Method for stably controlling surface quality of high-carbon steel continuous casting billet

Abstract

The invention provides a method for stably controlling the surface quality of a high-carbon steel continuous casting billet, which comprises the following steps: high-carbon steel refined molten steel is poured, and the superheat degree of a tundish of the high-carbon steel refined molten steel is 10-25 DEG C; casting powder is added after steel drawing; the pulling speed of the casting is 0.85 to 1.30 m / min; and the high-carbon steel continuous casting billet obtained through pouring is cooled. According to the method for stabilizing the surface quality of the high-carbon steel continuous casting billet, through optimization and adjustment of a production process and cooperation with special casting powder, process parameters such as the pulling speed, the superheat degree and the one-cooling-water slow cooling mode special for the high-carbon steel are formulated, the quality stability of the high-carbon steel is effectively improved, and the percent of pass of the casting billet is increased.

Description

Technical Field

[0001] The invention relates to the technical field of high carbon steel preparation, and in particular to a method for stabilizing the surface quality of a high carbon steel continuous casting billet. Background Art

[0002] In the slab continuous casting process, molten steel with a certain degree of superheat flows out from the submerged nozzle and gradually solidifies into a billet near the wall of the crystallizer. In this process, the molten steel circulating on the crystallizer is first cooled to the solidification temperature of the steel by the strong cooling effect of the crystallizer at the convex part of the meniscus, forming a weak primary billet shell.

[0003] Due to the vibration of the crystallizer, the molten protective slag near the meniscus slowly flows into the slag channel between the copper plate and the billet shell. Under the action of the periodically changing slag channel pressure of the protective slag channel and the static pressure of the molten steel, the primary billet shell begins to deform, and then forms the billet vibration mark. Sulfur and phosphorus elements will be segregated at the grain boundary of the billet at the bottom of the deep vibration mark. Due to the influence of element enrichment, a low-melting-point liquid phase film is formed at the grain boundary, resulting in a significant reduction in the critical fracture stress at this location. At the same time, the heat transfer between the primary billet shell and the crystallizer at the trough of the deep vibration mark of the billet is unfavorable, resulting in excessive austenite grains in this area, and the slow heat transfer rate will also cause more solute enrichment. When the billet is subjected to external force, it is very easy to form primary microcracks at the weak grain boundary. For high-carbon steel grades that contain many elements such as Ti and B, microalloying elements (Ti, B and other elements) are very easy to combine with C and N in the molten steel to form compounds that precipitate at the grain boundary to form micropores. Under the action of external stress, the micropores are stretched and finally connected together to form microcracks. At the same time, the liquidus temperature of high carbon steel is generally low. When the billet enters the secondary cooling zone, if the cooling system is improper, the billet temperature will fall into the third brittle zone when it enters the straightening section. Under the action of the straightening tensile stress, the inner arc of the billet is prone to form corner transverse cracks. Therefore, it is urgent to study the high carbon steel continuous casting production process to improve the billet qualification rate. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a method for stably controlling the surface quality of high-carbon steel continuous casting billets. The method provided in the present application can improve the surface quality of thick slab high-carbon steel and increase the qualified rate of high-carbon steel casting billets.

[0005] In view of this, the present application provides a method for stabilizing the surface quality of a high carbon steel continuous casting billet, comprising:

[0006] Pouring high carbon steel refined molten steel, wherein the tundish superheat degree of the high carbon steel refined molten steel is 10-25°C;

[0007] After drawing the steel, a protective slag is added, wherein the protective slag includes 28-35wt% CaO, 28-35wt% SiO2, 3-6wt% Al2O3, 13-17wt% Na2O, 1-3.5wt% MgO, 8-12wt% F - , 3~6wt%TC;

[0008] The casting pulling speed is 0.85~1.30m / min;

[0009] The high carbon steel continuous casting billet obtained by pouring is cooled, wherein the width of the high carbon steel continuous casting billet is 1500~1800mm, the water volume of a cold water inner and outer arc crystallizer is 2900~3000L / min, and the water volume of a narrow face crystallizer is 340~360L / min; the width of the high carbon steel continuous casting billet is 2000~2450mm, the water volume of a cold water inner and outer arc crystallizer is 4300~4400L / min, and the water volume of a narrow face crystallizer is 340~360L / min.

