An electroslag remelting method for reducing silicon burn loss

Abstract

The invention discloses an electroslag remelting method for reducing silicon loss. The silicon content of the consumable electrode is controlled at the upper-middle limit of the target composition of the electroslag ingot. Coating operation is carried out on the surface-treated consumable electrode. The coating, from the inside out, is successively: an aluminum powder layer and / or a silicon oxide powder layer, and a corundum powder layer. During the electroslag remelting stage, electroslag material is added into the mold, and the average thickness of the slag pool is controlled to be 1 / 3 - 1 / 2 of the equivalent diameter of the melted consumable electrode. Meanwhile, an inert gas is blown into the mold, and its flow rate is controlled at 5 - 20 L / min. During the feeding stage: electroslag material is added into the mold again to control the thickness of the slag pool to be 1 / 2 - 1.0 of the equivalent diameter of the melted consumable electrode, and the inert gas flow rate is controlled at 10 - 30 L / min. By spraying and treating the surface of the consumable electrode, the invention effectively prevents the secondary oxidation of silicon elements in the consumable electrode during the electroslag remelting process, and while reducing silicon loss, solves the problem of poor control stability of the burning loss rate of the easily oxidized element silicon.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroslag metallurgical smelting, and particularly relates to an electroslag remelting method for reducing silicon loss. Background Art

[0002] Electroslag remelting is a special smelting method that uses the resistance heat generated when an electric current passes through molten slag as a heat source. It has unique advantages in the production of high-end quality steels (such as steels for nuclear power). With its excellent metallurgical reaction conditions and unique solidification and crystallization processes, it can effectively remove harmful inclusions in metals and improve the solidification quality of metals. However, the electroslag remelting process is generally carried out under the atmosphere. In terms of the silicon content in steel, since this element is easily oxidized, it is difficult to reduce its loss rate and achieve precise control of its content during the electroslag remelting process.

[0003] Currently, the control methods for the content of easily oxidized elements during the electroslag remelting process are as follows:

[0004] 1. Pre-action method: According to the requirements of the finished product silicon content, the silicon content of the consumable electrode is pre-controlled above the upper limit of the composition limit, controlled according to 10% - 20% above the upper limit of the over-composition requirement. The loss ratio during the electroslag remelting process is prefabricated into the consumable electrode to control the silicon loss during the electroslag remelting process and ensure the composition requirements of the electroslag ingot. However, during the electroslag remelting process, the silicon loss ratio fluctuates greatly, so it is difficult to control the prefabrication ratio of the silicon content of the consumable electrode.

[0005] 2. Online adjustment method: According to the requirements of the finished product silicon content, combined with the empirical value of the loss ratio of the easily oxidized element silicon during the electroslag furnace remelting process, the online control of the silicon content in the molten steel during the electroslag remelting process is carried out by adding ferrosilicon. However, due to different equipment states, the empirical value of the loss ratio of silicon element fluctuates greatly, and moreover, when adding ferrosilicon, it must pass through the molten slag, and the recovery rate of its silicon fluctuates greatly. Therefore, the stability of controlling the loss of the easily oxidized element silicon by this method is poor.

[0006] In summary, the above two methods both ensure that the loss ratio is controllable by increasing the silicon content. However, due to different equipment states, the loss ratio value of the silicon element fluctuates greatly. At the same time, when adding ferrosilicon, the recovery rate of silicon fluctuates greatly. Therefore, the existing technology has poor stability in controlling the loss rate of the easily oxidized element silicon. Summary of the Invention

[0007] The purpose of the present invention is to provide an electroslag remelting method for reducing silicon loss, which solves the problem of poor stability in controlling the loss rate of the easily oxidized element silicon while reducing silicon loss.

