Preparation method of nuclear power main pump flywheel

Abstract

The invention particularly relates to a nuclear power main pump flywheel preparation method which comprises the steps that the size of a nuclear power main pump flywheel is determined according to the performance requirement of a nuclear power main pump, the use amount of a raw material composed of a depleted uranium material is determined according to the size of the nuclear power main pump flywheel, and the depleted uranium material is a uranium-molybdenum alloy composed of 99.5 wt% of uranium element and 0.5 wt% of molybdenum element; weighing the raw materials according to the determined raw material dosage and putting into an induction melting furnace; preheating an induction melting furnace, and heating until the raw materials in the induction melting furnace are dissolved into a liquid state to obtain a liquid raw material; preparing the liquid raw material into a nuclear power main pump flywheel blank and cooling; the nuclear power main pump flywheel blank is put into a heat treatment furnace for heat treatment, uranium in the nuclear power main pump flywheel blank is subjected to a phase change reaction, and then the nuclear power main pump flywheel blank is cooled to the room temperature; and the nuclear power main pump flywheel blank is finely machined to the size of the nuclear power main pump flywheel, and the nuclear power main pump flywheel is manufactured. According to the invention, the mechanical properties, especially the density and the ductility, of the nuclear power main pump flywheel are improved.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing flywheels for depleted uranium nuclear power main pumps, and in particular to a method for preparing a flywheel for a nuclear power main pump. Background Art

[0002] Nuclear power generation is being widely used as a new type of clean energy. The flywheel of the nuclear power main pump is one of the important equipment in the nuclear power plant. It is usually used to provide additional rotational inertia and stability to balance the power changes of the main pump system of the nuclear power plant to ensure the safe and reliable operation of the nuclear power plant. The nuclear power main pump is the equipment responsible for circulating the coolant in the nuclear power plant. It sends the high-temperature and high-pressure coolant into the nuclear reactor and recycles the low-temperature and low-pressure coolant that flows out. Since the power change of the nuclear reactor may be relatively fast, the workload of the nuclear power main pump will also change. At this time, the nuclear power main pump flywheel is needed to balance the power change. The nuclear power main pump flywheel can store and release energy through inertia. When the nuclear power plant main pump system needs additional power, the nuclear power main pump flywheel will release the storage capacity and provide additional rotational power, so as to meet the coolant flow requirements of the nuclear reactor at different powers. Conversely, when the nuclear power plant main pump system is overloaded or fails, the nuclear power main pump flywheel can absorb excess energy, reduce the load on the nuclear power main pump, and protect the safety of the nuclear power main pump and nuclear reactor. The two factors that determine the energy storage of the nuclear power main pump flywheel are the nuclear power main pump flywheel speed and the nuclear power main pump flywheel's own weight. The higher the nuclear power main pump flywheel speed and the nuclear power main pump flywheel's own weight, the higher the energy stored in the nuclear power main pump flywheel. However, increasing the nuclear power main pump flywheel speed will make the nuclear power main pump difficult to control and the safety performance cannot be guaranteed. Therefore, the method of increasing the mass of the nuclear power main pump flywheel is usually used, that is, selecting high-density and high-strength materials.

[0003] The high-density material used in the flywheel of the nuclear power main pump is mainly tungsten alloy. Tungsten alloy has high density and hardness, but it is difficult to process and cannot be prepared into an integral nuclear power main pump flywheel. It is usually assembled into the steel shell of the nuclear power main pump flywheel in the form of fan-shaped blocks or plugs to increase the rotational inertia of the nuclear power main pump flywheel. The research and development of depleted uranium nuclear power main pump flywheel has also been carried out in China. The depleted uranium material used is uranium-2% molybdenum alloy, and its preparation process is alloy smelting, centrifugal casting, high-temperature long-term annealing and machining. The depleted uranium nuclear power main pump flywheel basically meets the application requirements, but the density and elongation are low, which limits the application of depleted uranium nuclear power main pump flywheel to a certain extent. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a flywheel for a nuclear power main pump, so that the mechanical properties, especially the density and elongation, of the flywheel for the nuclear power main pump are improved.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a nuclear power main pump flywheel comprises the following steps:

