1.1 This specification covers chromium-tungsten-molybdenum-vanadium, with or without tantalum, alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature service. 1.2 This specification covers standard requirements for chromium-tungsten-molybdenum-vanadium, with or without tantalum, alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature service. The steel shal