Self-contained soldering flux type solder ring and preparation method thereof

Abstract

The invention relates to a self-contained soldering flux type solder ring and a preparation method thereof. The self-contained soldering flux type solder ring comprises an inner core of a solder, a metal coating, an intermediate active layer and an outer dampproof layer, wherein the metal coating covers the outer surface of the inner core of the solder; the intermediate active layer covers the outer part of the metal coating; the outer dampproof layer is adhered to the outer part of the intermediate active layer; the inner core of the solder is spring shaped solder; the metal coating is a tinning layer or an indium plating layer; the intermediate active layer is a high-activity soldering flux; and the outer dampproof layer is an organic adhering agent. Compared with an existing self-contained soldering flux type solder, the self-contained soldering flux type solder ring has the advantages that only the outer dampproof layer contains a low-carbon-residue organic adhering agent, so thatthe quantity of used organic adhering agents is greatly decreased, and harmful gas produced by the combustion of the adhering agent in soldering is greatly reduced, and as a result, the body health ofoperators is ensured; the environmental pollution is reduced; and the environment protection is achieved; and meanwhile, inclusions produced by carbon residual in soldering seams can be avoided, andthus the soldering reliability is improved.

Description

technical field [0001] The invention relates to the technical field of welding materials, in particular to a self-contained flux type solder ring and a preparation method thereof. Background technique [0002] The traditional brazing process of pipelines in air conditioners, refrigerators and other industries uses manual flame brazing of wire or strip solder. The heating time is longer when welding metals with fast heat conduction such as copper. When brazing, wire or strip-shaped solder is used to apply the flux to the workpiece before heating or pre-heating. The amount of solder can not be guaranteed, and problems such as solder leakage and solder blockage are prone to occur, followed by Rework, rework or even scrapping will cause waste of solder and raw materials and increase manufacturing costs. In addition, the operation of solder paste or pre-coated flux increases the pre-soldering process and operation time, and adds another variable in the brazing process, thereby ...

AI Technical Summary

Problems solved by technology

[0004] At present, only flux-cored solder rings and self-contained flux-type solder rings are used in pipeline brazing. Since the processing performance of flux-cored solder is restricted by its composition, many component drugs The core solder has the defect of poor deep processing performance. It can only be prepared into strips, and it is difficult to prepare ring-shaped flux core solder. Preparation method: Roll the solder into a strip shape, then roll the solder strip into a U-shaped groove, add flux , and finally through multi-pass rolling joints to form O-shaped tubular structure flux-cored solder, and then prepared into flux-cored solder by drawing and reducing the diameter. The most promising application prospect for pipeline brazing in air conditioners, refrigerators and other industries is Self-contained flux type solder ring

However, there are three disadvantages in the self-contained flux-type solder ring disclosed at present: 1. For the convenience of assembly, the inner diameter of the self-contained flux-type solder ring is often larger than the outer diameter of the welded pipeline, and the internal and external diameter of the self-contained flux-type solder ring is larger than that of the welded pipeline. The rings have a flux layer, and the flux layer is too thick, resulting in slow heat transfer between the welded pipe and the welding ring during induction heating. During high-frequency induction brazing, the welded pipe is heated, and the heat is transferred from the welded pipe to the self-brazing ring. Formulation solder ring, after reaching the melting point of the solder, melts and wets, and fills the gap of the pipe to be welded, which affects the brazing efficiency; 2. The flux layer of the self-contained flux-type solder ring often contains boric anhydride, potassium fluoride, etc. Inorganic substances are easy to absorb moisture and fall off blocks, and the flux layer after moisture absorption is corrosive, which severely corrodes the solder core covered by the flux layer, especially the copper-phosphorus solder is easy to oxidize and corrode. "Rust", the "rust" of the solder core will seriously affect the appearance and performance of the self-contained flux-type solder ring. In order to prevent the solder core from being corroded after the flux layer absorbs moisture, it is necessary to choose a solder core with weak moisture absorption. Flux, which leads to very low flux activity. The main function of flux is to remove the oxide film on the surface of the metal to be welded and protect the metal to be welded from oxidation. The activity of the flux mainly refers to the ability to remove the oxide film; Flux-type solder, by adding an excessive amount of organic binder to the flux layer to avoid its moisture absorption, mixing the organic binder and flux to prepare a flux paste, and then coating it into a self-flux type solder China Patent CN202804495 U discloses "a kind of solder coated with coating", which is to laminate and coat brazing flux on the solder rod; the signed article "Development of coated brass solder" introduces the The coating is to mix the organic adhesive and flux first, and then apply the flux with the adhesive to the surface of the brass brass.

, this self-contained flux-type solder contains a large amount of organic adhesives. During the brazing process, the organic adhesives are decomposed and carbonized by heat, and a large amount of harmful gases are generated, which not only pollutes the environment, but also damages the operator's body. Healthy, very environmentally friendly; at the same time, carbon residues in the brazing seam produce inclusions, reducing brazing reliability

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