Preparation method of kovar alloy mother electrode

Abstract

The invention relates to the field of Kovar alloy production, in particular to a Kovar alloy mother electrode preparation method which comprises the steps that raw materials are put into an electric arc furnace to be smelted, a first mixture is obtained, and the raw materials comprise iron-nickel-cobalt waste and a first auxiliary material; the first mixture is loaded into an AOD furnace for blowing, and a second mixture is obtained; and the second mixture, nickel, iron, cobalt and manganese are put into a vacuum induction furnace to be smelted, and the kovar alloy mother electrode is obtained. According to the method, impurities on the surface of the waste steel are promoted to be oxidized into gas or slag through high temperature in the electric arc furnace, slag formers such as limestone and fluorite are added, an alkaline furnace (CaO-MgO-SiO2) is formed, and impurities such as silicon oxide and phosphorus oxide are adsorbed. When the AOD furnace is used for blowing, oxygen or argon is blown in to promote inclusion to gather and float to a slag layer, and reducing agents such as silicon iron and aluminum powder are added to reduce part of oxide inclusion and deoxidize, so that the oxygen content is reduced, and the gas content and the inclusion grade of the kovar alloy mother electrode are reduced.

Description

Technical Field

[0001] The present invention relates to the field of Kovar alloy production, and specifically relates to a preparation method of a Kovar alloy master electrode. Background Art

[0002] Kovar alloy is a typical Fe-Ni-Co hard glass sealing alloy commonly used internationally. This alloy has a linear expansion coefficient similar to that of borosilicate hard glass at 20 - 450 °C, a relatively high Curie point, and good low-temperature tissue stability. After long-term use in aviation factories, its performance is stable. It is mainly used for glass sealing of electro-vacuum components such as transmitting tubes, oscillating tubes, ignitron tubes, magnetrons, transistors, sealed plugs, relays, lead-out wires of integrated circuits, chassis, shells, brackets, etc. In applications, the selected glass should be matched with the expansion coefficient of the alloy. The low-temperature tissue stability should be strictly inspected according to the use temperature. Appropriate heat treatment should be carried out during the processing to ensure that the material has good deep drawing performance. When using forged materials, their airtightness should be strictly inspected.

[0003] With the booming development of industry, the demand for Kovar alloy foils is increasing, and the performance and processing requirements for Kovar alloy foils are also increasing day by day. Currently, the main restrictive factors in the production of Kovar alloy foils are as follows: the gas content in the alloy ingots used for Kovar alloy foil production is high; the inclusions in the alloy ingots used for Kovar alloy foil production are high. Currently, the production of Kovar alloy ingots mainly uses the two-stage method or the three-stage method. The two-stage method is vacuum melting + electroslag remelting, and the three-stage method is vacuum melting + electroslag remelting + consumable electrode remelting. Whether it is the three-stage or the two-stage method, it is to reduce the gas content and inclusions in the Kovar alloy ingots, but the filtering ability of these two processes for inclusions and gases is ultimately limited.

[0004] Therefore, how to reduce the gas content and inclusion grade of the Kovar alloy master electrode is a current research direction. Summary of the Invention

[0005] (I) Object of the Invention

[0006] The object of the present invention is to provide a preparation method of a Kovar alloy master electrode that can reduce the gas content and inclusion grade of the Kovar alloy master electrode.

[0007] (II) Technical Solution

[0008] To solve the above problems, the present invention provides a preparation method of a Kovar alloy master electrode, including:

[0009] Loading raw materials into an electric arc furnace for melting to obtain a first mixture, where the raw materials include iron-nickel-cobalt waste and a first auxiliary material;

[0010] Loading the first mixture into an AOD furnace for blowing to obtain a second mixture;

[0011] Load the second mixture, nickel, iron, cobalt and manganese into a vacuum induction furnace for smelting to obtain a Kovar alloy master electrode.

[0012] On the other hand, preferably, the first auxiliary material includes: aluminum powder and first lime;

[0013] The iron-nickel-cobalt waste, aluminum powder and first lime are in a ratio of 1: 0.5% to 0.7%: 2.5% to 3% based on the furnace charge.

[0014] On the other hand, preferably, 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% to 2% based on the furnace charge, and the mass ratio of the second lime to fluorite is 5: 1 to 4: 1.

[0015] On the other hand, preferably,

[0016] The step of loading the raw materials into an electric arc furnace for smelting to obtain a first mixture includes:

[0017] Load the raw materials into the electric arc furnace and heat them for a first time to obtain a first molten steel;

[0018] Blow oxygen onto the top of the first molten steel and stop blowing oxygen when the iron-nickel-cobalt waste is completely melted;

[0019] Blow argon into the side or bottom of the first molten steel and stir for a second time;

[0020] Let the first molten steel stay at a first temperature for a third time and then tap the furnace to obtain a first mixture.

[0021] On the other hand, 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 °C, the third time is 45 - 65 min, and the tapping conditions include that the temperature reaches 1600 - 1700 °C, and the contents of P and S in the first molten steel are both less than or equal to 0.02%.

[0023] On the other hand, preferably,

[0024] The step of loading the first mixture into an AOD furnace for blowing to obtain a second mixture includes:

[0025] Transport the first mixture to the AOD furnace through a tundish to obtain a second molten steel;

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

[0027] Add an alloy and a first deoxidizer to the second molten steel within a fifth time;

[0028] When the temperature of the second molten steel reaches a second temperature, pour it to obtain a second mixture, and use argon for protection during pouring.

[0029] On the other hand of the present invention, 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 rate 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, the fifth time is 8 - 12 min; the addition amount of the alloy is 5% - 10% of the furnace charge amount of the iron-nickel-cobalt waste; the addition amount of the first deoxidizer is 0.4% - 0.5% of the furnace charge amount of the iron-nickel-cobalt waste;

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

[0034] On the other hand of the present invention, preferably,

[0035] Load the second mixture, nickel, iron, cobalt, and manganese into a vacuum induction furnace for smelting to obtain a Kovar alloy master electrode, including:

[0036] Determine the return ratio of the second mixture, calculate the charging amounts of nickel, iron, cobalt, and manganese according to the return ratio, and weigh the raw materials of the second mixture, nickel, iron, cobalt, and manganese according to the return ratio and the charging amounts;

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

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

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

[0040] Refine the third molten steel;

[0041] Argon is filled into the third molten steel refined to the eighth time. After adding the raw material of manganese, pouring and demolding are carried out to obtain the Kovar alloy mother electrode.

