| Deformation of steel plate along the thickness direction was non-uniform during the traditional rolling,which was a small compression ratio in center.The deformation cannot penetrate from the face layer to center made the defects unbinding.Accordingly,a new type of rolling technology is proposed as temperature gradient rolling.TGR is a process that cooling while rolling and the center could not cool down,so that a non-uniform temperature distribution was forming that low temperature on surface and high temperature in center.With this rolling method,the harden layer on surface could prompt deformation penetrated from surface to center,which could remove the defects in the center of plate to enhance uniformity of the deformation along thickness direction.However,an obvious problem in the temperature gradient rolling was that the plastic deformation ability of the different thickness layers is different due to the gradient distribution of temperature field along thickness direction,that results in the problem of the bad plate shape.Warping phenomenon in plate and strip rolling is one of the important technique problem in rolling field which haven't be solved well.In this paper,the deformation uniformity and permeability in the process of temperature gradient rolling are studied.The effect of traditional hot rolling and temperature gradient rolling on the microstructure and properties of steel is tested by relevant experimental equipment.And the Deform-3D will be used to simulate and study the deformation uniformity and the head warping behavior during the temperature gradient rolling,that provides an effective reference for actual production and technique optimization.The major research results were as follows:(1)In the laboratory conditions,the 0750 hot-rolled mill and instant cooling device with 3D print technology were used to carry out the traditional hot rolling and temperature gradient rolling experiments.The experimental results show that the microstructure and mechanical properties of steel are improved by the temperature gradient rolling process,which increases the permeability of deformation,improves the strength and toughness of the steel,and is favorable for full excavation material performance potential,simplifies the rolling process,shortens the production time and improves the rolling efficiency.(2)The temperature gradient rolling of high temperature steel plate under different thickness was simulated that based on the Deform-3D finite element software.The simulation results show that the temperature gradient along the thickness direction of plate decreases gradually with the heat conduction at different positions of the same thickness plate and the difference of the plastic deformation capacity of different thickness layers.The warping height of the steel plate is also gradually reduced,so the plate shape tends to be good gradually.(3)The temperature gradient rolling of high temperature steel plate in the same reverse time was simulated based on the Deform-3D finite element software.The simulation results show that the difference of temperature gradient is bigger when the thickness is bigger in same reverse time,and the thickness of the plate becomes the main factor to influence the warping height.The thickness range of 30mm is the most sensitive to the plate warping.While the steel plate warping is not obvious with the thick steel plate.(4)The results of temperature gradient rolling experiments on 0450 rolling mill were carried out to verify the simulation results under laboratory conditions.The results show that the surface temperature decreases with the increase of cooling time,and the temperature gradient also increases,so the warping height increases obviously.(5)The temperature gradient compensation rolling experiments were carried out under laboratory conditions.Through the precise control of temperature and cooling path,the poor shape of plate can be corrected well with the application of the reverse-temperature gradient. |
PDF Full Text Request