KR20040062867A - Device for conveying and cooling a metal strand - Google Patents

Abstract

PURPOSE: To provide a device for conveying and cooling metal strand to ensure that coolant is uniformly flown into cooling chamber from the vicinity of the surface having high temperature of the metal strand for a long period of time. CONSTITUTION: In a device for conveying and cooling metal strand comprising strand guiding rolls(12) supported to the inside of a roll stand(8) to which the metal strand is supported, a strand guide equipped with a cooling chamber(20) which is designed in such a way that the cooling chamber is opened toward the metal strand and sealed toward a supporting structure(24) of the roll stand, and into which coolant is flown through one or more of spray nozzles, and one or more groups of continuous strand guiding rolls(12) that are at least partially positioned inside the cooling chamber as a device for conveying and cooling the metal strand(6), preferably steel strand preferably inside the strand guide of a continuous casting facility, the device for conveying and cooling the metal strand is characterized in that one or more of the spray nozzles are positioned at the outer side of the cooling chamber, and passage openings(22) for the coolant allotted to the spray nozzles and discharged from the spray nozzles are arranged on the wall(21) of the cooling chamber.

Description

Device for conveying and cooling metal strands {DEVICE FOR CONVEYING AND COOLING A METAL STRAND}

The present invention comprises a strand guiding roll supported in a roll stand, which is open to the metal strand and designed to be sealed towards the support structure of the roll stand, with a cooling chamber into which coolant is introduced through one or more spray nozzles. A device for conveying and cooling strands, preferably steel strands, preferably steel strands, in strand guides, preferably in strand guides of continuous casting plants, wherein at least one group of continuous strand guiding rolls is at least partially inside the cooling chamber. Is located.

In a process for producing combustively cast metal strands in a continuous casting plant, hot metal strands, which are primarily only partially solidified when the hot metal strands leave the permanent mold, are fully solidified metal strands with optimum microstructure. It is necessary to undergo strong cooling in the strand guide along the permanent mold so that is obtained within the shortest possible distance. Large amounts of heat have to be dissipated, for example (relatively), especially for hot molten metals and alloys thereof, such as steel. The cast metal strand is guided by a strand guiding roll rotatably supported at the roll stand. At the same time, the thermal load on the strand guiding roll adversely affects its service life, and since the deformation of the strand guide adversely affects the quality of the cast metal strand, the supporting structure of the strand guiding roll and the roll stand has to be Remember to get the smallest load possible.

Arranging the cooling chambers in the strand guiding roll area and introducing the cooling medium in the sprayed form into these cooling chambers by means of a two-fluid nozzle is already known from US 3,946,797 A, RU 2 033 304 C1 and DE-A 27 57 694. Known. The substantially uniformly distributed cooling medium absorbs the radiant energy emitted from the cast metal strands to allow uniform cooling of the strand surface and additionally roll cooling. However, this solution has the disadvantage that the spray nozzles arranged in the cooling chamber are in turn exposed to high thermal loads from the radiant heat and contaminants on the scale peeled off from the surface of the strands. This may cause the spray nozzle to break or at least cause an adversely affected spray pattern, resulting in non-uniform strand cooling due to changes in the nozzle outlet opening.

It is therefore an object of the present invention to avoid the disadvantages of the prior art described above and to propose an apparatus for transporting and cooling metal strands in which a uniform inflow of coolant into the cooling chamber near the hot surface of the metal strands is ensured for a long time. Another object of the present invention is to allow the spray nozzles to be arranged in easily passable positions for maintenance and assembly work.

1 is a longitudinal sectional view of a continuous casting installation comprising a strand guide according to the invention schematically shown;

2 is a longitudinal sectional view of the strand segment in the inner curve with the cooling chamber according to the invention;

3 is a cross-sectional view of a cooling chamber according to the invention as viewed from the spray plane of the spray nozzle;

4 is a cross-sectional view of a cooling chamber according to the present invention in a spray plane of a spray nozzle according to another embodiment of the present invention.

※ Explanation of symbols about main part of drawing ※

6: metal strand 8: roll stand

12: strand guiding roll 18b: inner curve segment

20: cooling chamber 21: wall

22 passage opening 24 support structure

25 support wall 26 welded joint

27: panel 28: edge

30 gap 31 coolant jet

32: two-fluid shaft nozzle 33: attachment piece

34: supply line 35: supply line

36: elastic bridging element

This object is achieved by the fact that one or more spray nozzles are located outside the cooling chamber and a passage opening for the coolant assigned to the spray nozzle and exiting the spray nozzle is arranged in the cooling chamber wall.

