WO2014098490A1

WO2014098490A1 - Hybrid cooling nozzle apparatus, and method for controlling cooling nozzle of continuous casting equipment using same

Info

Publication number: WO2014098490A1
Application number: PCT/KR2013/011854
Authority: WO
Inventors: 황종연; 김성연
Original assignee: (주)포스코
Priority date: 2012-12-21
Filing date: 2013-12-19
Publication date: 2014-06-26
Also published as: CN104884189A; EP2937162A1; CN104884189B; EP2937162A4; EP2937162B1; KR20140081471A; KR101421841B1

Abstract

The present invention relates to a hybrid cooling nozzle apparatus capable of selecting a spray means and spraying a material based on the speed of the strip passing through a segment. The present invention also relates to a method for controlling a cooling nozzle of a continuous casting equipment using the nozzle apparatus. The hybrid cooling nozzle apparatus according to one embodiment of the present invention is a plurality of spray nozzle apparatuses arranged in the segment of the continuous casting equipment, and comprises: a plurality of hybrid nozzles for spraying cooling water in a mist spray means or in a water-cooling means to the strip passing through the segment; one or more speed sensors arranged in the segment to sense the speed of the strip passing through the segment; a cooling water supply unit for supplying cooling water to the plurality of hybrid nozzles; an air supply unit for supplying air to the plurality of hybrid nozzles; and a control unit for receiving the speed of the strip sensed by the speed sensors, selecting the spray means of the hybrid nozzles based on the received speed of the strip, and controlling the cooling water supply unit and the air supply unit so as to control the pressure of the cooling water and flow rate of the air being supplied to the plurality of hybrid nozzles.

Description

Hybrid cooling nozzle device and cooling nozzle control method of continuous casting equipment using the same

The present invention relates to a cooling nozzle device provided in a segment of a continuous casting facility, and more particularly, to a hybrid cooling nozzle device for spraying by selecting an injection method according to the speed of a slab passing through the segment, and cooling of the continuous casting facility using the same. It relates to a nozzle control method.

In general, a continuous casting process is a process of solidifying liquid molten steel into a solid form in a constant form, and a plurality of nozzles provided in a segment are used to cool the cast steel during the continuous casting operation.

1 is a view showing a general continuous casting process.

First, molten steel is injected into the tundish 40 through a long nozzle in the ladle 30, where the molten steel is finished, and the molten steel temporarily stored in the tundish 40 is tundished. 40) and injected into the mold 50 via a molten steel delivery device (DELIVERY SYSTEM) located between the mold (MOLD, 50), the primary cooling in the mold 50, the secondary cooling in the bottom of the mold 50 By solidifying through the process refers to a series of processes for producing cast steel 60, such as billet (BILLET), bloom (BLOOM), slab (SLAB).

MOLTEN STEEL discharged through the mold 50 is the upper frame 22 which is provided on the segment (SEGMENT, 20) of the continuous casting device in the state that the surface is slightly solidified through the primary cooling in the mold 50 and In between the lower frame 23, the cooling water is sprayed through a plurality of nozzles 24 for rapid solidification of the molten steel is continuously changed to the shape of the cast steel to be produced.

2 is a view showing a segment equipped with a nozzle used in a general continuous casting process.

As shown in FIG. 2, the plurality of rolls 21 mounted on the segment 20 are generally composed of an upper roll assembly and a lower roll assembly composed of 5 to 10 rolls 21, and the quick roll of molten steel. A plurality of nozzles 24 for spraying cooling water for solidification are provided.

At this time, if the coolant is not smoothly sprayed from the nozzle 24, the section in which the coolant is not sprayed is caused by the bulging phenomenon of the cast due to the solidification delay, that is, by the ferro-static pressure acting in the width direction. The phenomenon that a cast piece swells between guide rolls arises. This bulging phenomenon causes internal defects or central segregation of the cast steel, and when bulging occurs, the thickened steel in the solidification transition layer is compressed to appear. This segregation has a problem in that a low concentration of molten steel is supplied after the thickened molten steel is compressed, so that defects accompanied with segregation occur, which adversely affects the quality of the final product.

