Low-activation ODS steel and large-scale preparation method thereof

Abstract

The invention belongs to the technical field of novel high-temperature structural materials of energy systems, and particularly relates to low-activation ODS steel and a large-scale preparation method thereof. The low-activation ODS steel is designed in a carbon-free mode and comprises, by mass, 2.0%-12.0% of Cr, 1.0%-3.0% of W, 0.1%-0.2% of V, 0.2%-0.5% of Ti, 0.3%-0.8% of Y2O3 and the balance Fe and inevitable impurities, special raw material treatment (acoustic resonance method coating), semi-continuous large-batch ball milling (high-energy ball milling) and a special thermal machining system (hot forging and multi-pass warm forging) are used, and the low-activation ODS steel is obtained. The large-size low-activation ODS steel of hundreds of kilograms to tons can be obtained, and high-density superfine oxide dispersion particles are arranged in the steel. The large-scale preparation method of the low-activation ODS steel, provided by the invention, has relatively high production efficiency and economical efficiency, can ensure batch production and stability of the ODS steel, solves the technical bottleneck of the low-activation ODS steel in industrial production, and has relatively strong market competitiveness and application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of new high-temperature structural materials for energy systems, and more specifically relates to a low-activation ODS steel and its large-scale preparation method. Background Art

[0002] With the continuous growth of energy demand, nuclear energy technologies, especially fusion energy and fission energy, have gradually become important research directions in the future energy field. The requirements for materials in nuclear energy devices are extremely strict. Especially under the operating environments of fusion reactors and fission reactors, harsh conditions such as high temperature, strong radiation, and high pressure pose higher performance requirements for structural materials. They must have good high-temperature strength, radiation resistance, and low-activation characteristics to ensure the long-term stable operation of nuclear reactors.

[0003] Among many candidate materials, oxide dispersion strengthened (ODS) steel is widely regarded as an ideal choice in the nuclear energy field due to its excellent high-temperature strength and radiation resistance. ODS steel enhances its mechanical properties under high-temperature and radiation conditions by dispersing nanoscale oxide particles in the steel matrix. Especially in fusion reactors and fission reactors, its radiation damage resistance and high-temperature resistance are significantly better than those of conventional steel materials. If low-activation elements are used in the design of ODS steel, the obtained low-activation ODS steel is suitable for the application of fusion reactors.

[0004] However, although the existing ODS steel shows excellent performance at the laboratory scale, it still faces a series of challenges in large-scale production and practical applications. For example, traditional ODS steel preparation methods have problems such as high cost, complex processes, and uneven distribution of oxide particles, which are particularly prominent in large-scale production. The current preparation scale of ODS steel is generally a few kilograms to dozens of kilograms. How to carry out the large-scale preparation of ODS steel and obtain more than one hundred kilograms of ODS steel with stable performance in a single batch has become an important research direction in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-activation ODS steel and its large-scale preparation method to meet the requirements of fusion reactors for high-temperature structural materials. This material can also be applied to fission reactors, aeroengines, and other high-energy density systems.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention: Provide a low-activation ODS steel with a carbon-free design. By mass percentage, the components include:

[0008] Cr 2.0 - 12.0%, W 1.0 - 3.0%, V 0.1 - 0.2%, Ti 0.2 - 0.5%, and Y 2 O3 0.3 - 0.8%, the balance being Fe and inevitable impurities.

[0009] Optionally, for the low-activation ODS steel, by mass percentage, the components include: Cr 12%, W 2%, V 0.1%, Ti 0.2%, and Y 2 O 3 0.5%, the balance being Fe and inevitable impurities.

[0010] Optionally, for the low-activation ODS steel, by mass percentage, the components include: Cr 9%, W 1.5%, V 0.2%, Ti 0.2%, Y 2 O 3 0.35%, the balance being Fe and inevitable impurities.

