Extrusion of Light and Ultralight Alloys with Liquid Nitrogen Conformal Cooled Dies: Process Analysis and Simulation

The die cooling by means of liquid nitrogen is a widely adopted industrial practice used to increase theproduction rate in the hot extrusion process of light alloys. The development of a reliable numerical modelable to simulate the cooling channel efficiency has become of primary interest for the extrusion sector inorder to avoid ineffective die cooling and time-consuming trials and errors. In this work, H13 die insertswith a helicoidally conformal channel were designed and printed by means of the SLM additive technology.Billets of AA6063 aluminum and ZM21 magnesium alloys were extruded at different process speeds undermonitored conditions to verify the insert resistance and the cooling effectiveness. A 3D finite element modelof the extrusion process coupled with a 1D model of the cooling channel was generated within the COMSOLsimulation environment. The experimental outputs were also used to validate the numerical predictions ofthe developed simulations. The FEM results showed a good matching with the loads and temperaturesobtained in the experimental trials. Moreover, the endurance of the AM tool validated the prediction of thestress field, thus proving the reliability of the numerical model for the application in the extrusion of lightalloys sector.