FRICTION STIR WELDING METHOD FOR PLATINUM OR PLATINUM BASED ALLOY AND FRICTION STIR WELDING STRUCTURE

摘要

PROBLEM TO BE SOLVED: To prevent strength reduction at a welded part by eliminating a foreign matter phase serving as the starting point of flaw when workpieces made of platinum etc. are welded using a friction stir welding method.;SOLUTION: The workpieces are made of platinum or platinum base alloy and the friction stir welding method includes a preheating step prior to a step of generating a plastic range. In the preheating step, the region to be welded is reduced and activated by preheating the region to be welded to not less than the dissociation temperature of adsorbed gas molecules, such as oxygen molecules, nitrogen molecules, or water molecules adsorbed on the surface of the region to be welded and a compound layer, such as oxygen formed on the surface of the region to be welded and under the melting point of the workpieces, and thus the adsorbed gas molecules and the compound layer are removed.;COPYRIGHT: (C)2004,JPO