FILLER MATERIAL FOR LASER BEAM WELDING OF MARTENSITIC STAINLESS STEEL

摘要

PROBLEM TO BE SOLVED: To improve soundness of welding joint by using a high Ni-Cr alloy filler having a specified composition so that weld metal to be formed is made to ferrite/austenite mixed structure when martensitic stainless steel is butt welded with laser beam welding. SOLUTION: A filler material used for welding has a composition consisting of, by weight, =0.10% C, 35-60% Cr eq, =30% Ni eq and the balance Fe with inevitable impurities and in which Cr eq and Ni eq simultaneously satisfy te equation I, II. By using the filler material, a base metal dilution rate is higher as compared with arc welding and structure of weld metal is made to ferrite austenite mixed containing a ferrite phase of =5%, generation of solidification crack and hardening crack is avoided despite rapid cooling laser beam welding. Also, an state to use the filler material is either of a wire, powder and foil.