REPAIR WELDING STUDIES ON CA6 NM MARTENSITIC STAINLESS STEEL CASTING

摘要

Martensitic stainless steel castings are used in hydel power station runner and other components. For repair welding martensitic fillers are used. Repair welds in cast CA6-NM stainless steels made with matching filler metal have been consistently harder than the base metal. High hardness causes machining problem. Severe constraints for in-situ post weld heat treatment of complex shape runners and other operational needs force plant engineers to use " soft austenitic fillers" and operate the runners in the "as welded condition". This paper deals with the study carried out on welding of martensitic stainless steel castings with high nickel austenitic and duplex filler along with the matching martensitic filler.