TW200946265A - Method for detecting breakouts in continuous casting and an apparatus therefor, breakout prevention apparatus, method for estimating solidification shell thickness and an apparatus therefor, and a continuous casting method for steel - Google Patents

Abstract

Disclosed is a method and an apparatus for detecting breakouts in continuous casting and an apparatus therefor, for precisely detecting breakouts that occur in slabs during the continuous casting of molten steel, wherein: a heat flux q1 of heat input to the solidification interface from when the molten steel in the mold is at bath level to when it reaches the mold exit, is measured; a steady solidification interface heat input q2reg, caused by the flow of molten steel in mold in a steady state, is obtained based on the formula below (1); a heat flux profile is obtained for the difference between heat flux q1 and the steady solidification interface heat input q2reg (q1-q2reg) from when the molten steel is at bath level to when it reaches the mold exit; and whether a breakout occurred and whether the breakout is due to resolubility or heat extraction deficiency, is determined, based on the heat flux profile. q2reg=h*Δθ (1) Where: h = heat transfer coefficient between molten steel and solidification shell; and *Δθ = degree of superheat of molten steel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for accurately detecting a breakout generated on a cast piece in continuous casting of molten steel, thereby preventing the casting. Further, the present invention relates to a continuous casting method of steel using the above-described casting leakage detecting method. Furthermore, this is also a method and apparatus for estimating the thickness of the solidified clam shell in the continuous restraint of steel making. [Prior Art] Yulian, β-cast 4 towel's, after forming a solidified shell by cooling the molten steel injected into the mold to form a solidified shell, it is drawn from the mold, but if it is solidified for some reason If the formation of the shell is insufficient, and there is a portion where the solidified shell is thin, there is a danger of simplification, that is, when the portion of the front shell is thin, the solid shell is broken when the mold exit (the lower end of the die) And lead to refining _ out. If a casting leak occurs on the right, the operation must be stopped. Therefore, it is necessary to select an operation ride that does not cause a prayer, but the material (4) (10) leakage (four) is converted to a low casting speed, which may result in deterioration of operation efficiency, which is not preferable. Based on this background, it is desired to develop a method of accurately shutting off the shaft even if it is made in a high degree of manufacture. Various methods have been proposed at present. For example, the following technique is disclosed in Patent Document 1 (Japanese Patent Publication No. Sho 39 No. 3). The technique is a method for preventing leakage of continuous casting, which is a sheet-type surface heat flux meter disposed on the outer surface of a mold of 098106495 3 200946265, and f corresponds to a heat extraction 〇f mold of the mold. The heat flux is measured and leaked. The continuous casting of the pound leaker; characterized by: by a majority: pass two: to determine the local heat flux of each part of the mold, when the heat flux waveform indicating the temporal change of the heat flux is irritatingly When the value exceeds a predetermined value, the scale is reduced, and the degree is lowered until the wave height is restored to the original state, thereby preventing the production 2. [Inventive content] (Problems to be solved by the invention) ® The technique disclosed in Patent Document 1 uses a heat pass A method for preventing leakage of the heat flux detected by the meter. The local heat flux of each part of the die means that the heat rejection from the die is related to the formation of the solidified shell. Therefore, = / is roughly reasonably predicted that when the change in the heat flux causes an abnormality, the formation of the solidified shell thickness causes an abnormality, and there is a risk of casting leakage. However, considering the exit of the mold, if the thickness of the solidified shell does not reach the thickness of the predetermined crucible, the casting leakage is caused by the change of the heat flux, and the risk of accurate leakage may not be sufficiently grasped. The reason for this is that there is also a case where there is an abnormality in the heat flux in the initial stage of the solidified shell forming process in the mold, as long as a solidified shell is formed in the stage after the solidification forming process, and both are formed at the exit of the cast mold. The solidified shell of the thickness of the crucible can judge the danger of no scale leakage. That is, it is predicted by the change of the local heat flux shown in the previous example that the risk of casting leakage is 098106495 4 200946265, which is difficult enough to be an accurate indicator. As described above, the generation of the scale leakage is directly related to the thickness of the solidified shell at the exit of the prayer mold. If the thickness of the solidified shell can be accurately estimated, the risk of casting leakage can be judged with high precision. That is, the inventors believe that it is important to find out the fact that the thickness of the solidified shell at the exit of the die has been closely related to the fact that the thickness has reached a predetermined thickness. Therefore, the object of the present invention is to provide a continuous prayer in the steel. A method and apparatus for detecting the casting leakage generated on a cast piece with high precision and preventing the casting leakage. Another object of the present invention is to provide a method and apparatus for estimating the thickness of a solidified shell at the exit of a mold with higher precision. * (Means for Solving Problems) < Investigation and Analysis of Phenomena> The thickness of the solidified shell is closely related to the heat removal state between the pound mold and the cast piece. That is, if the thickness of the solidified shell is thin, the amount of heat transfer from the transfer mold increases, and the amount of heat is increased. On the contrary, if the thickness of the solidified shell is thick, the amount of heat transferred from the prayer sheet to the scale mold is reduced, resulting in heat rejection. cut back. In order to study this fact in more detail, the inventors conducted a check on the specific heat-discharging state in the actual mold. . ' $ For detecting the heat exhaustion 11, the heat flux of each part must be obtained in the following manner. Figure 2 is a cross-sectional view of the mold 1 showing the mouth of the dip nozzle (immersi〇n fiber) which is attached to the bottom of the groove 4 and is placed in the die 1 (the ink nozzle 098106495 200946265 steel 5 (arrow) status. Molded powder 7 (shown as a layer) is added to the surface of the furnace bath, and the molded powder 7 flows into the gap between the mold 1 and the molten steel 5 to function as a lubricant. The molten steel 5 is discharged to the mold 1 via the molded powder 7, and the solidified shell 9 is formed while being drawn toward the exit of the mold. Fig. 3 is a cross-sectional view showing a part of the mold copper plate 11 forming the mold 1 in an enlarged manner. In order to obtain the heat flux, the temperature gradient of the mold copper plate 11 must be detected, and the thermocouple 17 is used to detect the temperature gradient. As shown in Fig. 3, a hole 15 is formed in the bottom of the cooling water passage 13 formed on the outer side of the mold copper plate 11, and the above-mentioned thermocouple 17 is buried in the hole 15 at two locations separated by a fixed distance in the depth direction. The temperature gradient can be detected based on the output of the buried thermocouple 17, and the heat flux can be calculated by calculation based on the temperature gradient. The detection temperatures of the two thermocouples 17 are set to T1 (°C) and T2 (°C), the embedding interval is set to d(m), and the thermal conductivity of the mold 1 is set to; I (J/sw °C), the local heat flux ql (J/s · m2) is calculated by the following equation. Ql= λ (Tl-T2)/d In the investigation of the inventor, for example, in the case of the short side of the mold (in the mold of the horizontal section growth cube, the shorter side), the black dot mark of Fig. 4 It is shown that a pair of thermocouples composed of two thermocouples 17 provided in the thickness direction of the mold are disposed at a total of nine locations at a height of 40 to 200 mm at a position lower than the position of the normal bath surface. Based on the output signals from the thermocouples 17, and the local heat flux was obtained by the above equation, the relationship between the heat flux of the 098106495 6 200946265 portion and the position of the bath surface was investigated. Fig. 5 is a graph showing an example of the results of the investigation, in which the vertical axis represents the local heat flux (unit: J/s · m2), and the horizontal axis represents the distance from the bath surface (unit: coffee). In addition, in the present specification, the shape of the following chart is referred to as a heat flux distribution, and the graph shows the vertical heat flux as a local heat flux and the horizontal axis as a distance from the bath surface to indicate local heat flux and distance. A graph of the relationship between the distances of the bath surfaces. As shown in the graph of Fig. 5, the local heat flux decreases from the furnace bath surface toward the mold exit direction, and a minimum value is obtained at a distance of 400 mm from the bath surface, which then shows a tendency to increase temporarily, which increases. It tends to show a maximum value near the bath surface at a distance of about 600 mm, and then decreases again. The inventors paid attention to the tendency of the local heat flux to decrease from the direction toward the exit of the mold to become a transient rise, and further studied it. The position where the local heat flux shows a minimum value is the distance from the bath surface ^ 400 ,, which is the ejected flow of the e-melting steel 5 ejected from the discharge port of the self-immersion nozzle 3 (flow from the Spout: arrow) The position of the short side of the impact die is the same (refer to Figure 2). The relationship between this change in local heat flux and the discharge of the Hyungang steel illustrates the following. • As shown in Fig. 5, the local heat flux decreases as it goes from the furnace bath surface toward the scale die exit direction. This indicates an increase in thermal resistance. That is, as shown in Fig. 2, the solidified shell thickness gradually increases. Then, it can be considered that the position at which the ejected stream of the molten steel 5 ejected from the dip nozzle 3 impinges on the solidified shell 9 causes re-melting of the solidified shell 9, and the solidified shell thickness is reduced by 098106495 7 200946265 degrees by the molten steel. The heat generated by the flow is applied to the solidification interface of the thinned solidified shell 9, resulting in an increase in local heat flux. Moreover, it can be said that as the further progress toward the direction of the pound, the influence of the flow of the molten steel disappears, and the local heat flux decreases again, so that the solidified shell thickness becomes thicker. According to the above research, it can be considered that the shape of the solidified shell 9 at a certain moment is as shown in Fig. 2, and the thickness of the solidified shell 9 is increased from the position of the furnace bath surface to the minimum value of the local heat flux. The thickness of the solidified shell 9 is reduced from the minimum value of the heat flux to the maximum value, and further, the thickness of the solidified shell 9 increases again after the maximum value of the local heat flux. In the mold, the thickness of the solidified shell at the exit of the mold is determined by the process of thickening or thinning the thickness of the solidified shell in the above manner. It is considered that the relationship between the degree of growth of the solidified shell thickness and the degree of thinning of the solidified shell 9 which is temporarily formed by refining of the solidified shell 9 in the mold is directly related to the thickness of the solidified shell at the exit of the mold. Further, considering that the occurrence of the casting leakage is related to the thickness of the solidified shell at the exit of the mold, it is considered that the relationship between the above two degrees is closely related to the presence or absence of casting leakage. Therefore, the inventors have further studied in order to investigate the relationship between the above two degrees, that is, the degree of growth of the solidified shell thickness and the degree of thinning of the temporarily formed solidified shell 9 and the occurrence of leakage. <Introduction of solidification interface heat input> It is assumed that the solidified shell is not melted by the molten steel flow in the mold. 098106495 8 200946265 For example, the molten steel flow is not ejected from the impregnation nozzle and only extracted. When the molten steel in the scale mold is 4, the thickness of the solidified shell will gradually increase from the furnace bath surface toward the scale die exit. ::: A state in which the distance from the solidified shell caused by the molten steel flow is as described above, and it is assumed that the horizontal axis is the same as the partial heat flux from the furnace surface as shown in Fig. 5 A steady reduction curve of midway rise observed when not in the case of Fig. 5 was formed. Φ = two is the case where the thickness at the exit of the mold of the solidified shell is proportional to the value obtained, and if it is such a hypothetical condition, the heat flux distribution of the above chart is taken as the generation 铧The indicator of leakage. When the main mold is used in reality, the following wire is produced: the molten steel flow (hereinafter referred to as "melted steel flow") generated by the jet flow from the immersed iron: = and the re-melting of the solidified shell is formed. 9 is thinned by the remelting, and at the same time, the amount of heat removal is increased. Pb 'is considered that in the presence of the influence of the molten steel flow, the degree of the thickness of the shell is not only proportional to the amount of heat discharged, but also to the amount of heat exhausted from the actual heat; the heat generated by the sound of the Ί & The value is proportional. The heat rejection # generated by the influence of the steel flow can be evaluated as a molten steel flow for the solidification boundary (hereinafter simply referred to as "solidification interface heat input"). • V 4, b This consideration can be used to evaluate the degree of thinning of the solidified shell by the suspected solid interface heat input in the working state of the molten steel from the impregnation nozzle, and the other aspect can be determined by The local heat flux measured by the thermocouple minus the heat input obtained from the solidification interface is used to evaluate the extent of gambling growth. 098106495 9 200946265 Therefore, it is possible to set an index for casting leakage by performing a comparative study on the two evaluation amounts. However, if the heat input to the solidification interface is set to q2 (J/s · m2), the heat transfer coefficient of the self-melting steel toward the solidification interface is h (J/s · m2 · °C), and the superheat of the molten steel is obtained. When Δ0 (°C) is set, the solidification interface heat input q2 can be expressed by the following formula. Q2 = h · Δ ^ ... (1) where h = 1.22xl05xV°8 V : molten steel flow rate (m/s) ΑΘ = T〇-Ts (°C) τ〇: mold Inner molten steel temperature (°c)

Ts: molten steel solidus temperature (°c) In addition, for the molten steel temperature T〇(°C) in the mold, the molten steel temperature in the mold can be actually measured, for example, according to the feed tank (TD) melting The steel temperature (measured value) was calculated by the following equation for estimating the molten steel temperature in the mold. T〇= 705. 156+ 0. 544086 · Ttd-2. 35053 · Vc- 0. 00303 · W + 18. 12663 · (0. 10181nFC- 0. 3362) where Ttd : TD inner molten steel temperature (°C ) (measured value)

