This specification covers the chemical, mechanical, and metallurgical requirements for two types of heavy hex structural bolts made of quenched and tempered alloy steel and having specified tensile strengths and sizes. These bolts are intended for use in structural connections, and are furnished in nominal bolt diameters M12 through M36. They are designated by type denoting chemical composition as follows: Type 1—medium carbon alloy steel; and Type 3—weathering steel. The bolts shall conform to chemical requirements as examined by heat and product analysis. The bolts shall also be tested, and shall conform accordingly to specified requirements for mechanical properties such as Brinell hardness, Rockwell hardness, microhardness, tensile strength, yield strength, elongation, reduction of area, stress area, tensile load, and proof load; metallurgical properties such as carburization and decarburization; and dimensional properties such that for the head and body, and threads. The bolts shall undergo magnetic particle inspection as well for longitudinal discontinuities and transverse cracks.

1.1 This specification covers two types of quenched and tempered alloy steel, metric heavy hex structural bolts having a tensile strength of 1040 to 1210 MPa.

1.2 These bolts are intended for use in structural connections comparable to those covered under the requirements of the Specification for Structural Joints Using ASTM A 325 and A 490 bolts, approved by the Research Council on Structural Connections; endorsed by the American Institute of Steel Construction and by the Industrial Fastener Institute.

1.3 The bolts are furnished in nominal bolt diameters M12 to M36, inclusive. They are designated by type denoting chemical composition as follows:

1.4 This specification is applicable to metric heavy hex structural bolts and alternate designs as established by the Research Council in its publication, Specification for Structural Joints Using ASTM A 325 and A 490 bolts.

1.5 For inch-pound bolts, see Specification A 490.

1.6 The following safety hazards caveat pertains only to the Test Methods portion, Section 13, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.