A method for producing a ship plate steel a36

Abstract

The application discloses a production method of ship plate steel A36 and belongs to the technical field of steel smelting. 电弧总平均长度 With LF 进站渣厚 And the maximum F 氩气流量 Value relationship design LF required slag input, according to the argon station sampling W 氩站C %, W 氩站Si %, and W 氩站S %, the amount of ferrosilicon powder is calculated. The problem of the time lag of the converter tapping alloying and slag washing, the poor melting of alloy slag, the unstable LF arc flow, the serious nitrogen increase, the mismatch of slag thickness and arc length, argon, secondary oxidation and nitrogen increase during the LF high-power long-arc power transmission is solved, so that the ship plate steel A36 obtained by smelting is more efficient and has better quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel smelting, in particular to a production method of ship plate steel A36. BACKGROUND

[0002] A36 belongs to medium-carbon ship plate steel and is widely used in shipbuilding industry. The product requires small strength fluctuation range, small anisotropy, good cold bending, impact and welding performance, and various performance indexes meet the requirements of various ship classification societies and users. The production process of ship plate steel A36 provided by the related technology is as follows: high furnace molten iron→(mixing furnace) 120t converter smelting→LF refining→RH refining→slab continuous casting machine continuous casting. The smelting process card stipulates that the range of C is 0.14%-0.17%, the range of Si is 0.12%-0.40%, the range of Mn is 1.25%-1.40%, the range of P is ≤0.020%, the range of S is ≤0.015%, the range of Als is 0.015%-030%, and the range of V is 0.030%-0.060%. The internal control of C is 0.15%-0.17%, the internal control of Si is 0.12%-0.30%, the internal control of Mn is 1.25%-1.35%, the internal control of P is ≤0.020%, the internal control of S is ≤0.015%, the internal control of Als is 0.015%-0.25%, and the internal control of V is 0.030%-0.060%. The target of C is 0.16%, the target of Si is 0.20%, the target of Mn is 1.29%, the target of P is ≤0.020%, the target of S is ≤0.015%, the target of V is 0.040%, and the target of Als is 0.020%. The converter tapping alloying and slag washing: 3.1-3.3kg high-carbon ferromanganese per ton of steel, 13.5-13.7kg silicon manganese per ton of steel, 0.7-0.9kg aluminum iron per ton of steel, 0.75-0.77kg vanadium iron per ton of steel, 3.9-4.1kg lime per ton of steel, 1.9-2.1kg bauxite per ton of steel are added at 1 / 3 tapping; the LF slagging material: 3.3-5.8kg lime per ton of steel, 0-1.8kg fluorite ball per ton of steel, and 0.57-0.0.59kg aluminum slag ball per ton of steel; the LF deoxidizing material: 0-1.5kg silicon carbide per ton of steel or 0-1.5kg silicon iron powder per ton of steel.

[0003] However, in actual smelting, the converter tapping alloying and slag washing time lag, the alloy slag material is not melted well, which causes the LF arc flow to be unstable and easy to increase nitrogen, the amount of slag material in the LF refining process does not match the smelting process, which leads to poor deoxidization and serious nitrogen increase.

[0004] Therefore, it is necessary to provide a production method of ship plate steel A36. SUMMARY

[0005] The present application aims to overcome the defects of the prior art and provide a production method of ship plate steel A36.

[0006] The present application solves its technical problems by adopting the following technical solutions.

[0007] The present application provides a production method of ship plate steel A36, comprising the following steps:

[0008] The converter is tapped to deoxidize and alloy the molten steel and perform slag washing treatment;

[0009] After tapping, sampling is performed at the argon station to measure W 氩站C %, W 氩站Si % and W氩站S %;

[0010] LF refining is performed: the molten steel is measured at the station to measure LF 进站温度 and LF 进站渣厚 ;

[0011] First power is used for preheating and temperature rising, argon is introduced, lime, fluorite and slag surface deoxidizer aluminum slag ball are added to form slag and deoxidize, wherein the addition amount of lime and fluorite is calculated according to the actual smelting L 电弧总平均长度 , LF 进站渣厚 and the maximum F 氩气流量 value occurring before the end of smelting;

[0012] After preheating, second power is used for main heating and temperature rising, argon is continuously introduced, and silicon iron powder is added for subsequent slag surface deoxidization, wherein the addition amount of silicon iron powder is calculated according to the sampling amount at the argon station;

[0013] After slagging, power is stopped, argon is stirred, sampling 1 is performed, the analysis result is analyzed, the molten steel composition content is adjusted according to the target composition requirement, then the temperature is raised to feed aluminum wire, argon is blown from the bottom to stir, sampling 2 is performed again, the analysis result is analyzed, until the molten steel composition meets the target composition, then the molten steel is tapped;

[0014] The molten steel is subjected to RH vacuum treatment to obtain ship plate steel A36.

[0015] The present application has the following beneficial effects:

[0016] The production method of ship plate steel A36 provided by the present application optimizes the smelting process, the addition amount of lime and fluorite is calculated according to the actual smelting L 电弧总平均长度 , LF 进站渣厚 and the maximum F 氩气流量 value occurring before the end of smelting, the addition amount of silicon iron powder is calculated according to the sampling at the argon station, the problems of time lag of alloying and slag washing of the converter tapping, poor melting of alloy slag, unstable LF arc current and easy nitrogen increase are solved. When the LF high-power long-arc power is sent, the slag thickness, arc length and argon gas are not matched, causing serious secondary oxidation and nitrogen increase, so that the smelting efficiency of ship plate steel A36 is higher and the quality is better. DETAILED DESCRIPTION

[0017] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not indicated, the conventional products that can be obtained by market purchase are adopted.

[0018] In order to solve the problems of the time lag of converter tapping alloying and slag washing, poor melting of alloy slag, and easy nitrogen increase caused by unstable LF arc flow. When the LF high-power long-arc power is sent, the slag thickness, arc length and argon gas are not matched, which causes serious secondary oxidation and nitrogen increase. The present application provides a production method of ship plate steel A36. According to the calculation, the adding amount of lime, fluorite and ferrosilicon powder in the LF refining process is obtained, so that the deoxidation and desulfurization in the LF refining process is more accurate, and the deoxidation and desulfurization effect is better.

[0019] The production method of ship plate steel A36 provided by the embodiments of the present application will be described in detail below.

[0020] The embodiments of the present application provide a production method of ship plate steel A36, which comprises the following steps:

[0021] S1: The converter end point C is controlled at 0.07%-0.08%, the O is controlled at 500-700ppm, the P is controlled at ≤0.015%, and the tapping temperature is controlled at 1610±20℃.

[0022] S2: The converter tapping alloying and slag washing treatment are performed.

[0023] The alloying adding time is: 3.1-3.3kg high-carbon ferromanganese per ton of steel, 13.5-13.7kg silicon manganese per ton of steel, 0.7-0.9kg aluminum iron per ton of steel, and 0.75-0.77kg vanadium iron per ton of steel are added at 1 / 6 of the tapping.

[0024] The slag washing material adding time is: 3.9-4.1kg synthetic slag per ton of steel, preferably 4kg synthetic slag per ton of steel, and 1.9-2.1kg lime per ton of steel, preferably 2kg lime per ton of steel are added at 1 / 2 of the tapping. Among them: the synthetic slag adding amount Wsynthetic slag= Wbauxite x bauxite (Al2O3) % ÷ synthetic slag (Al2O3) %. The lime adding amount Wlime=[Wlime x lime (CaO) % - Wsynthetic slag x synthetic slag (CaO) %] ÷ lime (CaO) %.

[0025] It is worth noting that: the alloying is performed at 1 / 6 of the tapping, argon gas is introduced at 55-60Nm 3 / h, and after the alloying is completed, it is immediately adjusted to 38-42Nm 3h. Replace part of lime and bauxite with synthetic slag of low melting point, at 1 / 2 tapping, to determine good melting effect.

[0026] When tapping C is less than 0.07%, manually add carbon powder for pre-deoxidation and exhaust (use CO bubbles generated by deoxidation of molten steel to carry out denitrification), while increasing carbon content, to ensure that the carbon content reaches 0.12%-0.14% at station C, preferably 0.13%. 碳粉 = 0.07 x (LF 到站C含量 - converter 出钢C含量 ) kg / ton of steel. In production practice, it is found that the carbon powder yield is about 60%, i.e. 40% for exhaust and 60% for carbon increase.

[0027] S3: After tapping, adjust the argon flow to 5-10 Nm 3 / h in soft blowing state to prevent the molten steel from being exposed.

[0028] Sample at the argon station to obtain W 氩站C %, W 氩站Si %, and W W氩站S %.

[0029] S4: Perform LF refining, including the following steps:

[0030] S41: Measure the temperature at the inlet to obtain LF 进站温度 .

[0031] S42: Measure the slag thickness with an iron pipe at the inlet to obtain LF 进站渣厚 (mm). When the slag thickness at the inlet is 1 mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . From the further calculation in step S2, it is obtained that the converter slag washing slag weight G 洗渣 = 4 + 2 = 6 (kg of slag / ton of steel). When the slag thickness is 1 mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6 ÷ LF 进站渣厚 (kg of slag / ton of steel).

