Casting roller and using method thereof

Abstract

The invention discloses a casting roller and a using method thereof. The common problem that in the prior art, due to the fact that an external nozzle sprays water to cool the casting roller, a slab cracks is solved. The casting roller is provided with a center hole and bypass holes, cooling water flows through the center hole and the bypass holes, the center hole and the bypass holes are arranged in a penetrating mode, the axis of the center hole coincides with the axis of the casting roller, the multiple bypass holes are arranged, the axes of the multiple bypass holes are parallel to the center hole, and the multiple bypass holes are evenly arranged outside the center hole in a surrounding mode; wherein the distance between the central axis of the bypass hole and the peripheral surface of the casting roller is L, and the ratio of the radius of the casting roller to the L is 5.5-6.2. A plate blank pressed by the casting roller is free of cracks, the requirement for the pressing amount is met, and the service life of the casting roller is long.

Description

Technical Field

[0001] The present application belongs to the field of continuous casting technology, and specifically relates to a casting roll and a method of using the same. Background Art

[0002] The casting roll is the main equipment for single-pass high-pressure reduction of slabs in the secondary cooling zone of continuous casting. It is usually installed separately in a certain sector at the solidification end of the continuous casting machine. The casting roll is different from the sector casting roll 300 of the continuous casting machine (see Figure 1 ) is different from the continuous casting machine. The diameter of the casting roll is large, similar to the rolling roll for steel rolling. Since there is a large temperature difference between the surface and the thickness center of the slab during the continuous casting process, the temperature difference in the solidification end area can reach more than 400°C. Taking advantage of this natural temperature advantage, the large-diameter casting roll can effectively apply a single-point large reduction (≥10mm) to the slab at the end of solidification in the second cooling zone, so that the reduction force can efficiently penetrate into the center of the slab, greatly improving the shrinkage and loose defects in the center of the casting. The light reduction and large reduction principles and working methods of the casting roll 300 of the casting machine itself are different. Light reduction is to implement continuous reduction in multiple fan-shaped segments as the slab solidifies, mainly to solve the problem of central element segregation in the solidification process of the slab. The light reduction is small, only 0.5-1mm / m, and the total reduction is 4-9mm. Large reduction is mainly aimed at solving the shrinkage and loose defects in the center of the slab, while light reduction is mainly to solve the segregation of central elements.

[0003] The roller diameter of the casting roller is ≥500mm, which is much larger than the roller diameter of the casting roller of the slab continuous casting machine itself, and the single-point maximum reduction of the casting roller on the slab is ≥10mm. When the slab passes through the casting roller, the heat of the slab will be transferred to the casting roller, causing the casting roller to heat up. Coupled with the effect of high load, the strength and service life of the casting roller are seriously affected.

[0004] Currently, see Figure 1 , the casting rolls are mostly cooled by spraying cooling water with nozzles 400. During the continuous casting process, the casting rolls are in continuous contact with the slab surface under high pressure. A large amount of external cooling water drips and accumulates on the slab surface, causing the slab surface to be locally overcooled and enter the high-temperature brittle zone of the steel. When high pressure is applied, crack defects will be caused on the slab surface. Summary of the invention

[0005] Based on the simulation of temperature field and stress field of casting rolls in different cooling modes, a casting roll and its use method are obtained, which can not only ensure efficient cooling of large roll diameter casting and rolling, but also solve the problem of surface cracks of slabs.

[0006] In a first aspect of the present application, a casting roll is provided, wherein the casting roll is provided with a center hole and a bypass hole for cooling water to flow, the center hole and the bypass hole are both through-set, the center hole coincides with the axis of the casting roll, a plurality of the bypass holes are provided, the axes of the plurality of bypass holes are parallel to the center hole, and the bypass holes are evenly arranged outside the center hole;

[0007] Wherein, the distance between the central axis of the bypass hole and the outer peripheral surface of the casting roller is L, and the ratio of the radius of the casting roller to the L is 5.5-6.2.

