Slab continuous casting crystallizer flow field detection device and method

Abstract

According to the slab continuous casting crystallizer flow field detection device and method, a mounting hole is formed in the end face of a crystallizer copper plate in the continuous casting throwing direction, the axis of the mounting hole is parallel to the working face of the crystallizer copper plate, and the distance between the axis of the mounting hole and the working face of the crystallizer copper plate is larger than or equal to 10 mm; a kerf is arranged on the working surface of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, the center line of the kerf and the axis of the mounting hole are positioned on the same vertical plane, and the end of the kerf is communicated with the mounting hole; the optical fiber temperature measurement sensor is laid at the bottom of the kerf and in the mounting hole, the optical fiber temperature measurement sensor in the mounting hole is sleeved with a sealing ring, and the outer side end of the optical fiber temperature measurement sensor is locked in the mounting hole through a fastening nut; and a sealing material is filled in the kerf after the optical fiber temperature measurement sensor is laid. According to the invention, the temperature of the crystallizer copper plate can be dynamically detected in real time with high precision and high density, so that the initial solidification process of molten steel in the crystallizer and the flowing state of the molten steel are indirectly reflected, and conditions are created for optimizing the flow field of the slab continuous casting crystallizer and improving the quality of continuous casting products in combination with an electromagnetic flow control technology.

Description

Technical Field

[0001] The invention relates to continuous casting technology, and in particular to a slab continuous casting crystallizer flow field detection device and method. Background Art

[0002] The crystallizer is the heart of continuous casting. The flow state of molten steel in the crystallizer directly determines the final quality of the continuous casting product. In the production process, technical means are usually required to optimize the flow field of molten steel in the crystallizer to avoid slag rolls, liquid level fluctuations, and excessive impact of steel flow. Additional technical means are required to optimize the flow field of the crystallizer in production. The methods for optimizing the flow field of the crystallizer can usually be divided into two types: passive and active.

[0003] The passive type is mainly achieved through optimization of the immersed nozzle structure, inclination angle, etc.

[0004] The active type is mainly achieved by applying an external field, such as electromagnetic swirl water inlet, crystallizer electromagnetic stirring and electromagnetic braking.

[0005] Electromagnetic stirring drives the molten steel to rotate through electromagnetic force. The rotating molten steel has a flushing effect at the solidification front, thereby taking away inclusions and bubbles at the solidification front and promoting their floating and removal, ultimately improving the surface quality of the continuous casting billet.

[0006] Electromagnetic braking is a technology that applies a static magnetic field to the flowing molten steel and reduces its absolute flow velocity through the induced Lorentz force. When the static magnetic field acts below the nozzle, it can reduce the impact depth of the molten steel, which is conducive to the floating of inclusions and bubbles; when the static magnetic field acts on the meniscus, it can stabilize the liquid level fluctuation and reduce slag roll-up.

[0007] In the actual production process of slab continuous casting, the flow field in the crystallizer is extremely complex and constantly changes during the entire continuous casting production process. For example, the phenomenon of bias flow is often prone to occur during the continuous casting process, that is, the flow rate of the molten steel on both sides of the water inlet is quite different, resulting in an asymmetric phenomenon in which the flow rate on one side is faster and the flow rate on the other side is slower. Similarly, local excessive flow rate or eddy currents are also prone to occur near the meniscus. Electromagnetic stirring or electromagnetic braking, as a technical means to optimize and control the flow field of the crystallizer, has been widely used in actual production. However, in the actual production process, due to the high temperature characteristics of molten steel, it is difficult to detect the actual flow state of molten steel online, which brings great difficulties to the control of the flow field. The existing continuous casting machine crystallizer copper plate usually uses a limited number of thermocouples for temperature measurement. Although it can provide basic information on the initial solidification of molten steel and is used for continuous casting auxiliary processes such as steel leakage prediction, it is difficult to use it for the analysis and inference of the flow state of molten steel in the crystallizer. In recent years, thanks to the development of optical fiber temperature measurement technology, using the characteristics of fast, timely and high precision of optical fiber temperature measurement, this technology has also begun to be applied to the temperature measurement of the continuous casting crystallizer copper plate.

