Aug 2025
ASTM A307
ASTM A307 covers carbon steel bolts and studs in sizes ranging from 1/4' to 4' in diameter. It is one of the most common, general-purpose bolt specifications, often produced from A36 round bar. The standard includes three grades — A, B, and C* — which differ in tensile strength, configuration, and intended application. For detailed strength variations within each grade, refer to the Mechanical Properties Chart.
A307 Mechanical Properties
| Grade |
Tensile (ksi) |
Yield, min (ksi) |
Elongation, min (%) |
| A |
60 min |
— |
18 |
| B |
60 – 100 |
— |
18 |
| C* |
58 – 80 |
36 |
23 |
* Grade C applies to specific headed bolts; check the standard for scope and availability.
A307 Chemical Properties
| Element |
Grade A |
Grade B |
| Carbon, max |
0.29% |
0.29% |
| Manganese, max |
1.20% |
1.20% |
| Phosphorus, max |
0.04% |
0.04% |
| Sulfur, max |
0.15% |
0.05% |