Analysis of the wall thickness distortion in tube hydro-forging

The tensile deformation is the most common forming principle in sheet process, but there a new tube process—tube hydro-forging has been developed based on of compression deformation. In addition to instability problem, surface defect—thickness distortion—was found this paper, wall thickness distortion analyzed from point view mechanics and It revealed that low pressure hydroforming bending moment exists leads some small wrinkles straight wall. hydro-forging, would develop with increase compressive strain are two major effect factors. verified by experiments simulation. This study helps recognize phenomenon