JP2019115916A - Repair method and repair device for tundish refractory - Google Patents

Abstract

To provide a repair method and a repair device for a tundish refractory where, upon preparation of the reuse of a used tundish, when an MgO covering layer present at a surface layer of a lining refractory of the used tundish is removed, a smooth refractory surface is secured so as to be removed without producing ruggedness on the surface of the lining refractory.SOLUTION: Provided is a repair method for a tundish refractory where, on the basis of the measured result of a surface shape of the tundish refractory after the completion of casting, the thickness amount of the refractory to be removed on the surface side of the tundish refractory is calculated, and the calculated cutting thickness predetermined amount is cut using a milling removal apparatus 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method and a device for repairing refractories of tundish used in a continuous casting machine of steel production process, and more particularly, in preparation for reuse of used tundish, refractory lining of used tundish The present invention relates to a method and apparatus for efficiently and smoothly removing the MgO coating layer present in the surface layer of

  A tundish used in a continuous casting machine of a steel mill removes remaining steel in the tundish after casting and removes foreign matter adhering to the surface of a lining refractory (also referred to as "work refractory" or "work brick") (MgO coating layer, slag, bare metal, etc.) is removed, and a MgO coating layer is newly applied to the inner surface of the inner surface refractory and reused. If the damage to the lining refractory is large, the damaged part or the entire surface of the lining refractory is removed and a new lining refractory is applied and reused.

  Removal of such residual steel, removal of deposits on the inner surface of the inner surface of the refractory, and removal of the inner surface of the refractory are once performed by workers entering the tundish and having an impact action such as a pick breaker or a hammer drill. Although this was done manually using a tool, in recent years, the tundish has become large and the operation is so severe that specialized equipment has been used.

  For example, in Patent Document 1, a first outer cylinder supporting a first inner cylinder having a rotary cutter at its lower end movably supported and a second inner cylinder having a pick breaker installed at its lower end are elevatingly movable. The lining refractor pivotably supported by a swivel base provided on a movable carriage mounted on a traveling platform and supported by a form moving frame that contains in parallel and supported a second outer cylinder supported is a load dismantling device Proposed.

  In Patent Document 2, a profile measuring device for measuring the shape of a refractory lining surface, a profile storage device for storing an initially set profile, a comparison operation between the initially set profile and the measured profile, graphic processing And the automatic repair device of the refractory which is composed of the arithmetic control unit which calculates the repair method, the refractory spray device, and the refractory surface cutting and removing device and automatically measures and repairs the damaged portion of the refractory has been proposed. .

  In Patent Document 3, a tilting machine which holds and tilts a tundish, a traveling carriage which travels above the tilting machine, a traversing carriage which traverses on rails provided on the traveling carriage, and a traversing carriage are mounted. An elevator which can move up and down, a balancer and a cutting device which are pivotably attached to the elevator and move up and down together with the elevator, and a residual steel extruding device which can be moved in a transverse direction by a drive mechanism attached to a traveling carriage. A dismantling apparatus for the provided tundish refractories has been proposed.

  However, the devices disclosed in these prior arts are devices used for repair, removal, replacement of the inner refractory, etc. because the inner refractory is heavily damaged, and the inner refractory surface of the used tundish ( It can not be used as an apparatus for removing the MgO coating layer present on the working surface) and an apparatus for removing the infiltration layer of the lining refractory as needed simultaneously with or after the MgO coating layer. Here, the MgO coating layer is a MgO layer applied to the surface of the inner surface refractory to prevent the reaction between the molten steel and the inner surface refractory, and the wet layer of the inner surface refractory is continuous casting It is a site that is in contact with the slag inside the tundish and is degraded by penetration of the slag.

  Therefore, using a device called a dresser equipped with an uneven hammer on the outer periphery, as an apparatus for removing the MgO coating layer present on the surface layer of the used refractory of the tundish and the infiltration layer as needed. It was removed.

