Preparation method and device of nickel-boron intermediate alloy for nickel-based superalloy

Abstract

The invention discloses a preparation method of a nickel-boron intermediate alloy for a nickel-based superalloy, which comprises the following steps: step 1, mixing boric anhydride powder and nickel protoxide powder, pressing to obtain a pre-combination reaction block, mixing metallic nickel and carbon powder, and pressing to obtain a thermal reduction reaction block; 2, the pre-combination reaction block is heated to be molten to obtain a molten product, then the molten product and the thermal reduction reaction block are mixed for a carbon thermal reduction reaction, and an alloy melt is obtained; 3, casting the alloy melt under a vacuum condition, and cooling to obtain a nickel-boron intermediate alloy; the invention further discloses a preparation device of the nickel-boron intermediate alloy for the nickel-based high-temperature alloy. According to the preparation method disclosed by the invention, the pre-chemical combination and carbon thermal reduction processes are adopted, so that the formation of a boron-rich phase is effectively inhibited, the fluctuation increase and non-uniform distribution of the boron element content are avoided, a guarantee is provided for the subsequent proportioning link of the nickel-based high-temperature alloy, and the preparation method is suitable for the technical field of intermediate alloy preparation.

Description

Technical Field

[0001] The present invention belongs to the technical field of master alloy preparation, and particularly relates to a preparation method and device for nickel-boron master alloy for nickel-based superalloys. Background Art

[0002] As a main grain boundary strengthening element in nickel-based superalloys, boron (B) effectively improves the plasticity of the alloy and inhibits the occurrence of phenomena such as hydrogen embrittlement by reducing the grain boundary energy and enhancing the grain boundary bonding strength. The appropriate addition of boron can increase the content of eutectic phase in the alloy and improve the high-temperature creep resistance of the alloy. However, the excessive addition of boron will lead to an excessive amount of eutectic phase precipitation, which may instead cause crack propagation and ultimately reduce the mechanical properties of the alloy. Therefore, the addition amount of boron in nickel-based superalloys is usually strictly controlled within the range of 0.012% - 0.06%. It should be noted that the melting point of elemental boron is as high as 2075°C, and the density is only 2.46 g / cm 3 , and there are significant differences in physical properties between it and the matrix nickel. During the melting process of nickel-based superalloys, if elemental boron is directly added, it is difficult to achieve uniform distribution of trace and low-density boron elements. Therefore, nickel-boron master alloy has become an important raw material form for introducing boron elements in existing nickel-based superalloys.

[0003] The metal thermal reduction method is the mainstream process for the preparation of nickel-boron master alloy at present. Among them, the reducing agent generally mainly uses aluminum or aluminum-magnesium alloy. However, when using aluminum or aluminum-magnesium alloy as the reducing agent, there are problems such as low boron reduction rate and the influence of aluminum residue on the alloy purity. To solve the problem of aluminum residue, the Chinese invention patent "A Production Method of Low-Aluminum and Low-Carbon Nickel-Boron Master Alloy" (Application No. 201110089199.6) effectively reduces the aluminum content and maintains the boron content by introducing slag refining technology, constructing a specific CaO-CaF2-SiO2-B2O3-NiO slag system, and combining a two-step melting process. However, this process flow is relatively complex and the production cost increases significantly. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a preparation method for nickel-boron master alloy for nickel-based superalloys. This preparation method pre-reacts boric anhydride powder and nickel oxide powder to prepare the Ni(BO2)2 intermediate phase, and then reduces the Ni(BO2)2 intermediate phase by carbothermal reduction to generate nickel-boron alloy, effectively inhibiting the formation of boron-rich phase, shortening the preparation process, and solving the problem of aluminum element residue caused by the aluminothermic reduction method in the prior art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a preparation method for nickel-boron master alloy for nickel-based superalloys, which includes the following steps: Step 1: Mix boric anhydride powder and nickel oxide powder and then press them to obtain a pre - compound reaction block. Mix metallic nickel and carbon powder and then press them to obtain a thermal reduction reaction block. Step 2: Heat the pre - compound reaction block obtained in Step 1 until it melts to obtain a molten product. Pre - heat and keep the thermal reduction reaction block obtained in Step 1 warm. Then mix the molten product with the thermal reduction reaction block to carry out a carbothermal reduction reaction to obtain an alloy melt. Step 3: Cast the alloy melt obtained in Step 2 under vacuum conditions and cool it to obtain a nickel - boron master alloy.

