Abstract: Due to the limit in reduction of heay plate, many problems (such as internal defects, the unfavorable microstructure)could not be eliminated by conventional rolling and cooling method. We developed a novel rolling technique called gradient temperature rolling to produce heavy plate. Firstly, fast cooling was carried out on billet before rolling to obtain an appropriate temperature gradient in thickness direction, which results in large deformation in billet center during rolling, so uniform deformation and homogeneous recrystallization could be achieved. As to ultra-heavy plate with high strength, this novel rolling technique was employed as well as intercritical quenching and tempering in this paper. The developed heavy plate with yield strength of 690 MPa was produced and represented an excellent elongation and low temperature toughness, and the maximum difference of yield strength was less than 13 MPa in full thickness indicating that an outstanding strength homogeneity was achieved.
Authors: Bao-Sheng Xie, Qing-Wu Cai, Yang Yun, and Xu Chen
Keywords: Tempering, High Strength Steel, Gradient Temperature Rolling, Intercritical Quenching, Ultra-Heavy Plate, Mechanical Property, Microstructure