Top sealing method for high manganese steel continuous casting tail blank

Abstract

The invention provides a top sealing method for a high manganese steel continuous casting tail billet, which comprises the following steps of: before stopping casting, reducing the billet pulling speed from a reference pulling speed to a first pulling speed, and keeping the first pulling speed stable; reducing the first pulling speed to a second pulling speed, and after the second pulling speed stably runs, carrying out slag fishing operation on the liquid level of the crystallizer; a soft reduction function is cancelled, the cooling water flow of the wide surface of the crystallizer is reduced from the first cooling water flow to the second cooling water flow, and meanwhile the cooling water flow of a secondary cooling area is locked to be a constant value; after the second pulling speed is reduced to a third pulling speed, the submersed nozzle is removed, and a cooling piece is added into the crystallizer; after the tail of the plate blank is moved out of the crystallizer, a sunken area formed at the tail of the plate blank is detected; after top sealing of the tail blank is completed, the third pulling speed is increased to the target pulling speed in a stepped mode till the tail blank is completely pulled out of the fan-shaped section; wherein the target pulling speed ranges from 1.0 m / min to 1.2 m / min. The method is simple in step, convenient to operate and low in production cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metallurgical industry, and particularly relates to a method for capping a high manganese steel continuous casting tail blank. BACKGROUND

[0002] High manganese steel is widely used in many fields due to its good wear resistance, low temperature mechanical properties and non-magnetic properties. For example, MN13 wear-resistant steel, MN24 ultra-low temperature pressure vessel steel and 20MN23ALV non-magnetic steel are all typical high manganese steels. In recent years, with the continuous development of continuous casting process, the continuous casting process has replaced the mold casting process and become the development direction of high manganese steel production technology. However, due to the low thermal conductivity and high linear expansion coefficient of high manganese steel, the start-up stage, the stable pouring stage and the stop pouring stage are the core production links in the production process. The start-up stage and the stop pouring stage are non-steady state processes, and production accidents are prone to occur in these two stages, which will also lead to uncontrollable risks of slab quality. Especially in the stop pouring operation process, the tail blank will be over-expanded if the tail blank capping is not good, which will affect the yield of the cast blank and increase the production cost.

[0003] At present, long-time low-pulling-speed capping (pulling speed ≤ 0.3 m / min) is generally used, and the tail of the slab will over-expand during the tailing-out process, the surface of the cast blank is prone to transverse cracks, and the tail of the cast blank has a layered defect area, which significantly reduces the yield and economic benefits. Based on this, the present application provides a method for capping a high manganese steel continuous casting tail blank. SUMMARY

[0004] The main purpose of the present application is to provide a method for capping a high manganese steel continuous casting tail blank, which aims to solve the technical problems of the existing technology that the tail of the slab over-expands during the tailing-out process and increases the production cost.

[0005] To achieve the above-mentioned purpose, the present application provides a method for capping a high manganese steel continuous casting tail blank, which comprises the following steps:

[0006] Before stopping pouring, the blank pulling speed is reduced from the reference pulling speed to the first pulling speed, and the first pulling speed is kept stable.

[0007] The first pulling speed is reduced to the second pulling speed, and after the second pulling speed is stably operated, the crystallizer liquid level is operated.

[0008] The light pressing function is cancelled, the crystallizer wide surface cooling water flow is reduced from the first cooling water flow to the second cooling water flow, and the cooling water flow of the secondary cooling zone is locked as a constant value.

[0009] After the second pulling speed is reduced to the third pulling speed, the submerged entry nozzle is removed, and a cooling piece is added to the crystallizer.

[0010] When the slab tail moves out of the crystallizer, the recess area formed by the slab tail is detected.

[0011] After the tail slab is capped, the third pulling speed is stepped up to the target pulling speed until the tail slab is completely pulled out of the fan-shaped section.

[0012] The target pulling speed is 1.0-1.2 m / min.

[0013] According to the embodiments of the present application, 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.

