JP6070605B2 - Steel continuous casting method - Google Patents

Description

  The present invention relates to a continuous casting method of steel that prevents a beam blank cast from being bent left and right.

  In continuous casting of steel, molten steel poured into a water-cooled mold is primarily cooled, a solidified shell is formed on the inner wall of the mold to form a slab, and the slab is supported by a number of slab support rolls. The slab surface (solidified shell) is secondarily cooled by drawing, spray cooling water, or the like. At this time, the slab out of the mold may bend and advance in either the left or right direction.

  In order to correct the bending of the slab, a technique for adjusting the amount of cooling water supplied to the slab by secondary cooling has been proposed. In Patent Document 1, two series of slab cooling systems are used, the upper and lower surfaces of the slab are cooled using the first cooling system, and the side surfaces of the slab are cooled using the second cooling system. A technique for maintaining a cooling balance in the left-right direction in a slab cross-section substantially parallel to the slab has been proposed. Patent Document 2 proposes a technique for continuously measuring the bending of the slab slab that has exited the cooling chamber and controlling the water injection timing and amount of water for correcting the bending based on the measurement result. ing.

JP 60-68147 A JP-A-53-122624

  Applying the technology proposed in Patent Document 1 and Patent Document 2 to continuous casting of steel for casting slab slabs and bloom slabs, the amount of cooling water supplied to the slab during secondary cooling If adjusted, bending of the slab can be prevented. However, even if the techniques proposed in Patent Document 1 and Patent Document 2 are applied to continuous casting of steel for casting a beam blank slab, the left and right bending of the slab cannot be corrected in many cases. There is a case where the slab comes into contact with an unexpected part in the continuous casting machine and the slab is damaged.

  This invention is made | formed in view of the said situation, The place made into the objective is to prevent the bending of the said slab in the continuous casting of a beam blank slab.

  While the inventors can correct the bending of the slab slab or bloom slab by adjusting the amount of cooling water supplied by secondary cooling, the bending of the beam blank slab may not be corrected. Therefore, we focused on the differences in the continuous casting method between slab slabs and bloom slabs and beam blank slabs. When continuously casting slab slabs and bloom slabs, molten steel is injected into the center of the mold, which is approximately the same distance from both ends of the mold interior space. On the other hand, when beam blank slabs are continuously cast, Molten steel is injected into the flange. Due to this injection position, the inventors of the present invention in the beam blank cast slab, the thickness of the solidified shell to be formed differs on the left and right, and after the slab comes out from the mold, the solidified shells on the left and right flanges We thought that the difference in the thickness of the material became larger, which caused bending.

Therefore, the present inventors observed the left and right flange portions of the beam blank slab after the slab comes out of the mold, and based on the observation result, the amount of cooling water supplied to the left and right mold parts of the mold As a result, the present invention was completed to prevent the beam blank slab from being bent and advanced. That is, the gist of the present invention is as follows.
(1) Molten steel is injected into the flange portion of the mold blank space of the beam blank casting mold, and the molten steel is cooled by supplying cooling water to the mold to form a beam blank cast, and the beam blank cast A continuous casting method of steel that is pulled out while being supported by a roll, wherein the position of both flange surfaces of the beam blank slab is measured at the solidification completion position of the beam blank slab or in the casting direction downstream from the solidification completion position, The amount of heat removal is greater at the part of the mold that is in contact with the flange surface approaching the center line than at the part of the mold that is in contact with the flange surface away from the center line of the continuous casting machine. The continuous casting method of steel characterized in that the amount of the cooling water is adjusted.
(2) Molten steel is injected into the flange portion of the mold blank space of the beam blank casting mold, and the molten steel is cooled by supplying cooling water to the mold to form a beam blank cast, and the beam blank cast Is a continuous casting method of steel that is pulled out while being supported by a roll, wherein the thickness of both flange portions of the beam blank slab is measured at the solidification completion position of the beam blank slab or downstream of the solidification completion position in the casting direction. The amount of heat removal is larger at the part of the mold that is in contact with the surface of the other flange part with the larger thickness than the part of the mold that is in contact with the surface of the flange part with the smaller thickness. A method for continuously casting steel, wherein the amount of the cooling water is adjusted.
(3) Molten steel is poured into the flange portion of the mold blank space of the beam blank casting mold, and the molten steel is cooled by supplying cooling water to the mold to form a beam blank cast, and the beam blank cast Is a continuous casting method of steel that is pulled out while being supported by a roll, and measures the bulging amount of both flange surfaces of the beam blank slab from the outlet of the mold to the solidification completion position of the beam blank slab. The cooling is performed so that the amount of heat removal is larger in the part of the mold that is in contact with the other flange surface having the larger bulging amount than in the part of the mold that is in contact with the flange surface having the smaller bulging amount. A continuous casting method of steel characterized by adjusting the amount of water.

