Draining device during passage of metal plate and draining method during passage of metal plate

Abstract

To provide a technique effectively removing scattered water in a space above a metal plate and water droplets on a top surface of the metal plate during plate passing.SOLUTION: A device of draining metal plate during plate passing comprises the steps of: passing a plate through a transfer line; watering and draining in order through a watering appliance and a fluid jet type draining appliance installed side by side to the watering appliance; and winding the metal plate by a winder after a prescribed inspection by an inspection device. The device of draining metal plate during plate passing includes: a first blower installed at an upper side in a plate passing direction between the fluid jet type draining appliance and the inspection device in which the first blower blows air flow from a direction opposite to the plate passing direction of the metal plate to the top surface of the metal plate; and a second blower installed on an upper side of the metal plate at the end part thereof in a width direction between the first blower and the inspection device in which the second blower blows air flow from a direction approximately orthogonal to the plate passing direction of the metal plate to the top surface of the metal plate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water drainage technique during the passage of a metal plate. In particular, it relates to an apparatus and method for effectively eliminating water droplets that cause false detection by a flaw detection device in a hot rolling line, removing water scattered in the space above the hot-rolled metal plate during passage and water droplets on the upper surface of the hot-rolled metal plate.

Background Art

[0002] In the hot rolling of metal plates, particularly steel plates, in recent years, an apparatus for online flaw detection of hot-rolled and cooled steel plates has been installed and is in operation.

[0003] To cool the steel plate after hot rolling, a large amount of water is required. Therefore, a large amount of water remains on the steel plate, and flaw detection cannot be performed as it is. Therefore, to remove the remaining water, there is a device that injects high-pressure water in the direction opposite to the advancing direction of the plate passing line. For example, Patent Document 1 discloses means such as injecting high-pressure air from a direction substantially orthogonal to the plate passing line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above prior art has the following problems. That is, only the reverse injection of high-pressure water or the injection of air from a direction substantially orthogonal to the plate passing line left some water droplets remaining on the steel plate, which caused false detection by the flaw detection device. In addition, the cooling water was wound up by the rotation of the steel plate conveying roll and scattered above the steel plate as water droplets, and these water droplets fell onto the steel plate, which was another cause of false detection by the flaw detection device.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an apparatus and a method for effectively removing water scattered in the space above the metal plate during continuous passing of the metal plate and water droplets on the upper surface of the metal plate.

Means for Solving the Problems

[0007] The water draining device for a metal plate according to the present invention that advantageously solves the above problems is a water draining device for a metal plate that is passed through a conveying line, sequentially watered and drained by a water spraying facility and a fluid jet type water draining facility provided in the water spraying facility, and then taken up by a winder after undergoing a predetermined inspection by an inspection device. The water draining device is installed above the metal plate passing direction between the fluid jet type water draining facility and the inspection device, and includes a first blower that blows air toward the upper surface of the metal plate from a direction opposite to the metal plate passing direction, and a second blower that is installed above the end portion in the width direction of the metal plate between the first blower and the inspection device and blows air toward the upper surface of the metal plate from a direction substantially orthogonal to the metal plate passing direction.

[0008] In addition, the water draining device for a metal plate according to the present invention (a) the first blower is a plurality of blowers, and the air flow blown from the first blower extends over the entire width direction of the metal plate, (b) the first blower is arranged such that the blower arranged on the end side of the metal plate is arranged downstream in the metal plate passing direction from the blower on the central side, (c) the second blower is composed of a plurality of blowers and is respectively arranged at both ends of the metal plate, (d) the metal plate is a hot-rolled steel plate, and the water spraying facility is a cooling facility for the hot-rolled steel plate, etc. can be considered to be more preferable solution means.

