Multi-field Coupled Numerical Simulation And Experimental Research Of Rolling Process For50kg/m Rail

Rail has experienced more than240years of development history since1767. It iswidely used in mine transportation, passenger and freight rail transportation and cranetransportation. The type of rail is various in our country, and their properties are different.Its inherent quality is directly related to the safety of the railway transportation. It hasgreat significance that studying how to improve the production efficiency and quality ofthe rail under the conditions of the existing production equipment.In this paper, U71Mn steel is chosen as the rail’s material. The single-passcompression test and the double-pass compression test for the material were done on theGleeble-3500thermomechanical simulator, and the grain’s size of the specimen afterquenching treatment was measured. From the comprehensive analysis of the experimentaldata, the laws and mathematical expressions of dynamic and static recrystallization forU71Mn steel have been obtained under conditions of different temperature anddeformation.Taking50kg/m rail-rolling production line as the object of study, using softwarePro/Engineer to establish the three-dimensional solid model of the roll and billet, thewhole process of the12rolling passes were simulated by the finite element softwareDEFORM-3D. Through the multi-field numerical simulation which include thermo,mechanics and the evolution of microstructure, the parameters of the stress field, strainfield, displacement field, temperature field and microstructure evolution at each momenthave been obtained. The way to optimize the pass system has been proposed, and anappropriate initial rolling temperature has been selected.The microstructures which phase transition generated during the rail cooling processwere simulated, and the simulation results have been verified by metallographicexperiment. The study found that there is martensite stucture in addition to pearlite. Thepotential harm and the reasons for the formation of martensite have been analyzed, and theway to eliminate martensite and improve the microstructure of rail has been proposed.The results of this study will help to improve production processes in rail production, formulate rolling procedures, predict the properties of product, and finally achieve thepurpose of production high quality rail.