Lateral strand guide for a continuous casting installation

Abstract

The present invention is in the field of continuous casting technology and describes a lateral strand guide for a continuous casting plant. A device for supporting slab-shaped strands with a large casting thickness, a continuous casting plant, and a method for operating a continuous casting plant are described. Downstream of the mold, at least one first roller carrier with rollers and one second roller carrier with rollers are arranged on the narrow sides, wherein the axes of rotation of the rollers of the respective roller carriers have a fixed spatial relationship to the roller carrier. The roller carriers can each perform a translational movement and / or a rotational movement, which is executed by at least one actuator. Furthermore, a method for operating a continuous casting plant is described.The actuation force of the actuators is controlled / regulated such that the supporting force applied to the narrow side by the respective rollers is greater than the compressive force resulting from ferrostatic pressure in the strand. Furthermore, the position of the actuators and / or the inclination angle of the roller carriers are controlled / regulated.

Description

field of technology

[0001] The present invention is in the field of continuous casting technology and describes a device for supporting slab-shaped strands, particularly with a casting thickness of at least 300 mm, preferably at least 400 mm. A strand to be cast has opposing broad sides and opposing narrow sides, wherein a mold comprises narrow-side inserts with narrow side walls and broad-side walls.

[0002] Viewed in one direction of casting, the strand is guided and supported on the opposite broad sides after the mold. State of the art

[0003] In continuous casting of slabs, narrow-side bulging frequently occurs, especially with large casting thicknesses. This involves a bulging of the still thin and relatively weak strand shell in the area of ​​the narrow sides of the casting strand. This can lead to quality problems in the casting product.

[0004] In particular, grooves and associated surface defects can form in the edge area of ​​the broad sides of the slabs. Furthermore, longitudinal internal cracks can occur near the edges.

[0005] Larger casting thicknesses, higher casting speeds, low strand cooling, and soft steel grades promote these undesirable effects.

[0006] Essentially, the problems and undesirable effects described stem from insufficient support or guidance of the narrow sides of the slab. According to current best practices, this support is usually provided by four or five foot rollers attached to the mold. A typical support length—that is, the length of the area below the mold where the narrow side of the slab being cast is supported by rollers—is typically less than 1 meter in conventional slab casting plants. Particularly when casting ultra-thick slabs, this short support length has proven to lead to quality problems.

[0007] CN2024115338378B describes a mold narrow-side foot roller mechanism and a control method. The mold narrow-side foot roller mechanism includes a sliding mechanism for supporting and moving the foot roller support.

[0008] The rollers of the described mold narrow-side foot roller mechanism have a fixed spatial relationship to each other on each narrow side with respect to their axes of rotation. The longer such a mold narrow-side foot roller mechanism is, the less able it is to follow a curved extrusion contour. This is the case, for example, with changes in casting width.

[0009] AT304786B describes a device for continuous casting, wherein the rollers or pairs of rollers located on the two narrow sides of the slab-shaped strand are arranged from directly below the mold to a distance from the casting surface which corresponds to 1.5 to 3 times the mold length and are hydraulically or spring-loaded displaceable transversely to the strand.

[0010] The lateral guide rollers of this typeface are individually driven and not grouped together with a common drive. This results in considerable design complexity.

[0011] In contrast, for continuous casting plants for long products (e.g., pre-casting blocks), it has been found that even with large rectangular and square casting cross-sections, the described quality problems do not occur when using correspondingly large support lengths. Summary of the invention

[0012] The object of the present invention is to provide a device for supporting slab-shaped strands, a continuous casting plant, and a method for operating a continuous casting plant.

[0013] According to the invention, at least one first roller carrier with at least three rollers, preferably at least four rollers, particularly preferably at least five rollers, is arranged on the narrow sides after the mold. Furthermore, a second roller carrier with at least three rollers, preferably at least four rollers, particularly preferably at least five rollers is arranged.

[0014] The rotation axes of the rollers of the respective roller carrier have a fixed spatial relationship to the roller carrier, with the roller carriers being arranged relative to the mold such that each roller carrier can perform a translational and / or a rotational movement. This movement is executed by at least one actuator.

