US3436023A - Apparatus for altering the position of a jet of molten metal,especially for continuous casting machines - Google Patents

Description

April 1, '1969 A, THALMANN 3,436,023

APPARATUS FOR ALTEEING THE POSITION oF A JET 0E MoLTEN METAL, ESPECIALLY FOR CONTINUOUS' CASTING MAcHINEs/ v of 4 Filed Marchv '7, 1966 --Sheet ,A

April l, 1969 APPARATUS FOR ALTERING THE POSITION O1 A JET OF MOLTEN METAL, ESPECIALLY FOR CONTINUOUS CASTING MACHINES Filed March v, 196e sheet 2 of 4 A. THALMANN 3,436,023

3,436,023 A JET oF Mo TING MACHINES LTEN AAPPARATUS FOR ALTER METAL, ESPECIALL Filed March '7 4 Sheet.

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United States Patent O U.S. Cl. 239-53 12 Claims ABSTRACT OF THE DISCLOSURE Apparatus for adjusting the orientation of a jet of molten metal issuing from an outlet opening of a container, such as a tun dish, includes a positioning element, having a discharge aperture therethrough, adjustably mounted downstream of the outlet opening with the aperture communicating with the latter for flow of molten metal serially through the outlet opening and the aperture. The cross sectional ilow area of the discharge aperture is less than that of the outlet opening, and means are operable to adjust the positioning element relative to the outlet opening to adjust the orientation of the molten metal jet. Means are also provided to cooperate with the discharge aperture to control the rate of ilow of molten metal therethrough.

Background of the invention This invention relates to .an apparatus for altering the position of a jet of molten metal, especially for continuous casting machines.

The ilow within the liquid core of a continuously cast strand, caused by the impact of the jet of molten metal, and its temperature, can inuence the formation of the solidified shell of the strand. For instance, erosion could take place on the inner side of the shell, weakening it to the extent that the ferrostatic pressure in the liquid core could cause one of these dangerous breakouts of the molten metal.

It' this erosion took place in the region of the mold, damage of the mold could take place, due to overheating the mold wall at the position where the shell is eroded. Furthermore, the erosion of the solidified shell promotes an uneven crystallization and could lead to stresses and bad structure. To avoid these disadvantages, the jet of molten metal is adjusted in relation to the mold section so that the flow in the liquid core, caused by the impact of the jet molten metal, does not decisively damage the solidi-tied shell.

When casting small cross-sections in multi-strand machines, it is especially important to position the jet of molten metal accurately. To enable such a positioning, special chutes, which distribute the metal to several molds, have been employed, but they have Well-known disadvantages. The most favourable solution was to employ a common tundish for several strands. In this case, an accurate positioning of the tundish nozzles was proved to ibe diticult. Besides, there is also the danger of distorting the tundish under the intiuence of heat during the cast, causing the distances of the nozzles to alter. This, in turn, causes the position of the jets ofmolten metal to alter relative t-o their molds, and in the worst case, the jet would be outside the section of the mold, which can lead to shutting off some of the strands. This of course would decrease the production rate ofthe plant.

When casting strands, which are guided in bent strand guiding means immediately below the mold, an accurate positioning of the jet of molten metal is especially important, because the effect of the jet on the solidifying shell, causing the flow within the liquid core to contact the shell more intensively at the outer radius of the strand, promotes erosion of the shell at this place.

A deviation of the jet of molten metal with magnetic means has also lbeen suggested. Such a deviation is relatively complicated and expensive. As a change of position is also caused when a change of direction of the jet is effected, the disadvantages would be that by the change of the angle of impact of the jet on the level of liquid metal the flow pattern within the liquid core could deteriorate.

In addition, it has been suggested to employ a sliding plug as a shut-off mechanism and as an element to control the flow from the tundish to the mold. By sliding parts of the plug relatively to each other, the discharge and and thus the quantity of the ow can be controlled. It can, however, not be prevented that by such an action the position of the jet of molten metal is altered.

The aim of the present invention is to obtain an apparatus for altering the position and direction of the jet of molten metal which ows out of a container without influencing the rate of ilow through the nozzle.