[0032] The slag thickness at the inlet is not a fixed value, and it is affected by the number of ladle heats. When the converter slag washing slag weight is the same, the older the ladle is and the thinner the ladle wall is, the smaller the slag thickness is. Therefore, the most accurate current measurement should be used.

[0033] S43: Adjust the dust hood valve to 85% to maintain a slightly positive pressure state in the furnace to reduce the absorption of air (mainly N2) by the molten steel during the smelting process. Use a transformer with 11 stages (preheating position), and introduce argon at a flow rate of 35-40 Nm 3 / h (preferably 38 Nm 3(h) Power on for 5 minutes to form slag, then successively add lime, fluorite and aluminum slag balls as deoxidizer on the slag surface.

[0034] The calculation method for the addition of lime and fluorite slag is as follows: In production practice, it has been found that using a transformer with 4 stages (main heating setting) and introducing 35-40 Nm of argon gas is optimal. 3 / h (preferred 38Nm) 3 When energized ( / h), the average arc length L1 弧长 The value is 153±2 (mm) (preferably 153 (mm)). The higher the argon gas flow rate, the greater the electrode shaking. For every 5 Nm increase in argon gas flow rate... 3 / h, the electrode is prone to licking the molten steel, resulting in an average arc length L2 弧长 A fluctuation of 1 mm means that for every 1 Nm increase in the argon gas flow rate... 3 / h increase in average arc length L2 弧长 =1 ÷ 5 = 0.2 (mm). Let the argon flow rate range be F (argon flow rate), and the baseline value of the introduced argon flow rate be 38 Nm. 3 / h, then, the average length L2 of the arc fluctuation caused by the argon flow rate. 弧长 = (F argon flow rate - 38) × 0.2 (mm).

[0035] Furthermore, the actual average length L of the electric arc in smelting 弧长 =[L1 弧长 +L2 弧长 ] = [153 + (F 氩气流量 -38)×0.2]. Additional slag thickness D2 is required. 补充渣厚 =L 弧长 -LF 进站渣厚 =(L1) 弧长 +L2 弧长 )-LF 进站渣厚 =[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚 The amount of slag that still needs to be added, G 补充渣量 =D2 补充渣厚 ×g1=D2 补充渣厚 ×(6÷LF 进站渣厚 )=[(L1 弧长 +L2 弧长 )-LF 进站渣厚 ]×(6÷LF 进站渣厚 )={[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(6÷LF 进站渣厚 In practice, it was found that a lime:fluorite ratio of 3.5:1 resulted in excellent slag fluidity and submerged arc performance. Therefore, further research was conducted, with the lime replenishment amount set to X. 石灰The amount of fluorite replenished is Y. 萤石 X 石灰 +Y 萤石 =G 补充渣量 X 石灰 Y 萤石 =3.5:1, equivalent to 4.5Y 萤石 =G 补充渣量 Y 萤石 ={[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(6÷LF 进站渣厚 )÷4.5(kg). X 石灰 ={[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(6÷LF 进站渣厚 )÷4.5×3.5(kg).

[0036] It is worth noting that the F argon flow rate can be adjusted arbitrarily according to the current smelting needs, and the actual total average arc length is based on the maximum F argon flow rate that occurs before the end of smelting.

[0037] Specific methods of addition include: adding Y sequentially during the power-on process. 萤石 X 石灰 And aluminum slag balls 1.2 kg / ton of steel; of which, Y 萤石 X 石灰 Aluminum slag balls are added in batches, and each batch of YY 萤石 X 石灰 When mixed with aluminum slag balls, take 5 batches as an example, the amount of lime in each batch is X. 石灰 / 5 (kg / ton of steel), the amount of fluorite in each batch is Y 萤石 The dosage is 5 kg / ton of steel, and the amount of aluminum slag balls in each batch is 0.24 kg / ton of steel. In this way, the deoxidizer can be evenly distributed on the slag surface through small-batch addition, so as to achieve a good deoxidation effect.

[0038] S44: Preheating complete, switch to transformer speed 4 and simultaneously introduce argon gas at 35-40 Nm. 3 Power continues to be supplied at / h for main heating and temperature increase. W is obtained from step S3. 氩站C % and W 氩站Si %,and W氩站S %, first according to W 氩站Si % Ferrosilicon powder is added for subsequent slag surface deoxidation; specifically including:

[0039] When W 氩站Si When the silicon content is ≥0.20%, do not add ferrosilicon powder (to avoid exceeding the silicon content standard). Add 0.08 kg / ton of aluminum slag balls every 5 minutes of heating for diffusion deoxidation. 铝渣球加入量= 0.08 x (T 加热 ÷ 5) kg / ton of steel.

[0040] When W 氩站Si < 0.20%, according to the difference ΔWSi% of silicon content, add ferrosilicon powder according to 0.20% - W 氩站Si % of the steel, so the amount of ferrosilicon powder added G 硅铁粉1 = (0.20% - W 氩站Si %) / 0.01% x 0.21 kg / ton of steel.

[0041] When W 氩站S > 0.15%, strengthen diffusion deoxidation. According to the difference ΔWS% of sulfur content, add ferrosilicon powder according to W 氩站S % - 0.015%, so the amount of ferrosilicon powder added G 硅铁粉2 = (W 氩站S % - 0.015%) / 0.001% x 0.07 kg / ton of steel.

[0042] When W 氩站C < 0.08%, the liquid steel dissolves too much oxygen, according to the difference ΔWC% of carbon content, add ferrosilicon powder according to 0.08% - W 氩站C % of the steel, so the amount of ferrosilicon powder added G 硅铁粉3 = (0.08% - W 氩站C %) / 0.01% x 0.14 kg / ton of steel.

[0043] From the above conditions, W 氩站Si < 0.20% or W 氩站S > 0.15% or W 氩站C < 0.08%, the total amount of ferrosilicon powder added G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20% - W 氩站Si %) / 0.01% x 0.21 + (W 氩站S % - 0.015%) / 0.001% x 0.07 + (0.08% - W 氩站C %) / 0.01% x 0.14 kg / ton of steel.

[0044] S5: power to the liquid steel temperature > 1564°C, power off, argon is introduced 60 Nm 3Strong stirring for 2 min, sample 1, sticky slag color observation. The composition 1 is obtained. The sticky slag is preferably thin white slag. When the thin white slag is not reached, silicon iron powder 0.07-0.0.21 kg / ton of steel is put in until the slag reaches the target. Fe 0.3%-0.6%, MnO 0.2%-0.4%, S 0.6%-0.8%, MgO 4%-7%, P2O5 0.05-0.07%, basicity R 4.3-5.8, the steel liquid deoxidation and desulfurization effect is best.

[0045] S6: Continue main heating, according to the results of composition 1, adjust [C], [Si] and [Mn] in the steel liquid to the target 0.16%, 0.20% and 1.29% respectively.

[0046] S7: When the steel liquid is heated to the preset requirement 1623±5℃, the steel liquid is fed with aluminum wire under white slag state 10min before leaving the station, and [Als] is adjusted to 0.030%-0.033%(preferably 0.030%) according to the results of composition 1. After feeding the aluminum wire, argon is blown in for 20-25Nm 3 / h(preferably 22Nm 3 / h) for 10min, so that a small amount of Al2O3 inclusions in the steel liquid can fully float up.

[0047] S8: Sample 2, temperature measurement. The molten steel leaves the station.

[0048] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time≥13min, high vacuum time≥10min, pure degassing time≥7min. Vacuum degree≤0.266KPa, circulation gas flow 40-72Nm 3 / h(preferably 72Nm 3 / h), after the re-pressing is finished, pure calcium wire 0.45m / ton of steel is fed. Argon soft blowing flow 1-10Nm 3 / h, soft blowing time 6-10min.

[0049] As can be seen from the above, the embodiment of the present application provides a production method of ship plate steel A36, which optimizes the converter tapping alloying and the input time and input amount of slag washing slag material, adjusts the [C], [Si] and [Mn] in the steel liquid according to the actual smelting L 电弧总平均长度 and LF 进站渣厚 and the maximum F 氩气流量The dosage of lime and fluorite was calculated based on the value relationship, and the dosage of ferrosilicon powder was calculated based on the sampling amount at the argon station. This ensured that the alloying and slag washing time at the converter tapping was appropriate, and that the alloy slag was completely melted. During the LF refining process, the dosage of lime, fluorite, aluminum slag balls, and ferrosilicon powder was more precise, and the slag thickness, arc length, and argon gas were matched, achieving good deoxidation and desulfurization effects. Ultimately, this resulted in higher smelting efficiency and quality of A36 ship plate steel.

[0050] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0051] Example 1

[0052] S1: The converter endpoint C is controlled at 0.07%, O at 700ppm, P at ≤0.015%, and the tapping temperature is controlled at 1630℃.

[0053] S2: Perform alloying and slag washing treatment for converter steel tapping.

[0054] When to add alloying agents: Add 3.3 kg high-carbon ferromanganese per ton of steel, 13.7 kg silicon-manganese per ton of steel, 0.9 kg aluminum-iron per ton of steel, and 0.77 kg vanadium-iron per ton of steel when 1 / 6 of the steel is tapped.

