1.No 1 Steelmaking and Rolling Plant， Maanshan Iron and Steel Co Ltd, Maanshan 243000, Anhui, China； 2.Metallurgy and Resources School，Anhui University of Technology，Maanshan 243002, Anhui, China
Abstract：The genesis of CSP cold rolled and galvanized sheet surface defect were studied. The result showed that the inclusion came from mold powder， deoxidizing result and refractory material caused the surface defect. Aiming at this situation， the argon bottomblowing and wire feeding were adjusted. The protective casting was improved and ladlechanging and adding mold power operation were normalized. The taper of mould narrow face was set 12％， and the slab thickness was changed from 72 mm to 90 mm. Implementing these ways， the surface defect of cold rolled and galvanized strip was controlled and the surface defect decreased form 9.97％ to 2.59％.
