Research On Numerical Simulation Of Hot Rolling Billet For P110 Oil Well Steel Pipe

Oil casing pipe is mainly used for oil well and gas well sidewall support equipment.Because of its very poor working conditions,the tube body is subjected to various stress,such as bending,pressing and pulling,and the oil casing cannot be reused,which requires the casing with high comprehensive mechanical properties.To develop a reasonable production process is an important guarantee for product quality and performance.Therefore,the corresponding production of oil casing round bar hot rolling process proposed to develop a more reasonable hot rolling process requirements to improve the comprehensive mechanical properties of oil casing.The hot rolling process of the round bar belongs to the high temperature plastic deformation problem.During the rolling process,the rolling parameters are different.The temperature field,stress field,strain field and microstructure distribution of the round bar are also different and difficult to measure directly.The finite element numerical simulation of the hot rolling process of the round bar can shorten the product development cycle and reduce the rejection rate.In this paper,42 CrMo large-sized round steel for P110 oil casing is used as the object.Based on the analysis of the hot-rolling process of small and medium-sized round steel and combined with the finite element numerical simulation studies round steel hot rolling process have completed the following works:The six-pass rolling model of P110 round bar with diameter in the range of 133.7mm ~ 244.5mm was established,which included the selection of ?.?.Zelikov rolling temperature model,the Smirnov scale force model,Width formula and other mathematical models.Selected a reasonable hole to determine the rolling pass,the distribution of the amount of deformation,and calculating the cross-sectional area of rolling.The heat transfer equation in the hot rolling process was selected according to the hot rolling process of 42 CrMo round bar,including convective radiation heat transfer,contact heat conduction,metal plastic deformation heat and heat transfer.And the recrystallization model adopted by Prof.R.Kopp was selected to study the mechanism of grain refinement and 42 CrMo recrystallization in hot rolling process.This paper analyzed the causes of the wrinkles on the surface of the round bar,distribution of the stress,strain rate and metal flow velocity at the corners of the round bar with round steel rolling.The control variable method is used to analyze the fillet,rolling speed,lubrication and other technological parameters of the surface wrinkle to improve the effect of the law.Based on the dynamic recrystallization dynamics model,kinematic model and grain size function model of 42 CrMo,the finite element numerical simulation method is used to change the process parameters such as rolling temperature,rolling speed and pass pressure.