KR20120044425A - Crack diagnosis device of solidified shell in mold and method thereof - Google Patents

Abstract

PURPOSE: A crack diagnosis device of a solidified shell in a mold and a diagnosis method thereof are provided to reduce a fraction defective of slabs manufactured in a continuous casting process by correcting operation conditions when cracks are occurred. CONSTITUTION: A crack diagnosis device(100) of a solidified shell in a mold comprises a temperature detecting part(110) and a control unit(190). The temperature detecting part comprises a plurality of temperature detecting members(111,112). The temperature detecting members are divided into a first group(101) and second group(102) based on an area where cracks are possible to be occurred. The control unit respectively calculates an average temperature for each group by using the detected temperature, thereby extracting the maximum temperature deviation. The control unit diagnoses whether the cracks are occurred or not by using the extracted maximum temperature deviation.

Description

Crack Diagnosis Apparatus and Method for Cracking Solidified Shell in Mold {CRACK DIAGNOSIS DEVICE OF SOLIDIFIED SHELL IN MOLD AND METHOD THEREOF}

The present invention relates to an apparatus and method for diagnosing cracks in solidified shells in a mold for detecting cracks in solidified shells in a mold 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.

Disclosure of Invention It is an object of the present invention to provide a crack diagnosing apparatus for a solidification shell in a mold and a method for diagnosing in real time whether cracks are generated in a large duty free area by using temperature deviation of the solidification shell in a mold in a continuous casting process.

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.

The crack diagnosis apparatus of the present invention for realizing the above object includes a plurality of temperature sensing means arranged in a matrix in a mold, and the plurality of temperature sensing means is divided into a first group and a second group based on the crack-prone region. Divided temperature sensing unit; And calculating the average temperature of the first group and the average temperature of each column of the second group, respectively, from the temperature detected by the temperature sensing unit, and subtracting the calculated average temperature of the first group and the average temperature of each column of the second group. And extracting the maximum temperature deviation, and using the extracted maximum temperature deviation to diagnose whether or not a crack has occurred in the solidification shell.

Specifically, the first group includes at least one temperature sensing means existing in an area where cracks do not occur, and the second group includes at least one temperature sensing means existing in an area where cracks occur. The temperature sensing means belonging to the second group is disposed at the center of the mold, and the temperature sensing means belonging to the first group is disposed at both edges of the mold.

In addition, the temperature sensing means belonging to the second group is characterized in that located within the range of 15% of the width of the mold relative to the center vertical line of the mold.

The controller compares the extracted maximum temperature deviation with a preset reference value and diagnoses whether the solidification shell is cracked. The controller determines the average temperature of the temperature sensing means belonging to the first group at the temperature detected by the temperature sensing unit. And an average temperature calculator for calculating an average temperature for each column of the temperature sensing means belonging to the second group. A deviation extracting unit extracting a maximum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively, calculated above; And a crack determination unit for diagnosing whether the solidification shell is cracked by comparing the extracted maximum temperature deviation with a predetermined reference value.

Another crack diagnosis apparatus of the present invention for realizing the above object comprises a plurality of temperature sensing means arranged in a matrix in a mold, wherein the plurality of temperature sensing means is based on the crack-prone region and the first group and the second group. Temperature sensing unit divided into; And calculating the average temperature of the first group and the average temperature of each column of the second group, respectively, from the temperature detected by the temperature sensing unit, and subtracting the calculated average temperature of the first group and the average temperature of each column of the second group. And extracting the maximum temperature deviation and the minimum temperature deviation, and using the extracted maximum temperature deviation and minimum temperature deviation to diagnose whether or not a crack has occurred in the solidification shell.

The control unit may subtract the extracted maximum temperature deviation and minimum temperature deviation, and compare the temperature deviation obtained by subtraction with a predetermined threshold value to diagnose whether the solidification shell is cracked.