[0014] According to the embodiments of the present application, the step of stepping up the third pulling speed to the target pulling speed comprises:

[0015] The third pulling speed is increased to 0.6-0.7 m / min and maintained for 90-120 s, and then increased to the target pulling speed.

[0016] The target pulling speed is 1.0-1.2 m / min.

[0017] According to the embodiments of the present application, the first cooling water flow is 4000-4200 L / min, and the second cooling water flow is 3400-3600 L / min.

[0018] According to the embodiments of the present application, in the step of locking the cooling water amount of the secondary cooling zone to a constant value, the obtained tail slab shell thickness is 25-30 mm.

[0019] According to the embodiments of the present application, the cooling member is of a rigid structure, and has a welding width smaller than the width of the crystallizer by 18-22 cm, a thickness smaller than the thickness of the crystallizer by 3-7 cm, and an added amount of 1.

[0020] According to the embodiments of the present application, the step of detecting the recess area formed by the slab tail comprises detecting the sealing property of the recess area and the solidification thickness of the shell.

[0021] The solidification thickness of the shell is 25-30 mm.

[0022] The application further provides a high manganese steel prepared by the capping method, and the high manganese steel comprises, in percentage by mass, C 0.9-1.1%, Si 0.4-0.5%, Mn 12-14%, and the balance of Fe and inevitable impurities.

[0023] According to the embodiments of the present 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 the present application, the high manganese steel is processed by 30-50% cold deformation hardening, and the surface hardness is greater than or equal to 500 HBW.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The above-mentioned high manganese steel continuous casting tail blank capping method effectively alleviates the internal stress concentration of the slab caused by sudden change of speed, reduces the crack occurrence rate by reducing the pulling speed in stages and keeping it stable in stages. The slag removal operation is performed in the second pulling speed stable stage to accurately remove the mold liquid surface dross and inclusions and reduce the occurrence of slab surface defects. The light pressing function is cancelled, and the mold wide surface cooling water flow is reduced in stages to avoid excessive cooling of the inner wall of the mold and reduce thermal stress damage. The cooling water quantity of the secondary cooling zone is locked as a constant value to ensure the temperature field uniformity of the slab in the secondary cooling zone, accelerate the solidification of the tail blank, make it quickly form a blank shell with a certain thickness, and avoid the tailing time being too long at low pulling speed, which causes cracks. It can also avoid the tail blank being too hard to damage the fan-shaped section, ensure the tail blank quality, improve the continuous casting process operation rate, and improve the molten steel yield of high manganese steel. The submerged entry nozzle is removed and a cooling element is added in the third pulling speed stage to eliminate the risk of nozzle blockage and accelerate the solidification of the tail part to form a sealed recess area to prevent molten steel leakage. The cooling element can effectively seal and withstand the static pressure of the remaining molten steel, so that the mold liquid surface drops to the target position. The tail blank pulling speed is increased in stages to avoid the tail blank shell bearing shear stress and reduce the occurrence of internal cracks. Through the above-mentioned pulling speed step adjustment, cooling water flow and process step cooperation, the slab defects can be effectively reduced, the quality of the mold and the cast blank can be improved, the cooling effect can be optimized, the tail blank defects can be reduced, and the production efficiency and stability can be improved. The steps of the present application are simple, easy to operate, and low in production cost. The capping operation can be quickly completed when the high manganese steel tail blank is tailed out, and the problem of tail blank bulging is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the drawings shown.

[0028] Figure 1 Figure 1 is a schematic diagram of the relationship between the continuous casting blank pulling speed and the blank pulling time after stopping pouring of "1st flow molten steel";

[0029] Figure 2 Figure 2 is a schematic diagram of the relationship between the continuous casting blank pulling speed and the blank pulling time after stopping pouring of "2nd flow molten steel".

[0030] The objectives, functional features and advantages of the present application will be further illustrated in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort shall fall within the protection scope of the present application.

