Iron-based nickel-chromium alloy smelting method

Abstract

The invention relates to an iron-based nickel-chromium alloy smelting method, and belongs to the technical field of iron-based nickel-chromium alloy smelting. The method is vacuum smelting and comprises the following steps: obtaining first alloy liquid containing iron, nickel and chromium; obtaining the theoretical weight of carbon according to the oxygen content of the first alloy liquid; carbon with the theoretical weight is added into the first alloy liquid for a carbon-oxygen reaction, and second alloy liquid is obtained; carbon dioxide is added into the second alloy liquid for decarburization reaction, and third alloy liquid with the first preset carbon content is obtained; under the first preset technological parameters, carbon dioxide is added into the third alloy liquid, the third alloy liquid is subjected to impurity removal treatment through the bubble vacuum chamber effect of the carbon dioxide, and fourth alloy liquid with the second preset carbon content is obtained; and under second preset technological parameters, argon is added into the fourth alloy liquid to be subjected to a carbon-silicon-oxygen reaction with the silicon-based material, and first iron-based nickel-chromium alloy liquid is obtained. The invention provides a feasible method for cooperatively controlling deoxidation and crucible oxygen decomposition through different carbon-oxygen reaction stages.

Description

Technical Field

[0001] The present application relates to the technical field of iron-based nickel-chromium alloy smelting, and in particular to a method for smelting an iron-based nickel-chromium alloy. Background Art

[0002] Ultra-pure ultra-low carbon oxygen aluminum iron-based nickel-chromium alloy is widely used in semiconductors and 5G materials. On the basis of iron-based nickel-chromium alloy, impurities and harmful elements are removed to make it purer and achieve extremely high corrosion resistance and mechanical properties. Especially the carbon, oxygen content and impurity element content are demanding. The carbon content is generally required to be less than 0.006%, the aluminum content is less than 0.001%, the oxygen content is less than 10ppm, or even less than 2ppm, and the D-type inclusions are required to be less than 0.5 level. Therefore, the problems of ultra-low content control of oxygen, C, and impurity elements in the vacuum smelting process and coordinated control of crucible decomposition need to be solved urgently. Oxygen, as a residual element in molten steel, will greatly reduce the various properties of steel. For example, for ultra-pure stainless steel, in order to meet the requirements of steel for corrosion resistance and mechanical properties, the oxygen in the steel must be controlled below 0.0010%; in high-temperature alloys, oxides are usually the initiation and expansion channel of fatigue cracks, thereby affecting the creep, endurance strength and other properties of high-temperature alloys. Therefore, deoxidation is a key link in vacuum smelting.

[0003] At present, vacuum induction carbon deoxidation is the dominant method in vacuum induction smelting. In order to achieve ultra-low carbon, nitrogen, oxygen, aluminum, and ultra-low inclusion levels, the vacuum degree is often increased, the vacuum chamber pressure is reduced, and the smelting time is extended. However, the MgO crucible decomposes faster under high temperature and high vacuum. At present, as a mature refractory material for large-scale industrial production, the ultra-low control of oxygen content in the production and preparation of ultra-pure, ultra-low carbon oxygen aluminum iron-based nickel-chromium alloys under high temperature and high vacuum has become a bottleneck. There are currently no successful cases of industrial development at home and abroad. Summary of the invention

[0004] The present application provides a method for smelting an iron-based nickel-chromium alloy to solve the following technical problem: how to reduce the carbon and oxygen content of the iron-based nickel-chromium alloy.

[0005] In a first aspect, the present application provides a method for smelting an iron-based nickel-chromium alloy, the method being vacuum smelting, the method comprising:

[0006] Obtaining a first alloy liquid containing iron, nickel and chromium;

[0007] Obtaining a theoretical weight of carbon according to the oxygen content of the first alloy liquid;

[0008] Adding the carbon having a theoretical weight into the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid;

[0009] adding carbon dioxide to the second alloy liquid to perform a decarburization reaction to obtain a third alloy liquid containing a first preset carbon content;

[0010] Under the first preset process parameters, adding carbon dioxide to the third alloy liquid so that bubbles of the carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content;

[0011] Under the second preset process parameters, argon gas is added to the fourth alloy liquid to carry out a carbon-silicon-oxygen reaction with the silicon-based material to obtain a first iron-based nickel-chromium alloy liquid.

[0012] Optionally, the theoretical weight of the carbon satisfies the following relationship:

[0013] 0.15%+1.2×a

[0014] Wherein, a represents the oxygen content of the first alloy liquid, in ppm.

