KR100489243B1 - Apparatus and method for cleaning casting roll - Google Patents

Abstract

The present invention relates to a roll washing apparatus and a method of a twin roll sheet caster, the object of which is to prevent foreign matter from adhering to the roll end face and the roll surface of the casting roll to form a molten steel solidification cell during casting. This is to prevent the surface defects of the cast steel from occurring.

Therefore, in order to achieve the above object, the present invention is installed so as to move forward and backward spaced apart by a predetermined interval (H) above the surface of the casting roll (1), formed with a constant diameter (D) to inert gas of a constant pressure A plurality of first gas injection means 20 spraying the surface of the roll to remove foreign substances on the surface of the roll, and spaced apart from the end face 8 of the casting roll 1 by a predetermined interval H; The second gas is installed to be inclined at a predetermined angle (θ) in the longitudinal direction of the end face 8 to be installed to spray an inert gas of a constant pressure with a constant diameter (D) to remove foreign matter attached to the roll end face (8). Provided is a roll washing apparatus for a twin roll sheet caster having an injection means (30).

Description

Roll cleaning device for twin roll sheet casting machine and its method {APPARATUS AND METHOD FOR CLEANING CASTING ROLL}

The present invention relates to a twin roll type sheet casting machine for casting a molten metal into a casting roll that rotates in opposite directions to each other to rapidly solidify while releasing heat of the metal into the casting roll. By spraying a high pressure inert gas on the roll surface as a gas spray nozzle, it prevents foreign matter from adhering to the roll end face of the casting roll and the surface of the roll, so that the surface defects of the local cast when forming the molten steel solidification cell during the casting operation The present invention relates to a roll washing apparatus and a method of a twin roll sheet casting machine so as to prevent the occurrence thereof.

In general, in the casting method of thin plate, the slab is manufactured by continuous casting method through molten steel, the continuous casting method of manufacturing it into thin plate through rolling and finishing operations, and the roll is directly added to the rotating twin roll. There is a twin-roll type sheet casting method for directly manufacturing a sheet without rolling and imaginary slabs through the slab. The latter can manufacture the sheet directly without going through a number of processes of continuous casting method, which leads to considerable cost reduction and process in terms of cost. There has been a lot of research on the twin roll sheet metal casting method.

In the twin roll type sheet casting machine, the conventional roll washing method is attached to the roll surface of the casting roll 1 which rotates into the molten metal pool 4 through the edge dam 7 as shown in FIG. In order to remove the foreign matter, the brush roll 11 which is in close contact with the surface of the casting roll 1 and can be cleaned at an appropriate position outside the casting roll 1, which is a casting roll ( The bristle 12 in contact with the surface of 1) rotated the brush roll 11 provided on the surface at an appropriate speed to remove foreign substances adhering to the surface of the casting roll 1.

That is, the brush roll 11 is used to remove the oxide film or impurities adsorbed on the surface of the casting roll 1 during sheet casting. The brush roll 11 in the conventional casting machine is a casting roll 1 (C) removes impurities on the surface of the casting roll (1) by contacting and rotating the surface of the casting roll (1), but it is easy to generate polishing lines in the circumferential direction on the surface of the casting roll (1). ), The contact state between the two parts is poor, resulting in a non-uniform coagulation cell 9, and of course, a major cause of cracking in the slab 30.

On the other hand, in order to prevent the surface cracks of the cast slag by the brush roll 11 as described above, the brush roll 11 is periodically vibrated to generate a polishing line in the circumferential direction of the casting roll (1) The suppressing structure is disclosed in Japanese Patent Laid-Open No. 09-174203.

That is, the circumferential speed difference between the brush roll 11 and the casting roll 1 used to facilitate the oxide suppression and foreign matter desorption generated on the casting roll 1 surface is maintained at 50 to 300 m / min. .

