Introduction and basic principles of brazing

 Brazing is a welding method. The molten filler whose melting point is lower than the workpiece to be connected is heated to higher than the melting point, so that it has sufficient fluidity, and it is fully filled between the two workpieces by capillary action, and the two are joined after solidification A method of joining together is traditionally called brazing (brazing) when the temperature is higher than 800°F (427°C) in the United States, and vice versa is called soldering (soft soldering). In order to obtain high-quality welded joints, the parts must be tightly installed and the base material must be exceptionally clean and free of oxides. In most cases, the recommended best weld gap is 0.03 to 0.08 mm (0.0012 to 0.0031 inches) to give full play to the capillary joint force. However, it is not uncommon for the weld gap to be as large as 0.6 mm (0.024in) in some cases. The cleanliness of the welding surface is very important, because any contamination will result in poor wettability of the filler metal. There are two main methods of cleaning parts before welding: chemical cleaning and grinding or other mechanical cleaning. Use mechanical cleaning to maintain proper surface roughness in addition to surface cleaning, and it is easier to fully infiltrate on a rough surface than on a smooth surface.