High-carbon and high-manganese steel and continuous casting stopping control method thereof

Abstract

The invention provides high-carbon and high-manganese steel and a control method for continuous casting stopping of the high-carbon and high-manganese steel, and the control method comprises the following steps: before stopping the casting, reducing the pulling speed to a first target pulling speed, removing casting powder in a crystallizer after the pulling speed is stabilized, closing a stopper rod, arranging a blind plate, and synchronously reducing the wide-surface cooling water flow of the crystallizer from a first target flow to a second target flow; a secondary cooling water system in front of the straightening section is switched to a semi-automatic flow locking mode, the first target pulling speed is switched to a second target pulling speed, a tail blank mode is started, and the soft reduction function is relieved; after the submersed nozzle is removed, a cooling piece is added into the crystallizer, and the tail blank is continuously pulled out at a third target pulling speed; after the tail blank is completely separated from the crystallizer, running at a fourth target pulling speed for 2-4 minutes; pulling the tail blank out of the fan-shaped section at a fifth target pulling speed; the first target flow rate ranges from 5100 L / min to 6100 L / min; and the second target flow rate is 4000 to 4500 L / min. And the technological process is simple and convenient to operate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel continuous casting, and particularly relates to high-carbon high-manganese steel and a control method for continuous casting stop pouring thereof. BACKGROUND

[0002] High-carbon high-manganese steel is a special high-strength alloy steel, and the carbon content thereof is usually above 1.0% and the manganese content thereof is above 10%. Such a combination of components endows it with excellent wear resistance, so that it can exhibit good wear resistance under high stress and high impact working conditions to meet the design and construction requirements of structural materials in different fields.

[0003] However, the carbon and manganese contents in high-carbon high-manganese steel are very high, which brings many technical difficulties to the production thereof, especially in the whole continuous casting production process. The high-carbon high-manganese steel liquid has poor flowability, which leads to increased difficulty in the pouring and tailing-out stages. The direct tailing-out in the continuous casting stop pouring stage is prone to the occurrence of bulging, and the slab cannot be pulled, which leads to the deviation of the precision of the caster and low production efficiency. At present, some steel plants adopt the ways of mixed pouring tailing-out or tailing-out water punching in the tailing-out stop pouring stage, but the composition of the slab produced by mixed pouring does not meet the composition system of any steel grade, and the mixed pouring slab cannot be used, which causes the waste of production cost. The tailing-out water punching way is complex in operation and unstable in effect. Based on this, the application provides a control method for high-carbon high-manganese steel and continuous casting stop pouring thereof. SUMMARY

[0004] The main purpose of the application is to provide a control method for high-carbon high-manganese steel and continuous casting stop pouring thereof, which aims to solve the technical problems of the direct tailing-out in the continuous casting stop pouring of high-carbon high-manganese steel, which is prone to the occurrence of bulging and low production efficiency in the prior art.

[0005] To achieve the above-mentioned purpose, the application provides a control method for high-carbon high-manganese steel continuous casting stop pouring, and the steps include:

[0006] Before stop pouring, the pulling speed is reduced to a first target pulling speed, and after stabilization, the mold protection slag is removed, the stopper is closed and the blind plate is set, and the mold wide surface cooling water flow is simultaneously reduced from a first target flow to a second target flow.

[0007] The two-cooling water system before the straightening section is switched to a semi-automatic locking flow mode to maintain the second target flow of the cooling water, the first target pulling speed is switched to a second target pulling speed, the tailing-out mode is enabled and the light press-down function is released.

[0008] After the submerged entry nozzle is removed, a cooling piece is added to the mold, and the tailing-out slab is continuously pulled out at a third target pulling speed.

[0009] After the tailing-out slab completely separates from the mold, the operation is carried out at a fourth target pulling speed for 2-4 minutes; and then the tailing-out slab is pulled out of the fan-shaped section at a fifth target pulling speed.

[0010] The first target flow rate is 5100-6100 L / min, and the second target flow rate is 4000-4500 L / min.

[0011] The fifth target pulling speed > the fourth target pulling speed > the first target pulling speed >= the second target pulling speed >= the third target pulling speed.

[0012] According to the embodiments of the present application, the first target pulling speed is 0.6-0.9 m / min, the second target pulling speed is 0.4-0.6 m / min, the third target pulling speed is 0.2-0.4 m / min, the fourth target pulling speed is 0.9-1.1 m / min, and the fifth target pulling speed is 1.2-2.0 m / min.

[0013] According to the embodiments of the present application, if the molten steel overflows after the tail strand completely separates from the crystallizer, the tail strand is directly pulled out of the fan-shaped section at the fifth target pulling speed, and no stop operation is performed.