However, also in the cleaning method of the casting roll as described above, before the casting roll 1, in which the foreign substances desorbed from the casting roll 1 surface, enters the meniscus shield 13, is again adsorbed onto the surface of the roll 1. In the end, the adsorbed foreign matter is no longer able to be removed, and thus, the clean surface of the complete casting roll 1 becomes difficult, causing uneven molten steel solidification cells 9 to be formed during sheet casting. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The object of the present invention is to inject a roll end face of a casting roll and a roll end face of a casting roll by injecting a high pressure inert gas as a gas spray nozzle onto the roll surface. And a roll washing apparatus of a twin roll sheet caster which prevents foreign matter from adhering to the surface of a roll and prevents surface defects of a local cast when forming a molten steel solidification cell during casting. Is in.

As a technical configuration for achieving the above object, the present invention is a twin-roll thin plate casting machine in which the injected molten steel is solidified through a casting roll that rotates with each other and cast into a cast steel, spaced apart a predetermined distance above the surface of the casting roll A plurality of first gas injection means arranged in a lower portion of the head to be moved back and forth, the plurality of first gas injection means being formed with a constant diameter and injecting an inert gas of a predetermined pressure to the roll surface to remove foreign substances on the roll surface; And spaced apart from the end face at predetermined intervals on a head disposed adjacent to the end face of the casting roll, and inclined at an angle of 10-30 ° in the longitudinal direction of the roll end face and attached to the end face. It is configured to remove the foreign matter, the second gas injection means is formed to be sprayed to inert gas of a constant pressure while being formed with a constant diameter; by providing a roll washing apparatus of a twin-roll sheet caster comprising a.

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Further, in another aspect of the present invention, in a twin-roll thin plate casting machine in which injected molten steel is solidified through casting rolls that rotate with each other and cast into cast steel, the cylinder is rolled in the roll length direction under the meniscus shield of the rotating casting rolls. The first gas injection nozzle having a diameter of 2-6 mm in the lower part of the head installed to move left and right is sprayed with an inert gas on the roll surface at a pressure of 1 bar or more at a distance of 10-50 mm from the roll surface to remove foreign substances on the roll surface. Remove it,

At a pressure of 1 bar or more in a state spaced at 10-50 mm intervals from the roll end face through a 2-6 mm diameter second gas injection nozzle installed at an angle of 10-30 ° to the head installed adjacent to the end face of the casting roll. The present invention provides a roll cleaning method of a twin roll sheet caster which removes foreign substances from the roll end face by injecting a high pressure inert gas.

Hereinafter, the device configuration of the present invention in detail with reference to the accompanying drawings as follows.

Figure 2 is an overall configuration showing a roll washing apparatus of a twin roll sheet caster according to the present invention, Figure 3 is a front view showing a roll washing apparatus of a twin roll sheet caster of the present invention, Figure 4 is a twin roll type sheet of the present invention It is a top view which shows the roll washing apparatus of a casting machine.

First, as shown in FIG. 1, a thin sheet casting process is performed. The molten steel supplied between the twin roll casting rolls 1 through the outlet 5 of the immersion nozzle 3 attached to the tundish 2 is cast. The molten steel pool 4 surrounded by the roll 1 and the edge dams 7 provided on both sides thereof is formed, and the molten steel in contact with the casting roll 1 loses heat in the direction of the center of the roll 1. While the molten steel solidification cell 9 is formed on the surface of the roll 1, the cast slab 6 formed through the roll lip of the casting roll 1 exits.

At this time, an upper air blocking meniscus shield 13 device for preventing the molten steel 4 from being oxidized by blocking the molten steel from being in contact with the atmosphere is installed on the upper side of the casting roll 10. The device is supplied with an inert gas (15) at high pressure through the connected gas supply line (14) to the molten steel (4) surface so that the top surface is surrounded by the inert gas, that is, maintained in an inert gas atmosphere.

On the other hand, in the thin plate casting as described above, the oxidative scale formed by the contact of the casting roll 1 and the molten steel 4 is adsorbed on the surface of the casting roll (1), the roll end face (8) and the casting roll (1) and The foreign matter worn on the edge dam is attached to the contact of the edge dam 7.

For example, in the case of manufacturing the STS304 cast iron, such an oxide scale is mainly formed of manganese (Mn) oxide, and the oxide scale formed on the surface of the casting roll 1 becomes thicker as the casting proceeds. The density of the oxide scale layer is also increased.

