Method for improving strength of aluminum lithium alloy welding connector through surface protection

The invention discloses a method for improving the strength of an aluminum lithium alloy welding connector through surface protection. A 1xxx series pure aluminum plate is rolled on the surface of an original aluminum lithium alloy plate to form a wrapping layer, and friction-stir welding is conducted on a composite plate. For an alloy containing aluminum and lithium, compared with a common unprotected welding method, the method for improving the strength of the aluminum lithium alloy welding connector through surface protection can reduce lithium element burning losses, ensure that the performance of the aluminum lithium alloy plate is uniform and effectively improve the strength of the welding connector obtained after welding. Meanwhile, the thickness of a 1xxx series pure aluminum layer can be changed according to requirements of practical conditions so that the 1xxx series pure aluminum layer can adapt to different use environments. In addition, double-face friction-stir welding can be conducted by rollin