Laser Welding of Stainless Steel Weld Filler Metals at High Cooling Rates.

摘要

Several stainless steels were laser welded under conditions resulting in high cooling rates of the welds. Significant changes in the microstructures, compared to those produced by conventional welding techniques, were found. For alloys 304, 308, 309, 316 and 347, a general decrease in ferrite content with increasing cooling rate was found. For three alloys (304, 308, 347), a fully austenitic structure was obtained at the highest cooling rates. For alloys 312 and 446, the high cooling rates retarded the formation of austenite, resulting in higher ferrite contents and fully ferritic structures at the highest cooling rates. Only for alloy 310 was the microstructure after laser welding comparable to that found after conventional welding. The results are discussed in terms of their impact on the Schaeffler diagram and its applicability to laser welding. 11 refs., 7 figs. (ERA citation 13:048974)