A ternary slag system for electroslag remelted steel production and method of use thereof

Abstract

The present application relates to the technical field of electroslag remelting smelting, and particularly relates to a ternary slag system for electroslag remelting steel production and a use method thereof, the ternary slag system comprises the following components in percentage by weight: CaF2 47% to 53%, CaO 23% to 27%, Al2O3 23% to 27%, and the rest is impurities, wherein TiO2 in the impurities is less than or equal to 0.1%, C is less than or equal to 0.05%, SiO2 is less than or equal to 0.3%, and H2O is less than or equal to 0.50%. The present application designs a new ternary slag system formula by increasing the content of CaO and Al2O3 in the slag system, smelts the titanium-containing steel with a Ti content in the range of 1% to 3% by using the new ternary slag system formula, and can improve the surface quality of the electroslag ingot formed after electroslag remelting, the electroslag ingot surface is free of heavy skin, the ingot yield is improved, the cracking problem in the steel ingot forging process is solved, and the comprehensive yield is improved.

Description

Technical Field

[0001] This invention relates to the field of electroslag remelting technology, and in particular to a ternary slag system for the production of electroslag remelted steel grades and its application method. Background Technology

[0002] For high-pressure air coolers in highly corrosive gas fields and hydrogenation units, corrosion-resistant high-temperature alloys are currently the primary corrosion-resistant materials.

[0003] The corrosion-resistant material mainly uses UNS N08825 alloy. UNS N08825 alloy has strong corrosion resistance, which can not only overcome the corrosion problem of pipelines in harsh environments, but also simplify the ground process and ensure that the equipment can operate stably for a long period of time.

[0004] Electroslag remelting is a process for remelting and refining steel produced by electric furnaces and converters. The process involves placing pre-melted slag in a copper water-cooled crystallizer, inserting one end of a consumable electrode into a slag pool, and forming a circuit between the consumable electrode, slag pool, molten metal pool, ingot, and bottom water tank through a short network cable and a transformer. The slag pool is heated to a high temperature by its own resistance, and the end of the consumable electrode is heated and melted by the molten slag to form molten metal droplets. The molten metal droplets then fall off, pass through the slag pool, and enter the molten metal pool. Due to the forced cooling effect of the water-cooled crystallizer, the liquid metal quickly solidifies to form an ingot. The ingot solidifies sequentially from bottom to top to form an electroslag ingot.

[0005] The Ti content of UNS N08825 alloy electrode rods is approximately 1.2%. In existing technologies, UNS N08825 alloy uses a ternary pre-melted slag (CaF2:Al2O3:CaO = 70%:15%:15%). To reduce Ti loss during electroslag remelting, the industry adds 2%-3% TiO2 powder to the slag system. However, adding TiO2 increases the viscosity of the slag, reduces slag pool fluidity, and makes it difficult to guarantee the surface quality of the steel ingot. This results in an uneven surface and slag grooves on the prepared electroslag ingot. Figure 1 As shown in the figure, electroslag ingots need to be peeled before being transferred to the next process. The amount of peeling is between 3% and 7%, which can easily cause surface cracking during the forging process. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, the present invention aims to provide a ternary slag system for the production of electroslag remelted steel and its application method. This invention designs a new ternary slag system formula by increasing the CaO and Al2O3 content in the slag system. Using this new ternary slag system formula to smelt titanium-containing steel with a Ti content in the range of 1%-3% can improve the surface quality of the electroslag ingots formed after electroslag remelting, resulting in an ingot surface free of scale, increased ingot yield, and resolution of cracking issues during steel ingot forging, thereby improving the overall yield.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a ternary slag system for the production of electroslag remelted steel grades, the ternary slag system comprising the following components by weight percentage: CaF2 47%~53%, CaO 23%~27%, Al2O3 23%~27%, with the remainder being impurities, of which: TiO2≤0.1%, C≤0.05%, SiO2≤0.3%, H2O≤0.50%.

