Study On Open-die Cold Extrusion Of Tubes By Numerical Simulation

Open-die cold extrusion technology is a high efficiency, low consumption of advanced production technology, it is usually applied to small and medium scale production of forgings. At present, this technology has been widespread attention at home and abroad. Now its simple structure, low forming power , simple procession, non-polluting and other advantage has been widely used in the automotive, motorcycle and household appliance industry. Numerical simulation technology as an integrated computational mechanics, computational mathematics, information science and other technology, integrated engineering and technical,it supports engineering and technical personnel to conduct innovative research and innovation, the important tool for the design and means.Based on the analysis of the pipe open-die cold extrusion forming process, established a theoretical calculation simplified model, used separately with the engineering theoretical calculation method: slab method and balanced work method, using these two methods has got the pressure calculation formula of the tube in the open-die cold extrusion process. After comparing the experimental data and theoretical data,theoretical calculations and experimental results are basically consistent.With the use of three-dimensional modeling software, pro/E geometric modeling, through the finite element software Deform-3D on the pipe open-die cold extrusion process of the numerical simulation studies. According to the results of analysis of finite element simulation of tube open-die cold extrusion process in the velocity field, stress field, strain field and pressure changes of stroke curve. The study of the metal yield strength, thickness to diameter ratio, friction coefficient, extrusion speed and die cone angle of several key process parameters on extrusion pressure, extrusion forming size (elongation, wall thickness increment, extrusion diameter size) and the die wall stress extruded parts forming defects (defects and open ends of pipe surface crack defects) were investigated. And respectively to reduce extrusion pressure, extrusion forming to improve the quality and reduce the die wall the stress range of the parameter optimization. According to a comprehensive analysis of simulation results we can see that there is a squeeze pressure of the smallest angle that is the best mold die half-cone angle, we can see select selected phosphorus saponification lubrication and plastic good condition and well-annealed metal blank in order to reduce the occurrence of extrusion defects and to improve the die life have an important role.