This specification covers the chemical, mechanical, and dimensional requirements for two types of heavy hex structural bolts made of quenched and tempered steel that are intended for use in structural connections. These bolts are designated by type, denoting chemical composition, as follows: Type 1—medium carbon, carbon boron, or medium carbon alloy steel; and Type 3—weathering steel. The steel bolts shall undergo heat and product analysis for chemical composition measurements. The bolts shall also undergo test that shall examine their conformance to specified properties such as dimensions and thread fit, surface discontinuities, coating weight and thickness, hardness, tensile strength, yield strength, elongation, reduction of area, proof load, and rotational capacity.

1.1 This specification covers two types of quenched and tempered steel heavy hex structural bolts having a minimum tensile strength of 120 ksi for sizes 1.0 in. and less and 105 ksi for sizes over 1.0 to 1½ in., inclusive.

1.2 The bolts are intended for use in structural connections. These connections are covered under the requirements of the Specification for Structural Joints Using ASTM A325 or A490 Bolts, approved by the Research Council on Structural Connections, endorsed by the American Institute of Steel Construction and by the Industrial Fastener Institute.