[0015] Optionally, the process parameters of the carbon-oxygen reaction include: a temperature of 1600° C. to 1640° C. and a vacuum degree of 0.1 Pa to 5 Pa.

[0016] Optionally, in the decarbonization reaction, the flow rate of carbon dioxide is 1000 Nm 3 / h~3000Nm 3 / h, the adding time of carbon dioxide is (5~10)×T min, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0017] Optionally, the first preset carbon content is ≤0.015%.

[0018] Optionally, the first preset process parameters include: temperature of 1570° C. to 1600° C., vacuum degree of 1 Pa to 5 Pa; and / or,

[0019] During the impurity removal process, the flow rate of carbon dioxide is 500 Nm 3 / h~1500Nm 3 / h, the adding time of carbon dioxide is (3~6)×T min, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0020] Optionally, the second preset carbon content is ≤ 00.01%.

[0021] Optionally, the second preset process parameters include: a temperature of 1550° C. to 1570° C., a vacuum degree of 5 Pa to 10 Pa; and / or,

[0022] In the carbon-silicon-oxygen reaction, the flow rate of argon is 2000 Nm 3 / h~4000Nm3 / h, the argon addition time is (4~9)×Tmin, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0023] Optionally, after adding argon gas to the fourth alloy liquid under the second preset process parameters to react with the silicon-based material to carry out a carbon-silicon-oxygen reaction to obtain a first iron-based nickel-chromium alloy liquid, the process further includes:

[0024] In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of the argon gas is 1000Pa~4000Pa, the standing time is (2~5)×(H / 1.2)min, and H represents the height of the container containing the first iron-based nickel-chromium alloy liquid.

[0025] Optionally, the chemical composition of the target iron-based nickel-chromium alloy liquid includes, by mass fraction: C<0.006%, Al<0.001%, 10%≤Cr≤30%, 10%≤Ni≤20%, Si<0.15%, Mn<0.05%, [O]<10ppm, N<5ppm, and Fe;

[0026] The D-type inclusions in the target iron-based nickel-chromium alloy liquid are below level 0.5.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The method for smelting the iron-based nickel-chromium alloy provided in an embodiment of the present application is vacuum smelting, and the method includes: obtaining a first alloy liquid containing iron, nickel and chromium; obtaining a theoretical weight of carbon according to the oxygen content of the first alloy liquid; adding the carbon with a theoretical weight to the first alloy liquid for carbon-oxygen reaction to obtain a second alloy liquid; adding carbon dioxide to the second alloy liquid for decarburization reaction to obtain a third alloy liquid containing a first preset carbon content; adding carbon dioxide to the third alloy liquid under first preset process parameters so that the bubbles of the carbon dioxide produce a vacuum chamber effect to decontaminate the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content; adding argon gas to the fourth alloy liquid under second preset process parameters to react with a silicon-based material for carbon-silicon-oxygen reaction to obtain a first iron-based nickel-chromium alloy liquid. According to the oxygen content of the first alloy liquid containing iron, nickel and chromium to obtain the theoretical weight of carbon, the first alloy liquid reacts with the carbon with the theoretical weight to generate gas CO, thereby removing oxygen from the first alloy liquid; the second alloy liquid has abundant carbon and reacts with carbon dioxide to generate gas CO, thereby removing carbon from the second alloy liquid to a large extent; under the first preset process parameters, the vacuum chamber effect generated by the bubbles of carbon dioxide is used to remove impurities from the third alloy liquid, thereby achieving the effect of ultra-low carbon, nitrogen, oxygen and ultra-low inclusion level, and smelting under the first preset process parameters can inhibit the generation of decomposed oxygen in the container containing the alloy liquid; under the second preset process parameters, argon is added to the fourth alloy liquid containing the second preset carbon content to react with silicon-based materials to generate gas CO and SiO, thereby removing carbon and oxygen from the fourth alloy liquid, and smelting under the second preset process parameters can further inhibit the generation of decomposed oxygen in the container (generally MgO refractory crucible) containing the alloy liquid, thereby reducing the carbon and oxygen content of the iron-based nickel-chromium alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1 A schematic flow chart of a method for smelting an iron-based nickel-chromium alloy provided in an embodiment of the present application;

[0032] Figure 2A graph showing the relationship between the decomposition equilibrium oxygen [O], vacuum degree and temperature of the magnesium oxide crucible provided in an embodiment of the present application;

[0033] Figure 3 This is a carbon-oxygen balance diagram of the alloy liquid provided in the embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0036] In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of the present application, the terms "include", "comprise", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0038] In a first aspect, the present application provides a method for smelting an iron-based nickel-chromium alloy, wherein the method is vacuum smelting. Figure 1A schematic diagram of a process for smelting an iron-based nickel-chromium alloy provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0039] S1, obtaining a first alloy liquid containing iron, nickel and chromium;