[0014] According to the embodiments of the present application, the cooling member is a rigid structure formed by welding a cooling steel plate or a flat steel.

[0015] According to the embodiments of the present application, after the submerged entry nozzle is removed, in the step of adding the cooling member into the crystallizer, the cooling spring and / or the iron filings are selectively added according to the solidification state of the tail strand.

[0016] According to the embodiments of the present application, the control method for high-carbon high-manganese steel continuous casting stop pouring further comprises: after the tail strand is pulled out of the fan-shaped section, the continuous casting machine after stop pouring is checked to ensure that the precision of the continuous casting machine meets the standard.

[0017] According to the embodiments of the present application, the first target flow rate decreases to the second target flow rate at a rate of 50-100 L / min·s.

[0018] The present application also provides a high-carbon high-manganese steel prepared by the above control method, and the components of the high-carbon high-manganese steel, in terms of mass percentage, include: C 0.90-1.40%, Mn 11.0-14.0%, Si 0.30-0.70%, P <=0.035%, S <=0.020%, Al 0.015-0.10%, and the balance is Fe and inevitable impurities.

[0019] According to the embodiments of the present application, the yield strength of the high-carbon high-manganese steel is 400-500 MPa, the tensile strength is 900-1000 MPa, and the elongation is >=15%.

[0020] According to the embodiments of the present application, the linear expansion coefficient of the high-carbon high-manganese steel at high temperature is 1.5-2.0 times that of ordinary steel.

[0021] The surface hardness after work hardening is HB550 or above.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] The application provides a high-carbon high-manganese steel and a control method for continuous casting stop pouring of the high-carbon high-manganese steel. The control method comprises the following steps: before stop pouring, the pulling speed is reduced to a first target pulling speed, and after stabilization, the protective slag in the crystallizer is removed, so that the lubrication between the inner wall of the crystallizer and the casting blank is ensured, and the crystallizer sticking and the surface defects of the casting blank caused by the residual protective slag are avoided, thereby improving the service life of the crystallizer and the surface quality of the casting blank. By adjusting the pulling speed and the cooling water flow in stages, the continuous casting process is more smoothly transitioned, the fluctuations in the continuous casting process caused by parameter mutation are reduced, the stability of the continuous casting is improved, the surface cracks and internal defects of the casting blank caused by the fluctuations in the cooling water flow are reduced, and the quality of the casting blank is ensured. By enabling the tail blank mode and removing the light press-down function, and by adding a cooling piece after removing the submerged nozzle, the tail blank can quickly separate from the segment at a suitable pulling speed and cooling condition, the efficiency of the tail blank treatment is improved, the residence time of the tail blank in the segment is reduced, and the risk in the tail blank treatment process is reduced. The present application realizes the direct tailing-out of the high-carbon high-manganese steel by the cooperation of parameters and process modes, which does not damage the caster, does not affect the precision of the caster, avoids the generation of waste slabs caused by mixed pouring tailing-out, takes into account the advantages of the above-mentioned direct tailing-out and mixed pouring tailing-out, avoids the respective risks, and can produce good economic benefits. Moreover, the control method is convenient to operate, reduces the production cost, and is suitable for industrial continuous production. BRIEF DESCRIPTION OF DRAWINGS

[0024] 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 the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0025] Figure 1 The process flow chart of the control method for continuous casting stop pouring of the high-carbon high-manganese steel of the present application;

[0026] Figure 2 The microscope graph of the high-carbon high-manganese steel of an embodiment of the present application; wherein (a) is magnified 200 times, and (b) is magnified 50 times;

[0027] Figure 3 The internal organization graphs corresponding to different length regions of the high-carbon high-manganese steel slab prepared by the control method for continuous casting stop pouring of the high-carbon high-manganese steel of the present application.

[0028] The objectives, functional characteristics and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be apparently 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 work are within the protection scope of the present application.

[0030] Moreover, 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 the technical solutions appears to be contradictory or unachievable, it should be considered that the combination of the technical solutions does not exist and is not within the protection scope required by the present application.

[0031] High manganese steel refers to high-strength alloy steel with manganese content of more than 10%. Due to the different manganese content, it has different material characteristics from traditional low-carbon steel, such as work hardening, wear resistance, high toughness, low temperature resistance, etc., which can meet the design and construction requirements of structural materials in different fields. However, high manganese steel has very prominent technical difficulties. First, with the increase of manganese content, the molten steel has poor flowability, low thermal conductivity, large linear shrinkage, small solidus and liquidus temperature difference, etc., which increases the difficulty of pouring and tailing out of high manganese steel casting blank, and easily causes internal and external defects such as segregation and cracks. High-carbon high-manganese steel combines the characteristics of high-carbon steel and high-manganese steel, with high strength and large hardness. Its mechanical strength under high temperature is 2-3 times that of low-alloy steel or plain carbon steel, and it is prone to surface transverse crack defects after straightening of the slab. The molten steel does not change phase during solidification, the grains merge and grow, and it belongs to intrinsic coarse-grained steel. Moreover, the heat transfer coefficient is low, and the grain boundary is prone to cracking and developing into serious internal cracks when produced in the mode of continuous casting with fast cooling speed. The volume shrinkage coefficient is large, and it is easy to form a large air gap in the mold, thereby causing a leakage accident.

