| 摘要 |
PURPOSE:To obtain economical molten steel with low oxygen and high nitrogen without variation of components other than nitrogen by using nitrogen for lifting gas or mixing gas to increase the partial pressure of nitrogen. CONSTITUTION:After applying dehydrogenation and deoxydation sufficiently to molten steel at the high degree of vacuum, the exhaust capacity of the vacuum pump is reduced and nitrogen is continued to be sent while decreasing the opening of valve B. When argon gas has been used, nitrogen gas is sent instead of argon to make the inside of the vacuum case nitrogen gas atmosphere. At the time, the molten steel is violently agitated and contacted with nitrogen gas. Thus, a required volume of nitrogen can be added into the molten steel at the speed corresponding to the partial pressure of nitrogen and the composition of molten steel. After adding nitrogen to the molten steel, the vacuum gas separating case is opened and the ladle is sent to an ingot making plant. |