[0006] Since the existing metal thermal reduction process first reduces B2O3 to elemental boron. Once formed, this elemental boron, due to its physical properties of high melting point and low density, requires long - time smelting and forced stirring to dissolve or homogenize, and it is difficult to completely eliminate. However, the present invention adopts a pre - compound + carbothermal reduction process. Through the pre - combination of oxides, the formation of elemental boron is avoided from the source; the subsequent carbothermal reduction reaction directly generates the target NiB phase, so high - melting - point and low - density elemental boron will not be produced, and the formation of boron - rich phases is inhibited.

[0007] In the above - mentioned preparation method, the boric anhydride powder, nickel oxide powder, and carbon powder are dried before mixing, and the pressing is cold isostatic pressing.

[0008] In the above - mentioned preparation method, the pre - heating temperature in Step 2 is 1000℃ - 1100℃.

[0009] By pre - heating the thermal reduction reaction block, the present invention can reduce the temperature difference and prevent sputtering. Since the temperature range for the formation of Ni(BO2)2 phase from boric anhydride powder (B2O3) and nickel oxide (NiO) powder in the pre - compound step is 800℃ - 950℃, to ensure that this product is in a completely molten state for subsequent mixing, its temperature needs to be controlled above 1000℃. By controlling the pre - heating temperature of the thermal reduction reaction block at 1000℃ - 1100℃, the temperature difference between it and the high - temperature molten product can be reduced, thus avoiding safety hazards such as melt sputtering caused by too large a temperature difference when the two are mixed. In addition, pre - heating the thermal reduction reaction block can also improve the chemical reactivity of each component, which helps to accelerate the subsequent carbothermal reduction reaction process and thus shorten the total reaction time.

[0010] In the above - mentioned preparation method, the process of the carbothermal reduction reaction in Step 2 is: under the condition that the vacuum degree is lower than 5×10 -3 Pa and argon gas is continuously introduced, heat up to 1550℃ - 1600℃ and keep it warm until both the molten product and the thermal reduction reaction block are completely melted and there are no bubbles generated.

[0011] The present invention controls the vacuum degree to be lower than 5×10 -3Pa and continuously introduce argon gas, and timely discharge the generated carbon monoxide gas to effectively reduce the oxygen partial pressure and carbon monoxide partial pressure in the environment, so as to promote the carbothermal reduction reaction and improve the reduction rate of boron; and optimize and set the temperature to 1550 °C to 1600 °C through the oxide oxygen potential diagram as shown in Figure 1 to ensure that the carbothermal reduction reaction occurs between the pre-compounded Ni(BO2)2 and the carbon powder, generating the NiB phase, so that the matrix nickel melt can be fully mixed and reacted with the NiB phase to form a uniform nickel-boron master alloy; through the reaction until no bubbles are produced to ensure that the carbothermal reduction reaction is completed and the generated carbon monoxide is completely discharged.

[0012] In the above preparation method, before casting in step three, the alloy melt is cooled to 1200 °C to 1300 °C and kept warm.

[0013] In the present invention, by keeping the alloy melt at 1200 °C to 1300 °C before pouring, it is used to achieve the homogenization of the temperature and composition of the alloy melt.

[0014] In the above preparation method, the nickel-boron master alloy in step three is composed of the following components by mass content: B 3% to 15%, and the balance is Ni and inevitable impurity elements; the mass content of the inevitable impurity elements is: Fe not more than 0.75%, Al not more than 0.01%, Si not more than 0.60%, C not more than 0.02%, Cu not more than 0.05%, Co not more than 0.10%, N not more than 0.01%, O not more than 0.05%.

[0015] In the present invention, according to the Ni-B binary alloy calculation phase diagram as shown in Figure 2 the mass content of boron element is set to 3% to 15%, and this mass content can effectively avoid the formation of boron-rich phases and avoid the fluctuation of boron element caused by the generated boron-rich phases.

