Method for capping the tail billet of high manganese steel continuous casting
By reducing casting speed in stages, adjusting slag removal and cooling water flow, and using cooling components, the problem of billet bulging during the tail exit of high manganese steel continuous casting was solved, improving production efficiency and billet quality, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUNAN VALIN LIANYUAN IRON & STEEL CO LTD
- Filing Date
- 2025-07-31
- Publication Date
- 2026-06-30
AI Technical Summary
High manganese steel continuously cast billets are prone to bulging during the tailing process, which leads to increased production costs and uncontrolled billet quality.
By adopting a phased reduction in casting speed, combined with slag removal from the crystallizer liquid surface, adjustment of cooling water flow rate, and the use of cooling components, the stable solidification and sealing of the tail billet are ensured, and internal stress concentration and crack formation are avoided.
This effectively reduced the bulging of tail billets, improved production efficiency and billet quality, reduced production costs, and ensured the steel yield and stability of the continuous casting process for high-manganese steel.
Smart Images
Figure CN121131702B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of the metallurgical industry, and in particular relates to a method for capping the tail billet of high manganese steel continuous casting. Background Technology
[0002] High manganese steel is increasingly widely used due to its excellent wear resistance, low-temperature mechanical properties, and non-magnetic nature. For example, MN13 wear-resistant steel, MN24 ultra-low temperature pressure vessel steel, and 20MN23ALV non-magnetic steel are typical examples of high manganese steel. In recent years, with the continuous development of continuous casting technology, replacing ingot casting with continuous casting has become the development direction of high manganese steel production technology. However, due to the relatively low thermal conductivity and high coefficient of linear expansion of high manganese steel, the initial pouring stage, the stable pouring stage, and the shutdown stage constitute the core production links in the continuous casting process. Among them, the initial pouring and shutdown stages are unsteady-state processes, and these two stages are extremely prone to production accidents, which also lead to the risk of uncontrolled slab quality. In particular, during the shutdown operation, poor capping of the tail billet can cause it to bulge out, affecting the output of cast billets and increasing production costs.
[0003] Currently, long-duration, low-speed casting (≤0.3 m / min) operation is commonly used for capping. This leads to bulging at the tail end of the slab during exiting the casting, causing transverse cracks on the slab surface. Furthermore, the tail end of the slab exhibits delamination defects, significantly reducing yield and economic efficiency. Therefore, this invention provides a method for capping the tail end of a high-manganese steel continuous casting slab. Summary of the Invention
[0004] The main objective of this invention is to provide a method for sealing the tail of a high-manganese steel continuous casting billet, which aims to solve the technical problem in the prior art where the tail of the billet expands during the tailing process, increasing production costs.
[0005] To achieve the above objectives, the present invention provides a method for capping the tail of a high-manganese steel continuous casting billet, comprising the following steps:
[0006] Before stopping pouring, reduce the casting speed from the reference speed to the first speed and keep the first speed stable.
[0007] Reduce the first pulling speed to the second pulling speed, and after the second pulling speed stabilizes, perform the slag removal operation on the liquid surface of the crystallizer.
[0008] The light pressure function is canceled, and the cooling water flow rate of the wide face of the crystallizer is reduced from the first cooling water flow rate to the second cooling water flow rate. At the same time, the cooling water volume of the second cooling zone is locked at a constant value.
[0009] After reducing the second pulling speed to the third pulling speed, remove the immersion nozzle and add a cooling element to the crystallizer.
[0010] After the tail of the slab is removed from the crystallizer, the recessed area formed at the tail of the slab is inspected.
[0011] After the tail billet is capped, the third drawing speed is gradually increased to the target drawing speed until the tail billet is completely drawn out of the fan-shaped segment.
[0012] The target pulling speed is 1.0 to 1.2 m / min.
[0013] According to the embodiments of this application, the first pulling speed is 0.7 to 0.8 m / min, the second pulling speed is 0.5 to 0.6 m / min, and the third pulling speed is 0.3 to 0.4 m / min.
