A control method for improving the stability of high carbon alloy steel casting process

Abstract

The present invention relates to a control method for improving the stability of the high-carbon alloy steel smelting and casting process, and belongs to the technical field of alloy steel. In order to solve the problem of lack of effective coordinated control methods among the existing high-carbon alloy steel primary smelting, refining and continuous casting processes, the present invention provides a control method for improving the stability of the high-carbon alloy steel smelting and casting process, including coordinated control of the high-carbon alloy steel converter primary smelting process, refining process and continuous casting process, and the control targets include control of carbon content, control of manganese and chromium content, control of temperature and control of the total smelting and casting cycle. The present invention coordinates and controls multiple key links of the smelting and casting process through control methods such as high carbon drawing, strong deoxidation, uniform stirring, and precise operation, reduces mutual interference between multi-target control accuracies, and improves the stability of the casting process while ensuring precise control of composition, temperature and cycle, and improves the organizational properties and quality stability of high-carbon alloy steel.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy steel, and in particular relates to a control method for improving the stability of a high-carbon alloy steel smelting and casting process. Background Art

[0002] High carbon alloy steel contains 0.60-1.70wt% carbon. After proper heat treatment or cold drawing hardening, it has extremely high strength and hardness, high elastic limit and fatigue limit, acceptable cutting performance and a wide range of applications. The organizational properties and quality stability of high carbon alloy steel products are directly related to the stability control of composition, temperature and cycle during the smelting and casting process. When the main components such as carbon, manganese and chromium in the steel fluctuate, it directly affects the matrix organizational structure and the precipitation type, size and quantity of carbides, and thus affects the final performance of high carbon alloy steel products. When the temperature and cycle of the converter primary refining process and the refining process fluctuate greatly, the continuous casting speed and solidification thermal state of the continuous casting process also change accordingly, resulting in a decrease in process stability, aggravation of metallurgical defects, and even inheritance to the product, resulting in unstable service performance.

[0003] The stability control of high-carbon alloy steel casting process is relatively complex, and attention should be paid to the converter tapping temperature, temperature loss during refining, LF process, VD process temperature control, molten steel composition, impurity elements and inclusions control, and other links and the mutual interference between each link. If the composition of the primary converter tapping steel fluctuates greatly, it will cause a heavy burden on the refining position, affect the production cycle, and thus directly affect the stability of production during the continuous casting process.

[0004] However, the existing processes often only accurately control a single factor in the converter primary refining or refining process, and there is still a lack of effective means to improve process stability through coordinated control among the converter primary refining, refining and continuous casting processes. Summary of the invention

[0005] In order to solve the problem that there is a lack of effective coordinated control method among the existing high-carbon alloy steel primary smelting, refining and continuous casting processes, resulting in process instability and affecting the performance of high-carbon alloy steel products, the present invention provides a control method for improving the stability of the high-carbon alloy steel smelting and casting process.

[0006] The technical solution of the present invention:

[0007] A control method for improving the stability of a high-carbon alloy steel smelting and casting process, comprising coordinated control of a high-carbon alloy steel converter primary smelting process, a refining process and a continuous casting process, wherein the control objectives include control of carbon content, control of manganese and chromium content, control of temperature and control of the total smelting and casting cycle;

[0008] The specific control method of the converter primary smelting process includes correcting the carbon-oxygen product to 0.0023 based on the carbon-oxygen balance principle of molten steel and the high-carbon steel-making conditions; adopting low-high-low three-stage gun position control to perform high carbon drawing operation in the converter primary smelting process to ensure that the steel-making C is ≥ 0.30wt%; the converter tapping temperature is controlled at 1600-1617℃, with a fluctuation of ±8℃;

[0009] The specific control method of deoxidation and alloying during steel tapping from the converter includes adding 10wt% carbon powder to the bottom of the ladle before tapping; adding silicon calcium barium and the remaining carbon powder at the same time when tapping 20 tons of steel; adding aluminum ingots for deep deoxidation at one time according to the end point C component when tapping 20 tons of steel; adding lime when tapping 40 tons of steel; adding refined slag and ferroalloy when tapping 40%, and adding lime again when tapping 50-60% of steel; the cycle of the converter primary smelting process is 32-45 minutes, with a fluctuation of ±7 minutes;

