JPS6031008A - Apparatus for measuring thickness of solidified cast piece - Google Patents

Abstract

PURPOSE:To provide an accurate apparatus which is operated safely in a severe environment, by attaching an electromagnetic ultrasonic wave generator and an electromagnetic ultrasonic wave receiver to a detector for the total thickness of a cast piece. CONSTITUTION:A pulse signal is conducted through a generating coil 3 by a pulse generator 8, and a pulse magnetic field as shown by an arrow 17 is generated. An electromotive force is induced on the surface of a cast piece 7 and an eddy current 18 is generated. A pulse electromagnetic force is generated by the mutual action with the pulse magnetic fields of the arrow 17. Ultrasonic wave vibration is generated on the surface of a cast piece 7 by said force. The electromagnetic ultrasonic wave generated on the surface of the cast piece 7 advances in the direction of an arrow 19 in the cast piece 7. When the wave reaches the other surface, vibration is generated on the surface of the cast piece 7. An electromotive force is generated on the surface of the cast piece 7 by the mutual action of the vibration and the magnetic field, which is generated by an exciting coil 5 excited by an exciting power source 9. Said electromotive force is amplified by an amplifier 10. A part required on the time axis is taken by a gate circuit 11 and sent to a transmitted-time measuring circuit 12. The thickness of the cast piece 7 is measured based on the time difference between the input signal from the gate circuit and the pulse output timing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus (hereinafter referred to as a shell thickness gauge) for measuring the stiffness thickness of a slab during continuous casting using electromagnetic ultrasonic waves.

A conventional device of this type is shown in FIG. In the figure, (1) is an electromagnetic ultrasonic generator, (2) is an electromagnetic ultrasonic receiver, (7) is a slab, and (8) is a pulse generation circuit.

(9) is the excitation power supply, (II is the amplifier, aυ is the gate circuit, 0 is the transmission time measurement circuit, C31 is the surface thermometer, (
I4 is a slab total thickness measuring device (1 piece solidification thickness calculation circuit 9
The ring is the output circuit. On the other hand, FIG. 2 is a diagram showing the principle of electromagnetic ultrasonic generation and reception in this shell thickness gauge. In this figure, (3) is an electromagnetic ultrasonic generation coil,
(4) is an electromagnetic ultrasonic detection coil, (5) is an excitation coil for generating the entire magnetic field, and (6) is a magnetic core for forming a magnetic circuit. Here, the output 0υ of the detection coil (4) is connected to the amplifier fin).

Next, the operation will be explained. The generating coil (3), which is fully energized by the pulse signal by the pulse generating circuit (8), generates a pulsed magnetic field in the direction of the arrow αη around the coil, and this pulsed magnetic field is applied to the slab of thickness D according to Lenz's law. An electromotive force is induced on the surface of (7) to generate an eddy current of 0υ. This eddy current A frame further generates a pulsed electromagnetic force due to interaction with the pulsed magnetic field indicated by the arrow (I7) according to Fleming's left-hand rule, which causes ultrasonic vibrations on the surface of the slab (7). The above is the principle of electromagnetic ultrasound generation. Next, the electromagnetic ultrasonic waves generated on the surface of the slab (7) travel inside the slab (7) in the direction of arrow 0, and when they reach the other surface, they generate vibrations on the surface of the slab (7). An electromotive force is generated on the surface of the slab (7) due to the interaction between this vibration and the magnetic field created by the excitation coil (5) excited by the excitation power source (9). This is due to Fleming's right-hand rule. This electromotive force generates an eddy current on the surface of the slab (7), and the magnetic field created by this eddy current is based on Lenz's law, and the detection coil (4)
This electromotive force signal is amplified by an amplifier as a received signal, and a necessary portion on the time axis is extracted by a gate circuit (old) and sent to the transmission time measurement circuit α. In this gate circuit QB, a time gate is normally created based on the pulse output timing signal of the pulse generating circuit. Next, in the transmission time measurement circuit, the time t required for the ultrasonic wave to propagate from the - side of the slab (7) to the other side of the back side is calculated from the time difference between the reception signal input from the gate circuit I and the pulse output timing signal. =6, and the result is sent to the coagulation thickness calculation circuit a.

