Manufacturing method of sintered magnets
Databases and component prediction formulas allow precise selection and mixing of raw and auxiliary alloys to achieve desired compositions in sintered magnets, addressing variability and oxidation issues.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- PROTERIAL LTD
- Filing Date
- 2022-09-27
- Publication Date
- 2026-07-22
AI Technical Summary
The composition of auxiliary alloy powder can vary due to its derivation from different raw alloys and manufacturing process history, and oxidation during storage, making it difficult to objectively determine the mixing ratio needed to achieve the desired composition for sintered magnets.
A method involving databases to read and predict the composition of mixed fine powders by selecting raw and auxiliary alloys based on attribute information, using component prediction formulas and machine learning to ensure the composition falls within a predetermined range.
Enables accurate and objective determination of mixing ratios for sintered magnet production, reducing reliance on human experience and ensuring consistent magnetic properties.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for manufacturing a sintered magnet.
Background Art
[0002] An R-T-B sintered magnet (R is a rare earth element, including at least one selected from the group consisting of Nd, Pr, and Ce, T is at least one transition metal and necessarily includes Fe, and B is boron), which is a representative example of rare earth sintered magnets, consists of a main phase of a compound having a R2Fe 14 B-type crystal structure, a grain boundary phase located at the grain boundary portion of this main phase, and a compound phase generated by the influence of trace additive elements and impurities. The R-T-B sintered magnet has a high residual magnetic flux density B r (hereinafter, may be simply referred to as "B r ") and a high coercive force H cJ (hereinafter, may be simply referred to as "H cJ "), and is known as the highest performance magnet among permanent magnets due to its excellent magnetic properties. Therefore, R-T-B sintered magnets are used in various motors in the automotive field such as electric vehicles (EV, HV, PHV), the renewable energy field such as wind power generation, the household electric appliance field, and the industrial field.
[0003] Rare earth sintered magnets such as R-T-B sintered magnets are manufactured through steps of preparing alloy powder, press-forming the alloy powder to produce a formed body, and sintering the formed body. The alloy powder is produced, for example, by the following method.
[0004] First, raw alloys are manufactured from molten raw metals using methods such as strip casting. The obtained raw alloys are subjected to a grinding process to obtain raw alloy powder having a predetermined particle size distribution. This grinding process usually includes a coarse grinding process and a fine grinding process. The former is carried out, for example, by a "hydrogen grinding process" that utilizes the hydrogen embrittlement phenomenon. The latter is carried out, for example, by using an air-jet grinder (jet mill). The sintered body obtained by the process of sintering the molded body is then subjected to mechanical processing such as grinding and cutting to form individual pieces.
[0005] It is common practice to mix powders of alloys used for composition adjustment (auxiliary alloys) with powders of raw material alloys (main raw material alloys) produced by methods such as strip casting. For example, if the composition ratio of aluminum (Al) differs for each type, instead of preparing raw material alloys with different Al composition ratios for each type, it is possible to prepare auxiliary alloys containing Al at a relatively high concentration or auxiliary alloys containing Al at a relatively low concentration, and then select one of these auxiliary alloys and mix it with the raw material alloy powder (main raw material alloy) in an appropriate mixing ratio to prepare a mixed fine powder with the desired Al composition ratio. However, generally, the composition ratios of elements other than Al may differ between the raw material alloy and multiple auxiliary alloys. In such cases, selecting the main raw material alloy and auxiliary alloys and determining the mixing ratio to ultimately achieve the desired composition is not easy.
[0006] Alternatively, to obtain a high degree of orientation, a method may be used in which a main alloy (first alloy powder) and an auxiliary alloy (second alloy powder) are mixed to obtain the desired composition.
[0007] Auxiliary alloy powders can sometimes be produced from defective products generated during the powder molding process, or from powder (residue) remaining in the cavities of press molding machines. These defective products and residual powders are sintered, then subjected to a coarse grinding process, and then mixed in a certain amount with strip-cast alloys for use. By reusing alloy powders generated during the manufacturing process instead of discarding them, the wasteful consumption of scarce resources is reduced, and manufacturing costs can be lowered.
