Modeling of Nitrogen Cooling in the Extrusion of Aluminum Alloys

The extrusion process with liquid nitrogen cooled dies is widely adopted in industrial practice. Cooling channels are usually realized on the backer face in contact with the die and their design is mainly based on die maker experience. However, many parameters can be included in a die optimization, such as the number and the position of inlets/outlets, as well as the nitrogen channel position, shape, and dimensions. Trial-and-error approach is time and cost consuming, thus suggesting a great interest in numerical simulations to be carried out at the die design stage. In the present work, a model for the simulation of the nitrogen-cooled extrusion process is innovatively presented and validated. A simplified 1D model of the channel is integrated in a 3D Finite Element (FE) simulation of the extrusion process by means of COMSOL code. Two experimental campaigns specifically carried out to monitor the efficiency of nitrogen cooling in industrial plants have been simulated and results compared in terms of die and profile temperatures, as well as in terms of extrusion load, in cooled and uncooled conditions.