  ADVANTAGE OF THE INVENTION According to this invention, the bending of the slab which came out of the casting_mold | template can be prevented in the continuous casting of a beam blank. As a result, it is possible to prevent a situation in which the slab comes into contact with an unexpected part in the continuous casting machine and the slab is damaged, and the yield of the slab without a scratch can be improved.

It is explanatory drawing seen from the side of the continuous casting machine which performs an example of 1st Embodiment of this invention. (A) is sectional drawing of the casting_mold | template which casts a beam blank along the II-II line | wire shown in FIG. 1, (b) of the casting_mold | template which casts the bloom corresponded to the cross section shown to (a). It is sectional drawing. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 1. It is the IV-IV sectional view taken on the line shown in FIG. It is explanatory drawing seen from the side of the continuous casting machine which performs an example of 2nd Embodiment of this invention.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In the present invention, in continuous casting, the bending of the slab is detected on the left side and the right side with respect to the casting direction (detection of bending), and based on the detection result, the mold that has been in contact with the left or right flange surface is detected. Adjust the amount of cooling water supplied to the part (adjustment of heat removal amount). There are two embodiments of the present invention in which the positions for detecting the bending are different.

<First Embodiment>
FIG. 1 is an explanatory diagram viewed from the side of a continuous casting machine that performs an example of the first embodiment of the present invention, and a part of the continuous casting machine is shown in a vertical section for the sake of explanation. The continuous casting machine 1 casts a beam blank slab 2. The continuous casting machine 1 includes a beam blank casting mold 4, a tundish 5 installed above the mold 4, a plurality of guide rolls 11 arranged below the mold 4 along the casting direction A, and a plurality of guide rolls 11. The sensor 20a is installed between the guide rolls 11 and measures the surface position of the slab 2 and a plurality of pinch rolls 21 arranged downstream of the guide roll 11 in the casting direction A.

  Above the tundish 5, a ladle 6 that houses the molten steel 3 is installed. Molten steel 3 is poured into the tundish 5 through a long nozzle 7 provided at the bottom of the ladle 6. In a state where a predetermined amount of molten steel 3 stays in the tundish 5, the molten steel 3 is poured into the mold 4 through the immersion nozzle 8 installed at the bottom of the tundish 5. A cooling water channel 4c (see FIG. 2A) is formed in the mold 4 and the cooling water is passed through the cooling water channel 4c. Thereby, the molten steel 3 is extracted from the inner surface of the mold 4 and solidified to form a solidified shell 9a, and an unsolidified layer 9b is formed inside the solidified shell 9a.

  The guide roll 11 is composed of a plurality of rolls so as to be suitable for supporting the beam blank cast slab 2, and the pinch roll 21 is composed of a pair of upper and lower rolls. While the slab 2 is supported by the guide roll 11, the pinch roll 21 rotates while sandwiching the slab 2, and the slab 2 having the solidified shell 9 a and the unsolidified layer 9 b inside is pulled out. A plurality of transport rolls 13 are arranged downstream of the pinch roll 21, and a gas cutting machine 14 for cutting the slab 2 in synchronism with the drawing speed of the slab 2 is installed above the transport roll 13. ing. The cut slab 2 is sent to the next process.

