Method for improving weldability of dissimilar metal friction stir welding joint

According to the method for improving weldability of the dissimilar metal friction stir welding joint, on the premise that heat treatment of a whole plate is avoided, pre-friction stir machining is conducted on the local part of the joint; through the crushing effect and the friction heat effect generated by high-speed rotation of the stirring needle, local refinement of joint structures of hard metal such as steel and titanium alloy is achieved, structure coarsening and mechanical property reduction of the whole plate are avoided, the fluidity of the joints in the subsequent welding process can be improved, and therefore the overall performance of components is improved. In addition, in the pre-stirring friction machining process, the refining degree of crystal grains is further improved by pre-embedding an additive phase, the fine grain area of a connector is enlarged, and generation of intermetallic compounds in the subsequent welding process is restrained. 本申请提供一种提高异质金属搅拌摩擦焊接头可焊性的方法，其在避免整张板材热处理的前提下，对接头的局部