Abstract
The grain boundary migration in the surface of the weld of an austenitic stainless steel was observed. In the cross section shape of the grain boundary groove, the thermal grooving theory in the surface based on the surface flow was compared to the experimental results. Furthermore, the relationship between the angle which is the plane of the solidification grain boundary to the surface plane and the amount of the grain boundary migration were discussed. The obtained results are as follows.
The relationship between the cross section shape of the grain boundary groove which migrated in the surface of the weld metal and the direction of the grain boundary migration is good agreement with those of thermal grooving theory. That is, the plane of the grain boundary migrates to approach to be a right angle to the surface plane.
The amount of the grain boundary migration increases with increase of the angle of the solidification grain boundary to a right angle of the surface. This reason is why the plane of the grain boundary which has higher angle to a right angle of the surface is able to migrate with less friction force than that which has lower.
