JP2008260047A - Apparatus and method for cooling roll of rolling mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve cooling ability in cooling a roll of a rolling mill. <P>SOLUTION: Colliding portions 6 of the outer surface of the roll R with the cooling water jetted from full cone nozzles are arranged in a row in the axial direction of the roll R. The colliding portions 6 arranged in a row are provided in four steps in the rotational direction of the roll R. The respective colliding portions 6 in neighboring steps are arranged in a zigzag manner. A plurality of colliding portions 7 with the cooling water jetted from flat nozzles are provided below the colliding portions 6 with the cooling water jetted from the full cone nozzles so as to be arranged in the axial direction of the roll R. The colliding portions 7 are tilted downward from the central portion C of the roll R in the axial direction toward the end portions E. The colliding portions 7 are arranged along the outer surface of the roll R so as not to form gaps in the axial direction of the roll R in a view from above. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling mill roll cooling device and a cooling method thereof.

  Since the roll for rolling mills is used, for example, for rolling a high-temperature rolled material, cooling corresponding to the amount of heat input from the rolled material is required. In recent years, the amount of heat generated during the processing of rolled material has increased due to shortening the interval at which the rolled material is carried into the rolling mill in order to improve the productivity of the rolled material, or to increase the strength of the rolled material. Therefore, the amount of heat input to the roll for the rolling mill is increasing. Therefore, improvement of the cooling capacity of a roll is calculated | required.

  With regard to cooling of the rolling mill roll, conventionally, for example, as shown in FIG. 15, a header 100 for supplying cooling water and a spray nozzle 101 for injecting cooling water to the outer surface of the roll R are provided. Cooling devices have been proposed. For example, a flat nozzle is used as the spray nozzle 101. In the present cooling device, the distance between the roll R and the spray nozzle 101 or the roll so that the cooling capacity of the roll R is close to the peak value with respect to an arbitrary nozzle flow density of the cooling water sprayed from the spray nozzle 101. The installation interval of the spray nozzle 101 in the R-axis direction is set (Patent Document 1).

JP 2000-71004 A

  Generally, when determining the cooling capacity of the roll R by the spray nozzle 101, the collision area on the outer surface of the roll R of the cooling water sprayed from the spray nozzle 101 is a major factor that affects the cooling capacity. However, when a flat nozzle is used for the spray nozzle 101 as in the prior art, the spread angle α in the longitudinal direction of the cooling water sprayed from the spray nozzle 101 is large as shown in FIG. Is extremely small. For this reason, the cooling water sprayed from the spray nozzle 101 collides with the outer surface of the roll substantially linearly, and the collision area becomes small. Therefore, the cooling capacity of the roll R by the spray nozzle 101 is not so high, and the roll R cannot be efficiently cooled.

  This invention is made | formed in view of this point, and it aims at cooling the said roll efficiently, when cooling water is injected and the roll for rolling mills is cooled.

  In order to achieve the above object, the cooling device of the present invention is a cooling device for injecting cooling water onto a roll for a rolling mill to cool the roll, and injecting the cooling water, outside the cooling water roll. A plurality of full cone nozzles arranged so that a plurality of collision portions on the surface are arranged in the roll axis direction, and cooling water is jetted below the collision portions of the cooling water from the plurality of full cone nozzles. A plurality of flat nozzles arranged so that a plurality of collision portions on the outer surface of the roll are arranged in the roll axis direction, and each collision portion of the cooling water from the plurality of flat nozzles is horizontal or inclined It is characterized by.

  When the full cone nozzle and the flat nozzle are arranged at the same distance from the roll and the cooling water is sprayed from the respective nozzles onto the outer surface of the roll, the cooling water sprayed from the full cone nozzle is cooled by the flat nozzle. The collision pressure on the outer surface of the roll is smaller than that of water, but the collision area is increased. The collision area of the cooling water greatly contributes to the determination of the roll cooling capacity by the nozzle rather than the collision pressure. Therefore, the full cone nozzle having a large collision area has a higher cooling capacity than the flat nozzle. In the present invention, since a full cone nozzle is used, the ability to cool the roll is improved compared to the case of using a conventional flat nozzle, and the roll can be cooled efficiently. Therefore, since the temperature drop of the roll becomes faster, the interval of the rolled material carried into the roll of the rolling mill can be shortened, and the productivity of the rolled material can be improved. The shape and thickness accuracy of the material can be improved. Furthermore, since the time for which the roll is heated is shortened, the replacement frequency of the roll can be reduced.