[0008] To solve the above problems, an electroslag remelting method for reducing silicon loss of the present invention includes the following content:

[0009] (1) Consumable electrode composition: In order to offset the loss of part of silicon during electroslag remelting, the silicon content of the consumable electrode is controlled at the middle to upper limit of the target composition of the electroslag ingot. The middle to upper limit refers to the range from the middle value to the upper limit value of the target composition range.

[0010] (2) Consumable electrode coating: Coating operation is carried out on the surface-treated consumable electrode. Since the loss of silicon is mainly caused by the combination of silicon in the consumable electrode with oxygen in the slag and the atmosphere, in order to reduce the loss caused by the combination of oxygen and silicon, aluminum powder can be used to combine the oxygen in the system. In addition, the progress of the loss reaction can also be inhibited by increasing the content of silicon oxide, which is the product of the silicon loss reaction in the system. Finally, in order to improve the high-temperature strength of the coating, corundum powder is coated on its outer side. Thus, the coating structure is determined, that is, the coating from the inside to the outside is in turn: aluminum powder layer and / or silicon oxide powder layer, corundum powder layer.

[0011] (3) Electroslag remelting: During the electroslag remelting process, the average thickness of the slag pool has an important influence on the production cost and quality of the electroslag ingot. The larger the equivalent diameter of the consumable electrode, the relatively larger amount of molten steel melted per unit time, and the slag pool thickness should be appropriately larger. Add electroslag materials into the mold to control the average thickness of the slag pool at 1 / 3 - 1 / 2 of the equivalent diameter of the consumable electrode being melted. At the same time, blow inert gas into the mold to control the atmosphere in the mold, and its flow rate is controlled at 5 - 20 L / min.

[0012] (4) Feeding stage: During the feeding stage, since the liquid metal is closer to the top of the mold, it is easier to absorb oxygen in the environment. To prevent the entry of oxygen in the environment, add electroslag materials into the mold again to control the thickness of the slag pool at 1 / 2 - 1.0 of the equivalent diameter of the consumable electrode being melted, and the flow rate of the inert gas is controlled at 10 - 30 L / min.

[0013] Furthermore, the surface roughness Ra of the consumable electrode reaches 0.5 - 2.0 mm so that the reducing agent coated on the surface of the consumable electrode in the subsequent process has better adhesion.

[0014] Furthermore, the thickness of the aluminum powder layer is 1.0 - 4.0 mm; the thickness of the silicon oxide powder layer is 0.5 - 1.0 mm; the thickness of the corundum powder layer is 0.5 - 1.0 mm.

[0015] Furthermore, the weight percentage of Al content in the aluminum powder raw material for the aluminum powder layer ≥ 99%, and the particle size is 200 - 300 mesh; the weight percentage of SiO2 content in the silicon oxide powder raw material for the silicon oxide powder layer ≥ 98%, and the particle size is 100 - 150 mesh; the weight percentage of Al2O3 content in the corundum powder raw material for the corundum powder layer ≥ 95%, and the particle size is 100 - 300 mesh.

[0016] Further, the thickness of the aluminum powder coating is controlled according to the oxygen content in the consumable electrode. When the oxygen content in the consumable electrode is less than or equal to 10 ppm, the coating thickness is 1.0 - 2.0 mm, including 2.0 mm. When the oxygen content in the consumable electrode is greater than 10 ppm, the coating thickness is 2.0 - 4.0 mm, not including 2.0 mm.

[0017] Further, the surface of the consumable electrode is treated with frosting, and each coating is sprayed by an electrostatic powder spraying process.

[0018] Further, the weight percentages of the electro-slag material components are as follows: CaF2 65% - 75%, Al2O3 20% - 30%, SiO2 1% - 5%, and MgO 2% - 8%.

[0019] Further, the electro-slag material is a pre-melted slag, which is baked at 600 - 800 °C for 5 - 8 hours before use.

[0020] Further, the particle size of the electro-slag material is 0.5 - 1.5 mm.