[0010] The molten steel in LF is heated up once, and the composition of the molten steel is fine-tuned by adding lime, fluorite, diffusion deoxidizer silicon carbide and carbon powder; the deoxidizer silicon carbide, carbon powder and Al particles are diffused by power transmission for the second time; the LF process uses double-permeable bags for argon stirring; the temperature of the molten steel leaving the LF station is controlled at 1565-1594℃, with a fluctuation range of ±15℃; the LF cycle is controlled at 45-67min, with an average of 55min and a fluctuation of ±10min;

[0011] The temperature of molten steel leaving the VD station is 1510-1530℃, with a fluctuation of ±10℃; the VD cycle is controlled at 24-32min, with a fluctuation of ±4min;

[0012] The average casting time of a single continuous casting furnace is 55 minutes, with a fluctuation of ±3 minutes.

[0013] Furthermore, the specific control method of the low-high-low three-stage gun position control is as follows:

[0014] From the beginning of blowing for 0 to 6.5 minutes, a low gun position is adopted with a gun height of 1.2m; from the middle stage of blowing for 7 to 10 minutes, a high gun position is adopted with a gun height of 1.4m; from the late stage of blowing for 11 to 14 minutes, a low gun position is adopted with a gun height of 1.2m.

[0015] Furthermore, the amount of silicon, calcium and barium added is 60kg / t, the total amount of carbon powder added is 800kg / t; the amount of aluminum ingot added is 50kg / t; the amount of lime added when 40 tons of steel is tapped is 600kg / t; the amount of refined slag added is 300kg / t; the amount of ferroalloy added is 1400kg / t; the amount of lime added when 50-60% of the steel is tapped is 300kg / t.

[0016] Furthermore, the ferroalloy includes ferrochrome, ferromanganese and ferrosilicon; the order of adding the ferroalloy is ferrochrome → ferromanganese → ferrosilicon.

[0017] Furthermore, 100-300 kg / t of lime, 0-100 kg / t of fluorite, 70-80 kg / t of diffusion deoxidizer silicon carbide, and 30-50 kg / t of carbon powder are added to LF during the primary power transmission.

[0018] Furthermore, 40-50 kg / t of silicon carbide, 20-30 kg / t of carbon powder and 20-30 kg / t of Al particles are added during secondary power transmission of LF.

[0019] Furthermore, the specific control method of argon stirring in the LF process is to use a double-permeable brick ladle, control the argon flow rate at 120-200 L / min before sampling 1 in the LF process, and control it at 180-300 L / min after sampling 1, and the ladle stirring standard is that the diameter of the stirring area is 150-300 mm.

[0020] Furthermore, the white slag time in the LF process is controlled to be ≥20min; in the VD process, the molten steel temperature is controlled to be 1550℃~1565℃, the vacuum degree is ≤67Pa, the holding time is ≥20min, the argon flow rate is controlled to be 100~200NL / min, and the soft blowing static time is>15min.

[0021] Furthermore, the continuous casting speed is 0.65 m / min, the specific water content is 0.2 L / kg, the distribution ratio is 36 / 39 / 25, the first stirring parameter is 200 / 2 Hz, the final stirring parameter is 200A / 8 Hz, and the tension and straightening machine pressure parameters are 2 / 3 / 5 / 5 / 5.

[0022] Furthermore, the chemical composition of the high carbon alloy steel includes, by weight percentage: C: 0.98-1.00%, Si: 0.30-0.55%, Mn: 1.05-1.15%, P≤0.025%, S≤0.035%, Cr: 0.60-0.70%, Ni≤0.25%, Mo≤0.10%, Al: 0.015-0.030%, Cu≤0.40%, Sn≤0.030%, V≤0.030%, Ti: 0.010-0.025%, H≤0.00008%, N: 0.0060-0.0100%, O≤0.0015%, and the rest is Fe and unavoidable impurities.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a control method for improving the stability of the high-carbon alloy steel casting process. Through control methods such as high carbon drawing, strong deoxidation, uniform stirring, and precise operation, multiple key links in the casting process are coordinated and controlled to reduce the mutual interference between the multi-target control precisions, so that the carbon content distribution of the high-carbon alloy steel continuous casting billet can achieve a narrow component control level of no more than ±0.01%, and reach the target range of manganese and chromium. Overall, by ensuring the stability of the raw and auxiliary materials, operations, and processes used in the casting process, slag making, desulfurization, stirring, heating, alloying, etc. in the continuous casting process are completed within the specified time, and the stability of the casting process is improved while ensuring the precise control of the composition, temperature, and cycle. Thereby improving the billet drawing under the constant temperature and constant speed state of continuous casting. The process compliance reaches more than 99.90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a comparison chart of actual carbon content control levels in the high carbon alloy steel continuous casting process of this embodiment and the prior art;

