SS400 vs ASTM A36
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.
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)
ASTM A36
Structural & HSLA Steel
ASTM A36 is the most widely used structural carbon steel in North America, the default material for buildings, bridges and general fabrication. Its chemistry limits relax as thickness grows, which is why A36 is a specification of minimum properties rather than a tight analysis.
Standards: DIN S235JR (near) · AISI A36 · JIS SS400 (near) · GB Q235B (near)
Chemical composition compared (%)
| Element | SS400 | ASTM A36 |
|---|---|---|
| P | ≤0.050 | ≤0.040 |
| S | ≤0.050 | ≤0.050 |
| C / Si / Mn | Not specified by JIS G3101 — the grade is defined by its tensile properties, not by chemistry | — |
| C | — | ≤0.25 (plate ≤20 mm) |
| Si | — | ≤0.40 |
| Mn | — | 0.80–1.20 (plate >20 mm) |
Properties compared
| Property | SS400 | ASTM A36 |
|---|---|---|
| Tensile strength | 400–510 MPa | 400–550 MPa |
| Yield strength | ≥245 MPa (≤16 mm) | ≥250 MPa |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Weldability | Excellent in practice (chemistry uncontrolled beyond P/S) | — |
| Elongation | — | ≥20% (200 mm) |
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: SS400 · ASTM A36. Substitution decisions for certified parts stay with the design authority.