[0040] Melting chromium and nickel and performing vacuum deoxidation to obtain a first alloy liquid;

[0041] In the embodiment of the present application, the method of smelting iron-based nickel-chromium alloy is realized by vacuum smelting, which can be vacuum induction smelting, which is a smelting method that uses the principle of electromagnetic induction to heat and melt metal raw materials under vacuum environment; by setting an induction coil around the crucible, when an alternating current passes through the coil, an induced current will be generated in the metal raw material in the crucible. Due to the resistance characteristics of the metal, the induced current will cause the metal to heat up, thereby achieving the purpose of melting and refining the metal. In step S1, iron, nickel and chromium are melted and vacuum deoxidized to obtain a first alloy liquid; wherein, the melting temperature can be 1540-1580°C, and the terminal vacuum degree of vacuum deoxidation can be below 10Pa, so as to achieve the preliminary removal of oxygen from the smelting raw materials and their environment, which can generally be oxygen in a vacuum chamber and raw materials. In addition, the above-mentioned iron, nickel and chromium are of high purity quality, with a purity of more than 99.9%.

[0042] S2. Obtaining a theoretical weight of carbon according to the oxygen content of the first alloy liquid;

[0043] S3, adding the carbon having a theoretical weight into the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid;

[0044] In some embodiments, the process parameters of the carbon-oxygen reaction include: a temperature of 1600° C. to 1640° C. and a vacuum degree of 0.1 Pa to 5 Pa.

[0045] In some embodiments, the theoretical weight of the carbon satisfies the following relationship:

[0046] 0.15%+1.2×a

[0047] Wherein, a represents the oxygen content of the first alloy liquid, in ppm.

[0048] In the embodiment of the present application, according to the oxygen content a of the first alloy liquid, the theoretical weight of carbon is set to 0.15% + 1.2 × a, indicating that the theoretical weight of the carbon is excessive, and after fully removing the oxygen in the first alloy liquid and its environment, the carbon content in the second alloy liquid can be higher than 0.15%. The temperature of the carbon-oxygen reaction can be 1600°C to 1640°C, and the vacuum degree can be 0.1Pa to 5Pa, so as to fully remove the oxygen in the first alloy liquid and its environment. Exemplarily, the temperature of the carbon-oxygen reaction can be 1600°C, 1610°C, 1620°C, 1630°C, 1640°C, etc.; the vacuum degree can be 0.1Pa, 0.2Pa, 0.3Pa, 0.4Pa, 0.5Pa, 1Pa, .2Pa, 3Pa, 4Pa, 5Pa, etc. In addition, the time of the carbon-oxygen reaction is 10min to 30min.

[0049] S4, adding carbon dioxide to the second alloy liquid to perform a decarburization reaction to obtain a third alloy liquid containing a first preset carbon content;

[0050] In some embodiments, in the decarbonization reaction, the flow rate of carbon dioxide is 1000Nm 3 / h~3000Nm 3 / h, the adding time of carbon dioxide is (5~10)×T min, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0051] In an embodiment of the present application, the second alloy liquid undergoes a decarburization reaction with carbon dioxide, and the dissolved carbon in the second alloy liquid reacts with CO2 to generate CO, that is, C+CO2→CO. CO2 has low oxidizing properties and does not react with other elements in the second alloy liquid. The carbon content in the second alloy liquid is higher than 0.15%, and it has a relatively high decarburization rate; the carbon content is high, and the rate-limiting link is the mass transfer of oxygen in the alloy liquid. At this stage, the oxygen transferred by the MgO crucible can be quickly consumed by carbon, and the carbon-oxygen reaction rate is high. Therefore, setting a high temperature and a high vacuum, and adding CO2 after removing the oxygen from the first alloy liquid can enhance the decarburization and deoxidation rate. In this decarburization reaction, the flow rate of carbon dioxide can be 1000Nm 3 / h~3000Nm 3 / h, the addition time of carbon dioxide can be (5-10)×T min, so as to achieve sufficient CO2 supply. For example, the flow rate of carbon dioxide can be 1000Nm 3 / h、1200Nm 3 / h、1400Nm 3 / h、1600Nm 3 / h、1800Nm 3 / h、2000Nm 3 / h、2200Nm 3 / h、2400Nm 3 / h、2600Nm 3 / h、2800Nm 3 / h、3000Nm 3 / h, etc.; the addition time of carbon dioxide can be 5T min, 6T min, 7T min, 8T min, 9T min, 10T min, etc.

