Die casting-electroslag remelting coupling process for rare earth efficient homogeneous reinforced special steel

Abstract

The invention provides a die casting-electroslag remelting coupling process for special steel efficiently homogenized and strengthened by rare earth. The process comprises the following steps: hanging a rare earth rod in a die casting die for smelting; molten steel enters a mold from the bottom through a pouring gate, the molten steel is molten after making contact with a rare earth rod, a cast ingot is obtained after the molten steel is cooled, solidified and demolded, and the positions of a riser and a steel injection opening end are marked; forging the obtained cast ingot into a consumable electrode suitable for an electroslag remelting process; a clamping electrode is welded at the position of a steel injection opening of the consumable electrode, and electroslag remelting is prepared by taking the position of a riser as a melting tip; after the electroslag is completely melted under the action of a graphite electrode, electroslag remelting is started; in the remelting process, a reducing agent is added into a molten pool from time to time until the electrode is completely melted, the rare earth hanging adding method and the electroslag remelting technology are combined, the rare earth elements in the remelted steel ingot are evenly distributed, and therefore the action effect of the rare earth elements is enhanced, and the utilization rate of the rare earth elements is increased.

Description

Technical Field

[0001] The invention relates to the technical field of short-process electric furnace steelmaking, in particular to a die casting-electroslag remelting coupling process for rare earth high-efficiency homogeneous strengthening of special steel. Background Art

[0002] Rare earth modification can further refine grains, inhibit segregation, and refine the formation of primary carbides. At the same time, rare earths can modify inclusions in molten steel into fine spherical inclusions, reduce the impact of inclusions on the mechanical properties of steel, and improve the strength and impact toughness of steel. When rare earths are added during steelmaking by the briquetting method, the recovery rate of rare earths is low; and when rare earths are added by the hanging method during the die casting process, rare earth elements cannot be effectively diffused in the molten steel due to the poor fluidity of the molten steel and the fast solidification time. At this time, the density of rare earth inclusions formed in the molten steel is higher than that of the molten steel. Under the action of gravity, the rare earth elements in the steel ingot show an uneven distribution phenomenon of "high at the bottom and low at the top".

[0003] The electroslag remelting process uses the high temperature generated by the current passing through the high-resistance refining slag to perform secondary refining of the consumable electrode. During the smelting process, the bottom of the consumable electrode gradually melts to form metal droplets, which fall and pass through the slag layer and react with the refining slag to achieve the purpose of purifying the molten steel. Through the reaction and redistribution of the elements in the molten steel during the refining process, the macrosegregation of the steel ingot can be improved, and the rare earth elements can be evenly distributed in the molten steel. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a rare earth high-efficiency homogeneous strengthening of special steel die casting - electroslag remelting coupling process to solve the problems raised in the above-mentioned background technology. The present invention combines the rare earth hanging addition method with the electroslag remelting technology to make the rare earth elements in the remelted steel ingots evenly distributed, thereby enhancing the effect of the rare earth elements and improving their utilization rate.

[0005] In order to achieve the above object, the present invention is implemented by the following technical scheme: a rare earth high-efficiency homogeneous strengthening special steel die casting-electroslag remelting coupling process, the process comprising the following steps:

[0006] S1: Hanging a rare earth rod in a die casting mold, wherein the mass of the rare earth rod is calculated based on the mass of the molten steel poured into the mold and the element content in the rare earth rod;

[0007] S2: smelting through the electric arc furnace scrap melting-refining process;

[0008] S3: The molten steel obtained in step S2 is fed into the mold from the bottom through the pouring channel, and melted after contacting the rare earth rod. After cooling and solidification, the ingot is demoulded to obtain an ingot, and the positions of the riser and the steel injection port are marked;

[0009] S4: forging the ingot obtained in step S3 into a consumable electrode suitable for an electroslag remelting process, and taking samples at the riser and the steel pouring port to detect the rare earth content in the steel;

[0010] S5: welding a clamping electrode at the steel pouring port of the consumable electrode, and using the riser position as the melting tip to prepare for electroslag remelting;

[0011] S6: After the electroslag containing rare earth oxides is completely melted under the action of the graphite electrode, the consumable electrode prepared in step S4 is inserted into the crystallizer to start electroslag remelting;

[0012] S7: During the remelting process, reducing agent is added to the molten pool from time to time until the electrode is completely melted.

