CN114959487A - Low-hydrogen low-nitrogen high-strength steel and smelting process thereof - Google Patents
Low-hydrogen low-nitrogen high-strength steel and smelting process thereof Download PDFInfo
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/16—Remelting metals
- C22B9/18—Electroslag remelting
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- C22C33/06—Making ferrous alloys by melting using master alloys
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Abstract
The invention relates to low-hydrogen low-nitrogen high-strength steel and a smelting process thereof, which comprises the following working procedures: (1) selecting ingredients and controlling the content of harmful elements; (2) smelting in an induction furnace, wherein the raw material has definite components, less corrosion, dryness and no humidity, the components and the temperature meet the requirements, and tapping is added into a ladle furnace; (3) argon blowing and refining in a ladle furnace, heating, deoxidizing, adjusting alloy components, and blowing argon and feeding aluminum wires for reinforced deoxidation; (4) after vacuum degassing, detecting the content of hydrogen, oxygen and nitrogen, blowing argon and feeding calcium wire to further change the shape of impurities, and then, ladle die casting to form an electrode blank with qualified components; (5) electroslag of the electrode blank into an electroslag ingot under the protection of argon; the high-strength steel manufactured by the process has low hydrogen and nitrogen contents, and the general porosity level is less than or equal to 1.0 level, so that the requirements of products on hydrogen and nitrogen can be met, the production cost can be reduced, the macrostructure of the steel can be improved, and the strength can be greatly improved.
Description
Technical Field
The invention belongs to the technical field of steel making, and particularly relates to low-hydrogen low-nitrogen high-strength steel which can meet the requirements of products on hydrogen and nitrogen, can reduce the production cost and improve the macrostructure of steel, and has greatly improved strength, and a smelting process thereof.
Background
The 30CrMnSiNi2A steel belongs to high-strength and high-toughness steel, the conventional smelting method comprises electric arc furnace smelting, vacuum refining, die casting and argon protection electroslag remelting, and the process route has high production cost, often has low-power incompatibility and low strength, and products cannot be delivered according to schedule; according to the production practice of many years, when [ H ] in the steel is less than or equal to 0.5PPm and [ N ] in the steel is less than or equal to 70PPm, and the solidification of the steel in the electroslag process is improved, the macrostructure of the steel can be effectively improved, and the strength is greatly improved. Meanwhile, the 30CrMnSiNi2A steel forging can generate a large amount of returned steel stub bars in the production process, so that the stock backlog is serious, and in order to quickly consume the stock stub bars, the 30CrMnSiNi2A steel forging is produced by adopting the processes of smelting in an induction furnace, vacuum refining, die casting and argon protection electroslag remelting, so that the macrostructure of steel is improved, and the strength can meet the requirement.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide the low-hydrogen low-nitrogen high-strength steel and the smelting process thereof, the steel [ H ] smelted by the process is less than or equal to 0.5PPm, and [ N ] is less than or equal to 70PPm, and the prepared 30CrMnSiNi2A steel forging has high strength and the macroscopic structure meets the standard requirement.
The purpose of the invention is realized by the following steps:
the low-hydrogen low-nitrogen high-strength steel comprises the following chemical components in percentage by weight: 0.27-0.34% of C, 0.90-1.20% of Si, 1.00-1.30% of Mn, 0.90-1.20% of Cr0.40-1.80% of Nis, less than or equal to 0.025% of P, less than or equal to 0.015% of S, less than or equal to 0.15% of Mo, less than or equal to 0.20% of W, less than or equal to 0.05% of V, less than or equal to 0.03% of Ti, less than or equal to 0.25% of Cu, and the balance of Fe.
The low-hydrogen low-nitrogen high-strength steel is optimally selected from the following components in percentage by weight: 0.27-0.31% of C, 0.95-1.05% of Si, 1.10-1.30% of Mn, 0.90-1.10% of Cr, 1.40-1.60% of Ni, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.08-0.15% of Mo, less than or equal to 0.10% of Cu, less than or equal to 0.035% of Al, less than or equal to 0.20% of W, less than or equal to 0.05% of V, less than or equal to 0.01% of Ti, and less than or equal to 0.020% of total of five-harmful elements As + Sn + Pb + Sb + Bi.
