VACUUM DEGASSING DEVICE

PURPOSE:To prevent the decrease in the life of a plasma torch and to prevent sticking of splash by the organic combination of a plasma arc heater for the molten steel in a ladle and a vacuum degassing device. CONSTITUTION:A vacuum degassing device 3 and a plasma arc heater 4 for the molten steel 2 in a ladle 1 are installed in combination in a ladle 1. The device 3 is constituted mainly of a degassing vessel 5, a riser 5, a reflux gas blowing pipe 7, a downcomer 8 and an evacuating system 9. On the other hand, the heater 4 is constituted of a heating chamber 10, an electrode 11 for generating plasma arc and a working gas supplying pipe 12. The heater 14 uses the electrode 11 as cathode and the conductive refractory wall 13 formed on the inside surface of the vessel 5 as a power feed electrode. The molten steel 2 in the ladle 1 is made anode via the molten steel 2' under vacuum degassing treatment by said electrodes. The bottom end position of the wall 13 is immersed in the molten steel 2' and the top end position is made the max. scattering height of splash. Since the wall 13 attains a high temp., the formation of a base metal by sticking of the splash thereon is obviated.