[0013] Furthermore, in step S1, the material of the object hanging the rare earth rod must not contaminate the molten steel, and the mass of the rare earth rod is calculated by the following formula:

[0014]

[0015] Among them: M1-rare earth rod mass, M2-mould steel liquid mass, ω1-rare earth content in rare earth rod, ω2-rare earth target content in steel liquid.

[0016] Furthermore, in step S2, the oxygen content in the molten steel is 30-100 ppm, the sulfur content is lower than 150 ppm, and the tapping temperature is 1500-1560°C.

[0017] Furthermore, before pouring, the entire cavity of the mold is filled with argon gas so that the mold is placed in an inert protective atmosphere to prevent secondary oxidation of the molten steel.

[0018] Furthermore, in step S4, the smelting time of electroslag remelting is adjusted according to the difference in rare earth content between the steel pouring port end and the riser end of the consumable electrode to ensure uniform distribution of rare earth elements in the electroslag ingot.

[0019] Furthermore, the total amount of refined slag is such that the thickness of the slag layer is 140 to 200 mm, and the initial composition of the refined slag is 48 to 56 wt. % CaF2 - 18 to 28 wt. % Al2O3 - 15 to 35 wt. % La2O3.

[0020] Furthermore, the target mass M of the refined slag is calculated according to the size of the target electroslag ingot. i And composition:

[0021] M i =ρ slag ·H·πr 2

[0022] Where: slag -slag density, H-slag layer thickness, r-inner diameter of crystallizer.

[0023] Furthermore, according to the target quality M of the refined slag i Calculate the mass M of the reducing agent Ca-Si alloy by the composition h :

[0024]

[0025] in: -Mass percentage of La2O3 in slag, w Ca -Mass percentage of Ca in Ca-Si alloy.

[0026] Furthermore, in step S7, the start time of adding the reducing agent is determined to be when the consumable electrode is inserted into the molten pool to start refining, and the end time of adding the reducing agent is determined to be when the electroslag remelting shrinkage compensation starts; the batch addition interval of the reducing agent is to divide this time period into 24 equal parts, and add the reducing agent batch by batch according to these intervals.

[0027] Furthermore, the steel injection port is selected as the starting tip of the electroslag remelting to perform the remelting operation; and the slag is periodically replenished at the gap between the electrode and the inner wall of the crystallizer.

[0028] Beneficial effects of the present invention:

[0029] 1. This rare earth homogenization process designed for die casting and electroslag remelting processes uses a hanging method to add rare earth elements during the molten steel die casting stage. This method significantly improves the recovery rate of rare earths, allowing them to be efficiently integrated into the molten steel system.

[0030] 2. During the implementation of the die casting-electroslag remelting coupling process of the rare earth efficient homogenization strengthened special steel, for the die casting ingot with the characteristics of "low rare earth content in the riser and high rare earth content in the steel pouring port", the steel pouring port is cleverly selected as the starting tip of the electroslag remelting for remelting operation. This measure ensures that the rare earth elements are evenly distributed inside the steel, thereby effectively improving the metallurgical quality and mechanical properties of the steel, and laying a solid foundation for the high-quality application of steel.

[0031] 3. The die casting-electroslag remelting coupling process of the rare earth high-efficiency homogenization strengthened special steel is optimized and upgraded within the framework of the original smelting process. This optimization method maintains the relative stability of production costs while ensuring the rare earth homogenization treatment effect, with only minor cost fluctuations, greatly improving the balance between production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a die casting-electroslag remelting coupling process for rare earth high-efficiency homogeneous strengthening special steel of the present invention;

[0033] Figure 2A three-dimensional schematic diagram of a casting mold used in the present invention;

[0034] Figure 3 This is a schematic diagram of consumable electrode welding of the present invention;

[0035] Figure 4 A schematic diagram of the slag filling position in the process provided by the present invention;

[0036] In the figure: 1. pouring channel; 2. steel injection port end of the mold; 3. riser end of the mold; 4. steel injection port end; 5. riser end; 6. clamping electrode; 7. water-cooled crystallizer wall; 8. feeding position; 9. consumable electrode. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0038] See also Figures 1 to 4 The present invention provides the following technical solution: a rare earth efficient homogeneous strengthening special steel die casting - electroslag remelting coupling process, comprising the following steps:

[0039] S1: Hang the rare earth rod in the mold of the die casting, where the mass of the rare earth rod is calculated by the mass of the mold casting steel liquid and the element content in the rare earth rod, the formula is as follows:

[0040]

[0041] Among them: M1-rare earth rod mass, M2-molten steel mass in the mold, ω1-rare earth content in the rare earth rod, ω2-target rare earth content in the molten steel.

