Metallurgical apparatus – Process
Reexamination Certificate
2003-12-02
2004-09-07
Kastler, Scott (Department: 1742)
Metallurgical apparatus
Process
C266S275000, C266S286000
Reexamination Certificate
active
06787098
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to refractory linings for metallurgical vessels, and more particularly to a lining bottom for such vessels. The invention is particularly applicable for use in ladles used in handling molten steel, and will be described with particular reference thereto. It will, of course, be appreciated that the present invention has application in other types of metallurgical vessels for handling molten metal.
BACKGROUND OF THE INVENTION
The handling of high-temperature liquids, such as molten steel, requires special materials and techniques. Ladles used for handling molten steel are comprised of an outer metallic shell that is lined with a refractory material. The inner surface of the metallic shell is typically lined with one or more layers of a refractory brick that can withstand extremely high temperatures and harsh, abrasive conditions. Such brick eventually wears from repeated use of the ladle, thus requiring its repair or replacement. One mechanism causing wear of the refractory lining is the impact forces exerted on the lining when high temperature liquids are poured into the ladle. These “stream impact” forces tend to significantly increase erosion in certain portions of the bottom lining of the ladle.
In order to balance wear of the refractory lining and steel ladle, it is known to use thicker bricks in the area of steel stream impact. As will be appreciated, the lining of ladles with brick is both time-consuming and labor intensive. Castable refractory materials that can withstand the high temperatures of molten steel are known, but many of these refractory materials quickly wear in the area of steel stream impact. Some castable materials can withstand both high temperatures and have good corrosion properties, but such materials are typically relatively expensive and less cost efficient.
The present invention overcomes these and other problems and provides a refractory assembly for lining the bottom of a metallurgical vessel, such assembly having an impact area comprised of high-density, high-temperature bricks.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a lining for the bottom of a metallurgical vessel comprising an impact pad comprised of a plurality of close-packed, pre-formed refractory bricks. The pad has an upper impact surface. A monolithic slab of a high-temperature refractory material encases the pad. The slab encases the pad such that the upper surface of the impact pad is exposed.
In accordance with another aspect of the present invention, there is provided a bottom lining in a metallurgical vessel that is used for receiving and dispensing a molten metal. The lining is comprised of an impact pad comprised of a plurality of close-packed, pre-formed refractory bricks. The pad has an upper impact surface. A monolithic slab of a high-temperature refractory material encases the pad. The slab encases the pad such that the upper surface of the impact pad is exposed.
In accordance with another aspect of the present invention, there is provided a method of forming a refractory lining for the bottom of a metallurgical vessel, comprising the steps of:
(a) forming an impact pad by assembling a plurality of pre-formed, high-density, high-temperature refractory bricks into a close-packed arrangement, the pad having an upper impact surface;
(b) pouring a high-temperature refractory material into a cavity around the pad; and
(c) curing the refractory material to form a monolithic slab encasing the pad with the upper impact surface of the pad exposed.
It is an object of the present invention to provide a refractory lining for the bottom of a metallurgical vessel.
It is another object of the present invention to provide a lining as described above that includes a high-temperature resistant, high-density impact area on which incoming molten metal may impinge.
It is another object of the present invention to provide a lining as described above wherein a portion of said lining is a cast refractory.
A still further object of the present invention is to provide a lining as described above wherein a major portion of the lining is a cast refractory.
A still further object of the present invention is to provide a lining as described above that may be preformed for insertion into a metallurgical vessel.
A still further object of the present invention is to provide a method of forming a lining for the bottom of a metallurgical vessel as described above.
A still further object of the present invention is to decrease ladle down time and the cost associated with the replacement of a lining for a metallurgical vessel.
These and other objects and advantages will become apparent from the following description of a preferred embodiment in the present invention taken together with the accompanying drawings and the appended claims.
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Derwent Document No. 1995-358956, Nov. 1994, 2 pages.
Derwent Document No. 1995-358957, Nov. 1994, 2 pages.
Abrino Donald E.
Barrett Ronald
Crooks John
Miglani Shyam
Kastler Scott
Kusner & Jaffe
North American Refractories Co.
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