[0042] On the other hand of the present invention, preferably,

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

[0044] The input amounts of nickel, iron, cobalt and manganese are calculated by using the following formula:

[0045] Input amount of nickel = (28.5 - 29.5% - return ratio * percentage content of nickel in the second mixture) * furnace charge;

[0046] Input amount of cobalt = (16.8 - 17.8% - return ratio * percentage content of cobalt in the second mixture) * furnace charge;

[0047] Input amount of manganese = (0.5% - return ratio * percentage content of manganese in the second mixture) * furnace charge;

[0048] Input amount of iron = furnace charge - weight of the second mixture - input amount of nickel - input amount of cobalt - input amount of manganese.

[0049] On the other hand of the present invention, preferably,

[0050] The pretreatment includes:

[0051] Turning or polishing the surface of the second mixture until it is rust-free and oil-free;

[0052] 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 hours;

[0053] 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;

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

[0055] The temperature of the refining is 1530 - 1590 °C. During the refining, a second deoxidizer is added and degassing is carried out;

[0056] The pouring method is top pouring, pouring until the riser is filled with a small stream for feeding, and the pouring temperature is 1520 - 1590 °C;

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

[0058] (III) Beneficial effects

[0059] The above technical solution of the present invention has the following beneficial technical effects:

[0060] The present invention uses the high temperature in the electric arc furnace to oxidize the impurities on the surface of the scrap steel into gas or slag, and forms a basic furnace (CaO~MgO~SiO 2 ), adsorbing inclusions such as silicon oxide and phosphorus oxide. When using an AOD furnace for blowing, oxygen or argon is blown in to promote the aggregation of inclusions and float them to the slag layer, and by adding reducing agents such as ferrosilicon and aluminum powder, part of the oxide inclusions are reduced and deoxidized, reducing the oxygen content, and reducing the gas content and inclusion level of the Kovar alloy mother electrode. The gas content of the Kovar alloy mother electrode of the present invention is below 1.0ppm, and the inclusions are mainly Class D inclusions (fine series) and the level is below 0.5. The Kovar alloy mother electrode produced by the present invention can significantly improve the yield rate of subsequent hot processing due to the low gas content. The Kovar alloy mother electrode produced by the present invention can effectively improve the yield rate of subsequent foil rolling due to the low level of inclusions, and can ensure good surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is an overall flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. 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 invention.

[0063] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, it should be noted that the terms “first”, “second” and “third” are only used 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 invention described below can be combined with each other as long as they do not conflict with each other.

[0066] Example

[0067] A method for preparing a Kovar alloy mother electrode, Figure 1 FIG. 1 shows an overall flow chart of an embodiment of the present invention, as shown in FIG.Figure 1 As shown in the figure, it includes:

[0068] Put the raw materials into an electric arc furnace for smelting to obtain a first mixture. The raw materials include iron-nickel-cobalt waste and a first auxiliary material. The iron-nickel-cobalt waste should be dry without moisture and oil stains, without airtight containers such as gas cylinders. 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 ratio of the iron-nickel-cobalt waste, aluminum powder, and first lime by furnace charge is 1:0.5% - 0.7%:2.5% - 3%. 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 moisture content of the aluminum powder is <1.20%, and Al > 95%. The CaO content in the first lime is >90%, the sulfur content is <0.1%, and the water content of the first lime fed into the furnace is <0.3%. The first auxiliary material also includes fluorite or second lime. The ratio of the iron-nickel-cobalt waste and the second lime by furnace charge is 1:0.5% - 2%, and the mass ratio of the second lime and fluorite is 5:1 - 4:1. When the mixed slag liquid of the iron-nickel-cobalt waste, aluminum powder, and first lime is in a viscous state, fluorite is added. When the mixed slag liquid of the iron-nickel-cobalt waste, aluminum powder, and first lime is in a thick and thin state, second lime is added. The fluorite is required to have a content >85%, SiO 2 <4%, CaO < 5%, S < 0.1%, H 2 O < 0.5%, and it should be dried at a low temperature of 120 - 150 °C for 5 hours before use.

[0069] Furthermore, in this embodiment, the step of putting the raw materials into an electric arc furnace for smelting to obtain a first mixture includes:

[0070] Put the raw materials into the electric arc furnace and heat them for a first period of time to obtain a first molten steel. The first period of time is 15 - 25 min. The charging method of putting the raw materials into the electric arc furnace includes: dense at the bottom, loose at the top, high in the middle, low around, no large materials at the furnace door, fast through the well, no bridging. Bottom filling, fill small materials at the bottom of the charging tank, and the quantity accounts for 50% of the total amount of small materials. Central area filling, fill large materials in the central area at the lower part of the charging tank, including low-carbon waste or refractory furnace materials. Gap filling between large materials, fill medium and small materials in the gaps between large materials. Filling above and around large materials, install medium materials above and around large materials. Top filling, place the remaining small materials at the top position (below the electrode) to ensure that after the electrode is energized, the small materials can be quickly buried in the material through the gas well, reducing the irradiation of the arc light on the boiler furnace cover.

[0071] Blow oxygen onto the top of the first molten steel, and stop blowing oxygen when the iron-nickel-cobalt waste is completely melted; blow argon onto the side or bottom of the first molten steel and stir for a second time; blow oxygen onto the top of the first molten steel to promote the oxidation of impurities on the surface of the scrap steel, generating gas or slag. The blowing of oxygen can also increase the temperature of the molten steel and accelerate the melting of the scrap steel; after stopping the blowing of oxygen, blow argon onto the side or bottom of the first molten steel and stir the first molten steel for a second time to promote the homogenization of components and prevent local overheating. Remove impurities through oxygen oxidation, and promote the homogenization of components through argon stirring. This stage is a low-temperature stage, mainly completing the preliminary melting of the scrap steel and the removal of impurities; further, adopt a pulsed oxygen / argon alternating blowing mode, for example: high-frequency short-pulse oxygen + low-frequency long-pulse argon, oxidize inclusions through instantaneous high-pressure oxygen, and the argon pulse enhances the stirring force of the molten pool and promotes the floating efficiency of inclusions. The oxygen pulse frequency is 5 - 10 Hz, the argon pulse frequency is 1 - 2 Hz, and the volume ratio of the mixed gas is adjusted to oxygen:argon = 1:4 - 1:6, which can further reduce the oxygen content to less than 0.5 ppm.