The invention also adopts the following technical scheme: a smelting process of low-hydrogen low-nitrogen high-strength steel comprises the following steps:
step 1), selecting ingredients, and controlling chemical components: the raw material for smelting the induction furnace is one of Cr-Ni steel stub bars or steel scraps, ferrosilicon, ferromanganese and ferrochromium, the surface of the raw material is required to be clean and free of oil stains, the specification of the raw material is less than or equal to phi 800mm, the length of the raw material is less than or equal to 1500mm, the raw material is used before being used, chemical components are detected by a portable spectrometer one by one, the components of the raw material entering the furnace meet the use requirement, the [ C ] is less than or equal to 0.20 percent and [ P ] is less than or equal to 0.015 percent after being melted down, the rest components do not exceed the upper limit of the process requirement, and the total content of harmful elements As + Sn + Pb + Sb + Bi is less than or equal to 0.020 percent;
step 2), during smelting of an induction furnace, filling 20-30 kg of lime into the bottom of the furnace, selecting the lime to confirm that no carbon block or sundries exist, tightening and loosening the charging material, enabling the direction of the charging material to be consistent with the longitudinal direction of the furnace, not allowing the long charging material to be transversely or obliquely placed in the furnace, and filling the charging material; adding 1-1.5 kg/t of Ca-Si powder or aluminum powder into the induction furnace before tapping of the induction furnace to deoxidize furnace slag, and inserting 1.0-2.0kg/t of aluminum into the induction furnace before tapping to deoxidize molten steel; tapping at the temperature of 1580-1620 ℃, and adding the tapped steel into a ladle furnace after the tapping condition is met;
step 3), after the ladle furnace is in place, firstly connecting argon to carry out bottom blowing argon stirring, controlling the argon flow to be 100 plus 110NL/min, heating and refining at the temperature of 2-3 ℃ L/min, adjusting the temperature to be more than or equal to 1550 ℃, adding 2.0-3.0Kg/t of lime and 0.5-1.0Kg/t of fluorite to adjust the slag quantity, adding 1.0-2.0Kg/t of calcium carbide, 1.0-2.0Kg/t of carbon powder deoxidizer and 1.0-3.0 Kg/t of ferrosilicon powder deoxidizer after slag is melted, transmitting electricity to melt slag, measuring the temperature, sampling and adjusting chemical components after slag is white, and blowing argon and feeding an aluminum wire according to the slag condition to be 1.0-3.0 m/t; during the refining, 0.5-1.0kg/t of carbon powder, 1.0-2.0kg/t of ferrosilicon powder deoxidizing agent and 0.5-1.0kg/t of aluminum powder are used for deoxidizing in small batches and multiple batches, and the reducing atmosphere is kept, so that the uniform temperature of the components is ensured; finely adjusting the alloy after white slag is remained for more than or equal to 20 minutes, sampling and analyzing the total components, ensuring white slag ladle before VD conversion, feeding an aluminum wire by argon blowing for 2.0-4.0 m/t, and controlling the residual Al to be 0.020-0.050%;
step 4), the hoisting ladle enters a vacuum tank at the temperature of more than or equal to 1650 ℃; hoisting the steel ladle into a vacuum tank, then connecting argon, covering a vacuum cover, keeping the steel ladle for more than or equal to 15 minutes at the pressure of less than or equal to 0.67mbar, then sampling and detecting components and gas content after relieving the vacuum pressure, determining hydrogen and oxygen on line, controlling the content of [ H ] to be less than or equal to 0.4ppm and the content of [ O ] to be less than or equal to 5.0ppm, sampling a glass tube, analyzing the nitrogen content, and controlling the content of [ N ] to be less than or equal to 40 ppm; controlling residual [ Al ] to be 0.020-0.040%; feeding a calcium wire at a speed of 0.1-0.3 m/t for calcium treatment, wherein the wire feeding speed is 120m/min, and the argon blowing weak stirring time is more than or equal to 12 minutes after feeding; temperature of the crane ladle: 1540 to 1550 ℃;
