US3333746A

US3333746A - Tundish ladles

Info

Publication number: US3333746A
Application number: US551369A
Authority: US
Inventors: Gerald R Cope; Charles R Hauth; Hyde Jack
Original assignee: Harbison Walker Refractories Co; Koppers Co Inc
Current assignee: Raymond Kaiser Engineers Inc; Harbison Walker Refractories Co
Priority date: 1966-05-19
Filing date: 1966-05-19
Publication date: 1967-08-01
Anticipated expiration: 1984-08-01

Description

TUND I SH LADLES Filed May 19, 1966 #WEA/MRS. GER/ILD R COPA?, .MC/f Al/DE United States Patent O 3,333,746 TUNDISH LADLES Gerald R. Cope, Johnstown, Charles R. Hauth, Bridgeville, and .lack Hyde, Pittsburgh, Pa., assignors of onehalf to Harbison-Walker Refractor-ies Company and one-half to Koppers Company, Inc., both of Pittsburgh,

Pa., both corporations of Pennsylvania Filed May 19, 1966, Ser. No. 551,369 7 Claims. (Cl. 222-566) ABSTRACT OF THE DISCLOSURE A tundish ladle of Vthe type used for continuous casting, which tundish is lined with refractory brick forming an inverted arch.

This invention relates to the continuous casting of steel More particularly, it relates to improvements in 4tundish construction for use in practicing various processes for the continuous casting of steel.

The commercial use of processes for the continuous casting of steels seems destined to take an increasingly important position in future steelmaking. Its many advantages in terms of cost, labor, and simplicity make it very attractive to an industry becoming highly automated.

The concept of continuous casting of steel is not new, however. As early as 1865, Sir Henry Bessemer envisioned the continuous casting of a steel plate or the like by continuously pouring molten metal between two water-cooled rollers to recover a strip of steel.

A recent article 1 is recommended for a detailed study and analysis of the evolution of processes for the continuous casting of steel from the early work of Bessemer lto many contemporary processes. As pointed out by the article, two of the more important and critical parts or steps in contemporary processes for the continuous casting of steel are considered to be:

(l) the actual pouring of a carefully regulated stream of molten metal into an initial freezing stage or mold, and,

(2) the actual cooling or freezing step itself.

In this latter step, a peripheral skin or shell is formed about a core of molten metal as it passes through the cooling stage or mold. This skin or shell formation must be carefully controlled if a breakout of molten metal is to be prevented. The eventual recovery of a billet of fairly uniform dimensions also depends on the skin formation. lf the stream of molten metal being poured-into the cooling or freezing stage is not constant in volume and cross sectional configuration, the formation of a uniform and suiciently strong skin is made diicult, if not impossible.

In many of the present practices, the semi-solidified stream is subjected to a pulling action by frictional engagement with driven rollers, or by frictional engagement with upwardly and downwardly reciprocating mold walls in the initial cooling stage. Of course, gravity itself can be of substantial effect in placing stresses on the evolving semi-solidified stream because of the substantially vertical process ow path present practices utilize.

Molten metal, often after some manner of degassing, for example, vacuum degassing, is fed to what is termed a tundish ladle. A nozzle for directing molten metal into the continuous casting machine opens from the lower portion of the tundish. A principal purpose of the tundish is to maintain a nearly uniform ferrostatic head above the nozzle. The nozzle and the tundish cooperate to control the flow rate, cross section, and turbulence of the stream 1 Leonard V. Gallagher et al., authors, Scientific American, December 1963.'

being fed to the cooling stage or mold. Obviously, they are a crucial part of the continuous casting apparatus.

Experience has shown that tundish ladles must be capable of holding a hot metal charge at a uniform temperature for a short period of time. Furthermore, they should be insulated so that sculling (solidification of the metal adjacent the lining) does not occur. To minimize the turbulence of the hot metal stream flowing from the ladle, the bottom of the tundish ladle adjacent the nozzle should be substantially flat and perpendicular to the center line of the nozzle.

The stream of hot metal is normally controlled by an operator who must actually observe the stream. Therefore, it is desirable that the tundish ladle be shaped so that the stream is easily observable.

Since .the tundish is so crucial in the continuous casting operation it is usually cooled between heats, cleaned and patched. The nozzle is replaced. After cleaning and repairing the interior of the ladle must be heated again before being charged with hot metal or a detrimental skull would form over the inner surface of the tundish ladle.

