JP2002172416A - Descaling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a descaling method capable of preventing nozzle-tips from being damaged by a radiant heat from a steel plate and simultaneously capable of restraining the generation of deterioration in quality of the steel plate because the bypassing water leaks and drops on to the steel plate. SOLUTION: When a high pressure water spray is suspended, the header is axially rotated and the nozzles are pointed at anti-steel plate side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a descaling method in a hot rolling line.

[0002]

2. Description of the Related Art In hot rolling of steel or the like, an oxide film is formed on the surface of a material to be rolled between rolling passes. If the rolling is carried out while leaving this as it is, the oxide causes a surface defect that is hardly formed on the product surface. In order to prevent this, it is necessary to perform so-called descaling for removing scale between rolling passes.

[0003] A descaling apparatus for removing scale from the surface of a steel sheet by injecting high-pressure water from above the steel sheet is known. Above the hot rolling line, a descaling device and a descaling nozzle attached to the descaling device are always installed, and whether or not to use the descaling device is selected according to the type of steel plate.

[0004] Maintaining a state in which high-pressure water is jetted from each nozzle of the descaling header uniformly and without disturbance is not only for maintaining descaling performance and maintaining good surface quality of the product, but also for improving the quality of the steel material. It is extremely important to prevent temperature unevenness and to maintain good material or dimensional accuracy.

[0005] The descaling device is 200 mm from the steel surface.
100-300 kg / cm2
Of high-pressure water. In addition, the descaling header nozzle deteriorates rapidly because it uses high-pressure water. In order to prevent a decrease in descaling performance due to this, periodic inspection and replacement of the nozzle is required. The descaling device may or may not be used depending on the type of steel.

When not using a descaling device,
If there is no water in the descaling device, the temperature of the steel sheet is about 1000 ° C. in the hot rolling line, and the radiant heat of the steel sheet causes the descaling header and the descaling nozzle to bend and break. In order to prevent such damage to the descaling device, low-pressure bypass water is passed through the descaling device to cool the descaling device. The temperature decreases and the quality of the steel sheet decreases.

Therefore, as a technique for solving the above problem,
For example, Japanese Utility Model Application Laid-Open No. 54-4222 discloses a technique in which a movable gutter for shutting off bypass water is provided near a descaling device. In addition, 60-66611
Japanese Patent Application Laid-Open Publication No. H11-163,086 discloses a technique in which a movable plate for shutting off bypass water is provided near a descaling device. In each of the above-mentioned conventional techniques, bypass water is once passed through the descaling device, and a movable shutoff mechanism is provided so that the bypass water does not fall on the surface of the steel plate.

[0008] The conventional technology provided with the above-mentioned shut-off mechanism is as follows.
This will be described with reference to FIGS.

As shown in FIG. 2, when the descaling device is used, the high-pressure water 25 passes from the descaling header 12 through the descaling nozzle 24 to the steel plate 1.
8 has been injected. On the other hand, when the descaling device is not used, as shown in FIG.
0 is moved forward of the descaling nozzle 24, and the gutter 20 blocks the bypass water from dropping onto the surface of the steel plate 18.

When the supply of high-pressure water is stopped without using a bypass water shutoff device such as a movable gutter 20, if the descaling is not used for a long time, radiant heat is received from a high-temperature steel plate to damage the nozzle tip. There is a problem.

[0011]

The surrounding area of a steel sheet conveyed on a hot rolling line is a place where the atmosphere is poor for providing a movable bypass water cut-off device due to a large amount of water and steam. When a bypass water cutoff device such as a movable gutter is installed, the reliability of the movable bypass water cutoff device is reduced, and a failure tends to occur. If the movable bypass water shut-off device breaks down, there is a problem that bypass water is applied to the surface of the steel plate, resulting in a problem of poor quality. Also, as shown in FIG.
In some cases, the bypass water shut-off device such as 0 may be damaged, and there is a problem that labor costs for maintenance are spent.

In view of the above circumstances, the present invention is intended to (1) prevent the nozzle tip from being damaged by receiving radiant heat from the steel plate, and (2) prevent the steel plate from being defective due to the drop of bypass water onto the leaked steel plate. Provide a descaling method aimed at eliminating it.

