Brazing is below the melting point of weldment heat solder to solder melting temperature, using liquid solder fill solid workpiece aperture, make metal connection way of welding, brazing belong to solid connection, it is different from welding method, brazing artifacts not melt, melt but are lower than those of workpiece melting temperature of solder, soldering is not applicable to the general steel structure, overloading, dynamic load part of welding, it is mainly used for close instrument, electrical components and complex welding of thin plate structure, according to the melting point of solder is different, can be divided into two kinds of soft soldering and brazing.

The melting point of the solder for soft brazing will be below 450 ° C and the joint strength will be low. It is used for workpieces with low stress or low working temperature. Tin and lead alloys are commonly used as solder, such as those used in the electronics industry.

Brazing solder will be above 450 degrees Celsius, joint strength will be higher, silver, copper as the filler metal, such as some hard alloy turning tool, alloy bit welding is used brazing.

As a very important technology in modern production and processing, welding has made great contributions to the fields of architecture, national defense, aerospace and so on.