Abstract
In this paper, we investigated the effect of welding speed and external restraint on the grain growth behavior in the heat-affected zone of austenitic stainless steel, and related it to the growth behavior of the crystals in the weld metal which epitaxially grows from the bond. The following results were obtained in this study.
The restraint during welding makes the heat-affected zone hardened due to the plastic thermal strain originated during heating, and results in the considerable grain-coarsening in the heat-affected zone after being heated over 1400 K-1500 K. Even thougth the grains in the heat-affected zone are coarsened by the restraint, there is almost no difference between the columnar width of the weld metal and that in the case of non-restraint welding. The bond region where there is no epitaxial relation between the weld metal and the heat-affected zone often appears when the grain-coarsening occurs in the heat-affected zone subject to large plastic strain during welding.
