Nickel-magnesium intermediate alloy for high-temperature alloy and preparation method of nickel-magnesium intermediate alloy

Abstract

The invention discloses a nickel-magnesium intermediate alloy for a high-temperature alloy and a preparation method thereof.The nickel-magnesium intermediate alloy is composed of, by mass, 4%-50% of Mg and the balance Ni and inevitable impurities, and the method comprises the steps that firstly, electrolytic nickel and magnesium ingot raw materials are selected, cut and polished, and ingredients are calculated, weighed and subpackaged; 2, the raw materials are put into a crucible of an induction melting furnace to be smelted, and alloy melt is obtained; and thirdly, a steam suction filtration system is started, the alloy melt is poured into a cast iron ingot mold, and the nickel-magnesium intermediate alloy ingot is obtained after cooling. A proper amount of inert gas is introduced in the vacuum induction smelting process, smelting and pouring in a micro-negative pressure state are guaranteed, impurity introduction in the smelting and pouring processes is reduced by controlling smelting process parameters, meanwhile, gasification loss of the magnesium element is reduced, and the high-strength magnesium alloy with uniform components and high strength is obtained. The nickel-magnesium intermediate alloy is high in cleanliness and low in content of harmful gas elements and inclusions, and is suitable for the field of downstream high-temperature alloys.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy preparation, and in particular relates to a nickel-magnesium master alloy for high-temperature alloys and a preparation method thereof. Background Art

[0002] High-temperature alloys are widely used in environments where materials need to withstand high temperatures. They are key hot-end component materials for modern aircraft engines, aerospace equipment, ships, and industrial gas turbines. In the preparation process of high-temperature alloys, magnesium is generally added in the form of nickel-magnesium master alloys in the last step after refining and before the finished product. Therefore, the quality of the nickel-magnesium master alloy directly affects the performance and quality of the high-temperature alloy material. For nickel-magnesium master alloys, since the melting point of nickel (1452°C) is much higher than the melting point of magnesium (620°C), and metallic magnesium has the characteristics of high vapor pressure and non-induction, the production process of nickel-magnesium master alloys is accompanied by a lot of smoke and even explosions, the magnesium recovery rate is low, and the uniformity of magnesium in the alloy and the accuracy of magnesium content are difficult to control.

[0003] The invention patent with the patent publication number CN116694957A discloses a nickel-magnesium alloy with a Mg content of 9% to 17% and a preparation method thereof. The method uses high-specification electrolytic nickel and native magnesium ingots as raw materials, and is smelted in an induction smelting furnace under the protection of pressurized inert gas. In the later stage of smelting, argon is blown into the bottom of the equipment to stir the melt, promote alloy homogenization, and form bubbles in the melt to drive inclusions to float and improve the purity of the alloy. The pouring process uses a chute made of high-magnesium refractory materials and is equipped with magnesium-based foam ceramics to filter and purify the alloy, and finally solidifies rapidly in a water-cooled crystallizer. This preparation method can prepare a nickel-magnesium alloy with uniform composition and high purity, but the equipment required for this method is complex. Argon needs to be blown from the bottom of the smelting process, and inclusions in the alloy need to be removed through the chute and foam ceramics during the pouring process. The process flow is relatively complicated, and the equipment preparation work before smelting is relatively cumbersome.

[0004] The invention patent with the patent publication number CN112593102A discloses a method for preparing a nickel-magnesium hydrogen storage alloy with a Mg content of 75% to 78%. The method puts the dried magnesium ingot and the nickel plate into a non-vacuum medium-frequency electromagnetic induction furnace for heating, and first heats 60% to 85% of the magnesium ingot, and introduces SF 6 and N 2 , until the magnesium ingot is completely melted, then the nickel plate is added, and after the nickel plate is completely melted and the melt is stirred, the remaining magnesium ingot is added again to cool the melt, and finally the nickel-magnesium intermediate alloy is cast. This method has low equipment requirements and a simple production process, but it uses a non-vacuum melting process and SF is introduced for a long time during the melting process. 6 and N 2 , where SF 6The gas is a strong greenhouse gas with a carbon emission equivalent coefficient of 23,900 and a half-life of 3,200 years. It is one of the six greenhouse gases restricted by international conventions. This method is obviously not in line with the concept of sustainable development, and a more environmentally friendly method should be adopted to produce nickel-magnesium intermediate alloys.