[0026] Figure 2 This is a comparison chart of the manganese and chromium alloying yields during the high carbon alloy steel continuous casting process in this embodiment and the prior art. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0028] Example 1

[0029] A control method for improving the stability of a high-carbon alloy steel smelting and casting process includes coordinated control of a high-carbon alloy steel converter primary smelting process, a refining process and a continuous casting process, wherein control objectives include control of carbon content, control of manganese and chromium content, control of temperature and control of cycle.

[0030] The target values ​​of the chemical composition of the high carbon alloy steel in this embodiment are C: 0.98-1.00%, Si: 0.30-0.55%, Mn: 1.05-1.15%, P≤0.025%, S≤0.035%, Cr: 0.60-0.70%, Ni≤0.25%, Mo≤0.10%, Al: 0.015-0.030%, Cu≤0.40%, Sn≤0.030%, V≤0.030%, Ti: 0.010-0.025%, H≤0.00008%, N: 0.0060-0.0100%, O≤0.0015%, and the rest are Fe and unavoidable impurities.

[0031] The actual measured values ​​are C: 0.98%, Si: 0.35%, Mn: 1.08%, P0.010%, S0.006%, Cr: 0.65%, Ni0.05%, Mo0.02%, Al: 0.022%, Cu0.01%, Sn0.0001%, V0.03%, Ti: 0.014%, H0.00005%, N: 0.0070%, O0.0010%, and the rest are Fe and unavoidable impurities.

[0032] The primary smelting process of the converter in this embodiment adopts oxygen top-blown converter steelmaking method, namely LD steelmaking method, with the ingredients of 85wt% molten iron and 15wt% scrap steel, the scrap steel block size is ≤600mm, the molten iron composition is guaranteed to be P≤0.12%, Si0.30~0.65%, S≤0.045%, and the molten iron temperature is ≥1200℃, so that it releases maximum heat energy, which can ensure the stability of high-drawn carbon in the converter, maximize the metal recovery rate, and reduce the consumption of steel materials.

[0033] The converter primary smelting process adopts low-high-low three-stage gun position control to perform high carbon drawing operation to ensure that the steel C ≥ 0.30wt%.

[0034] The specific control method of the low-high-low three-stage gun position control is as follows:

[0035] 0-6.5min after blowing, a low lance position is used with a lance height of 1.2m; a lower lance position can ensure rapid heating and slagging, increase the ferrous oxide content, and rapidly dephosphorize;

[0036] In the middle period of blowing for 7 to 10 minutes, a high lance position of 1.4m is used. When the lance position is raised, carbon is strongly oxidized and the slag and steel in the molten pool in the furnace are stirred violently, so as to avoid accelerated decarburization, slag drying and splashing caused by a too low lance position, which will affect the phosphorus and desulfurization effects.

[0037] In the later stage of blowing, 11 to 14 minutes, a low lance position is adopted with a lance height of 1.2m; a lower lance position can enhance stirring, prevent reduction reaction and adjust the fluidity of the slag.

[0038] The control parameters of oxygen flow during blowing are as follows: working oxygen pressure 0.81Mpa, oxygen flow 18400Nm 3 / h, oxygen supply intensity 3.0Nm 3 / (t·min).

[0039] After the gun position is optimized in this embodiment, the slag has better fluidity, the smelting is stable, and the carbon content of the steel can be not less than 0.30wt%.

