Abstract:

Because of many advantages such as light weight, superior comprehensive property and so on, the Al alloy/steel composite structure has abroad application prospect in industries such as automotive, aerospace, petroleum and petrochemical, energy and shipbuilding and so on. But the great differences of physical and chemical properties between Al alloy and steel make that there are some serious problems in joining Al alloy to steel. Brazing-fusion welding can be realized based on the difference of melting point between the dissimilar metals. In welding process, by precisely controlling heat input, both the metal with lower melting point and filler metal melt and form the fusion welded joint, while the metal with higher melting point does not melt and forms the brazed joint with the molten base metal and filler metal. This welding methods can bring out the potentials of properties for every metals and is very suitable for high efficient and high strength joining of Al alloy to steel. The state-of-art of brazing-fusion welding of Al alloy to steel were summarized from welding processes, the control of joint microstructure and properties and basic theory and so on. The problems in joining Al alloy to steel are discussed, and the measures to promote the engineering applications of Al/steel joining technology are proposed. The overview can help to understand and develop brazing- fusion welding processes of Al alloy to steel, and promote its application in engineering.

Key words: Al alloy/steel, brazing-fusion welding, joint properties, state-of-art, joining of dissimilar materials