[0021] Further, the inert gas is argon.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. By controlling the composition of the consumable electrode and the surface spraying treatment before electroslag remelting production, the present invention can effectively prevent the oxidation and burning loss of silicon elements in the consumable electrode during the electroslag remelting process. Its process method is simple, safe and reliable.

[0024] 2. The aluminum powder of the coating of the present invention can effectively remove oxygen in the consumable electrode, realize the whole-process inhibition of molten steel oxygen increase during electroslag remelting, and thus realize the whole-process protection of easily oxidized silicon elements in the molten steel.

[0025] 3. The coating of the present invention contains silica powder, which can adjust the activity of SiO2 in the slag solution and further inhibit the burning loss of silicon elements in the consumable electrode.

[0026] 4. The coating of the present invention contains corundum powder, which can effectively block the contact between the consumable electrode and air, prevent the secondary oxidation of the consumable electrode in contact with air before melting, realize the whole-process protection of the consumable electrode during the whole process of electroslag remelting, and the silicon burning loss rate is reduced by more than 65% compared with the conventional control method. Detailed implementation manners

[0027] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention may be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] The present invention adopts the technology of preventing silicon burning loss on the surface of the consumable electrode. At the same time, with the conventional atmosphere protection and deoxidation process, it realizes the comprehensive, efficient and stable reduction of titanium burning loss in the electroslag remelting production process. The specific scheme is as follows:

[0029] (1) Consumable electrode composition: In order to offset the burning loss of part of the silicon during the electroslag remelting process, the silicon content in the consumable electrode is controlled at the upper limit of the finished product composition.

[0030] (2) Consumable electrode coating: ① Use treatment methods such as shot blasting, peening, and sandblasting to treat the oil stains, mill scale, etc. remaining on the surface of the consumable electrode. The treatment time is 30 - 60 minutes. In order to facilitate the spraying effect of the coating on the surface of the consumable electrode subsequently, its surface needs to be sanded to make the surface roughness reach 0.5 - 2.0 mm; ② Carry out coating operations on the consumable electrode after surface treatment. The coating is, from the inside out: an aluminum powder layer and / or a silicon oxide powder layer, and a corundum powder layer. The weight percentage of Al in the aluminum powder raw material for the aluminum powder layer ≥ 99%, the particle size is 200 - 300 mesh, and the coating thickness is 1.0 - 4.0 mm. This coating thickness is controlled according to the oxygen content in the consumable electrode. When the oxygen content in the consumable electrode is less than or equal to 10 ppm, its coating thickness is controlled at the lower limit, and the coating thickness is 1.0 - 2.0 mm, including 2.0 mm; when the oxygen content in the consumable electrode is greater than 10 ppm, its coating thickness is controlled at the upper limit, and the coating thickness is 2.0 - 4.0 mm, not including 2.0 mm. The weight percentage of SiO2 in the silicon oxide powder raw material for the silicon oxide powder layer ≥ 98%, the particle size is 100 - 150 mesh, and its coating thickness is 0.5 - 1.0 mm; the weight percentage of Al2O3 in the corundum powder raw material for the corundum powder layer ≥ 95%, the particle size is 100 - 300 mesh, and its coating thickness is 0.5 - 1.0 mm. Each layer is sprayed by electrostatic powder spraying process.

[0031] (3) Electro-slag remelting: ① The weight percentages of the components in the electro-slag charge are as follows: CaF₂ 65% - 75%, Al₂O₃ 20% - 30%, SiO₂ 1% - 5%, and MgO 2% - 8%. The slag material is pre-melted slag, which is baked at 600 - 800 °C for 5 - 8 hours before use, and the particle size of the slag material is controlled at 0.5 - 1.5 mm. ② During the electro-slag remelting process, the average thickness of the slag pool is controlled at 1 / 3 - 1 / 2 of the equivalent diameter of the consumable electrode being melted. Meanwhile, an inert gas is blown into the mold to control the atmosphere in the mold, and the flow rate is controlled at 5 - 20 L / min.

