ASTM A307 : 21

Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 PSI Tensile Strength

Standard Details

1.1 This specification2 covers the chemical and mechanical requirements of two grades of carbon steel bolts and studs in sizes ¹/₄ in. through 4 in. The fasteners are designated by “Grade” denoting tensile strength and intended use, as follows:

Grade	Description

Grade A	Bolts, studs, and threaded rod having a minimum tensile strength of 60 ksi and intended for general applications,
Grade B	Bolts, studs, and threaded rod^A having a tensile strength of 60 to 100 ksi and intended for flanged joints in piping systems with cast iron flanges, and
Grade C	Replaced by Specification F1554 Gr.36

1.2 This specification does not cover requirements for machine screws, thread cutting/forming screws, mechanical expansion anchors or similar externally threaded fasteners.

1.3 Suitable nuts are covered in Specification A563. Unless otherwise specified, the grade and style of nut for each grade of fastener, of all surface finishes, shall be as follows:

Fastener Grade and Size	Nut Grade and Style^A
A ¹/₄ to 1¹/₂ in.	A, hex
A over 1¹/₂ to 4 in.	A, heavy hex
B, ¹/₄ to 4 in.	A, heavy hex

1.4 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 Supplementary Requirement S1 of an optional nature is provided, which describes additional restrictions to be applied when bolts are to be welded. It shall apply only when specified in the inquiry, order, and contract.

1.6 Terms used in this specification are defined in Terminology F1789 unless otherwise defined herein.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International StandardDetails, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.