Vacuum Brazing

VACUUM BRAZING

Vacuum brazing is a term for various metal joining or brazing processes that take place in a chamber or retort below atmospheric pressure, otherwise known as a vacuum furnace. Vacuum brazing is brazing in a furnace using a vacuum atmosphere.

A vacuum furnace is a furnace using low atmospheric pressures instead of a protective gas atmosphere like most heat treating furnaces.  Furnaces are categorized as hot wall or cold wall, depending on the location of the heating and insulating components. Cold wall furnaces are used in vacuum brazing

Assemblies are bright and clean (shiny) after vacuum brazing because the extremely low amount oxygen in a vacuum atmosphere prevents oxidation of parts. Vacuum brazing is particularly useful where base metals are processed that adversely react with other atmospheres, or where entrapped fluxes or gases are intolerable. Vacuum brazing is widely used to braze base metals of stainless steel, super alloys and carbon low alloy steels.

Vacuum brazing offers the combination of high cleanliness and uniform heating and cooling or rapid cooling. Vacuum brazing is ideal for oxidation sensitive materials such as those used in the aerospace industry.

Wall Colmonoy Corporation is the pioneer in furnace brazing of high-temperature base metals using nickel-based filler metals. Additionally, Wall Colmonoy Dayton, Ohio has eight brazing/heat treating furnaces, including the world’s largest top-loading vacuum furnace at 120” dia. X 180” high and vacuum brazing is one of their specialties. Since 1959, Wall Colmonoy Dayton has specialized in furnace brazing--including hydrogen and vacuum brazing--and thermal processing of all types of metals. With furnaces handling work loads of up to 10 tons and quality assurance procedures to aerospace requirements, Wall Colmonoy Dayton has the capabilities and experience to handle as much (or as little) as you need.

Brazing is broadly defined as a group of joining processes that occur above 840 degrees F (400 degrees C) and below the melting point of the base metal. Additionally, brazing produces coalescence by the melting and subsequent resolidification of a filler metal or brazing alloy in the very narrow space between surfaces to be joined. The brazing alloy or brazing filler metal must have a lower melting point than the material being joined, because in brazing the base metal does not melt. In conventional brazing, molten filler metal  is distributed between closely fitted surfaces of the base metal joint by capillary action – even against gravity.

Most of the common metals can be brazed, but not necessarily with the same brazing filler metal equipment, method, or procedure.

Wall Colmonoy Dayton offers the quality assurance of non-destructive testing, is ISO 9001: 2000 registered and NADCAP accredited for heat treating, furnace brazing and hardness testing.

Call or email today and Wall Colmonoy Dayton's brazing and heat treating experts will help you determine the best thermal processing or brazing service to meet your needs.