Mechanical Clinching for Aluminum Alloy Die-Casting and High Strength Steel Sheet

The joinabilities of mechanical clinching of a thick aluminum alloy casting and three thin steel sheets (tensile strengths : 590, 780, and 980 MPa) were experimentally investigated. The effects of the sheet combination and the die shape on the joining range were shown. In addition, the joint load was measured. By mechanical clinching, the upper 4 mm thickness of aluminum alloy casting and the lower 1.2 mm thickness of steel sheet under 780 MPa steel were joined without defects in a suitable die shape, although the interlock was formed with the cracks occurred on the bottom corner of the lower sheet for 980 MPa steel sheet. The upper high-strength steel sheet and the lower aluminum alloy casting were joined without defects in an appropriate die shape with the 590 MPa steel sheet. By using the heated steel sheet, the cracks was prevented, and the joinabilities were improved. In the tension-shearing test, the fracture occurred around the minimum wall thickness part in both the upper aluminum alloy casting and steel sheet.