[0014] According to an embodiment of this application, the step of progressively increasing the third pulling speed to the target pulling speed includes:
[0015] Increase the third pulling speed to 0.6-0.7 m / min and maintain it for 90-120 s, then increase it to the target pulling speed.
[0016] The target pulling speed is 1.0 to 1.2 m / min.
[0017] According to the embodiments of this application, the first cooling water flow rate is 4000-4200 L / min, and the second cooling water flow rate is 3400-3600 L / min.
[0018] According to the embodiments of this application, in the step of locking the cooling water volume of the secondary cooling zone to a constant value, the thickness of the tail billet shell obtained is 25-30 mm.
[0019] According to the embodiments of this application, the cooling component is a rigid structure, its welding width is 18-22cm smaller than the width of the crystallizer, its thickness is 3-7cm smaller than the thickness of the crystallizer, and the amount of cooling component added is 1.
[0020] According to an embodiment of this application, the step of detecting the recessed area formed at the tail of the slab includes detecting the sealing of the recessed area and the solidification thickness of the slab shell.
[0021] The solidification thickness of the blank shell is 25-30 mm.
[0022] The present invention also provides a high-manganese steel obtained by the above-described capping method, wherein the high-manganese steel comprises, by mass percentage: C 0.9-1.1%, Si 0.4-0.5%, Mn 12-14%, with the balance being Fe and unavoidable impurities.
[0023] According to the embodiments of this application, the high manganese steel has a yield strength of 400-700 MPa, a tensile strength of 800-1000 MPa, and an elongation of 20-30%.
[0024] According to the embodiments of this application, the high manganese steel, after being cold-worked and hardened by 30-50%, has a surface hardness ≥500HBW.
[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0026] The aforementioned method for sealing the tail slab in continuous casting of high-manganese steel effectively alleviates stress concentration within the slab caused by sudden speed changes and reduces the crack incidence by gradually reducing the casting speed and maintaining phased stability. During the second speed stabilization stage, slag removal is performed to precisely remove slag and inclusions from the crystallizer surface, reducing surface defects. The light reduction function is eliminated, and the cooling water flow rate across the wide face of the crystallizer is reduced in stages to avoid excessive cooling of the crystallizer inner wall, reducing thermal stress damage. Maintaining a constant cooling water flow rate in the secondary cooling zone ensures uniform temperature field in the slab, accelerates tail slab solidification, and allows for rapid formation of a shell of a certain thickness, while avoiding prolonged low-speed casting at the tail end, which could lead to cracking. It also prevents the tail slab from becoming too hard and damaging the fan-shaped section, ensuring tail slab quality, improving the continuous casting process efficiency, and increasing the steel yield of high-manganese steel. In the third speed stage, the submerged entry nozzle is removed and a cooling component is added to eliminate the risk of nozzle blockage, while simultaneously accelerating tail-end solidification and forming a sealed recessed area to prevent steel leakage. The cooling components effectively seal and withstand the static pressure of the remaining molten steel, causing the liquid level in the crystallizer to drop to the target position. The stepped increase in the tail billet drawing speed avoids shear stress on the tail billet shell, reducing the occurrence of internal cracks. Through the above-mentioned step-by-step adjustment of drawing speed, cooling water flow rate, and process steps, slab defects can be effectively reduced, the quality of the crystallizer and the cast billet can be improved, the cooling effect can be optimized, tail billet defects can be reduced, and production efficiency and stability can be improved. This invention has simple steps, is easy to operate, and has low production costs. It can quickly complete the capping operation when the high-manganese steel tail billet exits, effectively solving the problem of tail billet bulging. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0028] Figure 1 A schematic diagram showing the relationship between the continuous casting speed and the billet removal time after the "first-strand molten steel" is stopped;
[0029] Figure 2 A schematic diagram showing the relationship between the continuous casting speed and the billet pulling time after the "2nd flow of molten steel" is stopped.
