Study On The Mechanism Of Tube End Thickening And Control Strategy In The Process Of Stretch Reduction

Seamless steel tube plays an important role in many industries of national economic development,and as the last line of hot rolling seamless steel tube deformation process,the tension reducing unit affects the dimensional accuracy and mechanical properties of the finished tube directly.Steel enterprises in all countries try to expand product specifications of steel tube,improve product quality and reduce production cost through this link.Therefore,research on the theory of basic technology in tension reducing process and finite element simulation for mechanism and control of tube end thickening were carried out to understand the deformation characteristics of the metal in tension reducing process thoroughly and master the influence rules of key technological parameters on tube end thickening,which have important theoretical significance and practical value to furtherly optimize the process parameters,reduce the loss of excision save energy and resources.The three-dimensional thermo-mechanical coupling finite element model of seamless steel tube in tension reducing process was established based on MSC.Marc,which was verified to be reliable and accurate by the actual production data,and the mechanism of tube end thickening in tension reducing process was furtherly analyzed.The change law of the tension force in the rolling and the cutting loss of head and tail end after rolling was studied while changing the initial temperature,the coefficient of friction,the reduction of the diameter and the coefficient of tension.The original crop end control CEC technology was studied and analyzed by the finite element method,and according to the working principle improvement of the existing three-level CEC control strategy and development of new tube end control technology was made to reach the international advanced level that could reduce the cutting loss of tube end from 20% to 50%.Based on the basic theory of the tension reduction process,the program of tension reducing process was developed to calculate and output the key technological parameters of the specified steel tube series based on VB software,which could also realize the accurate calculation of the process parameters of the new seamless steel tube varieties andfacilitate the seamless steel tube industry.