  In the range where the guide roll 11 and the pinch roll 21 are disposed, the guide roll 11 and the pinch roll 21 are divided from the position immediately below the mold 4 toward the downstream in the casting direction A, and divided into the upper surface side and the lower surface side with the slab 2 interposed therebetween. A plurality of next cooling zones 15 are provided. Each secondary cooling zone 15 is configured such that the amount of secondary cooling water can be adjusted independently, and each secondary cooling zone 15 has a spray nozzle (not shown) such as a water spray nozzle or an air mist spray nozzle. Is provided between each of the guide roll 11 and the pinch roll 21, and the secondary cooling water is sprayed on the surface of the slab 2 or the secondary cooling water is sprayed together with air. As a result, the solidified shell 9a is cooled while being supported and conveyed by the guide roll 11, the solidification of the unsolidified layer 9b proceeds, and the solidification of the slab 2 (unsolidified layer 9b) is completed.

  Between the guide roll 11 and the pinch roll 21, a set of fixed guides 22 is installed on both sides in the width direction of the slab 2. When starting continuous casting, the rolls constituting the pinch roll 21 are arranged. A dummy bar (not shown) is passed through the gap, the gap of the fixed guide 22, and the gap of the roll constituting the guide roll 11, and the dummy bar is fitted into the mold 4 from below the mold 4. The molten steel 3 is poured into the mold 4 with the dummy bar fitted therein and the heat is removed to form the solidified shell 9a. Next, the dummy bar is pulled out, and the fixed guide 22 and the cast piece 2 are guided to the pinch roll 21 while the dummy bar and the cast piece 2 following the dummy bar are supported by the guide roll 11. Next, the dummy bar is appropriately removed by the pinch roll 21 and the cast piece 2 is pulled out by the pinch roll 21 to perform continuous casting of the cast piece 2.

  In this continuous casting, when the slab 2 bends to the left and right, the slab 2 comes into contact with the fixed guide 22 and is damaged. Previously, the amount of secondary cooling water supplied in the secondary cooling zone 15 has been adjusted to try to correct this bend. In slab slabs and bloom slabs, it is possible to correct the bend to a desired level. there were. However, in particular, when trying to correct the left and right bends of the beam blank cast slab 2, although the bend can be corrected to some extent, it cannot be corrected to a desired degree.

  The present inventors diligently studied the cause of the beam blank cast 2 being bent left and right, and the thickness of the solidified shell 9a of the beam blank cast 2 when exiting the mold 4 may not be the same on the left and right. Thus, it was speculated that the degree of growth of the solidified shell 9a differs between the left and right sides of the slab 2 as a cause of bending. First, the formation mechanism of the solidified shell 9a in the mold 4 for forming the beam blank cast 2 will be described.

  Fig.2 (a) is sectional drawing of the casting_mold | template 4 which forms the beam blank cast piece 2 along the II-II line | wire shown in FIG. FIG. 2B shows a cross-sectional view of a mold 104 for casting a bloom cast for comparison with the mold 4. As shown in FIG. 2 (a), the mold 4 is composed of two opposed mold long sides 4a and two opposed mold short sides 4b housed inside the mold long sides 4a. . The mold 104 is also composed of two opposite mold long sides 104a and two opposite mold short sides 104b housed inside the mold long sides 104a. Both the mold long sides 4a and 104a and the mold short sides 4b and 104b are provided with cooling water passages 4c and 104c. The cooling water passes through the cooling water passages 4c and 104c, and the molten steel starts from the inner surface of the molds 4 and 104. 3 is extracted and solidified, and solidified shells 9 a and 109 a are formed on the inner surface side of the molds 4 and 104. The mold 4 is different from the mold 104 in that the inner space has an H-shape, and the mold long side 4a has a central portion inside the mold so that the slab 2 has an H-shaped web portion 2a. Protruding to Molten steel 3 is poured into the mold 4 to cast an H-shaped beam blank cast 2 having a web portion 2a and a flange portion 2b.

