JP2018034181A - Slab continuous casting device - Google Patents

Abstract

A slab ejection direction from an immersion nozzle is stabilized. A base 11 is disposed between a stopper-type flow rate adjusting mechanism 10 and an immersion nozzle 6. The nozzle replacement holding mechanism 20 moves the immersion nozzle 6 through the moving connection space D provided in the base 11 when replacing the nozzle, and moves the immersion nozzle 6 disposed in the molten metal flow path upward during operation. Lift to maintain the connectivity of the immersion nozzle 6. The rotation mechanism rotates the base 11. The fixing mechanism 30 urges the immersion nozzle 6 disposed in the molten metal flow path by the nozzle replacement holding mechanism 20 in a direction perpendicular to the moving direction of the immersion nozzle at the time of nozzle replacement in the moving connection space D. Press against the inner wall of D and fix. [Selection] Figure 3

Description

  The present invention relates to a slab continuous casting apparatus, and more particularly to a slab continuous casting apparatus that swirls and stirs molten metal in a mold for slab by arbitrarily changing the discharge angle of molten metal during casting.

  In recent years, in order to mass-produce ingots (also called slabs) of steel or various alloys, molten metal in a molten state is continuously poured into a water-cooled mold and the solidified ingot is gradually added to the ingot. It is common to use a so-called “continuous casting method” that is extracted from a mold.

  In order to obtain an ingot having excellent quality with less non-metallic inclusions and less segregation of components by this continuous casting, it is important to appropriately stir the molten metal in the course of solidification. Furthermore, in molten metal stirring in a slab having a large cross-sectional area and a large cross-sectional aspect ratio (for example, the ratio of the length of the long side wall ÷ the length of the short side wall is 5 or more), Unlike slabs with a small cross-sectional area and a substantially square cross-section, problems such as the occurrence of center segregation and cracks in the center section and deterioration of workability are likely to occur, and the molten metal can be stirred more stably. It has been demanded.

  In recent years, with the extension of the life of immersion nozzles, etc., the service life of immersion nozzles can withstand casting of multiple pans, and it is possible to continuously cast slabs with different steel grades and cooling mold widths It became possible. Various configurations for appropriately stirring the molten metal have been proposed in the past, but they are still insufficient for dealing with changes in the width and thickness of the mold.

  The applicant of the present application discloses a platform (hereinafter referred to as a base) on which a mechanism for connecting an immersion nozzle to a slide nozzle mechanism (hereinafter referred to as a nozzle replacement holding mechanism) is mounted at a predetermined angle together with the immersion nozzle. An apparatus for continuous casting of a slab provided with a rotating mechanism for rotating is proposed. With this configuration, the discharge direction of the molten metal from the discharge port at the lower end of the immersion nozzle is held in the target direction in the long side direction to obtain a swirling flow, and also corresponds to the length and thickness of the long side The rotation angle can be maintained.

  FIG. 1 is a cross-sectional view of a slab continuous casting apparatus disclosed in Patent Document 1, and FIG. 2 is a bottom view.

  A conventional slab continuous casting apparatus has a stopper-type flow rate adjusting mechanism that adjusts the amount of molten metal flowing into the mold, and an immersion nozzle that guides the molten metal from the stopper-type flow rate adjusting mechanism to the mold. A nozzle replacement holding mechanism that replaces a used immersion nozzle and an unused immersion nozzle is provided. The apparatus disclosed in Patent Document 1 has the same configuration, but the apparatus disclosed in Patent Document 1 further includes a nozzle rotation mechanism described below.

  As is well known, the stopper-type flow rate adjusting mechanism 10 has a stopper 3 inserted from above into the molten steel of the tundish 1 with respect to the nozzle hole of the upper nozzle 2 provided at the bottom (feather) of the tundish 1. By moving up and down, the distance between the stopper 3 and the upper nozzle 2 is changed. As a result, the flow rate of the molten metal passing between the stopper 3 and the upper nozzle 2 can be adjusted and supplied to the immersion nozzle 6. 1 shows a configuration in which the lower nozzle 4 is disposed between the upper nozzle 2 and the immersion nozzle 6, but the lower nozzle 4 is immersed in the lower end of the upper nozzle 2 without the lower nozzle 4 interposed. In some cases, the nozzle 6 is directly arranged.