[0009] This invention designs a new ternary slag system formula by increasing the content of CaO and Al2O3 in the slag system. Using this new ternary slag system formula to smelt titanium-containing steel with a Ti content in the range of 1%-3% can improve the surface quality of the electroslag ingot formed after electroslag remelting. The surface of the electroslag ingot is free of heavy scale, which increases the ingot yield and solves the problem of cracking in the steel ingot forging process, thereby improving the overall yield.

[0010] Furthermore, the mass percentage of Ti in the electroslag remelted steel ranges from 1% to 3%.

[0011] Furthermore, the electroslag remelted steel grade includes at least one of UNS N08825 and EMS200.

[0012] In a second aspect, the present invention provides a method for using a ternary slag system for the production of electroslag remelted steel grades as described in the first aspect, the method comprising the following steps:

[0013] S1. Prepare slag according to the weight percentage of each component in the ternary slag system used for the production of electroslag remelted steel grades to obtain the ternary slag system;

[0014] S2. Place the ternary slag system obtained in step S1 in a baking oven and heat it to 650-700℃ (e.g., 650℃, 680℃ or 700℃) for heat preservation. The heat preservation time is ≥6 hours (e.g., 6 hours, 8 hours, 10 hours or 12 hours). After baking, quickly transfer it for use. The transfer time is ≤10 minutes.

[0015] S3. The ternary slag system after heat preservation and baking is added to the electroslag furnace crystallizer. Argon gas is used for protection throughout the process. The consumable electrode to be remelted is electroslag remelted to obtain electroslag ingot.

[0016] Furthermore, in step S3, the amount of the ternary slag system used is 20-40 kg / t consumable electrode.

[0017] Furthermore, aluminum powder is added to the baked ternary slag system, wherein the amount of aluminum powder added is 2-5 g / kg of ternary slag system.

[0018] Furthermore, the smelting current for the electroslag remelting is 8000-14000A, and the smelting voltage is 32-78V.

[0019] Furthermore, the melting rate of the electroslag remelting is 180~720 kg / h.

[0020] Furthermore, the process of adding the ternary slag system after heat preservation and baking into the electroslag furnace crystallizer, with argon protection throughout, and the electroslag remelting of the consumable electrode to be remelted includes: under argon protection, adding the consumable electrode to be remelted into the crystallizer for arc initiation operation, and starting the electroslag remelting; the ternary slag system after heat preservation and baking is added into the electroslag furnace crystallizer in stages during the electroslag remelting process.

[0021] Furthermore, the ternary slag system after heat preservation and baking is added to the electroslag furnace crystallizer in stages during the electroslag remelting process, including: adding 20% ​​to 30% of the total weight of the ternary slag system after the arc initiation and slag formation are completed, and then adding the remaining ternary slag system at a rate of 1 to 4 kg / min during the electroslag remelting process.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0023] This invention designs a new ternary slag system formula by increasing the content of CaO and Al2O3 in the slag system. Using this new ternary slag system formula to smelt titanium-containing steel with a Ti content in the range of 1%-3% can improve the surface quality of the electroslag ingot formed after electroslag remelting. The surface of the electroslag ingot is free of heavy scale, which increases the ingot yield and solves the problem of cracking in the steel ingot forging process, thereby improving the overall yield. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 A schematic diagram of an electroslag ingot prepared using existing technology;

[0026] Figure 2 This is a graph showing the electrode smelting process in Example 1;

[0027] Figure 3 This is a schematic diagram of the electroslag ingot prepared in Example 1;

[0028] Figure 4 This is a schematic diagram of the electroslag ingot prepared in Example 1 during the forging process;

[0029] Figure 5 This is a graph showing the electrode smelting process in Example 2;

[0030] Figure 6 This is a schematic diagram of the electroslag ingot prepared in Example 2;

[0031] Figure 7 This is a schematic diagram of the electroslag ingot prepared in Example 2 during the forging process;

[0032] Figure 8 This is a graph showing the electrode smelting process in Example 3;

[0033] Figure 9 This is a schematic diagram of the electroslag ingot prepared in Example 3;

[0034] Figure 10 This is a schematic diagram of the electroslag ingot prepared in Example 3 during the forging process;

[0035] Figure 11 The diagram shows the ternary phase diagram of CaF2-Al2O3-CaO.