[0008] In some embodiments, the ratio of the radius of the casting roll to the radius of the bypass hole is 18.6-19.5.

[0009] In some embodiments, a ratio of the radius of the casting roll to the number of the bypass holes is 40.9-65.

[0010] In some embodiments, the ratio of the radius of the casting roll to the radius of the center hole is 15.6 to 16.5.

[0011] In some embodiments, the distance between the central axis of the bypass hole and the outer peripheral surface of the casting roller is L, and the ratio of the radius of the casting roller to L is 5.5-6.

[0012] In some embodiments, the diameter of the casting roll is 500-1500 mm.

[0013] In some embodiments, the diameter of the casting roll is 500 mm, the radius of the bypass hole is 13 mm, the radius of the center hole is 15 mm, and the number of the bypass holes is 6.

[0014] In some embodiments, the distance between the central axis of the bypass hole and the outer circumferential surface of the casting roll is 45 mm.

[0015] In the second aspect of the present application, there is provided a method for using the casting roll of the first aspect, wherein when the casting roll applies a large reduction of ≥10 mm to the slab, cooling water is introduced into the center hole and the bypass hole, wherein the cooling water in the center hole and the bypass hole have the same flow direction, the cooling water flow rate in the center hole is 50-300 L / min, and the total cooling water flow rate in the bypass hole is 200-1000 L / min.

[0016] In some embodiments, the cooling water flow rates in the plurality of bypass holes are the same.

[0017] According to a casting roller and a method for using the same provided in an embodiment of the present application, the casting roller is provided with a center hole and a bypass hole, both of which are used for circulating cooling water, the center hole is arranged through, the center hole coincides with the axis of the casting roller, the bypass hole is arranged through, the axes of the plurality of bypass holes are parallel to the center hole and are evenly arranged outside the center hole, the distance between the center axis of the bypass hole and the outer peripheral surface of the casting roller, that is, the roller surface, is L, and the ratio of the radius of the casting roller to the L is 5.5 to 6.2.

[0018] The center hole and the bypass hole are connected, so the cooling water in the center hole and the bypass hole can cool the inside of the casting roll, reduce the temperature of the casting roll, so that the casting roll still has high strength and is not easy to deform when the slab passes through, so as to ensure that the slab can be pressed down to a large extent. The ratio of the radius of the casting roll to the L is controlled to be 5.5-6.2, so that the roller surface temperature of the casting roll is more uniform, so its strength uniformity is better and its fatigue life is longer.

[0019] Compared with the prior art of cooling the roller surface of the casting roller by nozzles, the present application adopts internal cooling channel cooling, and no cooling water will be spilled on the slab. The roller surface temperature of the casting roller is low and uniform, and the surface quality of the slab is high and free of cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure shows the assembly diagram of the casting roll and the nozzle in the related art.

[0021] Figure 2 An end view of a casting roll in an embodiment of the present application is shown.

[0022] Figure 3-Figure 6 The simulated temperature cloud diagram at different times in one rotation cycle of the casting roll in the large reduction process in Example 1 is shown.

[0023] Description of reference numerals:

[0024] 100-casting roller, 110-center hole, 120-bypass hole, 200-slab, 300-casting roller, 400-nozzle. DETAILED DESCRIPTION

[0025] In order to make the technical personnel in the technical field to which the present application belongs to understand the present application more clearly, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0026] The first embodiment of the present application provides a casting roller, which does not require external water spray cooling, and thus does not affect the surface quality of the slab. At the same time, it also enables the casting roller to have higher temperature uniformity to ensure high-temperature strength and achieve large reduction of the slab.

[0027] See also Figure 1 to Figure 2The casting roller 100 provided in the embodiment of the present application is provided with a center hole 110 and a bypass hole 120. The center hole 110 and the bypass hole 120 are both used for circulating cooling water. The cooling water can cool the casting roller 100 and reduce the temperature of the casting roller 100, so that the casting roller 100 still has high strength and is not easy to deform when the slab 200 passes through, so as to ensure that a large reduction is achieved on the slab 200.