[0010] Preferably, the mold slag comprises 28.2-34.2wt% CaO, 28.2-34.2wt% SiO2, 3.5-5.5wt% Al2O3, 1.1-3.1wt% MgO, 13.9-16.9wt% Na2O, 8.1-11.1wt% F - , 3.2~5.2wt% TC.

[0011] Preferably, the mold slag comprises 29-32wt% CaO, 29-32wt% SiO2, 4-5wt% Al2O3, 1.8-2.2wt% MgO, 14-16wt% Na2O, 9-10wt% F - , 3.5~4.5wt% TC.

[0012] Preferably, the pouring section is 200m, the pulling speed is 1.2~1.3m / min, the pouring section is 250mm, the pulling speed is 1.1~1.2m / min, the pouring section is 300mm, and the pulling speed is 0.85~0.90m / min.

[0013] Preferably, the protective slag has an R of 0.98-1.08, a melting point of 997-1070° C., a viscosity of 0.95-1.05 Pa·s, and a water content of ≤0.50%.

[0014] Preferably, the superheat degree of the tundish is 10-25°C in the first heat and 10-20°C in subsequent heats.

[0015] Preferably, during the pouring process, the emergence time of the 200 mm section is 60 to 90 s, the emergence time of the 250 mm section is 70 to 110 s, and the emergence time of the 300 mm section is 70 to 110 s.

[0016] Preferably, the slag consumption of the protective slag is 35-40 kg / t, and the thickness is 13-17 mm.

[0017] Preferably, the high carbon steel continuous casting billet has a width of 1500-2450 mm and a thickness of 200 mm-300 mm.

[0018] Preferably, the pass rate of the high carbon steel continuous casting billet is above 99%.

[0019] The present application provides a method for controlling the surface quality of high-carbon steel continuous casting billets in a stable manner, which pours high-carbon steel refined molten steel, cools the billets after drawing; in the above process, the superheat of the present application is adjusted to 10-20°C, the thickness of the billet is increased, the bulging amount is reduced, the uniformity of the billet shell in the crystallizer is increased, the stress concentration is reduced, and cracks can be prevented during the billet drawing process; the protective slag used after drawing can make the heat transfer and stress more uniform, and the melting point, viscosity, and alkalinity are moderate, the liquid slag flows into the billet shell more continuously and evenly, and the thermal insulation effect is more stable, the crystallization temperature is lower, and the heat transfer can be controlled to achieve the purpose of slow cooling of the billet in the crystallizer to prevent longitudinal cracks; at the same time, a suitable drawing speed is adopted to avoid reducing the consumption of protective slag and making it less likely to cause cracks; and a cold water slow cooling mode can increase the billet shell thickness and effectively reduce the probability of billet cracks. Therefore, this application optimizes and adjusts the above-mentioned process, adopts specific protective slag, and matches appropriate pulling speed, superheat, and a cooling water mode, which effectively improves the quality stability of high-carbon steel continuous casting billets and improves the qualified rate of casting billets. DETAILED DESCRIPTION

[0020] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0021] In order to improve the stable control of the surface quality of high-carbon steel in thick slabs and improve the quality of high-carbon steel ingots, the present application provides a method for stabilizing the surface quality of high-carbon steel continuous casting ingots, which optimizes and adjusts the production process and cooperates with special protective slag to formulate a special pulling speed, superheat, and a cold water slow cooling mode for high-carbon steel, thereby effectively improving the quality stability of high-carbon steel and improving the qualified rate of ingots; specifically, the present application provides a method for stabilizing the surface quality of high-carbon steel continuous casting ingots disclosed in an embodiment of the present invention, comprising:

[0022] Pouring high carbon steel refined molten steel, wherein the tundish superheat degree of the high carbon steel refined molten steel is 10-25°C;

[0023] After drawing the steel, a protective slag is added, wherein the protective slag includes 28-35wt% CaO, 28-35wt% SiO2, 3-6wt% Al2O3, 13-17wt% Na2O, 1-3.5wt% MgO, 8-12wt% F - , 3~6wt%TC;

[0024] The casting pulling speed is 0.85~1.30m / min;

[0025] The high carbon steel continuous casting billet obtained by pouring is cooled, wherein the width of the high carbon steel continuous casting billet is 1500~1800mm, the water volume of a cold water inner and outer arc crystallizer is 2900~3000L / min, and the water volume of a narrow face crystallizer is 340~360L / min; the width of the high carbon steel continuous casting billet is 2000~2450mm, the water volume of a cold water inner and outer arc crystallizer is 4300~4400L / min, and the water volume of a narrow face crystallizer is 340~360L / min.