[0016] The present invention also discloses a device applied to the above preparation method, including a pre-compounding chamber and a thermal reduction chamber that are interconnected. Both the pre-compounding chamber and the thermal reduction chamber are connected to a gas supply and vacuum system. A reaction mechanism is arranged in the pre-compounding chamber, and an induction melting device and a casting mold are arranged in the thermal reduction chamber. A support and tilting mechanism is arranged on the induction melting device.

[0017] In the above device, a gate is arranged at the connection between the pre-compounding chamber and the thermal reduction chamber. The outer shell of the pre-compounding chamber is composed of a cold-rolled steel plate layer and a refractory brick layer, and the outer shell of the thermal reduction chamber is composed of a double-layer water-cooled jacket layer and a refractory brick layer.

[0018] In the above device, a chute is arranged between the induction melting device and the casting mold, and a porous ceramic filter screen arranged in a staggered manner is arranged on the chute.

[0019] The above-mentioned device, wherein the reaction mechanism is a reaction diversion groove, the reaction diversion groove includes a top platform area, an intermediate reaction diversion area and a bottom channel area, and heating coils are installed in both the top platform area and the intermediate reaction diversion area.

[0020] The present invention has the following advantages compared with the prior art: 1. By adopting the pre-combination + carbothermal reduction process, the present invention effectively inhibits the formation of boron-rich phases, avoids the increase in the volatility of boron element content and uneven distribution, provides guarantee for the subsequent batching process of nickel-based superalloys, and shortens the preparation process; at the same time, compared with the prior art of using aluminum or aluminum-magnesium alloy reductants to prepare nickel-boron master alloy, the pre-combination + carbothermal reduction process eliminates the hidden danger of aluminum element residue, improves the purity of nickel-boron master alloy, and reduces the production cost.

[0021] 2. By preheating the carbothermal reduction reaction block, the present invention can reduce the temperature difference between the carbothermal reduction reaction block and the pre-combined molten product, prevent sputtering, and make the carbothermal reduction reaction block be pre-activated at high temperature, which can effectively catalyze the carbothermal reduction reaction of Ni(BO2)2 at high temperature, significantly improve the efficiency of the carbothermal reduction reaction, and thus shorten the preparation cycle.

[0022] 3. By setting the double-chamber structure of the pre-combination chamber and the carbothermal reduction chamber, the present invention can achieve independent and precise control of the environment of each chamber for different processes in the preparation process of nickel-boron alloy, so that each process can be carried out under the best environmental conditions, thereby effectively improving the reaction efficiency and product purity, reducing the risk of cross-contamination between different processes, and enhancing the flexibility of the process.

[0023] 4. By setting an induction melting device in the carbothermal reduction chamber and combining with a porous ceramic filter on the chute, the present invention uses the forced stirring effect of the induction melting device and the porous ceramic filter during the melting and casting processes to ensure the uniformity of the distribution of alloy elements and inhibit segregation.

[0024] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is an oxygen potential diagram of oxides.

[0026] Figure 2 is a calculated phase diagram of Ni-B binary alloy.

[0027] Figure 3 is a boron element distribution diagram of the nickel-boron master alloy in Example 1 of the present invention.

[0028] Figure 4 is a result schematic diagram of the nickel-boron master alloy preparation device of the present invention.

[0029] Description of the reference numerals: 1 - pre - compounding chamber; 2 - thermal reduction chamber; 3 - reaction diversion chute; 4 - heating coil; 5 - induction melting equipment; 6 - support and tilting mechanism; 7 - chute; 8 - casting mold; 9 - feeding bin. Detailed implementation mode

[0030] The preparation method of the nickel - boron master alloy for nickel - based superalloys of the present invention is described in detail through Examples 1 - 3.

