Research on quality and reliability of cold-pressing joining between aluminum and stainless sheets

Lightweight forming was one of the main ways to achieve energy conservation and emission reduction in advanced manufacturing. However, the cold-pressing process was easier to realize dissimilar sheets joining and could reduce the weight of both the material and the structure; therefore, this process was widely used. Taking aluminum and stainless sheets joining as an example, this study designed three kinds of joining schemes based on the theory of materials mechanics. It was concluded that the increase of the load pressure made the joining parts of the two sheets fitted quickly, but it decreased the joining thickness through the research of different joining project results. In the joining process, defects such as overlap, warping, protrusions, pitting, and partial cracking led to decreasing surface quality and reliability of the joining part. It was demonstrated by the sheet specimen unidirectional tensile test that the "embedding" and the "interlocking" were the main mechanisms of cold-pressing joining.