What is it?

Mill shearing occurs when a strip of the base metal is torn off during the rolling process. The strip can potentially reattach as the process continues. This occurs due to over-rubbing of the steel as it is rolled. The overheating from this excessive rubbing causes the metal to shear off, and usually occurs in multiple instances. Mill shearing can be detected visually and is often mistaken for slivers, scabs, laps, and seams.