JP6248701B2 - Support roll - Google Patents

Description

  The present invention relates to a support roll that supports and conveys a metal material while being subjected to a heat load from the metal material.

  In the continuous casting process, the slab drawn from the lower end of the mold is cooled while being supported and conveyed by a plurality of pairs of support rolls. The slab is one in which the outer peripheral surface of molten metal (for example, molten steel) poured into a mold is cooled and solidified, and a great heat load is applied to the contact surface of the support roll with the slab. When a thermal load is applied, a thermal stress due to thermal expansion is generated on the surface of the support roll, and there is a possibility that a thermal crack occurs. Since it is necessary to replace the support roll in which the thermal crack has occurred, if the service life of the support roll is short, the support roll is replaced in a short period of time, which may increase the cost of equipment maintenance.

  Therefore, a technique for extending the service life of the support roll by relaxing the thermal stress on the surface of the support roll has been proposed. For example, in Patent Document 1, in a continuous casting roll (CC roll), a large number of slits having a relatively high aspect ratio and a curved cavity at the tip (bottom) are formed on the outer peripheral surface of the roll body. Techniques to do this are disclosed. According to the technique described in Patent Document 1, thermal expansion that occurs on the surface of the support roll due to contact with the slab is absorbed by the slit and thermal stress is relieved, so that the occurrence of thermal cracks can be suppressed. It is possible to extend the service life of the roll.

JP 2004-195517 A

  Here, in the technique described in Patent Document 1, electrolytic processing is used to form a slit in the support roll. In electrolytic processing, while supplying an electrolytic solution between a support roll and a processing electrode, by applying voltages of opposite signs to each other, an area close to the processing electrode on the surface of the support roll can be obtained. Dissolved. And a slit is formed by inserting a process electrode to the radial direction of a support roll according to melt | dissolution of a support roll. In such electrolytic processing, there is a limitation on the minimum value of the slit width that can be formed, and there is a possibility that an optimum slit width for absorbing thermal expansion cannot be realized.

  For example, when the slit width is large, the area of the surface of the support roll where the slit is not formed, that is, the area of the area in contact with the slab becomes relatively small. Will increase. Therefore, the wear rate of the surface of the support roll is increased, and the service life of the support roll may be shortened. Thus, in the technique described in Patent Document 1, the formation of a slit on the surface of the support roll suppresses the generation of thermal cracks, but the surface of the support roll cannot be controlled appropriately. There is a possibility that the wear of the roll is accelerated, and there is a possibility that the service life of the roll cannot be extended.

  Then, this invention is made | formed in view of the said problem, The place made into the objective of this invention is in the process in which a thermal load is applied from the said metal material with respect to the support roll which supports and conveys a metal material, It is an object of the present invention to provide a new and improved support roll capable of extending the service life of the support roll.

In order to solve the above-described problems, according to an aspect of the present invention, a support roll for supporting and transporting a metal material, the shaft member extending in the rotation axis direction of the support roll, and fitted to the shaft member A plurality of roll members arranged in the direction of the rotation axis, and a region having a predetermined length in a radial direction including an outer edge portion of the roll member A thin-walled portion having a thinner axial thickness than other regions is formed, and a slit portion is provided in a region corresponding to the thin-walled portion between the opposing surfaces of the roll member adjacent in the rotation axis direction, and the outer periphery of the roll member A support roll is provided in which the ratio of the depth in the radial direction of the slit portion to the width of the slit portion in the portion is 10 or more .

  Moreover, in the said support roll, even if the shape of the said slit part in the cross section in the radial direction of the said support roll is a wedge shape in which the width | variety of the said slit part becomes small uniformly as it goes inside in the said radial direction Good.

  As described above, according to the present invention, it is possible to further extend the service life of the support roll in a process in which a thermal load is applied from the metal material to the support roll that supports and transports the metal material. .

It is a sectional side view showing the schematic structure of the continuous casting machine to which the support roll concerning one embodiment of the present invention is applied. It is a front view which shows the structure of the support roll which concerns on one Embodiment of this invention. It is sectional drawing in the AA cross section of the support roll shown in FIG. It is the external view and sectional drawing which show the shape of the roll member which comprises the roll part shown in FIG. It is sectional drawing which shows one structural example of the conventional support roll. It is the schematic which shows typically a mode that a slab is supported by the conventional support roll in a continuous casting process. It is sectional drawing which shows the structure of the support roll which concerns on the modification whose shape of a slit part is a wedge shape. It is sectional drawing which shows the structure of the support roll which concerns on the modification whose shape of a slit part is a rectangular shape. It is sectional drawing which shows the structure of the support roll which concerns on the modification whose shape of a slit part is a parabolic type. It is explanatory drawing for demonstrating the shape of the slit part of the support roll which concerns on this embodiment. It is a graph which shows the abrasion amount of the radial direction of the support roll after use in a comparative example, Example 1, and Example 2. FIG.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the following description, as an embodiment of the present invention, a case where the support roll according to the present invention is applied to a continuous casting process will be described as an example. In the continuous casting process, the casting speed is about 0 to 4 (mpm: meter per minute), and the plate speed of the metal material is relatively slow. Larger than the process. The support roll according to the present invention is suitably applied to a process in which a large heat load can be applied to the support roll, such as a continuous casting process. However, the present invention is not limited to such examples, and the support roll according to the present invention is a process in which a metal material is supported and transported by the support roll, and a thermal load is applied to the support roll from the metal material. Any process that can be added can be applied to other processes. Even when the support roll according to the present invention is applied to such other processes, the same effects as those described below can be obtained.

<1. Overall configuration of continuous casting machine>
First, a schematic configuration of a continuous casting machine to which a support roll according to an embodiment of the present invention is applied will be described with reference to FIG. FIG. 1 is a side sectional view showing a schematic configuration of a continuous casting machine to which a support roll according to an embodiment of the present invention is applied. In addition, in the drawings shown below including FIG. 1, for the sake of explanation, the size of some constituent members that are the main part of the present invention may be exaggerated. The relative sizes of the constituent members do not necessarily accurately represent the magnitude relationship between the actual constituent members.

  As shown in FIG. 1, a continuous casting machine 20 is an apparatus for continuously casting a molten metal 2 (for example, molten steel) using a casting mold 1 to produce a slab 3 such as a slab. The continuous casting machine 20 includes a mold 1, a ladle 4, a tundish 5, an immersion nozzle 6, a secondary cooling device 7, and a slab cutting machine 8.

  The ladle 4 is a movable container for conveying the molten metal 2 from the outside to the tundish 5. The ladle 4 is disposed above the tundish 5, and the molten metal 2 in the ladle 4 is supplied to the tundish 5. The tundish 5 is disposed above the mold 1, stores the molten metal 2, and removes inclusions in the molten metal 2. The immersion nozzle 6 extends downward from the lower end of the tundish 5 toward the mold 1, and the tip thereof is immersed in the molten metal 2 in the mold 1. The immersion nozzle 6 continuously supplies the molten metal 2 from which inclusions have been removed in the tundish 5 into the mold 1.

  The mold 1 has a rectangular tube shape corresponding to the width and thickness of the slab 3, and is assembled, for example, such that a pair of short-side mold plates are sandwiched from both sides in the width direction by a pair of long-side mold plates. These mold plates are made of, for example, a water-cooled copper plate. The mold 1 cools the molten metal 2 coming into contact with the mold plate, and manufactures a slab 3 including an unsolidified portion 3b inside the solidified shell 3a of the outer shell. As the solidified shell 3a moves downward in the mold 1, solidification of the inner unsolidified portion 3b proceeds, and the thickness of the outer solidified shell 3a gradually increases. The slab 3 including the solidified shell 3 a and the unsolidified portion 3 b is pulled out from the lower end of the mold 1.