Now, suppose that there is an unsolidified part left in the slab.

If the thickness of the already solidified part is 'fcd = 61 + d2, the thickness of the unsolidified part should be D-6, so the speed at which the ultrasound propagates through the solidified part is V, and the ultrasonic wave travels through the unsolidified part. If the propagation speed is 6, then the transmission time t for the ultrasonic wave to pass through the entire slab is given by dD-d. In general, V is calculated from the temperature dependence characteristic of side sound wave propagation velocity using the solidification temperature of the slab determined by the steel type and the average temperature of the solidified part determined by an average or weighted average from the surface temperature measured by a surface thermometer fi3). Furthermore, since the unsolidified portion is considered to be in a supercooled state, a value determined experimentally for the ultrasonic propagation velocity in this state is used. Therefore, as inputs to the solidification thickness calculation circuit H, in addition to the transmission time, the thickness information from the total thickness measuring device θ→, the surface temperature information from the surface thermometer U, and the solidification temperature value of the slab determined by the steel type are input. If the ultrasonic propagation velocity (6) of the unsolidified portion is determined, the solidified thickness d can be calculated from the above relational expression. The calculated solidification thickness d is displayed or recorded by the output circuit 061.

Now, in the conventional shell thickness gauge configured as described above, a slab total thickness measuring device (+=0 as shown in Fig. 3 is usually used. In the figure, (22a) (22
b) is a roller to imitate slab (7), (23a) (2
3b) is a support rod for this roller, and (24a) and (24b) are length gauges for measuring the vertical stroke amount of the support rod.

(25a) (25b) are actuators for raising and lowering the support rods (25a) (23b), (26a) (26
b) is a storage box for storing length meters, etc. (27a) (27b
) is a trolley for traversing.

(28a) and (28b) are rails for the bogie to traverse.

Figure 3(a) shows the support rod (23) used to measure the total thickness D.
Figure 3(b) is a diagram showing the support rod (23a)'i raised and the support rod (23b) lowered when no measurement is being performed. are doing.

Figure 3 (b) D when no measurement is performed as shown in K
C+ When the distance from the lower end of (22a) to the upper end of roller (22b) is C4, from the state of Fig. 3(b) to the third
The stroke amounts a and bl of the support rod (25a) and support rod (23b) until the state shown in figure (a) is reached are measured using a length meter (24a).
) and (24b) 1 , the thickness D of the slab (7) can be calculated using the following formula.

Dcoc (a, +b,) Now, in order to measure the thickness of the slab (7) as described above, C4 must be known, but normally this C1
Measure a calibration block whose thickness is known in advance on the edge of the slab (7), and then measure the support rod (23a) (
2Sb) Stroke 'ta2sb2 Also, if the calibration block thickness is S, it can be calculated using the quadratic formula % formula %.

The above is the operating principle of the slab total thickness measuring device (14).

However, the total slab thickness measuring device 04 of the shell thickness gauge constructed as described above had the following drawbacks.

(1) Since the position where the ultrasonic transmission time t was measured and the position where the total slab thickness D was measured are different, the difference in the position of the total slab thickness D directly affects the measurement error of the slab solidification thickness d. do.

(2) Since the support rods (23a) and (23b) expand and change their lengths due to radiant heat from the slab or ambient temperature, an error occurs in the measured value of the total thickness D of the slab.

(3) Since the slab (7) is generally in a high temperature state of around 1000°C, a cooling mechanism is usually required. However, when an emergency situation such as an abnormality in the cooling mechanism occurs, the roller (22a)
22b) It is necessary to evacuate the parts of the slab exposed to high heat to a safe location, but the supply of power sources such as electricity, compressed air (hereinafter referred to as air), or hydraulic pressure necessary for evacuation is cut off at the same time. When it is stored away, this evacuation function does not work and there is a risk of burning out the parts exposed to high heat.

(4) In order to reduce the influence of radiant heat from the slab, if you try to move the body of the slab total thickness measuring device α4 as far away from the slab as possible, it is necessary to lengthen the stroke length of the support rod. For the reason stated in 2), the measurement error of the total thickness D of the slab increases, making it difficult to simultaneously reduce the influence of radiant heat and shorten the stroke length.