On one side of the hot metal strand, two or more strand guiding rolls arranged in succession in the strand transport direction are strand guiding assigned to a common cooling chamber open towards the cooled strand surface to absorb radiant heat emitted from the strand surface. Form a roll group. The cooling chamber includes at least a space between two adjacent strand guiding rolls. The passage openings in the cooling chamber wall are arranged in such a way as to ensure an optimal uniform distribution of coolant introduced as coolant jets predominantly sprayed into the cooling chamber, and thereby a substantially uniform decrease in strand surface temperature.

In this case the passage opening in the cooling chamber wall has a cross section that matches the spray pattern of the spray nozzle. If the spray nozzle is for example a fan-jet nozzle, the passage opening forms a slot whose longitudinal extent is determined by the hole angle of the spray nozzle and the distance from the cooling chamber.

The cooling chamber wall, in particular the rear wall, is formed by a panel fixed to the support wall to shield the support structure of the roll stand or in particular a bar provided on the roll stand for this purpose. This fixation is achieved by screw connection or preferably by welding to this support wall, where the weld seam is impeded to overcome the expansion of the panel. This is also achieved by panels that are wound or bent at their edges.

A useful embodiment of the solution according to the invention consists of a roll stand which is arranged next to each other along the strand guides and which comprises a plurality of strand guiding rolls and in particular is formed by a plurality of strand guiding segments that can be removed individually. The cooling chamber walls of the adjacent segments are connected by bridging elements. This results in a substantially continuous and sealed cooling chamber. It is preferred that the strand guiding segment be assigned to the cooling chamber, as a result of which it is simple to change the segment containing the cooling chamber. Optionally, it is also possible for one segment to be assigned to multiple cooling chambers. The arrangement of the resilient bridging elements between the cooling chambers of adjacent segments allows configurable cooling conditions to be formed without gaps along the entire strand guide. The bridging element may be formed by an elastic or mechanically movable component.

To ensure that the cooling chamber is also structurally sealed on the narrow side of the strand guide, the walls of the cooling chamber are in strand contact with the support structure of the roll stand or the end side of the strand guiding roll, in particular hot metal strands. It is fixed to another boundary wall for side limiting purposes at a distance from the end side wall of the supporting side surface of the roll. This can in particular ensure that the outer bearing of the strand guiding roll provided with a plurality of supports lies outside the cooling chamber in the temperature protection space.

In the case of continuous slab casting equipment, vertical and curve casting equipment, in the region of the strand guide after the strand has been withdrawn from the permanent mold, the roll stands are arranged opposite each other along the strand guide on both sides of the strand, and a plurality of strand guiding It includes a roll and includes a plurality of strand guiding segments, generally referred to as outer curve and inner curve segments in the case of curve fittings. In this segmented arrangement the wall elements of the cooling chambers of the opposing segments are connected by bridging elements so that the cooling chamber arrangement spans. These bridging elements may be formed by resilient or mechanically movable parts, which in turn form a substantially continuous and sealed cooling chamber.

The sealed connection between adjacent segments is also formed by a bridging element comprising a plurality of parts, one group of parts is fixed to the cooling chamber of one segment and another group of parts is fixed to the cooling chamber of the adjacent segment, Adjacent parts simply overlap each other or endure against each other.

Overall, the bridging element allows for the encapsulation of hot metal strands along the strand guides by the coupling between the individual cooling chambers.

The strand guiding roll may be designed without a drive as a pure support roll, or may have a rotary drive as a support and transfer roll.

The strand deformation rolls are in individual pairs or individually, the initial process being immediately after a permanent mold or the termination process over the strand guide process in the transition region of the run-out table, or primarily the process of a horizontal run-out table. It may be arranged in a group of pairs supported on the deformation stand. These strand deformation rolls cause the cast metal strand to undergo a deformation process (soft reduction) in areas where the core is still liquid or after the strand has completely solidified. Preferred configurations of the continuous casting apparatus with the cooling chamber according to the present invention include strand guiding rolls and strand deformation rolls arranged in a desired process in the strand guide, and include one or more groups of strand guiding rolls and / or The strand deformation roll is located at least partially in the cooling chamber.

Therefore, in the field of application of the present invention, the strand guide extends from the outlet side of the permanent mold in the continuous casting plant to the run-out area of the plant, and at least controlled cooling of the metal strand supported by the strand guiding roll As intended, it comprises a predetermined rolling stand arranged in the horizontal run-out area of the continuous casting plant for the direct use of the cast metal strand, preferably separated into strand sections.