[0008] Chinese patents CN102089095A and CN112935213A respectively disclose a method of encapsulating optical fiber on a crystallizer copper plate, that is, cutting a slit on the crystallizer copper plate and placing the optical fiber at the bottom of the slit. The main problem of this method is that the crystallizer needs to be cooled by high-pressure cooling water, and high-pressure water can easily enter the slit after cutting, which affects the temperature measurement accuracy on the one hand, and easily causes water leakage in serious cases, which brings safety hazards.

[0009] Chinese patent CN107614152A proposes another method of encapsulating optical fiber on the copper plate of the crystallizer, that is, by drilling a hole in the copper plate of the crystallizer, inserting the optical fiber sensor and fixing it. The main problem of this method is that when drilling a hole in the crystallizer, if the hole diameter is too small, it is difficult to drill deep, affecting the temperature measurement range; if the hole diameter is too large, it will affect the heat transfer of the crystallizer itself.

[0010] The surface quality of the continuous casting billet is related to the purity of the molten steel, pouring temperature, billet drawing speed, cooling intensity, argon flow rate, etc., and the use of electromagnetic stirring / electromagnetic braking is crucial. An important function of using electromagnetic stirring / electromagnetic braking in the crystallizer is to change the flow rate and flow direction of the molten steel through the action of electromagnetic force, improve the uniformity of the solidified billet shell, reduce the probability of inclusions and bubbles being captured at the solidification front, promote the floating of inclusions and bubbles, and ultimately improve the surface quality. At the same time, through the action of electromagnetic force, the temperature of the molten steel becomes more uniform, and the equiaxed crystal ratio can be appropriately increased. Therefore, electromagnetic flow control technology has become a key core technology for high-quality and high-efficiency production of slab continuous casting billets.

[0011] During the slab continuous casting production process, molten steel enters the continuous casting crystallizer through an immersed nozzle. After impacting the narrow surface of the crystallizer, the molten steel flows in the upper and lower directions, respectively, thus forming two upper and lower circulations in the crystallizer. The size of these two circulations, the local flow rate, etc. have a crucial impact on the quality of the slab. Generally speaking, a stable and moderate flow velocity distribution is beneficial to production, but it is difficult to detect and control in real time during the actual production process, especially during the casting process, when biased flow often occurs. To this end, according to the above-mentioned characteristics of the crystallizer flow field, different forms of electromagnetic flow control technology can be used in different areas, and the electromagnetic force can be used to artificially control the flow velocity of the molten steel, thereby forming an ideal flow field distribution.

[0012] However, due to the high temperature characteristics of molten steel, there is currently no technical means to directly detect the flow state of molten steel in real time online. Summary of the invention

[0013] The purpose of this aspect is to provide a slab continuous casting crystallizer flow field detection device and method, which can dynamically detect the temperature of the crystallizer copper plate with high precision and high density in real time, thereby indirectly reflecting the initial solidification process of molten steel and the flow state of molten steel in the crystallizer, and combining with electromagnetic flow control technology, ultimately creating conditions for optimizing the slab continuous casting crystallizer flow field and improving the quality of continuous casting products.

[0014] To achieve the above object, the technical solution of the present invention is:

[0015] A slab continuous casting crystallizer flow field detection device, comprising:

[0016] A mounting hole is provided on the end face of the copper plate of the crystallizer along the direction of continuous casting. The axis of the mounting hole is parallel to the working surface of the copper plate of the crystallizer, and the distance from the working surface of the copper plate of the crystallizer is ≥10mm, the hole diameter is ≤10mm, and the hole depth exceeds the position of the high-pressure cooling water sealing ring of the copper plate of the crystallizer; the mounting hole and the original cooling water tank on the crystallizer are staggered;

[0017] A slit is provided on the working surface of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, the center line of the slit and the axis of the mounting hole are located in the same vertical plane, and the end of the slit is connected and penetrated with the mounting hole; the slit depth is: the bottom of the slit is located above the radial bottom end of the mounting hole;

[0018] An optical fiber temperature sensor is laid at the bottom of the slit and in the mounting hole. A sealing ring is disposed on the outer cover of the optical fiber temperature sensor in the mounting hole. The inner end of the sealing ring abuts against the end of the slit. The sealing ring and the optical fiber temperature sensor are tightly connected to prevent water leakage. The outer end of the sealing ring is locked in the mounting hole by a fastening nut.

