Takanori Nakazawa1, Shunichi Suzuki2, Yoshihiko Tanaka2,Masayuki Tendo1 and Hajime Komatsu3
1Steel Research Laboratories, Nippon Steel Corporation, Futtsu 293-8511
In order to investigate the effect of carbon content on grain boundary sensitization of type 304L and 316L stainless steels during welding, grain boundary corrosion and carbide precipitation were examined using optical and transmission electron microscopy after thermomechanical cycles which simulated high temperature dynamic strain during welding. Compositional profiles at grain boundary were analyzed with EDS in FE-TEM. The total length of sensitized grain boundary was longer than that of grain boundary carbide in both steels. In type 304L steel grain boundary sensitization and carbide were both observed with carbon contents above 0.016%. In type 316L steel grain boundary sensitization occurred with carbon contents above 0.026%, while carbide precipitation on the grain boundary was observed at the carbon content of above 0.015%. The amount of chromium depletion at grain boundary in type 304L steel was larger than that of type 316L steel. The resistance to grain boundary sensitization of type 316L steel was higher than that of type 304L steel.
(Received June 15, 1999)
austenitic stainless steel, carbon content, grain boundary, sensitization, carbide, chronium depletion, grain size, thermomechanical treatment
Please do not copy without permission.