Preparation method and device for nickel-boron master alloy for nickel-based superalloy

Abstract

The present invention discloses a preparation method of nickel-boron master alloy for nickel-based superalloys. The preparation method comprises the following steps: Step 1, mixing boric anhydride powder and nickel oxide powder and then pressing to obtain a pre-combination reaction block, and mixing metallic nickel and carbon powder and then pressing to obtain a thermal reduction reaction block; Step 2, heating the pre-combination reaction block to melting to obtain a molten product, and then mixing the molten product with the thermal reduction reaction block to carry out a carbothermal reduction reaction to obtain an alloy melt; Step 3, casting the alloy melt under vacuum conditions and cooling to obtain the nickel-boron master alloy. The present invention also discloses a preparation device of nickel-boron master alloy for nickel-based superalloys. The preparation method of the present invention effectively inhibits the formation of boron-rich phases by adopting the pre-combination + carbothermal reduction process, avoids the increase in the volatility of boron element content and uneven distribution, provides a guarantee for the subsequent batching process of nickel-based superalloys, and is applicable to the technical field of master 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) element 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 too much precipitation of eutectic phase, 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 added directly in the form of elemental boron, 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 number 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 existing technologies 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 existing technology.

[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:

[0006] Step 1: Mix boric anhydride powder and nickel oxide powder and then press them to obtain a pre-combination reaction block. Mix metallic nickel and carbon powder and then press them to obtain a thermal reduction reaction block.

[0007] Step 2: Heat the pre-combination reaction block obtained in Step 1 to melting to obtain a molten product, and preheat and keep warm the thermal reduction reaction block obtained in Step 1. Then, mix the molten product with the thermal reduction reaction block to carry out a carbothermal reduction reaction to obtain an alloy melt.

[0008] Step 3: Cast the alloy melt obtained in Step 2 under vacuum conditions and cool it to obtain a nickel boride master alloy.

[0009] 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-term melting and forced stirring to dissolve or homogenize, and it is difficult to completely eliminate. The present invention adopts a pre-combination + carbothermal reduction process. Through the pre-combination of oxides, the formation of elemental boron is avoided at 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.

[0010] In the above preparation method, the boric anhydride powder, nickel oxide powder, and carbon powder are dried before mixing, and the pressing is cold isostatic pressing.

[0011] In the above preparation method, the preheating temperature in Step 2 is 1000°C to 1100°C.

[0012] By preheating the thermal reduction reaction block, the present invention can reduce the temperature difference and prevent sputtering. Since the temperature range for generating the Ni(BO2)2 phase from boric anhydride powder (B2O3) and nickel oxide (NiO) powder in the pre-combination step is 800°C to 950°C, to ensure that this product is in a completely molten state for subsequent mixing, its temperature needs to be controlled above 1000°C. By controlling the preheating temperature of the thermal reduction reaction block at 1000°C to 1100°C, the temperature difference between it and the high-temperature molten product can be reduced, thereby avoiding safety hazards such as melt sputtering caused by too large a temperature difference when the two are mixed. In addition, preheating 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.

[0013] In the above preparation method, the process of the carbothermal reduction reaction in Step 2 is as follows: Under the condition that the vacuum degree is lower than 5×10 -3 Pa and argon is continuously introduced, heat up to 1550°C to 1600°C and keep warm until both the molten product and the thermal reduction reaction block are completely melted and there are no bubbles generated.

[0014] The present invention controls the vacuum degree to be lower than 5×10 -3 Pa and continuously introduces argon gas, and timely discharges the generated carbon monoxide gas, effectively reducing the oxygen partial pressure and carbon monoxide partial pressure in the environment to promote the carbothermal reduction reaction and improve the reduction rate of boron; and optimizes and sets 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 to generate the NiB phase, enabling the matrix nickel melt to be fully mixed and reacted with the NiB phase to form a uniform nickel-boron master alloy; by reacting until no bubbles are produced to ensure that the carbothermal reduction reaction is completed and the generated carbon monoxide is completely discharged.

