A method for manufacturing a mother electrode of a kovar alloy

Abstract

The present application relates to the field of Kovar alloy production, and particularly relates to a preparation method of a Kovar alloy mother electrode, comprising: loading raw materials into an electric arc furnace for smelting to obtain a first mixture, wherein the raw materials comprise iron-nickel-cobalt scrap and first auxiliary materials; loading the first mixture into an AOD furnace for blowing to obtain a second mixture; and loading the second mixture, nickel, iron, cobalt and manganese into a vacuum induction furnace for smelting to obtain the Kovar alloy mother electrode. In the present application, high temperature in the electric arc furnace promotes oxidation of impurities on the surface of scrap steel into gas or slag, and by adding limestone, fluorite and other slagging agents, an alkaline furnace (CaO~MgO~SiO2) is formed to adsorb silicon oxide, phosphorus oxide and other inclusions. When the AOD furnace is used for blowing, oxygen or argon is blown in to promote the aggregation and floating of inclusions to the slag layer, and by adding silicon iron, aluminum powder and other reducing agents, part of the oxidized inclusions are reduced and deoxidized, the oxygen content is reduced, and the gas content and inclusion grade of the Kovar alloy mother electrode are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of Kovar alloy production, and particularly relates to a preparation method of a Kovar alloy mother electrode. BACKGROUND

[0002] Kovar alloy is a typical Fe-Ni-Co hard glass sealing alloy internationally, which has similar linear expansion coefficient to borosilicate hard glass at 20-450 DEG C, higher Curie point, and good low-temperature structure stability, and has stable performance after long-term use in aviation factory. The alloy is mainly used for glass sealing of electric vacuum components such as emission tube, oscillation tube, ignition tube, magnetron, transistor, sealed plug, relay, lead-out wire of integrated circuit, chassis, housing, support and the like. In application, the expansion coefficients of the selected glass and the alloy should be matched. The low-temperature structure stability should be strictly tested according to the use temperature. Proper heat treatment should be carried out in the processing process to ensure that the material has good deep drawing performance. When the forged material is used, the air tightness should be strictly tested.

[0003] With the vigorous development of industry, the demand for Kovar alloy foil is increasing, and the performance and processing requirements of the Kovar alloy foil are increasing. The main factors restricting the production of the Kovar alloy foil at present are as follows: the gas content of the alloy ingot for producing the Kovar alloy foil is high; and the inclusions of the alloy ingot for producing the Kovar alloy foil are high. At present, the production of the Kovar alloy ingot is mainly in two or three links. The two links are vacuum melting + electroslag remelting, and the three links are vacuum melting + electroslag remelting + consumable remelting. Whether the three links or the two links, both are to reduce the gas content and inclusions of the Kovar alloy ingot, but the filtering capacity of the two processes for the inclusions and the gas is ultimately limited.

[0004] Therefore, how to reduce the gas content and inclusion grade of the Kovar alloy mother electrode is a research direction at present. SUMMARY

[0005] (I) Invention purpose

[0006] The purpose of the present application is to provide a preparation method of a Kovar alloy mother electrode, which can reduce the gas content and inclusion grade of the Kovar alloy mother electrode.

[0007] (II) Technical solution

[0008] In order to solve the above problems, the present application provides a preparation method of a Kovar alloy mother electrode, comprising:

[0009] The raw materials are loaded into an electric arc furnace for smelting to obtain a first mixture, and the raw materials include iron-nickel-cobalt scrap and a first auxiliary material;

[0010] The first mixture is loaded into an AOD furnace for blowing to obtain a second mixture;

[0011] The second mixture, nickel, iron, cobalt and manganese are charged into a vacuum induction furnace for smelting to obtain a canva alloy mother electrode.

[0012] In another aspect of the present application, preferably, the first auxiliary material comprises: aluminum powder and first lime;

[0013] The iron-nickel-cobalt waste material, aluminum powder and first lime are charged in a ratio of 1:0.5%-0.7%:2.5%-3% by furnace load.

[0014] In another aspect of the present application, preferably, the first auxiliary material further comprises fluorite or second lime; the iron-nickel-cobalt waste material and second lime are charged in a ratio of 1:0.5%-2% by furnace load, and the mass ratio of the second lime and fluorite is 5:1-4:1.

[0015] In another aspect of the present application, preferably,

[0016] The raw materials are charged into an electric arc furnace for smelting to obtain a first mixture, comprising:

[0017] The raw materials are charged into an electric arc furnace for smelting to obtain a first mixture, comprising:

[0018] Oxygen is blown into the top of the first steel liquid, and the blowing of oxygen is stopped after the iron-nickel-cobalt waste material is completely melted.

[0019] Argon is blown into the side or bottom of the first steel liquid, and stirring is performed for a second time.

[0020] The first steel liquid is discharged after being at a first temperature for a third time to obtain a first mixture.

[0021] In another aspect of the present application, preferably,

[0022] The first time is 15-25 min, the second time is 5-15 min, the oxygen flow rate is 1000-3000 m 3 / h, the argon flow rate is 200-500 m 3 / h, the first temperature is 1500-1600℃, the third time is 45-65 min, the discharging condition comprises that the temperature reaches 1600-1700℃, and the content of P and the content of S in the first steel liquid are both less than or equal to 0.02%.

[0023] In another aspect of the present application, preferably,

[0024] The first mixture is charged into an AOD furnace for blowing to obtain a second mixture, comprising:

[0025] The first mixture is transported to the AOD furnace through a tundish to obtain a second steel liquid.

[0026] blowing mixed gas into the second molten steel for a fourth time, the mixed gas comprising oxygen and argon;

[0027] adding alloy and first deoxidizer to the second molten steel for a fifth time;

[0028] casting when the temperature of the second molten steel reaches a second temperature to obtain a second mixture, and using argon for protection during casting.

[0029] In another aspect of the present application, preferably,

[0030] The volume ratio of oxygen to argon in the mixed gas is 0.5-1.5:8.5-9.5;

[0031] The gas flow of the mixed gas is 900-1200 NL / h, and the fourth time is 30-50 min;

[0032] The alloy is ferrosilicon, the first deoxidizer is aluminum powder, and the fifth time is 8-12 min; the adding amount of the alloy is 5%-10% of the charging amount of the ferro-nickel-cobalt scrap, and the adding amount of the first deoxidizer is 0.4%-0.5% of the charging amount of the ferro-nickel-cobalt scrap;

[0033] The second temperature is 1520-1580℃, and the gas flow of the argon is 180-300 NL / h.

