JP2017080771A - Mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for twin casting in which a temperature detection sensor can be fitted to an intermediate partition copper block.SOLUTION: A mold 1 for continuous casting in which a fiber Bragg grating sensor 5, which comprises plural thermally-sensitive parts 5a, 5b, 5c at plural places which measure temperatures of side walls 2a to 2d having molten steel surfaces with which a molten steel in the mold 1 is brought into contact and an intermediate partition copper block 3, is inserted from the side walls 2a to 2d and any one of a top face, an undersurface and a lateral face of the intermediate partition copper block 3.EFFECT: A work time required for installation when performing multipoint measurements can be shortened. Further, a temperature of the intermediate partition copper block of a mold for twin casting can be measured with respect to both molten steel surfaces.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a continuous casting mold, and more particularly to a continuous casting mold capable of measuring the temperature of a partition copper block of a twin casting mold.

  Conventionally, continuous casting molds have thermocouples attached to the copper side walls that make up the mold, and during continuous casting, the casting process in the mold is monitored for breakout prediction and process monitoring and analysis in the mold. ing.

  In the breakout prediction system, the presence or absence of restraint between the slab and the side wall is determined from the measured side wall temperature. At this time, since it is difficult to obtain a temperature distribution between adjacent temperature measurement positions, the information used for the determination is limited to the local temperature at the measurement position.

  Therefore, when a constraint occurs at a position away from the temperature measurement position, the constraint cannot be detected unless the constraint propagates on the surface of the slab and reaches the vicinity of the temperature measurement position. Therefore, in order to improve the accuracy of the breakout prediction system, it is necessary to increase the number of temperature measurement positions and narrow the interval between the temperature measurement positions.

  The thermocouple is attached by opening a thermocouple insertion hole from the back plate side opposite to the molten steel surface with which the molten steel on the side wall comes into contact. There are restrictions on the installation location due to equipment interference with the flow control device.

  Therefore, when the number of thermocouples attached to the side wall is increased, there are problems that it takes a long time for the attachment work and that the recovery work at the time of failure becomes difficult.

  Moreover, the mold for twin casting includes a partition copper block having two molten steel surfaces. Since this partition copper block is in a position where the two molten steel surfaces face each other, it is difficult to install a thermocouple due to structural problems, and as a result, the temperature of the partition copper block cannot be grasped. The prediction accuracy of breakout is reduced.

  Therefore, as a temperature measurement technique instead of a thermocouple, a technique using a fiber Bragg grating (FBG) sensor that detects a change in temperature or strain as a change in optical wavelength has been developed.

  This FBG sensor can improve the responsiveness of heat from the mold body and can easily detect the temperature change of the mold body, compared with the case where a thermocouple is used, and the prediction accuracy of breakout is improved. (See paragraphs 0010 and 0020 of Patent Document 1.)

  The mold with the FBG sensor attached is disclosed in Patent Document 2, but in the case of the mold disclosed in Patent Document 2, the FBG sensor is attached from the back plate side of the side wall as in the case of the thermocouple. The sensor is inserted and integrated with the side wall. Therefore, increasing the number of FBG sensors installed has the same problem as using a thermocouple. There is also a problem that the lifetime of the expensive FBG sensor is limited by the side wall lifetime.

Japanese Patent No. 4568301 Japanese Patent No. 5579174

  The problem to be solved by the present invention is that the mold disclosed in Patent Document 2 has the same FBG sensor mounting manner as that of a thermocouple. Therefore, when the number of FBG sensors to be installed is increased, the thermocouple It has the same problem as using. In addition, the lifetime of the expensive FBG sensor is limited by the side wall lifetime.

  An object of the present invention is to make it possible to attach an FBG sensor that has good heat responsiveness from the mold body and improves the prediction accuracy of breakout to a partitioning copper block of a mold for twin casting. is there. Another object of the present invention is to enable repeated use of the FBG sensor regardless of the side wall life.

  In the method of attaching the thermocouple from the back plate side of the side wall, the thermocouple cannot be attached to the partitioning copper block of the twin casting mold having the two molten steel surfaces facing each other.

  In addition, the temperature that can be measured with the thermocouple is the spot temperature of the detection part, and in order to obtain the temperature distribution of the entire mold with high accuracy, the number of thermocouples installed at the measurement position becomes an enormous amount. The work takes a long time, and the recovery work at the time of failure becomes difficult.

