KR20240021278A - Quenching device, quenching method, manufacturing method of cold rolled steel sheet, and manufacturing method of plated steel sheet - Google Patents

Abstract

In addition to being excellent at cooling the metal plate, it is easy to switch between quenching and non-quenching conditions, and can suppress thermal deformation due to heat radiation from the metal plate. Provides a device. The cooling device 11 includes a tank 5 containing a cooling medium 2 in which the metal plate 1 is immersed, and a metal plate 1 running through the tank 5 within the tank 5. At least one pair of rolls 4 (roll 4a, roll ( 4b)) is provided.

Description

Quenching device, quenching method, manufacturing method of cold rolled steel sheet, and manufacturing method of plated steel sheet

The present invention relates to a quenching device, a quenching method, a method of manufacturing a cold rolled steel sheet, and a method of manufacturing a plated steel sheet, and more specifically, to a continuous annealing facility that performs annealing while continuously sheeting a metal sheet. In order to expand the degree of freedom of conditions, it relates to a quenching device that facilitates switching between conditions that perform quenching and conditions that do not quench.

In the production of metal plates (metal plate products) including steel plates, in a continuous annealing facility where annealing is performed while continuously sheeting a metal plate, the material is adjusted by heating and then cooling the metal plate to cause a phase transformation.

Recently, in the automobile industry, demand for thinner high-strength steel sheets (HI-TEN) has been increasing for the purpose of reducing the weight of the car body and achieving both crash safety. When manufacturing high-strength steel sheets, technology for rapidly cooling the steel sheets becomes important. As one of the technologies with the fastest cooling rate of steel sheets, the water cooling method is known. In the water quenching method, in order to efficiently and stably quench the water, a heated steel sheet is immersed in water and cooling water is sprayed onto the steel sheet through a quench nozzle formed in the water to remove the vapor film that forms on the surface of the steel sheet. It was necessary to do it. On the other hand, there is also a demand for steel sheets that do not require water quenching. In order to efficiently manufacture both, the presence or absence of water quenching can be switched in one manufacturing facility, and the steel sheets that require water quenching and the steel sheets that require water quenching can be combined with water. It is necessary to manufacture both sides of a steel plate that does not require quenching in one manufacturing facility.

For example, in Patent Document 1, in immersion water for cooling a heated strip, cooling water spray nozzles are formed in multiple stages, and the headers of each nozzle are individually independent and arranged to be spaced apart with respect to the strip travel direction, so that each By creating a gap between the nozzle headers and allowing the jet of coolant that has hit the cooled surface of the strip to flow out to the rear of the header through the gap between the headers, the lateral flow that occurred in the conventional multi-slit nozzle is prevented, and the flow in the sheet width direction is prevented. A cooling device that provides uniformity in cooling has been proposed.

Japanese Patent Publication No. 59-153843 Japanese Patent Publication No. 2013-185182

However, in the cooling device described in Patent Document 1, when switching from a condition in which water is cooled using a coolant spray nozzle in immersion water to a condition in which immersion water is not used, the coolant spray nozzle is exposed to heat radiation from the heated strip or atmosphere. Because it is thermally deformed, a very time-consuming operation of opening the furnace and removing the cooling water spray nozzle from the device is required, which has the problem of significantly impeding productivity.

Therefore, in Patent Document 2, a reflector made of a metal plate or heat insulating material is formed between the water jet nozzle and the steel strip to suppress radiation and heat conduction from the steel strip, and the steel strip is not cooled by the water jet nozzle to achieve high temperature. When changing from the condition to the quenching condition in which the steel strip is cooled by a water injection nozzle, cooling gas is supplied from the cooling gas supply unit to the water injection nozzle, and in removing moisture from the steel strip after quenching, the steel strip is cooled. A method has been proposed in which moisture is removed by spraying gas while pushing a pair of pressure rolls installed at a distance from each other in the longitudinal direction and bringing a pair of slit nozzles close to the steel strip.

However, even in the method described in Patent Document 2, there is a problem that the reflector becomes hot and undergoes thermal deformation.

The present invention was made to solve such problems. For example, when performing quenching by immersing a heated metal plate in a cooling medium in a continuous annealing facility, the cooling effect of the metal plate is excellent, In addition, when quenching by immersion in a cooling medium is not performed, it is possible to prevent thermal deformation of the device, and it is easy to switch between conditions for quenching and conditions for not performing quenching. The purpose is to provide a quenching device.