[0009] The method for draining water during the passage of a metal plate according to the present invention, which advantageously solves the above problems, is a method for draining water for a metal plate that is passed through a conveying line, sequentially watered and drained by a water spraying facility and a fluid injection type water draining facility installed in parallel with the water spraying facility, and then wound by a winder after undergoing a predetermined inspection by an inspection device. The method includes a step of blowing an air current in a direction opposite to the passage direction of the metal plate toward the upper surface of the metal plate from a first blower installed above the metal plate passage direction between the fluid injection type water draining facility and the inspection device, to drop the water scattered above the metal plate downward; and a step of blowing an air current in a direction substantially orthogonal to the passage direction of the metal plate toward the upper surface of the metal plate from a second blower installed above an end portion in the width direction of the metal plate between the first blower and the inspection device, to remove the water dropped onto the metal plate outside the surface of the metal plate.

[0010] In addition, the method for draining water during the passage of a metal plate according to the present invention is (e) blowing the air current from the first blower over the entire width direction of the metal plate, and the central axis of the air current intersects the metal plate on the upstream side in the passage direction of the metal plate with the central side in the width direction being upstream of the end side in the width direction; (f) arranging the air currents from the second blower blown from both sides of the metal plate with the central axes of the respective air currents shifted in a top view so that the air currents do not interfere with each other; (g) using the metal plate as a hot-rolled steel plate, cooling it with the water spraying facility and then draining the water, etc. can be considered as more preferable solution means.

Effect of the Invention

[0011] According to the water draining device and method during the passage of a metal plate according to the present invention, it is possible to prevent water droplets scattered above the steel plate, which is a metal plate, from being reflected in the surface defect detection device. The frequency of false detection in the surface defect inspection can be significantly reduced, and the surface defect detection accuracy in the on-line inspection can be greatly improved. As a result, the load of the visual inspection work of the steel plate performed by the operator according to the surface defect oversight or surface defect detection result can be significantly reduced. In addition, an effect that a compressor for injecting high-pressure air used conventionally becomes unnecessary and the operation cost is significantly reduced can also be obtained.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic diagram of a water draining device during continuous running of a hot-rolled metal sheet according to an embodiment of the present invention, where (a) shows a top view and (b) shows a front view seen from the operator side. [Figure 2] It is a schematic diagram showing the flow analysis results of scattered water and air flow in the blower arrangement case A of the above device, where (a) is a top view showing the blower arrangement and (b) is a perspective view showing the streamlines of the scattered water and air flow. [Figure 3] It is a schematic diagram showing the flow analysis results of scattered water and air flow in the blower arrangement case B of the above device, where (a) is a top view showing the blower arrangement and (b) is a perspective view showing the streamlines of the scattered water and air flow. [Figure 4] It is a schematic diagram showing the flow analysis results of scattered water and air flow in the blower arrangement case C of the above device, where (a) is a top view showing the blower arrangement and (b) is a perspective view showing the streamlines of the scattered water and air flow. [Figure 5] It is a schematic diagram showing the flow analysis results of scattered water and air flow in the blower arrangement case D of the above device, where (a) is a top view showing the blower arrangement and (b) is a perspective view showing the streamlines of the scattered water and air flow. [Figure 6] It is a schematic diagram showing the influence of the inclination angle of the blower in the blower arrangement case A of the above device on the flow analysis results of scattered water and air flow, where (a) shows the case of an inclination angle of 5°, (b) shows the case of an inclination angle of 25°, and (c) shows the case of an inclination angle of 45°.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be specifically described. Further, the following embodiments illustrate facilities and methods for embodying the technical idea of the present invention, and do not specify the configuration to the following ones. That is, the technical idea of the present invention can be variously modified within the technical scope described in the claims.

[0014] FIG. 1 is a schematic diagram of a water draining device during passage of a metal plate according to an embodiment of the present invention. FIG. 1(a) shows a top view. FIG. 1(b) shows a front view seen from the operator side.

[0015] In the example of FIG. 1, a water draining device installed between a cooling facility 3 and a flaw detection device 8 at the subsequent stage of a hot rolling line will be described. In hot rolling for manufacturing the metal plate 1, in recent years, particularly in the case of the steel plate 1, a flaw detection device 8 for detecting flaws on the surface of the hot-rolled steel plate is installed online between cooling the steel plate 1 after finish rolling and the coiler 10, and flaw inspection may be performed. A pinch roll 9 for adjusting the tension of the steel plate is arranged immediately before the coiler 10.