[0030] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0032] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0033] In existing technologies, the continuous casting process involves three stages: start-up casting, stable casting, and stop casting. The start-up and stop casting stages, being non-steady-state processes, are highly prone to production accidents and pose a risk of uncontrolled slab quality. Therefore, more and more researchers are focusing on the start-up and stop-stop casting operations, particularly the stop casting operation. Poor capping of the tail slab can lead to severe slab overflow at the tail exit, potentially causing the fan-shaped section to be welded shut, impacting output and increasing production costs. To address these problems in the non-steady-state continuous casting process, this invention provides a method for capping the tail slab of high-manganese steel continuous casting, aiming to solve the technical problem of slab overflow and increased production costs during the tail exit process in existing technologies.
[0034] To achieve the above objectives, the present invention provides a method for capping the tail of a high-manganese steel continuous casting billet, comprising the following steps:
[0035] Before stopping pouring, reduce the casting speed from the reference speed to the first speed and keep the first speed stable.
[0036] In some embodiments, reducing the casting speed from the reference speed to the first speed before stopping casting can reduce internal defects in the slab caused by excessively rapid speed changes. Maintaining a stable first speed helps ensure smooth flow of molten steel within the crystallizer, reduces surface fluctuations, and improves crystallization quality. It also helps reduce thermal stress and the risk of cracking on the inner wall of the crystallizer, thereby extending its service life.
[0037] Reduce the first pulling speed to the second pulling speed, and after the second pulling speed stabilizes, perform the slag removal operation on the liquid surface of the crystallizer.
[0038] In some embodiments, the first casting speed is reduced to a second casting speed, and after the second casting speed stabilizes, a slag removal operation is performed on the crystallizer liquid surface. Removing slag after the second casting speed has stabilized helps maintain a stable liquid level in the crystallizer, reducing the impact of liquid level fluctuations on the crystallization process. The slag removal operation effectively removes scum and inclusions from the crystallizer liquid surface, reducing the amount of inclusions entering the slab, significantly improving the slab surface quality, and reducing surface defects such as scratches and dents.
[0039] The light pressure function is canceled, and the cooling water flow rate of the wide face of the crystallizer is reduced from the first cooling water flow rate to the second cooling water flow rate. At the same time, the cooling water volume of the second cooling zone is locked at a constant value.
[0040] In some embodiments, reducing the cooling water flow rate across the wide face of the crystallizer can prevent excessive cooling and resulting in excessively low temperatures on the inner wall of the crystallizer, thereby reducing thermal stress and the risk of cracking on the inner wall. Simultaneously, locking the cooling water flow rate in the secondary cooling zone to a constant value ensures a stable cooling process for the slab in the secondary cooling zone, avoiding uneven slab temperature caused by fluctuations in cooling water flow. Precise control of the cooling water flow rate can improve the internal and surface quality of the cast slab and reduce defects caused by improper cooling.
[0041] In some embodiments, the secondary cooling water volume is locked according to the cross-section before the end of casting to accelerate the solidification of the tail billet, enabling it to quickly form a shell of a certain thickness. This also avoids excessively long low-speed casting time at the tail exit, which could lead to cracks. Simultaneously, (by locking the secondary cooling water volume in the crystallizer, reducing crystallizer cooling) it prevents the tail billet from becoming too hard and damaging the fan-shaped section, ensuring tail billet quality, improving the continuous casting process's operating rate, and increasing the high-manganese steel yield. This solves the problem in existing technologies where high-manganese steel is not directly tail-exited but is instead mixed with other steel grades before tail-exit, resulting in uncontrolled slab composition, scrap, and reduced steel yield.
[0042] After reducing the second pulling speed to the third pulling speed, remove the immersion nozzle and add a cooling element to the crystallizer.
[0043] In some embodiments, reducing the casting speed to a third casting speed helps ensure smooth solidification of the tail billet and reduces tail billet defects caused by excessive speed changes. Removing the submerged entry nozzle can avoid problems with poor molten steel flow caused by nozzle blockage and reduce downtime. Adding a cooling element can further optimize the cooling effect within the crystallizer and ensure the solidification quality of the slab tail.
