Liquid Air Corporation

L'air Liquide

Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges

Sara H Anderson

Jean Foulard

Curtis L Bermel

Noel F Lutgen

Jocelyne McGeever

Casey McGeever

Daniel R Urban

Greg Carr

In a method for decarburizing metals and alloys, a two-gas component mixture consisting only of oxygen and carbon dioxide is introduced into molten metals or alloys at least during the first decarburization phase.

Replacement of argon with carbon dioxide in a reactor containing molten

The present invention relates to a process for producing steel in a ladle furnace in which the molten steel is stirred by injection of an inert gas in the lower part of the furnace. According to the invention, the stirring of the bath of steel is effected by the injection of gaseous argon so as to distribute in a homogeneous manner the additives added and the metal temperature in the course of the treatment, while there is simultaneously injected liquid argon above the surface of the bath in the region of intumescence. In this way, substantially any increase in the concentration of nitrogen of the bath of steel in the course of the treatment is avoided. In some cases, and in particular when wires of the type filled with silico-calcium are employed, a reduction in the concentration of nitrogen in the bath of steel is found.

Process for producing steel having a low content of nitrogen in a ladle

Inert liquid gas such as liquid nitrogen or liquid argon is used in vertical melting furnaces to prevent oxidation of the metal during holding periods. The method can be applied to any kind of metal. The use of inert liquid gas for the 'blow-dow' of the furnace will flush art all existing furnace atmosphere and prevent oxidation. The casting recovery time may be reduced from about one hour to 15 minutes. Also the layers of oxide resulting from oxidation can be negated, allowing for fewer rejects, if any, during further surface treatment.

Method to protect the surface of metal in vertical melting furnaces

Liquid argon, nitrogen or carbon dioxide is poured onto the surface of a bath of molten metal in a furnace. According to the invention, liquefied gas is discharged onto the surface in an amount which ranges from about 0.025 to 0.060 lb/cu. in. of metal in the furnace, while a skirt is preferably set around the open end of said furnace. Oxygen concentration above the bath remains lower than about 3.0%, while hydrogen and nitrogen pick up are reduced.

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Westmont, IL, United States of America

Sara H Anderson