[0031] Example 1 The preparation method of this example includes the following steps: Step 1: Boron anhydride powder with an average particle size of 80 µm and a mass purity of not less than 99%, nickel oxide powder with an average particle size of 15 µm and a mass purity of not less than 99%, nickel beans with an average particle size of 3 mm and a mass purity of not less than 99%, and carbon powder with an average particle size of 0.5 mm and a mass purity of not less than 99.9% are all dried at 150 °C for 10 h. Then, boron anhydride powder and nickel oxide powder with a mass ratio of 52:48 and absolute ethanol are placed in a double - motion mixer and mixed at a speed of 20 r / min for 2 h, and then cold isostatically pressed at a pressure of 250 MPa for 15 min to obtain a pre - compounding reaction block; the nickel beans are pickled and ultrasonically cleaned with deionized water before drying, and the mass of the absolute ethanol is 0.5% of the total mass of the boron anhydride powder and nickel oxide powder; Nickel beans and carbon powder with a mass ratio of 57:43 are placed in a double - motion mixer, mixed at a speed of 10 r / min for 30 min, and then cold isostatically pressed at a pressure of 250 MPa for 15 min to obtain a thermal reduction reaction block; Step 2: In an environment with a vacuum degree lower than 5×10 -3 Pa, the pre - compounding reaction block obtained in Step 1 is heated to 800 °C, and then heated to 1000 °C to obtain a molten product. The thermal reduction reaction block obtained in Step 1 is pre - heated and kept warm at 1000 °C. Then, the molten product and the thermal reduction reaction block are mixed, and under the condition of a vacuum degree lower than 5×10 -3 Pa and continuous argon injection, it is heated to 1550 °C - 1600 °C for carbothermal reduction reaction, and kept warm until both the molten product and the thermal reduction reaction block are completely melted and there are no bubbles generated to obtain an alloy melt; the mass ratio of the pre - compounding reaction block to the thermal reduction reaction block is 56:43; Step 3: The alloy melt obtained in Step 2 is cooled to 1200 °C - 1300 °C and kept warm for 10 min, and then cast under vacuum conditions. After cooling, a Ni - 15B nickel - boron master alloy is obtained, and the Ni - 15B nickel - boron master alloy is sand - blasted, crushed, and screened.

[0032] The Ni-15B nickel-boron master alloy prepared in this example was subjected to compositional analysis, and the results are shown in Table 1.

[0033] Table 1 Element mass content of Ni-15B master alloy (%)

[0034] As can be seen from Table 1, the nickel-boron master alloy prepared in this example can precisely control the contents of nickel and boron elements, significantly reduce the contents of aluminum element and impurity elements, thereby ensuring the high purity of the nickel-boron master alloy.

[0035] The boron element distribution of the Ni-15B nickel-boron master alloy prepared in this example was tested, and the results are as Figure 3 shown. The uniformity of the boron element distribution has been significantly improved, and the degree of distribution difference has been significantly weakened, indicating that the preparation method of this example can prepare a nickel-boron master alloy with low impurity content and uniform element distribution.

[0036] Example 2 The preparation method of this example includes the following steps: Step 1: Boron anhydride powder with an average particle size of 80 µm and a mass purity of not less than 99%, nickel oxide powder with an average particle size of 15 µm and a mass purity of not less than 99%, nickel beans with an average particle size of 3 mm and a mass purity of not less than 99%, and carbon powder with an average particle size of 0.5 mm and a mass purity of not less than 99.9% were all dried at 150 °C for 10 h. Then, boron anhydride powder and nickel oxide powder with a mass ratio of 52:48 and absolute ethanol were placed in a double-motion mixer and mixed at a rotation speed of 20 r / min for 2 h, and then cold isostatically pressed at a pressure of 250 MPa for 15 min to obtain a pre-compound reaction block; the nickel beans were pickled and ultrasonically cleaned with deionized water before drying, and the mass of the absolute ethanol was 0.5% of the total mass of the boron anhydride powder and nickel oxide powder; Nickel beans and carbon powder with a mass ratio of 73:27 were placed in a double-motion mixer and mixed at a rotation speed of 10 r / min for 30 min, and then cold isostatically pressed at a pressure of 250 MPa for 15 min to obtain a thermal reduction reaction block; Step 2: In an environment with a vacuum degree lower than 5×10 -3 Pa, the pre-compound reaction block obtained in Step 1 was heated to 800 °C, and then heated to 1000 °C to obtain a molten product. The thermal reduction reaction block obtained in Step 1 was preheated and kept warm at 1050 °C. Then, the molten product was mixed with the thermal reduction reaction block, and in an environment with a vacuum degree lower than 5×10 -3Under the condition of continuously introducing argon and maintaining the presence of Pa, the temperature is raised to 1550 °C to 1600 °C for carbothermal reduction reaction, and the temperature is maintained until both the molten product and the hot reduction reaction mass are completely melted and no bubbles are generated, obtaining an alloy melt; the mass ratio of the pre-compounded reaction mass to the hot reduction reaction mass is 44:56; Step 3: Cool the alloy melt obtained in Step 2 to 1200 °C to 1300 °C and hold for 10 min, then cast under vacuum conditions, and after cooling, obtain Ni-10B nickel-boron master alloy. Carry out sandblasting, crushing, and screening on the Ni-10B nickel-boron master alloy.

