ASTM A307 Specification for carbon steel bolts, studs, threaded rods & similar externally fasteners with min 60 ksi tensile strength.

ASTM A307 specification covers the chemical and mechanical requirements for three grades (Grades A, B, and C) of carbon steel bolts, studs, threaded rods with minimum tensile requirement of 60 ksi. However Grade C has been replaced by ASTM F1554 Grade 36 Specification. A307 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.

Bolt Grades

Type	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.
Grade C	Replaced with ASTM F1554 Grade 36 Specification

Chemical Composition

Element	Grade A	Grade B
Carbon	0.29	0.29
Manganese, max	1.20	1.20
Phosphorus, max	0.04	0.04
Sulfur, max	0.15	0.05

Mechanical Properties

Bolt Grade	Diameter, Inch	Tensile Strength, ksi	Elongation, %	Hardness, BHN
A	1/4 to 4, Inclusive	60	18	121 - 241
B	1/4 to 4, Inclusive	60 - 100	18	121 - 212

Recommended Nuts & Washers

Bolt Specification	Bolting Diameter, Inch	Nut Specification	Washer Specification
A307 Grade A	1/4 to 4, Inclusive	ASTM A563 Grade A	ASTM F844
A307 Grade B