KR101224955B1

KR101224955B1 - Device for controlling cooling of strand and method therefor

Info

Publication number: KR101224955B1
Application number: KR1020100084160A
Authority: KR
Inventors: 문홍길; 조원재; 최주태
Original assignee: 현대제철 주식회사
Priority date: 2010-08-30
Filing date: 2010-08-30
Publication date: 2013-01-22
Also published as: KR20120020508A

Abstract

The present invention relates to a strand cooling controller and a method for controlling the cooling temperature of the strands to be maintained in a continuous casting process, and a plurality of nozzles for respectively spraying the cooling water to the center and the edge of the strands to be carried out from the mold It includes, the spray means for adjusting the spray angle of each nozzle, the spray angle adjusting unit for adjusting the spray angle of the nozzles respectively sprayed to the center and the edge of the strand, and the width of the strand and the installation position of the spray means A cooling control unit for calculating the injection angle of the nozzles respectively injected to the central portion and the edge portion of the strand on the basis of the information, and to control the nozzle to be varied by the injection angle calculated by the injection angle control unit is provided.

Description

Strand cooling control device and its method {DEVICE FOR CONTROLLING COOLING OF STRAND AND METHOD THEREFOR}

The present invention relates to a strand cooling device, and more particularly, to a strand cooling control device and a method for controlling the cooling temperature of the strand to be maintained in a continuous casting process.

In general, a continuous casting machine is a facility for producing cast steel of a certain size by receiving a molten steel produced in a steelmaking furnace and transferred to a ladle in a tundish and then supplying it to a mold for continuous casting.

The continuous casting machine includes a ladle for storing molten steel, a continuous casting machine mold for cooling the tundish and the molten steel discharged from the tundish into a strand having a predetermined shape, and a strand formed from the mold connected to the mold. It includes a plurality of pinch rolls to move.

In other words, the molten steel tapping out of the ladle and the tundish is formed of a strand having a predetermined width, thickness, and shape in a mold and is transferred through a pinch roll, and the strand transferred through the pinch roll is cut by a cutter to have a predetermined shape. It is made of a slab (Slab) or a slab (Bloom), billet (Billet) and the like.

Cooling water spray is installed between the pinch rolls, the cooling water and air is injected into the strand through the spray to lower the temperature of the strand.

An object of the present invention and a strand cooling control device that can reduce the temperature variation in the width direction of the strand by adjusting the spray angle or the injection amount of the cooling water according to the width of the strand and the type of steel or the installation position of the spray means in the continuous casting process To provide a way.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the particular embodiments that are described. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, There will be.

Strand cooling control apparatus of the present invention for realizing the above object comprises a plurality of nozzles for respectively spraying the coolant to the central portion and the edge portion of the strand to be carried out from the mold, spray means for adjusting the spray angle of each nozzle; An injection angle adjusting unit configured to adjust an injection angle of the nozzles respectively injected to the center and the edge of the strand; And calculating the spray angles of the nozzles respectively injected to the center and the edge of the strand based on the width of the strands and the information on the installation position of the spray means, and the nozzles at the spray angles calculated by the spray angle adjusting unit. It includes; cooling control unit for controlling to be variable.

Specifically, the plurality of nozzles are individually controlled the injection angle by the injection angle adjustment unit.

The information on the installation position of the spray means includes at least one of the distance between the strand and the spray means, the distance between adjacent nozzles, and the width at which spraying overlaps between adjacent nozzles.

The apparatus further includes an injection amount adjusting unit for individually adjusting the amount of cooling water of the nozzles respectively injected into the center and the edge of the strand.

As the width of the strand is narrower, the cooling control unit controls the injection angle of the nozzle injected into the center of the strand larger than the edge of the strand, and as the width of the strand is wider, the cooling control unit is sprayed to the edge of the strand than the center of the strand. The spray angle of the nozzle to be controlled is made larger.

The cooling control unit receives the information including the width of the strand and the installation position of the spray means from the outside and stores the information in the memory.

Strand cooling control method of the present invention for achieving the above object, the first step of collecting the basic information including the width of the strand and the installation position of the spray means; A second step of calculating an injection angle of each nozzle of the spray means respectively sprayed to the central portion and the edge portion of the strand based on the basic information; And a third step of variably controlling the spray angles of the nozzles respectively sprayed to the center portion and the edge portion of the strand by the spray angle calculated above.

The installation position of the spray means includes at least any one of the interval between the strand and the spray means, the distance between adjacent nozzles, and the width at which injection between adjacent nozzles overlaps.