[0044] In some embodiments, by employing a cooling element at the tail end, the remaining molten steel can be effectively sealed and subjected to static pressure, causing the liquid level in the crystallizer to drop to a set position.
[0045] In some embodiments, the cooling component is placed inside the crystallizer, and the cooling component melts into the center of the liquid phase at the tail of the billet in a timely manner, so as to achieve the purpose of rapid sealing of the billet tail.
[0046] After the tail of the slab is removed from the crystallizer, the recessed area formed at the tail of the slab is inspected.
[0047] In some embodiments, by detecting the recessed area, defects at the tail of the slab can be detected in a timely manner, which facilitates the adjustment of process parameters such as drawing speed and cooling water volume based on the detection results, so as to reduce the occurrence of tail slab defects.
[0048] After the tail billet is capped, the third drawing speed is gradually increased to the target drawing speed until the tail billet is completely drawn out of the fan-shaped segment.
[0049] The target pulling speed is 1.0 to 1.2 m / min.
[0050] In some embodiments, by progressively increasing the third drawing speed to the target drawing speed, stress concentration inside the slab caused by excessive speed changes can be avoided, reducing the generation of defects such as cracks. Maintaining a stable target drawing speed during the tail-end drawing process can ensure the quality of the tail-end, reduce tail-end defects caused by speed changes, improve production efficiency, and reduce downtime.
[0051] In some embodiments, before stopping the pouring, the speed is reduced to 0.6 m / min and the slag is scooped out to clean the liquid slag. The rod is turned off and the blind plate is opened. The light pressing is canceled, the water flow rate of the wide face of the crystallizer is reduced, the secondary cooling water is locked, the immersion nozzle is removed, and the cooling component is placed in. During the tailing process, the operation is not allowed to be stopped.
[0052] In some embodiments, by precisely controlling the casting speed, cooling water flow rate, and the addition of cooling components, the capping method ensures high-quality solidification of the tail billet, reduces tail billet defects, and improves production efficiency and stability. It avoids bulging at the tail of the slab during the tail-out process, reduces the excessively long low-speed casting time at the tail of the slab, prevents the tail billet from becoming too hard and damaging the fan-shaped section, ensures tail billet quality, improves the continuous casting process operating rate, and increases the yield of high-manganese steel.
[0053] The aforementioned method for sealing the tail slab in continuous casting of high-manganese steel effectively alleviates stress concentration within the slab caused by sudden speed changes and reduces the crack incidence by gradually reducing the casting speed and maintaining phased stability. During the second speed stabilization stage, slag removal is performed to precisely remove slag and inclusions from the crystallizer surface, reducing surface defects. The light reduction function is eliminated, and the cooling water flow rate across the wide face of the crystallizer is reduced in stages to avoid excessive cooling of the crystallizer inner wall, reducing thermal stress damage. Maintaining a constant cooling water flow rate in the secondary cooling zone ensures uniform temperature field in the slab, accelerates tail slab solidification, and allows for rapid formation of a shell of a certain thickness, while avoiding prolonged low-speed casting at the tail end, which could lead to cracking. It also prevents the tail slab from becoming too hard and damaging the fan-shaped section, ensuring tail slab quality, improving the continuous casting process efficiency, and increasing the steel yield of high-manganese steel. In the third speed stage, the submerged entry nozzle is removed and a cooling component is added to eliminate the risk of nozzle blockage, while simultaneously accelerating tail-end solidification and forming a sealed recessed area to prevent steel leakage. The cooling components effectively seal and withstand the static pressure of the remaining molten steel, causing the liquid level in the crystallizer to drop to the target position. The stepped increase in the tail billet drawing speed avoids shear stress on the tail billet shell, reducing the occurrence of internal cracks. Through the above-mentioned step-by-step adjustment of drawing speed, cooling water flow rate, and process steps, slab defects can be effectively reduced, the quality of the crystallizer and the cast billet can be improved, the cooling effect can be optimized, tail billet defects can be reduced, and production efficiency and stability can be improved. This invention has simple steps, is easy to operate, and has low production costs. It can quickly complete the capping operation when the high-manganese steel tail billet exits, effectively solving the problem of tail billet bulging.
