Experience with Excess Pressure Gas Quenching and Carburization in Vacuum Furnaces.

For accelerated gas quenching of workpieces during hardening in vacuum furnaces a new furnace was developed in which quenching occurs under a pressure of up to 5 bar. The hitherto attainable quenching rate is increased thereby severalfold. It was found that during carburization in vacuum furnaces the swirling of the gas in the combustion chamber, combined with periodically repeated and controlled pressure oscillations, leads to good uniformity in the carburization of production heats.