Development of joining process between aluminium alloy and stainless steel by using plastic flow in automotive parts

Abstract

In recent years, a lot of process innovations are strongly required for cost and weight reductions in addition to upgrading driving performance and reducing greenhouse grasses in automotive industry. In case of manufacturing automotive parts, a number of materials are used to satisfy their high accuracy and cost reduction. Dissimilar metal joint such as combination of aluminium alloy and austenitic stainless steel is increasing to apply them based on this background. In this joint, an index to guarantee the quality is indispensable, because the formation of intermetallic compounds introduces brittle fracture at the interface between two metals. It is described that plastic flow is applied for dissimilar metal (aluminium alloy and stainless steel) joint in this paper. Based on this research, it is possible to control the break point by forming projection on aluminium alloy. Projections are formed to promote the plastic flow and they are formed by keeping aluminium alloy on softening temperature. It is clear that joint boundary is composed of two reaction layers, one contains Al–Fe–Si–O and the other contains (Fe–Cr–Ni) Al3 intermetallic compound. The new process described in this paper is available for application to production line of various precise sensors for automotive parts.