  The secondary cooling device 7 is provided in the secondary cooling zone 9 below the mold 1 and cools the slab 3 drawn out from the lower end of the mold 1 while supporting and transporting it. The secondary cooling device 7 includes a plurality of pairs of support rolls (for example, a support roll 11, a pinch roll 12 and a segment roll 13) disposed on both sides in the thickness direction of the slab 3, and cooling water for the slab 3. A plurality of spray nozzles (not shown). The support roll according to the present invention can be applied as the support roll.

  The support rolls provided in the secondary cooling device 7 are arranged in pairs on both sides in the thickness direction of the slab 3 and function as a support and transport means for transporting the slab 3 while supporting it. By supporting the slab 3 from both sides in the thickness direction with the support roll, breakout and bulging of the slab 3 during solidification in the secondary cooling zone 9 can be prevented.

  The said support roll contains the support roll 11, the pinch roll 12, and the segment roll 13 which are shown in FIG. The support roll 11, the pinch roll 12 and the segment roll 13 form a transport path (pass line) for the cast piece 3 in the secondary cooling zone 9. As shown in FIG. 1, this pass line is vertical immediately below the mold 1, then curves in a curved shape, and finally becomes horizontal. In the secondary cooling zone 9, a portion where the pass line is vertical is called a vertical portion 9A, a curved portion is called a curved portion 9B, and a horizontal portion is called a horizontal portion 9C. The continuous casting machine 20 having such a pass line is referred to as a vertical bending type continuous casting machine 20. The support roll according to the present invention is not limited to the vertical bending type continuous casting machine 20 as shown in FIG. 1, and can be applied to other various continuous casting machines such as a curved type or a vertical type.

  Here, the support roll 11, the pinch roll 12, and the segment roll 13 will be described. The support roll 11 is a non-driven roll provided in the vertical portion 9 </ b> A immediately below the mold 1, and supports the slab 3 immediately after being pulled out of the mold 1. The slab 3 immediately after being drawn out from the mold 1 has a thin solidified shell 3a, and therefore needs to be supported at a relatively short interval (roll pitch) in order to prevent breakout and bulging. Therefore, as the support roll 11, it is desirable to use a roll with a small diameter that can shorten the roll pitch. In the example shown in FIG. 1, three pairs of support rolls 11 made of small-diameter rolls are provided at a relatively narrow roll pitch on both sides of the slab 3 in the vertical portion 9A.

  The pinch roll 12 is a drive roll that is rotated by a driving means such as a motor, and has a function of pulling the slab 3 out of the mold 1. The pinch rolls 12 are respectively arranged at appropriate positions in the vertical portion 9A, the curved portion 9B, and the horizontal portion 9C. The slab 3 is pulled out of the mold 1 by the force transmitted from the pinch roll 12 and is conveyed along the pass line. In addition, arrangement | positioning of the pinch roll 12 is not limited to the example shown in FIG. 1, The arrangement position may be set arbitrarily.

  The segment roll 13 (also referred to as a guide roll) is a non-driving roll provided in the bending portion 9B and the horizontal portion 9C, and supports and guides the slab 3 along the pass line. The segment roll 13 depends on the position on the pass line, and on the F surface (Fixed surface, lower left surface in FIG. 1) and L surface (Loose surface, upper right surface in FIG. 1) of the slab 3, They may be arranged with different roll diameters and roll pitches.

  The slab cutting machine 8 is disposed at the end of the horizontal portion 9C of the pass line, and cuts the slab 3 conveyed along the pass line to a predetermined length. The cut thick plate-shaped slab 14 is transported to the next process equipment by the table roll 15.

  The overall configuration of the continuous casting machine 20 to which the support roll according to the present invention is applied has been described above with reference to FIG. In addition, the kind and size of the slab 3 manufactured by the continuous casting machine 20 are not specifically limited. For example, the slab 3 may be a slab having a thickness of about 250 to 300 (mm), a bloom or billet exceeding 500 (mm), or a thin slab having a thickness of about 100 (mm), It may be a continuous strip cast strip of 50 mm or less. Moreover, the raw material of the slab 3 should just be a metal which can be continuously cast, for example, various metals, such as aluminum, aluminum alloy, titanium other than steel and special steel, may be sufficient.

<2. Configuration of Support Roll>
[2-1. Configuration of Support Roll According to this Embodiment]
Next, with reference to FIG. 2, the structure of the support roll which concerns on one Embodiment of this invention is demonstrated. FIG. 2 is a front view showing a configuration of a support roll according to an embodiment of the present invention. Referring to FIG. 2, the support roll 10 according to the present embodiment includes a shaft member 110 and a roll unit 120. In the following description, the rotation axis direction of the support roll 10 is defined as the z-axis direction. Two directions orthogonal to each other in a plane perpendicular to the z-axis direction are defined as an x-axis direction and a y-axis direction, respectively.

  Here, the support roll 10 is a general term for the support roll 11, the pinch roll 12, the segment roll 13 and the like shown in FIG. Thus, the support roll 10 according to the present embodiment may be applied to any roll used in the continuous casting machine 20. The support rolls 10 are arranged in pairs on both sides in the thickness direction of the slab 3 and have a function of supporting the slab 3 from both sides. Further, the support roll 10 rotates with the movement of the slab 3 as a rotation axis direction in the z-axis direction (the direction perpendicular to the paper surface in FIG. 1), and guides and conveys the slab 3 along the predetermined pass line described above. It also has a function to By providing a plurality of pairs of such support rolls 10 on both sides of the pass line, it is possible to prevent bulging deformation in which the center portion in the width direction of the slab 3 swells and breakout due to breakage of the solidified shell 3a.

  The shaft member 110 is a rod-shaped member that extends in the rotation axis direction (that is, the z-axis direction) of the support roll 10. The roll portion 120 has a substantially cylindrical shape, and is fitted to the outer peripheral portion of the shaft member 110 such that the axial direction of the cylindrical shape matches the extending direction of the shaft member 110. When the slab 3 is supported and conveyed, the outer peripheral surface of the roll unit 120 comes into contact with the slab 3. Both ends of the shaft member 110 are supported by bearing portions (not shown in FIG. 1) provided in the continuous casting machine 20, and the shaft member 110 and the roll portion 120 are integrated with the z-axis direction as the rotation axis direction. Is configured to rotate. Thus, it can be said that the support roll 10 according to the present embodiment is a sleeve roll in which the roll portion 120 is fitted to the outer peripheral portion of the shaft member 110.

  The diameter of the support roll 10 is, for example, about 100 (mm) to 450 (mm). For example, when the diameter of the support roll 10 is about 400 (mm), the outer diameter of the shaft member 110 may be about 350 (mm). Further, for example, the length of the support roll 10 in the rotation axis direction is about 300 (mm) to 3000 (mm). The specific shape of the support roll 10 is appropriately selected according to the type and size of the slab 3 manufactured in the continuous casting process.

  Here, with reference to FIG. 3, the structure of the shaft member 110 and the roll part 120 is demonstrated in detail. 3 is a cross-sectional view taken along the line AA of the support roll 10 shown in FIG. However, in FIG. 3, for the sake of simplicity, the illustration of the vicinity of both ends of the support roll 10 in the AA cross section is omitted.

