JP3235524B2 - Casting bulging detection method, bulging determination method, bulging prevention method, and apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting, judging and preventing slab bulging in a continuous casting facility.

[0002]

2. Description of the Related Art In continuous casting, molten steel in a ladle is continuously cast into a mold via a tundish, and a solidified shell is formed around the molten steel by a water-cooled mold. While supporting the solidified shell in the roll group and the pinch roll band, the solidified shell is grown by cooling spray between the rolls, and a completely solidified slab drawn by the pinch roll is cut into a predetermined length by a torch cart.

[0003] In such continuous casting equipment, a slab that solidifies completely after the end of the pinch roll machine does not have a constraining roll, and therefore excessively expands (bulging) due to static iron pressure in the slab and does not pass through the torch truck. In this case, the equipment is damaged (see FIG. 6A). On the other hand, the distance from the pinch roll to the torch truck is generally about 1 m to 10 m, and the occurrence of excessive expansion slabs is noticed. It is necessary to detect in the belt to prevent accidents.

As a method for detecting bulging between rolls of a slab, the following various methods have been conventionally proposed, but each has the following problems and disadvantages.

[A] Direct type (1) Contact type (1-1) Roller contact type As disclosed in Japanese Patent Application Laid-Open No. Hei 3-71961, a roller is directly applied to a slab to displace the slab surface. How to measure. Low measurement accuracy due to slippage, deformation, poor rotation, thermal effects, etc.

(2) Non-contact type (2-1) Projection type As disclosed in Japanese Patent Application Laid-Open No. 58-176510, a method of projecting with a parallel light source to detect bulging of a short side of a slab. The shape projected on the light receiver is easily affected by heat, interference waves, and water vapor, and cannot be quantitatively determined.

(2-2) Ultrasonic type JP-A-61-57550, JP-A-5-57414
As disclosed in JP-A-6-328213 and JP-A-6-328213, an ultrasonic system in which spray water is used to irradiate ultrasonic waves. This method is relatively inexpensive and has little thermal effect, but uses water to result in uneven cooling of the slab. In order to measure a small displacement, it is necessary to use a high frequency and a short distance.

(2-3) Eddy current type JP-A-53-113222, JP-A-63-104
No. 767, Japanese Unexamined Patent Publication No. 3-268850, etc., the object distance is set to 200 mm with an eddy current rangefinder.
How to measure the displacement while keeping the degree. It cannot be measured in an environment containing a lot of water. It is necessary to install the device at the shortest distance from the object, and the cost for heat insulation is high.

[B] Indirect type (1) Roll load measurement type JP-A-55-88961, JP-A-6-32821
A method of indirectly measuring the amount of roll deflection and further performing feedback control of a motor drive current as disclosed in Japanese Patent Publication No. 3 (1993). There are many indirect factors and bulging displacement cannot be specified.

Although the above-mentioned conventional methods have advantages and disadvantages, what is common in each of the conventional methods is that the play of the machine is also detected as the bulging amount, and the value detected by the sensor cannot be specified as the bulging. In addition, this method is a low-measurement method and cannot accurately measure minute bulging between rolls.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to accurately detect minute bulging between rolls, and to quickly and accurately detect dangerous bulging. It is an object of the present invention to provide a method and an apparatus thereof that can detect an accident or the like and prevent an accident due to slab bulging beforehand.

[0012]

The bulging detection method of the present invention is a method for detecting bulging between rolls of a slab in a continuous casting facility, and uses a non-contact type distance sensor (such as a laser sensor) to detect the bulging between rolls. slab top of off
The displacement relative to the frame, the displacement of the upper surface of the roll close to the upper surface of the slab relative to the frame, and the displacement of the frame of the roll relative to the fixed member independent of the frame are measured. A true inter-roll bulging amount is obtained by subtracting the measured value and the measured frame displacement value (claim 1).
In a guide roll group or a pinch roll band, mechanical play such as roll bending / bending, bearing gap, frame hydraulic displacement / mechanical gap, and the like can be offset, and true inter-roll bulging can be accurately detected.

