KR20120032923A - Crack diagnosis device of solidified shell in mold and method thereof - Google Patents

Abstract

PURPOSE: A crack diagnosis device and method for a solidified shell in a mold are provided to reduce repair costs by implementing scarfing on a slab surface only in case of vertical crack. CONSTITUTION: A crack diagnosis device for a solidified shell in a mold comprises a temperature sensing unit(110) and a control unit(190). The temperature sensing unit comprises a plurality of temperature sensors which are arranged in a matrix form within the mold and divided into first and second groups(101,102) about a crack generation possible area. The control unit obtains the average temperature of the first group and the average temperature of the other temperature sensors of the second group except for one in each row and diagnoses crack in a solidified shell discharged from the mold using the difference between the average temperatures of the first and second groups.

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 thereof for real-time diagnosis of cracks in duty free by using temperature deviation of 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 an average temperature value of the remaining temperature sensing means except for any one of an average temperature value of the temperature sensing means located in the first group and a temperature sensing means located in the second group at each temperature detected by the temperature sensing unit. And a controller for diagnosing whether a crack has occurred in the solidified shell discharged from the mold by using the temperature deviation between the obtained average temperature value of the first group and the average temperature value of the second group. It features.

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 remaining temperature sensing means in the second group is characterized in that the temperature sensing means adjacent to each other.

The control unit repeatedly obtains the average temperature value of the first group and the average temperature value of the second group, and the temperature deviation of each row for at least one time for a set time, and calculates It is characterized by diagnosing the crack of the solidification shell by comparing the average value and the predetermined reference value.

In addition, the control unit repeatedly collects the average value of the temperature deviation obtained repeatedly for a set unit element time, and compares the maximum fluctuation range with respect to the collected average temperature deviation value and the predetermined threshold value to determine whether the solidification shell is cracked or not. It is characterized by making a diagnosis.

On the other hand, the control unit is characterized by diagnosing the crack of the solidification shell by comparing the maximum average value and the predetermined reference value of the average value of the temperature deviation obtained for each row.

The temperature sensing means belonging to the second group is disposed at the center of the mold, the temperature sensing means belonging to the first group is disposed at both edges of the mold, and the temperature sensing means belonging to the second group is based on the center vertical line of the mold. As is characterized in that positioned in the range of 15% relative to the width of the mold.

The control unit, at the temperature detected by the temperature sensing unit, the average of the remaining temperature sensing means except for any one of the average temperature value of the temperature sensing means belonging to the first group for each row and the temperature sensing means located in the second group A deviation calculator for obtaining temperature values, and calculating a temperature deviation between the obtained average temperature value of the first group and the average temperature value of the second group; A deviation average calculation unit repeatedly obtaining the temperature deviation for a predetermined time and calculating an average value of the repeatedly obtained temperature deviations; And a crack determination unit for diagnosing the crack of the solidification shell by comparing the average value of the temperature deviations calculated above with a predetermined reference value.

Crack diagnosis method of the present invention for achieving the above object, the plurality of temperature sensing means arranged in a matrix matrix, detecting the mold temperature for each row; Calculating an average temperature value with respect to the detected temperature from the temperature sensing means existing in a region where cracks do not occur for each row at the detected mold temperature; Calculating an average temperature value of the temperature sensing means except for any one of the temperature sensing means existing in a region where cracks are generated in each row at the detected mold temperature; And calculating a temperature deviation between the average temperature value of the first group and the average temperature value of the second group for any row obtained above, and using the calculated temperature deviation, whether cracks have occurred for the solidified shell discharged from the mold. Diagnosing; characterized in that it comprises a.

Specifically, the average temperature value of the first group, the average temperature value of the second group, and the temperature deviation are repeatedly obtained at least one or more times for a set time for each row, and the average value of the repeatedly obtained It is characterized by diagnosing cracks of the coagulation shell by comparing the preset reference values.