[0011] The second technical solution of the present invention: provides a large-scale preparation method of a carbon-free designed low-activation ODS steel, the steps including:

[0012] Prepare pre-alloyed powder and Y 2 O 3 powder according to the component ratio of the above low-activation ODS steel; wherein, the pre-alloyed powder includes Cr powder, W powder, V powder, Ti powder, and Fe powder;

[0013] Use the acoustic resonance method to mix and coat the surface of the pre-alloyed powder with the Y 2 O 3 powder, and then perform high-energy ball milling to obtain ball-milled materials;

[0014] After hot isostatic pressing and sintering of the ball-milled materials, a hot isostatic pressing ingot is obtained;

[0015] After hot forging, multi-pass warm forging, and heat treatment of the hot isostatic pressing ingot, the low-activation ODS steel is obtained.

[0016] In view of the problems of limited production of low-activation ODS steel prepared by existing mechanical alloying and difficult control of uniformity in large-size preparation, the present invention provides a large-scale preparation method of low-activation ODS steel. By using special raw material treatment (acoustic resonance method coating), semi-continuous large-batch ball milling (high-energy ball milling), and special thermo-mechanical processing systems (hot forging, multi-pass warm forging), large-size low-activation ODS steel of hundreds of kilograms to tons can be obtained, which has high-density ultrafine oxide dispersion particles inside.

[0017] Further, the pre-alloyed powder is prepared by argon atomization technology, and the particle size is -200 mesh.

[0018] Further, the particle size of the Y 2 O 3 powder is 30 - 50 nm.

[0019] Further, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min.

[0020] The present invention solves the problem of the uniformity of the distribution of dispersed particles during the large-scale preparation of ODS steel by the acoustic resonance method for mixing and coating, as well as the problem of poor repeatability (the uniformity of the quality and performance of products in different batches) caused thereby.

[0021] Further, the ball-to-material ratio of the high-energy ball milling is 15 - 20:1, the ball milling medium is high-chromium steel balls, the ball milling rotation speed is 100 - 120 rpm, and the time is 30 - 50 h.

[0022] Optionally, the high-chromium steel balls are spherical and flat cylindrical, and the quantity ratio is 2:1.

[0023] Among them, the diameter of the spherical high-chromium steel balls is 20 - 30 mm; the diameter of the flat cylindrical high-chromium steel balls is 130 - 150 mm and the height is 30 mm.

[0024] The high-energy ball milling of the present invention uses spherical and flat cylindrical high-chromium steel balls, which well compensates for the insufficient energy input during the large-scale ball milling process. The larger flat cylindrical balls combined with the spherical balls can not only significantly increase the contact area between the ball milling medium and the powder during the ball milling process, making the ball milling more uniform, but also input higher energy for the powder deformation through the greater gravitational force, improving the mechanical alloying effect of the large-scale drum ball mill.

[0025] Further, the temperature of the hot isostatic pressing sintering is 1150 °C, the pressure is 140 MPa, and the time is 4 - 5 h.

[0026] Further, the hot forging is carried out at 1100 °C for heat preservation for 3 - 5 h, and the one-time forging deformation amount is 20 - 40%.

[0027] Further, the multi-pass warm forging is carried out at 600 °C for heat preservation for 2 - 10 h, the forging deformation amount is 5 - 15%, and the heat preservation - forging deformation is repeated 3 - 8 times.

[0028] The present invention performs thermo-mechanical deformation processing on the hot isostatic pressing steel ingot through hot forging and multi-pass warm forging to improve the uniformity and denseness of the alloy structure.

[0029] The present invention solves the problem of difficult thermo-mechanical processing of high-strength ODS steel well by combining hot forging and multi-pass warm forging. In particular, it can make the large-size ODS steel ingot obtain a more uniform microstructure and improve the performance.

[0030] Further, the heat treatment is to hold at 1050 °C for 5 h, then rapidly quench in water, subsequently hold at 740 - 850 °C for 5 h for tempering treatment, and finally air cool or cool in buried sand.

[0031] The low-activation ODS steel prepared by the present invention can be applied to scenarios such as the cladding of fusion reactors and the fuel cladding materials of advanced fission reactors, the structural materials of aeroengines, and the structural materials of other energy systems, which have extremely high requirements for high-temperature strength and radiation resistance.

