Research on press joining technology for automotive metallic sheets

摘要

Press joining (PJ)is anew kind of technology for sheet joining, which is different from conventional metallic sheets joining technology. It is the process of joining metallic sheets using a die and a punch. This kind of technology has developed rapidly over the past 10 years and it has been applied gradually in such fields as automotive production. Compared with the advantages of the conventional process of spot-welding, the prominent advantages of press joining technology (PJT) are that it can be used for joining metallic sheets of the different materials and various thicknesses, and that it can even be used for the process of joining metallic sheet and non-metallic sheet. Especially for coated steel sheets, such as galvanized steel sheets, and aluminum plating steel sheets, PJT is able to complete the function of joining without damaging the surfaces of the coating layers. It has the advantages of tool construction simplicity, being performed easily, high productivity (the joining of various spots can be completed at one time), low cost, an excellent production environment, and so on. Based on the authors' research work on non-coated steel sheets and coated steel sheets of different materials and various thicknesses, this paper deals mainly with the primary points such as the mechanism of PJT, the metal flow conditions, the principle of formulating of the parameters of PJT, the joining strength of the press-joined parts, and the ways and characteristics of different PJT.