SS490 vs SS400
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.
SS490
Structural & HSLA Steel
SS490 is the higher-strength grade of JIS G3101, a 490–610 MPa tensile class structural steel with yield of at least 285 MPa in thin sections. Like SS400 it is specified by properties only, with phosphorus and sulfur capped and no carbon control.
Standards: DIN 1.0044 (S275JR, near) · AISI A572 type (near) · JIS SS490 (JIS G3101) · GB Q275 (near)
SS400
Structural & HSLA Steel
SS400 is Japan’s general structural steel under JIS G3101 and one of the most traded structural grades in Asia. The “400” is its minimum tensile class (400–510 MPa); the standard caps only phosphorus and sulfur and leaves carbon and manganese to the mill, so SS400 is bought on mechanical properties, not chemistry.
Standards: DIN 1.0038 (S235JR, near) · AISI A36 (near) · JIS SS400 (JIS G3101) · GB Q235B (near)
Chemical composition compared (%)
| Element | SS490 | SS400 |
|---|---|---|
| P | ≤0.050 | ≤0.050 |
| S | ≤0.050 | ≤0.050 |
| C / Si / Mn | Not specified by JIS G3101 — the grade is defined by its tensile properties, not by chemistry | Not specified by JIS G3101 — the grade is defined by its tensile properties, not by chemistry |
Properties compared
| Property | SS490 | SS400 |
|---|---|---|
| Tensile strength | 490–610 MPa | 400–510 MPa |
| Yield strength | ≥285 MPa (≤16 mm) | ≥245 MPa (≤16 mm) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Weldability | — | Excellent in practice (chemistry uncontrolled beyond P/S) |
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: SS490 · SS400. Substitution decisions for certified parts stay with the design authority.