[0032] Due to the high carbon content in high-carbon high-manganese steel, a large amount of carbides are precipitated during solidification, and large section continuous casting is prone to defects such as center segregation, center porosity and center shrinkage. Due to these characteristics of high-carbon high-manganese steel during solidification, it brings great difficulty to continuous casting production, especially in the tailing out and stopping pouring stage. Some steel plants use mixed pouring tailing out, and some steel plants use tailing out and water punching.

[0033] Due to the above characteristics of high-carbon high-manganese steel, the castability is poor in the continuous casting production process, the linear shrinkage is small when the tailing out, and it is often difficult to do well in the tailing out capping, and the direct tailing out method is prone to the situation of rising; in addition, due to the long time of low pulling speed, the corresponding slab stays in the fan-shaped section for a long time, the slab cools faster, the surface temperature decreases rapidly (the tail part has a lower temperature due to the characteristics), the slab strength increases, the fan-shaped section needs to bear a larger force to resist the deformation of the slab, resulting in a sharp increase in the driving roller torque of the fan-shaped section in the tailing out stage, the slab cannot be pulled, the slab slips, and in severe cases, the fan-shaped section breaks and leaks, the opening degree of the fan-shaped section increases, the precision of the caster deviates, the maintenance time of the caster increases, and the production efficiency is affected.

[0034] And the mixed pouring tailing out method (in the last furnace of the high-manganese steel pouring, other steel is appropriately arranged to the pouring, when the high-manganese steel pouring is finished, the ladle tonnage reaches a lower tonnage, the steel pouring is opened in the ladle, and then the pouring is finished until the tailing out) avoids the damage of the direct tailing out of the high-carbon high-manganese steel to the caster, but the composition of the slab produced by the mixed pouring of the two steel grades does not meet the composition system of any one steel grade, the mixed pouring slab cannot be used and can only be cut and wasted, resulting in waste of production cost, and the temperature in the mold changes sharply during the mixed pouring stage, the sticking alarm occurs frequently, and the leakage accident is prone to occur. Therefore, the present application provides a control method for high-carbon high-manganese steel continuous casting stop pouring, which aims to solve the technical problems of the prior art that the high-carbon high-manganese steel continuous casting stop pouring directly tailing out is prone to rising and low production efficiency.

[0035] To achieve the above purpose, the present application provides a control method for high-carbon high-manganese steel continuous casting stop pouring, comprising the following steps:

[0036] S1: before stop pouring, the pulling speed is reduced to a first target pulling speed, after stabilization, the mold powder in the mold is removed, the stopper is closed and the blind plate is set, and the mold wide surface cooling water flow is simultaneously reduced from a first target flow to a second target flow; wherein the first target flow is 5100-6100 L / min; the second target flow is 4000-4500 L / min.

[0037] In some embodiments, reducing the casting speed to the first target casting speed before stopping casting can make the stress in the casting blank more uniform during solidification. The composition characteristics of high-carbon high-manganese steel make it prone to stress concentration during solidification, and reducing the casting speed can help to slow down the accumulation of stress in the casting blank, thereby reducing the probability of internal crack generation. After the first target casting speed is stable, the flow state of the molten steel in the mold will be more stable, which can avoid the protective slag being rolled into the surface of the casting blank in the mold when the protective slag is removed. Removing the protective slag can ensure the cleanliness and smoothness of the surface of the casting blank. Closing the stopper and setting the blind plate during stopping casting can prevent unnecessary turbulent flow of the molten steel in the mold, effectively control the flow state of the molten steel in the mold, and reduce the generation of surface roll slag and other defects. Synchronously adjusting the cooling water flow rate of the wide face of the mold from the first target flow rate to the second target flow rate can better control the solidification process of the casting blank. The thermal conductivity of high-carbon high-manganese steel is relatively poor, and by precisely controlling the cooling water flow rate, the solidification speed of the casting blank during the stopping casting stage is adjusted and controlled, which can avoid surface crack defects caused by excessive or insufficient cooling.

[0038] In some embodiments, before stopping casting, the casting speed is reduced and kept stable, so that the subsequent operations can be carried out under relatively stable conditions, avoiding the confusion caused by unstable casting speed, thereby shortening the stopping casting process time.