This is achieved by a positioning element with an opening for the ow at the outlet opening of the container. By laterally displacing this positioning element the Iposition of the jet of molten metal is altered without inlluencing the rate of flow before and after the change.

The use of a sliding plug is preferred for a container, whereby the opening in the container preceding the positioning element has a minimal size corresponding to approximately the sum of the maximum sliding distance of the element plus the diameter of its opening.

Further embodiments of the invention chosen by way of example are illustrated in the accompanying drawings, in which:

FIG. l is a tundish with a sliding plug and its device to alter the position of the jet of molten metal rby displacing it in one direction;

FIG. 2 is a section on line II-II of FIG. l;

FIG. 3 is an embodiment according to FIG. 1 with an inclined hole for the jet of molten metal;

FIG. 4 is a tundish with a sliding plug and its device to alter the position of the jet of molten metal in two directions;

FIG. 5 is a section on line V-V of FIG. 4;

FIG. 6 is a positioning element with branched ofi discharge openings;

FIG. 7 is an embodiment with an extension tube;

FIG. 8 is an embodiment similar to the one of FIG. 7;

FIG. 9 is a tundish with stoppered nozzle and a device to change the position of the jet of molten metal along a circular path;

FIG. l0 is a tundish with a of the and FIG. ll is a section on line XI-XI of FIG. l0.

FIGS. l and 2 show part of a tundish 1 lined with refractory material 2 with an opening 2 accommodating a spout 4 which has a longitudinal opening 11. The face 5 ot the spout is accurately machined, for instance ground. A sliding plug 6 is situated just underneath the spout 4. This sliding plug consists of a positioning element 7 with an opening 8 for the flow and is followed by a closing element 9 with a discharge opening 10. These elements consist of refractory material embedded in a steel frame. The opening 10 can also consist of a separate nozzle of refractory material. The positioning element 7 and the closing element 9 are guided in a guidance 12 which conof a sliding plug combined device for universal change position and direction of the jet of molten metal;

sists of Z-proiles. This guidance 12 can be displaced in a further guidance 13 which is rigidly connected to the tundish. There is also a bearing 15 connected to the tundish together with a spindle 16. A hand wheel 17 is ixed on the spindle 16 having an external thread 18 at one end. A nut 19, having an internal thread which corresponds to thread 18, consists of two halves 20 and 21. The half 20 is connected with a lever 22 and the other half 21 is connected with a lever 23. The lever 22 is connected with a bearing piece 24 and the lever 23 with a bearing piece 25. Both of these levers can pivot around an axis on these bearing pieces. The bearing piece 24 is rigidly connected with the guidance 12, whereas the bearing piece 25 is mounted on the closing element 9.

FIG. 4 shows means to engage either half 20 or 21 or both together with the thread 18. By turning the hand wheel 17, the guidance 12 with the elements 7 and 9 can be displaced into any position; also the closing element 9 can be displaced in relation to the positioning element 7. The guidance 12 can be fastened onto the guidance 13 by a screw 26 when half 20 is disengaged. This is necessary to prevent that frictional forces can dislocate the positioning element 9.

By displacing the guidance 12 together with the elements 7 and 9, for instance by engaging halves 20 and 21, a change of the position of the jet of molten metal can be achieved without altering the rate of ow from the tundish to the mold. The rate of flow of course is still dependent on the ferrostatic pressure in the tundish or the size of the discharge nozzle opening, etc. To enable the position of the jet of molten metal to be altered, the spout 4 must have an opening 11, the minimum length of which corresponds to approximately the sum of the maximuni sliding distance of the positioning element 7 plus the diameter of the opening 8.

To avoid freezing of the molten metal on the top face of the positioning element 7, an induction heating system could be built into this element.

The disadvantage of arranging the closing element 9 below the positioning element 7 is that when the iiow is changed or the tundish is opened or closed by the closing element, a change of position of the iet of molten metal occurs. To avoid such a change, the closing element 9 can be arranged above the positioning element 7.

