CONTROLLING METHOD OF CARBURIZING ATMOSPHERE FOR BATCH TYPE CARBURIZING FURNACE

摘要

PURPOSE:To enable adequate control of the carburizing atmosphere in a batch type carburizing furnace by measuring the concn. of the specific gas in the furnace with respect to the carbon potential in the stage of starting carburization with said furnace and controlling variably the flow rate of the enriched gas thereafter with the actually measured value as a reference. CONSTITUTION:An object to be treated such as a steel product or the like of which the surface is to be carburized is charged into a batch type carburizing furnace and the concn. of CO2 in the atmosphere in the furnace at the point (f) of starting carburization after heating-up is measured actually with an IR analyzer or the like. An ideal curve B at which the concn. fluctuates with time is stored in a calculator in the carburizating treatment which decreases the concn. of CO2 in the furnace to C1 after the time T from the point (f). The flow rate of the enriching gas is variably controlled in such a way that the target concn. C1 of CO2 in the furnace is attained after the time T from the point (f) according to the curve for the set value (a dotted line A if the actually measured value is high and a dotted line C if said value is low) obtd. by correcting and calculating the ideal curve B with the actually measured value of the concn. of CO2 in the furnace at the point (f) as a starting point.