Research On The Stamping Formability Of Tailor Rolled Blanks

Automobile lightweight is one of the main trends in the development of the automobile industry.As a new type of sheet,Tailor Rolled Blanks(TRB)can match the thickness of the parts according to the actual load of the parts,so the weight reduction of the body parts can be realized.However,the stamping formability of the TRB is not enough,which restricts its wide application.In this paper,the stamping formability of the TRB is studied,so as to provide references for the design of the TRB parts,the design of dies and the forming process.The main research work and main conclusions in this paper are as follows:(1)Experiment of stamping formability of TRB box parts were carried out under two kinds of drawing molds,it showed that the TRB box parts of the rounded mold had better stamping formability.It showed that when the holder force was 110 kN,lubricants were coated on the corner of the mold and on the sample,the same area with circular specimen could improve the formability of the TRB;After galvanized,the surface quality of the TRB was protected and corrosion,but the stamping formability were reduced.The best process parameters were Determined,when holder force was 110 kN,lubricants were coated on the corner of the mold and on the sample and the sample was rounded,the drawing depth of box parts was up to 21mm,main limit strain under tensile and compressive strain state of the box was 0.60,the limit strain was-0.12,limit main strain under bidirectional tensile strain state was 0.50,the limit strain was 0.10,box parts flowed evenly,center movement of the transition zone was small and it had a good stamping formability.(2)Experiment of U-shaped part bending springback of the TRB was carried out,its characteristic was that the springback of thick zone was greater than the thin zone;Changing the position of the lubricant,the lubricant was on the sample could appropriately could effectively decrease the springback angle;the punch speed had almost no effect on the springback;In the case of that the size of the sheet met the requirements,the use of smaller size sheet could effectively reduce the springback;Galvanization could also decrease the springback of U-shaped parts.When holder force was 10 kN,the lubricant was on the sample,specimen width was 30 mm,the springback angle of the U-shaped parts thick flange of the TRB was 6.00 degrees,the springback angle of the thick side wall was 2.00 degrees,the springback angle of the thin flange was 4.10 degrees,the springback angle of the thin side wall was 1.00 degrees,the springback of each region was minimized.(3)The stamping experiment of S-rail part of the TRB was carried out along the non-rolling direction and along the rolling direction.Along the non-rolling direction,the springback of the thin side flange of the TRB was larger than the springback of the thick side flange,the springback of the thick side wall of TRB was greater than the springback of the thin side wall.The longitudinal S-rail parts had different springback under different thickness,and the thickness was greater,the springback was smaller.Different holder forces were used to carry out the transverse and longitudinal drawing and bending tests.As the blankholder force increased,the springback decreased slowly and slowly,and the most suitable holder force was 50 kN.