[0015] The rollers of the lateral strand guide must adapt to the local contour of the strand when viewed along the casting direction. Such adaptation is necessary, for example, when the casting width changes. In addition to rotating the rollers around their own axis of rotation, this requires movement along the lateral strand contour. Several rollers mounted on a roller carrier perform this movement simultaneously.

[0016] When the casting width changes, the strand contour, viewed along the casting direction, is not straight but curved. Therefore, if more than two rollers are arranged on a roller carrier such that their axes of rotation have a fixed spatial relationship to each other, at least one roller will lift off the strand contour to a greater or lesser degree, and / or at least one roller will press against it to a greater or lesser degree. This effect is more pronounced the more rollers are on a roller carrier, or the greater the curvature of the strand contour.

[0017] Therefore, it is particularly advantageous to use multiple roller supports when dealing with larger lateral support lengths. This provides additional degrees of freedom for the lateral strand guidance and allows for more uniform guidance of the lateral strand contour with regard to the lifting and / or pressing of individual rollers.

[0018] Two roller supports per narrow side lead to significant quality improvements, especially on the narrow sides of the slabs to be cast, at the specified casting thicknesses, and the associated design effort does not conflict with economic considerations.

[0019] In a preferred embodiment, at least one roller carrier has a support adjustment such that at least one roller is displaceable relative to another roller of this roller carrier in the direction of the axes of rotation; preferably, every second roller is displaceable relative to an immediately adjacent roller, and this displacement is adjustable.

[0020] In a further preferred embodiment, the translational motion comprises a first translational motion defined by a respective vector in the broadside direction, and the rotational motion comprises a first rotational motion defined by a respective vector substantially normal to the respective broadside.

[0021] In a further preferred embodiment, the translational movement comprises a second translational movement defined by a vector substantially normal to the respective broad side, and the rotational movement comprises a second rotational movement defined by a vector along the respective casting direction (8).

[0022] The second translational movement describes a displacement of the roller supports in the thickness direction of the strand. This displacement can be adjusted, for example, when changing the casting thickness. Thus, the support of the strand shell at the narrow sides can be centered regardless of the casting thickness.

[0023] The second rotational movement of the roller supports can compensate for twisting of the narrow sides of the strand around an axis in the direction of the respective casting direction. This movement can be self-aligning through a suitably articulated suspension of the roller supports, ensuring uniform support of the narrow side.

[0024] In a further preferred embodiment, at least one of the rollers, preferably all rollers, comprises at least three roller balls arranged side by side in the direction of rotation of the respective roller.

[0025] In another preferred embodiment, at least part of the roller carrier comprises spray nozzles.

[0026] In a further preferred embodiment, the first roller carriers are pivotally connected to a narrow-side insert of the mold.

[0027] In a further preferred embodiment, the second roller supports are pivotally connected to the first roller supports on both narrow sides.

[0028] In another preferred embodiment, the second roller carriers are coupled to a continuous casting segment below the mold, as seen in the casting direction.

[0029] In a further preferred embodiment, the first translational and / or rotational movement of the first roller carrier is carried out by an actuator, and the actuator is arranged between the first roller carrier and a narrow side projection or between the first roller carrier and a continuous casting segment.

[0030] In a further preferred embodiment, the first translational and / or the first rotational movement of the second roller carrier is each carried out by two actuators.

[0031] In another preferred embodiment, the actuators are hydraulic cylinders and / or electromechanical actuators. Preferably, at least one actuator has a displacement measuring system and / or at least one roller carrier has an inclinometer.

[0032] In a further preferred embodiment, the support length from a lower edge of the mold to a last roller of the second roller carrier, viewed in the casting direction, is at least 1 m, preferably at least 1.8 m, and particularly preferably at least 2.5 m.

[0033] Furthermore, the present invention comprises a continuous casting plant, including the described device in the described embodiments.

[0034] Furthermore, the present invention comprises a method for operating a continuous casting plant which is operated in a first or second normal operation, or a special operation.