  The nozzle replacement holding mechanism 20 is incorporated in the base 11 disposed below the housing 5 that supports the upper nozzle 2 below the tundish 1.

  The base 11 is located on both sides of a direction (hereinafter, sometimes referred to as a left-right direction or a left-right direction) perpendicular to the direction of movement of the immersion nozzle 6 (hereinafter referred to as the nozzle movement direction: arrow direction in FIG. 2) when the immersion nozzle is replaced. Two pieces 11a and 11b are connected by a connecting piece 11c to be integrated. The center part of the left and right pieces 11a, 11b can move the immersion nozzle 6 when the immersion nozzle 6 is replaced, and is connected to the lower nozzle 4 when the immersion nozzle 6 is fixed (operating). It is a space that can be connected (hereinafter referred to as a moving connection space D). The left and right widths of the moving connection space D correspond to the left and right widths of the flange 15 at the upper end of the immersion nozzle 6, and a slide guide 14 is provided on the inner side along the nozzle movement direction. The flange 15 at the upper end of the immersion nozzle 6 is pressed and held against the lower surface of the lower nozzle 4 in the following configuration.

  On the lower surfaces of the left and right pieces 11a and 11b of the base 11 and on the left and right sides of the moving connection space D, the tips are positioned along the nozzle moving direction and on the lower surface of the flange 15 of the immersion nozzle 6. A plurality of clampers 13 are supported by clamper pins 16. A coil spring 12 attached to the base 11 is provided at the rear end of the clamper 13, and the tip of the clamper 13 is biased upward. Thus, the lower side of the flange 15 of the immersion nozzle 6 is biased upward at the tip of the clamper 13 so that the upper end surface of the immersion nozzle 6 is in close contact with the lower surface of the lower nozzle 4.

  Moreover, this slab continuous casting apparatus can replace the used immersion nozzle 6e and the unused immersion nozzle 6n by the nozzle replacement holding mechanism 20. The unused immersion nozzle 6n inserted from the guide rail 17 on the upstream side in the nozzle movement direction by the nozzle replacement holding mechanism 20 moves toward the downstream side in the movement direction, and the used immersion nozzle 6e is moved to the downstream guide. It pushes out to the rail 17. At this time, the connecting piece 11c of the base 11 is configured not to interfere with the movement of the immersion nozzle 6, as shown in FIG.

  In a normal slab continuous casting apparatus, the base 11 is fixed to the housing 5. However, in the apparatus disclosed in Patent Document 1 on which the present application is based, the rotation mechanism allows a predetermined angle of rotation. It has come to be.

  That is, the base 11 is suspended from the housing 5 by the support guide 21 and the support guide roller 22 so as to be rotatable about the central axis P of the immersion nozzle 6, and the drive device fixed to the housing 5 in this state. By being driven by the (hydraulic cylinder) 23, it can be rotated by a predetermined angle. Thereby, the immersion nozzle 6 held by the nozzle replacement holding mechanism 20 also rotates, and the discharge direction of the molten metal from the discharge hole can be changed according to the situation.

Japanese Patent Laid-Open No. 2006-131982

  When the slab continuous casting apparatus is configured as disclosed in Patent Document 1, the discharge direction of the immersion nozzle 6 can be arbitrarily changed. At this time, ideally, it is desirable that the ejection direction is changed following the movement of the driving device 23 accurately. However, since the immersion nozzle 6 and the lower nozzle 4 are designed to slide while ensuring gas sealing properties, the sliding surface receives frictional resistance when the base 11 rotates, and the immersion nozzle 6 Will receive stress in the opposite direction. On the other hand, when the immersion nozzle 6 is replaced, the unused immersion nozzle 6 needs to be smoothly inserted between the left and right slide guides 14 (moving connection space D). 14 has a slight clearance. If this clearance is reduced, there arises a problem that the immersion nozzle 6 cannot be inserted between the slide guides 14 (pieces 11a and 11b) due to variations in manufacturing of the flange size of the immersion nozzle 6 and the like.

