Research On The Formability Of TG780 High Strength Steel Based On Different Layout Of Drawbead

TG780 high-strength steel,one of the third generation high-strength automobile steel,has excellent mechanical properties and formability,which meets people's increasing performance requirements for automobile safety and lightweight.Therefore,the application prospect of TG780 high-strength steel is very broad.Due to the short development time of TG780 highstrength steel,the research on TG780 high-strength steel is limited to the material structure control and microstructure The trip effect of metastable phase is less studied in the stamping process of TG780 high strength steel and the springback in the forming process.At present,the formability of TG780 high strength steel parts has been studied gradually.It is very important to explore the formability and service performance of TG780 high strength steel.In this paper,Dynaform software is used to test the U-shaped stamping of TG780 high-strength steel and DP780 high-strength steel,the mainstream automobile steel,under different layout of drawbead,to analyze the influence of layout of Drawbead on the forming and springback of the two kinds of plates;at the same time,in the aspect of test,the U-shaped stamping test of the two kinds of plates under the actual environment is carried out,and the forming knots of the two kinds of plates under different layout of drawbead are compared The effect of trip on the springback of TG780 high strength steel was analyzed.In this paper,the effects of different stamping speed,holding time and different pass forming on the springback of TG780 high strength steel are studied.Firstly,under the same drawing resistance,with the increase of the number of drawbead,the drawing effect of the two kinds of sheet metal is gradually improved.However,due to the deformation of the sheet metal by the double ribs for many times,the sheet metal flowing into the die is warped.When the drawbead is far away from the die side wall,the drawing effect can be improved,the side wall warpage can be reduced and the forming quality can be improved.Secondly,the results show that the springback of tg780 high strength steel is smaller than that of DP780 high-strength steel after stamping;there is a difference between tg780 highstrength steel test and simulation stamping springback,and the springback of double reinforcement is greater than that of single reinforcement;the rebound amount of extrapolated 40 mm single reinforcement group for two kinds of plates is the lowest under the six kinds of drawbead arrangement.Thirdly,when the stamping speed is in the range of 10 mm / min-30 mm / min,the springback presents a downward trend with the increase of speed;when the holding time is 60 s,the springback is the smallest;when different passes are formed,the single pre forming amount increases,and the springback has an increasing trend;with the increase of pre forming times,the springback has a downward trend.