Further advantages and features of the present invention will become apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

1 schematically illustrates a longitudinal cross-sectional view of a conventional continuous casting plant for producing a steel strip that can be wound by a continuous manufacturing method including cooling the strand in the strand guide. In the flow direction of the material, the continuous casting plant 1 comprises a tundish 2 from which the liquid steel 3 is cooled through the impregnated casting nozzle 4 into the cooled continuous casting permanent mold 5. Where the liquid steel solidifies to form a metal strand 6 having a core that is still liquid and leaves the permanent mold 5 with a cross section corresponding to the exit cross section of the mold. In the continuous strand guide 7, the metal strands are supported, conveyed and cooled. The metal strands 6 switch from a substantially vertical direction to a substantially horizontal direction in a roll stand 8 that extends on both sides of the wide sidewalls of the cast metal strand and then undergo another treatment for certain desired properties. Take, for example, a reduced thickness in a single- or multi-stand rolling mill 9, then cooled to a coiling temperature in the cooling section 10 and coiled in a winding station 11. . In addition, a furnace installation for the heat treatment of the metal strip may be integrated into the installation.

The strand guide 7 consists of individual parts that can be replaced individually and allows the cast strand to be deformed to form a metal strip that can be coiled. The strand guide 7 is designed to withstand the cast metal strand 6 or to be moved onto the cast metal strand, to form a roll stand 8 and in this way to advance the conveying path for the metal strand 6. It substantially comprises a strand guiding roll 12 to determine. The non-driven strand guiding roll 13 functions exclusively to guide and support the strand in its path through the installation, and the drive strand guiding roll 14 additionally functions for the transfer and controls the transfer speed of the metal strand. do. In addition, the strand deformation roll 15 is integrated into the strand guide, which strand deformation roll 15 influences the conveying direction of the metal strand, for example in the strand bending stand or the strand straightening stand 16, and the core is still The strand deformation stand 17 or the rolling mill 9 for reducing the thickness of the metal strand after the metal strand is completely solidified is liquid and is used to reduce the thickness of the metal strand. A plurality of pairs of strand guiding rolls 12 arranged in succession in the strand conveying direction are combined to form the strand guiding segment 18. According to this segmented arrangement, each of the outer curve segments 18a and each of the inner curve segments 18b are assigned to the cooling chamber 20, and in each case a plurality of rows arranged next to each other in the strand conveying direction. Strand guiding roll 12 and / or strand deforming roll 15. Each cooling chamber 20 is open to the strand surface and limited to the support structure of the roll stand by the roll stand (not shown) and the wall 21. There is a passage opening 22 for coolant in the wall 21, which coolant is discharged from the spray nozzle 23 arranged at a predetermined distance behind the passage opening. The coolant enters the cooling chamber 20 in a finely atomized form and absorbs and dissipates the radiant heat mainly released from the strand surface. The cooling chamber has in particular an outlet opening (not shown) for the coolant collected in the outer curve segment.

FIG. 2 shows the inner curve segment 18b with seven strand guiding rolls 12 which bear against the metal strands 6 and are rotatably mounted to the support structure 24 of the roll stand 8. The support structure 24 comprises a support wall 25 which lies against the strand guiding roll 12 and withstands the strand guiding roll against the support wall (see FIG. 3) and cools on the wall. The wall 21 of the chamber 20 is preferably anchored by screw connection or weld joint 26. The wall 21 is formed by a panel 27 that is bent or rolled at the edge 28 to absorb thermal stress.

The strand guiding rolls 12 are arranged at a short distance from each other, and the coolant jets 31 flowing into the cooling chamber 20 through the passage openings 22 in the wall 21 are separated by a gap (between the adjacent strand guiding rolls). 30) Head inside. As shown in FIG. 3, two spray nozzles 23 are arranged at a predetermined distance behind the passage opening 22 in the gap plane between two adjacent strand guiding rolls 12, and these two spray nozzles 23 are The coolant, which is preferably designed as a fan-jet nozzle and which is in the form of a spray fan, is discharged as a fine spray mist or finely distributed coolant jet 31. The hole angle α of the spray pan and the distance a between the spray nozzle 23 and the wall of the cooling chamber 20 determine the cross section of the passage opening (see FIGS. 3 and 4).

The spray nozzle shown in FIG. 2 is a two-fluid shaft nozzle 32 connected by parallel feed lines 34, 35 for coolant (mainly water) and spray medium (mainly air) by means of an attachment piece 33. Is designed. Two-fluid shaft nozzles of this type are described in detail in DE 102 00 662 A1.

The cooling chambers 20 adjacent to each other in the strand conveying direction can be joined to each other in a sealed manner by the insertion of the elastic bridging element 36 such that the metal strand surface is encapsulated continuously at least in the section (see FIG. 2). The bridging element 36 may be directly adjacent the panel 27 of the cooling chamber 20, or may be fixed to an adjacent support wall 25, such as the panel itself.

In the same way, the narrow sidewall of the metal strand is assigned to an apron or elastic bridging element 37 which laterally restricts the cooling chamber 20 at a distance from the end side of the strand guiding roll 12 (FIG. 3). Reference). Such bridging elements 37 may start from the inner curve segment 18b and the opposing outer curve segment 18a and face each other and overlap each other. The outer bearing 38 of the strand guiding roll 12 is in this case located outside of the cooling chamber 20.