  Referring to FIG. 3, a space 111 penetrating in the z-axis direction is provided inside the shaft member 110. For example, cooling water for cooling the support roll 10 flows in the space 111. Since the heat load from the slab 3 is applied to the support roll 10 that supports and transports the slab 3, the support roll 10 needs to be continuously cooled throughout the process. When the cooling water flows into the space 111 inside the shaft member 110, the support roll 10 can be cooled from the inside. As described above with reference to FIG. 1, the continuous casting machine 20 is provided with a plurality of spray nozzles that inject cooling water onto the slab 3. The cooling water sprayed from the spray nozzle is intended to cool the slab 3, but the support roll 10 can also be cooled by the water sprayed and flowed down to the slab 3. As described above, the support roll 10 is configured so that when the slab 3 is supported and transported, the cooling roll that flows into the space 111 inside the shaft member 110 and the cooling water that is sprayed from the spray nozzle cause the inside and outside of the support roll 10 to move. Can be cooled.

  The roll unit 120 includes a plurality of roll members 121. The roll member 121 has a substantially annular shape and is fitted to the outer periphery of the shaft member 110. The plurality of roll members 121 are arranged in the z-axis direction with the openings 122 facing each other, and the shaft member 110 is inserted and fitted into the plurality of openings 122 that are continuous in the z-axis direction. Thus, the support roll 10 is configured by fitting a plurality of roll members 121 having an annular shape to the shaft member 110 in a sleeve shape. A plurality of roll members 121 arranged in the z-axis direction and fitted to the outer peripheral portion of the shaft member 110 can form the roll portion 120 having a cylindrical shape shown in FIG. The roll member 121 can be formed of, for example, martensitic stainless steel, austenitic stainless steel, cemented carbide, or the like.

  Further, the roll members 121 are arranged in the z-axis direction so as to have a predetermined distance from each other at least at the outer peripheral portion, and are fitted to the outer peripheral portion of the shaft member 110. When the slab 3 is supported and conveyed, the outer peripheral surface of the roll part 120, that is, the annular outer peripheral part of the roll member 121 abuts on the slab 3. Therefore, when the roll members 121 are arranged so as to have a predetermined distance from each other at least at the outer peripheral part, the distance functions as a slit part on the surface of the roll part 120 in contact with the cast piece 3.

  In a region of the roll member 121 having a predetermined length in the radial direction including at least the outer edge portion, a thin-walled portion whose thickness in the z-axis direction is thinner than other regions is formed. Here, the said other area | region is an area | region where the adjacent roll members 121 contact | abut mutually, for example, when the roll member 121 is fitted to the shaft member 110 and it arranges without a gap, and is an example shown in FIG. Then, it corresponds to a region having a predetermined length in the radial direction from the edge of the opening 122. By providing the roll member 121 with the thin-walled portion, the roll member 121 is arranged in the z-axis direction so as to have a predetermined distance from each other at the outer peripheral portion. Specifically, a slit portion 123 having a predetermined depth in the radial direction is formed in a region corresponding to the thin portion between adjacent roll members 121. The depth (slit depth) of the slit portion 123 is defined by the radial length of the region where the thin portion is formed, and the slit is determined by the difference in thickness in the z-axis direction between the thin portion and the other region. The width (slit width) of the portion 123 in the rotation axis direction is defined. Further, the interval (slit pitch) between the slit portions 123 is defined by the thickness in the z-axis direction of the region other than the thin portion of the roll member 121.

  In addition, in the example shown in FIG. 3, it has not only the area | region corresponding to a thin part among the opposing surfaces of the roll member 121, but the predetermined length to radial direction from the said other area | region, for example, the edge part of the opening part 122. Although the regions are illustrated as being provided with a predetermined interval in the z-axis direction, the present embodiment is not limited to such an example. In the present embodiment, the roll members 121 may be arranged without a gap in the z-axis direction except for the region corresponding to the thin portion.

  Here, the shape of the roll member 121 will be described in more detail with reference to FIG. 4A and 4B are an external view and a cross-sectional view showing the shape of the roll member 121 constituting the roll unit 120 shown in FIG. In FIG. 4, an external view of one roll member 121 viewed from the z-axis direction and a cross-sectional view taken along the line BB shown in the drawing are shown together.

  Referring to FIG. 4, the thin-walled portion 124 is provided in a region having a predetermined length d from at least the outer edge portion of the roll member 121 in the radial direction (x-axis direction in the cross-sectional view shown in FIG. 4). Assuming that the region located on the inner side in the radial direction from the thin portion 124 of the roll member 121 is referred to as another region 127, as described above, the thin portion 124 has a thickness in the z-axis direction that is other than that. It is formed thinner than the region 127. The other region 127 may be a region where the adjacent roll members 121 come into contact with each other when the roll members 121 are fitted to the shaft member 110 and arranged without gaps, for example. In the example illustrated in FIG. 4, the other region 127 corresponds to a region having a predetermined length in the radial direction from the edge of the opening 122.

  Referring to FIG. 4, for example, the thin portion 124 includes a first region 125 and a second region 126. The first region 125 is a region having a predetermined length shorter than the length d in the radial direction from the outer edge portion of the roll member 121. In the example illustrated in FIG. 4, a step portion having a constant depth t in the z-axis direction is formed in the first region 125. The second region 126 is a region that is continuously formed in the radial direction with the first region 125. The second region 126 has a predetermined radius R (for example, R = 3) in the radial cross section. (Mm)) having a circular arc-shaped cross section is formed. As shown in the external view of FIG. 4, the second region 126 is a surface of the roll member 121 that is a surface perpendicular to the z-axis direction and that faces another adjacent roll member 121 (hereinafter simply referred to as “opposing surface”). It may be a region provided in a circumferential shape on the surface of “. The sum of the radial length of the first region 125 and the radial length of the second region 126 is the radial length d of the region where the thin portion 124 is formed. As described above, the thin portion 124 can be realized by forming a stepped portion or a recessed portion in a region having a predetermined length in the radial direction including at least the outer edge portion on the facing surface of the roll member 121.

As shown in FIG. 4, the roll member 121 has a thin portion 124 formed in a partial region thereof, so that the thickness (t ₂ ) in the z-axis direction in the outer peripheral portion is the z-axis direction in the other region 127. It is formed to be thinner than the thickness (t ₁ ). As shown in FIG. 3, in the support roll 10, the roll members 121 are arranged with their opposing surfaces facing each other. Therefore, if the roll members 121 are arranged without gaps in the z-axis direction, they are adjacent to each other. A slit portion 123 having a width of t ₂ −t ₁ = 2t is formed at least on the outer peripheral portion between the matching roll members 121. Thus, in this embodiment, the width of the slit portion 123 formed on the surface of the support roll 10 can be controlled by the difference between the thickness of the thin portion 124 of the roll member 121 and the thickness of the other region 127.

  As described above with reference to FIGS. 2 to 4, in the present embodiment, the plurality of roll members 121 having an annular shape are arranged in the z-axis direction, whereby the roll portion 120 of the support roll 10 is formed. Composed. Moreover, in the roll part 120, the roll member 121 is arranged so that it may have a predetermined space | interval mutually at least in an outer peripheral part. When the roll member 121 is assembled as the roll part 120, the interval can function as the slit part 123 on the surface of the roll part 120. Thus, in this embodiment, by arranging the plurality of roll members 121 so as to have a predetermined interval from each other at least at the outer peripheral portion, the roll member 120 is arranged on the surface of the roll unit 120 according to the interval between the roll member 121 and the roll member 121. A slit portion 123 is formed. Specifically, for example, by providing the thin portion 124 in a region having a predetermined length in the radial direction including at least the outer edge portion of the roll member 121, the outer peripheral portion between the roll members 121 arranged by the thin portion 124. When the roll member 121 is assembled as the roll part 120, the slit part 123 can be formed.

