In this study, SM45C-STKM13B hollow shaft of different thickness was joined by friction welding. After friction welding, we treated to specimen of annealing(post-weld heat treatment). The specimens were tested as-welded and post-weld heat treatment(PWHT). The mechanical properties including tensile test and vickers micro-hardness were examined. And then, the mechanical properties were compared for as-welded and PWHT in SM45C to STKM13B. Microstructure of joining part were examined in the weld interface and weld region and heat affected zone and base metal of weld parts.

Recently, applied areas of nonferrous materials have been expanded in terms of efficiency of materials used and cost reduction. And, in accordance with compactness and accuracy of parts, the need of joining of dissimilar materials is raised. Accordingly, this study aimed at finding out the optimal welding current value(6.3～6.5kA) considering tensile strength, fracture test and welding residue after joining with various welding conditions by means of copper pipe(Φ7.0 × t0.5) and aluminium pipe(Φ7.0 × t0.7) using an eutectic diffusion bonding machine.