Microstructure and Properties of Q960 Steel/6061 Aluminum Alloy MIG Welded Joint

The effects of welding parameters on the MIG weld forming of Q960 steel/6061 aluminum alloy and the microstructure, phase composition of interface and tensile properties of the welded joints were studied. The results show that the weld penetration, weld width and reinforcement of Q960 steel/6061 aluminum alloy MIG welding joint increase with the increase of welding current and decrease with the increase of welding speed; the interface zone consists of Fe₂Al₅ phase near Q960 steel side and Fe₄Al₁₃ phase near 6061 aluminum alloy side. The better forming effect can be obtained when the welding current is 85-125 A and the welding speed is 35-55cm/min. When the welding current is 105 A and the welding speed is 45cm/min, MIG welding joint with good quality can be obtained, the tensile strength is the maximum. The fracture position of the joints is located in the interface area, which is mainly related to the hard brittle intermetallic compound Fe₂Al₅and Fe₄Al₁₃ in the interface area.