(5) Support rods (23a) (23b) when not measuring
Because it protrudes rearward by the length of the stroke, a space is required on the opposite side of the bogie from the slab (7), and in particular, for the lower transverse bogie (27b), there are pits on the floor as shown in Figure 3. There are cases where it is necessary to investigate.

This invention eliminates these drawbacks of the total slab thickness measuring device I of the shell thickness gauge, reduces the measurement error of the total slab thickness D, and improves the reliability of the total slab thickness measuring device 0→. This was done to provide a shell thickness gauge with high accuracy, long life, and high safety.

FIG. 4 is a diagram showing an embodiment of the present invention.

In the figure, (29a) and (29b) are sensor heads.

(23a) (25b) are support rods, (32a) (32b)
) is a measuring rod, (24a) and (24b) are length meters,
(25a) (25b) are actuators, (26a
) (26b) is a storage box.

(30a) (30b) are storage box lifting and lowering mechanisms; (27a)
) (27b) is a traverse truck, (28a) (28b) are rails. An electromagnetic ultrasonic generator (1) is built into one side of the sensor head (29a) (29b), and an electromagnetic ultrasonic receiver (2) is built into the other side. Support rod (23a
) (23b) contains a measuring rod (
32a) (32b) are housed there and protect them. The support rods (23a) (23b) are connected to actuators (25a) (25b) and are moved up and down by the wrinkle actuators (25a) (25b). The measuring rod (32a) housed within the support rod
) (32b) are connected to the length gauges (24a) (24b)), and the length gauges (24a) (24b) are connected to the support rod (23a).
) (23b) can be measured. The storage boxes (24a) and (26b) are boxes for storing the above-mentioned actuators, length meters, cables, piping, etc.

This storage box (2/1a) (26b) is an elevator! (30
a) (lb) ' Traverse trolley (27a) (27
b)), the transverse truck (27a) (27
b) is designed to run horizontally on rails (28a) and (28b) that are passed at right angles to the direction of conveyance of the slab (7).

Figure 4(a) shows the upper transverse truck (hereinafter referred to as the upper truck) (2
The storage box (26a) on the side 7a) is at the lowest position (lower limit) by the lifting mechanism (30a), and the support rod (23a) is lowered by the actuator (25a) and the sensor head (29a) is placed in the slab. Close to (7).

In addition, the storage box (2/ib) on the lower transverse trolley (hereinafter referred to as the lower trolley) (27b) is at the highest position (ascent limit) by the lifting mechanism (3ob), and the support rod (23
FIG. 7b also shows a state in which the sensor head (29b) is raised by the actuator (25b) and is in contact with the slab (7). On the other hand, Fig. 4(b) shows the upper truck (27a
) side storage box (26a) is raised to the upper limit by the lifting mechanism (30a), and the support rod (23a) is raised to the upper limit by the actuator (25a). The storage box (26b) has a lifting mechanism (3o
b) is lowered to the lower limit by the support rod (23b).
FIG. 3 is a diagram showing a state in which the actuator (25b) has lowered the lower limit to the lower limit.

Also, in Figure 1, the storage box (26a) on the upper truck (27a) side
An emergency evacuation mechanism 01) is housed in, and FIG. 5 is a diagram showing this configuration. In the figure, (to) is a nail,
C34 is the spring that pulls the claw (to), *i is the air pressure storage tank, (to) is the pressure switch, G7) is the pressure gauge,
(to) is the solenoid valve for lifting, C1l is the solenoid valve for emergency evacuation,
(41 is an actuator for unlocking.

Next, the operation of an embodiment of the present invention shown in FIGS. 4 and 5 will be described. Figure 4 (when not measuring)
Prior to measurement, the slab total thickness measuring device, which was in the state shown in b), first turned on the lifting mechanism (30) on the upper truck (27a) side.
a) and move the lifting mechanism (30b) on the lower truck (27b) side, lower the storage box (25a) on the upper truck (27a) side,
The storage box (26b) on the lower truck (27b) side is raised.