[0013]

According to the method of the present invention, when stopping the injection of high-pressure water, the header is rotated around an axis,
This is a descaling method characterized in that the nozzle is directed to the side opposite to the steel plate.

[0014]

When descaling is not used, if the descaling header is set so that the nozzle faces the opposite side of the steel plate, the nozzle tip does not receive radiation from the steel plate, so that there is no damage to the nozzle. In addition, if the nozzle is turned upward by rotating the header, the bypass water does not leak, so that the quality of the steel plate is not deteriorated. Furthermore, in order to prevent damage to the tube itself due to radiant heat acting on the header tube when the header rotates and the nozzle faces away from the steel plate, the tube is made into a double tube structure and the fluid flows to the outer tube It may be.

[0015]

FIG. 1 shows an embodiment of the present invention.

A nozzle 24 is mounted on the descaling header 12 mounted about 400 mm above the transfer table. A turning arm 50 is attached outside the line of the descaling header 12. The tip of the turning arm 50 is connected to the hydraulic cylinder 5 via a pin 52.
4 is fixed to the rod. Further, the hydraulic cylinder 54 is rotatably fixed to a fixing part (not shown) by a clevis pin 56.

FIG. 5 is a front view of FIG. The descaling header 12 is rotatably mounted on a support mechanism 62 mounted on an axle box of the table roller 60.
A swivel joint 6 that enables rotation between the descaling header 12 and the fixed pipe 64 is provided.
6 is incorporated.

By these mechanisms, the descaling header 12 can rotate about the axis by the operation of the cylinder 54. A similar drive mechanism is descaling header 1
2a, 12b, 12c... This drive mechanism may rotate a number of descaling headers simultaneously. An electric motor, pneumatic pressure, or the like can be used as the power.

With such a mechanism, the descaling header is not damaged even if the outer tube 14 receives radiation from the steel plate 40 when the descaling header is not used. Further, if the nozzle is turned upward by rotating the header, the bypass water does not leak, so that the quality of the steel sheet is not deteriorated.

FIG. 6 is a diagram showing a preferred embodiment of the embodiment of the present invention, and is a cross section of the descaling header 12. As shown in FIG.
The descaling header 12 includes an inner tube 16 and an outer tube 14. High pressure water for descaling enters the inner tube 16.

The nozzle 24 is attached to a take-out portion from the inner tube 16 and is fixed by a cap nut 26. Further, between the inner pipe 16 and the outer pipe 14, low-pressure water is supplied and discharged.

[0022]

As described above, according to the descaling method of the present invention, since the descaling header is rotated, the nozzle is not damaged. Moreover, there is no trouble such as the occurrence of poor quality of the steel sheet due to water leakage. Further, when a double pipe structure is used and the switching means is provided in the descaling device, water can be supplied to the outer pipe only when the descaling device is not used, so that the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a descaling device used in an embodiment.

FIG. 2 is a side view showing a state in which descaling water is jetted from a conventional descaling device.

FIG. 3 is a side view showing a bypass water blocking state of the conventional descaling device.

FIG. 4 is a side view showing a state in which a movable gutter is damaged by turning over a steel plate.

FIG. 5 is a front view of FIG. 1;

FIG. 6 is a sectional view of a descaling header.

[Explanation of symbols]

 12, 12a, 12b, 12c Descaling device 14 Outer tube 16 Inner tube 22 Nozzle attachment part 24 Descaling nozzle 40 Steel plate 50 Swivel arm 52 Pin 54 Hydraulic cylinder 56 Clevis pin 60 Table roller 62 Support structure 64 Fixed piping 66 Swivel joint

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshio Imazeki 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Co., Ltd. Inside the Chiba Works (72) Inventor ▲ Yoshi ▼ mura Hiroyuki 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Inside Chiba Works (72) Inventor Toshisada Takechi 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Steel Co., Ltd.

Claims (1)

[Claims] 1. A descaling method characterized by rotating a header around an axis and turning a nozzle toward a non-steel plate side when stopping injection of high-pressure water.