Structural Optimization Design And Simulation Of LG35 Periodic Two-roller Cold-rolling Tube Machine

Cold-rolling seamless steel tube has characters of fine grain size,accurate geometry dimension,high surface accuracy,and widely used in the industry of mechanical equipment,aeronautical manufacture,automobile and the others.Two-roller periodic tube mill is an important equipment for producing cold-rolling seamless steel tube,with the problem of low production efficiency and low products efficiency.So the requirements for higher-speed,continuous and automation have been developed.It worths to be noticed that high speed rolling mill would product a large imbalance inertia force on the rolling process,which easily makes vibration or noise and seriously affects working stability,even die life and products accuracy.Therefore,the research of the structural optimum design and simulation of two-roller periodic tube mill has a very big theoretical and engineering significance for mastering static and dynamic mechanics,achieving steady rolling and promoting the improvement of two-roll periodic tube mill and cold-rolling seamless steel tube manufacturing technology in our country.In this paper,LG35 two-roll periodic tube mill was taken as the research object and theoretical analysis and numerical simulation were used to optimize the structure to ensure the rolling operational stability and products reliability.The main research work is as follows:The processing principle of two-roll periodic tube mill and the movement of main motion system were firstly analyzed,After that,the motion simulation model was constructed by ADAMS and velocity,acceleration and displacement curves of each parts were gain from that,preparing a theoretical basis for the final optimization.A new synchronous dual-spindle and sector block balance mechanism,a balance shaft was added on the other side of high-speed shaft and the extra counterweights were added on the crankshaft and high-speed shafte in the meantime,was designed after the detail analysis for the current rolling mill commonly with the eccentric gear balance system.Besides,the equilibrium parameter optimization was developed by ADAMS and gained the optimal size of counterweigh with inner diameter of 105.31 mm,external diameter of 518.98 mm and height of 112.52 mm.The new optimal design reduced inertial force of the main motion system of rolling mill by 80.76%,which provided a possibility for the high-speed rolling mill.The research firstly carried on the static structural analysis and modal analysis for the frame of rolling mill and assured the optimal space and performance criterion.Additional.It also built a topological optimization model of frame based on the variable density method to optimize the structure.The density of elements was designed with the allowed stress and flexibility of total frame.The objectives was to reduce the volume fraction of body.The results showed that the frame mass reduced from 672.891 kg to 532.999 kg with a 20.79%optimal efficiency.Compared with traditional optimization method,Topological optimization method was more than effective and met the requirements for static structure and dynamic performance at the same time.Reassembled the optimized rolling mill and assessed the effect of rolling speed on product quality,LG35 cold-rolling tube mill model was built to simulate the periodic rolling process by Abaqus.The simulated results showed that the difference between simulation and theoretical calculation of maxium rolling force was 12.12%.And three indicators including the cross-section ovality,the deviation rates of inner diameter and wall thickstube products were calculated to quantitively represent the quality of rolling products.Furthermore,it could be considered that the rolling speed had hardly influence on roll force,forming quality and distribution of stress and strain when compared with the simulated results at high rolling speed.