Deep purification smelting method for high-purity steel

Abstract

The invention relates to a deep purification smelting method for high-purity steel, and relates to the technical field of high-purity steel smelting. The steel comprises the following chemical components in percentage by weight: 0.17%-0.18% of C, 0.65%-0.7% of Mn, 0.006%-0.01% of S, 0.006%-0.01% of P, 0.18%-0.23% of Si, 1.6%-1.65% of Cr, 1.5%-1.55% of Ni, 0.28%-0.29% of Mo, 0.1%-0.15% of Cu, 0.02%-0.025% of Al, 1.0 ppm-1.2 ppm of H, 10 ppm-15 ppm of O and 60 ppm-70 ppm of N. The method comprises the following operation steps: smelting crude molten steel in an electric arc furnace, performing vacuum refining, performing double-vacuum degassing, and performing gas protection die casting. The ferrocenyl intercalated talcum powder is prepared from talcum powder, gamma-mercaptopropyltrimethoxysilane, water, sodium p-styrenesulfonate, N-ferrocenyl-maleimide and sodium hydroxide, and the ferrocenyl intercalated talcum powder is prepared from the talcum powder, gamma-mercaptopropyltrimethoxysilane, water, sodium p-styrenesulfonate, N-ferrocenyl-maleimide and sodium hydroxide.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity steel smelting, in particular to a deep purification and smelting method of high-purity steel. Background Art

[0002] Clean steel generally refers to steel with very little non-metallic inclusions, gas elements (hydrogen, oxygen, nitrogen) and residual harmful elements (sulfur, phosphorus, copper, arsenic, antimony, tin). The number of non-metallic inclusions, gas content or residual harmful element content level can represent the purity of steel.

[0003] Chinese patent CN118957390A: discloses a smelting process of high-alloy ultra-pure steel, which relates to the field of metallurgical technology, including: electric arc furnace smelting: using a combination of high-quality scrap steel and molten iron for smelting; ladle refining furnace smelting: using aluminum for deoxidation, adding aluminum wire and refining lime for refining; vacuum refining furnace smelting: adding calcium wire for vacuum refining.

[0004] Chinese patent CN102146502A: Provides a RH pure steel smelting and deep decarburization process, which is characterized in that a through hole is opened on the lower wall of the RH ascending / descending tube, which is connected to an external gas source or powder feeding equipment through a nozzle, and CO2 gas is sprayed into the molten steel through the nozzle during RH refining. Alternatively, one or more powders of CaCO3, BaCO3, MgCO3, NaCO3, FeO, Fe2O3 or MnO are sprayed into the molten steel using nitrogen, argon, carbon dioxide or carbon monoxide gas as a carrier.

[0005] Chinese patent CN101643882A: Pure steel smelting method for S-resistant steel oil well pipe, relates to a smelting and preparation technology for oil well pipe blanks used in corrosive oil and gas field environments. Applicable chemical composition is (weight percentage) C0.20-0.35%, Si≤1.00%, Mn≤0.60%, P≤0.015%, S≤0.010%, Cr≤1.50%, Mo0.15-1.0%, Als0.01-0.06%, Ti≤0.09%, Nb≤0.05%, N≤0.0030%, O≤0.0030%, H≤0.0002%, and the rest is Fe and unavoidable impurities. The present invention adopts the following production process route for the pure steel with the above composition: batching selection → electric arc furnace smelting → LF furnace refining → VD furnace refining → arc continuous casting, hydraulic control and full protection casting.

[0006] The pure steel prepared by the above patents and prior art has problems such as complex process and high cost, and the mechanical properties need to be further improved. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a deep purification and smelting method for high-purity steel. The chemical components of the high-purity steel contain, by weight percentage, C: 0.17-0.18%, Mn: 0.65-0.7%, S: 0.006-0.01%, P: 0.006-0.01%, Si: 0.18-0.23%, Cr: 1.6-1.65%, Ni: 1.5-1.55%, Mo: 0.28-0.29%, Cu: 0.1-0.15%, Al: 0.02-0.025%, H: 1.0-1.2ppm, O: 10-15ppm, N: 60-70ppm, and the operating steps include: smelting crude molten steel in an electric arc furnace, vacuum refining, double vacuum degassing, and gas shielded mold casting.