[0016] For example, in the facility of FIG. 1, the steel plate 1 passed through the hot rolling line is cooled by cooling water injected from the cooling facility 3 after being rolled by the finish rolling mill 2. At this time, if even a part of the cooling water poured from the cooling facility 3 on the outlet side of the finish rolling mill 2 onto the steel plate 1 remains as water droplets on the upper surface of the steel plate 1, the water droplets may be misdetected as flaws, leading to a decrease in flaw detection accuracy.

[0017] For example, in the prior art described in Patent Document 1, a water jet type water draining facility 4 that injects high-pressure water obliquely upstream from both ends in the width direction of the steel plate 1 is provided. Thereby, it is said to eliminate the stagnant water on the steel plate. Further, high-pressure air injection is performed by an air nozzle group substantially orthogonal to the passing direction of the steel plate to remove the water droplets remaining on the upper surface of the steel plate 1 outside the steel plate surface.

[0018] However, in the online flaw detection device 8, false detection by water droplets cannot be sufficiently prevented. Regarding the cause, when the inventors investigated in detail, they grasped that when the passing speed of the steel plate 1 is high, that is, when the rotational peripheral speed of the conveying roller 5 is fast, the cooling water is lifted up by the rotation of the conveying roller 5. And they grasped that a phenomenon occurs in which the lifted cooling water scatters into the space above the steel plate 1, and this scattered water may reach the flaw detection device 8 in a floating state in the space.

[0019] The conventional draining device is designed for the water droplets remaining on the upper surface of the steel plate 1 after removing the cooling water staying on the upper surface of the steel plate 1 by water injection. For the water droplets scattered and floating in the space above the steel plate 1, the injection area of air was too narrow for the air to hit, and the effect of removing the scattered water floating in the space could not be obtained.

[0020] Therefore, in this embodiment, a large blower as shown in FIG. 1 is arranged to obtain an air flow in a wide range.

[0021] First, the first blower 6 is installed above the steel plate 1 between the water injection type draining facility 4 and the flaw detection device 8. Then, an air flow is blown downward toward the surface of the steel plate 1 from the direction opposite to the passing direction PL of the steel plate 1. In order to surely drop the water droplets in the space above the steel plate 1, it is preferable that the first blower 6 generates an air flow having a width covering the entire width direction of the steel plate. When the width of the air flow is insufficient with a single blower, it is preferable to use a plurality of blowers.

[0022] When the first blower 6 is composed of a plurality of blowers, it is preferable to arrange the blower arranged on the end side of the steel plate 1 downstream in the passing direction of the metal plate than the blower on the central side. The scattered water can be blown down to the steel plate side and blown out to the outside in the width direction of the steel plate 1. When installing a plurality of blowers, if they are arranged side by side in the width direction, a gap is formed between the blowers when viewed from the passing direction PL, and a region with a slow air flow velocity is generated, and there is a concern that the scattered water may slip through. On the contrary, if the blower arranged on the end side of the steel plate 1 is arranged upstream in the passing direction of the metal plate than the blower on the central side, the scattered water that has been blown down will be collected in the center, and there is a possibility that it will remain on the upper surface of the steel plate 1 as water droplets.

[0023] The spatial height at which the scattered water exists depends on the peripheral speed of the transport rollers 5, i.e., the sheet passing speed of the steel sheet 1. When the sheet passing speed is 20 m / s (1200 m / min), it is approximately 2 m. Therefore, it is preferable that the first fan 6 blows down from a height higher than this. The first fan 6 is preferably a fan specified in JIS B 0132:2005 that can generate an airflow with a wind speed of 17 m / s or more. It is capable of removing water droplets with a diameter of approximately 3 mm. Since a compressor is required to achieve a wind speed of more than 100 m / s, it is preferable that the upper limit be 100 m / s. More preferably, the wind speed is 30 m / s or less.

