The aluminium tube characteristics are a kind of high-strength hard aluminium, which can be strengthened by heat treatment. It is moderately malleable under annealing, quenching and heat conditions. The spot welding is good. The aluminium tube has formed intercrystalline cracks when welding with gas welding and argon arc welding. tendency; Aluminium tubes have good cutting properties after quenching and cold hardening, and they are poor during annealing. The corrosion resistance is not high, and anodizing and painting methods are often used, or aluminium layers are added to the surface to improve corrosion resistance. It can also be used as a mold material. Aluminium tube advantages: first, welding technology advantages: suitable for industrial production of thin wall copper aluminium tube welding technology, known as the grade problem, is the air conditioner continuous control of aluminium copper key technology. The second is the advantage of service life: from the inside wall of aluminium tube, because the refrigerant does not contain water, the corrosion of the inner wall of the copper and aluminium joint pipe will not occur. Third, the advantages of energy conservation: the air conditioner indoor and outdoor machine connection lines, the lower the heat transfer efficiency, the more energy saving, or, the better the insulation effect, the more energy saving. Fourth, good bending performance, easy to install and move machine