[2-2. Comparison with conventional support rolls]
Here, in order to explain the effect of the support roll 10 according to the present embodiment in more detail, the configuration of the conventional support roll will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a configuration example of a conventional support roll. In addition, in FIG. 5, schematic structure of the roll for continuous casting described in the said patent document 1 is illustrated as one structural example of the conventional support roll. Further, in the cross-sectional view shown in FIG. 5, a slit near the outer peripheral portion of the support roll is formed in a cross-section corresponding to the cross-sectional view shown in FIG. 3 (that is, a cross-section including the rotation axis of the support roll and parallel to the radial direction). Only the region to be displayed is shown.

  Referring to FIG. 5, a plurality of slits 510 along the circumferential direction of the roll are provided on the outer peripheral surface of the roll body of the conventional support roll 50 with a predetermined interval (for example, about 20 (mm)). It is done. The slit 510 is formed with a relatively high aspect ratio (depth / width) (for example, 10 or more). Further, a curved cavity is formed at the bottom of the slit 510.

  The support roll 50 shown in FIG. 5 can be applied as the support roll 11, the pinch roll 12 and the segment roll 13 of the continuous casting machine 20 shown in FIG. In the support roll 50, by providing the slit 510 on the outer peripheral surface of the roll body in this way, thermal expansion caused by contact with the slab 3 is absorbed and thermal stress is relieved, so that thermal cracks are generated. Can be suppressed. Further, the curved hollow portion provided at the bottom of the slit 510 is formed so as to have a radius of curvature of about 2 to 3 (mm), for example, to relieve stress concentration at the bottom of the slit 510. It has a function.

  However, in the conventional support roll 50, the slit 510 is formed by processing the surface of one cylindrical roll member. Therefore, depending on the processing method of the slit 510, the width and interval of the slit 510 are limited, and there is a possibility that an optimal slit shape cannot be realized. For example, in the technique described in Patent Document 1, electrolytic processing is used to form the slit 510 in the support roll 50. In the electrolytic processing, while supplying an electrolytic solution between the support roll 50 and the processing electrode, voltages having opposite signs are applied between the two, thereby approaching the processing electrode on the surface of the support roll 50. The area is dissolved. Then, the slit 510 is formed by inserting the processing electrode in the radial direction of the support roll 50 in accordance with the dissolution of the support roll 50.

  As described above, a curved cavity for relaxing stress concentration is provided at the bottom of the slit 510, and the cavity is formed to have a curvature radius of approximately 2 to 3 (mm). If an attempt is made to form the slit 510 having such a shape by electrolytic processing, a thickness corresponding to the processing electrode inserted to form the slit 510 is required, and thus the minimum value of the slit width that can be formed is limited. Specifically, according to the study by the inventors, when an attempt is made to form a slit 510 having a curved cavity with a curvature radius of about 2 to 3 (mm) at the tip by electrolytic processing, the width of the slit 510 is It became approximately 4 to 6 (mm), and it was difficult to make the slit width smaller than that.

  Here, in the continuous casting process, for example, in order to suppress bulging deformation of the slab 3, a predetermined rolling force is applied to the support roll 50 in a direction in which the slab 3 is supported. With reference to FIG. 6, the various force which acts between the conventional support roll 50 and the slab 3 is demonstrated. FIG. 6 is a schematic view schematically showing how the slab 3 is supported by the conventional support roll 50 in the continuous casting process. FIG. 6 illustrates a cross-sectional view of the slab 3 and the support roll 50 in a cross section perpendicular to the conveyance direction of the slab 3, for example, in the continuous casting machine 20 illustrated in FIG. In FIG. 6, for simplicity, only one (lower side) of the pair of support rolls 50 arranged on both sides in the thickness direction of the slab 3 is illustrated. The support roll 50 is schematically shown as a rectangle, and the slit 510 is not shown.

  As shown in FIG. 6, a predetermined rolling force is applied to the support roll 50 in the direction in which the slab 3 is supported. Further, a force (bulging force) accompanying the bulging deformation of the slab 3 is applied to the support roll 50 from the slab 3. As described above, various forces corresponding to the rolling force and the bulging force act on the contact surface of the support roll 50 with the slab 3 (that is, the outer peripheral surface of the support roll 50 where the slit 510 is formed). Pressure (contact surface pressure) is applied. In FIG. 6, the rolling force is schematically illustrated with a white arrow, and the force corresponding to the contact surface pressure is illustrated with a solid line arrow. If the width of the slit 510 is large, the area of the surface of the support roll 50 where the slit 510 is not formed, that is, the area in contact with the slab 3 is relatively small. To increase. Therefore, the wear rate of the surface of the support roll 50 is increased, and the service life of the support roll 50 may be shortened.

  Here, in particular, since the shell is formed earlier at the end portion of the slab 3 than the center portion in the width direction of the slab 3, the region of the surface of the support roll 50 that supports the end portion of the slab 3. Can be loaded with a greater rolling force and contact surface pressure than other areas. Therefore, in the region of the surface of the support roll 50 that supports the end portion of the slab 3, there is a possibility that the wear of the surface proceeds significantly more than the other regions. Further, an increase in the contact surface pressure in the region that supports the end portion of the slab 3 may cause the slit 510 to be deformed. FIG. 6 illustrates a state in which the area of the surface of the support roll 50 is enlarged with respect to the deformation of the slit 510 that may occur in the area that supports the end of the slab 3. As shown in FIG. 6, in the area | region which supports the edge part of the slab 3, there exists a possibility that the slit 510 may be crushed and deform | transformed by a great contact surface pressure. When the slit 510 is crushed, the original effect of reducing the thermal stress of the slit 510 cannot be obtained, and the shape of the support roll 50 in the radial direction is deformed, so that the support roll 50 needs to be replaced.

  As described above with reference to FIGS. 5 and 6, in the conventional support roll 50, the slit 510 is provided on the outer peripheral surface, so that the thermal stress is relieved and the occurrence of thermal cracks is suppressed. A certain effect can be obtained. However, in the conventional support roll 50, when forming the slit 510, it is difficult to reduce the width of the slit 510 to a predetermined value or less due to the processing method, and the contact surface of the support roll 50 with the slab 3 There was a risk that the pressure would increase. The increase in the contact surface pressure causes an increase in the wear rate of the surface of the support roll 50 and the deformation of the slit 510, thereby shortening the service life of the support roll 50.

  Thus, in order to prolong the service life of the support roll in the continuous casting process, a slit is provided on the surface of the support roll to alleviate thermal stress, and the slab is formed by forming the slit narrower. Therefore, a technique for further reducing the contact surface pressure with 3 has been demanded.

  Here, as described with reference to FIGS. 2 to 4, in the support roll 10 according to the present embodiment, a plurality of roll members 121 having an annular shape are arranged in the z-axis direction, whereby the roll unit 120. Is configured. In addition, the roll members 121 are arranged so as to have a predetermined interval at least in the outer peripheral portion, whereby the slit portion 123 is configured on the surface of the roll portion 120 by the interval. For example, the roll member 121 is provided with a thin portion 124 whose thickness in the z-axis direction is thinner than other regions 127 in a region having a predetermined length in the radial direction including at least the outer edge portion. The other region 127 may be a region where the adjacent roll members 121 come into contact with each other when the roll members 121 are fitted to the shaft member 110 and arranged without gaps, for example. Therefore, the slit portion 123 is formed in a region corresponding to the thin portion 124 between the adjacent roll members 121. The formation of the thin portion 124 with a predetermined shape in a partial region of the annular roll member 121 can be realized with high accuracy by existing machining techniques, and thus is defined by the shape of the thin portion 124. The shape of the slit portion 123 (for example, the slit width and the slit depth) can be controlled with high accuracy. In addition, since the thickness in the z-axis direction in the other region 127 of the roll member 121 can be adjusted with high accuracy by an existing machining technique, the slit pitch of the slit portion 123 defined by the thickness is also highly accurate. Can be controlled.