  By the way, when a full cone nozzle is used instead of the flat nozzle, the cooling water sprayed from the full cone nozzle does not have a sufficient speed component in the roll axis direction on the outer surface of the roll, and is thus not easily discharged in the roll axis direction. . For this reason, a large amount of cooling water flows down along the outer surface of the roll, and there is a concern that the cooling water leaks from the gap between the draining plate and the roll and falls on the rolled material, for example. . According to the present invention, in the lower part of the collision part of the cooling water ejected from the plurality of full cone nozzles, each collision part of the cooling water ejected from the plurality of flat nozzles is horizontally or inclined in the roll axis direction. Multiple items are arranged. Since the cooling water from the plurality of flat nozzles has a large velocity component in the roll axis direction on the outer surface of the roll, the drainage capacity in the roll axis direction is high. Thereby, the cooling water sprayed from the full cone nozzle is discharged in the roll axis direction by the cooling water from the flat nozzle having a large velocity component in the roll axis direction after colliding with the outer surface of the roll. As a result, the amount of cooling water falling on the draining plate below the roll is reduced, and for example, it is possible to prevent cooling water from leaking from the draining plate and falling onto the rolled material. As described above, according to the cooling device of the present invention, the cooling capacity of the roll from the full cone nozzle is improved by improving the cooling capacity of the roll as compared with the conventional case by injecting the cooling water from the full cone nozzle to the roll. The cooling water colliding portion from the flat nozzle is disposed below, and the cooling water drainage can be secured.

  The collision part of the cooling water from the plurality of flat nozzles may be arranged so that there is no gap in the roll axis direction when viewed from above along the outer surface of the roll. As a result, most of the cooling water sprayed from the full cone nozzle to the roll can be discharged to the end in the roll axial direction. In addition, in order to discharge such cooling water, a flat nozzle is used in which the collision portion on the outer surface of the cooling water roll is linear. Therefore, by arranging a small number of flat nozzles, The collision part can be arranged without a gap in the roll axis direction.

  Each collision part of the cooling water from the plurality of flat nozzles may be inclined so that the end side is lower than the center part side in the axial direction of the roll, and conversely, the cooling water from the plurality of flat nozzles Each collision part may incline so that the edge part side may become higher than the center part side of the axial direction of a roll. Moreover, each collision part of the cooling water from the plurality of flat nozzles may be inclined so that one end side in the roll axis direction is lower than the other end part side. Thereby, the cooling water sprayed from the full cone nozzle flows more reliably to the axial end of the roll.

  The collision portions of the cooling water from the plurality of flat nozzles are horizontal, and the collision portions of the cooling water from the plurality of flat nozzles arranged in the roll axis direction are arranged in a plurality of rows adjacent to each other in the roll rotation direction. The collision part may be shifted up and down along the outer surface of the roll, and ends of the adjacent collision parts may overlap each other when viewed from above along the outer surface of the roll.

  The collision parts of the cooling water from the full cone nozzle may be arranged in a line in the roll axis direction, and the collision parts arranged in the line may be arranged in multiple stages in the roll rotation direction.

  Each collision part of the step adjacent to the cooling water from the full cone nozzle may be arranged in a staggered manner. In addition, each collision part of the step which the cooling water from a full cone nozzle adjoins may overlap, seeing from upper direction along a roll outer surface.

  The full cone nozzle may be inclined outward from the axial center of the roll to inject cooling water.

  Another aspect of the cooling method of the present invention is a cooling method in which cooling water is injected onto a roll for a rolling mill to cool the roll, and the cooling water is injected from a plurality of full cone nozzles onto the outer surface of the roll. The cooling water sprayed from the plurality of full cone nozzles, after colliding with the outer surface of the roll, is poured out in the end direction in the roll axis direction by the cooling water sprayed from the plurality of flat nozzles. Yes.

  According to the present invention, when cooling a roll for a rolling mill by injecting cooling water, the cooling capacity is improved by using a cooling device having a full cone nozzle, and the roll can be efficiently cooled. .