[0037] Perform component analysis on the Ni-10B nickel-boron master alloy prepared in this example, and the results are shown in Table 2.

[0038] Table 2 Element mass content of Ni-10B master alloy (%)

[0039] As can be seen from Table 2, the nickel-boron master alloy prepared in this example can accurately control the contents of nickel and boron elements, significantly reduce the contents of aluminum element and impurity elements, thereby ensuring the high purity of the nickel-boron master alloy.

[0040] Example 3 The preparation method of this example includes the following steps: Step 1: Dry boric anhydride powder with an average particle size of 80 µm and a mass purity of not less than 99%, nickel oxide powder with an average particle size of 15 µm and a mass purity of not less than 99%, nickel beans with an average particle size of 3 mm and a mass purity of not less than 99%, and carbon powder with an average particle size of 0.5 mm and a mass purity of not less than 99.9% at 150 °C for 10 h. Then, place boric anhydride powder and nickel oxide powder with a mass ratio of 52:48 and absolute ethanol in a double-motion mixer, mix at a rotation speed of 20 r / min for 2 h, and then perform cold isostatic pressing at 250 MPa for 15 min to obtain a pre-compounded reaction mass; the nickel beans are pickled and ultrasonically cleaned with deionized water before drying, and the mass of the absolute ethanol is 0.5% of the total mass of the boric anhydride powder and nickel oxide powder; Place nickel beans and carbon powder with a mass ratio of 93:7 in a double-motion mixer, mix at a rotation speed of 10 r / min for 30 min, and then perform cold isostatic pressing at 250 MPa for 15 min to obtain a hot reduction reaction mass; Step 2: In an environment with a vacuum degree lower than 5×10 -3 Pa, heat the pre-compounded reaction mass obtained in Step 1 to 800 °C, then heat it to 1000 °C to obtain a molten product, and preheat and hold the hot reduction reaction mass obtained in Step 1 at 1100 °C. Then, after mixing the molten product and the hot reduction reaction mass, in a vacuum degree lower than 5×10 -3Under the condition of continuously introducing argon and maintaining the presence of Pa, the temperature is raised to 1550 °C to 1600 °C for carbothermal reduction reaction, and the temperature is maintained until both the molten product and the hot reduction reaction mass are completely melted and no bubbles are generated, obtaining an alloy melt; the mass ratio of the pre-combination reaction mass to the hot reduction reaction mass is 18:82; Step 3: Cool the alloy melt obtained in Step 2 to 1200 °C to 1300 °C and hold for 10 min, then cast under vacuum conditions. After cooling, a Ni-3B nickel-boron master alloy is obtained, and the Ni-3B nickel-boron master alloy is subjected to sandblasting, crushing, and screening.

[0041] The composition analysis of the Ni-3B nickel-boron master alloy prepared in this example is shown in Table 3.

[0042] Table 3 Element mass content of Ni-3B master alloy (%)

[0043] As can be seen from Table 3, the nickel-boron master alloy prepared in this example can accurately control the contents of nickel and boron elements, significantly reduce the contents of aluminum elements and impurity elements, thereby ensuring the high purity of the nickel-boron master alloy.

[0044] The preparation device of the nickel-boron master alloy for nickel-based superalloys of the present invention is described in detail through Example 4.

[0045] Example 4 As Figure 4 shown, the device of this example includes a pre-combination chamber 1 and a hot reduction chamber 2 that are interconnected. The pre-combination chamber 1 and the hot reduction chamber 2 are both connected to a gas supply and vacuum system. A reaction mechanism is provided in the pre-combination chamber 1, and an induction melting device 5 and a casting mold 8 are provided in the hot reduction chamber 2. A support and tilting mechanism 6 is provided on the induction melting device 5.

