Numerical Simulation Of Rotating Bending Process Of Metal Tube

The hollow structures produced with metal tube has been widely used in a wide range of live and industrial applications due to high material utilization rate and light weight.However,metal tube manufactured by traditional methods often accompanied with grain coarsening,microstructure inhomogeneity and poor mechanical properties.Rotating bending process(RBP)as a novel severe plastic deformation method was proposed for microstructure and grain refinement of cylindrical tube.The variation of accumulated plastic strain of tube in RBP is unknown.In order to investigate the strain,RBP was numerically modeled by FE code which took H65 alloy as the material of the tube in this paper.The strain at different conditions obtained by FE method is beneficial for analysis of relationship between strain and grain size which can improve the efficiency to determine reasonable process parameters.Some main points of this paper are as follows:(1)On the basis of reading a large number of related articles,the development of the RBP was introduced,and the research on severe plastic deformation process,severe plastic deformation process of tube and the numerical simulation used in severe plastic deformation field was reviewed.(2)Tensile tests of H65 alloy at different strain rate and temperature conditions were proposed to obtain stress and strain curves.The curves were fitted with high accuracy by using Fields-Backofen model.(3)The material model was established by FORTRAN language writing the constitutive equation of H65 alloy to user subroutine,and the secondary development of the material library of the simulation platform was realized.(4)The process and principle of RBP were analyzed.The technological parameters that affect the deformation of tube were determined by the number of torsion cycles,bending degree and heating temperature.Based on the actual process,finite element models of RBP were established.(5)The results of numerical simulation were analyzed,and the relationships between technological parameters and the variation of plastic strain distribution were obtained in different stages of RBP.The variation of the mechanical properties and microstructure of the materials was explained reasonably by the law obtained from numerical calculation results,and the correctness of the law was verified.