[0007] Step 1, according to the performance requirements of the nuclear power main pump, determine the size of the nuclear power main pump flywheel; according to the size of the nuclear power main pump flywheel, determine the amount of raw materials composed of depleted uranium materials; the depleted uranium material is a uranium-molybdenum alloy composed of 99.5wt% uranium element and 0.5wt% molybdenum element;

[0008] Step 2, weighing the raw materials according to the determined raw material dosage and putting them into the induction melting furnace;

[0009] Step 3, after preheating the induction melting furnace, heating until the raw materials in the induction melting furnace are dissolved into liquid, to obtain liquid raw materials;

[0010] Step 4, making the liquid raw material into a nuclear power main pump flywheel blank and cooling it;

[0011] Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment, so that the uranium in the nuclear power main pump flywheel blank undergoes a phase change reaction, and then cooling to room temperature;

[0012] Step 6: Finely process the nuclear power main pump flywheel blank to the size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

[0013] As one of the feasible ways, in step 1, the size of the flywheel of the nuclear power main pump is determined according to the power and operating speed requirements of the flywheel of the nuclear power main pump.

[0014] As one achievable manner, in step 1, the uranium-molybdenum alloy is composed of 99.5wt% uranium ingots and 0.5wt% molybdenum particles.

[0015] As one of the feasible ways, in step 3, the induction melting furnace is heated to 600°C and kept warm for 30 minutes to complete the preheating of the induction melting furnace; after the induction melting furnace is preheated, it is heated to (1400-1500)°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials.

[0016] As one of the feasible ways, in step 4, the liquid raw material is centrifugally cast in a mold to form a nuclear power main pump flywheel blank and then cooled.

[0017] As another feasible method, in step 4, the liquid raw material is poured into an ingot in a mold, and then the ingot is forged at high temperature into a nuclear power main pump flywheel blank and cooled.

[0018] As another feasible method, in step 4, the liquid raw material is poured into an ingot in a mold, the ingot is heated to 1000° C., and then kept warm for 6 hours, forged into a nuclear power main pump flywheel blank and cooled.

[0019] As one of the achievable methods, step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment to cause the uranium in the nuclear power main pump flywheel blank to undergo a phase change reaction, and then cooling to room temperature, comprises the following steps:

[0020] The flywheel blank of the nuclear power main pump is placed in a heat treatment furnace, filled with protective gas, heated to (800-850)°C within 60 minutes, and then cooled and annealed to (500-600)°C at 10°C / min. After keeping warm for 24 hours, it is cooled to room temperature with the heat treatment furnace.

[0021] As one of the feasible ways, in step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction:

[0022] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure;

[0023] When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β;

[0024] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α P The phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure;

[0025] When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure;

[0026] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases;

[0027] When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

[0028] As one achievable manner, in step 5, the protective gas is argon.

[0029] Beneficial technical effects of the present invention:

[0030] The preparation method of the nuclear power main pump flywheel of the present invention uses a quasi-eutectic uranium-0.5wt% molybdenum alloy as a raw material, improves the fluidity of the solution, and improves the performance of the uranium-0.5wt% molybdenum alloy nuclear power main pump flywheel by reducing the heat treatment temperature; at the same time, the phase change reaction and temperature range of the uranium-0.5% molybdenum alloy nuclear power main pump flywheel blank during the heat treatment process are clarified, so that the performance of the manufactured nuclear power main pump flywheel is more stable; the density and elongation of the uranium-0.5% molybdenum alloy nuclear power main pump flywheel are better than those of the uranium-2% molybdenum alloy nuclear power main pump flywheel. DETAILED DESCRIPTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0032] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] The present invention provides a method for preparing a nuclear power main pump flywheel, comprising the following steps:

[0034] Step 1, according to the performance requirements of the nuclear power main pump, determine the size of the nuclear power main pump flywheel; according to the size of the nuclear power main pump flywheel, determine the amount of raw materials composed of depleted uranium materials; the depleted uranium material is a uranium-molybdenum alloy composed of 99.5wt% uranium element and 0.5wt% molybdenum element;

