JP2006095545A - Apparatus and method for cooling metallic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for cooling a metallic material which can uniformly cool the metallic material without exchanging a spray device, even in the case of changing the shape or the size of a material to be cooled, and a method for cooling the metallic material, using this cooling apparatus. <P>SOLUTION: The cooling apparatus 5 for metallic material is provided with a header 2 having gas-liquid mixed spray nozzles 1, 1,... and the gas and the liquid supplied into the header 2, are individually supplied into the gas-liquid mixed spray nozzles 1, 1,... through the individual space in the header 2, and the header 2 is formed as a cylindrical shape and also, the gas-liquid mixed spray nozzles 1, 1,... are disposed at the inner peripheral surface 6 side of the header 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal material cooling device and a metal material cooling method, and in particular, a high-temperature steel piece such as a billet, bloom, or section steel having a cross-sectional shape such as square, round, H-shaped, or I-shaped. The present invention relates to a metal material cooling apparatus capable of uniformly and rapidly cooling a high-temperature steel material, and a metal material cooling method using the cooling apparatus.

  In the continuous casting process of the steel making process, the melted steel after component adjustment is continuously hardened into a thick steel piece, and intermediate materials such as billets and blooms are produced according to the shape of the steel material. The billet and bloom are first cooled in the mold to be in a semi-solid state, and then secondarily cooled in the drawing passage of the billet and bloom immediately below the mold. In secondary cooling of billets and blooms, spray cooling is usually performed by water jet, and cooling water is sprayed from the spray nozzle onto the surface of the billet or bloom so that it is gradually cooled while passing through the drawing passage. The billet and bloom solidified.

  Conventionally, in the secondary cooling, water is sprayed from the four directions onto the billet or bloom surface, and a cooling device used in the secondary cooling (hereinafter sometimes referred to as a “spray device”). It was a dedicated device for billets and blooms of each size. Therefore, every time the size of the billet or bloom changes, it is necessary to hang the mold off-line once and replace the spray device, and this work at the time of replacement has been one of the causes of lowering the productivity of the steelmaking process.

  On the other hand, the billet or bloom has a square or rectangular cross-section, and the billet or bloom is likely to be uneven in temperature only by cooling from four directions. Here, when temperature irregularity occurs in the billet or bloom, warpage or bending is likely to occur due to the thermal stress. Further, if the strain caused by temperature unevenness remains in the billet or bloom, there is a tendency that the strain is released and the product is deformed when cut into a product. Therefore, in order to improve the quality of the steel material, it is important to cool the billet and bloom uniformly.

So far, several techniques relating to secondary cooling of billets and blooms and techniques applicable to the secondary cooling have been disclosed. As a technique related to secondary cooling of a billet, for example, Patent Document 1 discloses a technique related to a spray cooling method and a spray cooling apparatus that can cool a billet without changing the spray apparatus even when the billet size is changed. Yes. According to the technique disclosed in Patent Document 1, the distance between the billet surface and each spray nozzle facing the billet surface can be changed equally to enable cooling without replacing the spray device. It is going to be. Further, the technique disclosed in Patent Document 1 is also applicable to a form in which a spray nozzle is provided in an annular or octagonal supply pipe, and a form in which water is jetted from multiple directions is also possible. Has been taken into account. On the other hand, as a technique applicable to the secondary cooling described above, for example, Patent Document 2 discloses a technique related to a gas-liquid spray apparatus including a mixing adapter for causing liquid and air to collide and mix with each other.
JP 2000-312954 A JP 7-164121 A

  However, since the spray nozzle used in the technique disclosed in Patent Document 1 has a large size, the nozzle arrangement density (hereinafter simply referred to as “nozzle density”) may be sufficiently increased. Have difficulty. Therefore, even if water is sprayed from multiple directions by the spray cooling method and the spray cooling device having the above-described configuration, it is difficult to cool the billet uniformly, and there is a problem that temperature unevenness is likely to occur in the billet. Further, even in the technique disclosed in Patent Document 2, since a large-sized nozzle is used, even if the gas-liquid spraying device having the nozzle is applied to the secondary cooling, the billet and the bloom are uniformly cooled. There was a problem that it was difficult to do.

