JP2006053040A - Cast piece freezing layer thickness measuring device of continuous casting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cast piece freezing layer thickness measuring device capable of accurately detecting a cast piece freezing layer thickness without adversely affecting to cast piece quality. <P>SOLUTION: The device consists of a contact medium supply means for a cast roll which a contact medium 16 for cast roll consisting of a low melting point material in paste state or powder state is intermittently supplied to the outer surface of a rotating cast roll 52 contacting a cast piece 51; an ultrasonic probe 11 for contacting the cast roll 52 by way of a contact medium 13; and a measuring means for calculating the cast piece freezing layer thickness on the basis of a boundary surface echo by detecting the surface echo of boundary between the freezed layer and non-freezed layer of the cast piece 51 from the difference between ultrasonic echo S2 received with the ultrasonic probe 11 in the case that the cast roll 52 and the cast piece 51 are contacting by way of the contact medium 16 for the cast roll and ultrasonic echo S1 in the case contacting without the contact medium 16 for the cast roll. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slab solidified layer thickness detecting device of a continuous casting machine that detects the solidified layer thickness of a slab by ultrasonic waves.

  As shown in FIG. 6, the continuous casting machine has a rectangular cross section mainly drawn from a molten steel poured into a mold 55 through a tundish 54 from a master pan 53 and gradually drawn downward by a casting roll 52 while being cooled from the outside. The slab 51 is manufactured. The solidified slab 51 is cut into a certain length by a gas cutting machine 56 or the like to become an intermediate product called a slab 57 or the like. In this continuous casting machine, the balance between the cooling speed and the casting speed (drawing speed) is an important factor for ensuring product quality and productivity. For example, if the drawing speed is increased too much, a hot water leakage accident may occur due to insufficient solidification of the slab, or a major accident such as a breakout directly under the mold may occur. End up. On the other hand, if the drawing speed is too slow, the productivity decreases. Therefore, it is indispensable for stable and high production operation in a continuous casting machine to appropriately detect the solidification state of the slab and to realize and maintain the optimum drawing speed and cooling state.

  Therefore, conventionally, as a slab solidified layer thickness detection device in a continuous casting machine, a device has been proposed in which the solidified layer thickness of a slab in which solidification is in progress is detected by ultrasonic waves. For example, in Japanese Patent Publication No. 60-11587, ultrasonic waves incident obliquely on the slab surface are utilized by utilizing the fact that an ultrasonic beam is refracted at the boundary surface between the solidified layer and the unsolidified layer of the slab. In this example, the thickness of the solidified layer is detected from the detection position on the surface of the slab opposite to the surface of the slab (Prior Art 1).

  Japanese Patent Publication No. 2-22882 discloses a technique in which the thickness of a solidified layer is detected by utilizing the reflection of ultrasonic waves at the boundary surface between a solidified layer and an unsolidified layer of a slab. (Prior art 2).

  By the way, when the solidified layer thickness of a slab is detected by ultrasonic waves, it is necessary to make the ultrasonic waves effectively enter the slab and to detect the ultrasonic waves propagated in the slab. A material called contact medium such as water or oil is supplied between the ultrasonic probe and the slab so as not to reduce the transmission efficiency of the ultrasonic wave between the acoustic probe and the slab to be detected. Like to do.

  As such a contact medium supply means, in the prior art 1, as shown in FIG. 7, two casting rolls 52 that are adjacent to each other along the slab drawing direction are opposed to each other with the slab 51 interposed therebetween. The water jet nozzles 62A and 62B are arranged, the incident ultrasonic probe 61A is installed in one water jet nozzle 62A, and the receiving ultrasonic probe 61B is installed in the other water jet nozzle 62B. is doing. Thereby, a water jet is sprayed toward the slab 51 to realize a local water immersion state, and ultrasonic waves are transmitted and received through the water jet. Reference numeral 51a denotes a solidified layer (solidified portion) of the slab 51, and 51b denotes an unsolidified layer (unsolidified portion) of the slab 51.