[0040] It can be seen from the carbon-oxygen balance that within the steelmaking temperature range, the product of [%C]·[%O] in the molten pool is basically a constant. At 1600°C and Pco=1 atmosphere, the theoretical value is about 0.0025. In fact, the carbon-oxygen concentration curve is close to the theoretical value only when [%C] is less than 0.1%. When [%C] is greater than 0.2%, the carbon-oxygen product increases slightly as [C%] increases. Since the measured data in the high-carbon region deviates greatly from the theoretical value, this embodiment makes corrections based on the carbon-oxygen product of the high-carbon steel-making condition, and corrects the carbon-oxygen product when [%C] is greater than 0.3% to 0.0023. This not only avoids the problem of error in reporting the carbon content of steel according to the theoretical value of carbon-oxygen product, but also solves the problem of hysteresis in real-time detection. This embodiment improves the accuracy and stability of the carbon and oxygen content of converter steel-making by correcting the carbon-oxygen product of the high-carbon steel-making condition.

[0041] Since the high carbon drawing process is used in the converter primary refining process, the carbon content fluctuates greatly, and its unstable control directly affects the temperature of the molten steel. At the same time, the temperature of the molten steel will fluctuate significantly if the blowing intensity or time changes slightly. By strictly controlling the composition and temperature of the molten iron, as well as the gun position, flow rate and time of the converter primary refining process, combined with the correction and application of the carbon-oxygen balance law, this embodiment stably controls the converter tapping temperature at 1600-1617°C, with a fluctuation of ±8°C.

[0042] In this embodiment, the C content of the steel tapped from the converter is above 0.30wt%, the tapping temperature is above 1600°C, and the carbon increase operation is performed according to the carbon content actually measured in the steel tapped from the converter.

[0043] The specific control method of carburization, deoxidation and alloying during steel tapping in the converter of this embodiment is as follows:

[0044] Before tapping, add 10wt% carbon powder to the bottom of the ladle;

[0045] When 20 tons of steel is tapped, 60 kg / t of silicon, calcium and barium are added, and the remaining carbon powder is added at the same time. The total amount of carbon powder added in the two times is 800 kg / t.

[0046] When 20 tons of steel is tapped, 50kg / t of aluminum ingot is added at one time for deep deoxidation according to the final C component;

[0047] When 40 tons of steel is tapped, 600 kg / t of lime is added to ensure good slagging and no crusting;

[0048] When 40% of the steel is tapped, 300kg / t of refined slag and 1400kg / t of ferroalloy are added. The order of adding ferroalloy is ferrochrome → ferromanganese → ferrosilicon.

[0049] When 50-60% of the steel is tapped, add 300kg / t of lime.

[0050] The refined slag of this embodiment is composed of the following components in percentage by mass:

[0051] CaO 45%, MgO 4.2%, Fe2O3 0.3%, Al2O3 41%, SiO2 1.4% and TiO2 0.02%.

[0052] The composition of carbon powder varies little between batches, with carbon content fluctuating no more than 0.5%, sulfur content fluctuating no more than 0.02%, ash content fluctuating no more than 1.0%, moisture content fluctuating no more than 0.05%, and particle size fluctuating no more than 3%. The key indicators are relatively stable. The alloy is baked in advance to reduce the heat loss of molten steel when in contact with molten steel, and deep deoxidation is done to maximize the alloy yield. The composition of the main alloying elements in different batches of ferroalloys is required to be relatively stable, the manganese alloy content in ferromanganese alloy fluctuates no more than 0.8%, and the carbon content fluctuates no more than 0.3%; the chromium content in ferrochromium alloy fluctuates no more than 0.7%, and the carbon content fluctuates no more than 0.3%, and the impurity element sulfur content does not exceed 0.01% and 0.03% respectively, providing a raw material basis for the precise control of manganese and chromium components.

[0053] During the steel-making process, C powder is first added to the steel to react with oxygen in the molten steel to generate CO2, and then aluminum ingots are added to the steel for precipitation deoxidation. Alloying is performed when 40% of the steel is tapped to ensure that the aluminum-oxygen reaction is complete. After deep deoxidation, alumina fully floats and the alloy is well deoxidized when added, which maximizes the alloy yield and accuracy and reduces production costs. Ferroalloys are added during the steel-making process, and the alloy elements are dissolved evenly, eventually reaching the target range of manganese and chromium. The carbon, manganese, and chromium contents of the finished steel in the order of adding materials do not exceed ±0.01%, ±0.02%, and ±0.02%, respectively, reaching 99.5%, 99.3%, and 99.3%.