[0072] After the first molten steel is held at the first temperature for the third time, tap it to obtain a first mixture. The first time is 15 - 25 min, and 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 tapping conditions include that the temperature reaches 1600 - 1700 °C, and the contents of P and S in the first molten steel are both less than or equal to 0.02%. Blow argon and stir the molten steel to promote the floating of inclusions to the slag layer. This stage lasts for 45 - 65 minutes to ensure the uniform composition of the molten steel and the full removal of inclusions.

[0073] The temperature in the electric arc furnace is as high as 3000 °C, and the impurities on the surface of the scrap steel are oxidized into gas or slag through high-temperature oxidation. By adding slag formers such as limestone and fluorite, a basic furnace (CaO - MgO - SiO 2 ) is formed to adsorb inclusions such as silicon oxide and phosphorus oxide. Promote the aggregation of inclusions and their floating to the slag layer through the blowing and stirring of oxygen or argon. Through oxygen oxidation and argon stirring, effectively remove impurities such as phosphorus and sulfur in the molten steel, significantly reduce the contents of P and S (≤0.02%), the basic furnace slag adsorbs inclusions, and the gas blowing and stirring promote the floating of inclusions, further improving the purity.

[0074] Charge the first mixture into an AOD furnace for blowing to obtain a second mixture; including:

[0075] Transfer the first mixture to an AOD furnace through a tundish to obtain a second molten steel; transfer the first mixture from an electric arc furnace to the AOD furnace through the tundish to ensure minimal temperature loss during the transfer process;

[0076] Blow a mixed gas into the second molten steel for a fourth period of time. The mixed gas includes oxygen and argon; the volume ratio of oxygen to argon in the mixed gas is 0.5 - 1.5:8.5 - 9.5; the gas flow rate of the mixed gas is 900 - 1200 NL / h, and the fourth period of time is 30 - 50 min; oxygen is used to oxidize impurities in the molten steel, and argon is used to stir the molten steel. Stirring with argon is beneficial for inclusions to float up and promotes compositional homogenization; by controlling the flow rate and ratio of the mixed gas, the composition of the molten steel is precisely adjusted;

[0077] Add an alloy and a first deoxidizer to the second molten steel within a fifth period of time; the alloy is ferrosilicon, and the first deoxidizer is aluminum powder. The fifth period of time is 8 - 12 min; the addition amount of the alloy is 5% - 10% of the charging amount of the iron-nickel-cobalt waste; the addition amount of the first deoxidizer is 0.4% - 0.5% of the charging amount of the iron-nickel-cobalt waste; when the temperature of the molten steel is too low, ferrosilicon can be added to release heat and increase the temperature of the molten steel; ferrosilicon can also adjust the silicon content of the second molten steel, improve the fluidity and deoxidation effect of the second molten steel. By adding aluminum powder, some oxide inclusions are reduced; further, the first deoxidizer is a nano aluminum-magnesium composite deoxidizer (Al-Mg@C core-shell structure, particle size 50 - 100 nm). The high specific surface area of the nano-particles is used to enhance the deoxidation efficiency and at the same time inhibit secondary oxidation. The addition amount of the nano aluminum-magnesium composite deoxidizer is 0.2% - 0.3% of the charging amount of the iron-nickel-cobalt waste, and the oxygen content can be additionally reduced by 20%. The Al-Mg@C core-shell structure refers to a special structure with an aluminum-magnesium alloy or its mixture as the core and a layer of carbon material wrapped outside.

[0078] When the temperature of the second molten steel reaches a second temperature, pour it to obtain a second mixture. During pouring, argon is used for protection. The second temperature is 1520 °C - 1580 °C, the gas flow rate of the argon is 180 - 300 NL / h, the argon valve is opened 1 min before pouring, and the argon valve is closed after pouring ends.

[0079] Load the second mixture, nickel, iron, cobalt, and manganese into a vacuum induction furnace for melting to obtain a Kovar alloy master electrode, including:

[0080] Determine the return ratio of the second mixture, calculate the input amounts of nickel, iron, cobalt and manganese according to the return ratio, and weigh the raw materials of the second mixture, nickel, iron, cobalt and manganese according to the return ratio and input amounts; wherein, the composition of the Kovar alloy master electrode in this embodiment includes: 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 input amounts of the nickel, iron, cobalt and manganese are calculated using the following formulas:

[0082] Nickel input amount = (28.5 - 29.5% - return ratio * nickel percentage content in the second mixture) * furnace charge;

[0083] Cobalt input amount = (16.8 - 17.8% - return ratio * cobalt percentage content in the second mixture) * furnace charge;

[0084] Manganese input amount = (0.5% - return ratio * manganese percentage content in the second mixture) * furnace charge;

[0085] Iron input amount = furnace charge - weight of the second mixture - nickel input amount - cobalt input amount - manganese input amount.

[0086] Pretreat the raw materials of the second mixture, nickel, iron, cobalt and manganese; the pretreatment includes:

[0087] Turn or polish the surface of the second mixture until it is free of rust and oil;

[0088] Bake the raw material of nickel at 800°C for ≥6h, keep the raw materials of iron and cobalt dry, and bake the raw material of manganese at 80 - 180°C for at least 24 hours;

[0089] The pretreatment of the refractory materials includes: the baking system for the ingot mold and riser is baking at 80 - 180°C for ≥24h, the tundish uses precast refractory materials, and the baking system is 800 - 900°C ≥12h. Strictly control the intermediate process, and non - compliant items will not be executed.

[0090] Load the pretreated raw materials of the second mixture, nickel, iron and cobalt into a vacuum induction furnace; the loading method includes: adding cobalt to the bottom of the crucible, and the remaining second mixture, nickel and iron are loaded into the furnace cross - wise. The general principle of cloth - laying is dense at the bottom and loose at the top;

[0091] Smelting is carried out using a vacuum induction furnace to obtain a third molten steel. The smelting includes: heating to a sixth time at a first melting power at a first vacuum degree and heating to a seventh time at a second melting power at a second vacuum degree using a vacuum induction furnace.

[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; in case of splashing during the melting process, the power should be reduced in time or the power supply should be cut off; the sixth time is 1 - 2 h, and the seventh time is 4 - 6 h.

