1. State Key Lab of Rolling and Automation, Northeastern University, Shenyang 110819, Liaoning, China 2. Qinhuangdao Shouqin Metal Materials Co., Qinhuangdao 066326, Hebei, China
Abstract:The behavior and critical condition of defects closing during Q345 ultra-heavy plate rolling with 400mm thickness continuous casting slab were investigated with FEM, ANSYS/LS-DYNA. The results show that the central rectangle defects in ultra-heavy plate will be closed by enough pass reduction ratio. The defects size, roll radius and slab thickness have obvious influence on critical reduction ratio. The critical reduction ratio is inversely proportional to defect size and roll radius but is proportional to slab thickness. In the hot roll mill of 1120mm×4300mm, the critical closing reduction ratio for the central rectangle defects to be closed in the first pass is 15.8%, changing into geometric parameter 0.511; meanwhile, closing central defects with critical reduction ratio has better effect. At last, the defects closing test verifies the results of simulation.