In addition, it is characterized by diagnosing the crack of the solidification shell by comparing the maximum average value and the predetermined reference value of the average value of the temperature deviation of each row repeatedly obtained.

The diagnosing may include obtaining a temperature deviation by subtracting the average temperature value of the first group and the average temperature value of the second group obtained above; Repeatedly acquiring the temperature deviation for a predetermined time and calculating an average value of the repeatedly obtained temperature deviations; And diagnosing whether the coagulation shell is cracked by comparing the average value of the temperature deviations calculated above with a preset reference value.

In the diagnosing step, the average value of repeatedly obtained temperature deviations is repeatedly collected for a set unit element time, and the maximum variation of the collected temperature deviation average values and the preset threshold are compared with each other to determine the solidification shell. Diagnosing the crack, the unit element time is characterized in that it is set in the range of 15sec to 150sec.

On the other hand, the diagnosing step may include: obtaining a temperature deviation by subtracting the average temperature value of the first group and the average temperature value of the second group obtained above; Repeatedly acquiring the temperature deviation for a predetermined time and storing the average deviation value of the repeatedly obtained temperature deviations; Collecting the deviation mean value repeatedly for a set unit element time and calculating a maximum variation using the maximum and minimum values of the collected deviation mean values; And diagnosing whether the solidification shell is cracked by comparing the calculated maximum variation with a predetermined threshold.

According to the present invention, the 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 scarping only when the cracks are duty free. 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.
FIG. 6 is a graph showing the mean temperature deviation calculated by FIG. 4 on a time axis.
FIG. 7 is a diagram illustrating cracks in a mold. FIG.
8 is a flowchart illustrating a crack diagnosis process of the coagulation shell according to an embodiment of the present invention.
9 is a view showing a measurement temperature of the solidification shell in the mold according to the present invention.
10 is a flowchart illustrating a crack diagnosis process of the coagulation shell according to another embodiment of the present invention.
FIG. 11 is a graph illustrating the mean temperature deviation calculated by FIG. 10 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 embodiment of the present invention, the temperature sensing means 111 of the first group 101 is six, and the temperature sensing means 112 of the second group 102 is three for each row. The number of 111 and 112 can be changed as needed.

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 unit time of measurement, a reference value and a threshold value for determining crack occurrence, various control programs, and the like.

The display unit 150 may display a temperature deviation between the first group 101 and the second group 102 or an average value of the temperature deviation 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 is located in the second group 102 and the average temperature value of the temperature sensing means 111 located in the first group 101 for each row at the temperature detected by the temperature sensing unit 110. Obtaining the average temperature values of the remaining temperature sensing means except for any one of the temperature sensing means 112, and obtaining a temperature between the obtained average temperature value of the first group 101 and the average temperature value of the second group 102. By using the deviation, it is diagnosed whether or not a crack occurs for the solidified shell 81 discharged from the mold (30). In the above, the average temperature value of the first group 101, the average temperature value of the second group 102, and the temperature deviation thereof are obtained for each row.

For example, when the temperature sensing means 111 and 112 are arranged in an N (row) x 9 (column) matrix form as shown in FIG. 5, the first group 101 includes one, two, three, seven, 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.

The controller 190 uses the temperature information detected by the temperature sensing means 111 arranged in the first, second, third, seventh, eighth, and nineth columns of each row of the mold long side 31 to obtain an average temperature value. The average temperature value of the temperature sensing means other than the temperature sensing means 112 arranged in the 4th, 5th, and 6th rows is obtained. Here, it is preferable that the remaining temperature sensing means of the second group 102 are adjacent temperature sensing means. For example, when the temperature sensing means 112 of the second group 102 is composed of three rows of four rows, five rows and six rows, the average temperature value of the temperature sensing means located in the fourth row and the fifth row is obtained, or the fifth row and the sixth row. The average temperature value of the temperature sensing means located in the column is obtained.

Subsequently, the controller 190 calculates the temperature deviation by subtracting the average temperature value of the second group 102 from the average temperature value of the first group 101 and then stores the calculated temperature deviation together with the measurement time information. Save it temporarily).

