Research On Cylindrical Limit Drawing Coefficient Of DC04、DC05 Cold Rolled Deep-drawing Sheet

Due to the different anisotropy of steel sheet and other factors,the cold-rolled deep drawing sheet will exhibit uneven deformation on different directions in the deep drawing process,and a certain direction of sheet metal will reach drawing limit firstly,cracking phenomenon appears in that direction.The products unable to meet the requirements.When the selected drawing coefficient much bigger than the limit drawing coefficient,it will increase the drawing times,extend the manufacturing cycle,waste the raw materials and increase production costs.This paper explore the relationship between the anisotropy of cold-rolled deep drawing board and limit drawing coefficient,find a rapid way to determination the limit drawing coefficient.At the same time the determined limit drawing coefficient of cold-rolled deep drawing board by tested can supply the data of "Punching Manual",and extended to the actual product,provide the data basis for the actual production.This paper study on DC04 and DC05,two kinds representative cold-rolled deep drawing board.The main content introduce the theory of deep drawing,reference the based on plastic strain ratio limit drawing coefficient model,introduces the theory of anisotropic yield,compare plastic strain ratio and yield stress of the theoretical value and the actual value of the uniaxial tensile test,and shows the maximum deviation in all directions about the yield stress of DC04 and DC05 cold rolled sheet are no more than 2.6%,the maximum deviation in all directions about the plastic strain ratio of DC04 and DC05 cold rolled sheet are no more than3.5%,so the uniaxial tensile test is reliable.Take the plastic strain ratio and the strain hardening index obtained by uniaxial tensile test into the limit drawing coefficient model,calculate the limit drawing coefficient,and design the finite element simulation program of limit drawing coefficient based on the calculated value,can effectively save time simulation and computation.Apply DYNAFORM finite element software to simulate extreme drawing of cold rolled sheet,optimize calculated and simulated value of limit drawing coefficient,design the limit drawingcoefficient tests of cold rolled sheet.Design of the type Ⅰ and type Ⅱ drawing dies for limit drawing coefficient tests of DC04 and DC05,combined with the distribution of mechanical properties of materials in each angular direction,find the greater the yield stress the smaller plastic strain ratio of the direction,the material more prone to crack.Through four tests to determine the test values of limit drawing coefficient of DC04 and DC05 limit drawing coefficient,comparing the value calculated by limit drawing coefficient model and the value obtained by finite element simulation,find the deviation of analog value of finite element software be smaller,the minimum deviation is 2.6%.And the deviation of limit drawing coefficient model is larger,the maximum deviation is 4.4%.Therefore,the limit drawing coefficient can be quickly obtained by basing on plastic strain ratio limit drawing coefficient model in actual engineering applications and improve production efficiency.