Laser repair welding process for Zn-Al alloy

The invention relates to a welding process for Zn-Al alloy, in particular to a laser repair welding process for Zn-Al alloy. Zn-Al alloy which needs to be treated by laser repair welding is taken, and a welding lug is placed on a portion, which needs to be treated by laser repair welding, of the Zn-Al alloy; laser welding is performed after parameters of a laser are adjusted; the welding lug is cut from alloy of which the material is the same with that of the Zn-Al alloy; and in a laser welding process, the edge of the welding lug is molten by laser at first, so that the welding lug is fixed on a substrate, a laser spot is aligned to the center of the welding lug to melt the welding lug, and the molten area is spirally diffused to the edge of the welding lug from the center of the welding lug until the welding lug is molten completely. Welded joints are smooth and continuous; the welding lug is molten completely; and the average microhardness of a repair welding area is higher than that of the substrate. The