Cadmium-free silver-based brazing filler metal

Abstract

The invention provides cadmium-free silver-based brazing filler metal which is prepared from, by weight, 28-38% of Ag, 20-30% of Zn, 1-3% of Mg, 2-4% of Sn, 0.6-1.3% of Ni, 0.04-0.16% of NaF, 0.3-1.2% of P and the balance Cu. The cadmium-free silver-based brazing filler metal is low in silver content, contains no cadmium element, is low in melting temperature, high in corrosion resistance and good in machining performance, is the multi-element silver brazing filler metal and is used for brazing red copper, brass and stainless steel.

Description

technical field [0001] The invention belongs to the technical field of brazing materials, and in particular relates to a cadmium-free silver-based brazing material. Background technique [0002] When brazing copper and copper alloys with ferrous metals such as iron and their alloys, considering the wettability of the brazing material to the brazing base material and the mechanical properties of the brazed joint, most people choose silver solder. Four-way valve, a control valve with four oil ports, is an indispensable key component in refrigeration equipment. The cold and hot gas circulates, and the working environment is relatively harsh. It needs to be welded with silver solder with strong reliability. The four-way valve is welded The requirements are very high reliability, fatigue resistance, good corrosion resistance, and high welding strength. BAg45CuZnCd and BAg45CuZn are commonly used, but as the price of precious metal raw materials continues to rise, manufacturers w...

AI Technical Summary

Problems solved by technology

[0003] Some companies reduce the silver content by increasing the content of Cd. The addition of Cd greatly reduces the melting temperature of the solder, improves the brazing performance, and reduces the silver content. It was once widely tested, but Cd itself is Toxic elements are not conducive to the health of operators and pollute the environment. They do not comply with the EU RoHS directive. As people pay more and more attention to environmental protection, they are gradually replaced by other harmless elements.

Some enterprises adopt multi-element alloying and develop silver brazing material with a silver content of about 20% as a substitute. However, due to the difficulty of processing and forming in multi-element alloying, its price is still not acceptable to some customers.