Three Dimensional Analysis And Crown Calculation Of Strip Hot Rolling

The main indicators of the quality of hot rolled strips include dimension, shape (crown and flatness), microstructure and property, and surface quality, in which strip shape is not only the primary concern and difficulty of the hot rolled strip quality control, but also one of the company's core techniques. In order to continuously improve the quality of hot-rolled strip shape, it is necessary to thoroughly study the roll deformation and flow characteristics of rolled metal in hot-rolling process, analyze of the influences of various factors on the shape, to provide a theoretical basis and data base for the establishment of precise shape control models.This paper systematically reviewed the development of production of hot-rolled strip and plate shape theoretical research, introduced the theoretical approach adopted by the research to elastic deformation of rolls, wear, thermal expansion and rolling plastic deformation. The paper utilized a three-dimensional simulation system to simulate a 1780mm hot strip rolling process, in which the split beam model (influence function method) is used to calculate the elastic deformation of rolls, the distortion differential method is adopted to calculate the thermal deformation of rolls, the theoretical statistical model is used to calculate the wear of rolls, the plastic finite element method is utilized to calculate the plastic deformation of metal. Based on simulation results, the elastic deformation of rolls during rolling process (bending and flattening), thermal deformation, wear, rolling pressure distribution, pressure distribution between rolls, calcaulated value has been compared with measured value.Based on the simulation results for hot rolling processes at different rolling conditions, the influences of bending force, original roll crown and strip crown on the rolling force distribution, force distribution between rolls, gap profile, thickness distribution and ex-tension distribution are systematically investigated.Determination of strip crown according to the roll conditions is the basis of shape research and on-line shape setting. According to the shape quality problems in a 1780mm hot-rolling process, the influences of various factors on strip shape have been analyzed through simulation rolling process. The work in the paper provides the important basis for the parameter optimizing and model modifying, improving the set-up and control precision of strip shape and solving the shape quality problems in the production.