Soldering lug for CAB soldering without soldering flux

Abstract

The invention discloses a soldering lug for CAB soldering without soldering flux. The soldering lug comprises a brazing filler metal layer and skin layers wrapping the two sides of the brazing filler metal layer. The soldering lug is characterized in that the brazing filler metal layer comprises 5%-15% of silicon, 0.01%-1% of magnesium and 0.05%-0.15% of bismuth, and each skin layer comprises 3%-12% of Si and less than 0.10% of magnesium. According to the soldering lug, no core layer is arranged, the soldering lug is fully molten during soldering and flows into a region to be soldered, a soldering seam is formed and attractive in appearance, the quality of products is good, no residue exists, soldering flux pollution is avoided, and the soldering efficiency of the products is high; due to the fact that a three-layer structure is adopted, the very thin soldering lug can be made, the soldering lug is applied to complex components and occasions where the soldering portions are very narrow, such as CAB soldering without the soldering flux of aluminum alloys of part extrusion, part machining and the like, and therefore the soldering lug is extremely wide in application range; and meanwhile the soldering lug is extremely simple in structure, the manufacturing process is simple, the consumption of materials can be saved, and the manufacturing cost is lowered.

Description

technical field [0001] The invention relates to a brazing sheet used on an aluminum alloy heat exchanger, in particular to a brazing sheet used for flux-free brazing in a non-oxidizing atmosphere brazing furnace, in particular to a CAB flux-free brazing sheet Brazed lugs. Background technique [0002] In any of the following descriptions of alloy compositions or preferred alloy compositions, references to percentages are by weight unless otherwise specified. [0003] There are two main furnace brazing methods for aluminum alloy heat exchangers, one is vacuum brazing, and the other is CAB brazing (controlled atmosphere brazing). [0004] Vacuum brazing uses a vacuum system to evacuate the brazing furnace to ensure that the vacuum of the furnace is higher than 3×10 - 3 Pa, during brazing, the volatilization of the Mg element in the brazing composite plate under high temperature and high vacuum conditions is used to remove the oxide film on the surface of the aluminum alloy,...

AI Technical Summary

Problems solved by technology

Since the brazing part is very narrow, and the thickness of the above-mentioned 5-layer brazing composite plate is usually more than 300μm, it cannot be applied in these places where the space is limited

[0009] In addition, the 4045 aluminum alloy brazing sheet and the 4104 aluminum alloy brazing sheet that have been produced industrially are used for controlled atmosphere protection Nocolok brazing and vacuum brazing respectively, but these two brazing sheets cannot be used for CAB without flux Brazing

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