Soldering tin capable of not dissolving copper

Abstract

The invention discloses soldering tin capable of not dissolving copper. The soldering tin comprises, by weight, 97.09-97.69 parts of tin, 0.1-2.0 parts of nickel, 0.1-1.5 parts of copper, 0.01 part of phosphorus and 0.1 part of bismuth. According to the soldering tin, due to the fact that the copper dissolving speed is very low, welding time can be greatly prolonged, the dissolving speed problem of copper in the soldering tin is not considered, hence, it is guaranteed that a paint film of a polyurethane varnished wire can be evaporated completely, perfect welding spots can be formed, the wire diameter of a copper wire is basically unchanged, and electrical strength can be reliably guaranteed.

Description

technical field [0001] The invention relates to copper-insoluble solder and belongs to the field of metal materials. Background technique [0002] At present, when polyurethane enameled wires (straight welding wires for short) are used in motors or transformers, the process of direct welding (dipping tin welding, no paint removal) with lead wires or terminal windings is generally adopted, which is more convenient to operate, but the huge defect of this process is Since the paint film on the surface of the enameled wire needs to be scalded directly, a higher temperature is required, generally at least 380 degrees Celsius, and most manufacturers use a temperature of 450 degrees Celsius. Some polyurethane enameled wires have thicker paint films and require higher temperatures. At high temperature, the solder and the copper of the enameled wire can react to form a metal compound of SN6CU5, which causes the enameled wire to dissolve quickly in the solder, and the enameled wire wi...

AI Technical Summary

Problems solved by technology

[0002] At present, when polyurethane enameled wires (straight welding wires for short) are used in motors or transformers, the process of direct welding (dipping tin welding, no paint removal) with lead wires or terminal windings is generally adopted, which is more convenient to operate, but the huge defect of this process is Since the paint film on the surface of the enameled wire needs to be scalded directly, a higher temperature is required, generally at least 380 degrees Celsius, and most manufacturers use a temperature of 450 degrees Celsius. Some polyurethane enameled wires have thicker paint films and require higher temperatures. At high temperature, the solder and the copper of the enameled wire can react to form a metal compound of SN6CU5, which causes the enameled wire to dissolve quickly in the solder, and the enameled wire with a smaller wire diameter dissolves faster. For example, the enameled wire with a diameter of 0.2 mm becomes thinner at 450 degrees Celsius in 3 seconds , It can be completely dissolved in the tin furnace in 5 seconds. If the time is shortened, it cannot guarantee that the paint film of the enameled wire can be completely vaporized, which will affect the welding quality. It still affects the welding quality, so the dissolution of copper by solder is a major obstacle to the polyurethane enameled wire process

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