[0008] The electric arc furnace smelts crude molten steel for 10 minutes before tapping, and oxygen is blown for decarburization, and the molten steel boils to remove gas inclusions; argon is blown for 5-8 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

[0009] The vacuum refining temperature is 1550-1600°C, the refining time is 30-60min, and the argon pressure is controlled at 0.15-0.35MPa throughout the process.

[0010] The first vacuum holding time of the double vacuum degassing is 12-17 minutes, the second vacuum holding time is 10-15 minutes, and the vacuum degree is 67Pa; the argon pressure during the vacuum holding period is 0.1-0.3MPa; after the second vacuum breaking, argon soft blowing is performed and the ladle is left to stand for 10 minutes before ladle pouring.

[0011] The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

[0012] The gas protection mold casting adopts argon protection pouring.

[0013] The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

[0014] The production method of the pure calcium cored wire comprises the following steps:

[0015] S1: Preparation and filling of passivation liquid: Methyl silicone oil and ferrocenyl intercalated talc are weighed according to weight percentages of 83-94% and 6-17% respectively and stirred for 20-30 minutes to prepare passivation liquid, and then the passivation liquid is loaded into the passivation processor and the passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor;

[0016] S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into a 6-8mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%;

[0017] S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

[0018] The preparation method of the ferrocenyl intercalated talc is as follows:

[0019] T1: Prepare a solution: Disperse 100-120 parts of talc and 0.3-0.8 parts of γ-mercaptopropyltrimethoxysilane in 1000-1200 parts of water by weight, stir and react at 80-90°C for 2-5 hours to prepare a suspension;

[0020] T2: Add 10-16 parts of sodium p-styrene sulfonate, 0.5-2.6 parts of N-ferrocenyl-maleimide, and 3-6 parts of sodium hydroxide to 100-200 parts of water, and gradually add to the T1 talc suspension, and stir and react at 60-70°C for 60-100 hours;

[0021] T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

[0022] When the pure calcium cored wire is treated with calcium, a 20-40 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 20-50 cm, the wire feeding speed is 1.5-3.5 m / s, and the wire feeding amount is 1.3-2.0 m / ton of steel.

[0023] Reaction mechanism

[0024] Talc is modified with γ-mercaptopropyltrimethoxysilane to obtain mercapto talc; mercapto talc is subjected to mercapto-ene addition reaction with sodium p-styrene sulfonate and N-ferrocenyl-maleimide to obtain ferrocenyl intercalated talc; and the talc is used to prepare pure calcium cored wire to obtain pure calcium cored wire with ferrocenyl intercalation.

[0025] Technical Effects

[0026] The microporous structure of bentonite after ferrocene intercalation is significantly improved, which is mainly reflected in the following aspects:

[0027] 1. Increased interlayer spacing: Through intercalation modification, organic or inorganic molecules such as ferrocene are inserted into the interlayers of bentonite, so that the originally tightly packed silicate sheets are stretched open, thereby increasing the interlayer spacing; this increase in interlayer spacing not only changes the physical properties of bentonite, but also provides it with more microporous space.

[0028] 2. Increase in micropore volume: As the interlayer spacing increases, the micropore volume inside the bentonite also increases; these micropores provide more active sites for adsorption and catalytic reactions, improving the adsorption capacity and catalytic performance of bentonite.

[0029] 3. Increased specific surface area: After intercalation modification, the specific surface area of ​​bentonite increases significantly; this is because the introduction of the intercalation agent breaks the tight stacking of the original sheets, forming more pores and channels, which increases the specific surface area. The increase in specific surface area means that more surface atoms are exposed, which is conducive to adsorption and catalytic reactions.

[0030] 4. Enhanced structural stability: The intercalated bentonite not only has a larger microporous structure and a higher specific surface area, but also exhibits better structural stability; this is because there is a strong interaction force between the intercalant and the bentonite, which can stabilize the intercalated structure and prevent it from collapsing or deforming.

[0031] In summary, the micropore structure of bentonite after ferrocene intercalation has been significantly improved, including increased interlayer spacing, increased micropore volume, increased specific surface area, increased porosity and enhanced structural stability. These changes make the intercalated bentonite have a wider application prospect in the fields of adsorption and catalysis. DETAILED DESCRIPTION

[0032] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description in combination with embodiments and comparative examples:

[0033] Determination of mechanical properties of ultra-pure steel: Test in accordance with GB / T288.1-2021.

