Cobalt-based alloy, alloy powder and manufacturing method thereof
By adjusting the composition and process of cobalt-based alloys, reducing the carbon content, and using an atomization process to prepare alloy powder, the problems of uneven density and decarburization in cobalt-based alloy powder parts were solved, thereby improving the mechanical and high-temperature properties of the parts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-21
AI Technical Summary
Existing cobalt-based alloy powders have high carbon and oxygen content, resulting in uneven density distribution, severe decarburization, and poor mechanical properties, which affect the quality and strength of the parts.
By adjusting the composition of the cobalt-based alloy, reducing the carbon content, and using heating and atomization processes under an inert atmosphere, uniformly sized alloy powder is prepared to avoid the formation of brittle carbides. Components are then manufactured using a pressing and sintering method.
It achieves a uniform density distribution in the parts, reduces decarburization, improves the mechanical properties and strength of the parts, and enhances the wear resistance and oxidation resistance at high temperatures.
Smart Images
Figure CN121896510A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of cobalt-based alloys, and in particular to a cobalt-based alloy, alloy powder, and a method for manufacturing the same. Background Technology
[0002] The existing cobalt-based alloy powder has a high carbon and oxygen content, with the oxygen content reaching 2000-3000 ppm, and poor fluidity. Therefore, when using cobalt-based alloy powder to prepare parts by pressing and sintering, the parts have uneven powder filling, resulting in uneven density distribution and affecting the quality of the parts.
[0003] In addition, the parts suffer from severe decarburization during the sintering process, resulting in poor mechanical properties and reduced strength. Summary of the Invention
[0004] To address the severe decarburization problem in existing cobalt-based alloys, this application provides a cobalt-based alloy, alloy powder, and a method for manufacturing the same.
[0005] In one aspect of this disclosure, a cobalt-based alloy is proposed, comprising, by weight percentage (wt%): Cr 1-40%, Mo 1-40%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0006] By adopting the above technical solutions, the carbon content of cobalt-based alloys is reduced, avoiding the formation of a large amount of brittle carbides, thus making the material less prone to cracking under impact loads. Furthermore, the low carbon content and slight decarburization of cobalt-based alloys prevent a deterioration in the mechanical properties and strength of cobalt-based alloy powder products.
[0007] Preferably, the cobalt-based alloy comprises, by weight percentage (wt%): Cr 2-15%, Mo 12-35%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0008] By adopting the above technical solutions, the carbon content of cobalt-based alloys is reduced, avoiding the formation of a large amount of brittle carbides, thus making the material less prone to cracking under impact loads. Furthermore, the low carbon content and slight decarburization of cobalt-based alloys prevent a deterioration in the mechanical properties and strength of cobalt-based alloy powder products.
[0009] Preferably, by weight percentage (wt%), it comprises: Cr 5-10%, Mo 25-30%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0010] By adopting the above technical solutions, the carbon content of cobalt-based alloys is reduced, avoiding the formation of a large amount of brittle carbides, thus making the material less prone to cracking under impact loads. Furthermore, the low carbon content and slight decarburization of cobalt-based alloys prevent a deterioration in the mechanical properties and strength of cobalt-based alloy powder products.
[0011] In another aspect of this disclosure, an alloy powder is provided, wherein the alloy powder material is a cobalt-based alloy of any of the foregoing.
[0012] By adopting the above technical solution, the alloy powder obtained is used to prepare parts by pressing and sintering. During this process, the parts are only slightly decarburized, and their mechanical properties and strength are not reduced.
[0013] In another aspect of this disclosure, a method for manufacturing alloy powder is provided, comprising: Cr, Mo, Si, C and Co are mixed and heated under an inert atmosphere until melted, and stirred evenly to form an alloy liquid; The molten alloy is atomized into alloy powder.
[0014] By adopting the above technical solution, the alloy powder obtained is used to prepare parts by pressing and sintering. During this process, the parts are only slightly decarburized, and their mechanical properties and strength are not reduced.
[0015] Preferably, the temperature at which the material is heated to melt is 1400-1750°C.
[0016] By adopting the above technical solution, the cobalt-based alloy raw materials are ensured to be fully melted.
[0017] Preferably, the atomization method includes water atomization and air atomization.
[0018] By adopting the above technical solutions, alloy powders can be prepared using different atomization methods according to different target requirements.
[0019] Preferably, when the atomization method is water atomization, the method for manufacturing the alloy powder further includes: The alloy powder is collected and dehydrated, then dried, sieved, and batched.
[0020] By adopting the above technical solution, alloy powder with uniform particle size and excellent quality can be obtained.
[0021] Preferably, the drying is low-temperature drying.
[0022] By adopting the above technical solution, oxidation of alloy powder can be prevented.
[0023] Preferably, the water flow pressure during water atomization is 10 to 35 MPa.
[0024] By adopting the above technical solution, it is ensured that the high-pressure water flow can violently impact the molten metal flow, forming countless tiny droplet alloys. After the droplet alloys cool, they become alloy powder.
