With three-step method “surface process + cold rolling bonding + annealing treatment"

i. e. first

treating the surface of 4mm 08 Al steel strip (/% : 0. 01G

0. 018A1) and 0.23 mm 4A60 aluminium strip by brushing

then single pass-rolled by 60% reduction for the aluminium-steel strip using high precision Φ420 mm four high rolling mill with 30 kN forward tension to get large deformation cladding

and annealing treatment at 520 ℃ for 24 h in a bell type annealing furnace

the cold-rolled 1. 7 mm 4A60 aluminium-08Al steel cladding strip with 80 〜90 μm extra-thin cladding layer is developed. The microstructure of 08Al steel in cladding strip is equiaxed ferrite with average grain size 15 μm

its tensile strength ≥320MPa and elongation ≥28%

and the bending properties of cladding strip also meet the requirement of standard. The intermetallic compound is not found in aluminum-steel interface region of cladding strip brazed at (600 ± 10) ℃

and the delamination phenomenon is not observed at interface of aluminium and steel.