Formability behavior of Al/steel MIG arc brazed-fusion welded joint

Abstract

5052 Al alloy plate was successfully lap-joined to galvanized steel plate by pulsed metal inert gas (MIG) arc welding with Al-Si filler wire. Formability properties of the Al/steel brazed-fusion welded joints with different welding parameters were characterized and investigated by bending and cupping tests. Sound weld appearance was obtained for all the fusion welded-brazed joint of aluminum alloy to steel in experiments, the average mechanical resistance of the joints reached up to 80% or so of that of the Al alloy base metal. The largest longitudinal face bending angle was 108°. There was an evident negative relationship between the welding heat input and the joint bending property. The formation of Fe2Al5Zn0.4 of intermetallic compounds (IMCs) at the brazed interface was an important influencing factor on the bending property of the joints. Based on the IMCs layer morphology, the fracture modes in bending tests were analyzed by three different paths of crack propagation owing to different welding heat inputs. During the cupping tests, surface crack initiation occurred in the heat-affected zone of the Al alloy side at welding heat input of 592 J/cm and the bulging drawing property was equivalent to that of the Al alloy base metal. The studies indicated the possibility and feasibility of manufacturing TWBs by the MIG brazed-fusion welding of Al alloy to steel.