Deformation behavior of haynes230 superalloy during backward flow forming

Flow forming manufacturing technique has a unique advantage in producing thin-walled cylindrical parts, witnessing a growing demand in defense, aerospace and other fields. However, some of mechanisms of flow forming have not been deeply understood yet. Aiming at easily appearing problems of the crack and expanding, a finite element model with implicit code has been developed to simulate backward flow forming process for production of thin-walled superalloy tubular parts. The material displacement and stressstrain field distribution were obtained, impact of material displacement to dimensional accuracy and residual stress of spun part was analyzed; distribution of strain vector along thickness of spun part and its influence on the occurrence of fracture was analyzed. The results indicate that inhomogeneous distribution of material displacement in thickness brings about residual tensile stress in outer layer and residual compressive stress in inner layer of spun part; plastic deformation occurs mainly in the outer layer; shear plastic strain on the outer surface is much larger than the inner, which may lead to fracture on the outer surface. Above research can play an active role in understanding the mechanism of backward flow forming and deepening the understanding of fracture and the optimization of the process parameters.