US3773103A

US3773103A - Continuous casting machine

Info

Publication number: US3773103A
Application number: US00164404A
Authority: US
Inventors: M Burkhardt; H Huber; J Zeller; C Chateau; M Schmid
Original assignee: Concast AG; Concast Inc
Current assignee: SMS Concast AG; SMS Concast Inc
Priority date: 1970-07-21
Filing date: 1971-07-20
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20
Also published as: AU3146771A; BE770233A; FR2099501B1; JPS5119809B1; DE2136146A1; DE2136146B2; AU461822B2; CA944123A; DE2136146C3; FR2099501A1

Abstract

A continuous casting machine is provided with a casting position and at least one preparation position. At least two molds are provided, with each mold connected to a section of a roller apron to form a mold unit which is so mounted that it is movable as a unit between the casting position and a preparation position and vice versa. While metal is being cast through one mold unit at the casting position, the other mold unit at a preparation position may be prepared for use in the next casting operation, including insertion of a dummy bar. When the mold unit is at the casting position, the movable section of the roller apron is aligned with a fixed section of the roller apron, so that the two sections form a continuous guideway for the casting leading to withdrawal rollers.

Description

United States Patent 1 Burkhardt et al.

[ Nov. 20, 1973 CONTINUOUS CASTING MACHINE [73] Assignees: Concast AG, Zurich, Switzerland; Concast Incorporated, New York, NY.

[ Filed: July 20, 1971 1211 Appl. N0.: 164,404

[30] Foreign Application Priority Data 164/282, 283, 283 R, 283 S, 283 M, 283 MS, 283 MT; 193/35 R, 35 A, 35 SS, 35 C, 35 TE, 35 MD, 35 .l, 35 G, 35 B, 35 S; 266/13 [56] References Cited UNITED STATES PATENTS 3,495,651 2/1970 Rokop 164/282 X 3,167,829 2/1965 Hess 164/282 3,446,270 5/1969 Michelson. 164/282 3,346,036 10/1967 Tarmann.... 164/282 X 3,590,908 7/1971 Reinfeld 164/282 2,920,359 1/1960 Easton 164/274 X 3,273,208 9/1966 Greenberger.. 164/274 X 3,620,285 11/1971 Olsson 164/282 3,672,438 9/1970 Hofmann 164/282 Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown Att0meyNichol M. Sandoe et al.

[57 ABSTRACT A continuous casting machine is provided with a casting position and at least one preparation position. At least two molds are provided, with each mold connected to a section of a roller apron to form a mold unit which is so mounted that it is movable as a unit between the casting position and a preparation position and vice versa. While metal is being cast through one mold unit at the casting position, the other mold unit at a preparation position may be prepared for use in the next casting operation, including insertion of a dummy bar. When the mold unit is at the casting position, the movable section of the roller apron is aligned with a fixed section of the roller apron, so that the two sections form a continuous guideway for the casting leading to withdrawal rollers.

19 Claims, 9 Drawing figures PAIENIEUunvzo um 3.773.103 sum 10F 4 30 FIG.2

PATENTEDNDV 20 ms 3773.103 SHEET REF 4 FIG? FIGS

CONTINUOUS CASTING MACHINE The invention relates to a continuous casting machine for steel comprising at least two oscillable molds, a tundish associated with each mold for pouring steel into the mold when the mold is in casting position, a segmented roller apron comprising a movable section and a fixed section, each of said sections being equipped with secondary cooling means, strand with drawing means, a dummy bar and a dummy bar handling mechanism. Each mold, together with a movable section of the roller apron which directly adjoins the mold forms a mold unit which is movable into and removable from the casting position. When the mold unit is in casting position the movable section of the roller apron is aligned with the fixed section of the roller apron and forms a continuous guideway for the casting leading to the strand withdrawing means.