[0035] The first normal operation includes regulating / controlling the actuation force of the actuators to a value specified by a higher-level plant control system such that a support force applied to the narrow side by the respective rollers is greater than a pressure force resulting from a ferrostatic pressure in the strand multiplied by a corresponding reference area.

[0036] The second normal operation includes regulating / controlling the position of the actuators and / or the tilt angle of the roller carriers to a value specified by a higher-level plant control system, such that the rollers of the roller carriers follow a width profile of the strand in such a way that at least one roller per roller carrier is in contact with the respective narrow side of the strand.

[0037] The special operating mode involves completely retracting the roller carriers into a parked position. This occurs particularly during the operating modes of casting start, casting end, distributor change, and width adjustment. Furthermore, the special operating mode can be activated if an alarm is triggered indicating an increased risk of a breakthrough. Brief description of the drawings

[0038] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of an exemplary embodiment, which is explained in more detail in conjunction with the drawings. These drawings show: Fig. 1 two sectional views of a mold with a device for supporting slab-shaped strands below the mold, as well as a top view of the mold or a casting surface of the strand to be cast, Fig. 2 bis Fig. 4 Three embodiments of a device for supporting slab-shaped strands on their narrow sides, comprising a first roller carrier with four rollers and a second roller carrier with four rollers, Fig. 5 two top views, one side view and one front view of a roller support with adjustable support, Fig. 6 a side view of a continuous casting mold with a device for supporting slab-shaped strands below the mold, as well as a sectional view of the strand to be cast with a front view of two roller carriers, Fig. 7 Two sectional views of the strand to be cast for different casting thicknesses and front views of roller carriers with support adjustment, Fig. 8 two sectional views of the strand to be cast for different casting thicknesses and front views of roller supports that support the strand in the middle on the narrow side, Fig. 9 a front view of a roller carrier with a roller, consisting of a roller bale and Fig. 10 A front view of a roller carrier with one roller, consisting of three roller bales. Description of the embodiments

[0039] Fig. 1 Figure 1 shows an embodiment of the invention in the form of two sectional views of a mold 2 with a device for supporting slab-shaped strands 1 below the mold 2, as well as a top view of the mold 2 and a casting surface of the strand 1 to be cast. The broad sides 3 and narrow sides 4 of the strand 1 are also shown. Narrow side walls 6, narrow side inserts 5, and broad side walls 7 are components of the mold 2. A casting direction 8 and a width direction 9 perpendicular to it serve for orientation on the strand 1. Support of the narrow sides 4 in a support area 20 comprises first roller carriers 10 and second roller carriers 12, each comprising four rollers 11. The roller carriers can each perform a first rotational movement 23 and / or a first translational movement 24.

[0040] Fig. 2 shows as an embodiment of the invention as a section of Fig. 1 A device for supporting slab-shaped strands 1 on a narrow side 4, comprising a first roller support 10 with four rollers 11 and a second roller support 12 with four rollers 11, wherein the first roller support 10 is connected to a narrow-side insert 5 of the mold via the hinged connection 17. Furthermore, the first roller support 10 is connected to a first actuator 15, and the second roller support 12 is connected to two second actuators 15a. The first actuator 15, which is connected to the first roller support 10, is also connected to the narrow-side insert 5 of the mold 2. Since the second roller support 12 is not hinged to the first roller support 10, its vertical position is coupled to a continuous casting segment below the mold.

[0041] Fig. 3 shows as an embodiment of the invention as a section of Fig. 1 A device for supporting slab-shaped strands 1 on a narrow side 4, comprising a first roller carrier 10 with four rollers 11 and a second roller carrier 12 with four rollers 11, wherein the first roller carrier 10 is connected to a narrow-side insert 5 of the mold via the hinged connection 17. Furthermore, the first roller carrier 10 is connected to a first actuator 15, and the second roller carrier 12 is connected to two second actuators 15a. The first actuator 15, which is connected to the first roller carrier 10, is also connected to a continuous casting segment below the mold. Since the second roller carrier 12 is not hinged to the first roller carrier 10, its vertical position is coupled to a continuous casting segment below the mold. A displacement measuring system 25 of an actuator 15 is also shown.