[0046] In actual use, in this example, by providing a pre-combination chamber 1 and a hot reduction chamber 2 that are interconnected, it is used to send the molten product obtained in the pre-combination chamber 1 into the hot reduction chamber 2 to prepare an alloy; by connecting the gas supply and vacuum system, it is used to regulate the air pressure and atmosphere in the pre-combination chamber 1 and the hot reduction chamber 2; by providing a reaction mechanism for pre-combination; by providing an induction melting device 5 for preparing an alloy melt, by providing a casting mold 8 for cooling and forming the alloy, and by providing a support and tilting mechanism 6 on the induction melting device 5 for injecting the alloy melt into the casting mold 8.

[0047] It should be noted that in this example, the support and tilting mechanism 6 is controlled by an experienced operator. By precisely adjusting the tilting angle and speed, it is ensured that the alloy melt can be completely and stably injected into the casting mold 8.

[0048] Further, as Figure 4 shown, in this embodiment, a gate is provided at the connection between the pre-combination chamber 1 and the thermal reduction chamber 2. The outer shell of the pre-combination chamber 1 is composed of a cold-rolled steel plate layer and a refractory brick layer, and the outer shell of the thermal reduction chamber 2 is composed of a double-layer water-cooled jacket layer and a refractory brick layer.

[0049] In actual use, in this embodiment, by providing a gate at the connection between the pre-combination chamber 1 and the thermal reduction chamber 2, it is used to seal the pre-combination chamber 1 and the thermal reduction chamber 2 respectively, independently adjust the atmosphere and air pressure, and reduce the risk of cross-contamination between different processes; the outer part of the outer shell of the pre-combination chamber 1 uses a cold-rolled steel plate layer and a refractory brick layer is built inside, which can insulate heat and prevent the erosion of the cold-rolled steel plate layer by the high-temperature melt; by using a double-layer water-cooled jacket layer and a refractory brick layer to form the outer shell of the thermal reduction chamber 2, it is used to cool the outer shell of the thermal reduction chamber 2; preferably, in this embodiment, the circulating water uses cooling water that is not prone to scale formation to reduce the descaling frequency.

[0050] Further, as Figure 4 shown, in this embodiment, a chute 7 is provided between the induction melting equipment 5 and the casting mold 8, and a porous ceramic filter screen arranged in a staggered manner is installed on the chute 7.

[0051] In actual use, in this embodiment, by providing a chute 7 between the induction melting equipment 5 and the casting mold 8, the alloy melt can be accurately injected into the casting mold 8; by providing a porous ceramic filter screen arranged in a staggered manner on the alumina layer, inclusions in the molten metal are filtered, and a stirring effect is generated on the molten metal to improve the element uniformity of the molten metal; preferably, in this embodiment, the chute 7 is composed of a steel shell layer, a refractory brick layer located above the steel shell layer, and an alumina layer located above the refractory brick layer, so that the chute 7 has excellent thermal stability to ensure that it can effectively resist the erosion of high-temperature molten metal; the pore size of the porous ceramic filter screen is 30PPI to achieve effective filtration of inclusions in the molten metal.

[0052] Further, as Figure 4 shown, in this embodiment, the reaction mechanism is a reaction diversion groove 3. The reaction diversion groove 3 includes a top platform area, an intermediate reaction diversion area, and a bottom channel area, and heating coils 4 are installed in both the top platform area and the intermediate reaction diversion area.

[0053] In actual use, in this embodiment, a top platform area is provided for pre - compounding, an intermediate reaction diversion area is provided for controlling the flow direction of the pre - compounded product flow, and it enters the induction melting equipment 5 through the bottom channel area; preferably, in this embodiment, the top platform area is inclined at 10°. While ensuring that the materials can be placed stably, the melted materials automatically flow to the intermediate reaction diversion area under the action of gravity and finally enter the thermal reduction chamber 2 through the bottom channel area; a heating coil 4 is installed in the top platform area to provide temperature conditions for pre - compounding, and a heating coil 4 is installed in the intermediate reaction diversion area to prevent the temperature of the melted materials from dropping and to make the material temperature uniform.

[0054] Preferably, in this embodiment, feeding bins 9 are provided at the tops of both the pre - compounding chamber 1 and the thermal reduction chamber 2 for feeding raw materials into the reaction diversion groove 3 and the induction melting equipment 5 respectively.