[0026] In the process of stable control of the surface quality of high-carbon steel continuous casting billets, the present application adjusts some processes in the casting process. The entire process is the same as the casting process in the prior art, and the present application does not make any special limitations on this.

[0027] In the present application, high-carbon steel refined molten steel is poured. The preparation of the high-carbon steel refined molten steel is carried out according to a method well known to those skilled in the art, and the present application does not impose any particular limitation on this. The superheat of the tundish of the high-carbon steel refined molten steel is 10~25℃; the liquidus temperature of high-carbon steel is lower than that of other steel grades. In order to improve the melting efficiency of the protective slag, the superheat of high-carbon steel is generally controlled within 30℃ at present. When the temperature of the molten steel is too high, the temperature difference between the molten steel and the cold water increases, the primary billet shell is thin, the cooling rate of the billet in the crystallizer increases, the thermal stress of the billet shell increases, and at the same time, the heat extracted from the wide surface of the billet is more than the narrow surface of the billet, which makes the corners of the billet cooled unevenly and prone to crack defects; the present application reduces the superheat of the high-carbon steel tundish from 15~30℃ to 10~25℃ by optimizing the process, thereby improving the uniformity of the billet shell in the crystallizer, reducing stress concentration, and significantly reducing corner cracks; further, the superheat is 10~25℃ for the first furnace and 10~20℃ for subsequent furnaces.

[0028] After drawing the steel, protective slag is added. Through the energy spectrum analysis of the components around the crack, a large amount of protective slag elements such as K and Na are found inside the crack, indicating that the crack is generated in the crystallizer and the adaptability of the protective slag is low. The cross-section of the wide and thick plate continuous casting machine is large, the shrinkage stress and bending stress of the billet shell are large, the carbon content of the steel produced by the wide and thick plate is in the peritectic and sub-peritectic reaction range, and the crack sensitivity is high. The protective slag is required to have uniform slag film grains, refined structure, more uniform heat transfer and force, high viscosity, low alkalinity, and more continuous and uniform liquid slag flow between the billet shells. At the same time, it has the characteristics of more stable insulation effect and low crystallization temperature. The optimized protective slag includes: 28~35wt% CaO, 28~35wt% SiO2, 3~6wt% Al2O3, 13~17wt% Na2O, 1~3.5wt% MgO, 8~12wt% F - , 3~6wt% TC; specifically, the protective slag 28.2~34.2wt% CaO, 28.2~34.2wt% SiO2, 3.5~5.5wt% Al2O3, 1.1~3.1wt% MgO, 13.9~16.9wt% Na2O, 8.1~11.1wt% F - , 3.2~5.2wt% TC; more specifically, the protective slag includes 29~32wt% CaO, 29~32wt% SiO2, 4~5wt% Al2O3, 1.8~2.2wt% MgO, 14~16wt% Na2O, 9~10wt% F - , 3.5~4.5wt% TC; more specifically, the protective slag includes 29.17wt% CaO, 29.48wt% SiO2, 4.53wt% Al2O3, 2.08wt% MgO, 16.34wt% Na2O, 10.07wt% F - , 4.05wt% TC. In the present application, the physical and chemical properties of the protective slag are specifically: R is 0.98~1.08, the melting point is 997~1070℃, the viscosity is 0.95~1.05Pa·s, and the moisture content is ≤0.50%; more specifically, R is 0.99, the melting point is 1040℃, the viscosity is 0.90Pa·s, and the moisture content is ≤0.35%.

[0029] The liquid slag thickness of the protective slag is positively correlated with the pulling speed, that is, as the pulling speed increases, the thickness of the liquid slag layer will increase; when the pulling speed is too fast, the consumption of the protective slag decreases, and the thickness of the slag film also decreases, thereby increasing the friction between the copper plate of the crystallizer and the shell of the billet, and easily causing cracks and steel leakage on the surface of the ingot; therefore, the principle of pulling speed control is to ensure that the slag consumption is 35~40kg / t and the liquid slag thickness is 13~17mm when the above-mentioned high carbon steel protective slag is used. During the pouring process, the pulling speed is 0.85~1.30m / min; more specifically: 1.20~1.30m / min for 200mm section, 1.10~1.20m / min for 250mm section, and 0.85~0.90m / min for 300mm section.

