Automatic control of the carbon potential of furnace atmospheres without adding enriched gas

An approach has been proposed in this article for controlling the carbon potential of furnace atmosphere without the need to add enriched gas for the sake of simplifying the process of carbon potential control and consequently lowering the cost of atmosphere. The atmosphere was generated by reacting an N₂ + H₂O mixture with hot charcoal. An oxygen sensor and a computer were used for controlling the carbon potential of the atmosphere through controlling the temperature of charcoal instead of adding an enriched gas to the atmosphere. The control result was evaluated from (a) the stability of oxygen partial pressure of the furnace atmosphere and (b) the equilibrium carbon content of the steel heated in the furnace atmosphere. The result of controlling carbon potential with this method was indicated by observed experiments to be satisfactory;i.e., the deviation of carbon potential was below 0.06 pct. There was especially no need to add enriched gases to the atmosphere.