[0034] In another aspect of the present application, preferably,

[0035] Charging the second mixture, nickel, iron, cobalt and manganese into a vacuum induction furnace for smelting to obtain a kanthal alloy mother electrode, comprising:

[0036] Determining a return ratio of the second mixture, calculating the adding amount of nickel, iron, cobalt and manganese according to the return ratio, and weighing raw materials of the second mixture, nickel, iron, cobalt and manganese according to the return ratio and the adding amount;

[0037] Pretreating the raw materials of the second mixture, nickel, iron, cobalt and manganese;

[0038] Charging the pretreated raw materials of the second mixture, nickel, iron and cobalt into a vacuum induction furnace;

[0039] Smelting by using the vacuum induction furnace to obtain a third molten steel, the smelting comprising: heating by using a first melting power for a sixth time at a first vacuum degree, and heating by using a second melting power for a seventh time at a second vacuum degree;

[0040] Refining the third molten steel;

[0041] In the third molten steel refined to the eighth time, argon is filled, manganese raw material is added, and then pouring and demolding are carried out to obtain the kanva alloy mother electrode.

[0042] In another aspect of the present application, preferably,

[0043] The return ratio is 0 < return ratio ≤ 80%;

[0044] The addition amount of nickel, iron, cobalt and manganese includes calculation by using the following formula:

[0045] The addition amount of nickel is (28.5-29.5% - return ratio * percentage of nickel in the second mixture) * charging amount;

[0046] The addition amount of cobalt is (16.8-17.8% - return ratio * percentage of cobalt in the second mixture) * charging amount;

[0047] The addition amount of manganese is (0.5% - return ratio * percentage of manganese in the second mixture) * charging amount;

[0048] The addition amount of iron is charging amount - weight of the second mixture - addition amount of nickel - addition amount of cobalt - addition amount of manganese.

[0049] In another aspect of the present application, preferably,

[0050] The pretreatment includes:

[0051] The surface of the second mixture is polished or polished to be rust-free and oil-free;

[0052] The raw material of nickel is baked at 800℃ for ≥6h, the raw materials of iron and cobalt are kept dry, and the raw material of manganese is baked at a temperature of 80-180℃ for at least 24 hours;

[0053] The first vacuum degree is 17-30pa, the first melting power is 80-150KW, the second vacuum degree is 30-90pa, and the second melting power is 380-450KW;

[0054] The sixth time is 1-2h, the seventh time is 4-6h, and the eighth time is 45-60min;

[0055] The refining temperature is 1530-1590℃, and the second deoxidizer is added during refining and degassing;

[0056] The pouring mode is top pouring, and the pouring temperature is 1520-1590℃;

[0057] The cooling time of demolding is greater than or equal to 8 hours.

[0058] (Three) beneficial effects

[0059] The above technical solutions of the present application have the following beneficial technical effects:

[0060] The present application promotes the oxidation of impurities on the surface of scrap steel into gas or slag by high temperature in the electric arc furnace, forms an alkaline furnace (CaO ~ MgO ~ SiO2) by adding limestone, fluorite and other slagging agents to adsorb silicon oxide, phosphorus oxide and other inclusions. When using the AOD furnace for blowing, the inclusions are promoted to gather and float to the slag layer by blowing in oxygen or argon, and by adding ferrosilicon, aluminum powder and other reducing agents, the oxide inclusions are reduced and deoxidized, the oxygen content is reduced, and the gas content and inclusion level of the Kovar alloy electrode are reduced. The gas content of the Kovar alloy electrode produced by the present application is below 1.0 ppm, the inclusions are mainly D-type inclusions (fine wires) and the level is below 0.5 level, and the use of the Kovar alloy electrode produced by the present application can significantly improve the yield of subsequent hot working. The use of the Kovar alloy electrode produced by the present application can effectively improve the yield of subsequent foil rolling and ensure good surface quality. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 is the overall flow chart of one embodiment of the present application. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present application more clear and explicit, the present application will be further described in detail below in combination with specific embodiments and with reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0063] Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0064] In the description of the present application, it should be noted that the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0065] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0066] EMBODIMENT

[0067] A preparation method of a Kovar alloy electrode, Figure 1 The overall flow chart of one embodiment of the present application is shown as Figure 1 as shown, comprising:

[0068] The raw materials are charged into an electric arc furnace for smelting to obtain a first mixture, the raw materials including iron-nickel-cobalt waste and a first auxiliary material; the iron-nickel-cobalt waste meets the requirements of no moisture, no oil stains, no air tank, etc. closed container, and the size of the material should not be too large, preferably ≤20 cm to prevent bridging; the first auxiliary material includes aluminum powder and first lime; the iron-nickel-cobalt waste, aluminum powder and first lime are in a ratio of 1:0.5%-0.7%:2.5%-3% by weight. In this embodiment, the aluminum powder needs to be dried before use, the particle size of the aluminum powder is 0.3-0.9 mm, the water content of the aluminum powder is <1.20%, and Al is >95%. The CaO content in the first lime is >90%, the sulfur content is <0.1%, and the first lime entering the furnace requires water content <0.3%; the first auxiliary material further includes fluorite or second lime; the iron-nickel-cobalt waste and the second lime are in a ratio of 1:0.5%-2% by weight, and the mass ratio of the second lime to fluorite is 5:1-4:1. When the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is viscous, fluorite is added, and when the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is thin, second lime is added. The fluorite requires a content of >85%, SiO2<4%, CaO<5%, S<0.1%, and H2O<0.5%, and should be dried at a low temperature of 120-150°C for 5 hours before use.

[0069] Further, in this embodiment, the raw materials are charged into an electric arc furnace for smelting to obtain a first mixture, including:

[0070] The raw materials are charged into an electric arc furnace for smelting to obtain a first mixture, the raw materials including iron-nickel-cobalt waste and a first auxiliary material; the iron-nickel-cobalt waste meets the requirements of no moisture, no oil stains, no air tank, etc. closed container, and the size of the material should not be too large, preferably ≤20 cm to prevent bridging; the first auxiliary material includes aluminum powder and first lime; the iron-nickel-cobalt waste, aluminum powder and first lime are in a ratio of 1:0.5%-0.7%:2.5%-3% by weight. In this embodiment, the aluminum powder needs to be dried before use, the particle size of the aluminum powder is 0.3-0.9 mm, the water content of the aluminum powder is <1.20%, and Al is >95%. The CaO content in the first lime is >90%, the sulfur content is <0.1%, and the first lime entering the furnace requires water content <0.3%; the first auxiliary material further includes fluorite or second lime; the iron-nickel-cobalt waste and the second lime are in a ratio of 1:0.5%-2% by weight, and the mass ratio of the second lime to fluorite is 5:1-4:1. When the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is viscous, fluorite is added, and when the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is thin, second lime is added. The fluorite requires a content of >85%, SiO2<4%, CaO<5%, S<0.1%, and H2O<0.5%, and should be dried at a low temperature of 120-150°C for 5 hours before use.

