JPH05177242A - Descaling device for hot rolled steel plate - Google Patents

Abstract

(57) [Summary] [Objective] To provide a device for descaling the end surface of a steel sheet. [Structure] A descaling device for hot-rolled steel plates, in which a side guide 7 of a hot-rolling mill is integrally equipped with a high-pressure water jet nozzle 9 oriented toward the steel plate end face. [Effect] Even if the width of the steel sheet changes, descaling can be performed stably and reliably. Further, the opposing side guides block the splash of the jet water.

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 hot rolled steel sheets in a hot rolling line.

[0002]

2. Description of the Related Art In a hot rolling line, a heated rolled material has a primary scale or slag attached to the surface thereof, and a secondary scale is formed on the surface of the rolled material during rolling.

If a hot-rolled steel sheet having scale attached thereto is rolled as it is, it may cause surface flaws on the product due to indentation of the scale. Therefore, in a continuous hot rolling mill, immediately before the rough rolling mill and immediately before the finish rolling mill. A descaling device is installed in the descaling facility to ensure product quality.

The descaling means is 100 to 2
A general method is to fix a header of high-pressure water of 00 kg / cm ² and spray it onto the surface of a steel plate from a nozzle of a descaling device installed. In this case, the scales on the front and back surfaces of the steel sheet were sprayed with high pressure water of 100 to 200 kg / cm ² from a straight nozzle onto the surface of the steel sheet to cause cracks on the surface scale, as disclosed in JP-A-1-278907. After this, it can be descaled by a method such as removing with a low pressure spray.

[0005]

However, it is difficult to completely remove the scale on the end surface of the steel sheet. The reason is that, as shown in FIG. 3, the wide steel plate 3 and the medium width steel plate 2 are also rolled by the same rolling mill, so that the high-pressure water jet nozzle 5 is fixed regardless of the width of the steel plate, and the narrow steel plate is conventionally used. When descaling No. 1, the distance between the high-pressure water jet nozzle 5 and the steel plate 1 becomes long,
This is because the collision pressure becomes small, or it does not hit the target steel plate end surface. As a result, defects due to residual scale were generated on the end faces of the steel sheet, and that part was the cause of reduced yield.

An object of the present invention is to provide a device for descaling the end surface of a steel plate.

[0007]

DISCLOSURE OF THE INVENTION The gist of the present invention is to descale a hot-rolled steel sheet by integrally mounting a high-pressure water jet nozzle directed to the steel sheet end face on a side guide of a hot-rolling mill. It is a device.

[0008]

The present invention is effective for various types of spray nozzles such as a flat spray nozzle and a straight spray nozzle, but the following description will be given based on an example applied to a flat spray nozzle.

FIG. 1 is a plan view of the device configuration of the present invention.

The narrow steel plate 1 is passed by a steel plate transport roll 6 in the direction of the arrow. The position of the steel sheet 1 in the width direction is determined by the side guide 7. In the present invention, the high pressure water nozzle header 8 is incorporated in the side guide 7, and the high pressure water injection nozzles 9 are vertically arranged in a line in the high pressure water nozzle header 8. ing. Then, the high pressure water jet nozzle 9 is used to descale the end surface of the steel sheet. Reference numeral 5 is a conventional high-pressure water jet nozzle.

The scale of the steel sheet is cut at a constant interval by the high-pressure water from the high-pressure water jet nozzle 9 and cracks are generated, which facilitates the scale peeling. The surface scale that is cut at regular intervals and has cracks can be removed by low pressure water spray or the like.

In order to determine the positional relationship between the nozzle and the steel plate, the collision pressure is measured for each distance from the flat spray nozzle having an original pressure of 120 kg / cm ² to the steel plate, and the descaling property at that time is measured to determine the descaling property. Of the scale and the scale of the end surface of the steel sheet. The result is shown in FIG.

The scales on the front and back surfaces of the steel sheet have a collision pressure of 3 kg.
It made removed / cm ² or more pressure, but to eliminate the scale of the steel sheet edge has been found to be required 25 kg / cm ² or more pressures. This is because the scale of the steel plate surface is 1
It is estimated that this is due to the fact that the scale of the steel plate end surface is as thick as 300 μm, while it is between 00 and 200 μm. Therefore, when the original pressure is 120 kg / cm ² , the distance between the nozzle and the steel plate may be 40 cm to remove the scale on the steel plate surface, but the distance between the nozzle and the steel plate is within 10 cm to remove the scale on the steel plate end face. And have to.

According to the present invention, the high pressure water jet nozzle 9 oriented toward the steel plate end face is integrally mounted on the side guide 7, so that the high pressure water jet nozzle 9 is integrated with the side guide 7 even for the narrow steel plate 1. By moving the high-pressure water jet nozzle 9 and the end face of the narrow steel plate 1 at a short and constant distance, the impact pressure at the steel plate end face of the descaled water can be maintained at a necessary value or more, thereby making the steel plate Make sure to remove the scale on the end face.

[0015]

[Example] A descaling test was performed on a steel plate end face under the following conditions using a flat spray nozzle having an original pressure of 300 kg / cm ² . The descaling property was good. Further, the hot-rolled steel sheet was cold-rolled, but no flaw was generated on the end surface of the steel sheet.

Descaling Conditions (a) Nozzle Type: Flat Nozzle (b) Source Pressure: 300 kg / cm ² (c) Distance between Nozzle and Steel Plate: 200 mm (d) Impact Pressure of Water on Steel Plate: 25 kg / cm ² ( E) Plate passing speed: 2.4 m / sec

[0017]

According to the present invention, even if the width of the steel plate changes, the high-pressure water jet nozzle can move together with the side guides to keep the distance between the high-pressure water jet nozzle and the steel plate short and constant.
Descaling can be performed stably and reliably. Further, the opposing side guides shield the sprayed water from scattering, which is advantageous in terms of equipment maintenance.

[Brief description of drawings]

FIG. 1 is a plan view of a device configuration of the present invention.

FIG. 2 is a diagram showing a relationship between an injection distance of a flat spray nozzle having an original pressure of 120 kg / cm ² and a collision pressure.

FIG. 3 is a diagram showing a positional relationship between a conventional spray nozzle and a steel plate.

[Explanation of symbols]

 1 Narrow Steel Plate 2 Medium Steel Plate 3 Wide Steel Plate 4 High Pressure Water Nozzle Header 5 High Pressure Water Jet Nozzle 6 Steel Sheet Transport Roll 7 Side Guide 8 High Pressure Water Nozzle Header 9 High Pressure Water Jet Nozzle

Claims (1)

[Claims] 1. A descaling device for a hot-rolled steel sheet, characterized in that a high-pressure water jet nozzle directed toward the steel sheet end face is integrally mounted on a side guide of the hot-rolling mill.