| Due to the requirements to save the energy and to reduce the tail gas in automobile, making good use of forming technologies in the tailor-welded blanks (TWBs) which can reduce the part weights significantly becomes more and more important. It not only can reduce the weight of the parts, reduce the cost of the materials, but also can increase the entirety of the structure assemblage . And it can increase the shape precision. If the conventional technology is used in the forming process of the TWBs, some problems will exist, such as complex fabrication process, weld movement, thickness and uneven strain distribution which restrict the hydro-forming further application of TWBs. So, how to settle those problems becomes the key for the application and development of the TWBs technology.Meanwhile, as special technologies coming forth nowadays, Hydro-forming 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-forming. Comparing with the conventional deep drawing, the hydro-forming has many merits such as low cost, high degree of precision, good surface quality and can raise the drawing ratio of the parts. It is suitable for produce different parts, especially for complex productions in a single operation.So, against the upward failings of TWBs, the technology of hydro-forming is presented, and the typical TWBs are studied in numerical simulation way. The general rules for the process of the TWBs forming are found which provide a theory foundation for the die design and practical application.Based on the introductions of the application condition, study advance of the hydro-forming technology in and out nations, and the application of the numerical simulation in sheet forming process, this paper presents the significance and the prospect of applying TWBs hydro-forming. The conventional and the hydro-forming technologies of the box and the hemisphere are studied by using the Dynaform software. The study shows that the hydro-forming can improve the formability of the box TWBs effectively, and reduce the movement of the weld-line largely; The value of the weld-line movement reduces 94.7 percent; What's more, the technology of hydro-forming has many merits, little reduced tendency of blanks thickness, uniform distribution of the strain, good surface quality and so on; The obvious change of the hydro-forming of the hemisphere compared with the conventional forming is that the stress condition of the free part is improved obviously, though study of the effect of different processing parameters to the deep drawing, the result shows that wrinkles of different parts can be reduced obviously through some improvement, such as control blank binders with blocking, lubrication action and uniform counteraction force which the oil plays to the blanks. And the result also shows that the oil pressure is in inverse proportion to the weld- line movement and in direct proportion to the reduction of slab thickness.On the basis of adoption of the knowledge of the hydro-forming process and new devices invented recently abroad, the forming device for the experiment which is suit for the single action hydraulic stamping press is designed and manufactured. This device adopts oil press to control the binders which not only attain the blocking binders but also improve the flexibility ratio and the handling accuracy.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 TWBs. The study lays an important foundation for the succeeding multi-parameter experiment design and the study of the hydro-forming process, meanwhile, the designed experimental facility provides a hardware foundation for the post-experiment to proved the result of the numerical simulations. |