[0015] In the above preparation method, before casting in step three, the alloy melt is cooled to 1200°C to 1300°C and held.

[0016] The present invention holds the alloy melt at 1200°C to 1300°C before casting to achieve the homogenization of the temperature and composition of the alloy melt.

[0017] 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%.

[0018] The present invention calculates the phase diagram according to the Ni-B binary alloy phase diagram as shown in Figure 2 and sets the mass content of the boron element to 3% to 15%, and this mass content can effectively avoid the formation of boron-rich phases and avoid the fluctuation of boron elements caused by the generated boron-rich phases.

[0019] 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. The pre-compounding chamber and the thermal reduction chamber are both 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.

[0020] 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.

[0021] In the above-mentioned device, a chute is provided between the induction melting equipment and the casting mold, and a porous ceramic filter screen arranged in a staggered manner is provided on the chute.

[0022] In the above-mentioned device, the reaction mechanism is a reaction diversion chute, and the reaction diversion chute 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.

[0023] The present invention has the following advantages compared with the prior art:

[0024] 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.

[0025] 2. By preheating the carbothermal reduction reaction mass, the present invention can reduce the temperature difference between the carbothermal reduction reaction mass and the pre-combined molten product, prevent sputtering, and make the carbothermal reduction reaction mass 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 further shorten the preparation cycle.

[0026] 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.

[0027] 4. By setting an induction melting equipment in the carbothermal reduction chamber and combining with setting a porous ceramic filter screen on the chute, the present invention uses the forced stirring action of the induction melting equipment and the porous ceramic filter screen during the melting and casting processes to ensure the uniformity of the distribution of alloy elements and inhibit segregation.

[0028] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an oxygen potential diagram of oxides.

[0030] Figure 2 is a calculated phase diagram of Ni-B binary alloy.

[0031] Figure 3This is the boron element distribution map of the nickel-boron master alloy in Embodiment 1 of the present invention.

[0032] Figure 4 This is the result schematic diagram of the preparation device for the nickel-boron master alloy of the present invention.

[0033] Explanation of reference numerals:

[0034] 1 - Pre-compounding chamber; 2 - Thermal reduction chamber; 3 - Reaction diversion trough; 4 - Heating coil; 5 - Induction melting equipment; 6 - Support and tilting mechanism; 7 - Chute; 8 - Casting mold; 9 - Feeding bin. Detailed implementation mode

[0035] The preparation method of the nickel-boron master alloy for nickel-based superalloys of the present invention is described in detail through Embodiments 1 to 3.

[0036] Embodiment 1

[0037] The preparation method of this embodiment includes the following steps:

[0038] 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;

[0039] Nickel beans and carbon powder with a mass ratio of 57:43 are placed in a double-motion mixer and 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;

[0040] 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 preheated and kept warm at 1000 °C. Then, the molten product and the thermal reduction reaction block are mixed, and in an environment with a vacuum degree lower than 5×10 -3Under the condition of continuously introducing argon and maintaining Pa, the temperature is raised to 1550 °C - 1600 °C for carbothermal reduction reaction, and the temperature is maintained until both the molten product and the thermally reduced 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 thermally reduced reaction mass is 56:43;

[0041] Step 3: Cool the alloy melt obtained in Step 2 to 1200 °C - 1300 °C and hold for 10 min, then cast under vacuum conditions, and after cooling, obtain a Ni-15B nickel-boron master alloy. Perform sandblasting, crushing, and screening on the Ni-15B nickel-boron master alloy.

[0042] Perform component analysis on the Ni-15B nickel-boron master alloy prepared in this example, and the results are shown in Table 1.

[0043] Table 1 Element mass content (%) of Ni-15B master alloy

[0044]

[0045] As can be seen from Table 1, 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.

[0046] Perform boron element distribution test on the Ni-15B nickel-boron master alloy prepared in this example, and the results are as Figure 3 shown. The uniformity of 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.

