PURPOSE: To accelerate decarburization effectively during degassing treatment by controlling the flow rate of a blowing gas for reflux to be supplied to riser pipes at the rate exceeding the saturation range of the reflux rate of molten steel without changing the existing RH degassing device.
CONSTITUTION: With plural immersion pipes 2 opening under the surface of molten steel and a vacuum vessel communicating with these pipes 2, a gas inert to molten steel, for example, gaseous Ar is supplied at 1.8W3.2Nl/min, cm3 one ≥1 pipe 2 out of the pipes 2 to conduct the ascending flow of the molten steel in the vacuum vessel. At the same time, the descending flow from the vacuum vessel is conducted through the remaining pipes 2 to degas the molten steel continuously under the reflux of the molten steel in the vacuum vessel. More specifically, the blowing rate of said gaseous Ar is controlled to the rate exceeding the saturation region of the reflux rate of the molten steel in the vacuum vessel, whereby the decarburization reaction at the foam surface in the ascending flow of the molsten steel is accelerated.
UEDA ARATA
HINA EIJI
| JPS525614A | 1977-01-17 | |||
| JPS54118318A | 1979-09-13 |