Production method of wire converter square billet for producing ultralow-resistance wire

Abstract

The invention relates to a method for producing a wire converter square billet for producing an ultralow-resistance wire, which comprises the following steps of: smelting by adopting a 150t converter + LF + RH + 230mm * 1250mm * 3600mm continuous casting smelting process, and producing and manufacturing a converter process industrial pure iron slab; the produced industrial pure iron comprises the following chemical components in percentage by mass: less than or equal to 0.003% of C, less than or equal to 0.005% of Si, less than or equal to 0.030% of Mn, less than or equal to 0.005% of P, less than or equal to 0.005% of S, less than or equal to 0.005% of O, less than or equal to 0.02% of Cr, less than or equal to 0.02% of Ni, less than or equal to 0.02% of Cu, less than or equal to 0.020% of Al and less than or equal to 0.01% of Ti. According to the method, indexes such as chemical components and high steel purity of the converter process industrial pure iron plate blank are guaranteed, and the surface quality level of the converter plate blank industrial pure iron is also guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical manufacturing, and in particular relates to a production method for producing wire converter billets for ultra-low resistance wires. Background Art

[0002] Pure iron is an important basic raw material in steel materials. Its purity directly determines the performance of metal products. What technical means and R&D processes can be used to further improve the purity of pure iron is a research hotspot at home and abroad.

[0003] The purity of pure iron directly affects the quality of steel and even the safety of the work process of downstream steel users.

[0004] This invention develops industrial pure iron slabs with high steel purity, meeting the requirements for high-end steel products. This slab, produced using a 150t converter, LF, RH, and 230mm x 1250mm x 3600mm smelting process, meets the requirements for high-end steel products and represents a breakthrough in the converter slab process for mass production of industrial pure iron bars. Summary of the Invention

[0005] The present invention provides a production method for producing converter billets for ultra-low resistance conductors. The method adopts a 150t converter + LF + RH + 230mm×1250mm×3600mm continuous casting smelting process to produce converter process industrial pure iron slabs. This method not only ensures the chemical composition and high steel purity of the converter process industrial pure iron slabs, but also ensures the surface quality level of the converter slab industrial pure iron.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A production method for producing converter billets for ultra-low resistance wires, comprising desulfurization, converter smelting, LF furnace refining, RH refining, and slab continuous casting, specifically as follows:

[0008] 1) The converter smelting includes: adding 10-13 kg / t of lime and 10-13 kg / t of sintered return ore as padding before adding iron; when producing this type of steel, the previous heat is also carried out according to this process to improve the dephosphorization rate. No slag is left: when the previous furnace of this type of steel is slaged, the furnace body is rotated to 180-185 degrees, and the residual slag in the furnace is discharged. Double slag smelting is adopted: the amount of dolomite added is ≤10 kg / t, and 1 / 3-1 / 2 of the total amount of lime is added to the first batch of materials in 4-5 times. The slag discharge time is controlled within 4.5-5 minutes of blowing to improve the oxidizability and ensure the fluidity of the slag. As much slag as possible is discharged, the slag discharge amount is greater than 2 / 3, and the final slag basicity is controlled to 2.5-2.8; when the slag is discharged for the first time, the temperature is measured, steel samples and slag samples are taken for testing, and a dedicated person observes the slag discharge, and as much slag as possible is discharged while ensuring that no iron is discharged. Process temperature drop: Use iron balls and ore, add in small amounts in multiple batches, and add 2.0-3.2 kg / t each batch; converter end point: 0.5-0.6 min before the end of blowing, add 3.2-3.3 kg / t of ore. After the converter end point test, "spot blowing" for 40-60 seconds, perform slag discharge before tapping, and wait for sample tapping.

[0009] 2) The LF furnace refining process includes: preparing iron oxide scale in advance to control the oxygen content of the molten steel at the inlet station to ≤700ppm. Iron oxide scale is added during slag formation in batches of 1.1-10kg / t per batch, with the oxygen content of the molten steel controlled at 700-1000ppm. A low-flow argon gas permeability test is performed on the molten steel at the inlet station. Slag addition is primarily for submerged arc dephosphorization and manganese removal, using high-quality lime slag at a rate of 2.0-3.2kg / t per batch, for a total of 5.5-6kg / t. At the end of each process, high-pressure argon stirring is performed for 3-4 minutes to promote dephosphorization and manganese removal. The treatment cycle is 30-35 minutes. Rapid temperature increase is performed to ensure the exit temperature of the molten steel, which is controlled at 1613-1627°C to avoid RH rise. After the power supply is terminated, the oxygen content is determined and no slag modification is performed.