The ladle lining is, of course, periodically replaced. In most instances ladles are lined with as many standard brick shapes as possible and thereafter brick are cut and lit to the remaining spaces. This is a very laborious process. In some cases, special shapes are made to t nonuniform spaces; however, this is extremely costly.

It is an object of this invention to provide a tundish ladle which holds a hot metal charge at uniform temperatures for a limited period of time and delivers a stream having minimum turbulence to the continuous casting machine.

It is a further object of this invention to provide a tundish ladle shaped so that the hot metal stream is easily observable.

It is another object of this invention to provide tundish ladle which is easily cooled, cleaned, repaired and reheated.

It is still further another object of this invention to provide a tundish ladle which is lined with substantially all uniform brick shapes.

Briefly, according to one aspect of the present invention, there is provided a tundish ladle for use in the continuous casting process with an outer metal shell having two side walls, t'wo end walls and an arcuate bottom. It is preferred that the arcuate bottom is substantially tangent to the side walls. The side walls can, themselves, be arcuate and even be chords of the same arch forming the bottom. The metal shell is capable of supporting the tundish filled with metal. A refractory brick lining is .placed adjacent the outer shell. That portion of the brick lining adjacent the bottom and side walls is an inverted arch of one or more radii of curvature comprising brick of standard shapes, that is, straight, arch and perhaps wedge brick. There is at least one nozzle port opening Vthrough the brick and metal linings in which a refractory nozzle is inserted. A metal retaining rim is fastened to the edges of the end walls and side walls and cooperates with the arch to maintain the brick lining adjacent the metal shell when the ladle is rotated through 360 about an axis passing through the end walls of the ladle.

Further features and other objects and advantages of this invention will become apparent to those skilled in the art by careful study of the following detailed description with reference to the drawings in which:

FIG. l is a perspective view of a tundish ladle according to this invention; and,

FIG. 2 is an end view in section through a tundish ladle; and,

FIG. 3 is an end view in section through a tundish ladle at a pouring nozzle; and,

FIG. 4 is an alternate end view in section through a tundish ladle at a nozzle.

Referring now to the drawings, the tundish ladle according to this invention has an outer metal shell 1 which supports a refractory lining. Adjacent the metal shell there is preferably an insulating brick lining 3. The working lining 2 is adjacent the insulating lining. Preferably, in one embodiment, the working lining is composed of erosion resistant high alumina refractory brick.

The refractory lining adjacent the side walls and bottom is substantially an inverted arch. This is best Seen in FIG- URE 2. Both the insulating lining and the working lining are fabricated from standard refractory shapes. For a definition of the various standard refractory shapes the reader is referred to Modern Refractory Practices, 4th Edition, published by Harbison-Walker Refractories Cornpany, page 477 et seq. The combinations of brick required for the construction of the inverted arch depending on the size of the particular tundish are tabulated in the same reference at pages 536 et seq. It should be understood that arches may have more than one radius of curvature. Also, it is not necessary for the sections of an arch which have different radii of curvature to be tangent where they join. However, it is believed that the arch stability is increased if the two sections are substantially tangent.

The nozzle port 4 opens through the refractory lining and steel shell and the nozzle 7 is inserted therein. Space 6 surrounding the nozzle port may be brick of special shapes but is preferably fabricated from monolithic refractory materials. FIGS. 3 and 4 show two alternate constructions, both within the scope of this invention, which provide for a at area 8 surrounding the nozzle port which area is substantially perpendicular to the center line of the nozzle. Both FIGURES 3 and 4 show a preferred construction wherein the nozzle port is nearer to one side wall than another. However, a nozzle port centered at the bottom of the ladle would be acceptable. The curved bottom according to this invention, especially when the nozzle is placed closer to one side than another, greatly increases visibility of the stream.

A retaining rim is releasably attached, for example, by bolts or rivets, to the outer metal shell 1. The retaining rim can be L-shaped and positioned over the edges of the side walls and end walls to hold the refractory brick arch against the outer shell when it is rotated through 360 degrees.

The tundish ladle described above is superior to those provided by the prior art for several reasons. First, it can be lined completely with standard shapes without resorting to tedious cutting and fitting. This results in a substantial labor saving, but possibly more important, it reduces the rebuild time and therefore the total number of ladles needed in a continuous casting shop.

