JP3603840B2 - Descaling method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a descaling method in a hot rolling line.
[0002]
[Prior art]
In hot rolling of steel or the like, an oxide film is formed on the surface of the material to be rolled between rolling passes. If this is left untreated, the rolling will proceed, causing oxides to form on the product surface and produce surface defects. In order to prevent this, it is necessary to perform so-called descaling for removing scale between rolling passes.
[0003]
2. Description of the Related Art A descaling apparatus that removes 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 the steel plate.
[0004]
Maintaining a state in which high-pressure water is jetted from each nozzle of the descaling header uniformly without disturbance is not only to maintain descaling performance and maintain good surface quality of products, but also to reduce unevenness in temperature of steel materials. It is extremely important to prevent and maintain good material and dimensional accuracy.
[0005]
The descaling device is arranged so as to spray high-pressure water of 100 to 300 kg / cm2 at a distance of 200 to 300 mm from the surface of the steel material. Further, 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.
[0006]
When the descaling device is not used, if there is no water in the descaling device, the temperature of the steel sheet is about 1000 ° C in the hot rolling line. The nozzle bends and breaks. 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.
[0007]
Therefore, as a technique for solving the above-mentioned problem, for example, Japanese Utility Model Laid-Open No. 54-4222 discloses a technique in which a movable gutter for shutting off bypass water is provided near a descaling device. Japanese Utility Model Laid-Open Publication No. Sho 60-66611 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 a 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]
A conventional technique provided with the above-described blocking mechanism will be described with reference to FIGS.
[0009]
As shown in FIG. 2, when the descaling device is used, high-pressure water 25 is sprayed from the descaling header 12 through the descaling nozzle 24 onto the steel plate 18. On the other hand, when the descaling device is not used, the movable gutter 20 is moved in front of the descaling nozzle 24 as shown in FIG. It is shut off so as not to be.
[0010]
When the supply of high-pressure water is stopped without using a bypass water cutoff device such as a movable gutter 20, if the descaling is not used for a long time, the nozzle tip may be damaged by radiant heat from a high-temperature steel plate. There is.
[0011]
[Problems to be solved by the invention]
The surroundings of the steel sheet conveyed through the hot rolling line are poor in atmosphere for providing a movable bypass water shut-off device due to the large amount of water, steam, and the like. If the device is installed, the reliability of the movable bypass water cut-off device will be reduced, and it will tend to break down. 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 trouble of poor quality. Further, as shown in FIG. 4, may bypass water cut-off device such as a trough 20 on the anti Riniyotte movable steel 18 is damaged, there is a problem that spend effort costs for maintenance.
[0012]
In view of the above circumstances, the present invention aims to (1) prevent the nozzle tip from being damaged by radiant heat from the steel sheet, and (2) eliminate the poor quality of the steel sheet caused by the bypass water falling onto the leaking steel sheet. Provide the desired descaling method.
[0013]
[Means for Solving the Problems]
The present invention hit the pause injection of high pressure water, rotate the descaling header about the axis, a descaling method for directing the nozzle counter-steel side, the descaling header, high-pressure descaling A descaling method characterized by having a double-pipe structure including an inner pipe into which water enters and an outer pipe through which a liquid for cooling the inner pipe flows .
[0014]
[Action]
When descaling is not used, if the descaling header is set so that the nozzle faces the opposite side to 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 nozzle rotates and the nozzle faces away from the steel plate, the tube has a double tube structure and a fluid flows to the outer tube It may be.
[0015]
【Example】
FIG. 1 shows an embodiment of the present invention.
[0016]
A nozzle 24 is mounted on the descaling header 12 mounted about 400 mm above the transport table. A turning arm 50 is attached outside the line of the descaling header 12. The tip of the turning arm 50 is fixed to a rod of a hydraulic cylinder 54 via a pin 52. Further, the hydraulic cylinder 54 is rotatably fixed to a fixing part (not shown) by a clevis pin 56.
[0017]
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. In addition, a swivel joint 66 that enables rotation between the descaling header 12 and the fixed pipe 64 is incorporated.
[0018]
With these mechanisms, the descaling header 12 can rotate about the axis by the operation of the cylinder 54. A similar drive mechanism is attached to each of the descaling headers 12a, 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.
[0019]
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 plate does not deteriorate.
[0020]
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. The descaling header 12 includes an inner tube 16 and an outer tube 14. High pressure water for descaling enters the inner tube 16.
[0021]
The nozzle 24 is attached to a take-out portion from the inner tube 16 and is fixed with a cap nut 26. Further, between the inner pipe 16 and the outer pipe 14, low-pressure water is supplied and discharged.
[0022]
【The invention's effect】
As described above, according to the descaling method of the present invention, since the descaling header is rotated, the nozzle is not cooled. 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 mounting part 24 Descaling nozzle 40 Steel plate 50 Turning arm 52 Pin 54 Hydraulic cylinder 56 Clevis pin 60 Table roller 62 Support structure 64 Fixed piping 66 Swivel joint

Claims (1)

Hit the pause injection of high pressure water, de-rotate the scaled header about the axis, a descaling method for directing the nozzle counter-steel side, the descaling header, inner tube high pressure water for descaling enters A descaling method having a double-pipe structure including an outer pipe through which a liquid for cooling the inner pipe flows .

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