[0024] The inclination angle of the first fan 6, as an angle inclined from the vertical to the upstream side in the sheet passing direction PL, is preferably more than 5° and less than 45°. It is preferably 10° or more and 30° or less. If the inclination angle is outside this preferable range, there is a concern that splashed water may slip through.

[0025] The second blower 7 is installed above the widthwise end of the steel sheet 1 between the first blower 6 and the flaw detector 8 in the sheet passing direction PL. The airflow direction of the second blower 7 is blown in a direction approximately perpendicular to the sheet passing direction PL. In the present invention, the direction perpendicular to the sheet passing direction PL is allowed to be a direction up to 90°±10° from the sheet passing direction PL. The second blower 7 has the function of efficiently removing splashed water blown down onto the upper surface of the steel sheet 1 by the first blower from one widthwise end of the steel sheet 1 to the other. In this regard, it is preferable that the depression angle of the second blower 7 looking down on the steel sheet 1 is 15° or less. Preferably, the depression angle is greater than 0° and less than 10°.

[0026] The second blower 7 is preferably installed on both sides of the steel plate 1. It is preferable to shift the central axis of the air flow of each blower in a top view so that the air flows do not interfere with each other. Further, it is preferable to direct the central axis of the air flow near the center in the width direction of the steel plate 1. The second blower 7 is preferably a blower defined in JIS B 0132:2005 and capable of generating an air flow with a wind speed of 17 m / s or more. It can remove water droplets with a diameter of about 3 mm. Since a compressor is required to exceed a wind speed of 100 m / s, it is preferable to set 100 m / s as the upper limit. More preferably, the wind speed is 30 m / s or less.

[0027] In the above embodiment, the draining device between the water-cooling cooling device 3 and the flaw detection device 8 in the hot rolling equipment of the steel plate 1 has been described. As the water injection type draining equipment 4, a fluid injection type draining device such as high-pressure air can also be used. Further, after water is sprayed on the rolls of the finishing rolling mill 2, a draining device similar to that of the present embodiment can be installed in the section from the optical plate width meter to the inspection device 8.

[0028] As the metal plate, it can be applied not only to hot-rolled steel plates but also to cold-rolled steel plates, copper strip plates, and aluminum strip plates. The water spraying equipment 3 may be not only a cooling equipment but also a cleaning equipment using water. As the inspection device 8, various optical inspection devices such as an image processing device and a light reflection type width meter can be applied.

Example

[0029] (Example 1) <casea> In the hot rolling equipment of FIG. 1, the possibility of removing scattered water was examined by fluid analysis with the arrangement of the first blower 6 and the second blower 7 shown in FIG. 2(a). Simcenter STAR-CCM+ was used as the fluid analysis software. The width of the steel plate 1 was set to 1.5 m, and the passing speed was set to 20 m / s. Both the first blower 6 and the second blower 7 were circular with a diameter of 700 mm, and the air flow FA had an air speed of 20 m / s. The central axis of the air flow of the first blower 6 was inclined 25° from the vertical direction to the upstream side of the passing direction PL of the steel plate 1. The depression angle of the second blower 7 was set to 10°. The scattered water FD was assumed to move in the passing direction at 5 m / s as the initial condition at the entrance of the calculation space. The fluid analysis results are shown in FIG. 2(b).

[0030] In CaseA, the air flow from the first blower 6 is blown down over the entire width direction of the steel plate 1. And the central axis of the air flow intersects the steel plate 1 on the upstream side of the passing direction PL of the steel plate 1 with the central side in the width direction being upstream of the end side in the width direction. In CaseA, there is no trajectory of the scattered water FD passing through the upstream and downstream of the steel plate 1 within the calculation space, and all of it can be removed to the outside of the side of the steel plate 1.

[0031] <caseb> For Case A, a similar fluid analysis was performed by only changing the arrangement of the first blower shown in Fig. 3(a). The results are shown in Fig. 3(b).

