Analysis of Peeling Defect on the Surface of Cold-rolled Strip

The cause of peeling defect on the surface of cold-rolled strip, the formation mechanism of peeling defect were analyzed with scanning electron microscope (SEM), energy disperse spectroscopy (EDS) and metallographic microscope, and the main measures to control peeling defect were explored. The results show that the main causes of surface peeling of cold-rolled strip are inclusions, subcutaneous bubbles and scratches. The inclusions are mainly mold slag, slag formed by refractory materials, and the reaction product of oxides and slag in steel. By improving the purity of molten steel and controlling the composition of molten steel, inclusions in steel can be reduced. The bubbles in the matrix escape from the surface under the pressure during rolling, result in pinhole or honeycomb defect. By shortening the retention time of molten steel in the air and ensuring the quality of argon blowing can reduce bubble defect.In the process of uncoiling, coiling and lifting of steel coil, the relative sliding between the steel coil layers will cause scratch defect, which can be avoided by adopting reasonable working units and process parameters.