JPH04115863A - Mechanical descaling device for hot steel - Google Patents

Abstract

PURPOSE:To remarkably reduce the steel heat loss at descaling time, to lower the heating temperature by that part and to reduce the oxidation scale loss at the cutback, heating times of a fuel original unit. CONSTITUTION:The scale sticked to the hot steel 14 surface is scratched off by a contact member 20. In this case, a descale support substrate is arranged at the upper and lower parts of a hot steel 14, a lot of elastic bodies 21 are erected toward the hot steel by the support substrate, and a silicon nitride made contact member 20 is provided at the tip of the elastic body 21. Consequently, the hot strength and wear resistance are increased and descaling property is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mechanical descaling device for removing scale on the surface of a steel material before rolling in a hot rolling line or the like using a contact member.

[Conventional technology]

When manufacturing steel plates and shaped steel by hot rolling, oxidized scale is attached to the surface of the steel piece after it leaves the heating furnace, and this scale must be removed in advance.

Conventionally, this scale has generally been removed by blowing it off with high-pressure water.

When the surface of a high-temperature steel billet is rapidly cooled with high-pressure water, cracks appear in the scale and the scale rises above the steel billet, which is then blown away by a stream of water.

However, depending on the material of the steel billet, it may be difficult to completely remove the scale, and it may be difficult to completely remove the scale using extremely high pressure water (usually
The power required to remove the scale is enormous, such as using a large amount of water (20 Kg/cm" to 200 Kg/cm"), and at the same time, the steel material is also cooled by water, so it is necessary to heat the steel material to a high temperature in advance. The problem was that it didn't.

For this reason, mechanical descaling using a brush roll instead of high-pressure water has been proposed as in JP-A-62-34618 and JP-A-62-296908.

[Problem to be solved by the invention]

However, in the conventional mechanical descaling apparatus for hot steel materials as described above, the heat of the steel material softens the metal brushes, resulting in significant wear.
Even if you move the brush roll from side to side as in No. 18 to even out the wear, the life will only be slightly extended, and you will need to change the brush roll frequently, which increases the trouble and effort of replacing the brush roll. Economic effects such as consumption costs were low.

Furthermore, as disclosed in JP-A No. 62-296908, although quenching the surface of the steel material immediately before the flagi roll is effective in extending the life of the flagi roll, the life of the brush roll is still short, and the temperature of the steel material decreases due to the rapid cooling. Otherwise, it would be as bad thermoeconomically as the conventional high-pressure water tester.

There were some issues like that.

An object of the present invention is to provide a mechanical descaling device for hot steel material that solves the above-mentioned problems of the conventional hot steel mechanical descaling device and the conventional high-pressure water telescaling device. .

[Means to solve the problem]

In order to achieve the above object, the present invention has the following configuration. That is, in a mechanical descaling device that uses a contact member to scrape off scale attached to the surface of a hot steel material, descaling support bases are arranged above and below the hot steel material,
A large number of elastic bodies are planted toward the hot steel material from the support base,
A contact member made of silicon nitride is provided at the tip of the elastic body, for example, the upper and lower descaling support bases are rotating shafts,
The rotating brush roll has an elastic metal body having a rod-shaped body made of silicon nitride at the tip attached to the outer periphery of the rotating shaft. A ladder is provided between the upper and lower rotating brush rolls in the direction in which the hot steel material travels for spraying pressure fluid such as water or steam for blowing off scale.

[Effect]

According to the above configuration, silicon nitride rods are used in the part where the liquid is applied directly to the hot steel material, so it has high hot strength and excellent wear resistance, as well as good contact with scale. In addition to being able to take high forces, it also has excellent descaling properties.

Then, in order to appropriately adjust the relative speed between the steel material and the silicon nitride brush, the brush is rotated, for example, in the opposite direction to the conveying direction to make contact with the brush more densely, or You can adjust each time whether it rotates and roughly divides the scale.

As for the specific equipment configuration, rotating brush rolls with implanted silicon nitride brushes are installed in upper and lower pairs in multiple stages (multiple rows in the conveying direction) in the steel material conveyance path, and the hot steel material is transferred between the upper and lower rotating brush rolls. A fluid jet header is installed on the moving direction side to blow away the floating scale. Since this fluid jet only blows away the scale on the top surface of the steel material (cracked and floating due to the brush), lower pressure water is sufficient compared to conventional descaling water for quenching purposes, and depending on the scale properties, High-pressure steam or pressurized air may also be used.

