Numerical Simulation Study Of The Rails In Afterheat Quenching Process On-line

China’s railway construction entered a new developing stage of high-speed, heavy-duty to meet the requirements of economic development, which led to the rail qualityrequirements more and more stringent. Meanwhile, the improvement of productionefficiency has become the decisive factor of the development of modern enterprises. Sofar, on-line quenching that steels with the waste heat after hot-rolling was directlytransferred into a cooling device for quenching, is one of the most advanced productiontechnology and can greatly improve the production efficiency and save more energy.3D transient nonlinear finite element analysis model for U75V rails has beenestablished in the thesis, using ABAQUS, the nonlinear finite element analysis software.Rail on-line quenching process was simulated, and the intensity and the time in theprocess of the rails quenching was deemed as the main consideration according to theactual production process. A new theory educed from the analysis of temperature field,stress field and bending deformation under different cooling conditions would lay thetheoretical foundation for the optimization of rail quenching process.The conclusion can be deduced as follow, based on calculation and analysis that havebeen done in this thesis: Uniform temperature field of rails can be obtained bycontrolling either the quenching intensity or the cooling time of the rail flange. Thedeflection of rails can be well controlled by adjusting the quenching time and adding thecooling fog in the second half of quenching process, and exposing rails to cooling fogafter entering the cooling device for55~60seconds may be the best choice, but thebending deflection will achieve its extreme value of28.3mm during the quenchingprocess. Adjusting the quenching intensity of railhead can result in a well controlling ofthe deflection extremum of rails during the quenching process. Adjusting the quenchingintensity and the cooling time of rail flange can result in better controlling of thedeflection extremum during the quenching process and the final deflection afterquenching process. The less difference of the quenching intensity between railhead and rail flange, the smaller bending deformation. Anyhow, controlling the quenchingintensity of the rail flange can achieve a better controlling of the quenching process.Not only changes of the rail during the quenching process can be observed in realtime, but also the related data of the rail after quenching can be obtained by simulatingthe quenching process of rails, which can provide a powerful reference for theimprovement of rail quenching process.