step 5) carefully selecting a casting blank mold with good inner wall quality before production arrangement, polishing and cleaning the inner wall, and cleaning and drying a pouring system by using a refractory material; filling argon into each casting blank mould for 2-3 minutes before casting, putting the casting blank mould into an injection pipe after filling the argon, and closing an argon valve 3 minutes before casting; argon protection pouring is carried out in the whole pouring process; the calming time is more than or equal to 5 minutes, and when the electrode blank is poured, a heat insulation cap, carbon-free protective slag and carbonized rice hulls are added to ensure the feeding effect; the casting temperature is as follows: 1530-1540 ℃; the pouring speed is controlled according to the middle and lower limits; cutting off a dead head after demoulding, and carrying out hot electroslag feeding or annealing;
step 6), before electroslag remelting, polishing the surface of the electrode blank to remove rust or performing shot blasting treatment to achieve smooth surface, baking the electrode blank at 600 ℃ for more than 4h before electroslag remelting, and drying slag used for electroslag remelting at 800 ℃ for 6h to prevent the excessive hydrogen in steel caused by water in the slag; the electroslag system is produced by adopting a ternary slag system, and comprises the following chemical components in percentage by weight: al2O 3: CaO = 65: 20: 15, lime part is replaced by pre-melted slag; in the electroslag remelting process, argon is continuously filled into an upper opening of a crystallizer for protection, the gas suction and hydrogen increase of a slag pool are prevented, the humidity of the atmosphere above the slag pool is further reduced, the hydrogen absorption and nitrogen absorption in the electroslag process are reduced, and 50-60g of calcium silicate powder is added every 5 minutes in the remelting process to deoxidize the slag; electroslag processing the electrode blank into electroslag ingot.
The invention has the following beneficial effects:
the invention ensures that [ H ] is less than or equal to 0.5PPm and [ N ] is less than or equal to 70PPm in finished steel by optimizing ingredients, smelting in an induction furnace, blowing argon in a ladle furnace for refining and feeding aluminum wires, vacuum degassing and electroslag of an electrode blank under the protection of argon, and the manufactured steel forging for a certain shell has good surface quality and high strength, has a macrostructure meeting the standard requirement, and detects the [ H ] of 0.4-0.5PPm and the [ N ] of 50-65PPm after forging.
Detailed Description
Example 1: a smelting process of low-hydrogen low-nitrogen high-strength steel comprises the following steps:
step 1), selecting ingredients, and controlling chemical components: the raw materials for smelting the induction furnace are Cr-Ni steel stub bars or steel scraps, ferrosilicon, ferromanganese, ferrochrome and other alloys, the surface of the raw materials is required to be clean and free of oil stains, the specification of the raw materials is less than or equal to phi 800mm, the length is less than or equal to 1500mm, the Cr-Ni steel stub bars are used before being detected by a hand spectrometer, the components of the Cr-Ni steel stub bars or steel scraps, ferrosilicon, ferromanganese and ferrochrome in the furnace meet the use requirements, the components of [ C ] is less than or equal to 0.20%, the [ P ] is less than or equal to 0.015%, the rest components do not exceed the upper limit of the process requirements, and the total sum of the harmful elements As + Sn + Pb + Sb + Bi is less than or equal to 0.020%;
step 2), during smelting of an induction furnace, filling 20-30 kg of lime into the bottom of the furnace, selecting the lime to confirm that no carbon block or sundries exist, tightening and loosening the charging material, enabling the direction of the charging material to be consistent with the longitudinal direction of the furnace, not allowing the long charging material to be transversely or obliquely placed in the furnace, and filling the charging material; adding 1-1.5 kg/t of Ca-Si powder or aluminum powder into the induction furnace before tapping of the induction furnace to deoxidize furnace slag, and inserting 1.0-2.0kg/t of aluminum into the induction furnace before tapping to deoxidize molten steel; tapping at the temperature of 1580-1620 ℃, and adding the tapped steel into a ladle furnace after the tapping condition is met;
