In-line surface treatment for obtaining aluminium extrusions coated with a corrosion-resistant layer

摘要

Process for manufacturing aluminium alloy extruded profile parts which are resistant to the corrosion resulting from their contact with the air and humidity, comprising the following steps:a) providing a billet;b) extruding the billet through a die to create at least one profile having the desired shape and length and optionnally cooling or quenching the profile after the exit of the die;c) optionally stretching the profile;d) sawing the extruded profile to obtain profile parts at the desired length; characterised in thatduring step b) a corrosion-resistant layer is coated on the fresh metal surface exiting from the extrusion press by spraying a fluid solution near the exit of the die. The fluid solution is preferably a sol gel medium made from mixing a polysiloxane solution and an aqueous colloidal silica solution.;Profile parts coated with a corrosion resistant layer obtained by the said process.