JPH08215735A - Scale removing equipment in continuous casting and rolling line - Google Patents

Abstract

PURPOSE: To provide the steel sheet of excellent quality by providing a bending roller unit to give cracking to the surface scales behind the cooling zone and a bridle roll 13 to peel the surface scales to surely remove the scale. CONSTITUTION: Scale removing equipment 5a, 5b are arranged behind a rolling mill 3 and a heat treatment furnace 4. Surface scales are cracked by passing the hot steel strip S through a roller unit 12, and each surface of the hot steel strip S is alternately coiled around the following bridle roll 13 to make the cracked scales loose and peeled, or peel and drop the scales by a wire brush roller 15 and store the scales in a scale receiving pan 14. The bending roller unit 12 consists of rollers 12a, 12b on the upper side and a roller 12c on the lower side, an intermediate roller 12c is elevatably held by an elevating equipment 26, and the penetration is set according to the peeled condition of scales to obtain the hot rolled steel strip S of excellent quality free from scales.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a scale removing device in a continuous casting and rolling line, particularly to a surface of a hot strip steel plate in a twin roll continuous casting line or a twin roll continuous casting / rolling line for producing thin cast pieces. The present invention relates to a device for efficiently removing oxide scale.

[0002]

2. Description of the Related Art For example, when a twin-roll continuous casting / rolling line is taken as an example, a hot hot-rolled steel sheet obtained there has a thin plate thickness (1 to 5 mm) and a casting speed is slow, so that scale is generated. Since it is easy to remove and it is difficult to remove it, we adopted an adiabatic seal box structure that does not generate scale as much as possible to prevent oxidation by controlling the atmosphere. Further, as a measure for removing the oxide scale in the twin roll continuous casting / rolling line, as shown in JP-A-61-219448, a brush roll is arranged in front of the rolling mill to remove the surface oxide scale of the steel strip before rolling. Means for mechanical removal have also been proposed.

However, in the twin-roll continuous casting / rolling line, in reality, the sealing at the inlet and outlet sides around the drum roll, rolling mill, pinch roll, and instrumentation equipment is poor, and it is difficult to control the O ₂ concentration. It is difficult to completely prevent the generation of scale, and oxide scale growth is also observed in the heat treatment furnace after the rolling mill.Currently, the wound coil is accompanied by a scale of considerable thickness. is there.
For this reason, it is possible to apply high-pressure descaling (water pressure 7 to 30 MPa), which is used in ordinary hot rolling lines, to scale removal in twin-roll continuous casting / rolling lines, but the mechanical strength of the material due to temperature drop And the deterioration of the toughness, and the high-pressure injection causes the plate to swing, float, vibrate, and the like, possibly impairing the threadability, and thus it is not applicable. Further, the cooling immediately after rolling of the hot band steel sheet, the removal of scale, and the start of the subsequent heat treatment varied depending on the size of the target material, and could not be applied with a fixed cooling device.

[0004]

As described above, in a thin plate continuous casting line such as a twin roll continuous casting / rolling line, it is not possible to prevent the generation of oxide scale, and it is inevitable in the step after winding. However, scale peeling work is required, and scale removing equipment must be installed for that purpose, which reduces work efficiency and productivity.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an oxide scale of a hot strip steel sheet in a twin roll continuous casting line or a twin roll continuous casting / rolling line. The purpose is to easily remove the steel sheet while considering the target temperature for the quality of the steel sheet.

[0006]

The gist of the present invention is as follows. (1) In a device for removing oxide scale formed on the surface of a hot strip steel sheet that has been cast in a thin plate continuous casting facility or rolled after casting, after the cooling zone, bending is applied to the surface layer scale to crack. A scale removing device in a continuous casting and rolling line, which is provided with a bending roller unit for causing the above-mentioned phenomenon, and a bridle roll for separating the surface layer scale subsequently therefrom. (2) The scale removing device according to (1), characterized in that grinding means for peeling and dropping the scale is provided at an outer peripheral position of the winding of the bridle roll. (3) A pinch roll or bridle roll for applying tension is provided in front of the bending roller unit, dimples and water cooling holes are formed on the surface of the bending roller, and a crown is attached to the bending roller. ) Or (2) the scale removing device. (4) A thermometer is installed after the bridle roll to detect the scale removal state by the temperature distribution and spectrum analysis of the hot band steel plate, and to control the pushing amount of the bending roller unit and / or the front and back tension ( The scale removing device according to 1), (2) or (3).

