Method of making ultra-low carbon and sulfur steel
AssigneeLTV Steel Company, Inc.
InventorKevin C. Ahlborg
Life of this patent
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Abstract
A method of making ultra-low carbon, ultra-low sulfur content steel comprising introducing molten metal and slag into a vacuum decarburizer to reduce the carbon content of the metal to below 0.005%, followed by deoxidizing the molten steel, deoxidizing the slag and mixing the slag with the molten steel to reduce the sulfur content to below 0.005%.
Claims22
A method of making ultra-low carbon, ultra-low sulfur content steel from a charge comprising a quantity of molten ferrous metal, which contains carbon, sulfur and oxygen, and slag, said method comprising:
- a) introducing said molten metal and slag into a low pressure environment to reduce the carbon content of the metal;
- b) deoxidizing said molten metal;
- c) deoxidizing said slag;
- and,
- d) mixing said deoxidized slag with said deoxidized molten metal to reduce the sulfur content of said molten metal.
A method of making ultra-low carbon, ultra-low sulfur content steel from a charge comprising a quantity of molten ferrous metal, which contains carbon, sulfur and oxygen, and slag, said method comprising:
- a) introducing said molten metal and said slag into a low pressure environment and maintaining said molten metal and said slag in the low pressure environment at least until the carbon content of the metal is reduced to below about 0.005% by weight based on the weight of the molten metal;
- b) deoxidizing said molten metal;
- c) deoxidizing said slag;
- and,
- d) mixing said deoxidized slag with said deoxidized molten metal until the sulfur content of said deoxidized molten metal is below about 0.005% by weight based on the weight of said deoxidized molten metal.
A method of making ultra-low carbon, ultra-low sulfur content steel from a charge comprising a quantity of molten ferrous metal, which contains carbon, sulfur, and oxygen, and slag, said method comprising:
- a) introducing said molten metal and slag into a low pressure environment to reduce the carbon content of the metal;
- b) deoxidizing said molten metal;
- c) deoxidizing said slag;
- and
- d) after the carbon content of the metal has been reduced, mixing said deoxidized slag with said deoxidized molten metal to reduce the sulfur content of said deoxidized molten metal.
Dependencies are inferred from the claim text.