Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
248 words
A method for blowing gas from below into molten steel received in a refining vessel, which comprises: using a refining vessel including at least one gas blowing aperture provided in the bottom wall thereof and a frustoconical plug matching with said gas blowing aperture, releasably inserted into said gas blowing aperture from the outside of said bottom wall, which has a small-diameter bore having a diameter within the range of from 0.5 to 6.0 mm and a length within the range of from 60 to 700 mm; closing the top end of said small-diameter bore of said plug opening into said vessel with a granular packing which is removable by the pressure of the gas blown, thereby ensuring prevention, during receiving a molten steel into said vessel, of said received molten steel from penetrating into said small-diameter bore; blowing from below a gas having a pressure of over the static pressure of said molten steel through said small-diameter bore of said plug, after receiving said molten steel in said vessel, into said received molten steel, thereby instantaneously removing said granular packing to effect a prescribed gas blowing into said molten steel; and after discontinuing said gas blowing, causing a portion of said molten steel in said vessel to penetrate by gravity into said small-diameter bore of said plug to solidify the molten steel in said small-diameter bore, thereby closing said small-diameter bore to ensure prevention of said molten steel in said vessel from flowing out from said vessel.
Claim 2
Independent Claim
248 words
A method for blowing gas from below into molten steel received in a refining vessel, which comprises: using a refining vessel including at least one gas blowing aperture provided in the bottom wall thereof and a frustoconical plug matching with said gas blowing aperture, releasably inserted into said gas blowing aperture from the outside of said bottom wall, which has a small-diameter bore having a diameter within the range of from 0.5 to 6.0 mm and a length within the range of from 60 to 700 mm; closing the top end of said small-diameter bore of said plug opening into said vessel with a granular packing which is removable by the pressure of the gas blown, thereby ensuring prevention, during receiving a molten steel into said vessel, of said received molten steel from penetrating into said small-diameter bore; blowing from below a gas having a pressure of over the static pressure of said molten steel through said small-diameter bore of said plug, after receiving said molten steel in said vessel, into said received molten steel, thereby instantaneously removing said granular packing to effect a prescribed gas blowing into said molten steel; and after discontinuing said gas blowing, causing a portion of said molten steel in said vessel to penetrate by gravity into said small-diameter bore of said plug to solidify the molten steel in said small-diameter bore, thereby closing said small-diameter bore to ensure prevention of said molten steel in said vessel from flowing out from said vessel.
Claim 3
Dependent Claim
16 words
The method as claimed in claim 1, wherein said small-diameter bore comprises a small-diameter metal tube.
Claim 4
Dependent Claim
37 words
The method as claimed in claim 1, wherein: the periphery of said small-diameter bore is forcedly cooled by circulating cooling water in a helical cooling pipe provided around the periphery of said small-diameter bore in said plug.
Claim 5
Dependent Claim
46 words
The method as claimed in claim 2, wherein: the periphery of said small-diameter bore is forcedly cooled by circulating cooling air in a cooling air inner pipe and a cooling air outer pipe provided concentrically with said small-diameter metal tube as the center in said plug.
Claim 6
Independent Claim
67 words
The method as claimed in any of claims 1 to 4, wherein: a refining vessel is used, which includes at least two gas blowing apertures provided in the bottom wall thereof, and respective plugs each having said small-diameter bore, which are inserted respectively in said at least two gas blowing apertures; and, multiple-stage gas blowing including at least one interruption is effected by sequentially using said plugs.