The Study Of Sheet Metal Forming By Temperature Gradient Hydrodynamic Deep Drawing

Sheet metal forming is one of the important branches in the materials processing technology which has a wide range of applications on the various departments of the national economy, for example in the automotive, aviation, aerospace, ships, and household appliance and so on. It is a very important issue in the study process of sheet metal forming that how to use reasonable forming technology to improve the limit of sheet metal forming. Sheet metal warm hydrodynamic forming is one of the development trends of advanced sheet metal forming technology,having obvious effect on improving the limit of sheet metal forming;Research shows that sheet metal cold deep drawing based on hole expansion technology,also can improving the limit of sheet metal forming.In this paper,by using MARC finite element software,metal sheet advanced forming technology is carried out by simulation analysis.At first,combined sheet metal warm hydrodynamic forming with hole expansion technology,contrast with the ordinary warm hydroforming and warm hydrodynamic deep drawing based on hole expansion technology,discusses the effect on cup drawing process by hole expansion technology in sheet metal warm hydrodynamic forming;By researching on the process of sheet metal warm hydrodynamic deep drawing based on hole expansion technology,further discusses the effect on sheet metal drawing by forming gradient temperature field.Through the study found:Sheet metal warm hydrodynamic forming can combine effectively with hole expansion technology,hole expansion technology can further improving the limit of sheet metal forming in sheet metal warm hydrodynamic deep drawing;Sheet metal warm hydrodynamic forming based on hole expansion technology can further improving cup shaped parts’ limiting drawing ratio by forming gradient temperature field on the flange parts in the process of sheet metal heating.The main conclusions are as follows:(1)Under the condition of constant temperature 60 ℃, Ordinary warmhydrodynamic deep drawing and warm hydrodynamic deep drawing based on hole expansion technology are both reach their minimum value of cylindrical parts’ minimum thickness reduction ratio.In the ordinary warm hydrodynamic deep drawing,the maximum thickness reduction ratio is 26.3%;In the warm hydrodynamic deep drawing based on hole expansion technology, the maximum thickness reduction ratio is 16.2%.(2)Compared with the uniform heating drawing,temperature gradient heating drawing’s equivalent stress is less at the same node position,the maximum difference stress between the two is 37.20MPa;The maximum equivalent strain by temperature gradient heating drawing is smaller,the maximum difference strain between the two is0.077;Thickness reduction ratio by temperature gradient heating drawing is smaller,the parts’ thickness is more uniform.(3)When the die temperature is 50 ℃ and the overflow pressure is 25 MPa,the effect of temperature gradient heating drawing is the best,at this time,the thinnest point of the parts’ thickness is 0.868 mm, the thickness reduction ratio is 13.2%.(4)Hole expansion experiment illustrate, bigger hole expansion ratio can be achieved through temperature gradient hydrodynamic deep drawing,and the forming limit of hole expansion is higher.