[0035] Step 2, weighing the raw materials according to the determined raw material dosage and putting them into the induction melting furnace;

[0036] Step 3, after preheating the induction melting furnace, heating until the raw materials in the induction melting furnace are dissolved into liquid, to obtain liquid raw materials;

[0037] Step 4, making the liquid raw material into a nuclear power main pump flywheel blank and cooling it;

[0038] Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment, so that the uranium in the nuclear power main pump flywheel blank undergoes a phase change reaction, and then cooling to room temperature;

[0039] Step 6: Finely process the nuclear power main pump flywheel blank to the shape and size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

[0040] In the present invention, as one of the achievable methods, in step 1, the size of the flywheel of the nuclear power main pump is determined according to the power and operating speed requirements of the flywheel of the nuclear power main pump.

[0041] In the present invention, as one achievable method, in step 1, the uranium-molybdenum alloy is composed of 99.5wt% uranium ingots and 0.5wt% molybdenum particles.

[0042] In the present invention, as one of the achievable methods, in step 3, the induction melting furnace is heated to 600°C and kept warm for 30 minutes to complete the preheating of the induction melting furnace; after the induction melting furnace is preheated, it is heated to (1400-1500)°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials.

[0043] In the present invention, as one of the achievable methods, in step 4, the liquid raw material is centrifugally cast in a mold to form a nuclear power main pump flywheel blank and then cooled.

[0044] In the present invention, as another achievable method, in step 4, the liquid raw material is poured into an ingot in a mold, and then the ingot is forged at high temperature into a nuclear power main pump flywheel blank and cooled.

[0045] In the present invention, as another achievable method, in step 4, the liquid raw material is poured into an ingot in a mold, the ingot is heated to 1000° C., and then kept warm for 6 hours, forged into a nuclear power main pump flywheel blank and cooled.

[0046] In the present invention, as one of the achievable methods, step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment, causing the uranium in the nuclear power main pump flywheel blank to undergo a phase change reaction, and then cooling to room temperature, comprises the following steps:

[0047] The flywheel blank of the nuclear power main pump is placed in a heat treatment furnace, filled with protective gas, heated to (800-850)°C within 60 minutes, and then cooled and annealed to (500-600)°C at 10°C / min. After keeping warm for 24 hours, it is cooled to room temperature with the heat treatment furnace.

[0048] In the present invention, as one of the achievable methods, in step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction:

[0049] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure;

[0050] When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β;

[0051] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α P The phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure;

[0052] When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure;

[0053] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases;

[0054] When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

[0055] In the present invention, as one achievable method, in step 5, the protective gas is argon.

[0056] The technical solution of the present invention is clearly and completely described below in conjunction with specific embodiments.

[0057] Example 1

[0058] This embodiment provides a method for preparing a nuclear power main pump flywheel, comprising the following steps:

[0059] Step 1, according to the power and running speed requirements of the flywheel of the nuclear power main pump, determine the size of the flywheel of the nuclear power main pump; according to the size of the flywheel of the nuclear power main pump, determine the amount of raw materials consisting of 99.5wt% uranium ingots and 0.5wt% molybdenum particles;

[0060] Step 2, weighing uranium ingots and metal molybdenum particles according to the determined raw material dosage, and placing them into an induction melting furnace;

[0061] Step 3, preheating the induction melting furnace to 600°C, keeping the temperature for 30 minutes, and then heating to 1400°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials;

[0062] Step 4, centrifugally casting the liquid raw material in a mold to form a nuclear power main pump flywheel blank and cooling the blank;

[0063] Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace, filling it with argon as a protective gas, heating it to 800°C within 60 minutes, then cooling and annealing it to 500°C at a rate of 10°C / min, and cooling it to room temperature with the heat treatment furnace after keeping it warm for 24 hours;

[0064] Step 6: Finely process the nuclear power main pump flywheel blank to the shape and size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

[0065] In this embodiment, in step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction:

[0066] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure;

[0067] When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β;