[0032] The present invention discloses the following technical effects:

[0033] The low-activation ODS steel of the present invention uses low-activation elements as alloying components, significantly reducing the radiation damage response of the steel and reducing the activation effect of the material under long-term irradiation, which can meet the low-activation requirements of fusion reactors for structural materials.

[0034] The large-scale preparation method of the low-activation ODS steel provided by the present invention has high production efficiency and economy, can ensure the batch production and stability of ODS steel, solves the technical bottleneck of low-activation ODS steel in industrial production, and has strong market competitiveness and application prospects. Description of the Drawings

[0035] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0036] Figure 1 Schematic diagram of the large horizontal roller ball mill used in the embodiment;

[0037] Figure 2 Powder morphology diagram after acoustic resonance coating in Example 1;

[0038] Figure 3 Microstructural diagram of the low-activation ODS steel prepared in Example 1 under a transmission electron microscope. Detailed Description of the Invention

[0039] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation embodiments of the present invention.

[0040] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0042] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0043] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0044] Unless otherwise specified, the "%" involved in the specific embodiments of the present invention are all mass percentages, and the "room temperature" and "normal temperature" involved are both 20 - 30 °C.

[0045] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0046] Example 1

[0047] A method for large-scale preparation of low-activation ODS steel, the steps including:

[0048] S1. Prepare pre-alloyed powder (Cr powder, W powder, V powder, Ti powder, and Fe powder) and Y 2 O 3 powder in a proportion of Cr 12%, W 2%, V 0.1%, Ti 0.2%, Y 2 O 3 powder; with the balance being Fe;

[0049] Among them, the pre-alloyed powder is prepared by argon atomization powder technology, and the particle size is -200 mesh; Y2 O 3 The average particle size of the powder is 40 nm;

[0050] S2. Using the acoustic resonance method, the pre-alloyed powder is used to mix and coat Y 2 O 3 powder; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min; the powder morphology diagram after the treatment by the acoustic resonance method is as Figure 2 shown;

[0051] S3. The powder treated by the acoustic resonance method in step 2 is added from the feed inlet into a large horizontal drum ball mill, and the vacuum is continuously evacuated and argon is filled three times to make it in an argon atmosphere. The ball-to-material ratio is adjusted to 15:1, the rotation speed is 100 rpm, and the ball milling time is 50 h for high-energy ball milling to obtain a ball-milled material;

[0052] Among them, the volume of the large horizontal drum ball mill (as Figure 1 shown) is between 3000 - 5000 L, there is an upper feed inlet and a lower discharge outlet, it can be continuously produced, and the ball milling of 300 - 500 kg of powder can be carried out at one time; the grinding ball medium is a high-chromium steel grinding ball, and the shapes of the grinding balls are two types: spherical and flat cylindrical, and the quantity ratio is 2:1; the diameter of the spherical grinding ball is between 20 - 30 mm, and the diameter size of the flat cylindrical grinding ball is between 130 - 150 mm, and the height size is 30 mm;

[0053] S4. The ball-milled material obtained in step S3 is subjected to hot isostatic pressing sintering at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 320 kg;

[0054] S5. The cylindrical hot isostatic pressing steel ingot obtained in step S4 is kept at 1100 °C for 3 h, and then the one-time forging deformation amount is 30%; then it is kept at 600 °C for 2 h, and the forging deformation amount is 10%, and this is repeated five times; then it is kept at 1050 °C for 5 h, taken out and rapidly quenched in water at 20 °C, and then tempered at 740 °C for 5 h, and air-cooled to room temperature to obtain the low-activation ODS steel.

[0055] The low-activation ODS steel prepared in this example is measured by the Archimedes drainage method to have a relative density greater than 99.5% and no obvious cracks appear in the sample.