  The present invention has been proposed in view of the above-described conventional circumstances, and can smoothly insert the immersion nozzle between the slide guides (moving connection space D) and change the discharge direction. It is an object of the present invention to provide a device for correctly following the movement of a drive device.

  In order to achieve the above object, the present invention employs the following technical means. First, the present invention is based on a slab continuous casting apparatus that supplies molten metal to a mold from a tundish through a stopper-type flow rate adjusting mechanism and an immersion nozzle. The slab continuous casting apparatus according to the present invention includes a base, a nozzle replacement holding mechanism, a rotation mechanism, and a fixing mechanism. The base is disposed between the stopper-type flow rate adjusting mechanism and the immersion nozzle. The nozzle replacement holding mechanism moves the immersion nozzle through a moving connection space provided in the base when the nozzle is replaced, and lifts the immersion nozzle disposed in the molten metal flow path upward during operation. Maintain connectivity. The rotation mechanism rotates the base. The fixing mechanism urges the immersion nozzle arranged in the molten metal flow path by the nozzle replacement holding mechanism in a direction perpendicular to the moving direction of the immersion nozzle during nozzle replacement in the moving connection space, and presses it against the inner wall of the moving connection space. And fix.

  The fixing mechanism constitutes the moving connection space, and an elastic material or an actuator is disposed on one of the two pieces of the base arranged opposite to each other, and is held in the movement connection space by the elastic material or the actuator. It is possible to adopt a configuration in which the position of the immersion nozzle is fixed by energizing one side surface of the flange of the immersion nozzle and pressing the other side surface against the other piece. Moreover, an elastic material or an actuator can also be provided in both of the above-mentioned two pieces.

  A fixing member in a direction parallel to the moving direction of the immersion nozzle is attached to the tip of the elastic material or actuator described above, and a configuration in which the fixing member presses one side surface of the flange of the immersion nozzle can be employed. The contact surface of the fixed member with the immersion nozzle is provided with protrusions protruding in the direction perpendicular to the movement direction at both ends in the movement direction of the immersion nozzle, and the protrusions are tapered upstream and downstream in the movement direction. It can be set as the structure provided.

  The urging force of the fixing mechanism is desirably 300 to 5000 N (30 to 500 kgf).

  With the above configuration, during casting, when the immersion nozzle is rotated by a predetermined angle by the rotation mechanism so as to change the discharge direction of the immersion nozzle, the immersion nozzle is fixed by the fixing mechanism. The discharge direction can be changed.

  Moreover, by setting the pressing force in the fixing mechanism to a force (300 to 5000 N (30 to 500 kgf)) that allows the fixing member to escape in the direction opposite to the pressing direction when replacing the immersion nozzle, The immersion nozzle can be easily replaced.

  Furthermore, during casting, the discharge flow from the immersion nozzle can be directed to a specific direction in any desired direction, giving a swirl flow to the molten metal, and further, the discharge angle due to the accumulation of inclusions in the discharge holes. Appropriate discharge angle can be ensured even when there is a change or a change in the thickness or width of the mold.

Sectional drawing which shows an example of the conventional slab continuous casting apparatus provided with a stopper type flow control mechanism Bottom view showing an example of a conventional slab continuous casting apparatus equipped with a stopper type flow rate adjusting mechanism Sectional drawing which shows an example of the apparatus for slab continuous casting in one Embodiment of this invention The bottom view which shows an example of the apparatus for slab continuous casting in one Embodiment of this invention Sectional drawing which shows an example of the fixing mechanism in one Embodiment of this invention Sectional drawing which shows an example of the fixing member and slide guide in one Embodiment of this invention

  FIG. 3 is a front view showing an example of an apparatus for continuous slab casting in one embodiment of the present invention, and FIG. 4 is a bottom view. FIG. 5 is a cross-sectional view showing an example of a fixing mechanism in one embodiment of the present invention.

