(SWPS) FOR GAS TUNGSTEN ARC WELDING(CONSUMABLE INSERT ROOT) OF CHROMIUM-MOLYBDENUM STEEL (M-5A/P-5A), 1/8 THROUGH 1/2 IN. THICK, AS-WELDED CONDITION, 1/8 THROUGH 3/4 IN. THICK, PWHT CONDITION, IN521 (HISTORICAL)