  However, in the slab solidified layer thickness detecting apparatus having the means shown in FIG. 7, since the slab to be detected is high temperature, bubbles (such as water vapor) are likely to be generated in the water jet, which may hinder ultrasonic transmission. There has been a problem that often occurs. Furthermore, since a large amount of water is sprayed on the slab, the cooling of the slab is accelerated locally, so that there is a concern that the slab quality may be adversely affected by cracking on the surface of the slab.

  As another contact medium supply means, in the prior art 1, as shown in FIG. 8, a drum 72 is rotatably supported by being brought into pressure contact with one surface of a slab 51. The cooling liquid 73 is filled, and the ultrasonic probe 71 is installed in the cooling liquid 73.

  However, in the slab solidified layer thickness detecting device having the means shown in FIG. 8, there is no contact medium between the drum 72 and the slab 51, so the contact pressure between the drum 72 and the slab 51 is increased. However, the ultrasonic transmission efficiency with respect to the slab 51 was very poor, attenuated to 1/10 or less as compared with the case where a contact medium such as water was supplied, and the sensitivity to detect the solidified layer thickness was low.

  Further, as another contact medium supply means, the above-described conventional technology 2 has a contact surface pressed against the surface of the slab 51 as shown in FIG. 9, and this contact surface is melted by the heat of the slab 51. A melting medium 82 as a contact medium made of a material having a low melting point such as copper, lead, etc., a casing 83 that holds the melting medium 82 in a detachable manner, and cools it, and a non-contact of the melting medium 82 in the casing 83 It comprises an ultrasonic probe 81 that is closely fixed to a portion (surface opposite to the contact surface). As a result, ultrasonic waves are incident on the slab 51 via the molten medium 82, and the ultrasonic echoes are received via the molten medium 82.

However, in the slab solidified layer thickness detecting device having the means shown in FIG. 9, detection is impossible when the finite length of the molten medium 82 is completely melted. Therefore, it is necessary to periodically replace the molten medium 82. There is. Further, since the length of the melting medium 82 is gradually reduced by melting, the relative distance between the ultrasonic probe 81 and the cast piece 51 changes with the progress of casting, and a truly constant ultrasonic transmission / reception state is achieved. Is impossible to maintain.
Japanese Patent Publication No. 60-11587 (FIGS. 6 and 7) JP-B-2-22882 (Fig. 6)

  Therefore, an object of the present invention is to detect a thickness of a solidified layer of a slab with an ultrasonic probe through a casting roll that is in contact with the slab in a continuous casting machine. The contact medium can be stably supplied without adversely affecting the quality of the slab, and the influence of multiple echoes due to the presence of the casting roll can be eliminated, and the boundary between the solidified layer and the unsolidified layer of the slab Provided is a slab solidified layer thickness detection device for a continuous casting machine capable of accurately detecting only a surface echo and accurately detecting a slab solidified layer thickness without adversely affecting the slab quality. There is.

  In order to solve the above problems, the present invention takes the following technical means.

  According to the first aspect of the present invention, in the slab solidified layer thickness detecting device of a continuous casting machine for detecting the solidified layer thickness of the slab by ultrasonic waves, the outer peripheral surface of the casting roll rotating in contact with the slab is pasty or A casting roll contact medium supplying means for intermittently supplying a casting roll contact medium made of a powdery low-melting substance, and substantially normal to the outer peripheral surface of the slab at the contact point between the casting roll and the slab An ultrasonic probe that is in contact with the casting roll through a contact medium, and the ultrasonic probe when the casting roll and the slab are in contact with each other through the casting roll contact medium. Difference between the ultrasonic echo received by the probe and the ultrasonic echo received by the ultrasonic probe when the casting roll and the slab are in contact with each other without the contact medium for the casting roll. The solidified layer of the slab and the unsolidified Detecting a boundary surface echo with the layer, a slab solidified layer thickness detection device of the continuous casting machine, characterized by comprising a measuring means for obtaining a cast slab solidified layer thickness, the based on the boundary surface echo.

