Automotive heat exchanger aluminum with excellent brazing extrusion porous flat tube and its manufacturing method

摘要

PROBLEM TO BE SOLVED: To provide an aluminum extruded porous flattened tube for heat exchanger of a car excellent in a property to be brazed, in which flux composition or brazing composition can uniformly be pre-coated on the surface of the aluminum extruded porous flat tube in good transferability and adhesibility and the flux coating process can be omitted and brazing filler metal instead of a brazing sheet is not cladded at the time of assembling the heat exchanger. SOLUTION: At least one side of the flattened surface of the aluminum extruded porous flat tube is coated with the flux composition composed of a synthetic resin consisting essentially of polymer or copolymer of methacrylate ester and a brazing flux, or the brazing composition composed of the synthetic resin, brazing flux and a brazing filler metal. It is desirable to transfer a material adding the composition in organic solvent having 2-3 in the atomic ratio of carbon to oxygen molecular structure on the surface of the aluminum extruded porous flattened tube with roll.