Al 7075 합금의 마찰교반용접 용접성연구

A Weldability of Al 7075 Alloy Welded by Friction Stir Welding

Among light alloys, compound metal of aluminum has been applied widely on account of light weight and specific strength, but the aluminum alloy can bring about deformation by welding heat and defects such as porosity and crack easily in case of manufacturing structure by melting welding. In addition, intensity of joint can be deteriorated easily, so new technology is demanded. In 1981, TWI developed Friction Stir Welding, non-melting progress and this progress has been expanded into various industries widely. FSW technology, originated from friction welding, is in the limelight of a welding method which causes little deformation, is non-consumable, and supplies high quality joint without welding defection, fume, noise and harmful light. In this study, principle and characteristics of FSW with Al 7075 alloy among various aluminum alloys are investigated and analyzed by using technical characteristics of FSW as a new method which can solve the problem of melting welding of aluminum alloy. The experiment is carried out with Al 7075 made by ALCOA EUROPE with thickness of 8mm, tool which ㎜ has pins 7.5㎜ in length with stirring speed for 400, 600, 800 rpm with welding speed for 2, 1㎜/sec. 6 specimen was produced after friction welding experiments, changing each condition. After welding experiments, macroscopic test, tensile strength, and hardness are investigated and analyzed.