Specifically, the control unit, the average temperature calculation unit for calculating the average temperature for each column of the temperature sensing means belonging to the first group and the temperature sensing means belonging to the second group at the temperature detected through the temperature sensing unit, respectively ; A deviation extracting unit configured to extract the maximum temperature deviation and the minimum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively; And a crack determination unit for subtracting the maximum temperature deviation and the minimum temperature deviation extracted from the above, comparing the temperature deviation obtained by the subtraction with a preset threshold, and diagnosing the crack of the solidification shell.

Crack diagnosis method of the present invention for realizing the above object is, a plurality of temperature sensing means arranged in a matrix in the mold, the step of detecting the mold temperature through the temperature sensing means arranged in a matrix; Calculating an average temperature with respect to the temperatures detected by the first group of temperature sensing means existing in a region where cracks do not occur at the detected mold temperature; Calculating an average temperature for each row with respect to the temperatures detected by the second group of temperature sensing means existing in the region where cracks are generated at the detected mold temperature; And extracting the maximum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group calculated above, and using the extracted maximum temperature deviation, cracks occur for the solidified shell discharged from the mold. Diagnosing; characterized in that it comprises a.

The diagnosing may include diagnosing cracks of the solidification shell by comparing the extracted maximum temperature deviation with a predetermined reference value.

Another crack diagnosis method of the present invention for realizing the above object is a plurality of temperature sensing means arranged in a matrix in the mold, the step of detecting the mold temperature through the temperature sensing means arranged in a matrix; Calculating an average temperature with respect to the temperatures detected by the first group of temperature sensing means existing in a region where cracks do not occur at the detected mold temperature; Calculating an average temperature for each row with respect to the temperatures detected by the second group of temperature sensing means existing in the region where cracks are generated at the detected mold temperature; Extracting the maximum temperature deviation and the minimum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively; And subtracting the maximum temperature deviation and the minimum temperature deviation extracted above to obtain a temperature deviation, and then comparing the obtained temperature deviation with a preset threshold to diagnose cracking of the solidification shell.

According to the present invention, by diagnosing cracks by duty free on the basis of the temperature deviation of the solidification shell produced in the continuous casting process, the surface of the slab is to be scarfed only when the cracks are duty free, thereby correcting the slab. The cost can be reduced.

In addition, the present invention has the effect of reducing the error rate of the slab produced in the continuous casting process by correcting the operating conditions when the crack occurs duty free in the slab.

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.
FIG. 3 is a conceptual view illustrating a distribution form of molten steel M in the mold of FIG. 2 and a portion adjacent thereto.
4 is a view showing a crack diagnostic apparatus of the solidified shell in the mold according to an embodiment of the present invention.
5 is a view showing a temperature sensing means disposed on the long side of the mold according to the present invention.
6 is a flowchart illustrating a crack diagnosis process of the coagulation shell according to an embodiment of the present invention.
7 is a view showing a measurement temperature of the solidification shell in the mold according to the present invention.
8 is a view for explaining the cracks in the mold.
9 is a flowchart illustrating a crack diagnosis process of the coagulation shell according to another embodiment of the present invention.
FIG. 10 is a graph showing the temperature deviation calculated by FIG. 9 on a time axis.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. Like elements in the figures are denoted by the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

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 maintains the shape of the strands extracted from the mold 30 and forms a strong solidification angle or solidified shell 81 so that molten metal, which is still less solidified, does not flow out. Play a role. 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 oxidation and nitriding prevention and thermal insulation of the molten metal in the mold 30, and the non-metal 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 to be immersed in the molten steel in the tundish 20 so that the molten steel M is not exposed to air and oxidized and nitrified. 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.

The shape of the molten steel M in the mold 30 and the portion adjacent thereto will be described with reference to FIG. 3. FIG. 3 is a conceptual view illustrating a distribution form of molten steel M in the mold 30 and adjacent portions of FIG. 2.

Referring to FIG. 3, a pair of discharge ports 25a are typically formed on the end side of the immersion nozzle 25 on the left and right in the drawing. The shapes of the mold 30 and the immersion nozzle 25 are assumed to be symmetrical with respect to the center line C, and thus only the left side is shown in this drawing.

