DETECTING METHOD FOR ABNORMAL DEGREE OF VACUUM IN VACUUM CONTAINER SYSTEM IN VACUUM SCOURING OF MOLTEN STEEL

摘要

PURPOSE:To detect leak, by finding the partial pressure of nitrogen of a discharge gas sample obtained by introducing inert gas and a flow rate, and then knowing the amount of air entering a vacuum container. CONSTITUTION:A vacuum degassing device consists of the vacuum container system consisting of a vessel 1 and a cover 2 and a discharge system consisting of a discharge gas duct 4 connected to it and a discharging means 5. For the vacuum scouring of molten steel, the discharge system is driven to evacuate the vessel 1 and at the same time, oxygen is blown from a lance 7 to the molten steel in a ladle. In this case, inert gas is introduced from a gas source R into the vacuum container system or discharge system through a flow meter 12 and while the partial pressure of nitrogen is determined by utilizing a sample of discharge gas containing the inert gas for a mass analysis, the ionization current value of the maximum peak that the inert gas relates to or its variation with time is measured. On the basis of those values and the flow rate of the inert gas in the discharge gas or its variation with time, the amount of air entering the vacuum container system is determined.