[0032] In addition, the technical solutions among the various embodiments of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize the combination. When the combination of technical solutions appears to be contradictory or unachievable, it shall be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0033] In the prior art, in the continuous casting pouring production process, there are processes of starting pouring, stabilizing pouring and stopping pouring. For the two non-steady state processes of starting pouring and stopping pouring, production accidents are extremely easy to occur, and at the same time, the risk of uncontrolled slab quality will also be caused. Therefore, more and more researchers shift their research focus to the continuous casting stopping and starting pouring operation, especially the stopping pouring operation. When the tail blank capping is not good and the serious tail molten steel outburst occurs, there will be a risk of welding the fan-shaped section, which affects the yield and increases the production cost. In order to improve the problems existing in the non-steady state process of continuous casting, the present application provides a capping method for high manganese steel continuous casting tail blank, which aims to solve the technical problems of the existing technology that the slab tail appears outburst in the tailing process and increases the production cost.

[0034] To achieve the above-mentioned purpose, the present application provides a capping method for high manganese steel continuous casting tail blank, comprising the following steps:

[0035] Before stopping pouring, the blank pulling speed is reduced from the reference speed to the first speed, and the first speed is kept stable.

[0036] In some embodiments, before stopping pouring, reducing the blank pulling speed from the reference speed to the first speed can reduce the internal defects of the slab caused by too fast speed change. Keeping the stable first speed helps the smooth flow of the molten steel in the crystallizer, reduces the liquid level fluctuation, and improves the crystallization quality. It also helps to reduce the thermal stress and crack risk of the inner wall of the crystallizer, thereby prolonging the service life thereof.

[0037] The first speed is reduced to the second speed, and after the second speed is stably operated, the crystallizer liquid level slagging operation is performed.

[0038] In some embodiments, the first withdrawal speed is reduced to a second withdrawal speed, and after the second withdrawal speed is stabilized, a crystallizer liquid surface slagging operation is performed. After the slagging operation after the second withdrawal speed is stabilized, the stability of the crystallizer liquid surface can be maintained, and the influence of liquid surface fluctuation on the crystallization process is reduced. The slagging operation can effectively remove the scum and inclusions on the liquid surface of the crystallizer, reduce the inclusions into the slab, and significantly improve the surface quality of the slab, and reduce surface defects such as scratches and depressions.

[0039] The light press-down function is cancelled, the crystallizer wide surface cooling water flow rate is reduced from the first cooling water flow rate to the second cooling water flow rate, and the cooling water flow rate of the secondary cooling zone is locked as a constant value.

[0040] In some embodiments, reducing the crystallizer wide surface cooling water flow rate can avoid excessive cooling that causes the inner wall temperature of the crystallizer to be too low, thereby reducing the thermal stress and crack risk of the inner wall of the crystallizer. At the same time, locking the cooling water flow rate of the secondary cooling zone as a constant value can ensure the stability of the cooling process of the slab in the secondary cooling zone, and avoid uneven slab temperature caused by fluctuation of the cooling water flow rate. Through precise control of the cooling process water flow rate, the internal and surface quality of the cast slab can be improved, and defects caused by improper cooling can be reduced.

[0041] In some embodiments, the secondary cooling water flow rate is locked according to the cross section before the end of pouring, the tailing slab is accelerated to solidify, and a slab shell with a certain thickness is quickly formed, while avoiding the tailing out for too long at a low withdrawal speed, which causes cracks. At the same time, by locking the secondary cooling water flow rate of the crystallizer and reducing the cooling of the crystallizer, the tailing slab is prevented from being damaged by the fan-shaped section, the quality of the tailing slab is ensured, the operation rate of the continuous casting process is improved, and the yield of high manganese steel liquid is improved. The problem of mixing pouring of high manganese steel with other steel grades before tailing out in the prior art is solved, the composition of the mixed pouring slab is not controlled, resulting in waste cutting and affecting the yield of the liquid steel.

[0042] After the second withdrawal speed is reduced to a third withdrawal speed, the submerged entry nozzle is removed, and a cooling member is added to the crystallizer.