[0030] During the pouring process, the emergence time for the 200mm section is 60~90s, the emergence time for the 250mm section is 70~110s, and the emergence time for the 300mm section is 70~110s.

[0031] In the process of producing high carbon steel, the cooling effect of the ingot near the meniscus of the continuous casting crystallizer has an important influence on whether cracks will occur on the surface of the ingot; uneven heat transfer and solidification processes can easily cause depressions and cracks in areas where the ingot shell is thicker or thinner. Statistics of the crack defect locations of high carbon steel show that 90% of the defects appear at the same location of the ingot. Therefore, a slow cooling method using cold water can alleviate the occurrence of crack defects. By gradually reducing the water flow on the wide and narrow sides, the probability of cracks in the ingot can be effectively reduced. Specifically, the width of the high carbon steel continuous casting ingot is 1500~1800mm, the water volume of the cold water inner and outer arc crystallizer is 2900~3000L / min, and the water volume of the narrow side crystallizer is 340~360L / min; the width of the high carbon steel continuous casting ingot is 2000~2450mm, the water volume of the cold water inner and outer arc crystallizer is 4300~4400L / min, and the water volume of the narrow side crystallizer is 340~360L / min.

[0032] The width of the high carbon steel continuous casting billet in the present application is 1500~2450mm, and the thickness is 200~300mm; more specifically, the width of the high carbon steel continuous casting billet is 1500~2450mm, and the thickness is 200mm, 250mm or 300mm.

[0033] Compared with the existing high carbon steel production method of thick plate continuous casting machine, the method for stable control of surface quality of high carbon steel continuous casting billet provided in this application has the following improvements and has the following advantages:

[0034] 1) Changed the conventional idea of ​​melting protective slag at high superheat for high carbon steel, and reduced the superheat from 15~30℃ to 10~20℃, which increased the thickness of the billet shell, reduced the bulging amount, improved the uniformity of the billet shell in the crystallizer, reduced stress concentration, and prevented cracks during the billet drawing process;

[0035] 2) Develop special protective slag for high carbon steel, which has more uniform heat transfer and stress, low melting point, moderate viscosity and alkalinity, and more continuous and uniform flow of liquid slag into the billet shell. At the same time, the thermal insulation effect is more stable, the crystallization temperature is low, and the heat transfer can be controlled to achieve the purpose of slow cooling of the billet in the crystallizer to prevent longitudinal cracking;

[0036] 3) Develop a special casting speed for high carbon steel in wide and thick plate continuous casting machines, which can solve the problem that the consumption of protective slag is reduced and the thickness of slag film is reduced due to inappropriate casting speed, resulting in greater friction between the billet shell and the copper plate, which is prone to cracks;

[0037] 4) Wide and thick plate continuous casting machine high carbon steel one cold water slow cooling mode, this cooling mode can increase the shell thickness of the billet and effectively reduce the probability of cracks in the billet.

[0038] The present invention provides a method for controlling the surface quality of a high-carbon steel continuous casting billet in a stable manner, comprising: pouring high-carbon steel refined molten steel, wherein the tundish superheat degree of the high-carbon steel refined molten steel is 10-25° C.; adding protective slag after drawing the steel, wherein the protective slag comprises 28-35wt% of CaO, 28-35wt% of SiO2, 3-6wt% of Al2O3, 13-17wt% of Na2O, 1-3.5wt% of MgO, 8-12wt% of F - , 3~6wt% TC; the casting pulling speed is 0.85~1.30m / min; the high carbon steel continuous casting billet obtained by casting is cooled, the width of the high carbon steel continuous casting billet is 1500~1800mm, the water volume of a cold water inner and outer arc crystallizer is 2900~3000L / min, and the water volume of a narrow face crystallizer is 340~360L / min; the width of the high carbon steel continuous casting billet is 2000~2450mm, the water volume of a cold water inner and outer arc crystallizer is 4300~4400L / min, and the water volume of a narrow face crystallizer is 340~360L / min. This application optimizes and adjusts the production process, independently develops special protective slag, formulates a special pulling speed, superheat, and cooling water control model for high carbon steel in thick plate continuous casting machines, adjusts the hot billet pressure to improve the roll gap accuracy and other measures, effectively improving the quality stability of high carbon steel and the qualified rate of casting billets. The results show that the qualified rate of high carbon steel continuous casting billets in this application is as high as over 99.9%.