[0054] In some embodiments, the first pulling speed is 0.7 to 0.8 m / min, the second pulling speed is 0.5 to 0.6 m / min, and the third pulling speed is 0.3 to 0.4 m / min.
[0055] In some embodiments, the first pulling speed is 0.8 m / min, the second pulling speed is 0.6 m / min, and the third pulling speed is 0.4 m / min.
[0056] In some embodiments, when the stopper rod of the continuous casting tumbler is opened, the water flows into the crystallizer through the nozzle. Before stopping casting, the casting speed is reduced from 0.9 m / min to 0.8 m / min and held for 2 minutes. Then, the casting speed is reduced to 0.6 m / min and stabilized for 1 minute before slag removal. The light pressing is canceled, the water level on the wide side of the crystallizer is reduced, and the secondary cooling water is locked. The casting speed is reduced to 0.4 m / min, the immersion nozzle is removed, and the cooling components are added. When the tail of the slab exits the crystallizer, a concave area is formed at the tail of the slab, and the tail slab is sealed. The speed is increased to 0.6 m / min and held for 90 seconds. Then, the speed is increased to 1.0 m / min before the fan-shaped section is drawn out.
[0057] In some embodiments, the step of progressively increasing the third pulling speed to the target pulling speed includes:
[0058] Increase the third pulling speed to 0.6-0.7 m / min and maintain it for 90-120 s, then increase it to the target pulling speed.
[0059] The target pulling speed is 1.0 to 1.2 m / min.
[0060] In some embodiments, the target drawing speed is 1.0 m / min. By gradually increasing the drawing speed to the target speed through a third drawing speed, stress concentration inside the slab caused by excessive speed changes can be avoided, reducing the generation of defects such as cracks.
[0061] In some embodiments, the first cooling water flow rate is 4000-4200 L / min, and the second cooling water flow rate is 3400-3600 L / min.
[0062] In some embodiments, the first cooling water flow rate is 4100 L / min and the second cooling water flow rate is 3500 L / min.
[0063] In some embodiments, regulating the cooling water flow rate can prevent excessive cooling that could lead to excessively low temperatures on the inner wall of the crystallizer, thereby reducing thermal stress and the risk of cracking on the inner wall of the crystallizer. By precisely regulating the cooling water flow rate, the internal and surface quality of the cast billet can be improved, and defects caused by improper cooling can be reduced.
[0064] In some embodiments, in the step of locking the cooling water volume of the secondary cooling zone to a constant value, the thickness of the tail billet shell is 25-30 mm.
[0065] In some embodiments, by optimizing the cooling water volume in the secondary cooling zone, it is possible to ensure that the shell thickness of the tail billet is between 25 and 30 mm, which helps the tail billet to solidify stably and reduces tail billet defects.
[0066] In some embodiments, the cooling element is a rigid structure, with a welding width 18-22 cm smaller than the width of the crystallizer and a thickness 3-7 cm smaller than the thickness of the crystallizer. The cooling element is added in units of one.
[0067] In some embodiments, the cooling component is a cooling steel plate, a rigid structure with a weld width less than 20cm of the crystallizer width and a thickness less than 5cm of the crystallizer thickness, and the cooling component is added in a quantity of 1.
[0068] In some embodiments, the cooling element is a rigid structure to ensure its stability in high-temperature environments. Adjusting the weld width and thickness to match the crystallizer dimensions allows the cooling element to fit the crystallizer while avoiding unnecessary thermal stress. Controlling the amount of cooling element added ensures effective cooling while preventing overcooling, thus improving the solidification quality at the tail end of the slab.
[0069] In some embodiments, the step of detecting the recessed area formed at the tail of the slab includes detecting the sealing of the recessed area and the solidification thickness of the slab shell.
[0070] The solidification thickness of the blank shell is 25-30 mm.