[0019] The sealing material is filled in the cut seam after the optical fiber temperature sensor is laid.

[0020] Preferably, the slit width is 1 to 3 mm.

[0021] Preferably, the sealing material is the same material as the crystallizer copper plate.

[0022] Preferably, the diameter of the optical fiber temperature sensor is ≤2 mm.

[0023] Preferably, the thickness of the crystallizer copper plate is between 25 mm and 45 mm.

[0024] The method for installing the slab continuous casting crystallizer flow field detection device of the present invention comprises the following steps:

[0025] 1) Drill a mounting hole on the end face of the copper plate of the crystallizer along the direction of continuous casting. The axis of the mounting hole is parallel to the working surface of the copper plate of the crystallizer, and the distance from the working surface of the copper plate of the crystallizer is ≥10mm. The hole diameter

[0026] ≤10mm, the hole depth exceeds the position of the high-pressure cooling water sealing ring of the crystallizer copper plate; the installation hole and the original cooling water tank position on the crystallizer are staggered;

[0027] 2) cutting a slit on the working surface of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, wherein the center line of the slit and the axis line of the mounting hole are located in the same vertical plane, and the end of the slit is connected and penetrates the mounting hole;

[0028] 3) An optical fiber temperature sensor is installed at the bottom of the slit and in the installation hole. A sealing ring is provided on the outer cover of the optical fiber temperature sensor in the installation hole. The inner end of the sealing ring abuts against the end of the slit. The sealing ring and the optical fiber temperature sensor are tightly connected to prevent water leakage. The outer end of the sealing ring is locked in the installation hole by a fastening nut.

[0029] 4) After the optical fiber temperature sensor is laid and installed, the cut seam is sealed with the same material as the crystallizer copper plate, thus completing the installation of the optical fiber temperature sensor on the crystallizer copper plate.

[0030] Preferably, the thickness of the crystallizer copper plate is 25 to 45 mm.

[0031] Preferably, the slit width is 1 to 3 mm.

[0032] In the process of continuous casting of steel slabs, high-temperature molten steel is cooled through a crystallizer and gradually solidified into a solid ingot. The continuous casting crystallizer is composed of four copper plates combined to form a rectangular solidification cavity, and the crystallizer copper plates are usually made of metal copper or copper alloy.

[0033] The existing method of installing optical fiber temperature sensors on crystallizers has technical difficulties such as water leakage or limited measurement range.

[0034] The present invention organically combines the advantages of two packaging methods, that is, fully utilizing the advantages of the hole installation method for easy sealing and the slit installation method for wide sensor detection range. On the one hand, by arranging the optical fiber sensor at the bottom of the slit and using sealing materials to make the sensor and the crystallizer copper plate in close contact, the detection accuracy is improved; at the same time, the length range of the sensor is not limited by the slit installation method, and the detection range is wider. On the other hand, after laying the optical fiber sensor in the hole machined on the end face of the crystallizer, mechanical structures such as sealing rings and fastening nuts can be used for sealing to prevent the crystallizer's high-pressure cooling water from leaking out. The above method effectively avoids the technical difficulties brought about by traditional installation methods.

[0035] Beneficial effects of the present invention:

[0036] Compared with traditional thermocouple temperature measurement technology, optical fiber temperature sensing technology has technical advantages such as high measurement accuracy, fast response, and dense number of temperature measurement points. In recent years, it has been industrially applied in the temperature measurement of continuous casting slab crystallizers. However, how to efficiently and stably package optical fiber temperature sensors has always been a technical problem.

