The ASTM A307 specification covers carbon steel bolts and studs ranging from 1/4″ through 4″ diameter. This is your everyday, run of the mill bolt specification often manufactured using A36 round bar. There are three grades A, B, and C* which denote tensile strength, configuration, and application. Refer to the Mechanical Properties Chart for the subtle strength differences within each grade.

A307 Grades

A ASTM A307 Grade A Headed bolts, threaded rods and bent bolts intended for general applications.
B ASTM A307 Grade B Heavy hex bolts and studs intended for flanged joints in piping systems with cast iron flanges.
C* ASTM A307 Grade C Nonheaded anchor bolts, either bent or straight, intended for structural anchorage purposes. The end of a grade C anchor bolt intended to project from the concrete will be painted green for identification purposes. Permanent marking is a supplemental requirement. *As of August 2007, grade C has been replaced by specification F1554 grade 36. We will continue to supply grade C, if required by the project.

A307 Mechanical Properties

Grade Tensile, ksi Yield, min, ksi Elong %, 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%

A307 Recommended Hardware

Nuts Washers
A307 Grades A & C* A307 Grade B
1/4 - 1-1/2 1-5/8 - 4 1/4 - 4
A563A Hex A563A Heavy Hex A563A Heavy Hex Unspecified