The efficient operation of a continuous casting machine when casting steel requires complete coordination between the tapping cycles of the hot-metal production units and the casting cycles of the continuous casting machine. A complete casting cycle comprises the actual pouring time of one continuous strand and the preparation time required to prepare the machine for casting the next strand. During the preparation time the end of the first strand must be fully withdrawn from the machine, a dummy bar must be introduced into the roller apron, and the dummy bar head must be moved into and sealed in the mold. This preparation time, which requires at least 30 minutes in most steel casting machines, adversely affects the productive capacity of the machine. This capacity may be further reduced by planned interruptions, such as to make changes in the mold and roller apron to change the cross section of the strand, or by changes in the type of the steel to be cast, as well as by unforeseen interruptions, such as metal breakouts.

It is known to increase the capacity of a continuous casting machine by using what is known as continuous continuous casting in which a series of successive ladle charges are poured without interruption, because preparation time will only be required before the casting of the first ladle. However, continuous continuous casting is only possible when the tapping times ofthe hot-metal producing furnaces are exactly synchronized with the casting rate of the continuous casting machine. Events which disturb this synchronism can never be completely eliminated. Moreoever, continuous continuous casting is usually practiced only when the type of steel and the cross section of the strand remain unchanged. Metal breakouts, damaged refractory parts or other difficulties may necessitate the stopping of the continuous continuous casting process. Such problems limit the usefulness of continuous continuous casting, particularly in steel works which produce a wide variety of products.

It has been proposed to reduce the preparation time elapsing between the completion of one strand and the beginning of the next, by introducing a dummy bar head into the mold or into a spare mold, locking it in place, and then preparing the head for beginning the next cast while the previous strand is still in the roller apron and is in the course of being withdrawn. As soon as the point of entry of the dummy bar into the roller apron has been cleared by the withdrawing strand, the dummy bar may be introduced into the roller apron and advanced and connected to the head which is already in the mold prepared for casting, so that a new casting can begin immediately. Some reduction in preparation time can thus be acieved, but the withdrawal of the previous strand, the introduction of the dummy bar, the change-over to a different casting section and other operating difficulties nevertheless still cause considerable losses of time.

It has also been proposed to combine the mold, the mold table and a part of the roller apron which is adjacent the mold into one unit which can be removed as a unit from the casting position and a replacement unit can be substituted by a crane. This procedure reduces the preparation time somewhat, particularly when the casting cross-section has to be changed or when operating trouble such as a breakout occurs. However, considerable time is still required for introducing the dummy bar into the unit and for sealing the dummy bar head in the mold.

In yet another known continuous casting machine the mold is sealed with a mold plug that is substantially shorter than the distance between the mold and the first driven roller of the roller apron. This mold plug can be moved downward in the roller apron by conveyor chains which are located on opposite sides of the roller apron until it reaches the first driven roller. In a position located to one side of the normal casting position the mold plug is introduced into a mold and secured to it by locating means. The mold is then transferred into normal casting position and the mold plug is inserted into the roller apron and coupled to the chain conveyor. Although in this machine the mold plug is introduced into the mold away from the normal casting position, the following operations which increase the preparation time of the machine must still be performed after the mold has been transferred into casting position: (a) The mold plug must be introduced into the roller apron and coupled to the conveyor. (b) The locating means of the plug must be removed and it must be manipulated by the conveyor into the desired position in the mold and then sealed. (c) In continuous casting machines having guide means on all four sides of the casting, the guide means on two opposite sides must be adjusted to the new width and must be aligned to the position of the mold. (d) The pouring of metal can start only when the mold is in casting position. (e) In the case of operating difficulties, particularly in the event of a metal breakout, the same repair time is required as with a conventional plant.

It is an object of the present invention to provide a continuous casting machine in which the preparation time required between the end of one cast and the beginning of the next is substantially less than that required by prior methods or procedures, so that a high productive capacity of the machine is obtained.

This object is accomplished by providing two separate mold units, each unit comprising a mold and a movable section of the roller apron which directly adjoins the mold, with each of said roller apron segments having at least one driven roller therein. One mold unit is in casting position, while the other mold unit is in preparation position. The unit which is in preparation position cooperates with a dummy bar handling means for the insertion of a short dummy bar into the unit.

