Development Of High Strength Hydraulic Forming Pipe For X80 Automobile

Reducing the weight of components to achieve the goal of reducing energy consumption is the goal that people have been pursuing for a long time.Tube hydraulic forming technology is developed under this background.Compared with the traditional stamping,welding process,the hydraulic pipe forming automobile parts manufacturing technology has the advantages of light weight,good rigidity,high strength,hit resistibility,material saving,compact structure,processing technology saving and so on.This meets the special requirements of lightweight car.The deformation mechanism of Tube hydraulic forming is complex,and the related theory is not sufficient,and many key technologies have not yet been fully resolved.How to effectively improve the performance of tube hydraulic forming is the leading edge of the current international academic research.Grasping the technology of pipe fitting as soon as possible will provide strong support for the development of the automobile industry in China.In this paper,a large number of domestic and foreign literatures has been consulted,and the technology of tube hydraulic forming has been systematically expounded.After that,a series of experiments on tube hydraulic forming materials and processes were carried out.In this paper,the automobile used high strength hydraulic forming pipe is the research object.On the basis of the existing equipment in Ansteel company,the chemical compositions and rolling process of a 440 MPa hydraulic forming steel were designed,the effects of rolling processes on the microstructure and mechanical properties of the steel were analyzed,and the suitable chemical compositions and rolling process were determined.In addition,the hydraulic forming process of 440 MPa internal high pressure forming plate was studied,the existing problems were summarized and analyzed,and the results of laser welding cup convex test were analyzed,and the suitable laser welding process was finally determined.After that,the mechanical properties of the 440 MPa grade laser welded pipe were tested by the pipe mechanical properties testing system,including tensile strength,tube expanding rate and stress strain curve.Finally,the tube expansion performance was determined.After that,the hydraulic forming tests were conducted on the developed high strength hydraulic forming pipe byb the hydraulic forming testing machine and the typical hydraulic forming mold for automobile,the appropriate hydraulic forming process was determined,and the using performance of the steel pipe was analyzed.This work provides the experimental basis for the application of the newly developed 440 MPa hydraulic forming steel in automobile production.