What is brazing?

Brazing refers to a welding method in which the solder below the melting point of the weldment and the weldment are heated to the melting temperature of the solder at the same time, and the gap of the solid workpiece is filled with liquid solder to connect the metals.

Brazing methods include: high frequency induction brazing, flame brazing, resistance brazing, furnace brazing, phase brazing, soldering iron brazing, ultrasonic brazing, etc.

The brazing deformation is small, and the joint is smooth and beautiful. It is suitable for welding parts made of precise, complex and different materials, such as honeycomb structural plates, turbine blades, cemented carbide tools and printed circuit boards. Before brazing, the workpiece must be carefully processed and strictly cleaned to remove oil stains and excessive oxide films and ensure the assembly clearance of the interface.

Extended data:

Most flux residues will corrode brazed joints and hinder the inspection of brazed joints, so it is often necessary to clean them. The residue of active flux containing rosin can be removed by organic solvents such as isopropanol, ethanol and trichloroethylene.

Brazing agents composed of organic acids and salts are usually soluble in water and can be cleaned with hot water. Soft solder composed of inorganic acid is soluble in water, so it can be cleaned with hot water. Fluxes containing alkali metal and alkaline earth metal chlorides (such as zinc chloride) can be cleaned with 2% hydrochloric acid solution.

Borax and boric acid flux residues for brazing are basically insoluble in water and difficult to remove. Generally, they are removed by sandblasting. A better method is to put the brazed workpiece into hot water, so that the flux residue can be cracked and easily removed.