Analysis of Stripe Defects on the Cold Rolled Aluminum Strip Surface
In the cold rolling production process, there are always bright, and dark stripe defects on aluminum strips surface when lubricated with rolling oil. The micromorphology and structure of defects were investigated by the surface profiler, OLYMPUS LEXT OLS4000 microscope, and SEM. The constituent elements of the aluminum surface were detected by EDS. The formation mechanism of surface defects was investigated. The analyses of the data suggested that the dark stripe was tougher than the bright stripe surface and the average surface roughness between them varies to 17.8%. The chemical composition of the residue was the significant difference in oxygen content. The oxygen content of dark stripe was much higher than the bright stripe defects. The reason for the difference may be that in rolling speed process, the oil film failed to spread uniformly in the vast areas of deformation zone infinite time which led to the rolling oil film thickness distributes unevenly. The areas of the surface with little rolling oil would suffer insufficient lubrication and cause rougher surface. Moreover, the fresh surface without rolling oil is more likely to be oxidized. The different roughness and composition lead to the difference in macro morphology which is the stripe defects on the surface of aluminum strips.
KeywordsCold rolling Process lubrication Surface defects
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