Welding process for friction stir welding

The invention discloses a welding process for friction stir welding. The process comprises the following steps: S1, welding preparation: carrying out surface treatment on two workpieces to be welded, and then butting parts to be welded; and S2, welding: placing the workpieces to be welded in a welding box charged with a protective gas, tightly bonding a stirring head with the workpieces and then rotating the stirring head, generating friction stir heat during the rotation and advance processes, transferring the heat in the two workpieces to realize welding, and rapidly cooling welding seams during the welding process. The welding process for friction stir welding disclosed by the invention has the following benefits: the influence of a high temperature on the quality of the welding seams is adequately considered, and the welding seams are rapidly cooled by virtue of a cooling medium, thus obtaining a better welding quality.