[0042] Fig. 4 shows as an embodiment of the invention as a section of Fig. 1 A device for supporting slab-shaped strands 1 on a narrow side 4, comprising a first roller carrier 10 with four rollers 11 and a second roller carrier 12 with four rollers 11, wherein the first roller carrier 10 is connected to a narrow-side insert 5 of the mold via the hinged connection 17. Furthermore, the second roller carrier 12 is connected to two second actuators 15a. The second roller carrier 12 is hinged to the first roller carrier 10. Thus, its vertical position is coupled to the first roller carrier 10 and therefore to the mold.

[0043] Fig. 5 Figure 1 shows an embodiment of the invention, comprising two top views, a side view, and a front view of a roller carrier with a support adjustment mechanism 16. The two top views illustrate different settings of the support adjustment mechanism 16. Two rollers 11 are displaced along their axes of rotation 26 relative to two other rollers 11. In this way, the roller carrier 10, 12 can be adapted to different casting thicknesses of the strand. The second rotational movement 13 is also shown in the front view of the roller carrier 10, 12.

[0044] Fig. 6 Figure 1 shows a side view of a mold 2 with a device for supporting slab-shaped strands 1 below the mold 2 as an embodiment of the invention. The strand 1, which runs in an arc below the mold 2, is visible, as are a first roller support 10 and a second roller support 12 for guiding and supporting a narrow side 4 of the strand 1. Due to the curvature of the strand 1, the originally rectangular casting cross-section deforms into a trapezoid. This causes the narrow sides 4 of the strand 1 to twist about an axis in the direction of the respective casting direction. The roller supports 10 and 12 can follow this twist as a second rotational movement 13, thus ensuring uniform support of the narrow side 4.

[0045] Fig. 7 Figure 1 shows two cross-sectional views of the strand 1 to be cast for different casting thicknesses as an embodiment of the invention. For the sake of simplicity, a section of a rectangular casting cross-section is shown. Furthermore, two front views of roller carriers 10, 12 with support adjustment 16 are shown. This support adjustment 16 allows the roller carrier 10, 12 to be adapted to different casting thicknesses of the strand 1.

[0046] Fig. 8 Figure 1 shows two cross-sectional views of the strand 1 to be cast for different casting thicknesses as an embodiment of the invention. For the sake of simplicity, a section of a rectangular casting cross-section is shown. Furthermore, two front views of roller supports are shown, each supporting the strand 1 centrally on its narrow side 4. This central support is made possible by the second translational movement 14 of the roller support 10, 12.

[0047] Fig. 9 shows a front view of a roller carrier 10, 12 with a roller 11, consisting of a roller bale 27.

[0048] Fig. 10 shows a front view of a roller carrier 10, 12 with a roller 11, consisting of three roller bales 27.

[0049] Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by the person skilled in the art without leaving the scope of protection of the invention. Reference symbol list

[0050] 1 Strand 2 Mold 3 Broad sides 4 Narrow sides 5 Narrow side insert 6 Narrow side wall 7 Broad side wall 8 Casting direction 9 Broad direction 10 First roller carrier 11 Roller 12 Second roller carrier 13 Second rotary movement 14 Second translational movement 15 First actuator 15a Second actuators 16 Support adjustment 17 Articulated connection 20 Support area 23 First rotary movement 24 First translational movement 25 Position measuring system 26 Rotation axis 27 Roller ball

Claims

1. Device for supporting slab-shaped strands (1), in particular with a casting thickness of at least 300 mm, preferably at least 400 mm, wherein a strand (1) to be cast has opposite broad sides (3) and opposite narrow sides (4), wherein a mold (2) comprises narrow side inserts (5) with narrow side walls (6) and broad side walls (7), and the strand (1), viewed in a casting direction (8), is guided and supported after the mold (2) on the opposite broad sides (3), characterized by thatat least one first roller carrier (10) with at least three rollers (11), preferably at least four rollers (11), particularly preferably at least five rollers (11), is arranged on the narrow sides (4) of the mold (2), and a second roller carrier (12) with at least three rollers (11), preferably at least four rollers (11), particularly preferably at least five rollers (11), is arranged, wherein the axes of rotation (26) of the rollers (11) of the respective roller carrier (10, 12) have a fixed local reference to the roller carrier (10, 12), and wherein the roller carriers (10, 12) are arranged relative to the mold (2) such that that The roller carriers (10,12) can each perform a translational movement (14, 24) and / or a rotational movement (13, 23), which is performed by at least one actuator (15, 15a).