As a result of repeated studies to solve this problem, the present inventors obtained the following knowledge and idea.

That is, in the conventional cooling of a metal plate (for example, a steel plate), uniform rapid cooling is performed by removing the vapor film generated on the surface of the metal plate by the impact pressure of water sprayed from a water spray nozzle. If the condition is changed to not using the water spray nozzle, the water spray nozzle or reflector, etc. will be thermally deformed. Therefore, if the vapor film generated on the surface of the metal plate can be removed using another device that can suppress thermal deformation without using a water spray nozzle or reflector, the conditions for performing quenching and quenching can be performed. When changing the conditions to no, there is no need to open the furnace of the annealing equipment, making it possible to suppress thermal deformation of the water spray nozzle, etc.

The present invention has the following features based on the above-mentioned knowledge and idea.

[1] As a cooling device for cooling a metal plate,

a tank containing a cooling medium into which the metal plate is immersed;

In the tank, at least one pair of rolls is disposed so as to sandwich the metal plate running in the tank, the distance to the metal plate can be changed, and the roll rotates at a peripheral speed equal to or higher than the traveling speed of the metal plate. , ??qing device.

[2] The quenching device according to [1], wherein the roll rotates in a direction opposite to the traveling direction of the metal plate.

[3] The quenching device according to [1] or [2], which is installed on the exit side of the cracking furnace of the continuous annealing equipment.

[4] A quenching method of cooling a metal plate using a quenching device provided with a tank containing a cooling medium into which the metal plate is immersed,

When performing quenching by immersing a metal plate in a cooling medium,

The metal plate is driven through a tank containing a cooling medium, and at least one pair of rolls arranged in the tank so as to sandwich the metal plate running through the tank is driven at a speed equal to or higher than the running speed of the metal plate. Cooling the metal plate by rotating it at a high speed,

If quenching is not performed by immersing the metal plate in the cooling medium,

A quenching method in which the metal plate is driven through a tank that does not contain a cooling medium, and the at least one pair of rolls is arranged further away from the metal plate than in the arrangement in which the quenching is performed. .

[5] The quenching method according to [4], in which the roll is rotated in a direction opposite to the traveling direction of the metal plate.

[6] A method for manufacturing a cold-rolled steel sheet, wherein the metal sheet is a cold-rolled steel sheet, and the cold-rolled steel sheet after annealing is quenched by the quenching method described in [4] or [5].

[7] A method for manufacturing a plated steel sheet, in which a plating treatment is applied to a steel sheet obtained by the method for manufacturing a cold rolled steel sheet described in [6] above.

[8] The method for producing a plated steel sheet according to [7], wherein the plating treatment is one selected from electrogalvanizing treatment, hot-dip galvanizing treatment, and alloyed hot-dip galvanizing treatment.

According to the present invention, for example, when performing quenching by immersing a heated metal sheet in a cooling medium in a continuous annealing facility, the cooling effect of the metal sheet is excellent, and furthermore, the cooling effect of the metal sheet by immersing it in the cooling medium is excellent. When quenching is not performed, it is possible to prevent thermal deformation of the device, and it is possible to provide a quenching device that facilitates switching between quenching conditions and non-quenching conditions. .

According to the present invention, when switching between conditions for performing quenching and conditions for not performing quenching on a heated metal sheet (e.g., steel sheet) in a continuous annealing facility that performs annealing while continuously sheeting, In order to open the furnace of the continuous annealing equipment or prevent thermal deformation caused by heat radiation from the metal plate, the member placed in the tank of the quenching device is removed or the thermal deformation is prevented in the tank. Since there is no need to install a reflector for this, the conversion is easy. Therefore, both metal plates that require quenching and metal plates that do not require quenching can be manufactured with high productivity using a single quenching device. Additionally, thermal deformation caused by heat radiation from the metal plate can be suppressed.

1 is a diagram (side view) showing a quenching device according to an embodiment of the present invention, and is a diagram showing the state of the quenching device under quenching conditions.
Fig. 2 is a diagram (side view) showing a quenching device according to an embodiment of the present invention, and is a diagram showing the state of the quenching device under conditions in which quenching is not performed.
Fig. 3 is a schematic diagram showing the roll movement mechanism in the quenching device according to one embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention will be described based on the drawings. However, the present invention is not limited to the following embodiments.