In this embodiment, a screw jack is used as the elevating mechanism (30a) (30b), but other elevating mechanisms may of course be used. Next, in this state, prior to measurement, a calibration block of known thickness is used instead of the slab (7), and the sensor head (29a) on the upper carriage (27a) side is
The lower end of the sensor head (29b) and the lower truck (27b) side
) Measure the distance C2 between the top edge of the This operation is performed by the actuator (25a) in the same way as the conventional slab total thickness measuring device.
(25b) is used to lower or raise the support rods (23a) and (23b). However, the difference from the conventional one is that the storage box (26a) is
) (26b) is brought closer to the slab (7), the support rod (
23a) The stroke length of (25b) can be shortened,
Accordingly, errors due to thermal expansion and the like are reduced. In this embodiment, the elevating mechanism (30a) (30b) and the actuator (25a) (25b) are used for elevating in two stages, but this may be configured in three or more stages.

Now, when 02 is known by the above measurement, it becomes possible to measure the thickness D of the slab (7). Figure 4 (,) shows the support rod (25a) and (25b)
23a) (23b) f FIGS. 23A and 23B are diagrams showing a state in which the sensor head (29a) (29b) is brought into contact with the slab (7) by being lowered or raised to perform measurement. What is different from the conventional method in this state is that the sensor head (29a) (29b) has a built-in electromagnetic ultrasonic generator (1) and an electromagnetic ultrasonic receiver (2), so it can measure the thickness of the slab (7). Ultrasonic waves can be generated and detected at the same position, and the ultrasonic transmission time can be measured. Furthermore, there is another point that is different from the conventional one: the length gauges (24a) (24b) for measuring the stroke length of the dotted support rods (2Sa) (23b) are not directly connected to the support rods (23a) (23b).

It is built into a support rod that has a hollow structure. Measuring rod (32a) (3) designed to reduce thermal expansion
2b).

In this embodiment, Super Invar, which is a metal material with a very small coefficient of thermal expansion, is used as the material for the measuring rods (52a) (32b), and the supporting rods (23a) (23
b) Circulate temperature-controlled air inside the measuring rod (
The temperature environment of 32a) and 32b was kept constant. With this structure, the support rod (23a)
(23b) may cause thermal expansion due to the radiant heat of the slab (7) or the ambient temperature, or the actuator (25a) (25
Even if the measuring rod (52-) (32b) is deflected by the pressing force in b), it does not affect the measuring rod (52-) (32b), making it possible to measure the stroke length with high accuracy. In this embodiment, a super inverter is used as the material with a small coefficient of thermal expansion, but it is also possible to use other materials such as CFRP (carbon fiber laminated material). Moreover, the pressing force of the actuators (25a) (25b) is not directly applied to the measuring rods (32a) (32b), and
Since it is protected by the support rods (23a) and (23b), it is possible to use materials with low strength or poor environmental resistance. Now, - When the measurement shown in the figure is completed, the support rod (23a)
(23b) Either raise or lower the i-actuators (25a) and (25b) and wait for the second measurement point to come after the slab (7) is conveyed in the retracted state, or use the rail (28a) First measurement is performed by moving the upper truck (27a) and lower truck (27b) across (28b) to another measurement position.

Now, in such a case, the sensor head (29a) (29b
) is used in a state where it is in contact with a hot slab for a long time, so it is essential to take heat-resistant measures for the shear sensor head (29a) (29b). For this reason, some form of cooling mechanism is required, but in this embodiment, the inside of the sensor head (29a) (29b) is filled with cooling water, and a part of the cooling water is used as a cooling mechanism for the sensor head (29a) (29b). It also leaks to the surface facing (7).

However, if this cooling water is not supplied due to a water outage or a blockage on the piping, the cooling effect will be lost, and if measurements are continued in this state, there is a risk of burnout of the sensor heads (29a) (29b). It's coming.