Vc : casting speed (m/min) W : casting width (m) (measured value) FC : applied current value (A) (measured value) As described above, the solidification interface heat input q2 is related to the heat transfer coefficient h The amount, and the heat transfer coefficient h is the amount related to the steelmaking flow rate V. Therefore, 098106495 10 200946265 In order to measure the solidification interface heat input q2 on-line, the molten steel flow rate V in the mold must be measured online. However, it is difficult to measure the molten steel flow rate V 在线 in the working state. Therefore, the inventors considered a method of sampling a cast piece cast at various casting speeds in advance, and calculating the dendrite angle of the cast piece. The melt flow rate value of each casting speed is obtained, and the solidification interface heat input q2 based on the molten steel flow rate value is obtained. Here, the dendrite angle refers to the inclination of the first branch of the dendrite extending from the surface toward the thickness direction with respect to the normal direction. The normal direction is relative to the normal direction of the surface of the cast piece. The dendrite angle is related to the melt flow rate value. The previously obtained solidification interface heat input q2 is referred to as "stabilized solidification interface heat input q2", and is referred to as a stable solidification interface heat input. Further, the purpose of using a material called a crucible state is to ride an obstacle such as a clogging in a dipping nozzle, and an abnormal state such as a drift in a tank flow rate. ® Then the 'inventor considered the following method: to estimate the local heat flux measured by the thermocouple minus the stable solidification when it is desired to estimate the thickness of the solidified shell at the exit of the mold or to evaluate whether or not there is a casting leak. The interface heat input ". and the age of the cake, the heat flux distribution is obtained, and according to the distribution of the occupational flux, the solidified shell thickness at the exit of the price casting mold or the presence or absence of a pray leak is considered. Consider the local heat measured by the above method. The reason for the flux minus the heat input at the stable solidification interface is as follows: The local heat flux actually measured in the field and the self-operating state minus the heat-related heat flux obtained by the stable interface 098106495 11 200946265 solid interface heat input q2ree When the quantity distribution becomes a curve of steady reduction, it is indicated that the heat flux distribution is the same as the heat flow rate distribution when the molten steel is not discharged from the impregnation nozzle and only the molten steel in the mold is extracted. This indicates solidification in the working state. The interface heat input q2 is the same as the stable solidification interface heat input q2reg. That is, in the case of this state, the degree of solidification of the solidified shell is generally the same as that from the impregnation nozzle. The flow is caused to the same extent 'that is the same as the steady state. If this is the case, as long as the cooling of the mold is carried out as usual, the 'solidified shell grows as usual' can be evaluated as not producing a casting leak. The condition can be based on the heat flux distribution associated with the heat obtained from the actual measured local heat flux minus the steady solidification interface heat input q2reg, and the thickness of the solidified shell at the exit of the mold is estimated. When the solidification interface heat input q2 is the same as the stable solidification interface heat input q2reg, it is said that the following casting leakage (hereinafter referred to as "re-dissolving scale leakage") does not occur. The casting leakage system is due to the solidification interface heat input q2. The increase causes the solidification interface to be re-dissolved, but even in this case, during the period from the molten steel moving from the meniscus to the lower end of the mold, the heat generation which contributes to the growth of the solidified shell thickness is small, when the solidified shell When the thickness is not sufficiently increased during the movement, the amount of heat generated by the growth of the solidified shell thickness is small (hereinafter referred to as " The danger of insufficient heat exhaustion. On the other hand, when the heat flux associated with the local heat flux measured from the use of the thermocouple minus the heat input from the stable solidification interface heat input q2reg is 098106495 12 200946265 'the position of the face is at a distance from the distance When rising, that is, if the heat flux distribution has a pole value of j and can form a convex portion, it means that the actual solidified interface hot rim 2 is larger than the stable condensed 111 interface heat input q2reg, and it is considered that in this state, the condensation port <The remelting degree is stable. For example, in the scale mold, the molten steel flow is biased due to clogging of the reverse nozzle, and the heat wheel ratio of the mold interface to be measured is generally increased. (4) The size of the convex portion of ItM' (4) indicates that the hot wheel person is larger than the normal solidified ❿ interface heat input person q2. That is, the following evaluation can be made: the convexity. The greater the degree of the P-knife is the degree to which the solidified shell is remelted due to the abnormal steelmaking flow, and the thickness of the solidification is reduced. When the degree is large, even if the tungsten mold is cooled in the usual manner, There is a risk of producing remelting slips. In this way, the heat flux distribution associated with the heat obtained from the actual localized heat flux minus the steady solidification interface heat input q2reg is obtained, whereby the W portion (four) convex in the heat flux distribution can be determined. The degree of the size of the part is 'clearly grasped and the steady state minus the degree of re-rotation of the solidified shell, and the thickness of the shell of the (four) exit at the exit of the mold can be estimated, and at the same time, the re-darkness can be evaluated according to the thickness The danger of sexual prayer. Further, by removing the heat of heat removal from the convex portion by the second step, it is also possible to evaluate the risk of generating an exhaustion-deficient pound leak. <Importing of total heat fluxes Q1 and Q2> Therefore, the inventor obtained the molten steel money according to the dip angle of the decidation angle of 098106495 13 200946265 for the various scales, and the stability of the interface was obtained. The heat input q-2reg' is calculated from the heat dissipation of the Lily galvanic couple in the residual state minus the heat input q2reg of the stable solidification interface, and the heat flux distribution is determined according to the distribution of the solid flux to estimate the thickness of the solidified shell. Further progress is made to study whether or not there is a pound leak. The contents of this study will be specifically described below. Figure 6 shows the flow rate of the molten steel as the vertical axis and the distance from the bath surface as the horizontal axis. Under the condition of casting speed Vc=2.54 m/min and tungsten manufacturing width W=1, the dendrites according to the cast piece Inclination* Find a graph of the relationship between the melt flow rate (m/s) and the distance from the bath surface (mm). From the chart, the molten steel flow rate V (m/s) is obtained, and the stable solidification interface heat input q2 "g is obtained according to the above formula (1). Then the 'hot thermocouple pair local heat flux 4 in the operating state is secreted. The shape of the self-test is the same as the steady-state solidification interface under the pound-making speed, and the heat flux distribution obtained after subtraction is obtained. g The vertical axis of Figure 7 indicates local heat. Flux U/s · m2), the horizontal axis represents the distance from the bath surface (_, again, the value of the black circle in the graph (Dl) indicates the measured value measured by the 孰 couple, the value of the white circle (10) indicates The measured value obtained by the thermocouple minus the value obtained by the stable solidification interface heat input q2reg (ql —

Figure 8 is a diagram of _矣, BT of Figure BT, which is schematically represented by a white circle in Figure 7 (a diagram of the heat flux distribution of dl - which is the area enclosed by the graph, that is, the local mirror amount Explanation of the cumulative value (, _ flux) - an example of the description of 098106495 14 200946265. Hereinafter, the method of calculating the total heat flux will be described based on Fig. 8. First, as shown in Fig. 8, the graph is divided into plural numbers. The trapezoidal shape is used to obtain the area of each trapezoid (Q1-1 to Q1-7), and the area Q is obtained by adding the areas. Next, the minimum point in the graph is set to A, The maximum point is set to B, the point of the exit of the mold is set to C, and the triangle ABC is taken as a convex portion, and the area of the convex portion, that is, the area Q2 of the triangle ABC (see Fig. 9) is obtained as follows. If the point on the horizontal axis corresponding to the point A is A', the point on the horizontal axis corresponding to the point C is set to C', and the area Q1-8 of the trapezoidal ACC'A' is obtained, and the Q1 is obtained. -8 and the area obtained by adding Q1-1 to Q1-3 as Q1, then Q2 = Q - Q is obtained according to Q1 and Q2 obtained in the above manner, for each casting Under the conditions, φ The relationship between Q1 and Q2 and the presence or absence of casting leakage is studied. The results are shown in Table 1. Regarding the presence or absence of casting leakage, when the thickness of the shell reaches the threshold of 6 liters or less, it is judged as "Yes". Produce a casting leak. 098106495 15 200946265 [Table 1] Study Example Q1 Q2 Is there a casting leak (kJ/ra2) (kJ/m2) 1 19000 1200 No 2 17900 1450 No 3 25000 540 No 4 27000 1500 No 5 28000 3500 No 6 31500 5000 No 7 33500 8500 No 8 27500 6850 No 9 26000 10050 No 10 19500 3550 No 11 18900 4090 No 12 17800 3950 No 13 17900 4500 There are 14 19000 5700 There are 15 19070 5950 16 19450 7500 There are 17 20570 8500 There are 18 14000 1000 There are 19 13300 100 20 12500 1020 Μ 21 11700 1500 with 22 10500 3200 with 23 9750 1500 Μ 24 8050 300 25 7650 450 with 26 6500 270 with 27 5450 55 with 28 4890 150 Μ 29 14500 10800 with 30 13000 9000 Μ 31 12700 9500 32 10700 8000 with 33 10200 7500 with 34 9000 6000 with 35 7050 5500 36 8650 8200 with 37 7400 4500 with 38 5100 4700 39 7150 6800 with 40 6950 6500 In the coordinate plane where the horizontal axis is Q1 (kJ/m2) and the vertical axis is Q2 (kJ/m2), the values shown in Table 1 are plotted, and the casting leak is generated depending on the presence or absence of The relationship is divided into five areas to the table 098106495 16 200946265. The boundary line of the region is Ql(a 1)=15〇〇〇(kJ/m2), Q1(a2)== 21000(kJ/m2) &gt; Q2(yS ) = 45〇〇(kj/m2) 0 In the area shown in FIG. 10, the areas (1) to (3) are areas where there is a risk of pound leakage (ie, the area determined as "having" in the above investigation), the area (4), (5) It is an area where there is no danger of casting leakage. First, a comparative study was conducted on areas (丨)~(3) common to the risk of casting leakage. 〈 <Area (1)&gt; The area (1) (Q1&lt;αΐ and 2 calls) can be evaluated as the following area: Q1 is small and Q2 is large, and there is a danger of generating heat-exhaust leakage and generating The danger of melt-casting leaks is both. Further, since the casting leakage actually occurs in the region, it can be said that the casting leakage system has the properties of both the heat-dissipating casting leakage and the re-melting casting leakage. Further, if the state of the region (1) is considered from the viewpoint of the thickness of the solidified shell, the following portion is considered to be present, and the degree of thinning is large, and the thickness of the whole solidified shell is thinned due to the small Q1. And the thickness of the solidified shell is partially thinned due to the large q2. &lt;Zone (2)&gt; The area (2) (Q1 &lt; α 1 and Q2 &lt;cold) can be evaluated as the following area: the small area is small, and there is a risk of causing an exhaustion of the exhaust heat, but since it is small Therefore, the risk of re-refining pounds is small. Moreover, since the casting leakage actually occurs in the region (2), it can be said that the casting leakage system has the property of the heat-dissipating casting leakage 098106495 17 200946265. Furthermore, if the state of the region (2) is considered from the viewpoint of the thickness of the solidified shell, it is considered that the degree of thinning is small regardless of whether or not the following portion exists, and the thickness of the solidified portion of the portion is thinner due to the smaller Q1. However, the thickness of the solidified shell is partially thinned due to the small Q2. &lt;Zone (3) &gt; The area (3) (〇: lSQlSa2 and 卩22call) can be evaluated as the following area: Q1 is relatively large and there is less danger of causing insufficient heat-exhaust casting, but since Q2 is more Large, so there is a danger of remelting casting leakage. Further, since the casting leakage is actually generated in the region (3), it can be said that the casting leakage system has the property of remelting casting leakage. Further, if the state of the region is considered from the viewpoint of the thickness of the solidified shell, it is considered that the following portion exists and the degree of thinning is large, and the thickness of the whole solidified shell of the portion is relatively thick due to the large Q1, but the solidified shell is The thickness is partially thinned due to the large Q2. Secondly, a comparative study was conducted on the regions (4) and (5) where no casting leakage occurred. &lt;Zone (4) &gt; The region (4) (Q1 &gt; α2 and Q22/3) can be evaluated as the following region: Q1 is large and there is less danger of causing insufficient heat-extraction casting, but Larger, so there is a danger of remelting casting leakage. However, since no casting leakage occurs in this region (4), it can be considered that the heat generation amount which contributes to the growth of the solidified shell thickness is sufficiently large, so that even if the thickness of the solidified shell as a whole is thick, the partial condensation is 098106495 18 200946265 The thinning of the shell does not cause casting leakage. &lt;Zone (5)&gt; The region (5) (Q1 &gt; α 1 and Q2 &lt; call) can be evaluated as the following region: Q1 is relatively large and there is less risk of causing heat-exhaustion leakage, and due to Q2 It is small, so there is no danger of remelting casting. Moreover, the occurrence of the casting leakage in the region (5) is considered to be due to the amount of heat generated to contribute to the solidification of the shell thickness.

❹ is large, so the thickness of the solidified shell as a whole is thick, and there is no partial thinning of the solidified shell. Even if the solidified shell is thinned, the degree of thinning is small. From the above studies of the regions (4) and (5), it is understood that the state of the region (5) is more preferable if the state of the region (4) is compared with the state of the region (5). Therefore, when the state of the regions (1) to (3) where the casting leakage occurs is converted into a state in which no pound leakage occurs, the state of transitioning to the region (4) is also effective, but it is more preferable to control the operating conditions. To further transform into the state of the region (5). Specifically, when it is in the state of the region (1), the operating condition is performed as long as the state of the region (4) is changed by increasing the enthalpy, or the state of the region (5) is further decreased by Q2. Control can be. Further, when it is in the state of the region, the operation condition may be made as long as it is changed to the state of the region (5) by increasing the enthalpy. &amp; However, when in the state of the region (3), it is only necessary to control the operating conditions by changing the state of the region (5) by decreasing Q2 or changing the state of the region (4) by increasing qi. As a control for increasing the operating conditions of Q1, it is exemplified to reduce the speed of the assembly and/or to enhance the cooling of the mold. Further, as a control for reducing the operating condition of Q2, 098106495 19 200946265 exemplifies that the electromagnetic brake device is disposed, for example, in the upper and lower portions of the nozzle opening of the dip nozzle in the mold, and the flow rate of the molten steel is slowed by application of a DC magnetic field. Furthermore, the basic point of the method described above is to obtain the heat flux Q1 and the stable solidification interface heat input q2reg entering the solidification interface during the period from the furnace bath surface to the mold exit, and according to (ql) -q2reg) The heat flux distribution determines whether a casting leak will occur. Descriptions other than the above are exemplified and are not limited to the above. For example, the heat flux ql can be obtained from the temperature on the inlet side and the outlet side of the mold cooling water. Further, the stable solidification interface heat input Q2reg can be obtained from the result of the estimated value of the molten steel flow rate obtained by numerical simulation in the mold, for example. The analysis method of the heat flux distribution of (Ql - q2res) is preferably performed after calculating the above Q1 and Q2, but is not limited thereto. For example, the height and position of the raised portion may be simply used as a criterion for determining the risk of casting leakage (e.g., it is generally considered to be effective when the molten steel flow at the impact solidification interface is strong and the equipment is highly volatile). When using w1 and Q2 for analysis, if the minimum value and the convex portion are not generated in the heat flux distribution, it is sufficient to set == 8) and Q2 = 0. In the case where it is difficult to determine the minimum value of ql — q2reg (for example, the minimum value is unknown: the minimum value of two or more figures is present), as long as the approximate curve is drawn as close as possible to the pattern, From (ql - q2reg) drop curve (corresponding to the curve of Q1 in Figure 9, that is, the closer to the surface of the bath, 098106495 200946265, the curve of the local heat flux can be reduced by 0) becomes a minimum point Further, it is preferable to consider the thickness of the Q1 shell or to specify the casting leak. Face, and the change of Q2 is small. 4 Predictive accuracy and the accuracy of Q2 are both, but only Q1 can be used. For example, when it is expected that the molten steel flow does not easily reach the solidification boundary, even if Q2 is not considered, it is expected that when Q1 and Q2 are required, &lt; Integral means other than ❹ 法). The boundary line AC does not need to be a straight line. Of course, the method described above can also be used. (In addition, in the analysis of Fig. 9, Q1 and Q2, for example, the curve 4 from the bath surface to the A can also be considered. It is an approximation curve. Even when specific casting leak determination is performed using Q1 and q2, it is not limited to the above-described method, as long as Q1 is appropriately used as an index of heat generation caused by solidification (that is, by numerical value The factor of increasing the risk of casting leakage is to use Q2 as an indicator of the heat input exceeding the stable solidification interface (ie, the factor of increasing the risk of casting leakage by increasing the value ❹). Because there are many cases where the growth and solidification of the solidified shell thickness are not sufficient (Q1 &lt; α 1 of the above-mentioned area (1) and area (2)), and the growth of the solidified shell thickness Q2 is irrelevant and the case of casting leakage is sufficiently avoided (Q1 of the region (5) and the portion of the region (4) and the region (4)). Therefore, it is preferable to set the boundary of each boundary αΐ in advance. 'α 1 SQl S α 2 area becomes the shadow of the size In the area, it is determined that there is a risk of casting leakage based on the value of 卯. 098106495 21 200946265 That is, in the case of 'in this case', it is preferable that # is a predetermined threshold or more, and it is judged that there is a danger of _. Then, the threshold value of 2 is preferably determined according to W, but 'the final' can also be set to a fixed value for the whole of Ua2. The above table 1 is equivalent to the fixed value. - As another method' Consider further refining α^^ and setting the threshold in each-area. For example, when "3 butterfly α1&lt;α3&lt;α4&lt;α 2) 'in the case of Q1 &lt; α 3 is set, the point is set In order to correspond to the condition for generating the pound leak, in the case of α3_&lt;α4, the material corresponds to the condition for generating the casting leak, and in the case of α4_$α2, q = stone 3 is considered to correspond to the condition for generating the leak. Furthermore, in this case, usually β\&lt;β2&lt;β3〇in another 'in the region of alSQig α2, Q2^f((1)(f is a function) may also be used as a condition corresponding to the generation of the casting leak. For example, in the table In the case of 1 (15000 kJ/m2) to α2 (21_ kJ/in2) (Research Example 2, 10 17), Q22 can also be used. a Ql (α = 〇 · 25) criterion. In addition, 'depending on the equipment' can consider the following situation (the change of Q1 caused by the operating conditions, the car is small), etc.): not by αΐ, "2 and set the above boundary" and simply borrow * __ (α: for example, 〇 25) to determine the leak. Further, 'the upper limit is not set for Q1 and Q2 because the device corresponds to the device. The available values of Q1 and Q2 have their own upper limit. Furthermore, when the molten steel is ultra-low carbon steel (extra-l0w carb〇n steel) 098106495 22 200946265, the above-mentioned exemplified "the so-called molten steel is very low carbon steel." 〇._之钢. The basic part of α in the stage of the above-mentioned leakage core 1 is not dependent on 疋, and the analytical analysis of the formation phenomenon of the solidified shell is also possible. It is necessary to apply the coefficient or the threshold value to other steel grades. The inventor found that the values of qi and q2 are related to the occurrence of scale leakage and that each value is related to the cause of different casting leakage. By using the value of Q1 Q2 as an indicator of the occurrence of casting leakage, it is possible to detect the occurrence of scale leakage with high precision', and it is possible to appropriately control the risk of casting leakage according to the cause of casting leakage. Presumption of solidified shell thickness&gt; However, the total heat flux #Q1 obtained in the above manner can be evaluated as the heat of the molten steel solidification and the total heat flux Q2 can be evaluated as the molten steel flow impact solidification. The heat of re-dissolving of the solidified shell (ie, the steelmaking stream impacts sensible heat). That is, © if The total heat flux Q1 is used to estimate the thickness of the (four) shell at the σ of the mold, so that the thickness of the solidified shell can be estimated with high precision. Therefore, the solidified shell thickness is also determined according to Q1, and the tungsten is evaluated based on the solidified shell thickness. The possibility of the danger of leakage has been studied. The following is a description of the method for estimating the thickness of the solidified shell at the exit of the mold using the total heat flux Q1. First, if considering the physical process of solidification of the steel in the pound mold, The molten steel injected into the mold from the impregnation nozzle has the enthalpy of sensible heat and solidification: 仏 (including 098106495 23 200946265 heat). And 'the 熔:Ho molten steel loses heat due to heat release from the bath surface Part of the 焓: AHsur, again, during the period from the bath surface to the exit of the mold, cooling the town mold to remove heat, thereby losing the beginning of the equivalent of heat removal: ΔΗ (焓: enthalpy drop), finally At the exit of the mold, a solidified shell having 焓:乩 is extracted from the mold. If the relationship between the molten steel injected into the mold from the surface of the furnace to the exit of the mold is expressed by the formula, the following formula is used ( 4) Shows H〇 = Hi + AH + AHsur ......... (4) wherein 'H〇: enthalpy of molten steel within the mold (J / kg)