[0055] Timing of adding slag washing materials: Add 4 kg of synthetic slag per ton of steel and 2 kg of lime per ton of steel when the steel is 1 / 2 tapped.

[0056] Alloying is carried out when the steel is 1 / 6 tapped, with 60 Nm of argon gas introduced. 3 / h, immediately reduce to 40Nm after adding the alloy. 3 / h. Replace part of the lime and bauxite with synthetic slag with a low melting point, and carry out the process at 1 / 2 tapping to determine good melting effect.

[0057] When the carbon content (C) of the tapped steel is below 0.07%, manual carbon powder is used for pre-deoxidation and venting (utilizing the CO bubbles generated by the deoxidation reaction of the molten steel to carry away nitrogen), while simultaneously increasing the carbon content to ensure that the C content at the LF station reaches 0.13%. 碳粉 =0.07×[(LF 到站C含量 ×100-Converter 出钢C含量 [(0.13% × 100 - 0.07% × 100)] = 0.42 kg / ton of steel.

[0058] S3: After tapping the steel, reduce the argon gas flow rate to a soft blowing state of 5 Nm. 3 / h, to prevent the molten steel from being exposed.

[0059] Argon station sampling yielded W 氩站C % = 0.13%, W 氩站Si % = 0.18%, and W氩站S % = 0.022%.

[0060] S4: LF refining, comprising the following steps:

[0061] S41: temperature measurement at the inlet, obtaining LF 进站温度 = 1544℃.

[0062] S42: measuring slag thickness with iron pipe at the inlet, obtaining LF 进站渣厚 = 80(mm). When the slag thickness at the inlet is 1mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . From the step S2, it is further obtained that the converter slag washing slag weight G 洗渣 = 4+2 = 6(kg slag / ton of steel). When the slag thickness is 1mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6÷80 = 0.075(kg slag / ton of steel).

[0063] S43: adjusting the dust hood valve to 85%, keeping the slight positive pressure state in the furnace to reduce the absorption of air (mainly N2) by the molten steel during the smelting process. Using the transformer with 11 stages (preheating position) to pass in 38Nm 3 / h argon for 5min to perform slagging, and successively adding lime, fluorite and 1.2kg / ton of steel of aluminum slag balls. Using the transformer with 4 stages as the main heating position to pass in 38Nm 3 / h argon to send electricity, and the average length of the electric arc L1 弧长 is 153mm. X 石灰 = {[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷ LF 进站渣厚 )÷4.5×3.5 = 4.26(kg). Y 萤石 = {[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(6÷ LF 进站渣厚 )÷4.5 = 1.22(kg).

[0064] Among them, Y 萤石 , X 石灰 and aluminum slag balls are added in 5 batches, and Y 萤石 , X 石灰 and aluminum slag balls are mixed and added in each batch. The amount of lime in each batch is X 石灰 / 5 = 0.85(kg / ton of steel), and the amount of fluorite in each batch is Y 萤石 / 5=0.24(kg / ton steel), the amount of aluminum slag ball in each batch is 0.24(kg / ton steel). In this way, the slag surface deoxidizer can be evenly scattered on the slag surface by means of small batch addition, so as to achieve good deoxidation effect.

[0065] S44: after preheating, switch to 4th gear transformer series, and input argon gas 38 Nm 3 / h continue to send power, and perform main heating. When W 氩站Si <0.20% or W 氩站S >0.15% or W 氩站C <0.08%, the total amount of added ferrosilicon powder G 硅铁粉 =G 硅铁粉1 +G 硅铁粉2 +G 硅铁粉3 =(0.20%-W 氩站Si ) / 0.01%*0.21+(W 氩站S -0.015%) / 0.001%*0.07+(0.08%-W 氩站C ) / 0.01%*0.14=(0.20%-0.18%) / 0.01%*0.21+(0.022%-0.015%) / 0.001%*0.07=0.78kg / ton steel.

[0066] S5: when the power is sent to the steel liquid temperature> 1564℃, the power is stopped, and argon gas 60 Nm 3 / h strong stirring for 2 min, sampling 1, and observing the color of sticky slag. The composition 1 is obtained. The sticky slag is preferably thin white slag. When the thin white slag is not reached, 0.14kg / ton steel of ferrosilicon powder is added until the target of the furnace slag is reached. The LF final slag is CaO 58%, SiO2 13%, Al2O3 10%, T Fe 0.6%, MnO 0.4%, S 0.8%, MgO 7%, P2O5 0.07%, basicity R 4.5, and the steel liquid deoxidation and desulfurization effect is best.

[0067] S6: continue main heating, according to the results of composition 1, the [C], [Si], [Mn] in the steel liquid are respectively fine-tuned to the target 0.16%, 0.20%, 1.29%.

[0068] S7: when the steel liquid is heated to the preset requirement 1623℃, the aluminum wire is fed in white slag state 10min before the station, and according to the results of composition 1, the [Als] is adjusted to 0.030%. After feeding the aluminum wire, argon gas 25 Nm 3 / h is input for 9min, so that a small amount of Al2O3 inclusions in the steel liquid can be fully floated.

[0069] S8: sampling 2, temperature measurement. The molten steel is out of the station.

[0070] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 14 min, high vacuum time 11 min, pure degassing time 8 min. Vacuum degree 0.265 KPa, circulation gas flow 72 Nm 3 / h, end of repressing, feeding pure calcium wire 0.45 m / ton of steel. Argon soft blowing flow 7 Nm 3 / h, soft blowing time 6 min.

[0071] Example 2

[0072] S1: The converter end point C is controlled at 0.08%, O at 500 ppm, P at ≤0.015%, and the tapping temperature is controlled at 1622°C.

[0073] S2: Converter tapping alloying and slag washing treatment are carried out.

[0074] Alloying addition timing: 3.2 kg high-carbon ferromanganese / ton of steel, 13.6 kg silicon manganese / ton of steel, 0.8 kg aluminum iron / ton of steel, and 0.76 kg ferrovanadium / ton of steel are added at 1 / 6 of tapping.

[0075] Slag washing material addition timing: 4.1 kg synthetic slag / ton of steel and 2.1 kg lime / ton of steel are added at 1 / 2 of tapping.

[0076] Alloying is carried out at 1 / 6 of tapping, and argon is blown at 60 Nm 3 / h, and immediately after the alloying is completed, it is adjusted to 40 Nm 3 / h. The low-melting synthetic slag is used to replace part of the lime and bauxite, and is carried out at 1 / 2 of tapping to ensure good melting effect.

[0077] When the tapping C is lower than 0.07%, carbon powder is manually added for pre-deoxidation and exhaust (CO bubbles generated by the deoxidation reaction of the molten steel carry nitrogen removal), and at the same time, carbon is increased to ensure that the C at the LF station reaches 0.12%. W 碳粉 = 0.07 x [(LF 到站C含量 x 100 - converter 出钢C含量 x 100)] = 0.07 x [(0.12% x 100 - 0.07% x 100)] = 0.35 kg / ton of steel.

[0078] S3: After the tapping is completed, the argon flow is adjusted to a soft blowing state of 8 Nm 3 / h, so that the molten steel is not exposed.

[0079] Argon station sampling gives W 氩站C %= 0.12%, W 氩站Si %= 0.15%, and W argon station S %= 0.026%.

[0080] S4: LF refining, including the following steps:

[0081] S41: temperature measurement at the entrance, LF 进站温度 = 1535℃.

[0082] S42: slag thickness measurement at the entrance with iron pipe, LF 进站渣厚 = 75(mm). When the slag thickness at the entrance is 1mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . It is further obtained from the step S2 that the converter slag washing slag weight G 洗渣 = 4.1+2.1=6.2(kg slag / ton of steel). When the slag thickness is 1mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6.2÷75=0.083(kg slag / ton of steel).

[0083] S43: adjust the dust hood valve to 85%, keep the slight positive pressure state in the furnace to reduce the air (mainly N2) absorption of the molten steel during the smelting process. Use the transformer with 11 stages (preheating position) to pass in 40Nm 3 / h argon for 4min to make slag, and successively add 1.2kg / ton of steel of lime, fluorite and aluminum slag ball. Use the transformer with 4 stages as the main heating position to pass in 38Nm 3 / h argon to send electricity, and the average length of the electric arc L1 弧长 is 152mm. X 石灰 = {[152+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5×3.5=4.99(kg). Y 萤石 = {[152+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5=1.43(kg).

[0084] Among them, Y 萤石 , X 石灰 and aluminum slag ball are added in 6 batches, and Y 萤石 , X 石灰 and aluminum slag ball are mixed and added in each batch. The amount of lime in each batch is X 石灰 / 6=0.83(kg / ton of steel), and the amount of fluorite in each batch is Y 萤石G = 0.24 (kg / ton of steel), and the amount of aluminum slag ball in each batch is 0.2 (kg / ton of steel). In this way, the slag surface deoxidizer can be uniformly scattered on the slag surface by means of small batch addition, so as to achieve good deoxidation effect.