[0039] In order to further understand the present invention, the method for stabilizing the surface quality of high carbon steel continuous casting slabs provided by the present invention is described in detail below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0040] A method for stabilizing the surface quality of thick slab high carbon steel comprises the following steps:

[0041] 1) Before each refined steel liquid leaves the station, determine the steel feeding temperature of the refining process according to the ladle condition and process temperature drop to ensure that the superheat of the tundish is not too high, specifically 10~25℃ for the first furnace and 10~20℃ for subsequent furnaces;

[0042] 2) Press the "Pouring" button on the front operation box to switch to "Pouring Mode". Visually check that the green light of the pouring mode is on, indicating that the mode conversion is correct. At the same time, the main control room requires that the cooling model settings meet the requirements. The billet width is 1500~1800mm, the narrow face water flow is adjusted to 340~360L / min, and the inner and outer arc crystallizer water volume is adjusted to 2900~3000L / min; the billet width is 2000~2450mm, the narrow face water flow is adjusted to 340~360L / min, and the inner and outer arc crystallizer water volume is adjusted to 4300~4400L / min.

[0043] 3) Confirm that there are no foreign objects on the track of the tundish car and that there are no obstacles in the running direction of the tundish car; before driving, visually confirm that the large ladle arm is in the high position and the tundish baking machine is raised to the high position;

[0044] 4) Close the nitrogen ball valve of the gas distribution box and open the argon ball valve to the maximum to convert the nitrogen in the tundish car into argon;

[0045] 5) Press the "up" button on the tundish car operation box, and visually watch the tundish automatically rise to the high position. Use wire to remove the insulation wire blanket wrapped on the surface of the submerged nozzle under the tundish, and visually check that there is no sticky slag on the side holes of the nozzle;

[0046] Use a 1-meter-long iron wire to insert from the side hole of the tundish nozzle, and insert it upward along the inner cavity of the nozzle into the tundish: manually test that the iron wire insertion is smooth, and visually check that no refractory material falls from the side hole of the nozzle;

[0047] 6) After the nozzle is cleaned, press the "pouring position" knob in the operation box, visually observe that the tundish is at a high position, and after running to the "pouring position", turn the knob to the middle position and stop;

[0048] 7) Visually inspect through the baking hole above the tundish car: there is no scattered refractory in the nozzle bowl, close the stopper, close the pressure relief valve of the hydraulic cylinder of the stopper opening and closing mechanism, and the stopper automatically closes: the stopper head and the nozzle bowl are fully engaged without any gap;

[0049] 8) Press the "middle bag down" button, and the middle bag will drop to the "50-70" position displayed on the potentiometer and stop;

[0050] Operate the "lateral movement" and "slow travel" knobs on the tundish car operation box to adjust the centering: north-south centering deviation is ±5mm, east-west centering is ±3mm;

[0051] 9) Place the splash plate on the narrow sides of the upper mouth of the crystallizer to cover the gap between the copper plate corner seam and the upper pressure plate;

[0052] Confirm that the liquid level automatic control is calibrated and the stopper rod control hand box displays normally;

[0053] 10) After the ladle starts pouring, the weight of the molten steel in the tundish reaches 16t, and the tundish pouring starts. Press the "automatic" pouring button on the hand box to start pouring;

[0054] The timing starts after the tundish is poured. According to the emergence time of different sections, the "open" or "close" button is pressed to adjust the steel flow size; the emergence time is controlled at: 60~90 seconds for 200mm section, 70~110 seconds for 250mm and 300mm sections;

[0055] 11) After the molten steel has submerged the side holes of the water inlet, push the protective slag into the crystallizer, check whether there is any steel hanging on the corners and upper gaps of the crystallizer, and use a thin oxygen blowing tube to test whether the liquid surface is crusted; the protective slag includes: 29.17wt% CaO, 29.48wt% SiO2, 4.53wt% Al2O3, 2.08wt% MgO, 16.34wt% Na2O, 10.07wt% F - , 4.05wt% TC; physical and chemical properties: R is 0.99, melting point is 1040℃, viscosity is 0.90Pa·s, moisture ≤0.35%;

