A516 Gr.70 vs Q345R
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.
A516 Gr.70
Structural & HSLA Steel
ASTM A516 Grade 70 is the most specified pressure-vessel plate in the world — the default carbon steel for ASME Section VIII vessels. Its 485–620 MPa tensile band and fine-grain, killed practice give reliable toughness and weldability across a wide thickness range.
Standards: DIN P355GH (near) · AISI A516 Gr.70 · JIS SGV480 (near) · GB Q345R (near)
Q345R
Structural & HSLA Steel
Q345R is China’s standard pressure-vessel plate to GB/T 713 — the R (容， vessel) variant of the Q345 family with tighter sulfur, phosphorus and inspection requirements. It is the default domestic grade for GB 150 coded vessels and the usual Chinese offer against A516 Gr.70.
Standards: DIN P355GH (near) · AISI A516 Gr.70 (near) · GB Q345R (GB/T 713)
Chemical composition compared (%)
| Element | A516 Gr.70 | Q345R |
|---|---|---|
| C | ≤0.27 (≤12.5 mm) | ≤0.20 |
| Si | 0.15–0.40 | 0.15–0.40 |
| Mn | 0.85–1.20 | 1.20–1.60 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.025 | ≤0.015 |
| Al | — | ≥0.020 |
Properties compared
| Property | A516 Gr.70 | Q345R |
|---|---|---|
| Yield strength | ≥260 MPa | ≥345 MPa (≤16 mm) |
| Tensile strength | 485–620 MPa | 510–640 MPa |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
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: A516 Gr.70 · Q345R. Substitution decisions for certified parts stay with the design authority.