[0056] Figure 3 Figure

[0057] Example 2

[0058] Method for large-scale preparation of low-activation ODS steel, the steps including:

[0059] S1. Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y 2 O 3 powder in a ratio of Cr 9%, W 1.5%, V 0.2%, Ti 0.2% and Y 2 O 3 powder; the balance being Fe;

[0060] wherein, the pre-alloyed powder is prepared by argon atomization powder technology, with a particle size of -200 mesh; the average particle size of Y 2 O 3 powder is 40 nm;

[0061] S2. Adopt the acoustic resonance method to mix and coat the Y 2 O 3 powder with the pre-alloyed powder; wherein, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min;

[0062] S3. Add the powder treated by the acoustic resonance method in step 2 into a large horizontal drum ball mill from the feed inlet, continuously evacuate and fill with argon three times to make it in an argon atmosphere, adjust the ball-to-material ratio to 20:1, the rotation speed to 120 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain ball-milled material;

[0063] wherein, the volume of the large horizontal drum ball mill is between 3000 - 5000 L, there is an upper feed inlet and a lower discharge outlet, and it can be continuously produced, and the ball milling of 300 - 500 kg of powder can be carried out at one time; the grinding ball medium is high-chromium steel grinding balls, and the shapes of the grinding balls are two types: spherical and flat cylindrical, and the quantity ratio is 2:1; the diameter of the spherical grinding balls is between 20 - 30 mm, and the diameter size of the flat cylindrical grinding balls is between 130 - 150 mm, and the height size is 30 mm;

[0064] S4. Carry out hot isostatic pressing sintering on the ball-milled material obtained in step S3 at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot, with a weight of about 450 kg;

[0065] S5. Keep the cylindrical hot isostatic pressing steel ingot obtained in step S4 at 1100 °C for 3 h, and then carry out a one-time forging deformation of 40%; then keep it at 600 °C for 2 h, and the forging deformation is 10%, and repeat it five times; then keep it at 1050 °C for 3 h, take it out and quickly quench it in water at 20 °C, and then carry out tempering treatment at 850 °C for 5 h, and air-cool to room temperature to obtain low-activation ODS steel, denoted as ODS-1.

[0066] Comparative Example 1

[0067] Method for large-scale preparation of low-activation ODS steel, the steps include:

[0068] S1. Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y 2 O 3 at a ratio of 9% Cr, 1.5% W, 0.2% V, 0.2% Ti, Y 2 O 3 powder; the balance is Fe;

[0069] Among them, the pre-alloyed powder is prepared by argon atomization powder technology, and the particle size is -200 mesh; the average particle size of Y 2 O 3 powder is 40 nm;

[0070] S2. Simply mix the pre-alloyed powder raw materials and Y 2 O 3 in step 1, then add them into a horizontal planetary ball mill and continuously evacuate and fill with argon three times to make it in an argon atmosphere. Adjust the ball-to-material ratio to 10:1, the rotation speed to 140 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain ball-milled materials;

[0071] Among them, the volume of the horizontal planetary mill is between 40 - 160 L. The raw materials are added into a stainless steel ball milling tank and fixed on the horizontal planetary mill for processing and production. The ball milling of 3 - 12 kg of powder can be carried out at one time; the ball milling medium is high-chromium steel grinding balls, and the grinding ball size is between 5 mm - 15 mm;

[0072] S3. Carry out hot isostatic pressing sintering on the ball-milled materials obtained in step S2 at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 6 kg;

[0073] S4. Keep the cylindrical hot isostatic pressing steel ingot obtained in step S3 at 1150 °C for 1 h, then forge it at one time with a deformation amount of 60%; then keep it at 1050 °C for 1 h, take it out and quickly quench it in water at 20 °C, and then carry out tempering treatment at 850 °C for 1 h, and air-cool it to room temperature to obtain low-activation ODS steel, denoted as ODS-2.

