METHOD FOR CONTROLLING ATMOSPHERE AND PRESSURE IN HEAT TREATMENT FURNACE

摘要

PURPOSE:To control the compsn. and pressure of the atmosphere in a heat treatment furnace without the interference and to decrease the amt. of the atmosphereic gas to be used by supplying a carrier gas and enriching gas at an adequate ratio to the heat treatment furnace in the stage of controlling the compsn. and pressure of the atmosphereic gas in the heat treatment furnace. CONSTITUTION:The carbon potential CP of the atmosphereic gas is used as an operation parameter in the stage of heating indirectly steel products by radiant tubes and heat-treating said products. Gaseous NX contg. a small amt. of CO, CO2 and H2 and consisting essentially of N2 is supplied as the carrier gas and gaseous RX consisting essentially of CO, H2 and N2 as the enriching gas to the heat treatment furnace at the ratio of the gaseous NX and gaseous RX in such a manner that the CP of the ratio of the partial CO pressure with respect to the CO2 distribution of the mixed atmospheric gas attains an adequate value. The heat treatment of the steel products is thus executed with the smaller amt. of the atmosphereic gas without the mutual interference of the atmospheric gaseous pressure and CP in the gas.