  According to a second aspect of the present invention, in the slab solidified layer thickness detecting device of the continuous casting machine according to the first aspect, the ultrasonic probe is arranged inside the casting roll filled with cooling water. It is characterized by being.

  According to a third aspect of the present invention, in the slab solidified layer thickness detecting device of the continuous casting machine according to the first or second aspect, the low-melting-point substance is a graphite paste or a casting powder.

  The slab solidified layer thickness detecting device of the continuous casting machine according to the present invention is used to detect the solidified layer thickness of a slab with an ultrasonic probe through a casting roll that rotates in contact with the slab. A predetermined amount of a casting roll contact medium made of a low melting point material in the form of a paste or powder on the surface is intermittently supplied, and the casting roll contact medium approaches the slab as the casting roll rotates, When the point of contact with the slab is reached, the liquid is formed into a liquid by the heat generated by the contact with the high-temperature slab and is supplied as an ultrasonic contact medium between the casting roll and the slab. Therefore, a predetermined amount of contact medium can be stably and intermittently supplied between the casting roll and the slab without thermally detrimentally affecting the slab quality, thereby preventing a reduction in ultrasonic transmission efficiency. Thus, it is possible to maintain high solidified layer thickness detection sensitivity.

  In addition, an ultrasonic probe is used when the casting roll contact medium is intermittently supplied to the outer peripheral surface of the casting roll, and the casting roll and the slab are in contact with each other through the liquid casting roll contact medium. It is configured to take the difference between the ultrasonic echo received by the child and the ultrasonic echo received by the ultrasonic probe when the casting roll and the slab are in contact without the casting roll contact medium. Yes. Thereby, it is possible to accurately detect only the boundary surface echo between the solidified layer and the unsolidified layer of the slab, which is an echo from the slab, without the influence of multiple echoes caused by the presence of the casting roll, Based on the boundary surface echo, the thickness of the slab solidified layer can be obtained with high accuracy. Therefore, the thickness of the slab solidified layer can be accurately detected without adversely affecting the slab quality, and the continuous casting machine can be stabilized and contribute to an operation with high productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a configuration of a slab solidified layer thickness detecting device of a continuous casting machine according to an embodiment of the present invention.

  In FIG. 1, 51 is a slab in which solidification in a continuous casting machine is in progress, and is drawn from the top to the bottom in FIG. Reference numeral 52 denotes one of a plurality of casting rolls in contact with the slab 51 and rotates clockwise at a constant speed. A solidified layer 51a and an unsolidified layer 51b exist inside the slab 51, and it is important for operation management to detect (measure) the thickness of the solidified layer.

  The ultrasonic probe 11 is positioned substantially on the normal line with respect to the outer peripheral surface of the slab at the contact point between the casting roll 52 and the slab 51, and is cast via the probe contact medium (ultrasonic transmission medium) 13. It is arranged in contact with the roll 52. That is, in the present embodiment, the ultrasonic probe 11 is disposed via the probe contact medium 13 at a position on the outer peripheral surface of the casting roll 52 opposite to the contact point with the cast piece 51. Reference numeral 12 denotes a probe contact medium application nozzle that constantly supplies the probe contact medium 13 between the ultrasonic probe 11 and the casting roll 52. Examples of the probe contact medium 13 include water, glycerin, and the like, but water is preferable in terms of cost and a cooling effect on the casting roll 52.

