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 Grades
| A |
 |
Used for general-purpose applications such as headed bolts, bent bolts, and threaded rods where no special strength requirements are specified. |
| B |
|
Typically supplied as heavy hex bolts or studs, designed for use in flanged joints within piping systems, especially with cast iron flanges. |
| C* |
|
Primarily intended for straight or bent anchor bolts used in structural anchoring. Bolts projecting from concrete are often painted green for identification. *Note: Since August 2007, Grade C has been replaced by ASTM F1554 Grade 36. However, Grade C may still be supplied upon request. |
A307 Mechanical Properties
| Grade |
Tensile Strength (ksi) |
Yield Strength, min. (ksi) |
Elongation %, min. |
| A |
60 min |
-- |
18 |
| B |
60 - 100 |
-- |
18 |
| C* |
58 - 80 |
36 |
23 |
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% |