[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. The cobalt-based alloy of this application reduces the carbon content and avoids the formation of a large number of brittle carbides, making the material less prone to cracking when subjected to impact loads.
[0026] 2. Cobalt-based alloys have low carbon content and slight decarburization, which will not cause a deterioration in the mechanical properties and strength of cobalt-based alloy powder products.
[0027] 3. The cobalt-based alloy is strengthened by solid solution with a very high molybdenum content, and supplemented with intermetallic compounds Cr and Si. Solid solution strengthening and intermetallic compound strengthening are more stable at high temperatures than carbide strengthening of Co and Mo, and are less prone to over-aging. This allows the cobalt-based alloy to still have excellent mechanical properties, strength and wear resistance at high temperatures. Attached Figure Description
[0028] Figure 1 This is a microstructure diagram of the cobalt-based alloy in the embodiments of this application. Detailed Implementation
[0029] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.
[0030] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.
[0031] In one aspect of the present disclosure, a cobalt-based alloy is provided, comprising by weight percentage (wt%): Cr 1-40%, Mo 1-40%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0032] With a maximum carbon content of 0.1%, compared to traditional cobalt-based alloys, the carbon content of cobalt-based alloys is reduced, avoiding the formation of a large number of brittle carbides, making cobalt-based alloy materials less prone to cracking when subjected to impact loads.
[0033] In addition, cobalt-based alloys have a low carbon content. During the process of preparing parts using cobalt-based alloy powder by pressing and sintering, decarburization is slight and will not cause a deterioration in the mechanical properties and strength of the parts.
[0034] In addition, the Mo content is as high as 40%, and the matrix Co is strengthened by solid solution through extremely high molybdenum content, supplemented by intermetallic compounds (Cr and Si). Solid solution strengthening and intermetallic compound strengthening are more stable at high temperatures than the carbide strengthening of Co and Mo, and are not prone to over-aging, so that the cobalt-based alloy still has excellent mechanical properties, strength and wear resistance at high temperatures.
[0035] Moreover, the Cr content is as high as 40%, which gives the cobalt-based alloy excellent oxidation resistance and corrosion resistance.
[0036] from Figure 1 As can be seen, the cobalt-based alloy in this embodiment exhibits a chrysanthemum-like Laves phase in its metallographic structure. This phase improves the wear resistance of the material, enabling the cobalt-based alloy to maintain excellent mechanical properties, strength, and wear resistance at high temperatures.
[0037] Furthermore, the cobalt-based alloy comprises, by weight percentage (wt%): Cr 2-15%, Mo 12-35%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0038] The Mo content is capped at 35% to avoid excessive molybdenum, which would make processing extremely difficult and could potentially form harmful phases.
[0039] In addition, the Cr content is not less than 2% and not more than 15%, which avoids the problem of insufficient oxidation resistance in materials with too little chromium, while too much chromium will consume the molybdenum needed to form the strengthening phase.
[0040] Therefore, cobalt-based alloys prepared using raw materials within the above percentage range exhibit excellent oxidation resistance, corrosion resistance, machinability, high-temperature mechanical properties, strength, toughness, and wear resistance. The material's performance indicators are well-balanced, with no obvious shortcomings.
[0041] Preferably, by weight percentage (wt%), it comprises: Cr 5-10%, Mo 25-30%, Si 1-5%, C 0-0.1%, with the balance being Co.
[0042] The Mo content is further limited to a maximum of 30%, effectively avoiding the extreme difficulty in processing and the potential formation of harmful phases caused by excessive molybdenum.
[0043] In addition, the Cr content is not less than 5% and not more than 10%, which effectively avoids the problem of insufficient oxidation resistance in materials with too little chromium, while too much chromium will consume the molybdenum required to form the strengthening phase.
[0044] Therefore, cobalt-based alloys prepared using raw materials within the above percentage range exhibit superior oxidation resistance, corrosion resistance, machinability, high-temperature mechanical properties, strength, toughness, and wear resistance. The material's performance indicators are more balanced, with no weaknesses, representing the optimal chemical composition balance point for cobalt-based alloys.
[0045] Furthermore, in another aspect of the embodiments of this disclosure, an alloy powder is provided, wherein the alloy powder material is a cobalt-based alloy of any of the foregoing.
[0046] By adopting the above technical solution, the alloy powder obtained is used to prepare parts by pressing and sintering. During this process, the parts are slightly decarburized, and their mechanical properties and strength are not reduced. Moreover, the parts have excellent oxidation resistance, corrosion resistance, machinability, mechanical properties at high temperature, strength, toughness, and wear resistance, and the performance indicators are relatively balanced.
[0047] In this embodiment, the alloy powder, when used in the powder metallurgy pressing and sintering process, has an oxygen content of less than 1500 ppm, compared to the traditional 2000-3000 ppm. The sintered parts show slight decarburization and a 70% improvement in high-temperature wear resistance.