The contact medium tank 14 for the casting roll is located between the ultrasonic probe 11 and the contact point between the casting roll 52 and the cast slab 51, and in the present embodiment above the top position in the vertical direction of the outer peripheral surface of the casting roll 52. A casting roll contact medium coating nozzle 15 is disposed for intermittently applying a predetermined amount of the casting roll contact medium 16 to the outer peripheral surface of the casting roll 52. In addition, with respect to the longitudinal direction of the casting roll 52, the ultrasonic probe 11 and the casting roll contact medium application nozzle 15 are arranged at the same position. The contact medium 16 for casting rolls is paste-form or powder-form (solid) at normal temperature, and is in a liquid state without vaporizing and evaporating by contacting the slab 51 having a surface temperature of about 900 to 1200 ° C. The melting point material is preferably a graphite paste or a casting powder. It should be noted that even if it is not a single substance, it may be in a liquid state without being evaporated and evaporated as a mixed state. As casting powder (molding powder for casting), generally, CaO, SiO ₂ , Al ₂ O ₃ or the like as a base material and an alkali metal or the like added thereto are used. The casting roll contact medium 16 applied to the outer peripheral surface of the casting roll 52 by the casting roll contact medium application nozzle 15 approaches the slab 51 with the rotation of the casting roll 52, and is formed between the casting roll 52 and the slab 51. When the contact point is reached, it becomes liquid by heat due to contact with the hot slab and is supplied as an ultrasonic contact medium (ultrasonic transmission medium) between the casting roll 52 and the slab 51. Yes. Then, the casting roll contact medium 16 remaining after passing through the contact point with the slab 51 is removed by the contact medium removing mechanism 17.

  The casting roll contact medium application nozzle 15 has a truncated inverted conical cylindrical shape at the bottom of the nozzle, and the pouring spout of the casting roll contact medium 16 is wide and the supply port to the casting roll 52 is narrow. . In the present embodiment, a small screw feeder is installed in the casting roll contact medium tank 14, and a predetermined predetermined amount of the casting roll contact medium 16 is rotated by a motor. Is applied to the outer peripheral surface of the casting roll 52 from the contact medium coating nozzle 15 for casting roll.

  Reference numeral 18 denotes a rotary encoder (rotation detector) that is attached to the roll shaft of the casting roll 52 and knows the rotation angle of the casting roll 52 from a predetermined set point. Reference numeral 24 denotes a counter for counting the number of rectangular wave output signals of the rotary encoder 18. The rotary encoder 18 and the counter 24 are for determining the application timing of the casting roll contact medium 16 and for determining the reading timing of the ultrasonic echo received by the ultrasonic probe 11.

  Reference numeral 20 denotes a pulsar. The ultrasonic probe 11 generates an ultrasonic wave when a pulse voltage generated from the pulsar 20 is applied, and the ultrasonic probe 11 is directed toward the contact point between the casting roll 52 and the cast piece 51. Send a pulse. The receiver 21 receives the ultrasonic echo returned to the ultrasonic probe 11 and converts it into a pulse voltage. Reference numeral 23 denotes an arithmetic processing unit composed of a programmed microcomputer. The arithmetic processing unit 23 receives the count value of the counter 24 (the rotation angle of the casting roll 52) as an input, and the ultrasonic echoes S1 and S2 received by the ultrasonic probe 11 (receiver 21) are A / The slab solidified layer thickness d, which is input via the D converter 22 and output, is output to the display unit 25 and output to an external control system as necessary. Further, the arithmetic processing unit 23 outputs a casting roll contact medium application command for driving a motor that rotates the screw feeder in the casting roll contact medium tank 14.

  The casting roll contact medium application nozzle 15, the casting roll contact medium tank 14 provided with a screw feeder, the rotary encoder 18, the counter 24, and the arithmetic processing unit 23 are arranged in contact with the slab 51 and rotate. A casting roll contact medium supplying means is provided which intermittently supplies the casting roll contact medium 16 which is in the form of paste or powder on the outer peripheral surface and which is in a liquid state by contacting the cast piece 51.

  The measuring unit 19 including the pulsar 20, the receiver 21, the A / D converter 22, the counter 24, and the arithmetic processing unit 23, and the rotary encoder 18 are in contact with the casting roll contact medium 16 in a liquid state. The ultrasonic roll S2 received by the ultrasonic probe 11 when the casting roll 52 and the slab 51 are in contact with each other through the casting roll 52 and the slab 51 without the casting roll contact medium 16 being present. The interface echo between the solidified layer 51a and the unsolidified layer 52b of the slab 51 is obtained from the difference (S2-S1) from the ultrasonic echo S1 received by the ultrasonic probe 11 when the The measuring means for obtaining the slab solidified layer thickness based on the boundary surface echo is configured.