The invention permits the reduction of the preparation time to 5 to 10 minutes, depending on the size of the machine. The mold cross-section and/or the type of steel of consecutive castings can be changed without increasing the preparation time. In the event of a breakout of metal which usually occurs in the zone of the roller apron immediately adjacent the mold it is often possible to resume casting after a very short time by replacing the damaged mold unit by the other unit which is in the preparation position. The duration of a shut-down due to such causes can thus be minimized.

Drive means are provided for inserting a dummy bar into the mold unit while it is in the preparation position. However, separate drive means for completely inserting the dummy bar into the mold unit are unnecessary if, according to another feature of the invention, means are provided for driving the driven roller of the mold unit whilst the unit is in the preparation position.

To avoid having to fill the mold with coolant and to vent it after it has been transferred from the preparation position into the casting position, a further feature of the present invention provides the supply and return pipes for the coolant of the mold with valves to prevent the coolant from draining.

It is also possible to introduce the dummy bar into the mold unit through the mold from above when the mold unit is in the preparation position.

However, in order to clear the casting platform of apparatus for the handling of a dummy bar and also in order to reduce the length of the feed path of the dummy bar to a minimum, it is proposed according to another preferred feature of the invention to introduce the dummy bar into the mold unit from below through the section of the roller apron attached thereto. Preferably the dummy bar handling device is equipped with a roller table which may be tilted to cooperate with the section of the roller apron which is a part of the mold unit.

Moreover, for the purpose of axially aligning the movable and fixed sections of the roller apron with allowance for thermal expansion, the movable section of the roller apron may be tiltably mounted at its end adjacent the mold, while the other end bears against the structure of the machine when it is in casting position.

According to one form of the invention, the length of the casting platform may be shortened by mounting the tundishes to be swivelled about a kingpost located on the operating side of the mold.

It may often be useful to provide an emergency cutting station between the movable section and the fixed section of the roller apron so that in the event of a breakout, the damaged casting may be cut up and removed piece by piece, so that the casting operation can be resumed within a few minutes.

The mold unit can be lifted into the preparation position and then back again into the casting position by a crane. However, particularly in the case of multiple strand machines in which the casting ladies are brought up by a crane, an interruption of the casting process and an increase in the loss or productive time cannot be avoided. According to the present invention it is therefore proposed to mount at least one mold unit on horizontal transporting means. Conveniently, one or more preparation positions may then be located laterally of the casting position and the transporting means may be cars that can be moved laterally.

In order to avoid the need of mechanical and/or hydraulic couplings for the several systems of the unit, for instance for mold oscillation, for driving the oilhydraulic motors of the driven rollers and for pressing the driven rollers against the strand, for lubricating the mold and so forth, another feature of the invention proposes to provide the unit with at least one emergency generator.

After use in starting a casting operation, the dummy bar can be quickly and conveniently returned to the one or the other of the two preparation positions which are located laterally of the casting position. For this purpose means are provided for handling the dummy bar including means for the transverse and longitudinal transportation of the dummy bar, the transverse transporting means interconnecting with the longitudinal transporting means located on each side of and above the strand guide means.

When the cross section of the casting is to be changed, it may also be necessary to change the dummy bar head and/or the dummy bar. According to yet another feature of the present invention this can be easily and conveniently done if the transverse transporting means comprise a roller table mounted on a car, traveling on tracks which extend to an area where dummy bars and dummy bar heads are stored.

For improving the freedom of movement of the casting platform, a cover may be attached to the mold unit transport car to move over the preparation position when the car moves the mold unit to its casting position.

The cost of the dummy bar handling means can be reduced substantially if, according to a further feature of the invention, the two mold units share a common preparation position. Such an arrangement may be particularly space-saving if the mold unit transport car is a turntable.

In order to save even more space it is advantageous that the turntable and the swivelling tundishes have a common pivot post.