[0042] S2: Using a conventional electric arc furnace to melt scrap steel and add refined slag;

[0043] S3: After a certain period of time, the ladle is transferred to the LF process for further cleaning of the molten steel, and alloying and alloying are performed at the end;

[0044] S4: Sent to the VD refining process, deep degassing the molten steel under vacuum conditions, so that the oxygen content in the molten steel is 30-100ppm, the sulfur content is lower than 150ppm, and the tapping temperature is ensured to be 1550-1560℃;

[0045] S5: The molten steel obtained in step S2 enters the mold from the bottom through the runner, melts the rare earth rod after it contacts it, and obtains an ingot after it cools, solidifies, and is demolded, and the positions of the riser and the steel injection port are marked;

[0046] S6: forging the ingot obtained in step S5 into a consumable electrode 9 of corresponding diameter for use in the electroslag remelting process, and taking steel samples at the riser and the steel pouring port to detect the rare earth content in the steel;

[0047] S7: welding the clamping electrode 6 at the steel pouring port position of the consumable electrode 9, and preparing for electroslag remelting with the riser position as the melting tip;

[0048] S8: Calculate the mass of rare earth oxide slag required for remelting based on the mass of the electroslag ingot and the size of the crystallizer;

[0049] S9: weighing and proportioning the refined slag according to the calculated mass and the corresponding ratio, and baking it in an oven;

[0050] S10: The crystallizer, graphite electrode and consumable electrode 9 are prepared, the baked refined slag is loaded into the crystallizer, and power is turned on to start slagging;

[0051] S11: After slag melting is completed, the consumable electrode 9 is replaced and smelting begins;

[0052] S12: After the electroslag containing rare earth oxides is completely melted under the action of the graphite electrode, the consumable electrode 9 prepared in S7 is inserted into the crystallizer to start electroslag remelting;

[0053] S13: During the remelting process, reducing agent is added to the molten pool from time to time until the electrode is completely melted.

[0054] S14: After remelting is completed, samples are taken from the upper and lower ends of the steel to test the material's strength and room temperature impact toughness.

[0055] In this embodiment, in step S1, the mold used is a rectangular mold for steel ingots. In steps S2 to S4, an electric arc furnace is used to smelt 15 tons of molten steel at a time, and the refining slag used in the LF furnace refining process is CaO-Al2O3-SiO2-MgO; in the VD process, the molten steel is deeply deoxidized by feeding wire to ensure that the oxygen content in the molten steel meets the casting requirements.

[0056] In the step S6, the La content in the steel is determined by ICP-OES, and the electroslag remelting rate is adjusted according to the difference in La content at both ends. In the steps S8-9, the total slag amount of the refined slag needs to be calculated in combination with the cross-sectional area of ​​the crystallizer to ensure that the slag layer thickness is 240-300 mm, and it is specifically necessary to consider the smelting steel type, the size of the electroslag ingot, the size of the crystallizer and other factors. The slag drying temperature should be between 700 and 1000 ° C, and the slag drying time should be 5 to 10 hours. In the step S10, when using graphite electrodes to slag, the furnace mouth voltage is 40-60V, and the current is about 8000-9500A. To ensure that the slag composition is uniform, the slag time must be at least 30 minutes. In the steps S11-13, the furnace mouth voltage gradually decreases from 55V to 40V during the smelting process, and the current decreases from 8000-9000A to 7000-8000A.

[0057] Example 1

[0058] This embodiment is based on the 1t H13 steel electroslag remelting process, and the details are as follows:

[0059] (1) Add scrap steel to the ladle through an electromagnet, and start the electrode to energize and begin melting. After the scrap steel is completely melted, add LF refining slag to the surface of the molten steel, and transfer the ladle to the LF furnace for refining for 35 minutes. After refining, take samples to test the composition of the molten steel, calculate the amount of alloy material added, and determine whether to enter the VD furnace refining stage. After the alloy material is added, continue to heat the molten steel to 1630℃, and then transfer the ladle to the VD furnace for vacuum wire feeding deoxidation refining.