  Therefore, in the present invention, a metal material cooling device capable of uniformly cooling the metal material without changing the spray device even when the shape or size of the material to be cooled is changed, and a metal material using the cooling device. It is an object to provide a cooling method.

As a result of earnest research on the technology capable of uniformly cooling the material to be cooled without replacing the device regardless of the shape and size of the material to be cooled, the present inventors have obtained the following knowledge.
1) Even when the shape and size of the material to be cooled are changed by changing the gas-liquid ratio of the gas-liquid mixture ejected from the nozzle using the cooling device including the gas-liquid mixing spray nozzle, It becomes possible to cool the material to be cooled without replacing the cooling device.
2) In the gas-liquid mixing spray nozzle, if a gas-liquid mixing spray nozzle of a type in which gas and liquid are separately supplied is used, the nozzle can be miniaturized. Therefore, it is possible to sufficiently increase the nozzle density in the cooling device, and to cool the material to be cooled uniformly.

  The present invention has been made based on such knowledge. The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

1st this invention is provided with the header (2) provided with a gas-liquid mixing spray nozzle (1, 1, ...), and the gas and liquid supplied to a header (2) are in the said header (2). It is supplied individually to the gas-liquid mixing spray nozzles (1, 1,...) Via the individual spaces (20, 21), and the header (2) is cylindrical, and the gas-liquid mixing spray nozzle (1, 1,...) Are arranged on the inner peripheral surface (6) side of the header (2), and the above problem is solved by the metal material cooling device (5).
Here, the “cylindrical shape” means a shape that can surround the side surface of the material to be cooled (3) conveyed inside the header (2), and the cross-sectional shape thereof is not particularly limited. Examples of the cross-sectional shape of the cylindrical header (2) according to the present invention include a triangle, a rectangle, a circle, and an ellipse.
Moreover, in the said 1st this invention, the cooling device (5) of a metal material is a gas-liquid ratio of the gas-liquid mixture (8, 8, ...) injected from a gas-liquid mixing spray nozzle (1, 1, ...). It is preferable to provide a gas-liquid ratio control means for controlling the above. Here, in the present invention and the invention shown below, the gas-liquid ratio means the ratio of the gas flow rate and the liquid flow rate injected from one nozzle (1), and the gas injected from the nozzle (1). The gas-liquid ratio R is given by the following equation, where Q _g (L / min) and the liquid flow rate are Q _w (L / min).
R = _Qg / _Qw

  Furthermore, in the first aspect of the present invention, it is preferable that the header (2) can be divided into at least two or more.

  In addition, in the first aspect of the present invention, it is preferable that a gap (7, 7,...) Is provided in at least a part of the header (2, 2).

  The second aspect of the present invention is a method of cooling a metal material using the metal material cooling device (5) according to the first aspect of the present invention, and is injected from a gas-liquid mixing spray nozzle (1, 1,...). The above-mentioned problems are solved by a method for cooling a metal material, wherein the gas-liquid ratio of the gas-liquid mixture (8, 8,...) Is 3 or more.

  In the second aspect of the present invention, it is preferable that the gas-liquid ratio of the gas-liquid mixture (8, 8,...) Is set in accordance with the shape, conveying speed, and material of the material to be cooled (3).

