904L vs 317L
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
904L
Stainless Steel
904L is a high-nickel, molybdenum- and copper-bearing super-austenitic stainless developed for sulfuric acid and hot chloride service. Copper gives it resistance to reducing acids that defeat 316L, while 4–5% molybdenum covers pitting.
Standards: DIN 1.4539 · AISI 904L (UNS N08904) · GB 015Cr21Ni26Mo5Cu2
317L
Stainless Steel
317L is the low-carbon version of 317, with 3–4% molybdenum for welded equipment in hot chloride and acid service beyond the capability of 316L. Its PREN of about 30 bridges the gap to super-austenitic grades.
Standards: DIN 1.4438 · AISI 317L · JIS SUS317L · GB 022Cr19Ni13Mo3
Chemical composition compared (%)
| Element | 904L | 317L |
|---|---|---|
| C | ≤0.020 | ≤0.030 |
| Si | ≤1.00 | ≤0.75 |
| Mn | ≤2.00 | ≤2.00 |
| P | ≤0.045 | ≤0.045 |
| S | ≤0.035 | ≤0.030 |
| Cr | 19.00–23.00 | 18.00–20.00 |
| Ni | 23.00–28.00 | 11.00–15.00 |
| Mo | 4.00–5.00 | 3.00–4.00 |
| Cu | 1.00–2.00 | — |
| N | ≤0.10 | ≤0.10 |
Properties compared
| Property | 904L | 317L |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness | ≤217 HB (annealed) | ≤217 HB (annealed) |
| Tensile strength | 490–690 MPa | 515–690 MPa |
| Density | 7.90 g/cm³ | 7.90 g/cm³ |
| PREN | ~35 | — |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: 904L · 317L. Substitution decisions for certified parts stay with the design authority.