Stainless steel grades
15 stainless steel grades from 2 designation systems, each with a full data sheet. Sorted by system; the yield and tensile values are the first line of each grade's mechanical table.
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EN (European)
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Equivalents |
|---|---|---|---|---|---|---|
| 1.4301 | 1.4301 | Austenitic Cr-Ni stainless steel | ≤ 0.07 | ≥ 230 | 540–750 | 304, 304L, SUS304 |
| 1.4305 | 1.4305 | Austenitic free-machining stainless steel (sulphur-bearing) | ≤ 0.1 | ≥ 190 | 500–750 | 303, SUS303, Y12Cr18Ni9 |
| 1.4404 | 1.4404 | Austenitic Cr-Ni-Mo stainless steel, low carbon | ≤ 0.03 | ≥ 240 | 530–680 | 316L, 316, SUS316L |
| 1.4462 | 1.4462 | Ferritic-austenitic (duplex) stainless steel | ≤ 0.03 | ≥ 500 | 700–950 | 2205 (S32205), S31803, F51 / F60 |
| 1.4571 | 1.4571 | Austenitic Cr-Ni-Mo stainless steel, titanium-stabilized | ≤ 0.08 | ≥ 240 | 540–690 | 316Ti, 316L, SUS316Ti |
AISI / SAE
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Equivalents |
|---|---|---|---|---|---|---|
| 17-4 PH | S17400 | Martensitic precipitation-hardening stainless steel | ≤ 0.07 | ≈ 760 (typ.) | ≈ 1030 (typ.) | 1.4542, SUS630, 05Cr17Ni4Cu4Nb |
| 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 |
| 410 | S41000 | Martensitic chromium stainless steel, hardenable | ≤ 0.15 | ≥ 275 | ≥ 485 | 1.4006, SUS410, 12Cr13 |
| 430 | S43000 | Ferritic chromium stainless steel | ≤ 0.12 | ≥ 205 | ≥ 450 | 1.4016, SUS430, 10Cr17 |
Four families, four behaviours
Stainless steel is not one material. Austenitic grades (304, 316, 321) contain enough nickel to hold an austenitic structure at room temperature: non-magnetic, extremely formable, weldable, and the default for corrosion service. Ferritic grades (430, 409) carry chromium but little or no nickel: magnetic, cheaper, less formable, less corrosion resistant. Martensitic grades (410, 420) harden by quenching and go into blades and wear parts. Duplex (2205) mixes austenite and ferrite for roughly double the strength of 304 with better chloride resistance.
Nickel content is what drives both price and behaviour, and it is why 430 costs so much less than 304.
Chromium is the mechanism, not a marketing number
Stainless behaviour starts at about 10.5 % chromium, the point at which a self-repairing chromium-oxide passive layer forms. Everything above that is refinement: more chromium extends the range, molybdenum resists chlorides, nickel stabilises the austenitic structure, nitrogen adds strength.
The practical consequence is that stainless is not rust-proof but rust-*resistant*, and the passive layer needs oxygen to repair itself. Crevices, stagnant water and embedded carbon-steel particles from the wrong grinding disc all defeat it — which is why contamination during fabrication causes more stainless failures than grade selection does.
The L and the H, and why they matter
An L suffix means low carbon, at most 0.03 %. It exists for welding: at normal carbon levels, chromium carbides form at the grain boundaries in the heat-affected zone and strip those boundaries of the chromium that was protecting them. Above about 6 mm welded thickness, specify L.
An H suffix means the opposite — carbon deliberately held high for creep strength at elevated temperature. 304H is a pressure-vessel grade, not a better 304.
faq.h
What is the difference between 304 and 316?
316 contains 2 to 3 % molybdenum and 304 does not. Molybdenum resists chlorides — seawater, salt spray, pool chemistry, de-icing salt. Inland and away from chlorides the two perform alike, and 304 costs 25 to 45 % less.
Is stainless steel magnetic?
Austenitic grades such as 304 and 316 are essentially non-magnetic when annealed, though cold work makes them slightly magnetic. Ferritic 430 and martensitic 410 are magnetic by nature, so a magnet tells you the family, not the quality.
What does the L mean in 316L?
Carbon held at or below 0.03 %. It prevents chromium carbide precipitation in the heat-affected zone during welding, which would otherwise leave the weld vulnerable to intergranular corrosion. Specify L for welded sections above about 6 mm.
How much chromium makes steel stainless?
About 10.5 %, the threshold at which a continuous self-repairing chromium-oxide passive layer forms. Below that the film is not continuous and the steel rusts normally.
Why does my stainless steel show rust spots?
Almost always contamination rather than the grade: carbon-steel particles embedded during grinding or handling, which rust and stain the surface. Use dedicated stainless tooling and passivate after fabrication.