[0008] Patent Document 1 discloses a method for producing a molded body by mixing two types of alloy fine powders with different compositions and using the resulting mixed powder. [Prior art documents] [Patent Documents]
[0009] [Patent Document 1] Japanese Patent Publication No. 2006-249456 [Overview of the initiative] [Problems that the invention aims to solve]
[0010] The composition of auxiliary alloy powder can vary not only depending on the composition of the raw alloy from which the auxiliary alloy is derived, but also on the manufacturing process history until reuse. Furthermore, the composition of auxiliary alloy powder may change over time due to oxidation during storage. For this reason, when mixing auxiliary alloy powder with the main raw material powder, the decision of which auxiliary alloy to select from among several auxiliary alloys with diverse compositions, and the determination of the mixing ratio, have traditionally been based on the experience of skilled workers. Consequently, there was a problem in that it was not possible to objectively determine whether the desired composition could be achieved with that mixing ratio until the main raw material powder and auxiliary alloy powder were actually mixed and a compositional analysis was performed.
[0011] Embodiments of this disclosure provide a method for manufacturing a sintered magnet that enables solving the above-mentioned problems. [Means for solving the problem]
[0012] A method for manufacturing a sintered magnet according to the present disclosure, in a non-limiting and exemplary embodiment, includes the steps of: determining a target composition of alloy fine powder for a sintered magnet to be manufactured; selecting a raw material alloy to be used from a plurality of raw material alloys and selecting at least one auxiliary alloy to be used from a plurality of auxiliary alloys based on the target composition; determining a blending ratio between the selected raw material alloy and the selected at least one auxiliary alloy; and producing a mixed fine powder of the raw material alloy powder and the auxiliary alloy powder based on the blending ratio. The step of determining the blending ratio includes the steps of: reading the main raw material attribute information and the auxiliary alloy attribute information from a main raw material database storing main raw material attribute information including the composition of each of the plurality of raw material alloys and an auxiliary alloy database storing auxiliary alloy attribute information including the composition of each of the plurality of auxiliary alloys; predicting the composition of the mixed fine powder obtained when the selected raw material alloy powder and the selected auxiliary alloy powder are mixed at the blending ratio based on the main raw material attribute information and the auxiliary alloy attribute information; and determining whether the predicted composition falls within a predetermined range. [Effects of the Invention]
[0013] According to embodiments of this disclosure, calculations based on compositional information contained in a database make it possible to mix auxiliary alloys recovered during the manufacturing process of sintered magnets with the raw alloys in a blending ratio that matches the desired composition, without relying on the experience or intuition of skilled workers. [Brief explanation of the drawing]
[0014] [Figure 1] Figure 1 is a schematic diagram illustrating an example of "recovery" in the manufacturing process of sintered magnets. [Figure 2] Figure 2 schematically shows sets composed of multiple main raw material alloys SC-1, ..., SC-m, and sets composed of multiple auxiliary alloys RS-1, ..., RS-j, RS-(j+1), ..., RS-n. [Figure 3] Figure 3 is a flowchart showing the main steps in the method for manufacturing a sintered magnet according to the present disclosure. [Figure 4] FIG. 4 is a flowchart showing the main steps in the method for manufacturing a sintered magnet of the present disclosure. [Figure 5] FIG. 5 is a flowchart showing the main steps in the method for manufacturing a sintered magnet of the present disclosure. [Figure 6] FIG. 6 is a diagram schematically showing an embodiment of an alloy composition determination system for a sintered magnet.
DETAILED DESCRIPTION OF THE INVENTION
[0015] In the method for manufacturing a sintered magnet of the present disclosure, powders recovered during the manufacturing process of the sintered magnet, cracks and chips in the compacts, etc. are reused.
[0016] FIG. 1 is a diagram schematically showing an example of "recovery" in the manufacturing process of a sintered magnet. In the example of FIG. 1, the manufacturing of the sintered magnet proceeds by sequentially performing the following steps.
[0017] First, raw material alloy is received by receiving the alloy. The raw material alloy is embrittled by hydrogen treatment and coarsely crushed (coarse pulverization). Further, fine pulverization is performed using a jet mill device or the like. The powder produced by fine pulverization is formed by pressing in a magnetic field or the like to obtain a powder compact. The powder compact is sintered in a sintering furnace to obtain a sintered body (sintered magnet material). After performing heat treatment for improving magnet properties, it is subjected to mechanical processing such as cutting and polishing to obtain a sintered magnet having a desired shape and size. Further, after performing surface treatment such as plating, it is shipped after passing through an appearance inspection.
