1.1 This specification covers the chemical and mechanical requirements of three 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 and studs having a minimum tensile strength of 60 ksi and intended for general applications,
Grade B | Bolts and studs 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

1.1.1 The term studs includes stud stock. sometimes referred to as threaded rod.

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, 1/4 to 1-1/2 in. | A, hex
A, over 1-1/2 to 4 in. | A, heavy hex
B, 1/4 to 4 in. | A, heavy hex

Nuts of other grades and styles having specified proof load stresses (Specification A563, Table 3) greater than the specified grade and style of nut are also suitable.

1.4 The values stated in inch-pound units are to be regarded as the 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.