Technology and Equipment of the Pulsating Hydroforming Technology

Forming theories, processes properties, mechanism and industrial application of the novel pulsating hydroforming are introduced. The formability can be improved by pulsating hydroforming in which the effect on formability should be understood from two different aspects of process parameters and material properties. The tube is uniformly expanded by repeating the appearance and disappearance of small wrinkling and the contact friction force between the tube and die is reduced under the pulsating load path condition. On the other hand, the enhanced transformation induced plasticity(TRIP) effect can improve the formability of austenitic stainless steel by pulsating load. Pulsating hydroforming equipment has been independently designed and developed which is composed of axial feed control system, liquid filling system and high pressure creation and pulsating load control system. The research results have both important theoretical significance and practical potential in application of pulsating hydroforming technology in the fields of automobile, aeronautical and astronautical industry.