[0093] The third molten steel is refined; the temperature of the refining is 1530 - 1590 °C. During the refining, a second deoxidizer is added and degassing is carried out; argon is filled into the third molten steel at the eighth time. After adding the raw material of manganese, pouring and demoulding are carried out to obtain a Kovar alloy master electrode. The eighth time is 45 - 60 min, the argon filling is 5000 - 10000 Pa, metallic manganese is added, and stirring is carried out for 10 - 15 min until there are no bubbles on the surface of the molten steel.

[0094] The pouring method is top - pouring. Pour until the riser is filled with a small stream for feeding. The feeding time of the riser is greater than 1 / 2 - 2 / 3 of the feeding time of the ingot body. The pouring temperature is 1520 - 1590 °C. After pouring, the vacuum is quickly broken and a heating agent is added. After the first addition, wait for 10 - 15 min and then add the second heating agent. The composition of the heating agent: 70% industrial aluminum powder and 30% sodium nitrate; the dosage of the heating agent is 0.2 - 0.6% of the weight of the molten steel. The cooling time of the demoulding is greater than or equal to 8 hours. The heating agent prolongs the solidification time of the molten steel in the riser, slows down the temperature drop, continuously generates heat for feeding; improves the shrinkage cavity morphology and feeding efficiency, and enhances the feeding effect; is beneficial for inclusions to float up, purifies the molten steel and improves the quality of the ingot.

[0095] In this embodiment, the high temperature in the electric arc furnace promotes the oxidation of impurities on the surface of the scrap steel into gas or slag. By adding slag - forming agents such as limestone and fluorite, a basic furnace (CaO - MgO - SiO 2), adsorbing inclusions such as silicon oxide and phosphorus oxide. When using an AOD furnace for blowing, oxygen or argon is blown in to promote the aggregation of inclusions and float them to the slag layer, and by adding reducing agents such as ferrosilicon and aluminum powder, part of the oxide inclusions are reduced and deoxidized, reducing the oxygen content, and reducing the gas content and inclusion level of the Kovar alloy mother electrode. The gas content of the Kovar alloy mother electrode of the present invention is below 1.0ppm, and the inclusions are mainly Class D inclusions (fine series) and the level is below 0.5. The Kovar alloy mother electrode produced by the present invention can significantly improve the yield rate of subsequent hot processing due to the low gas content. The Kovar alloy mother electrode produced by the present invention can effectively improve the yield rate of subsequent foil rolling due to the low level of inclusions, and can ensure good surface quality.

[0096] Example 1

[0097] Fe-Ni-Co scrap, aluminum powder and first lime are charged into an electric arc furnace for heating to obtain a first molten steel, wherein the Fe-Ni-Co scrap, aluminum powder and first lime are calculated as 1:0.5%:3% based on the charge; when the first molten steel reaches 2 / 3 of the charge, 1 / 2 of the total amount of the first lime is added, and the remaining first lime is added after full melting; Fe-Ni-Co scrap and second lime are calculated as 1:0.5% based on the charge, and the mass ratio of the second lime to fluorite is 5:1; the timing of adding fluorite and second lime is based on the flow rate of the first molten steel, during the smelting process, the viscosity of the slag is high, that is, the phenomenon of back drying occurs, and a small amount of fluorite is added in batches through the high-level silo to improve the fluidity of the slag until the fluidity is good; the raw materials are charged into an electric arc furnace for heating for 15 minutes, oxygen is blown into the top of the first molten steel, and the blowing of oxygen is stopped when the Fe-Ni-Co scrap is completely melted, argon is blown into the side or bottom of the first molten steel, and stirred for 5 minutes; when the first molten steel is at 1500° C., it is taken out of the furnace to obtain a first mixture. Oxygen flow rate is 1000m 3 / h, argon flow rate is 200m 3 / h, and the conditions for taking out the furnace include that the temperature reaches 1600°C, and the P content and the S content in the first molten steel are both less than or equal to 0.02%.

[0098] transporting the first mixture to an AOD furnace through a tundish to obtain a second molten steel;

[0099] Blow a mixed gas into the second molten steel until the fourth time. The mixed gas includes oxygen and argon. The volume ratio of oxygen to argon in the mixed gas is 0.5:9.5. The gas flow rate of the mixed gas is 900 NL / h. The fourth time is 30 min. Add alloy and the first deoxidizer to the second molten steel. Complete the addition within 8 min. The alloy is ferrosilicon, and the first deoxidizer is aluminum powder. The addition amount of the alloy is 5% of the charged amount of the iron-nickel-cobalt waste. The addition amount of the first deoxidizer is 0.4% of the charged amount of the iron-nickel-cobalt waste. When the temperature of the second molten steel reaches the second temperature, pour. The second temperature is 1520 °C to obtain a second mixture. During pouring, use argon for protection. The gas flow rate of argon is 180 NL / h.

[0100] Batch according to a return ratio of 80%, C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.5%, Co = 16.8%. Pretreat the raw materials of the second mixture, nickel, iron, cobalt, and manganese. Turn the surface of the second mixture smooth until there is no rust and no oil stain. Bake the raw material of nickel at 800 °C for 6 h, keep the raw materials of iron and cobalt dry, and bake the raw material of manganese at 80 °C for 24 h. The baking system for the ingot mold and riser is to bake at 100 °C for 24 h. The tundish uses precast refractory materials, and the baking system is 830 °C for 12 h.

[0101] Load the pretreated raw materials of the second mixture, nickel, iron, cobalt, and manganese into a vacuum induction furnace. When loading, add electrolytic cobalt at the bottom of the crucible, add 1 / 3 of graphite carbon with the furnace, and load the remaining second mixture, electrolytic nickel, and pure iron into the furnace alternately. The general principle of charging is to be dense at the bottom and loose at the top. When the first vacuum degree is 17 pa, start powering on at 80 KW to preheat the materials for 1 h. When the second vacuum degree is 30 pa, the second melting power is 380 KW. If splashing occurs during the melting process, immediately reduce the power or cut off the power. The melting time is 4 h.

[0102] Add graphite carbon for degassing every 5 min. If the carbon addition reaction is intense and the vacuum degree changes greatly, appropriately extend the carbon addition time. The refining temperature is 1530 °C, and the time is 45 min.

[0103] Before tapping, fill the furnace with argon at 5000 pa, add ferromanganese, and stir for 10 min until the steel surface is calm and there are no bubbles. Take composition samples, gas samples, and expansion samples.

