What are the solders and fluxes used for inductor brazing? How to choose?
Most of the metal parts such as the body and the liquid sprayer used on the sensor are pure copper, brass, as well as stainless steel and cemented carbide. The solders are mainly copper solder, brass solder, silver copper solder and tin solder. The brazing temperature of the first three solders is higher than 500 ℃, which is called brazing (or brazing), and the latter one is called soft soldering (or brazing). Soldering). See Table 1 for the composition, melting point and application of the soldering material for inductor brazing, and Table 2 for the composition, melting point and application of the soldering material for inductor soldering.
Table 1 The composition, melting point and application of welding materials for brazing of inductors
Generally, the solder is selected according to the brazing part. It is best to use silver solder for the joint of the conductive part, because the conductivity of silver solder (IACS) is higher, such as w (Ag) = 72%, w (Cu) = 28% of the solder, the conductivity reaches 87%. Another factor to consider is the liquidus point of the solder, such as w(Ag)=45%, w(Cu)=15%, w(Zn)=16%, w(Cd)=14% solder has lower The liquid point of 620 ℃. This kind of solder is often used when the brazing temperature of the brazing part is required to be low.
In addition, brass welding can be used for non-conductive parts such as water boxes and liquid sprayers, and low-silver electrodes are often used for the connection between the copper tubes of the effective ring, such as w(Ag)=15%, which has a slightly higher liquidus point (> 800℃) and lower price. Pure copper welding wire is often used in part of the pipe, first spot welding, and then use low silver welding wire to weld the entire welding seam. Tin welding is soft soldering, and its melting point is low. It is often used for the connection of heat dissipation copper pipes and copper plates. There is no direct current passing through, but the water in the copper pipe takes away the heat on the welded copper plate. The heat dissipation plate of the intermediate frequency transformer and the brass side plate of the crankshaft inductor are commonly used for the connection between the heat dissipation pipe and the plate.