In order to remove such an oxide scale layer, the brush roll 11 is usually installed, but the brush roll 11 is used by the brush roll 11 when brushing the surface of the casting roll 1 and the roll end face 8. (1) When the fine foreign matter desorbed from the surface is scattered locally on the surface of the casting roll 1, the foreign matter removed is attached to the brushed casting roll 1 again. It results in local surface defects.

In addition, scratches generated on the surface of the roll 1 when using the brush roll 11 adversely affect the quality of the cast steel 6, but when scratches occur in the roll end face 8, the edge portion of the cast steel 6 In addition to the reduction in quality, in particular, the contact between the roll end face 8 and the edge dam 7 becomes extremely poor, and in severe cases may cause a large accident such as leakage of molten steel.

As a result, even if the above-described scratch does not occur on the surface of the casting roll 1 and the end face 8 by the brush roll 11, the foreign matter on the roll surface is not completely removed by the brush roll 11,

Therefore, in the present invention, a roll washing apparatus of a twin roll sheet caster which completely removes fine foreign substances attached to the brush after brushing as air additionally is as follows.

As shown in Figs. 2 to 4, the roll washing apparatus according to the present invention has an end face which is in close contact with the edge dam 7 and the first gas injection means 20 for injecting a high pressure noble active gas into the roll surface. The high-pressure gas is injected into (8), and is divided into the second gas injection means (30).

In FIG. 2, the installation positions of the first and second gas injection means 20 and 30 are illustrated, but the gas supply line 14 for injecting the inert gas 15 to prevent atmospheric contact of the molten steel 4 with the hot water surface is provided. ) Is installed on one side of the meniscus shield 13, the first gas spraying means 20 to the upper side of the roll surface, and the second gas spraying means 30 to both sides of the roll edge face (8) Is located.

Next, as shown in FIGS. 3 and 4, each of the gas injection means 20, 30 shows that the first gas injection means 20 has a diameter D of 2-6 mm. It is composed of a nozzle, the high pressure inert gas is injected through this, the first gas injection nozzle 20 is adjacent to the roll surface (1) to maintain a 10-50mm spacing (H) on the surface of the roll (1) A plurality of arrays are mounted on the lower part of the head portion 23 provided to move left and right along the roll surface 1 as the cylinder 21 connected to the end.

At this time, the reason for moving the head 23 to the left and right as the cylinder 21 is that, if the gas injection nozzle 20 is fixedly installed, only a certain portion of the roll surface is continuously sprayed and attached to the roll surface. This is because it is difficult to uniformly remove fine foreign matter, and the cylinder 21 is operated as the solenoid valve 22.

On the other hand, the first gas injection nozzle 20, but will be described in detail in the following embodiments to be installed so as to inject an inert gas at a pressure of 1bar or more, if the gas injection pressure is small to completely remove the foreign matter on the roll surface Because you can't.

In addition, the head 23 is formed in the shape of a square cylinder is filled with a high-pressure gas inside the head 23, although the head 23 is not indicated by a separate reference numeral in the figure, but the gas of the meniscus shield 13 It is also preferable to be connected to the supply line 14 to receive an inert gas.

Next, as shown in FIGS. 3 and 4, the second gas injection means 30 for injecting a high pressure inert gas to the roll end face 8 as described above also has a diameter of 2-6 mm. It is a nozzle, and is installed on the head 23 to maintain a 10-50mm gap (H) in the roll end face (8), similar to the first gas injection nozzle (20), wherein the roll end face (8) is Since the width W1 and the thickness W2 are small, the second gas injection nozzle 30 is fixedly provided.

On the other hand, the second gas injection nozzle 30 is also installed to inject an inert gas at a pressure of 1 bar or more like the first gas injection nozzle 20, and in particular, the second gas injection nozzle 30 is formed on the head 23. Is installed at an angle of 10-30 degrees in the longitudinal direction of the casting roll (1), which will be described in more detail as a table below.

Hereinafter, the embodiment of the present invention will be described in detail.

