Patent ID: 6193140
Filing Date: 2001-02-27
Classification: B23K,F28D,F28F

Abstract:
A process for the production of a heat exchanger core (6) based on aluminum wherein an aluminum-based extruded flattened heat exchanger tube (4) and an aluminum-based zinc-containing fin (5) are held in brazed relation to each other by the use of a brazing composition (7), characterized in that said heat exchanger tube is not pretreated with adhesion of zinc, and the process comprises applying on to the outer surface of said heat exchanger tube a brazing composition comprising fluorine type flux and a brazing material consisting essentially of silicon, preparing said fin formed of an aluminum-based zinc-containing material, and subsequently heating said heat exchanger tube and said fin at a given temperature, thereby bringing said heat exchanger tube and said fin into brazed relation to each other and also forming on the outer surface of said heat exchanger tube a mixed diffusion layer (8) of silicon and zinc, wherein the zinc contained in said fin combines with the silicon in said brazing composition during the brazing operation to form said mixed diffusion layer.