Aluminum alloys are applying for civil engineering fields as a structure material. Non-heat-treatable aluminum alloy 5083-O, which has high strength and corrosion-resistance, excellent weldability and low temperature behavior and seawater resistance, is widely used for a civil engineering material. In this study, first, a technique to apply high-frequency induction heating to friction welding as an auxiliary heat source was developed. Then, friction welding experiments were conducted for 5083-O rods with this technique. The experiments were carried out under different temperatures by preheating with the induction heating, and the relation of the joint strength and the preheating temperatures was investigated. In order to understand the effect of the preheating on increased joint strengths, material structures of the joints were analyzed. Besides, the effects of induction heating to the welding parameters while friction welding were investigated. As a result, when using the induction heating while friction welding, the areas of plastic flow at the joint portions broadened to enhance the strength of the joints.