[0036] Icons: 1-Voltage; 2-Fusing rate; 3-Current. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0038] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0039] In a first aspect, the present invention provides a ternary slag system for the production of electroslag remelted steel grades, the ternary slag system comprising the following components by weight percentage: CaF2 47%~53%, CaO 23%~27%, Al2O3 23%~27%, with the remainder being impurities, of which: TiO2≤0.1%, C≤0.05%, SiO2≤0.3%, H2O≤0.50%.

[0040] This invention designs a new ternary slag system formula by increasing the content of CaO and Al2O3 in the slag system. Using this new ternary slag system formula to smelt titanium-containing steel with a Ti content in the range of 1%-3% can improve the surface quality of the electroslag ingot formed after electroslag remelting. The surface of the electroslag ingot is free of heavy scale, achieving zero peeling, improving the ingot yield, solving the cracking problem in the steel ingot forging process, and improving the overall yield.

[0041] The ternary slag system has a high CaO content and high alkalinity, which reacts with acidic substances to form stable compounds, promoting desulfurization and deoxidation reactions, thereby reducing the oxidation loss of Ti elements. The Ti composition is stably controlled during the electroslag remelting process, the surface quality of the electroslag ingot is better, the electroslag ingot does not peel off, and the overall yield is improved.

[0042] Depend on Figure 11 It can be seen that in the CaF2-Al2O3-CaO ternary slag system, CaF2 and C 12 The liquidus temperature near the A7 (12CaO·7Al2O3) line is relatively low, and the liquidus temperature is even lower closer to the CaF2 direction. The ternary slag system provided by this invention has a lower melting point and lower viscosity, which can improve fluidity and solve the surface problems of electroslag ingots.

[0043] In the aforementioned ternary slag system for producing electroslag remelted steel, as an optional implementation, the mass percentage content of Ti in the electroslag remelted steel ranges from 1% to 3%.

[0044] In the above-mentioned ternary slag system for the production of electroslag remelted steel grades, as an optional embodiment, the electroslag remelted steel grade includes at least one of UNS N08825 and EMS200.

[0045] In a second aspect, the present invention provides a method for using a ternary slag system for the production of electroslag remelted steel grades as described in the first aspect, the method comprising the following steps:

[0046] S1. Prepare slag according to the weight percentage of each component in the ternary slag system used for the production of electroslag remelted steel grades to obtain the ternary slag system;

[0047] S2. Place the ternary slag system obtained in step S1 in a baking oven and heat it to 650-700℃ (e.g., 650℃, 680℃ or 700℃) for heat preservation. The heat preservation time is ≥6 hours (e.g., 6 hours, 8 hours, 10 hours or 12 hours). After baking, quickly transfer it for use. The transfer time is ≤10 minutes.

[0048] S3. The ternary slag system after heat preservation and baking is added to the electroslag furnace crystallizer. Argon gas is used for protection throughout the process. The consumable electrode to be remelted is electroslag remelted to obtain electroslag ingot.

[0049] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel, as an optional implementation, in step S3, the amount of the ternary slag system used is 20-40 kg / t consumable electrode (for example, it can be 20 kg / t consumable electrode, 30 kg / t consumable electrode, or 40 kg / t consumable electrode).

[0050] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel grades, as an optional implementation, aluminum powder is added to the baked ternary slag system, and the amount of aluminum powder added is 2-5 g / kg of ternary slag system (for example, it can be 2 g / kg ternary slag system, 3 g / kg ternary slag system, or 5 g / kg ternary slag system).