Although the brush roll has a rod-shaped body made of heat-resistant silicon nitride at the tip, the holding part uses a steel spring material, so the inside of the rotating support base has a water-cooled structure. Is it necessary to do so? Furthermore, if internal water cooling alone is insufficient for heat resistance, a mist spray (mixture of water and air) device or the like may be provided above the brush roll to cool the bluff portion.

Of course, if the conveyance speed is sufficiently high, a plate-shaped supporting base in which the brush of the present invention is embedded is placed below the steel material conveying path, the supporting base is fixed, and the steel material is passed between them. A descaling effect can be expected.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a front view of a steel piece being descaled using the mechanical chart scaling device of the present invention. When the steel billet 14 passes between the plan rolls 2 arranged above and below,
The brush roll 2 is rotated by a drive motor 13 to scrape off scale that has adhered to the upper and lower surfaces of the brush roll 2.

The upper blank roll 2 can be moved up and down along the guide post 17 with its bearing 3, and the opening/throat 18a can be moved up and down from the cylinder 18 provided at the upper part of the upper separator 16 depending on the thickness of the steel piece 14. The position and pressure are adjusted through. Further, a mist nodder 15 is provided for cooling the brush roll 2.

FIG. 2 shows the arrangement of rolling equipment using the brush roll 2 described above. After the steel slab 14 is heated to a predetermined temperature in a heating furnace (0, not shown), it is advanced by a conveyor roll 1 in the direction of the arrow, and scales on the surface are removed by a brush roll 2 and a pressure fluid injection header 4. , rolling roll 11
Rolling is done by In the illustrated example, three rows of brush rolls 2 are provided, and each brush roll 2 is rotated in a direction opposite to the direction in which the steel billet 14 advances. In addition, the rotation speed and pressure are changed from the inlet side to the outlet side.For example, by increasing the pressure force on the inlet side and lowering the rotation speed, and by lowering the pressure force and increasing the rotation speed on the exit side, the scale removal rate can be improved. Increase the steel billet 1
4. Minimize surface flaws.

In addition, if the number of brush rolls 2 is increased, more complete descaling can be expected.

As shown in FIGS. 3 and 4, the brush roll 2 has a structure in which a hollow tubular intermediate body 23 is attached to the shafts 24 and 25 for the left and right attachments, and a hollow tubular intermediate body 23 is attached to the center of the shaft 25 for attachment on one side. A hollow section 26 for supplying and discharging cooling water is provided in the housing. Then, an elastic metal body 21 having a rod-shaped body 20 made of silicon nitride at the tip is attached to the outer periphery of the intermediate body 23 using a material (channel).
It is planted by 22. The channel 22 and the elastic metal body 21 are preferably fixed with bolts, rivets, etc., respectively.

The rod-shaped body 20 and the elastic metal body 21 are bonded by solidifying the metal body while sintering silicon nitride, or by solidifying the metal body while sintering silicon nitride.
A fitting hole with a step is provided inside, and after shaping and sintering, a cut is made at the tip of the metal body so that it opens in the shape of a hook, and the metal body is inserted into the fitting hole and fixed.

When the brush roll 2 comes into contact with the steel piece 14, the elastic metal body 21
The rod-shaped body 20 made of silicon nitride is bent so that excessive force is not applied to the rod-shaped body 20 made of silicon nitride, and when it is separated from the steel piece, it works by splashing off scale (acting) to improve descaling performance. When the metal body 21 is installed in a spiral manner around the roll periphery, contact with the steel piece is made continuously,
Rotation can be performed smoothly.

Next, experimental results using the test device will be explained.

The brush roll mentioned above has an outer diameter of 600φ, making it 1180 mm.
An intermittent descaling experiment was conducted on ordinary carbon steel pieces heated to 'C, and the wear status of the brushes and the descaling status were confirmed. The pressure of the brush roll is 20 per width of the steel strip.
Kg/cm2, brush roll peripheral speed 5 m/see
(160 rpm), 8 seconds of contact and 7 seconds of rest were repeated. As a result, the wear rate of the tip of the brush is as shown in Figure 5, and compared to the brush made of 5US304 under the same conditions, the wear rate is about 1/3 or less, and the converted telescaling length (
It was estimated that the replacement life could be approximately four times longer depending on the total length of the steel slab.