The bulging determination method of the present invention is a method of determining bulging between slab rolls of a slab in a continuous casting facility. The displacement of the upper surface of the slab between the rolls with respect to a frame by a non-contact type distance sensor is determined by using a non-contact type distance sensor. The displacement of the roll upper surface close to the upper surface relative to the frame and the displacement of the roll frame relative to a fixed member independent of the frame are measured, and the measured displacement of the upper surface of the roll is measured from the measured displacement of the upper surface of the slab. And the true inter-roll bulging amount is obtained by subtracting the measured value of the frame displacement, and the inter-roll bulging amount is obtained by calculating the relationship between the previously obtained inter-roll bulging amount and the slab width, the casting speed or the slab carbon amount. When any one of the determination criteria calculated by the relational expressions is exceeded, it is determined to be dangerous bulging (claim 2). In the guide roll group or the pinch roll band, dangerous bulging can be easily and accurately detected at an early stage based on accurate bulging between rolls.

The bulging preventing method according to the present invention is a method for preventing bulging between slab rolls of a slab in a continuous casting facility. The displacement of the upper surface of the slab between the rolls with respect to the frame by means of a non-contact type distance sensor is determined by the following method. The displacement of the roll upper surface close to the upper surface relative to the frame and the displacement of the roll frame relative to a fixed member independent of the frame are measured, and the measured displacement of the upper surface of the roll is measured from the measured displacement of the upper surface of the slab. The true inter-roll bulging amount is obtained by subtracting the measured value of the frame displacement and the roll bulging amount, and the relationship between the previously determined bulging amount between the rolls and the slab width, the casting speed or the slab carbon amount is calculated. If any one of the criterion calculated by the relational expression is exceeded, it is judged as dangerous bulging and the casting condition is changed to reduce the bulging amount. Characterized by (claim 3).
By measuring the bulging between rolls in the pinch roll band and changing the casting conditions (casting speed, spray cooling water amount, etc.), excessive bulging can be suppressed, and damage to equipment after the pinch roll band can be prevented. .
In addition to the pinch roll band, by measuring bulging between rolls in the guide roll group on the upstream side and changing casting conditions (casting speed, molten metal injection speed, etc.), fluctuations in the level of the molten metal in the mold can be reduced. Can be prevented.

The bulging detection device of the present invention is a device for detecting bulging between slabs of a slab in a continuous casting facility, and comprises a non-contact type distance sensor for measuring a displacement of the upper surface of the slab between the rolls with respect to a frame. a non-contact distance sensor for measuring the displacement with respect to roll the upper surface of the frame close to the slab top surface, deflection of the frame of the roll
A non-contact distance sensor that measures displacement relative to the fixed member independent of the ram, a device that blows gas at the measurement point on the top of the slab, a displacement measurement value on the roll top and a frame from the displacement measurement on the slab top And an arithmetic processing unit (such as a personal computer) for calculating a true inter-roll bulging amount by subtracting the displacement measurement value of the above-mentioned (claim 4).

The bulging determination apparatus of the present invention is an apparatus for determining bulging between slabs of a slab in a continuous casting facility, and includes a non-contact type distance sensor for measuring a displacement of the upper surface of the slab between the rolls with respect to a frame. a non-contact distance sensor for measuring the displacement with respect to roll the upper surface of the frame close to the slab top surface, deflection of the frame of the roll
A non-contact distance sensor that measures displacement relative to the fixed member independent of the ram, a device that blows gas at the measurement point on the top of the slab, a displacement measurement value on the roll top and a frame from the displacement measurement on the slab top The true inter-roll bulging amount is obtained by subtracting the measured displacement value of the roll, and the relation between the roll bulging amount and the slab width, the casting slab width, the casting speed or the slab carbon amount obtained in advance is obtained. An arithmetic processing unit (a personal computer or the like) for determining a dangerous bulging when any one of the determination criteria calculated by the formulas is exceeded is provided (claim 5).

