Aluminum Profiles for Rail Transit

extrusion

Extrusion is a means of profile forming. Firstly, the die is designed and manufactured according to the profile product section, and the heated round cast rod is extruded from the die by extruder. The common grade 6063 alloy also uses an air-cooled quenching process and subsequent artificial aging process during extrusion to complete heat treatment strengthening. Different grades of heat treatable strengthening alloys have different heat treatment systems.

Coloring (here we mainly talk about the oxidation process)

Oxidation: the surface corrosion resistance of extruded aluminum alloy profile is not strong, so the surface treatment must be carried out through anodic oxidation to increase the corrosion resistance, wear resistance and appearance beauty of aluminum.

The main processes are:

(1) Surface pretreatment: clean the profile surface by chemical or physical methods to expose the pure matrix, so as to obtain a complete and dense artificial oxide film. Mirror or matte (Matt) surfaces can also be obtained by mechanical means.

(2) Anodizing: for the surface pretreated profile, under certain process conditions, the substrate surface will be anodized to form a dense, porous and strong adsorption Al2O3 film.

(3) Pore sealing: seal the pores of the porous oxide film generated after anodic oxidation, so as to enhance the anti pollution, anti-corrosion and wear resistance of the oxide film. The oxide film is colorless and transparent. By using the strong adsorption of the oxide film before sealing the hole, some metal salts are adsorbed and deposited in the film hole, which can make the appearance of the profile show many colors other than the natural color (silver white), such as black, bronze, golden yellow and stainless steel.

Characteristics and properties of aluminum profiles after various surface treatment processes