According to the present invention as described above, it is possible to homogenize in the width direction by adjusting the spray angle and the amount of cooling water in the direction of reducing the temperature deviation between the center and the edge of the strand according to the width of the strand and the installation position of the spray means, Control has the advantage of improving the surface and internal quality of the strands.

1 is a side view showing a continuous casting machine according to an embodiment of the present invention.
FIG. 2 is a conceptual view illustrating the continuous casting machine of FIG. 1 based on the flow of molten steel M. Referring to FIG.
3 is a view showing a strand cooling control apparatus according to an embodiment of the present invention.
4 is a view showing a detailed configuration of the spray means of FIG.
5 to 7 are views each showing the spray angle of the spray means according to the width of the strand according to the present invention.
8 is a flowchart illustrating a strand cooling control process according to an embodiment of the present invention.
9 and 10 are diagrams for explaining the temperature deviation and uniformity in the width direction of the strand.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like elements in the figures are denoted by the same reference numerals wherever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1 is a side view showing a continuous casting machine according to an embodiment of the present invention.

Referring to this drawing, the continuous casting machine may include a tundish 20, a mold 30, secondary cooling tables 60 and 65, a pinch roll 70, and a cutter 90.

A tundish 20 is a container for receiving molten metal from a ladle 10 and supplying molten metal to a mold 30. Ladle 10 is provided in a pair, alternately receives molten steel to supply to the tundish 20. In the tundish 20, the supply rate of the molten metal flowing into the mold 30 is controlled, the molten metal is distributed to each mold 30, the molten metal is stored, and the slag and the nonmetallic inclusions are separated.

The mold 30 is typically made of water-cooled copper and allows the molten steel to be primary cooled. The mold 30 has a pair of structurally opposed faces open to form a hollow portion for receiving molten steel. In the case of manufacturing a slab, the mold 30 includes a pair of barriers and a pair of end walls connecting the barriers. Here, the short wall has a smaller area than the barrier. The walls of the mold 30, mainly short walls, may be rotated away from or close to each other to have a certain level of taper. This taper is set to compensate for shrinkage caused by solidification of the molten steel M in the mold 30. The degree of solidification of the molten steel (M) will vary depending on the carbon content, the type of powder (steel cold Vs slow cooling), casting speed and the like depending on the steel type.

The mold 30 has a strong solidification angle or solidifying shell 81 (see FIG. 2) so that the strands extracted from the mold 30 retain their shape and the molten metal, which is still less solidified, does not flow out. It serves to form. The water cooling structure includes a method of using a copper pipe, a method of drilling a water cooling groove in the copper block, and a method of assembling a copper pipe having a water cooling groove.

The mold 30 is oscillated by the oscillator 40 to prevent the molten steel from sticking to the wall of the mold. Lubricants are used to reduce friction between the mold 30 and the strands during oscillation and to prevent burning. Lubricants include splattered flat oil and powder added to the molten metal surface in the mold 30. The powder is added to the molten metal in the mold 30 to become slag, as well as the lubrication of the mold 30 and the strands, as well as the prevention of oxidative and nitrification of the molten metal in the mold 30, thermal insulation, and non-metallic inclusions on the surface of the molten metal. It also performs the function of absorption. In order to inject the powder into the mold 30, a powder feeder 50 is installed. The part for discharging the powder of the powder feeder 50 faces the inlet of the mold 30.

The secondary cooling zones 60 and 65 further cool the molten steel primarily cooled in the mold 30. The primary cooled molten steel is directly cooled by the spray means 65 for spraying water while maintaining the solidification angle by the support roll 60 not to be deformed. Strand coagulation is mostly achieved by the secondary cooling.

The drawing device adopts a multidrive method using a plurality of sets of pinch rolls 70 and the like to pull out the strands without slipping. The pinch roll 70 pulls the solidified tip of the molten steel in the casting direction, thereby allowing the molten steel passing through the mold 30 to continuously move in the casting direction.

The cutter 90 is formed to cut continuously produced strands to a constant size. As the cutter 90, a gas torch, a hydraulic shear, or the like can be employed.

FIG. 2 is a conceptual view illustrating the continuous casting machine of FIG. 1 based on the flow of molten steel M. Referring to FIG.

Referring to this figure, the molten steel (M) is to flow to the tundish 20 in the state accommodated in the ladle (10). For this flow, the ladle 10 is provided with a shroud nozzle 15 extending toward the tundish 20. The shroud nozzle 15 extends so as to be submerged in the molten steel in the tundish 20 so that the molten steel M is not exposed to the air and oxidized and nitrided. The case where molten steel M is exposed to air due to breakage of shroud nozzle 15 is referred to as open casting.