According to 1st this invention, the gas and liquid supplied to the space (20, 21) divided | segmented separately in the cylindrical header (2) are gas-liquid mixing spray nozzles (1, 1, ...). ), And the gas-liquid mixture (8, 8,...) Mixed in the spray nozzle (1, 1,...) Is injected from the spray nozzle (1, 1,...) It can be a material cooling device (5). With this configuration, the nozzles (1, 1,...) Can be downsized, and the interval between the nozzles (1, 1,...) Provided in the cooling device (5) can be shortened. As a result, the nozzle density can be made sufficiently high. Therefore, according to 1st this invention, it becomes possible to provide the cooling device (5) of a metal material which can cool the whole side surface of a to-be-cooled material (3) uniformly. According to the metal material cooling device (5) according to the first aspect of the present invention, the nozzle density can be sufficiently increased. Therefore, if the cooling device (5) is used, the material to be cooled (3 ) Can be rapidly cooled.
Further, in the first aspect of the present invention, gas-liquid ratio control means for controlling the gas-liquid ratio of the gas-liquid mixture (8, 8,...) Ejected from the gas-liquid mixing spray nozzle (1, 1,. If provided, it is easy to change the cooling capacity of the cooling device (5), and the cooling device (5) can cool a material to be cooled of various shapes and sizes without replacing the device. Becomes easier. Therefore, with this configuration, it is easy to provide a metal material cooling device (5) that can cool the material to be cooled uniformly without replacing the device regardless of the shape and size of the material to be cooled. become. That is, according to the first aspect of the present invention, since it is possible to eliminate the need for device replacement, it is possible to reduce the time, cost, etc. required for device replacement. It is also possible to provide a metal material cooling device (5) capable of improving the property.

  Furthermore, in the first aspect of the present invention, if the header (2) can be divided into at least two or more, for example, the material to be cooled (3) is stuck in the cooling device (5). However, by dividing the cylindrical header (2), it is possible to recover the bump without moving the entire cooling device (5), so that the maintainability is improved. Therefore, by providing such a configuration, it is possible to provide a cooling device (5) for a metal material that can cool the material to be cooled (3) uniformly and can further improve the productivity. Is possible.

  In addition, in the first aspect of the present invention, if a gap (7, 7,...) Is provided in at least a part of the header (2, 2), the inner peripheral surface (6) of the cylindrical header (2). ) Side liquid can be discharged from the gap (7, 7,...). Therefore, with this configuration, it is possible to provide the metal material cooling device (5) that can further improve the liquid discharge performance.

  According to the second aspect of the present invention, by setting the gas-liquid ratio of the gas-liquid mixture (8, 8,...) To 3 or more, it becomes possible to easily reduce the temperature unevenness of the material to be cooled (3). . Moreover, it becomes possible to change the cooling capacity of a cooling device (5) suitably by changing the gas-liquid ratio of a gas-liquid mixture (8, 8, ...). Therefore, according to the second aspect of the present invention, it is possible to provide a metal material cooling method capable of uniformly cooling a material to be cooled without replacing the device regardless of the shape and size of the material to be cooled. .

  In the second aspect of the present invention, if the gas-liquid ratio of the gas-liquid mixture (8, 8,...) Is set in accordance with the shape, transport speed, and material of the material to be cooled (3), It becomes possible to provide a metal material cooling method capable of appropriately controlling the cooling capacity according to the shape and size, and it becomes easy to uniformly cool the materials to be cooled having various shapes and sizes.

Hereinafter, embodiments of the present invention will be described.
First, in order to facilitate understanding of the present invention, differences between the conventional cooling device and the cooling device of the present invention will be outlined with reference to the drawings. FIG. 1 is an external view showing a part of a cooling device of the present invention and a conventional cooling device. FIG. 1A schematically shows a part of the cooling device of the present invention according to the first embodiment, and FIG. 1B schematically shows a part of the conventional cooling device. In the following description, a case where water is used as a cooling medium will be described. Hereinafter, the “gas / liquid ratio” may be referred to as “gas / water ratio”.

