Abstract：A problem occurred that a lot of surface crack defects appeared on the center of strip during the rolling process of thick gauge S275JR hot rolled strip steel in the plant. The macroscopic feature, chemical composition, metallographic structure of the defect were studied and results showed that this kind of surface crack defect was caused by the micro-crack on the steel slab surface. Based on this analysis, the ［S］ content, superheat, mold cooling intensity and mold powder were optimized during S275JR production. Industrial practice showed that the surface crack defects rate was decreased from 12% to 0.93% after the technological improvement.
2016, Vol. 26 