Hl : 凝固 (j/kg) of the solidified shell at the exit of the mold ΔΗ : the drop per unit weight of the solidified shell at the exit of the mold (J/kg) AHsur: the heat release from the bath surface (J/kg) Where, ΔΗμ, H〇 can be obtained in the following manner. &lt;Method for finding Hl&gt; 凝固: The solidified shell at the exit of the scale mold: IL can be obtained by the following formula (5).

Hi = 67〇. 27 Tiave+ 11958 (5) Equation (5) is obtained by integrating the specific heat of the steel of the solid phase with temperature and expressing it as a function of temperature. Into the formula. The Tuve in the formula (5) indicates the average temperature of the solidified shell at the exit of the prayer mold ((〇), which can be obtained by the following formula (6).

Tlave^28. 75 Vc+ 1234. 275 .........(6) where 'Vc: casting speed (m/min) 098106495 24 200946265 Equation (6) is Vc = 1. 4 m/min, 1. 8 m/min, 2.2 m/min, and 2. 6 m/min to calculate the heat transfer and solidification in the mold, and the average temperature of the obtained shell of the mold is expressed as the first order of Vc. . The map for the derivation of the equation (6) is shown in Fig. 11. The vertical axis of Fig. 11 indicates the average temperature (°C) in the thickness direction of the exit hole of the mold, and the horizontal axis indicates the casting speed (m/min). &lt;Method of Msur> Equivalent to the heat release from the surface of the hearth: AHsur can be obtained by the following formula 7 (7). AHsur= (10000/7100) · (60/Vc) ... (7) where Vc: casting speed (m/min) Equation (7) calculates the heat release from the bath surface That is, calculate how many defects are released per unit volume of molten steel. If the enthalpy released by the bath surface per unit area is set to ΔΗμ' (unit: W/m2), the AHsurCJ/kg of molten steel per unit volume is simply divided by AHsur' by unit time. The casting speed is determined by the speed of the steelmaking, so AHsur^ AHsur' / (density 7100 x Vc / 60xl (= unit area)). Further, the case where AHsur' is set to 10000 W/m2 is Equation (7). • &lt;求之法&gt; 熔 熔 in the mold: H. The equation (8) can be obtained by integrating the specific heat of the steel in the liquid phase at a temperature to obtain enthalpy, and expressing it as a function of temperature. H〇= (1x10 10χΤ〇4- 4χ10&quot;7χΤ〇3 + 0. 0005xT〇2- 0. 0098χΤ〇 + 098106495 25 200946265 4.5508)x4. 19x1000 (8) where T. : molten steel temperature in the mold (°c). Further, for the molten steel temperature T in the mold of the formula (8). In the conventional apparatus, the temperature of the molten steel in the mold can be actually measured by a thermocouple, and can be obtained as the following equation (9) of the complex regression equation according to the operating conditions at this time. T〇= 705. 156 + 0. 544086 Ttd- 2. 35053 Vc- 0.00303 W + 18. 12663 (0. 10181 · ln(FC)-〇. 3362) .........(9) where , Ttd: false tank (T/D: tundish) inside molten steel temperature (°c)

Vc: casting speed (m/min) W: casting (M/D: mold) width (m) FC. flow control (FC) flow current (A) As described above, ΗρΔΗ^'Η can be obtained. Therefore, it is possible to obtain ΑΗ according to the following formula (10) obtained by deforming the formula (4). ΔΗ= H〇—(Hi + AHsur) (10) ΔH corresponds to the amount of heat generated by heat removal during mold cooling from the furnace bath surface to the exit of the mold. In part, the thickness D of the solidified shell at the exit of the mold can be expressed by the following formula (2) using the total heat flux Q1. D = Q1/(AH · p ) (2) where P: the density of the solidified shell at the exit of the mold (kg/m3). Further, for p, it can be 5 The method of obtaining the solid iron density 'to the extent of the temperature' and making it a function of temperature is obtained by the formula (ιι) of the regression equation as 098106495 26 200946265. P = (-1. 686x10- W+ 2.7069xi〇-7 Τ^- 5. 2909xl〇-TiaVe+ 7. 9106)xl000 ......... (ii) Furthermore, IL·, ΔΗμ, Hg, The method of p is not limited to the above method and can be obtained by various methods. Furthermore, in the above study, the total heat flux Q2 acts as a molten steel stream impinging on the solidified shell, causing the molten steel stream, which is remelted by the solidified shell, to collide with sensible heat, from the total heat flux used to estimate the thickness of the solidified shell. Excluded. However, it can be considered that when the molten steel ejected from the impregnation nozzle is temporarily increased in the scale formation, that is, when the total heat flux Q2 exists, the solidified shell is re-dissolved by the molten steel flow. Delayed solidification. Therefore, it is also considered that the thickness of the solidified shell becomes thinner than the thickness of the solidified shell obtained by excluding only the total heat flux Q2. Therefore, the following is a description of a method for estimating the accuracy of the solidified shell thickness in consideration of the solidification delay caused by remelting. # The inventors considered that even if the remelting caused by the total heat flux Q2 occurs, the total heat flux Q2 is not used to re-melt the solidified shell, and a certain proportion of the total heat flux Q2 is used for remelting. If this is considered, and if the thickness of the solidified shell estimated from the total heat flux Q1 is taken as D, the thickness of the solidified shell which is considered to be remelted by the total heat flux 'Q2' will be set to D1, and Q2 X% is used for redissolution 'The following ratio relationship holds. Q1 : D=(Q1—X · Q2) : D1 If the above formula is sorted for D1, then =—X · 098106495 27 200946265 Q2/Q1) 〇 Therefore, as long as X can be obtained, it can be obtained. D1. Therefore, if the above-described proportional expression is collated with respect to X, X = (D_Dl) / D · Q1/Q2. The value of (D_D1)/D appearing in this formula is used as the retardation degree of solidification (RSCRetardation of Solidification). In the conventional literature, "the influence of molten steel flow and molten steel superheat on solidification delay" (( The Japanese Society for the Promotion of Science (Japan Society for the Promotion of Science), the 19th Committee of the Solidification Process Research Society, presents the data: p. 8~9), which reveals that the solidification delay can be prevented by the following formula (3). Got it. RS = 0χ(ν°.8.Δ0 ) (3) Cold: solidification delay constant (no unit) V: molten steel flow rate (m/s) △ 0 : molten steel superheat ( °C) RS : Solidification delay (no unit) As described above, the molten steel superheat degree Δ0 can be found as Δ &lt; 9 = T. —TS(T.: molten steel temperature (°C) in the mold, Ts: molten steel solidus temperature (.〇)), so only the molten steel flow rate V is required, and the RS can be obtained. Further, the molten steel flow rate V (m/s) can be obtained by the formula (13) using the total heat flux q2. V=(Q2/U · t · ΔΘ )) 125 .........(13) α : molten steel flow rate constant (no unit) 28 098106495 200946265 t: solidified shell arrives after a very small point in the distribution Time until the mold exit (8) '', % If (D - Dl) / D in the formula X = (D - D1) / D. Q1/Q2 is replaced by RS, then X = RS · Q1/Q2. If the value of X is substituted into the above D1 = D(1 ' - X · Q2 / Q1), then D1 = D(1 - RS), and the solidified shell thickness D1 considering the solidification delay can be obtained. As described above, the solidification delay degree RS shown in the above formula (3) can be obtained, because the solidification delay caused by the total heat flux Q2 can be obtained from D1 = D(1 - RS). The solidified shell thickness D1. In order to verify the validity of the above studies, D and D1 were obtained under several operating conditions, and the D and D1 were compared with the values obtained by other methods. As a comparison method, the following D' and D1 were calculated. D' = only the heat flux distribution of ql is used, and the shell thickness is calculated only by the heat rejection. That is, ql is used instead of ql - q2reg, and a value corresponding to the total heat flux amount Q (as Q') is calculated, and the value obtained by D, /(ΔΗ · ρ ) according to the above formula (2) is calculated. D1' = shell thickness in which the solidification delay is considered in D'. That is, the value obtained by Dl' = D' (1 - RS) according to rS.

Dreal = shell thickness estimated from the position of the internal crack of the cast piece 098106495 29 200946265 [Table 2]

Vc W Ttd Αθ FC D, Q' Dl' DQ RS Dl Dreal m/min m ec °CA mm kJ/m2 mm oun kJ/m2 % _ mm Condition 1 2.3 1.4 1560 19 359 15.3 31780 14.5 13.2 27420 5.6 12.5 12.0 Conditions 2 2.5 1.1 1551 16 334 13.9 28060 13.0 11.0 22200 6.8 10.3 10.7 Condition 3 2.0 1.7 1560 12 215 17.1 36280 16.6 15.5 32885 3.2 15.0 16.0 Condition 4 1.7 1.8 1553 15 133 19.0 40650 18.5 17.5 37324 2.7 17.0 16.2