[0039] In some embodiments, the protective slag in the mold is removed before the stopper is closed, which can avoid safety accidents such as molten steel leakage caused by improper operation sequence. At the same time, the setting of the blind plate and other measures also increase the safety of the operation and reduce the risk of molten steel splashing and high-temperature scalding.

[0040] S2: Switching the secondary cooling water system before the straightening section to a semi-automatic locking flow mode to maintain the second target flow rate of the cooling water, switching the first target casting speed to the second target casting speed, enabling the tail blank mode and disabling the soft reduction function.

[0041] In some embodiments, after switching to the semi-automatic locking flow mode, the secondary cooling water system can cool the casting blank at a stable flow rate. This can avoid uneven surface temperature of the casting blank caused by fluctuation of the cooling water flow rate, thereby reducing surface crack defects. Frequent intervention of the operator on the cooling system is reduced, improving the stability and reliability of the operation. At the same time, the temperature of the surface of the casting blank can also be controlled, reducing surface oxidation caused by local overheating or insufficient cooling, which helps to maintain the cleanliness and smoothness of the surface of the casting blank. By switching the casting speed to the second target casting speed, the uniform solidification speed of the casting blank is improved. Stable casting speed helps to reduce the accumulation of internal stress, thereby reducing the risk of internal cracks.

[0042] In some embodiments, the tail-out stage is due to the lack of molten steel to supplement the solidification shrinkage of the liquid hole, if the light pressure is put into the mushy zone at the end of solidification, the reverse flow of the molten steel at the end of solidification is generated under the extrusion of the fan-shaped segment, which causes the damage of the already capped shell, the outflow of the molten steel, the adhesion of the fan-shaped segment roller, and the damage of the caster equipment under the action of the straightening machine. Therefore, the tail blank mode is started and the light pressure function is released in the tail-out stage, which can improve the quality of the casting blank, reduce the surface and internal defects, reduce the equipment wear and failure, thereby reducing the scrap rate and equipment maintenance cost.

[0043] In some embodiments, the casting speed is reduced to 0.8 m / min before stopping pouring, the slag is scooped out after stabilizing for 1 min, the liquid slag is scooped out cleanly, the rod is closed and the blind plate is hit, the water on the wide surface of the crystallizer is manually changed from 5100 L / min to 4500 L / min, the semi-automatic water locking is performed on the two cooling water before the straightening segment, the casting speed is pulled to 0.6 m / min to switch to the tail-out mode, and the light pressure is cancelled.

[0044] S3: After removing the submerged nozzle, a cooling element is added to the crystallizer, and the tail blank is continuously pulled out at a third target casting speed.

[0045] In some embodiments, after removing the submerged nozzle, the molten steel in the crystallizer flows smoothly. The addition of the cooling element can effectively reduce the temperature in the crystallizer, reduce the risk of adhesion between the molten steel and the inner wall of the crystallizer, and effectively prevent the occurrence of the leakage phenomenon. The addition of the cooling element can also quickly reduce the temperature in the crystallizer, rapidly solidify the surface of the casting blank, and reduce the surface cracks caused by high temperature.

[0046] In some embodiments, the addition of the cooling element to the crystallizer can quickly cool and solidify the surface of the casting blank, reduce the size fluctuation caused by temperature change, ensure the size and shape of the tail blank, and improve the quality of the tail blank. Continuously pulling out the tail blank at a third target casting speed can reduce the residence time of the tail blank in the fan-shaped segment, shorten the processing time of the tail blank, reduce the downtime caused by improper processing of the tail blank, and improve the operation efficiency of the continuous casting machine.

[0047] In some embodiments, after removing the lower nozzle, a cooling element (such as a cooling element or a cooling steel plate) is added, the crystallizer is pulled out at a speed of 0.4 m / min, the cooling spring and iron filings are prepared during this process, and the addition is selected according to the solidification condition of the tail blank. The tail-out process is not allowed to be stopped.

[0048] S4: After the tail blank completely separates from the crystallizer, run at a fourth target casting speed for 2-4 minutes; then pull out the tail blank from the fan-shaped segment at a fifth target casting speed. The fifth target casting speed > the fourth target casting speed > the first target casting speed ≥ the second target casting speed ≥ the third target casting speed.

[0049] In some embodiments, after the tail blank completely separates in the crystallizer, the fourth target pulling speed is used for 2-4 minutes, which is beneficial to reduce the crack leakage phenomenon of the tail blank in the fan-shaped section due to excessive temperature or insufficient cooling, and makes the cooling and solidification process of the tail blank in the fan-shaped section more stable. The fifth target pulling speed is used to pull the tail blank out of the fan-shaped section, which reduces the residence time of the tail blank in the fan-shaped section, thereby reducing the downtime caused by improper handling of the tail blank, and improving the operation efficiency of the continuous casting machine.