FIG. 3 shows a similar embodiment to FIG. 1. The difference consists in that the closing element 7 is follower by the positioning element 9. The positioning element 9 has a declined discharge opening 35, which directs the jet of molten metal at any desired angle, resulting in a different ow pattern Within the liquid core of the strand which is advantageously adapted to the strands guided in curved strand guiding means. The erosion of the solidiiied shell can thus be kept to a minimum. The discharge opening could also at the beginning be perpendicular to the upper face of the positioning element 9' and afterwards change to an inclined direction. If, as shown in FIG. l, the closing element 9 is below the positioning element 7, any inclined discharge opening 35 should be located in the element 9.

FIGS. 4 and 5 show a device employing a sliding plug, where the jet of molten metal can be displaced laterally into any desired position. The tundish can be opened and closed without any change in position of the jet of molten metal.

A spout of refractory material with a relatively large opening 41 is built into the opening 3 of the tundish. A positioning element 42 is arranged underneath the spout 40. An upper positioning plate 43 with a discharge opening 47 and a lower plate 44 with a discharge opening 48 are built into a steel housing. Both elements are made of refractory material. The opening 48 can also be inclined to achieve the desired and above explained effect. A closing element built inside a steel frame in which there is a closing plate 46 of refractory material with a discharge opening 49 is situated between the plates 43 and 44. The closing element 45 can be adjusted relative to the positioning element 42. A guidance 50 is attached to a tundish 1. A guiding element 51 is guided in the guidance 50. This arrangement allows the positioning element 42 to be moved perpendicular to the direction of movement of the closing element 45.

Another guidance 55 is attached to the tundish 1. It takes a bearing piece 56 which accommodates a sleeve 57 which can be turned by the hand wheel 17. Inside this sleeve there is a spindle 58 having at one end a thread 59 and a square head 60. The end of sleeve 57 forms a shoulder 61 with a square socket which lits onto head 60.

There is also a rack 65 fastened on the tundish 1. This rack 65 can be put into mesh with a gear 66 fastened onto the sleeve 57.

The nut 19 which consists of two halves 20 and 21 corresponds to thread 59. Again, these halves 20 and 21 are connected with their corresponding lever 22 and 23. The lever 22 is influenced by a magnet 70 and the -lever 23 by a magnet 71. The magnet 70 is fastened onto the bearing piece 72 and the magnet 71 onto the bearing piece 73. There is a spring 74 fastened on the bearing piece 72 which presses lever 22 onto the thread 59, and a spring 75 fastened on bearing piece 73 presses lever 23 onto the thread 59. These levers pivot around bearings 76 and 77, respectively, mounted on the bearing pieces 72 and 73, respectively. The bearing piece 72 is rigidly iixed with the closing element 4'5 and the bearing piece 73 with the positioning element 42.

To position the jet of molten metal, the following procedure can be adopted:

(a) displacement in a direction parallel to the axis of the spindle 58:

The .square head 60 is engaged with the end of sleeve 57. The springs 74 and 75 engage halves 20 and 21 with the spindle 58. By turning the hand wheel 17, the positioning element 42 and the closing element 45 are displaced.

(lb) displacement in a direction perpendicular to the axes of the spindle 58:

By pulling the hand wheel 17 away from the tundish opening, the square head 60 and the sleeve '57 are disconnected. At the same time, the gear 66 meshes with the rack 65. Therefore, the bearing piece 56y can be moved in the guidance 55 by turning the hand wheel 17 together with the positioning device 42 which is fastened onto the spindle 58, nut 19 and bearing pieces 72 and 73.

It is therefore possible to position the jet of molten metal to any given point by employing the abovementioned procedures.

For opening and closing the tundish as well as for controlling the rate of iiow of molten metal from the tundish to the mold, it is only necessary to displace the closing element 45. For this purpose, the magnet 71 pulls the half 21 from the thread on the spindle 58, leaving the other half 20 engaged with this spindle. By turning the hand wheel 17, the spindle 58 and the square head 60, the bearing piece 72 and the closing element 45 are displaced. A device not shown on the drawings holds the positioning element 42 which otherwise could be dislocated by frictional forces between the plates 43 and 46 or 44 and 46.