On the other hand, when the coolant is excessively injected from the nozzle 24, or when casting at a low speed in the continuous casting process, a defect such as crack (CRACK) occurs in the corner due to the temperature drop of the slab passing through the segment 20. Defects such as cracks are removed through additional processing because they degrade the surface quality of the cast. This additional process had the problem of incurring additional costs.

For the edge crack prevention method and apparatus of a slab which controls the cooling of the slab during continuous casting by using an air mist spray nozzle to prevent defects such as edge cracks, And 10-2012-0074744).

However, when casting at a high speed in the continuous casting process, it was not able to effectively cool the cast steel passing through the segment to solve the problem of causing a delay in solidification.

In addition, when increasing the water pressure of the cooling water did not solve the problem that the cooling water flows back to the air inlet of the air mist spray nozzle.

The present invention selects the spraying method according to the speed of the slab passing through the segment, and by spraying, the hybrid to prevent cracking in the corner due to the bulging (bulbing) phenomenon of the cast due to the solidification delay of the cast and the supercooling of the cast A cooling nozzle apparatus and a cooling nozzle control method of a continuous casting facility using the same are provided.

In addition, the present invention provides a hybrid cooling nozzle apparatus that increases a turn down ratio by installing a shut off valve to prevent a reverse flow of cooling water in an air line for supplying air to a hybrid nozzle.

Hybrid cooling nozzle device according to an embodiment of the present invention is a plurality of spray nozzle device provided in the segment of the continuous casting facility, a plurality of hybrid nozzle for injecting the cooling water in the mist method or water cooling method to the slab passing through the segment; At least one speed detection sensor installed in the segment to detect the speed of the cast steel passing through the segment; A cooling water supply unit supplying cooling water to a plurality of the hybrid nozzles; An air supply unit supplying air to a plurality of the hybrid nozzles; And receiving the speed of the cast steel detected by the speed detecting sensor, selecting the spraying method of the hybrid nozzle according to the speed of the received cast steel, and controlling the cooling water supply unit and the air supply unit to supply the cooling water to the plurality of hybrid nozzles. It includes a control unit for adjusting the pressure and the flow rate of air.

The coolant supply unit is provided with a coolant line for supplying coolant to the hybrid nozzle and a coolant valve installed in the coolant line to adjust the pressure of the coolant supplied to the hybrid nozzle, and the air supply unit supplies air to the hybrid nozzle. An air valve installed in the air line and the air line to adjust a flow rate of air supplied to the hybrid nozzle; And a shutoff valve for preventing backflow of the coolant, wherein the controller controls the coolant valve and the air valve according to the spraying method of the hybrid nozzle.

The control unit may control to close the plurality of shutoff valves to prevent the cooling water from flowing into the air line when the pressure of the cooling water supplied to the hybrid nozzle is 8 bar or more.

A cooling nozzle control method of a continuous casting facility according to an embodiment of the present invention is a method for controlling a nozzle which is provided in a segment of a continuous casting facility to inject cooling water to a cast steel, the steel grade of the cast steel passing through the segment and Detecting a speed; Selecting the spraying method of the spray nozzle according to the speed of the cast steel; And controlling the flow rate of air and the pressure of the cooling water supplied to the spray nozzle according to the spraying method of the selected nozzle.

The step of selecting the spraying method of the spray nozzle, the spraying method of the nozzle according to the steel type and speed of the cast steel is characterized in that for selecting the mist injection method or water cooling injection method.

Controlling the flow rate of the cooling water supplied to the spray nozzle and the flow rate of the air, in the case of the water cooling injection method, the pressure of the cooling water supplied to the spray nozzle is controlled to 8bar or more, and in the case of the mist injection method to the spray nozzle It is characterized by controlling the pressure of the cooling water supplied to less than 8bar.

According to an embodiment of the present invention, the spraying method is selected and sprayed according to the speed of the slab passing through the segment, thereby preventing cracks in the corners due to the bulging phenomenon of the slab and the overcooling of the slab due to the solidification delay of the slab. can do.

In addition, by preventing cracks in the cast, there is an effect of reducing the additional process and cost for removing the cracks.