  The operation of the slab solidified layer thickness detecting device configured as described above will be described with reference to FIGS. 2 to 4 together with FIG. 2 is a flowchart showing a procedure for detecting a solidified layer thickness by the slab solidified layer thickness detecting device shown in FIG. 1, and FIG. 3 is an explanatory diagram showing an example of an ultrasonic echo by the slab solidified layer thickness detecting device shown in FIG. 4 is a diagram showing the concept of ultrasonic echo difference processing by the slab solidified layer thickness detection apparatus shown in FIG.

  Here, prior to the description of the operation, the ultrasonic echoes S1 and S2 received by the ultrasonic probe 11 will be described.

  The ultrasonic echo S1 received by the ultrasonic probe 11 when the casting roll 52 and the slab 51 are in contact with each other without the casting roll contact medium 16 is shown in FIG. First, the casting roll surface echo ES, then the casting roll bottom surface echo EB1, then the second casting roll bottom surface echo EB2, and the third casting roll bottom surface echo (not shown) are observed. The waveform has a component. That is, when the casting roll 52 and the slab 51 are in contact with each other without using the casting roll contact medium 16, the ultrasonic wave from the ultrasonic probe 11 is not transmitted into the slab 51, and the slab 51. The interface echo E between the solidified layer 51a and the non-solidified layer 51b is not observed.

  On the other hand, the ultrasonic echo S2 received by the ultrasonic probe 11 when the casting roll 52 and the slab 51 are in contact with each other via the casting roll contact medium 16 is transmitted from the ultrasonic probe 11. Since ultrasonic waves are also transmitted into the slab 51, as shown in FIGS. 3 and 4, (a), the casting roll surface echo ES, the first casting roll bottom surface echo EB1, and the second casting roll bottom surface echo. The boundary surface echo E from the inside of the EB2 and the slab 51 becomes a waveform having each echo component to be observed. (In this case, as shown in FIG. 3 and FIG. 4A, the boundary surface echo E has an echo intensity (echo level) smaller than the echo intensity of the casting roll bottom surface echo EB1, EB2, (It may also overlap with the casting roll bottom echoes EB1 and EB2 in terms of time.)

  In the cast slab solidified layer thickness detecting apparatus configured as described above, first, the rotation angle of the casting roll 52 at that time is read (step 101). The arithmetic processing unit 23 reads the rotation angle from the count value of the counter 24 connected to the rotary encoder 18 and stores the rotation angle θ1.

  Next, the casting roll contact medium 16 is applied (step 102). The arithmetic processing unit 23 outputs a casting roll contact medium application command and drives a motor for rotating the screw feeder in the casting roll contact medium tank 14 for a predetermined short time. Thus, a predetermined amount of the casting roll contact medium 16 is applied to the outer peripheral surface of the casting roll 52 by the casting roll contact medium application nozzle 15 for a short time.

  Next, the ultrasonic echo S1 is read (step 103). The arithmetic processing unit 23 reads and stores the ultrasonic echo from the receiver 21 via the A / D converter 22 immediately after the output of the casting roll contact medium application command. Thereby, the ultrasonic echo S1 received by the ultrasonic probe 11 when the casting roll 52 and the cast piece 51 are in contact with each other without using the casting roll contact medium 16 (shown in FIG. 4B). Is obtained.

  Next, it is determined whether or not the rotation angle of the casting roll 52 is θ1 + Δθ2 (step 104). Here, the angle difference Δθ <b> 2 is an angle difference between the casting roll contact medium application position on the casting roll 52 and the contact position with the cast piece 51, and is 90 degrees as shown in FIG. 1 in this embodiment.

  Next, when the rotation angle of the casting roll 52 becomes θ1 + Δθ2 (YES in step 104), the ultrasonic echo S2 is read (step 105). When the count value of the counter 24 becomes a value obtained by adding a count value corresponding to the preset angle difference Δθ2 to the arithmetic processing unit 23, the casting roll 52 is used for the casting roll. Knowing that it has rotated by the angle difference Δθ2 from the time when the contact medium 16 is applied, the ultrasonic echo from the receiver 21 is read via the A / D converter 22 and stored. As a result, the ultrasonic echo S2 received by the ultrasonic probe 11 when the casting roll 52 and the cast piece 51 are in contact via the casting roll contact medium 16 (see FIGS. 3 and 4A). Is obtained).

