Bondability of Dissimilar Metal Sheets by Shot Peening

In shot peening, bombarding the surface with steel shot propelled at high velocity causes plastic deformation of surface. The process with the characteristic deformation was applied to joining process. Our approach has been applied to the butt joining of the dissimilar metal sheets. In this method, however, the joint strength was lower than the flow stress of base metal. The modified joining processing was being carried out to improve the bondability. In the present study, the joining of dissimilar metal sheets using a shot peening process was investigated to improve the bondability. In the joined section, the edge of the joint area of the sheets were slit using a laser. In this method, the edges of the sheet are overlapped the other sheet. When the connection is peened, the material undergoes large plastic deformation near the surface due to the collision of shots. In this process, particularly noteworthy is the plastic flow near surface layer. The edges of the sheet are joined to the other sheet, thus two sheets can be joined each other. In the experiment, the shot peening treatment was performed by using an air-type peening machine. The shots used were made of high carbon cast steel. Air pressure was 0.6 MPa and peening time was in the range of 30-240s. The metal sheets were commercial low-carbon steel, stainless steel, pure aluminium, aluminium alloy, and pure copper. The effects of processing conditions on the bondability were mainly examined. It was found that the present method was effective for joining of dissimilar metal sheets.