  As shown in FIG. 1 (a), the cooling device 5 according to the first embodiment of the present invention includes a gas-liquid mixing spray nozzle (hereinafter sometimes simply referred to as “nozzle”) 1, 1,. It has. The nozzles 1, 1,... Are arranged on the inner peripheral surface 6 side of the semicylindrical headers 2, 2, and the two headers 2, 2 form a cylindrical header. The rod-shaped material 3 to be cooled passing through the inside of the headers 2, 2 divided into upper and lower parts is arranged on a line (not shown), and is conveyed in the direction from the back to the front of the figure. It is cooled by the gas-liquid mixture 8, 8,... Ejected from 1, 1,. Here, in the cooling device 5 according to the present invention, gas (hereinafter referred to as “air”) and water are supplied to the headers 2 and 2 via separate pipes 4 a and 4 b, respectively. The air and water individually supplied to 2 and 2 are supplied to separate spaces provided in the headers 2 and 2, respectively. On the other hand, the nozzles 1, 1,... Provided in the cooling device 5 are provided with an outlet-side flow path for injecting the gas-liquid mixture 8, 8,. The air and water supplied to the nozzles 1 are supplied to the nozzles 1, 1,... Via separate flow paths provided in the nozzles 1, 1,. And the said air and water become the gas-liquid mixture 8, 8, ... in the said nozzle 1,1, ..., and are injected toward the to-be-cooled material 3 from the exit side flow path of the nozzle 1,1, .... . The headers 2, 2 according to the present invention are provided with a plurality of gaps 7, 7..., And the water accumulated on the inner peripheral surfaces 6, 6 side of the headers 2, 2 is the gaps 7, 7. ,... Are discharged to the outside of the headers 2 and 2. Further, the upper and lower headers 2 and 2 shown in FIG. 1A are fixed via a plurality of screws 9, 9. In addition, the cooling device 5 according to the first embodiment has a configuration in which the gas-liquid ratio of the gas-liquid mixture ejected from the nozzles 1, 1,. ing. For the sake of convenience, FIG. 1A shows only the nozzles 1, 1,... And the gaps 7, 7,. While being arranged in a staggered manner at intervals, the gaps 7, 7,... Are formed in the traveling direction of the material to be cooled 3 (direction from the back to the front in FIG. 1), for example, in the form of a groove. Shall.

On the other hand, as shown in FIG. 1B, the conventional cooling device 55 includes gas-liquid mixing spray nozzles (hereinafter sometimes simply referred to as “nozzles”) 51, 51,. A plurality of ring-shaped headers 52, 52,. As shown in FIG. 1B, in the conventional cooling device 55, nozzles 51, 51,... Are usually provided at four locations of headers 52, 52,. The material 53 to be cooled is cooled by the gas-liquid mixture. .. And the nozzles 51, 51,... In FIG. 1B through the gas supply pipes 54a, 54a,... And the liquid supply pipes 54b, 54b,. Is supplied. Moreover, the to-be-cooled material 53 in FIG.1 (b) shall be arrange | positioned on the line which is not shown in figure.
FIG. 7 schematically shows the conventional nozzle 51 in an enlarged manner. As shown in FIG. 7, the air supplied to the inside of the conventional nozzle 51 and the water atomized by colliding with the mixing promoting means 51b are mixed in a mixing chamber 51c to form a gas-liquid mixture. The mixture is sprayed from the nozzle tip 51a toward the material to be cooled. The nozzle 51 according to FIG. 1B is a simplified illustration of the nozzle 51 according to FIG.

  Also by the conventional cooling device 55 shown in FIG. 1B, the number of nozzles 51, 51,... Provided in each header 52, 52,. It is also possible that the cooling that is obtained is possible. However, the nozzles 51, 51,... Provided in the conventional cooling device 55 have a size of, for example, “fist size”, and the density of the nozzles 51, 51,. Since it is difficult to sufficiently increase the number of nozzles 51, 51,... That can be provided in each header 52, 52,..., There is a problem that it is difficult to reduce temperature unevenness of the material 53 to be cooled.

  Here, FIG. 2 and FIG. 3 schematically show examples of the nozzle 1 and the header 2 that can be provided in the cooling device 5 of the present invention. 2 and 3, the vertical direction is a vertical direction.

  FIG. 2 is a cross-sectional view schematically showing an example of the form of the nozzle 1, FIG. 2A is a cross-sectional view of the nozzle 1 including the mixing unit 13 having a certain space, and FIG. Sectional drawing of the nozzle 1 provided with the mixing part 13 which is a confluence | merging part, FIG.2 (c) is a figure which shows the vertical direction cross section which does not contain a subchannel.

  The nozzle 1 according to the present invention is a chip-like nozzle (hereinafter simply referred to as “nozzle”) 1 used in the above-described cooling device 5 according to the present invention. The mixing section 13 and the outlet-side flow path 12 are arranged in this order and lead to the main flow path 18 passing through the nozzle 1 and the side face 19 of the nozzle to the mixing section 13 and the flow direction is 30 to 60 with respect to the main flow path 18. .., And the inlet side channel 11 has an inlet side opening smaller than the mixing unit side opening, and the channel side surface 15 is inclined with respect to the flow direction. The angle is 5 to 25 degrees.