The bulging prevention apparatus of the present invention is an apparatus for preventing slab bulging of a slab in a continuous casting facility, and comprises a non-contact type distance sensor for measuring a displacement of a slab upper surface between rolls with respect to a frame. a non-contact distance sensor for measuring the displacement with respect to roll the upper surface of the frame close to the slab top surface, deflection of the frame of the roll
A non-contact type distance sensor that measures displacement relative to the fixed member independent of the dome, a device that blows the measurement point on the slab upper surface with gas, a displacement measurement value on the roll upper surface from the displacement measurement value on the slab upper surface, and The true inter-roll bulging amount is obtained by subtracting the frame displacement measurement value, and the inter-roll bulging amount represents the relationship between the previously obtained inter-roll bulging amount and the slab width, the casting speed or the slab carbon amount. If any one of the criterion calculated by the relational expression is exceeded, it is determined that dangerous bulging is performed, and an arithmetic processing device (such as a personal computer) is provided which suppresses bulging by changing casting conditions. (Claim 6).

(1) Components and Functions of Device of the Present Invention As shown in FIG. 1 and Table 1, components and functions of the device of the present invention mainly include a non-contact high-resolution sensor 1 and a sensor mount 2. , An amplifier box 3, a personal computer 4, a bulging determination program 5, and a specific water volume control 6.

[0019]

[Table 1]

The high-resolution sensor 1 is, for example, of a laser type and, in the case of a sensor for detecting the upper surface of a slab, via the sensor mount 2 at a position (normally the center in the slab width direction) where maximum bulging is expected to occur. And irradiate a laser from the sensor head to measure perpendicular to the top surface of the slab. In the case of a laser, the irradiated laser collides with the slab, becomes diffuse reflected light, passes through a filter that can transmit only a specific wavelength band, is focused on the photodiode by a light receiving lens, and is transmitted from the photodiode to the light receiving circuit. You. The information of the transmitting circuit is compared with the phase difference of the light receiving circuit, AD conversion is performed, and current and voltage are output. This output waveform is amplified by an amplifier, and the shortest frequency 5Hz (200msec) ~
The distance is measured at a continuous cycle of about 1 KHz (1 sec),
As will be described in detail later, the detected waveform is calculated and displayed in the personal computer, and when bulging is determined, an alarm / screen is displayed and the casting speed is reduced or the specific water amount is increased.

Table 2 shows a comparison with the conventional sensor. The laser method is the most effective, and can solve all the problems of the conventional sensors listed above.
Particularly, when a red laser is used, the sensor head can be made compact because the wavelength is long. Further, since it is a light emitting body on the surface of the cast slab and has a temperature of 800 to 1000 ° C., the wavelength is about 770 nm. Normally, when using a red laser displacement meter, the laser wavelength is 550 to 700 nm,
Although an interference wave is assumed, a sensor having a filter that does not transmit a wavelength band other than the self-emission light is commercially available.

[0022]

[Table 2]

(2) Detection of Inter-Roll Bulging In order to detect minute inter-roll bulging of a slab,
It is necessary to convert to a value in which the displacement of the constituting mechanical parts is offset. Therefore, in the present invention, a calculation program for simultaneously measuring the displacement and deflection of the roll and the frame and converting the bulging amount between the rolls into the relative displacement from the displaced (deformed) roll lower surface is created, and the following equation (1) is obtained. To determine the true inter-roll bulging amount δ ^* .

[0024]

(Equation 1) As an example, as shown in FIG.
5 is the displacement of the upper surface of the slab with respect to the lower surface of the upper roll 14.
Is based on b is the upper part of the upper frame 15
This is the displacement of the upper surface of the roll 14. c is the upper frame 1
5 (see Fig. 1 (a))
Is the displacement of the upper frame 15.

Here, the following two methods are conceivable for detecting the displacement of the upper surface of the slab by the relative displacement from the lower surface of the roll. A method in which the slab top surface displacement is measured using only the slab displacement measurement sensor installed at a place where the frame is not displaced by the static iron pressure, and the center of the amplitude of the displacement is assumed to be the bulging amount. As in the present invention, three displacements are measured at the same time using three sensors of a slab displacement measurement sensor, a roll displacement measurement sensor, and a frame displacement measurement sensor. A method using an arithmetic expression that subtracts one value and converts it to true inter-roll bulging.

