Research Of Multi-Pass Plate Hot Rolling By Mathematic Model

In order to keep up with the global competition, the predominant aim of rolling technology is directed toward the development of lower cost, better quality and more varieties of product. But how to achieve these targets is an important subject to the Iron & Steel filed. The mathematic model mentioned in this paper, includes three main parts: temperature solution module, rolling pressure module and strain module. Basic on this model, the method of inverse determination of thermal boundary parameters is studied and a new flow stress input module is added to the existing program.Firstly, an interpolation module is established for the calculation of rolling force. In this module, the influence of temperature variation and work hardening is better expressed compared to the traditional theory and calculated model. Also, it has better performance than those empirical formulas. Stress can be calculated based on certain data and the range of applicability is expanded.Secondly, the coefficients of heat film convection are inversely determined by trail and error method. This can improve the precision of calculation and be helpful for rolling schedule optimization. Distribution of temperature field is an important factor during the simulation; and it affects the calculation of rolling stress directly. A temperature analytical model is derived by using series function solution, the coefficients in which for successive processes are smoothly transformed from the former process to the next. Therefore, the continuous computation of temperature for multi-operation and multi-pass is accomplished.Thirdly, by comparisons of calculated results with experimental data, it indicates that, the modified mathematical model is able to reasonably represent the temperature variation and the rolling pressure. Also, the hot-rolling technique parameters fit the practical rolling process and can be calculated for optimization of rolling schedule. The result can be used to improve the product quality and prolong the lifecycle of hot-rolling machine.