[0005] The invention patent with the patent publication number CN100473734A discloses a method for smelting a nickel-magnesium alloy with a Mg content of 8% to 49%. The method designs four raw material charging methods, uses a vacuum coreless induction furnace for smelting, and the furnace lining is made of magnesia sand. After adding metal raw materials into the furnace, pre-molten slag mainly containing NaCl and KCl is added. During the smelting process, the furnace is manually shaken at least twice and argon gas is passed through for protection after the charge is melted. Finally, it is poured into a refractory ingot mold to finally prepare a nickel-magnesium alloy. However, the method does not clearly explain the treatment method of the pre-molten slag during the production process, and the materials of the smelting furnace lining and the casting ingot mold are both refractory, which makes it difficult to avoid inclusions introduced by the refractory in the alloy. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a nickel-magnesium master alloy for high-temperature alloys in view of the deficiencies of the above-mentioned prior art. The method introduces an appropriate amount of inert gas during vacuum induction melting to ensure melting and pouring under a slightly negative pressure, and combines the control of melting process parameters to reduce the introduction of impurities during melting and casting, while reducing the gasification loss of magnesium elements, thereby obtaining a nickel-magnesium master alloy with uniform composition, high cleanliness, and low content of harmful gas elements and inclusions, thereby solving the problems of the existing nickel-magnesium master alloy preparation process being complex, having high equipment requirements, being easy to introduce impurities, and having poor environmental protection.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a nickel-magnesium master alloy for high-temperature alloys, the nickel-magnesium master alloy is composed of the following elements in mass percentage: Mg 4% to 50%, the balance being Ni and unavoidable impurities, characterized in that the method comprises the following steps: Step 1: Select electrolytic nickel and magnesium ingots as raw materials, cut and grind the raw materials, calculate the ingredients according to the ratio of nickel-magnesium master alloy for high-temperature alloy of the target product, and weigh and package them; Step 2: Put the weighed raw materials in step 1 into the crucible of the induction melting furnace, evacuate the furnace and heat it for melting. After the raw materials turn red, fill them with argon gas. After all the raw materials are melted, reduce the power by 10kW~30kW and continue melting for 5min~10min to obtain an alloy melt in the crucible. Step 3: Start the steam filtration system of the induction melting furnace, pour the alloy melt in the crucible in step 2 into the cast iron ingot mold, cool for 10h~12h, open the furnace and take samples to obtain the nickel-magnesium intermediate alloy ingot, and then refine, screen, inspect and package the nickel-magnesium intermediate alloy ingot.

[0008] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the unavoidable impurities include the following elements in mass percentage: Ag≤0.001%, Co≤0.01%, Fe≤0.1%, Mn≤0.05%, Cu≤0.003%, As≤0.002%, Sn≤0.001%, Zn≤0.002%, Si≤0.02%, P≤0.01%, C≤0.05%, S≤0.005%, O≤0.005%, and N≤0.007%.

[0009] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the electrolytic nickel in step one meets the Ni9999 specification and composition requirements in GB / T 6516-2010 "Electrolytic Nickel", and the magnesium ingot meets the composition requirements of Mg9995 in GB / T 3499-2003 "Native Magnesium Ingot".

[0010] The present invention strictly controls the content of impurity elements in the nickel-magnesium master alloy raw material, thereby further ensuring that the nickel-magnesium master alloy with uniform composition and high cleanliness is prepared through vacuum induction melting.

