| 摘要 |
PURPOSE:To check opening degree of tuyere aperture to always maintain the fixed degree and to prevent tuyere clogging, by connecting an oxygen supplying pipe and a gas supplying pipe for checking tuyere opening degree to a flux supplying pipe of an RH type vacuum degassing vessel. CONSTITUTION:The tuyere 5 is provided lower than molten steel level in the RH vacuum degassing vessel 1 and connected to a flux supplying pipe 6, the oxygen supplying pipe 10 and a supplying pipe 12 of a tuyere opening ratio checking gas 11 through cut-off valves 13, 14, 15 respectively. Preliminary refining is performed together with degassing refining by supplying flux for refining such as desulfurization, dephosphorization of molten steel from a tuyere 5 by a carrier gas 8. In this case, previously the valves 13, 14 are closed and the valve 15 is opened, and gas for checking tuyere opening ratio is supplied to the tuyere 5. If opening ratio is decreased by solidification and sticking of metal at the tuyere 5, since pressure at tuyere is raised, the value is measured by a pressure gauge 16, if the value is attained to >= a fixed value, the valve 15 is closed, 14 is opened to supply oxygen to the tuyere 5. Metal stuck to tuyere is melted and removed to raise opening ratio of tuyere to a prescribed value. |
