Experimental and numerical studies on flow behavior of surface defects in the heavy rail rolling

Purpose Surface defects are often present on the surface of continuous casting slabs and rolled products. A lot of surface defects of hot rolled products are inherited from initial defects on continuous casting slabs. This work aims to trace the original surface defect during the whole heavy rail rolling and avoid black line surface defect that appears on the surface of heavy rail finial product. Design/methodology/approach Artificial round hole-shaped surface defects on the surface of continuous casting slab during the hot rolling of 60 kg/m heavy rail are analyzed experimentally and by means of explicit dynamic finite element method (FEM) and modified model rebuilding method. Findings The calculated results of surface defect locations of heavy rail finial product are in good agreement with the experimental ones. It is shown that the explicit dynamic FEM and modified model rebuilding method can be used effectively to predict the flow behavior of surface defects in the hot rolling of 60 kg/m heavy rail. Originality/value The three-dimensional finite element model for whole heavy rail rolling is built using explicit dynamic code and modified model rebuilding method. Flow behavior of black lines is studied in the 60-kg/m heavy rail rolling. The simulation results of six typical points are in good agreement with the experimental results.