Numerical simulation and experiment study on the nuclear fuel spacer grid stamping of Inconel 718

Abstract Spacer grid (SG) made of Inconel 718 is a typical sheet metal part in nuclear energy industry, and SG is normally manufactured by multi-stage stamping process at room temperature with blanking followed by preforming, forming and trimming. The edge quality of the blanked sheet has crucial effect on the following forming steps. In order to reveal the forming mechanism and guide the stamping process and die design, mechanical properties of Inconel 718 were measured, and the threshold value of the ductile fracture criteria were calculated and validated by blanking process. The 3D multi-stage stamping process was simulated by using solid element and shell element with damage legacy data mapped from blanking stage to forming stage. The simulation results were validated by experiments.