  On the other hand, FIG. 3 is a diagram schematically showing a part of a vertical cross section of the header 2 including the nozzle 1, and an enlarged cross section showing only the portion of the header 2 where the nozzle 1 is installed and its periphery. FIG.

  The header 2 according to the present invention includes the nozzle 1 and includes a first fluid supply unit 20 that communicates with the inlet-side opening of the inlet-side channel 11 and a second fluid supply that communicates with the nozzle-side side openings of the sub-channels 14 and 14. The nozzle 21 includes a first partition 30 and a second partition, and a first partition 30 that partitions the fluid supply unit, a second partition 31 that partitions the second fluid supply unit 21 and the ejection surface side. In addition to being fixed to 31, the outlet-side flow path 12 opens to the ejection surface side of the second partition wall 31. In the header 2 according to the present invention, for example, air is supplied into the first fluid supply unit 20 and water is supplied into the second fluid supply unit 21. Air in the first fluid supply unit 20 is supplied into the nozzle 1 through the inlet-side flow path 11, and water in the second fluid supply unit 21 passes through the sub-flow paths 14, 14 to the nozzle. After being supplied into 1 and mixed in the mixing section 13 of the nozzle 1, the gas-liquid mixture passes through the outlet side flow path 12 and is jetted downward from the outlet side opening in FIG. 3.

As shown in FIGS. 2 and 3, the nozzle 1 provided in the cooling device 5 of the present invention has a structure in which air and water are individually supplied through a plurality of flow paths provided in the nozzle 1. have. Therefore, it is possible to make the nozzles 1, 1,... Smaller than the conventional one (for example, about 1/3 size), and in the header 2 including the nozzles 1, the nozzle density can be sufficiently increased. It becomes possible. Therefore, in the cooling device 5 according to the present invention including the header 2, the material to be cooled 3 can be uniformly cooled, so that the temperature unevenness of the material to be cooled 3 can be reduced. Furthermore, since the cooling device 5 according to the present invention includes gas-liquid mixing spray nozzles 1, 1,... Having high cooling ability among various nozzles, it is possible to easily reduce temperature unevenness of the material 3 to be cooled. At the same time, the material 3 to be cooled can be rapidly cooled. In the present invention, the nozzle density of the nozzles 1, 1,... Provided in the cooling device 5 is not particularly limited as long as it is a density that can cool the material to be cooled 3 uniformly. / M ² or more, and the arrangement of the nozzles 1, 1,... Arranged at such a density is preferably staggered.

  Further, in the cooling device 5 of the present invention, it is preferable to appropriately change the gas-liquid ratio of the gas-liquid mixture ejected from the nozzles 1, 1,... According to the shape and size of the material to be cooled. By changing the gas-liquid ratio, the cooling capacity of the cooling device 5 can be changed, so that the cooling material can be uniformly cooled without replacing the device regardless of the shape and size of the cooling material. It becomes easy to obtain the metal material cooling device 5 to be obtained.

Here, the gas-liquid ratio means the ratio of the gas flow rate injected from one nozzle to the liquid flow rate, the flow rate of air injected from the nozzle 1 is Q _g (L / min), and the flow rate of water. Is Q _w (L / min), the gas-liquid ratio (gas-water ratio) R is given by the following equation.
R = _Qg / _Qw

  As described above, the cooling device 5 according to the present invention can arrange the gas-liquid mixing spray nozzles 1 having high cooling ability at high density. Therefore, as will be described later, for example, if the gas-liquid ratio is set to 3 in the present invention, it becomes possible to reach the cooling capacity when the gas-liquid ratio is set to 40 in the conventional cooling device, and the material to be cooled 3 It is possible to easily reduce the temperature unevenness. Therefore, when the metal material is cooled using the cooling device 5 according to the present invention, the gas-liquid ratio of the gas-liquid mixture ejected from the nozzle 1 is set to 3 or more. Generally, it is said that if the gas-liquid ratio is increased, the cooling ability can be increased. However, if the gas-liquid ratio is increased, the running cost of the cooling device 5 increases. Therefore, a more preferable gas-liquid ratio is 5 or more and 10 or less from the viewpoint of securing sufficient cooling ability while reducing running cost.

