| Aluminum alloy has many advantages,such as low density,high specific strength,good corrosion resistance,and low cost.Therefore,aluminum alloy is applied more and more widely in the fields of automobile,aerospace and other areas.It is studied that the formability of aluminum alloy on heat condition is better than at room temperature and it has low energy consumption and the process is easy to control,which has gained more and more attention as an important processing method in sheet stamping field.The hot forming process of aluminum alloy plate is obtained mainly through heating treatment to reach the desired temperature,and then treated by strengthening after the stamping process.At present,aluminum alloy plate on the mechanical performance and rheological behavior and other technological parameters in hot forming process is less researched.So the forming properties and technological parameters of aluminum alloy are studied by hot forming process.The main research contents and achievements are as follows:1.Tensile tests on aluminum alloy plate were performed at temperatures of 200℃、250℃、300℃ and 350℃ with strain rates of 0.01s-1、0.1s-1、1s-1 respectively.The effects of forming temperature within the top limit and strain rate on aluminum alloy plate were studied which showed that the higher temperature of the forming process is,the lower deformation resistance,the smaller tensile strength and better plastic deformation of the material.The bigger sheet forming deformation rate,the higher tensile strength of the aluminum alloy.2.By fitting the test data of 6016 aluminum alloy plate in hot forming conditions and the key parameters of sheet metal forming performance were determined to establish the constitutive equation of the aluminum alloy,the constitutive equation was tested and verified at last.3.The effects of temperature,BHF,friction coefficient and stamping speed on the forming performance of the cylinder parts were studied by the self-made deep drawing test of cylinder parts and simulation.The results show that the higher of the temperature,the better forming performance of the aluminum alloy and more easily formed of the cylindrical parts within a certain temperature range.With the increase of BHF,the maximum thinning rate of the hot stamping decreases.When the BHF is too large,it breaks at the fillet of the punch.Studied the affects of friction coefficient on the cylindrical parts under the conditionof uniform lubrication and uneven lubrication.The friction coefficient has significant effect on the minimum thickness,obtained the influence law of the forming process.The stamping speed has significantly affect the uniform cylinder thickness,which reveals the influence of uniform thickness.4.The drawing direction,shape of addendum,blank-holder surface and the design of drawbead and other key elements are determined through simulation on the roof supporting parts.Studied the effect of temperature and blank holder force and other parameters on the stamping parts.Finally researched the effect of whether the drawbead is set or not on sheet metal formability.5.In order to study the springback law of aluminum alloy sheet in forming process.The influence of forming temperature,blank holder force and friction coefficient effect on the springback is studied by means of orthogonal experiment combined with numerical simulation.The results showed that the heating temperature has the most impact,followed by blank holder force,the friction coefficient impact is minimal. |
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