Nitrogen can be used to purge heat treat furnaces and reflow solder baths which prevents oxidation of the metal surface and minimizes dross generation. Nitrogen is often used to blanket furnaces to eliminate oxygen. This is done because of oxygen’s tendency to react with certain metals when it’s at a high temperature. Applications that require oxygen free environments include neutral hardening, carbonizing, carbon nitriding, and tempering. Nitrogen is also used as an assist gas to help the processing of materials by laser cutting.