[0018] Before and after each of these steps, solid materials that cannot be used for the product are recovered as solid recycled raw materials from cracks, chips, dimensional defects, coating defects, etc. Such solid recycled raw materials can be used in the production of the raw material alloy or stored in a plurality of packs as powdered auxiliary alloys in predetermined weight units.
[0019] In the manufacturing process of sintered magnets, there are also recycled raw materials that are not recovered as the above solid recycled raw materials but are recovered in other forms. In the example of FIG. 1, the ultrafine powder generated by fine pulverization is recovered as fired powder through atmospheric firing. During processing, polishing powder is generated and can be recovered as polishing sludge. After surface treatment, defective products due to oil adhesion, rust, adhesives, etc. are recovered. After visual inspection, defective magnetized products can be recovered. These recovered materials can be used for raw material production. In the molding process, the feeder powder recovered when feeding the powder into the press and the arranging machine powder generated when taking out the molded body and placing it on the table can be recovered as solid recycled raw materials after being used as getter materials in the sintering process.
[0020] In an embodiment of the present disclosure, the powder of the auxiliary alloy is blended with the powder of the raw material alloy (main raw material alloy) and reused in the production of sintered magnets. FIG. 2 schematically shows a set composed of a plurality of raw material alloys SC-1, ···, SC-m and a set composed of a plurality of auxiliary alloys RS-1, ···, RS-j, RS-(j + 1), ···, RS-n. Here, m, n, and j are integers of 2 or more, and j < n.
[0021] The raw material alloy is, for example, an alloy produced by the strip casting method. The composition of each of the raw material alloy and the auxiliary alloy is specified by analysis. As described above, since the auxiliary alloy is a material obtained by recovering the solids generated in each process during production, its composition, particularly the oxygen concentration, can vary greatly depending on the auxiliary alloy. Since the magnet characteristics of the sintered magnet largely depend on the composition of the alloy fine powder used in production, the target composition differs depending on the type of sintered magnet to be produced. Therefore, it is required to appropriately select the raw material alloy from a plurality of raw material alloys SC-1, ···, SC-m and appropriately select the auxiliary alloy from a plurality of auxiliary alloys RS-1, ···, RS-n according to the target composition.
[0022] Table 1 below describes an example of information including the composition regarding the auxiliary alloy.
[0023]
Table 1
[0024] The following is an example of a compound composition where the following alloys are selected. (1) Raw material alloy SC-5: composition A1, weight B1 (2) Auxiliary alloy RS-128: composition A2, weight B2 (3) Auxiliary alloy RS-155: composition A3, weight B3 Here, the mixing ratio of each element is obtained by multiplying the mass ratio of the elements contained in each alloy by the weighting coefficients B1 / (B1+B2+B3), B2 / (B1+B2+B3), and B3 / (B1+B2+B3), and then calculating the sum. Here, B1 / (B1+B2+B3), B2 / (B1+B2+B3), and B3 / (B1+B2+B3) are expressed as mixing ratios β1, β2, and β3, respectively.
[0025] Table 2 below shows specific examples of predicted and measured values for the composition of each alloy and the composition of the mixture. In this example, B1=380, B2=10, and B3=20. α1 and α2 represent any element other than Nd, Dy, and Al. In the disclosed embodiment, the composition of the mixed fine powder obtained by mixing the powder of the selected raw material alloy and the powder of the selected auxiliary alloy at a predetermined mixing ratio is calculated and predicted based on the component prediction calculation formula described later. Then, it is determined whether or not the predicted composition falls within a predetermined range.
[0026] [Table 2]
[0027] The predicted values can be calculated using the following component prediction formula (Equation 1), which includes the symbols shown in Table 3.
[0028] [Table 3]
number
[0029] Row vectors containing the predicted composition ratios Y1, Y2, Y3, and Y4 after mixing the auxiliary alloy with the raw alloy are obtained by multiplying a matrix whose elements are the composition ratios of each raw material by row vectors containing the blending ratios β1, β2, and β3 from the left.