[0043] In some embodiments, reducing the withdrawal speed to the third withdrawal speed helps to stabilize the solidification of the tailing slab and reduce defects caused by rapid speed changes. Removing the submerged entry nozzle can avoid the problem of poor steel flow caused by nozzle clogging and reduce downtime. Adding a cooling member can further optimize the cooling effect in the crystallizer and ensure the solidification quality of the tail end of the slab.

[0044] In some embodiments, by adding a cooling member during tailing out, the remaining liquid steel can be effectively sealed and withstand the static pressure, so that the liquid surface of the crystallizer drops to a set position.

[0045] In some embodiments, the cooling member is placed in the crystallizer, and the cooling member is timely melted into the center position of the liquid phase of the tail of the cast slab, so as to achieve the purpose of quickly capping the tail of the cast slab.

[0046] When the tail of the slab is moved out of the crystallizer, the recess region formed by the tail of the slab is detected.

[0047] In some embodiments, by detecting the recess region, defects of the tail of the slab can be timely found, and process parameters such as the drawing speed and the cooling water amount can be adjusted according to the detection result, so as to reduce the occurrence of defects of the tail of the slab.

[0048] After the capping of the tail of the slab is completed, the third drawing speed is stepped up to a target drawing speed until the tail of the slab is completely drawn out of the fan-shaped section.

[0049] The target drawing speed is 1.0-1.2 m / min.

[0050] In some embodiments, by stepping up the third drawing speed to the target drawing speed, the internal stress concentration of the slab caused by too fast change of the speed can be avoided, and the generation of defects such as cracks can be reduced. Maintaining the stable target drawing speed during the drawing of the tail of the slab can ensure the quality of the tail of the slab, reduce defects of the tail of the slab caused by the change of the speed, improve the production efficiency, and reduce the downtime.

[0051] In some embodiments, the speed is reduced to 0.6 m / min before the pouring is stopped, the slag is scooped, the liquid slag is scooped clean, the rod is closed, the blind plate is hit, the light pressing down is cancelled, the water flow of the wide surface of the crystallizer is adjusted small, the secondary cooling water is locked, the submerged entry nozzle is taken out, the cooling member is placed, and the stop operation is not allowed during the tailing-out process.

[0052] In some embodiments, by accurately controlling the drawing speed, the cooling water flow, and the addition of the cooling member, the capping method ensures the high-quality solidification of the tail of the slab, reduces defects of the tail of the slab, improves the production efficiency and stability, avoids the occurrence of the rising of the tail of the slab during the tailing-out process, reduces the too long time of the low drawing speed when the tail of the slab is drawn out, avoids the damage of the fan-shaped section caused by the too hard drawing of the tail of the slab, ensures the quality of the tail of the slab, improves the operation rate of the continuous casting process, and improves the yield of the high-manganese steel molten steel.

[0053] The high manganese steel continuous casting tail slab capping method can effectively alleviate the slab internal stress concentration caused by speed mutation, reduce the crack occurrence rate by reducing the pulling speed in stages and keeping it stable in stages. The slag skimming operation is performed in the second pulling speed stable stage to accurately remove the mold liquid surface dross and inclusions and reduce the occurrence of slab surface defects. The light pressing down function is cancelled and the mold wide surface cooling water flow is reduced in stages to avoid excessive cooling of the mold inner wall and reduce the thermal stress damage. The secondary cooling zone cooling water amount is locked as a constant value to ensure the slab temperature field uniformity in the secondary cooling zone, accelerate the tail slab solidification, make the slab shell form quickly with a certain thickness, and avoid the long low pulling speed time at the tail exit to cause cracks. It can also avoid the tail slab over-hard pulling damage to the fan-shaped section, ensure the tail slab quality, improve the continuous casting process operation rate, and improve the high manganese steel molten steel yield. The submerged entry nozzle is removed and the cooling piece is added in the third pulling speed stage to eliminate the nozzle blockage risk and accelerate the tail solidification to form a sealed recess area to prevent molten steel leakage. The cooling piece can effectively seal and withstand the static pressure of the remaining molten steel, so that the mold liquid surface is lowered to the target position. The tail slab pulling speed is increased in stages to avoid the shear stress on the tail slab shell and reduce the internal crack occurrence. Through the above pulling speed stage adjustment, cooling water flow and process step cooperation, the slab defects can be effectively reduced, the mold and cast slab quality can be improved, the cooling effect can be optimized, the tail slab defects can be reduced, and the production efficiency and stability can be improved. The steps of the present application are simple, convenient to operate, and low in production cost. The capping operation can be quickly completed when the high manganese steel tail slab exits, and the tail slab bulging problem is effectively solved.

