This specification covers high-yield, quenched, and tempered alloy steel plates for use in welded bridges and other structures. Plates shall be subjected to heat treatment to conform to the tensile and hardness requirements for thickness, tensile strength, yield strength, elongation, reduction of area, and Brinell hardness. Heat and product analysis shall conform to the chemical requirements for carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, vanadium, titanium, zirconium, copper, boron, and columbium. Conformance to required mechanical properties shall be determined by tension and hardness tests.

1.1 This specification covers quenched and tempered alloy steel plates of structural quality in thicknesses of 6 in. [150 mm] and under intended primarily for use in welded bridges and other structures.

1.2 If the steel is to be welded, it is presupposed that a welding procedure suitable for the grade of steel and intended use or service will be utilized. See Appendix X 3 of Specification A6/A6M for information on weldability.

1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system is to be used independently of the other, without combining values in any way.