Brazing is to use a metal material with a lower melting point than the workpiece as the brazing material. The workpiece and the brazing material are heated to a temperature higher than the melting point of the solder and lower than the melting point of the workpiece. The workpiece is wetted with liquid solder, filling the interface gap and achieving the same Inter-diffusion between atoms to achieve a welding method.

The seam formed when welding joins two connected objects is called a weld. Both sides of the weld seam will be subjected to welding heat during welding, and the structure and properties will change. This area is called the heat affected zone. Due to different welding materials and welding currents during welding, overheating, embrittlement, hardening or softening may occur in the weld and heat affected zone after welding, which also reduces the performance of the weldment and deteriorates the weldability. This requires adjustment of welding conditions. Pre-heating of the weldment interface before welding, heat preservation during welding, and post-weld heat treatment can improve the welding quality of the weldment.