[0034] Ca recovery rate: The calcium recovery rate is used to calculate the proportion of calcium absorbed by the molten steel. The calculation formula is: Where: R is the calcium recovery rate; wS,I and wS,F are the mass fractions of calcium in the initial and final state molten steel samples, respectively; wCa / S is the ratio of the mass of calcium added to the molten steel during the two sampling periods to the mass of the molten steel in the ladle.

[0035] Number of continuous casting furnaces / furnaces / tundishes: When a new tundish is used for casting, the start time of the first furnace of molten steel casting will be recorded. After that, each furnace of molten steel casting will be recorded. Until the tundish needs to be replaced or the casting is finished, the end time of the last furnace of molten steel casting will be recorded. By counting the number of furnaces cast in this time period, the value of the number of continuous casting furnaces / furnaces / tundishes can be obtained.

[0036] Example 1

[0037] A method for deep purification and smelting of high-purity steel, wherein the chemical components thereof contain, by weight percentage, the following: C: 0.17%, Mn: 0.65%, S: 0.006%, P: 0.006%, Si: 0.18%, Cr: 1.6%, Ni: 1.5%, Mo: 0.28%, Cu: 0.1%, Al: 0.02%, H: 1.0ppm, O: 10ppm, N: 60ppm, and the operating steps thereof include: smelting crude molten steel in an electric arc furnace, vacuum refining, double vacuum degassing, and gas-protected mold casting.

[0038] The electric arc furnace smelts crude molten steel and performs oxygen decarburization 10 minutes before tapping, and the molten steel boils to remove gas inclusions; argon is blown for 5 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

[0039] The refining temperature of the vacuum refining is 1550° C., and the refining time is 30 minutes; the argon pressure is controlled at 0.15 MPa throughout the process.

[0040] The double vacuum degassing has a primary vacuum holding time of 12 minutes, a secondary vacuum holding time of 10 minutes, and a vacuum degree of 67 Pa; the argon pressure during the vacuum holding period is 0.1 MPa; after the secondary vacuum breaking, argon soft blowing is performed and the ladle is allowed to stand for 10 minutes before ladle pouring.

[0041] The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

[0042] The gas protection mold casting adopts argon protection pouring.

[0043] The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

[0044] The production method of the pure calcium cored wire comprises the following steps:

[0045] S1: Preparation and filling of passivation liquid: Methyl silicone oil and talc powder intercalated with ferrocenyl are weighed according to weight percentages of 94% and 6% respectively and stirred for 20 minutes to prepare passivation liquid, and then the passivation liquid is loaded into the passivation processor and the passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor;

[0046] S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into 6mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%;

[0047] S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

[0048] The preparation method of the ferrocenyl intercalated talc is as follows:

[0049] T1: Prepare a solution: disperse 100 g of talc and 0.3 g of γ-mercaptopropyltrimethoxysilane in 1000 g of water, stir and react at 80°C for 2 hours to prepare a suspension;

[0050] T2: 10 g of sodium p-styrene sulfonate, 0.5 g of N-ferrocenyl-maleimide and 3 g of sodium hydroxide were added to 100 g of water, and then gradually added to the T1 talc suspension, and stirred at 60°C for 60 hours;

[0051] T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

[0052] When the pure calcium cored wire is treated with calcium, a 20 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 20 cm, the wire feeding speed is 1.5 m / s, and the wire feeding amount is 1.3 m / ton of steel.

[0053] Example 2

[0054] A method for deep purification and smelting of high-purity steel, wherein the chemical components thereof contain, by weight percentage, the following: C: 0.17%, Mn: 0.66%, S: 0.007%, P: 0.007%, Si: 0.19%, Cr: 1.61%, Ni: 1.51%, Mo: 0.28%, Cu: 0.11%, Al: 0.021%, H: 1.1ppm, O: 12ppm, N: 64ppm, and the operating steps thereof include: smelting crude molten steel in an electric arc furnace, vacuum refining, double vacuum degassing, and gas-protected mold casting.