[0050] In some embodiments, after the tail blank exits the crystallizer, the pulling speed is increased to 0.9 m / min and maintained for 3 min, and then increased to 1.5 m / min to pull out of the fan-shaped section. If it is found that the tail blank is rising, it is directly pulled out of the continuous casting machine at a pulling speed of 1.5 m / min, and stopping is strictly prohibited. After stopping pouring, the status of the casting machine is checked to ensure the accuracy of the casting machine.

[0051] In some embodiments, the control method of the present application is suitable for the tail-out and stop-pouring field of high-carbon high-manganese steel.

[0052] The above-mentioned control method for continuous casting and stopping pouring of high-carbon high-manganese steel reduces the pulling speed to the first target pulling speed before stopping pouring, removes the protective slag in the crystallizer after stabilization, ensures good lubrication between the inner wall of the crystallizer and the cast blank, avoids the sticking of the crystallizer and the surface defects of the cast blank caused by residual protective slag, and improves the service life of the crystallizer and the surface quality of the cast blank. By adjusting the pulling speed and the cooling water flow in stages, the continuous casting process is more smoothly transitioned, the fluctuations in the continuous casting process caused by parameter mutations are reduced, the stability of the continuous casting is improved, the surface cracks and internal defects of the cast blank caused by fluctuations in the cooling water flow are reduced, and the quality of the cast blank is ensured. Enabling the tail blank mode and disabling the soft reduction function, and adding a cooling element after removing the submerged nozzle, enable the tail blank to quickly separate from the crystallizer at a suitable pulling speed and cooling condition, improve the efficiency of the tail blank handling, reduce the residence time of the tail blank in the fan-shaped section, and reduce the risk in the tail blank handling process. The present application realizes the direct tail-out of high-carbon high-manganese steel through the cooperation of parameters and process modes, which does not damage the casting machine, does not affect the accuracy of the casting machine, avoids the production of waste slabs caused by mixed pouring tail-out, takes into account the advantages of the above-mentioned direct tail-out and mixed pouring tail-out, and avoids the respective risks, thereby achieving good economic benefits. Moreover, the control method for continuous casting and stopping pouring of the present application can realize the direct tail-out of high-carbon high-manganese steel, which does not affect the state of the casting machine, avoids the production of waste slabs caused by mixed pouring tail-out, takes into account the advantages of the above-mentioned two tail-outs, avoids the respective risks, and achieves good economic benefits. The control method of the present application is convenient to operate, reduces production costs, and is suitable for industrial continuous production.

[0053] In some embodiments, the first target pulling speed is 0.6-0.9 m / min; the second target pulling speed is 0.4-0.6; the third target pulling speed is 0.2-0.4 m / min; the fourth target pulling speed is 0.9-1.1 m / min; and the fifth target pulling speed is 1.2-2.0 m / min.

[0054] In some embodiments, the first target pulling speed is 0.8 m / min; the second target pulling speed is 0.6; the third target pulling speed is 0.4 m / min; the fourth target pulling speed is 0.9 m / min; and the fifth target pulling speed is 1.5 m / min.

[0055] In some embodiments, before the continuous casting is stopped, the first target pulling speed is adjusted to stabilize the formation of the casting blank and the flow of the molten steel in the mold, and to reduce the friction between the casting blank and the inner wall of the mold, thereby prolonging the service life of the mold. The second target pulling speed is switched to shorten the solidification time of the casting blank and improve the production efficiency of the continuous casting machine. In the tail blank processing stage, the third target pulling speed is reduced to achieve stable cooling and solidification of the tail blank and reduce defects of the tail blank. After the tail blank completely separates from the mold, the fourth target pulling speed of 0.9 m / min is used for 2-4 minutes to quickly pull the tail blank out of the mold, reduce the residence time of the tail blank in the fan-shaped section, and improve the cooling efficiency. It also helps to reduce surface cracks of the tail blank caused by rapid temperature change in the fan-shaped section. The fifth target pulling speed is adjusted to pull the tail blank out of the fan-shaped section to quickly complete the processing of the tail blank, reduce the friction of the tail blank in the fan-shaped section, and prolong the service life of the fan-shaped section. By reasonably setting the pulling speed at different stages, the continuous casting process can be significantly optimized, the quality and production efficiency of the casting blank can be improved, and the equipment wear and failure risk can be reduced.

[0056] In some embodiments, in the S4 step, if the molten steel overflows after the tail blank completely separates from the mold, the fifth target pulling speed is directly used to pull the tail blank out of the fan-shaped section without performing a shutdown operation.

