Unlike higher-strength bolts (e.g., ASTM A325 or A490), A307 bolts are not intended for structural connections subject to heavy dynamic or fatigue loading. Instead, they are ideal for light-duty fastening, flanged joints, cast iron connections, and general maintenance. The specification includes two primary grades, plus a third less common grade:
| Grade | Description | Typical Use | |-------|-------------|--------------| | | Low carbon steel (no heat treat required). Soft, ductile, and easily bendable. | General purpose fasteners, pipe flanges, electrical conduits, anchor bolts. | | Grade B | Low carbon steel (may be heat treated). Slightly higher strength and hardness. | Flanged joints in piping systems (especially cast iron flanges), mild machinery assembly. | | Grade C | (Rarely used/obsolete) | Replaced by F1554 for anchor bolts. |
1. Overview ASTM A307 is a standard specification issued by ASTM International for carbon steel bolts, studs, and threaded rods with a minimum tensile strength of 60,000 psi (415 MPa). It is one of the most common, general-purpose fastener standards used in non-critical, low-stress applications, particularly in construction, plumbing, and machinery assembly.