Research on the Evolution Behavior of Surface Transverse Cracks During the Hot Rolling Process of Medium Plates

摘要

The evolution of transverse cracks in slabs during rolling may severely affect the quality of rolled products. One method used for medium plates is reverse breakdown rolling; however, there is little reported in the literature regarding this technique. Further research on the evolution of surface transverse cracks during processing is necessary. The present study investigates the evolution of cracks with different depths during reversing rolling, as analyzed by finite-element simulation and laboratory experimentation. Analysis focused on the stress field and microstructure surrounding a surface transverse crack during the rolling process. Results showed that crack edges opened and became part of slab surfaces as the number of rolling passes increased. Surface transverse cracks of varying depth change shape in a similar manner; however, by analyzing the change in the ratio of width and height, it was observed that the width changes more quickly than depth as the number of rolling passes is increased. Simulation results show that in the rolling direction, there is always a tensile stress around two edges of a surface transverse crack during the reversing rolling process. The results demonstrate favorable agreement between experimental and simulated results.