Effect of machining process on the joint strength of friction welded joint of 6061 aluminum pipe and S25C carbon steel pipe.

Comparatively thick pipes of 6061 aluminum alloy and S25C carbon steel were friction welded under a preferable welding condition and the strength distribution on the weld interface was investigated. The results obtained are as follows; (1) According to a decrease of the thickness ratio 0.30, 0.16, 0.15, 0.14, 0.13 and 0.12, the joint efficiency decreased 73.9%, 68.1%, 63.8%, 55.8%, 39.9% and 21.6%, respectively. (2) Friction welding of thin pipe having less thickness ratio t/D0 than 0.11 was difficult to produce a sound weld (D0: outer diameter, t: thickness of pipe). (3) The tensile strength of each 11.1% area from inner and outer edges of the weld interface was low, and the joint efficiencies were 30∼50%. (4) The joint efficiency of the joint removed inner and outer areas of the weld interface was about 95%.