It may be desirable for spcial reasons, such as a further reduction of the preparation time, and/or for fixing the dummy bar in the mold, to start pouring the metal into the mold when the mold unit is still in the preparation position, or when it is moving into casting position. For this, the tundish and the mold unit must be aligned and must move with the same speed.

For a twin-strand casting machine a particularly com pact and technically superior arrangement results when both units which are necessary for each strand are mounted on a common turntable, and by locating the two turntables adjacent to each other.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying schematic drawings in which:

FIG. 1 is a section of a continuous casting machine taken on the line I I of FIG. 3.

FIG. 2 is a secton taken on the line II II of FIG. 3.

FIG. 3 is a plan view of the continuous casting machine.

FIG. 4 is a plan view of another embodiment of a continuous casting machine according to the present invention.

FIG. 5 is a section taken on the line V V of FIG. 4.

FIG. 6 is a plan view of yet another embodiment of a continuous casting machine according to the present invention.

FIG. 7 is a section taken on the line VII VII of FIG.

FIG. 8 is a section taken on the line VIII VIII of FIG. 6, and

FIG. 9 is a section of the inlet and outlet pipes for mold coolant for mold units which are arranged on a turntable. 7

Referring to H6. 1, a ladle l carrying molten steel is located above and in position to pour steel into tundish 2. The tundish is positioned to pour into an oscillable mold 3 in which the cast strand begins to form and from which it moves into a secondary cooling zone wherein it is supported and guided by a roller apron comprising a movable section 8 and a fixed section 9. The section 8 of the roller apron and the mold 3 form a mold unit that is removable as a unit from the casting position shown. The fixed section 9 of the roller apron and strand withdrawing means 7 are aligned with the mold unit 10 when it is in casting position 4. The withdrawing means 7 also preferably functions to straighten the strand. The withdrawing means 7 may be followed by a cutting station 6. Both movable section 8 and fixed section 9 of the roller apron are fitted with customary secondary cooling equipment (not shown) for direct application of coolant to the strand. The mold units 10 are provided with means for holding and feeding the dummy bar. For this purpose section 8 of the roller apron is equipped with at least one driven roller 11 so that the dummy bar can be moved or locked in the unit 10. If desired several such rollers 11 and 12 in the unit 10 are driven rollers and hydraulic means may be provided for pressing them against the strand or dummy bar.

In the case of dummy bars which are themselves provided with means for holding them inside the unit 10, or for horizontal machines, no special holding means are needed in the unit 10.

Beyond the roller apron is located a dummy bar tilting table 15 which is positioned to intercept and detach a short dummy bar 18 from the strand. After detaching the dummy bar from the strand, the table is swung to a horizontal position from which the dummy bar may be moved onto a transverse transporting car 17. The dummy bar 18 may be as long or shorter than the segment 8.

As shown in FIGS. 1, 2 and 3, the mold unit 10 is mounted on horizontal traversing equipment comprising a car 30 which is movable on wheels 35 laterally across the longitudinal axis of the strand.

FIG. 1 shows the casting position 4 of the machine with the ladle l and the tundish 2 in position to pour metal into the mold 3 from which the partially solidified strand is delivered to the movable section 8 of the roller apron through which it proceeds to the fixed section 9 and thence to the withdrawing means 7. The dummy bar 18 has been deposited on the car 17. While casting is proceeding at the casting position, another mold unit and tundish may be prepared for casting as shown in FIG. 2.

in F105. 2 and 3 a second mold 3' and second movable section 8' of the roller apron forming a second mold unit 10' which together with a second tundish 2' is carried on car 30 located in a preparation position 5. While in this position, the dummy bar 18 may be moved from the car 17 further along the conveyor 16 to a position adjacent the section 8' of the roller apron of unit 10'. This conveyor 16 comprises a transverse transporting car 17, a fixed roller table 20 and a tiltable roller table 22 located below section 8 of the roller apron. A power cylinder unit 24 is provided to tilt the roller table 22 about a pivot 25 to bring it into alignment with section 8' of the roller apron. The tiltable roller table 22 is provided with means, such as a driven roll 26, for feeding the dummy bar into the section 8. The movement of the dummy bar into the section 8' may be assisted by the rollers 11 and 12 which can be driven even when the mold unit 10 is in the preparation position.