[0055] The electric arc furnace smelts crude molten steel and performs oxygen decarburization 10 minutes before tapping, and the molten steel boils to remove gas inclusions; argon is blown for 6 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

[0056] The refining temperature of the vacuum refining is 1560° C., the refining time is 40 min, and the argon pressure is controlled at 0.2 MPa throughout the process.

[0057] The first vacuum holding time of the double vacuum degassing is 13 minutes, the second vacuum holding time is 12 minutes, and the vacuum degree is 67Pa; the argon pressure during the vacuum holding period is 0.2MPa; after the second vacuum breaking, argon soft blowing is performed and the ladle is left to stand for 10 minutes before ladle pouring.

[0058] The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

[0059] The gas protection mold casting adopts argon protection pouring.

[0060] The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

[0061] The production method of the pure calcium cored wire comprises the following steps:

[0062] S1: Preparation and filling of passivation liquid: Methyl silicone oil and talc powder intercalated with ferrocenyl are weighed according to weight percentages of 90% and 10% respectively and stirred for 25 minutes to prepare passivation liquid, and then the passivation liquid is loaded into the passivation processor and the passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor;

[0063] S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into 7mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%;

[0064] S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

[0065] The preparation method of the ferrocenyl intercalated talc is as follows:

[0066] T1: Prepare a solution: Disperse 105 g of talc and 0.5 g of γ-mercaptopropyltrimethoxysilane in 1050 g of water, stir and react at 85 °C for 3 hours to prepare a suspension;

[0067] T2: 12 g of sodium p-styrene sulfonate, 1 g of N-ferrocenyl-maleimide and 4 g of sodium hydroxide were added to 140 g of water, and then gradually added to the T1 talc suspension, and stirred at 65°C for 70 hours;

[0068] T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

[0069] When the pure calcium cored wire is treated with calcium, a 25 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 30 cm, the wire feeding speed is 2 m / s, and the wire feeding amount is 1.5 m / ton of steel.

[0070] Example 3

[0071] A deep purification and smelting method for high-purity steel, wherein the chemical components thereof contain, by weight percentage, the following: C: 0.18%, Mn: 0.68%, S: 0.009%, P: 0.009%, Si: 0.21%, Cr: 1.64%, Ni: 1.54%, Mo: 0.29%, Cu: 0.14%, Al: 0.024%, H: 1.1ppm, O: 14ppm, N: 68ppm, and the operating steps thereof include: smelting crude molten steel in an electric arc furnace, vacuum refining, double vacuum degassing, and gas-protected mold casting.

[0072] The electric arc furnace smelts crude molten steel and performs oxygen decarburization 10 minutes before tapping, and the molten steel boils to remove gas inclusions; argon is blown for 7 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

[0073] The refining temperature of the vacuum refining is 1580° C., and the refining time is 50 min. The argon pressure is controlled at 0.3 MPa throughout the whole process.

[0074] The first vacuum holding time of the double vacuum degassing is 16 minutes, the second vacuum holding time is 14 minutes, and the vacuum degree is 67Pa; the argon pressure during the vacuum holding period is 0.2MPa; after the second vacuum breaking, argon soft blowing is performed and the ladle is left to stand for 10 minutes before ladle pouring.

[0075] The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

[0076] The gas protection mold casting adopts argon protection pouring.

[0077] The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

[0078] The production method of the pure calcium cored wire comprises the following steps:

[0079] S1: Preparation and filling of passivation liquid: Methyl silicone oil and ferrocenyl intercalated talc are weighed in weight percentages of 85% and 15% respectively and stirred for 25 minutes to prepare a passivation liquid, and then the passivation liquid is loaded into a passivation processor and a passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor;

[0080] S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into 7mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%;

[0081] S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

[0082] The preparation method of the ferrocenyl intercalated talc is as follows:

[0083] T1: Prepare a solution: Disperse 115 g of talc and 0.6 g of γ-mercaptopropyltrimethoxysilane in 1150 g of water, stir and react at 85 °C for 4 hours to prepare a suspension;

[0084] T2: 14 g of sodium p-styrene sulfonate, 2 g of N-ferrocenyl-maleimide and 5 g of sodium hydroxide were added to 180 g of water, and then gradually added to the T1 talc suspension, and stirred at 65°C for 90 hours;

[0085] T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

[0086] When the pure calcium cored wire is treated with calcium, a 35 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 40 cm, the wire feeding speed is 3 m / s, and the wire feeding amount is 1.8 m / ton of steel.