[0056] ① For each heat of steel, add 8 to 10 bags of protective slag into the baking box of the automatic slag adding robot;

[0057] ② The automatic slag adding robot moves left and right to automatically add protective slag into the crystallizer according to the set slag adding amount;

[0058] ③ Insert the welding wire into the slag thickness measuring device and extend the welding wire out of the measuring device by 80~100mm;

[0059] ④ On one side of the crystallizer, place the slag thickness gauge flat on the protective slag surface 200~300mm away from the immersion nozzle (avoiding the crystallizer liquid level automatic control sensor) to measure the slag thickness. After the welding wire is inserted into the protective slag, let it stand for 3~5 seconds, and then use a steel ruler to measure the exposed welding wire length (total slag thickness) at 45~65mm; measure the length of the slag sticking part of the welding wire head (liquid slag layer thickness) at 8~15mm;

[0060] ⑤Measure once every 10 minutes, and at the same time, press the automatic slag adding button box "+" and "-" buttons to adjust the slag adding amount according to the measured total slag thickness;

[0061] 12) When the liquid level in the crystallizer rises to 30% of the liquid level display, steel drawing starts automatically. When the liquid level rises to 40%, it does not start. Press the "Start" button of the steel drawing operation box to start steel drawing;

[0062] Through the implementation of the above measures, the first-time inspection pass rate of thick slab high-carbon steel ingots can be increased to 99.9%.

[0063] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0064] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for stabilizing the surface quality of a high carbon steel continuous casting billet, comprising: Pouring high carbon steel refined molten steel, wherein the tundish superheat degree of the high carbon steel refined molten steel is 10-25°C; After drawing the steel, a protective slag is added, wherein the protective slag includes 28-35wt% CaO, 28-35wt% SiO2, 3-6wt% Al2O3, 13-17wt% Na2O, 1-3.5wt% MgO, 8-12wt% F - , 3~6wt%TC; The casting pulling speed is 0.85~1.30m / min; The high carbon steel continuous casting billet obtained by pouring is cooled, wherein the width of the high carbon steel continuous casting billet is 1500~1800mm, the water volume of a cold water inner and outer arc crystallizer is 2900~3000L / min, and the water volume of a narrow face crystallizer is 340~360L / min; the width of the high carbon steel continuous casting billet is 2000~2450mm, the water volume of a cold water inner and outer arc crystallizer is 4300~4400L / min, and the water volume of a narrow face crystallizer is 340~360L / min.

2. The method according to claim 1, characterized in that: The protective slag comprises 28.2-34.2 wt% of CaO, 28.2-34.2 wt% of SiO2, 3.5-5.5 wt% of Al2O3, 1.1-3.1 wt% of MgO, 13.9-16.9 wt% of Na2O, 8.1-11.1 wt% of F - , 3.2~5.2wt% TC.

3. The method according to claim 1 or 2, characterized in that: The mold slag comprises 29-32wt% of CaO, 29-32wt% of SiO2, 4-5wt% of Al2O3, 1.8-2.2wt% of MgO, 14-16wt% of Na2O, 9-10wt% of F - , 3.5~4.5wt% TC.

4. The method according to claim 1, characterized in that: The pouring section is 200m, the pulling speed is 1.2~1.3m / min, the pouring section is 250mm, the pulling speed is 1.1~1.2m / min, the pouring section is 300mm, and the pulling speed is 0.85~0.90m / min.

5. The method according to claim 1, characterized in that The protective slag has an R of 0.98-1.08, a melting point of 997-1070° C., a viscosity of 0.95-1.05 Pa·s, and a moisture content of ≤0.50%.

6. The method according to claim 1, characterized in that The superheat degree of the tundish is 10-25°C for the first heat and 10-20°C for subsequent heats.

7. The method according to claim 1, characterized in that During the pouring process, the emergence time of the 200mm section is 60-90s, the emergence time of the 250mm section is 70-110s, and the emergence time of the 300mm section is 70-110s.

8. The method according to claim 1, characterized in that The slag consumption of the protective slag is 35-40 kg / t, and the thickness is 13-17 mm.

9. The method according to any one of claims 1 to 8, characterized in that The high carbon steel continuous casting billet has a width of 1500-2450 mm and a thickness of 200 mm-300 mm.

10. The method according to any one of claims 1 to 8, characterized in that: The qualified rate of the high carbon steel continuous casting billet is above 99%.