Study on extrusion of aluminum microchannel flat tube

Micro-channel tube with submillimeter-diameter channels is a kind of newly developed heat transferring tube. As the micro-channel tube has many welding points and works under high pressure condition, welding strength is one of the key issues for its extrusion process. This paper presented a new study on evaluation of the seam welding strength formed in the extrusion process. Firstly, FE simulation is carried out for the status of the billet in the welding chamber during the extrusion process. Then, thermo mechanical experiment is done to study the relationship between the welding strength and key factors. The welding process is characterized as the void evolution on the welding interface, which consists of void generation, void cohesion and void closure. Combining the relationship with the numerical results, welding strength of the micro-channel tube can be evaluated. The extrusion die is developed and the microchannel tube is successfully extruded. The study is helpful for the optimization the extrusion process and improvement of the seam weld quality.