[0011] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the length, width and thickness of the magnesium ingot after cutting and polishing in step 1 are 10cm~15cm, 5cm~10cm and 3cm~5cm respectively, and the length, width and thickness of the electrolytic nickel after cutting and polishing are 3cm~5cm, 3cm~5cm and 0.5cm~1.5cm respectively. The present invention polishes the surface of the raw material to remove oil and other impurities that may exist on the surface of the raw material, ensures the cleanliness of the raw material, controls the size of the raw material by cutting, promotes vacuum induction melting, and shortens the cycle of preparing the nickel-magnesium master alloy.

[0012] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the crucible in step 2 is a molybdenum crucible with a mass purity of 99.95%. The present invention uses a molybdenum crucible with a high melting point, which can induce heat to promote the melting and mixing of raw materials on the one hand, and avoid impurities introduced by the contact between the alloy melt and the smelting container during the smelting process, which is beneficial to improve the purity of the nickel-magnesium master alloy.

[0013] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the vacuum in step 2 is evacuated to a vacuum degree not exceeding 5×10 -1 Pa. The present invention evacuates the vacuum to a degree not exceeding 5×10 -1 Pa, reducing the harmful gas elements that may be introduced into the residual air in the furnace, is beneficial to improving the purity of the nickel-magnesium master alloy.

[0014] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that the power transmission heating smelting mode in step 2 is a step-by-step power transmission heating, which gradually adjusts and increases the smelting power and maintains each power for 10 minutes to 15 minutes. The step-by-step power transmission heating of the present invention makes the raw material melting process relatively smooth, avoids excessive power causing a rapid temperature rise, and thus avoids the gasification loss of magnesium element.

[0015] The above-mentioned method for preparing a nickel-magnesium master alloy for high-temperature alloys is characterized in that, in step 2, after the raw material turns red, argon is filled to -0.045MPa±0.005MPa. In the smelting process of the present invention, an appropriate amount of inert gas is controlled to be introduced into the furnace before the magnesium ingot is melted, which effectively ensures that the induction smelting process is carried out under a slightly negative pressure state, and effectively reduces the gasification loss of the Mg element during the smelting process, thereby preparing a nickel-magnesium master alloy with uniform composition, high cleanliness, and low content of harmful gas elements and inclusions, providing high-quality raw materials for downstream high-temperature alloy smelting.

[0016] The above-mentioned method for preparing a nickel-magnesium intermediate alloy for a high-temperature alloy is characterized in that the steam extraction system in step three includes a condenser arranged at the furnace body interface of the induction melting furnace, the interior of the condenser is provided with a superimposed water-cooled baffle, and an oil pool filter is provided at the rear end of the condenser. In view of the problem that magnesium vapor volatilizes during the smelting process due to the low melting point of magnesium and reduces the visibility in the furnace, the present invention specially configures a steam extraction system for the induction melting furnace, and arranges a superimposed water-cooled baffle inside the condensing tank to condense and collect the magnesium vapor volatilized during the smelting process, and arranges an oil pool filter at the rear end of the condensing tank to collect the residual magnesium vapor; usually, the steam extraction system is started before the alloy melt obtained by smelting is poured, and a large amount of magnesium vapor is extracted from the furnace in a short time to realize the visualization of the pouring process, so that the alloy melt can be poured into the cast iron ingot mold more efficiently while ensuring the safe operation of the pouring process, avoiding the use of cumbersome pouring and drainage devices and the possible introduction of impurities, thereby improving production efficiency and reducing the introduction of impurities; at the same time, since the duration from the start of the extraction system to the completion of pouring is short, the extraction system is not continuously turned on during the entire smelting process, which will not cause a large amount of gasification loss of magnesium raw materials, and thus has little effect on the composition content of the alloy melt, and has no effect on the uniformity and accuracy of the nickel-magnesium intermediate alloy ingot obtained after the final solidification.

[0017] The present invention controls the cooling time to ensure that the furnace is opened for sampling after the nickel-magnesium master alloy ingot components are cooled, and at the same time allows a small amount of magnesium vapor remaining in the furnace to fully adhere or precipitate, thereby avoiding potential safety hazards caused by premature furnace opening.

[0018] At the same time, the present invention also discloses a nickel-magnesium intermediate alloy for high-temperature alloys, which is characterized in that it is prepared by the above method.