  However, in this device, it is difficult to control the amount of removal of the refractory, the amount of removal of the inner refractory is excessive as compared to the amount to be originally removed, and the surface of the inner refractory after removal causes asperities. ing. Therefore, the MgO coating layer can not be applied as it is with the above-mentioned removal by the dresser, and it becomes necessary to manually smooth the uneven portion of the inner refractory. By smoothing the uneven portion, labor (labor cost) for the smoothing construction is required, and there is a problem that a material for filling the concave portion at the time of the smoothing construction is necessary. Furthermore, since the refractory lining is removed in excess of the necessary amount at the time of removal, it is also a problem that a large amount of waste (waste) is generated during the removal process.

Japanese Utility Model Publication No. 58-32150 Japanese Utility Model Publication No. 61-178200 Japanese Patent Application Laid-Open No. 6-106332

  The present invention has been made in view of the above circumstances, and an object of the present invention is to remove the MgO coating layer present on the surface layer of used tundish lining refractory when preparing used tundish for reuse. The fire resistance of the tundish can be ensured by removing the surface of the inner refractory without generating irregularities on the surface of the inner surface refractory and reducing the amount of waste generated during the removal treatment. It is providing a thing repair method and a refractory repair device.

The gist of the present invention for solving the above-mentioned subject is as follows.
[1] Based on the measurement results of the surface shape of the tundish refractory after the end of casting, the thickness amount of the refractory to be removed on the surface side of the tundish refractory is calculated and calculated using a milling cutter. A method of repairing a tundish refractory characterized by cutting a predetermined amount of cutting thickness.
[2] When calculating the thickness amount of the refractory to be removed on the surface side of the tundish refractory, referring to the surface shape measurement history of the tundish refractory at the time of past repair construction, the refractory to be removed A method of repairing a tundish refractory according to the above [1], which comprises calculating the thickness of the steel.
[3] When cutting the tundish refractory using the milling cutter, the milling cutter contacts the metal remaining on the tundish, and the surface of the tundish is cut When it is missing more than the thickness predetermined amount, the surface shape of the tundish refractory is measured again after performing the originally planned cutting, and the above-mentioned milling cutter is made so that the surface of the tundish refractory becomes smooth. The method for repairing a tundish refractory according to the above [1] or [2], which is characterized by cutting again using.
[4] At the time of cutting of the tundish refractory, based on at least one of the measurement results of the surface shape measurement history of the tundish refractory at the time of repair work in the past and the surface shape of the tundish refractory at the time of repair this time A method of repairing a tundish refractory according to any one of the above [1] to [3], wherein discharge destinations of cutting chips generated at the time of cutting are classified.
[5] A shape measuring device for measuring the surface shape of a tundish refractory, an arithmetic device for calculating the thickness amount of the refractory to be removed based on the shape measurement result by the shape measuring device, and the calculation device And a milling and removal apparatus for cutting the thickness of the refractory to be removed.

  According to the present invention, since the MgO coating layer present on the surface layer of the inner refractory of the used tundish is removed using a milling cutter, the accuracy of cutting is improved, and the surface of the inner refractory is uneven. As a result, it is possible to secure a smooth surface of the refractory without causing a problem, and it is possible to omit the repair work of the uneven surface of the refractory by a manual operation which was conventionally required. Thereby, time saving and labor saving of repair work are realized. In addition, the amount of cutting removal is calculated based on the shape measurement result of the surface of the refractory, and the amount of cutting removal calculated by the milling cutter is accurately removed, so wastes generated along with removal of the refractory Less generation is achieved.

FIG. 1 (A) is a schematic view of a tundish used in continuous casting, and FIG. 1 (A) shows a situation where molten steel is continuously cast using the tundish, and FIG. 1 (B) is a tan after being used in continuous casting. It is a figure which shows the condition of a dish. It is the schematic which shows the example of embodiment of the repair method of the tundish refractories which concerns on this invention. It is an overview photograph of a cutting tool. It is the figure which compared the waste generation amount accompanying cutting removal with this invention example and a prior art example.

  Hereinafter, the present invention will be specifically described with reference to the attached drawings.

  FIG. 1 shows a schematic view of a tundish used in continuous casting. FIG. 1 (A) shows the situation where molten steel is continuously cast using a tundish on which a refractory is applied, and FIG. 1 (B) shows the situation of the tundish after the end of casting used in continuous casting.