In addition, by controlling the pressure of the air and the cooling water in accordance with the speed of the cast steel, there is an effect of preventing the waste of air and cooling water to reduce the cost.

In addition, a turn off valve may be installed in an air line for supplying air to the hybrid nozzle to prevent a back flow of cooling water, thereby increasing a turn down ratio.

1 is a view showing a general continuous casting process,

2 is a view showing a segment equipped with a nozzle used in a typical continuous casting process,

3 is a view showing an installation state of a hybrid cooling nozzle apparatus according to an embodiment of the present invention,

4 is a view showing the pressure relationship between the air and the cooling water according to the injection method of the hybrid nozzle according to an embodiment of the present invention,

5 is a graph showing the cooling performance according to the application of the hybrid nozzle according to an embodiment of the present invention,

6 is a flowchart illustrating a cooling nozzle control method of a continuous casting machine according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the embodiments. For reference, in the present description, the same numbers refer to substantially the same elements, and may be described by referring to the contents described in the other drawings under these rules, and the contents determined to be obvious to those skilled in the art or repeated may be omitted.

3 is a view showing the installation state of the hybrid cooling nozzle apparatus according to an embodiment of the present invention, Figure 4 is a view showing the pressure relationship between the air and the cooling water according to the injection method of the hybrid nozzle according to an embodiment of the present invention. 5 is a graph showing the cooling performance according to the application of the hybrid nozzle according to an embodiment of the present invention.

As shown in the figure, the hybrid cooling nozzle device 10 according to an embodiment of the present invention is installed in the segment 20 of the continuous casting equipment is a mist type or the slab 60 passing through the segment 20 or A plurality of hybrid nozzles 100 for spraying cooling water in a water cooling method; One or more speed detection sensors (200) installed on one side of the segment (20) to detect the speed of the slab (60) passing through the segment (20); A cooling water supply unit 300 supplying cooling water to a plurality of the hybrid nozzles 100; An air supply unit 400 supplying air to a plurality of the hybrid nozzles 100; And receiving the speed of the cast steel 60 from the speed detection sensor 200 to select the injection method of the hybrid nozzle 100, and to adjust the pressure of the cooling water supplied to the hybrid nozzle 100 and the flow rate of air The control unit 500 is included.

The hybrid nozzle 100 cools the slab 60 passing through the segment 20 in a mist method of spraying cooling water and air at the same time, or a water cooling method of spraying only cooling water.

The speed detection sensor 200 detects the speed of the slab 60 passing through the segment 20 and transmits the speed to the control unit 500.

The method for measuring the speed of the cast steel 60 is to measure the speed of the cast steel 60 passing through the segment 20 directly, or the roll 20 provided in the segment 20 to move the cast steel 60 By measuring the rotational speed of the slab 60 can be measured.

In this case, the speed detection sensor 200 may be used, for example, a magnetic sensor, a dacogenerator, a stroboscope type sensor, and the like, and the speed detection sensor 200 is limited to the types of sensors described in the above-described embodiments. Instead, various types of speed sensors capable of detecting the speed of the cast steel 60 or the rotational speed of the roll 21 may be selectively applied.

The cooling water supply unit 300 is installed in the cooling water line 310 to be connected to the hybrid nozzle 100 to supply the cooling water and to control the pressure of the cooling water supplied to the hybrid nozzle 100. The coolant valve 320, wherein the coolant valve 320 is the control unit 500 according to the steel grade of the cast steel 60 and the speed of the cast steel 60 measured by the speed detection sensor 200 Controlled by

In this case, the coolant valve 320 may be used, for example, a relief valve, a pressure reducing valve, a safety valve, and the like, and the coolant valve 320 is not limited to the type of valve described in the above-described embodiment, and the hybrid nozzle Various types of valves capable of adjusting the pressure of the cooling water supplied to the 100 may be selectively applied.