Vc : casting speed W: casting width Τ π > : TD inner molten steel temperature ΑΘ : molten steel superheat ◎ FC : upper pole FC direct current RS : solidification delay From the above results, it can be seen that 'D and D1 are steadily close to the measured value The value, and especially D1, is a further improvement. Thus, the solidified shell thickness D at the exit of the mold can be obtained by using the total heat flux Q1, and the solidified shell thickness μ in consideration of the solidification delay can be obtained. Further, the thickness of the solidified shell can be determined by the right, and the relationship between the thickness of the solidified shell and the presence or absence of the casting leakage can be obtained in advance as an indicator of whether or not the casting leak occurs. For example, when the predicted thickness D reaches the threshold value, it can be judged to be under the condition that the leak occurs, or when the thickness is below the thickness D1 _ threshold, it can be in the condition of generating the casting leakage. Corresponding to _, equipment, operating conditions, - set the threshold according to the precedent in advance, or obtain the threshold by theoretical calculation. 0 098106495 30 200946265 Moreover, the indicator of whether or not the casting leak occurs is based on the exit of the mold. The thickness of the solidified shell is a more direct indicator than the above-mentioned change based only on the heat flux, so it can be said that the precision is high. Further, for the detection method based on Q1 or the Q1 and Q2 based on the above-described FIG. 10, although the process of actually calculating the thickness of the solidified shell is omitted, it is solidified according to Q1 and Q2. The effect of the shell thickness is used to predict the presence or absence of a casting leak, so that higher precision is also obtained. The present invention has been made based on the above findings, and specifically includes the following constitution. (1) A continuous casting casting leak detection method, comprising the steps of: measuring a heat flux of a molten steel in a continuous casting mold to a solidification interface during a period from a furnace bath surface to a mold exit; Step of the amount ql · According to the following formula (1), the step of stabilizing the solidification interface heat input q2reg from the flow of the molten steel in the mold under steady state is obtained; for the heat flux w and the stable condensation solid interface heat Enter the difference of ^reg (ql ~~ q2reg), and find the step of melting the surface from the scale: the heat flux distribution until the exit of the mold; and the step of determining the risk of rust leakage based on the read heat flux distribution. Q2reg=h.A0 ... (1) where h is the heat transfer coefficient between the molten steel and the solidified shell A0: the superheat of the molten steel. (2) The method for detecting a casting leak in the continuous casting according to the above (1), wherein the risk of casting leakage is determined based on the heat flux distribution obtained by the above (ql-q2reg) 098106495 31 200946265 The steps include: according to the heat flux distribution, the step of obtaining the total heat fluxes Q1 and Q2 by the following method is '1' (1) when the minimum value of the enthalpy is above, when the utilization amount is 77 The surface is extremely small. When the local minimum heat flux value at the exit of the mold is connected by a straight line, it will be equivalent to the area above the straight line. The total heat flux = Q2 will be set to Q1 with the following area. The area is from the total amount _ from the position of the bath surface to the exit of the scale die = the total _ of the package minus _ = two: when there is no minimum point indicating the minimum value in the flux distribution, From the position of the 敫 敫 敫 至 至 至 至 至 至 至 、 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , The step of zero. and ^ according to the above total heat flux Q1, or according to The step of judging the danger of casting a leak. ..., seat Again, the so-called total heat flux, according to the heat flux of the upper part of the feed rate.揭^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The indicator of heat reading, Q2 is used as a criterion for exceeding the stability of the (4) interface heat I. According to Q1 or according to the collection and acceptance, it is determined whether there is a risk of praying. Further, the present invention is the method for detecting a casting leak in the continuous casting according to the above (2), and in the step of determining whether or not there is a risk of casting leakage in the above-mentioned step 098106495 32 200946265, Q1 can also be used as an increase in value. To deal with the factor of reducing the risk of casting leakage, Q2 is treated as a factor that increases the risk of casting leakage by increasing the value, and the risk of casting leakage is determined according to Q1 or according to Q1 and Q2. (4) The method for detecting a casting leak in continuous casting according to (2) or (3) above, wherein the step of determining whether or not there is a risk of casting leakage based on the total heat flux Q1 is 'pre-set for Q1 The threshold value α b α 2 (α 1 &lt; α 2), 参() 田 Q1 &lt; α 1日寺' is judged to be a risk of casting leakage, (ii) when α 1 SQ1 $ α 2 'according to Q2 The value is determined to be a risk of casting leakage. Here, it is preferable that when Q2 reaches a threshold value (which may be a fixed value in the entire range of aal_Ql$a2) set in advance according to Q1, it is judged that there is a risk of a prayer leak. The casting leak detection method of continuous casting described in any one of the above, ';10_the above (ql - q2reg) obtained in the above heat flux distribution, there is a case indicating the threshold of the minimum detection setting At the time, relative to the threshold for Q1, ^(1)a2Ul&lt;a2) and _, or 4 1 for Q2, or (10) heart 1 and the risk of leakage. 11·. 2 and Q2 is judged as the method of continuous casting of the castings in this month. Continued casting _ ton □ 疋 疋 朝 朝 朝 朝 凝固 埶 埶 埶 : : : : 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 098 , the heat flux ql; according to the following formula (1) to obtain a stable shape 33 200946265 state of the molten steel flow in the mold caused by the steady solidification interface heat input q2reg; for the heat flux "with stable solidification interface heat input called The difference (ql - q2reg) 'determines the heat flux distribution of the molten steel from the furnace bath surface to the casting exit; and when there is a minimum point indicating the minimum value in the heat flux distribution, when using the straight line When the local heat flux value at the exit point of the mold is connected, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2', and the total heat flux corresponding to the following area is set to Q1. The area is the total heat flux from the total area enclosed by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold minus the area obtained by Q2, and is preset relative to Q1 Proximity limit, α2 (αΐ&lt; α2) and needle Q2 preset threshold stone 'when Ql&lt;al and Q2 2/3, or Ql&lt;al and Q2&lt;/3, or Q22 is absent, it is judged that there is a danger of pound leakage. (6) As above ( 5) The method for detecting the casting leakage of continuous casting, wherein the molten steel is extremely low carbon steel, α 1 is 15000 (kJ/m 2 ), α 2 is 2 l 〇〇〇 (kJ/m 2 ), and 々 is 4500 (kJ / M2) (7) The method for detecting a casting leak in continuous casting according to (2) or (3) above, wherein the step of determining whether or not there is a risk of casting leakage based on the total heat flux Q1 includes: using the total The heat flux Q1, the step of estimating the solidified shell thickness D at the exit of the mold according to the following formula (2); and the thickness D of the solidified shell estimated according to the above and the relationship between the pre-existing and the risk of casting leakage The threshold value is used to determine whether there is a risk of causing scale leakage. 098106495 34 200946265 D== Q1/(AH · p ) (2) where D: the thickness of the solidified shell at the exit of the mold Q1: total heat flux (j/y) AH: enthalpy drop per unit weight of the solidified shell at the exit of the mold (j/kg) P: solidified shell density at the exit of the mold (kg/m3) and 'the above ql Unit set to J/s.m2, in the above formula (1), the unit of q2reg is J/s · m2 ', the unit of h is J/s · m2 ·. 〇, the unit of A0 设为 is set to .C. (8 A casting leak detecting method of continuous casting according to (2) or (3) above, wherein when there is a minimum point indicating a minimum value in the heat flux distribution obtained for the above (ql - q2reg) The step of determining whether or not there is a risk of casting leakage based on the total heat fluxes Q1 and Q2 includes the step of estimating the solidified shell thickness D at the exit of the mold according to the following formula (2) using the above total heat flux Q1; Using the relationship of D1 ❷ = D (1 - RS), the solidification delay thickness RS determined by the following formula (3) is used to estimate the solidified shell thickness D1 in consideration of the solidification delay, which is caused by the total The remelting caused by the heat flux Q2 is generated; and based on the above-mentioned estimated solidified shell thickness D1 and the threshold value obtained in advance in relation to the risk of production and production of the casting leakage, the presence or absence of a pound leak is determined. - The dangerous step. D = Q1/(AH · p ) (2) where D is the thickness of the solidified shell at the exit of the mold (m) Q1 : total heat flux (J/m2) 098106495 35 200946265 △Η : the solidified shell at the exit of the mold Drop per unit weight (J/kg) p : solidified shell density (kW) at the exit of the mold RS = y (9x(V0'8*A6&gt; ) ... (3) where RS : Solidification delay (no unit) y?: Solidification delay constant (no unit) V: Melt flow rate (m/s) Δ0 : Glazing steel superheat (°C)

Here, V = (Q2 / (a · t · ΑΘ )) 125 Q2 : total heat flux (J / m2) α : molten steel flow rate constant (no unit) t: solidified shell through the heat flux distribution is very small Time required to reach the exit of the mold after the point (S)

Further, 'the unit of ql is set to j/s · m2, and in the above formula (1), the unit of q2reg is J/s · m2 ', and the unit of h is set to j/s · m2 ·乞, The unit of △ 0 is set. C. Furthermore, it is preferable that the above method estimates the thickness of the solidified shell at the exit of the mold when there is no minimum point indicating the minimum value in the heat flux distribution obtained for the above (ql - q2reg), Above = (7) $ q2reg), the above-mentioned heat flux distribution obtained by the above is called small

In the case of a point, the pole 'J thickness' at the exit of the mold is estimated by the method of the above (8), and it is dangerous according to the estimated value and the upper limit value. .,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, A plurality of thermocouples are provided in accordance with the above-mentioned - for the output of the thermocouple, the local heat flux obtained by the following formula (4). The above-mentioned oblique thermocouple is buried in the mold in the thickness direction of the pound mold. Two points with different depths. Ql= λ(Τ1—T2)/d (4) where λ : thermal conductivity of the mold 10 ΤΙ, Τ 2 : detection temperature of the thermocouple d: embedding interval of the thermocouple (10) A casting and leak detecting method for continuous casting according to (7) or (8) above, wherein the heat flux q1 is a plurality of pairs of thermocouples in the thickness direction of the mold, based on the output of the pair of thermocouples The heat flux of the above formula (4) is obtained by embedding the pair of thermocouples into the mold at two points of different depths of the thick sound of the mold (4) q1 ~ λ ( ΤΙ — Τ2)/d where λ : thermal conductivity of the mold (J/s · m · °C) ΤΙ, T2 : temperature of the thermocouple (°C) d : buried interval of the thermocouple (m) ( 11) A continuous casting casting leakage detecting device comprising: a thermocouple group formed by providing a plurality of thermocouples in a casting direction of the casting mold, the pair of thermocouples being embedded in a depth in a thickness direction of the casting mold Two different points; 098106495 37 200946265 Local heat flux calculation method, input the temperature information from the thermocouple group and find the location of each thermocouple setting part Partial heat flux ql; stable solidification interface heat input memory means, memory according to the following formula (1) obtained in the steady state of the molten steel flow in the mold caused by the steady solidification interface heat input q2reg data; distribution operation means, For the difference between the heat flux ql and the stable solidification interface heat input q2reg (ql - q2reg), the heat flux distribution of the molten steel from the furnace bath surface to the mold exit is obtained; and the casting leakage determination means is obtained according to the obtained The heat flux distribution determines the risk of casting leakage. Q2reg= h · Δ θ (1) where h: the heat transfer coefficient between the molten steel and the solidified shell ΑΘ : the superheat of the molten steel. (12) The casting and leak detecting device for continuous casting according to (11) above, wherein the casting leakage determining means is as follows: based on the heat flux distribution, the total heat fluxes Q1 and Q2 are obtained by the following method: (i) in the case where there is a minimum point indicating the minimum value in the heat flux distribution, when the minimum heat flux value at the exit of the mold is connected by a straight line, the area above the straight line is The equivalent total heat flux is set to Q2, and the total heat flux corresponding to the area is set to Q1, which is surrounded by the entire curve from the heat flux distribution from the bath surface position to the mold exit. The total area is equivalent to the total heat flux minus the area obtained by Q2, and (ii) when there is no minimum point indicating the minimum value in the heat flux distribution, the position from the bath surface to the mold The heat flux between the outlets is 098106495 38 200946265 The total heat flux of the total area of the gj package is set to the total heat flux Q1, and Q2 is set to zero, according to the above total heat flux Q1, Or determine the risk of casting leakage based on Q1 and Q2. (13) The casting and leak detecting device for continuous casting according to the above (12), wherein the above-mentioned prayer leakage determining means is such that the total heat flux Q1 is used as an index of heat generation caused by solidification, and if necessary Use q2 as an indicator of the heat input exceeding the stable solidification enthalpy interface, and determine whether there is a risk of casting leakage according to Q1 or according to Q1 and Q2. Further, the casting and leak detecting device of the continuous casting according to the above (12), wherein the casting leakage determining means is as follows: Q1 is treated as a factor that reduces the risk of casting leakage by increasing the numerical value, and Q2 is treated as a factor that increases the risk of scale leakage by increasing the value and determines whether there is a risk of pound leakage based on Q1 or according to Q1 and Q2. (14) The casting and leak detecting device for continuous casting according to (12) or (13) above, wherein the above-mentioned casting leakage determining means is as follows: a predetermined threshold value with respect to the total heat flux Q1 described above α 1 , α 2 ( α 1 &lt; α 2), (丨) When Q1 &lt; α .1, it is judged that there is a risk of casting leakage, and (8) when it is in the field, it is judged to have a casting leak according to the value of • Q2 The danger. Here, it is preferable that when Q2 reaches a threshold value (which may be a predetermined value in the entire range of the heartbeat) which is set in advance according to Q1, it is preferable to have a risk of praying. The casting leakage detecting device of the continuous casting according to the above (12) or (13), wherein the casting leakage determining means is as follows: the heat obtained by the above (ql - q2reg) When there is a case where the minimum value indicating the minimum value exists in the flux distribution, the threshold value α ΐ, 1 &lt; α 2) preset for Q1 and the threshold value set in advance for Q2, when (i) Ql &lt; When α 1 and Q2 2/5, or (ii) Ql &lt; α 1 and Q2 &lt; 召, or (iii) a 1SQ1S α 2 and Q2 2 /3, it is judged that there is a risk of casting leakage. That is, the continuous casting casting leak detecting device of the present invention is characterized by comprising: a thermocouple group formed by providing a plurality of thermocouples in a casting direction, and the pair of thermocouples are buried in the thickness direction of the mold. Into the two points with different depths; local heat flux calculation means, input the temperature information from the thermocouple group to obtain the local heat flux ql of each thermocouple setting part; stable solidification interface heat input memory means, memory basis The data of the stable solidification interface heat input q2reg caused by the flow of the molten steel in the mold under the steady state (1) obtained by the following formula (1); the distribution calculation means, the difference between the heat flux ql and the stable solidification interface heat input q2reg (ql - q2reg), the heat flux distribution of the molten steel from the furnace bath surface to the exit of the mold is obtained; and the casting leakage determining means has a minimum value in the heat flux distribution obtained by the distributed computing means In the case of a very small point, when a local heat flux value at the exit point of the mold is connected by a straight line, the total heat flux corresponding to the area of the upper portion of the straight line is used. For Q2, the total heat flux equivalent to the following area is set to Q1, which is the total area enclosed by the line 098106495 40 200946265 from the heat flux distribution from the bath surface position to the mold exit. The equivalent total heat flux minus the area obtained by Q2, and for the threshold values α 1 , α 2 ( α 1 &lt; α 2 ) preset for Q1 and the threshold stone preset for Q2, when Ql &lt; α 1 and Q2 2 yS, or Ql &lt; α 1 and Q2 &lt; /3, or a 1SQ1S α 2 and Q22 /3 are judged to be a risk of casting leakage. (16) The casting and leak detecting device for continuous casting according to the above (15), wherein, in the case where the molten steel is extremely low carbon steel, α 1 is set to 15000 (kJ/m 2 ), and α ❹ 2 is set to 21000 (kJ/m2), set /3 to 4500 (kJ/m2). (17) The casting and leak detecting device of the continuous casting of the above (12) or (13) wherein the above casting leakage determining means includes: a solidified shell thickness calculating means, using the total heat flux Q1' according to the following formula (2) And calculating the thickness D of the solidified shell at the exit of the mold; and the main body of the casting leakage determining means, inputting the calculated value of the solidified shell thickness calculating means, based on the calculated value D and the relationship with the risk of casting leakage in advance The limit value is obtained to determine whether there is a risk of casting leakage. 〇D = Q1/(AH · p ) (2) where ' D : solidified shell thickness at the exit of the mold (m) Q1 : total heat flux (J/m2) . ΔΗ :焓 每 (j/kg) per unit weight of the solidified shell at the exit of the mold. P : solidified shell density at the exit of the mold (kg/m3) and 'the unit of ql above is set to J/s · m2, in the above formula In (1), the unit of q2reg is set to J/s · m2 'The unit of h is set to j/s · m2 · °C, and the unit of Δ6» is set. C. 098106495 41 200946265 (18^-hi4(12)^(13)^, the above-mentioned casting leakage determination means U· device heat flux Q1, according to the following formula (2, zirconia pine, Danyu only use the total calculation, into岐 (4) According to the material correction D, ni, ni_nn_nCN The solidification delay RS of the clothing, by the relationship of Μ = Ι) (-RS), the coagulation delay is caused by the total heat flux Q2::t solves the generator; and the method of casting and leaking judgment: the calculation value of the re-shock calculation method of the two, according to "· m loses the money, the thickness of the solid shell (4), the calculated value D1, and the county's risk There is a risk of loss (4) leakage D - Q1/(ΔΗ · p ) (2) where D: the thickness of the solidified shell at the exit of the mold (m) Q1 : total Heat flux (J/m2) △Η ··The drop per unit weight of the solidified shell at the exit of the mold (J/kg). The solidified shell density at the exit of the mold (kg/m3) RS= /3x(V° 8·Δ6» ) (3) where 'RS : solidification delay (no unit) 10,000: solidification delay constant (no unit) v : molten steel flow rate (m/s) △Θ : Fused steel superheat (°c) where V = (Q2/( α · t · A 0 )) 125 Q2 : total heat flux (J/m2) α : molten steel flow rate constant (no unit) 098106495 42 200946265 t: time required for the solidified shell (4) to reach the scale exit after the minimum point in the heat flux distribution (4), and the unit of ql above is set to J/ S.m2, in the above formula (1), the unit of _ • is set to J/S · m2, the unit of h is set to J/s · β t, and the unit of " is set to .C. Further, the solidified shell described above Preferably, the calculation means is: when there is no minimum point of the minimum value in the heat-passing knife cloth of (8)--), the thickness of the solidified shell at the exit of the mold is calculated by the above method ((7), When there is a minimum point indicating a minimum value in the heat flux distribution, the thickness of the solidified shell at the exit of the die is calculated by the above method ((8). (19) A continuous casting casting leakage preventing device is used The casting and leak detecting device according to any one of the above (11), wherein the control means inputs a signal of the casting leakage determining means, and the casting leakage determining means determines that In the case of the danger of casting leakage, the control operation is to reduce the casting speed. Or, in addition to the control, control for lowering the flow rate of the molten steel in the mold. (20) A continuous casting casting leakage preventing device using any one of the above (11) to (18). The casting leakage detecting device is characterized in that: the package includes a control means, and the control means inputs the nickname of the casting leakage determining means, and when the casting leakage determining means determines that there is a risk of casting leakage, the casting speed is slowed down The way to control. (21) A continuous casting casting leakage preventing device, which is a casting leak detecting device of the above-mentioned 098106495 43 200946265 (15) or (16); characterized in that it comprises a control means, the control means When the signal of the scale leakage determination means is input, and the risk of money leakage is determined by the casting method, (1) when the risk determination is based on the risk determination of Q1 &lt; α丨A Q2^, (a) to reduce the casting Speed and / or increase mode cooling mode to control operating conditions ' or (6) in addition to the control, to control the flow rate of the red steel in the mold; (Π) when based on Q1 &lt; α 1 and the risk determination, Reduce the casting speed and / or enhance the cooling mode of the mold to control the operating conditions; (5) When based on the Q2 "danger determination, carry out (A) reduce the flow rate of the molten steel in the mold ' or (8) reduce the casting speed and / or enhance Control of mold cooling. (10) - Connection of steel type _ spurting, money making time (4) Leak detection method; characterized by controlling the operating conditions in the following manner, that is, (1) making Q1 &gt; α 2, or (jj) Shop]&lt;m judged to have The risk is 2 and Q2 is a continuous transfer method of the (10)-type steel, which is the method for detecting the casting and leaking of the above (5) or (6); characterized in that it is Q1 &gt; W and _ no Or the operating condition is controlled by the method of Qlg α 1 and q2 &lt; 0. (24) The continuous casting method of steel according to (23) above, wherein, in operation, (1) when Ql &lt; α 1 and then '(4) to lower the speed of the pound And / or enhance the cooling of the mold to the operating conditions, or in addition to the control material, (8) to control the operating conditions in a manner to reduce the flow of the flow of the mold, when Q1 &lt; 098106495 200946265 α ΐ and Q2 &10000; The operating speed is controlled by the speed and/or the way of strengthening the scale mold. (iii) When tal_^2 is received, the operating conditions are controlled as follows: (A) the molten steel flow in the scale mold is lowered, or (8) is lowered. (25) A method of continuous pound making of steel according to any one of the above (22) to (24), wherein 'the heat flux dl is set in a plurality of casting directions of the mold A pair of thermocouples' according to the above-mentioned Lai 读 reading (4) is obtained by the following formula (4). Flux, above - for the thermocouple to be buried between the two points in the die in the thickness direction of the mold, the difference between the two points. ql = λ (Tl-T2) / d ......... (4) where 'λ: thermal conductivity T1 of the mold: detection temperature of the thermocouple d: embedding interval of the thermocouple (26) - continuous casting method of the steel, which uses the casting leakage test of the above (7) The method of controlling the operating conditions is such that the estimated solidified shell thickness D is greater than a threshold value determined in advance in relation to the risk of occurrence of leakage. ♦ (27) A continuous casting method for steel, which uses the casting-drain detecting method as described in the above (8); so that the estimated solidified shell thickness D1 is smaller than the relationship with the risk of casting leakage. The method of obtaining the threshold value and controlling the operating conditions. Furthermore, it is preferred that when there is no minimum point 098106495 45 200946265 in the heat flux distribution of (q1 - d2reg), continuous casting is performed by the method of (26) above, and when there is a minimum point, the above (27) is utilized. The method performs continuous casting. (28) A method for estimating the thickness of a solidified shell for continuous casting, characterized in that it comprises: determining a heat flux of heat input to a solidification interface during a period from a furnace bath surface to a mold exit in a mold in continuous casting Step of ql; determining the steady solidification interface heat input q2reg caused by the flow of the molten steel in the mold under steady state according to the following formula (1); and the heat flux ql (J/s · m2) and the stability The difference between the heat-reducing interface heat input Q2reg (Ql - Q2reg) 'steps to obtain the heat flux distribution of the molten steel from the furnace bath surface to the exit of the mold; and (i) the minimum value of the heat flux distribution In the case of a very small point, when the minimum heat flux value at the exit of the mold is connected by a straight line, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2, which is equivalent to the following area. The total heat flux is set to Q1, which is the total heat flux from the total area enclosed by the entire curve of the heat flux distribution from the bath surface location to the exit of the mold minus the area obtained by Q2. , (ii) above the heat flux When there is no minimum point indicating the minimum value in the distribution, the total heat flux corresponding to the total area surrounded by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold is set as the total heat. The flux Q1, using the total heat flux Q1, estimates the solidified shell thickness D at the exit of the mold according to the following formula (2). Q2reg = h · ΑΘ .........(1) where q2reg : stable solidification interface heat input (J/s · m2) 098106495 46 200946265 h : heat transfer coefficient between molten steel and solidified shell ( J/s · m2 · °C ) A0 : superheat of molten steel (°C) D = Ql/(AH.p) ... (2) where D: solidification at the exit of the mold Shell thickness (m) Q1: Total heat flux (J/m2) AH: enthalpy drop per unit weight of the solidified shell at the exit of the mold (J/kg) p : solidified shell density (kg/m3) at the exit of the mold. Φ (29)—a method for estimating the thickness of a solidified shell of continuous casting, which is based on the case where there is a minimum point indicating a minimum value in the heat flux distribution, and the solidification delay system is estimated by considering the solidification shell thickness D1 considering the solidification delay. Produced by remelting caused by the total heat flux Q2; characterized in that D1 = D(1 - RS) when the solidified shell thickness obtained by the above (28) is taken as D. Where RS = /3χ(ν°.8·Δ0 ) (3) RS : solidification delay (no unit) φ yS : solidification delay constant (no unit) V : molten steel flow rate (m/s) Α6» : Fused steel superheat (°C) ^ Here, V=(Q2/(a · t · Δ0 )) 125 Q2 : Total heat flux (J/m2) α : Melt flow rate Constant (no unit) t: Time required for the solidified shell to reach the exit of the mold via the minimum point in the heat flux distribution (S) 098106495 47 200946265 Furthermore, it is better to be the heat-pass distribution of (ql-q2reg) When there is no minimum point, the solid shell thickness (D) is estimated by the method of (28) above, and when there is a minimum point, the solid shell thickness (D1) is estimated by the method of the above (29), thereby respectively estimating the solidified shell. thickness. (30) The method for estimating the thickness of a solidified shell of continuous casting according to (28) or (29) above, wherein 'the heat flux ql is a plurality of pairs of thermocouples in the casting direction of the mold, according to the pair of thermocouples The local heat flux obtained by the following formula (4) is outputted, and the pair of thermocouples are buried between the two points in the mold in which the depth of embedding in the thickness direction of the pound mold is different. Ql= λ (Tl-T2)/d (4) where 'Ql: heat flux (J/s · m2) into: thermal conductivity of the mold (J/sm· °C ΤΙ, T2: Thermocouple detection temperature CC) d: Thermocouple buried interval (m) (3υ - a continuous casting solid shell thickness estimation device, characterized by a square thermocouple group, in the casting direction of the mold Set a plurality of formations, ... 〆 * (four) into, the - the thermocouple is buried in two different depths; the temperature of the local galvanic group (four) and the local hot-through heat into the memory means According to the following formula (1), the flow of molten steel in the mold is called the stable solidification interface input 'm cloth operation means, needle _ 098106495