[0060] (2) During the steelmaking process, the rare earth rod was fixed in the middle of the mold using a discarded oxygen lance, and a layer of graphite slag was laid on the bottom. The composition of the slag is shown in Table 1. Three minutes before steelmaking, argon was used to fill the mold and runner cavity to ensure the protection of the inert atmosphere.

[0061] Table 1 Graphite slag composition wt.%

[0062] graphite CaF2 SiO2 Al2O3 CaO 20.0 40.0 20.0 8.0 12.0

[0063] The density of graphite slag is 3600kg / m3 and the thickness is 30mm.

[0064] (3) The diameter of the rare earth rod is 18 mm and the length is 1.2 m. The calculation of the rare earth content in the molten steel is based on the mass and size of the rare earth rod. The specific values ​​are shown in Table 2.

[0065] Table 2 Rare earth materials used

[0066]

[0067]

[0068] (3) The VD solidified steel liquid is poured and forged into a consumable electrode ingot with a diameter of 220 mm after solidification. Steel samples are taken at the riser end 5 and the steel injection port end 4 for rare earth content testing. The results show that the average content at the riser end 5 is 350ppm, and the average content at the steel injection port is 507ppm. According to the test results, it is planned to set the electroslag remelting speed to 20-30kg / h for smelting.

[0069] (4) The dimensions of the crystallizer are 300 mm in upper diameter, 340 mm in lower diameter, 1500 mm in height, and 220 mm in thickness of the refining slag layer.

[0070] Mi=2316.2×0.22×3.14×0.152=36kg

[0071] Mh=36×0.18×40 / (977.4×0.255)=1.04kg

[0072] After calculation, the amount of slag required for 1 ton H13 steel crystallizer is 36 kg. The composition of the rare earth reduction slag system is shown in Table 1. The mass of Ca-Si alloy used to reduce lanthanum oxide is 1.04 kg. The total melting time is 240 minutes using the traditional electroslag remelting process.

[0073] Table 3 Rare earth reduction slag kg

[0074] CaF2 Al2O3 La2O3 20.16 8.64 36

[0075] (4) The refined slag is batched according to the calculated initial mass and baked in an oven at 800°C for 4 hours, and then the slag filler is weighed and proportioned.

[0076] (5) The crystallizer, graphite electrode and consumable electrode 9 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging. The furnace port voltage is 48V, the current is 9500A, and the slagging time is set to 35 minutes.

[0077] (6) After slagging is completed, the graphite electrode is pulled out and replaced with the consumable electrode 9 to start smelting. The consumable electrode 9 is placed vertically at the center of the cross section of the crystallizer.

[0078] (7) When the consumable electrode 9 begins to be smelted, add the first batch of reducing agent and add it every 10 minutes. Figure 4 Mark the position, add part of the circulating reducing agent at the four intersections of the mutually perpendicular diameters between the consumable electrode 9 and the inner wall of the crystallizer. Until the end of smelting, the reducing agent is just completely added to the molten pool when the shrinkage feeding starts.

[0079] (8) During the smelting process, the furnace mouth voltage is reduced by 1V and the current is reduced by 100A every 20 minutes.

[0080] (9) After the shrinkage compensation is completed, the power supply is stopped and the electroslag ingot is demoulded after cooling with the furnace for 30 minutes.

[0081] (10) After smelting, the rare earth contents at the center, 1 / 2R and edge of the electroslag were measured at the upper, middle and lower parts, as shown in Table 4. The tempered hardness and room temperature impact toughness were measured at the same positions, and the results are shown in Tables 5 and 6.