[0104] Argon protection casting, casting method: top casting method. A slag dam and a slag stopper are installed in the launder. A φ35 nozzle is used. Pour until the top of the ingot is filled for feeding and compensation. Pouring temperature: 1520 °C. The feeding and compensation time of the top of the ingot is greater than 1 / 2 of the feeding and compensation time of the ingot body. After pouring, quickly break the vacuum and add the heating agent. Wait for 10 minutes after the first addition and then add the second heating agent. Composition of the heating agent: 70% industrial aluminum powder, 30% sodium nitrate; the dosage of the heating agent is 0.2% of the weight of the molten steel. The mold cooling time after tapping is 8 hours. After the ingot is demoulded, it is slowly cooled in a slow cooling pit for 8 hours to obtain the mother electrode ingot.

[0105] Example 2

[0106] Put the iron-nickel-cobalt waste, aluminum powder and the first lime into an electric arc furnace for heating to obtain the first molten steel. The ratio of the iron-nickel-cobalt waste, aluminum powder and the first lime based on the furnace charge is 1:0.7%:2.5%. When the amount of the first molten steel reaches 2 / 3 of the furnace charge, add 1 / 2 of the total amount of the first lime. After complete melting, add the remaining first lime. The ratio of the iron-nickel-cobalt waste and the second lime based on the furnace charge is 1:2%. The mass ratio of the second lime and fluorite is 4:1. The addition time of the fluorite and the second lime is added according to the flow rate of the first molten steel. During the melting process, the viscosity of the furnace slag is relatively high, that is, the phenomenon of slag drying back appears. Add a small amount of fluorite in batches through the high-level bin to improve the fluidity of the slag until the fluidity is good. Put the raw materials into the electric arc furnace and heat for 25 minutes. Blow oxygen to the top of the first molten steel. Stop blowing oxygen when the iron-nickel-cobalt waste is completely melted. Blow argon to the side or bottom of the first molten steel and stir for 15 minutes. When the first molten steel reaches 1600 °C, tap to obtain the first mixture. The oxygen flow rate is 3000 m 3 / h, and the argon flow rate is 500 m 3 / h. The tapping conditions include that the temperature reaches 1700 °C, and the contents of P and S in the first molten steel are both less than or equal to 0.02%.

[0107] Transport the first mixture to the AOD furnace through the tundish to obtain the second molten steel;

[0108] Blow a mixed gas into the second molten steel until the fourth time. The mixed gas includes oxygen and argon; the volume ratio of oxygen to argon in the mixed gas is 1:9, and the gas flow rate of the mixed gas is 1200 NL / h. The fourth time is 50 minutes. Add alloy and the first deoxidizer to the second molten steel; complete the addition within 12 minutes. The alloy is ferrosilicon, and the first deoxidizer is aluminum powder. The addition amount of the alloy is 10% of the furnace charge of the iron-nickel-cobalt waste; the addition amount of the first deoxidizer is 0.5% of the furnace charge of the iron-nickel-cobalt waste. When the temperature of the second molten steel reaches the second temperature, pour. The second temperature is 1580 °C to obtain the second mixture. During pouring, use argon for protection, and the gas flow rate of argon is 300 NL / h.

[0109] Batch the materials according to a return ratio of 60%, C 0.01%, Mn 0.5%, Si 0.3%, Ni = 29.5%, Co = 17.8%; Pretreat the raw materials of the second mixture, nickel, iron, cobalt and manganese. Turn the surface of the second mixture until it is free of rust and oil; Bake the raw material of nickel at 800 °C for 7 h, keep the raw materials of iron and cobalt dry, and bake the raw material of manganese at 180 °C for 24 h; The baking system for the ingot mold and riser is to bake at 180 °C for 24 h. The tundish uses precast refractory materials, and the baking system is 800 °C for 12 h.

[0110] Load the pretreated raw materials of the second mixture, nickel, iron, cobalt and manganese into a vacuum induction furnace; When loading, add electrolytic cobalt to the bottom of the crucible, add 1 / 3 graphite carbon with the furnace, and load the remaining second mixture, electrolytic nickel and pure iron into the furnace alternately. The general principle of cloth loading is dense at the bottom and loose at the top; When the first vacuum degree is 30 Pa, start power supply of 150 KW to preheat the materials for 2 h. When the second vacuum degree is 90 Pa, the second melting power is 450 KW. If splashing occurs during the melting process, reduce the power or cut off the power in time. The melting time is 6 h;

[0111] Add graphite carbon for degassing every 10 min. If the carbon addition reaction is intense and the vacuum degree changes greatly, appropriately extend the carbon addition time. The refining temperature is 1590 °C and the time is 60 min;

[0112] Before tapping, fill the furnace with argon at 10000 Pa, add metallic manganese, and stir for 15 min until the steel liquid surface is calm and no bubbles emerge. Take composition samples, gas samples and expansion samples;

[0113] Pour under argon protection. Pouring method: top pouring method. Install a slag dam and slag stopper in the launder. Use a φ35 nozzle. Pour until the riser is filled with small streams for feeding. Pouring temperature: 1590 °C. The riser feeding time is greater than 1 / 2 of the ingot body feeding time. After pouring, quickly break the vacuum and add the heating agent. Wait for 15 min after the first addition and then add the heating agent for the second time. Composition of the heating agent: 70% industrial aluminum powder, 30% sodium nitrate; The dosage of the heating agent is 0.6% of the weight of the molten steel. The mold cooling time after tapping is 8 h. After the ingot is demolded, it is slowly cooled in a slow cooling pit for 8 h to obtain the mother electrode ingot.

