Numerical Simulation On The Deep-drawing Processing Of Hemispherical AZ31 Magnesium Alloy

As the lightest metallic structural materials,magnesium alloys are considered as the environment-friendly engineering material with the greatest prospects for development in the 21 st century.Especially,wrought magnesium alloy sheets h ave broad application prospects due to their excellent combined properties.In recent years,rapid development has been achieved aiming at magnesium alloys.However,few research concerns the drawing process and thus their application development is restricted to a great extent.In this paper,DYNAFORM numerical simulation software is used to study the deep-drawing technology of hemispherical AZ31 magnesium alloy.Effects of drawing parameters such as temperature,speed,BHF,friction coefficient and mold parameter on the deep-drawing process are also investigated.It is expected to provide guidance for the mold and technology design.Firstly,effects of temperature,deep-drawing speed,BHF(blank holder force),lubricating condition,and the cavity die circular-arc respectively on the deep-drawing process are studied in a controlling variation method.Also the forming result and thickness variation under different deep-drawing conditions are investigated.The results show that the drawing ability increases firstly and then decreases with increasing the temperature.The optimized deep-drawing temperature of AZ31 magnesium is about 200 ?.Using a virtual deep-drawing speed of 3000 mm/s,the deep drawing ability can be fully realized and the simulation efficienc y can be ensured.Either too larger or lower BHF is not conducive to the formation.The right cavity die and friction coefficient of the blank holder can inhibit inner wrinkle,while the right friction coefficient of force plug can reduce the thinning rate.And there exists a strong correlation between cavity die circular-arc and BHF,and the proper collocation of both of which is conducive to formation.Secondly,effects of BHF,friction coefficient of force plug and cavity die circular-arc on the thinning and thickening rate are analyzed in an orthogonal experiment.The results show that BHF has the strongest effect while the cavities die circular-arc the least both on thinning and thickening rate.Thirdly,a novel technology of Mg/Steel composite plates deep-drawing is proposed to improve the deep-drawing ability of magnesium alloys.Effects of stacking order and thickness ration on the deep-drawing ability are investigated.It is found that the novel technology improves the deep-drawing ability and reduces the thinning rate remarkably.The stacking order and thickness ration have prominent effects on the deep-drawing process.The upper plate wrinkles easily while the lower plate has a bigger thinning rate.As the magnesium plate becomes thicker,it doesn't wrinkle easily and the thickness becomes even.