[0047] Example 2

[0048] The preparation method of this example includes the following steps:

[0049] 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, nickel oxide powder, and absolute ethanol with a mass ratio of 52:48 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 the nickel oxide powder;

[0050] Put nickel beans and carbon powder with a mass ratio of 73:27 into a double-motion mixer, mix at a speed of 10 r / min for 30 min, and then perform cold isostatic pressing at a pressure of 250 MPa for 15 min to obtain a thermal reduction reaction block;

[0051] Step 2: In an environment with a vacuum degree lower than 5×10 -3 Pa, heat the pre-compounded reaction block obtained in Step 1 to 800 °C, and then heat it to 1000 °C to obtain a molten product. Preheat and keep the thermal reduction reaction block obtained in Step 1 at 1050 °C. Then, after mixing the molten product and the thermal reduction reaction block, under the condition of a vacuum degree lower than 5×10 -3 Pa and continuously introducing argon, heat it to 1550 °C - 1600 °C for carbothermal reduction reaction, and keep the temperature until both the molten product and the thermal reduction reaction block are completely melted and no bubbles are generated to obtain an alloy melt; the mass ratio of the pre-compounded reaction block to the thermal reduction reaction block is 44:56;

[0052] Step 3: Cool the alloy melt obtained in Step 2 to 1200 °C - 1300 °C and keep it warm for 10 min, then cast it under vacuum conditions. After cooling, obtain Ni-10B nickel-boron master alloy, and perform sandblasting, crushing, and screening on the Ni-10B nickel-boron master alloy.

[0053] Perform composition analysis on the Ni-10B nickel-boron master alloy prepared in this example, and the results are shown in Table 2.

[0054] Table 2 Element mass content of Ni-10B master alloy (%)

[0055]

[0056] 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 elements and impurity elements, thereby ensuring the high purity of the nickel-boron master alloy.

[0057] Example 3

[0058] The preparation method of this example includes the following steps:

[0059] 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, nickel oxide powder, and absolute ethanol with a mass ratio of 52:48 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-combination 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;

[0060] Nickel beans and carbon powder with a mass ratio of 93:7 are placed in a double-motion mixer and 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;

[0061] Step 2: In an environment with a vacuum degree lower than 5×10 -3 Pa, the pre-combination 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 preheated and kept warm at 1100 °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 no bubbles are generated to obtain an alloy melt; the mass ratio of the pre-combination reaction block to the thermal reduction reaction block is 18:82;

[0062] 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-3B nickel-boron master alloy is obtained, and the Ni-3B nickel-boron master alloy is sandblasted, crushed, and screened.

[0063] The composition analysis of the Ni-3B nickel-boron master alloy prepared in this example is shown in Table 3.

[0064] Table 3 Element mass content (%) of Ni-3B master alloy

[0065]

[0066] 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.

[0067] The preparation device of nickel-boron master alloy for nickel-based superalloys of the present invention is described in detail through Example 4.

[0068] Example 4

[0069] As Figure 4 shown, the device of this embodiment includes a pre-combination chamber 1 and a thermal reduction chamber 2 that are interconnected. Both the pre-combination chamber 1 and the thermal reduction chamber 2 are connected to a gas supply and vacuum system. A reaction mechanism is provided inside the pre-combination chamber 1, and an induction melting device 5 and a casting mold 8 are provided inside the thermal reduction chamber 2. A support and tilting mechanism 6 is provided on the induction melting device 5.

[0070] In actual use, in this embodiment, by providing a pre-combination chamber 1 and a thermal reduction chamber 2 that are interconnected, it is used to send the molten product obtained in the pre-combination chamber 1 into the thermal reduction chamber 2 to prepare the alloy; by connecting the gas supply and vacuum system, it is used to regulate the air pressure and atmosphere inside the pre-combination chamber 1 and the thermal reduction chamber 2; by providing a reaction mechanism for pre-combination; by providing an induction melting device 5 for preparing the 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.

[0071] It should be noted that in this embodiment, 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.

[0072] Furthermore, 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.

[0073] 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 regulate 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 the inside is lined with a refractory brick layer, 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 forming scale layers to reduce the frequency of descaling.