[0082] Table 4 Rare earth content of electroslag ingot wt.%

[0083] Center 1 / 2R edge average superior 410 415 418 414.3 middle 422 426 436 428 Down 438 449 452 446.3

[0084] Table 5 Tempering hardness HRC of electroslag ingot

[0085] Center 1 / 2R edge average superior 52.1 52.6 53.0 52.6 middle 53.1 52.9 53.2 53.1 Down 53.6 53.9 54.3 53.9

[0086] Table 6 Electroslag ingot impact absorption energy J

[0087] Center 1 / 2R edge average superior 51.2 51.5 51.3 51.3 middle 52.0 51.8 51.6 51.8 Down 52.3 52.6 52.5 52.5

[0088] Example 2

[0089] This embodiment is based on the 5t H13 steel electroslag remelting process, and the details are as follows:

[0090] (1) Add scrap steel to the ladle through an electromagnet, and start the electrode to energize and begin melting. After the scrap steel is completely melted, add LF refining slag to the surface of the molten steel, and transfer the ladle to the LF furnace for refining for 35 minutes. After refining, take samples to test the composition of the molten steel, calculate the amount of alloy material added, and determine whether to enter the VD furnace refining stage. After the alloy material is added, continue to heat the molten steel to 1630℃, and then transfer the ladle to the VD furnace for vacuum wire feeding deoxidation refining.

[0091] (2) During the steelmaking process, the rare earth rod was fixed in the middle of the mold using a discarded oxygen lance, and a layer of graphite slag was laid on the bottom. The composition of the slag is shown in Table 7. Three minutes before steelmaking, argon was used to fill the mold and runner cavity to ensure the protection of the inert atmosphere.

[0092] Table 7 Graphite slag composition wt.%

[0093] graphite CaF2 SiO2 Al2O3 CaO 20.0 40.0 20.0 8.0 12.0

[0094] The density of graphite slag is 3600kg / m3 and the thickness is 30mm.

[0095] (3) The diameter of the rare earth rod is 18 mm and the length is 1.2 m. The calculation of the rare earth content in the molten steel is based on the mass and size of the rare earth rod. The specific values ​​are shown in Table 8.

[0096] Table 8 Rare earth materials used

[0097]

[0098] (3) The VD solidified steel liquid is poured and forged into a consumable electrode ingot with a diameter of 300 mm after solidification. Steel samples are taken at the riser end 5 and the steel injection port end 4 for rare earth content testing. The average content at the riser end 5 is 156 ppm, and the average content at the steel injection port is 206 ppm. According to the results, the electroslag remelting speed is set at 25-30 kg / h for smelting.

[0099] (4) The dimensions of the crystallizer are upper diameter 620 mm, lower diameter 690 mm, crystallizer height 2000 mm, and refining slag layer thickness 300 mm.

[0100] Mi=2316.2×0.3×3.14×0.152=49.1kg

[0101] Mh=49.1×0.18×40 / (977.4×0.255)=1.42kg

[0102] After calculation, the amount of slag required for 1 ton H13 steel crystallizer is 49.1 kg. The composition of the rare earth reduction slag system is shown in Table 9. The mass of Ca-Si alloy used to reduce lanthanum oxide is 1.42 kg. The total melting time is 260 minutes using the traditional electroslag remelting process.

[0103] Table 9 Rare earth reduction slag kg

[0104] CaF2 Al2O3 La2O3 24.06 10.31 14.73

[0105] (4) The refined slag is batched according to the calculated initial mass and baked in an oven at 800°C for 4 hours, and then the slag filler is weighed and proportioned.

[0106] (5) The crystallizer, graphite electrode and consumable electrode 9 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging. The furnace port voltage is 48V, the current is 9500A, and the slagging time is set to 35 minutes.

[0107] (6) After slagging is completed, the graphite electrode is pulled out and replaced with the consumable electrode 9 to start smelting. The consumable electrode 9 is placed vertically at the center of the cross section of the crystallizer.

[0108] (7) When the consumable electrode 9 begins to be smelted, add the first batch of reducing agent and add it every 11 minutes. Figure 4 Mark the position, add part of the circulating reducing agent at the four intersections of the mutually perpendicular diameters between the consumable electrode 9 and the inner wall of the crystallizer. Until the end of smelting, the reducing agent is just completely added to the molten pool when the shrinkage feeding starts.

[0109] (8) During the smelting process, the furnace mouth voltage is reduced by 1V and the current is reduced by 100A every 20 minutes.

[0110] (9) After the shrinkage compensation is completed, the power supply is stopped and the electroslag ingot is demoulded after cooling with the furnace for 30 minutes.

[0111] (10) After smelting, the rare earth contents at the center, 1 / 2R and edge of the electroslag were measured at the upper, middle and lower parts, as shown in Table 10. The tempered hardness and room temperature impact toughness were measured at the same positions, as shown in Tables 11 and 12.