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is a configuration diagram showing an outline of the configuration of the cooling device 1 according to the present embodiment, and FIG.

  As shown in FIGS. 1 and 2, the cooling device 1 includes a header 2 that extends in the axial direction of an upper roll R that rolls the rolled material S. The header 2 has a circular tube shape through which cooling water flows, and is connected to a cooling water supply source (not shown). The header 2 is installed in a plurality of stages, for example, five stages in the rotation direction of the roll R, on the side of the roll R in the conveyance direction of the rolled material S. The five-stage header 2 is supported by the frame 3 at both ends.

  Among the five-stage header 2, a plurality of full cone nozzles 4 are arranged in the axial direction of the header 2 in the header 2 from the top to the first to fourth stages. As shown in FIG. 3, the full cone nozzle 4 is arranged such that the inclination angle θ between the central axis of the full cone nozzle 4 and the perpendicular to the outer surface of the roll R is within 5 degrees in the vertical direction. Further, as shown in FIG. 4, the central axis of the full cone nozzle 4 is in the same direction as the vertical line of the outer surface of the roll R in the horizontal direction. As shown in FIG. 5, the full cone nozzle 4 can inject cooling water in a conical shape with respect to the roll R so that the cooling water spread angle α is within 40 degrees. As shown in FIG. 6, the cooling water sprayed from the full cone nozzle 4 forms a circular collision portion 6 on the outer surface of the roll R.

  Among the five headers 2 described above, the lowermost header 2 has a plurality of flat nozzles 5 arranged in the axial direction of the header 2 as shown in FIGS. 1 and 2. The cooling water sprayed from the flat nozzle 5 forms a linear collision portion 7 on the outer surface of the roll R as shown in FIG.

  Below the flat nozzle 5, as shown in FIG. 1, a draining plate 8 extending in the roll R axis direction along the outer surface of the roll R is provided. The tip of the draining plate 8 is sharpened along the outer surface of the roll R.

  Next, arrangement | positioning of the collision parts 6 and 7 in the outer surface of the roll R of the cooling water sprayed from the full cone nozzle 4 and the flat nozzle 5 is demonstrated. As shown in FIG. 6, a plurality of collision portions 6 of the cooling water sprayed from the full cone nozzle 4 are arranged in a row in the roll R axis direction, and the collision portions 6 arranged in the row are arranged in the roll R rotation direction. Four stages are provided. Each collision part 6 of the adjacent step | line is arrange | positioned at zigzag form.

  A plurality of cooling water collision portions 7 from the flat nozzle 5 are arranged in the roll R axis direction below the cooling water collision portion 6 from the full cone nozzle 4. The collision portion 7 is inclined downward from the center portion C in the axial direction of the roll R toward the end portion E side. Moreover, the collision part 7 is arrange | positioned so that there may be no clearance in the roll R axial direction seeing from the upper direction along the outer surface of the roll R.

  The cooling device 1 according to the present embodiment is configured as described above. Next, a method for cooling the roll R using the cooling device 1 will be described.

  When the roll R starts to rotate in order to roll the rolled material S, cooling water is supplied to the header 2. Then, cooling water is jetted from the full cone nozzle 4 and the flat nozzle 5 onto the outer surface of the roll R. At this time, as shown in FIG. 6, the collision part 6 of the cooling water ejected from the full cone nozzle 4 has a circular shape, the collision part 7 of the cooling water ejected from the flat nozzle 5 has a straight shape, and the roll R It inclines below toward the edge part E side from the center part C of the axial direction.

  The cooling water sprayed from each full cone nozzle 4 collides with the outer surface of the roll R, and then flows down along the outer surface of the roll R while cooling the roll R. The roll R is cooled with a high cooling capacity by the cooling water from the full cone nozzle 4. Thereafter, the cooling water falls onto the cooling water flow ejected from the flat nozzle 5. Then, the cooling water from the full cone nozzle 4 flows to the end E side in the roll R axis direction and is discharged by the flow of the cooling water flow injected from the flat nozzle 5 in the roll axis direction. The cooling water sprayed from the flat nozzle 5 also cools the roll R after colliding with the outer surface of the roll R. A part of the cooling water flows in the axial direction of the roll R together with the cooling water from the full cone nozzle 4 as described above, and is discharged from the end E in the axial direction of the roll R. Further, the remaining cooling water from the flat nozzle 5 falls onto the lower draining plate 8 and is discharged from the side of the draining plate 8.

