Comparison between conventional and cross shear roll bonding of aluminium to mild steel.

The process of cold roll bonding two dissimilar metals may be divided into three phases through the roll gap, from the entrance to the exit, i.e. the sliding phase, seizing phase and bonding phase. In conventional roll bonding the two identical work rolls are driven at the same peripheral speed, whereas in cross shear roll bonding the two identical work rolls are driven at different peripheral speeds, thereby a shear zone in the central region of the roll gap will be established in the latter case. By placing the harder metal in contact with the faster roll, the relative sliding at the interface between the two metals is enhanced at the entrance whereas the plastic flow of the two metals becomes more homogenous at the exit of the roll gap. Both of these factors facilitate bonding.