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ASTM A307 Specification

ASTM A307 - Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60000 PSI Tensile Strength

This specification covers the chemical and mechanical requirements for three grades (Grades A, B, and C) of carbon steel bolts and studs in specified sizes. However Grade C has been replaced by another specification under ASTM F1554 Grade 36. This specification does not cover the requirements for machine screws, thread cutting/forming screws, mechanical expansion anchors, or other similar externally threaded fasteners. When tested, sampled specimens shall adhere to specified values for chemical composition, hardness, tensile strength, yield point, elongation, and dimensions.

ASTM A307 Grades

Grade Description
Grade A Bolts with a minimum tensile strength of 60 ksi, intended for general purpose applications.
Grade B Bolts with a tensile strength between 60 to 100 ksi and intended for flanged joints in piping systems.

ASTM A307 Properties

ASTM A307 Chemical Composition

Element % Grade A Grade B
Carbon, Max 0.29 0.29
Manganese, Max 1.2 1.20
Phosphorus, Max 0.04 0.04
Sulfur, Max 0.15 0.05

ASTM A307 Mechanical Properties

Grade Tensile, ksi Yield, min, ksi Elongation, min, %
A 60 min -- 18
B 60-100 -- 18

Recommended Nuts & Washers

ASTM A307 Grade A ASTM A307 Grade B Washers
1/4" to 1-1/2" 1-5/8" to 4" 1/4" to 4"
ASTM A563 A Hex ASTM A563A Heavy Hex ASTM A563A Heavy Hex ASTM F844

ASTM A307 Bolt Marking

Grade Symbol
Grade A 307A
Grade B 307B