Theoretical Research And Numerical Simulation On Rail Beam Blank Rolling

Railway transport with its advantages of high speed, high efficiency, safety, and hugecapacity becomes an important transportation means in our country，in the foreseeablefuture railway is still the main means for land transport. Rail act as a fundamentalcomponent after more than one century’s development, it’s related technology is still in theascendant, especially with the development of high-speed railway, heavy haul railway andcity express railway, the demanding requirements for rail is put forward, thus the need fortheory related to rail, especially the in-depth research of the rolling theory becomes moreurgent. Currently the continuous casting technology of net-shape beam blank for universalrolling is still immature, the rolled piece rolling into universal mill still need cogging, thatis, rectangular blank rolled into rail beam blank after certain passes, finally the railuniversal rolling is completed. Currently, rolling theory related to rail beam blank mainlyrefer to pass rolling especially I-beam rolling and field experience, in-depth research isless done.In this paper, variational method of rigid-plastic finite element theory is applied to thefurther research for the rolling process of rail beam blank, deformation mechanism ofrolling process for rail beam blank is thoroughly analyzed, thus useful reference for furtherimprovement of rail rolling quality is provided.Firstly, theory related to the rail beam blank rolling is discussed, deformationmechanism that rolled piece rolled into rail beam blank pass is thoroughly analyzed. Therolling process of rail beam blank is typical two-roller pass rolling and pass rolling is verydifferent from ordinary flat-roller rolling, many factors must be taken into consideration,such as outside-area, the reduction unevenly distributed along the width’ direction,non-simultaneity contact between the rolled piece and roller, sidewall and shape of thepass, velocity difference along radius in roller and open-closed side of pass.Secondly, theoretical research on the process of rail beam blank rolling is done byusing variational method of rigid-plastic finite element theory. The kinematic permissiblevelocity field in different passes is set according to deformation characteristics that rolledpieces rolled in different pass and certain assumptions that using in kinematic permissiblevelocity field setting by variational method, the deformed zone is thoroughly analyzed, so significant parameter is determined such as cross-section height in the pass deformed zoneand roller radius, thus the rolling power is determined, including plastic deformationpower, fiction power by using coordinate curved surface integral and shear power thatexisted in velocity discontinuous surface.Finally, the rolling process of rail beam blank is simulated by using rigid-plastic finiteelement analysis software DEFORM, various kinds of parameter in different pass isobtained, the deformation law of metal plastic flow velocity，stress and strain in rolledpieces is thoroughly analyzed，uneven deformation of rolled pieces in typical pass isthoroughly analyzed, finally rolling torque in theoretical calculation, numerical simulationand field data is comparatively analyzed, so the setting of kinematic permissible velocityfield and torque calculation is verified, thus deformation law in the pass rolling is verified.