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Multi-Parameter Coupled Simulation Of H-Beam Rolling And Experimental Study

Posted on:2007-07-05Degree:DoctorType:Dissertation
Country:ChinaCandidate:H B XieFull Text:PDF
GTID:1101360212495406Subject:Mechanical design and theory
Abstract/Summary:PDF Full Text Request
H-beam is widely used in the construction of national economy in virtue of its excellent section properties. With the development of production and application of H-beam in our country, increasing requirements are raised on product specification variety and close tolerance of shape and dimensions. In recent years, however, more and more attentions have been paid to the correctness and homogeneity of microstructure and property of product. To meet the society demands and the competitive market, it is therefore increasingly important to control and improve the microstructure and property of product, meanwhile shorten the lead time and reduce the development and production cost. Advanced development tools are needed to enable them design and analyze the steel product and rolling process in an efficient and productive manner. With the development of computer technology, numerical simulation has gained widespread application in rolling. Mathematical models of H-beam rolling based on the fundamental principles of continuum mechanics, heat transfer, and physical metallurgy can provide more scientific and effective tools for the design and control of rolling process to obtain steel products with desired shape, dimensions, and mechanical properties.Various phenomena such as mechanical, thermal and metallurgical changes occur during the H-beam rolling, and there exists complex interplay between them. Accurate modeling of H-beam rolling therefore requires a rigorous treatment of the coupling relation. This dissertation studies the deformations and microstructures evolutions of H-beam during hot rolling by means of computer simulation technique and experimentation. Based on systemic investigation of production of H-beam, the progress in theoretical research of hot rolling and metallurgical aspects, a comprehensive investigation is conducted into the elastic-plastic FEM theory, the regularity of metal flow in H-beam rolling, the property of heat transfer and further development of general FEM software. Taking the multi-physical process coupled and three dimensional nature of H-beam hot rolling problem into consideration, a model with elastic idle vertical roll for H-beam rolling process is established.The further development of MARC software is used in this dissertation. User subroutines of heat-machine coupling and multi-parameter coupling are developed for yield stress with the model presented by Guan kezhi and the microstructural evolutionmodel based on incremental formulation proposed by Yanagimoto. Another user subroutine of heat transfer coefficient is developed based on the specific heat diffusion at boundaries of H-beam, the heat transfer coefficients and radiation angular coefficients are derived and calculated under air cooling conditions. The simulation of heat-machine coupled and multi-parameter coupled for H-beam rolling process is achieved, after which the stress field, strain field, thermal field, metal flow and microstructural evolution in H-beam rolling are analyzed. The result of the study are very valuable to determine the process parameter of H-beam rolling in fact.Experimental investigations of H-beam hot rolling are carried out on the three-stand universal H-beam mill in the Rolling Lab of Yanshan University. The rolling force, rolling torque, surface temperature variation, microstructural evolution are recorded during rolling under different rolling schedules. Comparisons between measured values and simulation results show the correctness of presented theory. The research findings can provide significant reference for the determination of H-beam rolling parameters, and proper control and improvement of product shape and dimensions, microstructure and mechanical properties are expected to be made with the help of the model developed...
Keywords/Search Tags:H-beam, Universal rolling, Microstructural evolution, Multi-parameter, Numerical simulation, Elastic-plastic finite element, MARC
PDF Full Text Request
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