US3382913A - Apparatus for uninterrupted continuous casting - Google Patents

Description

Filed Aug. 25, 1965 2 Sheets-Sheet 1 N l INVENTOR. ANATOL MICHELSON 7 5 & BY

ATTORNEYS May 14, 1968 A. MICHELSON 3,382,913

APPARATUS FOR UNINTERRUPTED CONTINUOUS CASTING Filed Aug. 25, 1965 2 Sheets-Sheet 2 INVENTOR. ANATOL MBCHELSON ATTORN EYS United States Patent 3,382,913 APPARATUS FOR UNINTERRUPTED CONTINUOUS CASTENG Anato! Michelson, Glenolden, Pa, assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Aug. 25, 1965, Ser. No. 482,360 5 Claims. (Cl. 164281) ABSTRACT OF THE DESULOSURE This disclosure pertains to the art of continuous casting and more particularly to apparatus for supplying molten metal to a casting mold without interruption. In the disclosure a pair of tundishes is adapted to contain a quantity of molten metal to be cast. Each tundish is movable along a common line of movement intercepting the mold. The line of movement extends from a pouring location above the mold in opposite directions to idle positions on either side thereof. As one tundish is in the pouring location supplying metal to the rnold, the other, a full one, is in an idle position alongside. An open trough extends outwardly from the mold axis along the line of movement above the mold. The trough is inclined toward the mold so as to direct the flow of metal into the mold. During the transition movement of the tundishes, the full for the empty between the idle and pouring positions, the molten metal is conducted to the mold from the full tundish by the trough until such time as its location coincides with the pouring position vacated by the empty tundish. The disclosure further contemplates a trough extending outwardly in opposite directions on each side of the mold so that pouring may commence from either tundish from the idle position. Also, either or both troughs may be pivoted adjacent the mold so that its outer end can be tilted below the top of the mold or extended laterally to interrupt flow to the mold so as to discard metal from either tundish when desired.

The invention will be described with particular reference to a method and apparatus for pouring molten ferrous metals such as steel into a continuous casting mold, however, it should be appreciated that it has much broader applications and is equally applicable to the gravity feeding of other liquid substances where the procedure is to hold the liquids in reserve in batch form until intended for use and then to sequentially feed individual batches without interruption of flow.

In continuous casting installations ladles of molten metal are usually not poured directly into the mold. Instead they are tapped into an intermediate vessel referred to in the trade as a tundish located between the ladle and the mold. From the tundish, molten metal is metered into the top of the mold at a rate approximately equal to the rate an ingot is withdrawn from the bottom.

In the casting of ferrous metals such as steel for example, the combination of a high casting temperature, chemical attack and physical erosion on the refractory parts of the ladles and tundish permit a continuous run of only about one hour before the casting cycle is interrupted. The interruption occurs mainly because the nozzle and stopper head of the tundish must be replaced. Their service life usually does not exceed 60 minutes with existing refractory materials. This short service life causes interruptions in the continuous casting process which consumes about 50 percent of the available time.

The present invention contemplates a method and apparatus for overcoming this problem by permitting an interval during the casting cycle in which the ladle and tundish may undergo repairs without interrupting casting operations.

In accordance with the broadest aspect of the invention, the method proceeds by metering a stream of liquid at a fixed pouring location from a substantially full container and associated intermediate vessel, shifting the container and vessel together relative to the pouring location before they become empty, conducting the liquid stream to the previous pouring location by gravity flow means and starting a metered flow of liquid from another full container and intermediate vessel shortly before flow diminishes from the first container and vessel so as to supplement the diminishing liquid stream therefrom, whereby the total metered flow requirements are maintained while the first container and intermediate vessel are al lowed to become empty.

More particularly, where the liquid is a molten metal and the containers and intermediate vessels are refractory lined ladles and tundishes and the pouring location is a continuous casting mold, the arrangement is such that one ladle and tundish is in a discharge position directly supplying the mold while the other is in an idle position alongside and the ladles and tundishes are supported for movement relative to the mold so as to be shifted in 1 tandem back and forth above the mold.