  Furthermore, since it is necessary to process a thermocouple insertion hole on the side wall from the back plate side to the measurement position, there is a restriction on the installation location due to equipment interference with a flow control device such as a cooling slit or electromagnetic stirring.

  Therefore, the inventors insert from the surface other than the back plate side opposite to the molten steel surface, that is, the upper surface, the lower surface, or the side surface of the side wall (in the case of a mold for twin casting, the side wall and the partition copper block). Then, by making it possible to measure the temperature at multiple points on the side wall, we studied a specification that can reduce the work load when performing multi-point measurement and suppress equipment interference.

The present invention has been made on the basis of the above examination by the inventors,
In continuous casting molds,
An FBG sensor having a plurality of heat sensing units for measuring the temperature of a side wall having a molten steel surface in contact with the molten steel of the mold (in the case of a twin casting mold, the side wall and the partition copper block) (In the case of a casting mold for twin casting, the main feature is that it is inserted from any one of the upper surface, the lower surface, and the side surface of the side wall and the partition copper block).

  In the present invention, the temperature of the side wall and the partition copper block is measured by the FBG sensor having a plurality of heat sensing units, so that the temperature at a plurality of locations in the casting direction or in the horizontal direction perpendicular to the casting direction is 1 It can be measured with two FBG sensors. In addition, unlike the case of using a thermocouple, it is not necessary to make an insertion hole for installing the FBG sensor at all the measurement points, and the workability is improved.

  Therefore, if one FBG sensor is inserted from any of the upper surface, the lower surface, and the side surface of the mold side wall and the partition copper block, the temperature can be measured at a plurality of locations in the casting direction or in the horizontal direction perpendicular to the casting direction. It is not necessary to attach the FBG sensor from the back plate side of the side wall. Further, conventionally, the temperature of the partitioning copper block of the twin casting mold, which was difficult to measure the temperature, can be measured on both molten steel surfaces.

  Accordingly, there is no restriction on the installation location due to equipment interference with a flow control device such as a cooling slit or electromagnetic stirring, and the work time required for installation when performing multipoint measurement can be shortened.

  In the present invention, when the FBG sensor is inserted into the protective tube and then inserted into the side wall or the partition copper block together with the protective tube, the FBG sensor can be used repeatedly.

  In this invention, there is no restriction | limiting of the installation place by installation interference with flow control apparatuses, such as a cooling slit and electromagnetic stirring, and the work time required for installation at the time of performing multipoint measurement can be shortened. Further, conventionally, the temperature of the partitioning copper block of the twin casting mold, which is difficult to measure the temperature, can be measured on both molten steel surfaces.

It is the figure which showed the installation position of the FBG sensor in the mold for twin casting used for the test. (A) is the temperature of the side wall measured by a thermocouple, (b) to (d) are the temperatures of the side wall and the partition copper block on the short side measured by the FBG sensor, and (e) is (a) to (d). It is the figure which showed the casting speed at the time of obtaining the measurement temperature shown by. In order to show the temperature measurement position of the short side wall and the partition copper block in the twin casting mold, the side wall on the short side of the strand on the left side in FIG. It is the figure which expanded and showed the side wall of the surface side, (a) is a case where the conventional thermocouple is used, (b) is a case where the FBG sensor of this invention is used.

  In the present invention, for the purpose of enabling the temperature detection sensor to be attached to the partitioning copper block of the twin casting mold, the upper and lower surfaces of the partitioning copper block are provided with the FBG sensor having a plurality of heat sensing portions. Realized by inserting from either side.

  Hereinafter, tests conducted for confirming the effects of the present invention and the results thereof will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram for explaining a twin casting mold 1 in which a partition copper block 3 is arranged in the middle between the side walls 2a and 2b on the short side. In this test, for example, a hole 4 is made in the casting direction from the F surface side of the side wall 2a of the strand on the left side of the paper and the L surface side of the partitioning copper block 3, and the FBG sensor 5 is inserted into this hole 4. During the casting, the temperatures of the side wall 2a and the partition copper block 3 were measured.