When the injection method of the hybrid nozzle 100 is a mist method, the air supply unit 400 is connected to the hybrid nozzle 100 so that the air is sprayed together with the coolant to spray the coolant in the form of a mist to supply air. 410, a water cooling method in which the air valve 420 installed in the air line 410 and the hybrid nozzle 100 are sprayed only with cooling water to adjust a flow rate of air supplied to the hybrid nozzle 100. In this case, a shutoff valve 430 is installed between the air valve 420 and the hybrid nozzle 100 to prevent the coolant from flowing back to the air line 410 connected to the hybrid nozzle 100. do.

The air valve 420 and the shutoff valve 430 are controlled by the controller 500 according to the steel grade of the cast steel 60 and the speed of the cast steel 60 measured by the speed detection sensor 200.

In this case, the air valve 420 may be used, for example, a relief valve, a pressure reducing valve, a safety valve, and the like, and the air valve 420 is not limited to the type of valve described in the above-described embodiment, and the hybrid nozzle Various types of valves capable of adjusting the flow rate of air supplied to 100 may be selectively applied.

In addition, the shutoff valve 430 blocks the air line 410 when the cooling water injection method of the hybrid nozzle 100 is a water cooling method according to the steel grade of the cast steel 60 and the speed of the cast steel 60. To prevent the coolant from flowing back into the air line 410.

The shutoff valve 430 according to an embodiment of the present invention uses a shutoff valve so that the coolant does not flow back to the air line 410, but the shutoff valve 430 is not limited thereto. Various types of valves, such as a check valve, may be selectively applied and used to prevent the coolant from flowing back to the air line 410.

The shutoff valve 430 when the speed reference value of the cast steel 60 and the cast steel 60 according to the steel grade is input in advance, and the speed of the cast steel 60 is relatively higher than the reference value. ) To close the air line 410, and to spray the coolant in a water-cooled manner to control the coolant valve 320 so that the pressure of the coolant supplied to the hybrid nozzle 100 is 8 ~ 25 bar.

In addition, when the speed of the cast steel 60 is relatively lower than the reference value, the hybrid nozzle 100 is controlled to be sprayed in a mist manner so that the corner crack due to the temperature decrease of the cast steel 60 does not occur. At this time, the control unit 500 opens the shutoff valve 430, controls the air valve 420 so that the flow rate of air supplied to the hybrid nozzle 100 is 0 ~ 15 N ㎥ / hr, The cooling water valve 320 is controlled such that the pressure of the cooling water supplied to the hybrid nozzle 100 is 0 to 8 bar, thereby spraying the cooling water in a mist manner.

The cooling nozzle control method of the continuous casting facility using the hybrid cooling nozzle apparatus 10 according to the embodiment of the present invention configured as described above will be described with reference to the drawings.

As shown in the figure, the cooling nozzle control method of the continuous casting facility using the hybrid cooling nozzle device 10 according to an embodiment of the present invention (steel) of the slab 60 passing through the segment 20 And detecting the speed, selecting an injection method of the hybrid nozzle 100 according to the speed of the slab 60 passing through the segment 20 and the hybrid method according to the injection method of the hybrid nozzle 100. Controlling the pressure of the cooling water supplied to the nozzle 100 and the flow rate of the air.

Detecting the steel grade and speed of the cast steel 60 measures the steel grade of the cast steel 60 introduced into the segment 20 via the mold 50 and the speed of the cast steel 60 in the speed detection sensor 200. To the control unit 500.

In the step of selecting the spraying method of the hybrid nozzle 100, the control unit 500 inputs the speed reference value of the cast steel 60 according to the steel grade and the steel grade of the cast steel 60 in advance, and the steel grade of the cast steel 60 and When the speed measurement value is received and compared with the reference value, and the speed measurement value of the cast steel 60 measured by the speed detection sensor 200 is relatively higher than the reference value, the injection method of the hybrid nozzle 100 is determined. When the water cooling method is selected and the measured value is relatively slower than the reference value, the injection method of the hybrid nozzle 100 is selected as a mist method.

Controlling the pressure of the cooling water and the air supplied to the hybrid nozzle 100 adjusts the pressure of the cooling water and the flow rate of the air supplied to the hybrid nozzle 100 according to the injection method of the hybrid nozzle 100.