[0074] Comparative Example 2

[0075] Method for large-scale preparation of low-activation ODS steel, the steps include:

[0076] S1. Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y 2 O 3Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y powder in a proportion of 0.35%, with the balance being Fe. 2 O 3 powder;

[0077] Among them, the pre-alloyed powder is prepared by argon gas atomization powder technology, with a particle size of -200 mesh; the average particle size of the Y powder is 40 nm; 2 O 3 The average particle size of the powder is 40 nm;

[0078] S2. Use the acoustic resonance method to mix and coat the Y powder with the pre-alloyed powder; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min; 2 O 3 The powder is mixed and coated; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min;

[0079] S3. Add the powder treated by the acoustic resonance method in step 2 from the feed inlet into a large horizontal drum ball mill, continuously evacuate and fill with argon three times to make it in an argon atmosphere, adjust the ball-to-material ratio to 20:1, the rotation speed to 120 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain ball-milled material;

[0080] Among them, the volume of the large horizontal drum ball mill is between 3000 - 5000 L, with an upper feed inlet and a lower discharge outlet, can be continuously produced, and can mill 300 - 500 kg of powder at a time; the grinding ball medium is high-chromium steel grinding balls, and the shapes of the grinding balls are spherical and flat cylindrical, and the quantity ratio is 2:1; the diameter of the spherical grinding balls is between 20 - 30 mm, and the diameter size of the flat cylindrical grinding balls is between 130 - 150 mm, and the height size is 30 mm;

[0081] S4. Perform hot isostatic pressing sintering on the ball-milled material obtained in step S3 at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot, with a weight of about 450 kg;

[0082] S5. Keep the cylindrical hot isostatic pressing steel ingot obtained in step S4 at 1100 °C for 3 h, then perform a one-time forging deformation of 65%; then keep it at 1050 °C for 3 h, take it out and quickly quench it in water at 20 °C, and then perform tempering treatment at 850 °C for 5 h, and air-cool to room temperature to obtain low-activation ODS steel, denoted as ODS-3.

[0083] Comparative Example 3

[0084] A method for large-scale preparation of low-activation ODS steel, the steps include:

[0085] S1. According to Cr 9%, W 1.5%, V 0.2%, Ti 0.2%, Y 2 O 3Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y powder in a proportion of 0.35%, with the balance being Fe. 2 O 3 powder;

[0086] Among them, the pre-alloyed powder is prepared by argon gas atomization powder technology, with a particle size of -200 mesh; the average particle size of Y powder is 40 nm; 2 O 3 powder is 40 nm;

[0087] S2. Use the pre-alloyed powder to mix and coat the Y powder by the acoustic resonance method; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min; 2 O 3 powder by the acoustic resonance method; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min;

[0088] S3. Add the powder treated by the acoustic resonance method in step 2 into a large horizontal drum ball mill, continuously evacuate and fill with argon three times to make it in an argon atmosphere, adjust the ball-to-material ratio to 20:1, the rotation speed to 120 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain ball-milled material;

[0089] Among them, the volume of the large horizontal drum ball mill is between 3000 - 5000 L, with an upper feed port and a lower discharge port, and can be continuously produced. The single-time ball milling can be carried out for 300 - 500 kg of powder; the grinding ball medium is high-chromium steel grinding balls, and the shapes of the grinding balls are two types: spherical and flat cylindrical, and the quantity ratio is 2:1; the diameter of the spherical grinding balls is between 20 - 30 mm, the diameter size of the flat cylindrical grinding balls is between 130 - 150 mm, and the height size is 30 mm;

[0090] S4. Carry out hot isostatic pressing sintering on the ball-milled material obtained in step S3 at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 450 kg;

[0091] S5. Keep the cylindrical hot isostatic pressing steel ingot obtained in step S4 at 600 °C for 2 h, the forging deformation amount is about 10%, and repeat it six times, with a total deformation amount of about 65%; then keep it at 1050 °C for 3 h, take it out and quickly quench it in water at 20 °C, and then carry out tempering treatment at 850 °C for 5 h and air-cool it to room temperature to obtain low-activation ODS steel, denoted as ODS-4.