  The outer shell of the tundish 1 used in a continuous casting machine for continuously casting molten steel has an iron shell 2, and on the inside of the iron shell 2, a permanent refractory 3 and an inner refractory 4 are applied. The permanent refractory 3 is in contact with the iron shell 2 or is applied to the iron shell side via a heat insulating material (not shown). A lining refractory 4 is applied to the inside of the permanent refractory 3. The permanent refractory 3 and the lining refractory 4 are both composed of a monolithic refractory or a molded brick. Since the refractory refractory 4 on the molten steel side is exposed to high temperature conditions, a refractory having a higher degree of fire resistance is usually used for the refractory refractory 4 than for the permanent refractory 3.

  The MgO coating layer 5 is applied to the surface of the lining refractory 4. The MgO coating layer 5 is composed of magnesia clinker or the like having an MgO purity of 90% by mass or more, and MgO utilizes the fact that it has a high melting point and a low oxidation degree and does not react with molten steel or slag. It is used for the prevention of pollution by tundish refractories. The MgO coating layer 5 is usually formed by spray application such as magnesia clinker powder.

  On the bottom of the tundish 1, a sliding nozzle 7 consisting of an upper nozzle 6, a fixed plate 7A and a sliding plate 7B, and an immersion nozzle 8 are installed. A molten steel supply flow path to the not shown) is formed. The sliding nozzle 7 is a device for controlling the supply flow rate of the molten steel 10 from the tundish 1 to the continuous casting mold. The upper nozzle 6 is fitted and installed in a nozzle receiving brick 9 installed through the permanent refractory 3 and the lining refractory 4.

  By continuously casting the molten steel 10, the MgO coating layer 5 is damaged, and it is necessary to apply a new MgO coating layer 5 every continuous casting of about 8 charges (the molten steel amount of about one charge is about 300 tons). . When the MgO coating layer 5 is newly applied, it is necessary to remove the used MgO coating layer 5 remaining on the surface of the lining refractory 4. In addition, during continuous casting, in some cases, bare metal (not shown) or slag (not shown) may intrude into the back side of the MgO coated layer 5 in such a case, and in that case, Need to be removed. If these are not removed, the application of the MgO coating layer 5 becomes difficult. The code | symbol 11 in FIG. 1 (B) is the infiltration layer of the site | part which the slag in the tundish and the lining refractory 4 contact during continuous casting, and the slag infiltrated into the lining refractory 4 etc.

  In the present invention, the remaining used MgO coating layer 5 present on the surface of the lining refractory 4, the bare metal or slag invading the back side of the MgO coating layer 5, and the need to Accordingly, in order to carefully remove the MgO coating layer 5 and to smooth the surface of the lining refractory 4, a part of the infiltration layer 11 of the lining refractory 4 is removed.

  FIG. 2 shows an embodiment of a method of repairing a tundish refractory according to the present invention in which a used tundish is repaired using a milling cutter. In FIG. 2, reference numeral 12 is a milling cutter / removal device, 13 is a cutting tool, 14 is a cutting blade, 15 is a cutting tool support shaft for supporting the cutting tool, 16 is a frame for holding the cutting tool support shaft, 17 is a shape measuring device , 18 are arithmetic units. Further, FIG. 3 shows an overview photograph of the cutting tool 13.

  In addition, although the milling cutter removal apparatus 12 is described in two places with respect to the tundish 1 in FIG. 2, the milling cutter removal apparatus 12 is movable, and the removal operation is possible at various positions. It shows that it is. Incidentally, the milling cutter / removal device 12 on the left side of the paper surface of FIG. 2 shows a state in which the side of the tundish 1 is being cut, while the milling cutter / removal device 12 on the right side of the paper surface of FIG. Shows the status of Moreover, the structure of the tundish 1 in FIG. 2 is the same as that of the tundish 1 shown in FIG. 1, and the description of the reference numerals is omitted.