As shown in Figures 2 to 4, in the case of actual thin casting, as a result of applying the above-mentioned cleaning device for the casting roll 1, that is, the first and second gas spray nozzles 20 and 30, the casting roll 1 The pressure of the gas injected through the nozzles 20 and 30 installed on the upper surface of the surface or the roll end face 8 side was 1.0 bar or more, and it was confirmed that the effect appeared, as shown in Table 1 as follows. .

Gas pressure (bar)        Roll surface and end face cleanliness (%) Remarks 0.3 30 Partially removed dust 0.3 70 Dust removal rate improved, but dust remained locally. 1.0 95 Dust is almost removed 1.5 Over 98 Dust is completely removed

(At this time, cleanliness (%) = (A-B) / A * 100, where A is the residual dust amount (g) at gas pressure 0 bar and B is the residual dust amount (g) under any gas pressure))

Therefore, as shown in Table 1, the injection pressures of the first and second gas injection nozzles 20 and 30 should be 1 bar or more to completely remove foreign substances on the roll surface 1 and the end face 8. You can see.

Next, as described above, the outlet diameter D of the first and second gas injection nozzles 20 and 30 is preferably 2 to 6 mm, preferably 4 mm, and the surface of the roll 1 and the roll end face 8. The distance H between the first and second gas injection nozzles 20 and 30 is preferably 10 to 50 mm, preferably 30 mm.

That is, when maintaining the distance (H) close to within 10mm, the injection of the high-pressure gas is not only easy to remove dust of the local portion on the roll surface 1 and the roll end face 8, but also sometimes in incomplete casting There is a risk of severe damage to the roll end face 8 by the molten steel coming up along the roll end face.

On the contrary, when the gap H is larger than 50 mm, since sufficient foreign matters can be removed when the gas pressure is increased, equipment increase and cost wasted due to unnecessary gas pressure increase, which is not economical.

On the other hand, when the outlet diameter D of each of the gas injection nozzles 20 and 30 is less than 2 mm, the area to be injected is so localized that it is difficult to remove sufficient foreign matters. In other words, economic loss is caused by unnecessary gas pressure increase.

And, as described in Table 1 above, when the gas pressure is 1.0bar or less, rather than removing the foreign matter rather than only localized the turbulent phenomenon of the gas, it is found that the result of attaching more foreign matter on the surface of the roll (1) Could.

On the other hand, as shown in Figure 4, to maintain the installation angle (θ) of the second gas injection nozzle 30 is installed to remove the foreign matter of the roll end face 8, the roll end face ( This is because the foreign matter desorbed by the gas injection nozzle 17 is likely to be reattached to the roll end face 8 and the roll 1 surface while flying in the rotational direction of the roll 1 when it is perpendicular to 8).

As a result, when the second gas injection nozzle 30 is installed at a predetermined angle, it can be seen that the desorbed foreign matter is easily removed by moving in the opposite direction of the meniscus shield 13. The angle θ is 10 to 30 °, Preferably, 20 degrees are the most preferable, and when it is shown as Table 2, it is as follows.

Nozzle Angle (°) Roll Edface Cleanliness (%) Remarks 0-10 70-88 10-20 88-98 Most effective 20-30 88-98 Most effective 30-40 65-88 40-50 65 or less

(At this time, cleanness (%) = (A-B) / A * 100, where A is the amount of residual dust (g) at a nozzle angle of 90 ° and B is the amount of residual dust (g) at any nozzle angle))

As can be seen from Table 2, the cleanliness of the roll interface 8 is the best when the installation angle of the second gas spray nozzle 30 is inclined by about 10-30 ° in the longitudinal direction of the casting roll 1. It can be seen.

Accordingly, by effectively removing the foreign matter adhering to the roll surface 1 and the roll end face 8 during thin plate casting by a twin roll type sheet casting machine, it is possible to prevent local cracking of the slab 6 and to provide a roll end face ( It also prevents scratching due to foreign substances generated between 8) and the edge dam 7 to further improve the quality of cast steel, ie, sheet products.

As described above, according to the roll washing apparatus and method of the twin-roll thin-wall casting machine, the roll end face and the roll surface of the casting roll are sprayed by injecting a high pressure inert gas into the roll end face of the casting roll as a gas spray nozzle. By preventing foreign matter from adhering to the surface, there is an excellent effect of preventing the occurrence of surface defects of the local cast when forming the molten steel solidification cell during casting.