[0032] In Case B, the airflow from the first blower 6 is blown down over the entire width direction of the steel plate 1. And the central axis of the airflow intersects the steel plate 1 on the downstream side of the steel plate 1 in the passing direction PL at the width direction center side rather than the width direction end side. In Case B, a trajectory of the scattered water FD that escapes through the central part in the width direction directly above the steel plate 1 is observed. Depending on the amount of the scattered water, there is a possibility that the second blower cannot remove the water droplets on the steel plate 1.

[0033] <casec> For Case A, a similar fluid analysis was performed by only changing the arrangement of the first blower shown in Fig. 4(a). The results are shown in Fig. 4(b).

[0034] In Case C, the first blowers 6 are arranged side by side in the width direction of the steel plate 1. Due to the equipment configuration, a gap is generated between the blowers. The trajectory of the scattered water FD passes through the gap between the upper blowers and may reach the flaw detection device 8 through a position higher than the air flow of the second blower 7.

[0035] <cased> For Case A, fluid analysis was performed after changing the arrangement such that the second blower 7 shown in Fig. 5(a) is placed upstream of the first blower 6. The results are shown in Fig. 5(b).

[0036] In Case D, the scattered water that has overcome the airflow from the second blower 7 passes through downstream on the steel plate 1. The passing speed of the steel plate 1 is high, and the airflow from the second blower 7 is pulled in the passing direction of the steel plate, interfering with the airflow blown down by the first blower, and the floating and dropping of water droplets are not sufficiently carried out.

[0037] (Example 2) With the same blower arrangement as in Case A, the inclination angle of the first blower was changed, and the results of the fluid analysis are shown in Fig. 6. Case A1 shown in Fig. 6(a) has an inclination angle of 5° from the vertical direction to the upstream side of the passing direction PL of the steel plate. Case A2 shown in Fig. 6(b) has an inclination angle of 25° from the vertical direction to the upstream side of the passing direction PL of the steel plate, similar to Case A. Case A3 shown in Fig. 6(c) has an inclination angle of 45° from the vertical direction to the upstream side of the passing direction PL of the steel plate.

[0038] In Case A1, the airflow blown down from the first blower 6 is pulled by the steel plate and interferes with the airflow of the second blower 7 on the downstream side. There is a risk that the water droplets blown onto the steel plate 1 may reach the flaw detection device 8.

[0039] In Case A2, there is no trajectory of the scattered water FD passing through from upstream to downstream of the steel plate 1 within the calculation space, and all of it can be removed to the outside of the side of the steel plate 1.

[0040] In Case A3, the vertical component of the airflow of the first blower 6 is small, and there is a risk that it may not be able to sufficiently blow down the scattered water. There is a risk that the passing scattered water may reach the flaw detection device 8.

[0041] The results of each case in Example 1 and Example 2 are summarized and shown in Table 1. In the evaluation of the water removal effect in Table 1, an open circle (〇) indicates good water removal, a triangle (△) indicates that water removal is possible in some cases, and a cross (×) indicates that water removal cannot be expected.

[0042]

Table 1

[0043] (Example 3) With the equipment layout shown in Fig. 1, a steel plate with a plate passing speed of 20 m / s was hot-rolled, cooled, and wound into a coil with the specifications of the blower in Case A (inventive example). As a conventional example, a water draining device that blows air at 0.5 MPa from the side of the steel plate 1 using a compressor was used with the configuration shown in Patent Document 1.

[0044] In the conventional example, there were false detections due to water droplets in 10 coils out of 100 coils, and it was necessary to conduct visual observation on a separate line. On the other hand, in the inventive example, there was a false detection due to water droplets in only 1 coil out of 100 coils, and it was necessary to conduct visual observation on a separate line. The inventive example was able to reduce false detections by 90% compared to the conventional example.

Industrial Applicability

[0045] According to the water draining device and method for passing a metal plate of the present invention, it is possible to prevent water droplets scattered above the metal plate from being falsely detected by an optical inspection device, and it contributes to improving productivity such as being able to omit visual inspection. Since a compressor is not used, it also leads to a reduction in equipment costs. Therefore, it is industrially useful.