1 and 2 are diagrams (side views) each showing a quenching device 11 according to an embodiment of the present invention, and FIG. 1 shows the quenching device ( 11), and FIG. 2 is a diagram showing the state of the quenching device 11 under conditions in which quenching is not performed. This quenching device 11 can be applied, for example, to a cooling facility installed on the exit side of the crack furnace of a continuous annealing device.

As shown in FIG. 1, the cooling device 11 controls the running direction of the tank 5 containing the cooling medium (liquid, water in this embodiment) 2 and the metal plate 1. It is provided with a sink roll (3) that changes and a roll (stirring roll) (4) that rotates at high speed. The rolls 4 are operated as a set of two (rolls 4a and 4b), and at least one pair is arranged in the tank 5. The roll 4 agitates and removes the vapor film generated on the surface of the metal plate 1 when the metal plate 1 is immersed in a cooling medium. That is, in the present invention, the vapor film on the metal surface, which was removed by spraying a cooling medium (water) from a nozzle in the prior art, is removed by roll agitation to obtain the same cooling effect.

As shown in FIG. 1, the rolls 4 (rolls 4a, rolls 4b) are arranged so as to sandwich the metal plate 1 running in the tank 5 (in the cooling medium 2). And, specifically, in the tank 5, they are arranged at opposing positions with the metal plate 1 in between. In the quenching device 11 shown in FIG. 1, six pairs of rolls are arranged at predetermined intervals from above to below the tank 5 along the running direction of the metal plate 1. In addition, in FIG. 1, the arrows given to the rolls 4 (rolls 4a and 4b) indicate the rotation direction of the rolls 4. In addition, the arrow given along the metal plate 1 indicates the running direction of the metal plate 1.

In Figure 1 (conditions for performing quenching), the rolls 4 (rolls 4a and 4b) remove the vapor film generated on the surface of the metal plate 1 when the metal plate 1 is rapidly cooled. It is placed in a position where the action is obtained. Here, rapid cooling refers to a process in which the metal plate 1, which has been heated by annealing or the like, is cooled by immersing it in a cooling medium (liquid, water in this embodiment). Specifically, when the roll 4a and the roll 4b are viewed from the side of the quenching device 11, the outer periphery of the roll is each 50 degrees from the metal plate 1 from the position in contact with the metal plate 1. It is placed at a distance of less than mm. Preferably, the most remarkable effect is obtained by arranging the rolls 4 (rolls 4a, rolls 4b) at a position where the outer periphery of the roll is in contact with the metal plate 1.

When performing quenching, the rolls 4 (rolls 4a, rolls 4b) rotate at a peripheral speed equal to or higher than the traveling speed of the metal plate. More specifically, the peripheral speed of the roll 4 is preferably 1.0 times or more relative to the running speed of the metal plate 1. If the peripheral speed of the roll 4 is less than 1.0 times the relative speed of the metal plate 1, the stirring performance is reduced, the effect of removing the vapor film on the surface of the metal plate 1 is not sufficiently obtained, and the metal plate ( 1) The cooling effect is not sufficiently obtained. In addition, the peripheral speed of the roll 4 is preferably 3.0 times or less relative to the running speed of the metal plate 1. If the peripheral speed of the roll 4 is a relative speed of 3.0 times or less with respect to the running speed of the metal plate 1, it becomes easy to suppress the formation of scratches on the surface of the metal plate 1.