[0057] In some embodiments, when the molten steel overflows in the fan-shaped section, the molten steel solidification will adhere to the rollers. The fifth target pulling speed is directly used to pull the tail blank out of the fan-shaped section, which can quickly reduce the contact time between the molten steel and the rollers of the fan-shaped section, avoid overflow or other equipment failures caused by molten steel overflow, protect the safe operation of the continuous casting equipment, and reduce the downtime.

[0058] In some embodiments, the cooling member is a rigid structure formed by welding a cooling steel plate or a flat steel.

[0059] In some embodiments, the shape and size of the cooling member are adapted to the crystallizer and the cast slab to achieve the rapid cooling effect of the cooling member. The cooling steel plate or flat steel has good thermal conductivity and mechanical strength, can quickly conduct heat from the surface of the cast slab to the cooling medium, reduce the residence time of the tail in the fan-shaped section, and achieve rapid cooling. The uniform cooling process helps to reduce stress concentration in the tail and reduce the risk of internal cracks, improving the internal quality of the tail.

[0060] In some embodiments, in the S3 step, cooling springs and / or iron filings are selectively added according to the solidification state of the tail.

[0061] In some embodiments, cooling springs and / or iron filings are selectively added according to the solidification state of the tail, and the tail-out process does not allow for stoppage. The cooling spring is made of a high-thermal-conductivity metal material, such as copper alloy or aluminum alloy. The cooling spring has good thermal conductivity and can quickly conduct heat from the surface of the cast slab to the cooling medium.

[0062] In some embodiments, to improve cooling efficiency, the cooling spring is adjusted to a spiral shape to increase the contact area with the surface of the cast slab. By closely contacting the surface of the cast slab, the cooling spring quickly conducts heat and accelerates the cooling process of the cast slab.

[0063] In some embodiments, iron filings have high specific heat capacity and thermal conductivity, and can absorb and conduct heat. By contacting the surface of the cast slab, the iron filings absorb heat and conduct it to the cooling medium, thereby accelerating the cooling of the cast slab. At the same time, the iron filings can fill the small gaps on the surface of the cast slab, reducing heat loss. This achieves a more uniform cooling effect and reduces surface cracking caused by uneven cooling.

[0064] In some embodiments, the method for controlling the continuous casting of high-carbon high-manganese steel also includes, after the tail is pulled out of the fan-shaped section, inspecting the continuous casting machine after stopping to ensure that the precision of the continuous casting machine meets the standards.

[0065] In some embodiments, after the continuous casting of high-carbon high-manganese steel is stopped, the continuous casting machine is inspected to ensure that its precision meets the standards. This inspection ensures the precision of the mechanical, electrical and hydraulic systems of the equipment, prevents equipment failure, improves the quality of the cast slab, reduces downtime, improves production efficiency, and optimizes the maintenance and operation efficiency of the continuous casting machine.

[0066] In some embodiments, in the S1 step, the first target flow rate is reduced to the second target flow rate at a rate of 50-100 L / min·s.

[0067] In some embodiments, the flow rate is adjusted by a specific rate so that the flow rate changes smoothly, which can ensure the uniformity of the cooling process of the casting blank at the time of stopping casting, reduce the accumulation of thermal stress, and avoid the generation of internal cracks and surface defects.

[0068] The application further provides a high-carbon high-manganese steel prepared by the control method for continuous casting stopping, and the high-carbon high-manganese steel comprises the following components in percentage by mass: C 0.90-1.40%, Mn

[0069] 11.0-14.0%, Si 0.30-0.70%, P≤0.035%, S≤0.020%, Al 0.015-0.10%, and the balance of Fe and inevitable impurities.

[0070] In some embodiments, the carbon element can improve the strength and hardness of the steel. The carbon content of 0.90-1.40% makes the steel have high hardness and wear resistance. The manganese element can improve the strength and toughness of the steel, and improve the hardenability of the steel. The high manganese content significantly improves the strength and toughness of the steel. The silicon element and the aluminum element can remove oxygen in the steel and improve the purity of the steel. Controlling the content of silicon and aluminum elements helps to improve the oxidation resistance of the steel.

[0071] The high-carbon high-manganese steel provided by the application has high strength, high toughness and good wear resistance by reasonably controlling the content of each component and accurately controlling the process parameters in the continuous casting stopping process, and has a wide application prospect.

[0072] In some embodiments, the yield strength of the high-carbon high-manganese steel is 400-500 MPa, the tensile strength is 900-1000 MPa, and the elongation is ≥15%.

[0073] In some embodiments, the linear expansion coefficient of the high-carbon high-manganese steel at high temperature is 1.5-2.0 times that of ordinary steel;

[0074] After work hardening, the surface hardness of the high-carbon high-manganese steel is HB550 or above.