For this purpose, for example, a water flow meter or a water pressure gauge may be installed in the cooling water supply line to detect when the cooling water supply falls below a predetermined meter and actuate the actuator (25a) (
25b) and in some cases, the lifting mechanism (30a) (30b
) to move the support rods (23a) and (23b) to the slab (7).
It is conceivable to provide a control circuit to keep it away from the ground. However, if the cause of the cooling water supply being cut off was a pump stoppage due to a power outage, etc., it would be sufficient to stop not only the electricity supply, but also the air and hydraulic pumps and the air and hydraulic supply. It can be considered. In other words, in an emergency when cooling water is not supplied, the support rod can be replaced with a slab (
7) There is no guarantee that a power source will be available to move the vehicle away from the vehicle. Therefore, in this embodiment, the actuator (25a)
Electricity is generated by using an air cylinder as (25b) and constructing an air system as shown in Fig. 5.

The support rods (25a) (23b) are kept away from the slab (7) even when the supply of water or air is stopped in any combination.

Next, this mechanism will be explained in detail. In Fig. 5, if air is supplied in the direction shown by the arrow (41), the actuator (40) will overcome the tensile force of the working spring and the claw (
) is pulled downward to release the lock.

In this example, an air cylinder was used as the actuator (41).Furthermore, if air is normally supplied, the pressure storage tank will have enough air stored to raise the actuator (25a) to zero, and the pressure switch (to)
outputs a normal air pressure signal indicating that the air pressure is sufficient. A control circuit (not shown) that inputs this signal energizes the emergency evacuation solenoid valve C1l, and in order to block the outlet of the pressure storage tank (to), a check valve (42) prevents backflow to the inlet side. Air is stored in the pressure storage tank (to) and it is in a sealed state.

In addition, the exhaust side circuit of the emergency evacuation solenoid valve (to) is connected to the check valve (4).
3), so in this state, the presence of the emergency evacuation solenoid valve C31 and the pressure accumulator tank (2) is due to the actuator (2) operated by the lifting solenoid (2).
This is equivalent to simply connecting the lifting solenoid valve (to) and the actuator (25a) directly without any influence on the operation of step 5a). Therefore, if the lifting solenoid valve is energized, the support rod (2+a) will be lowered by the actuator (25a), and conversely, if it is de-energized, the support rod (23a) will be raised by the actuator (25a). . This is the operation when there is no abnormality. Now, when the pressure switch or water flow detector installed in the cooling water supply path detects that the cooling water supply has stopped, and that signal is input to the control circuit, the control circuit controls the lifting solenoid valve. (to) is de-energized, the support rod (23a) can be raised.

At this time, if for some reason the air indicated by the arrow (41) is no longer supplied, the lifting solenoid valve (
Although it is not possible to move the actuator (25a) through (to), in this case the pressure switch (to) detects the decrease in air pressure and outputs this signal to the control circuit, so if this signal is input to the control circuit, Solenoid valve for lifting 0! O
And the emergency evacuation solenoid valve 0I is de-energized, and the pressure storage tank 0
The air stored in the actuator (25a) can be supplied to the actuator (25a) to raise the support rod (23a). On the other hand, if the air supply stops, the actuator (41) will lose its lock release function, so the spring 0 will release the lock (c).
falls to the lock side, and the support rod (23a) once raised will remain locked and will not come down until new air is supplied next time.

On the contrary, air is being supplied normally.

When the electricity supply is cut off for some unknown reason.

Since both the elevating solenoid valve (2) and the emergency evacuation solenoid valve C1l are de-energized, the air supplied through them both acts on the actuator (25a) to raise the support rod. In addition, when the air supply and electricity supply are cut off, the lift solenoid valve (to) and the emergency evacuation solenoid valve 0I are de-energized without waiting for the signal from the pressure switch (to), so that no electricity is removed from the pressure storage tank. The supplied air acts on the actuator (25a) to raise the support rod (23a) f. As described above, even if the supply of cooling water, air, or electricity stops, the support rod (23a) is raised and the sensor head (29a
) is kept away from the slab (7), and the operation when the cooling water supply is stopped is exactly the same as the operation when the electricity supply is stopped. From the above explanation, the cooling water, air,
It is easy to understand that no matter what combination of electricity supply interruptions occurs, the sensor head (29a) moves away from the slab (7). In this embodiment, air cylinders are used as the actuator (25a) and the lock release actuator (41), but even if these are actuators that use other power sources such as electricity or hydraulic pressure, the gist of the present invention will still apply. Needless to say, this is not a loss. There are various other configurations that achieve the same function, and the simplified configuration shown in FIG. 6 is one example.