  Therefore, in the support roll 10 according to the present embodiment, the slit width and slit pitch of the slit portion 123 on the surface of the support roll 10 is such that the wear rate is reduced while absorbing thermal expansion and relaxing thermal stress. It becomes possible to control to an optimum value. In the present embodiment, for example, the thin portion 124 is formed so that the slit width of the slit portion 123 is about 0.1 (mm) to 1 (mm). Further, the thickness of the other region 127 of the roll member 121 is adjusted so that the slit pitch of the slit portion 123 is, for example, about 15 (mm). Further, the depth of the slit portion 123 is controlled to a value at which the influence of the thermal load in the radial direction of the support roll 10 can be sufficiently reduced. In the present embodiment, for example, the thin portion 124 is formed so that the slit depth of the slit portion 123 is about 15 (mm). In addition, about the design method at the time of designing the slit width of the slit part 123, a slit depth, and a slit pitch, following <4. The shape will be described in detail below.

  Thus, in this embodiment, since the slit part 123 is formed by the thin part 124 formed in the roll member 121 when the roll member 121 is assembled as the roll part 120, the conventional support roll 50 described above. It is possible to form the slit portion 123 having a smaller slit width than the slit 510. Therefore, the contact surface pressure from the slab 3 can be reduced as compared with the conventional support roll 50, and the wear rate can be reduced. Thus, in the support roll 10 according to the present embodiment, the width of the slit portion 123 on the surface of the support roll 10 is optimized so that the wear rate is reduced while absorbing thermal expansion and relaxing thermal stress. Since the value can be controlled, the service life of the support roll 10 can be extended.

  In addition, as a processing method of the opening part 122 and the thin part 124 in the roll member 121, the existing various processing methods, such as cutting, forging, casting, and sintering, can be used, for example. A plurality of roll members 121 in which openings 122 and thin portions 124 having a predetermined shape are formed by a predetermined processing method, and shaft members 110 are arranged in openings 122 of a predetermined number of roll members 121 arranged in a row. The support roll 10 is manufactured by inserting. When the support roll 10 is manufactured, the outer peripheral surface of the roll member 120 is polished by collectively polishing the outer peripheral surface of the roll member 121 after fitting a predetermined number of roll members 121 to the shaft member 110. In other words, a step of improving the flatness of the outer peripheral surfaces of the plurality of roll members 121 arranged in one row may be performed.

  The roll member 121 can be formed of, for example, martensitic stainless steel, austenitic stainless steel, cemented carbide, or the like. By using a super hard material as the roll member 121, the wear of the surface of the support roll 10 can be further suppressed. Here, when an integral member is to be formed of cemented carbide, the size of the workable member may be limited from a technical viewpoint. Therefore, as shown in FIG. 5, the conventional support roll 50 constituted by one cylindrical roll member is formed of super hard material, depending on the size of the support roll 50, from the viewpoint of processing technology. It can be difficult. However, in this embodiment, since the roll part 120 of the support roll 10 is comprised by combining the some roll member 121, even if it is a comparatively large-sized support roll 10, the roll member 121 which is the structural member is It can be formed in a relatively small size. Therefore, the roll member 121 can be formed of a cemented carbide material, wear on the surface of the support roll 10 is further suppressed, and the service life of the support roll 10 can be further extended.

  Moreover, in the support roll 10 which concerns on this embodiment, the material of the one part roll member 121 of the some roll members 121 may be changed according to the use conditions at the time of continuous casting, for example. For example, when it can be assumed in advance that a large contact surface pressure is applied to a predetermined roll member 121 among the plurality of roll members 121, the material of the predetermined roll member 121 is more than that of the other roll members 121. It can be changed to a material having a high hardness. For example, as described above with reference to FIG. 6, in the continuous casting machine 20, a large contact surface pressure acts on the region of the support roll 10 that supports the end portion of the slab 3 as compared with other regions. Can do. Accordingly, among the roll members 121 constituting the roll portion 120 of the support roll 10, a cemented carbide material is used for the portion of the roll member 121 corresponding to the region that supports the end portion of the slab 3, and the other regions are supported. Stainless steel may be used for the roll member 121 of the portion to be performed. In this way, by predicting a place where a greater load will be applied on the surface of the support roll 10, by selectively changing the material of the roll member 121 to a material having higher hardness only in the place, the support roll The wear of the surface of 10 can be further suppressed, and the service life of the support roll 10 can be further extended. In addition, since the position of the area | region which supports the edge part of the slab 3 in the surface of the support roll 10 can change according to the size of the slab 3 manufactured in a continuous casting process, among the some roll members 121 The roll member 121 whose material can be changed may be appropriately selected according to the size of the slab 3.

  Moreover, in this embodiment, since the roll part 120 of the support roll 10 is comprised by the several roll member 121, even if it is a case where some roll members 121 are damaged, for example, all the support rolls 10 are replaced | exchanged. There is no need. In order to repair the support roll 10, it is only necessary to replace the damaged roll member 121, and it is possible to reduce the cost required for equipment maintenance. Here, since the conventional support roll 50 is composed of one cylindrical roll member as described above, it is necessary to replace all of the support rolls 50 even if a predetermined region in the rotation axis direction is damaged. there were. In addition, it is difficult to change the material only in a predetermined region in the rotation axis direction of the support roll 50. However, the support roll 10 according to the present embodiment includes the roll unit 120 including a plurality of roll members 121 arranged in the rotation axis direction. Therefore, as described above, it is possible to perform precautions such as partial repair when the support roll 10 is damaged, and predicting a location that is likely to be damaged in advance and changing the material only in the location in the rotation axis direction. Costs required for maintenance can be reduced.

  Further, as described above, the support roll 10 according to the present embodiment has a sleeve shape in which a plurality of roll members 121 are fitted to the shaft member 110. Therefore, for example, as shown in FIG. 3, if a crack from the surface of the roll part 120 to the outer peripheral surface of the shaft member 110 exists between the roll member 121 and the roll member 121 in the z-axis direction from the beginning. Can be considered. Therefore, even when a thermal load is applied to the support roll 10, it is considered that the possibility of thermal cracks occurring in the roll member 121 itself is low. Further, even when a thermal crack that progresses in the radial direction occurs, the progress of the thermal crack is stopped by the outer peripheral surface of the shaft member 110. Damage can be prevented.

  In the example shown in FIGS. 3 and 4, the thin portion 124 has a first region 125 and a second region 126, and a portion corresponding to the bottom of the slit portion 123 corresponds to the second region 126. Yes. By arranging a plurality of roll members 121 having such thin-walled portions 124 in the z-axis direction, the thin-walled portions 124 between adjacent roll members 121 are separated from the outer peripheral portion of the roll member 121 as shown in FIG. A slit 123 having a curved space (hollow part) having a predetermined radius R at the bottom is formed with a substantially constant width at a predetermined length in the radial direction. In the following description, the shape of the slit portion 123 shown in FIG. 3 is also referred to as a teardrop shape. A heat load is applied to the bottom of the slit portion 123 by radiant heat from the slab 3 that has transmitted the gap of the slit portion 123 or heat that has been conducted through the inside of the roll member 121 from the contact surface with the slab 3, Thermal stress can occur. As in the present embodiment, by forming a slit having a teardrop shape as the slit portion 123, a curved space having a predetermined radius R is provided at the bottom of the slit portion 123. It is possible to avoid stress concentration at a specific portion of the bottom, and it is possible to further suppress the occurrence of thermal cracks due to thermal stress. In order to effectively suppress the stress concentration, the curvature R of the bottom portion of the slit portion 123 is designed to be about 3 (mm), for example. Further, in the slit portion 123 having a teardrop shape, the shape of the slit portion 123 is appropriately adjusted by adjusting the shapes of the first region 125 and the second region 126 in the thin-walled portion 124, so that heat radiation can be performed. The influence on the bottom part of the slit part 123 by can be reduced. For example, by reducing the depth of the step in the z-axis direction in the first region 125, that is, the width of the slit portion 123, the amount of heat transferred from the slab 3 to the bottom of the slit portion 123 by heat radiation is reduced. Therefore, it is possible to suppress a thermal load due to thermal radiation on the bottom of the slit portion 123.