[0092] Comparative Example 4

[0093] A method for large-scale preparation of low-activation ODS steel, the steps include:

[0094] S1. According to Cr 9%, W 1.5%, V 0.2%, Ti 0.2%, Y 2 O 3Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y powder in a proportion of 0.35%, with the balance being Fe 2 O 3 powder;

[0095] Among them, the pre-alloyed powder is prepared by argon gas atomization powder technology, with a particle size of -200 mesh; the average particle size of Y powder is 40 nm; 2 O 3 The average particle size of the powder is 40 nm;

[0096] S2. After mixing the pre-alloyed powder and Y powder evenly, add them into a large horizontal roller ball mill from the feeding port, continuously evacuate and fill with argon three times to make it in an argon atmosphere, adjust the ball-to-material ratio to 20:1, the rotation speed to 120 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain ball-milled materials; 2 O 3 Among them, the volume of the large horizontal roller ball mill is between 3000 - 5000 L, with an upper feeding port and a lower discharging port, and can be continuously produced. Each time, 300 - 500 kg of powder can be ball milled; the grinding ball medium is high-chromium steel grinding balls, and the shapes of the grinding balls are spherical and flat cylindrical, with a quantity ratio of 2:1; the diameter of the spherical grinding balls is between 20 - 30 mm, the diameter size of the flat cylindrical grinding balls is between 130 - 150 mm, and the height size is 30 mm;

[0097] Among them, the volume of the large horizontal roller ball mill is between 3000 - 5000 L, with an upper feeding port and a lower discharging port, and can be continuously produced. Each time, 300 - 500 kg of powder can be ball milled; the grinding ball medium is high-chromium steel grinding balls, and the shapes of the grinding balls are spherical and flat cylindrical, with a quantity ratio of 2:1; the diameter of the spherical grinding balls is between 20 - 30 mm, the diameter size of the flat cylindrical grinding balls is between 130 - 150 mm, and the height size is 30 mm;

[0098] S3. Perform hot isostatic pressing sintering on the ball-milled materials obtained in step S2 at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 450 kg;

[0099] S4. Keep the cylindrical hot isostatic pressing steel ingot obtained in step S3 at 1100 °C for 3 h, and then perform a one-time forging deformation of 40%; then keep it at 600 °C for 2 h, and the forging deformation is 10%, and repeat it five times; the final total deformation is 65%; then keep it at 1050 °C for 3 h, take it out and quickly quench it in water at 20 °C, and then perform tempering treatment at 850 °C for 5 h, and air-cool it to room temperature to obtain low-activation ODS steel, denoted as ODS-5.

[0100] Comparative Example 5

[0101] A method for large-scale preparation of low-activation ODS steel, the steps include:

[0102] S1. Prepare raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y powder in a proportion of Cr 9%, W 1.5%, V 0.2%, Ti 0.2%, Y 2 O 3 0.35%, with the balance being Fe, and Y 2 O3 Powder;

[0103] Among them, the pre-alloyed powder is prepared by argon atomization powder technology, and the particle size is -200 mesh; Y 2 O 3 The average particle size of the powder is 40 nm;

[0104] S2. Using the acoustic resonance method, the pre-alloyed powder is used to mix and coat the Y 2 O 3 powder; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min;

[0105] S3. The powder treated by the acoustic resonance method in step 2 is added from the feed port into a large horizontal drum ball mill, and the vacuum is evacuated and argon is filled continuously three times to make it in an argon atmosphere. Adjust the ball-to-material ratio to 20:1, the rotation speed to 120 rpm, and the ball milling time to 30 h for high-energy ball milling to obtain the ball-milled material;

[0106] Among them, the volume of the large horizontal drum ball mill is between 3000 - 5000 L, there is an upper feed port and a lower discharge port, and it can be continuously produced. The ball milling of 300 - 500 kg of powder can be carried out at one time; the grinding ball medium is a high-chromium steel grinding ball, and the shape of the grinding ball is a flat cylindrical shape; the diameter size of the flat cylindrical grinding ball is between 130 - 150 mm, and the height size is 30 mm;

