Patent ID: 8763882
Filing Date: 2014-07-01
Classification: B23K,B32B,C22C,Y10T

Abstract:
1. A friction stir welding method for a metal material for longitudinally welding members to be butted and then welded with at end portions, the method comprising: preparing members to be welded and formed with excess thickness portions and a welding tool provided with a probe for welding the members to be welded while rotating the welding tool in a manner of abutting against the members to be welded, the excess thickness portions being formed so as to protrude on extension surfaces of at least one side weld end portions of butt surfaces of the members to be welded; performing a first welding to the members to be welded so as to weld the butt surfaces of the members to be welded along one side and terminating the butt welding by using the welding tool along the one side of the butt surfaces and terminating the first welding at the beginning of the excess thickness portions; inserting the welding tool from the excess thickness portion to cause plastic flow of the metal material subsequent to the butt-welding along the one side to thereby fill a probe hole remaining in the first welding step after removing the welding tool from the members to be welded; and performing a second welding continuously from the filling along another one side leading from the one side mentioned previously in the preparing of the members to be welded.