The research on SGMF process applied to metal pipe and sheet metal

Solid granular medium forming (SGMF) is a half-mold forming technology used for deep drawing and bulging processes on sheet metals, pipes and so on, where the rigid punch (or die) is replaced by solid granular medium. The process inherits the typical flexible manufacturing characteristics of traditional soft-mold forming process, and due to the inherent characteristics of solid particles in easy-to-seal, high temperature and pressure endurance as well as non-uniform pressure distribution, it provides a more advanced manufacturing technology for precise forming of high-strength, low plasticity, and less-deformable materials and the metal pipes, sheet metal precision stamping parts with high dimensional accuracy and surface quality. Therefore, it is a new soft-mold forming process, which is highly practical, versatile and low-cost. This paper summarizes a large number of tests and theoretical researches of SGMF process applied to pipe sheet, which is carried out by our group for many years. This process was applied successfully to manufacture bulging specimens of metal pipes with different-shaped cross section, such as the ripple-shaped, ladder-shaped, oval-shaped, etc. as well as typical drawing specimens of sheet metal, such as cylindrical, conical, parabolic, box-shaped etc. And the SGMF hot forming process was employed to trial-produce drawing parts of magnesium alloy sheet metal.