Study on the control of post-roll bending deformation and residual stress in hot-rolled L-beam based on rapid cooling

The bending deformation problem and internal residual stress of hot-rolled L-beams affect the quality and subsequent use performance of L-beams. In this paper, the computational model of the L-beam air-cooling process is established by using ABAQUS finite element software, which reveals the reasons for three times deformation of the L-beam from the perspectives of phase change expansion and metal cooling contraction. In order to control the deformation and residual stress of the L-beam, four experimental schemes were determined with the cooling method, water pressure, and the opening and closing state of the cooling unit of the cooler as variables. The temperature distribution, deformation before straightening, warping deformation after cutting, and magnetic field distribution curves of L-beams before and after rapid cooling under different experimental schemes were examined, and the microstructure and properties of L-beams were examined and the results were analyzed. The results show that the cooling uniformity of the L-beam can be improved by rapid cooling, which can effectively reduce the amount of bending per meter of the L-beam before straightening, the amount of warping deformation after cutting, and reduce the level of residual stress inside the L-beam, and at the same time can refine the microstructure and improve the properties. In this study, the amount of bending per meter and warpage deformation after cutting of L-beams were reduced by up to 67.3% and 85.7%, respectively, and the maximum value of the magnetic field gradient associated with the stresses in the L-beams was reduced by up to 80.2%.