In the method (1), since the deflection, deformation and gap of the frame, roll and bearing cannot be clearly determined (because the displacement including mechanical play is detected), the bulging amount between the rolls can be accurately detected. Can not. On the other hand, in the method of the present invention, as shown in FIG. 2, in order to correct the displacement of the slab upper surface by detecting the displacement of the frame, the roll, and the bearing, the actual amount of bulging between the rolls from the lower surface of the roll is calculated. The bulging amount between the rolls can be accurately measured.

(3) Excessive bulging determination / monitoring standard A correlation diagram serving as a criterion based on a relational expression representing the relationship between the amount of bulging between rolls, casting speed Vc, slab width W or steel type (slab carbon amount C). When the bulging amount between the rolls exceeding the correlation diagram is detected, the operator is notified by a screen display and an alarm, and a measure that leads to an increase in the specific water amount such as a reduction in casting speed for reducing the bulging between the rolls is urged. . It goes without saying that the casting speed and the like can be automatically adjusted based on the respective criteria for the casting speed Vc, the slab width W, and the slab carbon amount C.

Next, examples of the criteria will be described. As one of the backgrounds of the determination method, there is a formula for calculating the maximum deflection in a state in which a uniformly distributed load is applied to a four-sided restrained flat plate by a roll that restrains both sides of the solidified short side in material mechanics. The general formula for the maximum deflection Dmax is shown below.

[0029]

(Equation 2)

Equation (2) shows that the constraint length L and the slab solidification shell thickness t are the controlling factors of the deflection D (bulging between rolls). Generally, L and P are invariable factors determined by equipment factors. Therefore, these elements (L, P)
Is determined, it can be organized by the sheet thickness term of (E × t ³ ) and W, and the maximum bending calculation formula can be calculated relatively easily and put together.

On the other hand, the controlling factor of the bulging amount between the rolls is generally the thickness of the solidified slab shell at that time, and the solidified shell is determined by the solidification coefficient k by spray water, the machine length Lm, and the casting speed Vc. The slab solidified shell thickness t is expressed by the following equation. Among the elements, the machine length Lm and the solidification coefficient k by spray water are equipment factors and are often specified values.

[0032]

(Equation 3)

Therefore, in order to evaluate the bulging amount based on the solidified shell thickness t of the slab, the bulging amount was arranged by W / Vc ² . 3 (a) shows the result of organizing bulging amount W / Vc ^2, FIG. 3 (b) is the result of organizing bulging amount of carbon content. Note that this is for a roll pitch of 500 mm. The following criterion equation is obtained from the linear approximation of FIG.

[0034]

(Equation 4)

That is, the upper limit value of the converted waveform result arranged according to each element and basis is the upper limit of the allowable bulging amount between the rolls which normally occurs, and is the alarm set value of the present invention.

When the arithmetic processing is performed using the above-described apparatus and reference, and even one of the bulging amounts between the rolls accurately measured as described above exceeds the alarm value (excessive displacement),
It is determined that the displacement is excessive displacement (excess bulging).

FIG. 4 shows an actual sensor output waveform, which is very difficult to judge in a continuous measurement. However, the present invention has a judgment criterion, and thus has a complicated It can be easily determined whether the continuous curve exceeds the two criteria and whether the numerical value exceeding the two criteria is instantaneous or continuous. In the conventional method, even if the waveform can be detected as shown in FIG.
Since it could not be converted into a numerical value that is easy to judge, it was difficult to judge the bulging, specify the displacement (differentiate from other displacements), and quantify it.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. This is an example in which the present invention is applied to a pinch roll band for continuous casting of a slab. FIG. 6 shows an example of detection of inter-roll bulging in the pinch roll band of the present invention. FIG. 7 shows a sensor base for measuring the displacement of the upper surface of the slab used in the present invention. FIG. 8 is a flowchart showing an example of the operation procedure of the present invention.