While the invention has been shown and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention as set forth in the claims below. I would like to know that those who have knowledge of this can easily know.

1 is a schematic diagram showing a typical twin roll sheet casting machine

Figure 2 is an overall configuration diagram showing a roll washing apparatus of a twin-roll sheet caster according to the present invention

Figure 3 is a front view showing the roll cleaning device of the present inventors twin-roll sheet caster

Figure 4 is a plan view showing a roll washing apparatus of the inventors twin roll sheet caster

Explanation of symbols on the main parts of the drawings

1 .... casting roll 2 .... tundish

3 .... Immersion nozzle 4 .... Molten pool

5 .... Nozzle outlet 6 .... Strip

7 .... edge dam 8 .... roll endface

9 .... solidified shell 10 .... Chilled water hole

11 .... brush roll 12 .... bristle

13 .... meniscus shield 14 .... gas supply line

20,30 .... 1st, 2nd gas injection nozzle 21 .... Cylinder

22 .... Solenoid Valve 23 .... Head

W1 .... Roll endface protrusion width

W2 .... Roll endface protrusion thickness

H .... Spacing between gas injection nozzle and roll end face

θ .... Installation angle of the second gas injection nozzle

D .... Diameter of gas injection nozzle

Claims (4)

In the twin-roll type sheet casting machine in which the injected molten steel is solidified through the casting roll 1 rotating with each other and cast into the slab 6, A plurality of arrays are mounted on the lower part of the head 23 spaced apart from each other by a predetermined interval (H) above the surface of the casting roll (1), and formed with a constant diameter (D) while inert gas having a constant pressure on the roll surface. A plurality of first gas injection means 20 for spraying to remove foreign substances on the roll surface; And, On the head 23 arranged adjacent to the end face 8 of the casting roll 1 is spaced apart from the end face at a predetermined distance (H), 10- in the longitudinal direction of the roll end face (8) A second gas injection means installed to be inclined at an angle of 30 ° and configured to remove foreign substances attached to the end face 8 and formed to have a constant diameter D so as to spray inert gas of a predetermined pressure ( 30); Roll cleaning device of a twin-roll sheet caster, characterized in that configured to include 2. The gas injector according to claim 1, wherein the first gas injecting means (20) is formed of a spray nozzle having a diameter of 2-6 mm, and the first gas injecting means (20) is formed on the surface of the roll (10). The head 23 is disposed at 50mm interval (H), the first gas injection means 20 is arranged in a plurality of the lower head 23 is provided so that the cylinder 21 is connected to the end to move left and right along the roll surface , The first gas injection means 20 is a roll washing apparatus of a twin-roll type sheet caster, characterized in that configured to spray an inert gas at a pressure of 1 bar or more The method of claim 1, wherein the second gas injection means 30 is formed of a spray nozzle having a diameter of 2-6mm, the second gas injection means 30 is 10-50mm interval (H) from the roll surface It is provided to maintain, the second gas injection means 30 is a roll washing apparatus of a twin-roll type sheet caster, characterized in that configured to spray an inert gas at a pressure of 1 bar or more In the twin roll type sheet casting machine in which the injected molten steel is solidified through the casting roll 1 rotating with each other and cast into the cast steel 6, A diameter (D) of 2-6 mm mounted on a lower portion of the head (23) installed to move left and right as a cylinder (21) in the roll length direction at a lower portion of the meniscus shield (13) of the rotating casting roll (1). 1 Inert gas is sprayed onto the roll surface by a pressure of 1 bar or more through the nozzle 20 in a state spaced apart from the roll surface by 10-50 mm interval (H) through the gas injection nozzle (2) to remove foreign substances on the surface, The roll end face is passed through a second gas spray nozzle 30 having a diameter of 2-6 mm D inclined 10-30 ° on the head 23 provided adjacent to the end face 8 of the casting roll 1. Roll of the twin-roll sheet caster, characterized in that to remove foreign substances in the roll end face 8 by injecting a high pressure inert gas at a pressure of 1 bar or more in a state spaced at an interval (H) of 10-50mm from (8) How to wash