ASTM A 307 : 2021

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

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

1.3Suitable 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:

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

1.5Supplementary 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.

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

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