Leak-Proof Upper Tundish Nozzle

Abstract

A leak-proof gas injected upper tundish nozzle including a protective can, and a ceramic inner portion disposed within the protective can. The ceramic inner portion may has gas flow pathways therein which have been formed using a sacrificial mold when producing the ceramic inner portion. A gas flow seal is formed on the interior surfaces of the gas flow pathways within the ceramic inner portion. The gas flow seal blocks gas leakage from the gas flow pathways into any cracks in the ceramic inner portion. The gas flow seal is formed of nickel or an alloy of nickel.

Claims

1-10. (canceled)

11. A gas injected upper tundish nozzle, the nozzle comprising: a protective can; a ceramic inner portion disposed within the protective can, the ceramic inner portion having gas flow pathways therein, the gas flow pathways having been formed using a sacrificial mold when producing said ceramic inner portion; a gas injection port attached to the protective can, the gas injection port allowing for injection of gas through the protective can and into the gas flow pathways within the ceramic inner portion; a gas flow seal formed on interior surfaces of the gas flow pathways within sthe ceramic inner portion, the gas flow seal blocking gas leakage from the gas flow pathways into any cracks in the ceramic inner portion; the gas flow seal being formed of nickel or an alloy of nickel.

12. The gas injected upper tundish nozzle as recited in claim 11 wherein the gas flow passages include a gas pressure/distribution manifold and individual gas injection channels.

13. The gas injected upper tundish nozzle as recited in claim 12 wherein the sacrificial mold includes a proto-manifold and proto-injection channels formed of sacrificial material.

14. The gas injected upper tundish nozzle as recited in claim 13 wherein the gas flow seal is formed by depositing nickel or nickel alloy onto the proto-manifold and proto-injection channels by a method selected from the group consisting of electroless plating, nickel foil strip application, sputtering, physical vapor deposition, chemical vapor deposition, plasma deposition, and metal printing.

15. The gas injected upper tundish nozzle as recited in claim 14 wherein additional nickel or nickel alloy is deposited into the gas pressure/distribution manifold and individual gas injection channels after the sacrificial mold has been removed from said ceramic inner portion.

16. The gas injected upper tundish nozzle as recited in claim 11 wherein the protective can is formed of a metal material.

17. The gas injected upper tundish nozzle as recited in claim 16 wherein the protective can is formed of a steel material.

18. The gas injected upper tundish nozzle as recited in claim 11 wherein the ceramic inner portion is formed from a refractory material consisting of a ceramic oxide of one or more of aluminum, silicon, magnesium, chromium, or zirconium, or mixtures thereof.

19. The gas injected upper tundish nozzle as recited in claim 11 wherein the gas distribution channels have gas outlets to release the gas into steel flowing within the upper tundish nozzle.

20. The gas injected upper tundish nozzle as recited in claim 12 wherein the gas flow seal is formed by depositing nickel or nickel alloy into said gas pressure/distribution manifold and individual gas injection channels after the sacrificial mold has been removed from the ceramic inner portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 depicts a cross section of such a continuous casting line in which the upper tundish nozzle of the present is preferably used;

[0016] FIG. 2 is a closer view of the tundish and the casting mold and specifically shows the position of the upper tundish nozzle;

[0017] FIG. 3 is a simplified cross section of an upper tundish nozzle;

[0018] FIG. 4A is a cross-sectional view of a sacrificial mold 6* useful for the present invention;

[0019] FIG. 4B is a 3D depiction of a sacrificial mold 6* useful for the present invention;

[0020] FIG. 4C is a cross-sectional depiction of a sacrificial mold 6* onto which a nickel or nickel alloy sealant layer 11 has been deposited;

[0021] FIG. 5 depicts a cross-sectional depiction of an upper tundish nozzle 4 including the inventive sealing solution.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention is an improved argon injected upper tundish nozzle 4 which minimizes/eliminates unwanted leakage of inert gas (such as argon) therefrom.

[0023] The upper tundish nozzle 4 of the present invention is the type that contains preformed argon pressure/distribution manifold 8 and individual gas injection channels 8 as shown in FIG. 3. The preformed argon pressure/distribution manifold 8 and individual gas injection channels 8 are formed within the ceramic inner portion 6 during manufacture of said upper tundish nozzle 4.

[0024] The ceramic inner portion 6 of the upper tundish nozzle 4 is generally formed by hydrostatic pressing of powdered ceramic materials. For this type of upper tundish nozzle 4, the preformed argon pressure/distribution manifold 8 and individual gas injection channels 8 are formed by isostatic pressing of the powdered ceramic material around a sacrificial mold. After the isostatic pressing, the mold is then removed leaving the argon pressure/distribution manifold 8 and individual gas injection channels 8.

[0025] FIG. 4A is a cross-section of such a sacrificial mold 6* and FIG. 4B is a 3D depiction thereof. The mold 6* contains the design for the argon flow system including the proto-manifold 8* and the proto-injection channels 8**. FIG. 4C is a cross-sectional depiction of the sacrificial mold 6* onto which a nickel or nickel alloy sealant layer 11 has been deposited onto the surface of the proto-manifold 8* and proto-injection channels 8** portions thereof.

[0026] FIG. 5 depicts a cross-section of the upper tundish nozzle of present invention specifically showing the nickel or nickel alloy sealant layer 11 as it remains on the inner surfaces of the preformed argon pressure/distribution manifold 8 and individual gas injection channels 8 after the sacrificial mold 6* has been removed. The nickel or nickel alloy sealant layer 11 helps to reduce or eliminate the loss of argon from the upper tundish nozzle 4 through cracks and/or pores within the inner ceramic portion 6 thereof. It is believed that this seal 11 remains ductile at the elevated temperatures which helps to prevent cracks from leaking.

[0027] The inventors electroplated nickel onto a sacrificial mold 6* and used it to isostatically press to form an upper tundish nozzle 4. While the inventors have used electroplating to deposit the nickel seal 11. Other viable techniques include electroless plating, nickel foil strips, sputtering, physical vapor deposition, chemical vapor deposition, plasma deposition, metal printing and the like. What is important is not how the nickel got into position, but rather forming the nickel seal 11 onto the inner surface of the argon pressure/distribution manifold 8 and individual gas injection channels 8 of the ceramic inner portion 6.

[0028] Further, while the nickel sealant layer 11 may be formed onto the sacrificial mold 6*, it may alternatively be formed by gaseous or liquid deposition onto the inner surface of the argon pressure/distribution manifold 8 and individual gas injection channels 8 after the ceramic inner portion 6 has already been formed. Additionally, both pre-production deposition of the nickel/alloy sealant 11 onto the sacrificial mold 6* and post-production of deposition of additional nickel/alloy sealant 11 may be combined to form the final product.