[0085] S44: After preheating is completed, switch to 4th gear transformer series, and simultaneously input argon gas 40 Nm 3 / h continue to send power, and perform main heating temperature rise. When W 氩站Si < 0.20% or W 氩站S > 0.15% or W 氩站C < 0.08%, the total amount of added ferrosilicon powder G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20%-W 氩站Si %) / 0.01% x 0.21 + (W 氩站S %-0.015%) / 0.001% x 0.07 + (0.08%-W 氩站C %) / 0.01% x 0.14 = (0.20%-0.15%) / 0.01% x 0.21 + (0.026%-0.015%) / 0.001% x 0.07 = 1.75 kg / ton of steel.

[0086] S5: When the power is sent to the steel liquid temperature > 1564℃, the power is stopped, and argon gas 60 Nm is input 3 / h strong stirring for 2 min, sampling 1, and observing the color of sticky slag. The composition 1 is obtained. The sticky slag is preferably thin white slag. When the thin white slag is not reached, 0.14 kg / ton of steel of ferrosilicon powder is added until the target of the furnace slag is reached. The LF final slag is CaO 56%, SiO2 11%, Al2O3 9%, T Fe 0.5%, MnO 0.4%, S 0.7%, MgO 6%, P2O5 0.08%, basicity R 5.1, and the steel liquid deoxidation and desulfurization effect is best.

[0087] S6: Continue main heating, and according to the results of composition 1, respectively adjust [C], [Si], [Mn] in the steel liquid to the target 0.16%, 0.20%, 1.29%.

[0088] S7: When the steel liquid is heated to the preset requirement 1623℃, the aluminum wire is fed in white slag state 10 min before the steel liquid is discharged, and according to the results of composition 1, [Als] is adjusted to 0.033%. After the aluminum wire is fed, argon gas 22 Nm 3 / h is input for 10 min, so that a small amount of Al2O3 inclusions in the steel liquid fully float up.

[0089] S8: Sampling 2, temperature measurement. The molten steel is discharged.

[0090] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 13 min, high vacuum time 10 min, pure degassing time 7 min. Vacuum degree 0.266 KPa, circulation gas flow 70 Nm 3 / h, the end of the repressing, feeding pure calcium wire 0.45 m / ton of steel. Argon soft blowing flow 8 Nm 3 / h, soft blowing time 10 min.

[0091] Example 3

[0092] S1: The converter end point C is controlled at 0.075%, O at 600 ppm, P at ≤0.015%, and the tapping temperature is controlled at 1620°C.

[0093] S2: The converter tapping alloying and slag washing treatment are carried out.

[0094] Alloying addition timing: 3.1 kg high-carbon ferromanganese / ton of steel, 13.5 kg silicon manganese / ton of steel, 0.7 kg aluminum iron / ton of steel, and 0.75 kg vanadium iron / ton of steel are added at 1 / 6 of the tapping.

[0095] Slag washing material addition timing: 3.9 kg synthetic slag / ton of steel and 2.1 kg lime / ton of steel are added at 1 / 2 of the tapping.

[0096] Alloying is carried out at 1 / 6 of the tapping, and argon is blown at 60 Nm 3 / h, and immediately after the alloying is completed, it is reduced to 40 Nm 3 / h. The low-melting synthetic slag is used to replace part of the lime and bauxite, and is carried out at 1 / 2 of the tapping to ensure good melting effect.

[0097] When the tapping C is lower than 0.07%, carbon powder is manually added for pre-deoxidation and exhaust (CO bubbles generated by the deoxidation reaction of the molten steel carry nitrogen removal), and at the same time, the carbon is increased to ensure that the C at the LF station reaches 0.11%. W 碳粉 = 0.07 x [(LF 到站C含量 x 100 - converter 出钢C含量 x 100)] = 0.07 x [(0.11% x 100 - 0.07% x 100)] = 0.28 kg / ton of steel.

[0098] S3: After the tapping is completed, the argon flow is reduced to the soft blowing state at 6 Nm 3 / h, so that the molten steel is not exposed.

[0099] Argon station sampling gives W 氩站C %= 0.11%, W 氩站Si %= 0.17%, and W W氩站S %= 0.024%.

[0100] S4: LF refining, including the following steps:

[0101] S41: temperature measurement at the entrance, LF 进站温度 = 1533℃.

[0102] S42: slag thickness measurement at the entrance with iron pipe, LF 进站渣厚 = 85(mm). When the slag thickness at the entrance is 1mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . From the S2 step, it is further obtained that the converter slag washing slag weight G 洗渣 = 3.9 + 2.1 = 6(kg slag / ton of steel). When the slag thickness is 1mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6÷85 = 0.071(kg slag / ton of steel).

[0103] S43: adjust the dust hood valve to 85%, keep the slight positive pressure state in the furnace to reduce the absorption of air (mainly N2) by the molten steel during the smelting process. Use the transformer with 11 stages (preheating position) to pass in 45Nm 3 / h argon for 3min to perform slagging, and successively add 1.2kg / ton of steel of lime, fluorite and aluminum slag balls. Use the transformer with 4 stages as the main heating position to pass in 38Nm 3 / h argon to send power, and the average arc length L1 弧长 is 153mm. X 石灰 = {[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5×3.5 = 3.83(kg). Y 萤石 = {[153+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5 = 1.09(kg).

[0104] Among them, Y 萤石 , X 石灰 and aluminum slag balls are added in 4 batches, and Y 萤石 , X 石灰 and aluminum slag balls are mixed and added in each batch. The amount of lime in each batch is X 石灰 / 4 = 0.96(kg / ton of steel), and the amount of fluorite in each batch is Y 萤石= 0.27 (kg / ton steel), the amount of aluminum slag ball for each batch is 0.3 (kg / ton steel). In this way, the slag surface deoxidizer can be evenly scattered on the slag surface by means of small batch addition, so as to achieve good deoxidation effect.

[0105] S44: After preheating is completed, switch to 4th gear transformer series, and simultaneously input argon gas 45 Nm 3 / h continue to send power, and perform main heating temperature rise. When W 氩站Si < 0.20% or W 氩站S > 0.15% or W 氩站C < 0.08%, the total amount of added silicon iron powder G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20%-W 氩站Si %) / 0.01% x 0.21 + (W 氩站S %-0.015%) / 0.001% x 0.07 + (0.08%-W 氩站C %) / 0.01% x 0.14 = (0.20%-0.17%) / 0.01% x 0.21 + (0.024%-0.015%) / 0.001% x 0.07 = 1.26 kg / ton steel.

[0106] S5: When the power is sent to the steel liquid temperature > 1564 ℃, the power is stopped, and argon gas 60 Nm 3 / h strong stirring for 2 min, sampling 1, and observing the color of sticky slag. The composition 1 is obtained. The sticky slag is preferably thin white slag. When the thin white slag is not reached, 0.14 kg / ton steel of silicon iron powder is added until the target of the furnace slag is reached. The LF final slag is CaO 58%, SiO2 12%, Al2O3 11%, T Fe 0.4%, MnO 0.3%, S 0.8%, MgO 8%, P2O5 0.09%, basicity R 4.8, and the steel liquid deoxidation and desulfurization effect is best.

[0107] S6: Continue main heating, and according to the results of composition 1, respectively adjust [C], [Si], [Mn] in the steel liquid to the target 0.16%, 0.20%, 1.29%.

[0108] S7: When the steel liquid is heated to the preset requirement 1623 ℃, the aluminum wire is fed in white slag state 10 min before the steel liquid is discharged, and according to the results of composition 1, [Als] is adjusted to 0.031%. After the aluminum wire is fed, argon gas 20 Nm 3 / h is input for 12 min, so that a small amount of Al2O3 inclusions in the steel liquid fully float up.

[0109] S8: Sampling 2, temperature measurement. The molten steel is discharged.

[0110] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 13 min, high vacuum time 10 min, pure degassing time 7 min. Vacuum degree 0.261 KPa, circulation gas flow 68 Nm 3 / h, end of repressing, feeding pure calcium wire 0.45 m / ton of steel. Argon soft blowing flow 7 Nm 3 / h, soft blowing time 9 min.

[0111] Example 4

[0112] S1: The converter end point C is controlled at 0.072%, O at 650 ppm, P at ≤0.015%, and the tapping temperature is controlled at 1618°C.

[0113] S2: The converter tapping alloying and slag washing treatment are carried out.

[0114] Alloying addition timing: 3.15 kg high-carbon ferromanganese / ton of steel, 13.56 kg silicon-manganese / ton of steel, 0.75 kg ferroaluminum / ton of steel, and 0.77 kg ferrovanadium / ton of steel are added at 1 / 6 of tapping.

[0115] Slag washing material addition timing: 4.1 kg synthetic slag / ton of steel and 2 kg lime / ton of steel are added at 1 / 2 of tapping.

[0116] Alloying is carried out at 1 / 6 of tapping, argon is blown at 60 Nm 3 / h, and immediately after the alloying is finished, it is adjusted to 40 Nm 3 / h. The low-melting synthetic slag is used to replace part of the lime and bauxite, and is carried out at 1 / 2 of tapping to ensure good melting effect.