Here, the controller 190 may repeatedly obtain at least one or more times the average temperature value of the first group 101, the average temperature value of the second group 102, and the temperature deviation thereof for a set time, and repeatedly The average value of the obtained temperature deviations and the preset reference value are compared with each other to diagnose whether the solidification shell 81 is cracked for each row.

The controller 190 may display the average deviation value LPI of any row calculated within the set unit time N on the display unit 150 as a time axis as illustrated in FIG. 6.

)이 10으로 설정되어 있으며, 제어부(190)는 편차 평균값(LPI)이 10을 초과할 경우에 몰드(30)내 응고쉘(81)에 면세로 크랙이 발생한 것으로 진단한다. 여기에서, 기준값(

)은 온도감지수단(111, 112)이 설치된 각 행별로 다를 수 있다.In FIG. 6, the y-axis is a calculated average value of deviations per unit time N for any row, and is a longitudinal probability index (LPI), and the x-axis is a time axis. In the embodiment of the present invention as shown in FIG.

) Is set to 10, and the control unit 190 diagnoses that cracks occur in the solidification shell 81 in the mold 30 in a duty-free manner when the deviation average value LPI exceeds 10. Where the reference value (

) May be different for each row in which the temperature sensing means 111 and 112 are installed.

)을 초과할 경우에는 도 7에 도시된 바와 같이 몰드 장변(31)의 중앙부, 즉 제2 그룹(102)에 위치된 응고쉘(81)에서 면세로 크랙이 발생된 것으로 진단한다. 만일, 1행 5열과 6열 사이에 위치된 응고쉘(81)에 크랙이 발생될 경우, 제15 센서와 제16 센서에서 검출된 몰드(30)의 온도는 4열에 위치된 제14 센서에서 검출된 몰드(30)의 온도보다 낮게 된다. 본 발명에 의한 크랙 진단 알고리즘은 도 7과 같이 크랙이 제2 그룹(102)의 온도감지센서 사이에서 발생될 경우에 크랙 검출 성능이 상대적으로 뛰어난 방식이다.That is, the mean deviation (LPI) is the reference value (

7), it is diagnosed that cracks are generated vertically in the solidification shell 81 located in the center of the mold long side 31, that is, the second group 102, as shown in FIG. If a crack occurs in the solidification shell 81 positioned between the first row, the fifth column, and the sixth column, the temperature of the mold 30 detected by the fifteenth sensor and the sixteenth sensor is detected by the fourteenth sensor located in the fourth column. Lower than the temperature of the mold 30. The crack diagnosis algorithm according to the present invention has a relatively excellent crack detection performance when cracks are generated between the temperature sensors of the second group 102 as shown in FIG. 7.

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

Deviation calculator 191 is the temperature detected by the temperature detection unit 110, each row in the average temperature value of the temperature sensing means 111 located in the first group 101 and the second group (102) Obtaining the average temperature value of the remaining temperature sensing means except for any one of the temperature sensing means 112, respectively, and between the obtained average temperature value of the first group 101 and the average temperature value of the second group 102 Calculate the temperature deviation. Of course, the deviation calculator 191 periodically obtains the average temperature value of the first group 101 and the average temperature value of the second group 102 to obtain a temperature deviation, and then temporarily stores the temperature deviation in the memory 130 together with the measurement time information. Can be stored.

The deviation average calculator 193 reads the temperature deviations repeatedly acquired for a predetermined time from the memory 130 and calculates an average value of the temperature deviations per set time.

The crack determination unit 195 compares the average value of the temperature deviations calculated by the deviation average calculation unit 193 and a preset reference value to diagnose whether the solidification shell 81 is cracked for each row.

The controller 190 may display the average value of the temperature deviations calculated by the deviation average calculator 193 on the display unit 150.

