Abstract: The CMT (cold metal transition) welding-brazing of 6082 aluminum alloy and Q235 steel with AlSi5 flux-cored wire was carried out.The microstructure and mechanical properties of the welded joints at different welding speeds were analyzed.The results show that the flux of AlSi5 flux-cored wire improves the wettability of the molten aluminum alloy on the surface of Q235 steel.Fe₂Al₅ and Al₈Fe₂Si intermetallic compounds are formed at the interface layer between 6082 aluminum alloy and Q235 steel.Meanwhile, with the increase of welding speed from 450 mm/min to 550 mm/min, the thickness of the interface layer between aluminum alloy and low carbon steel decreases gradually, and the tensile strength of the joint increases first and then decreases.When the welding speed is 500 mm/min, the tensile strength is up to the maximum of 159 MPa.