[0054] In some embodiments, 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.

[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 continuous casting tundish stopper is opened and flows into the mold through the nozzle, the pulling speed is reduced from 0.9 m / min to 0.8 m / min before stopping pouring, the pulling speed is reduced to 0.6 m / min after keeping for 2 min, the slag is removed, the light pressing down is cancelled, the mold wide surface water is reduced, and the secondary cooling water is locked. The pulling speed is reduced to 0.4 m / min, the submerged entry nozzle is removed, the cooling piece is added, the slab tail forms a recess area when the slab tail exits the mold, the tail slab capping is completed, the speed is increased to 0.6 m / min, the speed is increased to 1.0 m / min after keeping for 90 s, and the fan-shaped section is pulled out.

[0057] In some embodiments, the step of increasing the third pulling speed to the target pulling speed in stages comprises:

[0058] The third pulling speed is raised to 0.6-0.7 m / min and maintained for 90-120 s, and then raised to the target pulling speed.

[0059] The target pulling speed is 1.0-1.2 m / min.

[0060] In some embodiments, the target pulling speed is 1.0 m / min. The stepwise raising of the third pulling speed to the target pulling speed can avoid stress concentration in the slab due to too fast speed change, and reduce the generation of cracks and other defects.

[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, the regulation of the cooling water flow rate can avoid excessively low temperature of the inner wall of the crystallizer due to excessive cooling, thereby reducing the thermal stress and crack risk of the inner wall of the crystallizer. By precisely regulating the cooling water flow rate, the internal and surface quality of the cast slab can be improved, and defects caused by improper cooling can be reduced.

[0064] In some embodiments, in the step of locking the cooling water amount of the secondary cooling zone to a constant value, the tail slab shell thickness obtained is 25-30 mm.

[0065] In some embodiments, by optimizing the cooling water amount of the secondary cooling zone, the tail slab shell thickness can be ensured to be between 25-30 mm, which helps to stabilize the solidification of the tail slab and reduce defects of the tail slab.

[0066] In some embodiments, the cooling member is a rigid structure, the welding width of which is 18-22 cm less than the width of the crystallizer, and the thickness of which is 3-7 cm less than the thickness of the crystallizer, and the number of the cooling member added is one.

[0067] In some embodiments, the cooling member is a cooling steel plate, and the rigid structure has a welding width of 20 cm less than the width of the crystallizer and a thickness of 5 cm less than the thickness of the crystallizer, and the number of the cooling member added is one.

[0068] In some embodiments, the cooling member is a rigid structure, which ensures its stability in a high-temperature environment. The welding width and thickness are regulated according to the size of the crystallizer, so that the cooling member can fit the size of the crystallizer, while avoiding unnecessary thermal stress on the crystallizer. The number of the cooling member is regulated to ensure the cooling effect while avoiding excessive cooling, thereby improving the solidification quality of the tail 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 property of the recessed area and the solidification thickness of the shell.

[0070] The solidification thickness of the shell is 25-30 mm.

[0071] In some embodiments, detecting the recessed area formed at the tail of the slab includes: as the shell is shrunk by the crystallizer water cooling, the tail of the cast slab gradually solidifies to form a recess, and the operator needs to check that the recess formed at the tail does not cause the molten steel to flow out and that the recessed part of the tail has a certain solidification thickness.

[0072] The application also provides a high manganese steel prepared by the capping method, and the high manganese steel comprises the following components in percentage by mass: C 0.9-1.1%, Si 0.4-0.5%, Mn 12-14%, and the balance of Fe and inevitable impurities.