[0010] 3) The RH refining includes: after the treatment of the previous furnace of the last furnace of the first two tank cleaning furnaces is completed, the steel is cooled and cleaned to clean the steel stuck under the suction nozzle. Oxygen is determined upon entering the station. If the oxygen content is insufficient, oxygen needs to be supplemented. If the temperature is insufficient, oxygen is blown to heat the aluminum to avoid heating after the deoxidation is completed. The oxygen content during heating is calculated separately. After the oxygen supplement is completed, the oxygen is determined again to confirm whether the oxygen content is sufficient. The target oxygen value is 550-600ppm; for deep vacuum decarburization, the initial circulating gas flow rate is 900-1100NL / min, and 1600-1700NL / min when the vacuum degree is ≤100Pa; decarburization time: deep vacuum ≥15min; after the RH deep decarburization is completed, the target oxygen is controlled at 500-700ppm; deoxidation alloying: after the decarburization is completed, aluminum particles are used for deoxidation alloying, and the target aluminum leaving the station is 0.020%-0.030%, and other elements are not totalized; the RH net circulation time is ≥10min; the temperature target leaving the station: the continuous pouring temperature is 1582-1596℃; the molten steel calming time is ≥20min.

[0011] 4) The slab continuous casting process includes: continuous casting billet size of 230mm×1250mm×3600mm. Before baking the tundish, the impact tank and residual refractory materials and debris in the tundish must be cleaned. Before production, the protective casting system must be inspected to confirm that the argon equipment is intact and the pipelines are unobstructed. The external sleeve must be well sealed and casting without a sealing ring is strictly prohibited. The bowl of the protective sleeve must be perpendicular to the water inlet. If the sealing ring is damaged, it must be replaced. The continuous casting speed is 0.85-0.90m / min; 5-6t of molten steel must be left in the casting ladle to prevent slag from falling from the ladle. A carbon-free covering agent is used in the continuous casting tundish, and ultra-low carbon protective slag is used as the protective slag. One low-magnification sample and a gas sample from the tundish are taken for inspection. The purity of the billets with qualified composition is maintained, and the quality inspection of the billets is strengthened. Only after the billets are confirmed to be of qualified quality can they be rolled.

[0012] The chemical composition of the raw material molten iron used in the present invention is as follows by mass percentage: P: ≤0.050%, S: ≤0.030%, Si: 0.30% to 0.050%, Mn: ≤0.08%, Ti: ≤0.05%, Cr: ≤0.0060%, Ni: ≤0.0035%, Cu: ≤0.0025%; the molten iron temperature is ≥1300°C, and S is ≤0.0020% after the molten iron is desulfurized.

[0013] The physical and chemical indicators of the lime used in the present invention are: activity ≥ 320 ml, S ≤ 0.015%, CaO ≥ 90%. The physical and chemical indicators of dolomite are: S ≤ 0.020%. The physical and chemical indicators of sintered return ore are: S ≤ 0.020%.

[0014] The chemical composition of the industrial pure iron produced by the method of the present invention is as follows by mass percentage: C: ≤0.003%, Si: ≤0.005%, Mn: ≤0.030%, P: ≤0.005%, S: ≤0.005%, O: ≤0.005%, Cr: ≤0.02%, Ni: ≤0.02%, Cu: ≤0.02%, Al: ≤0.020%, and Ti: ≤0.01%.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The 150t converter + LF + RH + 230mm × 1250mm × 3600mm smelting process is used to produce industrial pure iron slabs, which meets the standard chemical composition requirements and ensures the purity of the steel.

[0017] 2) Reasonable component design and production process ensure surface quality and internal quality.

[0018] 3) The chemical composition, steel purity and surface quality of the finished steel meet the requirements of high-end products. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention will be further described below with reference to the examples.

