Comprehensive Evaluation Of Strength And Stiffness About Rolling Mill Main Drive System Of Mandrel Mill Group

In the some seamless plant,there are five rolling mill in the MIN—MPM mandrel mill group.The original design is:the motor horsepower of the first rolling mill is 1700KW;the motor horsepower of the second rolling mill is 2000KW.The two motor are able to meet the need of rolling when roll general standard tube.But, during the course of rolling thin-wall tube,the brush of the 1# and 2# principal electric machine which act as the part of the MIN—MPM mandrel mill group often appear the phenomena of melting loss on account of the capacity of electric machine isn't sufficient. This phenomena is very difficult for electric machine maintenance. Therefore,this plant carry out an improvement of electric machine capacity-expansion on the 1# and 2# principal electric machine of the rolling mill.The improved project as follows:the project is attained by use of the two primary electric machine and a new electric machine whose motor horsepower is 1700KW.the horsepower of the 1# principal electric machine is amplified by 2000KW.The 2# principal electric machine which is 2000KW instead by two 1700kw electric machine.This two 1700kw electric machine is used in series.This improvement basically solve the problem on line. Obviously ,the power of the second rolling mill of this plant enable provides more capability on account of electromotor's power improvement.On the other hand, the strength of the main drive system system and the rolling mill housing can have become a concerning question of this plant in company with the improvement of rolling power.This article is produced on such background.This article apply the theory of vibration and the technique of finite element analysis to make a intensive study on the tube rolling mill system and the strength of the rolling mill housing in order to get the maximize rolling force which the rolling mill system can receive.First,we established torsional vibration system dynamics model by the theory of vibration, and figure out moment of inertia and torsional stiffness by Solidworks software and traditional computing formula.Secondly,we simplify the rolling mill system for four quality torsional vibration system.Base on this four quality torsional vibration system we figure out the free running frequency and principal mode of the four quality torsional vibration system.In this article, modal superposition method is applied to figure out torque response.We apply Runge-Kutta to solve second-order differential system according to initial condition and load-up condition .Finally,the torque response and torque amplification coefficient of different shaft can be obtained. Afterward,the author comprehensive analysis the strength of the miscellaneous part which exsit in the transmission system according to the dimension and material of it.On the basis of the torque amplification coefficient and the result of analysis , the author found that the shaft between the roller and redactor is weak link of the transmission system. Owing to the roll housing cannot replaceability,therefore we should convert the torque which weak link of system can bearing for rolling force so that we can get the strength and stiffness instance of the roll housing at that time. According to the characteristic of deformation range with axle rolling,we should change the maximize dynamic roll torque which is obtained by roll torque multiply torque amplification coefficient into rolling force.Finially,we apply ANSYS 8.0 to figure out the strength and stiffness of the roll housing with the rolling force act on the rolling housing .At last, the author draw a conclusion that the rolling mill housing have margin safety factor when it take this load.According to the result of static and dynamic analysis,the author made comprehen-sive evaluation about the improved transmission system.The final evaluation result is: the improvement of electric machine capacity-expansion.have solve the problem which trou-bled the yielding,but the effect of step up rolling force is not distinctness.The capacity of electric machine is limited by transmission system Therefore,the weak link of transmission system require improve if we want to step up rolling force.