  When the beam blank slab 2 is formed with the mold 4, when viewed from above the mold 1, it is away from either the left or right side from the center position that is the same distance from the left and right ends, that is, from the mold center line (dotted line). The molten steel 3 is injected into the flange portion of the mold inner space which is separated. FIG. 2A shows a case where molten steel 3 is injected into the right flange portion. The molten steel 3 is removed from the inner surface of the mold 4, and a solidified shell 9 a is formed on the inner surface of the mold 4. When the immersion steel 8 is disposed near the solidified shell 9 a and the molten steel 3 is injected into the mold 4, There is a possibility that the immersion nozzle 8 contacts the solidified shell 9a and is bent or cast into the solidified shell 9a and pulled and broken. For example, if the immersion nozzle 8 is disposed at the position of the mold center line, the immersion nozzle 8 approaches the solidified shell 9a constituting the web portion 2a of the slab 2. Therefore, as shown in FIG. 2A, the immersion nozzle 8 is disposed at a position at the same distance from the solidified shell 9a formed on the web portion 2a and the right flange portion 2b. On the other hand, when forming the bloom cast slab with the mold 104, as shown in FIG. 2 (b), the immersion nozzles 8 are arranged at the center positions of the left and right ends as viewed from above the mold 1, that is, on the dotted lines. To do. If the immersion nozzle 8 is disposed at this position, the immersion nozzle 8 is disposed at a position away from the solidification shell 109a by the same distance.

  When the immersion nozzle 8 is disposed at the center position of the mold 104 as shown in FIG. 2B, the flow of the molten steel 3 from the immersion nozzle 8 is directed in the same way to the left and right mold short sides 104b, and the solidified shell 109a is It grows in the same way on the left and right, and when exiting the mold 104, the thickness is substantially the same. On the other hand, as shown in FIG. 2A, when the immersion nozzle 8 is disposed in the flange portion of the mold internal space, the flow of the molten steel 3 from the immersion nozzle 8 is more than the left mold short side 4b. When the right mold short side 4b is reached earlier, the solidification progress of the right solidified shell 9a is delayed than the left solidified shell 9a, and the thickness of the right solidified shell 9a may be reduced. The present inventors have confirmed empirically. Although it is described as “empirically confirmed”, it is difficult to accurately measure the solidified shell 9a online, but if the obtained slab 2 is examined, formation of the solidified shell 9a is described. Based on being able to confirm the state to some extent.

  Based on the above description, the inventors of the slab 2 have a larger bulging amount on the side where the solidified shell 9a is thin than on the side where the solidified shell 9a is thick. It was inferred that the slab 2 was bent and advanced toward the smaller amount. The experiment was repeated, and it was confirmed that the slab 2 was bent and progressed from one flange portion of the mold inner space toward the flange portion on the opposite side. Next, the mechanism of the bending phenomenon of the slab 2 will be described.

  3 is a cross-sectional view taken along the line III-III shown in FIG. The guide roll 11 installed in the vicinity of the mold 4 supports a pair of web rolls 11a for supporting the upper and lower surfaces of the web portion 2a and the upper and lower surfaces of the flange portion 2b in order to appropriately support the H shape. It comprises a set of tip rolls 11b and flange rolls 11c and 11d that support the left and right side surfaces of the flange portion 2b. As the slab 2 moves away from the mold 4, the slab 2 is cooled and the solidification of the unsolidified layer 9 b is promoted, and the slab 2 is solidified. As shown in FIG. 1, the guide roll 11 that supports the slab 2 after the position (solidification completion position) 10 after the slab 2 completes solidification has been completed, and the flange portion 2b There are no flange rolls 11c and 11d for supporting the left and right side surfaces of the web roll 11a, and the web roll 11a and the tip roll 11b are used. The solidification completion position 10 can be obtained in advance by heat transfer solidification calculation.

