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The main surface features found during cold rolling of initially twin-rolled cast aluminium are grooves, gorges, shingles, cross hatches and rolling ridges. Grooves–shingles are formed at the exit side of the neutral plane during casting and these are deformed into gorges in the first pass and the shingle is smeared over the cavity. A large number of shingles are formed in the second pass from steps in the surface resulting in interfaces within the surface region. Due to the following extension of the sheet and the shift in rolling direction these interfaces will be extended and new interfaces formed by additional smearing out of steps, resulting in a laminated structure in the surface. Cross hatches are formed in these laminated areas. Later passes cause the cross hatches to grow and new ones to be formed.