To reduce the depth at which the eiect of the ow on 4the solidiiied shell could cause any damage, the lower positioning plate 44 can be so high that the discharge opening 48 shortly below the contact area with the closing element 45 branches olf in at least two further discharge openings 48', whereby lthe section of these openings can be sized to accommodate any desired ilow. This arrangement can be seen in FIG. 6i. It is especially important when casting heavy slabs. There is also the possibility to arrange the above ilow division inside the closing element which should then be situated below the positioning element.

FIG. 7 shows an embodiment of a sliding plug combined with an extension tube. This extension tube 27 having an opening is built onto the closing element 9. The exit opening 28 is located slightly above the level 52 of the molten metal 54 in a mold 53 and can also extend to below this level. If, as shown in FIG. 3, the closing element 7 is above the positioning element 9', the extension can be effected by a tube-like design of the positioning element 9 or by fastening an extension tube onto the positioning element 9. The discharge opening 10 can also be inclined.

FIG. 8 shows another embodiment of an extension tube design consisting of at least two sections 29 and 30 with an opening 10. The first section is built onto the closing element 9. Both sections, which are of refractory material, are surrounded with a tube-like shell and connected together by a thread. The flow of the molten metal is deiiected in the lower section 30 and is discharged in the embodiment according to FIG. 8 through holes 31 below the level S2 of the molten metal 54 in the mold 53. Thus, the depth at which the effect of the iiow on the solidified shell could cause any damage can be reduced. Another advantage of the embodiment shown on FIG. 8 is that the lower section 30 which wears more rapidly than the others, due to erosional effects of the surrounding molten metal 54, can be replaced by a new section without changing the other sections.

FIG. 9 shows an embodiment of a device which allows the position of the jet 0f molten metal to be altered when stoppered nozzles are used. A spout 80* is built into the bottom of the tundish 1 which can be closed by a stopper 81. This stopper is controlled by known means. A circular guidance 82 is fastened onto the tundish 1. A flange 84 is mounted on its upper part in the circular guidance `82, and can be rotated by a Worm 86 engaging in a worm gear 85 which is fastened onto the flange 84. Inside this tiange 84 there is a positioning element 83 of refractory material. This element 83 accommodates an inclined bore 87, the exit of which is positioned a distance R away from the center of the spout `80. By turning the positioning element 83, it is possible to displace the jet of molten metal along a circular path, which allows an accurate positioning of the jet in any direction. For many purposes, for instance when casting slabs, an accurate positioning perpendicular to the longer side of the slab is sufficient. The deviation from a straight line, due to the circular movement, in a direction parallel to the longer side of the slab is so small that it has no influence on a possible erosion of the solidified shell of the strand.

Instead of using a stoppered nozzle a disk of refractory material with one or more discharge openings could be arranged below the positioning element 83 and can take over the closing and controlling functions. Several discharge openings would have the advantage that .in case of clogging of an opening another one would take over the discharge function, and so, the casting operation would not have to be interrupted.

FIG. l0 and 11 shown a device for universally adjusting the position and direction of the jet of molten metal. A spout 90 is built into the bottom of the tundish 1. Again a circular guidance 91 is fastened onto the tundish 1. A positioning element 92 of refractory material can be turned within this circular guidance 91. The positioning element 92 has .a bore 93 which is a distance M away from the axis of the spout or from .the axis of positioning element 92. The bore 93 is connected with the discharge opening of the spout 90 by an inclined discharge opening 94. Within the bore 93 a plug of a cock 95 with an opening 96 can be turned by a bar 97 which is rigidly connected to the plug of a cock. The positioning element 92 has at the bottom a relatively large opening 98.