[0037] The existing technology generally adopts the method of cutting or deep drilling the copper plate of the crystallizer, and then laying the optical fiber temperature sensor. The above method has problems such as high-pressure water leakage in the crystallizer affecting the temperature measurement accuracy, potential safety hazards, or high processing difficulty, which restricts the application of optical fiber temperature measurement technology in the steel industry.

[0038] Based on the specific characteristics of the continuous casting crystallizer and the working conditions of the continuous casting production, the present invention innovatively proposes a new method for installing an optical fiber temperature measuring sensor.

[0039] The present invention organically combines the advantages of two packaging methods, that is, fully utilizing the advantages of hole installation for easy sealing and slit installation for wide sensor detection range. On the one hand, by arranging the optical fiber sensor at the bottom of the slit and using sealing materials to make the sensor and the crystallizer copper plate in close contact, the detection accuracy is improved. At the same time, the length range of the sensor is not limited by the slit installation method, and the detection range is wide. On the other hand, after laying the optical fiber sensor in the hole processed on the end face of the crystallizer, mechanical structures such as sealing rings and fastening nuts can be used for sealing.

[0040] By utilizing the method of the present invention, problems such as cooling water leakage and copper plate processing difficulties that are prone to occur during the packaging of the optical fiber temperature sensor on the copper plate of the crystallizer can be effectively avoided, making it possible to perform high-precision, high-density, and high-response speed temperature detection of the copper plate of the slab continuous casting crystallizer and real-time detection of the flow field state of the molten steel in the crystallizer, and creating conditions for the dynamic control of the crystallizer flow field, which is conducive to the production of high-quality continuous casting billets. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A three-dimensional diagram of an embodiment of the present invention;

[0042] Figure 2 A side view of an embodiment of the present invention;

[0043] Figure 3 A front view of an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the structure of the slits and mounting holes on the copper plate of the crystallizer in an embodiment of the present invention;

[0045] Figure 5 This is an embodiment of the present invention. DETAILED DESCRIPTION

[0046] See also Figure 1 to Figure 5 The slab continuous casting crystallizer flow field detection device of the present invention comprises:

[0047] A mounting hole 101 is provided on the end surface of the crystallizer copper plate 1 along the continuous casting direction, the axis of the mounting hole 101 is parallel to the working surface 102 of the crystallizer copper plate 1, and the distance from the working surface 102 of the crystallizer copper plate 1 is ≥10mm, the hole diameter is ≤10mm, and the hole depth exceeds the position of the high-pressure cooling water sealing ring 6 of the crystallizer copper plate 1; the mounting hole and the original cooling water tank position on the 101 crystallizer are staggered;

[0048] A slit 103 is provided on the working surface 102 of the crystallizer copper plate 1 along the thickness direction of the crystallizer copper plate, the center line of the slit 103 and the axis of the mounting hole 101 are located in the same vertical plane, and the end of the slit 103 is connected and penetrated with the mounting hole 101; the depth of the slit 103 is: the bottom of the slit 103 is located above the radial bottom end of the mounting hole 101;

[0049] An optical fiber temperature sensor 2 is laid at the bottom of the slit 103 and in the mounting hole 101. A sealing ring 3 is arranged outside the optical fiber temperature sensor 2 in the mounting hole 101. The inner end of the sealing ring 3 abuts against the end of the slit 103. The sealing ring 3 and the optical fiber temperature sensor 2 are tightly connected to prevent water leakage. The outer end of the sealing ring 3 is locked in the mounting hole 101 by a fastening nut 4.

[0050] After the optical fiber temperature sensor 2 is laid, the sealing material 5 is filled in the cut slit 103 .

[0051] Preferably, the width of the slit 103 is 1 to 3 mm.

[0052] Preferably, the sealing material 5 is made of the same material as the copper plate of the crystallizer.

[0053] Preferably, the diameter of the optical fiber temperature sensor is ≤2 mm.

[0054] Preferably, the thickness of the crystallizer copper plate is between 25 mm and 45 mm.