[0075] In some embodiments, after work hardening, the surface hardness of the high-carbon high-manganese steel is HB550 or above, the surface has high wear resistance and scratch resistance, and the service life of the part can be prolonged. It is suitable for mining machinery, engineering machinery parts and other applications in high wear environment.

[0076] In order to further understand the application, examples are given as follows:

[0077] Example 1

[0078] The production of high-carbon high-manganese steel MN13 in February 2025, the tail out of the pouring operation is carried out according to the above steps, and the cooling piece is added when the tail is out, the crystallizer wide surface water is changed, the light pressing down is cancelled, the secondary cooling water is locked, and the specified drawing speed is drawn out of the crystallizer. Among them, the drawing speed is reduced to 0.8 m / min before stopping pouring, and after stabilizing for 1 min, the slag is scooped, the liquid slag is scooped clean, the rod is closed and the blind plate is hit, at the same time, the crystallizer wide surface water is manually changed from 5100 L / min to 4500 L / min, the secondary cooling water before the straightening section is automatically locked, the drawing speed is pulled to 0.6 m / min to turn the tail out mode, and the light pressing down is cancelled. After removing the submerged water nozzle, the cooling piece is added, and the crystallizer is drawn out at a speed of 0.4 m / min. In this process, the cooling spring and iron filings are prepared, and are selectively added according to the solidification condition of the tail blank. The tailing process is not allowed to have a stop operation. After the tail blank is drawn out of the crystallizer, the drawing speed is increased to 0.9 m / min, and then kept for 3 min, and then increased to 1.5 m / min to draw out the fan-shaped section. From the solidification shrinkage of the tail blank inside the crystallizer, no abnormality is found, and the tail blank can be completely solidified before being drawn out of the crystallizer, and the tailing process is controlled.

[0079] wherein, Figure 1 is the process flow chart of the high-carbon high-manganese steel continuous casting stop pouring control method of the application; Figure 2 is a microscope graph of high-carbon high-manganese steel according to an embodiment of the application, wherein, Figure 2 (a) magnification 200 times, Figure 2 (b) magnification 50 times; Figure 3 is the internal organization graph corresponding to different length regions of the high-carbon high-manganese steel slab prepared by the high-carbon high-manganese steel continuous casting stop pouring control method of the application.

[0080] In combination with Figure 2 It can be seen that the internal organization of high-carbon high-manganese steel is uniform, and no cracks are generated. From Figure 3It can be seen that in the continuous casting process, the solidification structure of the casting blank is usually divided into equiaxed crystal zone, mixed crystal zone, columnar crystal zone and surface fine crystal zone. Among them, the equiaxed crystal zone is located at the center of the casting blank, and the grains in the equiaxed crystal zone are equiaxed. In the equiaxed crystal zone, the cooling speed of the molten steel is slow, and the grains have enough time to grow freely, so the grains are relatively coarse. The mixed crystal zone is located between the equiaxed crystal zone and the columnar crystal zone. The mixed crystal zone contains mixed structure of equiaxed crystals and columnar crystals. The formation of the mixed crystal zone is due to the moderate cooling speed in the region, which can promote the formation of equiaxed crystals and the growth of columnar crystals. It has certain strength, plasticity and toughness. The columnar crystal zone is located in the middle of the casting blank, close to the surface but not including the surface fine crystal zone. The grains in the columnar crystal zone are columnar, and the grains grow along the heat flow direction, usually perpendicular to the surface of the casting blank. In the columnar crystal zone, the cooling speed of the molten steel is fast. The surface fine crystal zone is located at the outermost layer of the casting blank, close to the mold wall. Because the cooling speed of the surface fine crystal zone is extremely fast, the molten steel solidifies rapidly, therefore, the grain size of the surface fine crystal zone is small. The grain size of the surface fine crystal zone is small, has high strength and hardness, and also has good plasticity and toughness, which can effectively reduce the formation of cracks and improve the surface quality of the casting blank. In the continuous casting process, by optimizing the cooling conditions (such as mold cooling water flow, secondary cooling zone cooling water distribution, etc.) and controlling the casting speed, the solidification of each region can be adjusted, so as to improve the overall quality and performance of the casting blank.