[0030] In the example above, the 3x4 matrix represents the composition ratios of each element contained in the raw alloy and auxiliary alloy. The number of rows in the matrix corresponds to the number of alloys used in the mixture, and the number of columns corresponds to the types of elements whose composition is calculated. Therefore, the number of rows and columns in the matrix is not limited to the example above and can be arbitrary.
[0031] Taking the transpose of the equation shown in Equation 1, we obtain Equation 2. Equation 2 is a component prediction calculation formula equivalent to Equation 1.
[0032]
number
[0033] If the predicted value obtained in this way (the composition ratio after mixing the raw alloy and auxiliary alloy) falls within a predetermined range relative to the target composition ratio, it is determined that there is no need to modify the above mixing ratio. If the predicted value obtained by the calculation falls outside this predetermined range, the mixing ratio is changed or the selection of auxiliary alloy is redone. Such modifications are carried out by repeated computer calculations, resulting in the selection of the most preferable auxiliary alloy and determination of the mixing ratio.
[0034] As shown in the example in Table 2 above, there is a slight difference between the predicted values obtained by such calculations and the measured values obtained from the analysis of the mixed powder. This difference was found to depend on the type of alloy used in the mixing and the grinding equipment. This is because a change in composition occurs during the process in which the raw material alloy and auxiliary alloy are transformed into fine powders within the grinding equipment. Such a change in composition occurs because there are parts of the alloy structure that are easily fractured by grinding and parts that are not easily fractured, and the abundance ratio of elements differs in these parts. In the grinding process, ultrafine powders with particle sizes on the submicron order may not be used as raw material alloy powder but can be recovered as recycled material (Figure 1). As a result, the composition ratio after grinding may deviate from the predicted value.
[0035] Therefore, in this embodiment, not only predicted and measured values, but also information identifying the grinding device is stored in the database. With such a database, the trend of the difference between predicted and measured values can be determined for each grinding device, making it possible to obtain effective training data when correcting predicted values using a machine learning model. Then, by using a trained model created using such training data, it becomes possible to correct the above predicted values and make predictions that are more accurate to the measured values.
[0036] Furthermore, since each of the multiple auxiliary alloys RS-1, ..., RS-n was recovered and manufactured at different times, the elapsed time since each auxiliary alloy was placed in the pack may differ. For example, auxiliary alloy RS-1 may have been placed in the pack on January 10, 2022, while auxiliary alloy RS-j may have been placed in the pack on March 10, 2022. According to the inventors' considerations, auxiliary alloys of rare-earth sintered magnets, for example, in a powder state, may oxidize during long-term storage, leading to an increase in oxygen concentration. Therefore, in order to maintain the reliability of the composition obtained by analysis, it is preferable to select from the oldest auxiliary alloys when selecting from multiple auxiliary alloys. Specifically, if there are multiple auxiliary alloys that have practically the same composition, the older auxiliary alloy should be selected preferentially.
[0037] In the embodiments of this disclosure, auxiliary alloy attribute information is prepared for each of the auxiliary alloys RS-1, ..., RS-n, including their respective compositions, inventory information, the date on which the composition analysis was performed, or the number of days elapsed from that date to the present, and stored in a database (auxiliary alloy database). Similarly, for multiple raw material alloys SC-1, ..., SCm, main raw material alloy attribute information is prepared for each, including their respective compositions, inventory information, and the date on which the composition analysis was performed, and stored in a database (main raw material database). By using such databases, it becomes possible to reproduce the blending of raw material alloys and auxiliary alloys, which was conventionally done based on the experience and intuition of skilled technicians, using digitized electronic technology.
[0038] Furthermore, the auxiliary alloy attribute information obtained through analysis to determine the composition of auxiliary alloys is used to update the auxiliary alloy database as needed.
[0039] Figures 3 to 5 are flowcharts showing the main steps in the method for manufacturing a sintered magnet according to the present disclosure. As shown in Figure 3, in the method for manufacturing a sintered magnet according to the present disclosure, first, in step S12, a step is performed to determine the target composition of the alloy fine powder for the sintered magnet to be manufactured. The target composition is, for example, Nd: 22.50 [wt%], Dy: 4.00 [wt%], and ·Al: 0.20 [wt%].
