Gas Quenching with Air

The well known ecological advantages as well as the considerable reduction of costs in the manufacturing process by gas quenching caused a rapid development of this technology. As a disadvantage the high costs of quenching gas has to be mentioned. To lower these costs the use of gas-recycling-systems is possible. But the initial costs of the systems are exalted. Additionally gas-recycling extends process time. Due to the relatively low costs and the chemical inactivity nitrogen is normally used for industrial application. The use of air instead of nitrogen would minimize the production costs. But the oxygen content of air can cause oxidation of the quenched parts and due to this damages of the surface layer. For opening a larger application field for air quenching, common statements are missing. In this article possibilities are presented, which enable the application of air as quenching medium.