  The cutting tool 13 rotates along the horizontal plane around the cutting tool support shaft 15 with the cutting tool support shaft 15 as an axis, and remains in the tundish with a plurality of cutting blades 14 installed on the outer periphery of the cutting tool 13 It is configured to be able to cut and remove oxides such as metal and refractory. The bottom surface of the tundish 1 is cut by a cutting blade 14 installed at the lower part of the outer periphery of the cutting tool 13. Further, the cutting tool support shaft 15 is configured to be vertically movable and movable in the longitudinal direction and the width direction of the tundish in a state of being held by the rack 16 and held by the rack 16.

  The repair apparatus for tundish refractories according to the present invention comprises a milling cutter / removal device 12, a shape measuring device 17 and an arithmetic device 18. The shape measuring device 17 is a device for measuring the surface shape of the tundish refractory, and the data measured by the shape measuring device 17 is transmitted to the arithmetic device 18. The computing device 18 is a device that computes the thickness amount (predetermined cutting thickness amount) of the refractory to be removed on the surface side of the tundish refractory based on the input data from the shape measuring device 17. The arithmetic unit 18 inputs the calculated thickness amount (predetermined cutting thickness amount) of the refractory to be removed to the control unit (not shown) of the milling and cutting removal device 12. The milling and removing apparatus 12 is configured to remove the planned cutting thickness input from the computing device 18.

  The shape measuring device 17 may be a device that measures the distance to the surface of the refractory using a laser distance meter or the like and measures the shape of the surface of the refractory from the measured distance data. When using a laser distance meter as the shape measuring device 17, it is preferable to install a plurality of laser distance meters to shorten the measurement time.

  In the repair method of tundish refractories according to the present invention, first, the surface shape of the tundish refractories of the used tundish is measured by using a shape measuring device 17 configured by a plurality of laser distance meters and the like. The computing device 18 calculates the trajectory of the cutting tool 13 based on the surface shape measurement result measured by the shape measuring device 17 input from the shape measuring device 17. That is, the arithmetic unit 18 calculates the thickness amount (cut thickness planned amount) to be removed of the tundish refractory. Furthermore, in order to remove more reliably, it is preferable to perform an additional 1.0 mm thick cutting. An additional 1.0 mm thick cut will cut the infiltration layer 11. The surface position of the lining refractory 4 serving as the reference position of the planned cutting thickness amount is the lining refractory 4 of the repair work of the tundish 1 at the time of major repair work of the tundish 1 stored at the computing device 18 in advance. Let it be the surface position.

  As long as the number of times of use of the tundish 1 is small, there is no problem even if the surface position of the inner refractory 4 serving as the reference position of the planned cutting thickness amount is the surface position of the inner refractory 4 at the time of major repair work of the tundish 1 However, when the number of times of use of the tundish 1 increases, the thickness of the inner refractory 4 decreases with the cutting and removal of the infiltration layer 11 performed as necessary. In that case, it becomes difficult to reliably remove the remaining MgO coating layer 5. In addition, when the infiltration layer 11 of the lining refractory 4 is removed as necessary, it is difficult to reliably remove the infiltration layer 11 of the lining refractory 4 without excessively cutting the lining refractory 4. Become.

  Therefore, when calculating the thickness amount to be removed of the tundish refractory (cut thickness planned amount), the surface shape measurement history of the tundish refractory at the time of the past repair construction stored in the arithmetic unit 18 is referred to, It is preferable to calculate the thickness amount (cut thickness planned amount) to be removed of the tundish refractory by integrating it with the shape measurement result of the tundish refractory at the time of repair of the refractory surface this time. That is, the surface shape measurement history of the tundish refractory at the time of past repair construction is compared with the shape measurement result of the tundish refractory this time, and the thickness amount to be removed of the tundish refractory (cut thickness planned amount) It is preferable to calculate. In this way, the remaining MgO coating layer 5 can be reliably removed without cutting the inner refractory 4 excessively.

  Thereafter, based on the calculated trajectory of the cutting tool 13, the milling / removing apparatus 12 cuts the surface of the tundish refractory. The surface of the tundish refractory after cutting by the milling and removing apparatus 12 has no unevenness, and a substantially smooth surface is obtained.