  When the metal material is cooled using the cooling device 5 according to the present invention, the gas-liquid ratio of the gas-liquid mixture ejected from the device 5 is appropriately set according to the shape, the conveying speed, and the material of the material 3 to be cooled. To do. By doing in this way, it becomes possible to cool the to-be-cooled material 3 uniformly, suppressing the waste of air and water. Below, the example of setting the gas-liquid ratio according to the shape of the to-be-cooled material 3, a conveyance speed, and a material is demonstrated.

<Setting according to shape>
When the distance between the material to be cooled and the nozzle (hereinafter referred to as “cooling surface distance”) is increased, the collision speed of the gas-liquid mixture decreases, so that the material to be cooled becomes difficult to be cooled. Since the collision speed of the gas-liquid mixture increases, the material to be cooled is easily cooled. Therefore, for example, when the cross-sections of two different materials to be cooled are similar, the gas-liquid ratio is reduced as the cross-sectional area increases. By doing in this way, it becomes possible to keep the cooling capacity with respect to a to-be-cooled material constant irrespective of the size of the to-be-cooled material 3. In addition, when the cross-sections of two different materials to be cooled are similar, the heat capacity of the material to be cooled increases as the cross-sectional area increases. By increasing the gas-liquid ratio as the area increases, the cooling stop temperature of the material to be cooled can be kept constant. Further, for example, when the material to be cooled is H-shaped steel or I-shaped steel, the cooling surface distance is likely to vary depending on the portion of the material to be cooled even in the same material to be cooled. Therefore, when cooling such a material to be cooled, the gas-liquid ratio of the gas-liquid mixture ejected from the nozzle having the short cooling surface distance is reduced, while the gas-liquid mixture of the gas-liquid mixture ejected from the nozzle having the far distance is used. It is preferable to increase the ratio. By controlling in this way, each surface to be cooled can be uniformly cooled.

<Setting according to transport speed>
When the conveyance speed of the material to be cooled increases, the time for which the material to be cooled stays in the cooling device according to the present invention is shortened, so that the material to be cooled becomes difficult to be cooled. Therefore, the material to be cooled is easily cooled. Therefore, in the present invention, it is preferable to increase the gas / liquid ratio when the conveyance speed of the material 3 to be cooled is high, and to decrease the gas / liquid ratio when the conveyance speed is low.

<Setting according to material>
For example, when a steel material containing a large amount of Mn or Si is cooled, a scale that is thick and difficult to peel is easily formed on the surface of the steel material. Here, it is known that such a scale has an effect of promoting cooling of the steel material. Therefore, when cooling the steel material, it is preferable to reduce the gas-liquid ratio. In addition, when cooling a material to be cooled that is easy to cool, the gas-liquid ratio is reduced, and when cooling a material that is difficult to cool, the gas-liquid ratio is increased to increase other conditions (conveying speed, If the shape, cooling time, etc.) are the same, the temperature of the material to be cooled cooled by the cooling device according to the present invention can be made constant.

  For convenience, in the above description, the form in which the gas-liquid mixture of air and water is jetted is described. However, the gas and liquid supplied to the header and the nozzle according to the present invention are not limited to air and water. Absent. In the present invention, any gas and liquid that can sufficiently cool the material to be cooled, have a small load on the environment, and can reduce running costs can be preferably used.

  Moreover, in the said description, as shown in FIG. 1, although the cooling device which has a cylindrical header was described, the cross-sectional shape of the header concerning this invention is not limited to a circle. As a specific example of another cross-sectional shape provided in the cylindrical header according to the present invention, a rectangle or the like can be given as shown in FIG. Here, FIG. 4 differs only in the shapes of the header and the material to be cooled, and the function of the cooling device 15 shown in FIG. 4 is not different from the cooling device shown in FIG. Therefore, in FIG. 4, the same reference numerals as those in FIG.

