Aluminum Vacuum Brazing
- We establish a partnership with you to achieve the desired aluminum brazing result via consultation and coordination.
- To work with you to improve the design of parts and lower overall brazing costs.
- To use our extensive national network of aluminum vacuum brazing experts to structure your project for maximum efficiency and success.
- Security and confidentiality for all aspects of your project.
- A clean metallurgical bond to your exact specifications. Every part will visually inspected, pressure tested if needed prior to packaging and shipping.
Vacuum Aluminum Brazing
Vacuum aluminum brazing is a vacuum furnace joining process that specifically involves aluminum and various aluminum alloys. Since it takes place in a vacuum, the brazing process occurs significantly below atmospheric pressure. When compared with other processes, this joining technique offers significant advantages: durable, flux-free aluminum joints. During the vacuum heating process itself, the aluminum’s temperature is stringently kept at a single level.
Vacuum aluminum brazing is chiefly executed by means of a furnace, meaning that different joints can be combined all at once even as the overall aluminum part reaches its necessary brazing temperature. It also means that thin and thick part cross-sections can be easily joined together. The heat is then transferred from the furnace heating elements to the aluminum component via radiation.
Vacuum brazing is a high-end joining technology because it results in parts with extremely strong joints and with no residual corrosive flux. It is a process in which two base metals, such as aluminum plates, are joined together using a filler metal that has a melting point below that of the base metal. The filler metal, also known as a braze alloy, is drawn into the closely mated parallel surfaces of the aluminum plates by capillary action. The attributes of the vacuum brazing process include uniform heating, tight temperature control, no post cleaning processes, and process repeatability.
Vacuum Aluminum Brazing (CAB) Controlled Atmosphere Brazing
CAB Brazing specializes vacuum aluminum brazing, using nitrogen to control the atmosphere during the brazing process.
Modern Metal Processing uses Controlled Atmosphere Brazing (CAB) as a batch process to braze some aluminum heat exchangers and other mechanical assemblies. The CAB process uses an inert gas, mostly Nitrogen, for the gas environment to ensure superior joint strength. Filler metal, most commonly an aluminum-silicon alloy (usually 4047) will flow quickly when melted and create strong joints post-braze. Flux, which could be non-corrosive or corrosive for aluminum applications, helps to reduce oxides on the metal surface. This allows the filler metal to flow and make a strong braze joint.
Another benefit of CAB is the use of a cover gas. While flux is still required in a CAB process for aluminum, the controlled atmosphere helps minimize the amount of flux needed. This means less flux voids in joints and less flux residue after brazing, which offers an improved aesthetic benefit. The protective atmosphere also helps to keep further oxidation from occurring, which allows for the braze alloy to flow more freely and form higher quality joints.
By using a CAB process that provides even heat for every joint, variation from part to part is decreased, and the final joints formed are much more robust. The furnace allows for even heating of all parts, big or small, while the controlled atmosphere keeps a constant flow of protective gas around every braze joint simultaneously. This results in a more economical braze process as more parts can be brazed at once, while leaks and costly repairs are minimized.