Reseach On Three-roller Cold Rolling Process Of302Stainless Steel Tube

The cold rolling is a major method of tube cold manufacturing, especially for theforming of high-precision thin-walled tube, with the features of high capability ofreducing wall thickness, significant improvement of mechanical properties of thematerial, dimension accuracy and surface quality of tube product. With the rapiddevelopment of science and technology, thin-walled seamless stainless steel tubes havebeen widely used in the filed of aviation, electronics, chemistry, nuclear and otherindustries, while the quality requirement are increasing accordingly. Based on theforming characteristics of LD-type mill and finite element principles, three-roller coldrolling process for302stainless steel tube has been analyzed using nonlinear finiteelement simulation software MSC. Marc. The research results have a guidingsignificance to the actual production. The main research and results are summarized asfollowing:(1) Elastic-plastic finite element model of three-roller cold rolling for302stainlesssteel tube has been established through the suppositions and simplified processing of thedynamic contact boundary conditions, local coordinate controlling pure trundle andother critical technical issues by using finite element software MSC. Marc. The metalflow rules of deformation zone, the distributions of stress and strain during rollingprocess have been simulated and analyzed; meanwhile the occurrence of fracture hasbeen predicted in this thesis.(2) In this paper, the influences of technical parameters such as feed rate, rotationangle, friction coefficient and opening angle on rolling process have been analyzedprimarily. The effects of feed rate and opening angle on rolling force, as well as theeffect of rotation angle on inducing movement of tube deformation have been discussed.Through the comprehensive analysis the obtained reasonable parameters can provide abasis for the optimization of parameters of the simulation results.(3) The analysis of bamboo shaped defect on the surface of rolled tube indicates that the defect could be avoided effectively by optimization of the slide such asextension the length of diameter setting segment and reverse taper segment. Meanwhile,the cause of earring defect in the rolling process of tube has been analyzed andcompared with the simulation results. The simulation can effectively predict and avoidthe defect.(4) The parameters used in the simulation results have been verified throughexperiments. The numerical simulation results agree well with the experimental results,the tube product with good quality can be obtained in the experiment by using theoptimized process parameters in the simulation results. The research results can guidethe rolling manufacturing of stainless steel tube.