DETECTION FOR AIR CHARGING POSITION TO VACUUM VESSEL SYSTEM IN VACUUM REFINING OF MOLTEN STEEL

摘要

PURPOSE:To detect quickly and accurately a position through which air is charged to a vacuum vessel system, by blowing an inert gas to all seal parts of the vacuum vessel system successively to measure the sensitivity to the inert gas. CONSTITUTION:The pressure in a vacuum vessel system consisting of a vessel 1 and an attachable and detachable vessel cover 2 is reduced by an air discharge system 5. Oxygen is blown from a lance 7 onto a molten steel in a ladle 6. The degradation of the degree of vacuum is due to the lowering of the air discharge capability of the air discharge system 5 or the defect of air-tightness in a seal part (A), (B), or (C). An inert gas is blown to seal parts successively from preliminarily installed pipings 9, and discharge gas samples are analyzed with a mass spectrograph, and a position of the defect of airtightness is discriminated on a basis of the variance of measured values before and after blowing. Thus, the cause position is detected quickly and accurately without stopping the operation.