[0052] S5. Adding carbon dioxide to the third alloy liquid under the first preset process parameters so that bubbles of the carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content;

[0053] In some embodiments, the first predetermined carbon content is ≤ 0.015%.

[0054] In some embodiments, the first preset process parameters include: a temperature of 1570° C. to 1600° C., a vacuum degree of 1 Pa to 5 Pa; and / or,

[0055] During the impurity removal process, the flow rate of carbon dioxide is 500 Nm 3 / h~1500Nm 3 / h, the adding time of carbon dioxide is (3~6)×T min, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0056] In the embodiment of the present application, generally speaking, the crucible is made of magnesium oxide, and the crucible is arranged in a vacuum chamber. The magnesium oxide (MgO) crucible is easily decomposed to produce oxygen during vacuum smelting. Figure 2 This is a graph showing the relationship between the decomposition equilibrium oxygen [O] of the magnesium oxide crucible provided in the embodiment of the present application and the vacuum degree and temperature; see Figure 2 ; and formula (1) This reaction is the principle of refractory decomposition, which aims to illustrate that lowering the temperature and increasing the vacuum chamber pressure can inhibit the decomposition of the MgO crucible. Figure 2 Combined with the analysis of formula (1), it can be seen that at 1600°C and a pressure of 70Pa, the crucible decomposition equilibrium oxygen is 10PPm. As the pressure decreases or the temperature increases, the equilibrium oxygen rises rapidly. The temperature decrease and the pressure increase are conducive to inhibiting the generation of crucible decomposition oxygen.

[0057] MgO=Mg (g) +[O]

[0058] △G 0 =621 984-208.12T (J / mol) Formula (1)

[0059] The first preset carbon content is ≤0.015%, indicating that the carbon content in the third alloy liquid is relatively low. Figure 3 This is a carbon-oxygen balance diagram of the alloy liquid provided in the embodiment of the present application; please refer to Figure 3 The horizontal axis represents the carbon content of the alloy liquid, and the vertical axis represents the oxygen content of the alloy liquid. Figure 3 It can be seen that when the pressure is lower than 10Pa, the carbon content of the third alloy liquid is ≤0.015%, the equilibrium oxygen concentration increases rapidly, and the carbon-oxygen reaction rate decreases. At this time, the mass transfer of carbon in the third alloy liquid is the rate-limiting link, and the oxygen decomposed in the crucible cannot be consumed in time, resulting in a continuous increase in the oxygen content of the third alloy liquid. The first preset process parameters include: the temperature can be 1570℃~1600℃, the vacuum degree can be 1Pa~5Pa, so as to inhibit the decomposition of the crucible under low temperature and high pressure, and the flow rate of the added carbon dioxide can be 500Nm 3 / h~1500Nm 3 / h, the addition time of carbon dioxide can be (3~6)×Tmin, so as to make full use of the vacuum chamber effect of CO2 bubbles, so that the fourth alloy liquid can achieve ultra-low carbon, nitrogen, oxygen, and ultra-low inclusion level smelting effect. Exemplarily, in the first preset process parameters, the temperature is 1570℃, 1580℃, 1590℃, 1600℃, etc.; the vacuum degree can be 1Pa, 2Pa, 3Pa, 4Pa, 5Pa, etc. During the de-doping treatment, the flow rate of carbon dioxide can be 500Nm 3 / h、600Nm 3 / h、700Nm 3 / h、800Nm 3 / h、900Nm 3 / h、1000Nm 3 / h、1100Nm 3 / h、1200Nm 3 / h、1300Nm 3 / h、1400Nm 3 / h、1500Nm 3 / h, etc.; the addition time of carbon dioxide can be 3T min, 4T min, 5T min, 6T min, etc.

[0060] S6. Under the second preset process parameters, argon gas is added to the fourth alloy liquid to react with the silicon-based material to carry out a carbon-silicon-oxygen reaction to obtain a first iron-based nickel-chromium alloy liquid.

[0061] In some embodiments, the second predetermined carbon content is ≤ 0.01%.

[0062] In some embodiments, the second preset process parameters include: a temperature of 1550° C. to 1570° C., a vacuum degree of 5 Pa to 10 Pa; and / or,

[0063] In the carbon-silicon-oxygen reaction, the flow rate of argon is 2000 Nm 3 / h~4000Nm 3 / h, the argon addition time is (4-9) × T (min, T represents the nominal capacity of the vacuum smelting furnace, in tons.

