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1.1 This specification covers the chemical and mechanical requirements for two types of quenched and tempered steel bolts and studs for general applications where high strength is required.

1.2 The two types of bolts covered in this specification are:

1.2.1 Type 1—Medium-carbon steel bolts and studs furnished in nominal diameters of 1/4 to 3 in., inclusive.

1.2.2 Type 2—Low-carbon martensite or medium-carbon martensite steel bolts and studs furnished in nominal diameters of 1/4to 1 in., inclusive.

1.3 The bolts and studs shall be Type 1, Type 2, or Type 1 or 2 at manufacturer's option, as specified by the purchaser. When a type is not specified, Type 1 shall be furnished. When elevated temperature applications are involved, Type 1 shall be specified by the purchaser on the order.

1.4 Suitable nuts are covered in Specification A 563. Unless otherwise specified, the grade and style of nut 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 suitable.

Fastener Size and Surface Finish	Nut Grade and Style
1/4 to 11/2 in., plain (or with a coating of insufficient thickness to require over-tapped nuts)	B, hex
Over 11/2 to 3 in., plain (or with a coating of insuffi-cient thickness to require over-tapped nuts)	A, heavy hex
1/4 to 3 in., zinc-coated (or with a coating thicknessrequiring over-tapped nuts)	DH, heavy hex

1.5 Unless otherwise specified, washers ordered with bolts shall be furnished to the requirements of Specification F 436.

1.6 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.

1.7 Terms used in this specification are defined in Terminology F 1789 unless otherwise defined herein.