While in the preparation position of HG. 2, the tundish 2 may be prepared to receive metal by heating it by a gas burner.

FM}. 3 shows the lateral disposition of the two preparation positions 5, 5' in relation to the casting position 4. For greater clarity the ladle l is not shown in FIG. 3. Rails 31 are mounted on the platforms 33 of the cars 30 and 30' in order to facilitate moving the tundishes 2, 2 from the preheating stations 32 respectively 32' to the casting position.

The car 17 for the transverse transport of the dummy bar runs on rails 27 and can transfer the dummy bar from the tilting table 15 to either of the roller tables 20, 20'. The car 17 also services a stockpile 28 of dummy bars and dummy bar heads of different cross sections.

Platforms 33 of the cars 30, 30 are preferably long enough to project beyond the end of the casting platform when in the preparation position and to cover the preparation positions 5, 5' when the cars are moved to casting position so that no opening will be formed in the floor.

The operation of the machine may be described with reference to a situation in which, while casting a particular cross section at casting position 4, it is desired to prepare for changing the cross section of the next casting. The mold unit 10' in the preparation position 5 is already being adjusted to the new cross section whilst casting continues in position 4. The transverse car 17 then picks up a dummy bar 18 of the proper configuration from the stockpiling area 28 and conveys it to the roller table 20 along which it travels to the tiltable roller table 22. As soon as the mold 3' and the segment 8' of the roller apron have been adjusted to the new cross section, the roller table 22 is then tilted until the head of the dummy bar 18 is correctly aligned with the section 8 of the roller apron. The driven roller 26 then drives the dummy bar 18 into engagement with the driven rollers 11 and 12 which may be provided with oil-hydraulic motors and hydraulic devices which press them against the strand and cause them to feed the strand. Such devices may be automatically coupled to pressure-generating elements when they reach the casting position 4 or the preparation position 5. The rollers 11 and 12 advance the dummy bar 18 until its head enters the mold. Then the hydraulic pressure device is activated to tighten the roller pairs to hold the dummy bar in this position. The tiltable roller table 22 is then restored to horizontal position. Meanwhile the dummy bar head may be sealed inside the mold. When this has been completed, the mold unit 10' is ready for casting and can be moved into casting position when needed.

Shortly before the pouring of metal into mold 3 ceases, the preheated tundish 2' is moved to a location above the mold 3' and is aligned with the mold. As soon as the end of the strand has left section 8 of the roller apron, the mold unit 10, including the tundish 2, is moved by the car 30 into the preparation position 5. Then the car 30 moves the tundish 2' and the mold unit 10' into casting position 4 so that the section 8' of the roller apron is aligned with the fixed section 9 of the roller apron. Thereupon pouring of metal may begin. Shortly thereafter the hydraulic locking of the dummy bar in the segment 8' is released and the roller pairs ll and R2 are driven to start withdrawing the dummy bar and the partially solidified strand. After the leading end of the dummy bar has passed the withdrawing unit 7, the dummy bar is withdrawn by a chain or cable connected to a winch on the tilting table 15. As the dummy bar head reaches the table 15, it is tilted into a horizontal position which automatically detaches the dummy bar head from the strand. The dummy bar 18 is then pushed onto the car 17 and conveyed laterally to the roller table 20 along which it is conveyed to the tilting table 22'. Thereafter the dummy bar is moved into the mold unit ill which is in the preparation position and is prepared for the next casting. Alternatively, the unit may be fitted with a different dummy bar before the dummy bar from the preceeding casting has become available.