[0020] Process route: Desulfurization (deep desulfurization, mirror slag removal) → Converter (top and bottom combined blowing, double slag process) → LF (dephosphorization) → RH (decarburization) → Slab Caster. The scrap steel used in this invention is guaranteed to have a low alloying element content and is clean, low-phosphorus, low-sulfur, cold-rolled base steel. Elements such as Cr, Ni, and Cu are strictly prohibited.

[0021] Example 1:

[0022] The process route of this embodiment is: desulfurization (deep desulfurization, mirror slag removal) → converter (top and bottom combined blowing, double slag process) → LF (dephosphorization) → RH (decarburization) → slab caster.

[0023] 1) Raw material requirements:

[0024] ① Molten iron composition: P: 0.030%, S: 0.025%, Si: 0.35%, Mn: 0.05%, Ti: 0.03%, Cr: 0.0050%, Ni: 0.0025%, Cu: 0.0020%. Molten iron temperature: 1450°C. After desulfurization, S: 0.0010%.

[0025] ② Scrap steel: low alloy element content, clean scrap steel (low phosphorus and low sulfur cold-rolled base material scrap steel), strictly prohibited from containing Cr, Ni, Cu and other elements.

[0026] ③ Slag making materials: High-quality lime: activity 380ml, S: 0.010%, CaO: 93%. Dolomite: S: 0.010%. Sintered ore: S: 0.010%. Limestone: S: 0.012%.

[0027] 2) Converter smelting:

[0028] Before adding iron, 11kg / t of lime and 11kg / t of sintered return ore are added as padding. For this steel type, the previous heat should also follow this process to improve dephosphorization efficiency. No slag retention: When slag is dumped from the previous heat, the furnace is rotated 180° to remove all residual slag. Double-slag smelting: 8kg / t of dolomite is used. Approximately 1 / 3 of the total lime volume (including lime added before iron addition) is added to the first batch of smelting material in five batches. The slag tapping time is controlled within 4.5 minutes of blowing to improve oxidizability and ensure slag fluidity. As much slag as possible is tapped (greater than 2 / 3 of the slag volume), resulting in a final slag basicity of 2.6. During the first slag tapping, the temperature is measured, and steel and slag samples are taken for testing. A dedicated person observes the slag tapping process, and as much slag as possible is tapped while ensuring no iron is released. Process temperature reduction: Iron balls and ore are added in small, multiple batches of 2.5kg / t. Converter end point: 0.5 min before the end of blowing, add 3.2 kg / t of ore. After the converter end point test, "spot blowing" for 50 seconds, perform slag discharge before tapping, and wait for sample tapping.

[0029] 3) LF furnace:

[0030] Oxide scale is prepared in advance to control the oxygen content of the incoming molten steel at 600ppm. Oxide scale is added during slag formation in batches of 10kg / t each, with the oxygen content of the molten steel controlled at 800ppm. A low-flow argon gas flow test is performed on the incoming molten steel to test its permeability. Slag addition is primarily for submerged arc dephosphorization and manganese removal. High-quality lime slag is used, at a rate of 2.6kg / t per batch, for a total of approximately 5.5kg / t. At the end of each process, high-pressure argon agitation is applied for 3 minutes to promote dephosphorization and manganese removal. The treatment cycle is 32 minutes, with rapid temperature increase to ensure the exit temperature is controlled at 1620°C to avoid RH rise. After the power supply is terminated, the oxygen level is determined and no slag modification is performed.

[0031] 4)RH refining:

[0032] After the last heat of the first two tank cleaning heats is cleaned, the steel is cooled and the steel stuck under the suction nozzle is cleaned. Oxygen levels are measured upon entry. If oxygen levels are insufficient, oxygen is added. If the temperature is insufficient, oxygen is blown through the alumina to increase the temperature after deoxidation is complete. The oxygen level is calculated separately for heating. After oxygen replenishment, oxygen is re-measured to confirm sufficiency. The target oxygen level is 570 ppm. Deep vacuum decarburization is performed, with a circulating gas flow rate starting at 950 NL / min and increasing to 1600 NL / min at a vacuum of 90 Pa. Decarburization time: 20 minutes in deep vacuum. RH deep decarburization is completed, with an oxygen target of 600 ppm. Deoxidation and alloying: After decarburization, aluminum pellet deoxidation and alloying are performed, with a target aluminum content of 0.024% at the exit. No other element addition is performed. RH net cycle time is 14 minutes. The target temperature at the exit is 1590°C for continuous pouring. The steel cooling time is 24 minutes.