[0028] The center hole 110 is provided through, and the center hole 110 coincides with the axis of the casting roll 100, so that the cooling water absorbs the heat transferred to the axis of the casting roll 100 and cools the center of the casting roll 100. The bypass holes 120 are provided through, and there are multiple, for example, five, six, ten, etc. The axes of the multiple bypass holes 120 are parallel to the center hole 110 and are evenly arranged outside the center hole 110, that is, the axes of the multiple bypass holes 120 are located on the same circumference with the axis of the casting roll 100 as the center. The cooling water flowing through the bypass holes 120 can cool the part of the casting roll 100 close to the outer circumference, so that the roller surface temperature of the casting roll 100 in contact with the slab 200 is low and uniform.

[0029] The distance between the center axis of the bypass hole 120 and the outer peripheral surface of the casting roller 100, that is, the roller surface, is L. The ratio of the radius of the casting roller 100 to the L is 5.5-6.2, such as 5.6, 5.7, 5.8, 5.9, 6.0 and 6.1, etc. This ratio can be called the distance coefficient. The distance coefficient is controlled to be 5.5-6.2 to ensure the cooling intensity of the roller surface and control the roller surface temperature to ≤200°C. If the distance coefficient is too large, the roller surface cooling is weak and the roller surface wears quickly. If the distance coefficient is too small, the roller surface cooling intensity is large and the internal cooling intensity of the casting roller is weak, which affects the overall service life of the casting roller 100.

[0030] In some embodiments, the ratio of the radius of the casting roller 100 to the radius of the bypass hole 120 is 18.6-19.5, for example, 18.7, 18.9, 19.2 and 19.4, etc. This ratio can be called the circumferential cooling coefficient. The circumferential cooling coefficient is controlled to be 18.6-19.5 to ensure the overall cooling strength of the casting roller and the rigidity of the casting roller. If the circumferential cooling coefficient is too large, the structural rigidity of the casting roller 100 is reduced, and there is a risk of fracture when the reduction amount is large. If the circumferential cooling coefficient is too small, the cooling intensity is insufficient and the service life of the casting roller 100 cannot be guaranteed.

[0031] In some embodiments, the ratio of the radius of the casting roll 100 to the number of the bypass holes 120 is 40.9-65, such as 41, 43, 45, 47, 49, 50, 52, 54, 55, 58, 60, 62 and 64, etc. This ratio can be called the circumferential distribution coefficient. The circumferential distribution coefficient is controlled to be 40.9-65. The appropriate number of bypass holes 120 ensures the overall cooling strength and uniformity of the roller circumference, thereby improving the service life of the casting roll 100. In the process of designing the casting roll 100, the diameter of the casting roll 100 is first determined. If the circumferential distribution coefficient is too large, it means that the diameter of the casting roll 100 is very large, and / or the number of bypass holes 120 is too small, the cooling strength is weak, and the working temperature of the casting roll 100 is high, which will reduce the structural rigidity of the casting roll 100, thereby reducing the service life of the casting roll 100. If the circumferential distribution coefficient is too small, it means that the diameter of the casting roller 100 is very small, and / or the number of bypass holes 120 is too large, the cooling intensity is good, the operating temperature of the casting roller 100 is low, and the temperature uniformity is good. However, if the number of bypass holes 120 is too large, the rigidity of the casting roller 100 will be reduced structurally, thereby reducing the service life of the casting roller 100.

