1.1 This specification covers high-strength low-alloy structural steel plate intended for use in welded construction of naval ships where a savings in weight [mass] is important. Plates that conform to this specification offer improved weldability, formability, and toughness resulting from the specified alloying elements with limitations on carbon, sulfur, and residual element contents. Grades 50 and 65 may be provided as-rolled, control-rolled, thermo-mechanical control processed (including accelerated cooling), normalized, or quenched and tempered as required to meet the specified mechanical requirements. 1.2 The maximum thickness or weight [mass] of plates shall be as follows: Grade Plate thickness, max, in. [mm] Plate weight [mass], max, lb/ft2[kg/m2] 50 2 [50] 81.7 [393] 65 21⁄2 [65] 102 [502] 1.3 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. 1.4 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.