  In the prior art shown in FIG. 1, the base 11 of the nozzle replacement holding mechanism 20 is held in the housing 5 by the support guide 21 and the support guide roller 22. In the present embodiment, the following configuration is used.

  That is, as shown in FIGS. 3 to 5, at the upper end of the base 11, a protrusion that protrudes outward in the radial direction over the entire circumference in the circumferential direction (circumferential direction of a circle centering on the central axis P of the immersion nozzle 6) A portion 25 is provided. The support guide 21 is fixed to the lower surface of the housing 5 in a state where a part of the support guide 21 is engaged with the protruding portion 25 (a state where the upper surface of the support guide 21 supports the lower surface of the protruding portion 25). And the base 11 can be rotated because the lower surface of the protrusion part 25 and the upper surface of the support guide 21 slide mutually. As in the prior art, the rotational force applied to the base 11 is applied to the base 11 via the lever 27 from the hydraulic cylinder 23 fixed to the housing 5.

  Further, as shown in FIG. 3, the width in the left-right direction of the moving connection space D of the portion covering the lower nozzle 4 at the upper center of the base 11 is wider than the width of the flange 15 of the immersion nozzle 6.

  Then, the fixing mechanism 30 with which the apparatus for slab continuous casting of this embodiment is provided is demonstrated. As shown in FIGS. 3 and 5, there is a moving connection space on the inner side (inner wall) of the moving connection space D of one piece 11 a of the left and right two pieces 11 a and 11 b of the base 11 that is the platform of the nozzle replacement holding mechanism 20. Spring holes 33a are provided at two locations on the upstream side and the downstream side in the nozzle movement direction (arrow direction in FIG. 5) toward D. A coil spring 33 is inserted into the spring hole 33a by a bolt 32 (a leg of the fixing member 31) inserted in the spring hole 33a. The two coil springs 33 are provided with a fixing member 31 over the nozzle movement direction. As shown in FIG. 5, a coil spring 33 is fitted into the bolt 32, and the fixing member 31 is mounted with a margin of movement so that it can move with a certain width in the left-right direction. As a result, the fixing member 31 is biased in the left-right direction (here, the direction toward the other piece 11b of the base 11).

  On the other hand, on the inner side (inner wall) of the moving connection space D of the piece 11b of the base 11 on the side facing the side where the fixing member 31 is mounted, the slide guide 14 is formed integrally with the base 11b as in the conventional case. Thus, when the immersion nozzle 6 is inserted into the moving connection space D, the fixing member 31 moves the side surface of the flange 15 of the immersion nozzle 6 in the left-right direction, that is, on the inner side (inner wall) of the opposing piece 11b. It comes in pressure contact with the slide guide 14. Thus, the immersion nozzle 6 rotates at an angle corresponding to the movement of the driving device 23 when the immersion nozzle 6 rotates.

  Further, at the time of replacement of the immersion nozzle, the immersion nozzle 6 is pushed in the moving direction by the nozzle replacement cylinder 29, and at this time, the fixing member 31 only holds the immersion nozzle 6 with an appropriate force as disclosed below. Thus, it is possible to escape in the direction opposite to the pressing direction, and the immersion nozzle 6 can be easily replaced.

  The number of the bolts 32 that are the legs of the fixing member is two in FIG. 5, but may be one or three or more. Moreover, although the case where the coil spring 33 was used was illustrated in FIG. 5, you may utilize arbitrary elastic materials, such as not only the coil spring 33 but a leaf | plate spring, a bamboo shoot spring, and a torsion spring. Furthermore, the fixing member 31 may be biased using various actuators. As an example of the actuator, a hydraulic cylinder, a hydraulic cylinder, a pneumatic cylinder, a solenoid valve, or the like can be used.

