ASTM A307 Specifications

Technical Menu Posted on July 1st, 2015 by vapro

This specification covers the chemical and mechanical requirements of three grades of carbon steel bolts and studs in sizes 1⁄4 in. through 4 in. ASTM A307 is the most common of all bolt specifications and is often manufactured using A36 round bar. The fasteners are designated by “Grade” denoting tensile strength and intended use, as follows:

Grade A: Bolts and studs having a minimum tensile strength of 60 ksi and intended for general applications

Grade B: Bolts and studs having a tensile strength of 60 to 100 ksi and intended for flanged joints in piping systems with cast iron flanges

Grade C: Replaced by Specification F1554 Gr.36

  • The term studs includes stud stock, sometimes referred to as threaded rod.
  • This specification does not cover requirements for machine screws, thread cutting/forming screws, mechanical expansion anchors or similar externally threaded fasteners.
  • A307 Grade B headed bolts have a heavy hex pattern head.
  • Suitable nuts are covered in Specification A563

Chemical Requirements

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%

Mechanical Requirements

Grade Tensile, ksi Yield, min, ksi Elong %, min
A 60 min 18
B 60 – 100 18
C* 58 – 80 36 23

Related: ASTM A307 Specifications at

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