[0081] The above-mentioned control method of high-carbon high-manganese steel continuous casting stop pouring, by reducing the casting speed to the first target casting speed before stop pouring, and removing the mold powder after stabilizing, ensures good lubrication between the inner wall of the mold and the casting blank, avoids the sticking of the mold and the surface defects of the casting blank caused by the residual mold powder, and improves the service life of the mold and the surface quality of the casting blank. By adjusting the casting speed and cooling water flow in stages, the continuous casting process is more smoothly transitioned, the fluctuations in the continuous casting process caused by parameter mutations are reduced, the stability of the continuous casting is improved, the surface cracks and internal defects of the casting blank caused by the fluctuations in the cooling water flow are reduced, which helps to ensure the quality of the casting blank. Enabling the tail blank mode and removing the light press-down function, and adding a cooling piece after removing the submerged nozzle, enable the tail blank to quickly separate from the mold under appropriate casting speed and cooling conditions, improve the efficiency of tail blank treatment, reduce the residence time of the tail blank in the fan-shaped section, and reduce the risk in the tail blank treatment process. The present application realizes the direct tailing out of high-carbon high-manganese steel through the cooperation of parameters and process modes, which does not damage the caster and does not affect the precision of the caster, avoids the production of waste slabs caused by mixed pouring tailing out, and can produce good economic benefits.

[0082] The application further provides a high-carbon high-manganese steel, by reasonably controlling the content of each component and precisely regulating the process parameters in the continuous casting stopping process, the obtained high-carbon high-manganese steel has high strength, high toughness and good wear resistance, and has a wide application prospect. After work hardening, the surface hardness of the high-carbon high-manganese steel is above HB550 level, the surface has high wear resistance and scratch resistance, and the service life of the part can be prolonged. It is suitable for mining machinery, engineering machinery parts and other applications under high wear environment. Moreover, the control method of the application is convenient to operate, reduces the production cost, and is suitable for industrial continuous production.

[0083] To sum up, in the above technical scheme of the application, the above is only the preferred embodiment of the application, and does not limit the patent scope of the application, and any equivalent structural transformation made under the technical concept of the application, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel, characterized in that the steps are as follows: include: S1: Before stopping casting, reduce the casting speed to the first target casting speed. After stabilizing, remove the protective slag in the crystallizer, close the stopper rod and set the blind plate. Simultaneously reduce the cooling water flow rate of the wide face of the crystallizer from the first target flow rate to the second target flow rate. S2: Switch the secondary cooling water system before the straightening section to semi-automatic locked flow mode to maintain the second target flow of cooling water, switch the first target pulling speed to the second target pulling speed, enable the tail billet mode and deactivate the light pressing function. S3: After removing the immersion nozzle, add a cooling component into the crystallizer and continuously pull out the tail billet at the third target pulling speed; S4: After the tail billet has completely left the crystallizer, run at the fourth target pulling speed for 2 to 4 minutes; then pull the tail billet out of the fan-shaped section at the fifth target pulling speed; The first target flow rate is 5100–6100 L / min; the second target flow rate is 4000–4500 L / min. The fifth target pulling speed > the fourth target pulling speed > the first target pulling speed ≥ the second target pulling speed ≥ the third target pulling speed.

2. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, The first target pulling speed is 0.6–0.9 m / min; the second target pulling speed is 0.4–0.6 m / min; the third target pulling speed is 0.2–0.4 m / min; the fourth target pulling speed is 0.9–1.1 m / min; and the fifth target pulling speed is 1.2–2.0 m / min.

3. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, In step S4, if molten steel surges after the tail billet completely leaves the crystallizer, the tail billet is pulled out of the fan-shaped section directly at the fifth target pulling speed, and no shutdown operation is performed.

4. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, The cooling component is a rigid structure welded from cooling steel plates or flat steel.

5. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, In step S3, cooling springs and / or iron filings are selectively added depending on the solidification state of the tail billet.

6. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, It also includes inspecting the continuous casting machine after the tail billet is pulled out of the fan-shaped section to ensure that the accuracy of the continuous casting machine meets the standards.

7. The method for controlling the shutdown of continuous casting of high-carbon, high-manganese steel according to claim 1, characterized in that, In step S1, the first target flow rate is reduced to the second target flow rate at a rate of 50-100 L / min·s.

8. A high-carbon, high-manganese steel produced by the control method according to any one of claims 1 to 7, characterized in that, The composition of the high-carbon high-manganese steel, by mass percentage, includes: C 0.90-1.40%, Mn 11.0-14.0%, Si 0.30-0.70%, P≤0.035%, S≤0.020%, Al 0.015-0.10%, with the balance being Fe and unavoidable impurities.

9. The high-carbon, high-manganese steel according to claim 8, characterized in that, The high-carbon, high-manganese steel has a yield strength of 400–500 MPa, a tensile strength of 900–1000 MPa, and an elongation of ≥15%.

10. The high-carbon, high-manganese steel according to claim 8, characterized in that, The coefficient of linear expansion of the high-carbon, high-manganese steel at high temperatures is 1.5 to 2.0 times that of ordinary steel. The surface hardness after work hardening is HB550 or higher.

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