[0064] In the embodiment of the present application, the carbon content in the fourth alloy liquid is ≤0.01%, and the carbon-oxygen reaction rate is further reduced. It can be seen from the C, Si, O reaction equilibrium equations (2) and (3) under vacuum that when C is lower than 0.01% and Si is higher than 0.1% under vacuum, gaseous SiO can be generated. The deoxidation reaction produced at this stage is gaseous SiO, which does not affect the alloy liquid inclusions. When the carbon content is higher than 0.01%, the oxidation product of Si may be SiO2 solid inclusions, and the solid deoxidation product will be retained in the alloy liquid, thereby causing the inclusion content of the alloy liquid to increase. The second preset process parameters include: the temperature can be 1550℃~1570℃, the vacuum degree can be 5Pa~10Pa, further reducing the temperature and increasing the pressure, thereby further inhibiting the decomposition of the crucible. The flow rate of argon gas can be 2000Nm 3 / h~4000Nm 3 / h, the addition time of argon can be (4~9)×T min, making full use of the vacuum chamber effect of argon bubbles, CO in Ar bubbles is decomposed to 0, therefore, for the decarburization reaction to generate CO products, Ar bubbles are equivalent to a vacuum chamber, which reduces the CO partial pressure and promotes decarburization and deoxidation. Exemplarily, in the second preset process parameters, the temperature is 1550℃, 1555℃, 1560℃, 1565℃, 1570℃, etc.; the vacuum degree can be 5Pa, 6Pa, 7Pa, 8Pa, 9Pa, etc. In the carbon-silicon-oxygen reaction, the flow rate of the argon can be 2000Nm 3 / h、2500Nm 3 / h、3000Nm 3 / h、3500Nm 3 / h、4000Nm 3 / h, etc.; the adding time of argon can be 4T min, 5T min, 6T min, 7T min, 8T min, 9T min, etc. The adding amount of the silicon-based material is 0.01% to 0.015%, the silicon content of the silicon-based material is more than 99.9wt%, and the silicon-based material can be one or more of ferrosilicon and pure silicon.

[0065] [Si]+2[O]+[C]→CO↑+SiO↑

[0066] △G 0 =13577-17.065T Formula (2)

[0067]

[0068] In some embodiments, under the second preset process parameters, argon is added to the fourth alloy liquid to react with the silicon-based material to carry out a carbon-silicon-oxygen reaction to obtain a first iron-based nickel-chromium alloy liquid. After obtaining the first iron-based nickel-chromium alloy liquid, the method further includes:

[0069] S7. In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of argon gas (Ar) is 1000Pa-4000Pa, the standing time is (2-5)×(H / 1.2)min, and H represents the height of the container containing the first iron-based nickel-chromium alloy liquid.

[0070] In the embodiment of the present application, in a vacuum environment containing argon, it is indicated that Ar is added to the vacuum chamber, and the pressure of argon can be 1000Pa~4000Pa, which can reduce the risk of decomposition of the MgO crucible and reduce the volatilization loss of alloy elements in the first iron-based nickel-chromium alloy liquid. The standing time can be (2~5)×(H / 1.2)min, and the refractory materials and other inclusions brought into the first iron-based nickel-chromium alloy liquid are fully floated and removed. Exemplarily, the pressure of the argon gas can be 1000Pa, 2000Pa, 3000Pa, 4000Pa, etc.; the standing time can be 2×(H / 1.2)min, 3×(H / 1.2)min, 4×(H / 1.2)min, 5×(H / 1.2)min, and the container for holding the first iron-based nickel-chromium alloy liquid can be a MgO crucible.

[0071] In some embodiments, the chemical composition of the target iron-based nickel-chromium alloy liquid includes, by mass fraction: C<0.006%, Al<0.001%, 10%≤Cr≤30%, 10%≤Ni≤20%, Si<0.15%, Mn<0.05%, [O] (total oxygen)<10ppm, N<5ppm, and Fe;

[0072] The D-type inclusions in the target iron-based nickel-chromium alloy liquid are below level 0.5.

[0073] It should be noted that Fe is a matrix element, and the specific content / content range of Fe can be obtained by the upper and lower limit formula of the component, that is: the sum of the percentage content of each component in a composition should be equal to 100%, and the content range of several components should meet the following conditions: the upper limit value of a component + the lower limit value of other components ≤ 100; the lower limit value of a component + the upper limit value of other components ≥ 100.