  Since the materials of the MgO coating layer 5 and the infiltration layer 11 of the refractory lining 4 are different, it is advantageous not to mix the two when they are recycled. Therefore, at the time of cutting of the tundish refractory, based on at least one of the measurement results of the surface shape of the tundish refractory at the time of repair work in the past and the measurement of the surface shape of the tundish refractory at the time of repair this time It is preferable to separate discharge destinations of cutting chips generated at the time of cutting. That is, it is preferable to separate and collect the cutting waste generated at the time of cutting of the MgO coating layer 5 and the cutting waste generated at the cutting of the infiltration layer 11 of the refractory lining 4.

  The MgO coating layer 5 is formed on the surface of the tundish refractory after cutting by spray application such as magnesia clinker powder, and the repair of the tundish 1 is completed.

  The surface shape of the tundish refractory is measured using the shape measuring device 17 at the completion of cutting by the milling cutter / removal device 12 and at the completion of repair after the formation of the MgO coating layer 5, and the result is used as the repair history. It is preferable to make the computer 18 record data. By referring this result as the removal target position at the next repair, it is possible to perform the next repair accurately and quickly.

  As described above, according to the present invention, since the MgO coating layer 5 remaining on the surface layer of the inner refractory 4 of the used tundish is removed using the milling cutter 12, the accuracy of cutting is improved. In addition, it is possible to secure a smooth surface of the refractory without generating irregularities on the surface of the inner surface refractory 4, and it is possible to omit the repair work of the surface of the refractory with the hand which has been conventionally required. Thereby, time saving and labor saving of repair work are realized. In addition, since the amount of cutting removal is calculated based on the shape measurement result of the surface of the refractory, and the amount of cutting removal calculated by the milling and removing apparatus 12 is precisely removed, waste generated along with removal of the refractory It is realized to reduce the generation amount of

  Using the tundish refractor repair device according to the present invention shown in FIG. 2, the MgO coating layer present on the surface layer of the used tundish lining refractory was cut off. As the shape measuring device, a device having a total of five laser range finders for measuring the distance to the front, rear, left, right, and lower refractory surfaces was used.

  With reference to the shape of the surface of the refractory by the shape measuring device and the past repair history result stored in the computing device, the thickness amount (cut thickness planned amount) to be removed using the computing device is calculated as a result, 10 An estimated cutting thickness of .0 mm was calculated. In order to remove it more reliably, it was decided to carry out additional cutting with a surface layer of 1.0 mm thickness. Additional surface layer 1.0 mm thickness cutting corresponds to cutting and removing the infiltration layer.

  Then, 11.0 mm of cutting removal was performed with respect to the refractory surface using the milling cutter removal apparatus. As a result, there was no unevenness on the surface of the tundish refractory after cutting by the milling and removal apparatus, and a smooth inner refractory surface was obtained. When cutting was completed, the shape measurement of the surface of the refractory was performed by a shape measuring device, and the result was recorded as a repair history in the arithmetic device.

  During cutting, during cutting of the surface layer of 10.0 mm, this portion corresponds to the portion of the MgO coating layer, so the swarf was sucked and collected in the dust box for the MgO coating layer to be discharged. After completion of the surface layer 10.0 mm cutting, the next surface layer 1.0 mm portion is the portion of the inner surface refractory or the portion of the inner surface refractory infiltrated with slag, so it is cut to separate it from the cuttings of the MgO coating layer. The powder suction duct was switched, and it was sucked and collected to the dust box for the interior refractory for discharge. Thereby, in the dust box for lining refractories, mixing of the other component to such an extent that troubles in recycling were not seen.

  Assuming that the mass of chips generated by the conventional repair method (conventional example) is 100%, the mass of chips generated by the repair (inventive example) to which the present invention is applied is 60% as shown in FIG. It was a degree. In all cases, about 48% is the part of the MgO coating layer that should originally be removed, but in the example of the present invention, the waste generation amount of the inner refractory decreases by about 40%, and the corresponding repair material for irregularities is saved. We were able to. That is, in the example of the present invention, the infiltration layer could be removed without excessive cutting and removal of the inner surface refractory, but in the conventional example, when cutting the inner surface refractory, the sound inner surface refractory together with the infiltration layer It was confirmed that it had been cut and deleted.