The molten steel M in the tundish 20 flows into the mold 30 by a submerged entry nozzle 25 extending into the mold 30. The immersion nozzle 25 is disposed in the center of the mold 30 so that the flow of molten steel M discharged from both discharge ports of the immersion nozzle 25 can be symmetrical. The start, discharge speed, and stop of the discharge of the molten steel M through the immersion nozzle 25 are determined by a stopper 21 installed in the tundish 20 corresponding to the immersion nozzle 25. Specifically, the stopper 21 may be vertically moved along the same line as the immersion nozzle 25 to open and close the inlet of the immersion nozzle 25. Control of the flow of the molten steel M through the immersion nozzle 25 may use a slide gate method, which is different from the stopper method. The slide gate controls the discharge flow rate of the molten steel M through the immersion nozzle 25 while the sheet material slides in the horizontal direction in the tundish 20.

The molten steel M in the mold 30 starts to solidify from the part in contact with the wall surface forming the mold 30. This is because heat is more likely to be lost by the mold 30 in which the periphery is cooled rather than the center of the molten steel M. The rear portion along the casting direction of the strand 80 is formed by the non-solidified molten steel 82 being wrapped around the solidified shell 81 in which the molten steel M is solidified by the method in which the peripheral portion first solidifies.

As the pinch roll 70 (FIG. 1) pulls the tip portion 83 of the fully solidified strand 80, the unsolidified molten steel 82 moves together with the solidified shell 81 in the casting direction. The uncondensed molten steel 82 is cooled by the spray means 65 for spraying the cooling water in the above movement process. This causes the thickness of the uncooled steel (82) in the strand (80) to gradually decrease. When the strand 80 reaches a point 85, the strand 80 is filled with the solidification shell 81 in its entire thickness. The solidified strand 80 is cut to a certain size at the cutting point 91 and divided into slabs P such as slabs.

Solidification is completed by cooling in the strand 80 in the continuous casting process configured as described above, it is important to maintain the target temperature for each position of the strand 80 and uniform cooling in the width direction.

When the width of the strand 80 is reduced, the amount of cooling water at the edge portion in the strand width direction is adjusted to be uniformly cooled in the width direction by reducing the ratio of the cooling water at a constant ratio to the amount of cooling water at the center portion. However, if the ratio of the coolant between the center and the edge is not appropriate, the temperature drop in the corner part due to the temperature variation in the strand width direction and the supercooling of the corner part occurs, resulting in the corner crack or the center segregation due to the uneven solidification in the width direction. May cause quality problems.

3 is a view for explaining a strand cooling control device according to an embodiment of the present invention, the strand cooling control device 100 is a spray means 110, the injection angle control unit 130, the injection amount control unit 150 and It is configured to include a cooling control unit 170.

Spray means 110 is to spray the coolant to the central portion and the edge of the surface of the strand 80 to be carried out from the mold 30, respectively, is configured to control the injection angle. The spray means 110 includes a plurality of nozzles 111 to 115 arranged in a line in the width direction of the strand 80, and the plurality of nozzles spray a predetermined amount of cooling water in the width direction of the strand 80. Here, the plurality of nozzles may be three as shown in Figure 4, the three nozzles are left nozzle 111 for injecting the coolant to the left edge (margin) of the strand 80 along the width direction of the strand (80) And a central nozzle 113 for spraying coolant to the center of the strand 80 and a right nozzle 115 for spraying coolant to the right margin of the strand 80, each nozzle 111 ~ 115 is the spray angle (

,

) Is configured to be individually adjusted. The spray means 110 shown in FIG. 3 has the same components as the spray means 65 of FIG. 2 but with different reference numerals for convenience.

The injection angle adjusting unit 130 individually adjusts the injection angles of the nozzles 111 to 115 of the spray means 110 which are respectively sprayed to the center and margin of the strand 80.

The injection amount adjusting unit 150 adjusts the amount of cooling water of each of the nozzles 111 to 115 of the spray means 110 which are respectively sprayed to the center portion and the edge portion of the strand 80.

The cooling control unit 170 is based on the width of the stored strand 80 and the information on the installation position of the spray means 110, each nozzle of the spray means 110 is sprayed to the center portion and the edge of the strand 80 ( Calculate the injection angle of the 111 ~ 115, and controls so that each nozzle (111 ~ 115) of the spray means 110 is changed to the injection angle calculated by the injection angle adjusting unit 130. The cooling control unit 170 receives the information including the width of the strand 80 and the installation position of the spray means 110 from a predetermined key input unit or an external host device (not shown) and stores the information in the memory 180.