[0071] In some embodiments, detecting the recessed area formed at the tail of the slab includes: as the slab shell shrinks due to water cooling in the crystallizer, the tail of the slab will gradually solidify to form a recess. The operator needs to check that the recessed area at the tail does not cause molten steel to flow out and that the recessed area at the tail has a certain solidification thickness.
[0072] The present invention also provides a high-manganese steel obtained by the above-described capping method, wherein the high-manganese steel comprises, by mass percentage: C 0.9-1.1%, Si 0.4-0.5%, Mn 12-14%, with the balance being Fe and unavoidable impurities.
[0073] In some embodiments, the composition of high-manganese steel is controlled to ensure its high strength and good toughness, while the processing performance and wear resistance of the steel are improved by optimizing the carbon and silicon content. Through the synergistic optimization of composition and capping method, high-manganese steel exhibits excellent performance and quality, enhancing the overall process controllability and reliability.
[0074] In some embodiments, the high-manganese steel has a yield strength of 400–700 MPa, a tensile strength of 800–1000 MPa, and an elongation of 20–30%.
[0075] In some embodiments, the yield strength of high-manganese steel allows it to maintain good plastic deformation capacity even under high stress. Tensile strength ensures the strength and reliability of high-manganese steel under high-stress environments. The high-manganese steel possesses good plastic deformation capacity, enabling it to withstand significant deformation during processing and use without fracture.
[0076] In some embodiments, the high manganese steel, after undergoing 30-50% cold deformation work hardening, has a surface hardness ≥500HBW.
[0077] In some embodiments, the high surface hardness of high manganese steel improves its wear resistance and service life.
[0078] To further illustrate the present invention, the following examples are provided:
[0079] Example 1
[0080] A method for capping the tail of a high-manganese steel continuous casting billet includes the following steps:
[0081] When the stopper rod in the continuous casting tundish is opened, the billet flows into the crystallizer through the sprue. Before stopping casting, the casting speed of the continuous casting machine is reduced from 0.9 m / min to 0.8 m / min and maintained for 2 minutes. Then, the casting speed is reduced to 0.6 m / min and stabilized for 1 minute before slag removal. The light pressure is then removed, and the water flow rate on the wide side of the crystallizer is manually changed from 4100 L / min to 3500 L / min. The secondary cooling water is locked to accelerate the solidification of the tail billet and ensure the strength of the billet shell. The casting speed is then reduced to 0.4 m / min, the submersible nozzle is removed, and the cooling components are added. When the tail of the billet exits the crystallizer, a concave area is formed at the tail of the billet, indicating the end of the tail billet sealing. The casting speed is then increased to 0.6 m / min and maintained for 90 seconds. After that, the casting speed is increased to 1.0 m / min, and the fan-shaped section is drawn out.
[0082] Modern continuous casting machines are typically designed as multi-strand continuous casting machines, meaning that one crystallizer can simultaneously cast multiple slabs. For example, one crystallizer can simultaneously cast two slabs, referred to as "strand 1" and "strand 2". Figure 1 A schematic diagram showing the relationship between the continuous casting speed and the billet removal time after the "first-strand molten steel" is stopped; Figure 2 This is a schematic diagram showing the relationship between the continuous casting speed and the billet removal time after the "second flow of molten steel" is stopped. The composition of the "first flow of molten steel" and the "second flow of molten steel" is the same as the chemical composition of the high-manganese steel of this invention.