The molten steel M discharged together with the argon (Ar) gas from the discharge port 25a draws a trajectory flowing in the upward direction A1 and downward direction A2 as indicated by arrows A1 and A2. do.

The powder layer 51 is formed on the upper part of the mold 30 by the powder supplied from the powder feeder 50 (see FIG. 1). The powder layer 51 may include a layer existing in a form in which the powder is supplied and a layer sintered by the heat of the molten steel M (sintered layer is formed closer to the unsolidified molten steel 82). Below the powder layer 51, a slag layer or a liquid fluidized layer 52 formed by melting powder by molten steel M is present. The liquid fluidized bed 52 maintains the temperature of the molten steel M in the mold 30 and blocks the penetration of foreign matter. A portion of the powder layer 51 solidifies at the wall surface of the mold 30 to form the lubrication layer 53. The lubrication layer 53 functions to lubricate the solidified shell 81 so as not to stick to the mold 30.

The thickness of the solidification shell 81 becomes thicker as it progresses along the casting direction. The portion of the solidification shell 81 located in the mold 30 is thin and an oscillation mark 87 may be formed by oscillation of the mold 30. The solidification shell 81 is supported by the support roll 60, the thickness thereof is thickened by the spray means 65 for spraying water. The solidification shell 81 may be thickened and a bulging region 88 may be formed in which a portion protrudes convexly.

Here, when the amount of heat transfer exiting the mold 30 is nonuniform, the thickness of the central portion of the solidification shell 81 becomes thin. The solidification shell 81 is unevenly solidified due to fluctuations in the molten steel level in the mold, severe flow (turbulent or drift development) in the mold, and uneven inflow of the mold powder.

On the other hand, the non-uniformly coagulated shell 81 has a tensile force applied to the site where the non-uniform coagulation layer occurs due to phase transformation and thermal contraction, so that an air gap is formed between the mold 30 and the coagulation shell 81. As a result, cracks occur in the solidification shell 81. In this case, the crack may be generated on the surface of the solidification shell 81, but may be generated inside.

Therefore, the crack diagnosis apparatus according to the present invention is to diagnose whether the crack of the coagulation shell 81 is generated, to accurately extract the cracks generated slab and to perform scarfing.

4 is a view illustrating a crack diagnosis apparatus of a solidification shell in a mold according to an embodiment of the present invention, wherein the crack diagnosis apparatus 100 includes a temperature sensing unit 110, a memory 130, a display unit 150, and an input unit ( 170 and the controller 190.

The temperature sensing unit 110 includes a plurality of temperature sensing means 111 and 112 disposed in a matrix form on the mold long side 31. A plurality of temperature sensing means (111, 112) is disposed in the mold 30, thereby detecting the temperature of the mold 30 in real time during the continuous casting process. The temperature of the mold 30 is considered to be the same as the temperature of the solidification shell 81 present inside the mold.

Here, each of the temperature sensing means 111 and 112 has identification information for identifying the region disposed in the mold 30. Therefore, when the temperature of the mold 30 is sensed by the temperature sensing means 111 and 112, the temperature sensing unit 110 transmits the sensed temperature information to the control unit 170.

Here, each of the temperature sensing means 111 and 112 of the temperature sensing unit 110 is disposed in a matrix form on the mold long side 31 as illustrated in FIG. 5. The temperature sensing means 111 and 112 may be any one of a thermocouple and a temperature sensing sensor.

A plurality of temperature sensing means (111, 112) disposed in the mold 30 is divided into a first group 101 and a second group 102 on the basis of the crack-prone area, the crack is generally a mold long side ( 31) in the central part. As shown, the temperature sensing means 112 belonging to the second group 102 is disposed in the center of the mold 30, the temperature sensing means 111 belonging to the first group 101 is the mold 30 Are placed on both sides of the edge. The first group 101 includes at least one or more temperature sensing means 111 disposed in a region where no crack has occurred, and the second group 102 includes at least one or more temperatures disposed in a region where a crack has occurred The sensing means 112 is included. In the exemplary embodiment of the present invention, the temperature sensing means 111 of the first group 101 is six in each row, and the temperature sensing means 112 of the second group 102 is three in each row. The number of matrices and the number of the temperature sensing means 111 and 112 can be changed as necessary.