By turning the plug of cock 95 in the bore 93 its opening 96 can be connected or respectively disconnected withthe discharge opening 94, thus opening or respectively closing the tundish. By employing a force perpendicular to the axis of the bar 97 onto the bar, the positioning element 92 can be turned, whereby the jet of molten metal is displaced as a result of the eccentricity M. By moving the plug of a cock in .a direction parallel to its axis any deviation from a straight line caused by the circular movement of the jet can be taken up so that there is only a displacement in one direction. By -a limited circular movement of the plug of the cock 95 a change of direction of the jet can be effected. The opening 96 is bigger on the side -of the opening 94 to keep the flow during the above-mentioned turning movement as constant as possible. Any desired change in direction and position of Ithe jet of molten metal is thus possible without changing the rate of `flow of molten metal from the tundish to the mold. A change of flow could be achieved by turning the plug of a cock or, when the associated change of angle is lundesired, by displacing the plug of a cock along its axis.

In the examples cited all movements are applied by mechanical means. They could also be done by other means, for example by hydyraulic devices. To decrease the influence of erosion, the discharge openings can be selectively cooled.

It has been known in the art of continuously casting slabs to apply more than one jet delivering molten metal from the tundish to the mold. Normally, there is only one discharge arrangement with a device for regulating the rate of iiow, so that only one discharge arrangement with a device for changing the position of the jet of molten metal and the rate of ow is necessary, whereas the other discharge arrangements would only have to be equipped by the apparatus for changing the position of the jet.

The apparatus according to the present invention can also advantageously be used for casting molds because the relatively small openings of the molds could necessitate an accurate positioning ofthe jet of molten metal.

What is claimed is:

1. Apparatus for adjusting the orientation of a jet of molten metal issuing from an outlet opening of a container, said apparatus comprising, in combination, a positioning element, having a discharge aperture therethrough, adjustably mounted downs-tream of said outlet opening with said aperture communicating with said outylet opening for liow of molten metal serially through said outlet opening and said aperture; the cross sectional iiow area of said discharge aperture being less than that of said outlet opening; means operable to adjust said element relative to said outlet opening to adjust the orienta-tion of the molten metal jet; and flow rate control means, separate from said positioning element and mounted for `adjustment relative to said positioning element, cooperating with said discharge aperture for controlling the rate of -flow of said molten metal through said discharge aperture; whereby the rate of flow of said molten metal through said discharge aperture may be adjusted independently of adjustment of said positioning element.

2. Apparatus according to claim v1 including an extension tube built onto said positioning element.

I3. Apparatus as claimed in claim 1, in which said positioning element is a slidably mounted plug; said outlet opening having a minimal size equal to substantially lthe sum of the maximum sliding displacement of said plug plus the dimension of said discharge aperture in the direction of such sliding displacement.

4. Apparatus as claimed in claim 3, in which said flow rate control means controlling the rate of iiow of said molten metal through said aperture comprises a con- -tainer closing element, formed with a discharge opening, positioned downstream of said positioning element.

5. Apparatus as claimed in claim 3, in which said flow rate control means controlling the rate of flow of said molten metal through said aperture comprises a container closing element, formed with a discharge opening,

interposed be-tween said positioning element and said outlet opening.

`6. Apparatus as claimed in claim 3, in which said positioning element comprises two components each having a discharge opening therethrough, said components being spaced apart in the direction of metal flow therethrough; said flow rate control means controlling the rate of ow of saidmolten metal through said .aperture comprising a closing element for the container outlet opening positioned between the two components of the positioning element.

`7. Apparatus according to claim 4, including an extension tube built onto said closing element.

l8. Apparat-us according to claim 7, in which said extension tube has an exit opening located below a level of molten metal.

9. 4'Apparatus as claimed in claim 1, in which the axis of said discharge aperture extends atan Aangle to the axis of said outlet opening.

10. Apparatus as claimed in claim 4, in which the axis of the discharge opening in said closing element is inclincd relative to the axis of said outlet opening.

11. Apparatus as claimed in claim 3, in which said positioning element :is mounted for adjustment in one direction.

`12. Apparatus as claimed -in claim 3, in which said positioning element is 4mounted for adjustment in two respective directions, the minimu-m cross sectional area of said outlet opening being related to .the cross sectional dlow area of said discharge apenture in such a manner that the full cross sectional flow area of said discharge aperture is always in communication with said outlet opening.

References Cited FOREIGN PATENTS l838,520 6/1960 Great Britain.

EVERE'IT W. KIRBY, Primary Examiner.

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