  According to the above embodiment, since the full cone nozzle 4 having a higher cooling capacity than the conventionally used flat nozzle is provided, the ability to cool the roll R is improved compared to the conventional one, and the roll R is efficiently cooled. be able to. Therefore, since the temperature drop of the roll R is accelerated, the interval of carrying the rolled material S rolled by the roll R into the rolling mill can be shortened, and the productivity of the rolled material S can be improved. Since the cooling of the material is stabilized and the thermal expansion of the roll R is suppressed, the shape and thickness accuracy of the rolled material S can be improved. Further, since the time during which the roll R is heated is shortened, material deterioration of the surface of the roll R is suppressed, and the replacement frequency of the roll R can be reduced. Further, since the cooling water collision portion 7 of the flat nozzle 5 is arranged along the roll R axis direction below the cooling water collision portion 6 of the full cone nozzle 4, the cooling injected from the flat nozzle 5 is performed. The cooling water sprayed from the full cone nozzle 4 can be discharged to the end of the roll R in the axial direction by water. As described above, according to the cooling device 1 of the present embodiment, the cooling capacity of the roll R is improved by injecting the cooling water from the full cone nozzle 4 to the roll R, and the full cone nozzle 4 The cooling water collision part 7 from the flat nozzle 5 can be arranged below the cooling water collision part 6 to ensure the drainage of the cooling water.

  Here, it is verified that the roll cooling capacity of the full cone nozzle is higher than that of the flat nozzle. As shown in FIG. 7, when the cooling water is sprayed onto the outer surface of the roll R as the finishing roll, the cooling of the roll R by the respective nozzles 10 when the full cone nozzle is used and when the flat nozzle is used. Compare abilities. In this experiment, a plurality of nozzles 10 are arranged in the axial direction of the header 2, the header 2 has three stages on the roll R side in the conveying direction of the rolled material S, and on the opposite side of the roll R in the conveying direction of the rolled material S. One stage is provided. Below the nozzle 10, a draining plate 8 is provided. FIG. 8 shows the result of comparison of the cooling capacity of the roll R by the nozzle 10. 8A is a graph showing the cooling capacity when the rotation speed of the roll R is 50 rpm (120 mpm), and FIG. 8B is a graph showing the cooling capacity when the rotation speed of the roll R is 200 rpm (500 mpm). As the cooling capacity, when the roll R is cooled from 550 ° C. to 450 ° C., the average cooling rate on the outer surface of the roll R is measured. In this experiment, the temperature of the cooling water flowing through the header 2 is set to 21 to 24 ° C., and the pressure of the cooling water is changed to 1 MPa and 1.5 MPa.

  Referring to FIGS. 8A and 8B, even if the pressure of the cooling water flowing through the header 2 is changed or the number of rotations of the roll R is changed, the full cone nozzle is used rather than the flat nozzle. It can also be seen that the cooling capacity is increased. This is because the collision area on the roll R of the cooling water (broken line in FIG. 7) ejected from the full cone nozzle is larger than the collision area on the roll R of the cooling water (dotted line in FIG. 7) ejected from the flat nozzle. This is probably because the collision angle is small.

  Further, referring to FIGS. 8A and 8B from another viewpoint, when the full cone nozzle is used, even if the pressure of the cooling water flowing through the header 2 is reduced, the cooling capacity is reduced due to the change in the water pressure. I understand that there are few. This means that when a full cone nozzle is used, a high cooling capacity can be maintained even if the water pressure is reduced. Therefore, it can be seen that by using the full cone nozzle, energy saving can be achieved by reducing the water pressure. Furthermore, it can also be confirmed that when the number of rotations of the roll R is increased, the cooling capability of the full cone nozzle is improved.