[0068] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α P The phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure;

[0069] When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure;

[0070] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases;

[0071] When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

[0072] The density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material in this embodiment is 98.0% of the theoretical density, while the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is 98.7% of the theoretical density. It can be seen that the density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0073] In this embodiment, the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is 14%, while the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is (5-10)%. It can be seen that the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0074] Example 2

[0075] This embodiment provides a method for preparing a nuclear power main pump flywheel, comprising the following steps:

[0076] Step 1, according to the power and running speed requirements of the flywheel of the nuclear power main pump, determine the size of the flywheel of the nuclear power main pump; according to the size of the flywheel of the nuclear power main pump, determine the amount of raw materials consisting of 99.5wt% uranium ingots and 0.5wt% molybdenum particles;

[0077] Step 2, weighing uranium ingots and molybdenum particles according to the determined raw material dosage, and placing them into an induction melting furnace;

[0078] Step 3, preheating the induction melting furnace to 600°C, keeping the temperature for 30 minutes, and then heating to 1500°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials;

[0079] Step 4, centrifugally casting the liquid raw material in a mold to form a nuclear power main pump flywheel blank and cooling the blank;

[0080] Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace, filling it with argon as a protective gas, heating it to 850°C within 60 minutes, then cooling and annealing it to 600°C at a rate of 10°C / min, and cooling it to room temperature with the heat treatment furnace after keeping it warm for 24 hours;

[0081] Step 6: Finely process the nuclear power main pump flywheel blank to the size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

[0082] In this embodiment, in step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction:

[0083] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure;

[0084] When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β;

[0085] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α PThe phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure;

[0086] When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure;

[0087] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases;

[0088] When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

[0089] The density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material in this embodiment is 97.8%, while the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is 98.7% of the theoretical density. It can be seen that the density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0090] In this embodiment, the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is 14%, while the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is (5-10)%. It can be seen that the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0091] Example 3

[0092] This embodiment provides a method for preparing a nuclear power main pump flywheel, comprising the following steps:

[0093] Step 1, according to the power and running speed requirements of the flywheel of the nuclear power main pump, determine the size of the flywheel of the nuclear power main pump; according to the size of the flywheel of the nuclear power main pump, determine the amount of raw materials consisting of 99.5wt% uranium ingots and 0.5wt% molybdenum particles;

[0094] Step 2, weighing uranium ingots and molybdenum particles according to the determined raw material dosage, and placing them into an induction melting furnace;

[0095] Step 3, preheating the induction melting furnace to 600°C, keeping the temperature for 30 minutes, and then heating to 1450°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials;

[0096] Step 4, pouring the liquid raw material into an ingot in a mold, heating the ingot to 1000° C., then keeping the ingot at this temperature for 6 hours, forging it into a nuclear power main pump flywheel blank, and cooling it;

[0097] Step 5, placing the flywheel blank of the nuclear power main pump into a heat treatment furnace, filling it with argon as a protective gas, heating it to 820°C within 60 minutes, then cooling and annealing it to 550°C at a rate of 10°C / min, keeping it warm for 24 hours, and then cooling it to room temperature along with the heat treatment furnace;

[0098] Step 6: Finely process the nuclear power main pump flywheel blank to the size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

[0099] In this embodiment, in step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction:

[0100] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure;

[0101] When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β;

[0102] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α P The phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure;

[0103] When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure;

[0104] When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases;

[0105] When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

[0106] The density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material in this embodiment is 98.2%, while the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is 98.7% of the theoretical density. It can be seen that the density of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the density of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0107] In this embodiment, the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is 15%, while the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material is (5-10)%. It can be seen that the elongation of the nuclear power main pump flywheel made of uranium-0.5% molybdenum alloy as raw material is higher than the elongation of the nuclear power main pump flywheel made of uranium-2% molybdenum alloy as raw material.

