PLASMA TORCH FOR HEATING MOLTEN STEEL IN TUNDISH

摘要

PROBLEM TO BE SOLVED: To keep plasma arc stable without affected by argon atmosphere in a heating chamber, i.e., affected by the closeness in the heating chamber, in a plasma torch for heating molten steel in a tundish. SOLUTION: The plasma torch 1 for heating the molten steel in the tundish is provided with a cathode 7 in the inner part and a nozzle 9 at the outer periphery thereof as the same way as the conventional technique, and the gaseous argon is made to flow as working gas 10 for plasma between the cathode 7 and the nozzle 9 so as to spout the gaseous argon from the tip part of the torch. The working gas 10 is formed as the plasma and the plasma arc 6 is generated between an electrode 8 fitted to the tip part of the cathode 1 and the molten steel 3. A seal gas supplying tube 4 is further arranged at the outer periphery of this nozzle 9 and the gaseous argon is supplied into the tip part of the plasma torch as the seal gas 5 between the nozzle 9 and the seal gas supplying tube 4 and the gaseous argon is spouted from the tip part thereof to seal the plasma arc 6.