Further in accordance with the invention, in combination with the tundishes is an apparatus for conducting the liquid stream of molten metal to the mold by gravity flow means which includes refractory trough members mounted between the mold and tundishes and extending outwardly in alignment with the path of movement of the tundishes, the trough members being inclined so that their lower ends are at the pouring location over the mold while their upper ends extend beneath one or both of the tundishes.

Further in accordance with the invention, the trough members include two inclined trough sections each of which extends from adjacent the mold outwardly in opposite directions along the line of movement of the tundishes, the inner adjacent ends of each section having a mating cutout portion to define a circular pouring opening aligned with the pouring location of the mold.

Where it is desirable to divert a portion of the metered flow entirely away from the mold, a trough section is pivotally mounted adjacent the mold so that its outer end can be tilted below the top of the mold.

It is also desirable to conduct metal through the trough members when a fresh ladle and tundish are initially tapped to carry away refractory debris which may be present and therefore in addition to being pivotally mounted, the trough sections are mounted on trackways so as to be movable rectilinearly beneath the pouring location.

The principal object of the invention is to provide a method and apparatus for continuously feeding a metered stream of liquid from a liquid source that is constituted as a plurality of separate containers.

Another object is to provide a new and improved method for feeding a continuous casting mold whereby part of the refractory pouring apparatus is idle while another part is supplying the mold and the parts alternate positions so as to permit replacement .and repair Without halting the casting cycle.

These and other objects will be more fully appreciated by referring to the following description and drawings wherein:

FIGURE 1 is a partial sectional view showing a tandem tundish and ladle arrangement as embodied in the invention and as applied to the pouring of a continuous casting mold;

FIGURE 2 is a plan view taken along line 2-2 of FIGURE 1 showing the principal pouring position of the apparatus in FIGURE 1;

FIGURE 3 is a cross-sectional view of a portion of La the apparatus in FIGURE 1 taken along line 3-3 of FIGURE 4 showing a trough member used to feed the mold during the transition of the apparatus between pouring positions;

FIGURE 4 is a side view of the trough member;

FIGURE 5 is a schematic view depicting the relative pouring positions of the apparatus when one tundish is supplying the full mold requirements;

FIGURE 6 is a schematic view similar to FIGURE 5 depicting the relative positions when the apparatus is shifted in accordance with the invention; and

FIGURE 7 is a view which illustrates the position of the apparatus when a portion or the entire flow to the mold is to be diverted.

Referring to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, FIGURE 1 shows the upper portion only of a continuous casting installation 10 utilizing standard bottom pour ladles 11, 11 to supply molten metal to a conventional water cooled continuous casting mold 12. While not shown, it will be appreciated that the casting installation It extends vertically below the mold 12 and would include the usual guide rolls, pulling mechanism, cooling apparatus, and cutting equipment for handling the cast ingot being withdrawn from the bottom of the mold 12.

The ladles 11, 11 are held in separate pouring sections 14, 14 each of which is movable along rails 17 supported on stanchions 18 above the mold 12. Preferably the pouring sections are connected together for movement in unison, however they may be separated if desired and their movements correlated. Since the sections 14, 14 are substantially the same in construction a description with respect to one will be understood as applying equally to the other and like parts will be identified by like numerals with the addition of a prime mark. With respect to the pouring section 14, on the left as viewed in FIGURE 1, a carriage 15 is provided having bogies 16 guided on rails 17 for movement toward and away from the mold 12. The carriage 15 has an upper platform 20 adapted to support the ladle 11 in a bottom dropped position. The ladles are of the off-center pour type. A tundish 24 is postiioned below ladle nozzle 28 and is supported on a hanger 26 depending from the carriage 15. The hanger 26 includes a floor 29 having an opening 30 over which the tundish 24 is pivotally mounted as indicated at 32. The tundish 24 has a refractory lining 41 which defines a closed pouring chamber 42 and an open basin 44 communicating with each other through a port 45. Basin 44 is positioned directly below the ladle nozzle 28. Pouring chamber 42 has a nozzle 46 for discharging a metered flow of molten metal into the mold 12 as controlled by a stopper 48. A lip 49 in the edge of basin 44 is aligned with a slag pot 50 for draining off accumulations of slag so the level of pure metal is always above the port 45.