In addition, in the present invention, the emergency evacuation mechanism shown in 9 and above is installed only on the upper truck (27a,) side, but this is not installed on the lower truck (27b).
This is because the supporting rod (23b) on the ) side naturally falls under its own weight when the supply of air and electricity is stopped, so there is no need to provide a special evacuation mechanism (23). It goes without saying that depending on the direction in which the slab total thickness measuring device is installed, it may also be necessary to install it on the lower truck (27b) side.

Since the present invention is constructed as described above, the drawbacks of the conventional slab total thickness measuring device described above are solved.

It is possible to obtain a total thickness measuring device for slabs with little error and that can operate safely even in harsh environments, and it is possible to provide a highly accurate shell thickness meter.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of a conventional shell thickness meter, Figure 2 is a diagram showing the principle of electromagnetic ultrasound generation and reception, and Figure 3 is a diagram showing the principle of electromagnetic ultrasonic generation and reception.
The figure shows the configuration of a conventional slab total thickness measuring device, Figure 4 shows the configuration of a slab total thickness measuring device according to the present invention, and Figures 5 and 6 show the configuration of an emergency evacuation mechanism. FIG. In the figure, (1) is an electromagnetic ultrasonic generator, (2) is an electromagnetic ultrasonic receiver, (7) is a slab, (8) is a pulse generation circuit, and (9) is an electromagnetic ultrasonic generator.
) is the excitation power supply, fl is the amplifier, (Iυ is the gate circuit, aa is the transmission time measurement circuit, a trench is the surface thermometer, 04 is the total slab thickness (24) measuring device, aQ is the solidification thickness calculation circuit, and aQ is the Output circuit. (23a) (23b) are support rods, (24a) (24b
) is a length meter. (25a) (25b) are actuators, (27a)
(27b) is a trolley for traversing, (28a) and (28b) are rails/l/, (29a and 29b) are sensor heads, (30a) and (30b) are lifting mechanisms, and 01) is an emergency evacuation mechanism. . In the drawings, the same or corresponding parts are designated by the same reference numerals. Agent Masuo Oiwa Figure 3 (α) Figure 3 Cb) Figure 4 ((L) Figure 4 (b) 2% Figure 5 3I15+ 6 374/ ) -f 3de 4Z 3 f +-37 〃a 3 Fu 4ρ Figure 6

Claims (5)