[0051] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel grades, as an optional implementation, the smelting current of the electroslag remelting is 8000-14000A (for example, it can be 8000A, 10000A, 12000A, 14000A), and the smelting voltage is 32-78V (for example, it can be 32V, 40V, 50V, 60V, 78V).

[0052] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel grades, as an optional implementation, the electroslag remelting melting rate is 180~720 kg / h, for example, it can be 180 kg / h, 200 kg / h, 400 kg / h, 600 kg / h or 720 kg / h.

[0053] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel, as an optional implementation, the step of adding the heat-preserving and baking ternary slag system into the electroslag furnace crystallizer, with argon protection throughout the process, and performing electroslag remelting of the consumable electrode to be remelted includes: under argon protection, adding the consumable electrode to be remelted into the crystallizer for arc initiation operation, starting the electroslag remelting, and adding the heat-preserving and baking ternary slag system into the electroslag furnace crystallizer in stages during the electroslag remelting process.

[0054] In the above-mentioned method of using the ternary slag system for the production of electroslag remelted steel grades, as an optional implementation, the ternary slag system after heat preservation and baking is added to the electroslag furnace crystallizer in stages during the electroslag remelting process, including: adding 20% ​​to 30% of the total weight of the ternary slag system after the arc initiation and slag formation are completed, and then adding the remaining ternary slag system at a rate of 1 to 4 kg / min during the electroslag remelting process.

[0055] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0056] In the following embodiments and comparative examples:

[0057] Forging yield = qualified weight of finished product / amount of raw materials fed.

[0058] Example 1

[0059] The ternary slag system provided in this embodiment for the production of electroslag remelted steel grades includes the following components by weight percentage: CaF2 49.88%, CaO 25.70%, Al2O3 24.02%, with the remainder being impurities, including: TiO2 0.01%, C 0.02%, SiO2 0.22%, and H2O 0.15%.

[0060] UNS N08825 alloy was smelted in a 5-ton ingot-shaped (φ660mm in diameter) electroslag remelting furnace.

[0061] The consumable electrode rod weighs 5t and has a diameter of φ500. The composition of the consumable electrode rod by weight percentage includes: C 0.010%, Cr 22.25%, Ni 39.75%, Cu 2.05%, Mo 3.02%, Al 0.087%, Ti 1.18%, with the balance being iron and unavoidable impurities.

[0062] The method for using the ternary slag system in the production of electroslag remelted steel provided in this embodiment includes the following steps:

[0063] S1. The ternary slag system is prepared by mixing the slag according to the weight percentage of each component in the ternary slag system for producing electroslag remelted steel provided in this embodiment.

[0064] S2. Place the ternary slag system obtained in step S1 in a baking oven, heat it to 650℃ and keep it warm for 6 hours. After baking, quickly transfer it for use, with a transfer time of 8 minutes.

[0065] S3. Add 400g of aluminum powder to 150kg of preheated ternary slag system for electroslag remelting in this step. Under argon protection, lower the consumable electrode rod into a 660mm diameter crystallizer for arc ignition. Two minutes after arc ignition, add 30wt% of the preheated ternary slag system (containing aluminum powder) to the crystallizer using a feeder, followed by the remaining preheated ternary slag system (containing aluminum powder). The ternary slag system addition time is 35 minutes. After arc ignition and slag formation, adjust the remelting voltage to approximately 42V and the current to approximately 12000A. The slag pool is heated to a high temperature by its own resistance. The end of the consumable electrode rod is heated and melted by the molten slag, forming metal droplets. These droplets then fall off and pass through the slag pool into the molten metal pool. Due to the forced cooling effect of the water-cooled crystallizer, the liquid metal rapidly solidifies to form an ingot. The ingot solidifies sequentially from bottom to top, resulting in an electroslag ingot with a diameter of 660mm. The normal remelting rate is 600kg / h.

