Research on AZ31 magnesium alloy tee joint tube with lateral hole by hot extrusion forming with sand mandrel limited by stainless steel gasket

Abstract

As one of the lightest metals in the world, magnesium alloy can be used to reduce weight and save energy. Magnesium alloy tubes with different shapes can also further direct the transportation of fluid in this light weight. But the tee joint tube is difficult formed because of the complex shapes. In this paper, magnesium alloy tube is applied to form tee joint tube with sand mandrel. During the deformation, the magnesium alloy tube is driven by the sand mandrel pressed by the push. Different from traditional extruding with full tubes without hole on the sidewall, some tube with holes on the sidewalls are also used in the extrusion. All the key parameters such as extrusion depth, temperature, tube length, hole size, and hole location are discussed in both simulations and experiments. After the extrusion results are obtained, the microhardness and microstructures are observed to explain the promotion of the mechanical properties. Based on the results received from both simulations and experiments, deeper extrusion depth, higher temperature, shorter length of tube, larger size of the hole, and the higher location of the hole influence positively on forming results. No matter there are holes or not on the sidewalls, the errors between the results in simulation and experiment are small. Also the simulation and experiment results can be used to investigate the shape of tee joint tubes. The surface quality can be also measured to prove the surfaces in extrusion with sand mandrel acceptable. A novel strategy to sand mandrel extrusion of magnesium alloy tee joint tube by tube with holes on sidewall is provided.