[0033] 5) Continuous casting: The continuous casting billet size is 230mm×1250mm×3600mm. Before baking the tundish, clean the impact groove, residual refractory materials and debris in the tundish. Before production, check the protective casting system to confirm that the argon equipment is intact and the pipeline is unobstructed. The external sleeve is well sealed and casting without a sealing ring is strictly prohibited. The bowl of the protective sleeve is perpendicular to the water inlet. If the sealing ring is damaged, it must be replaced. Casting speed: 0.87m / min. There are 5t of molten steel left in the casting ladle to prevent slag from falling from the ladle. The continuous casting tundish has no carbon covering agent, and the protective slag should be ultra-low carbon protective slag. Take one low-magnification sample and a gas sample from the tundish for inspection. The purity of the billet with qualified composition is maintained, and the quality inspection of the billet is strengthened. Rolling can only be carried out after confirming that the billet quality is qualified.

[0034] The composition of industrial pure iron in the slab process of this embodiment is: C: 0.0015%, Si: 0.002%, Mn: 0.015%, P: 0.001%, S: 0.002%, O: 0.003%, Cr: 0.01%, Ni: 0.01%, Cu: 0.012%, Al: 0.014%, and Ti: 0.008%.

[0035] Example 2:

[0036] The process route of this embodiment is: desulfurization (deep desulfurization, mirror slag removal) → converter (top and bottom combined blowing, double slag process) → LF (dephosphorization) → RH (decarburization) → slab caster.

[0037] 1) Raw material requirements:

[0038] ① Molten iron: P: 0.030%, S: 0.020%, Si: 0.040%, Mn: 0.04%, Ti: 0.04%, Cr: 0.0050%, Ni: 0.0028%, Cu: 0.0020%. Molten iron temperature 1440℃, S: 0.0015% after desulfurization.

[0039] ② Scrap steel: low alloy element content, clean scrap steel (low phosphorus and low sulfur cold-rolled base material scrap steel), strictly prohibited from containing Cr, Ni, Cu and other elements.

[0040] ③ Slag material: High-quality lime: activity 400ml, S: 0.012%, CaO: 94%. Dolomite: S: 0.015%. Sintered ore: S: 0.016%.

[0041] 2) Converter smelting:

[0042] Before adding iron, 12kg / t of lime and 12kg / t of sintered return ore are added as padding. For this steel, the previous heat should also follow this process to improve dephosphorization efficiency. No slag retention: When slag is dumped from the previous heat, the furnace is rotated 180° to remove all residual slag. Double-slag smelting: 7kg / t of dolomite is used. Approximately 1 / 3 of the total lime content (including lime added before iron addition) is added to the first batch of smelting material in five batches. The slag tapping time is controlled within 5 minutes of blowing to improve oxidizability and ensure slag fluidity. As much slag as possible (>2 / 3 of the slag volume) is tapped, resulting in a final slag basicity of 2.6. During the first slag tapping, temperature is measured, and steel and slag samples are collected for testing. A dedicated person is on hand to observe the slag tapping process, ensuring that as much slag as possible is tapped while ensuring iron is not released. Process temperature reduction: Iron balls and ore are added in small, multiple batches of 2.5kg / t. Converter end point: 0.5 min before the end of blowing, add 3.2 kg / t of ore. After the converter end point test, "spot blowing" for 50 seconds, perform slag discharge before tapping, and wait for sample tapping.

[0043] 3) LF furnace:

[0044] Oxide scale is prepared in advance to control the oxygen content of the incoming molten steel at 600ppm. Oxide scale is added during slag formation in batches of 10kg / t each, with the oxygen content of the molten steel controlled at 800ppm. A low-flow argon gas flow test is performed on the incoming molten steel to test its permeability. Slag addition is primarily for submerged arc dephosphorization and manganese removal. High-quality lime slag is used, at a rate of 2.6kg / t per batch, for a total of approximately 5.5kg / t. At the end of each process, high-pressure argon agitation is applied for 3 minutes to promote dephosphorization and manganese removal. The treatment cycle is 32 minutes, with rapid temperature increase to ensure the exit temperature is controlled at 1618°C to avoid RH rise. After the power supply is terminated, oxygen is determined and no slag modification is performed.

