Brazing
Brazing is the process of fusing two different materials together using a solder which has a melting point higher than 450oC (840oF) .
Before Brazing takes place, Flux must be added to the brazing area of both materials, commonly known as ‘wetting’. The purpose of the Flux is to provide a clean, oxide free surface which allows the filler to flow easily throughout the joint.
There are 3 general bonding methods:
Conduction - is when the joint is heated using a soldering iron, the solder is applied to the heated joint, causing it to melt. If it is not possible to heat the joint up, the solder can be melted directly by the soldering iron and placed onto the joint. This method is commonly used on circuits board and is suited for use on through joints.
Torch - is when a gas torch is used to heat up the joint, the solder is then added, typically this method is used to bond faces of material. The two workpieces must be positioned with a small gap between then to allow the solder to be drawn through the gap.
Furnace - is when the solder is sandwiched between two work pieces, the whole assembly is then fed into a furnace, where it is heated causing the solder to melt, the workpiece is then removed from the furnace and left to cool. The method is ideal for mass production and forming multiple joints at once.
Common methods of brazing are:
• Atmosphere Furnace
• Vacuum Brazing
• Salt Bath (Dip) Brazing
• Induction Brazing
• Manual Flame Brazing