Microstructure, Thermophysical Properties and Numerical Simulation of Gradient Hot Stamping Die Inserts by WAAM and 3D Grafting Printing

A novel manufacturing strategy for hot stamping die inserts is proposed in this study. A three-layer die consisting of a quenched and tempered 45 steel substrate, ANCO-X intermediate layer and Fe-based surface layer was fabricated via 3D grafting printing and wire arc additive manufacturing (WAAM). The microstructure, high-temperature mechanical properties and thermophysical parameters of the prepared specimens were experimentally investigated. ANCO-X and an Fe-based alloy were selected as the intermediate layer and surface layer of the die, respectively. Furthermore, the simulation results indicated that the temperature field of the novel die reaches dynamic thermal equilibrium after six stamping cycles; the maximum Mises equivalent stress of the novel die in critical regions was always less than the yield strength of the corresponding materials, which demonstrated that the dies manufactured by hybrid additive manufacturing could satisfy the service strength requirements. Finally, the novel die insert embedded with conformal cooling channels (CCCs) was successfully fabricated by integrating 3D grafting printing and WAAM, which verifies the feasibility of the proposed manufacturing route.