  3 and 4, as an example of the slit portion 123 in the support roll 10 according to the present embodiment, the thin portion 124 that forms the slit portion 123 has a step portion having a constant depth t in the z-axis direction. The case where the first region 125 to be formed and the second region 126 in which a concave portion having an arc-shaped cross-section with a predetermined radius R is formed in the radial cross section has been described. Is not limited to such an example. In the present embodiment, the thin portion 124 formed in the roll member 121 is a region that has a predetermined length in the radial direction including at least the outer edge portion of the roll member 121, for example, a region that abuts the adjacent roll member 121. It suffices if the thickness in the z-axis direction is made thinner than some other region 127, and the shape may be any shape. Therefore, the shape of the slit portion 123 formed by the thin portion 124 between the roll members 121 arranged adjacent to each other is not limited to the illustrated example, and may be any shape. Other shapes of the thin portion 124 and the slit portion 123 of the support roll 10 are described in <3. Modification> will be described in detail.

<3. Modification>
As described above, in the conventional support roll 50, the slit 510 is formed by electrolytic processing. In the electrolytic processing, since the slit 510 is formed by dissolving the support roll 50 by electrolysis, the shape thereof is limited to, for example, a shape having a curved cavity at the bottom as shown in FIG. It was difficult to form the slit 510 having the shape. On the other hand, in this embodiment, the slit part 123 is formed by the thin part 124 between the adjacent roll members 121. Therefore, by changing the shape of the thin portion 124, the slit portion 123 having various shapes can be formed.

  With reference to FIGS. 7-9, the modification from which the shape of the slit part 123 differs in the support roll 10 which concerns on this embodiment is demonstrated. In the modification described below, only the shape of the slit portion 123 is different, and other configurations may be the same as those of the support roll 10 described above. Therefore, in the following description of the modified example, differences from the above-described embodiment will be mainly described, and detailed description of overlapping items will be omitted. 7 to 9 are cross-sectional views corresponding to the cross-sectional view shown in FIG. 3 (that is, a cross-section including the rotation axis of the support roll and parallel to the radial direction).

[3-1. Modification in which slit shape is wedge-shaped]
First, with reference to FIG. 7, the modification in which the shape of a slit part is a wedge shape in the support roll which concerns on this embodiment is demonstrated. FIG. 7 is a cross-sectional view illustrating a configuration of a support roll according to a modification in which the slit portion has a wedge shape.

  Referring to FIG. 7, a support roll 10a according to this modification includes a shaft member 110 and a roll part 120a. Since the structure of the shaft member 110 is the same as that of the shaft member 110 of the support roll 10 shown in FIG.2 and FIG.3, detailed description is abbreviate | omitted.

  The roll part 120a is constituted by a plurality of roll members 121a. The roll member 121 a has a substantially annular shape and is fitted to the outer peripheral portion of the shaft member 110. The plurality of roll members 121a are arranged in the z-axis direction with the openings 122a facing each other, and the shaft member 110 is inserted and fitted into the plurality of openings 122a that are continuous in the z-axis direction.

  The roll members 121a are arranged in the z-axis direction so as to have a predetermined distance from each other at least at the outer peripheral portion. In the example shown in FIG. 7, a thin-walled portion whose thickness in the z-axis direction is thinner than other regions is provided in a region having a predetermined length in the radial direction including at least the outer edge portion of the roll member 121a. Here, the said other area | region may be an area | region where adjacent roll members 121a mutually contact | abut, for example, when the roll members 121a are arranged without a gap. A slit portion 123a having a predetermined depth in the radial direction is formed by the thin portion between the adjacent roll members 121a.

  As shown in FIG. 7, in this modified example, the thin portion has the thinnest thickness in the z-axis direction at the outer edge portion, and the thickness in the z-axis direction gradually increases toward the inside in the radial direction. It is formed. Specifically, the thin portion is formed such that the thickness in the z-axis direction increases uniformly toward the inner side in the radial direction. Since the thin portion has such a shape, the cross-sectional shape of the slit portion 123a formed by the thin portion between the adjacent roll members 121a becomes a wedge shape as shown in FIG. When the shape of the slit portion 123a is a wedge shape, the stepped portion on the surface of the roll member 121a can be easily processed as compared to the case where the slit portion 123 shown in FIGS. It can be carried out.

  The following <4. As will be described later with respect to the shape of the slit portion>, the thermal stress generated in the roll member 121a has a larger value in the contact region with the cast piece 3 that is a high-temperature object (that is, the outer peripheral surface of the roll member 121a). The value decreases as the distance from the contact area increases, that is, toward the inside in the radial direction. Therefore, the shape of the slit portion 123a for relieving the thermal stress may also be formed so that the slit width gradually decreases toward the inside in the radial direction of the support roll 10a. Since the slit portion 123a according to this modification has a wedge shape that gradually decreases in slit width toward the inner side in the radial direction of the support roll 10a, the inclination angle of the side wall of the slit portion 123a in the wedge shape ( That is, an appropriate shape according to the radial distribution of the thermal stress in the roll member 121a can be realized by appropriately adjusting the degree of reduction of the slit width.

[3-2. Modified example in which the shape of the slit portion is a rectangular shape]
Next, with reference to FIG. 8, the modification in which the shape of a slit part is a rectangular shape is demonstrated in the support roll which concerns on this embodiment. FIG. 8 is a cross-sectional view illustrating a configuration of a support roll according to a modification example in which the slit portion has a rectangular shape.

  Referring to FIG. 8, a support roll 10b according to this modification includes a shaft member 110 and a roll part 120b. Since the structure of the shaft member 110 is the same as that of the shaft member 110 of the support roll 10 shown in FIGS. 2-4, detailed description is abbreviate | omitted.

  The roll part 120b is configured by a plurality of roll members 121b. The roll member 121b has a substantially annular shape and is fitted to the outer peripheral portion of the shaft member 110. The plurality of roll members 121b are arranged in the z-axis direction with the opening portions 122b facing each other, and the shaft member 110 is inserted and fitted into the plurality of opening portions 122b connected in the z-axis direction.

  The roll members 121b are arranged in the z-axis direction so as to have a predetermined distance from each other at least at the outer peripheral portion. In the example shown in FIG. 8, a thin-walled portion whose thickness in the z-axis direction is thinner than other regions is provided in a region having a predetermined length in the radial direction including at least the outer edge portion of the roll member 121b. Here, the said other area | region may be an area | region where adjacent roll members 121b mutually contact | abut, for example, when the roll members 121b are arranged without a gap. A slit portion 123b having a predetermined depth in the radial direction is formed by the thin portion between the adjacent roll members 121b.

  As shown in FIG. 8, in the present modification, the thin portion is formed as a step portion having a substantially constant depth in the z-axis direction on the facing surface. Since the thin-walled portion has such a shape, the cross-sectional shape of the slit portion 123b formed by the thin-walled portion between the adjacent roll members 121b is substantially constant as shown in FIG. It becomes a rectangular type. When the shape of the slit portion 123b is rectangular, the thin portion of the roll member 121b can be easily processed as compared to the case where the slit portion 123 shown in FIGS. Can do. In the example shown in FIG. 8, the corner portion of the bottom portion of the slit portion 123 b is formed at a substantially right angle. However, this modification is not limited to the illustrated example, and the corner portion is a curved surface having a predetermined radius. It may be appropriately processed into a shape. Since the corner part of the bottom part of the slit part 123b has a curved surface shape, the stress concentration in the corner part is relieved and the generation of thermal cracks can be further suppressed.