  The metal material that can be cooled by the metal material cooling device and the cooling method according to the present invention is not particularly limited, and the shape thereof is not particularly limited. Specific examples of the metal material that can be cooled by the metal material cooling device and the cooling method according to the present invention include a square, a circle, a billet, a bloom having a cross-sectional shape such as an H shape, an I shape, or a shape steel. Steel materials can be mentioned. Here, for example, when a steel material is cooled, if a part of the steel is supercooled by a cooling device, the surface structure of the supercooled part undergoes martensitic transformation, and the mechanical test strength and yield strength are very large. Thus, cracks and shape defects are likely to occur during rolling. Such inconvenience can be reduced by keeping the temperature unevenness of the material to be cooled at 15 ° C. or less. Therefore, in the present invention, when the steel material is cooled, it is preferable to set the above various conditions so that the temperature unevenness of the material to be cooled falls within 15 ° C. or less.

  The cooling device and the cooling method according to the present invention will be described more specifically with reference to examples. In addition, about the nozzle with which the cooling device concerning this invention is equipped, the code | symbol used in FIG. 2 is attached | subjected suitably and demonstrated.

1. Test conditions In the nozzle 1 provided in the cooling device (example) according to the present invention, the diameter of the inlet channel 11 is 1 to 1.6 mm, the diameter of the auxiliary channel 14 is 3 to 6 mm, and the outlet channel 12 The diameter was 3 to 12 mm, and the vertical length of the nozzle 1 was 20 mm. In contrast, the nozzle provided in the conventional cooling device (comparative example) has a gas inlet hole diameter of 6 mm, a liquid inlet hole diameter of 5.5 mm, and an outlet hole diameter of 6 to 7 mm. The vertical length of the nozzle was 120 mm. In addition, the inlet hole for the gas of the nozzle concerning a comparative example is the entrance side flow path 11 concerning an Example, the inlet hole of the particle | grain aspect of the nozzle concerning a comparative example is the subflow path 14 concerning an Example, and a comparative example. Such outlet holes respectively correspond to the outlet flow paths 12 according to the embodiment.
Although the nozzle according to the comparative example has a tip that is as thin as the tip of the nozzle according to the embodiment, a mixing chamber for mixing air and water is provided at the base (the main body header side) of the nozzle according to the comparative example. It was provided. Therefore, the size of the entire nozzle is about 5 to 6 times that of the nozzle according to the comparative example, and the maximum number of nozzles that can be provided in one header according to this comparative example is 4 It was a piece.

  Table 1 shows the test conditions in this example and this comparative example.

  Here, in Table 1, the nozzle interval in the circumferential direction means the interval between nozzles provided in the circumferential direction of the header having a substantially circular cross-sectional shape, and in the case of 45 degrees (example), it is cylindrical. Eight nozzles are arranged on the same circumference of the header, and the case of 90 degrees (comparative example) means that four nozzles are arranged on the same circumference of the ring-shaped header. The nozzle spacing in the traveling direction means the spacing between nozzles provided in the traveling direction of the material to be cooled. Furthermore, the nozzle flow rate means the flow rate of the gas-liquid mixture ejected from the nozzle. In addition, the cooling zone length means the length in which the nozzle and the header according to the present invention are arranged in the traveling direction of the material to be cooled. As shown in Table 1, the air / water ratio was changed in the range of 3 to 15 in the present example, whereas the air / water ratio was changed in the range of 15 to 40 in the present comparative example.

2. Test results Based on the above test conditions, a 120 mm diameter steel bar was cooled from 800 ° C to 500 ° C. The relationship between the cooling capacity ratio and the air / water ratio during the cooling is shown in FIG. In FIG. 5, the solid line and the broken line indicate the results of the example and the comparative example, respectively. FIG. 5 shows the cooling capacity when the air / water ratio is set to 15 in the cooling device according to the present embodiment as 1 (reference), and other air / water ratios (3, 5, 7, 10) in this embodiment. In this comparative example, the cooling capacity and the degree of cooling capacity in each comparative example (15, 20, 25, 30, 40) are calculated, and the calculation results are shown. In this embodiment, if the air / water ratio is greater than 15, the cooling capacity itself is considered to be higher than when the air / water ratio is 15, but the running cost also increases. Therefore, for convenience, the air-to-water ratio according to the present embodiment is set to 15 as an upper limit.

