Abstract: In a method of making finned tubes as components of air-cooled systems or condensers, a sheet metal strip of aluminum is first shaped into a waved finned structure with plural fins in parallel relationship and arched ends for connecting the fins, thereby defining crests on opposite ends of the finned structure. A fluxing agent of cesium-aluminum tetrafluoride is applied in lines onto the crests on at least one of the ends of the finned structure. The finned structure is then placed upon a broad side of a flat steel tube coated with a zinc/aluminum alloy. The finned structure and the flat tube are subsequently joined in a brazing furnace in the presence of an inert gas at a temperature between 370° C. and 470° C. to produce a unitary structure which is then allowed to cool down at room temperature.

Abstract: In a method of making finned tubes as components of air-cooled systems or condensers, a sheet metal strip of aluminum is first shaped into a waved finned structure with plural fins in parallel relationship and arched ends for connecting the fins, thereby defining crests on opposite ends of the finned structure. A fluxing agent of cesium-aluminum tetrafluoride is applied in lines onto the crests on at least one of the ends of the finned structure. The finned structure is then placed upon a broad side of a flat steel tube coated with a zinc/aluminum alloy. The finned structure and the flat tube are subsequently joined in a brazing furnace in the presence of an inert gas at a temperature between 370° C. and 470° C. to produce a unitary structure which is then allowed to cool down at room temperature.

Abstract: In a method for joining a steel tube with an aluminum rib, a zinc-aluminum alloy layer, having an aluminum content of 0.5% by wt. to 20% by wt., is applied to the surface of the steel tube or the aluminum rib, and then a fluxing agent in the form of cesium-aluminum tetrafluoride is applied between the steel tube and the aluminum rib at room temperature before or during the mechanical contact of the aluminum rib with the steel tube. The steel tube provided with the aluminum rib is then heated to a soldering temperature of between 370° C. and 470° C. and subjected to room temperature to cool down.

Abstract: In a method for joining a steel tube with an aluminum rib, a zinc-aluminum alloy layer, having an aluminum content of 0.5% by wt. to 20% by wt., is applied to the surface of the steel tube or the aluminum rib, and then a fluxing agent in the form of cesium-aluminum tetrafluoride is applied between the steel tube and the aluminum rib at room temperature before or during the mechanical contact of the aluminum rib with the steel tube. The steel tube provided with the aluminum rib is then heated to a soldering temperature of between 370° C. and 470° C. and subjected to room temperature to cool down.