| In order to meet the national development requirements for lightweight,energy-saving and emission reduction,lightweight replacement of automotive interior and exterior covers and body frame parts has become a major research direction in the field of automotive manufacturing technology.Aluminum alloy plate has many advantages such as light weight,high strength and good corrosion resistance.Now it has been widely used in the fields of automobile structural parts and covering parts to replace the original high-strength steel parts.But at present,the common deep drawing forming process of aluminum alloy has many shortcomings,which severely restricts its development demand for high forming quality.The fluid viscous and soft medium are used as the soft mold for sheet differential temperature and liquid-filled deep drawing.The process of simultaneously controlling the hydraulic medium and the mold temperature to achieve the excellent differential temperature and liquid-filled forming of the sheet is used to conduct the forming research of aluminum alloy parts.High requirements for drawing equipment and processes are relatively rare in the field of aluminum alloy sheet forming.In this paper,the 6061-T6 aluminum alloy biaxial stretching thermal bulging test,which is most compatible with the characteristics of the differential temperature and liquid-filled forming process and has a thick-to-pressing effect,is compared with the unidirectional hot stretching,and the stress in the temperature range is obtained by fitting-Strain curve and construct the constitutive relationship equation based on the new model of work hardening rate to apply to the forming research of flat-bottomed cylindrical parts.The finite element numerical simulation analysis was carried out on the door parts with complex profiles,so as to obtain the most excellent temperature difference temperature setting interval to accurately guide the difference temperature and liquid-filled deep drawing forming experiment.The research results show that: for the numerical simulation results of the differential temperature liquid-filled deep drawing of 6061-T6 aluminum alloy based on the new model of work hardening rate,the differential temperature of the flat-bottomed cylindrical part with a diameter of 50 mm is set as the flange area At200?-10?,the forming limit height of the punch reaches the best 60 mm,and the wall thickness reduction rate is 15%.In the forming experiment with the same parameters,the forming limit height reaches 67 mm,and the wall thickness reduction rate is 20%.It is covered in complex car doors.The temperature difference in the part is set at 200? in the flange area-10? in the punch,the strain is more uniform and the wall thickness reduction rate is at least 17%.The corresponding forming experiment wall thickness reduction rate reaches 20%,both are very good The simulation of the forming effect of the differential temperature liquid-filled deep drawing experiment;through the principle of differential temperature liquid-filled deep drawing,the liquid chamber,the mold temperature and the sheet temperature are controlled within a reasonable temperature difference range,so that the punch can be rounded.The strength of the material part is improved,the forming limit height is increased,the strain value and the sheet thickness reduction rate are reduced.Moreover,for the sheet material of the flange part that is insulated at a reasonable temperature level,the plastic flow of the sheet material during the deep drawing process is improved,which further improves the position quality of the constant wall thickness of the workpiece and the sheet material strain at the drawbead position The quality of its forming quality has been significantly improved. |
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