step 3), after the ladle furnace is in place, firstly connecting argon to carry out bottom blowing argon stirring, controlling the argon flow to be 100 plus 110NL/min, heating and refining at the temperature of 2-3 ℃ L/min, adjusting the temperature to be more than or equal to 1550 ℃, adding 2.0-3.0Kg/t of lime and 0.5-1.0Kg/t of fluorite to adjust the slag quantity, adding 1.0-2.0Kg/t of calcium carbide, 1.0-2.0Kg/t of carbon powder deoxidizer and 1.0-3.0 Kg/t of ferrosilicon powder deoxidizer after slag is melted, transmitting electricity to melt slag, measuring the temperature, sampling and adjusting chemical components after slag is white, and blowing argon and feeding an aluminum wire according to the slag condition to be 1.0-3.0 m/t; during the refining, 0.5-1.0kg/t of carbon powder, 1.0-2.0kg/t of ferrosilicon powder deoxidizing agent and 0.5-1.0kg/t of aluminum powder are used for deoxidizing in small batches and multiple batches, and the reducing atmosphere is kept, so that the uniform temperature of the components is ensured; finely adjusting the alloy after white slag is remained for more than or equal to 20 minutes, sampling and analyzing the total components, ensuring white slag ladle before VD conversion, feeding an aluminum wire by argon blowing for 2.0-4.0 m/t, and controlling the residual Al to be 0.020-0.050%;
step 4), the hoisting ladle enters a vacuum tank at the temperature of more than or equal to 1650 ℃; hoisting the steel ladle into a vacuum tank, then connecting argon, covering a vacuum cover, keeping the steel ladle for more than or equal to 15 minutes at the pressure of less than or equal to 0.67mbar, then sampling and detecting components and gas content after relieving the vacuum pressure, determining hydrogen and oxygen on line, controlling the content of [ H ] to be less than or equal to 0.4ppm and the content of [ O ] to be less than or equal to 5.0ppm, sampling a glass tube, analyzing the nitrogen content, and controlling the content of [ N ] to be less than or equal to 40 ppm; controlling residual [ Al ] to be 0.020-0.040%; feeding a calcium wire at a speed of 0.1-0.3 m/t for calcium treatment, wherein the wire feeding speed is 120m/min, and the argon blowing weak stirring time is more than or equal to 12 minutes after feeding; temperature of the crane ladle: 1540 to 1550 ℃;
step 5) carefully selecting a casting blank mold with good inner wall quality before production arrangement, polishing and cleaning the inner wall, and cleaning and drying a pouring system by using a refractory material; filling argon into each casting blank mould for 2-3 minutes before casting, putting the casting blank mould into an injection pipe after filling the argon, and closing an argon valve 3 minutes before casting; argon protection pouring is carried out in the whole pouring process; the calming time is more than or equal to 5 minutes, and when the electrode blank is poured, a heat insulation cap, carbon-free protective slag and carbonized rice hulls are added to ensure the feeding effect; casting temperature: 1530-1540 ℃; the pouring speed is controlled according to the middle and lower limits; cutting off a dead head after demoulding, and carrying out hot electroslag feeding or annealing;
step 6), before electroslag remelting, polishing the surface of the electrode blank to remove rust or performing shot blasting treatment to achieve smooth surface, baking the electrode blank at 600 ℃ for more than 4h before electroslag remelting, and drying slag used for electroslag remelting at 800 ℃ for 6h to prevent the excessive hydrogen in steel caused by water in the slag; the electroslag system is produced by adopting a ternary slag system, and comprises the following chemical components in percentage by weight: al2O 3: CaO = 65: 20: 15, lime is replaced by pre-melted slag; in the electroslag remelting process, argon is continuously filled into an upper opening of a crystallizer for protection, the gas suction and hydrogen increase of a slag pool are prevented, the humidity of the atmosphere above the slag pool is further reduced, the hydrogen absorption and nitrogen absorption in the electroslag process are reduced, and 50-60g of calcium silicate powder is added every 5 minutes in the remelting process to deoxidize the slag; electroslag processing the electrode blank into electroslag ingot.
The following table shows the component comparison of the high-strength steel produced by different production modes of induction furnace smelting die casting and electric arc furnace smelting die casting, and the result shows that the low-hydrogen low-nitrogen high-strength steel produced by adopting the process disclosed by the invention has the components and gas content meeting the requirements, and the prepared 30CrMnSiNi2A steel forging has high strength and the macroscopic structure meeting the standard requirements.