[0071] blowing oxygen into the top of the first molten steel, stopping blowing oxygen after the iron-nickel-cobalt scrap is completely melted; blowing argon into the side or bottom of the first molten steel and stirring for a second time; blowing oxygen into the top of the first molten steel to promote the oxidation of impurities on the surface of the scrap steel, generating gas or slag, and the oxygen blowing can also increase the temperature of the molten steel and accelerate the melting of the scrap steel; after stopping blowing oxygen, blowing argon into the side or bottom of the first molten steel and stirring the first molten steel for a second time to promote homogenization of the composition and prevent local overheating. Impurities are removed by oxygen oxidation, and argon stirring promotes uniform composition. This stage is a low-temperature stage, and primarily completes the preliminary melting of the scrap steel and the removal of impurities. Further, a pulse-type oxygen / argon alternating blowing mode is adopted, for example: high-frequency short-pulse oxygen + low-frequency long-pulse argon. The inclusion is oxidized by instantaneous high-pressure oxygen, and the argon pulse enhances the stirring force of the molten pool to promote the floating efficiency of the inclusion. The oxygen pulse frequency is 5-10 Hz, the argon pulse frequency is 1-2 Hz, and the mixed gas volume ratio is adjusted to oxygen: argon = 1:4-1:6, which can further reduce the oxygen content to below 0.5 ppm.

[0072] The first molten steel is discharged from the furnace after being at the first temperature for a third time to obtain a first mixture. The first time is 15-25 min, the second time is 5-15 min, the oxygen flow rate is 1000-3000 m 3 / h, the argon flow rate is 200-500 m 3 / h, the first temperature is 1500-1600°C, the third time is 45-65 min, and the discharge conditions include a temperature of 1600-1700°C. The content of P and the content of S in the first molten steel are both less than or equal to 0.02%. Blowing argon and stirring the molten steel promote the inclusion to float to the slag layer. This stage lasts for 45-65 minutes to ensure that the composition of the molten steel is uniform and the inclusion is sufficiently removed.

[0073] The temperature in the electric arc furnace is as high as 3000°C. High-temperature oxidation promotes the oxidation of impurities on the surface of the scrap steel into gas or slag. By adding limestone, fluorite and other slagging agents, an alkaline furnace (CaO-MgO-SiO2) is formed to adsorb inclusions such as silicon oxide and phosphorus oxide. By blowing oxygen or argon and stirring, the inclusions are promoted to gather and float to the slag layer. By oxygen oxidation and argon stirring, impurities such as phosphorus and sulfur in the molten steel are effectively removed, significantly reducing the P and S content (≤0.02%), and the alkaline slag adsorbs the inclusions. Gas blowing and stirring promote the floating of the inclusions, further improving the purity.

[0074] The first mixture is charged into an AOD furnace for blowing to obtain a second mixture; including:

[0075] The first mixture is transported to the AOD furnace through a tundish to obtain a second molten steel; the first mixture is transported from the electric arc furnace to the AOD furnace through the tundish to ensure that the temperature loss is minimized during the transfer process;

[0076] blowing mixed gas into the second molten steel for a fourth time, the mixed gas comprising oxygen and argon; the volume ratio of oxygen to argon in the mixed gas being 0.5-1.5:8.5-9.5; the gas flow rate of the mixed gas being 900-1200 NL / h, and the fourth time being 30-50 min; the oxygen being used to oxidize impurities in the molten steel, and the argon being used to stir the molten steel, and the argon stirring being conducive to the floating of inclusions and the promotion of composition homogenization; and the composition of the molten steel being precisely adjusted by controlling the flow rate and ratio of the mixed gas;

[0077] adding an alloy and a first deoxidizer to the second molten steel within a fifth time; the alloy being ferrosilicon, and the first deoxidizer being aluminum powder, and the fifth time being 8-12 min; the addition amount of the alloy being 5%-10% of the amount of the iron-nickel-cobalt scrap charged into the furnace; the addition amount of the first deoxidizer being 0.4%-0.5% of the amount of the iron-nickel-cobalt scrap charged into the furnace; the molten steel temperature being too low, and the ferrosilicon being added to release heat and increase the molten steel temperature; the ferrosilicon also being able to adjust the silicon content of the second molten steel and improve the flowability and deoxidation effect of the second molten steel; and the aluminum powder being added to reduce part of the oxide inclusions; further, the first deoxidizer being a nano aluminum-magnesium composite deoxidizer (Al-Mg@C core-shell structure, particle size 50-100 nm), and the high specific surface area of the nano particles being used to enhance the deoxidation efficiency and simultaneously inhibit secondary oxidation. The addition amount of the nano aluminum-magnesium composite deoxidizer being 0.2%-0.3% of the amount of the iron-nickel-cobalt scrap charged into the furnace, and the oxygen content being able to be additionally reduced by 20%. The Al-Mg@C core-shell structure refers to a special structure in which an aluminum-magnesium alloy or a mixture thereof is taken as a core, and a layer of carbon material is wrapped outside.

[0078] pouring when the temperature of the second molten steel reaches a second temperature to obtain a second mixture, and using argon to protect during the pouring, the second temperature being 1520-1580℃, and the gas flow rate of the argon being 180-300 NL / h, the argon valve being opened 1 min before the pouring and being closed after the pouring.

[0079] charging the second mixture, nickel, iron, cobalt and manganese into a vacuum induction furnace to be smelted to obtain a canva alloy mother electrode, comprising:

[0080] determining a return ratio of the second mixture, calculating the dosing amount of nickel, iron, cobalt and manganese according to the return ratio, and weighing raw materials of the second mixture, nickel, iron, cobalt and manganese according to the return ratio and the dosing amount; wherein the composition of the canva alloy mother electrode of the embodiment comprises: C≤0.02%, Mn≤0.50%, Si≤0.30%, P≤0.020%, S≤0.020%, Cu≤0.20%, Cr≤0.20%, Mo≤0.20%, Al≤0.10%, Mg≤0.02%, Ti≤0.10%, Ni=28.5~29.5%, Co=16.8~17.8%, and the return ratio is: 0<return ratio≤80%;

[0081] The dosing amount of nickel, iron, cobalt and manganese comprises calculating by using the following formula:

[0082] The dosing amount of nickel is: (28.5~29.5%-return ratio*percentage of nickel in the second mixture)*furnace charging amount;

[0083] The dosing amount of cobalt is: (16.8~17.8%-return ratio*percentage of cobalt in the second mixture)*furnace charging amount;

[0084] The dosing amount of manganese is: (0.5%-return ratio*percentage of manganese in the second mixture)*furnace charging amount;

[0085] The dosing amount of iron is: furnace charging amount-second mixture weight-dosing amount of nickel-dosing amount of cobalt-dosing amount of manganese.

