Numerical simulation of extrusion process and die structure optimization for a complex magnesium doorframe

The numerical simulation of extrusion process for complex hollow magnesium doorframe is carried out using HyperXtrude software. According to the simulation results, the extrusion die structure has been optimized in this article. The flow velocity, welding pressure, and temperature distributions, as well as the particle tracking function provided by HyperXtrude are all adopted to affirm the structural rationality of the optimal die design schemes. The simulation results show that there is a great difference in metal flow velocity at the cross-section of extrudates for the initial die structure which is not suitable for production. The introduction of baffle plates in the lower die has balanced the metal flow to be more even through increasing the metal flow resistance in the parts where the flowing velocity is faster than in other parts. In the meanwhile, the optimal die structure with proper baffle plates exhibits higher welding pressure and more uniform temperature distribution in the extrudates. This could further improve the welding quality and eliminate the thermal deformation of the final profiles. According to the optimum die design scheme, the real mold has been manufactured and extrusion experiment has been carried out. The actual products exhibit favorable surface quality without twist deformation and dimension mistakes. Moreover, there is visible grain refinement in the microstructure of the extrudates. It has been proved that the die structure design based on the numerical simulation on the extrusion process with HyperXtrude could provide guidelines for complex hollow magnesium profiles and accelerate the production efficiency.