Friction welding of 6061 aluminum alloy and steel was conducted. Sound welds were produced in all A6061/steel combinations, and tensile fracture occurred in thermal softened A6061 area. Joint strength depends on the width of this softened A6061 area. Tensile strength of T62 heat treated joint was high compared with that of the weld joint.
Friction welding has been widely used for welding of similar and dissimilar metals. However, in friction welding of dissimilar metals, such as aluminum alloy and steel, brittle intermetallic compounds tend to form making it very difficult to obtain a sound weld (Elliott and Wallach, 1981). Presently, the demand for friction welding of such materials is increasing in many industrial fields. Thus, in order to produce a sound welded joint between such metals, friction welding was undertaken using an insert metal (Sassani and Neelam, 198g), (Ochi, ct al, 1995). In such a case, the problem is to increase welding process, in this study, the direct friction welding of low-weldability aluminum alloy and steel was conducted, and suitable welding conditions for producing a sound weld were investigated. In particular, the effects of softened aluminum alloy on the joint strength were examined. Moreover, the effects of various heat treatments of the welded joint on the joint strength were examined.
The materials used in this investigation included 6061-T6 aluminum alloy (A6061), $15C, $25C, $35C, $45C and $55C carbon steels and SUS304 stainless steel (AISI 304). The chemical compositions and mechanical properties of the base materials are shown in Table 1 and Table 2. The welding materials were machined to the shape and dimensions shown in Fig. 1. Friction welding was carried out using a brake-type friction welding method. The effects of the welding conditions (friction pressure P, forge pressure P2, friction time.
