METHOD FOR JOINING STEEL TUBES AND ALUMINUM RIBS Russian patent published in 2004 - IPC

FIELD: manufacture of ribbed tubes, for example for air cooled plants made of steel tubes with aluminum ribs. SUBSTANCE: method comprises steps of applying onto surfaces of steel tubes or aluminum ribs layer of aluminum-zinc alloy with content of aluminum in range 0.5 - 20 %; then before or during mechanical contact of aluminum ribs with steel tubes at temperature 20 C introducing between them flux containing tetrafluoride of cesium and aluminum; heating steel tubes provided with aluminum ribs in furnace until soldering temperature 370 - 470 C and finally cooling them at 20 C; according to other variant of invention at first applying onto surface of steel tubes or aluminum ribs layer of above mentioned alloy; then at 20 C applying flux such as tetrafluoride of cesium and aluminum at least on contact zones of aluminum ribs; providing contact of aluminum ribs with steel tubes heated until soldering temperature in range 370 - 470 C and realizing final cooling at 20 C. EFFECT: manufacture of ribbed tubes at comparatively small costs and rational consumption of materials. 2 cl