[0107] S4. The ball-milled material obtained in step S3 is subjected to hot isostatic pressing sintering at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 450 kg;

[0108] S5. The cylindrical hot isostatic pressing steel ingot obtained in step S4 is kept at 1100 °C for 3 h, and then the one-time forging deformation amount is 40%; then it is kept at 600 °C for 2 h, and the forging deformation amount is 10%, and this is repeated five times; the final total deformation amount is 65%; then it is kept at 1050 °C for 3 h, taken out and quickly quenched in water at 20 °C, and then tempered at 850 °C for 5 h, and air-cooled to room temperature to obtain the low-activation ODS steel, denoted as ODS-6.

[0109] Comparative Example 6

[0110] A method for large-scale preparation of low-activation ODS steel, the steps include:

[0111] S1. Prepare the raw material pre-alloyed powder (Cr powder, W powder, V powder, Ti powder and Fe powder) and Y 2 O 3 at a ratio of 0.35%, with the balance being Fe, 2 O 3Powder;

[0112] Among them, the pre-alloyed powder is prepared by argon atomization powder technology, and the particle size is -200 mesh; Y 2 O 3 The average particle size of the powder is 40 nm;

[0113] S2. Using the acoustic resonance method, the pre-alloyed powder is used to mix and coat the Y 2 O 3 powder; among them, the frequency of the acoustic resonance method is 100 Hz and the time is 20 min;

[0114] S3. The powder treated by the acoustic resonance method in step 2 is added from the feed port into a large horizontal drum ball mill, and the vacuum is evacuated and argon is filled three times continuously to make it in an argon atmosphere. The ball-to-material ratio is adjusted to 20:1, the rotation speed is 120 rpm, and the ball milling time is 30 h for high-energy ball milling to obtain ball-milled material;

[0115] Among them, the volume of the large horizontal drum ball mill is between 3000 - 5000 L, there is an upper feed port and a lower discharge port, it can be continuously produced, and the ball milling of 300 - 500 kg of powder can be carried out at one time; the grinding ball medium is high-chromium steel grinding balls, and the shape of the grinding balls is spherical; the diameter of the spherical grinding balls is between 20 - 30 mm;

[0116] S4. The ball-milled material obtained in step S3 is subjected to hot isostatic pressing sintering at 1150 °C and 140 MPa for 4 h to obtain a cylindrical hot isostatic pressing steel ingot with a weight of about 450 kg;

[0117] S5. The cylindrical hot isostatic pressing steel ingot obtained in step S4 is kept at 1100 °C for 3 h, and then the one-time forging deformation amount is 40%; then it is kept at 600 °C for 2 h, and the forging deformation amount is 10%, and this is repeated five times; the final total deformation amount is 65%; then it is kept at 1050 °C for 3 h, taken out and quickly quenched in water at 20 °C, and then tempered at 850 °C for 5 h, and air-cooled to room temperature to obtain low-activation ODS steel, denoted as ODS-7.

[0118] Test example

[0119] The low-activation ODS steel prepared in Example 2 and Comparative Examples 1 - 6 was subjected to a room temperature tensile test, and the results are shown in Table 1.

[0120] Room temperature tensile test method: According to GB / T228.1 - 2010, the sample is processed into an M6 / 3 circular proportional rod-shaped tensile specimen with a gauge length of 15 mm and a gauge section diameter of 3 mm, and three tensile rods are tested and the average value is taken.

[0121] Table 1

[0122] Sample Tensile strength at room temperature (MPa) Elongation after fracture (%) ODS-1 1140 18.9 ODS-2 1120 19.2 ODS-3 1050 17.3 ODS-4 1020 19.3 ODS-5 970 19.1 ODS-6 890 17.5 ODS-7 1010 18.2