[0074] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0075] Example 1

[0076] A method for smelting an iron-based nickel-chromium alloy, using a vacuum induction furnace for smelting, the vacuum induction furnace has a nominal capacity of 1 ton, the method comprising:

[0077] Melting high-purity iron, high-purity nickel and high-purity iron and vacuum deoxidizing them to obtain a first alloy liquid containing iron, nickel and chromium; wherein the melting temperature is 1550° C., vacuum deoxidation is performed to a vacuum degree of 9 Pa, and the total loading amount T is 1.0 ton;

[0078] According to the oxygen content of the first alloy liquid, the theoretical weight of carbon is obtained; wherein, when the oxygen content is 70 ppm, the theoretical weight of carbon is 0.234%;

[0079] A theoretical amount of carbon is added to the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid; wherein the process parameters of the carbon-oxygen reaction include: a temperature of 1600° C., a vacuum degree of 0.1 Pa, and a time of 10 minutes.

[0080] Add carbon dioxide to the second alloy liquid for decarburization reaction to obtain a third alloy liquid containing the first preset carbon content; wherein the flow rate of carbon dioxide is 1000Nm 3 / h, the addition time is 5min, and the first preset carbon content is 0.014%;

[0081] Under the first preset process parameters, carbon dioxide is added to the third alloy liquid so that the bubbles of carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content; wherein the first preset process parameters include: a temperature of 1570°C, a vacuum degree of 5Pa; a flow rate of carbon dioxide of 500Nm 3 / h, the addition time is 3min, and the second preset carbon content is 0.009%;

[0082] Under the second preset process parameters, argon is added to the fourth alloy liquid to react with ferrosilicon with carbon, silicon and oxygen to obtain a first iron-based nickel-chromium alloy liquid; wherein the second preset process parameters include: temperature of 1550°C, vacuum of 5Pa; argon flow rate of 2000Nm 3 / h, the adding time is 4min; the silicon content of ferrosilicon is 99.97%, the adding amount of ferrosilicon is 0.01%; the carbon content of the first iron-based nickel-chromium alloy liquid is 0.005%;

[0083] In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of the argon gas is 1000 Pa and the standing time is 2 minutes.

[0084] Example 2

[0085] A method for smelting an iron-based nickel-chromium alloy, using a vacuum induction furnace for smelting, the vacuum induction furnace has a nominal capacity of 3 tons, the method comprising:

[0086] Melting high-purity iron, high-purity nickel and high-purity iron and vacuum deoxidizing them to obtain a first alloy liquid containing iron, nickel and chromium; wherein the melting temperature is 1580°C, vacuum deoxidation is performed to a vacuum degree of 6Pa, and the total loading amount is 2 tons;

[0087] According to the oxygen content of the first alloy liquid, the theoretical weight of carbon is obtained; wherein, when the oxygen content is 160 ppm, the theoretical weight of carbon is 0.342%;

[0088] A theoretical amount of carbon is added to the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid; wherein the process parameters of the carbon-oxygen reaction include: a temperature of 1640° C., a vacuum degree of 5 Pa, and a time of 30 minutes.

[0089] Add carbon dioxide to the second alloy liquid for decarburization reaction to obtain a third alloy liquid containing the first preset carbon content; wherein the flow rate of carbon dioxide is 3000Nm 3 / h, the addition time is 20min, and the first preset carbon content is 0.013%;

[0090] Under the first preset process parameters, carbon dioxide is added to the third alloy liquid so that the bubbles of carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content; wherein the first preset process parameters include: a temperature of 1600°C, a vacuum degree of 5Pa; a flow rate of carbon dioxide of 1500Nm 3 / h, the addition time is 12min, and the second preset carbon content is 0.009%;

[0091] Under the second preset process parameters, argon is added to the fourth alloy liquid to react with ferrosilicon with carbon, silicon and oxygen to obtain a first iron-based nickel-chromium alloy liquid; wherein the second preset process parameters include: temperature of 1570°C, vacuum degree of 10Pa; argon flow rate of 4000Nm 3 / h, the adding time is 18min; the silicon content of ferrosilicon is 99.97%, the adding amount of ferrosilicon is 0.015%; the carbon content of the first iron-based nickel-chromium alloy liquid is 0.006%;

[0092] In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of the argon gas is 4000 Pa and the standing time is 10 minutes.

[0093] Example 3

[0094] A method for smelting an iron-based nickel-chromium alloy, using a vacuum induction furnace for smelting, the vacuum induction furnace has a nominal capacity of 2 tons, the method comprising:

[0095] Melting high-purity iron, high-purity nickel and high-purity iron and vacuum deoxidizing them to obtain a first alloy liquid containing iron, nickel and chromium; wherein the melting temperature is 1550° C., vacuum deoxidation is performed to a vacuum degree of 9 Pa, and the total loading amount is 2 tons;

[0096] According to the oxygen content of the first alloy liquid, the theoretical weight of carbon is obtained; wherein, the oxygen content is 42 ppm and the theoretical weight of carbon is 0.2%;

[0097] A theoretical amount of carbon is added to the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid; wherein the process parameters of the carbon-oxygen reaction include: a temperature of 1620° C., a vacuum degree of 2 Pa, and a time of 20 minutes.