[0032] (4) Feeding stage: During the feeding stage, electro-slag charge is added into the mold again to control the thickness of the slag pool at 1 / 2 - 1.0 of the equivalent diameter of the consumable electrode being melted, and the flow rate of the inert gas is controlled at 10 - 30 L / min.

[0033] To further describe the present invention, the present invention will be described in more detail below in conjunction with embodiments:

[0034] In a certain iron and steel enterprise, an electro-slag furnace was used to conduct production tests on 60 furnaces of silicon-containing test steel for silicon-containing steel grades: 40 furnaces were completed using the conventional process, and 20 furnaces were completed using the present invention. The electrode preparation plan and production test results are as follows:

[0035] Comparative example: (conventional process)

[0036] An electro-slag remelting test for reducing silicon element loss was carried out using the conventional process. The silicon content range of the finished electro-slag ingot was 0.40% - 0.55%. The silicon content in the consumable electrode was controlled at the upper limit of the finished product requirement, 0.55%. Treatment methods such as shot blasting, peening, and sandblasting were used to treat the oil stains, scale, etc. remaining on the surface of the consumable electrode: the treatment time was 30 min; the average surface roughness was 80 μm, and other operations were carried out according to the conventional process.

[0037] Test results: Among the 40 furnaces of electro-slag ingots, the average silicon content in the electro-slag ingots was 0.45%. Among them, 3 furnaces were below the lower limit of the finished product and were rejected. The loss rate = (silicon content in the consumable electrode - silicon content in the electro-slag ingot) / silicon content in the consumable electrode × 100% = (0.55% - 0.45%) / 0.55% × 100% = 18.2%, and the component qualification rate = (number of production furnaces - number of unqualified furnaces) / number of production furnaces × 100% = (40 - 3) / 40 × 100% = 92.5%.

[0038] Example 1:

[0039] (1) Consumable electrode composition: Using the process of the present invention, the silicon content in the consumable electrode is controlled at the upper limit in the finished product, with an average control of 0.47%. (2) Consumable electrode coating: ① The surface of the consumable electrode is cleaned by sandblasting for 40 minutes, and then its surface is frosted to make the surface roughness reach 1.0 mm; ② Electrostatic powder spraying coating operation is carried out on the surface-treated consumable electrode. The coating consists of an aluminum powder layer, a silicon oxide powder layer, and a corundum powder layer from the inside out. Among them: Aluminum powder layer, the weight percentage of Al content in the aluminum powder raw material ≥ 99%, the particle size is 260 - 290 mesh, the oxygen content of the consumable electrode is 8 ppm, and the coating thickness is controlled at 1.2 mm; Silicon oxide powder layer, the weight percentage of SiO2 content in the silicon oxide powder raw material ≥ 98%, the particle size is 110 - 130 mesh, and the coating thickness is 0.6 mm; Corundum powder layer, the weight percentage of Al2O3 content in the corundum powder raw material ≥ 95%, the particle size is 140 - 160 mesh, and the coating thickness is 0.6 mm. (3) Electroslag remelting: ① The pre-melted electroslag charge is baked at 650 °C for 7 hours. The weight percentage of the electroslag charge components used is: CaF2 70%, Al2O3 25%, SiO2 1.5%, MgO 3.5%, and the particle size of the slag charge is 0.5 - 1.5 mm; ② During the electroslag remelting process, the average thickness of the slag pool is controlled at 1 / 3 of the equivalent diameter of the consumable electrode being melted, and the blowing flow rate of inert gas argon in the mold is controlled at 10 L / min. (4) Feeding stage: Electroslag charge is added into the mold again to control the thickness of the slag pool at 1 / 2 of the equivalent diameter of the consumable electrode being melted, and the flow rate of inert gas argon is controlled at 15 L / min.