[0086] The raw materials of the second mixture, nickel, iron, cobalt and manganese are pretreated; the pretreatment comprises:

[0087] The surface of the second mixture is polished or polished to be rust-free and oil-free;

[0088] The raw material of the nickel is baked at 800℃ for≥6h, the raw materials of the iron and cobalt are kept dry, and the raw material of the manganese is baked at a temperature of 80~180℃ for at least 24 hours;

[0089] The pretreatment of the refractory material comprises: the baking system of the ingot mold and the riser is baked at 80~180℃ for≥24h, the prefabricated refractory material is used for the tundish, the baking system is baked at 800~900℃ for≥12h, and the intermediate process is strictly controlled, and the items that do not meet the requirements are refused to be executed.

[0090] The pretreated raw materials of the second mixture, nickel, iron and cobalt are loaded into a vacuum induction furnace; the loading mode comprises: cobalt is added at the bottom of the crucible, and the remaining second mixture, nickel and iron are cross-loaded into the furnace, and the total principle of distribution is dense at the bottom and loose at the top;

[0091] The third molten steel is obtained by melting with a vacuum induction furnace, and the melting includes: heating to a sixth time by using a first melting power at a first vacuum degree, and heating to a seventh time by using a second melting power at a second vacuum degree;

[0092] The first vacuum degree is 17-30 pa, the first melting power is 80-150 KW, the second vacuum degree is 30-90 pa, and the second melting power is 380-450 KW; the power is reduced or power is cut off in time when spitting occurs in the melting process; the sixth time is 1-2 h, and the seventh time is 4-6 h;

[0093] The third molten steel is refined, the refining temperature is 1530-1590 DEG C, a second deoxidizer is added and degassing is performed during the refining, argon is filled in the third molten steel after refining for an eighth time, a manganese raw material is added, and then pouring and demolding are performed to obtain the kanthal alloy mother electrode; the eighth time is 45-60 min, the argon filling pressure is 5000-10000 pa, the metal manganese is added, and stirring is performed for 10-15 min until the molten steel surface is calm and no bubbles are generated;

[0094] The pouring mode is an up-pouring method, a small stream is poured to the hat mouth for supplementary pouring, the hat mouth supplementary pouring time is greater than 1 / 2-2 / 3 of the ingot body supplementary pouring time, and the pouring temperature is 1520-1590 DEG C; after pouring, vacuum is broken and a heating agent is added, the first heating agent is added, and then the second heating agent is added after 10-15 min; the heating agent composition includes 70% industrial aluminum powder and 30% sodium nitrate; the heating agent amount is 0.2-0.6% of the molten steel weight; the demolding cooling time is greater than or equal to 8 hours; the heating agent prolongs the riser molten steel solidification time, slows down the temperature drop, continuously heats and supplements, improves the shrinkage hole shape and the supplementary pouring efficiency, improves the supplementary pouring effect, facilitates the inclusion floating, purifies the molten steel, and improves the ingot quality.

[0095] The present embodiment promotes the oxidation of impurities on the surface of scrap steel into gas or slag by high temperature in the electric arc furnace, and forms an alkaline furnace (CaO~MgO~SiO2) by adding limestone, fluorite and other slagging agents to adsorb silicon oxide, phosphorus oxide and other inclusions. When the AOD furnace is used for blowing, the inclusions are promoted to gather and float to the slag layer by blowing in oxygen or argon, and the content of oxygen is reduced by adding ferrosilicon, aluminum powder and other reducing agents to reduce part of the oxide inclusions and deoxidize, thereby reducing the gas content and inclusion level of the Kovar alloy electrode. The gas content of the Kovar alloy electrode produced by the present application is less than 1.0 ppm, the inclusions are mainly D-type inclusions (fine wires) and the level is less than 0.5, and the use of the Kovar alloy electrode produced by the present application can significantly improve the yield of subsequent hot working due to the low gas content. The use of the Kovar alloy electrode produced by the present application can effectively improve the yield of subsequent foil rolling due to the low inclusion level, and can ensure good surface quality.

[0096] Example 1

[0097] Iron-nickel-cobalt scrap, aluminum powder and first lime are loaded into an electric arc furnace for heating to obtain a first molten steel, and the loading amount of iron-nickel-cobalt scrap, aluminum powder and first lime is 1:0.5%:3%; when the amount of the first molten steel reaches 2 / 3 of the loading amount, 1 / 2 of the total amount of the first lime is added, and the remaining first lime is added after melting; the loading amount of iron-nickel-cobalt scrap and second lime is 1:0.5%, and the mass ratio of second lime and fluorite is 5:1; the addition of fluorite and second lime is based on the flow rate of the first molten steel, and during the smelting process, the viscosity of the slag is high, that is, the phenomenon of dry return occurs, a small amount of fluorite is added in batches through a high-position bin to improve the fluidity of the slag until the fluidity is good; the raw materials are loaded into the electric arc furnace for heating for 15 min, oxygen is blown into the top of the first molten steel, and when the iron-nickel-cobalt scrap is completely melted, the blowing of oxygen is stopped, argon is blown into the side or bottom of the first molten steel, and stirring is carried out for 5 min; when the first molten steel is at 1500℃, the furnace is discharged to obtain a first mixture. The oxygen flow rate is 1000m 3 / h, the argon flow rate is 200m 3 / h, and the discharge conditions include that the temperature reaches 1600℃, the content of P and the content of S in the first molten steel are both less than or equal to 0.02%.

[0098] The first mixture is transported to an AOD furnace through a tundish to obtain a second molten steel;

[0099] blowing mixed gas into the second liquid steel to a fourth time, the mixed gas comprising oxygen and argon, the volume ratio of oxygen to argon in the mixed gas being 0.5:9.5, the gas flow of the mixed gas being 900 NL / h, and the fourth time being 30 min; adding an alloy and a first deoxidizer to the second liquid steel; the adding being completed within 8 min, the alloy being ferrosilicon, the first deoxidizer being aluminum powder, the adding amount of the alloy being 5% of the charging amount of the iron-nickel-cobalt scrap, and the adding amount of the first deoxidizer being 0.4% of the charging amount of the iron-nickel-cobalt scrap; and pouring when the temperature of the second liquid steel reaches a second temperature, the second temperature being 1520°C, to obtain a second mixture, the pouring being protected by argon, and the gas flow of the argon being 180 NL / h.

[0100] charging according to a return ratio of 80%, C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.5%, and Co = 16.8%; pretreating the second mixture, the raw materials of nickel, iron, cobalt, and manganese; polishing the surface of the second mixture to be free of rust and oil stains; baking the raw material of nickel at 800°C for 6 h, keeping the raw materials of iron and cobalt dry, and baking the raw material of manganese at a temperature of 80°C for 24 h; baking the ingot mold and the riser at 100°C for 24 h; and using prefabricated refractory material for the tundish, and baking the tundish at 830°C for 12 h.