Here, the temperature sensing means 112 belonging to the second group 102 is located within the range of 15% of the width of the mold 30 on both sides with respect to the center vertical line ⓐ of the mold 30. That is, the second group 102 is located at the center of the mold long side 31, and occupies about 30% of the area ⓑ based on the width of the long side 31.

In FIG. 5, the plurality of temperature sensing means 111 and 112 are disposed on the entire mold long side 31, but may be selectively disposed on an upper portion, a lower portion, or a central portion of the mold long side 31 as necessary. Of course, when the temperature sensing means 111 and 112 are disposed in the entire mold long side 31, the accuracy of crack detection may be improved.

The memory 130 stores a cycle for detecting the temperature of the mold 30, a reference value, a threshold value, and various control programs for determining crack occurrence.

The display unit 150 may display the temperature deviation between the first group 101 and the second group 102 on the time axis. The display unit 150 may display a change amount with respect to the temperature deviation as a graph.

The input unit 170 is configured to receive various operation commands or setting values from the outside and transmit them to the controller 190.

The controller 190 calculates the average temperature of the first group 101 and the average temperature for each column of the second group 102 at the temperature detected by the temperature sensing unit 110, and calculates the calculated first group. The maximum temperature deviation is extracted by subtracting the average temperature of each column and the average temperature of each column of the second group, and comparing the extracted maximum temperature deviation with a preset reference value for the solidification shell 81 discharged from the mold 30. Diagnose cracks. Wherein the average temperature of the first group is the average temperature for the temperatures detected through all the temperature sensing means belonging to the first group, the average temperature for each column of the second group is detected through the temperature sensing means belonging to the second group The average temperature for each column at the given temperature.

For example, when the temperature sensing means 111 and 112 are arranged in the form of an N (row) ㅧ 9 (column) matrix as shown in FIG. 5, the first group 101 includes columns 1, 2, 3, 7, The temperature sensing means 111 belonging to the eighth row and the ninth row, and the second group 102 are the temperature sensing means 112 belonging to the fourth row, the fifth row and the sixth row. Therefore, the average temperature of the first group 101 is the average temperature of all the temperature sensing means belonging to the first column, the second column, the third column, the seventh column, the eighth column, and the nineth column, and the average temperature of each column of the second group 102. May be divided into an average temperature for the fourth row 102-1, an average temperature for the fifth row 102-2, and an average temperature for the sixth row 102-3.

The controller 190 may be functionally configured to include an average temperature calculator 191, a deviation extractor 193, and a crack determination unit 195.

The average temperature calculator 191 is the temperature detected by the temperature sensing unit 110, the average temperature of the temperature sensing means 111 belonging to the first group 101 and the temperature sensing means belonging to the second group 102 ( The average temperature is calculated for each of the columns 102-1 to 102-3 of 112.

The deviation extractor 193 extracts the maximum temperature deviation by subtracting the calculated average temperature of the first group 101 and the average temperature of each column 102-1 to 102-3 of the second group 102, respectively. . Of course, the deviation extractor 191 measures the average temperature and the maximum temperature deviation of the extracted average temperature of each of the first group 101 and the columns 102-1 to 102-3 of the second group 102. And may be temporarily stored in the memory 130.

The crack determination unit 195 compares the maximum temperature deviation extracted through the deviation extraction unit 193 with a preset reference value to diagnose whether the solidification shell is cracked.

The controller 190 may display the maximum temperature deviation calculated by the deviation extractor 193 on the display unit 150.

