Method of treating metal melts with a purging gas during the process of continuous casting

• US 3,886,992 A
• Filed: 05/26/1972
• Issued: 06/03/1975
• Est. Priority Date: 05/28/1971
• Status: Expired due to Term

• Current Assignee: Thyssen Industrie AG (Thyssenkrupp AG)
• Original Assignee: Claus Raeune, Hermann Maas, Horst Abratis
• Inventors: Maas, Hermann, Abratis, Horst, Raeune, Claus
• Primary Examiner(s): Annear, R. Spencer
• Application Number:
  US05/257,421
• Time in Patent Office: 1,103 Days
• Field of Search: 164/55,56,66,82,259,266,281 222/DIG.11,DIG.21 266/38
• US Class Current: 164/473
• CPC Class Codes: B22D 11/11 Treating the molten metal
• CPC Class Codes: C21C 7/0043 into the falling stream of molten metal
• CPC Class Codes: C21C 7/0068 by introducing material into a current of streaming metal
• CPC Class Codes: C22B 9/05 Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ

Abstract

A method of, and apparatus for, treating metal melts during continuous casting, wherein the teeming metal is enclosed to a point below the surface of the metal pool in the continuous casting mold to avoid contact with the ambient atmosphere and the surface of the pool is covered with a layer of slag. Small volumes of purging gas are introduced in bubble form into the metal melt at the location where such metal melt begins to form a teeming jet.

Claims

1. A method of treating metal melts during continuous casting for suppressing the formation of undesirable oxidic non-metallic inclusions, comprising the steps of enclosing the teeming metal to a point below the surface of the metal pool in a continuous casting mold to avoid contact with the ambient atmosphere, covering the surface of the pool with a layer of slag, and introducing small volumes of purging gas in bubble form into the metal melt at the location where such metal melt begins to form a teeming jet, so that the injector-like action of the melt divides the gas into a multiplicity of very small bubbles which are carried into the mold by the melt.

2. The method as defined in claim 1, including the step of introducing deoxidants and alloying elements together with the purging gas into the metal melt at the location where such metal melt begins to form a teeming jet.

3. The method as defined in claim 2, wherein the deoxidants and alloying elements are introduced continuously at a rate corresponding to the casting rate.

4. The method as defined in claim 2, wherein the deoxidants and the alloying elements are added at a rate which progressively increases as casting continues.

6. The method as defined in claim 1, including the step of introducing at least alloying elements together with the purging gas into the metal melt at the location where such metal melt begins to form a teeming jet.

7. The method as defined in claim 6, wherein the alloying elements are introduced continuously at a rate corresponding to the casting rate.

8. The method as defined in claim 6, wherein the alloying elements are introduced at a rate which progressively increases as casting continues.

9. The method as defined in claim 1, including the step of introducing deoxidants together with the purging gas into the metal melt at the location where such metal melt begins to form a teeming jet.

10. The method as defined in claim 9, wherein the deoxidants are introduced continuously at a rate corresponding to the casting rate.

5. A method of treating metal melts during continuous casting in order to reduce the formation of undesirable oxidic accumulations, comprising the steps of confining the teeming metal so as to avoid contact with the ambient atmosphere to a location below the surface of the metal pool in a continuous casting mold, and introducing small volumes of purging gas in bubble form into the metal melt approximately at the location where the metal melt begins to form a teeming jet, so that the injector-like action of the melt divides the gas into a multiplicity of very small bubbles which are carried into the mold by the melt.