A387 Gr.12 vs A387 Gr.11
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.
A387 Gr.12
Structural & HSLA Steel
ASTM A387 Grade 12 is the 1Cr-0.5Mo vessel plate, one step below Grade 11 in chromium and high-temperature strength. It serves moderately hot pressure equipment where full 1.25Cr alloy is not required.
Standards: DIN 13CrMo4-5 (near) · AISI A387 Gr.12 Cl.2 · JIS SCMV3 (near) · GB 15CrMoR (near)
A387 Gr.11
Structural & HSLA Steel
ASTM A387 Grade 11 is the 1.25Cr-0.5Mo pressure-vessel plate for elevated-temperature service in refineries and petrochemical plant. Class 2 is the higher-strength, tempered condition normally specified for reactors and separators.
Standards: DIN 13CrMo4-5 (near) · AISI A387 Gr.11 Cl.2 · JIS SCMV3 (near) · GB 15CrMoR (near)
Chemical composition compared (%)
| Element | A387 Gr.12 | A387 Gr.11 |
|---|---|---|
| C | 0.05–0.17 | 0.05–0.17 |
| Si | 0.15–0.40 | 0.50–0.80 |
| Mn | 0.40–0.65 | 0.40–0.65 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.025 | ≤0.025 |
| Cr | 0.80–1.15 | 1.00–1.50 |
| Mo | 0.45–0.60 | 0.45–0.65 |
Properties compared
| Property | A387 Gr.12 | A387 Gr.11 |
|---|---|---|
| Yield strength | ≥275 MPa (Class 2) | ≥310 MPa (Class 2) |
| Tensile strength | 485–620 MPa (Class 2) | 515–690 MPa (Class 2) |
| 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: A387 Gr.12 · A387 Gr.11. Substitution decisions for certified parts stay with the design authority.