  Next, the boundary surface echo E between the slab solidified layer 51a and the unsolidified layer 51b is detected based on the difference (S2-S1) between the two ultrasonic echoes S2 and S1 (step 106). The arithmetic processing unit 23 obtains a difference between the ultrasonic echo S2 and the ultrasonic echo S1. As a result, as shown in FIG. 4C, the influence of the multiple echoes EB1 and EB2 due to the presence of the casting roll 52 is eliminated, and the solidified layer 51a of the slab 51 and the unsolidified layer are echoes from the slab 51. Only the interface echo E from the interface with the layer 51b can be accurately detected with an excellent S / N ratio.

  Next, the time difference t between the casting roll bottom surface echo EB1 (slab surface echo) and the boundary surface echo E is calculated, and the slab is calculated from the time difference t and the sound speed in the slab 51 (sound speed in the slab solidified layer). The solidified layer thickness d is calculated (step 107). The arithmetic processing unit 23 detects the peak position of the boundary surface echo E detected by the difference, and the peak position of the boundary surface echo E and the peak position of the casting roll bottom surface echo EB1 (slab surface echo) in the ultrasonic echo S2. Is calculated, and the calculated time difference t is multiplied by the speed of sound in the slab 51 to calculate the slab solidified layer thickness d of the slab 51.

  Next, the calculated slab solidified layer thickness d is displayed on the display unit 25 (step 108). The arithmetic processing unit 23 outputs the calculated slab solidified layer thickness d to the display unit 25 and outputs it to an external control system as necessary. When the calculated slab solidified layer thickness d is smaller than the thickness setting value, the casting speed is reduced, and when it is thicker than the thickness setting value, the cast speed is increased.

  After step 108, the process returns to step 101, where the casting roll contact medium 16 is applied at equal intervals and the slab solidified layer thickness d is detected at a predetermined number of times during one rotation of the casting roll 52. Is to be done. For example, the application of the casting roll contact medium 16 and the detection of the slab solidified layer thickness d are performed only once during one rotation of the casting roll 52.

  As described above, the slab solidified layer thickness detection apparatus according to the present embodiment detects the solidified layer thickness of the slab 51 by the ultrasonic probe 11 through the casting roll 52 that rotates in contact with the slab 51. The casting roll contact medium 16 made of a low melting point material such as graphite paste and casting powder is intermittently supplied to the outer peripheral surface of the casting roll 52 by a predetermined amount. When it approaches the slab 51 with rotation and reaches the contact point between the casting roll 52 and the slab 51, it becomes liquid by heat due to contact with the high-temperature slab 51, and between the casting roll 52 and the slab 51. It is configured to be supplied as an ultrasonic contact medium (ultrasonic transmission medium). Therefore, unlike the water jet, the contact medium can be stably and quantitatively supplied between the casting roll 52 and the slab 51 without adversely affecting the slab quality. It is possible to prevent the decrease and maintain high solidified layer thickness detection sensitivity.

  Further, when the casting roll contact medium 16 is intermittently supplied to the outer peripheral surface of the casting roll 52, and the casting roll 52 and the cast piece 51 are in contact with each other through the casting roll contact medium 16 in a liquid state. The ultrasonic echo S2 received by the ultrasonic probe 11 and the ultrasonic wave received by the ultrasonic probe 11 when the casting roll 52 and the cast piece 51 are in contact without the casting roll contact medium 16. A difference from the echo S1 is taken. Thus, the influence of the multiple echoes EB1 and EB2 due to the presence of the casting roll 52 is eliminated, and only the boundary surface echo E between the solidified layer and the unsolidified layer of the slab 51, which is an echo from the slab 51, is excellent. / N ratio can be detected with high accuracy, and the slab solidified layer thickness d can be obtained with high accuracy based on the boundary surface echo E. Therefore, the thickness of the slab solidified layer can be accurately detected without adversely affecting the slab quality, and the continuous casting machine can be stabilized and contribute to an operation with high productivity.