[0074] Furthermore, as Figure 4 shown, in this embodiment, a chute 7 is provided between the induction melting device 5 and the casting mold 8, and a porous ceramic filter screen arranged in a staggered manner is installed on the chute 7.

[0075] In actual use, in this embodiment, a chute 7 is arranged between the induction melting equipment 5 and the casting mold 8 to accurately inject the alloy melt into the casting mold 8; by arranging a porous ceramic filter screen with staggered arrangement on the alumina layer, inclusions in the molten metal are filtered, and the molten metal is agitated 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 effectively filter inclusions in the molten metal.

[0076] Furthermore, as Figure 4 shown, in this embodiment, the reaction mechanism is a reaction diversion chute 3, and the reaction diversion chute 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.

[0077] In actual use, in this embodiment, the top platform area is provided for pre-combination, the intermediate reaction diversion area is provided for controlling the flow direction of the pre-combination product, 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; by installing a heating coil 4 in the top platform area to provide temperature conditions for pre-combination, and by installing a heating coil 4 in the intermediate reaction diversion area to prevent the temperature of the melted materials from dropping and to make the material temperature uniform.

[0078] Preferably, in this embodiment, charging bins 9 are provided at the tops of both the pre-combination chamber 1 and the thermal reduction chamber 2 for feeding raw materials into the reaction diversion chute 3 and the induction melting equipment 5 respectively.

[0079] The usage method of the preparation device of the present invention is as follows: place the pre-combination reaction block on the top platform area of the reaction diversion chute 3 through the charging bin 9 at the top of the pre-combination chamber 1, turn on the gas supply, vacuum system, and heating coil 4 for pre-combination, and 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 charging bin 9 at the top of the thermal reduction chamber 2, turn on the gas supply and vacuum system and then carry out preheating and heat preservation, and when the molten product enters the induction melting equipment 5, raise the temperature for carbothermal reduction to obtain an alloy melt; then inject the alloy melt into the casting mold 8 through the chute 7, and an alloy is obtained after cooling.

[0080] The above 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 based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A preparation method of nickel-boron master alloy for nickel-based superalloy, characterized in that The preparation method includes the following steps: Step 1: Mix boric anhydride powder and nickel oxide powder and then press them to obtain a pre-combination reaction block; mix metallic nickel and carbon powder and then press them to obtain a thermal reduction reaction block. Step 2: Heat the pre-combination reaction block obtained in Step 1 to melting to obtain a molten product, preheat and keep warm the thermal reduction reaction block obtained in Step 1, and then mix the molten product with the thermal reduction reaction block to carry out a carbothermal reduction reaction to obtain an alloy melt; the temperature of the preheating is 1000°C to 1100°C; the process of the carbothermal reduction reaction is as follows: under the condition that the vacuum degree is lower than 5×10 -3 Pa and argon is continuously introduced, heat up to 1550°C to 1600°C, and keep warm until both the molten product and the thermal reduction reaction block are completely melted and no bubbles are generated; Step 3: Cast the alloy melt obtained in Step 2 under vacuum conditions, and cool it to obtain a nickel-boron master alloy.

2. The preparation method according to claim 1, wherein Before mixing, the boric anhydride powder, nickel oxide powder, and carbon powder in Step 1 are dried, and the pressing is all cold isostatic pressing.

3. The preparation method according to claim 1, wherein Before casting in Step 3, the alloy melt is cooled to 1200°C - 1300°C and held at this temperature.

4. 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 being 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%.

5. An apparatus applied to the preparation method according to any one of claims 1 to 4, characterized in that, It includes a pre-combination chamber (1) and a thermal reduction chamber (2) that are interconnected. 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), and an induction melting device (5) and a casting mold (8) are arranged in the thermal reduction chamber (2). A support and tilting mechanism (6) is provided on the induction melting device (5).

6. The device according to claim 5, characterized in that, A gate is arranged 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.

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

8. The device according to claim 5, characterized in that, The reaction mechanism is a reaction diversion groove (3). The reaction diversion groove (3) includes a top platform area, a middle reaction diversion area, and a bottom channel area. Heating coils (4) are installed in both the top platform area and the middle reaction diversion area.

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