Process Description
Brazing is a joining process that is highly flexible in terms of the composition of components that can be brazed, the geometry of the components, the geometry of the braze joint and the types of heat sources used to melt the braze filler alloy. The joins produced are strong and metallurgically bonded to the substrate.

Brazing differs from welding in that only the braze filler metal is melted in the process. There is no melting of the component substrate and therefore, no heat affected zone. Properly performed, the braze process will not distort the joined components. Brazing differs from soldering in terms of the melting point of the filler metal used for joining. Braze filler metals melt at or above temperatures of 450 °C (840 °F), soldering filler metals below these temperatures.

The composition of braze filler metals are generally alloys of silver, gold, nickel, cobalt, aluminum or copper. Often, small amounts of temperature suppressants are used to reduce the melting temperature of the filler metal. These suppressants generally migrate out of the filler metal during brazing, so the remelt temperature of the braze joint is often much higher than the original brazing temperature. The heat sources that can be used range from simple torches for low melting alloys, to vacuum and retort furnaces.

Features of the Brazing Process
• Produces strong, metallurgical bonds
• Many braze joints are highly corrosion resistant
• No heat affected zone
• Little to no distortion of brazed components
• Capillary action during brazing allows joining of deep, blind joints
• Batch processing for high production rates
• Joint remelt temperature is higher than braze temperature for higher temperature service
• Wide range of braze filler materials available to suit brazing applications at different temperatures, joint gap size and configuration and substrate materials
• Available in a variety of forms (powder, paste, tape, etc.) to simplify filler metal application