Study of mechanisms of cold roll welding of aluminium alloy to steel strip

Abstract

The mechanisms of cold roll welding of aluminium alloy to steel strip has been assessed based on a study of interfacial behaviour at deformations of up to 60% together with the surface characteristics of peeled Al clad steel strip. The proposed mechanisms are applicable where the contact surfaces are degreased and then scratch brushed before the rolling deformation. According to this mechanisms the scratch-brushed layers are fractured shortly after entering the roll gap at a reduction of approximately 10%, which is about the threshold deformation for the roll bonding of aluminium to steel. The transfer cracks formed then become wider so that the distance between each coherent block increases as the rolling deformation increases through the mill. This process allows the bond to be established between the underlying areas, termed as virgin metal, of base metal, which are extruded between the cracks at the scratch brushed regions.