  As shown in FIG. 5, when the air-to-water ratio is increased and the air flow rate is increased, the flow rate of the liquid droplets that collide with the steel bar that is the material to be cooled increases, so that the cooling capacity increases. However, if the air flow rate exceeds a certain amount (the air / water ratio 40 in the comparative example), the droplet diameter becomes too small and the effect of increasing the droplet flow velocity reaches its peak, resulting in momentum penetrating the vapor film. It cannot be obtained, and the cooling capacity is slightly reduced. Therefore, the cooling capacity ratio of the cooling device according to this comparative example stayed at 0.7 or less at the maximum. On the other hand, in the cooling device according to the present example, even when the air / water ratio was set to 3, a cooling capacity ratio of 0.9 or more could be secured. Therefore, from the results of this example and this comparative example, it was confirmed that the cooling device according to the present invention has a higher cooling capacity than the conventional cooling device by setting the air / water ratio to 3 or more.

FIG. 6 shows the result of investigating the temperature unevenness of the steel bar when the steel bar is cooled under the same test conditions as when the result shown in FIG. 5 was obtained. In FIG. 6, the solid line and the broken line show the results of the example and the comparative example, respectively. The temperature unevenness in FIG. 6 was calculated using a one-dimensional heat conduction equation.
As shown in FIG. 6, in the cooling device according to this example, the temperature unevenness could be suppressed to 15 ° C. or less by setting the air / water ratio to 3 or more. On the other hand, in the cooling device according to the comparative example, if the air / water ratio was set to 40, the temperature unevenness could be about 15 ° C., but if the air / water ratio was set to 30 or less, the temperature unevenness was 15 ° C. When the air / water ratio was set to 15 in the cooling device according to the comparative example, the temperature unevenness was 40 ° C. Therefore, if the air / water ratio is set to 3 or more in the cooling device according to the present embodiment, it is possible to suppress the temperature unevenness of the steel bar to 15 ° C. or less. It was confirmed that it could be cooled.

It is an external view which shows roughly a part of cooling device of the present invention concerning the 1st embodiment, and the conventional cooling device. It is sectional drawing which shows the example of a form of a nozzle roughly. It is sectional drawing which shows the example of a form of a header and a nozzle roughly. It is an external view which shows roughly the example of the form of the header with which the cooling device of this invention is equipped. It is a figure which shows the relationship between an air-water ratio and a cooling capacity ratio. It is a figure which shows the relationship between an air-water ratio and temperature nonuniformity. It is an external view which shows the conventional nozzle schematically.

Explanation of symbols

1, 51 Nozzle 2, 52 Header 3, 53 Material to be cooled (metal material)
4a Air supply pipe 4b Water supply pipe 5, 15, 55 Cooling device 6 Inner peripheral surface 7 Gap 20 First fluid (air) supply part 21 Second fluid (water) supply part

Claims (5)

A header with a gas-liquid mixing spray nozzle,
The gas and liquid supplied to the header are individually supplied to the gas-liquid mixing spray nozzle through individual spaces in the header,
The metal material cooling device, wherein the header is cylindrical and the gas-liquid mixing spray nozzle is disposed on an inner peripheral surface side of the header. The metal material cooling device according to claim 1, wherein the header can be divided into at least two or more. The metal material cooling device according to claim 1, wherein a gap is provided in at least a part of the header. A metal material cooling method using the metal material cooling device according to any one of claims 1 to 3,
The method for cooling a metal material, wherein a gas-liquid ratio of a gas-liquid mixture ejected from the gas-liquid mixing spray nozzle is 3 or more. The method for cooling a metal material according to claim 4, wherein a gas-liquid ratio of the gas-liquid mixture is set in accordance with a shape, a conveying speed, and a material of a material to be cooled.

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