  The pressing force for pressing the flange 15 of the immersion nozzle 6 by the fixing mechanism 30 is preferably 300 to 5000 N (30 to 500 kgf). If it is less than 300 N, when the drive device 23 for changing the discharge direction rotates the base 11, it receives frictional resistance on the sliding surface with the lower nozzle 4 and can oppose stress acting in the direction opposite to the drive direction. This is not preferable because the immersion nozzle cannot be fixed. If it is larger than 5000 N, even if the immersion nozzle 6 is pushed in the nozzle movement direction when replacing the immersion nozzle, the fixing member 31 does not escape and the nozzle cannot be replaced. More preferably, it is 1000-3000N.

  FIG. 6 is an enlarged view of the fixing member 31. Protrusions 37 are preferably provided on the upstream side and the downstream side of the fixing member 31. Further, it is preferable to provide tapers 37 a and 37 b on the further upstream side and the downstream side of the protrusion 37. By the tapers 37a and 37b, a spread is provided between the fixing member 31 on the entry side (retreat side) of the immersion nozzle 6 and the slide guide 14, and enters from the upstream side in the movement direction (downstream in the movement direction). The flange 15 of the immersion nozzle 6 (retreats to the side) smoothly enters (retreats) between the fixing member 31 and the slide guide 14.

  The inner contact surface 37c (the surface that contacts the flange 15 during operation) when viewed from the center of the fixing member 31 is shaped to follow the outer periphery of the flange 15 of the immersion nozzle 6, and the immersion nozzle 6 is replaced when the immersion nozzle is replaced. The outer periphery of the flange 15 is fitted into the contact surface 37c, and the immersion nozzle 6 is firmly fixed.

  The protrusions 37 provided at both ends of the fixing member 31 also have an effect of preventing the immersion nozzle 6 from shifting in the moving direction when the base 11 is rotated. For this reason, the distance between the protrusion 37 and the protrusion 37 is set to a value close to the length of the flange 15 of the immersion nozzle 6 in the moving direction. The shape of the abutment surface 37c between the protrusions 37 is not particularly defined, but when the corner of the outer periphery of the flange 15 is the R surface, the shape along the R surface is preferable, and in the case of C processing, along the C processing. It is preferable to use a different shape.

  The height of the protrusion 37 is preferably 1 to 5 mm. If it is larger than 5 mm, the escape of the fixing member 31 becomes too large, and the immersion nozzle 6 cannot be exchanged smoothly.

  When an unused immersion nozzle 6n is set on the guide rail 17 of the nozzle replacement holding mechanism 20, there is a slight clearance between the upstream end of the slide guide 14 in the nozzle moving direction and the downstream end of the flange 15 of the immersion nozzle 6. However, it is easy to set the immersion nozzle 6 and the immersion nozzle 6 is easy to move. On the other hand, when the immersion nozzle 6 is held at the use position during operation, the center position of the immersion nozzle 6 is preferably located at a predetermined location, whereby the flange 15 of the immersion nozzle 6 is fixed to the fixing member 31. Therefore, the slide guide 14 is pressed against and fixed to the opposite slide guide 14.

  From the above, as shown in an enlarged view in FIG. 6, the slide guide 14 has a shape in which the contact surface 14 c with the flange 15 at the center portion protrudes slightly toward the moving connection space D side, and further on the upstream side of the slide guide 14. By providing a taper on the downstream side, the movement of the immersion nozzle 6 is configured to be smooth.

  Further, as shown in FIGS. 5 and 6, the movement guide hole 36 of the fixing member 31 is provided in the piece 11 a of the base 11, and the movement guide 35, which is a protrusion into which the movement guide hole 36 is fitted, is provided in the fixing member 31. It is preferable that the fixing member 31 is prevented from being moved in the downstream direction by being pulled by the movement of the immersion nozzle 6 when replacing the immersion nozzle.