[0114] Example 3

[0115] Charge ferronickel-cobalt waste, aluminum powder, and first lime into an electric arc furnace for heating to obtain first molten steel. The ratio of ferronickel-cobalt waste, aluminum powder, and first lime by charging amount is 1:0.6%:2.7%. When the amount of the first molten steel reaches 2 / 3 of the charging amount, add 1 / 2 of the total amount of the first lime. After complete melting, add the remaining first lime. The ratio of ferronickel-cobalt waste and second lime by charging amount is 1:1.5%. The mass ratio of the second lime and fluorite is 4.5:1. The addition timing of fluorite and the second lime is added according to the flow rate of the first molten steel. During the smelting process, when the slag viscosity is high, that is, the dry-back phenomenon occurs, add a small amount of fluorite in batches through a high-level bin to improve the fluidity of the slag until the fluidity is good. Charge the raw materials into the electric arc furnace and heat for 20 min. Blow oxygen onto the top of the first molten steel. Stop blowing oxygen when the ferronickel-cobalt waste is completely melted. Blow argon onto the side or bottom of the first molten steel and stir for 10 min. When the first molten steel is at 1550 °C, tap the furnace to obtain a first mixture. The oxygen flow rate is 2000 m 3 / h, and the argon flow rate is 400 m 3 / h. The tapping 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] Transport the first mixture to an AOD furnace through a tundish to obtain second molten steel;

[0117] Blow a mixed gas onto the second molten steel for a fourth time. The mixed gas includes oxygen and argon. The volume ratio of oxygen to argon in the mixed gas is 1:9.5, and the gas flow rate of the mixed gas is 1000 NL / h. The fourth time is 40 min. Add alloy and a first deoxidizer to the second molten steel. Complete the addition within 10 min. The alloy is ferrosilicon, and the first deoxidizer is aluminum powder. The addition amount of the alloy is 8% of the charging amount of the ferronickel-cobalt waste. The addition amount of the first deoxidizer is 0.45% of the charging amount of the ferronickel-cobalt waste. When the temperature of the second molten steel reaches a second temperature, pour. The second temperature is 1560 °C to obtain a second mixture. Protect with argon during pouring, and the gas flow rate of argon is 200 NL / h.

[0118] Batch according to a return ratio of 40%, C 0.01%, Mn 0.5%, Si 0.3%, Ni = 29%, Co = 17%. Pretreat the raw materials of the second mixture, nickel, iron, cobalt, and manganese. Turn the surface of the second mixture smooth until there is no rust and no oil stain. Bake the raw material of nickel at 800 °C for 7 h, keep the raw materials of iron and cobalt dry, and bake the raw material of manganese at 150 °C for 24 h. The baking system for the ingot mold and riser is to bake at 150 °C for 24 h. The tundish uses prefabricated refractory materials, and the baking system is 800 °C for 12 h.

[0119] Load the pre-treated second mixture, raw materials of nickel, iron, cobalt and manganese into a vacuum induction furnace; add electrolytic cobalt at the bottom of the crucible during loading, add 1 / 3 of graphite carbon with the furnace, and load the remaining second mixture, electrolytic nickel and pure iron into the furnace alternately. The general principle of cloth loading is dense at the bottom and loose at the top; when the first vacuum degree is 25 Pa, start power supply of 120 KW to preheat the materials for 1.5 h. When the second vacuum degree is 60 Pa, the second melting power is 400 KW. If splashing occurs during the melting process, reduce the power or cut off the power in time. The melting time is 5 h;

[0120] Add graphite carbon for degassing every 8 min. If the reaction of adding carbon is intense and the change of vacuum degree is large, appropriately extend the carbon addition time. The refining temperature is 1550 °C and the time is 50 min;

[0121] Before tapping, fill the furnace with argon at 8000 Pa, add metallic manganese, and stir for 12 min until the steel liquid surface is calm without bubbles emerging. Take composition samples, gas samples and expansion samples;

[0122] Pour under argon protection. Pouring method: top pouring method. Install a slag dam and a slag stopper in the launder, use a φ35 nozzle, pour until the riser is filled for feeding, pouring temperature: 1550 °C, and the riser feeding time is greater than 1 / 2 of the ingot body feeding time. After pouring, quickly break the vacuum and add a heating agent. Wait for 12 min after the first addition and then add the second heating agent. Composition of the heating agent: 70% industrial aluminum powder, 30% sodium nitrate; the dosage of the heating agent is 0.4% of the weight of the molten steel. The mold cooling time after tapping is 8 h. After the steel ingot is demoulded, it is slowly cooled in a slow cooling pit for 8 h to obtain the mother electrode ingot.

[0123] Example 4

[0124] Load iron-nickel-cobalt waste, aluminum powder and the first lime into an electric arc furnace for heating to obtain the first molten steel. The ratio of iron-nickel-cobalt waste, aluminum powder and the first lime based on the furnace charge is 1:0.55%:2.9%; when the amount of the first molten steel reaches 2 / 3 of the furnace charge, add 1 / 2 of the total amount of the first lime. After complete melting, add the remaining first lime; the ratio of iron-nickel-cobalt waste to the second lime based on the furnace charge is 1:1.7%, and the mass ratio of the second lime to fluorite is 4.6:1; the addition time of fluorite and the second lime is added according to the flow rate of the first molten steel. During the smelting process, when the viscosity of the furnace slag is relatively high, that is, the phenomenon of dry return occurs, add a small amount of fluorite in batches through the high-level bunker to improve the fluidity of the slag until the fluidity is good; load the raw materials into the electric arc furnace and heat for 22 min, blow oxygen to the top of the first molten steel, stop blowing oxygen when the iron-nickel-cobalt waste is completely melted, blow argon to the side or bottom of the first molten steel, and stir for 12 min; when the first molten steel is at 1540 °C, tap to obtain the first mixture. The oxygen flow rate is 2200 m 3 / h, and the argon flow rate is 350 m 3 / h, the tapping conditions include that the temperature reaches 1640 °C, and the contents of P and S in the first molten steel are both less than or equal to 0.02%.

[0125] Transport the first mixture to the AOD furnace through the tundish to obtain the second molten steel;

[0126] Blow a mixed gas into the second molten steel for a fourth time. The mixed gas includes oxygen and argon; the volume ratio of oxygen to argon in the mixed gas is 1:9.2, the gas flow rate of the mixed gas is 1100 NL / h, and the fourth time is 45 min; Add alloy and the first deoxidizer to the second molten steel; complete the addition within 10 min. The alloy is ferrosilicon, and the first deoxidizer is aluminum powder. The addition amount of the alloy is 6% of the charging amount of the iron-nickel-cobalt waste; the addition amount of the first deoxidizer is 0.43% of the charging amount of the iron-nickel-cobalt waste; When the temperature of the second molten steel reaches the second temperature, pour. The second temperature is 1530 °C to obtain the second mixture. Argon is used for protection during pouring, and the gas flow rate of argon is 250 NL / h.

