Research On The Quality And Reliability Of The Cold-Pressing Joining Of The Matched Plate

Lightweight is one of the effective ways to achieve energy conservation and emission reduction in the field of aerospace and automotive, so a large number of new structural materials such as aluminum magnesium alloy and composite materials are emerging and widely used. But it is difficult to realize the connection between these materials and steel or each other, especially for the traditional connection technology, there is a problem that the quality is difficult to guarantee or the technology is difficult to overcome. For example, laser welding is efficient, reliable, and has less heat-affected zone, but the cost is relatively high and is difficult to connect multilayer sheets; spot welding can not realize the connection between heterogeneous sheets. Although riveting joining can realize the connection between heterogeneous sheets, the connecting components obviously increases the weight of the connections. Sheet material, thickness and the number of layers have no influences on the connections in thread joining, but the connections are easy to loose during long time performance. Press circle connection is a widely used technology in heterogeneous sheets joining, but the carrying capacity on the thickness direction is poor and the sheets are easy to fall off.To this end, this paper presents a new method for the cold-pressing connection of the matched plate. The matched cold-pressing connection is one of the mechanical connection method, the ends of each sheet for preliminary joining are preprocessed into the convex tooth and groove, which shapes and sizes are matched. Then put the two sheets after lapped on the worktable of the pressing equipment, and press along the normal direction, the joining is realized by interlock between the deformed convex tooth and groove. To achieve the ideal joining, the convex tooth is processed on the side that has lower yield strength usually, and the convex tooth shape can be different from the matched groove in the same degree, they could be processed to rectangle, trapezoid, zigzag and so on.The matched cold-pressing of AA1100 pure aluminum sheets and 304 stainless steel sheets were taken for experimental studying in this article. It was reached systematically that the effects of process conditions such as the loading pressure, the thickness of the aluminum sheets and the joint structure on joining process and quality. As results shown, there was shunt behavior on the joint area of the aluminum sheet. The thickness of the joining decreased from the center to the both sides sequentially. The thickness of the aluminum sheets was proportional to the joining strength and the loading pressure was inversely proportional to the joining strength when the other parameters were all the same. This study provides the technical reserves for the development of cold-pressing connection deformation of dissimilar sheets.