The direction of rotation of the roll 4 (roll 4a, roll 4b) is not limited, but in order to more efficiently improve the stirring performance of the vapor film on the surface of the metal plate 1, the roll 4 is connected to the metal plate ( 1) It is desirable to rotate in the direction opposite to the traveling direction (see FIG. 1). Moreover, the maximum height roughness Rz of the surface of the roll 4 (roll 4a, roll 4b) is preferably 10 μm or more. When the maximum height roughness Rz of the roll surface is 10 μm or more, the stirring performance increases, the effect of removing the vapor film on the surface of the metal plate 1 becomes higher, and a better cooling effect is easily obtained. Moreover, the maximum height roughness Rz of the surface of the roll 4 (roll 4a, roll 4b) is preferably 50 μm or less. If the maximum height roughness Rz of the roll surface is 50 μm or less, it becomes easy to suppress the formation of scratches on the surface of the metal plate 1. In addition, here, the maximum height roughness Rz of the roll surface is defined in JIS B 0601 (2001), and may be measured by the measurement method described in JIS B 0633. Additionally, the measuring method may be a stylus type or a non-contact type. Additionally, the quenching device 11 may be provided with a control device (not shown) that controls the rotation speed and rotation direction of the rolls 4 (rolls 4a and 4b) as described above. In addition, by controlling the output of the main motor 45 (see FIG. 3) that rotationally drives the roll 4 by the control device, the rotational speed and rotation direction of the roll 4 can be controlled through the spindle 44. do.

Moreover, the roll diameter of roll 4 (roll 4a, roll 4b) is preferably 50 mm or more. If the roll diameter is less than 50 mm, bending of the roll 4 is likely to occur due to the reaction force from the metal plate 1. Moreover, the roll diameter of roll 4 (roll 4a, roll 4b) is preferably 250 mm or less. If the roll diameter is 250 mm or less, the stirring performance increases, the effect of removing the vapor film on the surface of the metal plate 1 increases, and a better cooling effect is easily obtained.

The number of rolls arranged in the tank 5 is not limited, but at least one pair of rolls needs to be arranged so that the metal plate 1 is sandwiched between them. Also, preferably, if a plurality of rolls are arranged on each of the front and back sides of the metal plate 1, the vapor film can be removed more uniformly and reliably, and stable cooling performance can be obtained. In order to obtain the same cooling capacity on the front and back surfaces of the metal plate 1, it is preferable that the number of rolls disposed on the front and back sides of the metal plate 1 is equal, and that they are arranged in pairs. The number of rolls is preferably 3 pairs or more. If the number of rolls is three or more, the vapor film on the surface of the metal plate 1 can be removed more uniformly and reliably, making it easier to obtain stable cooling performance. There is no particular upper limit to the number of rolls 4, but the number of rolls is preferably 10 pairs or less. It is preferable in terms of cost if the number of roll batches is 10 pairs or less. Additionally, the rolls may or may not be in contact with each other. In addition, in the cooling device in the present invention, by stirring the cooling medium (liquid) with a roll, the effect of removing the vapor film on the surface of the metal plate is obtained, and an excellent cooling effect on the metal plate is obtained. There is no need to install coolant spray nozzles within the tank of the device.

The material of the rolls 4 (rolls 4a, 4b) may be formed of a material with a strength that can withstand the reaction force of the metal plate 1. For example, SUS304, SUS310, ceramic, etc. can be mentioned.

FIG. 2 is a diagram showing the state of the quenching device 11 under conditions in which quenching is not performed. In addition, Figures 1 and 2 differ only in the state of the quenching device 11 (a state in which quenching is performed, a state in which quenching is not performed), and the basic state of the quenching device 11 is different. Since the configuration is the same, the components corresponding to the quenching device 11 in Fig. 1 are given the same reference numerals and their detailed description is omitted. Additionally, in the cooling device 11 in the state shown in FIG. 2, the cooling medium (liquid (water)) 2 contained in the tank 5 in the state shown in FIG. 1 is removed, and the tank 5 is empty. In addition, when quenching is not performed, the cooling medium contained in the tank 5 may be completely removed from the tank 5, and may remain in the tank 5 to the extent that the metal plate 1 is not immersed. do.