[0101] loading the pretreated second mixture, the raw materials of nickel, iron, cobalt, and manganese into a vacuum induction furnace; adding electrolytic cobalt at the bottom of the crucible when loading, adding 1 / 3 of graphite carbon into the furnace, and loading the remaining second mixture, electrolytic nickel, and pure iron into the furnace alternately, and arranging the materials to be dense at the bottom and loose at the top; starting to send power of 80 KW to preheat the materials for 1 h when the first vacuum degree is 17 Pa; lowering the power or stopping power supply in time when spitting occurs during the melting process when the second vacuum degree is 30 Pa, and the second melting power is 380 KW; and the melting time being 4 h;

[0102] adding graphite carbon to degas every 5 min, and appropriately prolonging the time of adding graphite carbon if the reaction is violent and the vacuum degree changes greatly; and the refining temperature being 1530°C, and the time being 45 min;

[0103] filling the furnace with argon of 5000 Pa before tapping, adding metallic manganese, and stirring for 10 min until the liquid steel surface is calm and no bubbles come out, and taking a composition sample, a gas sample, and an expansion sample;

[0104] Pouring under argon protection, pouring method: top pouring method, with slag dam and slag dam in runner, φ35 water gap, pouring to the cap small flow to supplement, pouring temperature: 1520℃, cap shrinkage time is greater than 1 / 2 of the ingot shrinkage time. After pouring, quickly break the vacuum and add the heating agent, after the first pass, wait for 10 minutes to add the second pass of heating agent. The composition of the heating agent: industrial aluminum powder 70%, sodium nitrate 30%; the amount of heating agent is 0.2% of the weight of the molten steel; the mold cooling time after the furnace is out is 8h, and the ingot is removed after the slow cooling pit is slowly cooled for 8h to obtain the mother electrode ingot.

[0105] Example 2

[0106] The iron-nickel-cobalt waste, aluminum powder and first lime are loaded into the electric arc furnace for heating to obtain a first molten steel, the iron-nickel-cobalt waste, aluminum powder and first lime are 1:0.7%:2.5% by loading amount; when the first molten steel reaches 2 / 3 of the loading amount, half of the total amount of first lime is added, and the remaining first lime is added after full melting; the iron-nickel-cobalt waste and the second lime are 1:2% by loading amount, and the mass ratio of the second lime and the fluorite is 4:1; the addition time of the fluorite and the second lime is added according to the flow amount of the first molten steel; during the smelting process, the slag viscosity is high, that is, the dry back phenomenon occurs, a small amount of fluorite is added through the high-position stock bin in batches to improve the fluidity of the slag until the fluidity is good; the raw materials are loaded into the electric arc furnace for heating for 25min, oxygen is blown into the top of the first molten steel, and when the iron-nickel-cobalt waste is completely melted, the blowing of oxygen is stopped, argon is blown into the side or bottom of the first molten steel, and stirring is carried out for 15min; when the first molten steel is at 1600℃, the furnace is discharged to obtain a first mixture. The oxygen flow is 3000m 3 / h, the argon flow is 500m 3 / h, the discharge conditions include that the temperature reaches 1700℃, and the content of P and the content of S in the first molten steel are both less than or equal to 0.02%.

[0107] The first mixture is transported to the AOD furnace through the tundish to obtain a second molten steel;

[0108] A mixed gas including oxygen and argon is blown into the second molten steel for a fourth time, the volume ratio of oxygen to argon in the mixed gas is 1:9, the gas flow of the mixed gas is 1200NL / h, and the fourth time is 50min; an alloy and a first deoxidizer are added to the second molten steel; the addition is completed within 12min, the alloy is ferrosilicon, the first deoxidizer is aluminum powder, the addition amount of the alloy is 10% of the loading amount of the iron-nickel-cobalt waste; the addition amount of the first deoxidizer is 0.5% of the loading amount of the iron-nickel-cobalt waste; pouring is carried out when the temperature of the second molten steel reaches a second temperature, the second temperature is 1580℃, to obtain a second mixture, and argon is used for protection during pouring, and the gas flow of argon is 300NL / h.

[0109] The ingredients are prepared according to the return ratio of 60%, C0.01%, Mn0.5%, Si0.3%, Ni=29.5%, Co=17.8%; the second mixture, the raw materials of nickel, iron, cobalt and manganese are pretreated, the surface of the second mixture is polished to be free of rust and oil stains; the raw material of nickel is baked at 800°C for 7h, the raw materials of iron and cobalt are kept dry, and the raw material of manganese is baked at a temperature of 180°C for 24h; the baking schedule of the ingot mold and the riser is 180°C for 24h, the tundish is pre-baked with refractory material, and the baking schedule is 800°C for 12h.

[0110] The pretreated second mixture, the raw materials of nickel, iron, cobalt and manganese are loaded into a vacuum induction furnace; during loading, electrolytic cobalt is added at the bottom of the crucible, 1 / 3 of the graphite carbon is added into the furnace, and the remaining second mixture, electrolytic nickel and pure iron are cross-loaded into the furnace, and the total principle of distribution is dense at the bottom and loose at the top; when the first vacuum degree is 30pa, 150KW power is supplied to preheat the material for 2h, when the second vacuum degree is 90pa, the second melting power is 450KW, and the power is reduced or the power is cut off in time when spitting occurs during the melting process, and the melting time is 6h;

[0111] Graphite carbon is added every 10min for degassing, and if the carbon addition reaction is violent and the vacuum degree changes greatly, the carbon addition time is appropriately prolonged. The refining temperature is 1590°C, and the time is 60min;

[0112] Before tapping, argon gas is filled into the furnace at 10000pa, metal manganese is added, and stirring is performed for 15min until the steel liquid surface is calm and no bubbles are generated; a composition sample, a gas sample and an expansion sample are taken;

[0113] Argon protection pouring is performed, the pouring mode is up-pouring, a slag dam and a slag blocking device are arranged in the runner, φ35 water gap is used, the pouring temperature is 1590°C, the cap pouring time is greater than 1 / 2 of the ingot body pouring time, and the cap is supplemented and consolidated. After pouring, the vacuum is broken quickly and the heating agent is added, the first pass is completed, and the second pass is added after 15min. The composition of the heating agent is industrial aluminum powder 70% and sodium nitrate 30%; the amount of the heating agent is 0.6% of the weight of the steel liquid; after the furnace is discharged, the mold cooling time is 8h, and the ingot is removed after the ingot is slowly cooled in the slow cooling pit for 8h to obtain the parent electrode ingot.

