Preparation method of flux coated silver solder ring

Abstract

The invention relates to a preparation method of a flux coated silver solder ring. The method comprises the steps of 1, preparing the following raw materials: 10-50% of Ag, 15-45% of Cu, 17-40% of Zn,1-3% of Sn, 0.1-0.5% of P, 0.5-2% of Ni, 0.1-0.3% of Ge, and 0.1-0.3% of Li; adding the raw materials to an intermediate-frequency smelting furnace crucible; performing smelting, casting, extruding and drawing to obtain silver solder wires; and preparing multi-coil spring shaped silver solder ring through the silver solder wires; 2, preparing 1-5% of boron micro powder, 5-10% of sodium borohydride, 15-30% of potassium fluoborate, 25-40% of boric anhydride, 10-30% of sodium fluoride, 2-5% of potassium bifluoride, 1-5% of copper sulfate, 0.1-2% of polystyrene, and 0.2-2% of dibutyl phthalate; mixing the materials; adding 45% of ethyl acetate; and uniformly stirring to obtain a flux coating solution for later use; and 3, spraying the flux coating solution to cover the outer parts of the spring shaped silver solder ring; and drying to obtain the flux coated silver solder ring. The flux coated silver solder ring prepared by the method is high in wettability, high in flowability, and capable of self-fluxing; zinc is hard to volatilize; and moreover, the flux coating is high in activity, low in moisture absorption capacity, few in carbon residues, high in ductility and toughness, and isparticularly applicable to soldering of pipeline assemblies such as a stainless steel pipeline assembly and a manganese brass pipeline assembly.

Description

technical field [0001] The invention relates to the technical field of welding materials, in particular to a method for preparing a coated silver solder ring. Background technique [0002] 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, which can only be prepared into strips, and it is difficult to prepare into a ring (the preparation method of the core solder is: the solder is rolled into a strip shape, and then the solder strip is rolled into a U-shaped groove, and the solder is added Finally, through multi-pass rolling joints to form O-shaped tubular structure flux core solder, and then draw and reduce the diameter to prepare flux core solder), the most promising application prospects for pipeline brazing in air conditioners, refriger...

AI Technical Summary

Problems solved by technology

[0002] 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, which can only be prepared into strips, and it is difficult to prepare into a ring (the preparation method of the core solder is: the solder is rolled into a strip shape, and then the solder strip is rolled into a U-shaped groove, and the solder is added Finally, through multi-pass rolling joints to form O-shaped tubular structure flux core solder, and then draw and reduce the diameter to prepare flux core solder), the most promising application prospects for pipeline brazing in air conditioners, refrigerators and other industries coated silver brazing rod

However, the self-contained flux-type solder ring disclosed at present has the following disadvantages: during induction heating, in order to ensure brazing efficiency and joint quality, heat must be transferred rapidly between the silver-coated brazing rod and the pipeline to be welded, so the silver-coated brazing rod must The thickness of the coating in the brazing rod should not be too thick, otherwise it will affect the heat transfer efficiency

In order to ensure the ability of the traditional Chinese medicine skin to remove the oxide film, it is necessary to increase the activity of the flux in the coating. Therefore, the coating of the silver brazing rod often contains boric anhydride, potassium fluoride, potassium hydrogen fluoride and other inorganic substances, which are easy to absorb moisture and The pieces fall off, and the flux layer after moisture absorption is corrosive, which seriously corrodes the solder core covered by the coating, especially the copper-phosphorus solder is easy to oxidize, corrode and "rust", and the solder core "rusts". "rust" will seriously affect the storage, transportation, appearance and performance of the coated silver brazing rod. In order to avoid corrosion of the solder core after the coating absorbs moisture, a flux with weak moisture absorption has to be selected, which will lead to the activity of the flux. Very low (the main function of the flux is to remove the oxide film on the surface of the metal to be welded and to protect the metal to be welded from oxidation, and the activity of the flux mainly refers to the ability to remove the oxide film); when brazing stainless steel and manganese brass, Cr on the surface 2 o 3 、TiO 2 and MnO 2 It is relatively stable and difficult to remove; in current projects, a layer of copper or nickel is plated on the surface of difficult-to-braze metals to improve its brazeability, but whether electroplating or electroless plating is used to add a process, the operation is complicated, the cost is also increased, and it is harmful to the environment. serious pollution

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