Viscous inner and outer pressure forming of 1Cr18Ni9Ti specimen with thin-wall curved surface

Workpieces with thin-wall curved surface are usually manufactured by forming parts decomposed and then parts formed assembled through welding, which spend multi-forming-step and too much cost. In this paper, an alternative method employing inner pressure and outer pressure with viscous media is proposed to form this kind of workpieces as a whole. By using numerical simulation and experimental methods, 1Cr18Ni9Ti specimens obtained by the viscous inner and outer pressure forming were analyzed, the diameter changing ratio of the specimen is 35%. The flowing rules of viscous media and sheet metal and the defects which occurred in forming process were investigated. Research results show that viscous inner and outer pressure forming of workpieces with thin-wall curved surface is feasible.