[0112] Table 10 Rare earth content of electroslag ingot wt.%

[0113] Center 1 / 2R edge average superior 189 193 195 192.3 middle 201 206 212 206.3 Down 223 232 239 231.1

[0114] Table 11 Tempering hardness HRC of electroslag ingot

[0115] Center 1 / 2R edge average superior 52.3 52.6 52.9 52.6 middle 53.3 53.1 53.1 53.2 Down 54.1 54.5 54.2 54.2

[0116] Table 12 Electroslag ingot impact absorption energy J

[0117] Center 1 / 2R edge average superior 52.3 52.6 52.4 52.4 middle 52.5 52.9 52.6 52.6 Down 53.3 53.5 53.4 53.4

[0118] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

[0119] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A rare earth efficient homogeneous strengthening special steel die casting - electroslag remelting coupling process, characterized in that: The process includes the following steps: S1: Hanging a rare earth rod in a die casting mold, wherein the mass of the rare earth rod is calculated based on the mass of the molten steel poured into the mold and the element content in the rare earth rod; S2: smelting through the electric arc furnace scrap melting-refining process; S3: The molten steel obtained in step S2 is fed into the mold from the bottom through the pouring channel, and melted after contacting the rare earth rod. After cooling and solidification, the ingot is demoulded to obtain an ingot, and the positions of the riser and the steel injection port are marked; S4: forging the ingot obtained in step S3 into a consumable electrode suitable for an electroslag remelting process, and taking samples at the riser and the steel pouring port to detect the rare earth content in the steel; S5: welding a clamping electrode at the steel pouring port of the consumable electrode, and using the riser position as the melting tip to prepare for electroslag remelting; S6: After the electroslag containing rare earth oxides is completely melted under the action of the graphite electrode, the consumable electrode prepared in step S4 is inserted into the crystallizer to start electroslag remelting; S7: During the remelting process, reducing agent is added to the molten pool from time to time until the electrode is completely melted.

2. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 1 is characterized in that: In step S1, the material of the rare earth rod hanging must not contaminate the molten steel, and the mass of the rare earth rod is calculated by the following formula: Among them: M1-rare earth rod mass, M2-mould steel liquid mass, ω1-rare earth content in rare earth rod, ω2-rare earth target content in steel liquid.

3. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 1 is characterized in that: In step S2, the oxygen content in the molten steel is 30-100 ppm, the sulfur content is lower than 150 ppm, and the tapping temperature is 1500-1560°C.

4. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 3 is characterized in that: Before pouring, the entire cavity of the mold is filled with argon gas to place the mold in an inert protective atmosphere to prevent secondary oxidation of the molten steel.

5. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 1 is characterized in that: In step S4, the smelting time of electroslag remelting is adjusted according to the difference in rare earth content between the steel pouring port end and the riser end of the consumable electrode to ensure uniform distribution of rare earth elements in the electroslag ingot.

6. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 5 is characterized in that: The total amount of refined slag is such that the thickness of the slag layer is 140 to 200 mm, and the initial composition of the refined slag is 48 to 56 wt.% CaF2-18 to 28 wt.% Al2O3-15 to 35 wt.% La2O3.

7. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 6 is characterized in that: Calculate the target mass M of refined slag according to the size of the target electroslag ingot i And composition: M i =ρ slag ·H·πr 2 Where: slag -slag density, H-slag layer thickness, r-inner diameter of crystallizer.

8. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 7 is characterized in that: According to the target quality M of refined slag i Calculate the mass M of the reducing agent Ca-Si alloy by the composition h : in: -Mass percentage of La2O3 in slag, w Ca -Mass percentage of Ca in Ca-Si alloy.

9. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 1 is characterized in that: In step S7, the start time of adding reducing agent is determined to be when the consumable electrode is inserted into the molten pool to start refining, and the end time of adding reducing agent is determined to be when the electroslag remelting shrinkage feeding starts; the batch addition interval of reducing agent is to divide this time period into 24 equal parts, and add the reducing agent batch by batch according to these intervals.

10. The die casting-electroslag remelting coupling process of rare earth high-efficiency homogeneous strengthening special steel according to claim 1 is characterized in that: The steel injection port is selected as the starting tip of electroslag remelting to carry out the remelting operation; the slag is periodically replenished at the gap between the electrode and the inner wall of the crystallizer.

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