Brazing is a welding process in which the solder below the melting point of the joint and the joint are simultaneously heated to the melting temperature of the joint and the gap of the solid workpiece is filled by a liquid filler to join the metal.In the brazing process, the oxide film and grease on the contact surface of the base metal must be removed first so that the capillary can function after the solder melts and increase the wettability and fluidity of the capillary.According to the melting point of solder, brazing is divided into hard brazing and soft brazing.

Small brazing deformation, smooth and beautiful joints, suitable for welding precision, complex, honeycomb structure plate, turbine blade, carbide tools, printed circuit boards and other materials.Before brazing, the workpiece must be carefully machined and cleaned to remove oil stains and thick oxide film to ensure the interface assembly clearance.Clearance is usually required between 0.01 and 0.1 mm

Compared with fusion welding, the base metal does not melt, only the filler metal does.

In contrast to pressure welding, no pressure is applied to the solder during brazing.

The weld formed by brazing is called brazing weld.

The filler metal used for brazing is called brazing filler metal.

Brazing process: clean surfaces of the workpiece are assembled together in lap, brazing filler metal is placed near or between the joint clearance.When the workpiece and solder are heated to a temperature slightly above the solder melting point, the solder melts (the workpiece is not melted), and the gap between the solid workpiece, the liquid solder and the workpiece metal is sucked and filled by capillary action, which diffuses and dissolves after condensation, forming the soldering joint.