| 摘要 |
PROBLEM TO BE SOLVED: To detect the dropping of stuck material such as metal or slag while catching CO concn. variation in exhaust gas by charging an aluminum for deoxidation into molten steel and detecting CO concn. contained in the exhaust gas after passing a prescribed time with a CO sensor, in the case of treating the aluminum-killed steel having carbon content of a specific value or higher in a degassing vessel. SOLUTION: The aluminum-killed steel having >=0.01 wt.% carbon content is treated in an RH degassing vessel. Desirably, this detecting method of the stuck material is the one, with which an alarm is sounded considering that the stuck material is dropped in the case of raising the variation of the CO concn. to >=3%/20 sec or in the case the passing time after charging the aluminum is the uniform mixing time or more of the RH degassing vessel. The aluminum is added into the molten steel, and successively, it is detected whether or not 1 min or more after charging the aluminum is passed as the time when CO is stabilized during deoxidizing the molten steel with the aluminum. Successively, in the case of passing 1 min or more, CO concn. is measured at each 10 sec and in the case of raising CO cocn. after 20 sec from the some point of time to >=3%, the alarm sounds so that it is recognized that the stuck material is dropped.
|