(5) In an apparatus for removing oxide scale formed on the surface of a hot strip steel sheet that has been cast in a thin plate continuous casting facility or rolled after casting, cooling and quenching of the hot strip steel sheet in a cooling zone A plurality of cooling water jet nozzles for pulverizing and removing the scale layer by means of are arranged, and the position of the jet nozzles is adjustable in the longitudinal direction of the strip steel plate and the direction intersecting with this, and the distance between the hot strip steel plate and the nozzle and cooling A scale removing device in a continuous casting and rolling line having a variable length. (6) A thermometer is installed after the injection nozzle to detect the scale removal state by the temperature distribution and spectrum analysis of the hot strip steel plate, and control the height and / or the cooling length of the injection nozzle (5). The scale removing device described.

[0008]

According to the first aspect of the present invention, since the front and back of the hot strip steel sheet are alternately bent and stretched by the bending roll unit, cracks are generated in the oxide scale on the surface layer of the hot strip steel sheet, and the front and back surfaces are alternately alternated by the bridle roll. The scale is peeled off by winding. In particular, the scale peeling at the bridle roll position of claim 2 (for example, a grindstone roll or a brush roll made of SUS) promotes scale peeling.

Further, in claim 3, since tension is applied to the hot strip steel sheet on the entry side of the bending roller unit, a difference in elongation occurs between the scale and the hot strip steel sheet in the bending roller unit, and a crack develops. Further, the cracking scale is almost completely removed by cooling from the water cooling holes of the bending roller itself, dimple processing, or roll crown.

Further, according to claim 4 or 6, the surface state of the hot strip steel sheet after the scale removal is detected and fed back to control the scale removal device to always perform the optimum scale removal. Further, in claim 5, the hot strip steel plate is cooled at the same time as the scale is removed by the injection of the pressure water from the nozzle, and further, the plate speed and the plate thickness gauge are changed depending on the casting / rolling state. Thus, the optimum cooling start / end point or nozzle height can be selected.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1 showing the layout of a twin roll continuous casting / rolling line, 1 is a twin roll (mold) for receiving molten metal, 2
Is a pinch roll for feeding the cast and solidified thin slab S in a suitable tension state, 3 is a rolling mill for rolling the slab, 4 is a furnace for heat treating the slab after rolling, and 6 is provided in front of the shear 7. Pinch roll, 8 is a pinch roll before the coiler, and 9 is a coiler. If two coilers and pinch rolls are installed as shown in the figure, the work can be continued without interruption.

In the above line, the scale removing device, which is the main part of the present invention, is arranged after the heat treatment furnace 4 or after the rolling mill 3, respectively. That is, the scale removing device 5a arranged after the rolling mill 3 has a bending roller type structure or a medium pressure water injection type structure, and the scale removing device 5b arranged after the heat treatment furnace 4 has a medium pressure water injection type structure. Become.

First, as shown in FIG. 2, the bending roller type scale removing device bends the warm strip steel plate S fed through the pinch rolls 11 in the direction of the arrow 3.
Bending roller unit 12 consisting of two bending rollers, two bridle rolls 13 provided behind it, and a grindstone (grinding) roller or a steel wire (SUS) brush roller abutting on the outer peripheral surface of the bridle roll 13 15
And a removing scale pan 14 installed below the bending roller unit and two bridle roll positions. The pinch roll 11 in front of the bending roll unit 12 gives tension to the hot band steel plate, and can be replaced with a bridle roll in some cases.

In the above description, the hot strip steel sheet S is cracked by passing through the bending roller unit 12, and the scale of the surface layer thereof is cracked. Then, both surfaces of the hot strip steel plate are alternately wound by the bridle roll 13 to cause cracking. The contained scale is floated and peeled off, or preferably peeled off using a grindstone (grinding) roller or a steel wire brush roller 15. The scale that has fallen is stored in the scale pan 14 and carried out of the line.

The bending roller unit 12 includes two rollers 12a, 12b on the upper side of the hot strip steel plate line as shown in the drawing.
And one roller 12c located in the middle of these and provided on the lower side of the hot strip steel plate line, the intermediate roller 1
As shown in FIG. 3, the upper and lower rollers 12a and 12c are held by the lifting device 26 so that they can be moved up and down.
The amount of pushing can be adjusted with respect to b, and the amount of pushing can be appropriately set according to the scale removal state of the hot band steel sheet. FIG.
In the figure, 25 is a bending roller driving device, 27 is a water supply / drainage hole provided from one end side of the drive shaft in the hollow bending roller, and 28 is provided on the roller surface so that the supplied cooling water is discharged from the roller surface. A water cooling hole, 30 is a bearing.