[0040] Test results: Among the 5 electroslag ingots, the average silicon content in the electroslag ingots remained at 0.45%. The burning loss rate = (silicon content in the consumable electrode - silicon content in the electroslag ingot) / silicon content in the consumable electrode × 100% = (0.47% - 0.45%) / 0.47% × 100% = 4.2%. The silicon burning loss rate can be reduced compared with the conventional control method

[0041] ((Silicon burning loss rate of the conventional method - silicon burning loss rate of this method) / silicon burning loss rate of the conventional method × 100% = (18.2% - 4.2%) / 18.2% × 100% = 76.9%. All batches are qualified, and the qualification rate (stability) is 100%.

[0042] Example 2:

[0043] (1) Consumable electrode composition: Using the process of the present invention, the silicon content in the consumable electrode is controlled at the upper limit in the finished product, with an average control of 0.49%. (2) Consumable electrode coating: ① The surface of the consumable electrode is cleaned by sandblasting for 50 minutes, and then its surface is sanded to make the surface roughness reach 1.5 mm; ② Electrostatic powder spraying coating operation is carried out on the surface-treated consumable electrode. The coating is, from the inside out: an aluminum powder layer, a silicon oxide powder layer, and a corundum powder layer. Among them: for the aluminum powder layer, the weight percentage of Al content in the aluminum powder raw material ≥ 99%, the particle size is 200 - 220 mesh, the oxygen content of the consumable electrode is 25 ppm, and the coating thickness is controlled at 3.2 mm; for the silicon oxide powder layer, the weight percentage of SiO2 content in the silicon oxide powder raw material ≥ 98%, the particle size is 120 - 140 mesh, and the coating thickness is controlled at 0.8 mm; for the corundum powder layer, the weight percentage of Al2O3 content in the corundum powder raw material ≥ 95%, the particle size is 140 - 160 mesh, and the coating thickness is 0.6 mm. (3) Electroslag remelting: ① The pre-melted electroslag material is baked at 800 °C for 7 hours. The weight percentage of the electroslag material used is: CaF2 68%, Al2O3 22%, SiO2 3%, MgO 7%, and the particle size of the slag material is 0.5 - 1.5 mm; ② During the electroslag remelting process, the average thickness of the slag pool is controlled at 1 / 3 of the equivalent diameter of the consumable electrode being melted, and the blowing flow rate of the inert gas argon in the mold is controlled at 12 L / min. (4) Feeding stage: Electroslag material is added into the mold again to control the thickness of the slag pool at 1 / 2 of the equivalent diameter of the consumable electrode being melted, and the flow rate of the inert gas argon is controlled at 18 L / min.

[0044] Test results: Among the 5 electroslag ingots, the average silicon content in the electroslag ingots is maintained at 0.46%. Its burning loss rate = (silicon content in the consumable electrode - silicon content in the electroslag ingot) / silicon content in the consumable electrode × 100% = (0.49% - 0.46%) / 0.49% × 100% = 6.1%. The silicon burning loss rate can be reduced compared with the conventional control method

[0045] (Burning loss rate of the conventional method - burning loss rate of this method) / burning loss rate of the conventional method × 100% = (18.2% - 6.1%) / 18.2% × 100% = 66.5%. All batches are qualified, and the qualification rate (stability) is 100%.

[0046] Example 3:

[0047] (1) Consumable electrode composition: Using the process of the present invention, the silicon content in the consumable electrode is controlled at the upper limit in the finished product, with an average control of 0.48%. (2) Consumable electrode coating: ① The surface of the consumable electrode is cleaned by sandblasting for 50 minutes, and then its surface is subjected to frosting treatment to make the surface roughness reach 1.0 mm; ② Electrostatic powder spraying coating operation is carried out on the surface-treated consumable electrode. The coating is, from the inside out: an aluminum powder layer and a corundum powder layer. Among them: for the aluminum powder layer, the weight percentage of Al content in the aluminum powder raw material ≥ 99%, the particle size is 260 - 290 mesh, the oxygen content of the consumable electrode is 8 ppm, and the coating thickness is controlled at 1.2 mm; for the corundum powder layer, the weight percentage of Al2O3 content in the corundum powder raw material ≥ 95%, the particle size is 140 - 160 mesh, and the coating thickness is 0.6 mm. (3) Electroslag remelting: ① The pre-melted electroslag charge is baked at 650 °C for 7 hours. The weight percentage of the electroslag charge components used is: CaF2 72%, Al2O3 22%, SiO2 2.5%, MgO 3.5%, and the particle size of the slag charge is 0.5 - 1.5 mm; ② During the electroslag remelting process, the average thickness of the slag pool is controlled at 2 / 5 of the equivalent diameter of the consumable electrode being melted, and the blowing flow rate of inert gas argon in the mold is controlled at 15 L / min. (4) Feeding stage: Electroslag charge is added into the mold again to control the thickness of the slag pool at 3 / 5 of the equivalent diameter of the consumable electrode being melted, and the inert gas argon flow rate is controlled at 20 L / min.

[0048] Test results: Among the 5 electroslag ingots, the average silicon content in the electroslag ingots remains at 0.45%. Its burning loss rate = (silicon content in the consumable electrode - silicon content in the electroslag ingot) / silicon content in the consumable electrode × 100% = (0.48% - 0.45%) / 0.48% × 100% = 6.2%. The silicon burning loss rate can be reduced compared with the conventional control method

[0049] (burning loss rate of the conventional method - burning loss rate of this method) / burning loss rate of the conventional method × 100% = (18.2% - 6.2%) / 18.2% × 100% = 65.9%. All batches are qualified, and the qualification rate (stability) is 100%.

[0050] Example 4:

[0051] (1) Consumable electrode composition: Using the process of the present invention, the silicon content in the consumable electrode is controlled at the upper limit in the finished product, with an average control of 0.50%. (2) Consumable electrode coating: ① The surface of the consumable electrode is cleaned by sandblasting for 50 minutes, and then its surface is subjected to abrasive treatment to make the surface roughness reach 1.6 mm; ② Electrostatic powder spraying coating operation is carried out on the consumable electrode after surface treatment. The coating consists of, from the inside out: silicon oxide powder layer, corundum powder layer. Among them: for the silicon oxide powder layer, the weight percentage of SiO2 content in the silicon oxide powder raw material ≥ 98%, the particle size is 120 - 140 mesh, and the coating thickness is 0.8 mm; for the corundum powder layer, the weight percentage of Al2O3 content in the corundum powder raw material ≥ 95%, the particle size is 130 - 150 mesh, and the coating thickness is 0.7 mm. (3) Electroslag remelting: ① The pre-melted electroslag charge is baked at 680 °C for 6 hours. The weight percentage of the electroslag charge composition used is: CaF2 68%, Al2O3 22%, SiO2 3.5%, MgO 6.5%, and the slag charge particle size is 0.5 - 1.5 mm; ② During the electroslag remelting process, the average thickness of the slag pool is controlled at 1 / 3 of the equivalent diameter of the consumable electrode being melted, and the blowing flow rate of inert gas argon in the mold is controlled at 12 L / min. (4) Feeding stage: Electroslag charge is added into the mold again to control the thickness of the slag pool at 2 / 3 of the equivalent diameter of the consumable electrode being melted, and the inert gas argon flow rate is controlled at 25 L / min.

[0052] Test results: Among the 5 furnace electroslag ingots, the average silicon content in the electroslag ingots remained at 0.47%. Its burning loss rate = (silicon content in the consumable electrode - silicon content in the electroslag ingot) / silicon content in the consumable electrode × 100% = (0.50% - 0.47%) / 0.50% × 100% = 6%. The silicon burning loss rate can be reduced compared with the conventional control method

[0053] (Conventional method silicon burning loss rate - this method silicon burning loss rate) / conventional method silicon burning loss rate × 100% = (18.2% - 6%) / 18.2% × 100% = 69.2%. All furnace batches are qualified, and the qualification rate (stability) is 100%.