[0114] Example 3

[0115] Fe-Ni-Co waste, aluminum powder and first lime are charged into an electric arc furnace for heating to obtain a first molten steel, the ratio of Fe-Ni-Co waste, aluminum powder and first lime is 1:0.6%:2.7% by weight of the furnace; when the amount of the first molten steel reaches 2 / 3 of the furnace, 1 / 2 of the total amount of first lime is added, and the remaining first lime is added after melting; the ratio of Fe-Ni-Co waste and second lime is 1:1.5% by weight of the furnace, and the mass ratio of second lime and fluorite is 4.5:1; the addition of fluorite and second lime is based on the flow rate of the first molten steel; during the smelting process, the slag viscosity is high, i.e., the phenomenon of dry back occurs, a small amount of fluorite is added in batches through a high-position bin to improve the fluidity of the slag until the fluidity is good; the raw materials are charged into the electric arc furnace for heating for 20 min, oxygen is blown into the top of the first molten steel, and when the Fe-Ni-Co waste is completely melted, the blowing of oxygen is stopped, argon is blown into the side or bottom of the first molten steel, and stirring is performed for 10 min; when the first molten steel is at 1550°C, the furnace is discharged to obtain a first mixture. The flow rate of oxygen is 2000 m 3 / h, the flow rate of argon is 400 m 3 / h, and the discharge conditions include that the temperature reaches 1650°C, and the contents of P and S in the first molten steel are both less than or equal to 0.02%.

[0116] The first mixture is transported to an AOD furnace through a tundish to obtain a second molten steel;

[0117] Mixed gas including oxygen and argon is blown into the second molten steel for a fourth time, the volume ratio of oxygen to argon in the mixed gas is 1:9.5, the gas flow rate of the mixed gas is 1000 NL / h, and the fourth time is 40 min; an alloy and a first deoxidizer are added to the second molten steel; the addition is completed within 10 min, the alloy is ferrosilicon, the first deoxidizer is aluminum powder, the addition amount of the alloy is 8% of the charging amount of the Fe-Ni-Co waste, and the addition amount of the first deoxidizer is 0.45% of the charging amount of the Fe-Ni-Co waste; when the temperature of the second molten steel reaches a second temperature, pouring is performed, the second temperature is 1560°C, a second mixture is obtained, and argon is used for protection during pouring, and the gas flow rate of argon is 200 NL / h.

[0118] The ingredients are prepared according to a return ratio of 40%, C0.01%, Mn0.5%, Si0.3%, Ni=29%, and Co=17%; the second mixture, nickel, iron, cobalt and manganese raw materials are pretreated, the surface of the second mixture is polished to be rust-free and oil-free; the nickel raw material is baked at 800°C for 7 h, the iron and cobalt raw materials are kept dry, and the manganese raw material is baked at a temperature of 150°C for 24 h; the baking system of the ingot mold and the riser is baking at 150°C for 24 h, the tundish adopts prefabricated refractory material, and the baking system is baking at 800°C for 12 h.

[0119] The pretreated second mixture, raw materials of nickel, iron, cobalt and manganese are charged into a vacuum induction furnace; electrolytic cobalt is added at the bottom of the crucible during charging, 1 / 3 of the graphite carbon is added at the same time, the remaining second mixture, electrolytic nickel and pure iron are charged into the furnace alternately, and the total principle of distribution is dense at the bottom and loose at the top; when the first vacuum degree is 25 Pa, 120 KW power is supplied to preheat the material for 1.5 h, when the second vacuum degree is 60 Pa, the second melting power is 400 KW, and the melting process appears spitting, the power is reduced or the power is cut off in time, and the melting time is 5 h;

[0120] The graphite carbon is added to degas every 8 min, if the carbon addition reaction is violent and the vacuum degree changes greatly, the carbon addition time is appropriately prolonged. The refining temperature is 1550℃, and the time is 50 min;

[0121] Before tapping, argon gas is filled into the furnace at 8000 Pa, metal manganese is added, and stirring is carried out for 12 min until the molten steel surface is calm and no bubbles are generated; the composition sample, gas sample and expansion sample are taken;

[0122] Argon protection pouring, pouring mode: top pouring method, the flow channel is equipped with a slag dam and a strong slag dam, φ35 water gap is adopted, and the pouring temperature is 1550℃; the cap head shrinkage time is greater than 1 / 2 of the ingot body shrinkage time. After pouring, the vacuum is broken quickly and the heating agent is added, the first pass is completed, and the second pass is added after 12 min. The composition of the heating agent: industrial aluminum powder 70%, sodium nitrate 30%; the amount of heating agent is 0.4% of the weight of molten steel; after the furnace is discharged, the mold cooling time is 8 h, and the ingot is removed after the mold is cooled for 8 h in the slow cooling pit to obtain the mother electrode ingot.

[0123] Example 4

[0124] The iron-nickel-cobalt waste, aluminum powder and first lime are charged into an electric arc furnace for heating to obtain a first molten steel, the mass ratio of the iron-nickel-cobalt waste, aluminum powder and first lime is 1:0.55%:2.9% based on the charging amount; when the first molten steel reaches 2 / 3 of the charging amount, half of the total amount of first lime is added, and the remaining first lime is added after complete melting; the mass ratio of the iron-nickel-cobalt waste and second lime is 1:1.7% based on the charging amount, and the mass ratio of the second lime and fluorite is 4.6:1; the addition time of fluorite and second lime is determined according to the flow amount of the first molten steel; during the smelting process, the slag viscosity is high, that is, the dry back phenomenon occurs, a small amount of fluorite is added in batches through a high-position material bin to improve the fluidity of the slag until the fluidity is good; the raw materials are charged into the electric arc furnace for heating for 22 min, oxygen is blown into the top of the first molten steel, and the blowing of oxygen is stopped when the iron-nickel-cobalt waste is completely melted; argon is blown into the side or bottom of the first molten steel, and stirring is carried out for 12 min; the furnace is discharged when the first molten steel is at 1540℃ to obtain a first mixture. The oxygen flow is 2200 m 3 / h, and the argon flow is 350 m 3The tapping conditions include that the temperature reaches 1640℃, the content of P and the content of S in the first molten steel are less than or equal to 0.02%.

[0125] The first mixture is transported to an AOD furnace through a tundish to obtain a second molten steel;

[0126] Mixed gas including oxygen and argon is blown into the second molten steel for a fourth time, the volume ratio of oxygen to argon in the mixed gas is 1:9.2, the gas flow of the mixed gas is 1100 NL / h, the fourth time is 45 min, an alloy and a first deoxidizer are added to the second molten steel, the adding is completed within 10 min, the alloy is ferrosilicon, the first deoxidizer is aluminum powder, the adding amount of the alloy is 6% of the charging amount of the iron-nickel-cobalt scrap, the adding amount of the first deoxidizer is 0.43% of the charging amount of the iron-nickel-cobalt scrap, and the second molten steel is poured when the temperature of the second molten steel reaches a second temperature, the second temperature is 1530℃, a second mixture is obtained, and the pouring is protected by argon, and the gas flow of the argon is 250 NL / h.

