Surface Finish Enhancement of Hot-Rolled Strips on the 2000 Wide-Strip Rolling Mill Using Mathematical Modeling at Novolipetsk Steel

Based on the manufacturing of rolled stock with a high-quality surface finish on the 2000 wide-strip rolling mill at Novolipetsk Steel (NLMK) using a package of mathematical models of energy–power and thermal finish-rolling conditions, the formation mechanisms of morphologically similar mass defects of the “pitted surface” type have been analyzed. The influence of the roll and strip cooling conditions from the rolling temperature conditions has been investigated. The factors that enable the mill scale to be rolled into the strip in the first stands of the finishing train have been identified. The cooling conditions for rolling of critical-duty products have been developed and introduced in the 2000 mill finishing train, which ensured a 36%‑yield reduction of products in 2018 that exhibited the “pitted surface” defect.