1.1 This specification covers the chemical and mechanical requirements of three grades of carbon steel bolts and studs in sizes 1/4 in. (6.35 mm) through 4 in. (104 mm). 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 (414 MPa) and intended for general applications,
Grade B	Bolts and studs having a tensile strength of 60 to 100 ksi (414 to 690 MPa) and intended for flanged joints in piping systems with cast iron flanges, and
Grade C	Nonheaded anchor bolts, either bent or straight, having properties conforming to Specification A 36 (tensile strength of 58 to 80 ksi (400 to 550 MPa)) and intended for structural anchorage purposes.

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 A 563. Unless otherwise specified, the grade and style of nut for each grade of fastener, of all surface finishes, shall be as follows: Nuts of other grades and styles having specified proof load stresses (Specification A 563, Table 3) greater than the specified grade and style of nut are also suitable.

Fastener Grade and Size	Nut Grade and Style
A, C, 1/4 to 1 1/2 in.	A, hex
A, C, over 1 1/2 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 the standard. The values given in parentheses are for information only.

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.