[0127] Batch according to a return ratio of 20%, C 0.01%, Mn 0.5%, Si 0.3%, Ni = 28.8%, Co = 17.1%; Pretreat the raw materials of the second mixture, nickel, iron, cobalt, and manganese. Turn the surface of the second mixture smooth until there is no rust and no oil stain; Bake the raw material of nickel at 800 °C for 7 h, keep the raw materials of iron and cobalt dry, and bake the raw material of manganese at 120 °C for 24 hours; The baking system for the ingot mold and riser is to bake at 120 °C for 24 h. The tundish uses precast refractory materials, and the baking system is 800 °C for 12 h.

[0128] Load the pretreated second mixture, and the raw materials of nickel, iron, cobalt, and manganese into the vacuum induction furnace; When loading, add electrolytic cobalt at the bottom of the crucible, add 1 / 3 graphite carbon with the furnace, and load the remaining second mixture, electrolytic nickel, and pure iron into the furnace alternately. The general principle of charging is dense at the bottom and loose at the top; When the first vacuum degree is 27 pa, start powering on at 110 KW to preheat the materials for 1.3 h. When the second vacuum degree is 70 pa, the second melting power is 420 KW. If splashing occurs during the melting process, reduce the power or cut off the power in time. The melting time is 5.5 h;

[0129] Add graphite carbon for degassing every 9 min. If the carbon addition reaction is intense and the vacuum degree changes greatly, appropriately extend the carbon addition time. The refining temperature is 1560 °C and the time is 1 hour;

[0130] Before tapping, fill the furnace with argon at 7000 pa, add ferromanganese, and stir for 13 min until the steel liquid surface is calm without bubbles emerging. Take component samples, gas samples, and expansion samples;

[0131] Argon protection pouring, pouring method: top pouring method, slag dam and slag retaining rod are installed in the flow channel, φ35 nozzle is used, pouring to the cap mouth small flow to compensate for shrinkage, pouring temperature: 1550℃, the cap mouth compensation time is greater than 1 / 2 of the ingot body compensation time. After pouring, quickly break the vacuum and add the heating agent, wait 12 minutes after the first addition to add the second heating agent. The composition of the heating agent: industrial aluminum powder 70%, sodium nitrate 30%; the amount of heating agent is 0.5% of the weight of the molten steel; the mold cooling time after leaving the furnace is 8h, and the mother electrode ingot is obtained after the steel ingot is demolded and slowly cooled in the slow cooling pit for 8h.

[0132] Comparative Example

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

[0134] Use medium frequency furnace for smelting. Preparation before smelting: keep the surface of remelting material dry and free of foreign matter. Other materials such as oil, water stains, cutting fluid, etc. should be baked at 80-200℃ for ≥5h before remelting in the furnace. Deoxidizer, alloy material, heating agent and refractory material should be baked at 50-300℃ for ≥2h. Ingot mold temperature: 50-200℃.

[0135] Melting period: load the returned steel into the crucible in order of size, tighten the bottom and loosen the top to prevent bridging; send power at high power, slowly add lime when the material is melted and see the molten steel, the lime requirements are: 5-50mm (particle size), ≥800℃ bake for more than 24 hours, take out of the heating furnace for standby before use, the amount of lime added: the amount charged in the furnace x1.0-5.0%; measure the temperature after the material is melted, adjust to the refining temperature of 1550-1600℃, and enter the refining period.

[0136] Refining period: During the refining process, argon blowing operation is performed, and slag making begins. The total amount of slag making for a single time is: furnace charge*1.0~3.0%; fluorite 10~60mm (particle size), baked at 50~250℃ for ≥4 hours, and taken out of the heating furnace for standby before use; slag adjustment, lime accounts for 80% of the slag material, and the weight is guaranteed. The amount of fluorite added is adjusted appropriately according to the fluidity of the slag; after the slag has good fluidity, it is initially deoxidized, and deoxidizer A1-Ca0 is added. The single dosage is: furnace charge*0.4%. The slag should be tapped lightly and quickly during the tapping process to prevent aluminum penetration; after the slag is grayish white, the slag is removed for the first time, and slag is made and deoxidized again, and the white slag is kept for 60 minutes.

[0137] Pouring: Add silicon calcium and nickel magnesium alloy into the furnace, take component samples, measure the temperature before taking out of the furnace, and add sponge titanium into the bag; steel tapping temperature: 1610-1650℃, calming time: 2 minutes to 4 minutes and 30 seconds; demoulding time ≥6h.

[0138] Comparative Example 1

[0139] Using the above-mentioned returned material, the return ratio is 0, and the ingredients are prepared according to C0.01%, Mn0.35%, Si0.3%, Ni=28.8%, Co=17.1%. The remaining steps are the same as Example 4.

[0140] Comparative Example 2

[0141] Using the above-mentioned return material, with a return ratio of 60%, charge the materials according to C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.8%, Co = 17.1%, and the remaining steps are the same as those in Example 2.

[0142] Comparative Example 3

[0143] Using the above-mentioned return material, with a return ratio of 40%, charge the materials according to C 0.01%, Mn 0.35%, Si 0.3%, Ni = 28.8%, Co = 17.1%, and the remaining steps are the same as those in Example 3.

[0144] For the Kovar alloy master electrodes produced by this process, measure the gas content and inclusions of Examples 1-4 and Comparative Examples 1-3. Table 1 shows the gas content of Examples 1-4 and Comparative Examples 1-3. As shown in Table 1, the specific detected values of the gas content are as follows:

[0145] Table 1 Measured values 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 N content is 0.5975 ppm, and the H content is 0.06 ppm. The average O content in Comparative Examples 1-3 is 15.82 ppm, the N content is 5.313 ppm, and the H content is 1.51 ppm.

[0148] Table 2 shows the inclusion content of Examples 1-4 and Comparative Examples 1-3. As shown in Table 1, the specific detected values of the inclusion content are as follows:

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

[0150]

[0151]

[0152] In Examples 1-4, it is mainly D-type inclusions (spherical oxide type). According to the standard of GB / T 10561-2005 "Microscopic Examination Method for Determination of Standard Rating Chart of Non-Metallic Inclusion Content in Steel", 0.5 level corresponding to D-type inclusions means that there is 1 inclusion on the detection surface, 1.0 level means that there are 4 inclusions, and 1.5 level means that there are 9 inclusions; in Comparative Examples 1-3, there are B-type (oxide type) and D-type (spherical oxide type) inclusions, with more types and higher levels of inclusions.

