Astm 307 ~repack~ May 2026

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.

| 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. | astm 307

Grade A is fully threaded and more ductile; Grade B is often partially threaded and has tighter hardness restrictions. 3. Mechanical Properties (Grade A & B) | Property | Grade A | Grade B | |----------|---------|---------| | Tensile Strength | 60,000 psi (min) | 60,000–100,000 psi | | Yield Strength (approx.) | 36,000 psi (min) | No explicit requirement, but typically 36,000–55,000 psi | | Hardness (Rockwell) | B69–B100 | B69–B95 | | Elongation | 18% min (in 8 in.) | 18% min (in 8 in.) | Note: Grade B must pass a hardness test , while Grade A is usually accepted based on tensile and bend tests. 4. Chemical Composition (max values) | Element | Grade A & B | |---------|-------------| | Carbon (C) | 0.29% | | Manganese (Mn) | 1.20% | | Phosphorus (P) | 0.04% | | Sulfur (S) | 0.05% | | Grade | Description | Typical Use |

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 B | Low carbon steel (may be heat treated)