Study on welding process and mechanical properties of resistance spot brazed pure aluminum 1060 to galvanized steel

Resistance spot brazing of pure aluminum 1060 to SGCC hot-dip galvanized steel was investigated. The microstructure of the intermetallic compound (IMC) in the interfacial layer was analyzed, and the mechanical properties of the joint was tested. The results showed that the aluminum-silicon brazing filler metal had a well wettability, and the intermetallic compound with double-layer structure and uneven thickness less than 10 μm generated at the interface of the welded joint. When the welding current was 7.8 kA, the maximum tensile shear load of the joint was 4.72 kN, which was significantly higher than that of the resistance spot welding joint under the same process parameters. The fracture of the joint mostly occured on the side of aluminum plate, and it was mainly in the heat affected zone (HAZ) rather than the welding spot, indicating that the resistance point brazing joint was of good quality. However, the local incomplete brazing was found in the weld interface at the aluminum side, where the tensile stress was generated, and the weld interface tended to crack under the stress of the intermetallic compound.