| 摘要 |
PURPOSE:To maintain the amt. of the atmosphere gas during carburization at a required min. specified amt. and to considerably decrease the consumption of a base gas for forming the atmosphere gas by decreasing the amt. of the base gas in proportion to the amt. of an enriching gas to be added at the time of making a gas carburization treatment of a metal. CONSTITUTION:Steel products to be treated are put into a muffle type carburization furnace 1 and the surface thereof are subjected to gas carburization treatment. Gaseous N2, 5 and org. liquid 9 of a lower alcohol such as methanol or ethanol are supplied respectively through flow rate control mechanism 3, 7 as the base gas to be supplied to the carburization furnace. On the other hand, the supply rate of gaseous hydrocarbon such as CH4 or C2H6 as the enriching gas 13 is automatically controlled by a controller 17 and a flow rate control mechanism 11 in such a manner that the equil. carbon concn. of the atmosphere gas in the stage of the carburization process (3hr at 930 deg.C) in the carburization furnace attains 1.1% and that the equil. carbon concn. of the atmosphere gas in a diffusion process (1.5hr at 930 deg.C) attains 0.8%. The amt. of the base gas is thus efficiently and effectively used and is made considerably lower than heretofore.
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