Development of Aluminum-Steel Cladding Strip with Pre-Cladded Brazing Layer Used in Air Cooling System of Power Plants

The brazing layer of 4343 aluminum alloy was hot rolled with cladding layer of 4A60 aluminum alloy. The as-rolled sheet and 08Al steel were cold rolled at a single-pass deformation of 50% by the rolling mill with diameter of 420 mm and annealing treated at 520 ℃ for 24 h, then the aluminum-steel cladding strip with pre-cladded brazing layer, used in air cooling system, was prepared and the microstructure and mechanical properties were studied. The results show that the microstructure of 08Al steel layer was consisted of recrystallized ferrite. The yield strength of the cladding strip was above 250 MPa, the tensile strength was 305 MPa and the elongation was more than 30%. After the cladding strip was brazed at 608 ℃ for 20 min, IMC (Intermetallic Compound) at aluminum-steel interface was not found. The brazed cladding strip was fractured in the layer of 4A60 aluminum alloy in tensile-shear test and the delamination was not observed at the interface between 4A60 aluminum alloy and 08Al steel.