The grain boundary migration in the weld metal of an austenitic stainless steel SUS310S was observed. Based on the observation, the effects of the orientation relationship between grain boundaries and the segregation at the solidification boundary on the morphology of room temperature grain boundary were investigated with the correlation of the amount of grain boundary migration. The effect of strain generated during cooling stage in the weld metal on the grain boundary migration was examined using the base metal added the strain which was presumed by FEM. The following results were obtained in this study.The amount of grain boundary migration occurred in a weld metal is small in the case where the grain boundary energy is low or phosphorous in the solidification grain boundary is high. Except for these cases, the amount of grain boundary migration tendsto be large when the solidification grain boundary shape is rough or the distance between the triple junctions of a grain boundary is short.In the base metal added strain during cooling stage, the serrated grain boundary was observed both in the specimen heated under synthetic thermal cycle and in the weld metal. However, it seems to be a minor factor to the grain boundary migration.
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