  FIG. 5 is a configuration explanatory view of a slab solidified layer thickness detecting device of a continuous casting machine according to another embodiment of the present invention. Here, the configuration of the slab solidified layer thickness detecting device shown in FIG. 1 is the same as that of the cast slab solidified layer thickness detecting device shown in FIG. 1 except that the ultrasonic probe 11 is arranged inside the casting roll 52 ′ filled with the cooling liquid 58. Therefore, the same parts as those in the slab solidified layer thickness detecting apparatus shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

  According to the slab solidified layer thickness detecting apparatus according to this embodiment, as shown in FIG. 5, the cooling liquid 58 for cooling the casting roll 52 ′ filled in the casting roll 52 ′ is good for the ultrasonic probe 11. It is a contact medium. This makes it possible to accurately detect the thickness of the slab solidified layer without adversely affecting the quality of the slab while ensuring the thermal protection of the ultrasonic probe 11.

It is composition explanatory drawing of the slab solidified layer thickness detection apparatus of the continuous casting machine by one Embodiment of this invention. It is a flowchart which shows the solidification layer thickness detection procedure by the slab solidification layer thickness detection apparatus shown in FIG. It is explanatory drawing which shows an example of the ultrasonic echo by the slab solidified layer thickness detection apparatus shown in FIG. It is a figure which shows the concept of the difference process of the ultrasonic echo by the slab solidified layer thickness detection apparatus shown in FIG. It is composition explanatory drawing of the slab solidified layer thickness detection apparatus of the continuous casting machine by another embodiment of this invention. It is a perspective view which shows the whole structure of a continuous casting machine. It is explanatory drawing of the conventional contact medium supply means in a continuous casting machine. It is explanatory drawing of the conventional contact medium supply means in a continuous casting machine. It is explanatory drawing of the conventional contact medium supply means in a continuous casting machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Ultrasonic probe 12 ... Probe contact medium application nozzle 13 ... Probe contact medium 14 ... Casting roll contact medium tank 15 ... Casting roll contact medium application nozzle 16 ... Casting roll contact medium 17 ... Contact medium removal mechanism 18 ... Rotary encoder 19 ... Measurement unit 20 ... Pulsar 21 ... Receiver 22 ... A / D converter 23 ... Calculation processing unit 24 ... Counter 25 ... Display part 51 ... Slab 51a ... Solidified layer 51b ... Unsolidified Layer 52, 52 '... Casting roll 58 ... Cooling liquid

Claims (3)

In the slab solidified layer thickness detection device of the continuous casting machine that detects the solidified layer thickness of the slab by ultrasonic waves,
A casting roll contact medium supply means for intermittently supplying a casting roll contact medium made of a low melting point material in the form of a paste or powder to the outer peripheral surface of the casting roll rotating in contact with the slab;
An ultrasonic probe that is positioned on a substantially normal to the outer peripheral surface of the slab at a contact point between the casting roll and the slab, and is brought into contact with the casting roll via a contact medium;
The ultrasonic echo received by the ultrasonic probe when the casting roll and the slab are in contact with each other via the casting roll contact medium and the casting roll contact medium do not exist. By detecting the interface echo between the solidified layer and the unsolidified layer of the slab by the difference between the ultrasonic echo received by the ultrasonic probe when the roll is in contact with the slab, A slab solidified layer thickness detection device for a continuous casting machine, comprising: a measuring unit that obtains a slab solidified layer thickness based on a boundary surface echo.   2. The slab solidified layer thickness detecting device for a continuous casting machine according to claim 1, wherein the ultrasonic probe is arranged inside a casting roll filled with cooling water. The slab solidified layer thickness detecting device for a continuous casting machine according to claim 1 or 2, wherein the low melting point material is graphite paste or casting powder.

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