Stud bolts / bolting
ASTM A320 L7M — chemistry & properties
ASTM A320 L7M (Stud bolts / bolting, UNS G41400): chemical composition and mechanical properties. Low-temperature bolting where hardness control is needed (sour service)
Chemical composition (wt %)
| C | 0.38 – 0.48 |
| Mn | 0.75 – 1 |
| P | ≤ 0.035 |
| S | ≤ 0.04 |
| Si | 0.15 – 0.35 |
| Cr | 0.8 – 1.1 |
| Mo | 0.15 – 0.25 |
Mechanical properties
| Tensile strength, min | 690 MPa |
| Yield strength, min | 550 MPa |
| Elongation, min | 18 % |
| Hardness | 235 HBW (99 HRB) max |
| Impact test | −73 °C (27 J avg) |