2. Device according to one of the preceding claims, wherein at least one roller carrier (10, 12) has a support adjustment (16) such that at least one roller (11) is displaceable relative to another roller (11) of this roller carrier (10, 12) in the direction of the axes of rotation (26), preferably every second roller (11) is displaceable relative to an immediately adjacent roller (11), and this displacement is adjustable.

3. Device according to one of the preceding claims, wherein the translational movement (14, 24) comprises a first translational movement (24) defined by a respective vector in a width direction (9), and the rotational movement (13, 23) comprises a first rotational movement (23) defined by a respective vector substantially normal to the respective width (3).

4. Device according to one of the preceding claims, wherein the translational movement (14, 24) comprises a second translational movement (14) defined by a vector substantially normal to the respective broad side (3), and the rotational movement (13, 23) comprises a second rotational movement (13) defined by a vector along the respective casting direction (8).

5. Device according to one of the preceding claims, wherein at least one of the rollers (11), preferably all rollers (11), comprises at least three roller balls (27) arranged side by side in the direction of rotation of the respective roller (11).

6. Device according to one of the preceding claims, wherein at least a part of the roller carriers (10, 12) comprises spray nozzles.

7. Device according to one of the preceding claims, wherein the first roller carriers (10) are articulated to a narrow side insert (5) of the mold (2).

8. Device according to one of the preceding claims, wherein the second roller carriers (12) are pivotally connected to the first roller carriers (10) on both narrow sides (4).

9. Device according to one of claims 1 - 7, wherein the second roller carriers (12) are coupled to a continuous casting segment below the mold, as seen in the direction of casting.

10. Device according to claim 9, wherein the first translational movement (24) and / or the first rotational movement (23) of the first roller carrier (12) is performed by a first actuator (15), and the first actuator (15) is arranged between the first roller carrier (10) and a narrow side extension (5) or between the first roller carrier (10) and a continuous casting segment.

11. Device according to one of the preceding claims, wherein the first translational (24) and / or the first rotational movement (23) of the second roller carrier (12) is each performed by two second actuators (15a).

12. Device according to one of claims 10 - 11, wherein the actuators (15, 15a) are hydraulic cylinders and / or electromechanical actuators, preferably at least one actuator (15, 15a) has a displacement measuring system (25) and / or at least one roller carrier (10, 12) has an inclinometer.

13. Device according to one of the preceding claims, wherein a support length (20) from a lower edge of the mold (2) to a last roller (11) of the second roller carrier (12), seen in the casting direction (8), is at least 1 m, preferably at least 1.8 m, particularly preferably at least 2.5 m.

14. Continuous casting plant comprising a device according to one of the preceding claims.

15. A method for operating a continuous casting plant according to claim 14, which is operated in a first or second normal operation, or a special operation, wherein the first normal operation comprises regulating / controlling the actuation force of the actuators (15, 15a) to a value specified by a higher-level plant control system such that a support force applied to the narrow side (4) by the respective rollers (11) is greater than a compressive force resulting from a ferrostatic pressure in the strand (1) multiplied by a corresponding reference area, and the second normal operation comprises regulating / controlling a position of the actuators (15, 15a) and / or the inclination angle of the roller carriers (10, 12) to a value specified by a higher-level plant control system such that the rollers (11) of the roller carriers (10, 12) follow a width profile of the strand (1) such that at least one roller (11) per roller carrier (10, 12)12) is in contact with the respective narrow side (4) of the strand (1), and the special operation includes a complete retraction of the roller carriers (10, 12) into a parking position.

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