Explanation of Signs

[0046] 1 Steel plate (metal plate) 2 Finishing rolling mill 3 Cooling equipment (water spraying equipment) 4 Water injection type water draining equipment (fluid injection type water draining equipment) 5 Conveyor roller 6 First fan (blower) 7 Second fan (blower) 8 Defect detection device (inspection device) 9 Pinch roll 10 Take-up machine PL Pass line (direction of metal sheet passing) FD Scattered water FA Airflow< / cased> < / casec> < / caseb> < / casea>

Claims

1. A draining device for a metal plate that is passed through a conveying line, sequentially wetted and drained by a wetting facility and a fluid injection type draining facility installed together with the wetting facility, then subjected to a predetermined inspection by an inspection device, and then wound up by a winder, comprising: A first blower installed above the metal plate passing direction between the fluid injection type draining facility and the inspection device, and blowing an air current toward the upper surface of the metal plate from a direction opposite to the metal plate passing direction; A second blower installed above the end portion in the width direction of the metal plate between the first blower and the inspection device, and blowing an air current toward the upper surface of the metal plate from a direction substantially orthogonal to the metal plate passing direction; having: One or more of the first blowers are arranged; When there are a plurality of the first blowers, they are arranged so that the air current from the first blowers does not concentrate on the center in the width direction of the metal plate; A draining device for a metal plate during passing, wherein an inclination angle of the first blower is in a range of 5 to 45° from the vertical direction to the upstream side in the passing direction.

2. The draining device for a metal plate during passing according to Claim 1, wherein the first blower is a plurality of blowers, and the air current blown from the first blowers extends over the entire width direction of the metal plate when viewed in the metal plate passing direction.

3. The draining device for a metal plate during passing according to Claim 2, wherein the first blower is arranged such that a blower arranged on the end side of the metal plate is arranged downstream in the metal plate passing direction from a blower on the center side.

4. The draining device for a metal plate during passing according to Claim 1, wherein the second blower is composed of a plurality of blowers and is respectively arranged at both end portions of the metal plate.

5. The draining device for a metal plate during passing according to Claim 1, wherein the metal plate is a hot-rolled steel plate, and the wetting facility is a cooling facility for a hot-rolled steel plate.

6. A draining method for a metal plate that is passed through a conveying line, sequentially wetted and drained by a wetting facility and a fluid injection type draining facility installed together with the wetting facility, then subjected to a predetermined inspection by an inspection device, and then wound up by a winder, comprising: A first step of blowing an air current in a direction opposite to the metal plate passing direction toward the upper surface of the metal plate from one or more first blowers installed above the metal plate passing direction between the fluid injection type draining facility and the inspection device, and dropping the water scattered above the metal plate downward; a second step of blowing an airflow from a second fan installed above an end of the metal plate in the width direction between the first fan and the inspection device toward the upper surface of the metal plate in a direction substantially perpendicular to the passing direction of the metal plate, and removing the water that has fallen onto the metal plate to the outside of the surface of the metal plate, In the first step, the airflow from the plurality of first fans is blown so as not to concentrate at the center in the width direction of the metal plate, A method for removing water from a metal plate during sheet passing, wherein the inclination angle of the airflow from the first fan is set within a range of 5 to 45 degrees from the vertical direction to the upstream side in the sheet passing direction.

7. The airflow from the first blower is blown down across the entire width direction of the metal plate as seen in the sheet passing direction of the metal plate, 7. The method for draining water from a metal plate during passage as described in claim 6, wherein when there are multiple first fans, the central axis of the airflow of each first fan intersects with the metal plate at a position upstream of the widthwise center side in the sheet passage direction of the metal plate relative to the widthwise end side.

8. A method for draining water from a metal plate when it is passed through, as described in claim 6, wherein in the second step, the second blowers are arranged on both sides of the metal plate, and the central axes of the airflows from each second blower are offset when viewed from above to prevent interference between the airflows.

9. 7. The method for draining water from a metal plate during threading according to claim 6, wherein the metal plate is a hot-rolled steel plate, and the metal plate is water-cooled by the water-spraying equipment and then drained.

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