Low-temperature nickel-based solder for soldering

Abstract

The invention discloses low-temperature nickel-based solder for soldering. The nickel-based solder based on a NiCrSiP system comprises the following components by weight percentage: 21.5%-28% of Cr, 2.0%-3.5% of Si, 7.0%-9.0% of P and 59.5%-69.5% of Ni. The solder of the invention is superior to BNi-5 solder in both high-temperature strength and corrosion resistance, and the nickel-based solder is applicable to both the vacuum-soldering method and the method for soldering in a continuous soldering furnace under the protective atmosphere (such as nitrogen and ammonia decomposition atmosphere) and particularly suitable for soldering the metal carriers (stainless steel materials) in the automobile exhaust purifiers and automobile EGR (exhaust gas recirculation) system, thus absolutely substituting the existing BNi-5 solder.

Description

technical field [0001] The invention relates to a nickel-based brazing filler metal, in particular to a nickel-based brazing filler metal with a melting point below 1000° C. for brazing a metal carrier of an automobile exhaust purifier and an EGR of an automobile exhaust gas circulation system. Background technique [0002] In the prior art, the metal carrier of the automobile exhaust purifier (made of stainless steel) and the EGR of the automobile exhaust gas circulation system (made of stainless steel) are both vacuum brazed, and the brazing material used is BNi-5 grade. The solidus temperature of BNi-5 solder is 1080°C, the liquidus temperature is 1135°C, and the brazing temperature is 1150°C-1205°C. It can be seen that the brazing temperature is quite high when BNi-5 solder is used for brazing. The brazing temperature has a great influence on the base metal of stainless steel. For martensitic stainless steel, the brazing temperature cannot exceed 1050°C; for austenitic ...

AI Technical Summary

Problems solved by technology

[0003] Using BNi-5 solder for brazing has other disadvantages: 1. The high temperature strength and corrosion resistance of BNi-5 solder still need to be strengthened; 2. BNi-5 solder can only be used for vacuum brazing and cannot be used in Brazing in a continuous brazing furnace with atmosphere protection (for example, nitrogen, ammonia decomposition atmosphere, etc.), the brazing efficiency is relatively low and the scope of use is narrow; 3. Due to the high brazing temperature and relatively large energy consumption, the vacuum brazing furnace Service life is affected

The brazing temperature of BNi-7 solder is relatively low, but because its P content is greater than 9%, and the Cr content is not high enough, its high temperature strength and corrosion resistance are not as good as BNi-5 solder