[0066] Figure 2This is the electrode smelting curve diagram of this embodiment, from Figure 2 It can be seen that the 5.0t ingot-shaped UNSN08825 alloy produced in this embodiment has a stable melting rate curve, small melting rate fluctuation, and stable control during the smelting process. Figure 3 This is a schematic diagram of the electroslag ingot prepared in this embodiment. Figure 3 It can be seen that the surface of the electroslag ingot is good, without heavy scale and slag groove defects, achieving zero peeling. Figure 4 This is a schematic diagram of the electroslag ingot prepared in this embodiment during the forging process. Figure 4 As can be seen, no surface cracks occurred during forging. The forging yield of the electroslag ingot prepared in this embodiment was 79.21%, which is 3.36% higher than that of Comparative Example 1.

[0067] The head and tail components of the electroslag ingot prepared in this embodiment were tested, and the results are shown in Table 1. As can be seen from Table 1, the head and tail components passed the test.

[0068] Table 1

[0069]

[0070] Comparative Example 1

[0071] This comparative example uses quaternary premelted slag. 2 wt% TiO2 powder is added to ternary premelted slag (CaF2:Al2O3:CaO = 70wt%:15wt%:15wt%) to obtain quaternary premelted slag.

[0072] UNS N08825 alloy was smelted in a 5-ton ingot-shaped (φ660mm in diameter) electroslag remelting furnace.

[0073] The consumable electrode rod weighs 5t and has a diameter of φ500. The composition of the consumable electrode rod by weight percentage includes: C 0.010%, Cr 22.25%, Ni 39.75%, Cu 2.05%, Mo 3.02%, Al 0.087%, Ti 1.18%, with the balance being iron and unavoidable impurities.

[0074] The quaternary premelted slag provided in this comparative example is used in accordance with the method of using the ternary slag system for producing electroslag remelted steel grades provided in Example 1.

[0075] The forging yield of the electroslag ingots produced in this comparative example is 75.85%.

[0076] Example 2

[0077] The ternary slag system provided in this embodiment for the production of electroslag remelted steel grades includes the following components by weight percentage: CaF2 47.43%, CaO 23.98%, Al2O3 23.82%, with the remainder being impurities, including: TiO2 0.01%, C 0.04%, SiO2 0.30%, and H2O 0.12%.

[0078] UNS N08825 alloy was smelted in a 10-ton ingot-shaped (φ885mm diameter) electroslag remelting furnace.

[0079] The consumable electrode rod weighs 10.6t and has a diameter of φ730mm. The composition of the consumable electrode rod by weight percentage includes: C 0.008%, Cr 22.21%, Ni 40.04%, Cu 2.06%, Mo 3.02%, Al 0.059%, Ti 1.16%, with the balance being iron and unavoidable impurities.

[0080] The method for using the ternary slag system in the production of electroslag remelted steel provided in this embodiment includes the following steps:

[0081] S1. The ternary slag system is prepared by mixing the slag according to the weight percentage of each component in the ternary slag system for producing electroslag remelted steel provided in this embodiment.

[0082] S2. Place the ternary slag system obtained in step S1 in a baking oven, heat it to 650℃ and keep it warm for 6 hours. After baking, quickly transfer it for use, with a transfer time of 10 minutes.

[0083] S3. Add 800g of aluminum powder to 330kg of baked ternary slag system for electroslag remelting in this step. Under argon protection, lower the consumable electrode rod into a crystallizer with a diameter of 885mm for arc initiation. Two minutes after arc initiation, add 30wt% of the baked ternary slag system (containing aluminum powder) to the crystallizer using a feeder, followed by the remaining baked ternary slag system (containing aluminum powder). The ternary slag system addition time is 70 minutes. After arc initiation and slag formation, adjust the remelting voltage to approximately 78V and the current to approximately 13000A. The slag pool is heated to a high temperature by its own resistance. The end of the consumable electrode rod is heated and melted by the molten slag, forming metal droplets. The metal droplets then fall off, pass through the slag pool, and enter the molten metal pool. Due to the forced cooling effect of the water-cooled crystallizer, the liquid metal rapidly solidifies to form an ingot. The ingot solidifies sequentially from bottom to top, resulting in an electroslag ingot with a diameter of 885mm. The normal remelting rate is 720kg / h.