FIG. 3 illustrates another embodiment of a continuous casting machine in which the mold unit it) is in casting position 4 and a mold unit 10' is in the preparation position 5. Mold units Ml and ill are both mounted on a common car dl. Tundishes ill and d3 are mounted for swiveiling on a kingpin 42 located adjacent the operating side of the mold. The tundish 43 is located above the mold 3 in pouring position, and the tundish 43' is located at a preheating station which is equipped with a gas burner 45. The second preparation position 5 may be covered by a folding shutter 46. This shutter 46 is attached to the car 41 and is folded or unfolded by the movement of the car.

In FIG. 5 movable section 8 of the roller apron can be tilted about a pivot Sl which is located adjacent the end which faces the mold 3, while the opposite end of the section 8 is supported by an abutment 52 which bears against the structure 53 when the section is in casting position. This tiltable mounting permits adjustment to compensate for inaccuracies in the roller apron alignment which may be due to tolerances in the transverse moving system and to unequal thermal expansion of the two roller apron sections S and 1G.

in order to enable the mold unit 10 to be moved out of the casting position 4 when a breakout of metal has occurred, and also in order to enable the casting to be withdrawn from the other section 9 of the roller apron, an emergency torch cutter 55 is provided between the two sections 8 and 9. if the roller spacing between the segments 3 and Q is narrow, additional space for a cutter can be created by lifting or lowering the mold unit it) or the car at.

The dummy bar handling means comprises hoisting means 56 carrying a magnet 57 which lifts the dummy bar off the tilting table and lowers it onto a roller table 5%.

FIG. 6 shows a twin-strand machine in which each of the two turntables fill and 60 carries a mold unit it) in casting position and a mold unit lltl in preparation position. In such an arrangement casting may proceed in one or both of the units 10 depending on the requiremerits and circumstances. The positions 611 and 63' are provided as preparation positions for the two mold units 10. Such a machine may be equipped with a common tundish (not shown) for both mold units Ml, or may have, as indicated in the drawing, two separate tundishes 65 and 65' for each strand. In a particularly useful arrangement, the kingpin 62 for swivelling the tundishes 65 and 65 serves also as the axis of rotation for the turntable 60. With such an arrangement it is possible to center the tundish 55 with respect to the mold unit 10 while it is still in the preparation position 611, and then to swing the turntable, together with the tundish 65'into the casting position If desired, the filling of the mold with molten steel may start while the mold is still in the preparation position 61 and the pouring can continue while the turntable and the tundish swing into casting position. If the dummy bar is suitably short and the driven rollers 11 and 12 are appropriately located even the withdrawal of the casting may already start in the preparation position.

FIG. 7 is a section through the mold unit 10 in casting position 4, with the movable section 8 of the roller apron aligned with the fixed section 9. In this embodi ment of the invention the section 8 is equipped with cooling plates 70, guide rollers '73 and driven rollers 11 and H2.

The turntable 60 may be equipped with electrical drive means to generate the mold oscillation, and may also be equipped with hydraulic pumps 72 for the oilhydraulic motors and the hydraulic pressure means for the driven rollers ll and 12. Another drive means (not shown) may be provided for supplying oil for mold lubrication.

FIG. 8 is a section through a mold unit 10' in preparation position 61, with the movable section 8' of the roller apron aligned with a tilted roller table 81 similar to the roller table 22 of FIG. 2. The dummy bar handling means comprises a hoisting means 56 which is adapted to turn the dummy bar horizontally through an angle of 180 before depositing it on a roller table 82 to bring the dummy bar head 83 into the correct position for entry into the section 8'.

FIG. 9 shows the mold 3 in casting position and the mold 3' in preparation position. The inlet and outlet pipes 1 and 91 for the mold coolant are connected to a rotatable ring 92 which is concentric with the turnta ble as and rotates with it. This ring 2 and the coolant supply pipes 93 in the hub 94 constitute a rotary stop valve 95 to prevent loss of coolant. Depending on the position of the turntable 60 and therefore of the ring 92 the inlet and outlet pipes 93 and 91' are either coupled to or disconnected from the supply pipes 93.