[0054] It can be seen from the above production test results that when using the present invention for electroslag remelting production test of silicon-containing steel grades, through the improvement of processes such as consumable electrode composition, slag charge composition, and electrode surface treatment, it is possible to achieve the control of low silicon burning loss during the electroslag melting process of silicon-containing steel grades, ensuring the qualification rate (stability) of the composition of silicon-containing steel grades.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electroslag remelting method for reducing silicon burn-off, characterized in that, It includes the following contents: (1) Consumable electrode composition: The silicon content of the consumable electrode is controlled at the upper-middle limit of the target composition of the electroslag ingot. (2) Consumable electrode coating: Coating operation is carried out on the consumable electrode after surface treatment. The coating consists of, from the inside out: an aluminum powder layer and / or a silicon oxide powder layer, and a corundum powder layer. (3) Electroslag remelting: Add electroslag material into the mold. The average thickness of the slag pool is controlled at 1 / 3 - 1 / 2 of the equivalent diameter of the consumable electrode being smelted. At the same time, an inert gas is blown into the mold, and its flow rate is controlled at 5 - 20 L / min. The weight percentage of the components of the electroslag material is: CaF2 65% - 75%, Al2O3 20% - 30%, SiO2 1% - 5%, MgO 2% - 8%. (4) Feeding stage: Add electroslag material into the mold again to control the thickness of the slag pool at 1 / 2 - 1.0 of the equivalent diameter of the consumable electrode being smelted, and the inert gas flow rate is controlled at 10 - 30 L / min.

2. The electroslag remelting method for reducing silicon loss according to claim 1, characterized in that, The surface roughness Ra of the consumable electrode reaches 0.5 - 2.0 mm.

3. The electroslag remelting method for reducing silicon loss according to claim 1, characterized in that, The thickness of the aluminum powder layer is 1.0 - 4.0 mm; the thickness of the silicon oxide powder layer is 0.5 - 1.0 mm; the thickness of the corundum powder layer is 0.5 - 1.0 mm.

4. A electroslag remelting method for reducing silicon loss according to claim 1 or 3, characterized in that, The weight percentage of Al content in the aluminum powder raw material for the aluminum powder layer ≥ 99%, and the particle size is 200 - 300 mesh; the weight percentage of SiO2 content in the silicon oxide powder raw material for the silicon oxide powder layer ≥ 98%, and the particle size is 100 - 150 mesh; the weight percentage of Al2O3 content in the corundum powder raw material for the corundum powder layer ≥ 95%, and the particle size is 100 - 300 mesh.

5. The electroslag remelting method for reducing silicon loss according to claim 1 or 3, characterized in that, The thickness of the aluminum powder coating is controlled according to the oxygen content in the consumable electrode. When the oxygen content in the consumable electrode is less than or equal to 10 ppm, its coating thickness is 1.0 - 2.0 mm, including 2.0 mm. When the oxygen content in the consumable electrode is greater than 10 ppm, its coating thickness is 2.0 - 4.0 mm, not including 2.0 mm.

6. The electroslag remelting method for reducing silicon loss according to claim 1 or 3, characterized in that, The surface of the consumable electrode is treated by sandblasting, and each coating is sprayed by electrostatic powder spraying process.

7. An electroslag remelting method for reducing silicon burn-off according to claim 1, characterized in that The electroslag material is pre-melted slag, and it is baked at 600 - 800 °C for 5 - 8 hours before use.

8. A electroslag remelting method for reducing silicon burn loss according to claim 1, characterized in that, The particle size of the electroslag material is 0.5 - 1.5 mm.

9. A electroslag remelting method for reducing silicon burn loss according to claim 1, characterized in that, The inert gas is argon.