Attached: chemical composition (m%) of low-hydrogen low-nitrogen high-strength steel
| Element(s) | M% of the target component | This embodiment | Electric arc furnace die casting process | Dry air electroslag process |
| C | 0.27-0.31 | 0.28 | 0.29 | 0.30 |
| Si | 0.95-1.05 | 1.00 | 1.10 | 1.05 |
| Mn | 1.00-1.30 | 1.20 | 1.15 | 1.08 |
| Cr | 0.90-1.10 | 1.00 | 1.05 | 0.95 |
| Ni | 1.40-1.60 | 1.50 | 1.55 | 1.47 |
| P | ≤0.015 | 0.007 | 0.012 | 0.013 |
| S | ≤0.005 | 0.002 | 0.003 | 0.005 |
| Mo | ≤0.15 | 0.11 | 0.08 | 0.07 |
| Cu | ≤0.10 | 0.05 | 0.06 | 0.07 |
| Al | ≤0.035 | 0.030 | 0.025 | 0.015 |
| W | ≤0.20 | 0.005 | 0.01 | 0.01 |
| V | ≤0.05 | 0.02 | 0.03 | 0.03 |
| Ti | ≤0.03 | 0.03 | 0.04 | 0.05 |
| As | ≤0.015 | 0.007 | 0.011 | 0.013 |
| Sn | ≤0.010 | 0.005 | 0.008 | 0.007 |
| Pb | ≤0.010 | 0.001 | 0.001 | 0.002 |
| Sb | ≤0.010 | 0.001 | 0.002 | 0.003 |
| Bi | ≤0.010 | 0.001 | 0.001 | 0.001 |
| [H]ppm | ≤0.5 | 0.45 | 0.70 | 0.90 |
| [O]ppm | ≤15 | 8.0 | 10.0 | 12.0 |
| [N]ppm | ≤70 | 56 | 70 | 78 |
| Rm（Mpa） | ≥1600 | 1700 | 1720 | 1690 |
| General porosity (grade) | ≤1.0 | 0.5 | 1.0 | 1.5 |
Claims (3)
1. The low-hydrogen low-nitrogen high-strength steel is characterized by comprising the following chemical components in percentage by weight: 0.27-0.34% of C, 0.90-1.20% of Si, 1.00-1.30% of Mn, 0.90-1.20% of Cr0.40-1.80% of Nis, less than or equal to 0.025% of P, less than or equal to 0.015% of S, less than or equal to 0.15% of Mo, less than or equal to 0.20% of W, less than or equal to 0.05% of V, less than or equal to 0.03% of Ti, less than or equal to 0.25% of Cu, and the balance of Fe.
2. The low-hydrogen low-nitrogen high-strength steel is characterized by being optimally selected from the following components in percentage by weight: 0.27-0.31% of C, 0.95-1.05% of Si, 1.10-1.30% of Mn, 0.90-1.10% of Cr, 1.40-1.60% of Ni, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.08-0.15% of Mo, less than or equal to 0.10% of Cu, less than or equal to 0.035% of Al, less than or equal to 0.20% of W, less than or equal to 0.05% of V, less than or equal to 0.01% of Ti, and less than or equal to 0.020% of total of five-harmful elements As + Sn + Pb + Sb + Bi.
3. A smelting process of the low-hydrogen low-nitrogen high-strength steel as claimed in claim 1 or 2, characterized by comprising the following steps:
step 1), selecting ingredients, and controlling chemical components: the raw material for smelting the induction furnace is one of Cr-Ni steel stub bars or steel scraps, ferrosilicon, ferromanganese and ferrochromium, the surface of the raw material is required to be clean and free of oil stains, the specification of the raw material is less than or equal to phi 800mm, the length of the raw material is less than or equal to 1500mm, the raw material is used before being used, chemical components are detected by a portable spectrometer one by one, the components of the raw material entering the furnace meet the use requirement, the [ C ] is less than or equal to 0.20 percent and [ P ] is less than or equal to 0.015 percent after being melted down, the rest components do not exceed the upper limit of the process requirement, and the total content of harmful elements As + Sn + Pb + Sb + Bi is less than or equal to 0.020 percent;
step 2) during smelting of the induction furnace, 20-30 kg of lime is filled in the bottom of the induction furnace, the lime is selected, no carbon block or sundries exist, the charging is tight at the bottom and loose at the top, the direction of the charging is consistent with the longitudinal direction of the furnace, the long charging is not allowed to be transversely or obliquely placed in the furnace, the furnace charge is filled and filled, a wood bar is used for prying or beating the raw material in the smelting process to prevent the raw material from bridging to generate high temperature, the temperature is 1560-1620 ℃ after the furnace charge of the induction furnace is melted down, the sample is taken, and the chemical components are checked according to the analysis result; adding 1-1.5 kg/t of Ca-Si powder or aluminum powder into the induction furnace before tapping of the induction furnace to deoxidize furnace slag, and inserting 1.0-2.0kg/t of aluminum into the induction furnace before tapping to deoxidize molten steel; tapping at the temperature of 1580-1620 ℃, and adding the tapped steel into a ladle furnace after the tapping condition is met;