A preferred embodiment of each bending roller has a hollow water-cooled structure as shown in FIG. 4 (a).
Dimple processing 29 (one dimple diameter of 1 to 3 mm, depth of 0.3 to 1 mm) is applied to the outermost surface, and water cooling holes 28 are formed so as to penetrate to many surfaces. The supplied cooling water (0.3 to 1.5 MPa) flows out to directly contact the hot strip steel plate. Further, as shown in FIG. 4 (b), each bending roller is provided with an appropriate crown (crown having a roll diameter of 400 to 800 mm and a length of about 1 to 2 mm), and the hot band steel sheet is subjected to a difference in elongation between the center and the end. A tension distribution can be generated to facilitate scale removal.

Next, a scale removing device of a medium pressure water (pressure 3 to 5 MPa) injection type provided as a cooling zone after heat treatment will be described with reference to FIG. The figure shows an example of an apparatus in which three pairs of injection nozzle rows oriented in the steel plate traveling direction are arranged with the hot band steel plate S sandwiched therebetween in order to spray pressure water to the hot band steel plate S traveling in the arrow direction. . The pressure water jetting means comprises a medium pressure water header main pipe 17, a header manifold 18 branched from the main pipe 17 in three directions, and a jet nozzle 19 attached to the manifold 18. Of the header manifolds 18 that branch off from the mains 17 in three directions, the universal joints 2 are installed on the manifolds on both sides.
No. 0 is interposed so that the nozzle position can be adjusted along the hot zone steel plate traveling direction, as will be described later. A plurality of nozzles 20 are arranged in the width direction of the hot strip steel plate, or
Alternatively, it is formed in a slit shape extending in the width direction.
A plurality of the medium pressure water injection units are installed depending on the plate speed of the hot strip steel plate and the cooling end temperature.

FIG. 6 shows an example of a concrete adjusting mechanism of the scale removing device. That is, the upper and lower injection units are divided into blocks by sandwiching the hot strip steel plate S, and each block 23
The nozzles a and 23b are connected to the moving actuator 21 in the height direction, and the operation thereof allows the nozzle position to be adjusted in a direction intersecting (orthogonal to) the hot zone steel plate traveling direction. Further, in adjusting the nozzle position along the hot zone steel plate traveling direction, a horizontal movement actuator 22 is connected to the universal joint 20 and at least one of the nozzle positions at both ends is changed by driving the actuator 22 to start cooling. The point or the end point may be adjusted.

An example of actually using the adjusting mechanism of the scale removing device is changing the size of the hot strip steel sheet or changing the running gauge. That is, for example, as shown in FIG. 7, when the cooling patterns of the 5.0 mm thick hot strip steel sheet A and the 3.3 mm thick hot strip steel sheet B are compared, the hot strip steel sheet A has Since it is slow, the temperature rapidly decreases from the cooling start point of about 1000 ° C. and reaches the target temperature of about 600 ° C. at about 6 m, but in the hot strip steel sheet B, the plate speed is fast, so until the target cooling temperature is reached. The cooling length is about 14m. Therefore, a cooling length according to the size is obtained in advance, and a command is issued to the horizontal movement actuator 22 according to the actual size of the hot band steel sheet cast, and the nozzle position is changed so that the set cooling length is achieved. That is, the cooling start point and / or the cooling end point are adjusted.

Further, in the case of changing the gauge of the hot strip steel plate during running, the line speed changes at the same time as the gauge change, but the plate thickness does not change until reaching the scale removing device. The cooling start position and the cooling end position based on the gauge thickness are calculated appropriately and controlled by the actuator 22.

Further, since the characteristics of scale peeling differ depending on the type of hot band steel sheet (SUS, ordinary steel, special steel, etc.), it is necessary to change the nozzle height. For this reason, the jetting nozzle is previously set at a predetermined position by the moving actuator 21 according to the steel type of the hot zone steel plate.

Further, in order to carry out the scale removing work more reliably and efficiently, as shown in FIG. 8, for example, a radiation thermometer 31 is installed after the scale removing device to constantly measure the hot strip steel plate temperature. By measuring the temperature distribution and spectrum analysis of synchrotron radiation, the scale condition (scale remaining,
(Scale thickness, etc.), and accordingly, as shown in FIG. 8B, the moving actuators 21 and / or 22 are driven via the control device 32 and the actuator drive control unit 33, and the nozzle height and cooling are controlled. It is also possible to control the scale removal time as long as necessary. In addition,
In the bending roller type scale removing device shown in FIG. 2 as indicated by 5a in FIG. 8 (a), the optimum pushing amount of the bending roller 12c corresponding to the grasping of the scale condition,
By controlling the tension around the bending roller unit 12, it is possible to always perform stable scale removal.

