The invention relates to a method for connecting an aluminum
alloy and steel by a
laser filler wire, which is suitable for the field of dissimilar material connection and particularly suitable for the connection between dissimilar materials of which fusion points and thermal physical properties differ from each other greatly. The method comprises the following steps of: assembling a
lap joint in which an aluminum plate is arranged on a steel plate, wherein a
laser beam, a wire feeding
nozzle and a protective gas
nozzle are fixed in the same plane, the
laser beam is vertically incident, and a laser focus, a wire dropping point of a
welding wire and a protective gas feeding point are guaranteed to be consistent during
welding; and melting the fed aluminum
welding wire by using the laser to ensure that the molten aluminum welding wire is in fusion connection with the aluminum plate, simultaneously a micro fusion layer is formed on one side of the steel plate and then a fusion-braze welding connection is formed, thus the
lap joint between dissimilar metals such as the aluminum
alloy and the steel is realized. The method improves the connection efficiency between the dissimilar metals such as the aluminum
alloy and the steel, and the tensile strength of the joint is over 149.6N / mm. The method solves the problems of long preparation time, low
automation degree and poor reproducibility of welding results in the process of connecting pre-coated
layers of the dissimilar materials such as welded-aluminum and the steel.