On the other hand, the control unit 190 at the temperature detected by the temperature sensing unit 110, the average temperature value of the temperature sensing means 111 located in the first group 101 for each row and the second group 102 Obtain the average temperature value of the remaining temperature sensing means except for any one of the temperature sensing means 112 located at, and determine the temperature deviation between the obtained average temperature value of the first group and the average temperature value of the second group. Save with. Here, the controller 190 may repeatedly obtain at least one or more times the average temperature value of the first group 101, the average temperature value of the second group 102, and the temperature deviation thereof for a set time, and repeatedly The average value of the obtained temperature deviations is collected for the set unit element time. The deviation average value may be collected for a unit element time, and the maximum fluctuation range of the collected deviation average values and the predetermined threshold value may be compared with each other to diagnose whether the solidification shell 81 is cracked for each row.

In addition, the controller 190 repeatedly acquires the average temperature value of the first group 101, the average temperature value of the second group 102, and the temperature deviation of each row at least once for a set time, and repeats each row. The solidification shell may be diagnosed by comparing the maximum average value among the average values of the temperature deviations for each row and the preset reference value.

8 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.

9 shows the temperature of the mold at a specific time point, and shows the temperature of the mold 30 detected by the temperature sensing means 111 and 112 located in one row, two rows, and three rows at a specific time point.

As shown in FIG. 9, 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 temperature measurement time T is set (S13), the controller 190 controls the temperature sensing means 111 corresponding to the first group 101 existing in an area where a crack does not occur in an arbitrary row. The average temperature value of the temperature sensing means 111 located in the first group 101 is calculated using the temperature information (S14).

The controller 190 calculates an average temperature value for the first group 101, and then among the temperature sensing means 112 of the second group 102 existing in an area where a crack occurs in an arbitrary row. The average temperature value of the remaining temperature sensing means other than one is calculated (S15).

The controller 190 calculates the temperature deviation by subtracting the average temperature value of the first group 101 and the average temperature value of the second group 102 obtained above, and stores the calculated temperature deviation together with the measurement time information. Temporarily stored in 130 (S16). In this case, the controller 190 may display the calculated temperature deviation on the display unit 150 on a time axis.

Subsequently, the controller 190 determines whether the set unit time (N or number of times) has elapsed (S17). If the set unit time has not elapsed, the control unit 190 repeats the above processes (S14 to S16) and the first group ( The average temperature value of 101), the average temperature value of the second group 102, and the temperature deviation thereof are obtained again, and the obtained temperature deviation is temporarily stored in the memory 130 together with the measurement time information.

This process is repeated for a set unit time (N).

)을 상호 비교하여 각 행별로 응고쉘(81)의 크랙 여부를 진단하게 된다(S19). 여기에서, 제어부(190)는 온도편차들의 평균값이 기준값(

) 이상일 경우에는 응고쉘(81)에 크랙이 발생한 것으로 진단한다. When the set unit time (N, or unit number of times) elapses (S17), the controller 190 reads repeatedly obtained temperature deviations from the memory 130, calculates an average value of the temperature deviations (S18), and calculates the calculated deviations. Average value and preset reference value (

) To diagnose the crack of the coagulation shell (81) for each row (S19). Herein, the controller 190 determines that the average value of the temperature deviations is a reference value (

) Is diagnosed as a crack has occurred in the solidification shell (81).

In this case, the controller 190 may display the average deviation value for any row calculated within the set unit time N on the display unit 150 as a time axis as illustrated in FIG. 6.

On the other hand, it is also possible to diagnose whether the solidification shell is cracked by comparing the maximum average value and the predetermined reference value among the average values of the temperature deviations of the respective rows repeatedly obtained in S12 to S18.

10 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 measuring time T is reached (S23), the controller 190 controls the temperature of the temperature sensing means 111 corresponding to the first group 101 existing in an area where no crack is generated for each row. The average temperature value of the temperature sensing means 111 located in the first group 101 is calculated using the information (S24).