[0045] 4)RH refining:

[0046] After the last heat of the first two tank cleaning heats is cleaned, the steel is cooled and the steel stuck under the suction nozzle is cleaned. Oxygen levels are measured upon entry. If oxygen levels are insufficient, oxygen is added. If the temperature is insufficient, oxygen is blown through the alumina to increase the temperature after deoxidation is complete. The oxygen level is calculated separately for heating. After oxygen replenishment, oxygen is re-measured to confirm sufficiency. The target oxygen level is 570 ppm. Deep vacuum decarburization is performed, with a circulating gas flow rate starting at 970 NL / min and rising to 1650 NL / min at a vacuum of 90 Pa. Decarburization time: 16 minutes in deep vacuum. RH deep decarburization is completed, with an oxygen target of 600 ppm. Deoxidation and alloying: After decarburization, aluminum pellet deoxidation and alloying are performed, with a target aluminum content of 0.027% at the exit. No other element addition is performed. RH net circulation time is 13 minutes. The target temperature at the exit is 1588°C for continuous pouring. The steel cooling time is 25 minutes.

[0047] 5) Continuous casting: The continuous casting billet size is 230mm×1250mm×3600mm. Before baking the tundish, clean the impact groove, residual refractory materials and debris in the tundish. Before production, check the protective casting system to confirm that the argon equipment is intact and the pipeline is unobstructed. The external sleeve is well sealed and casting without a sealing ring is strictly prohibited. The bowl of the protective sleeve is perpendicular to the water inlet. If the sealing ring is damaged, it must be replaced. Casting speed: 0.87m / min. There are 5t of molten steel left in the casting ladle to prevent slag from falling from the ladle. The continuous casting tundish has no carbon covering agent, and the protective slag should be ultra-low carbon protective slag. Take one low-magnification sample and a gas sample from the tundish for inspection. The purity of the billet with qualified composition is maintained, and the quality inspection of the billet is strengthened. Rolling can only be carried out after confirming that the billet quality is qualified.

[0048] The composition of industrial pure iron in the slab process of this embodiment is: C: 0.002%, Si: 0.002%, Mn: 0.020%, P: 0.003%, S: 0.003%, O: 0.003%, Cr: 0.014%, Ni: 0.01%, Cu: 0.01%, Al: 0.015%, and Ti: 0.007%.

[0049] Example 3:

[0050] The process route of this embodiment is: desulfurization (deep desulfurization, mirror slag removal) → converter (top and bottom combined blowing, double slag process) → LF (dephosphorization) → RH (decarburization) → slab caster.

[0051] 1) Raw material requirements:

[0052] ① Molten iron: P: 0.030%, S: 0.020%, Si: 0.38%, Mn: 0.04%, Ti: 0.03%, Cr: 0.0040%, Ni: 0.0025%, Cu: 0.0020%. Molten iron temperature 1420℃, S: 0.0014% after desulfurization.

[0053] ② Scrap steel: low alloy element content, clean scrap steel (low phosphorus and low sulfur cold-rolled base material scrap steel), strictly prohibited from containing Cr, Ni, Cu and other elements.

[0054] ③ Slag material: High-quality lime: activity 380ml, S: 0.012%, CaO: 93%. Dolomite: S: 0.016%. Sintered ore: S: 0.014%.

[0055] 2) Converter smelting:

[0056] Before adding iron, 11kg / t of lime and 11kg / t of sintered return ore are added as padding. For this steel, the previous heat should also follow this process to improve dephosphorization efficiency. No slag retention: When slag is dumped from the previous heat, the furnace is rotated 180° to remove all residual slag. Double-slag smelting: 8kg / t of dolomite is used. Approximately 1 / 3 of the total lime content (including lime added before iron addition) is added to the first batch of smelting material in four batches. The slag tapping time is controlled within 4.5 minutes of blowing to improve oxidizability and ensure slag fluidity. As much slag as possible (>2 / 3 of the slag volume) is tapped, resulting in a final slag basicity of 2.6. During the first slag tapping, temperature measurement is performed, and steel and slag samples are collected for testing. A dedicated person is on hand to observe the slag tapping process, ensuring that as much slag as possible is tapped without causing iron buildup. Process temperature reduction: Iron balls and ore are added in small, multiple batches of 2.7kg / t. Converter end point: 0.5 min before the end of blowing, add 3.2 kg / t of ore. After the converter end point test, "spot blowing" for 55 seconds, perform slag discharge before tapping, and wait for sample tapping.

