SS 316L vs 904L
SS 316L (UNS S31603) vs 904L (UNS N08904): chemical composition and mechanical properties side by side.
- Strength: 904L minimum yield is 220 MPa vs 170 MPa for SS 316L (+29%); tensile 490 vs 485 MPa.
- Density: 7.98 vs 8.0 g/cm³ — 904L is 0.3% heavier.
- Pitting resistance (PREN, min): 22.6 vs 32.2 — higher for 904L.
- Typical use: SS 316L — Most specified process stainless. 904L — Sulphuric acid and chloride service.
| Property | SS 316L | 904L |
|---|---|---|
| Family | Austenitic stainless | Super austenitic |
| UNS | S31603 | N08904 |
| EN / W.Nr | 1.4404 X2CrNiMo17-12-2 | 1.4539 X1NiCrMoCu25-20-5 |
| Basis spec | ASTM A240 | ASTM A240 |
| Density g/cm³ | 7.98 | 8.0 |
| Chemical composition, % | ||
| C | 0.030 | 0.020 |
| Mn | 2.00 | 2.00 |
| P | 0.045 | 0.045 |
| S | 0.030 | 0.035 |
| Si | 0.75 | 1.00 |
| Cr | 16.0–18.0 | 19.0–23.0 |
| Ni | 10.0–14.0 | 23.0–28.0 |
| Mo | 2.00–3.00 | 4.0–5.0 |
| N | 0.10 | 0.10 |
| Cu | – | 1.0–2.0 |
| Mechanical properties (min) | ||
| Tensile strength | 485 MPa (70 ksi) | 490 MPa (71 ksi) |
| Yield strength (0.2%) | 170 MPa (25 ksi) | 220 MPa (32 ksi) |
| Elongation | 40% | 35% |
| Hardness (max) | 217 HB | 90 HRB |
| PREN (min, from spec) | 22.6 | 32.2 |
Single values are maximums; ranges are min–max; "bal" = balance. Limits are typical of the basis specification for that product form — forgings, pipe and fittings specifications differ slightly. Always check the exact specification, edition and the mill test certificate.
Frequently asked questions
What is the difference between SS 316L and 904L?
Strength: 904L minimum yield is 220 MPa vs 170 MPa for SS 316L (+29%); tensile 490 vs 485 MPa. Density: 7.98 vs 8.0 g/cm³ — 904L is 0.3% heavier. Pitting resistance (PREN, min): 22.6 vs 32.2 — higher for 904L.
Which is stronger, SS 316L or 904L?
904L has the higher minimum yield strength (220 MPa vs 170 MPa).
Last updated 2026-11-02