[0127] Ingredients are prepared according to a return ratio of 20%, C0.01%, Mn0.5%, Si0.3%, Ni=28.8%, and Co=17.1%; the second mixture, nickel, iron, cobalt and manganese raw materials are pretreated, the surface of the second mixture is polished to be rust-free and oil-free; the nickel raw material is baked at 800℃ for 7 h, the iron and cobalt raw materials are kept dry, and the manganese raw material is baked at a temperature of 120℃ for 24 h; the baking system of the ingot mold and the riser is baking at 120℃ for 24 h, the tundish is made of prefabricated refractory, and the baking system is baking at 800℃ for 12 h.

[0128] The pretreated second mixture, nickel, iron, cobalt and manganese raw materials are charged into a vacuum induction furnace; electrolytic cobalt is added at the bottom of the crucible when charging, 1 / 3 of the graphite carbon is added into the furnace, and the remaining second mixture, electrolytic nickel and pure iron are cross-charged into the furnace, and the total principle of the distribution is dense at the bottom and loose at the top; when the first vacuum degree is 27 pa, 110 KW power is started to preheat the material for 1.3 h, when the second vacuum degree is 70 pa, the second melting power is 420 KW, and the power is reduced or the power is stopped in time when spitting occurs in the melting process, and the melting time is 5.5 h.

[0129] The graphite carbon is added to degas every 9 min, if the carbon addition reaction is violent and the vacuum degree changes greatly, the carbon addition time is appropriately prolonged. The refining temperature is 1560℃, and the time is 1 h.

[0130] 7000 pa of argon is filled into the furnace before tapping, metal manganese is added, and stirring is performed for 13 min until the molten steel surface is calm and no bubbles are generated, a composition sample, a gas sample and an expansion sample are taken.

[0131] Pouring under argon protection, pouring method: top pouring, with slag dam and slag dam in runner, φ35 nozzle is used, pouring to cap mouth small flow to supplement, pouring temperature: 1550℃, cap mouth supplement time is more than 1 / 2 of ingot body supplement time. After pouring, vacuum is broken quickly and heating agent is added, after first time addition, second time addition is added after 12 minutes. Heating agent composition: industrial aluminum powder 70%, sodium nitrate 30%; heating agent dosage is 0.5% of steel liquid weight; mold cooling time after furnace discharge is 8h, after ingot demolding, slow cooling in slow cooling pit for 8h to obtain mother electrode ingot.

[0132] Comparative Example

[0133] The return material in the comparative example is prepared according to the following steps:

[0134] Melting is performed by using a medium frequency furnace, and the preparation before melting is as follows: the surface of the remelted material is kept dry and free of foreign matter, and the material containing oil stains, water stains, cutting fluid and other materials is baked at 80-200℃ for ≥5h before being put into the furnace for remelting; the deoxidizer, alloy material, heating agent and refractory material are baked at 50-300℃ for ≥2h; the ingot mold temperature is 50-200℃.

[0135] Melting period: the return steel is loaded into the crucible in order of size, and is tightly loaded at the bottom and sparsely loaded at the top to prevent bridging; high-power power supply is performed, and lime is slowly added when the material is melted and the molten steel is seen; the lime requirements are: 5-50mm (particle size), ≥800℃ baking for more than 24 hours, and the lime is taken out of the heating furnace before use; the lime addition amount is: the loading amount x 1.0-5.0%; after the material is melted, the temperature is measured, and the temperature is adjusted to 1550-1600℃ for the refining period.

[0136] Refining period: argon blowing operation is performed during the refining process, slagging is started, and the total amount of single slagging is: the loading amount * 1.0-3.0%; the fluorite is 10-60mm (particle size), and is baked at 50-250℃ for ≥4h before use; the slag is adjusted, the lime accounts for 80% of the slag material, the weight is ensured, and the fluorite addition amount is appropriately adjusted according to the fluidity of the slag; after the slag has good fluidity, primary deoxidation is performed, deoxidizer A1-Ca0 is added, and the single use amount is: the loading amount * 0.4%; the slag should be lightly and quickly pointed during the slagging process to prevent aluminum penetration; after the slag is ash white, the slag is first removed, and secondary slagging and deoxidation are performed, and the white slag is kept for 60min.

[0137] Pouring: silicon-calcium and nickel-magnesium alloy is added in the furnace, the composition sample is taken, the temperature is measured, and the furnace is discharged, and sponge titanium is added in the ladle; the steel discharge temperature is: 1610-1650℃, the holding time is: 2 minutes-4 minutes and 30 seconds; the demolding time is ≥6h.

[0138] Comparative Example 1

[0139] Using the return material described above, the return ratio is 0, and the ingredients are C 0.01%, Mn 0.35%, Si 0.3%, Ni=28.8%, and Co=17.1%, and the remaining steps are the same as those in Example 4.

[0140] Comparative Example 2

[0141] Using the return material described above, the return ratio is 60%, and the ingredients are C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.8%, Co = 17.1%, and the remaining steps are the same as Example 2.

[0142] Comparative Example 3

[0143] Using the return material described above, the return ratio is 40%, and the ingredients are C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.8%, Co = 17.1%, and the remaining steps are the same as Example 3.

[0144] The gas content and inclusions of the Kanthal alloy mother electrode produced by the process are measured for Examples 1-4 and Comparative Examples 1-3. Table 1 shows the gas content of Examples 1-4 and Comparative Examples 1-3, and the detection values of the gas content are as follows:

[0145] Table 1: Determination of gas content of Examples 1-4 and Comparative Examples 1-3:

[0146] Case O / ppm N / ppm H / ppm Example 1 0.72 0.52 0.02 Example 2 0.98 0.56 0.05 Example 3 0.88 0.49 0.07 Example 4 1.02 0.82 0.1 Comparative Example 1 13.28 5.85 1.57 Comparative Example 2 15.87 4.36 1.34 Comparative Example 3 18.32 5.73 1.62

[0147] Analyzing the above data, the average O content in Examples 1-4 is 0.9 ppm, the average N content is 0.5975 ppm, and the average H content is 0.06 ppm. The average O content in Comparative Examples 1-3 is 15.82 ppm, the average N content is 5.313 ppm, and the average H content is 1.51 ppm.

[0148] Table 2 shows the inclusion content of Examples 1-4 and Comparative Examples 1-3, and the detection values of the inclusion content are as follows:

[0149] Table 2: Determination of inclusion content of Examples 1-4 and Comparative Examples 1-3:

[0150]

[0151]

[0152] In Examples 1-4, the main inclusions are D-type inclusions (spherical oxides), and according to the GB / T 10561-2005 "Standard Grading Diagram Microscopic Examination Method for Determination of Non-metallic Inclusions in Steel", the 0.5 level of D-type inclusions corresponds to 1 inclusion on the detection surface, the 1.0 level corresponds to 4 inclusions, and the 1.5 level corresponds to 9 inclusions. In Comparative Examples 1-3, there are B-type inclusions (oxides) and D-type inclusions (spherical oxides), and the types of inclusions are more and the levels are higher.