  As shown in FIG. 3, the slab 2 is sandwiched between a pair of web rolls 11 a and a pair of tip rolls 11 b and is sandwiched between flange rolls 11 c and 11 d from the left and right side surfaces, and is cast between each guide roll 11. The bulging deformation occurs on the piece 2. During bulging deformation, the right flange portion 2b with a thin solidified shell 9a is assumed to have a larger bulging deformation amount than the left flange portion 2b. This is because the thinner the solidified shell 9a is, the more difficult it can withstand the static pressure of the molten steel, and the easier it is to swell. However, at a position close to the mold 4, the solidified shell 9 a itself does not undergo plastic deformation even though the amount of bulging deformation is large due to the thin solidified shell 9 a. While the slab 2 moves in the casting direction A, the solidified shell 9a moves in the casting direction A while a force is applied to the solidified shell 9a in the upward and inward directions by the contact of the guide roll 11. The force applied to the solidified shell 9a is transmitted to the unsolidified layer 9b where solidification has not progressed, and the unsolidified layer 9b also moves in the casting direction A while applying a force upward and inward. That is, since the unsolidified layer 9b absorbs the force applied to the solidified shell 9a, the solidified shell 9a is not plastically deformed.

  On the other hand, the solidification shell 9a becomes thicker as it gets away from the mold 4 and approaches the solidification completion position 10, and the bulging deformation amount becomes relatively smaller than the deformation amount at a position near the mold 4. Nevertheless, the solidified shell 9a itself is easily plastically deformed. This is because the solidified layer 9b has been solidified, and the guide roll 11 at a position close to the solidification completion position 10 does not absorb the force applied to the solidified shell 9a, and the solidified shell 9a is subjected to bulging deformation. This is because the guide roll 11, particularly the flange rolls 11 c and 11 d, is stretched (plastically deformed) toward the casting direction A. In addition, when the slab 2 exceeds the solidification completion position 10, bulging deformation does not occur in the slab 2. This is because at the solidification completion position 10, the unsolidified layer 9b has already solidified and no longer exists.

  FIG. 4 is a cross-sectional view taken along the line IV-IV shown in FIG. 1 and shows a cross-sectional view of the slab 2 in the vicinity of the solidification completion position 10. In FIG. 4, the center line 40 of the continuous casting machine 1 is shown as a one-dot chain line on the drawing. As shown in FIG. 4, the thickness d of the right flange portion 2b where the solidified shell 9a is thin is larger than the thickness d 'of the left flange portion 2b. While the slab 2 moves in the casting direction A, the solidified shell 9a extends to extend the right flange portion 2b from the left flange portion 2b, so that the surface of the right flange portion 2b approaches the center line 40. The surface of the left flange portion 2b moves away from the center line 40.

The above is the mechanism of the bending phenomenon of the beam blank slab 2, but this bending is due to the fact that the thickness of the solidified shell 9a of the beam blank slab 2 when exiting the mold 4 is not the same on the left and right, In view of this cause, the present inventors detect the bending of the slab 2 and change the heat removal amount of the left and right mold parts (the mold short side 4b) in the mold 4 to eliminate this cause. I came up with it. The steel continuous casting method according to an example of the first embodiment of the present invention includes the following two steps.
1. In continuous casting, the bending of the slab 2 on the left side and the right side with respect to the casting direction A is detected downstream of the solidification completion position 10 of the slab 2 or the casting direction A from the solidification completion position 10 (detection of bending). .
2. Above 1. Based on the result, the amount of cooling water supplied to the portion of the mold (mold short side) that was in contact with the left or right flange surface is adjusted (adjustment of heat removal amount).

  Above 1. 1. detection of bending and There are the following two methods for adjusting the amount of heat removal. In the first method, the surface positions of the left and right flange portions 2b of the slab 2 are continuously measured, and the surface position is shifted to the left or right, that is, the surface position is the continuous casting machine 1. It is detecting that it leaves | separates from the center line 40 (refer FIG. 4), and adjusts the amount of heat removal based on the result. It is expected that the solidified shell 9a formed by the mold short side 4b that is in contact with the surface of the flange portion 2b approaching the center line of the continuous casting machine is thin and the flange portion 2b extends. Therefore, the amount of heat removal at the mold short side 4b that is in contact with the surface of the flange portion 2b approaching the center line 40, which is expected to extend, is reduced to the surface of the flange portion 2b that is away from the center line 40. What is necessary is just to adjust the quantity of cooling water so that it may become larger than the casting_mold | template short side 4b which was contacting.