[0073] In some embodiments, the composition of the high manganese steel is adjusted to ensure high strength and good toughness, and the processing performance and wear resistance of the steel are improved by optimizing the content of carbon and silicon. Through the synergistic optimization of the composition and the capping method, the high manganese steel has excellent performance and quality, and the controllability and reliability of the overall process are improved.

[0074] In some embodiments, the yield strength of the high manganese steel is 400-700 MPa, the tensile strength is 800-1000 MPa, and the elongation is 20-30%.

[0075] In some embodiments, the yield strength of the high manganese steel enables it to maintain good plastic deformation capacity when subjected to a large stress. The tensile strength ensures the strength and reliability of the high manganese steel in a high stress environment. The high manganese steel has good plastic deformation capacity and can withstand a large deformation without breaking during processing and use.

[0076] In some embodiments, the surface hardness of the high manganese steel is greater than or equal to 500 HBW after 30-50% cold deformation work hardening.

[0077] In some embodiments, the high surface hardness of the high manganese steel improves its wear resistance and service life.

[0078] In order to further understand the application, examples are provided as follows:

[0079] Embodiment 1

[0080] A capping method for a high manganese steel continuous casting tail slab, comprising the following steps:

[0081] When the continuous casting tundish stopper is opened, it flows into the crystallizer through the nozzle. Before stopping casting, the casting speed of the continuous casting machine is reduced from 0.9 m / min to 0.8 m / min, and then kept for 2 min, and then the casting speed is reduced to 0.6 m / min, and after being stable for 1 min, the slag is salvaged, the light pressing down is cancelled, the water flow of the wide surface of the crystallizer is manually changed from 4100 L / min to 3500 L / min, the secondary cooling water is locked, the tail blank solidification is accelerated, and the blank shell strength is ensured. Then the casting speed is reduced to 0.4 m / min, the submerged nozzle is removed, the cooling part is added, when the slab tail leaves the crystallizer, the slab tail forms a concave area, the tail blank is capped, and the casting speed is increased to 0.6 m / min, and then kept for 90 s, and then the casting speed is increased to 1.0 m / min, and then the fan-shaped section is pulled out.

[0082] The modern continuous casting machine is usually designed as a multi-flow continuous casting machine, that is, one crystallizer can cast multiple blanks at the same time. For example, one crystallizer can cast two blanks at the same time, which are called “1-flow molten steel” and “2-flow molten steel”. Among them, Figure 1 The relationship between the continuous casting casting speed and the blank pulling-out time after stopping casting of the “1-flow molten steel” is shown in the schematic diagram. Figure 2 The relationship between the continuous casting casting speed and the blank pulling-out time after stopping casting of the “2-flow molten steel” is shown in the schematic diagram. The compositions of the “1-flow molten steel” and the “2-flow molten steel” are the same as the chemical composition of the high manganese steel of the present application.

[0083] The above high manganese steel continuous casting tail slab capping method effectively alleviates the slab internal stress concentration caused by speed mutation and reduces the crack occurrence rate by reducing the pulling speed in stages and maintaining stage stability. The slag removal operation is performed in the second pulling speed stability stage to accurately remove the mold liquid surface dross and inclusions and reduce the occurrence of slab surface defects. The light pressing down function is cancelled, and the mold wide surface cooling water flow is reduced in stages to avoid excessive cooling of the mold inner wall and reduce thermal stress damage. The locking of the secondary cooling zone cooling water amount is a constant value, which can ensure the uniformity of the slab temperature field in the secondary cooling zone, accelerate the tail slab solidification, make it quickly form a slab shell with a certain thickness, and avoid the long time of low pulling speed when the tail is out, which may cause cracks. It can also avoid the hard pulling of the fan-shaped section of the tail slab, ensure the quality of the tail slab, improve the continuous casting process operation rate, and improve the yield of high manganese steel molten steel. The submerged entry nozzle is removed and a cooling element is added in the third pulling speed stage to eliminate the risk of nozzle blockage, accelerate the tail solidification, form a sealed recess area, and prevent molten steel leakage. The cooling element can effectively seal and withstand the static pressure of the remaining molten steel, so that the mold liquid surface drops to the target position. The tail slab pulling speed is gradually increased to avoid the shear stress on the tail slab shell and reduce the occurrence of internal cracks. Through the above pulling speed step adjustment, cooling water flow and process step cooperation, the slab defects can be effectively reduced, the mold and cast slab quality can be improved, the cooling effect can be optimized, the tail slab defects can be reduced, and the production efficiency and stability can be improved. The steps of the present application are simple, easy to operate, and low in production cost, which can quickly complete the capping operation when the high manganese steel tail slab is out, and effectively solve the problem of tail slab bulging.