As shown in Fig. 2, when quenching is not performed, the positions of the rolls 4 (rolls 4a and 4b) are higher than the positions when quenching is performed. (in other words, the gap between the rolls 4a and 4b is changed to become larger). That is, the distance of the roll 4 of this embodiment from the metal plate 1 can be changed. Therefore, the roll 4 has a drive mechanism (motor) that moves the roll 4 to a position away from the metal plate 1. Additionally, if the roll 4 can be moved as described above, the method is not particularly required, but considering responsiveness, an electric type is more preferable. As an example, Fig. 3 shows the moving mechanism of the roll 4 (roll 4a, roll 4b). FIG. 3(a) is a bird's-eye view of the moving mechanism from above, and FIG. 3(b) is a side view of a part of the moving mechanism seen from the side. As a moving mechanism of the roll 4, for example, as in the embodiment shown in FIG. 3, the rotation axis of the roll 4 (roll 4a, roll 4b) surrounds the outer periphery of the tank 5. (41) Arms (arms with linear guides) (6) connected to the bearing mechanisms (43) at both ends are installed, and each arm (6) is moved in the horizontal direction by an electric jack (7), thereby forming a roll ( 4) There is a mechanism for changing the distance between (roll 4a, roll 4b) and the metal plate 1. The arm 6 is installed on each of the rolls 4 (rolls 4a and 4b) on the front and back sides of the metal plate 1 and moved in the horizontal direction to move the rolls 4 in the horizontal direction. Movement (opening and closing of the gap between rolls 4a and rolls 4b) becomes possible. Additionally, a sealing mechanism 42 (mechanical seal) can be appropriately installed in the area of the connection between the rotating shaft 41 of the roll 4 and the tank 5 to prevent leakage of the cooling medium from the tank 5.

In Fig. 2 (condition without quenching), in order to reduce heat radiation from the metal plate 1, the rolls 4 (rolls 4a, rolls 4b) are separated from the metal plate 1. do. At this time, it is desirable to separate each of the rolls 4a and 4b from the metal plate 1 as much as possible, and the distance between the rolls 4a and the rolls 4b and the metal plate 1 is 200 mm or more. It is desirable. Specifically, as shown in Fig. 2, it is preferable that the distance between the rolls 4a, 4b, and the metal plate 1 is 200 mm or more in the horizontal direction. Furthermore, by separating the roll 4 from the metal plate 1 in this way, damage to the roll 4 due to rattling of the metal plate can also be avoided. Additionally, in the state shown in FIG. 2, the operation may be performed with the rotation of the roll 4 stopped.

As described above, the quenching device 11 of the present embodiment uses the roll 4 ( The distance between the rolls 4a, 4b) and the metal plate 1 can be changed. When performing quenching, the roll 4 is brought close to the metal plate 1, the vapor film on the metal plate 1 is agitated and removed by the roll 4, and cooling is performed to ensure sufficient cooling capacity. . As a result, in the present invention, it is possible to make it unnecessary to install a nozzle for cooling the metal plate 1. In addition, when quenching is not performed, the roll 4 is separated from the metal plate 1 to suppress thermal deformation of the roll 4 due to heat radiation from the metal plate 1, and installation of a reflector is possible. There is no need to consider the deformation of the nozzle within the tank. As a result, when performing quenching, an excellent cooling effect on the metal plate 1 is obtained, and, for example, the conditions for performing quenching on the metal plate 1 heated in a continuous annealing equipment When switching to conditions where over-quenching is not performed, the furnace of the continuous annealing equipment is opened, or in order to prevent thermal deformation caused by heat radiation from the metal plate 1, the quenching device is adjusted. The conversion is easy because there is no need to remove a member such as a coolant spray nozzle or install a reflector to prevent thermal deformation within the tank. Therefore, both metal plates that require quenching and metal plates that do not require quenching can be manufactured with high productivity using a single quenching device.

The present invention is preferably applied to a steel plate manufacturing method. In particular, if the quenching device of the present invention is installed on the exit side of the crack furnace of a continuous annealing facility in which steel sheets of different steel types are continuously sheeted, it can be utilized more effectively. In addition, it is also possible to adjust the installation position of the roll and the arrangement relationship with the metal plate running in the tank of the quenching device, and use the quenching device to correct the shape of the metal plate.

The above-mentioned steel sheets include cold-rolled steel sheets, hot-dip galvanized steel sheets, electro-galvanized steel sheets, and alloyed hot-dip galvanized steel sheets obtained by surface treating them. The present invention is preferably applied to a method of manufacturing a cold-rolled steel sheet that refers to a cold-rolled steel sheet after annealing, and is also applied to a method of manufacturing a plated steel sheet that applies a plating treatment to the cold-rolled steel sheet. The plating treatment may include one or more selected from electric zinc plating, hot-dip galvanizing, alloyed hot-dip galvanizing, etc. In addition, the embodiment of the present invention is not limited to the example of manufacturing steel plates, and can be applied to the overall production of metal plates other than steel plates.