In the scale removing apparatus of the present invention, it is sufficient to install at least one of the bending roll type and the medium pressure water jet type in the continuous casting / rolling line, but both scale removing apparatuses are installed side by side. The optimum one may be selected depending on the steel type, casting conditions, etc., and both may be used together depending on the case.

[0024]

According to the scale removing apparatus of the present invention described above, the following effects can be expected. According to the first aspect, the scale produced in the continuous casting and rolling line can be reliably peeled and removed after the cooling zone in the line, and a high-quality thin strip steel sheet can be obtained. Also,
According to the second and third aspects, the scale with cracks can be more effectively peeled off. According to claim 4 or 6, the optimum scale removal state is always obtained. According to claim 5, the hot zone steel plate is cooled at the same time as the scale is removed by the injection of the pressure water, and the optimum cooling start is performed even when the plate speed and the plate thickness gauge are changed.
Can be maintained at end point or nozzle height.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a continuous casting / rolling line to which a scale removing device according to the present invention is applied.

FIG. 2 is an explanatory view showing an embodiment of a bending roller type scale removing device according to the present invention.

3 is a cross-sectional view showing a holding structure of an intermediate roller of the bending roller unit shown in FIG. 2 and the roller itself.

FIG. 4 is a view showing a structural example of a single roller that constitutes a bending roller unit.

FIG. 5 is an explanatory view showing an embodiment of a medium pressure water jet type scale removing device according to the present invention.

6 is an explanatory view showing an adjusting mechanism of the injection nozzle unit in FIG.

FIG. 7 is an explanatory diagram showing a change in a cooling pattern due to a difference in thickness of a hot strip steel sheet.

FIG. 8 is an explanatory view showing an example of scale removal control in the present invention and a partial detailed view thereof.

[Explanation of symbols]

 S Hot strip steel plate 1 Twin roll 2,6,8,11,16 Pinch roll 3 Rolling machine 4 Heat treatment furnace 5 Scale remover 7 Shear 9 Coiler 12 Bending roller unit 13 Bridle roll 14 Scale pan 15 Grinding roll 17 Header main pipe 18 Header Branch Pipe 19 Nozzle 20 Universal Joint 21 Header Vertical Movement Actuator 22 Header Horizontal Movement Actuator 23 Injection Block 25 Bending Roller Driving Device 26 Bending Roller Elevating Device 27 Cooling Water Supply Hole 28 Water Cooling Hole 29 Dimple 30 Bearing 31 Radiation Thermometer 32 Control device 33 Actuator drive control unit 34 Jet water splash prevention cover 35 Jet water splash prevention hood

Claims (6)

[Claims] 1. An apparatus for removing oxide scale formed on the surface of a hot strip steel sheet cast in a thin plate continuous casting facility or rolled after casting, wherein bending is applied to the surface scale after the cooling zone. A scale removing device in a continuous casting and rolling line, which is provided with a bending roller unit that causes cracks and then a bridle roll that peels off the surface layer scale. 2. The scale removing apparatus according to claim 1, further comprising grinding means for peeling and dropping the scale at an outer peripheral position of winding of the bridle roll. 3. A tensioning pinch roll or bridle roll is provided in front of the bending roller unit, and dimples and water cooling holes are formed on the surface of the bending roller.
The scale removing device according to claim 1 or 2, wherein the bending roller is provided with a crown. 4. A thermometer is installed after the bridle roll to detect the scale removal state by the temperature distribution and spectral analysis of the hot band steel sheet, and to control the pushing amount and / or the front and back tension of the bending roller unit. Claim 1,
The scale removing device according to 2 or 3. 5. An apparatus for removing oxide scale formed on the surface of a hot strip steel sheet cast or rolled after casting in a thin plate continuous casting facility, by cooling and quenching the hot strip steel sheet in a cooling zone. A plurality of cooling water jet nozzles for crushing and removing the scale layer are arranged, and the position of the jet nozzles is adjustable in the longitudinal direction of the strip steel plate and the direction intersecting with the strip steel plate.
A scale removing device in a continuous casting and rolling line, characterized in that a distance between a hot strip steel plate and a nozzle and a cooling length are variable. 6. A thermometer is installed after the injection nozzle to detect the scale removal state by the temperature distribution and spectrum analysis of the hot band steel sheet, and control the height and / or the cooling length of the injection nozzle. Item 5. A scale removing device according to item 5.