[0117] When the tapping C is lower than 0.07%, carbon powder is manually added for pre-deoxidation and exhaust (CO bubbles generated by the deoxidation reaction of the molten steel carry nitrogen removal), and at the same time, carbon is increased to ensure that the C at the LF station reaches 0.125%. W 碳粉 = 0.07 x [(LF 到站C含量 x 100 - converter 出钢C含量 x 100)] = 0.07 x [(0.125% x 100 - 0.07% x 100)] = 0.39 kg / ton of steel.

[0118] S3: After the tapping is finished, the argon flow is adjusted to a soft blowing state of 7 Nm 3 / h, so that the molten steel is not exposed.

[0119] Argon station sampling gives W 氩站C %= 0.07%, W 氩站Si %= 0.12%, and P W氩站S %= 0.020%.

[0120] S4: LF refining, including the following steps:

[0121] S41: temperature measurement at the entrance, LF 进站温度 = 1530℃.

[0122] S42: slag thickness measurement at the entrance with iron pipe, LF 进站渣厚 = 90(mm). When the slag thickness at the entrance is 1mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . From the step S2, it is further obtained that the converter slag washing slag weight G 洗渣 = 4.1+2 = 6.1(kg slag / ton of steel). When the slag thickness is 1mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6.1÷90 = 0.068(kg slag / ton of steel).

[0123] S43: adjust the dust hood valve to 85%, keep the slight positive pressure in the furnace to reduce the air (mainly N2) absorption of the molten steel during the smelting process. Use the transformer with 11 stages (preheating position) to pass in 42Nm 3 / h argon for 5min to make slag, and successively add 1.2kg / ton of steel of lime, fluorite and aluminum slag ball. Use the transformer with 4 stages as the main heating position to pass in 38Nm 3 / h argon to send electricity, and the average arc length L1 弧长 is 151mm. X 石灰 = {[151+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5×3.5 = 3.3(kg). Y 萤石 = {[151+(F 氩气流量 -38)×0.2]-LF 进站渣厚}×(G 洗渣 ÷LF 进站渣厚 )÷4.5 = 0.93(kg).

[0124] Among them, Y 萤石 , X 石灰 and aluminum slag ball are added in 3 batches, and Y 萤石 , X 石灰 and aluminum slag ball are mixed and added in each batch. The amount of lime in each batch is X 石灰 / 3 = 1.1(kg / ton of steel), and the amount of fluorite in each batch is Y 萤石B = 0.31 (kg / ton of steel), and the amount of aluminum slag balls per batch is 0.4 (kg / ton of steel). In this way, the slag surface deoxidizer can be uniformly scattered on the slag surface by means of small batch addition, so as to achieve good deoxidation effect.

[0125] S44: After preheating is completed, switch to 4th gear transformer series, and simultaneously input argon gas 42 Nm 3 / h continue to send power, and perform main heating temperature rise. When W 氩站Si <0.20% or W 氩站S >0.15% or W 氩站C When <0.08%, the total amount of added ferrosilicon powder G 硅铁粉 =G 硅铁粉1 +G 硅铁粉2 +G 硅铁粉3 =(0.20%-W 氩站Si ) / 0.01% x 0.21+(W 氩站S -0.015%) / 0.001% x 0.07+(0.08%-W 氩站C ) / 0.01% x 0.14=(0.20%-0.12%) / 0.01% x 0.21+(0.020%-0.015%) / 0.001% x 0.07+(0.08%-0.07%) / 0.01% x 0.14=2.17 kg / ton of steel.

[0126] S5: When the power is sent to the steel liquid temperature > 1564℃, stop power, and input argon gas 60 Nm 3 / h strong stirring for 2 min, sampling 1, and observing the color of sticky slag. The composition 1 is obtained. The sticky slag is preferably thin white slag. When the thin white slag is not reached, 0.14 kg / ton of steel of ferrosilicon powder is added until the target of the furnace slag is reached. The LF final slag is CaO 57%, SiO2 13%, Al2O3 12%, T Fe 0.5%, MnO 0.2%, S 0.6%, MgO 9%, P2O5 0.06%, basicity R 4.4, and the steel liquid deoxidation and desulfurization effect is best.

[0127] S6: Continue main heating, and according to the composition 1 result, respectively adjust [C], [Si], and [Mn] in the steel liquid to the target 0.16%, 0.20%, and 1.29%.

[0128] S7: When the steel liquid is heated to the preset requirement 1623℃, the aluminum wire is fed in white slag state 10 min before the steel liquid is discharged, and according to the composition 1 result, [Als] is adjusted to 0.032%. After the aluminum wire is fed, argon gas 26 Nm 3 / h is input for 10 min, so that a small amount of Al2O3 inclusions in the steel liquid are fully floated.

[0129] S8: Sampling 2, temperature measurement. The molten steel leaves the station.

[0130] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 15 min, high vacuum time 12 min, pure degassing time 9 min. Vacuum degree 0.265 KPa, circulation gas flow 66 Nm 3 / h, end of repressurization, feeding of pure calcium wire 0.45 m / ton of steel. Argon soft blowing flow 6 Nm 3 / h, soft blowing time 8 min.

[0131] Comparative Example 1

[0132] S1: The converter end point C is controlled at 0.07%, O at 700 ppm, P at ≤0.015%, and the tapping temperature is controlled at 1630°C.

[0133] S2: Tapping alloying and slag washing treatment are performed.

[0134] Alloying addition timing: 3.3 kg high-carbon ferromanganese / ton of steel, 13.7 kg silicon manganese / ton of steel, 0.9 kg ferroaluminum / ton of steel, and 0.77 kg ferrovanadium / ton of steel are added at 1 / 6 of the tapping.

[0135] Slag washing material addition timing: 4 kg of synthetic slag / ton of steel and 2 kg of lime / ton of steel are added at 1 / 2 of the tapping.

[0136] Alloying is performed at 1 / 6 of the tapping, argon is blown at 60 Nm 3 / h, and the flow is immediately reduced to 40 Nm 3 / h after the alloying is completed. A synthetic slag with a low melting point is used to replace part of the lime and bauxite, and the alloying is performed at 1 / 2 of the tapping to ensure good melting.

[0137] When the tapping C is lower than 0.07%, carbon powder is manually added for pre-deoxidation and exhaust (CO bubbles generated by the deoxidation reaction of the molten steel carry nitrogen), and at the same time, the carbon content is increased to ensure that the C at the LF station is 0.13%. 碳粉 W 到站C含量 = 0.07 x [(LF 出钢C含量 x 100 - converter 3 x 100)] = 0.07 x [(0.13% x 100 - 0.07% x 100)] = 0.42 kg / ton of steel.

[0138] S3: After the tapping is completed, the argon flow is reduced to 5 Nm 3 / h in a soft blowing state to prevent the molten steel from being exposed.

[0139] Sampling at the argon station gives W 氩站C %= 0.13%, W 氩站Si %= 0.18%, and W W氩站S %= 0.022%.

[0140] S4: Perform LF refining, including the following steps:

[0141] S41: Temperature measurement upon entry, resulting in LF. 进站温度 =1544℃.

[0142] S42: The slag thickness is measured using an iron pipe at the station, yielding the LF value. 进站渣厚 =80 (mm). When the slag thickness at the feed station is 1 mm, the slag weight g1 = the weight of the converter slag wash material G. 洗渣 ÷LF 进站渣厚 Further, from step S2, we can deduce the following: the weight G of the converter slag washing material. 洗渣 =4 + 2 = 6 (kg slag / ton of steel). When the slag thickness is 1mm, the weight of the slag, g1 = G 洗渣料用量 ÷LF 进站渣厚 =6 ÷ 80 = 0.075 (kg slag / ton of steel).

[0143] S43: Adjust the dust collector hood regulating valve to 85% to maintain a slightly positive pressure in the furnace draft, reducing the absorption of air (mainly N2) by the molten steel during smelting. Use a transformer with 11 poles (preheating setting) and introduce 38 Nm of argon gas. 3 Slag formation is initiated after 5 minutes of energization, and X is added gradually according to experience. 石灰 3.84 kg / ton of steel, Y 萤石 0.87 kg / ton of steel and 1.2 kg / ton of aluminum slag balls.

[0144] Among them, Y 萤石 X 石灰 Aluminum slag balls were added in 5 batches, and the Y content of each batch was... 萤石 X 石灰 Add it in combination with aluminum slag balls, with the amount of lime per batch being X. 石灰 / 5 = 0.77 (kg / ton of steel), the amount of fluorite in each batch is Y 萤石 / 5 = 0.17 (kg / ton of steel), and the amount of aluminum slag balls in each batch is 0.24 (kg / ton of steel). In this way, the deoxidizer can be evenly distributed on the slag surface by adding it in small batches, so as to achieve a good deoxidation effect.

[0145] S44: Preheating complete. Switch to transformer speed 4 and simultaneously introduce 38 Nm of argon gas. 3 Power continues to be supplied at / h for main heating and temperature increase. X is added empirically from S43. 石灰 3.84 kg / ton of steel, Y 萤石 0.87 kg / ton of steel, with slag thickness less than 4 transformer poles, and argon gas introduced at 38 Nm. 3 The arc length generated by heating at a rate of / h. Unstable electrode submersion arc leads to increased nitrogen absorption by molten steel.