Example

An embodiment of the present invention is described. However, the present invention is not limited to the following examples.

In this example, the cooling device after processing high-strength steel sheets with a thickness of 0.8 to 2.3 mm using a continuous annealing equipment was changed. Specifically, in this embodiment, a quenching device is installed on the output side of the continuous annealing equipment, and the high-strength steel sheet is annealed in the continuous annealing equipment, and then a steel sheet (coil) with a target tensile strength of 780 MPa to 1470 MPa is formed. , an example in which a steel sheet (coil) with a target tensile strength of 340 MPa to 590 MPa was manufactured using the same quenching device is shown.

＜Conventional example＞

As a conventional example, the quenching device described in Patent Document 2 was installed on the output side of the continuous annealing equipment. In order to obtain the mechanical properties of a steel sheet with a tensile strength target of 780 MPa to 1,470 MPa, quenching (water quenching) is performed using the above-mentioned quenching device, and 200 coils of a tensile strength target of 780 MPa to 1,470 MPa are formed. Manufactured. Subsequently, 200 coils with a target tensile strength of 340 MPa to 590 MPa were manufactured. At this time, since water quenching was unnecessary, water was drained from the water tank of the quenching device, and a protective reflector was installed on the water spray nozzle installed in the water tank. The steel sheet after continuous annealing was run in the water tank of the quenching device in this state, and 200 coils with a target tensile strength of 340 MPa to 590 MPa were manufactured. As a result, the reflector was thermally deformed.

＜Comparative example＞

As a comparative example, the above-described quenching device 11 (however, the rolls 4 (rolls 4a, 4b) were forcibly fixed so as not to rotate) was installed on the output side of the continuous annealing equipment. did. In order to obtain the mechanical properties of a steel sheet with a tensile strength target of 780 MPa to 1470 MPa, rapid cooling (water quenching) is necessary. Therefore, water was placed in the water tank 5 as shown in Fig. 1, and cooling was performed without rotating the roll 4. The position of the rolls 4 (rolls 4a, rolls 4b) at this time was set at a position in contact with the steel plate running in the water tank 5. Under these conditions, 200 coils with a target tensile strength of 780 MPa to 1470 MPa were manufactured, and in 120 of them, mechanical strength was not obtained due to insufficient cooling. Thereafter, as shown in FIG. 2, the rolls 4 (rolls 4a, 4b) are separated from the steel plate by 500 mm in the horizontal direction, and water is drained from the water tank 5. 200 coils with a target tensile strength of 340 MPa to 590 MPa were manufactured. As a result, it was confirmed that there was no damage such as thermal strain due to heat influence from the steel plate, and the target tensile strength was obtained. In this comparative example, when manufacturing a coil with a target tensile strength of 780 MPa to 1470 MPa, a sufficient cooling effect was not obtained, the yield decreased, and productivity decreased.

<Example of the present invention>

As an example of the present invention, the quenching device 11 described above was installed on the output side of the continuous annealing equipment. In order to obtain the mechanical properties of a steel sheet with a tensile strength target of 780 MPa to 1470 MPa, rapid cooling (water quenching) is necessary. Therefore, water was placed in the water tank 5 as shown in Fig. 1, and the rolls 4 (rolls 4a and 4b) were rotated to cool the steel sheet. The position of the rolls 4 (rolls 4a, rolls 4b) at this time was set at a position in contact with the steel plate running in the water tank 5. Here, the maximum height roughness Rz of the surface of the roll 4 was set to 20 μm, and the roll diameter of the roll 4 was set to 150 mm.

(Example 1)

In Example 1, the rotation direction of the steel sheet and the roll 4 (roll 4a, roll 4b) is the same, and the peripheral speed is 2.0 times the running speed of the steel sheet (if the steel sheet is 1000 mm/s, the roll peripheral speed is The roll was rotated at 2000 mm/s, and the peripheral speed of the roll was 2.0 times the relative speed with respect to the running speed of the metal plate 1. Under these conditions, 200 coils with a target tensile strength of 780 MPa to 1470 MPa were manufactured, and as a result, an excellent cooling effect was obtained, and the target strength was achieved in all coils. Thereafter, as shown in FIG. 2, the rolls 4 (rolls 4a, 4b) are separated from the steel plate by 500 mm in the horizontal direction, and water is drained from the water tank 5. 200 coils with a target tensile strength of 340 MPa to 590 MPa were manufactured. As a result, it was confirmed that there was no damage such as thermal strain due to heat influence from the steel plate, and the target tensile strength was obtained. Additionally, in Example 1, when switching between the conditions for performing quenching and the conditions for not performing quenching, the member in the water tank 5 of the quenching device 11 was removed or a reflector was installed in the water tank 5. Didn't install. Therefore, the conversion is easy, and both steel sheets that require quenching and steel sheets that do not require quenching can be manufactured with high productivity using a single quenching device.