In FIG. 6, a pinch roll band 10 is formed on the downstream side of the continuous casting facility, and the slab S coming out of the pinch roll band 10 is run and cut by a torch cart 11 on a torch lower table 12. It becomes a slab of a predetermined length. The pinch roll band 10 has a large number of segments 13.
Each segment 13 includes an upper frame 15 provided with an upper roll 14 and a lower frame 17 provided with a lower roll 16. The upper frame 15 is supported by guide posts so as to be vertically movable with respect to the fixed lower frame 17, and is fixed by a clamp cylinder or the like.

In such a pinch roll band 10,
The laser sensor 1 as a non-contact high-resolution distance sensor is provided in an arbitrary segment 13. This laser sensor 1 includes a red semiconductor laser (wavelength 500 to 80).
0 nm, output class 3B), and true inter-roll bulging using three sensors: a sensor 1a for measuring the displacement of the upper surface of the slab, a sensor 1b for measuring the upper surface displacement of the roll, and a sensor 1c for measuring the frame displacement. Measure the amount δ ^* .

As shown in FIGS. 6B and 6C, the sensor 1a for measuring the displacement of the slab upper surface measures the upper surface of the slab at the center between the rolls of adjacent segments and at the center in the slab width direction. It is mounted on the upper frame 15 via the sensor base 2 so that it can be performed. The sensor mount 2 is provided at a location where the upper frame 15 does not undergo frame displacement due to static iron pressure, for example, a portion for connecting and fixing the upper frame 15 and the lower frame 17, that is, an end in the casting direction and the slab width direction of the upper frame 15. Installed in the department.

As shown in FIG. 7, the sensor mount 2 includes a vertical mount (existing) 18 fixed on the segment 13 and a horizontal mount detachably fixed to the mount 18 with bolts and nuts. 19, a slider 22 guided by a guide 20 and horizontally moved by a screw rod 21, and a support member 23 for mounting the sensor 1a to the slider 22 in a cantilever manner. The position of the sensor head can be adjusted and the sensor can be relocated. And

Also, an oxide scale adhering to the slab surface
In order to prevent erroneous detection due to spray cooling water, FIG.
As shown in (b) and (c), a gas blow nozzle 24 is installed to blow a gas such as N _{2 to the} measurement position of the slab upper surface. This gas blow nozzle 24 is disposed at the center between the rolls of the adjacent segments, similarly to the sensor 1a for measuring the displacement of the slab upper surface, but in the slab width direction, from the center in the slab width direction to one side. By displacing and bending the front end portion and directing it toward the center portion, the measurement of the sensor 1a is not hindered.

The sensor 1b for measuring the roll upper surface displacement is
It is installed on the upper frame 15 so that the displacement of the upper surface of the upper roll 14 close to the measurement position on the upper surface of the slab can be measured. The frame displacement measuring sensor 1c is fixed to an appropriate position independent of the segment 13 so that the displacement of the upper frame 15 to which the upper roll 14 to be measured is attached can be measured.

The preparation of the sensor 1a for measuring the displacement of the slab upper surface is performed in the procedure shown in FIG. 8 (a). When the sensor base 2 is installed and the position adjustment of the sensor head of the sensor 1a is completed, the zero point adjustment of the sensor 1a is performed using a T-shaped jig 25 as shown in FIG. The measurement signals from the laser sensors 1a, 1b, 1c are input to the personal computer 4 via the amplifier box 3, as shown in FIG.

Personal computer 4 (with PC card slot)
In the above, the calculation of the above equation (1) is performed to obtain the actual inter-roll bulging amount δ ^* from the lower surface of the actual upper roll 14 shown in FIG. In addition, in the personal computer 4, judgment criteria based on equations (4) and (5) obtained in advance are registered, and if the inter-roll bulging amount δ ^{* of} the measurement result exceeds the judgment criterion, excessive bulging occurs. Judge and notify the operator by alarm and screen display. If the bulging amount between rolls δ ^* does not exceed the criterion, the current condition is maintained.If the bulging amount exceeds the criterion, the operator takes measures to increase the specific water amount, such as reducing the casting speed and increasing the spray cooling water amount. Or automatically (see FIG. 1 (b)). Fig. 8 (b)
Shows the procedure for measurement.

When the roll pitch is different from that of the above embodiment, the coefficient A (W
/ Coefficients obtained from L) and a roll pitch L ⁴ can be used in terms of each equation.