4 is a view showing the pressure relationship between the air and the cooling water according to the injection method of the hybrid nozzle according to an embodiment of the present invention.

As shown in FIG. 4, when the speed of the cast steel 60 is relatively high, the spraying method of the hybrid nozzle 100 is selected as a water cooling method, and the controller 500 closes the air valve 420. The air is not supplied to the hybrid nozzle 100 and the shutoff valve 430 is closed to prevent the cooling water from flowing back to the air line 410, and at the same time, the hybrid nozzle 100 according to the measured value. The coolant valve 320 is controlled so that the pressure of the coolant supplied to the 8) is 8 to 25 bar.

In addition, when the speed of the cast steel 60 is a relatively low speed, the injection method of the hybrid nozzle 100 is selected as the mist method, and the control unit 500 opens the shutoff valve 430 to the measured value. Accordingly, the air valve 420 is controlled such that the flow rate of air supplied to the hybrid nozzle 100 is 0 to 15 Nm 3 / hr, and at the same time, the pressure of the cooling water supplied to the hybrid nozzle 100 is 0 to 8. The coolant valve 320 is controlled to be bar.

At this time, the control unit 500 is the coolant valve 320, the air valve so that when the pressure of the coolant supplied to the hybrid nozzle 100 is 8 bar or more, the injection method of the hybrid nozzle 100 is a water cooling method. 420 and the shutoff valve 430, and when the pressure of the coolant supplied to the hybrid nozzle 100 is 8 bar mimi, the coolant valve 320 so that the injection method of the hybrid nozzle 100 becomes a mist method. The air valve 420 and the shutoff valve 430 control the control.

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims

A plurality of spray nozzle device provided in the segment of the continuous casting equipment,

A plurality of hybrid nozzles injecting cooling water into a cast steel that passes through the segment in a mist method or a water cooling method;

At least one speed detection sensor installed in the segment to detect the speed of the cast steel passing through the segment;

A cooling water supply unit supplying cooling water to a plurality of the hybrid nozzles;

An air supply unit supplying air to a plurality of the hybrid nozzles; And

Receive the speed of the slab detected by the speed detection sensor, select the spraying method of the hybrid nozzle according to the speed of the received cast, control the cooling water supply unit and the air supply unit of the cooling water supplied to the plurality of hybrid nozzles Hybrid cooling nozzle device comprising a control unit for adjusting the pressure and the flow rate of air.
The method according to claim 1,

The coolant supply unit is provided with a coolant line for supplying coolant to the hybrid nozzle and a coolant valve installed in the coolant line to adjust the pressure of the coolant supplied to the hybrid nozzle,

The air supply unit includes an air line for supplying air to the hybrid nozzle and an air valve installed in the air line to adjust a flow rate of air supplied to the hybrid nozzle; And a shutoff valve for preventing backflow of the coolant,

The control unit controls the cooling water valve and the air valve according to the injection method of the hybrid nozzle.
The method according to claim 2,

And the control unit controls to close the plurality of shutoff valves to prevent the cooling water from flowing into the air line when the pressure of the cooling water supplied to the hybrid nozzle is 8 bar or more.
A method of controlling a nozzle which is provided in a segment of a continuous casting facility and sprays cooling water on a cast steel,

Detecting the steel grade and speed of the cast steel passing through the segment;

Selecting the spraying method of the spray nozzle according to the speed of the cast steel;

And controlling the flow rate of air and the pressure of the cooling water supplied to the spray nozzle according to the spraying method of the selected nozzle.
The method according to claim 4,

Selecting the spray method of the spray nozzle,

Cooling nozzle control method of the continuous casting equipment, characterized in that the spraying method of the nozzle according to the steel grade and the speed of the cast steel to select the mist injection method or water cooling injection method.
The method according to claim 5

Controlling the flow rate of the cooling water supplied to the spray nozzle and the flow rate of the air,

In the case of water-cooled spraying, the pressure of the cooling water supplied to the spray nozzle is controlled to 8 bar or more, and in the case of the mist spraying method, the pressure of the cooling water supplied to the spray nozzle is controlled to less than 8bar. Cooling nozzle control method.