热轧H型钢控制冷却过程换热规律的研究

发布时间：2018-08-04 19:36

【摘要】：热轧H型钢控制冷却过程中的数值模拟经过长期的发展取得了很大的进展,但是在理论研究和工业应用方面仍然存在着很多复杂的问题:加热冷却过程中,工件表面与介质间发生强烈的换热,表面综合换热系数受工况影响较大,工件与冷却介质的状态不同、接触方式不同,即便是同一零件不同表面的换热系数都会有差异。如何准确的确定表面综合换热系数,对提高H型钢的加热冷却过程数值模拟的精度,控制和保证H型钢的轧制质量具有重要的意义。本文首先采用集总参数法和有限元Ansys模拟分析,验证了实验用圆柱型Q235探头符合一维瞬态传热,确保了它和H型钢的一维瞬态保持一致;其次利用圆柱Q235结构钢为探头,进行加热和三种冷却方式(水冷、空冷、喷雾冷却)下的温度曲线采集的实验,利用真彩无纸记录仪和仪表上位机管理软件获得其近表面热实测数据文件,将实验数据导入到Matlab中,并对实验数据进行拟合;再次采用非线性估算法,利用Matlab软件进行迭代编程,得到加热和三种冷却方式下的综合换热系数曲线;最后利用Ansys有限元软件建立加热和冷却过程的变物性、非稳态温度场的有限元模型,换热系数采用前述实验所得数据,对实验结果进行验证。该模型全面考虑了变热物性、相变潜热、相变动力学原理等综合因素的影响。并取部分节点研究其温度变化以及沿路径应力场的变化,得到了在实验数据基础上的新的H型钢温度场和应力场的变化规律。采用控冷新技术将对传统的型材生产工艺进行改造,对H型轧后控冷换热规律的研究是进一步提高控冷数值模拟精度和水平的关键性问题,对国民经济发展、资源合理利用,具有非常现实和深远的意义。
[Abstract]:The numerical simulation in the controlled cooling process of hot rolled H-section steel has made great progress after a long period of development, but there are still many complicated problems in theoretical research and industrial application: in the process of heating and cooling, There is a strong heat transfer between the workpiece surface and the medium, and the comprehensive heat transfer coefficient of the workpiece is greatly affected by the working conditions. The state of the workpiece and the cooling medium are different and the contact mode is different, even if the heat transfer coefficient of different surfaces of the same part will be different. How to accurately determine the surface heat transfer coefficient is of great significance to improve the accuracy of numerical simulation of the heating and cooling process of H-section steel and to control and guarantee the rolling quality of H-section steel. In this paper, the lumped parameter method and finite element Ansys simulation analysis are used to verify that the cylindrical Q235 probe accords with one-dimensional transient heat transfer, which ensures that it is consistent with the one-dimensional transient state of H-section steel, and then the cylindrical Q235 structural steel is used as the probe. The temperature curves of heating and three kinds of cooling methods (water cooling, air cooling, spray cooling) were collected. The real color paperless recorder and the instrument management software were used to obtain the data files of the near surface heat measurement. The experimental data are imported into Matlab, and the experimental data are fitted. Thirdly, the comprehensive heat transfer coefficient curves under heating and three cooling modes are obtained by using nonlinear estimation method and iterative programming with Matlab software. Finally, the finite element model of variable physical property and unsteady temperature field of heating and cooling process is established by using Ansys finite element software. The heat transfer coefficient is verified by the experimental data mentioned above. The model takes into account the influence of various factors, such as variable thermal properties, latent heat of phase transition and kinetic principle of phase transition. The temperature change and the stress field along the path are studied in some joints. Based on the experimental data, the variation law of temperature field and stress field of H-section steel is obtained. By adopting the new controlled cooling technology, the traditional profile production technology will be reformed. The research on the heat transfer law of the controlled cooling after H type rolling is the key problem to further improve the precision and level of numerical simulation of controlled cooling, and to the development of national economy and the rational utilization of resources. Have very realistic and far-reaching significance.
【学位授予单位】：辽宁科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG335.42

【参考文献】