(Example 2)

In Example 2, the rotation directions of the steel sheet and the rolls 4 (rolls 4a and 4b) were reversed, and the rolls 4 were rotated at the same peripheral speed as the steel sheet traveling speed (steel sheet 1000 mm/s) In this case, the roll peripheral speed is 1000 mm/s, and the peripheral speed of the roll 4 is 2.0 times the relative speed with respect to the running speed of the metal plate 1). Under these conditions, 200 coils with a target tensile strength of 780 MPa to 1470 MPa were manufactured, and as a result, an excellent cooling effect was obtained, and the target strength was achieved in all coils. Thereafter, as shown in FIG. 2, the rolls 4 (rolls 4a, 4b) are separated from the steel plate by 500 mm in the horizontal direction, and water is drained from the water tank 5. 200 coils with a target tensile strength of 340 MPa to 590 MPa were manufactured. As a result, it was confirmed that there was no damage such as thermal strain due to heat influence from the steel plate, and the target tensile strength was obtained. Additionally, in Example 2, when switching between the conditions for performing quenching and the conditions for not performing quenching, the member in the water tank 5 of the quenching device 11 was removed or a reflector was installed in the water tank 5. Didn't install. Therefore, the conversion is easy, and both steel sheets that require quenching and steel sheets that do not require quenching can be manufactured with high productivity using a single quenching device.

As a result, the effectiveness of the present invention was confirmed.

1: metal plate
2: Cooling medium (liquid (water))
3: Sink roll
4 (4a, 4b): roll
5: Tank (water tank)
6: Arm (arm with linear guide attached)
7: Electric jack
11: Qing device
41: Rotation axis of roll
42: seal mechanism
43: Bearing mechanism
44: spindle
45: cycle motor

Claims (8)

As a cooling device for cooling a metal plate,
a tank containing a cooling medium into which the metal plate is immersed;
In the tank, at least one pair of rolls is disposed so as to sandwich the metal plate running in the tank, the distance to the metal plate can be changed, and the roll rotates at a peripheral speed equal to or higher than the traveling speed of the metal plate. , ??qing device. According to claim 1,
The roll rotates in a direction opposite to the traveling direction of the metal plate. The method of claim 1 or 2,
A quenching device installed on the exit side of the crack furnace of a continuous annealing facility. A quenching method of cooling a metal plate using a quenching device provided with a tank containing a cooling medium into which the metal plate is immersed, comprising:
When performing quenching by immersing a metal plate in a cooling medium,
The metal plate is driven through a tank containing a cooling medium, and at least one pair of rolls arranged in the tank so as to sandwich the metal plate running through the tank is operated at a speed higher than or equal to the traveling speed of the metal plate. Cooling the metal plate by rotating it at a high speed,
If quenching is not performed by immersing the metal plate in the cooling medium,
A quenching method in which the metal plate is driven through a tank that does not contain a cooling medium, and the at least one pair of rolls is arranged further away from the metal plate than in the arrangement in which the quenching is performed. . According to claim 4,
A quenching method in which the roll is rotated in a direction opposite to the traveling direction of the metal plate. A method for manufacturing a cold-rolled steel sheet, wherein the metal plate is a cold-rolled steel sheet, and the cold-rolled steel sheet after annealing is quenched by the quenching method according to claim 4 or 5. A method of manufacturing a plated steel sheet, comprising subjecting a steel sheet obtained by the method of manufacturing a cold rolled steel sheet according to claim 6 to plating. According to claim 7,
A method of manufacturing a plated steel sheet, wherein the plating treatment is selected from electrogalvanizing treatment, hot-dip galvanizing treatment, and alloyed hot-dip galvanizing treatment.