Pressure-vessel plate
ASTM A387 Grade 91 Cl.2 — chemistry & properties
ASTM A387 Grade 91 Cl.2 (Pressure-vessel plate, UNS K90901): chemical composition and mechanical properties. Grade 91 plate for headers and high-temperature vessels
Chemical composition (wt %)
| C | 0.08 – 0.12 |
| Mn | 0.3 – 0.6 |
| P | ≤ 0.02 |
| S | ≤ 0.01 |
| Si | 0.2 – 0.5 |
| Cr | 8 – 9.5 |
| Ni | ≤ 0.4 |
| Mo | 0.85 – 1.05 |
| N | 0.03 – 0.07 |
Mechanical properties
| Tensile strength, min | 585 MPa |
| Yield strength, min | 415 MPa |
| Elongation, min | 18 % |
| Hardness | Not specified |