[0083] The aforementioned method for sealing the tail slab in continuous casting of high-manganese steel effectively alleviates stress concentration within the slab caused by sudden speed changes and reduces the crack incidence by gradually reducing the casting speed and maintaining phased stability. During the second speed stabilization stage, slag removal is performed to precisely remove slag and inclusions from the crystallizer surface, reducing surface defects. The light reduction function is eliminated, and the cooling water flow rate across the wide face of the crystallizer is reduced in stages to avoid excessive cooling of the crystallizer inner wall, reducing thermal stress damage. Maintaining a constant cooling water flow rate in the secondary cooling zone ensures uniform temperature field in the slab, accelerates tail slab solidification, and allows for rapid formation of a shell of a certain thickness, while avoiding prolonged low-speed casting at the tail end, which could lead to cracking. It also prevents the tail slab from becoming too hard and damaging the fan-shaped section, ensuring tail slab quality, improving the continuous casting process efficiency, and increasing the steel yield of high-manganese steel. In the third speed stage, the submerged entry nozzle is removed and a cooling component is added to eliminate the risk of nozzle blockage, while simultaneously accelerating tail-end solidification and forming a sealed recessed area to prevent steel leakage. The cooling components effectively seal and withstand the static pressure of the remaining molten steel, causing the liquid level in the crystallizer to drop to the target position. The stepped increase in the tail billet drawing speed avoids shear stress on the tail billet shell, reducing the occurrence of internal cracks. Through the above-mentioned step-by-step adjustment of drawing speed, cooling water flow rate, and process steps, slab defects can be effectively reduced, the quality of the crystallizer and the cast billet can be improved, the cooling effect can be optimized, tail billet defects can be reduced, and production efficiency and stability can be improved. This invention has simple steps, is easy to operate, and has low production costs. It can quickly complete the capping operation when the high-manganese steel tail billet exits, effectively solving the problem of tail billet bulging.
[0084] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A method for capping the tail of a high-manganese steel continuous casting billet, characterized in that, Includes the following steps: S1: Before stopping pouring, reduce the casting speed from the reference casting speed to the first casting speed and keep the first casting speed stable; S2: Reduce the first pulling speed to the second pulling speed, and after the second pulling speed is running stably, perform the slag removal operation on the liquid surface of the crystallizer; S3: Cancel the light pressure function, reduce the cooling water flow rate of the wide surface of the crystallizer from the first cooling water flow rate to the second cooling water flow rate, and lock the cooling water volume of the second cooling zone to a constant value. S4: After reducing the second pulling speed to the third pulling speed, remove the immersion nozzle and add a cooling component to the crystallizer; S5: After the tail of the slab is removed from the crystallizer, detect the recessed area formed at the tail of the slab; S6: After the tail billet is capped, the third drawing speed is increased stepwise to the target drawing speed until the tail billet is completely drawn out of the fan-shaped segment. The target pulling speed is 1.0 ~ 1.2 m / min; The first pulling speed is 0.7~0.8 m / min, the second pulling speed is 0.5~0.6 m / min, and the third pulling speed is 0.3~0.4 m / min; The step of gradually increasing the third pulling speed to the target pulling speed includes: Increase the third pulling speed to 0.6~0.7m / min and maintain it for 90~120s, then increase it to the target pulling speed; The step of detecting the recessed area formed at the tail of the slab includes detecting the sealing of the recessed area and the solidification thickness of the slab shell. The solidification thickness of the blank shell is 25~30mm.
2. The method for capping the high-manganese steel continuous casting tail billet according to claim 1, characterized in that, The first cooling water flow rate is 4000~4200 L / min, and the second cooling water flow rate is 3400~3600 L / min.
3. The method for capping the high-manganese steel continuous casting tail billet according to claim 1, characterized in that, In the step of locking the cooling water volume of the secondary cooling zone to a constant value, the thickness of the tail billet shell is 25~30mm.
4. The method for capping the high-manganese steel continuous casting tail billet according to claim 1, characterized in that, The cooling component is a rigid structure, with a welding width 18-22cm smaller than the width of the crystallizer and a thickness 3-7cm smaller than the thickness of the crystallizer. One cooling component is added.
5. A high-manganese steel produced by the capping method according to any one of claims 1 to 4, characterized in that, The high-manganese steel comprises, by mass percentage: C 0.9~1.1%, Si 0.4~0.5%, Mn 12~14%, with the balance being Fe and unavoidable impurities.
6. The high-manganese steel according to claim 5, characterized in that, The high-manganese steel has a yield strength of 400-700 MPa, a tensile strength of 800-1000 MPa, and an elongation of 20-30%.
7. The high-manganese steel according to claim 5, characterized in that, The high-manganese steel, after undergoing 30-50% cold deformation work hardening, has a surface hardness ≥500HBW.