[0055] The method for installing the slab continuous casting crystallizer flow field detection device of the present invention comprises the following steps:

[0056] 1) Drill a mounting hole 101 on the end face of the crystallizer copper plate 1 along the continuous casting direction, the axis of the mounting hole 101 is parallel to the working surface 102 of the crystallizer copper plate, and the distance from the working surface 102 of the crystallizer copper plate is ≥10mm, the hole diameter is ≤10mm, and the hole depth exceeds the position of the high-pressure cooling water sealing ring of the crystallizer copper plate 1; the mounting hole 101 is staggered from the original cooling water tank on the crystallizer;

[0057] 2) A slit is cut on the working surface 102 of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, the center line of the slit 103 and the mounting hole 101 are located on the same vertical plane, and the end of the slit 103 is connected and penetrates the mounting hole 101; Figure 4 As shown;

[0058] 3) An optical fiber temperature sensor 2 is installed at the bottom of the slit 103 and in the mounting hole 101. A sealing ring 3 is arranged outside the optical fiber temperature sensor 2 in the mounting hole 101. The inner end of the sealing ring 3 abuts against the end of the slit 103. The sealing ring 3 and the optical fiber temperature sensor 2 are tightly connected to prevent water leakage. The outer end of the sealing ring 3 is locked in the mounting hole by a fastening nut 4. Figure 5 As shown;

[0059] 4) After the optical fiber temperature sensor is laid and installed, the cut seam is sealed with the same material as the crystallizer copper plate, thus completing the installation of the optical fiber temperature sensor on the crystallizer copper plate.

[0060] Preferably, the thickness of the crystallizer copper plate is 25 to 45 mm.

[0061] Preferably, the slit width is 1 to 3 mm.

[0062] Example

[0063] The slab continuous casting crystallizer is composed of 4 copper plates, of which the wide copper plate has the specifications of 40mm thick, 900mm high and 1930mm wide. During the production process, the molten steel is cooled and solidified in the rectangular cavity formed by the 4 crystallizer copper plates. The heat of the molten steel is mainly taken away by the high-pressure cooling water behind the crystallizer copper plates, that is, the heat is mainly conducted along the thickness direction. The casting direction is the height direction of the crystallizer copper plate. In order to realize real-time dynamic monitoring of the initial solidification process of continuous casting, it is necessary to perform high-precision and high-density dynamic detection of the temperature of the crystallizer copper plate. To this end, the method designed according to the present invention is carried out by the following steps to mechanically process the crystallizer copper plate and complete the packaging of the optical fiber temperature sensor.

[0064] First, drill a mounting hole on the end face of the crystallizer copper plate along the height direction of the crystallizer copper plate. The center of the mounting hole is 21mm away from the working surface of the crystallizer copper plate. The diameter of the mounting hole is 5mm. The mounting hole is 100mm deep and exceeds the position of the copper plate sealing ring. The center line of the mounting hole is parallel to the surface of the crystallizer copper plate and staggered with the original cooling water tank position on the crystallizer.

[0065] Secondly, a slit is cut along the thickness direction of the copper plate, with a slit width of 1.5 mm and a depth of 23.5 mm, and the center line of the slit and the axis of the mounting hole are located in the same vertical plane; the slit length is 800 mm, and the end of the slit is connected and penetrated with the mounting hole, which is convenient for laying and installing the optical fiber temperature sensor;

[0066] Finally, a fiber optic temperature sensor with a diameter of 1 mm is laid and installed at the bottom of the slit; a sealing ring with an outer diameter of 5 mm is arranged on the outside of the middle section of the fiber optic temperature sensor, and the sealing ring is tightly connected to the fiber optic temperature sensor without water leakage. The fiber optic temperature sensor with a sealing ring is fixed to the crystallizer copper plate by a fastening nut. After the fiber optic temperature sensor is laid and installed, the slit is sealed with the same material as the crystallizer copper plate to complete the installation of the fiber optic temperature sensor on the crystallizer copper plate.