48 200946265 The difference between the heat input q2reg of the solidification interface (ql-q2reg), the heat flux distribution of the molten steel from the furnace surface to the exit of the mold; and the calculation method of the solidified shell thickness, (i) by the distribution operation If there is no minimum point indicating the minimum value in the heat flux distribution obtained by the means, it will be equivalent to the total area surrounded by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold. The total heat flux is set to the total heat flux Q1, and (ϋ) when there is a minimum point indicating a minimum value in the heat flux distribution obtained by the distribution operation means, when the minimum point is connected by a straight line When the local heat flux value at the exit of the mold is set, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2, and the total heat flux corresponding to the following area is set to Q1, which is self-contained. The total heat flux corresponding to the total area enclosed by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold minus the area obtained by Q2, using the total heat flux Q1, according to the following formula (2) The solidified shell thickness at the exit of the mold D is operated. 10 q2reg = h · Δ0 (1) where q2reg : stable solidification interface heat input (J/s · m2) h : heat transfer coefficient between molten steel and solidified shell (J/ s · m2 · °C) • Δθ: superheat of molten steel (°C) - D = Ql/(AH.p) ... (2) where D: solidification at the exit of the mold Shell thickness (m) Q1 : Total heat flux (J/m2) △Η : 焓 drop per unit weight of solidified shell at the exit of the mold (J/kg) 098106495 49 200946265 p : solidified shell density at the exit of the mold (kg /m3). (32) The solidified shell thickness estimating device according to (31) above, wherein the solidified shell thickness calculating means takes the solidified shell thickness considering the solidification delay as D1, and the solidification delay is caused by remelting caused by the total heat flux Q2. Producer, let D1 = D(1-RS). Where RS = θχ(ν°·8·Δ(9 ) ... (3) /3 : solidification delay constant (no unit) V : molten steel flow rate (m/s) ΔΘ : molten steel Superheat (°C) RS : Solidification delay (no unit) Here, V=(Q2/(a · t · Δ0 )) 125 Q2 : Total heat flux (J/m2) α : Steelmaking flow rate constant ( t unit) t: time required for the solidified shell to reach the exit of the mold through the minimum point in the heat flux distribution (S) Further, it is preferable that the heat flux distribution of the solidified shell thickness estimating device is (ql - q2reg) When there is no minimum point, the method (31) above is used to estimate the solidified shell thickness (D), and when there is a minimum point, the solidified shell thickness (D1) is estimated by the method of (32) above, thereby presuming solidification, respectively. [Embodiment] FIG. 1, FIG. 12 and FIG. 13 are views showing a continuous leak-making apparatus for a casting leak detection and prevention apparatus and a solidified shell thickness estimating apparatus according to an embodiment of the present invention, 098106495 50 200946265. The same parts as those in Fig. 2 are denoted by the same symbols. Continuous town. Equipment includes: • Mold 1, • Dip nozzle 3, connected to the bottom of silver tank 40 Placed in the scale die 1 'spray the molten steel 5 from the feed tank 40; • The guide roller 21' guides the tab 19 from the mold 1; • Pinch rol 1 23 for extracting the town a sheet 19; a motor 25 for rotationally driving the pinch roller 23; and a pinch roller control device 27 for controlling the motor 25. In the continuous casting apparatus of such a configuration, the following composition is provided The casting leakage preventing device (including the pound leak detecting device and the solidified shell thickness estimating device). The casting leakage preventing device includes: • a thermocouple group, wherein a plurality of thermocouples 17 are placed in the width direction of the mold and the casting direction. The pair of thermocouples 17 are embedded in two points of different depths of the mold copper plate 11 t shaped into the mold 1; • a local heat flux calculation means 29, the thermocouple group in the thickness direction of the dragon The temperature information is calculated for each thermocouple from the Λ flux; the local heat·stable solidification interface heat input memory means 31, U is based on the next n to obtain the steady state of the molten steel flow in the mold Enter the data of q2reg; stable solidification The surface/heat flux distribution calculation means 32, for the difference between the heat _ ^ ql and the stable condensation 098106495 200946265 solid interface heat input q2reg (ql-q2reg), obtain the heat flux from the furnace surface to the mold exit The amount distribution; the casting leakage determining means 33 determines whether or not there is a risk of casting leakage based on the obtained heat flux distribution; • the control means 35 inputs the signal of the casting leakage determining means 33, and the sleep leakage determining means 33 determines that When there is a risk of casting leakage, (i) control by slowing down the casting speed (Fig. 13), U) control by slowing down the casting speed and/or to make the scale mold (the flow rate of the molten steel inside is lowered) Controlling the mode (Fig. 12), or (iii) controlling the operating conditions by reducing the casting speed and/or enhancing the cooling of the mold, or in addition to the control, controlling the flow rate of the molten steel in the mold (Fig. 1); and • The alarm device 37 issues an alarm when the casting leakage determining means 33 determines that there is a risk of leakage. Q2reg = h · Δ Θ ... (1) where h: the heat transfer coefficient between the molten steel and the solidified shell ΔΘ: the superheat of the molten steel is in the casting leakage prevention device of Fig. 1, casting The leak determining means 33 further includes: • a solidified shell thickness calculating means 34 for calculating total heat fluxes Q1 and Q2 based on the heat flux distribution obtained by the distributed computing means, and using the total heat flux Q1, Or using Q1 and Q2, calculating the thickness (solidified shell thickness) of the solidified shell 9 at the exit of the mold; and 098106495 52 200946265 • casting leakage determining means body 33A, inputting the calculated value of the solidified shell thickness calculating means 34 and according to The calculated value and the threshold value obtained by the relationship with the risk of casting leakage are used to determine whether or not there is a risk of casting leakage. Hereinafter, each configuration will be described in more detail. &lt;Thermocouple&gt; The thermocouple 17 is buried in the mold copper plate u as shown in Figs. 3 and 4 . That is, at the bottom of the cooling water passage 13 formed on the outer side surface of the tungsten mold copper plate 11.

A hole 15 (see FIG. 3) is formed in which a thermocouple 17 is buried, and a pair of thermocouples 17 are provided in nine places (total of 18) in the casting direction of the mold, and the pair of thermocouples 17 are buried in the depth direction. Two parts of a fixed distance. Furthermore, in the present embodiment, the thermocouple 17 is embedded in the short side and the long side of the mold (on the longer side in the mold of the horizontal cross-section growth body), and each side of the scale mold is measured, according to The value of each side (four) is used to determine whether there is a slip. &lt;Local heat flux calculation means&gt; The two-part heat flux calculation means 29 inputs (4) the thermocouple 而 and operates on the local flux Qlit row. The local heat flux calculation means 29 is executed by the central unit _ 'Central Pr〇cessing Unit), and in this program, the temperature of the two thermocouples 17 is set to ΤΙ, T2 as described above. 'Set the embedding interval to d α and set the thermal conductivity of the mold 1 to λ, and write the local heat flux below the formula (4). Ql= λ (Tl-T2)/d .........(4) 098106495 200946265 &lt;Stabilization of solidification interface heat input memory means&gt; Stable solidification interface heat input 5 Memories means 31 memory as follows, According to the following equation (1), the steady-state solidification interface heat input q2reg of the steady state is obtained. Q2reg= h · Δ θ (1) where h=l. 22xl05xV°_8 V : molten steel flow rate (m/s) ΑΘ =T〇-Ts

