Grade B

ASTM A307 Grade B Specification for medium strength carbon steel bolts, studs, threaded rods & similar externally fasteners with tensile strength between 60 to 100 ksi. ASTM A307 Grade B is a standard material specification for medium strength carbon steel fasteners specially bolts, studs and threaded rods for general purpose applications. Grade B is a heat treated carbon steel bolting material with minimum tensile requirement between 60 to 100 ksi and hardness range from 121 to 212 BHN. ASTM A307 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B Bolts.

Chemical Composition

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

Mechanical Properties

Bolt Grade	Diameter, Inch	Tensile Strength, ksi	Yield Strength ksi	Elongation, %	Hardness, BHN
A	1/4 to 4, inclusive	60	...	18	121 - 241

Recommended Nuts & Washers

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