[0057] 3) LF furnace:

[0058] Oxide scale is prepared in advance to control the oxygen content of the incoming molten steel at 600ppm. Oxide scale is added during the slag-making process in batches of 10kg / t. The oxygen content of the molten steel is controlled at 800ppm. A low-flow argon gas flow test is performed on the incoming molten steel to test its permeability. Slag addition is primarily for submerged arc dephosphorization and manganese removal. High-quality lime slag is added at a rate of 2.7kg / t per batch, for a total of approximately 5.7kg / t. After each power-on process, high-pressure argon stirring is performed for 3 minutes to promote dephosphorization and manganese removal. The treatment cycle is 32 minutes, with rapid temperature increase to ensure the exit temperature is controlled at 1619°C to avoid RH rise. After power-on, oxygen is determined and no slag modification is performed.

[0059] 4)RH refining:

[0060] After the last heat of the first two tank cleaning heats is cleaned, the steel is cooled and the steel stuck under the suction nozzle is cleaned. Oxygen levels are measured upon entry. If oxygen levels are insufficient, oxygen is added. If the temperature is insufficient, oxygen is blown through the alumina to increase the temperature after deoxidation is complete. The oxygen level is calculated separately for heating. After oxygen replenishment, oxygen is re-measured to confirm sufficiency. The target oxygen level is 570 ppm. Deep vacuum decarburization is performed, with a circulating gas flow rate starting at 960 NL / min and increasing to 1600 NL / min at a vacuum of 80 Pa. Decarburization time: 18 minutes in deep vacuum. RH deep decarburization is completed, with an oxygen target of 600 ppm. Deoxidation and alloying: After decarburization, aluminum pellet deoxidation and alloying are performed, with a target aluminum content of 0.025% at the exit. No other element addition is performed. RH net cycle time is 13 minutes. The target temperature at the exit is 1590°C for continuous pouring. The steel cooling time is 24 minutes.

[0061] 5) Continuous casting: The continuous casting billet size is 230mm×1250mm×3600mm. Before baking the tundish, clean the impact groove, residual refractory materials and debris in the tundish. Before production, check the protective casting system to confirm that the argon equipment is intact and the pipeline is unobstructed. The external sleeve is well sealed and casting without a sealing ring is strictly prohibited. The bowl of the protective sleeve is perpendicular to the water inlet. If the sealing ring is damaged, it must be replaced. Casting speed: 0.88m / min. There are 5t of molten steel left in the casting ladle to prevent slag from falling from the ladle. The continuous casting tundish has no carbon covering agent, and the protective slag should be ultra-low carbon protective slag. Take one low-magnification sample and a gas sample from the tundish for inspection. The purity of the billet with qualified composition is maintained, and the quality inspection of the billet is strengthened. Rolling can only be carried out after confirming that the billet quality is qualified.

[0062] The composition of industrial pure iron in the slab process of this embodiment is: C: 0.002%, Si: 0.003%, Mn: 0.020%, P: 0.003%, S: 0.003%, O: 0.004%, Cr: 0.014%, Ni: 0.01%, Cu: 0.01%, Al: 0.014%, and Ti: 0.006%.

[0063] The test results of the finished products of Examples 1-3 are shown in Table 1, and two samples were taken for test data for each example.

[0064] Table 1 Macrostructure of Example Slab

[0065] Serial number Generally loose Loose center Ingot segregation Central segregation standard ≤1.0 ≤1.0 ≤1.0 ≤0.5 Example 1 0.5 0.5 0.5 0 Example 1 0.5 0.5 0.5 0 Example 2 0.5 0.5 0.5 0 Example 2 0.5 0.5 0.5 0 Example 3 0.5 0.5 0.5 0 Example 3 0.5 0.5 0.5 0

Claims

1. A method for producing converter billets for ultra-low resistance wires, comprising desulfurization, converter smelting, LF furnace refining, RH refining, and slab continuous casting, characterized in that: The LF furnace refining includes: controlling the oxygen content of the molten steel entering the station to ≤700ppm, adding iron oxide scale during the slag making process, adding the iron oxide scale in batches, adding 1.1-10kg / t each batch, controlling the oxygen value of the molten steel to 700-1000ppm; and controlling the temperature of the molten steel leaving the station to 1613-1627℃.