As shown in Figure 6, this is due to the strength at high temperatures (tensile and bending), or 5tlS304 at 500"C to 600°
Silicon nitride's strength (flexural strength) does not change even up to 1000°C or higher, whereas silicon nitride's strength (tensile strength) decreases rapidly at temperatures above 1000°C. Silicon nitride is extremely superior in terms of wear resistance in the parts that come in contact with hot steel materials. That's the reason.

As mentioned above, the brush roll 2 has silicon nitride on its tip, which has high high-temperature strength, so there is very little wear even when it comes into contact with high-temperature steel. Preferably, cooling is performed immediately thereafter. Specifically, a mist head 15 is provided near the brush roll 2 to spray a mixture of water and compressed air to cool the tip of the plan in particular.

Semi-molten scale may adhere to the tip of the brush, but this cooling solidifies the scale and easily peels it off. On the other hand, a pressure fluid injection header 4 is installed facing the steel billet 14 between the upper and lower rotating brush rolls 2.2 in the direction in which the hot steel material is traveling, and it injects low-pressure water, steam, compressed air, etc. , blow away the scale remaining on the steel piece 14. It is preferable that the header 4 sprays the scale obliquely or in the width direction of the steel piece 14, for example, to quickly remove scale from the top of the steel piece.

〔Effect of the invention〕

The present invention uses a mechanical descaling device that removes scale from the surface of steel using an elastic body with a contact member made of silicon nitride at its tip. By significantly reducing loss and lowering the heating temperature, it is possible to reduce fuel consumption, reduce oxidation scale loss during heating, and improve steel material quality (material that matches the maximum heating temperature).

■In addition to significantly reducing the power required for descaling,
Special equipment for generating high-pressure water is not required, and the capacity of water treatment equipment can be reduced.

In addition, compared to conventionally proposed metal brush rolls, the lifespan of the brush roll can be significantly extended, and the labor required for replacement, replacement parts, and maintenance of replacement brushes can be reduced.

■Since an elastic body is used for the silicon nitride support, excessive loads and impact forces can be prevented, and breakage of the silicon nitride can be prevented.

It has excellent effects such as, and by combining it with pressure fluid injection, it is possible to efficiently remove scale from the surface of steel materials.

[Brief explanation of drawings]

Fig. 1 is a front view illustrating descaling by the device of the present invention, Fig. 2 is an arrangement diagram of a mechanical descaling device using the plan roll of the present invention, Fig. 3 is an assembled diagram of the brush roll of the present invention, and Fig. 4 is A cross-sectional view thereof, FIG. 5 shows the results of a brush abrasion experiment between stainless steel and silicon nitride, and FIG. 6 shows the hot strength between stainless steel and silicon nitride. DESCRIPTION OF SYMBOLS 1...Transportation roll, 2...Brush roll, 3...Bearing, 4...Fluid injection header, 11...Rolling roll, 13 ... Drive motor, 14 ... Steel piece, 15 ... Mist header, 16 ... Upper separator, 17 ...
...Guide post, 18...Cylinder 1
8... Rod, 20... Rod-shaped body, 21
......Elastic metal body, 22...Mounting material (channel), 23...Intermediate body, 24.25
...Mounting is on the shaft, 26...Hollow part.

Claims (2)

[Claims] (1) In a mechanical descaling device that uses a contact member to scrape off scale attached to the surface of hot steel materials,
A descaling support base is disposed above and below the hot steel material, a number of elastic bodies are planted from the support base toward the hot steel material, and a contact member made of silicon nitride is provided at the tip of the elastic body. Mechanical descaling equipment for hot steel materials. (2) The upper and lower descaling support bases of the mechanical descaling device for hot steel materials according to claim 1 are used as rotating shafts, and an elastic metal body having a rod-shaped body made of silicon nitride at the tip is implanted on the outer periphery of the rotating shaft. A mechanical descaling device for hot steel material, characterized in that a rotating brush roll is provided, and a pressure fluid injection header is provided between the upper and lower rotating brush rolls in the direction in which the hot steel material travels.