METHOD FOR ADDING EASILY VAPORIZING ALLOY INTO RH DEGASSING VESSEL

PROBLEM TO BE SOLVED: To add an easily vaporizing alloy in good yield and to effectly float up and separate produced inclusion under sufficient stirring by forming the easily vaporizing alloy as wire-state and supplying this alloy into molten steel through a top-blown lance. SOLUTION: The easily vaporizing wire 6, such as CaSi, is introduced into a circulating chamber 4 of an RH gas vessel from the upper end part of the top-blown lance 5 while passing in the top-blown lance 5 through a seal part 7. At this time, supplying speed of the wire 6 is desirable to be >=40 m/min. This lower limit speed is calculated from melting speed of the wire 6 in the molten steel and in the case of being less than this speed, this alloy is vaporized before promoting the melting in the steel and the remarkably lowering of the yield is brought about. Further, since the charging of the alloy wire 6 to the center part in the vessel, i.e., the central part of the molten steel fluid by using the top-blown lance 5 as the introducing tube, can be executed, the stirring of Ca can efficiently be executed.