  Moreover, as shown in FIG. 9, when injecting cooling water to the outer surface of the roll R as a rough roll, the case of using a full cone nozzle and the case of using a flat nozzle depend on the respective nozzles 10. The cooling capacity of the roll R is compared. In this experiment, a plurality of nozzles 10 are arranged in the axial direction of the header 2, and the header 2 is provided in one stage on the roll R side in the conveying direction of the rolled material S. FIG. 10 shows the result of comparison of the cooling capacity of the roll R by the nozzle 10. As the cooling capacity, when the roll R is cooled from 550 ° C. to 450 ° C., the average cooling rate on the outer surface of the roll R is measured. In this experiment, the temperature of the cooling water flowing through the header 2 is 27 to 30 ° C., and the pressure of the cooling water is changed to 0.3 MPa and 0.5 MPa. The rotation speed of the roll R is 107 rpm (270 mpm). Also in this case, the collision area on the roll R of the cooling water (broken line in FIG. 9) ejected from the full cone nozzle is larger than the collision area on the roll R of the cooling water (dotted line in FIG. 9) ejected from the flat nozzle. Therefore, it can be seen that the cooling capability is improved when the full cone nozzle is used rather than when the flat nozzle is used.

  According to the present embodiment, since the cooling water colliding portion 7 from the flat nozzle 5 is arranged so as not to have a gap in the roll R axis direction, the cooling water jetted from the full cone nozzle 4 to the roll R. Is more reliably discharged from the end E of the roll R. For this reason, the cooling water falling on the draining plate 8 installed below the flat nozzle 5 is reduced, and the load on the draining plate 8 can be reduced. Further, the cooling water that is sprayed from the flat nozzle 5 onto the roll R and falls downward flows to the end E in the roll R axis direction by the draining plate 8 and is discharged. Thus, since the cooling water sprayed from the full cone nozzle 4 and the flat nozzle 5 does not fall on the rolling material S conveyed below the roll R, the rolling material S can be appropriately rolled. .

  Furthermore, since the collision part 7 of the cooling water from the flat nozzle 5 is inclined downward from the central part C in the axial direction of the roll R toward the end E side, the cooling water is directed in the axial direction of the roll R. Therefore, the cooling water sprayed from the full cone nozzle 4 to the roll R can be discharged and discharged more reliably to the end E in the roll R axial direction.

  In the above embodiment, the collision portion 7 of the cooling water from the flat nozzle 5 is inclined downward from the central portion C in the axial direction of the roll R toward the end portion E side, as shown in FIG. In addition, the collision part 7 may be horizontal. In this case, the adjacent collision parts 7 and 7 are shifted up and down along the outer surface of the roll R, and the ends of the adjacent collision parts 7 and 7 are directed upward along the outer surface of the roll R. It overlaps when seen from. As shown in FIG. 12, the collision part 7 may be inclined downward toward one end E side of the roll R, and the collision part 7 is arranged in the axial direction of the roll R as shown in FIG. You may incline upwards from the center part C toward the edge part E side. Also in such an example, the cooling water sprayed from the full cone nozzle 4 and falling downward flows to the end E in the roll R axis direction and is discharged by the cooling water sprayed from the flat nozzle 5.

  In the above embodiment, the central axis of the full cone nozzle 4 is in the same direction as the vertical line of the outer surface of the roll R, but as shown in FIG. It may be inclined outward from C. In this case, the central axis of the full cone nozzle 4 on the one end E1 side from the central portion of the roll R in the axial direction has an inclination angle φ with the perpendicular of the outer surface of the roll R within 5 degrees in the horizontal direction. Are inclined toward the end E1 of the roll R. Further, the center axis of the full cone nozzle 4 on the other end E2 side from the center in the axial direction of the roll R is inclined toward the end E2 side of the roll R. According to such an example, since the cooling water is inclined and sprayed toward the ends R1 and E2 in the roll R axial direction from the full cone nozzle 4 toward the roll R, it is lowered downward after colliding with the outer surface of the roll R. The falling cooling water can be more reliably flowed to the ends E1 and E2 in the roll R axis direction.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be made within the scope of the ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  The present invention is useful for a rolling device roll cooling device and a cooling method thereof.