To : The temperature of the molten steel in the mold (°C) Ts : The solidus temperature of the molten steel (°C) In addition, the method of obtaining the stability _ the interface of the hot wheel person I is operated at a predetermined casting speed. According to the dip angle of the scale of the scale, the flow rate is obtained, and the simple axis (1) is used to obtain the stable solidification interface heat input q2 "., '', and soil, according to - &lt;heat flux distribution calculation means&gt; The heat flux distribution calculation means 32 from the stable solidification interface of each of the operation hands TM·...the heat wheel is entered into two: the heat flux difference f is obtained from the paste (10) the material curry heat flux distribution operation means 32 and the CPU M ^ π I The familiar flux calculation method is executed by the CPU. The current process is described in the program. The logic of the above heat flux distribution is calculated in the program. &lt;solidified shell thickness calculation means&gt; The solidified shell thickness calculating means 34 provided in the casting leakage preventing means calculates the solidified shell thickness D at the exit of the mold based on the heat flux distribution obtained by the heat flux distribution calculating means 32. The specific arithmetic method As described below, the heat flux obtained by the heat flux distribution operation means 32 When there is no φ in the distribution, in the case of indicating the minimum point of the minimum value, the total heat flux corresponding to the total area surrounded by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold is set to Q1, using the total heat flux Q1, the solidified shell thickness D at the exit of the mold is calculated according to the following formula (2). Further, there is a representation in the heat flux distribution obtained by the heat flux distribution calculating means 32. In the case of a minimum of the minimum value, when the local minimum heat flux value at the exit of the mold is connected by a straight line, the total heat flux corresponding to the area above the straight line of the straight line is set to Q2, The total heat flux corresponding to the area is set to Q1, which is the total heat flux minus the total area enclosed by the entire curve of the heat flux distribution from the bath surface position to the mold exit. To the area obtained by Q 2 , the total heat flux Q1 is used and the solidified shell thickness D at the exit of the mold is calculated according to the following formula (2) (refer to Fig. 9). D-Q1/(AH· p) .. (2) where D: solidified shell thickness at the exit of the mold (m) AH: mold exit The enthalpy drop per unit weight of the solidified shell at the place (J/kg) 098106495 55 200946265 p : solidified shell density at the exit of the mold (kg/m3) Further, as a calculation method for further improving the accuracy, the solidified shell thickness calculation means 34 It is also possible to calculate the solidified shell thickness D1 in consideration of the solidification delay by the solidification delay degree RS obtained by the following formula (3) by the formula D1==D(1 - RS), which is caused by the total heat The remelting caused by the flux Q2 is generated. When there is no minimum point in the heat flux distribution, whether D is used instead of D1 or Q2 = 0, the algorithm of D1 is obtained. The results obtained are all the same, so either one can be selected. RS=βχ(Υ〇κΑΘ) .........(3) /3 : Solidification delay constant (no unit) V : Melt flow rate (m/s) ΑΘ : Fused steel superheat (°C) RS: solidification delay (no unit) Here, V = (Q2 / (a · t · A (9 )) 125 Q2 : total heat flux (J / m2) α : steelmaking flow rate constant (no unit) t : time required for the solidified shell to reach the exit of the mold through the minimum point in the heat flux distribution (S) &lt; casting leakage determining means&gt; In the casting leakage preventing apparatus of Fig. 1, the casting leakage determining means 33 has the above solidification The shell thickness calculating means 34 and the casting leakage determining means main body 33A. In the casting leakage preventing means of Figs. 12 and 13, the casting leakage determining means 33 does not operate via the solidified shell thickness 098106495 56 200946265 degrees, but is based on the heat flux distribution. The heat flux distribution calculated by the calculation means 32 directly determines whether or not there is a risk of casting leakage. Hereinafter, the case will be described in each case. In the case of the casting leakage preventing device of Fig. 1, the casting leakage determining means body 33A is input to the solidified shell. The calculated value of the thickness calculation means 34 (solidified shell thickness d or D1), based on the calculated value and the risk of generating a pound leak in advance The relationship between the thresholds is determined to determine whether there is a risk of casting leakage. 临 The threshold value is for each of Ql, Q2 and the thickness of the solidified shell relative to the solid shell, and whether there is a casting leak under the thickness of the solidified shell. It is obtained by obtaining the data in the simulation experiment or the actual operation in advance. For example, the target solidified shell thickness at the exit of the mold is set to a value (or a numerical range) in the range of 20 to 30 mm, and the solidified shell thickness is 5 The value in the range of ～7 mm is used as the threshold value for determining the risk of casting leakage. Φ In the case of the casting leakage preventing device of Fig. 12 or Fig. 13, the casting leakage determining means 33 is based on the heat flux. The heat flux distribution calculated by the distribution calculation means 32 obtains, for example, the relationship between Q i and q 2 shown in FIG. 9 , and determines whether or not a casting leak occurs based on the relationship and the threshold value set in advance. For example, the relationship between Q1 and q2 shown in Fig. 9 is obtained based on the relationship with the pre-set a1U1 &lt;a2) for milk and the threshold α1 threshold A set in advance for Q2, as shown in Fig. 10. Danger of leakage. The basis shown indicates whether or not there is a casting 098106495 57 200946265 Q2 <cold or (ΰ1) α1 (four) and (four) million, it is judged that there is a danger of casting leakage. When the casting leakage determining means 33 determines that the risk of the leak is (10), the control hand & outputs the key point of the determination. In this case, it is preferable to output the risk of the prayer leak based on Q1 &lt; α 1 to 2, Or based on Q1 &lt; α 1 and Q2 &lt; cold, or based on Q2g stone. Further, the limits α 1 , α 2, / 3 depend on the type of molten steel, for example, when the molten steel is extremely low carbon steel. , α 1 = 15 〇〇〇 (kj/m 2 ), “ 2 = 21000 (kJ/m 2 ), stone = 4500 (kJ/m 2 ). Further, the term "very low carbon steel" means a carbon content of 0.001 mass% or less. Other benchmarks based on the Q1 benchmark or based on the relationship between 卯 and Q2 can also be used. For example, in the above example, it is also possible to determine whether there is a risk of a pound leak when MalSQ1$a2 or when it is received in more detail than the threshold of Q1 according to Q1. As another method, for example, when the ratio of the ratio Q2/Q1 is equal to or greater than the threshold value set in advance, it is determined that there is a risk of casting leakage. The threshold value depends on the flipping of the sense, for example, when the object is extremely low carbon steel, the 0. 25 〇 casting leak determining means 33 or the casting leak determining means 33A is also realized by executing the established program by (3). The logic of the above determination is written in the program. &lt;Control means&gt; When the casting leakage determining means 33 determines that there is a risk of casting leakage, the root device 098106495 58 200946265 controls various devices to prevent scale leakage based on the determination result. For example, in the case of the casting leakage preventing device of Fig. 12, specifically, regarding the above-mentioned dd and 々, the control means 35 is rotated from the tungsten leak determining means 33 by Q1 &lt;al; The signal of the danger of casting leakage caused by the pinch is sent to the signal indicating the speed of the slowing motor 25. In addition, in addition, the output of the electromagnetic brake device 41 can also be applied. a signal of a DC magnetic field in which the flow rate of the molten steel in the mold 1 is decreased. Further, if the control handcuffs section 35 inputs a signal indicating a risk of leakage due to Q1 &lt; α i and Q2 &lt; cold, The pinch roller control device 27 outputs a signal indicating that the rotation speed of the motor 25 is slowed down. Further, the control means commits a signal to the electromagnetic brake device if a signal indicating the risk of a pound leak due to the stone is input from the casting leakage determining means 33. 41 outputs a signal of a DC magnetic field to which the flow rate of the molten steel in the mold 1 is lowered. Further, in the case of the casting leakage preventing device of Fig. 1, specifically, the control hand segment 35 is input from the scale leakage determining means 34. If there is a danger of the risk of scale leakage, the pinch roller control device 27 outputs a signal indicating that the rotation speed of the motor 25 is slowed down. In addition, the output of the electromagnetic brake device 41 may be applied as in the mold 1. Melt flow rate decreases In the case of the casting leakage preventing device of Fig. 13, when the control means 35 inputs a signal indicating the risk of casting leakage from the casting leakage determining means 33, it is controlled only by slowing down the casting speed. That is, the pinch roller control device 27 outputs a signal indicating that the rotation speed of the motor 25 is slowed down. 098106495 59 200946265 Other than that, although not shown in the drawings, the following control can be performed. , _ cast Huan cooling water (four) casting money but control means to send the bell, strengthen the mold cooling and add solidified shell thickness. This control can effectively respond to the lack of heat caused by the lack of Q1 casting. &quot; Control 35 The logic for outputting the command signal is also written in the program by the CPU. The &lt;alarm device&gt; alarm device 37 inputs an _alarm from the prayer leak determining means 33. The type of the alarm is not limited. For example, (5) to deal with such a combination, etc. n's (4) lighting, for the embodiment of the present embodiment, the self-impregnated nozzle 3 in the mouth of the molten steel 5 Exercise of 19 In the process, the local heat is supplied from the capacitor 71 and the local heat flux means 29 is applied to the local heat to the result of the calculation, and is input to the distribution operation means 32. 埶, ,, &lt; The amount of calculation means deducting the key into the 1st hand Ql, and Ji Yi in the stable solidification interface heat input memory hand 11:, the solid-solid interface heat input q2w, the ql- must be "material, / the stable coagulation operation ~ fruit The heat flux distribution is calculated. Then, regarding the heat flux distribution obtained by the calculation 098106495 200946265, Q1 shown in Fig. 9, for example, is obtained, and the arithmetic values Q1 and Q2 are rounded up to the casting leakage determination means.

In the case of the leak prevention device of Affi 12 _ 13, the casting leakage determining means 33 judges whether or not there is a risk of a pound leak based on a predetermined rule for the Q1 to be wheeled or the Q2 to be input. For example, the relationship between the values of Q1 and Q2 in Fig. 12 and the aforementioned threshold values αΐ, α2, and /5 are used to determine whether or not there is a risk of slipping. In the case of the casting leakage preventing device of Fig. 1, the solidified shell thickness calculating means 34 first obtains the total heat flux Q1 by the above method based on the heat flux distribution obtained by the heat flux distribution calculating means 32. Or find Q2 in turn. Then, the solidification thickness calculation means 34 (4) calculates the solidified shell thickness d or 处 at the exit of the mold according to the total heat flux Q1 or according to Q2 by the above method. Further, the main body of the casting leakage determining means inputs the solidified shell thickness D or D calculated by the solidified shell thickness calculating means 34, and determines whether or not there is a risk of praying by the relationship between the threshold value and a predetermined threshold value. When the result of the judgment is that there is no danger of casting leakage, continue the operation as it is. • On the other hand, when the result of the determination is that it is determined that there is a risk of casting leakage, the casting leakage determining means 33 outputs a signal indicating that there is a risk of casting to the control means 35. At the same time, when the command signal for issuing an alarm is output to the alarm device 37 ° in the case of the casting leakage preventing device of FIG. 12 or FIG. 13, the casting leakage determining means 098106495 61 200946265 33 can further output the casting to the control means 35. The type of danger that is leaking. For example, regarding the above α 1 , α 2 , 0, the notification signal is output, and the notification signal means that it is in a dangerous area where the exhaust heat is insufficient to cast (Ql &lt; α 1 and Q2 &lt; call), or is in a re-melting casting In the dangerous area of the leak and the call of Q2) or in the dangerous area of the two (Q1 &lt; α 1 and cold). When the control means 35 inputs a signal from the casting leakage determining means 33, for example, control for lowering the casting speed and lowering the flow rate of the molten steel is performed. As the control for lowering the casting speed, specifically, the control means 35 outputs a signal for instructing the pinch roller control means 27 to slow down the rotational speed of the motor 25. The pinch roller control device 27 to which the signal is input is controlled to reduce the number of revolutions of the motor 25. By lowering the rotational speed of the motor 25 and lowering the casting speed, the solidified shell thickness in the mold 1 becomes thicker, so that the risk of casting leakage can be avoided. As a control for lowering the flow rate of the molten steel, specifically, the control means 35 applies a 直s number to the electromagnetic brake device 41 to output a linear magnetic field such as a flow rate of the molten steel in the mold 1. If the signal is rotated, a DC base field is applied to the mold 1 by the electromagnetic brake device 41, and the flow rate of the molten steel in the mold is lowered. When the flow rate is lowered, the speed of the smashing gambling interface is lowered, and the degree of remelting of the solidified shell becomes small, so that the thickness of the shell is still thickened to avoid the risk of casting leakage. In the case where the casting leakage is prevented in the case of Fig. 12, the more detailed processing as described below may be performed in accordance with the above-described determination using αΐ α2 /3. 098106495 200946265 When the control means 35 inputs the signal from the cast-drain determination means 33, when the signal is based on Ql &lt; α 1 and Q22 β, the case is caused by the occurrence of exhaustion-deficient casting leakage and re-melting property. The situation of the danger of casting both of them is therefore controlled so that the casting speed is lowered and the flow rate of the molten steel is lowered. As a control for lowering the casting speed, specifically, the control means 35 outputs a signal indicating that the rotational speed Ο of the motor 25 is slowed down to the inflame-feeding roller control device 27. The pinch roller control device 27 to which the signal is input is controlled to reduce the number of revolutions of the motor 25. By lowering the rotation speed of the motor 25 and lowering the casting speed, the solidified shell thickness in the mold 1 becomes thicker, so that the risk of the exhaustion of the exhaust heat is prevented. As a control for lowering the flow rate of the molten steel, specifically, the control means 35 outputs a signal to the electromagnetic brake device 41 to apply a DC magnetic field such that the flow velocity of the molten steel in the mold is lowered, and if the signal is output, electromagnetic The brake device 41 applies a DC magnetic field to the mold 1 to lower the flow rate of the molten steel in the pound mold 1. If the flow rate of the molten steel is lowered, the speed at which the molten steel impacts the solidified shell interface is lowered, and the reduction of the remelting of the solidified shell is small, so that the risk of casting leakage due to re-dissolution of the shell can be avoided. Further, when the signal from the casting-drain determining means 33 is based on qi < α 1 and the case of receiving the stone, the situation is caused by the risk of causing the exhaustion of the exhausting heat. Therefore, the control means 35 is light on the pinch. The control device 27 outputs a signal indicating that the rotational speed of the motor 25 is slowed down. As a result, the casting speed is lowered, and the solidified shell thickness in the mold 1 is thickened, so that the risk of insufficient heat-extracting casting leakage can be avoided. Further, when the signal from the casting leakage determining means 33 is based on the case, since the situation is in danger of generating remelting casting leakage, the control means 35 applies the output of the electromagnetic braking device 41 such as the pound mode. The signal of the DC magnetic field in which the flow rate of the molten steel in 1 is lowered, whereby the remelting casting leakage can be avoided as described above. Further, when the alarm device inputs a signal from the casting leakage determining means 33, an alarm is issued. In this way, the operator can be notified of the danger of creating a casting leak. Furthermore, of course, in Figs. 1, 12 and 13, the casting leakage detecting device is composed of the following: a thermocouple group composed of the thermocouple 17, a local heat flux calculation means 29, and a stable solidification interface heat input memory means. 31. Heat flux distribution calculation means 32 and casting leak determination means 33 (or further alarm means 37). Further, in Fig. 1, the solidified shell thickness estimating device, that is, the thermocouple group composed of the thermocouple 17, the local heat flux calculating means 29, the stable solidification interface heat input memory means 31, and the heat flux distribution are constituted by the following portions. The calculation means 32 and the solidified shell thickness calculation means 34. For example, using the continuous ballasting apparatus disclosed in Fig. 12, after operating very low carbon steel at a casting speed of 2.0 m/min, Q2 &lt; 4500 kJ/m2, but the value of Q1 is Q1 &lt; 15000 kJ/ M2, and there is a danger of heat-exhaust leakage. Therefore, after the manufacturing speed is reduced to 〇. 5 m/min, Q12 15000 kJ/m2 can obtain sufficient solidified shell friction, and can prevent the casting of 098106495 64 200946265. Further, after the solidified shell thickness is sufficiently thick, the casting speed is increased again, whereby high-speed casting can be performed. Further, after operating the ultra-low carbon steel at a casting speed of 2.5 m/min using the continuous pounding apparatus disclosed in Fig. 12, the value of Q1 is 15000 kJ/m2 SQ1S21000 kJ/m2, and the value of Q2 is Q224500 kJ/m2, and there is a danger of remelting casting leakage. Therefore, the electromagnetic brake rupture 41 can be actuated to lower the value of Q2 to a value of less than 4500 kJ/m2, and the occurrence of re-melting melt-casting can be prevented. Further, using the continuous casting equipment disclosed in FIG. 13, after the actual effect is not deviated from 15000 kJ/m2SQl$21000 kJ/m2, the ultra-low carbon steel is operated at a tungsten production speed of 20 m/min. The value of Q2/Q1 exceeds 〇. 25. Therefore, after the casting speed is lowered to 〇5 m/min, a sufficient solidified shell thickness can be obtained for Q2/Q1 &lt; 0. 25 ', and generation of scale leakage can be prevented. Further, after the solidified shell is thick enough, the casting speed is increased again, whereby high-speed casting can be performed. According to this embodiment, it is possible to determine the presence or absence of a risk of casting leakage based on the heat flux distribution directly related to the solidified shell thickness at the exit of the mold, or to obtain a mold exit directly related to the casting leakage based on the distribution. According to the thickness of the solidified shell, it is determined whether or not a casting leak occurs. Therefore, under various operating conditions, the occurrence of scale leakage can be predicted with high sensitivity, simplicity, and reliability, and the casting leakage can be surely prevented. Further, regarding the risk of casting leakage, it is also possible to determine whether the casting leakage is a remelting casting leak or a heat exhausting insufficient scale. L-l 098 098106495 65 200946265 The best prevention means can be selected. Furthermore, in the content or embodiment of the present invention described above, the method of obtaining the integrated value of the heat flux corresponding to the total heat flux or the size of the convex material according to the heat flux distribution is mainly The method of doing it in a geometric way is revealed. However, the present invention is not limited thereto, and for example, the total heat flux can also be obtained by integrating the map. (Industrial Applicability) In the present invention, 'the heat flux ql to the heat input to the solidification interface during the period from the furnace surface of the molten steel in the continuous casting to the exit of the mold is measured, and the heat is applied to the heat flux ql and The difference between the steady solidification interface heat input q2reg caused by the flow of molten steel in the mold under steady state (ql-q2reg), the heat flux distribution of the molten steel from the furnace bath surface to the exit of the mold is obtained, according to the heat flux distribution In order to determine whether or not there is a risk of occurrence of scale leakage, the occurrence of casting leakage can be predicted with high sensitivity, simplicity, and reliability under various operating conditions, and the casting leakage can be surely prevented. Further, the total heat flux 卯 and Q2 are obtained based on the heat flux distribution and analyzed, whereby the cause of each casting leak can be further determined, so that it can be appropriately used for the purpose of avoiding the occurrence of the casting leakage. Further, since the total heat flux Q1 is used or the thickness of the solidified shell at the exit of the mold is estimated using Q2, the solidified shell thickness can be estimated with high accuracy. As described above, the present invention exerts various excellent effects in the field of control of continuous casting. 098106495 66 200946265 [Brief Description of the Drawings] Fig. 1 is an explanatory view of a continuous casting apparatus provided with a casting leakage preventing device according to an embodiment of the present invention. In the case of embedding, it is a thermoelectric system, which is a thermoelectric system, and is a part of a mold for continuous casting in which a thermocouple is used. Fig. 3 is an explanatory view showing an example of a method of embedding the illustration of the means for solving the problem.