In addition, the cooling control unit 170 is set through the injection amount control unit 150 to set the injection amount of each nozzle (111 ~ 115) to reduce the temperature deviation in the width direction of the strand 80 according to the strand 80 width or steel grade Control by quantity. For example, when the strand 80 is wide, the cooling controller 170 may control the amount of cooling water sprayed from the left nozzle 111, the center nozzle 113, and the right nozzle 115 to the same amount. When 80 is narrow, the amount of cooling water injected from the left and right nozzles 111 and 115 may be controlled to be smaller than the amount of cooling water of the central nozzle 113. When the amount of cooling water sprayed from the central nozzle 113 is 1, the amount of cooling water sprayed from the left and right nozzles 111 and 115 may be about 0.5 to about 0.9.

As shown in FIG. 4, the spacing H between the strand 80 and the spray means 110, the spacing L between adjacent nozzles, and each nozzle are shown in FIG. 4. The injection of may include at least one or more information of the width (C) overlap. W is the width of the strand 80.

5 to 7 are views showing the spray angle of the spray means, respectively, depending on the width of the strands. here,

Is the spray angle of the center nozzle 113 when the strand 80 is wide,

Is the spray angle of the center nozzle 113 when the strand 80 is medium width,

Is the injection angle of the center nozzle 113 when the strand 80 is narrow.

Is the spray angle of the left nozzle 111 and the right nozzle 115 when the strand 80 is wide,

Is the injection angle of the left nozzle 111 and the right nozzle 115 when the strand 80 is medium width,

Is the injection angle of the left nozzle 111 and the right nozzle 115 when the strand 80 is narrow.

As the cooling control unit 170 has a wider width of the strand 80 as shown in FIG. 5, the injection angles of the left nozzle 111 and the right nozzle 115 are sprayed to the edge of the strand 80 rather than the center of the strand 80. Control more.

And, as shown in FIG. 7, the narrower the width of the strand 80, the greater the control angle of the spraying of the central nozzle 113 injected into the center portion of the strand 80 than the edge portion of the strand 80.

Finally, based on the width of the strand 80, the central nozzle 113 has a larger spray angle when narrower than when wide (

), The left nozzle 111 and the right nozzle 115 have a larger injection angle when they are wider than when they are narrow (

).

As described above, the cooling control unit 170 based on the width of the strand 80 and the information on the installation position of the spray means 110, the injection angle of the central nozzle 113 (

) Is determined by calculating, and the calculation method is shown in Equation 1 below.

In addition, the cooling controller 170 divides the left nozzle 111 and the right nozzle 115 of the spray means 110 based on the width of the strand 80 and the information on the installation position of the spray means 110. square(

) Is determined by calculating, and the calculation method is shown in Equation 2 below.

8 is a flowchart illustrating a strand cooling control process according to an embodiment of the present invention.

First, the cooling control unit 170 receives the information including the width of the strand 80 and the installation position of the spray means 110 is received from a predetermined key input unit or an external upper device and stored in the memory 180 (S1). The installation position information of the spray means 110, the spacing (H) between the strand 80 and the spray means 110, the spacing (L) between the adjacent nozzles, and the width (C) that the injection of each nozzle overlaps At least one of the information may be included.

Subsequently, the cooling control unit 170 is each nozzle of the spray means 110 is sprayed to the center portion and the edge portion of the strand 80 based on the basic information on the width of the strand 80 and the installation position of the spray means 110 Calculate the injection angle of (S2). Cooling control unit 170 is the injection angle of the central nozzle 113 (

) Is calculated using Equation 1 above, and the injection angles of the left nozzle 111 and the right nozzle 115 (

) Is calculated using Equation 2 above.

5 to 7, the narrower the strand 80, the greater the spray angle of the central nozzle 113 (

), The wider the strand 80 is, the greater the injection angle of the left nozzle 111 and the right nozzle 115 (

).

The cooling control unit 170 calculates the spray angle of each nozzle of the spray means 110 as described above, and adjusts the spray angle of the central nozzle 113, the left nozzle 111 and the right nozzle 115 by the calculated spray angle. The control unit 130 controls the control unit 130 to be variable (S3).

Meanwhile, the cooling control unit 170 controls the amount of cooling water sprayed from the central nozzle 113, the left nozzle 111, and the right nozzle 115 through the injection amount adjusting unit 150 as an initial set value. Here, the amount of cooling water sprayed through the center nozzle 113, the left nozzle 111, and the right nozzle 115 may vary according to the width of the strand 80. For example, when the strand 80 is wide, the amount of cooling water sprayed from the center nozzle 113, the left nozzle 111, and the right nozzle 115 are the same, and when the strand 80 is narrow, the left nozzle ( The amount of cooling water sprayed from the 111 and the right nozzle 115 may be less than the amount of cooling water spraying from the central nozzle 113.

