JPH07178439A - Descaling equipment - Google Patents

Abstract

PURPOSE:To suppress the temp. drop of a material to be rolled and to make the temp. drop at both side ends uniform in the descaling equipment for hot rolling mill with using high pressure water. CONSTITUTION:An offset angle of a descaling nozzle 22 positioned on center line is made zero. The injecting directions of descaling nozzles 22, 22 positioned at both sides thereof are inclined to both sides symmetrically. The bending of the material 30 to be rolled and the unevenness of plate thickness of both ends are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a descaling device for a hot rolling mill arranged in a hot rolling line, and more particularly to a descaling device using high pressure water.

[0002]

2. Description of the Related Art Conventionally, the surface of a material to be rolled is descaled by high-pressure water in a line before hot rolling. A general configuration of the descaling device is shown in FIG.

The descaling device 20 installed on the entrance side of the rolling mill 10 has a pair of upper and lower descaling headers 21 and 21 provided with a pass line of the material 30 to be rolled in between. Each descaling header 21 is at a right angle to the pass line, and a large number of descaling nozzles 22 are attached at intervals in the longitudinal direction.

A large number of descaling nozzles 22 facing the surface of the material 30 to be rolled usually have a jetting direction slightly inclined to the opposite rolling mill side (upstream side) with respect to a line perpendicular to the surface of the material 30 to be rolled. In addition, in order to quickly discharge the high-pressure water jetted to the surface of the material to be rolled 30, especially the upper surface, from the plate surface, α (10 to 20
The jetting direction is offset by an inclination angle of (°) (for example, actual Kaihei 4-75602).

[0005]

In such a descaling device, due to the offset of the nozzle, all the descaling water jetted onto the material to be rolled 30 flows to one side. Therefore, the temperature distribution of the rolled material 30 in the plate width direction becomes non-uniform, and the temperature of the rolled material 30 significantly decreases.

For example, when the offset with respect to the line center is set on the work side as shown in FIG. 1B, all the descaling water jetted onto the material 30 to be rolled is on the work side. The work side becomes colder than the drive side. As a result, there occurs such an adverse effect that the material 30 to be rolled is bent during the hot rolling or the plate thickness distribution in the plate width direction becomes uneven.

Further, the descaling water jetted from the descaling nozzle 22 on the drive side crosses the entire width of the material to be rolled 30 obliquely and has a long flow distance on the material to be rolled 30. Therefore, the temperature of the material 30 to be rolled is remarkably lowered, which causes adverse effects such as roll surface roughness.

It is an object of the present invention to provide a descaling device capable of eliminating these adverse effects without degrading the descaling performance or complicating the configuration.

[0009]

The descaling apparatus of the present invention is a descaling apparatus for hot rolling mills using high-pressure water, in which the tip is directed to the surface of the material to be rolled which moves in the rolling line and the line of the rolling line. Of the many descaling nozzles arranged at intervals in the horizontal direction perpendicular to the center, the nozzles located above the line center have an offset angle of almost 0 with respect to the line center, and the other nozzles have the line center. It is characterized in that the ejection direction is symmetrically inclined to both sides.

[0010]

[Function] Since a large number of nozzles arranged at intervals in the horizontal direction at right angles to the line center of the rolling line are inclined symmetrically with respect to the line center on both sides, they are ejected from the nozzle. The descaling water is evenly distributed on both sides of the rolled material. Therefore, the temperature drop on both sides of the rolled material becomes uniform. Further, the flow distance of the descaling water on the material to be rolled is shortened as a whole, and the temperature decrease of the material to be rolled is suppressed. Furthermore, since the offset angle with respect to the line center for the nozzles located on the line center is set to almost 0, no blind spot occurs in the central portion of the material to be rolled.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view showing the offset of the descaling nozzle in an example of the descaling device embodying the present invention.

Of the many descaling nozzles 22 attached to the descaling header 21, the central descaling nozzle 22 located on the line center.
_O has 0 offset angle to the line center
It is said that.

All of the descaling nozzles 22 _W on the work side of the line center are inclined toward the work side in the direction of the ejection center with the same offset angle α _W. Further, the descaling nozzles 22 _D on the drive side side are inclined toward the drive side at the same offset angle α _D in the ejection center direction.

The work side offset angle α _W and the drive ride side offset angle α _D
Are equal and are selected, for example, from 10 to 30 °. If the offset angles α _W and α _D are small, the descaling capability is insufficient, and conversely, if the offset angles are too large, the temperature of the material to be rolled 30 drops.

