S355NL vs Q355D
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.
S355NL
Structural & HSLA Steel
S355NL is the low-temperature grade of EN 10025-3 normalized fine-grain structural steels. It matches S355N in strength (yield ≥355 MPa, tensile 470–630 MPa) but guarantees Charpy toughness at −50 °C instead of −20 °C, with tighter P and S limits — the standard European choice for cold-climate and offshore structures.
Standards: DIN 1.0546 (EN 10025-3) · AISI A572 Gr.50 (near) · GB Q355E (near)
Q355D
Structural & HSLA Steel
Q355D is the low-temperature quality of China’s Q355 HSLA series to GB/T 1591 — the successor designation to Q345D. It guarantees impact toughness at −20 °C with tightened P/S limits, and is the standard Chinese plate for bridges and structures that see real winters.
Standards: DIN S355J2 (near) · AISI A572 Gr.50 (near) · JIS SM520C (near) · GB Q355D (GB/T 1591)
Chemical composition compared (%)
| Element | S355NL | Q355D |
|---|---|---|
| C | ≤0.18 | ≤0.18 |
| Si | ≤0.50 | ≤0.50 |
| Mn | 0.90–1.65 | ≤1.60 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.020 | ≤0.020 |
| Nb | ≤0.05 | — |
| V | ≤0.12 | — |
| Al | ≥0.02 | — |
| Cr | ≤0.30 | — |
| Ni | ≤0.50 | — |
| Cu | ≤0.55 | — |
| CEV | ≤0.43 | — |
Properties compared
| Property | S355NL | Q355D |
|---|---|---|
| Yield strength | ≥355 MPa (≤16 mm) | ≥355 MPa (≤16 mm) |
| Tensile strength | 470–630 MPa | 470–630 MPa |
| Elongation | ≥22% | — |
| Impact toughness | 27 J at −50 °C | — |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Impact | — | −20 °C, ≥34 J |
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: S355NL · Q355D. Substitution decisions for certified parts stay with the design authority.