Y Tundish ladles according to this invention are more easily repaired as they can be rotated over on one side while workmen scrape awayv any slag or skull or loose lining and easily patch it with a monolithic refractory. The ladle can be completely inverted for knocking out the old nozzle and then uprighted for placing a new nozzle, which is generally held in place by refractory mortar. For reheating the ladle prior to charging, it can again be inverted thereby removing the requirement for a temporary ladle cover.

Having thus ldescribed the invention in detail and with suliicient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

We claim:

1. In an open-topped, bottom-pouring tundish of the type used in continuous casting of molten metal, the tundish having two upright end walls, two side walls, and an elongate arcuate bottom and comprised of an outer metal shell and an internal refractory lining, said tundish capable of containing and defining an easily observable stream of molten metal owing from input to a discharge through the bottom of said tundish spaced from said input, the discharge being defined by at least one refractory nozzle opening through the arcuate bottom of said tundish, the improvement comprising a bottom and at least two opposed sides joining the bottom being fabricated of a plurality of separate refractory brick together keyed to form an inverted refractory arch as the refractory lining of said tundish which is arranged to contain said observable stream of molten metal, and means cooperating with the outer metal shell and said refractory brick to hold said brick in position when said tundish is inverted.

2. A tundish ladle according to claim 1 in which said arch is comprised of standard straight arch and wedge brick shapes.

3. A tundish ladle according to claim \1 in which the brick lining comprises two layers, one layer being adjacent the metal shell consisting of insulating brick and the other layer being a working layer lining comprising an erosion resistant high alumina refractory brick.

4. A tundish ladle according to claim 1 in which said discharge is closer to one side than the other.

5. A tundish ladle according to claim 1 in which said discharge is lined with a monolithic refractory material shaped in place to accommodate a refractory nozzle.

.6. A tundish ladle according lto claim 1 in which the inner surface surrounding the ladle port is substantially at and perpendicular to the center line of said discharge.

7. A tundish ladle according to claim 1 in which the side walls and arcuate bottom are substantially tangent.

References Cited UNITED STATES PATENTS 117,918 8/ 1871 Ostrander 22-84 521,519 6/1894 Adams 22-85 1,889,426 11/1932 Stout 266-39 2,113,894 4/ 1938 Lucier 22-85 2,182,675 12/1939 Morton 266-38 2,230,141 1/1941 Heuer 266--43 2,836,793 3/ 1958 Flickinner et al. 22-85 2,897,555 8/ 1959 Nishikiori 22--79 3,203,689 8/ 1965 Hallowell 22-84 I. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner.

Claims

1. IN AN OPEN-TOPPED, BOTTOM-POURING TUNDISH OF THE TYPE USED IN CONTINUOUS CASTING OF MOLTEN METAL, THE TUNDISH HAVING TWO UPRIGHT END WALLS, TWO SIDE WALLS, AND AN ELONGATE ARCUATE BOTTOM AND COMPRISED OF AN OUTER METAL SHELL AND AN INTERNAL REFRACTORY LINING, SAID TUNDISH CAPABLE OF CONTAINING AND DEFINING AN EASILY OBSERVABLE STREAM OF MOLTEN METAL FLOWING FROM INPUT TO A DISCHARGE THROUGH THE BOTTOM OF SAID TUNDISH SPACED FROM SAID INPUT, THE DISCHARGE BEING DEFINED BY AT LEAST ONE REFRACTORY NOZZLE OPENING THROUGH THE ARCUATE BOTTOM OF SAID TUNDISH, THE IMPROVEMENT COMPRISING A BOTTOM AND AT LEAST TWO OPPOSED SIDES JOINING THE BOTTOM BEING FABRICATED OF A PLURALITY OF SEPARATE REFRACTORY BRICK TOGETHER KEYED TO FORM AN INVERTED REFRACTORY ARCH AS THE REFRACTORY LINING OF SAID TUNDISH WHICH IS ARRANGED TO CONTAIN SAID OBSERVABLE STREAM OF MOLTEN METAL, AND MEANS COOPERATING WITH THE OUTER METAL SHELL AND SAID REFRACTORY BRICK TO HOLD SAID BRICK IN POSITION WHEN SAID TUNDISH IS INVERTED.