[Claims] (1) An electromagnetic ultrasonic generator installed on one side of the slab to be continuously cast and equipped with a coil energized with a high-frequency pulse signal to generate ultrasonic waves on the surface of the slab, and the other side of the slab. an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface to receive the ultrasonic waves; and an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface of the slab to receive the ultrasonic waves; a time measuring circuit that measures the time t required for propagation to the other surface; a total thickness measuring device that measures the total thickness D of the slab; and a time t measured by the time measuring circuit; From the measured total thickness p, the speed V at which the ultrasonic wave propagates through the solidified part of the slab having a thickness d, and the speed Vt at which the ultrasonic wave propagates through the unsolidified part of the slab having a thickness D-d, the solidified part is determined. A slab solidification thickness measuring device comprising: an arithmetic circuit for calculating thickness d. A slab solidification thickness measuring device, characterized in that the electromagnetic ultrasonic generator and the electromagnetic ultrasonic receiver are attached to the slab total thickness measuring device. (2) An electromagnetic ultrasonic generator installed on one side of the slab to be continuously rolled and equipped with a coil energized with a high-frequency pulse signal to generate ultrasonic waves on the surface of the slab; An electromagnetic ultrasonic receiver equipped with a detection coil installed on a surface to receive the ultrasonic waves, and an ultrasonic wave that strikes the slab from the timing of ultrasonic generation and detection of these ultrasonic generators and receivers. The time t required for propagation from to the other surface
a total thickness measuring circuit for measuring the total thickness D of the slab, a time t measured by the time measuring circuit, a total thickness measured by the total thickness measuring device, and a total thickness measuring device for measuring the total thickness D of the slab; The speed V at which the ultrasonic wave propagates through the solidified part of the piece with thickness d
, and an arithmetic circuit that calculates the solidified portion thickness d from the velocity Vt at which the ultrasonic wave propagates through the unsolidified portion of the slab thickness D−(l). The total thickness measuring device has a contact element that comes into contact with the slab by being driven by a plurality of contacting/separating member mechanisms, and measures the distance traveled by the contact until it comes into contact with the slab. A slab solidification thickness measuring device characterized by measuring the total thickness of a slab. (3) An electromagnetic ultrasonic generator installed on one side of the slab to be continuously cast and equipped with a coil energized with a high-frequency pulse signal to generate ultrasonic waves on the surface of the slab, and the other side of the slab. an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface to receive the ultrasonic waves; and an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface of the slab to receive the ultrasonic waves; The time t required to propagate to the other surface
a total thickness measuring circuit for measuring the total thickness D of the slab; a time t measured by the time measuring circuit; a total thickness measuring circuit for measuring the total thickness D of the slab; The speed at which ultrasonic waves propagate through the solidified part of the piece with thickness d■
, and an arithmetic circuit that calculates the thickness dk of the solidified part from the velocity wave vt in which ultrasonic waves propagate through the unsolidified part of the slab having a thickness D-tl. A contact element through which a slab total thickness measuring device comes into contact with the slab. It has a support rod that supports the contact, a measuring rod provided separately from the support rod, and a length meter connected to the measuring rod, and the contact contacts the slab. A solidification thickness measuring device for a fishing slab, characterized in that the total thickness of the slab is measured by measuring the distance traveled by the length meter. (4) An electromagnetic ultrasonic generator installed on one side of the slab to be continuously cast and equipped with a coil energized with a high-frequency pulse signal to generate ultrasonic waves on the surface of the slab, and the other side of the slab. an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface to receive the ultrasonic waves; and an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface of the slab to receive the ultrasonic waves; The time t required to propagate to the other surface
a total thickness measuring circuit for measuring the total thickness D of the slab; a time t measured by the time measuring circuit; a total thickness measuring circuit for measuring the total thickness D of the slab; The speed at which ultrasonic waves propagate through the solidified part of the piece with thickness d is fu
A slab solidification thickness measuring device comprising: v e and a calculation circuit that calculates the solidified portion thickness de from the velocity Vt at which the ultrasonic wave propagates through the unsolidified portion of the slab having a thickness D−d. a storage device for storing a power source necessary for retracting a portion of the total thickness measuring device that is close to the slab; A slab solidification thickness measuring device comprising an evacuation mechanism that extracts a power source from the storage device and evacuates a portion of the slab that is close to the slab when an abnormal condition occurs. (5) an electromagnetic ultrasonic generator installed on one side of the slab to be continuously cast and equipped with a coil energized with a high-frequency pulse signal to generate ultrasonic waves on the surface of the slab, and the other side of the slab; an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface to receive the ultrasonic waves; and an electromagnetic ultrasonic receiver equipped with a detection coil that is installed on the surface of the slab to receive the ultrasonic waves; The time t required to propagate to the other surface
a total thickness measuring circuit for measuring the total thickness D of the slab; a time t measured by the time measuring circuit; a total thickness measuring circuit for measuring the total thickness D of the slab; The speed at which ultrasonic waves propagate through the solidified part of the piece with thickness d■
, and an arithmetic circuit for calculating the solidified portion thickness d from the velocity Vt at which the ultrasonic wave propagates through the unsolidified portion of the slab thickness D−(l). a storage device for storing a power source necessary for the slab total thickness measuring device to evacuate a portion of the slab that is close to the slab; when an abnormal condition occurs, the power source is removed from the storage device and the slab is removed; A slab solidifying and thickening device comprising: a retracting mechanism for retracting a portion that is close to the slab; and a fixing mechanism that fixes a portion that is close to the retracted slab.