[0019] Compared with the prior art, the present invention has the following advantages: 1. Different from the common induction melting process, the method for preparing the nickel-magnesium master alloy of the present invention introduces an appropriate amount of inert gas during the vacuum induction melting process to ensure melting and pouring under a slightly negative pressure state, so as to reduce the vapor pressure of magnesium and inhibit magnesium evaporation, thereby preparing the low-melting-point metal magnesium and the high-melting-point metal nickel into a nickel-magnesium master alloy with a moderate melting point, avoiding the smoke, fire and even explosion problems easily caused in the melting process due to the low melting point and high vapor pressure of magnesium, and at the same time helping to improve the yield of magnesium in the melting process.

[0020] 2. The present invention adopts a high-purity molybdenum crucible as a smelting container to effectively promote the melting and mixing of raw materials, avoid impurities introduced by the contact between the alloy melt and the crucible during the smelting process, and at the same time, before pouring the alloy melt, a steam extraction system is used to extract the magnesium vapor in the furnace to realize the visualization of the pouring process, avoiding the introduction of impurities caused by the contact between the cumbersome pouring and drainage device and the alloy melt. In addition, the preparation method of the present invention does not involve slag protection measures, thereby ensuring the cleanliness of the nickel-magnesium intermediate alloy.

[0021] 3. The present invention evacuates the vacuum to a degree not exceeding 5×10 -1 Pa is followed by electric heating for smelting, which effectively reduces harmful gas elements that may be introduced into the furnace by residual air. By adopting stepped electric heating, the rapid temperature rise caused by excessive power and the subsequent gasification loss of magnesium element can be avoided. By introducing a proper amount of inert gas into the furnace before the magnesium ingot is melted, the gasification loss of Mg element during the smelting process can be reduced while ensuring that the vacuum is not broken, thereby ensuring the accuracy and stability of the composition of the nickel-magnesium intermediate alloy.

[0022] 4. The present invention adopts a vacuum induction melting method to prepare a nickel-magnesium master alloy. The equipment is simple and easy to operate, and the configured steam extraction device can effectively extract the magnesium vapor in the furnace, ensuring the safety of the production process. In addition, the production process does not involve factors such as polluting gases, which is more environmentally friendly.

[0023] 5. The method for preparing the nickel-magnesium master alloy of the present invention is simple and applicable, and is suitable for large-scale and large-volume industrial production.

[0024] 6. The nickel-magnesium intermediate alloy prepared by the present invention has uniform composition, high cleanliness and no inclusions, and low content of harmful gas elements in the alloy. It can be used as a smelting additive for high-temperature alloys and can be crushed into alloy blocks with a size of less than 50 mm. It also reduces the burning loss of low-melting-point element magnesium, reduces the introduction of harmful gas elements and inclusions, shortens the alloy melting time, and is conducive to the rapid diffusion of alloy elements in the high-temperature alloy melt, thereby obtaining a high-temperature alloy product with more uniform composition and superior performance.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The schematic diagram of the structure of the steam extraction and filtration system configured for the induction melting furnace in the present invention.

[0027] Figure 2 This is a SEM scan of the nickel-magnesium master alloy prepared in Example 1 of the present invention.

[0028] Figure 3 This is the distribution diagram of Ni element in the nickel-magnesium master alloy prepared in Example 1 of the present invention.

[0029] Figure 4 This is the distribution diagram of Mg element in the nickel-magnesium master alloy prepared in Example 1 of the present invention.

[0030] Description of Reference Numerals DETAILED DESCRIPTION

[0031] like Figure 1 As shown, the steam extraction system configured for the induction melting furnace in the present invention includes a condensing tank 2 arranged at the interface of the furnace body 1 of the induction melting furnace, a stacked water-cooling baffle 3 is arranged inside the condensing tank 2, and an oil pool filter 4 is arranged at the rear end of the condensing tank 2.