[0084] In summary, in the above technical solution of the present application, the above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the contents of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method of capping a high manganese steel continuously cast tail slab, characterized in that, The method comprises the following steps: S1: before stopping casting, the drawing speed is reduced from the reference drawing speed to the first drawing speed, and the first drawing speed is kept stable; S2: the first drawing speed is reduced to the second drawing speed, and after the second drawing speed is kept stable, the crystallizer liquid level is removed and the slag operation is carried out; S3: cancel the light pressing function, reduce the crystallizer wide surface cooling water flow from the first cooling water flow to the second cooling water flow, and lock the cooling water flow of the secondary cooling zone as a constant value; S4: after the second drawing speed is reduced to the third drawing speed, the immersion nozzle is removed, and a cooling piece is added to the crystallizer; S5: when the tail of the slab is removed from the crystallizer, the recess area formed by the tail of the slab is detected; S6: after the tail of the slab is capped, the third drawing speed is stepped up to the target drawing speed until the tail of the slab is completely drawn out of the fan-shaped section; The target drawing speed is 1.0-1.2 m / min.

2. The high manganese steel continuous-casting tail-end slab capping method according to claim 1, characterized by, The first drawing speed is 0.7-0.8 m / min, the second drawing speed is 0.5-0.6 m / min, and the third drawing speed is 0.3-0.4 m / min.

3. The high manganese steel continuous-casting tail-end slab capping method according to claim 1, characterized by, The step of stepping up the third drawing speed to the target drawing speed comprises: The third drawing speed is increased to 0.6-0.7 m / min and kept for 90-120 s, and then increased to the target drawing speed; The target drawing speed is 1.0-1.2 m / min.

4. The capping method of high manganese steel continuous-casting tail slabs according to claim 1, characterized in that, The first cooling water flow is 4000-4200 L / min, and the second cooling water flow is 3400-3600 L / min.

5. The high manganese steel continuous-casting tail-end slab capping method according to claim 1, characterized by In the step of locking the cooling water flow of the secondary cooling zone as a constant value, the tail shell thickness obtained is 25-30 mm.

6. The high manganese steel continuous-casting tail-end slab capping method according to claim 1, characterized by The cooling piece is a rigid structure, the welding width of which is 18-22 cm less than the width of the crystallizer, the thickness of which is 3-7 cm less than the thickness of the crystallizer, and the added amount of the cooling piece is 1.

7. The high manganese steel continuous-casting tail-end slab capping method according to claim 1, characterized by The step of detecting the recess area formed by the tail of the slab comprises detecting the sealing property of the recess area and the solidification thickness of the shell; The solidification thickness of the shell is 25-30 mm.

8. High manganese steel obtainable by the capping process according to any one of claims 1 to 7, characterized in that The components of the high manganese steel, in mass percentage, comprise: C 0.9-1.1%, Si 0.4-0.5%, Mn 12-14%, and the balance is Fe and inevitable impurities.

9. High manganese steel according to claim 8, characterized in that The yield strength of the high manganese steel is 400-700 MPa, the tensile strength is 800-1000 MPa, and the elongation is 20-30%.

10. High manganese steel according to claim 9, characterized in that After 30-50% cold deformation work hardening of the high manganese steel, the surface hardness is ≥500 HBW.

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