Design Of Roll Shape And Process Model Of Two-roller Straightening Machine For Tubes

In current years,the overall level of my country’s industrial development has reached the world’s first-class level,and the overall quality requirements for tube production are getting higher and higher.The quality of the tube is affected by various reasons that the process of production,processing and transportation,resulting in poor longitudinal straightness and cross-sectional roundness.In order to improve the final forming quality of the tube,it is necessary to rely on the inclined roll straightener to complete the finishing of the steel tube.Among them,the two-roll straightener with good finishing quality and high final precision has a core position in this field.At present,the design and processing technology of the domestic straightening equipment is relatively mature,but the research on the process control model is lagging behind the foreign advanced level.The actual production process relies heavily on the production experience of the manufacturing personnel,resulting in low production efficiency and unstable tube quality after straightening.In this paper,the method of theoretical analysis,numerical simulation and field verification is used to study the influence of the two-roller straightening theory and process parameters on the tube straightening effect.Based on the elastic-plastic theory,a high-precision tube straightening process model is established.The specific work of this paper is as follows:(1)To study the evolution law of each curvature in the process of one bending and recovery of tube straightening;take the residual curvature of the first bending as the original curvature of the next bending,and construct the curvature analysis model of the whole process of tube straightening.Combined with finite element simulation and field testing,the accuracy of the analytical model is verified,and the theoretical basis for the process parameter calculation model is laid.(2)Based on the energy method,the analytical calculation equations of the flattening force and the flattening amount are derived,and the flattening experiments and finite element simulations are carried out on tubes of different materials and specifications to obtain the setting method of the optimal flattening amount during the straightening process.Considering the influence of the flattening amount in the straightening process,the roll shape design method is optimized.(3)By constructing an analytical model of curvature of the whole process of tube straightening,the influence of process parameters such as guide plate spacing,inclination angle,and straightening speed on the tube straightening accuracy was systematically analyzed,and a calculation model of process parameters for tworoller straightening was constructed.(4)The whole process of tube straightening was simulated by finite element analysis software,and the straightness deviation in the longitudinal direction of the straightened tube,the roundness deviation in the cross section,the stress distribution at each stage in the whole straightening process and the whole process of straightening were analyzed.Data such as straight force changes over time are analyzed.The results show that the residual deflection of the tube after straightening is less than 1mm/m,and the roundness is 0.4%,which meets the accuracy requirements.