[0153] In summary, the Kovar alloy ingots produced by this embodiment have the characteristics of high purity. Due to their advantages of low oxygen content and low inclusions, they can provide high-quality ingots for the subsequent processing of Kovar alloy.

[0154] It should be understood that the above specific embodiments of the present invention are only used for illustrative explanation or interpretation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundary of the appended claims, or equivalent forms of such scope and boundary.

[0155] The present invention has been described above with reference to the embodiments of the present invention. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

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

[0157] Obviously, the above embodiments are only examples for clear illustration and not limitations to the embodiments. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. And the obvious changes or alterations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing a Kovar alloy mother electrode, characterized in that: include: Loading raw materials into an electric arc furnace for smelting to obtain a first mixture, wherein the raw materials include iron-nickel-cobalt waste and a first auxiliary material; The first mixture is charged into an AOD furnace for blowing to obtain a second mixture; The second mixture, nickel, iron, cobalt and manganese are placed in a vacuum induction furnace for smelting to obtain a Kovar alloy mother electrode.

2. The method for preparing a Kovar alloy mother electrode according to claim 1, characterized in that: The first auxiliary material includes: aluminum powder and first lime; The iron-nickel-cobalt waste, aluminum powder and first lime are calculated by furnace loading amount = 1: 0.5%-0.7%: 2.5%-3%.

3. The method for preparing a Kovar alloy mother electrode according to claim 2, characterized in that: The first auxiliary material also includes fluorite or second lime; the iron-nickel-cobalt waste and the second lime are calculated by the furnace loading amount = 1:0.5% to 2%, and the mass ratio of the second lime to fluorite is 5:1 to 4:

1.

4. The method for preparing a Kovar alloy mother electrode according to claim 1, characterized in that: The step of charging the raw materials into an electric arc furnace for smelting to obtain a first mixture comprises: The raw materials are placed in an electric arc furnace and heated for a first time to obtain a first molten steel; Blowing oxygen into the top of the first molten steel, and stopping blowing oxygen when the iron-nickel-cobalt waste is completely melted; Blowing argon gas into the side or bottom of the first molten steel and stirring for a second time; The first molten steel is kept at the first temperature for a third time and then taken out of the furnace to obtain a first mixture.

5. The method for preparing a Kovar alloy mother electrode according to claim 4, characterized in that: The first time is 15 to 25 minutes, the second time is 5 to 15 minutes; the oxygen flow rate is 1000 to 3000 m 3 / h, the argon flow rate is 200 to 500 m 3 / h, the first temperature is 1500 to 1600°C, and the third time is 45 to 65 minutes. The conditions for taking out the furnace include the temperature reaching 1600 to 1700°C, and the P content and S content in the first molten steel are both less than or equal to 0.02%.

6. The method for preparing a Kovar alloy mother electrode according to claim 1, characterized in that: The step of charging the first mixture into an AOD furnace for blowing to obtain a second mixture comprises: transporting the first mixture to an AOD furnace through a tundish to obtain a second molten steel; Blowing a mixed gas into the second molten steel for a fourth time, wherein the mixed gas includes oxygen and argon; adding an alloy and a first deoxidizer to the second molten steel within a fifth time; When the temperature of the second molten steel reaches the second temperature, it is poured to obtain a second mixture, and argon gas is used for protection during pouring.

7. The method for preparing a Kovar alloy mother electrode according to claim 6, characterized in that: The volume ratio of oxygen to argon in the mixed gas is 0.5-1.5:8.5-9.5; The gas flow rate 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, the fifth time is 8 to 12 minutes; the amount of the alloy added is 5% to 10% of the amount of the iron-nickel-cobalt waste charged to the furnace; the amount of the first deoxidizer added is 0.4% to 0.5% of the amount of the iron-nickel-cobalt waste charged to the furnace; The second temperature is 1520° C. to 1580° C., and the gas flow rate of the argon gas is 180 to 300 NL / h.

8. The method for preparing a Kovar alloy mother electrode according to claim 1, characterized in that: The second mixture, nickel, iron, cobalt and manganese are charged into a vacuum induction furnace for smelting to obtain a Kovar alloy mother electrode, comprising: Determine the return ratio of the second mixture, calculate the amount of nickel, iron, cobalt and manganese added according to the return ratio, and weigh the second mixture, nickel, iron, cobalt and manganese raw materials according to the return ratio and the amount of addition; pretreating the second mixture, the raw materials of nickel, iron, cobalt and manganese; charging the pretreated second mixture, the raw materials of nickel, iron and cobalt into a vacuum induction furnace; Using a vacuum induction furnace to perform smelting to obtain a third molten steel, the smelting comprising: heating at a first vacuum degree using a first melting power for a sixth time, and heating at a second vacuum degree using a second melting power for a seventh time; Refining the third molten steel; Argon gas is filled into the third molten steel after being refined for the eighth time, and manganese raw materials are added, followed by casting and demoulding to obtain a Kovar alloy mother electrode.

9. The method for preparing a Kovar alloy mother electrode according to claim 8, characterized in that: The return ratio is: 0<return ratio≤80%; The amounts of nickel, iron, cobalt and manganese added are calculated using the following formula: Nickel addition amount = (28.5-29.5% - return ratio * nickel percentage in the second mixture) * furnace loading amount; Cobalt addition amount = (16.8-17.8% - return ratio * cobalt percentage in the second mixture) * furnace loading amount; Manganese addition amount = (0.5% - return ratio * manganese percentage in the second mixture) * furnace loading amount; Iron addition amount = furnace charge amount - second mixture weight - nickel addition amount - cobalt addition amount - manganese addition amount.

10. The method for preparing a Kovar alloy mother electrode according to claim 8, characterized in that: The pre-processing comprises: Lashing or polishing the surface of the second mixture until it is free of rust and oil stains; The nickel raw material is baked at 800° C. for ≥6 hours, the iron and cobalt raw materials are kept dry, and the manganese raw material is baked at a temperature of 80-180° C. for at least 24 hours; 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 to 2 hours, the seventh time is 4 to 6 hours, and the eighth time is 45 to 60 minutes; The refining temperature is 1530-1590°C, and a second deoxidizer is added during the refining to perform degassing; The pouring method is top pouring, pouring to the cap mouth with small flow to compensate for shrinkage, pouring temperature: 1520~1590℃; The demoulding cooling time is greater than or equal to 8 hours.

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