Abstract:The dissimilar metals of 1060 aluminum alloy and galvanized steel were joined with lap joint by pulsed double electrode gas metal arc welding-brazing with 4043 aluminum filler metal. The welding joints of aluminum and steel were then annealed at 350 ℃. The distribution of alloy elements in the welding joint different zones before and after annealing treatment was analyzed by map scanning, and the corrosion behavior of the welding joints was investigated by immersion corrosion tests and electrochemical corrosion tests, the corrosion behavior of the welding joints different zones and the effects of annealing treatment on corrosion property of welding joint were analyzed. The results show that the homogenization diffusion of Si elements in weld seam occurs after annealing treatment, meanwhile, the thickness of Fe₂Al₅Zn_0.4 of zinc-rich zone increases significantly. In addition, the galvanic corrosion occurs when the samples are immersed in corrosive media, the whole steel of welding joint is corroded drastically and displays a homogeneous corrosion, however, the dissolution of weld seam is slight. The intermetallic phases at the interface reduces the corrosion property of welding joints. Further, the results indicate that zinc-rich zone of weld joints is most prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed by map scanning on the basis of the test results.

Key words: aluminum-steel welding-brazing; galvanic corrosion; intermetallic compounds; zinc-rich zone