The Effect of Continuous Casting Cooling Process on the Surface Quality of Low‐Nickel Austenitic Stainless Steel

This study comprehensively employs data analysis, simulation, and characterization techniques to investigate the causes of surface spalling defects in low‐nickel austenitic stainless steel. The results indicate that there are components of mold fluxes at the defect location. Correlation calculations of the smelting process demonstrate a significant association between the fluctuation of the mold cooling water temperature difference and the occurrence of defects. This is attributed to the reduced heat transfer in the mold caused by using mold fluxes with higher basicity and lower viscosity, which leads to slab cracks and defect formation. The construction of a continuous casting temperature field model reveals that reducing the cooling water flow in the secondary cooling roll section of continuous casting can effectively mitigate defect severity. This is attributed to the fact that intense cooling of steel grades can lead to slab deformation, resulting in stress concentration and an increased subsequent temperature recovery range, which in turn causes slab cracking and defect formation. In production, it is essential to ensure the compatibility of the mold fluxes and to adopt sufficient roll weak cooling, as well as to control the temperature rebound range during the cooling process to reduce the occurrence of defects.