Failure Analysis Of Warm Extrusion Die For Magnetism Yoke With Finite Element Method And Structure Optimal Design

Warm extrusion die is endured high temperature, high pressure and local stress concentration during it is working, which makes the stress distribution inside the die not uniform, and makes the service life of the warm extrusion die very short. With the development of theories in the fields of heat conduction, elasticity and plasticity mechanics, optimal design and numerical calculation analysis technology, the traditional structure design and intensity check method has left many problems to be researched ulteriorly on the stress distribution inside the die, the accurate calculation and analysis can be made for the finite element model of warm extrusion die with the help of numerical calculation methods, resulting in the actual distribution of stress and strain inside the die. That supplies true and reliable dates used for the intensity calculation, thereby the distribution of stress and strain can be obviously improved, resulting in improvement of the carrying capacity and service life of the die to a large extent.In this paper, the magnetism yoke warm extrusion die is used as research object, the finite element of warm extrusion die is established, the thermal field, thermal stress field, coupled thermal-mechanical strain and coupled thermal-mechanical stress of warm extrusion die are analyzed, structure optimal design has achieved, resulting in some research results as follows.1. Base on the theories in the fields of heat conduction, elasticity and plasticity mechanics, mathematical models about temperature fields and thermal stress fields of warm extrusion dies are built up and boundary conditions under actual physical working environment are determined, the finite element method is used to calculate the temperature fields and thermal stress fields of the warm extrusion die, which discusses the main failure causes of warm extrusion die.2. The intensity calculation and analysis of magnetism yoke warm extrusion die is done accurately and therefore the values of Von Mises stress and strain inside the die as well as their distribution can be acquired during extrusion process.3. The research is done on the analysis and choice of major structure parameters of warm extrusion die, when the whole die cann't meet the requirement of intensity, the combined die is used to enhance intensity. the research has optimized the combined die under coupled thermal-mechanical condition by ANSYS Parametric Design Language and gets the best data of combined die inside and outside layers dimensions and surplus value.4. The optimal structure of warm extrusion die has achieved.The research results in the paper can be used to do accurate intensity analysis and structure optimal design of warm extrusion dies under actual physical conditions, which is helpful to get rid of the traditional "trial and error" design model of warm extrusion die and establishes the basis of enhancing the quality of die design and shorting design period.