  The position of the hole 4 in the side wall 2a of the strand in the length direction of the short side of the mold of the side wall 2a was determined so that it could be compared with the temperature at the measurement position A when a conventional thermocouple was used. Also, the position in the casting direction was set to be the same as the measurement position A when the conventional thermocouple was used in the position 5b of the heat sensing portions 5a to 5c of the FBG sensor 5.

  On the other hand, the heat sensing parts 5a to 5c of the FBG sensor 5 inserted into the hole 4 of the partitioning copper block 3 are heat-sensing of the FBG sensor 5 inserted into the hole 4 opened in the side wall 2a of the strand. It was made to become the same position as parts 5a-5c.

  In order to accurately measure the temperature of the side wall 2a and the partition copper block 3, the FBG sensor 5, the side wall 2a, and the partition copper block 3 must be brought into close contact with each other. Therefore, in the test, the FBG sensor 5 was passed through the polyimide protective tube, fixed to a copper rod using Kepler yarn, and inserted into the hole 4.

  Fig. 2 shows the measured temperature when continuously casting a slab having a width of 1250mm and a thickness of 250mm at the casting speed shown in Fig. 2 (e) while supplying molten steel of low carbon steel to the above-mentioned twin casting mold 1. 2 (a) to (d).

  2A is a temperature at which the position A is measured using a thermocouple, FIG. 2B is a measured temperature at the heat sensing unit 5a of the FBG sensor 5, and FIG. 2C is a temperature at the heat sensing unit 5b. The measured temperature, FIG. 2D, is also the measured temperature in the heat sensing unit 5c. 2B, 2C, and 2D, for convenience, the first, second, and fifth casts show the temperature measurement results on the short side, and the third and fourth casts show the temperature measurement results on the partition side. Described.

  The measurement was continued for 40 hours. 2 (a) and FIG. 2 (c) are in good agreement, and since there is no difference between the initial stage and the final stage of the test, it has been found that there is no problem in the measurement accuracy of the present invention.

The present invention has been made based on the results of the above test,
For example, as shown in FIG. 3B in which the side wall 2a on the short side of the strand on the left side in FIG. 1, the side wall 2c on the L side, the partition copper block 3, and the side wall 2d on the F side are developed.
In the twin casting mold 1,
Three heat sensing parts 5a for measuring the temperatures of the short side walls 2a and 2b, the long side walls 2c and 2d, and the partition copper block 3 having the molten steel surface with which the molten steel of the mold 1 contacts. , 5b, 5c, the FBG sensor 5 is inserted from, for example, the upper surfaces of the side walls 2a to 2d and the partition copper block 3.

  According to the present invention described above, the number of measurement positions can be easily increased as compared with the conventional mold in which the thermocouple 6 shown in FIG. 3A is attached to the back plate side of the side walls 2a to 2d. . In addition, the FBG sensor 5 can be attached to both molten steel surfaces of the inner partition copper block 3 of the twin casting mold 1 where the thermocouple could not be attached, and the temperature of both molten steel surfaces of the inner partition copper block 3 can be measured. Is possible.

  The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

  For example, in the example described above, the present invention is applied to the twin casting mold 1, but the present invention is not limited to the twin casting mold 1.

  In the above example, the FBG sensor 5 is inserted and attached from the side walls 2a to 2d and the upper surface of the partition copper block 3, but the lower surface or side surface of the side walls 2a to 2d and the partition copper block 3 is shown. The FBG sensor 5 may be inserted and attached.

DESCRIPTION OF SYMBOLS 1 Twin casting mold 2a, 2b, 2c, 2d Side wall 3 Partition copper block 5 FBG sensor 5a, 5b, 5c Heat sensing part

Claims (3)

In continuous casting molds,
A fiber Bragg grating sensor having a plurality of heat sensing units for measuring the temperature of the side wall having the molten steel surface with which the molten steel of the mold contacts is inserted from any one of the upper surface, the lower surface, and the side surface of the side wall. A casting mold for continuous casting characterized by the above. In continuous casting molds,
A fiber Bragg grating sensor having a plurality of heat sensing parts for measuring the temperature of a side wall and a partition copper block having a molten steel surface with which the molten steel of the mold contacts, and an upper surface of the side wall and the partition copper block A continuous casting mold, which is inserted from any one of the lower surface and the side surface.   3. The continuous casting mold according to claim 1, wherein the fiber Bragg grating sensor is inserted into the side wall together with the protective tube after being inserted into the protective tube. 4.

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