The controller 190 calculates an average temperature value for the first group 101, and then selects any one of the temperature sensing means 112 of the second group 102 existing in an area where cracks are generated for each row. Calculate the average temperature value of the remaining temperature sensing means except for one (S25).

The controller 190 calculates a temperature deviation by subtracting the average temperature value of the first group 101 and the average temperature value of the second group 102 obtained for each row, and calculates the calculated temperature deviation by measuring the time information. Temporarily stored in the memory 130 together with (S26). In this case, the controller 190 may display the calculated temperature deviation on the display unit 150 on a time axis.

Subsequently, the controller 190 determines whether the set unit time (N, or number of times) has elapsed (S27). If the set unit time has not elapsed, the control unit 190 repeats the above steps (S22 to S26) and the first group ( The average temperature value of 101), the average temperature value of the second group 102, and the temperature deviation thereof are obtained again, and the obtained temperature deviation is temporarily stored in the memory 130 together with the measurement time information.

This process is repeated for a set unit time (N).

When the set unit time (N, or unit number of times) elapses (S27), the controller 190 reads the repeatedly obtained temperature deviations from the memory 130, calculates an average value of the temperature deviations, and stores the calculated deviation average value in the memory. Temporarily stored in 130 (S28).

The controller 190 may display the average deviation value calculated within the set unit time N on the display unit 150 as a time axis as illustrated in FIG. 11.

Subsequently, the controller 190 determines whether the set unit element time Te has elapsed (S29). If the unit element time Te has not elapsed, the control unit 190 repeats the processes (S22 to S28) and temperature deviations. The average value for is collected repeatedly.

The deviation mean values are collected during the unit element time Te, and if the unit element time Te has elapsed, the maximum variation range D _T is obtained by using the maximum value T _max and the minimum value T _min of the collected deviation mean values. After the calculation, the calculated maximum fluctuation range D _T and the preset threshold are compared with each other to diagnose whether the solidification shell 81 is cracked (S30). Here, the controller 190 diagnoses that a crack has occurred in the solidification shell 81 when the maximum fluctuation range of the temperature deviations is greater than or equal to the threshold value.

In FIG. 11, the y-axis is a calculated average value of deviations per unit time N for any row, and is a longitudinal probability index (LPI), and the x-axis is a time axis.

In general, the length of the strand 80 withdrawn from the mold 30 may be about 0.9m to 2.3m per minute (min), based on the unit element time Te is set in the range of 15sec to 150sec Can be. Here, when the unit element time Te is 15 sec or less, a large crack cannot be detected, and when the unit element time Te is 150 sec or more, a temperature deviation irrelevant to the crack may be generated, which may lower accuracy.

The unit time N or the number of times and the unit element time Te are different reference information, and the unit element time Te is set to a larger value than the unit time N.

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 between the temperature sensing means located in the second group.

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: deviation calculation unit 193: deviation average calculation unit
195: crack determination

Claims (20)