[0067] According to the process requirements, the above method can be used to install one or more optical fiber temperature sensors on a crystallizer copper plate to perform high-precision, high-density real-time dynamic detection of the crystallizer copper plate temperature.

[0068] With the continuous improvement of users' requirements for the quality of steel products and the inherent requirements of enterprises for efficient production, higher requirements are put forward for the control of the flow field of the slab crystallizer. The crystallizer copper plate designed by the present invention is not difficult to process and manufacture, the laying and installation method of the optical fiber temperature sensor is highly feasible, and the equipment is easy to install and replace, and it is expected to have a wide range of application prospects.

Claims

1. A slab continuous casting crystallizer flow field detection device, characterized in that: include: A mounting hole is provided on the end face of the copper plate of the crystallizer along the direction of continuous casting. The axis of the mounting hole is parallel to the working surface of the copper plate of the crystallizer, and the distance from the working surface of the copper plate of the crystallizer is ≥10mm, the hole diameter is ≤10mm, and the hole depth exceeds the position of the high-pressure cooling water sealing ring of the copper plate of the crystallizer; the mounting hole and the original cooling water tank on the crystallizer are staggered; A slit is provided on the working surface of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, the center line of the slit and the axis of the mounting hole are located in the same vertical plane, and the end of the slit is connected and penetrated with the mounting hole; the slit depth is: the bottom of the slit is located above the radial bottom end of the mounting hole; An optical fiber temperature sensor is laid at the bottom of the slit and in the mounting hole. A sealing ring is disposed on the outer cover of the optical fiber temperature sensor in the mounting hole. The inner end of the sealing ring abuts against the end of the slit. The sealing ring and the optical fiber temperature sensor are tightly connected to prevent water leakage. The outer end of the sealing ring is locked in the mounting hole by a fastening nut. The sealing material is filled in the cut seam after the optical fiber temperature sensor is laid.

2. The slab continuous casting mold flow field detection device according to claim 1, characterized in that: The slit width is 1 to 3 mm.

3. The slab continuous casting mold flow field detection device according to claim 1, characterized in that: The sealing material is the same material as the copper plate of the crystallizer.

4. The slab continuous casting mold flow field detection device according to claim 1, characterized in that: The diameter of the optical fiber temperature sensor is ≤2mm.

5. The slab continuous casting mold flow field detection device according to claim 1, characterized in that: The thickness of the crystallizer copper plate is between 25 mm and 45 mm.

6. A method for installing a slab continuous casting crystallizer flow field detection device, characterized in that: The steps include: 1) Drill a mounting hole on the end face of the copper plate of the crystallizer along the direction of continuous casting. The axis of the mounting hole is parallel to the working surface of the copper plate of the crystallizer, and the distance from the working surface of the copper plate of the crystallizer is ≥10mm. The hole diameter is ≤10mm, and the hole depth exceeds the position of the high-pressure cooling water sealing ring of the copper plate of the crystallizer; the mounting hole and the original cooling water tank on the crystallizer are staggered; 2) cutting a slit on the working surface of the crystallizer copper plate along the thickness direction of the crystallizer copper plate, wherein the center line of the slit and the axis line of the mounting hole are located in the same vertical plane, and the end of the slit is connected and penetrates the mounting hole; 3) An optical fiber temperature sensor is installed at the bottom of the slit and in the installation hole. A sealing ring is provided on the outer cover of the optical fiber temperature sensor in the installation hole. The inner end of the sealing ring abuts against the end of the slit. The sealing ring and the optical fiber temperature sensor are tightly connected to prevent water leakage. The outer end of the sealing ring is locked in the installation hole by a fastening nut. 4) After the optical fiber temperature sensor is laid and installed, the cut seam is sealed with the same material as the crystallizer copper plate, thus completing the installation of the optical fiber temperature sensor on the crystallizer copper plate.

7. The slab continuous casting mold flow field detection method according to claim 6, characterized in that: The thickness of the crystallizer copper plate is 25-45 mm.

8. The slab continuous casting mold flow field detection method according to claim 6, characterized in that: The slit width is 1 to 3 mm.

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