Fig. 4 is an explanatory view showing an example of the mounting position of the illustration of the means for solving the problem. Fig. 5 is a diagram for explaining an example of a means for solving the problem. An example of the relationship between the heat flux (vertical axis: J/s · m2) and the distance from the bath surface (horizontal axis: mm). Fig. 6 is an explanatory view for explaining a means for solving the problem, which is a graph showing a relationship between a molten steel flow velocity (vertical axis: m/s) and a distance from the furnace surface (horizontal axis: mm). Figure 7 is an explanatory diagram for explaining the means for solving the problem, which shows local heat flux ql (black circles) and (ql - q2reg) (white circles) (vertical axis: J/s · m2) A graph showing an example of the relationship between the distance of the bath surface (horizontal axis: mm). Fig. 8 is an explanatory view for explaining a means for solving the problem, and is an explanatory view showing an example of the area of the heat flux distribution indicated by a graph showing the relationship between the local heat flux and the distance from the bath surface. Figure 9 is an explanatory view for explaining the means for solving the problem, which is an area showing the heat flux distributions Q1 and Q2 represented by a graph showing the relationship between the local heat flux and the distance from the bath surface by the table 098106495 67 200946265. An explanatory diagram of an example of the method. Fig. 10 is an explanatory view showing an example of means for solving the problem, which is shown in a coordinate plane in which the horizontal axis is Q1 (kJ/m2) and the vertical axis is Q2 (kJ/m2). The numerical values shown are plotted, and the coordinate plane is divided into five regions in relation to the presence or absence of a casting leak. Fig. 11 is an explanatory view for explaining a means for solving the problem, which is a graph showing an example of the relationship between the casting speed and the average temperature in the thickness direction of the shell at the exit of the mold, and the vertical axis indicates the average temperature in the thickness direction of the mold outlet shell (°C). ), the horizontal axis represents the casting speed (m/min). Fig. 12 is an explanatory view showing a continuous casting apparatus provided with a casting leakage preventing device according to another embodiment of the present invention. Fig. 13 is an explanatory view showing a continuous casting apparatus provided with a casting leakage preventing device according to another embodiment of the present invention. [Main component symbol description] 1 Mold 3 Impregnation nozzle 5 Melting steel 7 Molding powder 9 Solidified shell 11 Molded copper plate 13 Cooling water passage 098106495 68 200946265 15 (Bottom of cooling water passage) Hole 17 Thermocouple 19 Casting 21 Guide roller 23 Pinch roller 25 Motor 27 Pinch roller control device ❹ 29 Local heat flux calculation means 31 Stable solidification interface Heat input memory means 32 Heat flux distribution calculation means 33 Cast leak determination means 33A Cast leak determination means body 34 Solidified shell thickness calculation Means 35 Control device 10 37 Alarm device 40 Feeding tank 41 Electromagnetic brake device 098106495 69

Claims (1)

