ステンレス鋼の溶接熱サイクル途上における高温延性に関する研究(第2報)

Abstract

Following the first report, six different heats of stainless steels, wrought round bars and wrought plates of type 347, 304 and 304L alloys, were subjected to RPI hot ductility test, and following results were obtained :(1) Among the all test steels, both heats of type 347 showed the lowest value of hot ductility during the cooling portion, while type 304 medium and type 304L the highest.(2) The hot ductility of type 347 alloys showed a considerable scatter, and the wrought plate gave much better ductility than the wrought round bar, which may be contributed to the difference in heat and forming procedure. On the contrary, the difference and scatter of hot ductility of type 304 or 304L were only appreciable.(3) Microsscopic observation indicated that this phenomenon was closely related with the embrittlement due to grain boundary liquation, and the degree of embrittlement of type 347 was the greatest of all.(4) Microscopic obsrvation also showed that the fractures of all grades tested were of intergranular type except of the wrought round bar of type 304L when heated above 900°C.