[0146] When W 氩站Si % < 0.20% or W 氩站S % > 0.15% or W 氩站C % < 0.08%, the total amount of added ferrosilicon powder G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20% - W 氩站Si %) / 0.01% x 0.21 + (W 氩站S % - 0.015%) / 0.001% x 0.07 + (0.08% - W 氩站C %) / 0.01% x 0.14 = (0.20% - 0.18%) / 0.01% x 0.21 + (0.022% - 0.015%) / 0.001% x 0.07 = 0.78 kg / ton of steel.

[0147] S5: When the temperature of the molten steel is > 1564°C, power is cut off, argon gas is introduced at 60 Nm 3 / h for 2 minutes of strong stirring, sample 1 is taken, and the color of the adhered slag is observed. The composition 1 is obtained. The adhered slag is preferably thin and white. When thin and white adhered slag is not achieved, 0.14 kg / ton of steel of ferrosilicon powder is added until the target is reached. The final LF slag is CaO 58%, SiO2 13%, Al2O3 10%, T Fe 0.6%, MnO 0.4%, S 0.8%, MgO 7%, P2O5 0.07%, and the basicity R is 4.5. The deoxidation and desulfurization effects of the molten steel are optimal.

[0148] S6: Continue main heating, and according to the results of composition 1, the [C], [Si], and [Mn] in the molten steel are respectively fine-tuned to the targets 0.16%, 0.20%, and 1.29%.

[0149] S7: When the molten steel is warmed to the preset requirement of 1623°C, the aluminum wire is fed in white slag state 10 minutes before the molten steel leaves the station, and according to the results of composition 1, the [Als] is adjusted to 0.030%. After the aluminum wire is fed, argon gas is introduced at 25 Nm 3 / h for 9 minutes to make a small amount of Al2O3 inclusions in the molten steel sufficiently float.

[0150] S8: Sample 2 is taken, and the temperature is measured. The molten steel leaves the station.

[0151] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 14 minutes, high vacuum time 11 minutes, pure degassing time 8 minutes, vacuum degree 0.265 KPa, circulation gas flow 72 Nm 3 / h, re-pressurization is completed, pure calcium wire is fed at 0.45 m / ton of steel. Argon gas soft blowing flow is 7 Nm 3 / h, and soft blowing time is 6 minutes.

[0152] Comparative Example 2

[0153] S1: The converter end point C was controlled at 0.07%, O at 700 ppm, and P at ≤0.015%, and the tapping temperature was controlled at 1630°C.

[0154] S2: Tapping alloying and slag washing were performed.

[0155] Alloying addition timing: 3.3 kg high-carbon ferromanganese per ton of steel, 13.7 kg silicon manganese per ton of steel, 0.9 kg aluminum iron per ton of steel, and 0.77 kg ferrovanadium per ton of steel were added at 1 / 6 of the tapping.

[0156] Slag washing material addition timing: 4 kg of synthetic slag per ton of steel and 2 kg of lime per ton of steel were added at 1 / 2 of the tapping.

[0157] Alloying was performed at 1 / 6 of the tapping, and argon was passed at 60 Nm 3 / h, and immediately after the alloying was completed, the flow was reduced to 40 Nm 3 / h. A synthetic slag with a low melting point was used to replace part of the lime and bauxite, and was added at 1 / 2 of the tapping to ensure good melting.

[0158] When the tapping C was less than 0.07%, carbon powder was manually added for pre-deoxidation and exhaust (CO bubbles generated by the deoxidation reaction of the molten steel carried nitrogen removal), and at the same time, carbon was added to ensure that the C at the LF station reached 0.13%. W 碳粉 = 0.07 × [(LF 到站C含量 × 100 - converter 出钢C含量 × 100)] = 0.07 × [(0.13% × 100 - 0.07% × 100)] = 0.42 kg / ton of steel.

[0159] S3: After the tapping was completed, the argon flow was reduced to 5 Nm 3 / h to achieve soft blowing, so that the molten steel was not exposed.

[0160] Argon station sampling resulted in W 氩站C %= 0.13%, W 氩站Si %= 0.18%, and W W氩站S %= 0.022%.

[0161] S4: LF refining was performed, including the following steps:

[0162] S41: The temperature at the inlet was measured, resulting in LF 进站温度 = 1544°C.

[0163] S42: The slag thickness was measured at the inlet using an iron pipe, resulting in LF 进站渣厚 = 80 (mm). When the slag thickness at the inlet was 1 mm, the slag material weight g1 = the converter slag washing slag material weight G洗渣 ÷LF 进站渣厚 From the further step S2, the weight of the converter slag washing slag material G 洗渣 = 4 + 2 = 6 (kg of slag material per ton of steel). When the slag thickness is 1 mm, the weight of the slag g1= G 洗渣 ÷LF 进站渣厚 = 6 ÷ 80 = 0.075 (kg of slag material per ton of steel).

[0164] S43: Adjust the dust hood valve to 85%, keep the slight positive pressure state of the in-furnace suction force, reduce the air (mainly N2) absorption of the molten steel during the smelting process. Use the transformer with 11 levels (preheating gear) to pass in argon 38 Nm3 / h for 5 min to perform slagging, and successively add lime, fluorite and aluminum slag ball 1.2 kg / ton of steel. Use the transformer with 4 levels as the main heating gear to pass in argon 38 Nm 3 / h, and the average length of the electric arc L1 弧长 is 153 mm. 石灰 = {[153 + (F 氩气流量 - 38) × 0.2] - LF 进站渣厚} × (G 洗渣 ÷LF 进站渣厚 ) ÷ 4.5 × 3.5 = 4.26 (kg). 萤石 = {[153 + (F 氩气流量 - 38) × 0.2] - LF 进站渣厚} × (6 ÷ LF 进站渣厚 ) ÷ 4.5 = 1.22 (kg).

[0165] Among them, Y 萤石 , X 石灰 and aluminum slag ball are added in 5 batches, and Y 萤石 , X 石灰 and aluminum slag ball are mixed and added in each batch. The amount of lime in each batch is X 石灰 / 5 = 0.85 (kg / ton of steel), the amount of fluorite in each batch is Y 萤石 / 5 = 0.24 (kg / ton of steel), and the amount of aluminum slag ball in each batch is 0.24 (kg / ton of steel). In this way, the slag surface deoxidizer can be evenly scattered on the slag surface through small batch addition, so as to achieve good deoxidation effect.

[0166] S44: After preheating, switch to 4 transformer levels, and at the same time pass in argon 38 Nm 3 / h to continue power supply, and perform main heating to raise temperature. Add silicon iron powder 0.15 kg / ton of steel according to experience, and the early deoxidation of the furnace slag is poor, and the silicon loss and aluminum loss of the molten steel are large.

[0167] S5: When the power supply is stopped to the molten steel temperature > 1564℃, the argon 60 Nm3 / h, sample 1, stick slag color observation. The composition 1 was obtained. The stick slag is preferably thin white slag. When the thin white slag is not reached, add 0.14 kg / ton of steel silicon iron powder until the slag reaches the target. The LF final slag is CaO 58%, SiO2 13%, Al2O3 10%, T Fe 0.6%, MnO 0.4%, S 0.8%, MgO 7%, P2O5 0.07%, basicity R 4.5, the steel liquid deoxidation and desulfurization effect is best.

[0168] S6: Continue main heating, according to the results of composition 1, adjust [C], [Si], [Mn] in the steel liquid to the target 0.16%, 0.20%, 1.29% respectively.

[0169] S7: When the steel liquid is heated to the preset requirement 1623℃, the steel liquid is fed with aluminum wire under white slag state 10min before leaving the station, and [Als] is adjusted to 0.030% according to the results of composition 1. After feeding the aluminum wire, 25Nm 3 / h of argon is introduced to keep for 9min, so that a small amount of Al2O3 inclusions in the steel liquid can fully float up.

[0170] S8: Sample 2, temperature measurement. The molten steel leaves the station.

[0171] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 14min, high vacuum time 11min, pure degassing time 8min. Vacuum degree 0.265KPa, circulation gas flow 72Nm 3 / h, after re-pressurization, feed in 0.45m / ton of steel pure calcium wire. The argon soft blowing flow is 7Nm 3 / h, soft blowing time 6min.

[0172] Comparative Example 3

[0173] S1: The converter endpoint C is controlled at 0.07%, O is controlled at 700ppm, P is controlled at ≤0.015%, and the tapping temperature is controlled at 1630℃.

[0174] S2: Perform converter tapping alloying and slag washing treatment.

[0175] Alloying addition timing: add 3.3kg high-carbon ferromanganese / ton of steel, 13.7kg silicon manganese / ton of steel, 0.9kg aluminum iron / ton of steel, and 0.77kg vanadium iron / ton of steel at 1 / 4 of tapping.

[0176] Slag washing material addition timing: add 4kg synthetic slag / ton of steel and 2kg lime / ton of steel at 1 / 2 of tapping.

[0177] Alloying is performed at 1 / 4 of tapping, and 60Nm 3 / h, immediately after alloying, reduce to 40 Nm 3 / h. Alloying is late, alloy melting effect is poor, LF refining process arc flow is unstable, and the molten steel absorbs more nitrogen. Replace part of the lime and bauxite with synthetic slag with low melting point, and perform at 1 / 2 tapping.

