A copper-based solder that can accurately control the amount of flux and has a good protection effect on the brazing seam

Abstract

The invention belongs to the field of welding materials, in particular to a copper-based solder that can accurately control the amount of flux and has a good protective effect on the brazing seam, including a circular or oval copper-based solder inner wire and a protective film. The protective film includes: Zinc phosphide powder 10%‑12%, kyanite powder 5%‑7%, glass fiber 3%‑5%, nano silicon dioxide powder 2.5%‑3.5%, boric anhydride powder 10%‑12%, potassium fluoroborate Powder 20%-25%, the above substances are treated with coupling agent, there is also 5.5%-6.5% curing agent, and the balance is epoxy resin. In the preparation process of the present invention, there will be no wire breakage, and the solder has strong wettability during brazing, which can effectively fill the gaps between the workpieces to be welded; the amount of brazing flux can be precisely controlled during brazing, which solves the problem of brazing Insufficient dosage or too much flux residue after brazing; the protection effect on the brazing seam is good during brazing and the protective layer is easy to remove, the brazing seam has fewer defects and high strength.

Description

technical field [0001] The invention belongs to the technical field of welding materials, in particular to a copper-based solder that can precisely control the amount of flux and has a good protective effect on brazing seams. Background technique [0002] With the rapid development of industrial technologies such as automobiles, microelectronics, electrical appliances, tools, refrigeration, exploration, tunneling, aerospace, etc., brazing technology has been widely used in these fields due to its unique advantages. For copper alloys, copper-based solder is required for brazing. Generally, copper-based solder is used in conjunction with flux. Flux is used to remove the oxide film on the surface of the base metal and protect the brazed joint from oxidation. [0003] At present, there are two types of copper-based solders commonly used: solid solder and cored solder. During the preparation and use, there are the following technical problems: [0004] (1) When using solid coppe...

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Problems solved by technology

[0004] (1) When using solid copper-based solder: ① In order to increase the wettability during brazing and dilute the melted solder, most of the chemical composition of the solder contains phosphorus, so that it can be enhanced after the solder is melted. Fluidity, so as to achieve the purpose of filling the gap to obtain a perfect brazing joint, but the existence of phosphorus element, it is easy to form a low-melting eutectic structure Cu+Cu with a melting temperature of about 714 ° C in copper alloy 3 The P brittle phase leads to increased brittleness of the solder at room temperature and a decrease in toughness. The copper-based solder wire can only be squeezed or drawn in a hot state, and it is easy to break, reducing the single copper-based solder wire. length, which increases the difficulty in the preparation process; ② When using flux, one method is to apply it on the surface of the solder, and the other is to apply it on the surface of the workpiece to be welded, but the amount of flux added cannot be precisely controlled, and there is often flux Excessive use will cause the problem of excessive flux residue after welding. The use of excessive flux will generate a lot of smoke and dust, seriously pollute the environment, and endanger the health of operators, and there is a great potential safety hazard; ③Protection of the brazing seam during brazing The effect is not good, the obtained brazing seam has defects such as pores, and the brazing seam strength is low

[0005] (2) When using flux-cored copper-based solder: ①During the drawing process of the preparation, the outer skin copper alloy undergoes plastic deformation, the diameter of the outer tubular solder is reduced and the length is extended, and the powdered flux filled in the core is not connected. Strength, plastic deformation will not occur during drawing and diameter reduction, radial and longitudinal flow is difficult, causing the flux to be compacted, hindering the plastic deformation of the solder, making the flux-cored solder particularly easy to break, reducing the copper-based The single length of flux-cored solder wire reduces the production efficiency; ②The protective effect on the brazing seam during brazing is not good, the obtained brazing seam has defects such as pores, and the brazing seam strength is low

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