Investigation of Orange Peel Defect Generating During Hot Rolling Process

The market capitalization of the cold rolled sheets is continuously increasing in the automotive industry. The production of defect-free cold rolled steel sheets requires increasingly more stringent norms for defects that are not visible in sheet form but are visible post forming processes. The present case deals with a rough surface defect on cold rolled product upon stamping. Using optical microscope and Ericson cupping testing, we have characterized the defect, and observations were correlated with plant operational and process parameters for its likely origin. The defect was characterized to give a) higher carbon and thereby higher un-stabilized free carbon and b) abnormally developed coarser grains. Authors have used deductive reasoning in eliminating the probable causes to arrive at the root cause of the defect observed. Based on the findings, plant trials were taken with certain recommendations to verify for effectiveness of the solution.