[0032] Example 1 The nickel-magnesium master alloy for high-temperature alloy of this embodiment is composed of the following elements in percentage by mass: Mg 15%, and the balance Ni and unavoidable impurities.

[0033] The method for preparing the nickel-magnesium master alloy for high-temperature alloy of the present embodiment comprises the following steps: Step 1: Select electrolytic nickel and magnesium ingots as raw materials, cut and grind the raw materials to remove surface oil and scale, calculate the ingredients according to the ratio of the target product nickel-magnesium master alloy for high-temperature alloy, and weigh and pack 42 kg of plate-shaped electrolytic nickel and 8 kg of magnesium ingots; The electrolytic nickel meets the Ni9999 specification and composition requirements in GB / T 6516-2010 "Electrolytic Nickel", and the magnesium ingot meets the composition requirements of Mg9995 in GB / T 3499-2003 "Native Magnesium Ingot", and the magnesium ingot after cutting and grinding is a small block with a length, width and thickness of 10cm-15cm, 5cm-10cm and 3cm-5cm respectively, and the electrolytic nickel after cutting and grinding is a plate with a length, width and thickness of 3cm-5cm, 3cm-5cm and 0.5cm-1.5cm respectively; Step 2: Place the plate-shaped electrolytic nickel and magnesium ingot pieces weighed and packed in step 1 into a molybdenum crucible with a mass purity of 99.95% in an induction melting furnace, with the magnesium ingot pieces at the bottom and the plate-shaped electrolytic nickel at the top. Close the lid of the induction melting furnace and evacuate to a vacuum degree of 2.3×10 -1 Pa, and then start the heating power supply to heat and melt, adopt step-by-step power supply heating, and keep it at 20kW, 55kW, and 85kW power for 15 minutes respectively. When the power is maintained at 55kW, the raw material turns red and argon is filled to -0.045MPa. Then the power is increased to 100kW until the raw material is completely melted, and then the power is reduced to 80kW to continue melting for 10 minutes to obtain alloy melt in the crucible; Step 3: Start the steam filtration system of the induction melting furnace, pour the alloy melt in the crucible in step 2 into the cast iron ingot mold, open the furnace and take samples after cooling for 10 hours to obtain the nickel-magnesium intermediate alloy ingot, and then refine, screen, inspect and package the nickel-magnesium intermediate alloy ingot.

[0034] The composition of the nickel-magnesium master alloy ingot prepared in this example was tested, and the results are shown in Table 1 below.

[0035] Table 1 Chemical composition of the nickel-magnesium master alloy ingot prepared in Example 1 (wt.%)

[0036] As can be seen from Table 1, the nickel-magnesium master alloy prepared in this embodiment contains very low levels of impurity elements, especially oxygen and nitrogen, which avoids affecting the cleanliness of downstream high-temperature alloys.

[0037] Figure 2 This is a SEM scan of the nickel-magnesium master alloy prepared in this embodiment. Figure 3 and Figure 4 The distribution diagrams of Ni and Mg in the nickel-magnesium master alloy prepared in this embodiment are shown in FIG. Figure 2~Figure 4 It can be seen that the nickel and magnesium elements in the nickel-magnesium master alloy are uniformly distributed as a whole, no inclusions are found in the nickel-magnesium master alloy, and there is no segregation phenomenon.

[0038] Example 2 The nickel-magnesium master alloy for high-temperature alloy of the present embodiment is composed of the following elements in percentage by mass: Mg 4%, and the balance Ni and unavoidable impurities.