[0054] This embodiment ensures that the cycle of the converter primary smelting process is 32 to 45 minutes with a fluctuation of ±7 minutes by ensuring the stability of the molten iron weight, temperature and composition, the amount of scrap steel added, the size and time, the gas flow rate and stirring time in the converter primary smelting process; the slag composition and dosage are accurate, and the timing and method of slag making are constant.

[0055] The LF refining process of high carbon steel is carried out through slag-metal reaction for deoxidation, desulfurization, alloying and temperature control. The control process of different links also has an important impact on the LF refining tapping temperature. In order to improve the temperature stability of LF molten steel, the parameters such as heating, stirring, slag amount and alloy material composition are strictly controlled on site.

[0056] In order to improve the stability of the LF furnace refining time, it is necessary to control the stability of the incoming steel weight, temperature and composition; the stability of the gas flow and stirring time; the accuracy of the slag composition and dosage; the constancy of the slag making timing and method; the stability of the heating efficiency, method and time; and the constancy of the alloy material composition and addition method.

[0057] In this embodiment, the LF is in place and the molten steel is heated once. When the temperature of the molten steel is greater than the liquidus temperature by 40°C, that is, greater than 1530°C, the power supply is stopped to measure and sample 1 to determine the composition of the steel. The composition of the molten steel is fine-tuned to ensure that the composition is within the internal control range, and at the same time, the S element is controlled to be ≤0.003%. At this time, the harmful elements in the steel are the least. Lime 100-300kg / t, fluorite 0-100kg / t, diffusion deoxidizer silicon carbide 70-80kg / t, and carbon powder 30-50kg / t are added.

[0058] The secondary power transmission controls the molten steel temperature to 1590℃, and the secondary power transmission diffusion deoxidizer uses 40-50kg / t of silicon carbide, 20-30kg / t of carbon powder, and 20-30kg / t of Al particles.

[0059] In this embodiment, argon stirring adopts a double-permeable ladle. The specific control method of argon stirring is to control the argon flow rate at 120-200 L / min before sampling 1 and at 180-300 L / min after sampling 1. The ladle stirring standard is that the diameter of the stirring area is 150-300 mm.

[0060] In this embodiment, the argon stirring mode is changed from a single hole to a double hole. After increasing the argon flow rate, the mixing time is shortened, the LF argon blowing stirring and mixing time is reduced by 1.2 minutes, and the refining cycle fluctuation is reduced from ±13 minutes to ±10 minutes.

[0061] In this embodiment, the white slag time is controlled to be ≥20min.

[0062] This embodiment strictly controls parameters such as heating, stirring, slag amount and alloy material composition. At the same time, by optimizing the stirring method and parameters, the stability of the slag surface can be ensured, the molten steel temperature is more uniform, and the temperature accuracy of the subsequent process is guaranteed. The LF molten steel temperature is controlled at 1565-1594°C, with a fluctuation range of ±15°C. Under the premise of ensuring precise control of composition and temperature, the LF process cycle is 45-67min, the average is 55min, and the fluctuation is ±10min.

[0063] The VD process of high carbon steel in this embodiment is mainly used for degassing, desulfurization, inclusion floating, alloying, uniform temperature, etc. After VD, the molten steel is directly transported to the continuous casting span casting, so the temperature control of VD leaving the station is the most critical. Since there is no heating equipment and no sufficient chemical reaction heat in the VD process, it is mainly based on cooling.

[0064] In order to control the temperature stability of the VD process, the VD steel composition and temperature, vacuum degree and vacuum time, argon flow rate and stirring time, calcium treatment process, etc. are strictly controlled. In the VD process, the molten steel temperature is controlled at 1550℃~1565℃, the vacuum degree is ≤67Pa, the holding time is ≥20min, the argon flow rate is controlled at 100~200NL / min, and the soft blowing static time is >15min, which effectively controls the floating of inclusions; calcium treatment uses silicon calcium wire, and the dosage is 1~1.5m / t.

