APPARATUS AND METHODS FOR GENERATING AN ARTIFICIAL ATMOSPHERE FOR THE HEAT TREATING OF MATERIALS

摘要

An apparatus and method for generating artificial atmospheres in a furnace for the heat treating of materials. The furnace includes a substantially isolated chamber having a discharge receiving orifice for accepting a bi-phasic cryogen into a hot/work zone of the chamber. A low pressure cryogen source feeds a bi-phasic inert gas into the chamber in order to allow the volumetric expansion of the evaporating liquid constituent of the biphasic cryogen to purge a substantial portion of the ambient oxygen from the chamber and to allow a substantial residual concentration of the inert gas to blanket the process area without significant dissipation during the heat treating process. Oxidizable materials heat treated in artificial atmospheres generated by use of bi-phasic cryogens show no signs of scaling or staining through the process and thus do not need to undergo acid bathing prior to subsequent processing.