Other configurations are the same as those of the conventional descaling apparatus shown in FIG. 1. For example, the inclination angle of the material 30 to be rolled with respect to a line perpendicular to the plate surface is 10 to 2 to the side opposite to the rolling mill (upstream side).
It is set to 0 °.

In the descaling device having such a configuration, all the descaling water jetted from the work-side-side descaling nozzle 22 _W onto the material 30 to be rolled flows to the work-side side and from the material 30 to be rolled. Is discharged. On the other hand, the descaling nozzle 2 on the drive side
The descaling water jetted from the _2D onto the rolled material 30 all flows to the drive side and is discharged from the rolled material 30. Also, the central descaling nozzle 22 _O
The descaling water ejected from the above flows upstream on the central portion of the material 30 to be rolled.

As a result, equal amounts of descaling water are supplied to both sides of the material to be rolled 30, and both sides are symmetrically cooled. Therefore, bending of the material to be rolled 30 during hot rolling is prevented, and the plate thicknesses on both sides become uniform.

Descaling nozzles 22 _W , 22 on both sides
_The descaling water ejected from _D , even if ejected from the nozzle closest to the center, is discharged from above the rolled material 30 only by diagonally crossing half the plate width of the rolled material 30. Further, the descaling water ejected from the central descaling nozzle 22 _O flows upstream on the central portion of the material to be rolled 30, but the amount of water is significantly smaller than the total amount of descaling water. Therefore, rolled material 3
The flow distance of the descaling water on 0 is shortened as a whole, and the temperature drop of the material 30 to be rolled is suppressed.

Also, the central descaling nozzle 22 _O
The central part is descaled like other parts by the descaling water spouted from.

The effect of this embodiment was confirmed using a descaling device on the side of the actual horizontal rolling mill of the rough roll of the hot rolling line. Table 1 shows rolling conditions and descaling conditions.

[0021]

[Table 1]

The descaling water jetted onto the rolled material was evenly distributed to both sides of the rolled material as intended. In the conventional device in which all nozzles are inclined to one side, the descaling water is 10 to 1 upstream from the nozzle directly below the nozzle on the material to be rolled.
Although a large amount flowed over the range of 2 m, the flow distance was shortened to 4 to 5 m in this example. As a result, the temperature difference between the two sides of the rolled material after descaling is 30 to 40 ° C. at the position of 50 mm from the edge compared to the conventional 30 to 40 ° C.
The temperature drop of the entire rolled material due to descaling was suppressed to the following level, and the conventional temperature reduction was improved from about 15 ° to about 5 ° C.

In the above embodiment, the central nozzle having an offset angle of 0 is one, but it may be two or more. Further, the offset angle does not need to be completely zero. However, if the number of nozzles is increased, the temperature drop in the central portion of the material to be rolled 30 becomes large, so 1 to 3 is actually desirable.

Further, the offset aggregations α _W , α on both sides
_D is the same for each nozzle, but if symmetry is ensured on both sides, it is also possible to gradually change (for example, increase) the offset angle as it moves away from the center.

[0025]

As described above, in the descaling device of the present invention, the ejection directions of the descaling nozzles arranged on both sides of the line center are symmetrically inclined to both sides, so that Since the temperature drop in the parts is made uniform, it is possible to prevent material bending during hot rolling and uneven plate thickness on both sides. Further, since the flow distance of the descaling water on the material to be rolled becomes short, it is possible to suppress the temperature decrease of the material to be rolled. Furthermore, since these are achieved by changing the ejection direction of the descaling water, the descaling performance is not deteriorated and the configuration is not complicated, and the practicability is extremely high.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a general configuration of a descaling device using high-pressure water.

FIG. 2 is a plan view showing an offset of a nozzle of an example of a descaling device embodying the present invention.

[Explanation of symbols]

10 Hot Rolling Mill 20 Descaling Device 21 Descaling Header 22 _, 22 _O, 22 _W , 22 _D Descaling Nozzle 30 Rolled Material α, α _W , α _D Offset Angle

Claims (1)

[Claims] 1. In a descaling device for a hot rolling mill using high-pressure water, the tip is directed to the surface of a material to be rolled moving on a rolling line and arranged at intervals in the horizontal direction perpendicular to the line center of the rolling line. Among the numerous descaling nozzles, the nozzles located above the line center have an offset angle of almost 0 with respect to the line center, and the other nozzles have their ejection directions symmetrically inclined to both sides with respect to the line center. Descaling device characterized by