| 摘要 |
PURPOSE:To considerably reduce the operating cost of a continuous heat treatment furnace by subjecting low purity gaseous N2 to deoxidation by a small amt. of gaseous H2 in a heating chamber, transferring such gas as a non-oxidating atmosphere gas to a cooling chamber and maintaining the pressure in the furnace at a prescribed value or above. CONSTITUTION:The low-purity gaseous N2 of <=99.995% purity and the gaseous H2 of <=1% the amt. of said gaseous N2 are fed into the heating chamber where the oxygen component in the gaseous N2 is rapidly brought into reaction in high-temp. environment to deoxidize. Then, the resulted gaseous N2 of non-oxygen is transferred to the cooling chamber and is maintained in an oxidation-free non-decarburizing atmosphere. The insides of the heating chamber and cooling chamber are maintained under >=150mmAQ in-furnace pressure during this time. Since the amt. of the air to be infiltered into the furnace is minimized, the smaller amt. of the gaseous N2 to be transferred is necessitated. The heat treatment in the oxidation-free non-decarburizing atmosphere is executable merely by using the small amt. of the inexpensive low-purity gaseous N2 and the small amt. of the gaseous H2 according to this invention and, therefore, the operating cost of the furnace is greatly reduced.
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