2. The method for producing a wire converter billet for ultra-low resistance conductor according to claim 1, characterized in that: The LF furnace refining uses lime slag material, with an addition amount of 2.0-3.2 kg / t per batch and a total amount of 5.5-6 kg / t. After each process is powered on, argon is stirred for 3-4 minutes, and the processing cycle is 30-35 minutes.

3. The method for producing a wire converter billet for ultra-low resistance conductor according to claim 1, characterized in that: The converter smelting includes: adding 10-13 kg / t of lime and 10-13 kg / t of sintered return ore as padding before adding iron; adopting double slag smelting: the amount of dolomite added is ≤10 kg / t, 1 / 3-1 / 2 of the total amount of lime is added to the first batch of smelting materials in 4-5 times, the slag tapping time is controlled within 4.5-5 minutes of blowing, and the final slag basicity is controlled at 2.5-2.8; the converter end point: 0.5-0.6 minutes before the end of blowing, 3.2-3.3 kg / t of ore is added, after the converter end point test, "spot blowing" is performed for 40-60 seconds, the slag tapping operation is performed before tapping, and the steel is tapped in a sample-like manner.

4. The method for producing a wire converter billet for ultra-low resistance conductor according to claim 1, wherein: The RH refining includes: oxygen setting upon entering the station, with a target oxygen value of 550-600 ppm; deep vacuum decarburization, with the circulating gas flow rate starting at 900-1100 NL / min and reaching 1600-1700 NL / min when the vacuum degree is ≤100 Pa; decarburization time: deep vacuum ≥15 min; RH deep decarburization is completed, with the target oxygen being controlled at 500-700 ppm; deoxidation and alloying: after decarburization is completed, aluminum particles are used for deoxidation and alloying, with the target aluminum leaving the station being 0.020%-0.030%, and no other elements are added; RH net circulation time ≥10 min; temperature target leaving the station: continuous pouring temperature is 1582-1596°C; and molten steel calming time ≥20 min.

5. The method for producing a wire converter billet for ultra-low resistance conductor according to claim 1, characterized in that: The slab continuous casting includes: a continuous casting speed of 0.85-0.90 m / min; 5-6 tons of molten steel remaining in the casting ladle to prevent slag from falling from the ladle; a carbon-free covering agent is used in the continuous casting tundish, and ultra-low carbon protective slag is used as the protective slag.

6. The method for producing a wire converter billet for ultra-low resistance conductor according to claim 1, characterized in that: The chemical composition of the raw material molten iron used is as follows by mass percentage: P: ≤0.050%, S: ≤0.030%, Si: 0.30%~0.050%, Mn: ≤0.08%, Ti: ≤0.05%, Cr: ≤0.0060%, Ni: ≤0.0035%, Cu: ≤0.0025%; the molten iron temperature is ≥1300℃, and the S content after desulfurization is ≤0.0020%.

7. A method for producing a wire converter billet for ultra-low resistance conductor according to claim 2 or 3, characterized in that: The physical and chemical indicators of the lime are: activity ≥320ml, S ≤0.015%, and CaO ≥90%.

8. The method for producing converter billets for ultra-low resistance conductors according to claim 3, characterized in that: The physical and chemical index of the dolomite is: S≤0.020%; the physical and chemical index of the sintered return ore is: S≤0.020%.

9. A method for producing converter billets for ultra-low resistance conductors according to any one of claims 1 to 8, characterized in that: The chemical composition of the industrial pure iron is as follows by mass percentage: C: ≤0.003%, Si: ≤0.005%, Mn: ≤0.030%, P: ≤0.005%, S: ≤0.005%, O: ≤0.005%, Cr: ≤0.02%, Ni: ≤0.02%, Cu: ≤0.02%, Al: ≤0.020%, Ti: ≤0.01%.