  The second method is to measure the thickness of the left and right flange portions 2b of the slab 2 and adjust the amount of heat removal based on the result. It is expected that the solidified shell 9a formed by the mold short side 4b in contact with the flange portion 2b having a large thickness is thin and the flange portion 2b is elongated. Therefore, the amount of heat removal in the mold short side 4b that is in contact with the surface of the flange portion 2b having a large thickness expected to be extended is smaller than that in the mold short side 4b in contact with the surface of the flange portion 2b having a small thickness. However, what is necessary is just to adjust the quantity of cooling water so that it may become large.

  The measurement of the surface position of the flange portion 2b and the measurement of the thickness of the flange portion 2b in the above two methods may be performed by the sensor 20a, or may be performed visually if possible. The sensor 20a is not particularly limited as long as it fulfills the measurement function. For example, a touch roller type or an optical type such as laser reflection can be adopted. The sensor 20a may be disposed downstream of the solidification completion position 10 or the casting direction A from the solidification completion position 10. In FIG. 1, the sensor 20 a is arranged at an appropriate position downstream in the casting direction A from the solidification completion position 10. Since the degree of deviation of the flange surface position from the center line of the continuous casting machine increases as the distance from the solidification completion position 10 increases, for example, at the installation position of the fixed guide 22 in FIG. The degree of deviation can be easily grasped.

Second Embodiment
Next, an example of the second embodiment of the present invention will be described. FIG. 5 is an explanatory diagram viewed from the side of a continuous casting machine that performs an example of the second embodiment of the present invention. 5 that are the same as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1 and description thereof is omitted. The continuous casting machine 31 according to the example of the second embodiment is common to the continuous casting machine 1 according to the example of the first embodiment in that it has a sensor and a configuration other than the sensor. However, the continuous casting machine 31 is different from the continuous casting machine 1 in that the measurement target of the sensor 20b is the bulging amount of the slab 2 and the installation position of the sensor 20b.

The continuous casting method of steel according to an example of the second embodiment of the present invention includes the following two steps.
1 '. In continuous casting, the bending of the slab 2 on the left side and the right side with respect to the casting direction A is detected between the outlet of the mold 4 and the solidification completion position 10 (detection of bending).
2 '. 1 '. Based on the result, the amount of cooling water supplied to the portion of the mold (mold short side) that was in contact with the left or right flange surface is adjusted (adjustment of heat removal amount).

  1 '. Detection of bending and 2 '. As a method of adjusting the amount of heat removal, first, the amount of heat removal is adjusted by measuring the amount of bulging and then adjusting the amount of heat removal. As described in the portion explaining the first embodiment, the difference in the thickness of the left and right flange portions 2b is caused by the difference in the thickness of the left and right solidified shells 9a. It occurs when the amount is different. In the casting direction A downstream of the solidification completion position 10 and the solidification completion position 10, the unsolidified layer 9 b has not already solidified in the slab 2 and bulging deformation does not occur. Bulging deformation occurs up to just below 4, and in particular, the closer to the mold 4, the larger the bulging amount. Therefore, the amount of bulging on the surfaces of the left and right flange portions 2b (both flange surfaces) is measured from the outlet of the mold 4 to the solidification completion position 10.

  Next, based on the measurement results, the amount of heat removed from the mold short side 4b that is in contact with the surface of the flange portion 2b on which the bulging amount is expected to be extended is reduced to the flange portion 2b on the side where the bulging amount is smaller. The amount of cooling water supplied to the left or right mold short side 4b may be adjusted so as to be larger than the mold short side 4b in contact with the surface.

  The sensor 20b for measuring the bulging amount may be installed between the outlet of the mold 4 and the solidification completion position 10. However, since the molten steel scatters significantly at the breakout immediately below the mold 4 and the sensor 20b is easily burned out, the installation position of the sensor 20b is considered from the balance between the distance measurement performance of the sensor 20b and the risk of burnout of the sensor 20b at the breakout. Is preferably determined. In FIG. 5, the sensor 20 b is disposed at an appropriate position upstream in the casting direction A from the solidification completion position 10. The sensor 20b may be the same as the sensor 20a. For example, a touch roller type or an optical type such as laser reflection can be adopted.