[0087] Example 4

[0088] A method for deep purification and smelting of high-purity steel, wherein the chemical components thereof contain, by weight percentage, the following: C: 0.18%, Mn: 0.7%, S: 0.01%, P: 0.01%, Si: 0.23%, Cr: 1.65%, Ni: 1.55%, Mo: 0.29%, Cu: 0.15%, Al: 0.025%, H: 1.2ppm, O: 15ppm, N: 70ppm, and the operating steps thereof include: smelting crude molten steel in an electric arc furnace, vacuum refining, double vacuum degassing, and gas-protected mold casting.

[0089] The electric arc furnace smelts crude molten steel for 10 minutes before tapping, and oxygen is blown for decarburization, and the molten steel boils to remove gas inclusions; argon is blown for 8 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

[0090] The vacuum refining has a refining temperature of 1600° C. and a refining time of 60 min. The argon pressure is controlled at 0.35 MPa during the whole process.

[0091] The first vacuum holding time of the double vacuum degassing is 17 minutes, the second vacuum holding time is 15 minutes, and the vacuum degree is 67Pa; the argon pressure during the vacuum holding period is 0.3MPa; after the second vacuum breaking, argon soft blowing is performed and the ladle is left to stand for 10 minutes before ladle pouring.

[0092] The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

[0093] The gas protection mold casting adopts argon protection pouring.

[0094] The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

[0095] The production method of the pure calcium cored wire comprises the following steps:

[0096] S1: Preparation and filling of passivation liquid: Methyl silicone oil and ferrocenyl intercalated talc are weighed according to weight percentages of 83% and 17% respectively and stirred for 30 minutes to prepare a passivation liquid, and then the passivation liquid is loaded into a passivation processor and a passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor;

[0097] S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into 8mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%;

[0098] S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

[0099] The preparation method of the ferrocenyl intercalated talc is as follows:

[0100] T1: Prepare a solution: Disperse 120 g of talc and 0.8 g of γ-mercaptopropyltrimethoxysilane in 1200 g of water, stir and react at 90°C for 5 hours to prepare a suspension;

[0101] T2: 16 g of sodium p-styrene sulfonate, 2.6 g of N-ferrocenyl-maleimide and 6 g of sodium hydroxide were added to 200 g of water, and then gradually added to the T1 talc suspension, and stirred at 70°C for 100 hours;

[0102] T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

[0103] When the pure calcium cored wire is treated with calcium, a 40 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 50 cm, the wire feeding speed is 3.5 m / s, and the wire feeding amount is 2.0 m / ton of steel.

[0104] Comparative Example 1

[0105] The ferrocenyl intercalated talc was not added, and the other steps were the same as in Example 1.

[0106] Comparative Example 2

[0107] The other steps were the same as in Example 1 except that γ-mercaptopropyltrimethoxysilane was not added.

[0108] Comparative Example 3

[0109] The other steps were the same as in Example 1 except that N-ferrocenyl-maleimide was not added.

[0110] The test results are shown in Table 1:

[0111] Table 1

[0112]

[0113] Through the data analysis of the above embodiments and comparative examples, the pure calcium cored wire prepared by the present invention significantly improves the yield of Ca element and the number of continuous casting furnaces; the high-purity steel prepared by the present invention has a tensile strength of 471 MPa and an elongation of 35%, and has good mechanical properties.

[0114] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for deep purification and smelting of high-purity steel, wherein the chemical components thereof contain, by weight percentage, C: 0.17-0.18%, Mn: 0.65-0.7%, S: 0.006-0.01%, P: 0.006-0.01%, Si: 0.18-0.23%, Cr: 1.6-1.65%, Ni: 1.5-1.55%, Mo: 0.28-0.29%, Cu: 0.1-0.15%, Al: 0.02-0.025%, H: 1.0-1.2ppm, O: 10-15ppm, N: 60-70ppm, and the operation steps thereof include: Electric arc furnace smelting of crude steel, vacuum refining, double vacuum degassing, gas shielded die casting; The vacuum refining is performed by adding pure calcium cored wire for vacuum refining; The production of the pure calcium cored wire is performed by adding talc powder intercalated with ferrocene; The raw materials for preparing the ferrocenyl intercalated talc powder include talc powder, gamma-mercaptopropyltrimethoxysilane, sodium p-styrene sulfonate and N-ferrocenyl-maleimide.

