This specification covers high-strength low-alloy structural steel plates intended for use in welded construction of naval ships where a savings in weight (mass) is important. The steel shall be made to fine grain practice. The plates shall optionally undergo heat treatment such as quenching or tempering to meet the requirements on mechanical properties such as yield point, yield strength, elongation, and Charpy V-notch impact, provided that the treatment be reported on the test report. The specimen shall undergo heat and product analyses and conform to the chemical composition values of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, copper, vanadium, columbium, aluminum, titanium, and nitrogen.

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.