[0084] Figure 5 This is the electrode smelting curve diagram of this embodiment, from Figure 5 It can be seen that the melting rate curve of the 10.0t ingot-shaped UNSN08825 alloy produced in this embodiment is stable during the smelting process. Figure 6This is a schematic diagram of the electroslag ingot prepared in this embodiment. Figure 6 It can be seen that the surface of the electroslag ingot is good, without heavy scale and slag groove defects, achieving zero peeling. Figure 7 This is a schematic diagram of the electroslag ingot prepared in this embodiment during the forging process. Figure 7 As can be seen, the forging process went smoothly without any surface cracks or other problems. The forging yield of the electroslag ingot prepared in this embodiment was 79.99%, which is 4.14% higher than that of Comparative Example 2. The head and tail components of the electroslag ingot prepared in this embodiment were tested, and the results are shown in Table 2. As can be seen from Table 2, the head and tail components passed the test.

[0085] Table 2

[0086]

[0087] Comparative Example 2

[0088] This comparative example uses quaternary premelted slag. 2 wt% TiO2 powder is added to ternary premelted slag (CaF2:Al2O3:CaO = 70wt%:15wt%:15wt%) to obtain quaternary premelted slag.

[0089] UNS N08825 alloy was smelted in a 10-ton ingot-shaped (φ885mm diameter) electroslag remelting furnace.

[0090] The consumable electrode rod weighs 10.6t and has a diameter of φ730mm. The composition of the consumable electrode rod by weight percentage includes: C 0.008%, Cr 22.21%, Ni 40.04%, Cu 2.06%, Mo 3.02%, Al 0.059%, Ti 1.16%, with the balance being iron and unavoidable impurities.

[0091] The quaternary premelted slag provided in this comparative example is used in accordance with the method of using the ternary slag system for producing electroslag remelted steel grades provided in Example 2.

[0092] The forging yield of the electroslag ingots produced in this comparative example is 75.85%.

[0093] Example 3

[0094] The ternary slag system provided in this embodiment for the production of electroslag remelted steel grades includes the following components by weight percentage: CaF2 48.66%, CaO 26.57%, Al2O3 24.09%, with the remainder being impurities, including: TiO2 0.04%, C 0.02%, SiO2 0.23%, and H2O 0.20%.

[0095] EMS200 alloy was smelted in a 2-ton ingot-shaped (φ435mm in diameter) electroslag remelting furnace.

[0096] The consumable electrode rod weighs 2t and has a diameter of φ300mm. The composition of the consumable electrode rod by weight percentage includes: C 0.17%, Cr 16.32%, Ni 32.33%, Nb 2.29%, Al 2.29%, Ti 2.82%, with the balance being iron and unavoidable impurities.

[0097] The method for using the ternary slag system in the production of electroslag remelted steel provided in this embodiment includes the following steps:

[0098] S1. The ternary slag system is prepared by mixing the slag according to the weight percentage of each component in the ternary slag system for producing electroslag remelted steel provided in this embodiment.

[0099] S2. Place the ternary slag system obtained in step S1 in a baking oven, heat it to 650℃ and keep it warm for 6 hours. After baking, quickly transfer it for use, with a transfer time of 7 minutes.