[0032] In some embodiments, the ratio of the radius of the casting roll 100 to the radius of the center hole 110 is 15.6-16.5, such as 15.7, 15.9, 16.1, 16.2, 16.3 and 16.4, etc. This ratio can be called the central cooling coefficient. The central cooling coefficient is controlled to be 15.6-16.5 to improve the cooling intensity and temperature uniformity of the casting roll 100. If the central cooling coefficient is too large, it means that the radius of the casting roll 100 is large, and / or the radius of the center hole 100 is small, which will reduce the cooling effect of the casting roll 100, and the temperature is high during the working process, which reduces the rigidity of the casting roll 100. If the central cooling coefficient is too small, it means that the radius of the casting roll 100 is small, and / or the radius of the center hole 100 is large, which will structurally reduce the rigidity of the casting roll 100, thereby reducing the service life of the casting roll 100.

[0033] In some embodiments, the distance between the central axis of the bypass hole 120 and the outer peripheral surface of the casting roller 100 is L, and the ratio of the radius of the casting roller 100 to the L is 5.5-6, for example, 5.6, 5.7, 5.8 and 5.9, etc. This ratio can be called a distance coefficient. Controlling the distance coefficient to 5.5-6 can improve the cooling effect and temperature uniformity, thereby increasing the service life of the casting roller 100.

[0034] In some embodiments, the diameter of the casting roll 100 is 500 mm to 1500 mm, such as 600 mm, 700 mm, 800 mm, or 1200 mm. Generally, the diameter of the casting roll 100 is very large, and its temperature uniformity is very low.

[0035] In some embodiments, the diameter of the casting roll 100 is 500 mm, the radius of the bypass hole 120 is 13 mm, the radius of the center hole 110 is 15 mm, and the number of the bypass holes 120 is 6. In some embodiments, the distance between the center axis of the bypass hole 120 and the outer circumference of the casting roll 100 can be 45 mm.

[0036] The second aspect embodiment of the present application provides a method for using the casting roller 100 of any embodiment of the first aspect, the method comprising: when the casting roller 100 performs a large reduction of ≥10mm on the slab 200, cooling water is introduced into the center hole 110 and the bypass hole 120, wherein the cooling water in the center hole 110 and the bypass hole 120 have the same flow direction, the cooling water flow rate in the center hole 110 is 50-300L / min, and the total cooling water flow rate in the bypass hole 120 is 200-1000L / min.

[0037] The cooling water flows in the center hole 110 and the bypass hole 120 in the same direction, that is, the water inlet end of the center hole 110 and the water inlet end of the bypass hole 120 are both located on one side of the casting roller 100 along the axial direction, and the water outlet end of the center hole 110 and the water outlet end of the bypass hole 120 are both located on the other side of the casting roller 100 along the axial direction, which is convenient for installing the water tank mechanism for water inlet and outlet.

[0038] The cooling water flow in the center hole 110 and the bypass hole 120 should be appropriate. The heat flux value of heat transfer increases with the increase of cooling water flow. However, when the cooling water flow increases to a certain amount, the heat flux value basically no longer increases, and the heat transfer efficiency is close to the limit. Further increasing the cooling water is a waste of resources; too small cooling water flow will cause insufficient cooling intensity, resulting in insufficient roller cooling, affecting stiffness and service life.

[0039] The casting roller 100 provided in the embodiment of the present application is suitable for a slab 200 with a thickness of 250 to 600 mm, and the single-point reduction amount of the casting roller 100 on the slab is ≥10 mm.

[0040] The casting roll 100 and the method of using the same provided by the present invention are further described in detail below in conjunction with the embodiments.

[0041] Embodiment 1:

[0042] The continuous casting secondary cooling zone uses a casting roll 100 with a roll diameter of 500 mm to implement a single-point 10 mm large reduction on a slab 200 with a thickness of 250 mm. The dimensions of the center hole 110 and the bypass hole 120 of the casting roll 100 are as follows:

[0043] 1) The radius of the bypass hole 120 is 13 mm (the radius of the casting roll 100 is R = 250 mm, and the circumferential cooling coefficient A is 19.5)

[0044] 2) The radius of the center hole 110 is 15 mm (R = 250 mm, the center cooling coefficient B is 16.5)