On the other hand, the controller 190 is the temperature detected by the temperature sensing unit 110, the average temperature of the first group 101 and for each column (102-1 ~ 102-3) of the second group 102 The average temperature is calculated, and the maximum temperature deviation and the minimum temperature deviation are subtracted by subtracting the calculated average temperature of the first group 101 and the average temperature for each column 102-1 to 102-3 of the second group 102. Are extracted and the cracks on the coagulation shell are diagnosed using the extracted maximum and minimum temperature deviations. In addition, when diagnosing whether the solidification shell is cracked, the controller 190 acquires a temperature deviation by subtracting the extracted maximum temperature deviation and the minimum temperature deviation, and compares the obtained temperature deviation with a preset threshold value. If exceeded, it is diagnosed that a crack has occurred in the solidification shell (81). In this case, the average temperature of the first group 101 is the average temperature of the temperatures detected through all the temperature sensing means 111 belonging to the first group 101, and each row 102 of the second group 102 is used. The average temperature for each of -1 to 102-3 is an average temperature for each column 102-1 to 102-3 at a temperature detected through the temperature sensing unit 112 belonging to the second group 102.

The controller 190 may be functionally configured to include an average temperature calculator 191, a deviation extractor 193, and a crack determination unit 195.

The average temperature calculator 191 is the temperature detected by the temperature sensing unit 110, the average temperature of the temperature sensing means 111 belonging to the first group 101 and the temperature sensing means belonging to the second group 102 ( The average temperature is calculated for each of the columns 102-1 to 102-3 of 112.

The deviation extractor 193 subtracts the calculated average temperature of the first group 101 and the average temperature of each column 102-1 to 102-3 of the second group 102, respectively, to thereby maximize the maximum temperature deviation and the minimum temperature. Each deviation is extracted. Of course, the deviation extraction unit 191 is the average temperature of the extracted first group 101 and the average temperature, the maximum temperature deviation and the minimum temperature deviation for each column (102-1 ~ 102-3) of the second group 102 May be temporarily stored in the memory 130 together with the measurement time information.

The crack determination unit 195 subtracts the maximum temperature deviation and the minimum temperature deviation extracted through the deviation extraction unit 193, and compares the temperature deviation obtained by subtracting the preset temperature with a preset threshold to diagnose whether the solidification shell is cracked. do.

The controller 190 may display the temperature deviation between the maximum temperature deviation and the minimum temperature deviation calculated by the crack determination unit 193 on the display unit 150.

6 is a flowchart illustrating a crack diagnosis process of the solidification shell according to an embodiment of the present invention, it will be described with reference to the accompanying drawings.

While the continuous casting process is performed, the temperature sensing unit 110 senses the temperature of the mold 30 in real time in a region where the respective temperature sensing means 111 and 112 are disposed and transmits the temperature to the control unit 190 (S11). , S12). At this time, the temperature detection unit 110 transmits identification information for each of the temperature detection means (111, 112) with the temperature information to the control unit 190, the control unit 190 is the first temperature information from the transmitted identification information It can be seen whether it belongs to the group 101 or the second group 102.

The plurality of temperature sensing means 111 and 112 are divided into a first group 101 and a second group 102 on the basis of a crack generation area, and the first group 101 is a mold in which no crack is generated. The second side 102 is disposed at both edges of the long side 31, and the second group 102 is disposed at the center of the mold long side 31 where cracks are generated.

FIG. 7 shows the temperature of the mold at a specific time point, and shows the temperature of the mold 30 detected through the temperature sensing means 111 and 112 located at 1, 2, and 3 rows of the specific time point.

As shown in FIG. 7, the temperature of the mold 30 varies depending on the position, and it can be seen that the temperature change is particularly severe at the central portion of the mold 30.

Subsequently, when the set temperature measurement time arrives, the controller 190 uses the temperature information on the temperature sensing means 111 corresponding to the first group 101 existing in the region where the crack does not occur. Calculate the overall average temperature of (S13).

The controller 190 calculates the average temperature of the first group 101 and then detects the temperatures detected by the temperature sensing means 112 of the second group 102 existing in the region where the crack is generated. For each column (102-1 ~ 102-3) to calculate the average temperature (S14). That is, in the first group 101, one average temperature value exists regardless of the number of columns, but in the second group 102, three average temperature values exist when the number of columns is three.

