Process for working metal material and structures

摘要

A process comprising the first step (S01) of conducting friction stir welding of a metal material while feeding an additive to the welding area in order to inhibit the material from grain enlargement in the subsequent melt working and the step (S02) of subjecting the resulting material to melt working such as MIG welding. The additive comprises both a substance which is unreactive to the metal material and has a melting point higher than that of the material and a substance which has a misfit within Ò15% for the material. According to the process, the grain enlargement due to melt working can be inhibited, whereby the weld strength is improved.