High strength steel-aluminum alloy dissimilar metal connecting method

The invention relates to a high strength steel-aluminum alloy dissimilar metal connecting method in the technical field of metallurgy, material, machinery and automobile, railway vehicle and other mobile machines. The method, aiming at the welding problem of high strength steel-aluminum alloy dissimilar metal, utilizes an orthogonal design test method to optimize a resistance spot-welding parameter, based on thermal, electric and force coupling characteristics of the steel-aluminum alloy dissimilar metal in a spot-welding process and rule of influence of the spot-welding parameter on the diameter of an aluminum alloy nugget, thickness of an intermetallic compound layer on an aluminum/steel interface, joint pulling and shearing force, spot-welding defects and the like; so that, to a certain extent, the diameter of the aluminum alloy nugget is increased, the growth of intermetallic compound layer on the aluminum/steel interface is limited, splashing in spot-welding and defects of joint breaking, shrinkage cavities, incomplete fusion and the like are prevented, and thus the mechanical property and spot-welding quality of the high strength steel-aluminum alloy dissimilar metal resistance spot-welded joint are improved. The specific technical steps are as follows: treating the surface of weldment, adopting F type electrode and optimized spot-welding parameter, and connecting high strength steel-aluminum alloy by spot-welding.