The controller 190 extracts the maximum temperature deviation by subtracting the average temperature of the first group 101 and the average temperature of each column 102-1 to 102-3 of the second group 102 calculated above. In operation S15, the extracted maximum temperature deviation is temporarily stored in the memory 130 together with the measurement time information. In this case, the controller 190 may display the calculated maximum temperature deviation on the display unit 150 on a time axis. In the above, when the temperature sensing means of the second group 102 is composed of three rows, the average temperature of the first group 101 and the average of each row 102-1 to 102-3 of the second group 102 are measured. Subtracting the temperature respectively will generate three temperature deviation values, and the controller extracts the maximum temperature deviation value which is the maximum value of the three temperature deviation values.

Subsequently, the controller 190 compares the extracted maximum temperature deviation with a preset reference value to diagnose whether the solidification shell is cracked (S16). Here, when the maximum temperature deviation exceeds the reference value, the controller 190 diagnoses that a crack has occurred in the solidification shell 81.

When the maximum temperature deviation extracted above exceeds the reference value, as shown in FIG. 8, duty free cracks are formed in the central portion of the mold long side 31, that is, in the solidification shell 81 located in the second group 102. Diagnose as occurring. In addition, the crack of the solidification shell in the mold is generated in the heat generated the maximum temperature deviation. For example, if the maximum temperature deviation is generated on the 4th row 102-1 side of the 4th to 6th row of the second group 102, cracks may be generated vertically as shown in FIG. 8 in the solidification shell in the mold. In the crack diagnosis algorithm according to the present invention, as shown in FIG. 8, a crack-free duty detection of a large duty-free crack in which duty-free cracks are generated long along the column direction of the second group 102 is relatively excellent.

9 is a flowchart illustrating a crack diagnosis process of a solidification shell according to another embodiment of the present invention, which will be described with reference to the accompanying drawings.

While the continuous casting process is performed, the temperature sensing unit 110 detects the temperature of the mold 30 in real time in the region where the respective temperature sensing means 111 and 112 are disposed and transmits the temperature to the control unit 190 (S21). , S22).

The plurality of temperature sensing means 111 and 112 are divided into a first group 101 and a second group 102 on the basis of a crack generation area, and the first group 101 is a mold in which no crack is generated. The second side 102 is disposed at both edges of the long side 31, and the second group 102 is disposed at the center of the mold long side 31 where cracks are generated.

Subsequently, when the set temperature measurement time arrives, the controller 190 uses the temperature information on the temperature sensing means 111 corresponding to the first group 101 existing in the region where the crack does not occur. Calculate the overall average temperature of (S23).

The controller 190 calculates the average temperature of the first group 101 and then detects the temperatures detected by the temperature sensing means 112 of the second group 102 existing in the region where the crack is generated. Calculate the average temperature for each row (102-1 ~ 102-3) for (S24). That is, in the first group 101, one average temperature value exists regardless of the number of columns, but in the second group 102, three average temperature values exist when the number of columns is three.

The controller 190 subtracts the average temperature of each of the columns 102-1 to 102-3 of the first group 101 and the average temperature of the second group 102, respectively, by calculating the maximum temperature deviation and the minimum temperature. Deviation is extracted (S25). In the above, when the temperature sensing means of the second group 102 is composed of three rows, the average temperature of the first group 101 and the average of each row 102-1 to 102-3 of the second group 102 are measured. Subtracting the temperature, respectively, three temperature deviation values will be generated, and the controller 190 extracts the maximum temperature deviation, which is the maximum value, and the minimum temperature deviation, which is the minimum value, of the three temperature deviation values, respectively.

Subsequently, the controller 190 subtracts the extracted maximum temperature deviation and the minimum temperature deviation (S26), and then compares the temperature deviation obtained by subtraction with a predetermined threshold value to diagnose whether the solidification shell is cracked (S27). Here, the controller 190 diagnoses that a crack has occurred in the solidification shell 81 when the obtained temperature deviation is greater than or equal to a threshold value. In this case, the controller 190 may display the obtained temperature deviation on the display unit 150 on a time axis.