In general, the surface temperature of the strand 80 may be about 700 ° C to about 1100 ° C, the temperature of the margin (margin) and the center (center) may be different as shown in FIG. In FIG. 9, the edge portion is approximately 50 ° C. to 100 ° C. higher than the center portion, and the strand quality may be degraded due to the temperature deviation in the strand width direction.

Accordingly, if the injection angle of the central nozzle 113, the left nozzle 111 and the right nozzle 115 is variably adjusted based on the information on the width of the strand and the installation position of the spray means 110, as in the present invention, As shown in FIG. 10, the temperature deviation between the center and the margin of the strand 80 may be eliminated.

As described above, in the present invention, it is possible to uniformize the width in the width direction by adjusting the spray angle and the amount of cooling water in the direction of reducing the temperature deviation between the center and the edge of the strand according to the width of the strand and the installation position of the spray means, and through the solidification control. There is an advantage to improve the surface and internal quality of the strand.

The present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

10: ladle 15: shroud nozzle
20: Tundish 25: Immersion Nozzle
30: mold 40: mold oscillator
50: powder feeder 51: powder layer
52: liquid fluidized bed 53: lubricating layer
60: support roll 65: spray means
70: pinch roll 80: strand
81: solidified shell 82: unsolidified molten steel
83: tip 85: solidification completion point
90: cutting machine 91: cutting point
100: strand cooling control device 110: spray means
111,115 left and right nozzles 113: center nozzle
130: injection angle control unit 150: injection amount control unit
170: cooling control unit

Claims

A spraying means including a plurality of nozzles for respectively spraying coolant to the center portion and the edge portion of the strands carried out from the mold, wherein the spray angles of the nozzles are adjusted;
An injection angle adjusting unit configured to adjust an injection angle of the nozzles respectively injected to the center and the edge of the strand; And
On the basis of the information on the width of the strand and the installation position of the spray means calculates the spray angle of the nozzles respectively sprayed to the center and the edge of the strand, the nozzle is variable to the spray angle calculated by the spray angle control unit Strand cooling control device comprising; cooling control unit for controlling to.

The method according to claim 1,
Strand cooling control device wherein the plurality of nozzles are individually controlled by the injection angle control unit.

The method according to claim 1,
Information on the installation position of the spray means,
And at least one of a spacing between the strand and the spray means, a spacing between adjacent nozzles, and a width at which spraying overlaps between adjacent nozzles.

The method according to claim 1,
Strand cooling control device further comprises an injection amount adjusting unit for individually adjusting the amount of cooling water of the nozzles respectively injected to the center and the edge of the strand.

The method according to claim 1,
The cooling control unit is a strand cooling control device for controlling the injection angle of the nozzle that is injected to the center portion of the strand larger than the width of the strand, the narrower the strand.

The method according to claim 1,
The cooling control unit is a strand cooling control device for controlling the injection angle of the nozzle is injected to the edge of the strand larger than the center of the strand, the wider the width of the strand.

The method according to claim 1,
The cooling control unit is a spray angle of the nozzle for spraying coolant to the center of the strand (

) Is a strand cooling control device to determine by the following equation (1).
Equation 1

The method according to claim 1,
The cooling control unit is a spray angle of the nozzle for spraying coolant to the edge of the strand (

) Is a strand cooling control device to determine by the following equation (2).
Equation 2

The method according to claim 1,
The cooling control unit is a strand cooling control device for receiving information from the outside including the width of the strand and the installation position of the spray means stored in the memory.

A first step of collecting basic information including the width of the strand and the installation position of the spray means;
A second step of calculating an injection angle of each nozzle of the spray means respectively sprayed to the central portion and the edge portion of the strand based on the basic information; And
And a third step of variably controlling the injection angles of the nozzles respectively injected into the central and edge portions of the strands using the calculated injection angles.

The method of claim 10,
The installation position of the spray means, the strand cooling control method comprising at least any one of the interval between the strand and the spray means, the interval between the adjacent nozzles, and the width overlapping the injection between the adjacent nozzles.

The method of claim 10,
The spraying angle of the nozzle is injected into the central portion of the strand in the second step is the strand cooling control method is calculated as the narrower the width of the strand.

The method of claim 10,
And a spray angle of the nozzle sprayed to the edge of the strand in the second step is calculated as the width of the strand is wider.