According to the variant design shown in FIG. 4, the wall 21 of the cooling chamber 20 terminates in the frame structure of the inner curve segment 18b. The wall 40 is provided with a substantially continuous, substantially sealed or elastic connection between the frame structure of the inner curve segment 18b and the boundary wall 41, for example a facility casing (operating parallel to the curve strand guide). Form. Similar connections (but not shown) exist between the boundary wall and the frame structure of the outer curve segment.

In the description of the embodiment shown in FIG. 1, the cooling chamber 20 according to the invention is also for the strand deformation rolls 15 which form part of the deformation stands 16, 17 or the rolling mill 9 or the individual rolling stands. Can be used as The combination of the strand guiding roll 12 and the strand deforming roll 15 in the cooling chamber 20 is similarly entirely within the protection scope of the present invention.

The present invention is not limited to this embodiment. Rather, the walls of the cooling chamber with passage openings do not place the strand guiding rolls entirely within the cooling chamber, but rather the walls terminate at a distance from the strand guiding rolls, and therefore the narrow gap between the sides of adjacent strand guiding rolls. It may be arranged in a manner that is located in the area.

Moreover, it is the invention that the cooling chambers adjacent to each other in the strand conveying direction are not connected to each other by the bridging elements, but rather that these bridging elements designed with aprons end at the ends of each cooling chamber towards the strand surface and immediately before the metal strand surface. It is included in the protection scope.

The cooling chamber comprises two or more adjacent strand guiding rolls, and in the smallest situation, the cooling chamber has a mutually opposite side surface section of the strand guiding roll and a passage opening required for the coolant jet and, where appropriate, a side cover. It can be formed by the wall. Complete encapsulation of two adjacent strand guiding rolls with corresponding bridging elements or aprons also forms a cooling chamber herein.

Thus, the present invention can avoid the disadvantages of the prior art described above and can provide an apparatus for transporting and cooling metal strands in which a uniform inflow of coolant into the cooling chamber near the hot surface of the metal strands is ensured for a long time. In addition, spray nozzles may be arranged in easily passable positions for maintenance and assembly operations.

Claims (8)

A strand guiding roll 12 supporting the metal strands and supported within the roll stand 8, designed to open toward the metal strands and to be sealed towards the support structure 24 of the roll stand, and the coolant having one or more spray nozzles ( At least one group of strand guides (7) with cooling chambers (20) introduced through 23, preferably for conveying and cooling metal strands (6), preferably steel strands, within the strand guides of continuous casting plants. In the continuous strand guiding roll 12 of the metal strand conveying and cooling apparatus, at least partially located inside the cooling chamber 20, The one or more spray nozzles 23 are located outside the cooling chamber 20, and passage openings 22 for coolant assigned to the spray nozzles and discharged from the spray nozzles are arranged in the cooling chamber wall 21. Characterized in that Device for conveying and cooling metal strands. The method of claim 1, Characterized in that the passage opening (22) has a cross section coinciding with the spray pattern of the spray nozzle (23), Device for conveying and cooling metal strands. The method according to claim 1 or 2, The wall 21 of the cooling chamber 20 is attached to a panel 27 fixed to the support wall 25 of the roll stand by welding to shield the support structure 24 of the roll stand 8. Characterized in that, Device for conveying and cooling metal strands. The method of claim 3, wherein The panel 27 is characterized in that it is bent or wound at its edge 28, Device for conveying and cooling metal strands. The method according to any one of claims 1 to 4, The roll stand 8 is formed by a plurality of strand guiding segments 18 arranged adjacently along the strand guide 7, the strand guiding segments 18 each having a plurality of strand guiding rolls. (12), characterized in that the walls 21 of the cooling chamber 20 of the strand guiding segment 18 adjacent to each other are connected by a bridging element 36, Device for conveying and cooling metal strands. The method according to any one of claims 1 to 5, The walls 21, 40 of the cooling chamber 20 may support the support structure 24 of the roll stand 8 at a predetermined distance from the end side of the strand guiding roll 12 for the purpose of limiting the side of the cooling chamber. Or fixed to another boundary wall 41, Device for conveying and cooling metal strands. The method of claim 6, The roll stand 8 comprises a plurality of strand guiding segments 18a, 18b arranged opposite to each other along the strand guide 7 and comprising a plurality of strand guiding rolls 12. The wall 21 of the cooling chamber 20 of the segment 18 is characterized in that it is connected in a sealed manner by the bridging element 37, Device for conveying and cooling metal strands. The method according to any one of claims 1 to 7, The strand guiding roll 12 and the strand deforming roll 15 are arranged in the predetermined order in the strand guide 7, and the one or more groups of strand guiding roll 12 and / or the strand deforming roll 15 are arranged in a predetermined order. Characterized in that located at least partially within the cooling chamber 20, Device for conveying and cooling metal strands.