What is brazing material?

First of all, we should know what brazing is.

Brazing: a welding method in which the brazing filler metal with a melting point lower than that of the base metal is heated and melted, and then the base metal is wetted with liquid brazing filler metal to fill the joint gap and diffuse with the base metal to realize the connection.

The filler metal used in brazing is called solder.

Basic requirements of solder:

(1) is lower than the melting point of the workpiece metal;

② Sufficient wettability (the performance of solder flowing into the gap);

(3) It has the proper ability to dissolve and diffuse the workpiece metal;

④ Welded joints should have certain mechanical, physical and chemical properties.

According to different melting points, solder can be divided into soft solder and hard solder.

(1) Soft solder: solder with melting point below 450℃, including tin-lead base and lead base (T

Soft solder is mainly used for welding workpieces with low stress and low working temperature, such as the connection of various wires and the brazing of instrument parts (mainly used for welding electronic circuits).

Commonly used soft solders are: tin-lead solder (the most widely used, with good manufacturability and conductivity, T.

Soft soldering: refers to soldering with soft solder. The strength of brazed joint is low (less than 70Mpa).

(2) Hard solder: that is, solder with melting point higher than 450℃, including aluminum-based, copper-based, silver-based and nickel-based alloys.

Solder is mainly used for welding workpieces with high stress and high working temperature, such as bicycle frames, cemented carbide tools and drill bits (mainly used for welding mechanical parts).

Commonly used solders are: copper-based solder and silver-based solder (the most widely used solder has good mechanical properties, electrical and thermal conductivity and corrosion resistance. Widely used for brazing low carbon steel, structural steel, stainless steel, copper and copper alloys. ), aluminum-based solders (mainly used for brazing aluminum and aluminum alloys) and nickel-based solders (mainly used in aerospace departments).

Brazing: refers to brazing with brazing filler metal. The strength of brazed joint is high (more than 200Mpa).