[3-3. Modified example in which the shape of the slit part is a parabolic shape]
Next, with reference to FIG. 9, the modification in which the shape of a slit part is a parabolic type is demonstrated in the support roll which concerns on this embodiment. FIG. 9 is a cross-sectional view illustrating a configuration of a support roll according to a modification in which the shape of the slit portion is a parabolic shape.

  Referring to FIG. 9, a support roll 10c according to this modification includes a shaft member 110 and a roll part 120c. Since the structure of the shaft member 110 is the same as that of the shaft member 110 of the support roll 10 shown in FIGS. 2-4, detailed description is abbreviate | omitted.

  The roll part 120c is configured by a plurality of roll members 121c. The roll member 121 c has a substantially annular shape and is fitted to the outer peripheral portion of the shaft member 110. The plurality of roll members 121c are arranged in the z-axis direction with the openings 122c facing each other, and the shaft member 110 is inserted and fitted into the plurality of openings 122c that are continuous in the z-axis direction.

  The roll members 121c are arranged in the z-axis direction so as to have a predetermined distance from each other at least at the outer peripheral portion. In the example shown in FIG. 9, a thin-walled portion whose thickness in the z-axis direction is thinner than other regions is provided in a region having a predetermined length in the radial direction including at least the outer edge portion of the roll member 121c. Here, the said other area | region may be an area | region where adjacent roll members 121c mutually contact | abut, for example, when the roll members 121c are arranged without a gap. A slit portion 123c having a predetermined depth in the radial direction is formed by the thin portion between the adjacent roll members 121c.

  As shown in FIG. 9, in this modification, the thin portion has the thinnest thickness in the z-axis direction at the outer edge portion, and the thickness in the z-axis direction gradually increases toward the inside in the radial direction. It is formed. Specifically, the thin-walled portion is formed such that in the radial cross section, the thickness in the z-axis direction gradually increases in a curve as it goes inward in the radial direction. Since the thin part has such a shape, the cross-sectional shape of the slit part 123c formed by the thin part between the adjacent roll members 121c becomes a parabolic shape as shown in FIG. When the shape of the slit portion 123c is a parabolic shape, it is easier to process the stepped portion on the surface of the roll member 121c than when the slit portion 123 shown in FIGS. It can be carried out.

  In the above, with reference to FIGS. 7-9, the modification from which the shape of a slit part differs in the support roll which concerns on this embodiment was demonstrated. In the above description, the tear-drop shape, wedge shape, rectangular shape, and parabolic shape have been described as the shape of the slit portion according to the present embodiment, but the present embodiment is not limited to such an example. In this embodiment, the slit part which has all shapes can be formed by designing the shape of the thin part formed in the surface of a roll member suitably.

  The shape of the slit part according to the present embodiment may be appropriately designed according to, for example, conditions under which a thermal load is applied. For example, in the continuous casting machine 20 shown in FIG. 1, since the cooling degree of the slab 3 is different between the front stage side and the rear stage side, the thermal load applied from the slab 3 to the support roll is different. Further, in the continuous casting machine 20, spray nozzles for injecting cooling water to the slab 3 are disposed at various locations on the pass line of the slab 3, so that they are disposed in the vicinity of the spray nozzle and cooled from the spray nozzle. It can be said that the support roll that can be cooled by water has a smaller thermal load than the support rolls arranged at other positions. Thus, since the thermal load applied to the support roll differs depending on the arrangement position in the continuous casting machine 20, the shape of the slit portion provided in the support roll considers the difference in the amount of heat load according to the arrangement position. And may be designed as appropriate. Moreover, the material of the roll member which comprises the roll part of a support roll may also be suitably selected in consideration of the difference in heat load amount according to the arrangement position in the continuous casting machine 20.

<4. Shape of slit part>
As described above, in this embodiment, the slit portion is formed on the surface of the support roll to absorb thermal expansion and relieve thermal stress. In addition, the shape of the slit portion, particularly the slit width, is designed so that surface wear and deformation of the slit portion hardly occur in consideration of the contact surface pressure with the slab. As described above, in this embodiment, the width, depth, and interval of the slit portion are designed so as to relieve thermal stress in order to suppress thermal cracking, and also suppress wear on the surface and deformation of the slit portion. Therefore, the contact surface pressure can be designed to be further reduced. Hereinafter, as an example of the slit portion of the support roll according to the present embodiment, the slit portion having a wedge shape shown in FIG. 7 will be described as an example, and a design method for designing the shape of the slit portion will be described. . However, the design method of the shape of the slit portion described below can be similarly applied to slit portions having other shapes as described above.

  With reference to FIG. 10, the design method at the time of designing the shape of the slit part of the support roll which concerns on this embodiment is demonstrated in detail. FIG. 10 is an explanatory diagram for explaining the shape of the slit portion of the support roll according to the present embodiment. 10, a part of the slit portion 123a of the support roll 10a shown in FIG. 7 is enlarged and shown. As shown in FIG. 10, the shape of the slit portion 123a can be determined by the slit width a in the z-axis direction, the slit depth d in the radial direction, and the slit pitch p between the adjacent slit portions 123a.

  First, the slit width a will be described. As shown in FIG. 10, the slit width a is the width of the slit portion 123a in the z-axis direction. In the example shown in FIG. 10, since the shape of the slit portion 123a is wedge-shaped, the slit width a is not constant in the radial direction (x-axis direction). Accordingly, when the origin of the x axis is taken on the outer peripheral surface of the roll member 121a (that is, the contact surface with the slab 3), the slit width a can be expressed as a function of x (a = f (x)). The specific shape of the function f (x) can be determined geometrically based on the shape of the slit portion 123a.

  On the other hand, if the temperature of the roll member 121a is increased by the temperature T due to the heat applied from the slab 3, the thermal expansion l in the z-axis direction of the roll member 121a is expressed as a function of the temperature T (l = g (T)). Can be represented. Here, since the support roll 10a is cooled by the cooling water sprayed from the spray nozzle or the cooling water flowing into the shaft member 110 while receiving heat from the slab 3, the temperature T is kept during the continuous casting process. It can change dynamically. By designing the value of the slit width a so that the slit width a is always smaller than the thermal expansion l during the continuous casting process, the deformation in the z-axis direction of the roll member 121a due to thermal expansion is absorbed by the slit portion 123a. And generation of thermal stress can be suppressed. Therefore, the slit width a is preferably designed so as to satisfy the following formula (1).

  The specific form of the function g (T) can be determined based on physical quantities relating to thermal expansion (for example, thermal expansion coefficient, etc.) corresponding to the material of the roll member 121a and various theoretical formulas in general thermal expansion. . Moreover, the temperature T is calculated | required by calculating the temperature distribution inside the roll member 121a by the numerical analysis using a finite element method (FEM: Finite Element Method), for example.

  Next, the slit depth d will be described. As shown in FIG. 10, the slit depth d is a depth in the radial direction (x-axis direction) of the slit portion 123a. Here, the thermal stress generated in the roll member 121a has a larger value in the contact area with the cast slab 3 that is a high-temperature object (that is, the outer peripheral surface of the roll member 121a), and the value increases as the distance from the contact area increases. Decrease. Therefore, when attention is paid to the change of the thermal stress in the x-axis direction, the thermal stress σ generated in the roll member 121a can be expressed as a function of x (σ = h (x)).