[0055] The usage method of the preparation device of the present invention is as follows: Place the pre - compounding reaction block on the top platform area of the reaction diversion groove 3 through the feeding bin 9 at the top of the pre - compounding chamber 1, turn on the gas supply, vacuum system and heating coil 4 for pre - compounding. The formed molten product enters the induction melting equipment 5 along the intermediate reaction diversion area and the bottom channel area; place the thermal reduction reaction block in the induction melting equipment 5 through the feeding bin 9 at the top of the thermal reduction chamber 2, turn on the gas supply and vacuum system and then carry out pre - heating and heat preservation. When the molten product enters the induction melting equipment 5, raise the temperature to carry out carbothermal reduction to obtain an alloy melt; then pour the alloy melt into the casting mold 8 through the chute 7 and obtain the alloy after cooling.

[0056] The above - mentioned are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes and equivalent structural transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a nickel-boron master alloy for a nickel-based high-temperature alloy, characterized in that: The preparation method comprises the following steps: Step 1: Mix boric anhydride powder and nickelous oxide powder and press them to obtain a pre-combination reaction block, and mix metallic nickel and carbon powder and press them to obtain a thermal reduction reaction block; Step 2: heating the pre-combination reaction block obtained in step 1 until it melts to obtain a molten product, and preheating and keeping the thermal reduction reaction block obtained in step 1, and then mixing the molten product with the thermal reduction reaction block to perform a carbothermal reduction reaction to obtain an alloy melt; Step 3: Casting the alloy melt obtained in step 2 under vacuum conditions, and obtaining a nickel-boron master alloy after cooling.

2. The preparation method according to claim 1, characterized in that: In step 1, the boric anhydride powder, nickelous oxide powder and carbon powder are dried before mixing, and the pressing is cold isostatic pressing.

3. The preparation method according to claim 1, characterized in that: The preheating temperature in step 2 is 1000°C to 1100°C.

4. The preparation method according to claim 1, characterized in that: The process of the carbon thermal reduction reaction in step 2 is: -3 Pa and continuously introducing argon, the temperature is raised to 1550° C.-1600° C., and the temperature is maintained until the molten product and the thermal reduction reaction block are completely melted and no bubbles are generated.

5. The preparation method according to claim 1, characterized in that: In step 3, the alloy melt is cooled to 1200° C. to 1300° C. and kept warm before casting.

6. The preparation method according to claim 1, characterized in that: The nickel-boron master alloy in step 3 is composed of the following components by mass content: B 3%~15%, the balance is Ni and inevitable impurity elements; the mass content of the inevitable impurity elements is: Fe not more than 0.75%, Al not more than 0.01%, Si not more than 0.60%, C not more than 0.02%, Cu not more than 0.05%, Co not more than 0.10%, N not more than 0.01%, O not more than 0.05%.

7. A device applied to the preparation method according to any one of claims 1 to 6, characterized in that: The invention comprises a pre-combination chamber (1) and a thermal reduction chamber (2) which are interconnected, wherein the pre-combination chamber (1) and the thermal reduction chamber (2) are both connected to a gas supply and vacuum system, a reaction mechanism is arranged in the pre-combination chamber (1), an induction melting device (5) and a casting mold (8) are arranged in the thermal reduction chamber (2), and a support and dumping mechanism (6) is arranged on the induction melting device (5).

8. The device according to claim 7, characterized in that A gate is provided at the connection point between the pre-combination chamber (1) and the thermal reduction chamber (2); the outer shell of the pre-combination chamber (1) is composed of a cold-rolled steel plate layer and a refractory brick layer, and the outer shell of the thermal reduction chamber (2) is composed of a double-layer water-cooled jacket layer and a refractory brick layer.

9. The device according to claim 7, characterized in that A chute (7) is provided between the induction melting equipment (5) and the casting mold (8), and a staggered porous ceramic filter screen is installed on the chute (7).

10. The device according to claim 7, characterized in that The reaction mechanism is a reaction guide groove (3), the reaction guide groove (3) comprising a top platform area, a middle reaction guide area and a bottom channel area, and the top platform area and the middle reaction guide area are both equipped with heating coils (4).

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