[0048] Furthermore, in another aspect disclosed in this embodiment, a method for manufacturing alloy powder is proposed, comprising: S1. Mix Cr, Mo, Si, C and Co, heat under an inert atmosphere until melted, and stir evenly to form an alloy liquid; S2. Atomize the molten alloy into alloy powder.
[0049] Heating under an inert atmosphere can prevent material oxidation, and the temperature must be strictly controlled during the heating process to avoid burning of the raw materials.
[0050] In practice, the temperature in S1 is heated to the melting point of 1400-1750℃ to ensure that the cobalt-based alloy raw material is fully melted.
[0051] Specifically, the atomization methods in S2 include water atomization and gas atomization, so that different atomization methods can be used to prepare alloy powder according to production needs.
[0052] When the atomization method is water atomization, the method for manufacturing the alloy powder further includes: S3. Collect and dehydrate the alloy powder, then dry, sieve, and batch to obtain alloy powder with uniform particle size and excellent quality.
[0053] Because the atomized powder and water mixture (slurry) are mixed together, it is necessary to first separate most of the water from the powder to obtain wet powder; Next, the wet powder is dried at a low temperature to completely remove physically adsorbed water, while low-temperature drying can prevent powder oxidation.
[0054] The dried powder will have a certain particle size distribution, so it needs to be graded.
[0055] To ensure that the chemical composition and physical properties of the powder are uniform across batches, it is necessary to mix multiple batches of qualified powder.
[0056] The method for manufacturing alloy powder will be described in detail below through a specific embodiment.
[0057] In this embodiment, the method for manufacturing alloy powder includes: 1. Smelting: Cr, Mo, Si, C and Co raw materials are heated in a medium frequency induction furnace to above their melting point, with the temperature controlled at 1400-1750 degrees to form a uniform and pure metal melt. During this stage, the smelting temperature and atmosphere are strictly controlled to prevent element burn-off and oxidation.
[0058] 2. Water Atomization: The refined molten metal is steadily poured through a tund located at the bottom of the crucible, forming a fine stream of molten metal. Simultaneously, at the atomizing nozzle, a high-pressure water jet of 10 to 35 MPa violently impacts the falling molten metal stream from the spray plate. The immense kinetic energy of the high-pressure water jet tears and shears the continuous molten metal stream into countless tiny droplets. The large specific surface area causes these droplets to be rapidly cooled by the surrounding water medium, instantly solidifying into solid powder particles. The cooling rate is extremely high, typically reaching 10... 3 ~10 6 K / s, which helps to form fine microstructures.
[0059] 3. Collection and dehydration: The mixture of atomized powder and water (slurry) flows into the collection tank together. Then, most of the water is initially separated from the powder by means of suction filtration, centrifugation or screw conveying to obtain wet powder.
[0060] 4. Drying: The wet powder containing residual moisture is sent into a vacuum drying oven and dried at a low temperature to completely remove physically adsorbed water. At the same time, the low temperature helps to prevent powder oxidation.
[0061] 5. Sieving and Batch Combining: The dried powder will have a certain particle size distribution. A vibrating sieve or air classifier is used to classify the powder according to the required particle size range (e.g., -100 mesh, -300 mesh, etc.). In addition, to ensure uniform chemical composition and physical properties between batches, multiple batches of qualified powder are usually mixed in a batch combining machine.
[0062] In this embodiment, the heating temperature is controlled above 1400°C in order to fully dissolve the raw materials.
[0063] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0064] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A cobalt-based alloy, characterized in that: The composition by weight percentage (wt%) includes: Cr 1-40%, Mo 1-40%, Si 1-5%, C 0-0.1%, with the balance being Co.
2. The cobalt-based alloy according to claim 1, characterized in that: The composition by weight percentage (wt%) includes: Cr 2-15%, Mo 12-35%, Si 1-5%, C 0-0.1%, with the balance being Co.
3. The cobalt-based alloy according to claim 2, characterized in that: The composition by weight percentage (wt%) includes: Cr 5-10%, Mo 25-30%, Si 1-5%, C 0-0.1%, with the balance being Co.
4. An alloy powder, characterized in that: The alloy powder material is a cobalt-based alloy according to any one of claims 1-3.
5. The method for manufacturing the alloy powder according to claim 4, characterized in that, include: Cr, Mo, Si, C and Co are mixed and heated under an inert atmosphere until melted, and stirred evenly to form an alloy liquid; The molten alloy is atomized into alloy powder.
6. The manufacturing method according to claim 5, characterized in that: The temperature at which the material is heated to melt is 1400-1750℃.
7. The manufacturing method according to claim 5, characterized in that: The atomization methods include water atomization and air atomization.
8. The manufacturing method according to claim 7, characterized in that: When the atomization method is water atomization, the method for manufacturing the alloy powder further includes: The alloy powder is collected and dehydrated, then dried, sieved, and batched.
9. The manufacturing method according to claim 8, characterized in that: The drying process is low-temperature drying.
10. The manufacturing method according to claim 8, characterized in that: The water flow pressure during water atomization is 10 to 35 MPa.