Non-linear Finite Element Analysis Of Cold Drawing Internal Rifled Tubes Process

Rifled tubes, with spiral ribs on the internal surface, are a kind of tubes which have good thermodynamic properties. They are extensively used in large-scale power station. At present, the main method of producing internal rifled tubes is short mandrel drawing method. During the process of cold drawing internal rifled tubes with short mandrel, not only the diameter and wall thickness of the tubes change, but also produce spiral inside the tubes. So the metal flow in deformation zone is very complicated. It is necessary to master the rules of metal flow in the deformation of tubes in order to design the drawing die and technological parameter in reason. However, the analysis of cold drawing internal rifled tubes process belong to elsto-plastic and large deformation scope theoretically, and produce the material nonlinear question, moreover, can bring contact nonlinear question when the contact status changes. All these make it difficult to analyze theoretically. Until now, the theoretical study of the metal flow rules in the process of cold drawing internal rifled tubes is not reported in public.This paper achieves the FE simulation process of cold drawing internal rifled tubes with the non-linear FEA software MARC by FEM of large elastic-plastic deformation. The primary contents concerned are as follow:(1) Three dimension elasto-plastic FEM are employed to simulate the process of cold drawing internal rifled tubes.(2) Analyze the distribution of stress and strain in the deformation zone when cold drawing internal rifled tubes with three dimensional elasto-plastic FEM, and study the rules of metal flow.(3) Study the effects of relative position between mandrel and die on shaping up quality when cold drawing the internal rifled tubes with the method of theoretical analysis and FEM.(4) The effects of the reversed taper of mandrel on shaping up quality theoretically when cold drawing the internal rifled tubes are studied, including height of ribs, distortion of spiral shape, drawing force and external diameter of tubes. The preferable reversed taper of mandrel is presented after analysis.(5) Study the effects of friction coefficient and the number of screw thread on shaping up quality theoretically when cold drawing internal rifled tubes, and receive the corresponding rules.