[0178] When the tapping C is lower than 0.07%, manually add carbon powder for pre-deoxidization and exhaust (use CO bubbles generated by the deoxidization reaction of the molten steel to carry nitrogen), while increasing the carbon content, to ensure that the C in the LF reaches 0.13%. W 碳粉 = 0.07 × [(LF 到站C含量 × 100 - converter 出钢C含量 × 100)] = 0.07 × [(0.13% × 100 - 0.07% × 100)] = 0.42 kg / ton steel.

[0179] S3: After tapping, reduce the argon flow to 5 Nm 3 / h to make the molten steel not exposed.

[0180] Sampling at the argon station shows that W 氩站C %= 0.13%, W 氩站Si %= 0.18%, and W W氩站S %= 0.022%.

[0181] S4: Perform LF refining, including the following steps:

[0182] S41: Measure the temperature upon entry to obtain LF 进站温度 = 1544°C.

[0183] S42: Measure the slag thickness with an iron pipe upon entry to obtain LF 进站渣厚 = 80 (mm). When the slag thickness is 1 mm, the slag weight g1 = converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . From the further step S2, it is obtained that the converter slag washing slag weight G 洗渣 = 4 + 2 = 6 (kg of slag per ton of steel). When the slag thickness is 1 mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6 ÷ 80 = 0.075 (kg of slag per ton of steel).

[0184] S43: Adjust the dust hood valve to 85% to maintain a slight positive pressure in the furnace, reducing the absorption of air (mainly N2) by the molten steel during the smelting process. Use a transformer with 11 stages (preheating position) to input 38 Nm3 / h of argon for 5 minutes to form slag, and successively add lime, fluorite, and aluminum slag balls at 1.2 kg / ton of steel. Use a transformer with 4 stages as the main heating position to input 38 Nm 3 / h argon power supply, the average length of arc L1 弧长 153 mm. X 石灰 = {[153 + (F 氩气流量 - 38) x 0.2] - LF 进站渣厚} x (G 洗渣 ÷ LF 进站渣厚 ) ÷ 4.5 x 3.5 = 4.26 (kg). Y 萤石 = {[153 + (F 氩气流量 - 38) x 0.2] - LF 进站渣厚} x (6 ÷ LF 进站渣厚 ) ÷ 4.5 = 1.22 (kg).

[0185] Wherein, Y 萤石 , X 石灰 and aluminum slag ball are added in 5 batches, and Y 萤石 , X 石灰 and aluminum slag ball are mixed and added in each batch, the amount of lime in each batch is X 石灰 / 5 = 0.85 (kg / ton of steel), the amount of fluorite in each batch is Y 萤石 / 5 = 0.24 (kg / ton of steel), and the amount of aluminum slag ball in each batch is 0.24 (kg / ton of steel). In this way, the slag surface deoxidizer can be evenly scattered on the slag surface by small batch addition, so as to achieve good deoxidizing effect.

[0186] S44: after preheating, switch to 4th gear transformer series, and input argon 38 Nm 3 / h continue to supply power, and carry out main heating. When W 氩站Si % < 0.20% or W 氩站S % > 0.15% or W 氩站C % < 0.08%, the total amount of silicon iron powder added G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20% - W 氩站Si %) / 0.01% x 0.21 + (W 氩站S % - 0.015%) / 0.001% x 0.07 + (0.08% - W 氩站C %) / 0.01% x 0.14 = (0.20% - 0.18%) / 0.01% x 0.21 + (0.022% - 0.015%) / 0.001% x 0.07 = 0.78 kg / ton of steel.

[0187] S5: when the temperature of the molten steel is greater than 1564℃, stop power supply, and input argon 60 Nm 3 / h, sample 1, stickiness slag color observation. Obtain ingredient 1. Stickiness slag is preferably thin white slag. When thin white slag is not reached, add ferrosilicon powder 0.14 kg / ton of steel until the slag reaches the target. LF final slag is CaO 58%, SiO2 13%, Al2O3 10%, T Fe 0.6%, MnO 0.4%, S 0.8%, MgO 7%, P2O5 0.07%, basicity R 4.5, the steel liquid deoxidation and desulfurization effect is best.

[0188] S6: Continue main heating, according to the results of ingredient 1, adjust [C], [Si], [Mn] in the steel liquid to the target 0.16%, 0.20%, 1.29% respectively.

[0189] S7: When the steel liquid is heated to the preset requirement 1623℃, the steel liquid is fed with aluminum wire under white slag state 10min before leaving the station, and [Als] is adjusted to 0.030% according to the results of ingredient 1. After feeding the aluminum wire, 25Nm 3 / h of argon is introduced to keep for 9min, so that a small amount of Al2O3 inclusions in the steel liquid can fully float up.

[0190] S8: Sample 2, temperature measurement. The molten steel leaves the station.

[0191] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 14min, high vacuum time 11min, pure degassing time 8min. Vacuum degree 0.265KPa, circulation gas flow 72Nm 3 / h, after the re-pressurization is completed, feed in pure calcium wire 0.45m / ton of steel. Argon soft blowing flow 7Nm 3 / h, soft blowing time 6min.

[0192] Comparative Example 4

[0193] S1: The converter endpoint C is controlled at 0.07%, O is controlled at 700ppm, P is controlled at ≤0.015%, and the tapping temperature is controlled at 1630℃.

[0194] S2: Perform converter tapping alloying and slag washing treatment.

[0195] Alloying addition timing: add 3.3kg high-carbon ferromanganese / ton of steel, 13.7kg silicon manganese / ton of steel, 0.9kg aluminum iron / ton of steel, and 0.77kg vanadium iron / ton of steel at 1 / 6 of tapping.

[0196] Slag washing material addition timing: add 4.1kg lime / ton of steel and 2.1kg bauxite / ton of steel at 1 / 2 of tapping.

[0197] Alloying is performed at 1 / 6 of tapping, and argon is introduced at 60Nm 3 / h, immediately after adding alloy, reduce to 40 Nm 3 / h. Large amount of lime is washed by slag, and melting effect is poor. Slag is clotted in LF refining, arc flow is unstable during power transmission, and nitrogen absorption of liquid steel is increased.

[0198] When the C content of liquid steel is lower than 0.07%, carbon powder is manually added for pre-deoxidization and exhaust (CO bubbles generated by deoxidization of liquid steel carry nitrogen), and meanwhile, carbon content is increased to ensure that the C content of liquid steel reaches 0.13% in LF. 碳粉 = 0.07 x [(LF 到站C含量 × 100 - converter 出钢C含量 × 100) = 0.07 x [(0.13% x 100 - 0.07% x 100) = 0.42 kg / ton of steel.

[0199] S3: After tapping, the argon flow is reduced to 5 Nm 3 / h to make the liquid steel not exposed.

[0200] Sampling at the argon station shows that the W 氩站C % = 0.13%, W 氩站Si % = 0.18%, and W W氩站S % = 0.022%.

[0201] S4: LF refining is performed, including the following steps:

[0202] S41: temperature measurement shows that the LF 进站温度 = 1544℃.

[0203] S42: the slag thickness is measured by iron pipe, and the LF 进站渣厚 = 80(mm). When the slag thickness is 1mm, the slag weight g1 = the converter slag washing slag weight G 洗渣 ÷ LF 进站渣厚 . It is further obtained from S2 that the converter slag washing slag weight G 洗渣 = 4+2 = 6(kg slag / ton of steel). When the slag thickness is 1mm, the slag weight g1 = G 洗渣 ÷ LF 进站渣厚 = 6÷80 = 0.075(kg slag / ton of steel).

[0204] S43: the dust hood adjusting valve is adjusted to 85% to keep the suction in the furnace in a slightly positive pressure state to reduce the absorption of air (mainly N2) by the liquid steel during smelting. Slag is formed by using a transformer with 11 stages (preheating position) to pass through 38 Nm 3 / h argon for 5min, and 1.2kg / ton of steel of lime, fluorite and aluminum slag balls are added successively. Power transmission is performed by using a transformer with 4 stages as the main heating position to pass through 38 Nm 弧长 / h argon, and the average arc length L1 石灰= {[153 + (F 氩气流量 - 38) x 0.2] - LF 进站渣厚} x (G 洗渣 ÷ LF 进站渣厚 ) ÷ 4.5 x 3.5 = 4.26 (kg). Y 萤石 = {[153 + (F 氩气流量 - 38) x 0.2] - LF 进站渣厚} x (6 ÷ LF 进站渣厚 ) ÷ 4.5 = 1.22 (kg).

[0205] Wherein, Y 萤石 , X 石灰 and aluminum slag ball are added in 5 batches, and Y 萤石 , X 石灰 and aluminum slag ball are mixed and added in each batch, the amount of lime in each batch is X 石灰 / 5 = 0.85 (kg / ton of steel), the amount of fluorite in each batch is Y 萤石 / 5 = 0.24 (kg / ton of steel), and the amount of aluminum slag ball in each batch is 0.24 (kg / ton of steel). In this way, the slag surface deoxidizer can be evenly scattered on the slag surface by means of small batch addition, so as to achieve good deoxidizing effect.