step 3), after the ladle furnace is in place, firstly connecting argon to carry out bottom blowing argon stirring, controlling the argon flow to be 100 plus 110NL/min, heating and refining at the temperature of 2-3 ℃ L/min, adjusting the temperature to be more than or equal to 1550 ℃, adding 2.0-3.0Kg/t of lime and 0.5-1.0Kg/t of fluorite to adjust the slag quantity, adding 1.0-2.0Kg/t of calcium carbide, 1.0-2.0Kg/t of carbon powder deoxidizer and 1.0-3.0 Kg/t of ferrosilicon powder deoxidizer after slag is melted, transmitting electricity to melt slag, measuring the temperature, sampling and adjusting chemical components after slag is white, and blowing argon and feeding an aluminum wire according to the slag condition to be 1.0-3.0 m/t; during the refining, 0.5-1.0kg/t of carbon powder, 1.0-2.0kg/t of ferrosilicon powder deoxidizing agent and 0.5-1.0kg/t of aluminum powder are used for deoxidizing in small batches and multiple batches, and the reducing atmosphere is kept, so that the uniform temperature of the components is ensured; finely adjusting the alloy after white slag is remained for more than or equal to 20 minutes, sampling and analyzing the total components, ensuring white slag ladle before VD conversion, feeding an aluminum wire by argon blowing for 2.0-4.0 m/t, and controlling the residual Al to be 0.020-0.050%;
step 4), the crane ladle enters a vacuum tank at the temperature of more than or equal to 1650 ℃; hoisting the steel ladle into a vacuum tank, then connecting argon, covering a vacuum cover, keeping the steel ladle for more than or equal to 15 minutes at the pressure of less than or equal to 0.67mbar, then sampling and detecting components and gas content after relieving the vacuum pressure, determining hydrogen and oxygen on line, controlling the content of [ H ] to be less than or equal to 0.4ppm and the content of [ O ] to be less than or equal to 5.0ppm, sampling a glass tube, analyzing the nitrogen content, and controlling the content of [ N ] to be less than or equal to 40 ppm; controlling residual [ Al ] to be 0.020-0.040%; feeding a calcium wire at a speed of 0.1-0.3 m/t for calcium treatment, wherein the wire feeding speed is 120m/min, and the argon blowing weak stirring time is more than or equal to 12 minutes after feeding; temperature of the crane ladle: 1540 to 1550 ℃;
step 5) carefully selecting a casting blank mold with good inner wall quality before production arrangement, polishing and cleaning the inner wall, and cleaning and drying a pouring system by using a refractory material; filling argon into each casting blank mould for 2-3 minutes before casting, putting the casting blank mould into an injection pipe after filling the argon, and closing an argon valve 3 minutes before casting; argon protection pouring is carried out in the whole pouring process; the calming time is more than or equal to 5 minutes, and when the electrode blank is poured, a heat insulation cap, carbon-free protective slag and carbonized rice hulls are added to ensure the feeding effect; the casting temperature is as follows: 1530-1540 ℃; the pouring speed is controlled according to the middle and lower limits; cutting off a dead head after demoulding, and carrying out hot electroslag feeding or annealing;
step 6), before electroslag remelting, polishing the surface of the electrode blank to remove rust or performing shot blasting treatment to achieve smooth surface, baking the electrode blank at 600 ℃ for more than 4h before electroslag remelting, and drying slag used for electroslag remelting at 800 ℃ for 6h to prevent the excessive hydrogen in steel caused by water in the slag; the electroslag system is produced by adopting a ternary slag system, and comprises the following chemical components in percentage by weight: al2O 3: CaO = 65: 20: 15, lime is replaced by pre-melted slag; in the electroslag remelting process, argon is continuously filled into an upper opening of a crystallizer for protection, the gas suction and hydrogen increase of a slag pool are prevented, the humidity of the atmosphere above the slag pool is further reduced, the hydrogen absorption and nitrogen absorption in the electroslag process are reduced, and 50-60g of calcium silicate powder is added every 5 minutes in the remelting process to deoxidize the slag; electroslag processing the electrode blank into electroslag ingot.
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