In accordance with the invention, with the pouring sections 14, 14' in substantially abutting relationship as shown in FIGURE 1, the tundish nozzles 46, 46 have a given spacing along the line of movement 47 such that when one nozzle is over the mold in a discharge position, the other one is in an idle position adjacent the mold. Associated with each pouring section 14, 14 is a trough member 54, 54' pivoted adjacent opposite sides of mold 12 at 55, 55' and extending outwardly from the mold in opposite directions along the line of movement 47. The trough sections 54, 54' are operated on hydraulic cylinders 56, 56' in connection with the tundishes 24, 24 to conduct molten metal to the mould 12 in a manner to be described hereinafter. Since the trough members 5 5-, 54 are substantially similar, a description as to one will be understood as applying equally to the other and as before, like parts will be identified by like numerals with the addition of a prime mark.

Referring now to FIGURES 3 and 4, trough member 54' includes a generally rectangular frame 60' carrying a r bracket 62' for pivotal mounting of the trough member at 55 adjacent the mold as shown in FIGURE 1. The frame 60 supports bottom guide rollers 65' and side guide rollers 67 which cooperate to define a longitudinal trackway, generally indicated by numeral 68, within the frame 60'. A refractory chute 70 is constructed on a channel 71 supported by a box member 72' adapted to be reciprocally guided in the trackway 68. Supported within the frame 60' is a fluid cylinder 75' having an operating rod 76' pivotally connected to a bracket 80' carried by the box member 72 for extending or retracting the chute 70' on the trackway 68. A semicircular cutout portion 37 at the inner end of chute 70 mates in a complementary fashion with a semicircular cutout portion 87 of the companion chute 70 of trough member 54 to define a circular pouring opening 90 (FIGURE 2) aligned with the mold axis when the chutes 70, 7d) are in extended position as shown in FIGURES l, 2 and 6. A pair of gas burners 82 extend longitudinally along each side of chute 7t) and are connected to a suitable source of combustible gas, such as natural gas, to heat the metal stream and prevent excessive oxidation. The fluid cylinders 56, 56' raise or lower the trough members 54, 54' so that the outer ends of the chutes 70, 70 are above the top of the mold 12 in one position as shown best in FIGURES l and 6 or are lowered below the mold in a second position as shown in FIGURES 5 and 7.

A more complete understanding of the operation of the invention may be had by referring to the following description. Briefly, the method of operation involves pouring from one ladle until it is nearly empty and before its supply of metal is exhausted, bringing up a fresh ladle and beginning to pour from it so as to continue supplying the total requirements. The change from one ladle to the next is accomplished without interrupting the metered flow of metal to the mold.

Starting at some time while casting is in progress with the position of the apparatus as shown in FIGURE 1, let it be assumed that ladle 11 has nearly exhausted its supply of metal and ladle 11 which is substantially full of metal, has just been brought up and placed on carriage 15 but has not yet been tapped. The chutes 70, 70 are in the extended and elevated position as shown in FIG- URE 1. The circular pouring opening 90 formed by the mating inner ends of the chutes 70, 70' is slightly larger than the full flow cross section of the molten metal stream being emitted from the tundish nozzle 46' and when aligned with the nozzle, the metal enters the mold directly.

Before the metal supply from ladle 11 is completely exhausted, pouring sections 14, 14' are moved in tandem slowly to the right, as viewed in FIGURE 1, relative to the mold 12 such that the tundish nozzles 46, 46' are displaced along the line of movement 47 as depicted in FIGURE 6, 'Due to the fact that the outer ends of the chutes 70, 70' are elevated above the mold, the stream of metal from nozzle 46 will continue to flow to the mold 12 at the original pouring location as presently maintained by the opening 90.