[0098] Add carbon dioxide to the second alloy liquid for decarburization reaction to obtain a third alloy liquid containing the first preset carbon content; wherein the flow rate of carbon dioxide is 2000Nm 3 / h, the addition time is 14min, and the first preset carbon content is 0.015%;

[0099] Under the first preset process parameters, carbon dioxide is added to the third alloy liquid so that the bubbles of carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content; wherein the first preset process parameters include: a temperature of 1585°C, a vacuum degree of 3Pa; a flow rate of carbon dioxide of 1000Nm 3 / h, the addition time is 8min; the second preset carbon content is 0.01%;

[0100] Under the second preset process parameters, argon is added to the fourth alloy liquid to react with ferrosilicon with carbon, silicon and oxygen to obtain a first iron-based nickel-chromium alloy liquid; wherein the second preset process parameters include: temperature of 1560°C, vacuum degree of 7Pa; argon flow rate of 3000Nm 3 / h, the adding time is 12min; the silicon content of ferrosilicon is 99.97%, the adding amount of ferrosilicon is 0.013%; the carbon content of the first iron-based nickel-chromium alloy liquid is 0.004%;

[0101] In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of the argon gas is 3000 Pa and the standing time is 4 minutes.

[0102] Comparative Example 1

[0103] A method for smelting an iron-based nickel-chromium alloy, using a vacuum induction furnace for smelting, the vacuum induction furnace has a nominal capacity of 2 tons, the method comprising:

[0104] Melting high-purity iron, high-purity nickel and high-purity iron and vacuum deoxidizing them to obtain a first alloy liquid; wherein the melting temperature is 1550° C., vacuum deoxidation is performed to a vacuum degree of 9 Pa, and the total loading amount is 2 tons;

[0105] According to the oxygen content of the first alloy liquid, the theoretical weight of carbon is obtained; wherein the total oxygen content is 42 ppm and the added weight of carbon is 0.1%;

[0106] The first alloy liquid is first smelted with carbon having a theoretical weight to obtain a second alloy liquid; wherein the process parameters of the carbon-oxygen reaction include: a temperature of 1620° C., a vacuum degree of 2 Pa, and a time of 20 minutes; and the carbon content of the second alloy liquid is 0.07%;

[0107] The second alloy liquid is subjected to a second smelting to obtain a third alloy liquid; wherein the process parameters of the second smelting are: temperature of 1580° C., vacuum degree of 3 Pa; the carbon content of the third alloy liquid is 0.065%;

[0108] The third alloy liquid is subjected to a third smelting to obtain a target iron-based nickel-chromium alloy liquid; wherein the process parameters of the second smelting are: temperature of 1560° C., and vacuum degree of 7 Pa.

[0109] Comparative Example 2

[0110] Based on the disclosure of Example 3, the difference between Comparative Example 2 and Example 3 is that: no silicon-based material is added; and the carbon content of the first iron-based nickel-chromium alloy liquid is 0.007%.

[0111] The target iron-based nickel-chromium alloy liquids obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for chemical composition, and the test results are shown in Table 1.

[0112] Table 1 Chemical composition of target iron-based nickel-chromium alloy liquid, the rest is Fe

[0113]

[0114] As shown in Table 1, the chemical composition of the iron-based nickel-chromium alloy liquid finally obtained in the embodiment of the present application satisfies: C<0.006%, Al<0.001%, 10%≤Cr≤30%, 10%≤Ni≤20%, Si<0.15%, Mn<0.05%, [O] (total oxygen)<10ppm, N<5ppm, and Fe; the D-type inclusions in the iron-based nickel-chromium alloy liquid are below level 0.5. However, the carbon content of Comparative Example 1 is low, bottom blowing of CO2 and Ar is not adopted, staged control is not adopted, ferrosilicon is not added, the alloy purification smelting effect is poor, the total oxygen content of the alloy liquid is 30ppm, and the D-type inclusions are level 2.5; Comparative Example 2 does not add ferrosilicon, the carbon content of the alloy liquid is 0.007%, the total oxygen content of the alloy liquid is 15.0ppm, and the D-type inclusions are level 1.5, which does not meet the technical requirements of ultra-pure, iron-based nickel-chromium alloy.