2. The deep purification and smelting method of high-purity steel according to claim 1, characterized in that: The electric arc furnace smelts crude molten steel for 10 minutes before tapping, and oxygen is blown for decarburization, and the molten steel boils to remove gas inclusions; argon is blown for 5-8 minutes before tapping, and argon is blown from the bottom of the ladle throughout the tapping process.

3. The deep purification and smelting method of high-purity steel according to claim 1, characterized in that: The vacuum refining has a refining temperature of 1550-1600°C and a refining time of 30-60 minutes; the argon pressure is controlled at 0.15-0.35 MPa throughout the process.

4. The deep purification and smelting method of high-purity steel according to claim 1 is characterized in that: The first vacuum holding time of the double vacuum degassing is 12-17 minutes, the second vacuum holding time is 10-15 minutes, and the vacuum degree is 67Pa; the argon pressure during the vacuum holding period is 0.1-0.3MPa; after the second vacuum breaking, argon soft blowing is performed and the ladle is left to stand for 10 minutes before ladle pouring.

5. The deep purification and smelting method of high purity steel according to claim 1, characterized in that: The double vacuum degassing is completed until the entire process is covered by molten steel and slag liquid before pouring.

6. The deep purification and smelting method of high purity steel according to claim 1, characterized in that: The gas protection mold casting adopts argon protection pouring.

7. The deep purification and smelting method of high purity steel according to claim 1, characterized in that: The vacuum refining is performed by adding pure calcium cored wire for vacuum refining, using Ca to denature inclusions to generate calcium aluminate inclusions, and by blowing argon and stirring, the inclusions float to the top slag for adsorption and removal; at the same time, the extreme vacuum and carbon-oxygen reduction reaction are used to further remove oxide inclusions.

8. The deep purification and smelting method of high purity steel according to claim 7, characterized in that: The production method of the pure calcium cored wire comprises the following steps: S1: Preparation and filling of passivation liquid: Methyl silicone oil and ferrocenyl intercalated talc are weighed according to weight percentages of 83-94% and 6-17% respectively and stirred for 20-30 minutes to prepare passivation liquid, and then the passivation liquid is loaded into the passivation processor and the passivation liquid storage tank; at the same time, an automatic filling mechanism is set to automatically fill the passivation liquid into the passivation processor; S2: Heating, extrusion and passivation of calcium wire: Start the production system, heat the pure calcium rod to the plastic extrusion molding temperature, and then extrude it into a 6-8mm metal calcium wire through an extruder. The mass fraction of Ca in the obtained calcium wire is ≥98%; S3: Subsequently, the metal calcium wire enters the passivation treatment device filled with passivation liquid, and leaves after being coated with a layer of passivation film on the surface; coating treatment of the calcium wire: the metal calcium wire after the passivation treatment is coated with a low-carbon steel strip on the cored wire unit to form an alloy cored wire.

9. The deep purification and smelting method of high purity steel according to claim 8, characterized in that: The preparation method of the ferrocenyl intercalated talc is as follows: T1: Prepare a solution: Disperse 100-120 parts of talc and 0.3-0.8 parts of γ-mercaptopropyltrimethoxysilane in 1000-1200 parts of water by weight, stir and react at 80-90°C for 2-5 hours to prepare a suspension; T2: Add 10-16 parts of sodium p-styrene sulfonate, 0.5-2.6 parts of N-ferrocenyl-maleimide, and 3-6 parts of sodium hydroxide to 100-200 parts of water, and gradually add to the T1 talc suspension, and stir and react at 60-70°C for 60-100 hours; T3: Filtration and drying: After the reaction is completed, the solid is filtered out, washed, and dried to obtain talc powder treated with organic intercalation.

10. The deep purification and smelting method of high purity steel according to claim 8, characterized in that: When the pure calcium cored wire is treated with calcium, a 20-40 cm hole is opened on the crust slag surface near the downcomer of the RH vacuum furnace, and then the seamless pure calcium wire is fed through the hole. The wire feeding height is 20-50 cm, the wire feeding speed is 1.5-3.5 m / s, and the wire feeding amount is 1.3-2.0 m / ton of steel.

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