[0153] In summary, the Canival alloy ingot produced by the present embodiment has the characteristics of high purity due to its low oxygen content and low inclusion, and can provide high-quality steel ingots for subsequent processing of the Canival alloy.

[0154] It should be understood that the above specific embodiments of the present application are merely used for illustrative or explanatory purposes, and do not constitute a limitation on the present application. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the appended claims of the present application are intended to cover all variations and modifications falling within the scope and boundary of the appended claims, or the equivalent forms of such scope and boundary.

[0155] The present application has been described above with reference to embodiments. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, various substitutions and modifications can be made by those skilled in the art, and all such substitutions and modifications shall fall within the scope of the present application.

[0156] Although the embodiments of the present application have been described in detail, it should be understood that various changes, substitutions and modifications can be made to the embodiments of the present application without departing from the spirit and scope of the present application.

[0157] Obviously, the above-described embodiments are merely examples for clarity, and are not a limitation on the embodiments. Based on the above description, other different forms of changes or modifications can be made by those skilled in the art. It is not necessary or possible to exhaust all embodiments here. The obvious changes or modifications derived therefrom are still within the protection scope of the present application.

Claims

1. A method of producing a Kovar alloy mother electrode, characterized by, The preparation method of the Kovar alloy electrode comprises the following steps: raw materials are put into an electric arc furnace for smelting to obtain a first mixture, wherein the raw materials comprise iron-nickel-cobalt waste and a first auxiliary material; the first mixture is put into an AOD furnace for blowing to obtain a second mixture; the second mixture, nickel, iron, cobalt and manganese are put into a vacuum induction furnace for smelting to obtain a Kovar alloy electrode; the first auxiliary material comprises aluminum powder and first lime; the iron-nickel-cobalt waste, aluminum powder and first lime are in a ratio of 1:0.5%-0.7%:2.5%-3% by weight; the step of smelting the raw materials in the electric arc furnace to obtain the first mixture comprises the following steps: the raw materials are put into the electric arc furnace for heating for a first time to obtain a first molten steel; oxygen is blown into the top of the first molten steel, and the blowing of oxygen is stopped when the iron-nickel-cobalt waste is completely melted; argon is blown into the side or bottom of the first molten steel, and the first molten steel is stirred for a second time; the first molten steel is taken out of the electric arc furnace after being at a first temperature for a third time to obtain the first mixture; The first time is 15-25 min, the second time is 5-15 min; the oxygen flow is 1000-3000 m 3 / h, the argon flow is 200-500 m 3 / h, the first temperature is 1500-1600 DEG C, the third time is 45-65 min, the tapping condition includes that the temperature reaches 1600-1700 DEG C, the content of P and the content of S in the first liquid steel are less than or equal to 0.02%. the step of blowing the first mixture in the AOD furnace to obtain the second mixture comprises the following steps: the first mixture is transported to the AOD furnace through a tundish to obtain a second molten steel; mixed gas comprising oxygen and argon is blown into the second molten steel for a fourth time; alloy and a first deoxidizer are added to the second molten steel within a fifth time; the second molten steel is poured when the temperature of the second molten steel reaches a second temperature to obtain the second mixture, and argon is used for protection during pouring; the volume ratio of oxygen to argon in the mixed gas is 0.5-1.5:8.5-9.5; the gas flow of the mixed gas is 900-1200 NL / h, and the fourth time is 30-50 min; the alloy is ferrosilicon, the first deoxidizer is aluminum powder, and the fifth time is 8-12 min; the addition amount of the alloy is 5%-10% of the weight of the iron-nickel-cobalt waste, and the addition amount of the first deoxidizer is 0.4%-0.5% of the weight of the iron-nickel-cobalt waste; the second temperature is 1520-1580℃, and the gas flow of the argon is 180-300 NL / h.

2. The method of claim 1, wherein the vanadium alloy master electrode is prepared by the steps of: The first auxiliary material further comprises fluorite or second lime; the fluorite is added when the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is in a viscous state, and is added until the flowability is good; the second lime is added when the flowability of the mixed slag of the iron-nickel-cobalt waste, aluminum powder and first lime is in a thin and thick state, and is added until the flowability is good.

3. The preparation method of the Kovar alloy electrode according to claim 1, wherein the step of smelting the second mixture, nickel, iron, cobalt and manganese in the vacuum induction furnace to obtain the Kovar alloy electrode comprises the following steps: a return ratio of the second mixture is determined, the addition amounts of nickel, iron, cobalt and manganese are calculated according to the return ratio, and the raw materials of the second mixture, nickel, iron, cobalt and manganese are weighed according to the return ratio and the addition amounts; the raw materials of the second mixture, nickel, iron, cobalt and manganese are pretreated; the pretreated raw materials of the second mixture, nickel, iron and cobalt are put into the vacuum induction furnace; The third molten steel is obtained by melting in a vacuum induction furnace, the melting including: heating to a sixth time by using a first melting power at a first vacuum degree, and heating to a seventh time by using a second melting power at a second vacuum degree; Refining the third molten steel; After the third molten steel is refined to an eighth time, argon is filled into the third molten steel, a raw material of manganese is added, and then pouring and demolding are performed to obtain the Kovar alloy mother electrode.

4. The method according to claim 3, wherein the return ratio is 0 < return ratio ≤ 80 %; and the amounts of the nickel, the iron, the cobalt and the manganese are calculated by using the following formulas: Nickel amount = (28.5-29.5 % - return ratio * percentage of nickel in the second mixture) * charging amount; Cobalt amount = (16.8-17.8 % - return ratio * percentage of cobalt in the second mixture) * charging amount; Manganese amount = (0.5 % - return ratio * percentage of manganese in the second mixture) * charging amount; Iron amount = charging amount - weight of the second mixture - nickel amount - cobalt amount - manganese amount.

5. The method according to claim 4, wherein the pre-treatment includes: polishing the surface of the second mixture to be free of rust and oil stains; baking the raw material of nickel at 800 °C for ≥ 6 h, keeping the raw materials of iron and cobalt dry, and baking the raw material of manganese at a temperature of 80-180 °C for at least 24 h; the first vacuum degree is 17-30 Pa, the first melting power is 80-150 KW, the second vacuum degree is 30-90 Pa, and the second melting power is 380-450 KW; the sixth time is 1-2 h, the seventh time is 4-6 h, and the eighth time is 45-60 min; the refining temperature is 1530-1590 °C, and the second deoxidizer is added during the refining and degassing is performed; the pouring mode is top pouring, and the pouring temperature is 1520-1590 °C; the cooling time for demolding is ≥ 8 h. ​ ​ ​

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