Comparative Study on Mechanical Joints of Aluminum Vibration Damping Sheet and 1.5 GPa HPF Steel sheet

Abstract

In this study, the mechanical properties of aluminum vibration damping sheet and 1.5 GPa HPF steel sheet (SABC1470) dissimilar joining were evaluated. Joint methods of self piercing rivet (SPR), bolt/nut, flow drill screw (FDS), and blind rivet were compared to evaluate joint characteristic. In SPR Joining, buckling failure was occurred in SPR rivet caused by the strength of the 1.5 GPa HPF steel. So that, SPR hybrid joining was selected with a Al5052 alloy additional plate in lower sheet for formability and pre-hole processed on 1.5 GPa HPF steel in upper sheet. Through optimized of SPR die, the tensile shear load of the SPR hybrid joining was measured 7.53 kN. In FDS joining, failure of fastener was occurred due to the high strength of the 1.5 GPa HPF steel. FDS joining was available after pre-hole process on the 1.5 GPa HPF steel. However, delamination of the aluminum damping plate was observed and the tensile shear load was measured 3.14 kN. In bolt/nut joining, tensile shear load was measured depending on process variable (combination of plate, washer and tightening torque) and maximum tensile load was measured 5.43 kN. In blind rivet joining, the maximum tensile shear load was measured 3.64 kN, when the Al vibration damping sheet was placed on the upper plate. The large area of the blind rivet head released the concentration of stress on Al vibration damping sheet. As a result, SPR hybrid joining is considerable method because pre-hole processing is minimized and tensile shear load is higher than the other method.