[0108] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a nuclear power main pump flywheel, characterized in that: The steps include: Step 1, according to the performance requirements of the nuclear power main pump, determine the size of the nuclear power main pump flywheel; according to the size of the nuclear power main pump flywheel, determine the amount of raw materials composed of depleted uranium materials; the depleted uranium material is a uranium-molybdenum alloy composed of 99.5wt% uranium element and 0.5wt% molybdenum element; Step 2, weighing the raw materials according to the determined raw material dosage and putting them into the induction melting furnace; Step 3, after preheating the induction melting furnace, heating until the raw materials in the induction melting furnace are dissolved into liquid, to obtain liquid raw materials; Step 4, making the liquid raw material into a nuclear power main pump flywheel blank and cooling it; Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment, so that the uranium in the nuclear power main pump flywheel blank undergoes a phase change reaction, and then cooling to room temperature; Step 6: Finely process the nuclear power main pump flywheel blank to the size of the nuclear power main pump flywheel to make the nuclear power main pump flywheel.

2. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: In step 1, the uranium-molybdenum alloy is composed of 99.5wt% uranium ingot and 0.5wt% molybdenum particles.

3. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: Step 5, placing the nuclear power main pump flywheel blank into a heat treatment furnace for heat treatment to cause the uranium in the nuclear power main pump flywheel blank to undergo a phase change reaction, and then cooling to room temperature, comprises the following steps: The flywheel blank of the nuclear power main pump is placed in a heat treatment furnace, filled with protective gas, heated to (800-850)°C within 60 minutes, and then cooled and annealed to (500-600)°C at 10°C / min. After keeping warm for 24 hours, it is cooled to room temperature with the heat treatment furnace.

4. The method for preparing a nuclear power main pump flywheel according to claim 3, characterized in that: In step 5, the uranium in the flywheel billet of the nuclear power main pump undergoes the following phase change reaction: When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 760℃ and greater than or equal to 700℃, the uranium β phase nucleates and grows along the γ parent phase grain boundary, presenting an equiaxed crystalline structure; When the flywheel blank of the nuclear power main pump is cooled and annealed to less than 700℃ and greater than or equal to 660℃, the uranium is in the β single phase region, no phase reaction occurs, and the structure is equiaxed β; When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 660℃ and greater than 615℃, the β phase of uranium first eutectoids the α P Phase, α P The phase nucleates along the grain boundary of the β-phase and grows inside the grain, presenting an equiaxed crystalline structure; When the flywheel blank of the nuclear power main pump is cooled and annealed to 615℃, the residual β phase of uranium eutectoid decomposes to form eutectoid structure; When the flywheel blank of the nuclear power main pump is cooled and annealed to a temperature less than 615℃ and greater than 583℃, uranium is desolvated and γ II Phase, γ II The phases grow dependently on the original phases; When the flywheel blank of the nuclear power main pump is cooled and annealed to 583℃, the uranium γ phase eutectoid decomposes to form long linear γ o Eutectoid structure, at this time, the structure of the nuclear power main pump flywheel blank is α P +(α+γ o ) E .

5. The method for preparing a nuclear power main pump flywheel according to claim 3, characterized in that: In step 5, the protective gas is argon.

6. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: In step 3, the induction melting furnace is heated to 600°C and kept warm for 30 minutes to complete the preheating of the induction melting furnace; after the induction melting furnace is preheated, it is heated to (1400-1500)°C to dissolve the raw materials in the induction melting furnace into liquid to obtain liquid raw materials.

7. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: In step 4, the liquid raw material is centrifugally cast in a mold to form a nuclear power main pump flywheel blank and cooled.

8. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: In step 4, the liquid raw material is poured into an ingot in a mold, and then the ingot is forged at high temperature into a nuclear power main pump flywheel blank and cooled.

9. The method for preparing a nuclear power main pump flywheel according to claim 8, characterized in that: In step 4, the liquid raw material is poured into an ingot in a mold, the ingot is heated to 1000° C., and then kept warm for 6 hours before being forged into a nuclear power main pump flywheel blank and cooled.

10. The method for preparing a nuclear power main pump flywheel according to claim 1, characterized in that: In step 1, the size of the flywheel of the nuclear power main pump is determined according to the power and operating speed requirements of the flywheel of the nuclear power main pump.