Research On Hydro-mechanical Deep Drawing Without Draw Die Of Tailor-welded Blanks

Tailor-welded blank(TWB) with different thickness ratio plays an important role in the lightweighting technology of automobile industry.Problems, such as weld-line movement and thickness reduction of its formability,are always occurred in the application and production of TWBS during the conventional drawing process.And these problems result in the bad quality and performance of the TWB products.So,how to solve these problems is the key point in the application and development of the new skill.Meanwhile,with the development of the special drawing process technology,nowadays,hydro-mechanical deep drawing without draw die which is an advanced technology of sheet forming have been largely accepted by industries day by day.The simplified die is a expression of the economy of the hydro-mechanical deep drawing without draw die. Comparing with the conventional deep drawing,the hydro-mechanical deep drawing without draw die has many merits such as low cost,high degree of accuracy and can raise the drawing ratio of the parts.It is suitable for produce different parts,especially for complex productions in one process.This paper analyses the theory of hydro-mechanical deep drawing without draw die for Tailor-welded Blanks square box,Numerical simulation of which was performed based on Dynaform software.The main processing parameters of the study were discussed as follows.First,comparison of formability of Tailor-welded Blanks square box between hydro-mechanical deep drawing without draw die and conventional drawing process.Second,the effect of material parameters and punch profile radius on the formability;Third,the effect of pre-bulging press and working press on the formability,How to determine these parameters is the key of the study,which has a practical significance for operation instruction. The study show that:First,there are different welded-line movement trends on the different blank area during hydro-mechanical deep drawing without draw die for tailor-welded blanks square box which always has a diving point at the sidewall.Second,the pre-bulging time and the magnitude of the working press are proportional to weld-line movement at the bottom.The blank thickness reduction will be increased with the enhancement of working press.Third, compare Hydro-mechanical deep drawing without draw die with conventional drawing,the numerical simulation indicate that proper control of the process parameters will help to improve the formability,especially the weld-line movement and the thickness reduction at the bottom.Forth,the peripheral press which is load on the blank edge can help to decrease the blank thickness reduction and increase the formability during hydro-mechanical deep drawing without draw die for Tailor-welded Blanks square box.Fifth,proper control of the liquid pressure loading paths in the die cavity will help to improve the forming quality effectively and the relative height can be achieved 4.25 at one-step forming under the friction maintain effect of liquid pressure.The study has an important guiding significance for real production of the tailor-welded blanks,and proves a new operation for the study of the TWB. The study lays an important foundation for the succeeding multi-parameter experiment design and the study of the Hydro-mechanical deep drawing without draw die.