Strength and Formability of Friction Stir Welded Aluminum Alloy with Cold Rolled Steel
Tatsuro MORITA, Akira SAKAMOTO, Shinta MABUCHI and Takashi IIZUKA
Abstract:Friction-stir-welding (FSW) was conducted between an aluminum alloy 6061-T6 plate and a cold-rolled steel SPCC plate. Tensile and fatigue strengths of the FSWed material were investigated and its formability was estimated through bending and deep-drawing tests. Furthermore, we investigated effect of aging treatment (18ks, 453K) after FSW. The result showed that the condition of FSW was suitable and no brittle compound and defects were found at the interface between the 6061 alloy and SPCC steel. However, hardness decreased in the region where the rotating tool passed so that the tensile strength of the FSWed material was slightly lower than that of uniform 6061 alloy. The tensile strength of the FSWed material was recovered by aging treatment and it reached to the same level to the 6061 alloy. The FSWed material and its aged material possessed good bending and deep-drawing formability. However, the fatigue strength was decreased even after aging treatment because an insufficient joining region was inevitably formed by FSW at the opposite side where the rotating tool traveled. Key Words:Friction Stir Welding, Aluminum Alloy, Cold Rolled Steel, Tensile Strength, Fatigue Strength, Formability, Bending, Deep Drawing, Sustainability