[0040] Next, in step S14, the process of determining the blending ratio based on the target composition is performed. Specifically, as shown in Figure 4, a raw material alloy to be used (main raw material alloy) is selected from multiple raw material alloys based on the target composition (step S14A). Also, an auxiliary alloy to be used is selected from multiple auxiliary alloys based on the target composition (step S14B). Then, the blending ratio between the selected raw material alloy and at least one selected auxiliary alloy is determined (step S14C). A more detailed explanation of the process of determining the blending ratio will be given later.
[0041] Refer to Figure 3 again. In step S16, a process is carried out to produce a mixed fine powder of the raw material alloy powder and the auxiliary alloy powder based on the mixing ratio determined in step S14.
[0042] The step S14C for determining the blending ratio in Figure 4 includes a step S18A for reading main raw material attribute information and auxiliary alloy attribute information from a database, as shown in Figure 5. Here, "main raw material attribute information" refers to information about the attributes of the main raw materials, including the composition of each of the multiple raw material alloys. "Auxiliary alloy attribute information" refers to information about the attributes of the auxiliary alloys, including the composition of each of the multiple auxiliary alloys. The database includes a main raw material database that stores the main raw material attribute information and an auxiliary alloy database that stores the auxiliary alloy attribute information. However, the main raw material database and the auxiliary alloy database may consist of data stored in the same storage device.
[0043] As shown in Figure 5, the step of determining the blending ratio (step S14 in Figure 3) further includes step S18B, which predicts the composition of the mixed fine powder obtained when the selected raw material alloy powder and the selected auxiliary alloy powder are mixed in the blending ratio, based on the main raw material attribute information and the auxiliary alloy attribute information, and determines whether the predicted composition falls within the predetermined range. If it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range, one or all of the raw material alloy and auxiliary alloy used are changed. Since the auxiliary alloy (scrap alloy) is divided into predetermined weight units, when the auxiliary alloy powder is mixed with the raw material alloy powder, the auxiliary alloy powder is blended in an integer multiple of the weight unit. Therefore, if it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range, one or all of the selected auxiliary alloys will be changed by an integer multiple of the weight unit.
[0044] The step of determining whether the predicted composition of the mixed fine powder falls within a predetermined range includes the step of reading the latest auxiliary alloy attribute information for the selected auxiliary alloy from the auxiliary alloy database.
[0045] When predicting the composition of a mixed fine powder, a component prediction formula is used that depends on the composition contained in the main raw material attribute information and auxiliary alloy attribute information, as well as the mixing ratio. The component prediction formula can be corrected depending on the grinding equipment used. In a preferred embodiment, grinding is performed after mixing the raw material alloy and the auxiliary alloy.
[0046] Furthermore, recent composition data for a given product number can be recorded in a database, and the type of auxiliary alloy and the mixing ratio of the raw alloy to the auxiliary alloy can be adjusted to achieve a composition equivalent to that data. Additionally, if recent composition data and magnetic properties for a given product number are recorded in the database, the mixing ratio can be adjusted to bring the previous magnetic properties closer to the middle of the specified range if they were near the upper or lower limit.
[0047] Figure 6 is a schematic diagram illustrating an embodiment of a system for determining the alloy composition of sintered magnets.
[0048] The alloy composition determination system 100 for sintered magnets in the example shown in the figure includes: an input device 10 that receives input of the properties of the sintered magnet to be manufactured or the target composition of the alloy powder for the sintered magnet; a computer device 20 that, based on the properties or target composition, selects a raw material alloy to be used from a plurality of raw material alloys, and selects at least one auxiliary alloy to be used from a plurality of auxiliary alloys, and determines the blending ratio between the selected raw material alloy and the selected at least one auxiliary alloy; a main raw material database 30 that stores main raw material attribute information including the composition of each of the plurality of raw material alloys; and an auxiliary alloy database 40 that stores auxiliary alloy attribute information including the composition of each of the plurality of auxiliary alloys. In the example shown in the figure, these may be connected via a communication network 50. The computer device 20 is configured to read the main raw material attribute information and auxiliary alloy attribute information from the main raw material database 30 and the auxiliary alloy database 40, and to calculate the blending ratio based on the main raw material attribute information and auxiliary alloy attribute information so that the composition of the mixed powder falls within a predetermined range including the target composition. The calculation of the blending ratio may be achieved by any algorithm that performs the method described above.
[0049] As described above, this disclosure includes a method for manufacturing sintered magnets and an alloy composition determination system as described in the following items.
