| 摘要 |
<p>The invention provides a method for refining molten steel by immersing
the lower opening end of a cylindrical immersion tube equipped with a lance into the molten steel contained in a ladle, controlling the pressure in the cylindrical immersion tube to a prescribed pressure range to suck up the molten steel, injecting an agitation gas from the bottom of the ladle towards the surface of the sucked-up molten steel, and dephosphorizing and refining the molten steel under a reduced pressure, characterized in that the method comprising the steps of;
controlling the pressure in the cylindrical immersion tube to the range of 100 to 500 Torr,
controlling the injection amount of the agitation gas to the range of 0.6 to 3.0 Nl/min.·t,
controlling free oxygen in the molten steel to 300 ppm or more,
blowing a dephosphorizing agent in powder form, together with a carrier gas, through the lance to the molten steel surface, and
dephosphorizing and refining the molten steel under a reduced pressure.</p> |