[0045] 3) The number of bypass holes 120 is 6 (R = 250mm, circumferential distribution coefficient C is 40.9)

[0046] 4) The distance between the axis of the bypass hole 120 and the roller surface of the casting roller 100 is 45 mm (R = 250 mm, the distance coefficient D is 5.5)

[0047] During the implementation of the above scheme, the cooling water flow rate of the center hole 110 is 50 L / min, the total flow rate of the bypass hole 120 is 200 L / min, the cooling water flow rate of each bypass hole 120 is the same, the temperature inside the casting roller 100 during the large reduction process is below 150°C, the maximum temperature difference is 31°C, and the service life of the large reduction casting roller 100 is 3 million tons of steel, with a long life; the 10mm reduction is stable and smooth, and the incidence of surface cracks in the slab 200 is 0.

[0048] Embodiment 2:

[0049] The continuous casting secondary cooling zone uses a casting roll 100 with a roll diameter of 900 mm to implement a single-point 30 mm large reduction on a slab 200 with a thickness of 400 mm. The dimensions of the center hole 110 and the bypass hole 120 of the casting roll 100 are as follows:

[0050] 1) The radius of the bypass hole 120 is 24 mm (the radius of the casting roll 100 is R = 450 mm, and the circumferential cooling coefficient A is 19)

[0051] 2) The radius of the center hole 110 is 28 mm (R = 450 mm, the center cooling coefficient B is 16)

[0052] 3) The number of bypass holes 120 is 9 (R = 450mm, circumferential distribution coefficient C is 50)

[0053] 4) The distance between the axis of the bypass hole 120 and the roller surface of the casting roller 100 is 75 mm (R = 450 mm, the distance coefficient D is 6)

[0054] During the implementation of the above scheme, the cooling water flow rate of the center hole 110 is 150 L / min, the total flow rate of the bypass hole 120 is 600 L / min, the cooling water flow rate of each bypass hole 120 is the same, the temperature inside the casting roller 100 during the large reduction process is below 200°C, the maximum temperature difference is 35°C, and the service life of the large reduction casting roller 100 is 2.6 million tons, with a long life; the 20mm reduction is stable and smooth, and the incidence of surface cracks in the slab 200 is 0.

[0055] Embodiment 3:

[0056] The continuous casting secondary cooling zone uses a casting roll 100 with a roll diameter of 1500mm to implement a single-point 50mm large reduction on a slab 200 with a thickness of 600mm. The casting roll 100 adopts a cooling design of internal circumferential water holes + central axis water holes:

[0057] 1) The radius of the circumferential water hole is 40 mm (casting roll 100 radius R = 750 mm, circumferential cooling coefficient A is 18.6)

[0058] 2) The radius of the central axis water hole is 48mm (R = 750mm, the central cooling coefficient B is 15.6)

[0059] 3) The number of circumferential water holes is 12 (R = 750mm, circumferential distribution coefficient C is 65)

[0060] 4) The distance between the axis of the bypass hole 120 and the roller surface of the casting roller 100 is 121 mm (R = 750 mm, the distance coefficient D is 6.2)

[0061] During the implementation of the above scheme, the cooling water flow rate of the center hole 110 is 300L / min, and the flow rate of the bypass hole 120 is 1000L / min. The cooling water flow rates of each bypass hole 120 are the same. The temperature inside the casting roller 100 during the large reduction process is below 200°C, and the maximum temperature difference is 38°C. The service life of the large reduction casting roller 100 is 2 million tons, and the service life is long; the 50mm reduction is stable and smooth, and the incidence of surface cracks in the slab 200 is 0.

[0062] Comparative Example 1

[0063] Comparative Example 1 adopts a cooling method of spraying water on the roller surface of the casting roller 100. The roller diameter of the casting roller 100 is the same as that of Example 1, the reduction amount is the same as that of Example 1, the life of the casting roller 100 is about 500,000 tons, and the crack rate of the continuous casting slab 200 after large reduction is 35%.

