Genesis and Control of Surface Sliver Defects of IF Steel Cold Rolled Sheets

Sliver defect is one of the most common defects in IF steel cold rolled sheet.In this paper,the genesis of cold rolled IF steel sheet sliver defects in Handan Iron Steel Group have been studied,and some methods of reducing sliver defects have been proposed. SEM-EDS result indicates that there are a large amount of small-sized Al₂O₃ particles in the sliver defects.According to SLIME results of slabs at different casting stages,there are high amount of large-sized Al₂O₃ inclusions in ladle changing and SEN changing slabs,which originate from the drop off of clogs in entry nozzle. Therefore,it can be concluded that the clogs in entry nozzle drop off into mould and develops as a large-size Al₂O₃ inclusion in the slabs,which causes surface sliver defects during cold rolling process.