives the general requirements that apply to all flat-rolled stainless: dimensional tolerance, flatness, edge, surface finish and permitted repair. They are used together.
Does A240 cover bar and tube?
No — it is flat products only. Stainless bar is A276 and A479, welded tube A312 and A249, seamless tube A213. Each has its own tolerance and test regime, which is why a grade name alone never identifies a product.
What is the A240 equivalent of 1.4404?
UNS S31603, sold as 316L. Carbon is capped at 0.03 % in both, so they are treated as the same material and dual-certified in practice; the mechanical minimums differ by a few MPa and the surface finish systems are defined separately.
Does A240 require intergranular corrosion testing?
Not by default. ASTM A262 practice is invoked as a supplementary requirement when the application demands it — typically welded heavy section in standard-carbon grades. It has to be on the purchase order before the material is produced.