It is a block diagram which shows the outline of a structure of the cooling device concerning this Embodiment. It is a side view of the cooling device concerning this embodiment. It is the side view which showed the direction of the full cone nozzle with respect to a roll. It is the top view which showed direction of the full cone nozzle with respect to a roll. It is explanatory drawing which showed a mode that cooling water was injected from a full cone nozzle. It is the side view of the roll which showed the collision part in the roll outer surface of the cooling water sprayed from the full cone nozzle and the flat nozzle. It is a block diagram which shows the outline of a structure of the cooling device for the experiment which compares the cooling performance of a full cone nozzle and a flat nozzle. It is a graph of a comparison result about the cooling performance of a full cone nozzle and a flat nozzle. It is a block diagram which shows the outline of a structure of the cooling device for the experiment which compares the cooling performance of a full cone nozzle and a flat nozzle. It is a graph of a comparison result about the cooling performance of a full cone nozzle and a flat nozzle. It is the side view of the roll which showed the collision part in the roll outer surface of the cooling water sprayed from the full cone nozzle and the flat nozzle. It is the side view of the roll which showed the collision part in the roll outer surface of the cooling water sprayed from the full cone nozzle and the flat nozzle. It is the side view of the roll which showed the collision part in the roll outer surface of the cooling water sprayed from the full cone nozzle and the flat nozzle. It is the top view which showed direction of the full cone nozzle with respect to a roll. It is a block diagram which shows the outline of a structure of the conventional cooling device. It is explanatory drawing which showed a mode that cooling water was injected from a flat nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling device 2 Header 4 Full cone nozzle 5 Flat nozzle 6 Colliding part 7 Colliding part 8 Draining board

Claims (10)

A cooling device that cools the roll by spraying cooling water onto the roll for a rolling mill,
A plurality of full cone nozzles arranged to inject cooling water, and a plurality of colliding portions on the outer surface of the cooling water roll are arranged in the roll axis direction;
A plurality of flat nozzles arranged to inject cooling water, and a plurality of colliding portions on the outer surface of the cooling water roll are arranged in the roll axis direction below the colliding portions of the cooling water from the plurality of full cone nozzles, Have
The cooling device for a roll for a rolling mill, wherein each collision portion of the cooling water from the plurality of flat nozzles is horizontal or inclined. The collision part of the cooling water from the plurality of flat nozzles is arranged so that there is no gap in the roll axial direction when viewed from above along the outer surface of the roll. The rolling mill roll cooling device described. The rolling according to claim 1 or 2, wherein each collision portion of the cooling water from the plurality of flat nozzles is inclined so that the end portion side is lower than the central portion side in the axial direction of the roll. Machine roll cooling device. The rolling according to claim 1 or 2, wherein each collision portion of the cooling water from the plurality of flat nozzles is inclined so that the end portion side is higher than the central portion side in the axial direction of the roll. Machine roll cooling device. Each collision part of the cooling water from the plurality of flat nozzles is inclined so that one end side in the axial direction of the roll is lower than the other end part side. The rolling device roll cooling device according to claim 1. Each collision part of the cooling water from the plurality of flat nozzles is horizontal,
The collision portions of the cooling water from the plurality of flat nozzles arranged in the roll axis direction are arranged in a plurality of rows in the roll rotation direction,
Adjacent collision parts are shifted up and down along the outer surface of the roll, and ends of the adjacent collision parts overlap each other when viewed from above along the outer surface of the roll. The rolling device roll cooling device according to claim 2. The collision parts of the cooling water from the full cone nozzle are arranged in a line in the roll axis direction, and the collision parts arranged in the line are arranged in multiple stages in the roll rotation direction. The cooling apparatus of the roll for rolling mills in any one of 1-6. The rolling device roll cooling device according to claim 7, wherein the collision portions of adjacent stages of cooling water from the full cone nozzle are arranged in a staggered manner. The cooling device according to any one of claims 1 to 8, wherein the full cone nozzle is inclined outward from an axial center portion of the roll to inject cooling water. A cooling method in which cooling water is sprayed onto a roll for a rolling mill to cool the roll,
Inject cooling water to the outer surface of the roll from multiple full cone nozzles,
The cooling water sprayed from the plurality of full cone nozzles, after colliding with the outer surface of the roll, is poured out in the end direction in the roll axis direction by the cooling water sprayed from the plurality of flat nozzles. The cooling method of the roll for rolling mills.

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