[0050] [Item 1] A process for determining the target composition of the alloy fine powder for the sintered magnet to be manufactured, A step of selecting a raw material alloy to be used from a plurality of raw material alloys based on the target composition, and selecting at least one auxiliary alloy to be used from a plurality of auxiliary alloys, and determining the blending ratio between the selected raw material alloy and the selected at least one auxiliary alloy, A step of preparing a mixed fine powder of the raw material alloy powder and the auxiliary alloy powder based on the aforementioned mixing ratio, Includes, The step of determining the aforementioned blending ratio is: A step of reading the main raw material attribute information and the auxiliary alloy attribute information from a main raw material database which stores main raw material attribute information including the composition of each of the multiple raw material alloys, and an auxiliary alloy database which stores auxiliary alloy attribute information including the composition of each of the multiple auxiliary alloys. A step of predicting the composition of the mixed fine powder obtained when the selected raw material alloy powder and the selected auxiliary alloy powder are mixed in the aforementioned blending ratio, based on the aforementioned main raw material attribute information and the aforementioned auxiliary alloy attribute information, and determining whether the predicted composition falls within a predetermined range. A method for manufacturing sintered magnets, including [the specified part of the invention].
[0051] [Item 2] The aforementioned raw material alloy is an alloy produced by the strip casting method. The method for manufacturing a sintered magnet according to item 1, wherein some or all of the aforementioned auxiliary alloys are scrap alloys recovered during the manufacturing process of the sintered magnet.
[0052] [Item 3] The aforementioned scrap alloy is divided into predetermined weight units, The method for manufacturing a sintered magnet according to item 2, wherein when the powder of the auxiliary alloy is mixed with the powder of the raw material alloy, the powder of the auxiliary alloy is blended in an amount that is an integer multiple of the weight unit.
[0053] [Item 4] A step of performing an analysis to determine the composition of the aforementioned multiple auxiliary alloys, A step of storing the latest auxiliary alloy attribute information, including the compositions of the multiple auxiliary alloys obtained by the above analysis, in the auxiliary alloy database, A method for manufacturing a sintered magnet as described in item 3, including the method described in item 3.
[0054] [Item 5] The method for manufacturing a sintered magnet as described in item 4, wherein the auxiliary alloy attribute information includes, for each of the plurality of auxiliary alloys, inventory information and information on the date on which the analysis to determine the composition was performed, or the number of days that have elapsed from that date to the present.
[0055] [Item 6] A method for manufacturing a sintered magnet according to any one of items 1 to 5, comprising the step of changing one or all of the raw material alloy and auxiliary alloy used if it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range.
[0056] [Item 7] The method for manufacturing a sintered magnet according to item 6, wherein if it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range, one or all of the selected auxiliary alloys are changed by an integer multiple of the weight unit.
[0057] [Item 8] The step of determining whether the predicted composition of the mixed fine powder falls within the predetermined range is as follows: A method for manufacturing a sintered magnet according to item 6, comprising the step of reading the latest auxiliary alloy attribute information relating to the selected auxiliary alloy from the auxiliary alloy database.
[0058] [Item 9] A method for manufacturing a sintered magnet according to any one of items 6 to 8, wherein when predicting the composition of the mixed fine powder, a component prediction calculation formula is used that depends on the composition included in the main raw material attribute information and the auxiliary alloy attribute information, and the blending ratio.
[0059] [Item 10] The method for manufacturing a sintered magnet as described in item 9, wherein the component prediction calculation formula is corrected according to the grinding apparatus used.
[0060] [Item 11] The step of determining whether the predicted composition falls within the predetermined range is as follows: A method for manufacturing a sintered magnet as described in any one of items 1 to 5, which is performed using a trained model that takes the composition before grinding and the grinding equipment as input and outputs the composition after grinding.
