Optimization of Hot Backward Extrusion Process Parameters for Seamless Tube of Mg-8Gd-3Y Alloy by Finite Element Simulation

Based on the thermal compression stress–strain curves and the three-dimensional processing maps of the Mg-8Gd-3Y alloy in our previous published work, the simulations of the backward extrusion of seamless tube were conducted under different formable parameters. The effective strain deviation and power dissipation efficiency were used to measure the strain uniformity and formability of the material, respectively. The results show that the largest and most uniform strain, and the best formability can be achieved under the process parameters of 430 °C and 1 mm/s. Finally, the backward extrusion experiments of seamless tube were carried out under the optimal process parameters. The seamless tubes with an outer diameter of 106 mm, an inner diameter of 76 mm and a height of 3700 mm were made by backward extrusion. The tubes have relatively uniform microstructures and mechanical properties, and the difference of tensile strength of each position is less than 10 MPa.