  In the above description, the fixing member 31 is provided on one piece 11a of the base 11, but may be provided on the side of both pieces 11a and 11b toward the moving connection space D. In this case, naturally, the spring piece 33 a is also provided on the other piece 11 b side, the coil spring 33 is fitted into the spring hole 33 a, and the fixing member 31 is fixed to the coil spring 33. As a matter of course, a fixing member 31 is provided instead of the slide guide 14.

  As described above, the apparatus for continuous slab casting according to the present invention provides a base that is a platform for a rotating mechanism when the direction of the discharge hole of the immersion nozzle is changed during casting (operation). Since it can be fixed, the direction can be changed to an accurate angle, and the molten metal can be appropriately stirred in accordance with the condition of the mold, so that the quality of the slab can be improved.

DESCRIPTION OF SYMBOLS 1 Tundish 2 Upper nozzle 3 Stopper 4 Lower nozzle 5 Housing 6 Immersion nozzle 6e Immersion nozzle 6n after use 6n Unused immersion nozzle 10 Stopper type flow control mechanism 11 Base 12 Coil spring 13 Clamper 14 Slide guide 15 Immersion nozzle flange 16 Clamper pin 17 Guide rail 20 Nozzle replacement holding mechanism 21 Support guide 22 Support guide roller 23 Drive unit (hydraulic cylinder)
25 Protruding portion 27 Lever 29 Nozzle replacement hydraulic cylinder 30 Fixing mechanism 31 Fixing member 32 Bolt (foot of fixing member)
33 Coil spring 35 Movement guide 36 Movement guide hole 37 Projection

Claims (6)

A slab continuous casting apparatus that supplies molten metal to a mold from a tundish through a stopper-type flow rate adjusting mechanism and an immersion nozzle,
A base disposed between the stopper-type flow rate adjusting mechanism and the immersion nozzle;
When replacing the nozzle, the immersion nozzle is moved through a moving connection space provided in the base, and during operation, the immersion nozzle disposed in the molten metal flow path is lifted upward to maintain the connectivity of the immersion nozzle. A nozzle replacement holding mechanism,
A rotation mechanism for rotating the base;
The immersion nozzle arranged in the flow path by the nozzle replacement holding mechanism is urged in a direction perpendicular to the immersion nozzle movement direction at the time of nozzle replacement in the moving connection space, and is pressed and fixed to the inner wall of the movement connection space. A fixing mechanism;
Slab continuous casting equipment with   The fixing mechanism includes an elastic material or an actuator disposed on one of two pieces of the base that are arranged opposite to each other to constitute the moving connection space, and the moving connection is performed by the elastic material or the actuator. The apparatus for continuous slab casting according to claim 1, wherein the position of the immersion nozzle is fixed by urging one side surface of the flange of the immersion nozzle held in the space and pressing the other side surface against the other piece.   The fixing mechanism includes an elastic material or an actuator disposed on both pieces of the two pieces of the base that are arranged opposite to each other and constitutes the moving connection space, and is held in the movement connection space by the elastic material or the actuator. The apparatus for continuous slab casting according to claim 1, wherein the position of the immersion nozzle is fixed by urging the flange side surface of the immersion nozzle from both sides.   The slab continuation according to claim 2 or 3, wherein a fixing member in a direction parallel to a moving direction of the immersion nozzle is attached to a tip of the elastic material or the actuator, and the fixing member presses one side surface of the flange of the immersion nozzle. Casting equipment.   The slab continuous casting apparatus according to any one of claims 1 to 4, wherein an urging force of the fixing mechanism is 300 to 5000 N (30 to 500 kgf).   Protrusions that protrude in a direction perpendicular to the moving direction are provided at both ends of the moving direction of the immersion nozzle on the contact surface of the fixing member with the immersion nozzle, and the protrusions are tapered upstream and downstream in the moving direction. The slab continuous casting apparatus according to claim 4, wherein:

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