Ridge and ridge-buckle defects in cold rolling

摘要

Ridge-buckle defect sporadically afflicts the cold rolled thin strip for more than 40 years and reveals as a protuberance on the coil and sinusoidal pockets in the uncoiled product.This defect can be traced back to the formation of ridge(high spot)in hot rolled coil.In the paper,a set of mathematical models capable of calculating the extent of ridge deformation in cold rolling and temper rolling,and corresponding stress concentration in a wound coil,have been developed to explain the occurrence of ridge-buckle defect in cold rolled thin strip.The sensitivity of the ridge-buckle defect of cold rolled thin strip to hot rolled coil profile containing ridge has been investigated in details.A permissible tolerance of ridge height in hot coil profile,which does not produce the ridge-buckle defect in subsequent cold rolling,was recommended.