[0123] As can be seen from the data in Table 1, by comparing the performance data of ODS-1 and ODS-2, it can be known that the tensile performance of (ODS-1) after batch amplification can be maintained at the level of the original small-batch preparation (ODS-2). Compared with ODS-1, ODS-3 achieves a deformation of 65% through one hot forging, ODS-4 achieves a deformation of 65% through six warm forging, ODS-5 reduces the acoustic resonance cladding treatment, ODS-6 uses a single flat cylindrical grinding ball during ball milling, and ODS-7 uses a single spherical grinding ball during ball milling. From the data, it can be seen that the special thermo-mechanical processing system (hot forging + multiple temperature forging + heat treatment) can increase the room temperature tensile strength by about 100 MPa compared with ordinary hot forging and multiple warm forging. The acoustic resonance cladding can increase the room temperature tensile strength by 120 MPa. The combination of flat cylindrical grinding balls and spherical grinding balls for the ball milling medium can increase the room temperature tensile performance by 250 MPa and 130 MPa respectively compared with a single flat cylindrical grinding ball and a single spherical grinding ball. These preparation measures can greatly ensure the performance superiority and stability of the low-activation ODS steel in mass production.

[0124] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts between the embodiments, reference can be made to each other.

[0125] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-activated ODS steel with a carbon-free design, characterized in that: In terms of mass percentage, the components include: Cr 2.0-12.0%, W 1.0-3.0%, V 0.1-0.2%, Ti 0.2-0.5% and Y2O3 0.3-0.8%, and the balance is Fe and inevitable impurities.

2. The low-activated ODS steel according to claim 1, characterized in that: The low-activation ODS steel comprises, by mass percentage, 12% Cr, 2% W, 0.1% V, 0.2% Ti and 0.5% Y2O3, with the remainder being Fe and unavoidable impurities.

3. The low-activated ODS steel according to claim 1, characterized in that: The low-activation ODS steel comprises, by mass percentage, 9% Cr, 1.5% W, 0.2% V, 0.2% Ti and 0.35% Y2O3, with the remainder being Fe and unavoidable impurities.

4. A large-scale preparation method of low-activated ODS steel with carbon-free design, characterized in that the steps include: Pre-alloyed powder and Y2O3 powder are prepared according to the composition ratio of the low-activated ODS steel according to any one of claims 1 to 3; wherein the pre-alloyed powder comprises Cr powder, W powder, V powder, Ti powder and Fe powder; The Y2O3 powder is used to mix and coat the surface of the pre-alloyed powder by using an acoustic resonance method, and then high-energy ball milling is performed to obtain a ball-milled material; Hot isostatic pressing and sintering the ball-milled material to obtain a hot isostatic pressed steel ingot; The low-activation ODS steel is obtained by subjecting the hot isostatically pressed steel ingot to hot forging, multi-pass warm forging and heat treatment.

5. The preparation method according to claim 4, characterized in that: The pre-alloyed powder is prepared by argon atomization technology, and has a particle size of -200 mesh; and / or, the particle size of the Y2O3 powder is 30-50nm.

6. The preparation method according to claim 4, characterized in that: The frequency of the acoustic resonance method is 100 Hz, and the time is 20 minutes; and / or, the ball-to-material ratio of the high-energy ball mill is 15-20:1, the grinding ball medium is high-chromium steel grinding balls, the ball milling speed is 100-120 rpm, and the time is 30-50 hours.

7. The preparation method according to claim 6, characterized in that: The high chromium steel grinding balls are spherical and oblate cylindrical, with a quantity ratio of 2:

1.

8. The preparation method according to claim 4, characterized in that: The hot isostatic pressing sintering is carried out at a temperature of 1150° C., a pressure of 140 MPa and a time of 4-5 hours.

9. The preparation method according to claim 4, characterized in that: The hot forging is performed at 1100°C for 3-5 hours, with a one-time forging deformation of 20-40%; and / or the multi-pass warm forging is performed at 600°C for 2-10 hours, with a forging deformation of 5-15%, and the warm forging and deformation are repeated 3-8 times.

10. The preparation method according to claim 4, characterized in that: The heat treatment is to keep the temperature at 1050° C. for 5 hours, then quickly quench in water, then keep the temperature at 740-850° C. for 5 hours for tempering, and finally cool in air or bury in sand.

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