[0039] The method for preparing the nickel-magnesium master alloy for high-temperature alloy of the present embodiment comprises the following steps: Step 1: Select electrolytic nickel and magnesium ingots as raw materials, cut and grind the raw materials to remove surface oil and scale, calculate the ingredients according to the ratio of the target product nickel-magnesium master alloy for high-temperature alloy, and weigh and pack 48 kg of plate-shaped electrolytic nickel and 2.3 kg of magnesium ingots; The electrolytic nickel meets the Ni9999 specification and composition requirements in GB / T 6516-2010 "Electrolytic Nickel", and the magnesium ingot meets the composition requirements of Mg9995 in GB / T 3499-2003 "Native Magnesium Ingot", and the magnesium ingot after cutting and grinding is a small block with a length, width and thickness of 10cm-15cm, 5cm-10cm and 3cm-5cm respectively, and the electrolytic nickel after cutting and grinding is a plate with a length, width and thickness of 3cm-5cm, 3cm-5cm and 0.5cm-1.5cm respectively; Step 2: Place the plate-shaped electrolytic nickel and magnesium ingot pieces weighed and packed in step 1 into a molybdenum crucible with a mass purity of 99.95% in an induction melting furnace, with the magnesium ingot pieces at the bottom and the plate-shaped electrolytic nickel at the top. Close the lid of the induction melting furnace and evacuate to a vacuum degree of 4.6×10 -1 Pa, and then start the heating power supply to heat and melt, using step-by-step power supply heating, and keep it at 20kW, 55kW, and 85kW for 15 minutes respectively. When the power is maintained at 55kW, the raw material turns red and argon is filled to -0.04MPa. Then the power is increased to 100kW until the raw material is completely melted, and then the power is reduced to 90kW to continue melting for 5 minutes to obtain an alloy melt in the crucible; Step 3: Start the steam filtration system of the induction melting furnace, pour the alloy melt in the crucible in step 2 into the cast iron ingot mold, open the furnace and take samples after cooling for 10 hours to obtain the nickel-magnesium intermediate alloy ingot, and then refine, screen, inspect and package the nickel-magnesium intermediate alloy ingot.

[0040] The composition of the nickel-magnesium master alloy ingot prepared in this example was tested, and the results are shown in Table 2 below.

[0041] Table 2 Chemical composition of the nickel-magnesium master alloy ingot prepared in Example 2 (wt.%)

[0042] As can be seen from Table 2, the nickel-magnesium master alloy prepared in this embodiment contains very low levels of impurity elements, especially oxygen and nitrogen, which avoids affecting the cleanliness of downstream high-temperature alloys.

[0043] Example 3 The nickel-magnesium master alloy for high-temperature alloy of this embodiment is composed of the following elements in percentage by mass: 50% Mg, and the balance Ni and unavoidable impurities.

[0044] The method for preparing the nickel-magnesium master alloy for high-temperature alloy of the present embodiment comprises the following steps: Step 1: Select electrolytic nickel and magnesium ingots as raw materials, cut and grind the raw materials to remove surface oil and scale, calculate the ingredients according to the ratio of the target product nickel-magnesium master alloy for high-temperature alloy, and weigh and divide them into 26 kg plate-shaped electrolytic nickel and 25 kg magnesium ingot pieces; The electrolytic nickel meets the Ni9999 specification and composition requirements in GB / T 6516-2010 "Electrolytic Nickel", and the magnesium ingot meets the composition requirements of Mg9995 in GB / T 3499-2003 "Native Magnesium Ingot", and the magnesium ingot after cutting and grinding is a small block with a length, width and thickness of 10cm-15cm, 5cm-10cm and 3cm-5cm respectively, and the electrolytic nickel after cutting and grinding is a plate with a length, width and thickness of 3cm-5cm, 3cm-5cm and 0.5cm-1.5cm respectively; Step 2: Place the plate-shaped electrolytic nickel and magnesium ingot pieces weighed and packed in step 1 into a molybdenum crucible with a mass purity of 99.95% in an induction melting furnace, with the magnesium ingot pieces at the bottom and the plate-shaped electrolytic nickel at the top. Close the lid of the induction melting furnace and evacuate to a vacuum degree of 4.6×10 -1 Pa, and then start the heating power supply to heat and melt, using step-by-step power supply heating, respectively, at 20kW, 55kW, 85kW power for 15 minutes, when the power is maintained at 55kW, the raw material turns red and argon is filled to -0.05MPa, then the power is increased to 100kW until the raw material is completely melted, and then the power is reduced to 70kW and the melting is continued for 5 minutes to obtain an alloy melt in the crucible; Step 3: Start the steam filtration system of the induction melting furnace, pour the alloy melt in the crucible in step 2 into the cast iron ingot mold, open the furnace and take samples after cooling for 12 hours to obtain the nickel-magnesium intermediate alloy ingot, and then refine, screen, inspect and package the nickel-magnesium intermediate alloy ingot.