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
In the temperature detected by the temperature sensing unit, the average temperature value of the remaining temperature sensing means except for any one of the average temperature value of the temperature sensing means located in the first group and the temperature sensing means located in the second group for each row A control unit for acquiring cracks for the solidification shell discharged from the mold by using the temperature deviation between the respective acquired and obtained average temperature values of the first group and the average temperature values of the second group. Crack diagnosis device for solidification shell.
The method according to claim 1,
The first group includes at least one temperature sensing means located in an area where no cracking occurs, and the second group includes at least one temperature sensing means located in an area where the cracking occurs. Crack Diagnosis Device.
The method according to claim 1,
And the remaining temperature sensing means of the second group is a temperature sensing means adjacent to each other.
The method according to claim 1,
And the control unit repeatedly acquires the average temperature value of the first group, the average temperature value of the second group, and the temperature deviation for each row at least once for a set time.
The method of claim 4,
The control unit is a crack diagnosing apparatus of the solidification shell in the mold for diagnosing the cracking of the solidification shell by comparing the average value of the temperature deviation for each row repeatedly obtained with a predetermined reference value.
The method of claim 4,
The control unit repeatedly collects the average values of repeatedly obtained temperature deviations for a set unit element time, and compares the maximum fluctuation range with respect to the collected average temperature deviation values and a preset threshold value to diagnose whether the solidification shell is cracked. Crack diagnosis device for solidification shell in mold.
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,
Wherein said temperature sensing means is any one of a thermocouple and a temperature sensing means.
The method according to claim 1,
The plurality of temperature sensing means is crack cracking apparatus of the solidified shell in the mold is embedded in the matrix form on the upper side of the mold long side.
The method according to claim 1,
The control unit,
In the temperature detected by the temperature sensing unit, the average temperature value of the remaining temperature sensing means except for any one of the average temperature value of the temperature sensing means located in the first group and the temperature sensing means located in the second group for each row A deviation calculator for obtaining each and calculating a temperature deviation between the obtained average temperature value of the first group and the average temperature value of the second group;
A deviation average calculation unit repeatedly obtaining the temperature deviation for a predetermined time and calculating an average value of the repeatedly obtained temperature deviations; And
And a crack determination unit for diagnosing whether the solidification shell is cracked by comparing the average value of the temperature deviations calculated above with a predetermined reference value.
A plurality of temperature sensing means arranged in a matrix in the mold, the mold temperature being detected for each row;
Calculating an average temperature value with respect to the detected temperature from the temperature sensing means existing in a region where cracks do not occur for each row at the detected mold temperature;
Calculating an average temperature value of the temperature sensing means except for any one of the temperature sensing means existing in a region where cracks are generated in each row at the detected mold temperature; And
Calculate the temperature deviation between the average temperature value of the first group and the average temperature value of the second group for any row obtained above, and use the calculated temperature deviation to determine whether cracks have occurred for the solidification shell discharged from the mold Diagnosing a crack of the solidified shell in the mold comprising a.
The method of claim 12,
The method for diagnosing cracks in a solidification shell in a mold, wherein the average temperature value of the first group, the average temperature value of the second group, and the temperature deviation are repeatedly obtained at least one time for a predetermined time for each row.
The method according to claim 13,
The diagnosing step may include cracking the solidified shell in the mold to diagnose whether the solidified shell is cracked by comparing the average value of repeatedly obtained temperature deviations with a predetermined reference value.
The method according to claim 13,
The method of diagnosing cracks in the solidification shell in the mold for diagnosing whether the solidification shell is cracked by comparing the maximum average value and the predetermined reference value among the average values of the temperature deviations of each row repeatedly obtained.
The method of claim 12,
The diagnosing step is
Obtaining a temperature deviation by subtracting the average temperature value of the first group and the average temperature value of the second group obtained above;
Repeatedly acquiring the temperature deviation for a predetermined time and calculating an average value of the repeatedly obtained temperature deviations; And
And diagnosing whether the solidification shell is cracked by comparing the average value of the temperature deviations calculated above 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.
The method according to claim 13,
In the diagnosing step, the average value of repeatedly obtained temperature deviations is repeatedly collected for a set unit element time, and whether the solidification shell is cracked by comparing the maximum variation range and the predetermined threshold value with respect to the collected average temperature deviation values. Crack diagnostic method of the solidified shell in the mold to diagnose the.
The method according to claim 18,
The unit element time is a crack diagnostic method of the solidified shell in the mold is set in the range of 15sec to 150sec.
The method of claim 12,
The diagnosing step is
Obtaining a temperature deviation by subtracting the average temperature value of the first group and the average temperature value of the second group obtained above;
Repeatedly acquiring the temperature deviation for a predetermined time and storing the average deviation value of the repeatedly obtained temperature deviations;
Collecting the deviation mean value repeatedly for a set unit element time and calculating a maximum variation using the maximum and minimum values of the collected deviation mean values; And
And diagnosing whether the solidification shell is cracked by comparing the calculated maximum variation with a predetermined threshold value.

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