[0100] S3. Add 100g of aluminum powder to 45kg of baked ternary slag system for electroslag remelting in this step. Under argon protection, lower the consumable electrode rod into a 435mm diameter crystallizer for arc ignition. Two minutes after arc ignition, add 30wt% of the baked ternary slag system (containing aluminum powder) to the crystallizer using a feeder, followed by the remaining baked ternary slag system (containing aluminum powder). The ternary slag system addition time is 23 minutes. After arc ignition and slag formation, adjust the remelting voltage to approximately 45V and the current to approximately 9000A. The slag pool is heated to a high temperature by its own resistance. The end of the consumable electrode rod is heated and melted by the molten slag, forming metal droplets. These droplets then fall off and pass through the slag pool into the molten metal pool. Due to the forced cooling effect of the water-cooled crystallizer, the liquid metal rapidly solidifies to form an ingot. The ingot solidifies sequentially from bottom to top, resulting in an electroslag ingot with a diameter of 435mm. The normal remelting rate is 180kg / h.

[0101] Figure 8 This is the electrode smelting curve diagram of this embodiment, from Figure 8 It can be seen that the melting rate curve of the 2.0t ingot-shaped EMS200 alloy produced in this embodiment is stable during the smelting process. Figure 9 This is a schematic diagram of the electroslag ingot prepared in this embodiment. Figure 9 It can be seen that the surface of the electroslag ingot is good, without heavy scale and slag groove defects, achieving zero peeling. Figure 10 This is a schematic diagram of the electroslag ingot prepared in this embodiment during the forging process. Figure 10 It can be seen that no surface cracks or other problems occurred during the forging process. The composition of the head and tail of the electroslag ingot prepared in this embodiment was tested, and the results are shown in Table 3. As can be seen from Table 3, the composition of the head and tail passed the test.

[0102] Table 3

[0103]

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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. A method of using a ternary slag system for the production of electroslag remelted steel grades, characterized in that, The ternary slag system comprises the following components in percentage by weight: CaF2 47%-53%, CaO 23%-27%, Al2O3 23%-27%, and the rest is impurities, wherein TiO2≤0.1%, C≤0.05%, SiO2≤0.3%, and H2O≤0.50%; The use method comprises the following steps: S1, according to the weight percentage of each component in the ternary slag system for the production of electroslag remelted steel, the ternary slag system is prepared; S2, the ternary slag system obtained in step S1 is placed in a baking furnace, and is heated to 650-700 DEG C and is kept for ≥6 hours, and after baking, it is quickly transferred for use, and the transfer time is ≤10 min; S3, the ternary slag system after heat preservation and baking is added to the crystallizer of the electroslag furnace, and the whole process is protected by argon, and the consumable electrode to be remelted is electroslag remelted to obtain an electroslag ingot; The ternary slag system after heat preservation and baking is added to the crystallizer of the electroslag furnace, and the whole process is protected by argon, and the consumable electrode to be remelted is electroslag remelted, which comprises: under the protection of argon, the consumable electrode to be remelted is added to the crystallizer for arc starting operation, and the electroslag remelting is started, and the ternary slag system after heat preservation and baking is added to the crystallizer of the electroslag furnace in stages during the electroslag remelting process; The ternary slag system after heat preservation and baking is added to the crystallizer of the electroslag furnace in stages during the electroslag remelting process, which comprises: after the arc starting slagging is finished, 20%-30% of the total weight of the ternary slag system is added first, and then the remaining ternary slag system is added at a rate of 1-4 kg / min during the electroslag remelting process; The electroslag remelted steel is UNS N08825.

2. The method of using a ternary slag series for the production of electro- remelted steel grades according to claim 1, characterized in that, In step S3, the amount of the ternary slag system is 20-40 kg / t of the consumable electrode.

3. The method of using a ternary slag series for ESR steel production according to claim 1, characterized in that, Aluminum powder is added to the ternary slag system after baking, and the amount of the aluminum powder added is 2-5 g / kg of the ternary slag system.

4. The method of using a ternary slag series for ESR steel production according to claim 1, characterized in that, The smelting current of the electroslag remelting is 8000-14000 A, and the smelting voltage is 32-78 V.

5. The method of using a ternary slag series for the production of electro- remelted steel grades according to claim 1, characterized in that, The melting rate of the electroslag remelting is 180-720 kg / h.

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