[0045] The composition of the nickel-magnesium intermediate alloy ingot prepared in this example was tested, and the results are shown in Table 3 below.

[0046] Table 3 Chemical composition of the nickel-magnesium master alloy ingot prepared in Example 3 (wt.%)

[0047] As can be seen from Table 3, the nickel-magnesium master alloy prepared in this embodiment contains very low levels of impurity elements, especially oxygen and nitrogen, which avoids affecting the cleanliness of downstream high-temperature alloys.

[0048] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a nickel-magnesium master alloy for high-temperature alloys, wherein the nickel-magnesium master alloy is composed of the following elements in percentage by mass: Mg4%~50%, the balance is Ni and inevitable impurities, characterized in that the method comprises the following steps: Step 1: Select electrolytic nickel and magnesium ingots as raw materials, cut and grind the raw materials, calculate the ingredients according to the ratio of nickel-magnesium master alloy for high-temperature alloy of the target product, and weigh and package them; Step 2: Put the weighed raw materials in step 1 into the crucible of the induction melting furnace, evacuate the furnace and heat it for melting. After the raw materials turn red, fill them with argon gas. After all the raw materials are melted, reduce the power by 10kW~30kW and continue melting for 5min~10min to obtain an alloy melt in the crucible. Step 3: Start the steam filtration system of the induction melting furnace, pour the alloy melt in the crucible in step 2 into the cast iron ingot mold, cool for 10h~12h, open the furnace and take samples to obtain the nickel-magnesium intermediate alloy ingot, and then refine, screen, inspect and package the nickel-magnesium intermediate alloy ingot.

2. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The unavoidable impurities include the following elements in mass percentage: Ag≤0.001%, Co≤0.01%, Fe≤0.1%, Mn≤0.05%, Cu≤0.003%, As≤0.002%, Sn≤0.001%, Zn≤0.002%, Si≤0.02%, P≤0.01%, C≤0.05%, S≤0.005%, O≤0.005%, and N≤0.007%.

3. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The electrolytic nickel in step 1 meets the Ni9999 specification and composition requirements in GB / T 6516-2010 "Electrolytic Nickel", and the magnesium ingot meets the composition requirements of Mg9995 in GB / T 3499-2003 "Native Magnesium Ingot".

4. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The length, width and thickness of the magnesium ingot after cutting and polishing in step 1 are 10cm~15cm, 5cm~10cm and 3cm~5cm respectively, and the length, width and thickness of the electrolytic nickel after cutting and polishing are 3cm~5cm, 3cm~5cm and 0.5cm~1.5cm respectively.

5. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The crucible in step 2 is a molybdenum crucible with a mass purity of 99.95%.

6. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The vacuum in step 2 is evacuated to a vacuum degree not exceeding 5×10 -1 Pa.

7. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: The power supply heating smelting mode described in step 2 is step-by-step power supply heating, which gradually adjusts and increases the smelting power and maintains it at each power for 10 minutes to 15 minutes.

8. The method for preparing a nickel-magnesium master alloy for high-temperature alloy according to claim 1, characterized in that: In step 2, after the raw material turns red, argon gas is added to -0.045MPa±0.005MPa.

9. The method for preparing a nickel-magnesium master alloy for high temperature alloy according to claim 1, characterized in that: The steam extraction system in step 3 comprises a condenser (2) arranged at the interface of the furnace body (1) of the induction melting furnace, a stacked water-cooling baffle (3) is arranged inside the condenser (2), and an oil pool filter (4) is arranged at the rear end of the condenser (2).

10. A nickel-magnesium master alloy for high temperature alloys, characterized in that it is prepared by the method described in any one of claims 1 to 9.

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