310S vs 309S
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.
310S
Stainless Steel
310S is the low-carbon version of 310 and the most common heat-resistant sheet and plate grade for welded furnace fabrications. It keeps the oxidation resistance of 310 with better weld-zone behaviour.
Standards: DIN 1.4845 · AISI 310S · JIS SUS310S · GB 06Cr25Ni20
309S
Stainless Steel
309S is the low-carbon version of 309, preferred for welded high-temperature fabrications because it resists carbide precipitation in weld zones. Oxidation resistance matches 309.
Standards: DIN 1.4833 · AISI 309S · JIS SUS309S · GB 06Cr23Ni13
Chemical composition compared (%)
| Element | 310S | 309S |
|---|---|---|
| C | ≤0.08 | ≤0.08 |
| Si | ≤1.50 | ≤1.00 |
| Mn | ≤2.00 | ≤2.00 |
| P | ≤0.045 | ≤0.045 |
| S | ≤0.030 | ≤0.030 |
| Cr | 24.00–26.00 | 22.00–24.00 |
| Ni | 19.00–22.00 | 12.00–15.00 |
Properties compared
| Property | 310S | 309S |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness | ≤217 HB (annealed) | ≤217 HB (annealed) |
| Tensile strength | 515–690 MPa | 515–690 MPa |
| Density | 7.90 g/cm³ | 7.90 g/cm³ |
| Max scaling temperature | ~1035 °C continuous | ~980 °C continuous |
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: 310S · 309S. Substitution decisions for certified parts stay with the design authority.