  With respect to the tundish different from Example 1, the same tundish refractor repair device as in Example 1 was used to cut off the MgO coating layer present on the surface layer of the used tundish lining refractory. As the shape measuring device, a device having a total of five laser range finders for measuring the distance to the front, rear, left, right, and lower refractory surfaces was used.

  With reference to the shape of the surface of the refractory by the shape measuring device and the past repair history result stored in the computing device, the thickness amount (cut thickness planned amount) to be removed using the computing device is calculated as a result, 10 An estimated cutting thickness of .0 mm was calculated. In order to remove it more reliably, it was decided to carry out additional cutting with a surface layer of 1.0 mm thickness. Additional surface layer 1.0 mm thickness cutting corresponds to cutting and removing the infiltration layer.

  Therefore, 11.0 mm of cutting was performed on the surface of the refractory using a milling cutter.

  During the cutting and removal, the applied current of the motor, which is a power source of the milling and cutting device, exceeds a preset threshold, so after performing the originally planned cutting, the tan within a period exceeding the threshold of the current The position of the milling cutter on the dish was recorded by means of the profilometer.

  After that, according to the information of the position range where the threshold value is exceeded, this portion is measured again by the shape measuring device, and as a result of precise scanning (measurement), the metal remaining on the back side of the MgO coating in the tundish is milled. A dent of about 100 mm × 300 mm was detected, which appeared to be a trace that was struck and peeled off by the blade of the cutting and removing apparatus. In other words, it was found that the surface of the tundish refractory is missing more than the planned cutting thickness. Therefore, the surface on which the periphery of the recess is substantially smooth is calculated, the tool path necessary for processing is calculated, and cutting is performed again by the milling cutter. As a result, the portion of the peeling mark was reworked into a surface which was generally smoothly continuous with the periphery.

  There was no unevenness on the surface of the tundish refractory after cutting, and a smooth, lined refractory surface was obtained. When cutting was completed, the shape measurement of the surface of the refractory was performed by a shape measuring device, and the result was recorded as a repair history in the arithmetic device.

DESCRIPTION OF SYMBOLS 1 Tundish 2 Iron skin 3 Permanent refractory 4 Lined refractory 5 MgO coating layer 6 Upper nozzle 7 Sliding nozzle 7A Fixing plate 7B Sliding plate 8 Immersion nozzle 9 Nozzle receiving brick 10 Molten steel 11 Infiltration layer 12 Milling removal device 13 Cutting Tool 14 Cutting blade 15 Cutting tool support shaft 16 Mounting base 17 Shape measuring device 18 Arithmetic device

Claims (5)

  The thickness of the refractory to be removed on the surface side of the tundish refractory is calculated based on the measurement result of the surface shape of the tundish refractory after the end of casting, and the cutting thickness calculated using the milling cutter. A repair method for a tundish refractory characterized by cutting a predetermined amount.   When calculating the thickness amount of the refractory to be removed on the surface side of the tundish refractory, referring to the surface shape measurement history of the tundish refractory at the time of past repair construction, the thickness amount of the refractory to be removed The method of repairing tundish refractories according to claim 1, characterized in that:   When cutting the tundish refractory using the milling cutter, the milling cutter is in contact with the metal remaining on the tundish, and the surface of the tundish is cut by the estimated thickness. If it is missing more than necessary, after performing the originally planned cutting, the surface shape of the tundish refractory is measured again, and the above-mentioned milling cutter is used so that the surface of the tundish refractory becomes smooth. The method for repairing a tundish refractory according to claim 1 or 2, characterized by cutting again.   At the time of cutting based on at least one of the surface shape measurement history of the tundish refractory at the time of repair work in the past and the measurement result of the surface shape of the tundish refractory at the time of repair this time The method for repairing a tundish refractory according to any one of claims 1 to 3, wherein discharge destinations of generated chips are classified. A shape measuring device for measuring the surface shape of a tundish refractory;
A computing device for calculating the thickness of the refractory to be removed based on the shape measurement result by the shape measuring device;
And a milling and removal apparatus for cutting the thickness amount of the refractory to be removed calculated by the arithmetic unit.