[0115] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0116] (1) The method for smelting an iron-based nickel-chromium alloy provided in the embodiment of the present application is a vacuum induction smelting under low-carbon and low-aluminum conditions, which does not adopt a precipitation deoxidation method, and provides a feasible method for synergistically controlling deoxidation and crucible decomposition of oxygen through different carbon-oxygen reaction stages;

[0117] (2) The smelting method for smelting iron-based nickel-chromium alloy provided in the embodiment of the present application utilizes CO2 to generate CO during the smelting process, which not only achieves the effects of weak oxidation and bubble metallurgy, but also provides a new idea for the application of CO2 in metallurgical processes;

[0118] (3) The smelting method for iron-based nickel-chromium alloy provided in the embodiment of the present application abandons the idea of ​​simply increasing the temperature and vacuum degree, and provides a new idea for low-energy consumption and ultra-pure smelting.

[0119] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. A method for smelting an iron-based nickel-chromium alloy, the method being vacuum smelting, the method comprising: Obtaining a first alloy liquid containing iron, nickel and chromium; Obtaining a theoretical weight of carbon according to the oxygen content of the first alloy liquid; Adding the carbon having a theoretical weight into the first alloy liquid to carry out a carbon-oxygen reaction to obtain a second alloy liquid; adding carbon dioxide to the second alloy liquid to perform a decarburization reaction to obtain a third alloy liquid containing a first preset carbon content; Under the first preset process parameters, adding carbon dioxide to the third alloy liquid so that bubbles of the carbon dioxide produce a vacuum chamber effect to remove impurities from the third alloy liquid to obtain a fourth alloy liquid containing a second preset carbon content; Under the second preset process parameters, argon gas is added to the fourth alloy liquid to carry out a carbon-silicon-oxygen reaction with the silicon-based material to obtain a first iron-based nickel-chromium alloy liquid.

2. The method according to claim 1, characterized in that The theoretical weight of the carbon satisfies the following relationship: 0.15％+1.2×a Wherein, a represents the oxygen content of the first alloy liquid, in ppm.

3. The method according to claim 1, characterized in that The process parameters of the carbon-oxygen reaction include: a temperature of 1600° C. to 1640° C. and a vacuum degree of 0.1 Pa to 5 Pa.

4. The method according to claim 1, characterized in that: In the decarbonization reaction, the flow rate of carbon dioxide is 1000Nm 3 / h~3000Nm 3 / h, the adding time of carbon dioxide is (5~10)×T min, where T represents the nominal capacity of the vacuum smelting furnace, in tons.

5. The method according to claim 1, characterized in that The first preset carbon content is ≤0.015%.

6. The method according to claim 1 or 5, characterized in that: The first preset process parameters include: temperature of 1570° C. to 1600° C., vacuum degree of 1 Pa to 5 Pa; and / or, During the impurity removal process, the flow rate of carbon dioxide is 500 Nm 3 / h~1500Nm 3 / h, the adding time of carbon dioxide is (3~6)×T min, where T represents the nominal capacity of the vacuum smelting furnace, in tons.

7. The method according to claim 1, characterized in that The second preset carbon content is ≤0.01%.

8. The method according to claim 1 or 7, characterized in that: The second preset process parameters include: temperature of 1550°C to 1570°C, vacuum degree of 5Pa to 10Pa; and / or, In the carbon-silicon-oxygen reaction, the flow rate of argon is 2000 Nm 3 / h~4000Nm 3 / h, the argon addition time is (4~9)×T min, where T represents the nominal capacity of the vacuum smelting furnace, in tons.

9. The method according to claim 1, characterized in that: After adding argon gas to the fourth alloy liquid under the second preset process parameters to react with the silicon-based material to obtain a first iron-based nickel-chromium alloy liquid, the method further includes: In a vacuum environment containing argon gas, the first iron-based nickel-chromium alloy liquid is allowed to stand to obtain a target iron-based nickel-chromium alloy liquid; wherein the pressure of the argon gas is 1000Pa~4000Pa, the standing time is (2~5)×(H / 1.2)min, and H represents the height of the container containing the first iron-based nickel-chromium alloy liquid.

10. The method according to claim 9, characterized in that The chemical composition of the target iron-based nickel-chromium alloy liquid includes, by mass fraction, C<0.006%, Al<0.001%, 10%≤Cr≤30%, 10%≤Ni≤20%, Si<0.15%, Mn<0.05%, [O]<10ppm, N<5ppm, and Fe; The D-type inclusions in the target iron-based nickel-chromium alloy liquid are below level 0.5.

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