Here, in the region of a predetermined depth x _c in the radial direction of the roll member 121a, and fatigue limit sigma _w or allowable stress sigma _a comparable thermal stress of the roll member 121a occurs. Since the thermal expansion by a gap of the slit portion 123a is the thermal stress is absorbed is alleviated by designing the value of the slit depth d as slit depth d reaches the region of the depth x _c, roll thermal stress generated in the member 121a can be made smaller than the fatigue limit sigma _w or allowable stress sigma _a. Therefore, it is preferable that the slit depth d is designed so as to satisfy the following formula (2). However, an appropriate safety factor may be multiplied to the fatigue limit σ _w or the allowable stress σ _a on the right side of the following formula (2). In addition, the specific value of fatigue limit (sigma) _w or allowable stress (sigma) _a can be determined based on an experimental value, literature value, etc. according to the material of the roll member 121a.

Next, the slit pitch p will be described. As shown in FIG. 10, the slit pitch p is an interval at which the slit portions 123a are formed in the z-axis direction. When the slit pitch p is small, the number of the slit parts 123a is relatively increased, and the contact area with the cast piece 3 on the outer peripheral surface of the roll part 120 is reduced. Therefore, as described above with reference to FIG. 6, the contact surface pressure with the slab 3 on the outer peripheral surface of the roll portion 120 may increase, and the slit portion 123 a may be deformed. Therefore, it is preferable that the value of the slit pitch p is designed in a range in which the slit portion 123a is not deformed. Specifically, if the slit pitch when deformed slit portions 123a can occur and the slit pitch p _b, slit pitch p can be designed so as to satisfy the following equation (3). The specific values of the slit pitch p _b, for example by numerical analysis using FEM, can be determined as the value of the slit pitch, such as the amount of deformation of the slit portion 123a is included in the allowable range.

  In the above, with reference to FIG. 10, the design method of the shape of the slit part in the support roll which concerns on this embodiment was demonstrated. In the present embodiment, for example, the slit width a, the slit depth d, and the slit pitch p of the slit portion 123a are designed so as to satisfy the above formulas (1) to (3), thereby deforming due to thermal stress or contact surface pressure. A support roll with a longer service life can be realized.

  In addition, the slit width a, the slit depth d, and the slit pitch p can be calculated by numerical analysis using FEM, for example. Specifically, a calculation model simulating a support roll on which slit portions having a predetermined slit width a, slit depth d, and slit pitch p are formed as initial values is created. And in the state which gave external force (for example, rolling force, contact surface pressure, etc.) which can be actually loaded in a continuous casting process, and a heat source (slab 3) with respect to the calculation model, in FEM Temperature distribution, stress distribution (including thermal stress), deformation amount (including deformation due to thermal expansion), etc. are calculated. Slit width a, slit depth d and slit satisfying the above formulas (1) to (3) by repeating the calculation while appropriately changing the values of slit width a, slit depth d and slit pitch p. The value of the pitch p can be determined.

  An embodiment in which the support roll according to the present invention is applied to a continuous casting machine will be described. As an example, the support roll 10a formed with the wedge-shaped slit portion 123a shown in FIG. 7 was applied to the continuous casting machine 20 shown in FIG. 1, and continuous casting was performed under the following use conditions.

Casting speed: 2.0 (mpm)
Period of use: 7 (years)
Cooling water volume: 45 (l / min)
Support roll axial length: 2500 (mm)
Support roll diameter: 400 (mm) (Roll diameter of shaft member: 350 (mm))
Support roll slit pitch: 15 (mm)
Slab temperature: 900 (degrees) or more

  In addition, as examples, the surface material of the roll member 121a is stainless steel (Example 1), the surface material of the roll member 121a is cemented carbide (Example 2), and two types of support. Continuous casting was performed using the roll 10a. As a comparative example, the conventional support roll described in Patent Document 1 was also continuously cast under the same use conditions as described above. The structure of the support rolls in Comparative Example, Example 1 and Example 2 are summarized in Table 1 below.

  About these comparative examples, Example 1, and Example 2, after performing continuous casting on the said use conditions, the presence or absence of the generation | occurrence | production of the thermal crack in the support roll surface and the amount of radial wear were investigated. First, regarding the presence or absence of occurrence of thermal cracks, thermal cracks on the surface of the support roll after use were not confirmed in all of Comparative Example, Example 1 and Example 2. From the results, it was found that the generation of thermal cracks was suppressed by the support roll 10a according to the present embodiment as well as the support roll described in Patent Document 1 as a comparative example. This is considered because the thermal expansion in the support roll 10a is absorbed by the slit portion 123a formed on the surface of the support roll 10a, and the thermal stress is relieved.

  Next, the amount of wear in the radial direction of the support roll after use in the comparative example, example 1 and example 2 will be described with reference to FIG. FIG. 11 is a graph showing the amount of wear in the radial direction of the support roll after use in Comparative Example, Example 1 and Example 2. As shown in FIG. 11, in the comparative example using the conventional support roll, the amount of wear in the radial direction was about 1.2 (mm). On the other hand, in Example 1 using the support roll 10a according to the present embodiment, the amount of wear in the radial direction is about 0.8 (mm), and it has been confirmed that the amount of wear is reduced compared to the conventional case. It was. In Example 1, since the slit width is formed smaller than that in the comparative example, it is considered that the contact surface pressure on the surface of the support roll 10a can be reduced, and the amount of wear is reduced.

  Further, as shown in FIG. 11, in Example 2 in which the support roll 10a according to the present embodiment is made of super hard material as the material of the roll member 121a, the radial wear amount is about 0.05 ( mm), and it was confirmed that the wear amount was further reduced as compared with Example 1. Thus, by using a super hard material as the material of the roll member 121a, the wear on the surface of the support roll 10a is further suppressed, and the service life of the support roll 10a can be further extended.

  In the above, the Example which applied the support roll which concerns on this invention to the continuous casting machine was demonstrated. As described above, it has been found that by applying the support roll according to the present invention to a continuous casting machine, it is possible to reduce the amount of wear on the surface of the support roll while suppressing the occurrence of thermal cracks. Therefore, according to the present invention, the service life of the support roll can be further extended. As described above, the support roll according to the present invention can be suitably applied to a process in which a larger thermal load can be applied to the support roll, such as a continuous casting process.

<5. Supplement>
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above, although the embodiment in which the support roll according to the present invention is applied to the continuous casting process has been described, the present invention is not limited to such an example. The support roll according to the present invention is a process in which a metal material is supported and transported by the support roll and is a process in which a thermal load is applied from the metal material to the support roll. Is applicable. Even when the support roll according to the present invention is applied to such other processes, the same effects as described above can be obtained.

10, 10a, 10b, 10c Support roll 20 Continuous casting machine 110 Shaft member 120, 120a, 120b, 120c Roll part 121, 121a, 121b, 121c Roll member 122, 122a, 122b, 122c Opening part 123, 123a, 123b, 123c Slit part 124 Thin part

Claims (2)

A support roll for supporting and transporting a metal material,
A shaft member extending in the rotation axis direction of the support roll;
A plurality of roll members having an annular shape fitted to the shaft member and arranged in the rotation axis direction;
With
In the region having a predetermined length in the radial direction including the outer edge portion of the roll member, a thin portion having a thinner thickness in the rotation axis direction than the other region is formed,
In a region corresponding to the thin portion between the opposing surfaces of the roll members adjacent in the rotation axis direction , a slit portion is provided,
The ratio of the radial depth of the slit part to the width of the slit part in the outer peripheral part of the roll member is 10 or more . The shape of the slit portion in the cross section in the radial direction of the support roll is a wedge shape in which the width of the slit portion uniformly decreases toward the inside in the radial direction.
The support roll according to claim 1, wherein

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