We claim as our invention:

l. A continuous casting machine for steel having a casting position and at least one preparation position spaced laterally from said casting position, said machine comprising at least two movable mold units, each of said mold units consisting ofa mold and a section of a roller apron connected thereto and movable therewith, a fixed section ofa roller apron located below and aligned with said casting position, means for transporting said mold units from said casting position to said preparation position and from said preparation position to said casting position with said movable section of the roller apron aligned with said fixed section thereof when said mold unit is in casting position, means for driving at least one roller of each of said movable sec tions of the roller apron, a dummy bar, dummy bar conveyor means spaced laterally from said casting position and aligned with said preparation position to convey said dummy bar to the movable mold unit at the preparation position, and means for feeding said dummy bar from said conveyor means into engagement with the driven roller of the roller apron of said movable mold unit.

2. A continuous casting machine according to claim 1 in which said means for driving at least one roller of each of said movable sections of the roller apron is operable at the preparation position.

3. A continuous casting machine according to claim 1 including inlet and outlet pipes for coolant for the mold, and valve means to control the flow of coolant.

4. A continuous casting machine according to claim 1 in which said dummy bar conveyor includes a tiltable table adapted to be aligned with the movable section of the roller apron.

5. A continuous casting machine according to claim 1 in which when the mold unit is in casting position the end of the movable section of the roller apron which is adjacent the mold is tiltably mounted and the other end bears against a fixed abutment.

6. A continuous casting machine according to claim 1 including at least two tundishes, a kingpin located on the operating side of the mold, said tundishes being mounted for swivelling on said kingpin.

7. A continuous casting machine according to claim 1 including emergency means for cutting the cast strand at a point between said fixed and said movable sections of said roller apron.

8. A continuous casting machine according to claim 1 in which said mold unit includes at least one power generator.

9. A continuous casting machine according to claim 1 in which said means for transporting said mold units is mounted to move horizontally to and from a preparation position located laterally of said casting position.

10. A continuous casting machine according to claim 9 in which said transporting means comprises a car.

11. A continuous casting machine according to claim 1 in which said dummy bar conveyor means is located on either side of and above the cast strand and includes means for transporting said dummy bar laterally and longitudinally.

12. A continuous casting machine according to claim 10 including a platform connected to said car which moves with the car and covers the preparation position when the car moves to the casting position.

13. A continuous casting machine according to claim 1 in which said means for transporting said mold units comprises a turntable.

14. A continuous casting machine according to claim 13 in which said turntable transports said mold units to a common preparation position.

15. A continuous casting machine according to claim 13 including two tundishes located above said turntable, and means for mounting said tundishes to swivel on the same axis as that on which said turntable turns.

16. A continuous casting machine according to claim 12 including a tundish mounted on said platform and moving with said platform.

17. A continuous casting machine according to claim 13 in which two mold units are mounted on each of two adjacent turntables.

18. A continuous casting machine according to claim 11 in which said lateral transporting means comprises a roller table mounted on a car.

19. A continuous casting machine according to claim 15 in which said tundishes turn with said turntable as said turntable turns.

Claims

1. A continuous casting machine for steel having a casting position and at least one preparation position spaced laterally from said casting position, said machine comprising at least two movable mold units, each of said mold units consisting of a mold and a section of a roller apron connected thereto and movable therewith, a fixed section of a roller apron located below and aligned with said casting position, means for transporting said mold units from said casting position to said preparation position and from said preparation position to said casting position with said movable section of the roller apron aligned with said fixed section thereof when said mold unit is in casting position, means for driving at least one roller of each of said movable sections of the roller apron, a dummy bar, dummy bar conveyor means spaced laterally from said casting position and aligned with said preparation position to convey said dummy bar to the movable mold unit at the preparation position, and means for feeding said dummy bar from said conveyor means into engagement with the driven roller of the roller apron of said movable mold unit.