Aluminum alloy has the characteristics of low density, corrosion resistance, wear resistance, high specific strength and specific stiffness, good impact resistance, easy surface treatment and good processability and formability. As countries around the world pay more and more attention to the lightweight of ship structures, the application of  aluminum-steel structural transition joints in shipbuilding or ship maintenance is becoming more and more in-depth and extensive.

Since the thermophysical properties of steel and aluminum are very different, it is difficult to weld them directly. The application of "aluminum alloy-pure aluminum-steel" transition joint for steel-aluminum structure welding can effectively avoid contact welding of steel hull structure and aluminum alloy hull structure, and can meet structural continuity, airtightness and certain strength requirements. At the same time, it also has the advantages of reliable welding quality and low operating requirements.

Aluminum steel structural transition joint, the temperature of this joint is generally <300℃. If titanium is added between aluminum and steel, both
aluminum-titanium-steel transition joints are used, the bonding strength and conductivity can remain unchanged when the service temperature reaches 450
℃.