[0061] [Item 12] An input device that accepts input of the characteristics of the sintered magnet to be manufactured, or the target composition of the alloy fine powder for the sintered magnet, A computer device that, based on the aforementioned characteristics or the aforementioned target composition, selects a raw material alloy to be used from a plurality of raw material alloys, selects at least one auxiliary alloy to be used from a plurality of auxiliary alloys, and determines the blending ratio between the selected raw material alloy and the selected at least one auxiliary alloy. A main raw material database storing main raw material attribute information including the composition of each of the aforementioned multiple raw material alloys, A subsidiary alloy database storing subsidiary alloy attribute information including the composition of each of the aforementioned plurality of subsidiary alloys, Equipped with, The aforementioned computer device, From the main raw material database and the auxiliary alloy database, read out the main raw material attribute information and the auxiliary alloy attribute information. Based on the attribute information of the main raw material and the attribute information of the auxiliary alloy, the blending ratio is calculated such that the composition of the mixed fine powder falls within a predetermined range including the target composition. A system for determining the alloy composition of sintered magnets. [Industrial applicability]
[0062] The method for manufacturing the sintered magnets of the present disclosure can be widely used in the field of manufacturing sintered magnets containing rare resource elements in the raw material alloy.
Claims
1. A process for determining the target composition of the alloy fine powder for the sintered magnet to be manufactured, A step of selecting a raw material alloy to be used from a plurality of raw material alloys based on the target composition, and selecting at least one auxiliary alloy to be used from a plurality of auxiliary alloys, and determining the blending ratio between the selected raw material alloy and the selected at least one auxiliary alloy, A step of preparing a mixed fine powder of the raw material alloy powder and the auxiliary alloy powder based on the aforementioned mixing ratio, Includes, The aforementioned raw material alloy is an alloy produced by the strip casting method. Some or all of the aforementioned auxiliary alloys are scrap alloys recovered during the manufacturing process of sintered magnets. The aforementioned scrap alloy is divided into predetermined weight units, When the auxiliary alloy powder is mixed with the raw material alloy powder, the auxiliary alloy powder is blended in an integer multiple of the weight unit. The step of determining the aforementioned blending ratio is: A step of reading the main raw material attribute information and the auxiliary alloy attribute information from a main raw material database which stores main raw material attribute information including the composition of each of the multiple raw material alloys, and an auxiliary alloy database which stores auxiliary alloy attribute information including the composition of each of the multiple auxiliary alloys. A step of predicting the composition of the mixed fine powder obtained when the selected raw material alloy powder and the selected auxiliary alloy powder are mixed in the aforementioned blending ratio, based on the aforementioned main raw material attribute information and the aforementioned auxiliary alloy attribute information, and determining whether the predicted composition falls within a predetermined range. A method for manufacturing sintered magnets, including [the specified part of the invention].
2. A step of performing an analysis to determine the composition of the aforementioned multiple auxiliary alloys, A step of storing the latest auxiliary alloy attribute information, including the compositions of the multiple auxiliary alloys obtained by the above analysis, in the auxiliary alloy database, A method for manufacturing a sintered magnet according to claim 1, including the method described in claim 1.
3. The method for manufacturing a sintered magnet according to claim 2, wherein the auxiliary alloy attribute information includes, for each of the plurality of auxiliary alloys, inventory information and information on the date on which the analysis to determine the composition was performed, or the number of days that have elapsed from that date to the present.
4. A method for manufacturing a sintered magnet according to any one of claims 1 to 3, comprising the step of changing one or all of the raw material alloy and auxiliary alloy used if it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range.
5. If it is determined that the predicted composition of the mixed fine powder does not fall within the predetermined range, the method for manufacturing a sintered magnet according to claim 4, wherein one or all of the selected auxiliary alloys are changed by an integer multiple of the weight unit.
6. The step of determining whether the predicted composition of the mixed fine powder falls within the predetermined range is as follows: A method for manufacturing a sintered magnet according to claim 4, comprising the step of reading the latest auxiliary alloy attribute information relating to the selected auxiliary alloy from the auxiliary alloy database.
7. The method for manufacturing a sintered magnet according to claim 5, wherein when predicting the composition of the mixed fine powder, a component prediction calculation formula is used that depends on the composition included in the main raw material attribute information and the auxiliary alloy attribute information, and the blending ratio.
8. The method for manufacturing a sintered magnet according to claim 7, wherein the component prediction calculation formula is corrected according to the grinding apparatus used.
9. The step of determining whether the predicted composition falls within the predetermined range is as follows: A method for manufacturing a sintered magnet according to any one of claims 1 to 3, which is performed using a trained model that takes the composition before grinding and the grinding equipment as input and outputs the composition after grinding.