Simulation And Experimental Study Of 2-dimensional Electro-hydraulic Chattering On Cold Extrusion Process

As a traditional plastic forming method,cold extrusion has been widely used in automobile manufacturing,daily hardware and other field's duo to its advantages such as high quality,high yield,and low energy consumption and so on.However,the disadvantages of cold extrusion such as large deformation resistance,metal flow difficulty,low die life and etc.limit its further development.To solve this problem,an axial electro-hydraulic chattering assisted cold extrusion process was proposed by our group and the results showed that the addition of axial chattering excitation could reduce the extrusion load,but it was not significant and the improvement of metal flow was not obvious.On the basis of previous research,a 2-dimensional electro-hydraulic chattering assisted cold extrusion process was proposed in this paper.A kind of 2D electro-chattering assisted cold extrusion experiment platform for cup parts was designed and built.Finite element analysis and experimental study for the influence of 2-dimensional electro-hydraulic chattering on the extrusion load,metal flow and surface quality was carried out.In this paper,the main research works and achievements are as follows:(1)A preliminary study on the "surface effect" and "volume effect" of the 2DCE process for a kind of cup parts was studied and reduction mechanism was proposed.(2)Deform-3D was used to build the finite element model for chattering assisted extrusion process and cold extrusion processes without and with all kinds of chattering were studied.The results showed that: the maximum extrusion load for the 2DCE process was decreased by about 12.38%,was superior to the ACE process for about 7.4% and the RCE process for about 2.75%.The metal flow was further optimized,and the stress field distribution was more uniform for the 2DCE process.(3)A kind of 2D electro-chattering assisted cold extrusion experiment platform was designed and built and the various parts of the composition and working principle were introduced.(4)The forming process of electro-hydraulic chattering assisted cold extrusion was proposed and experimental study for cold extrusion processes with all kinds of chattering was carried out.The experimental results showed that the simulation results were in good agreement with the experimental results,and the load reduction effect for 2DCE was significantly better than that of the single axial electro-hydraulic chattering.The flow line and surface morphology of the metal forming parts under all kinds of chattering were observed and analyzed.The results showed that the flow of metal in the corner was smoother,the metal flowing power source was increased,and the metal surface quality was improved with 2D electro-hydraulic chattering.The results of the study above indicated that the effects of reducing the load,improvement of metal flow and surface quality for the 2DCE process were all better than that of single axial electro-hydraulic chattering or no chattering.This technology can provide an effective way for the high quality forming of the traditional hard forming parts in the press with low tonnage.