The criterion for determination is not limited to the relational expression between the bulging amount and (slab width / square of casting speed) in the above-mentioned expression (4). The relational expression between the bulging amount between rolls and the casting speed Vc, A relational expression between the bulging amount and the slab width W may be used.

The detection, determination and prevention of bulging in the pinch roll band have been described above, but the present invention is not limited to this, and the present invention is also applied to the detection, determination and prevention of bulging in the upstream guide roll group. be able to.

[0050]

As described above, the present invention has the following advantages.

(1) Using a non-contact high-resolution sensor such as a laser, the top displacement of the slab, the top displacement of the roll, and the displacement of the frame are measured, and the displacement of the top surface of the roll and the displacement of the frame are subtracted from the top displacement of the slab. Since the inter-roll bulging is determined, mechanical play such as roll bending / bending, bearing gap, frame hydraulic displacement / mechanical gap can be offset, and minute bulging between rolls can be accurately detected. .

(2) By comparing the measured accurate inter-roll bulging amount with a judgment criterion based on a relational expression between the previously determined bulging amount and the slab width, casting speed, and slab carbon amount, Since bulging is determined, dangerous bulging can be detected early and easily and accurately.

(3) Dangerous bulging is detected at an early stage, and the casting conditions are changed to suppress the bulging amount.
Breakage of the equipment after the pinch roll band can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 (a) is a schematic side view of equipment showing a bulging detection method of the present invention, and FIG. 1 (b) is a block diagram for implementing a bulging determination monitoring method of the present invention.

2A is a side view and FIG. 2B is a cross-sectional view showing a detection state according to the bulging detection method of the present invention.

FIG. 3 is a graph showing an example of a judgment criterion of the bulging judgment monitoring method of the present invention.

FIG. 4 is a graph showing a sensor output waveform and determination criteria according to the present invention.

FIG. 5 is a graph showing a waveform of a conventional displacement.

FIG. 6 is an embodiment of the present invention, wherein (a) is a side view of a pinch roll band of a continuous casting facility, and (b) and (c) are side views and cross sectional views of a segment portion of the pinch roll. is there.

7A is a plan view, FIG. 7B is a front view, and FIG. 7C is a cross-sectional view showing a sensor mount used in the present invention.

FIGS. 8A and 8B are operation flowcharts of the present invention, wherein FIG. 8A shows preparations and FIG. 8B shows a procedure at the time of measurement.

[Explanation of symbols]

 S: slab (slab) 1: non-contact high-resolution sensor (laser sensor) 1a: slab upper surface displacement measuring sensor 1b: roll upper surface displacement measuring sensor 1c: frame displacement measuring sensor 2: sensor pedestal 3. amplifier Box 4 ... PC 10 ... Pinch roll strip 11 ... Torch cart 12 ... Torch lower table 13 ... Segment 14 ... Upper roll 15 ... Upper frame 16 ... Lower roll 17 ... Lower frame 18 ... Vertical mount 19 ... Horizontal mount 20 ... Guide 21 ... Screw rod 22 ... Slider 23 ... Support member 24 ... Gas blow nozzle 25 ... T-shaped jig

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yukio Narige, 3rd, Ojiko, Kashima City, Ibaraki Prefecture Sumitomo Metal Industries, Ltd. Kashima Works (72) Inventor, Masamitsu Minato 3rd, Ojiko, Kashima City, Ibaraki Prefecture, Sumitomo Metal Industries (56) References JP-A-61-67550 (JP, A) JP-A-6-328213 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 11 / 16

Claims (6)