[0206] S44: after preheating, switch to 4th transformer series, and at the same time, input argon gas 38 Nm 3 / h to continue power supply, and carry out main heating temperature rise. When W 氩站Si % < 0.20% or W 氩站S % > 0.15% or W 氩站C % < 0.08%, the total amount of added silicon iron powder G 硅铁粉 = G 硅铁粉1 + G 硅铁粉2 + G 硅铁粉3 = (0.20% - W 氩站Si %) / 0.01% x 0.21 + (W 氩站S % - 0.015%) / 0.001% x 0.07 + (0.08% - W 氩站C %) / 0.01% x 0.14 = (0.20% - 0.18%) / 0.01% x 0.21 + (0.022% - 0.015%) / 0.001% x 0.07 = 0.78 kg / ton of steel.

[0207] S5: when the temperature of the molten steel is greater than 1564℃, stop power supply, and input argon gas 60 Nm 3strong stirring for 2 min, sample 1, stick slag color observation. The composition 1 is obtained. The stick slag is preferably thin white slag. When the thin white slag is not reached, silicon iron powder 0.14 kg / ton of steel is added until the target is reached. The LF final slag is CaO 58%, SiO2 13%, Al2O3 10%, T Fe 0.6%, MnO 0.4%, S 0.8%, MgO 7%, P2O5 0.07%, basicity R 4.5, and the steel liquid deoxidation and desulfurization effect is best.

[0208] S6: Continue main heating, according to the composition 1 result, the [C], [Si], [Mn] in the steel liquid are respectively fine tuned to the target 0.16%, 0.20%, 1.29%.

[0209] S7: When the steel liquid is heated to the preset requirement 1623℃, the steel liquid is fed with aluminum wire under white slag state 10 min before the station, and [Als] is adjusted to 0.030% according to the composition 1 result. After the aluminum wire is fed, argon gas 25 Nm 3 / h is introduced to keep for 9 min, so that a small amount of Al2O3 inclusions in the steel liquid is fully floated.

[0210] S8: Sample 2, temperature measurement. The molten steel leaves the station.

[0211] S9: Subsequent RH vacuum treatment. The treatment conditions are set as follows: vacuum treatment time 14 min, high vacuum time 11 min, pure degassing time 8 min. Vacuum degree 0.265 KPa, circulation gas flow 72 Nm 3 / h, after the re-pressurization, pure calcium wire 0.45 m / ton of steel is fed. Argon soft blowing flow 7 Nm 3 / h, soft blowing time 6 min.

[0212] The above is only a preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a ship plate steel A36, characterized in that, The method comprises the following steps: Converter tapping is used to deoxidize and alloy the molten steel and perform slag washing treatment; After the steel is discharged, the sample is taken at the argon station, and W 氩站C , W 氩站Si , and W氩站S are measured. LF refining is performed: the steel melt enters the station where the LF 进站温度 and the LF 进站渣厚 ; The first power is used to preheat and raise temperature, argon is introduced, lime and fluorite are added as slag materials, and aluminum slag ball is added as a slag surface deoxidizer for slagging and deoxidizing. The addition amounts of lime and fluorite are calculated according to actual smelting L 电弧总平均长度 The LF 进站渣厚 The maximum F 氩气流量 value relationship is calculated before smelting ends. After preheating is completed, main heating is performed by using second power, argon is continuously introduced, and ferrosilicon powder is added for subsequent slag surface deoxidization, wherein the addition amount of the ferrosilicon powder is calculated according to the sampling amount of the argon station; After slagging, power is cut off, argon is stirred, sampling 1 is performed, analysis results are obtained, the composition content of the molten steel is adjusted according to the target composition requirement, then the molten steel is heated and fed with aluminum wire, argon is blown from the bottom to stir, sampling 2 is performed, analysis results are obtained, and the composition of the molten steel is adjusted until the composition meets the target composition, and then the molten steel is tapped; The molten steel is subjected to RH vacuum treatment to obtain ship plate steel A36; In the method, the converter tapping to deoxidize and alloy the molten steel and perform slag washing treatment comprises the following control indexes: In the LF refining process, Y 萤石 , X 石灰 , and aluminum slag ball 1.2 kg / ton of steel are added, wherein: the fluorite addition amount Y 萤石 = {[main heating gear L 电极弧长，mm + (maximum F 氩气流量，Nm3 / h - main heating gear 氩气流量，Nm3 / h ) × 0.2] - LF 进站渣厚，mm} × (converter 出钢渣洗料用量，kg / 吨钢 ÷ LF 进站渣厚，mm ) ÷ 4.5, unit: kg, the lime addition amount X 石灰 = 3.5 × Y 萤石 , unit: kg; In the LF refining process, according to the argon station sampling amount, when W 氩站 %≥0.20%, without adding ferrosilicon powder, every heating for 5 minutes, add 0.08 kg / ton steel of aluminum slag ball for diffusion deoxidation, G 铝渣球加入量 =0.08×(T 加热 ÷5), unit: kg / ton steel; when W 氩站Si %<0.20% or W 氩站S %>0.15% or W 氩站C %<0.08%, the total amount of added ferrosilicon powder G 硅铁 powder=(0.20%-W 氩站Si %) / 0.01%×0.21+(W 氩站S %-0.015%) / 0.001%×0.07+(0.08%-W 氩站C %) / 0.01%×0.14, unit: kg / ton steel.

2. The production method according to claim 1, characterized by, The converter end point C is controlled to be 0.07%-0.08%, O is controlled to be 500-700ppm, P is controlled to be ≤0.015%, and the tapping temperature is controlled to be 1610±20℃. At 1 / 6 of the converter tapping, argon is blown at 55-60 Nm 3 / h, 3.1-3.3 kg high-carbon ferromanganese per ton of steel, 13.5-13.7 kg ferrosilicon per ton of steel, 0.7-0.9 kg ferroaluminum per ton of steel, and 0.75-0.77 kg ferrovanadium per ton of steel are added, and immediately after the addition of the alloy, the blowing is reduced to 38-42 Nm 3 / h, at 1 / 2 of the converter tapping, 3.9-4.1 kg synthetic slag per ton of steel and 1.9-2.1 kg lime per ton of steel are added. When the tapping C is less than 0.07%, the carbon powder is manually added for pre-deoxidation and exhaust, and at the same time, the carbon is increased to ensure that the LF reaches 0.12%-0.14% at the station C, and the amount of carbon powder added W 碳粉 =0.07×(LF 到站C含量 - converter 出钢C含量 ) ×100, unit: kg / ton of steel; After tapping, the argon flow rate is adjusted to 5-10 Nm3 / min for soft blowing 3 / h so that the liquid steel is not exposed.

3. The production method according to claim 1, characterized by, Y 萤石 X 石灰 Aluminum slag balls are added in batches, with each batch containing Y... 萤石 X 石灰 Add it in combination with aluminum slag balls.

4. The production method according to claim 1, characterized by, The first power is 5000-8000 kW, the first power feeding time is 180-300 s, and the argon flow is 35-40 Nm 3 / h, the second power is 12000-15000 kW, the second power feeding time is 300-600 s, and the argon flow is 35-40 Nm 3 / h.

5. The production method according to claim 1, characterized by, Sample 1, analysis results, adjust the molten steel composition content according to the target component requirements, including: after the calculated amount of ferrosilicon powder is added, continue to send electricity until the molten steel temperature is greater than 1564℃, stop the power supply, and blow in argon gas at 60Nm 3 / h strong stirring for 2 minutes, observe the color of the sticky slag, and when the white slag standard is reached, directly sample 1; when the white slag standard is not reached, supplement 0.07-0.21 kg / ton of steel of ferrosilicon powder for deoxidization, continue strong stirring until the top slag turns white and sample 1, and after the slag composition reaches the target, continue to supply power for main heating; according to the component results of sample 1, respectively adjust the [C], [Si], [Mn] in the molten steel to the target 0.16%, 0.20%, 1.29%.

6. The production method according to claim 1, characterized by, Sampling 2, analyzing results, until the molten steel composition meets the target composition, and then tapping the molten steel, including: after adjusting the molten steel composition according to the target composition requirements, heating the molten steel to a preset requirement of 1623±5℃, feeding the molten steel with aluminum wire in a white slag state 10 minutes before the outlet, adjusting [Als] to 0.030%-0.033% according to the composition results of sampling 1, feeding the aluminum wire, and blowing argon gas at 20-25Nm 3 / h for 10 minutes to make a small amount of Al2O3 inclusions in the molten steel sufficiently float, sampling 2, measuring temperature, and tapping the molten steel.

7. The production method according to claim 1, characterized by, The conditions for RH vacuum treatment of the molten steel are set as follows: vacuum treatment time ≥ 13 min, high vacuum time ≥ 10 min, pure degassing time ≥ 7 min, vacuum degree ≤ 0.266 KPa, circulation gas flow 40-72 Nm 3 / h, end of repressing, feeding pure calcium wire 0.45 m / ton of steel, adjusting argon flow to 1-10 Nm 3 / h, soft blowing time 6-10 min.