How to solve the problem of welding line after aluminum pipe oxidation？

Most of the aluminum tubes on the market are produced by conventional combined die welding and extrusion process, which can not completely avoid the welding line, especially the dark line after oxidation. The extrusion process of short round rod, high temperature and slow speed shall be adopted in the extrusion production. In particular, the "three temperatures" shall be well controlled. The aluminum rod, extrusion cylinder and die shall be kept clean. The aging time and temperature shall be properly adjusted according to the thickness of the pipe wall and the size of each pipe diameter.

The aluminum tube extruder currently used includes an extrusion box and an air cylinder. The heated aluminum block is put into the extrusion box from the feed inlet. The air cylinder starts to work to make the extrusion beam push the aluminum block towards the extrusion die. The aluminum block under high temperature has good plasticity. When the temperature of the aluminum block decreases, the plasticity will also decrease. Under the action of a certain pressure and speed of the extrusion beam, The extrusion pad pushes the aluminum block to produce plastic flow and extrudes it from the extrusion die, so as to obtain the aluminum tube with the required section shape and size; In the extrusion process, the aluminum block is in a strong pressure state in the extrusion deformation zone, which can give full play to its plasticity and obtain large deformation. At the same time, the extrusion deformation can improve the microstructure and mechanical properties of metal materials, especially for the aluminum block with extrusion effect, the extruded products are in the longitudinal direction (extrusion direction) after quenching and aging The mechanical properties are much higher than those of similar products produced by other processing methods. Extrusion processing also has great flexibility. Products with different shapes, sizes and varieties can be produced on the same equipment only by replacing the extrusion die. The operation of replacing the extrusion die is simple, convenient, time-consuming and efficient. However, there are still great problems in the forming of some double-layer seamless aluminum tubes. Therefore, it is necessary to improve this situation.