[0065] The temperature of high carbon steel VD molten steel leaving the station is 1510~1530℃, with a fluctuation of ±10℃. Through the research on raw materials, process and operation, the VD cycle is controlled at 24~32min, with a fluctuation of ±4min.

[0066] The continuous casting process of this embodiment uses a five-machine five-stream 250*280 large square billet continuous casting machine for production. A total of 3 rows of cooling rings are set for full roller cooling, and 2 nozzles are set on each surface. The opening angle of the nozzle is 80°C on the wide side and 70°C on the narrow side, which can cover the entire end face of the casting billet. The cooling method is full water cooling.

[0067] Continuous casting speed: 0.65m / min, specific water volume: 0.2L / kg, distribution ratio 36 / 39 / 25, first stirring parameter 200 / 2Hz, final stirring parameter 200A / 8Hz, tension and leveling machine pressing parameters 2 / 3 / 5 / 5 / 5. The crystallizer copper tube uses 0 to 200 fires, no Cr coating falls off above the meniscus, the copper tube taper is 1.24% / m, the crystallizer water gap is uniform 0.4±0.2mm, and the foot roller arc is -0.4mm.

[0068] The parameters of this embodiment are highly matched and the pouring time is effectively controlled. The average pouring time of a single continuous casting furnace is 55 minutes, with a fluctuation of ±3 minutes, thereby further ensuring the stability of the casting process of the ingot.

[0069] The carbon content distribution control level of this embodiment and the prior art high carbon alloy steel is tested and the comparison results are as follows: Figure 1 shown.

[0070] For high carbon steel with a target carbon content between 0.98% and 1.00%, high carbon drawing + strong deoxidation + strict temperature control and other measures are adopted. The qualified rate of carbon content in the primary smelting process of high carbon steel converter is 100%, and the difference between the target carbon content and the actual carbon content is less than 0.01% in 99.5%, while the carbon content distribution of high carbon steel in the past years has exceeded ±0.03%. Overall, the present invention has achieved a narrow composition control level of no more than ±0.01% for the carbon content distribution of high carbon alloy steel through strict control of multiple key links in the smelting process.

[0071] The alloying yield control level of this embodiment and the prior art high carbon alloy steel is tested, and the comparison results are as follows: Figure 2 shown.

[0072] The alloying process has a direct impact on the accuracy of alloying element content and its cost control. Figure 2 As shown, the recovery rates of manganese and chromium elements during the alloying process of high carbon steel are relatively stable, which are 90%±1% and 97%±1% respectively, which is beneficial for accurately controlling the content of the two elements.

Claims

1. A control method for improving the stability of high carbon alloy steel casting process, characterized in that: It includes coordinated control of the converter primary smelting process, refining process and continuous casting process of high carbon alloy steel. The control targets include the control of carbon content, manganese and chromium content, temperature and the control of the total smelting and casting cycle. The specific control method of the converter primary smelting process includes correcting the carbon-oxygen product to 0.0023 based on the carbon-oxygen balance principle of molten steel and the high-carbon steelmaking conditions; adopting low-high-low three-stage gun position control to perform high carbon drawing operation in the converter primary smelting process to ensure that the steel tapping C ≥ 0.30wt%; the converter tapping temperature is controlled at 1600~1617℃, with a fluctuation of ±8℃; The specific control method of deoxidation and alloying during steel tapping from the converter includes adding 10wt% of the total carbon powder added to the bottom of the ladle before steel tapping; adding silicon calcium barium and the remaining carbon powder at the same time when 20 tons of steel are tapped; adding aluminum ingots for deep deoxidation at one time according to the end point C component when 20 tons of steel are tapped; adding lime when 40 tons of steel are tapped; adding refined slag and ferroalloy when 40% of the steel is tapped, and adding lime when 50-60% of the steel is tapped; the cycle of the converter primary smelting process is 32-45 minutes, with a fluctuation of ±7 minutes; LF conducts a power transmission to heat the incoming molten steel, fine-tunes the composition of the molten steel, and adds lime, fluorite, diffusion deoxidizer silicon carbide and carbon powder; a second power transmission is performed to add diffusion deoxidizer silicon carbide, carbon powder and Al particles; the LF process uses a double-permeable bag for argon stirring; the temperature of the molten steel leaving the LF station is controlled at 1565~1594℃, with a fluctuation range of ±15℃; the LF cycle is controlled at 45~67min, with an average of 55min and a fluctuation of ±10min; The temperature of molten steel leaving the VD station is 1510~1530℃, with a fluctuation of ±10℃; the VD cycle is controlled at 24~32min, with a fluctuation of ±4min; The average casting time of a single continuous casting furnace is 55 minutes, with a fluctuation of ±3 minutes; continuous casting speed: 0.65m / min, specific water volume: 0.2 L / kg, distribution ratio 36 / 39 / 25, first stirring parameter 200A / 2Hz, final stirring parameter 200A / 8Hz, and the tension and straightening machine pressure parameters are 2 / 3 / 5 / 5 / 5.