If the crack is diagnosed in the solidification shell in the mold, the crack generation point will be the heat of the second group 102 where the maximum temperature deviation is generated, not the minimum temperature deviation.

In FIG. 10, the y axis is a time axis representing the temperature deviation calculated by FIG. 9, and the temperature deviation of the y axis is the average temperature of the first group 101 and each column 102-1 to 2 of the second group 102. 102-3) Temperature deviation obtained by subtracting the average temperature of each star.

As shown in the figure, when the temperature deviation D _{T obtained} by subtracting the maximum temperature deviation Tmax and the minimum temperature deviation Tmin exceeds the set threshold, the cracks in the solidification shell 81 in the mold 30 are vertically cracked. Diagnose as occurring.

That is, when the temperature deviation exceeds the threshold value, as shown in FIG. 8, it is diagnosed that the duty free crack is generated in the solidification shell 81 located in the second group 102 which is the center of the mold long side 31. do. For example, the maximum temperature deviation is generated on the 4th column 102-1 side of the 4th to 6th row of the second group 102, and the maximum temperature deviation and the minimum temperature deviation of any one column (5th or 6th column) If the temperature deviation obtained by subtracting exceeds the threshold value, it is considered that cracks are generated on the four rows of the second group 102 vertically. The crack diagnosis algorithm according to the present invention has a relatively large duty free crack detection performance in which a duty free crack is generated long along the column direction of the second group 102.

As described above, in the present invention, cracks are diagnosed by duty free on the basis of the temperature variation of the solidification shell produced in the continuous casting process, so that the surface of the slab is subjected to scarfing only when the crack is generated by duty free correction. The cost can be reduced. In particular, the present invention can more accurately detect cracks generated by the temperature sensing means located in the second group 102.

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 31: mold long side
35: mold short side 40: mold oscillator
50: powder feeder 51: powder layer
52: liquid fluidized bed 53: lubricating layer
60: support roll 65: spray
70: pinch roll 80: strand
81: solidified shell 82: unsolidified molten steel
83: tip 85: solidification completion point
87: oscillation mark 88: bulging area
90: cutting machine 91: cutting point
100: crack diagnosis apparatus 101: the first group
102: second group 110: temperature sensing unit
111: temperature sensing means of the first group 112: temperature sensing means of the second group
130: memory 150: display unit
170: input unit 190: control unit
191: average temperature calculation unit 193: deviation extraction unit
195: crack determination

Claims (15)