(57) [Claims] 1. A method for detecting bulging between slab rolls of a slab in a continuous casting facility, wherein a non-contact type distance sensor is used to displace a slab upper surface between the rolls with respect to a frame, and to determine a roll approaching the slab upper surface. For the top frame
The displacement and the frame of this roll frame is independent
Measuring the displacement with respect to the fixed member , and subtracting the measured value of the displacement of the upper surface of the roll and the measured value of the displacement of the frame from the measured value of the displacement of the slab upper surface to obtain a true inter-roll bulging amount. Bulging detection method. 2. A method for determining bulging between slab rolls of a slab in a continuous casting facility, wherein a non-contact type distance sensor is used to displace a slab upper surface between rolls with respect to a frame , and to determine a roll approaching the slab upper surface. For the top frame
The displacement and the frame of this roll frame is independent
Measure the displacement with respect to the fixed member , and subtract the measured value of the displacement of the upper surface of the roll and the measured value of the displacement of the frame from the measured value of the displacement of the slab upper surface to obtain a true inter-roll bulging amount,
When the bulging amount between the rolls exceeds any one of the determination criteria calculated by the relational expression representing the relationship between the bulging amount between the rolls and the slab width, the casting speed, or the slab carbon amount, which is determined in advance. And a method for determining bulging of a continuous cast slab, which is determined to be dangerous bulging. 3. A method for preventing bulging between slab rolls of a slab in a continuous casting facility, wherein a non-contact type distance sensor is used to displace a slab upper surface between the rolls with respect to a frame and a roll approaching the slab upper surface. For the top frame
The displacement and the frame of this roll frame is independent
Measure the displacement with respect to the fixed member , and subtract the measured value of the displacement of the upper surface of the roll and the measured value of the displacement of the frame from the measured value of the displacement of the slab upper surface to obtain a true inter-roll bulging amount,
When the bulging amount between the rolls exceeds any one of the determination criteria calculated by the relational expression representing the relationship between the bulging amount between the rolls and the slab width, the casting speed, or the slab carbon amount, which is determined in advance. , Determined to be dangerous bulging,
Bulging method for preventing continuous casting slab, characterized in that to suppress the bulging ring volume by changing the casting conditions. 4. An apparatus for detecting bulging between slab rolls of a slab in a continuous casting facility, comprising:
A non-contact distance sensor for measuring the displacement with respect to the frame, the frame of the roll top adjacent to the slab top surface
A non-contact distance sensor for measuring the displacement against, against the fixing member that is independent of the frame of the frame of the roll
A non-contact type distance sensor that measures the displacement of the slab, a device that blows the measuring point on the slab surface with gas, and subtracts the measured value of the roll upper surface and the measured frame displacement from the measured value of the slab upper surface. A bulging detecting device for a continuous cast slab, comprising an arithmetic processing device for calculating a true inter-roll bulging amount. 5. An apparatus for determining bulging between slab rolls of a slab in a continuous casting facility, comprising:
A non-contact distance sensor for measuring the displacement with respect to the frame, the frame of the roll top adjacent to the slab top surface
A non-contact distance sensor for measuring the displacement against, against the fixing member that is independent of the frame of the frame of the roll
A non-contact type distance sensor that measures the displacement of the slab, a device that blows gas at the measurement point on the slab, and a device that subtracts the measured value of the roll upper surface and the measured frame displacement from the measured value of the slab upper surface. The inter-roll bulging amount is determined, and the inter-roll bulging amount is determined by a relational expression representing the relationship between the previously determined inter-roll bulging amount and the slab width, casting speed or slab carbon amount. A bulging determination device for a continuous cast slab, comprising: an arithmetic processing device that determines a dangerous bulging when any one of the bulging ratios is exceeded. 6. An apparatus for preventing bulging between slabs of a slab in a continuous casting facility, comprising:
A non-contact distance sensor for measuring the displacement with respect to the frame, the frame of the roll top adjacent to the slab top surface
A non-contact distance sensor for measuring the displacement against, against the fixing member that is independent of the frame of the frame of the roll
A non-contact type distance sensor that measures the displacement of the slab, a device that blows gas at the measurement point on the slab, and a device that subtracts the measured value of the roll upper surface and the measured frame displacement from the measured value of the slab upper surface. The inter-roll bulging amount is determined, and the inter-roll bulging amount is determined by a relational expression representing the relationship between the previously determined inter-roll bulging amount and the slab width, casting speed or slab carbon amount. A bulging prevention device for a continuous cast slab, comprising: an arithmetic processing unit that determines a dangerous bulging when any one of the above conditions is exceeded, and suppresses the bulging amount by changing a casting condition.