Brazing Flux

Brazing flux is a material used in the brazing process to facilitate the joining of two metal surfaces. It is a chemical compound that is applied to the metal surfaces before brazing to remove oxides, prevent further oxidation during heating, and promote the flow of the brazing filler metal.

The main purpose of brazing flux is to clean the metal surfaces by removing any impurities, such as oxides, grease, or dirt, that may hinder the brazing process. It also helps to prevent the formation of new oxides during heating, which can interfere with the bonding of the metals.

Brazing fluxes come in various forms, including powders, pastes, and liquids. They are typically composed of a mixture of chemicals, such as borates, fluorides, chlorides, and carbonates. The specific composition of the flux depends on the metals being brazed and the temperature at which the brazing process is carried out.

When the brazing flux is heated, it becomes active and reacts with the oxides on the metal surfaces, forming a liquid or glassy layer. This layer acts as a barrier, preventing further oxidation and allowing the molten brazing filler metal to flow and bond the metal surfaces together.

It is important to choose the right brazing flux for the specific metals and application to ensure proper cleaning and bonding. Different fluxes have different temperature ranges and compatibility with various metals, so it is essential to follow the manufacturer's instructions and guidelines when selecting and using brazing flux.

Overall, brazing flux plays a crucial role in the brazing process by cleaning the metal surfaces, preventing oxidation, and promoting the flow of the brazing filler metal, resulting in strong and durable joints.