200946265 VII. Scope of application for patents: 1. A method for detecting casting leakage in continuous casting, which comprises: determining the heat flux of the heat input to the solidification interface during the period from the furnace surface of the mold in the continuous casting to the exit of the mold The step of measuring ql; determining the stable solidification interface heat input q2reg caused by the flow of the molten steel in the mold under steady state according to the following formula (1); for the difference between the heat flux ql and the stable solidification interface heat input q2reg (ql(j2reg) 'determine the step of the molten steel from the furnace> the distribution of the heat through the valley to the exit of each die; and the step of determining the risk of casting leakage based on the heat flux distribution; q2reg=hA 0 .........(1) where h: the heat transfer coefficient Δ0 between the molten steel and the solidified shell: the superheat of the molten steel. 2. The casting of continuous casting as in the first application of the patent scope a leak detection method, wherein the step of determining whether there is a risk of casting leakage based on the heat flux distribution obtained for the above (q 1 - q 2 reg) includes: according to the heat flux distribution Find the total heat by the following method The steps of the quantities Q1 and Q2, that is, when there is a minimum point indicating the minimum value in the heat flux distribution, when the local heat flux value at the exit point of the mold is connected by a straight line, The total heat flux corresponding to the area above the straight line is set to 098106495 70 200946265 Q2, and the total heat flux corresponding to the area is set to be between the position from the bath surface and the exit of the mold. The total heat flux equivalent to the total area enclosed by the entire curve of the heat flux distribution minus the area obtained by female Q2, when there is no minimum point of the small value of the surface system in the heat flux distribution mentioned above, The total heat flux corresponding to the total area enclosed by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold is set as the total heat flux Q1 'the step of setting Q2 to zero; and ❹ The total heat flux qi, or the step of determining whether there is a risk of occurrence of a leak according to Q1 and Q2. 3. The method for detecting the casting leakage of continuous casting according to item 2 of the patent application, wherein the above determination determines whether or not a casting leak occurs. Dangerous In the middle of the step, Q1 is used as an index of heat removal caused by solidification, and Q2 is used as an index exceeding the steady heat input of the solidification interface. ❿ According to Q1 or according to Q1 and Q2, it is determined whether there is a risk of casting leakage. A continuous casting method for casting leak detection according to item 2 of the patent scope, wherein 'in the step of determining whether or not there is a risk of pound leakage based on the total heat flux Q1 described above, regarding the threshold α1 preset for Q1 , α 2), when Ql &lt; α 1, it is judged that there is a risk of casting leakage, and when a 1SQ1S α2, it is determined that there is a risk of casting leakage based on the value of Q2. 098106495 71 200946265 5·The method for detecting the casting leakage of continuous casting according to item 2 of the patent application scope, wherein there is a minimum point indicating the minimum value in the heat flux distribution obtained for the above (ql - q2reg) In the case, Ql&lt;al and Q22 are cold, or Ql&lt;al and Q relative to the pre-set thresholds α 1, α2 (α 1 &lt; α2) for Q1 and the pre-set threshold /3 for Q2 When Q2C/3, or α 1SQ1S α2 and Q2 2 /5, it is judged that there is a risk of scale leakage. 6. For the continuous casting method of casting and leak detection according to item 5 of the patent application scope, wherein the molten steel is extremely low carbon steel, αΐ is 15000 (kJ/m2), and α 2 is 21000 (kJ/m2), which is 4500 (kJ/m2). 7. The method for detecting a casting leak in continuous casting according to item 2 of the patent application, wherein the step of determining whether there is a risk of casting leakage based on the total heat flux Q1 described above includes: using the total heat flux Q1 ' The following formula (2) is a step of estimating the thickness D of the solidified shell at the exit of the mold; and determining the thickness of the solidified shell J) estimated above and the threshold value obtained in advance in relation to the risk of casting leakage Whether there is a risk of casting leakage; D=Q1/(AH · P ) .........(2) 098106495 72 200946265 where D: solidified shell thickness at the exit of the mold (m) Q1 : total Heat flux (W) ΔΗ . The drop per unit weight of the solidified shell at D is (j/kg) p: the solidified shell density of the mold D (kg/m3). J/s · m2 , in the above formula (丨), the unit of q2reg is set to J/s · in2, and the unit of h is set to J/s · m2 · It sets the unit of ΔΘ. c. ❹ 8. A method for detecting a casting leak in continuous casting according to item 2 of the patent application, wherein when there is a minimum point indicating a minimum value in the heat flux distribution obtained for the above (ql - q2reg) The step of determining whether or not there is a risk of casting leakage based on the total heat fluxes Q1 and Q2 described above includes the steps of: estimating the thickness D of the solidified shell at the exit of the mold according to the following formula (2) using the above total heat flux Q1. Using the solidification delay degree RS obtained according to the following formula (3), the step of deriving the solidified shell thickness D1 considering the solidification delay by the relationship of = D(l - RS), which is caused by the total The remelting caused by the heat flux Q2 is generated by the producer; and the thickness of the solidified shell D1 estimated above and the threshold value obtained in advance in relation to the risk of casting leakage are determined to determine whether or not a casting leak occurs. Dangerous step; 098106495 73 200946265 D = Q1/(AH · p ) (2) where D: the thickness of the solidified shell at the exit of the mold (m) Q1 : total heat flux ( J/m2) ΔΗ : the drop per unit weight of the solidified shell at the exit of the mold (J/kg) P: solidified shell density of the pound die exit (kg/m3) RS= ySx(VO 8.A0 ) (3) where RS: solidification delay (no unit) /3: solidification Delay constant (no unit) V: Melt flow rate (m/s) Δ0: Fused steel superheat (°C) Here, V=(Q2/(a · t · Δ0 )) 1.25 Q2 : Total heat flux ( J/m2) α : steelmaking flow rate constant (no unit) t: time required for the solidified shell to reach the exit of the mold through a very small point in the heat flux distribution (S) Further, the unit of the above ql is set to J/ s · m2, in the above formula (1), the unit of q2reg is J/s · m2, and the unit of h is J/s · m2 · °C, and the unit of A0 is set. C. 9. The method for detecting a casting leak in continuous casting according to item 2 of the patent application, wherein when there is no minimum point indicating a minimum value in the heat flux distribution obtained for the above (ql - q2reg) According to the method of claim 7 098106495 74 200946265, the thickness of the solidified shell at the exit of the mold is estimated, and 8 of the above-mentioned heat flux distributions obtained for the above (ql - q2res) represent a minimum value. In the case of a very small point, the thickness of the solidified shell at the exit of the mold is estimated as in the method of the patent application. 10. The method according to any one of claims 1 to 6, wherein the heat flux ql is set in the casting direction of the mold to form a plurality of pairs of thermoelectric ❹ couples according to the above The local heat flux obtained by the following equation (4) is the output of a pair of thermocouples. The pair of thermocouples are buried between the two points in the mold in the thickness direction of the mold, ql= λ (Tl-T2)/d ... (4) where ' Λ : thermal conductivity of the mold ΤΙ ' Τ 2 : detection temperature of the thermocouple d: buried interval of the thermocouple. ❹ 11. The method for detecting a continuous casting of a casting casting according to any one of claims 7 to 9, wherein the heat flux ql is a plurality of pairs of thermocouples in the casting direction of the casting mold, according to the above- For the input of the thermocouple, the local heat flux obtained by the following formula (4) is the same as that between the two points where the depth of the thermocouple is buried in the mold (4) in the thickness direction of the mold, ql=A(Tl ~T2)/d ... (4) where ' λ : thermal conductivity of the mold (J/s · m · 〇 098106495 75 200946265 Π, Τ 2 : detection temperature of the thermocouple (° C) d: embedding interval (m) of the thermocouple 12. A continuous casting casting leak detection device comprising: a thermocouple group formed by placing a plurality of thermocouples in a casting direction of the mold, A pair of thermocouples are embedded in two points with different depths in the thickness direction of the mold; local heat flux calculation means, inputting temperature information from the thermocouple group to obtain local heat flux ql of each thermocouple setting portion ; Stable solidification interface heat input memory means, memory is obtained according to the following formula (1) The data of the stable solidification interface heat input Cj2reg caused by the flow of molten steel in the mold under steady state, the distribution calculation means, for the difference between the heat flux ql and the stable solidification interface heat input q2reg (ql - q2reg), obtain the melting The heat flux distribution of the steel from the bath surface to the exit of the mold; and the method of determining the casting leakage, according to the obtained heat flux distribution to determine whether there is a risk of praying; q2reg = h · Δ Θ ..... .... (1) where h is the heat transfer coefficient A0 between the molten steel and the solidified shell: the superheat of the molten steel. 13. The continuous casting casting leak detection device according to the scope of claim 12, wherein The casting leakage determining means is as follows: 098106495 76 200946265 According to the heat flux distribution described above, the total heat fluxes Q1 and Q2 are obtained by the following method: that is, there is a minimum point indicating the minimum value in the heat flux distribution. In the case where the local heat flux value at the exit of the mold is connected by a straight line, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2, and the total heat equivalent to the following area is used. The flux is set to Q1, The area is obtained from the total heat flux corresponding to the total area enclosed by the entire curve φ of the heat flux distribution from the position of the bath surface to the exit of the mold minus the area obtained by Q2, in the heat flux distribution When there is no minimum point indicating a minimum value, the total heat flux corresponding to the total area surrounded by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold is set as the total heat flux. The quantity Q1 sets Q2 to zero, and determines whether or not there is a risk of casting leakage based on the total heat flux Q1 described above or based on Q1 and Q2. ❿ 14. The casting and leak detecting device for continuous casting according to Item 13 of the patent application, wherein the casting leakage determining means is as follows: the total heat flux Q1 is used as an index of heat generation caused by - solidification, According to the need, Q2 is used as an indicator of heat input exceeding the stable solidification interface. According to Q1 or according to Q1 and Q2, the risk of casting leakage is determined. 15. The casting and leak detecting device for continuous casting according to claim 13 of the patent application, wherein 098106495 77 200946265 the above-mentioned casting leakage determining means is as follows: relative to a preset value α set for the total heat flux Q1 described above 1, 1 / η, "B, α 1 &lt; α 2), when Ql &lt; al, it is judged that there is a risk of casting leakage, when QlSa 2 is determined, 'the risk of turning off is judged based on the value of Q2. - 16. The casting leakage detecting device according to the thirteenth aspect of the patent application, wherein the casting leakage determining means is as follows: in the heat flux distribution obtained for the (4) "heart" When there is a case where the minimum value indicating the minimum value exists, ❹ is cold relative to the threshold values α1, α2 (α1 &lt; α2) preset for Q1 and the threshold value set for Q2, when Q1 &lt; α丨 and Q2g a, or Ql&lt;al and Q2&lt;々' or Q2^/5, it is judged that there is a danger of casting leakage. Π_ As for the continuous casting casting leak detection device of claim 16 of the patent application, wherein When steel is extremely low carbon steel, set α 1 to 15000 (kJ/m2), and α2 It is set to 21000 (kJ/m2), and the cold is set to 4500 (kJ/m2). 18. The continuous casting of the pound leak detecting device according to claim 13 of the patent application scope, wherein the casting leakage determining means includes: solidification The shell thickness calculation means, using the total heat flux Q1, calculates the solidified shell thickness D at the exit of the mold according to the following formula (2); and 098106495 78 200946265 The main body of the trapping determination means, the operation of inputting the solidified shell thickness calculation means The value 'determines whether or not there is a risk of casting leakage based on the calculated value D and the threshold value obtained in advance in relation to the risk of occurrence of casting leakage; D = Q1/(ah · p )... (2) where D: the thickness of the solidified shell at the exit of the mold Qi: total heat flux (j/m2) △Η: the drop per unit weight of the solidified shell at the exit of the mold (J/kg) P : The solidified shell density (kg/m3) at the exit of the mold is set to J/s.m2. In the above formula (1), the unit of q2reg is set to J/s · y, and the unit of h is set. For J/s · y · death, set the unit of △ 0 to .C. 19 · Continuous casting casting leak detection device as claimed in item 13 of the patent application Wherein the leak determination means for casting comprising: The solidified shell thickness calculation means calculates the solidified shell thickness D at the exit of the mold according to the following formula (2) using the total heat flux Q1, and further uses the solidification delay degree RS obtained according to the following 弋(3). The relationship between D1 = D(1 - RS): calculated by considering the solidification shell thickness D1 of the solidification delay, which is caused by re-dissolution caused by the total heat flux Q2; The body, the input value of the solid-shell thickness calculation means "value" is determined according to the above-mentioned calculated value D1 and the threshold value obtained in advance with the risk calculation system for generating the casting leak; and 408106495 79 200946265 D = Q1/(AH · p) (2) where D is the thickness of the solidified shell at the exit of the mold (m) Q1 : total heat flux (J/m2) AH: mold exit The enthalpy drop per unit weight of the solidified shell at the place (J/kg) p : the solidified shell density at the exit of the mold (kg/m3) RS= /3χ(ν°·8·Δ6» ) ........ (3) where RS: solidification delay (no unit) point: solidification delay constant (no unit) V: molten steel flow rate (m/s) A0: molten steel superheat (°C) Here, V=(Q2 /(a · t · Δ0 )) 125 Q2 : total heat flux (J/m2) α : steelmaking flow rate constant (no unit) t: time required for the solidified shell to reach the mold exit after passing through a very small point in the heat flux distribution (S) Further, the unit of the above ql is J/s · m2, and in the above formula (1), the unit of q2reg is J/s · m2, and the unit of h is J/s · m2 · °C, set the unit of ΛΘ to °C. 20. The continuous casting casting leak detecting device according to claim 13 wherein the solidified shell thickness calculating means is as follows: the heat flux distribution obtained for the above (ql - q2reg) does not exist. 098106495 80 200946265 In the case of the minimum point indicating the minimum value, the thickness of the solidified shell at the exit of the mold is calculated by the method of __ Μ 如, as described above for the above heat flux (D) When there is a case where the minimum value of the table is not extremely small, the thickness of the solidified shell at the exit of the mold is calculated by the method of the 19th item. The device uses the casting and leak detecting device of any one of claims 12 to 20; ❹ it includes (4) means, and the means for driving is determined to have a prayer in the casting leakage determination means In the case of a dangerous danger of leakage, the second drop: the control of the operating condition in the manner of casting speed, or the control of lowering the flow rate of the molten steel in the mold in addition to the control material. D./2. A casting and leakage preventing device for continuous casting, system The use of the leak detection device of any of the items 12 to 20 of the patent application; ❹ includes a control means, and the control means inputs the mark of the casting leakage determination means, when the casting leakage determination means determines that the material leakage In the case of danger, the control is carried out in such a manner as to slow down the speed of the scale. 23. A continuous casting casting leakage preventing device which uses the casting leakage detecting device of the patent application No. 16 or π; There is a control means, and the control means inputs the signal of the casting leakage determining means, and the casting leakage determining means determines that there is a risk of casting leakage. Although the determination of the danger of the temperature is based on the risk determination of Ql &lt; α 1 and Q2g ys At the time of 'reducing the shank speed and / or increasing the mode cooling, the operation bar 098106495 200946265 =, or in addition to the control, the control of the (4) in-mold continuation descent is based on Ql &lt; and Q2 &lt; red danger _ Timing, r-down speed and / or enhanced mold cooling to control the operating conditions; a ^ - when based on the risk of 2 and Q2, the flow rate of the molten steel in the mold is reduced or the casting speed is further reduced Degree and enthalpy or enhanced control of mold cooling. 曰24. - Continuous casting method of steel, which is the method for the detection of the number of pounds of the fourth item, so that Q1 &gt; α 2, or In order to make "1 mold $ α 2 and make Q2 a reduced value that is not determined to have the risk of casting leakage, control the operating conditions. 25. - The method of making steel is to use For the casting and leak detection method of the fifth or sixth patent range, 乂 becomes Ql&gt;a2 and Q2g万, or the square 控制 control private condition. 26. The continuous casting method of steel according to claim 25 , in which, in operation, Tian ei &lt;al and 'Wan Shi' control the operating conditions in a manner that reduces the speed of prayer and/or enhances Hao Leng Ge' or in addition to the control, so as to catch the steel in the prayer mold The mode of descent controls the operating conditions; Tian Ql &lt;orI and Q2&lt;/9, control the operating conditions by reducing the casting speed and/or enhancing the cooling mode of the pound model 098106495 82 200946265; although alSQl$a2 and Q22 million, to mold The flow rate of the molten steel inside drops 'or further reduces the casting speed / Or enhance embodiment of the mold cooling control operation conditions. 27. The method of continuous casting of steel according to claim 24, wherein the heat flux ql is a plurality of thermocouples arranged in the casting direction of the mold. Occasionally, according to the output of the pair of thermocouples, the local heat flux obtained by the following formula (4) is two points in which the pair of thermocouples are buried in the mold in the thickness direction of the mold. Between, ql= A(Tl-T2)/d (4) where λ: thermal conductivity of the mold ΤΙ, Τ 2: detection temperature of the thermocouple d: embedding interval of the thermocouple. 28. A continuous casting method for a steel, which uses the method for detecting a scale leak according to any one of claims 7 to 9; such that the thickness of the estimated solidified shell is greater than that of the prior The operating conditions are controlled in such a way that the dangerous relationship is determined by the threshold. 29. A method for estimating the thickness of a solidified shell of continuous casting, comprising the step of determining a heat flux ql of heat input to the solidification interface during the period from the furnace surface of the molten steel in the mold to the die-cutting in the continuous casting; The following step (1) is a step of obtaining a stable solidification interface heat input q2reg of a molten steel flow in a mold under steady state; 098106495 83 200946265 such heat flux ql (J/s · m2) and stable solidification interface heat Enter the difference of q2reg (ql - q2reg) to obtain the heat flux distribution from the furnace surface to the exit of the mold; and when there is a minimum point indicating the minimum value in the heat flux distribution described above, When a local heat flux value at the exit point of the mold is connected by a straight line, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2, and the total heat flux corresponding to the following area is set to Q1, the area is the total heat flux corresponding to the total area enclosed by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold minus the area obtained by Q2, the heat flux Does not exist in the distribution When the minimum value of the minimum value is expressed, the total heat flux corresponding to the total area surrounded by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold is set as the total heat flux Q1, Using the total heat flux Q1, the step of estimating the solidified shell thickness D at the exit of the mold according to the following formula (2); Q2reg - h * Δ 0 .........Ο) where q2reg : stable Solidification interface heat input (J/s · m2) h : heat transfer coefficient between molten steel and solidified shell (J/s · m2 · °C) Αθ: superheat of molten steel fC) D = Q1/(AH · p ) (2) where D is the solidified shell thickness at the exit of the mold (m) Q1 : total heat flux (J/m2) AH : per unit of the solidified shell at the exit of the mold Weight drop (J/kg) 098106495 84 200946265 p : solidified shell density (kg/m3) at the exit of the mold. 30. A method for estimating the thickness of a solidified shell of continuous casting, which is based on the case where there is a minimum point indicating a minimum value in the heat flux distribution, and it is estimated that the solidification shell thickness D1 considering the solidification delay is caused by the total If the solidified shell thickness obtained by the heat flux Q2 is taken as D, then D1 = D(1-RS), ❹ where RS= ySx(VD8- A0 ) .........(3) RS : Solidification delay (no unit) Stone: Solidification delay constant (no unit) V : Melt flow rate (m/s) A0 : Fused steel superheat (° C) Here, V = (Q2 / (a · t · Δ0 )) 125 Q2 : total heat flux (J / m2) 10 α : molten steel flow rate constant (no unit) t: solidified shell through the heat flux distribution The time (S) required to reach the exit of the mold after a very small point. * 31. A method for estimating the thickness of a solidified shell for continuous casting, comprising: a step of determining a heat flux ql of heat input to a solidification interface during a period from a furnace bath surface of the molten steel in the continuous casting to a mold exit; The step of stabilizing the solidification interface heat input q2reg caused by the flow of the molten steel in the mold under steady state is obtained according to the following formula (1); 098106495 85 200946265 and the heat flux ql (J/s · m2) and stable solidification The difference between the interface heat input q2reg (ql-q2reg), the step of obtaining the heat flux distribution of the molten steel from the furnace bath surface to the exit of the mold; and the step of estimating the thickness of the solidified shell according to the heat flux distribution; When there is no minimum point indicating the minimum value in the heat flux distribution, the method of claim 29 is used to estimate the thickness of the solidified shell. When there is a minimum point indicating the minimum value in the heat flux distribution, the patent application scope is utilized. The method of item 30 is to estimate the thickness of the solidified shell. The method for estimating a solidified shell thickness of a continuous casting according to any one of claims 29 to 31, wherein the heat flux ql is a plurality of pairs of thermocouples in a casting direction of the mold, according to the pair The local heat flux obtained by the following equation (4) is the output of the thermocouple, and the pair of thermocouples are buried in the mold in between the two points of different depths in the thickness direction of the mold, ql=λ ( Tl-T2)/d (4) where ql : heat flux (J/s · m2) λ : thermal conductivity of the mold (J/s · m · °C ) Π , T2 : detection temperature of thermocouple (°C) d : embedding interval (m) of thermocouple. 33. A continuously casting solidified shell thickness estimating device comprising: a thermocouple group formed by providing a plurality of thermocouples in a casting direction of the mold, the pair of thermocouples being embedded in a depth in a thickness direction of the mold 098106495 86 200946265 The same two points; local heat flux calculation means, input the temperature information from the thermocouple group to obtain the local heat flux ql of each thermocouple setting part; stable solidification interface heat input memory means, memory According to the following formula (1), the steady solidification interface heat input caused by the molten steel flow in the mold under steady state is obtained (j2reg data, distribution calculation means, for the heat flux ql and the stable solidification interface heat input) The difference between q2reg (ql - q2reg), the heat flux distribution of the molten steel from the furnace surface to the exit of the mold; and the calculation method of the solidified shell thickness, in the heat flux distribution obtained by the distribution operation means When there is no minimum point indicating the minimum value, the total curve surrounded by the heat flux distribution from the position of the bath surface to the exit of the mold is not present. The total heat flux corresponding to the area is set to the total heat flux Q1, and when there is a case where the minimum value of the minimum value is small in the heat flux distribution obtained by the above-mentioned distribution operation means, when the line is connected by the line When the point is at the local heat flux value at the exit of the mold, the total heat flux corresponding to the area of the upper portion of the straight line is set to Q2, and the total heat flux corresponding to the following area is set to Q1, which is Using the total heat flux Q1 from the total heat flux equivalent to the total area enclosed by the entire curve of the heat flux distribution from the position of the bath surface to the exit of the mold, using the total heat flux Q1, The following formula (2) calculates the solidified shell thickness D at the exit of the mold; q2reg:=h · Δ Θ .........(1) 098106495 87 200946265 where q2reg : stable solidification interface heat input (J /s · m2) h : heat transfer coefficient between molten steel and solidified shell (J/s · m2 · °C) Δ0 : superheat of molten steel (°C) D = Ql/(AH.p) .. (2) where D: the thickness of the solidified shell at the exit of the mold (m) Q1: total heat flux (J/m2) ΔΗ : each of the solidified shells at the exit of the mold The weight drop of the bit weight (J/kg) p : the solidified shell density (kg/m3) at the exit of the mold. 34. The solidified shell thickness estimating device for continuous casting according to the scope of claim 33, wherein the solidified shell thickness calculation means The thickness of the solidified shell considering the solidification delay is taken as D. The solidification delay is caused by the remelting caused by the total heat flux Q2, so that D1 = D(1-RS), where RS = 5χ(ν° ·8·Α0 ) .........(3) Cold: solidification delay constant (no unit) V: molten steel flow rate (m/s) A0: molten steel superheat (°C) RS: solidification delay Degree (no unit) Here, V=(Q2/(a · t · Δ0 )) 125 Q2 : total heat flux (J/m2) α : molten steel flow rate constant (no unit) t: solidified shell through heat flux The minimum point in the quantity distribution reaches the exit of the mold 098106495 88 200946265 Time required (s). 35. A continuous casting solidified shell thickness estimating device, comprising: a thermocouple group 'formed in a plurality of pairs of thermocouples in a casting direction of the mold, the pair of thermocouples being buried in a depth direction of the mold Two different points; the local heat flux calculation means 'transfers the temperature information from the thermocouple group and obtains the local heat flux ql of each thermocouple setting part; ❹稳钱ID界 Φ heat input memory means' According to the following formula (1), the steady solidification interface heat input caused by the molten steel flow in the mold under steady state is obtained (j2reg data; the difference between the knife cloth operation hand &amp; Lin et al. minus 1 ql and the stable (four) interface heat input q2reg ( Ql — q2reg) 'Get the heat flux distribution of the molten steel from the bath surface to the exit of the prayer mode; and The solidified shell thickness transport section, (4) (4) The heat flux distribution obtained by the split section is calculated by calculating the condensation_thickness d at the outlet; and the above solidification shell thickness calculation means is as follows, when the heat flux distribution is When there is no minimum point indicating the minimum value, the method of applying the patent (4), item 33, is used to calculate the thickness _ of the shell. When the heat flux f distribution has a small amount of small values, the amount of the patent is used. The method of item 34 is to operate on the shell thickness di. 098106495 89