When the flow diminishes from nozzle 46', ladle 11 is tapped and initial flow from nozzle 46 is begun to supplement the diminishing flow from nozzle 46, so as to maintain the total metered flow requirements of the mold. Gas burners 82, 82 are ignited as metal begins to flow in the chutes 70, 70 to keep the casting temperature of the metal streams at the proper level and to provide a reducing blanket of gas to prevent oxidation of the molten metal. As the metal supply diminishes from ladle 11' the slag level in basin 44 of tundish 24 reaches port 45'. At this point, stopper 48' is closed. To compensate, the stopper 48 of tundish 24 is opened sufficiently wide to continue supplying the total mold requirements. The pouring sections 14, 14 continue to move to the right until tundish nozzle 46 occupies the original pouring location vacated by nozzle i6. Now gas to the burners 82, 82 is shut oil and the cylinders 75, 75' and 56, 56' are retracted moving chutes 70, 70' to the retracted and lowered position shown in FIGURE 5. Tundish 24' may then be pivoted on hanger 26 at 32 so as to empty any remaining metal and slag into the slag pot 50'. The empty ladle 11 is picked up and carried to a melting furnace to receive a fresh batch of metal or is taken to a repair area where it is reconditioned. With the tundish 24 in the idle position a fresh tundish can be installed or relining and reconditioning carried on while casting proceeds from tundish 24.

If during any portion of the casting cycle an emergency arises while nozzle 46 or 46' is in the pouring location directly over the mold, either chute 76 or 70 can be extended completely under the tundish nozzle to divert the entire stream of metal from the mold and into a slag pot 50 or 50' as depicted in FIGURE 7.

As may be appreciated from the above description, the process continues by bringing a full ladle with new tundish to replace the empty one and moving the pouring sections 14, 14' in the opposite direction before the flow diminishes thus supplying an uninterrupted metered flow of metal to the mold 12.

Having thus described a preferred embodiment of the invention and its method of operation it will be appreciated that various modifications and changes may be made which would be obvious to those skilled in the art without departing from the invention as defined by the appended claims except insofar as they are limited by the prior art.

I claim:

1. A continuous casting installation comprising a mold adapted to receive a continuous supply of molten metal,

a pair of pouring vessels each containing a supply of molten metal to be cast movable on a common line of movement intercepting the mold, which line of movement extends from a pouring location above the mold in opposite directions to idle positions on either side thereof suchthat as one vessel is in the pouring location supplying a metered flow of metal to the mold, the other is in an idle position alongside and elongated means extending outwardly from adjacent the mold along the line of movement beneath the pouring vessel in the idle position, said means opening upwardly along said line of movement and inclined toward the mold for receiving and directing the flow of metal from said vessel into the mold during movement thereof relative to the elongated means whereby the mold is continuously supplied with a metered flow of molten metal during the transition of vessels between the idle and pouring locations. 2. A continuous casting installation according to claim 1 wherein the elongated means comprises a pair of trough members extending outwardly in opposite directions along the line of movement from adjacent the mold whereby pouring from either vessel may commence in the idle position.

3. A continuous casting installation according to claim 2 wherein one of said trough members is pivotally mounted adjacent the mold so that its outer end can be tilted below the top of the mold for discarding any portion of the flow from the vessel.

4. A continuous casting installation according to claim 2 wherein the adjacent inner ends of each trough member are in abutting relationship above the mold and have complementary semicircular openings to define a gravity flow pouring opening coinciding with the mold axis.

5. A continuous casting installation according to claim 2 wherein one of said trough members comprises guide means defining a longitudinal track-way intersecting with the mold which is pivoted adjacent thereto for movement in a vertical plane and a refractory channel is received on said guide means and is longitudinally movable thereon beyond the mold axis, the opposite end being tiltable below the top of the mold on said pivot whereby the metal flow may be diverted away from the mold.

References Cited UNITED STATES PATENTS 284,005 8/ 188 3 Hainsworth 164-266 1,336,768 4/ 1920 Warren 164--129 1,830,427 11/1931 Devillers 164296 2,252,945 8/ 1941 Palm 164--86 2,732,60 1 1/1956 Junghans 164-82 2,804,665 9/1957 Harter et al. 164--82 3,218,682 11/ 196-5 Namy 164-337 FOREIGN PATENTS 161,606 3/ 1955 Australia.

I. SPENCER OVER-HOLSER, Primary Examiner. R. S. ANNEAR, Assistant Examiner.

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