2. A control method for improving the stability of high carbon alloy steel casting process according to claim 1, characterized in that: The specific control method of the low-high-low three-stage gun position control is as follows: From the beginning of blowing for 0 to 6.5 minutes, a low gun position is adopted with a gun height of 1.2m; from the middle stage of blowing for 7 to 10 minutes, a high gun position is adopted with a gun height of 1.4m; from the late stage of blowing for 11 to 14 minutes, a low gun position is adopted with a gun height of 1.2m.

3. A control method for improving the stability of high carbon alloy steel casting process according to claim 1 or 2, characterized in that: The amount of silicon, calcium and barium added is 60kg / t, the total amount of carbon powder added is 800kg / t; the amount of aluminum ingot added is 50kg / t; the amount of lime added when 40 tons of steel is tapped is 600kg / t; the amount of refined slag added is 300kg / t; the amount of ferroalloy added is 1400kg / t; the amount of lime added when 50-60% of the steel is tapped is 300kg / t.

4. A control method for improving the stability of high carbon alloy steel casting process according to claim 3, characterized in that: Ferroalloys include ferrochrome, ferromanganese and ferrosilicon; the order of adding ferroalloys is ferrochrome → ferromanganese → ferrosilicon.

5. A control method for improving the stability of high carbon alloy steel casting process according to claim 4, characterized in that: When LF transmits power once, 100~300kg / t of lime, 0~100kg / t of fluorite, 70~80kg / t of diffusion deoxidizer silicon carbide, and 30~50kg / t of carbon powder are added.

6. A control method for improving the stability of high carbon alloy steel casting process according to claim 5, characterized in that: When LF is used for secondary power transmission, 40~50kg / t of silicon carbide, 20~30kg / t of carbon powder and 20~30kg / t of Al particles are added.

7. A control method for improving the stability of high carbon alloy steel casting process according to claim 6, characterized in that: The specific control method of argon stirring in the LF process is: using a double-permeable brick ladle, the argon flow rate is controlled at 120~200L / min before sampling 1 in the LF process, and is controlled at 180~300L / min after sampling 1, and the ladle stirring standard is that the diameter of the stirring area is 150~300mm.

8. A control method for improving the stability of high carbon alloy steel casting process according to claim 7, characterized in that: The white slag time in the LF process is controlled to be ≥20min; in the VD process, the molten steel temperature is controlled to be 1550℃~1565℃, the vacuum degree is ≤67Pa, the holding time is ≥20min, the argon flow rate is controlled at 100~200NL / min, and the soft blowing static time is >15min.

9. A control method for improving the stability of high carbon alloy steel casting process according to claim 8, characterized in that: The chemical composition of high carbon alloy steel includes by weight percentage: C: 0.98~1.00%, Si: 0.30~0.55%, Mn: 1.05~1.15%, P≤0.025%, S≤0.035%, Cr: 0.60~0.70%, Ni≤0.25%, Mo≤0.10%, Al: 0.015~0.030%, Cu≤0.40%, Sn≤0.030%, V≤0.030%, Ti: 0.010~0.025%, H≤0.00008%, N: 0.0060~0.0100%, O≤0.0015%, and the rest are Fe and unavoidable impurities.

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