Analyzing and Control of Surface Inclusion Defect of Hot-Rolled Coil

This paper is considering the surface quality control of hot-rolled coil. Through analyzing patterns, distributing-regularities and components of surface defect of low-carbon coil of WISCO, got the conclusion that mould powder entrapment was the key factor that lead the defect’s occurrence. Based on discussing the mechanism of powder entrapment in mould, developed a type of high viscosity powder, optimized flow field of mould through modifying the structure of SEN, and improved other relevant process conditions, the incidence rate of this type of defect was under controlled effectively and the degradation rate of the coil caused by the defect dropped from about 4 percent to less than 0.2 percent at the end.