  By the above method, it is possible to prevent bending of the slab out of the mold in the continuous casting of the beam blank. This prevents the situation where the beam blank slab comes into contact with an unexpected part in the continuous casting machine and damages the slab, and improves the yield of the slab without scratches. it can.

  The beam blank slab 2 was cast at a casting speed of 1 m / min by a beam blank continuous caster (a slab flange height of 400 mm, a flange interval of 470 mm, and a curved band radius of 15 m) shown in FIGS. 1 and 5. As described in the above-described embodiment, the surface positions of the left and right flange portions 2b of the slab 2 are continuously measured, and the surface positions are the center lines 40 of the continuous casting machine 1 and the continuous casting machine 31 (FIG. 4). (See below), and based on the result, the amount of heat removed from the short side 2b of the mold was adjusted, and the continuous casting was performed while preventing the beam blank slab 2 from being bent. Invention Example 1). Further, the thickness of the left and right flange portions 2b of the slab 2 is measured, and based on the result, the amount of heat removal from the mold short side 2b is adjusted to prevent the beam blank slab 2 from being bent and proceeding continuously. Casting was performed (Invention Example 2). Furthermore, it was performed by measuring the amount of bulging, and based on the result, the heat removal amount of the mold short side 4b was adjusted, and continuous casting was performed while preventing the beam blank cast piece 2 from being bent and advanced ( Invention Example 3).

  On the other hand, in order to compare the inventive examples 1 to 3, the beam blank slab 2 is the same as the inventive examples 1 to 3, except that the amount of cooling water supplied to both the mold short sides 4b is the same. Was cast (comparative example).

  In the comparative example, the surface corresponding to 15.7% of the total area of the side surfaces of all the cast beam blank slabs 2 was scratched by the contact of the fixed guide 22. On the other hand, in Examples 1 to 3 of the present invention, the surface corresponding to 1.6% of the total area of the side surfaces of all the cast beam blank slabs 2 need only be damaged by the contact of the fixed guide 22. . In the continuous casting method of steel of the present invention, the beam blank slab is prevented from being bent and the beam blank slab comes into contact with an unexpected part in the continuous casting machine, and the slab is damaged. It was confirmed that it was possible to prevent the situation that

1 Continuous casting machine (first embodiment)
2 Casting (beam blank casting)
2a Web part 2b Flange part 3 Molten steel 4 Mold (for beam blank casting)
4a Mold long side 4b Mold short side 4c Cooling channel 5 Tundish 6 Ladle 7 Long nozzle 8 Immersion nozzle 9a Solidified shell (of beam blank cast)
9b Unsolidified layer 10 Solidification completion position 11 Guide roll 11a Web roll 11b Tip roll 11c Flange roll 11d Flange roll 13 Transport roll 14 Gas cutting machine 15 Secondary cooling zone 20a Sensor (first embodiment)
20b sensor (second embodiment)
21 Pinch roll 22 Fixed guide 31 Continuous casting machine (second embodiment)
40 Central line of continuous casting machine 104 Mold (for bloom casting)
104a Mold long side 104b Mold short side 104c Cooling channel 109a Solidified shell (of Bloom cast)

Claims (1)

Injecting molten steel into the flange of the mold blank space inside the beam blank casting mold,
It is a continuous casting method of steel in which the molten steel is cooled by supplying cooling water to the mold to form a beam blank cast, and the beam blank cast is drawn while being supported by a roll,
Measure the thickness of both flange portions of the beam blank slab at the solidification completion position of the beam blank slab or downstream of the solidification completion position in the casting direction,
The portion of the mold that has been in contact with the surface of the other flange portion having the larger thickness than the portion of the mold that has been in contact with the surface of the flange portion having the smaller thickness so that the amount of heat removal is larger. A method for continuously casting steel characterized by adjusting the amount of cooling water.

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