A temperature sensing unit having a plurality of temperature sensing means arranged in a matrix in the mold, wherein the plurality of temperature sensing means is divided into a first group and a second group based on a crack-prone region; And
From the temperature detected by the temperature sensing unit, the average temperature of each column of the first group and the average value of each column of the second group are respectively calculated, and the calculated average temperature of the first group and the average temperature of each column of the second group are subtracted. And a control unit for extracting a maximum temperature deviation and diagnosing crack occurrence for the coagulation shell using the extracted maximum temperature deviation.
The method according to claim 1,
The first group includes at least one temperature sensing means in a region where no crack occurs, and the second group includes at least one temperature sensing means in a region where the crack occurs. Crack Diagnosis Device.
The method according to claim 1,
The control unit is a crack diagnosing apparatus of the solidified shell in the mold for diagnosing the crack of the solidified shell by comparing the extracted maximum temperature deviation with a predetermined reference value.
The method according to claim 1,
The temperature sensing means belonging to the second group is disposed in the center of the mold, the temperature sensing means belonging to the first group is crack diagnosis apparatus of the solidification shell in the mold is disposed on both edges of the mold.
The method according to claim 1,
The temperature sensing means belonging to the second group is crack diagnostic apparatus of the solidified shell in the mold is located within the range of 15% of the width of the mold, respectively, based on the center vertical line of the mold.
The method according to claim 1,
The control unit,
An average temperature calculator configured to calculate an average temperature of each of the rows of the temperature sensing means belonging to the first group and the average temperature of the temperature sensing means belonging to the second group at the temperature detected by the temperature sensing part;
A deviation extracting unit extracting a maximum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively, calculated above; And
And crack determination unit for diagnosing whether the solidification shell is cracked by comparing the extracted maximum temperature deviation with a predetermined reference value.
A temperature sensing unit having a plurality of temperature sensing means arranged in a matrix in the mold, wherein the plurality of temperature sensing means is divided into a first group and a second group based on a crack-prone region; And
From the temperature detected by the temperature sensing unit, the average temperature of each column of the first group and the average value of each column of the second group are respectively calculated, and the calculated average temperature of the first group and the average temperature of each column of the second group are subtracted. And a control unit configured to extract a maximum temperature deviation and a minimum temperature deviation, and diagnose whether or not a crack has occurred in the coagulation shell using the extracted maximum temperature deviation and the minimum temperature deviation.
The method according to claim 7,
And the control unit subtracts the extracted maximum temperature deviation and minimum temperature deviation, and compares the temperature deviation obtained by subtraction with a predetermined threshold value to diagnose cracks of the solidification shell.
The method according to claim 7,
The first group includes at least one temperature sensing means in a region where no crack occurs, and the second group includes at least one temperature sensing means in a region where the crack occurs. Crack Diagnosis Device.
The method according to claim 7,
The temperature sensing means belonging to the second group is crack diagnostic apparatus of the solidified shell in the mold is located within the range of 15% of the width of the mold, respectively, based on the center vertical line of the mold.
The method according to claim 7,
The control unit,
An average temperature calculator configured to calculate an average temperature of each of the rows of the temperature sensing means belonging to the first group and the average temperature of the temperature sensing means belonging to the second group at the temperature detected by the temperature sensing part;
A deviation extracting unit configured to extract the maximum temperature deviation and the minimum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively; And
The crack of the solidification shell in the mold comprising; a crack determination unit for subtracting the maximum temperature deviation and the minimum temperature deviation extracted from the above, and comparing the temperature deviation obtained by the subtraction with a predetermined threshold value to diagnose whether the solidification shell is cracked. Diagnostic device.
A plurality of temperature sensing means arranged in a matrix in the mold, and detecting the mold temperature through the temperature sensing means arranged in the matrix;
Calculating an average temperature with respect to the temperatures detected by the first group of temperature sensing means existing in a region where cracks do not occur at the detected mold temperature;
Calculating an average temperature for each row with respect to the temperatures detected by the second group of temperature sensing means existing in the region where cracks are generated at the detected mold temperature; And
The maximum temperature deviation is extracted by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively, and whether cracks have occurred for the solidified shell discharged from the mold by using the extracted maximum temperature deviation. Diagnosing a crack of the solidified shell in the mold comprising a.
The method of claim 12,
The diagnosing may include cracking the solidified shell in the mold to diagnose whether the solidified shell is cracked by comparing the extracted maximum temperature deviation with a predetermined reference value.
The method of claim 12,
The temperature sensing means belonging to the area where the crack is generated is disposed in the center of the mold, the temperature sensing means belonging to the area where the crack does not occur is disposed on both edges of the mold.
A plurality of temperature sensing means arranged in a matrix in the mold, and detecting the mold temperature through the temperature sensing means arranged in the matrix;
Calculating an average temperature with respect to the temperatures detected by the first group of temperature sensing means existing in a region where cracks do not occur at the detected mold temperature;
Calculating an average temperature for each row with respect to the temperatures detected by the second group of temperature sensing means existing in the region where cracks are generated at the detected mold temperature;
Extracting the maximum temperature deviation and the minimum temperature deviation by subtracting the average temperature of the first group and the average temperature of each column of the second group, respectively; And
The method of diagnosing cracks in the solidified shell in the mold for diagnosing the crack of the solidified shell by comparing the obtained temperature deviation with a predetermined threshold value after obtaining the temperature deviation by subtracting the extracted maximum temperature deviation and the minimum temperature deviation.

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