[0064] Comparative Example 2

[0065] Comparative Example 2 adopts a cooling method of spraying water on the roller surface of the casting roller 100. The roller diameter of the casting roller 100 is the same as that of Example 2, and the reduction amount is the same as that of Example 2. Compared with the cooling method of using water cooling outside the roller, the life of the casting roller 100 is about 300,000 tons, and the crack rate of the continuous casting slab 200 after large reduction is 50%.

[0066] Comparative Example 3

[0067] Comparative Example 3 adopts a cooling method of spraying water on the roller surface of the casting roller 100. The roller diameter of the casting roller 100 is the same as that of Example 3, and the reduction amount is the same as that of Example 3. Compared with the cooling method of using water cooling outside the roller, the life of the casting roller 100 is about 300,000 tons, and the crack rate of the continuous casting slab 200 after large reduction is 60%.

[0068] The casting roll 100 provided in the present application has at least the following advantages:

[0069] (1) The casting roll 100 adopts a cooling method of internal circumferential bypass holes 120 + center holes 110, which fundamentally solves the problem of cooling water accumulation on the surface of the ingot caused by the external cooling method and eliminates crack defects in the ingot.

[0070] (2) The size, number and position of the cooling water holes of the casting roll 100 with different roll diameters are limited, which reduces the temperature of the casting roll 100 and improves the uniformity of the temperature on the circumference of the casting roll 100, so that the casting roll 100 maintains its rigidity and realizes the metallurgical function of large reduction of slab 200 ≥ 10 mm, thus realizing efficient cooling and long life of the casting roll 100 during the continuous casting large reduction process.

[0071] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0072] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0073] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0074] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0075] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A casting roll, characterized in that: The casting roll is provided with a center hole and a bypass hole for cooling water to flow, the center hole and the bypass hole are both through-going, the center hole coincides with the axis of the casting roll, a plurality of the bypass holes are provided, the axes of the plurality of the bypass holes are parallel to the center hole, and are evenly arranged outside the center hole; Wherein, the distance between the central axis of the bypass hole and the outer peripheral surface of the casting roller is L, and the ratio of the radius of the casting roller to the L is 5.5-6.

2.

2. The casting roll according to claim 1, characterized in that: The ratio of the radius of the casting roll to the radius of the bypass hole is 18.6 to 19.

5.

3. The casting roll according to claim 2, characterized in that: The ratio of the radius of the casting roll to the number of the bypass holes is 40.9-65.

4. The casting roll according to any one of claims 1 to 3, characterized in that: The ratio of the radius of the casting roll to the radius of the center hole is 15.6 to 16.

5.

5. The casting roll according to claim 4, characterized in that: The distance between the central axis of the bypass hole and the outer peripheral surface of the casting roller is L, and the ratio of the radius of the casting roller to the L is 5.5-6.

6. The casting roll according to any one of claims 1 to 3, characterized in that: The diameter of the casting roll is 500 mm to 1500 mm.

7. The casting roll according to any one of claims 1 to 3, characterized in that: The diameter of the casting roll is 500 mm, the radius of the bypass hole is 13 mm, the radius of the center hole is 15 mm, and the number of the bypass holes is 6.

8. The casting roll according to claim 7, characterized in that: The distance between the central axis of the bypass hole and the outer peripheral surface of the casting roll is 45 mm.

9. A method for using the casting roll according to any one of claims 1 to 8, characterized in that: When the casting roller performs a single pass of ≥10mm reduction on the continuous casting slab, cooling water is introduced into the center hole and the bypass hole, wherein the cooling water in the center hole and the bypass hole flows in the same direction, the cooling water flow rate in the center hole is 50L / min~300L / min, and the total cooling water flow rate in the bypass hole is 200L / min~1000L / min.

10. The method for using a casting roll according to claim 9, characterized in that: The cooling water flow rates in the plurality of bypass holes are the same.

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