Sintered member, and method for manufacturing a sintered member

Abstract

A sintered member composed of a metal, wherein the sintered member has a relative density of 95% or greater and has at least one of a hole for which the diameter x1 (mm) and depth y1 (mm) satisfy specific requirements and a groove for which the width x2 (mm) and depth y2 (mm) satisfy specific requirements.

Description

Technical Field

[0001] The present disclosure relates to a sintered member and a method for manufacturing a sintered member. This application claims priority based on Japanese Patent Application No. 2022-071901 filed on April 25, 2022, and incorporates all the content described in said Japanese application by reference.

Background Art

[0002] The method for manufacturing a sintered component disclosed in Patent Document 1 includes a step of press-molding raw material powder to produce a green compact, a step of forming a hole in the green compact, and a step of sintering the green compact with the hole formed therein. The raw material powder includes iron powder, copper powder, carbon powder, and ethylene bisstearic amide.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

[0004] The sintered member of the present disclosure is a sintered member made of metal, wherein the relative density is 95% or more, and it has at least one of a hole portion whose diameter x1 (mm) and depth y1 (mm) satisfy the following requirements (a1) to (a7), and a groove portion whose width x2 (mm) and depth y2 (mm) satisfy the following requirements (b1) to (b3). (a1) When 0.05 ≦ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) When 0.08 ≦ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) When 0.1 ≦ x1 < 0.3, y1 > 10x1 (a4) When 0.3 ≦ x1 < 0.8, y1 > 8x1 + 0.6 (a5) When 0.8 ≦ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20 (b1) In 0.05 ≤ x² < 0.2, y² > 5x² + 0.4 (b2) In the case of 0.2 ≤ x² < 0.5, y² > 28.7x² - 4.3 (b3) For 0.5 ≤ x², y² > 6x² + 7

[0005] The method for manufacturing a sintered member according to this disclosure is: A process of preparing raw material powder containing metal powder and lubricant, A step of pressurizing the raw material powder to produce a compacted molded body having a relative density of 95% or more, A process to produce a processed body having at least one of the following machining operations, a hole, and a groove, by performing a hole machining operation on the powder compacted body, the hole having a diameter x1 (mm) and a depth y1 (mm) that satisfies the following requirements (a1) to (a7), and a groove having a width x2 (mm) and a depth y2 (mm) that satisfies the following requirements (b1) to (b3), The process includes a step of sintering the processed body, The proportion of the lubricant contained in the raw material powder is 0.025% by mass or more and 0.2% by mass or less. The melting point of the lubricant is 150°C or lower. (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) In the case of 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) In 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20 (b1) In 0.05 ≤ x² < 0.2, y² > 5x² + 0.4 (b2) When 0.2≦x2<0.5, y2>28.7x2-4.3 (b3) When 0.5≦x2, y2>6x2+7 [BRIEF DESCRIPTION OF THE DRAWINGS]

[0006] [Figure 1] FIG. 1 is a schematic perspective view showing the sintered member of an embodiment. [Figure 2] FIG. 2 is a II-II cross-sectional view of FIG. 1. [Figure 3] FIG. 3 is a partial cross-sectional view showing another example of the sintered member of an embodiment. [Figure 4] FIG. 4 is a IV-IV cross-sectional view of FIG. 3. [Figure 5] FIG. 5 is a graph showing the relationship between the diameter and depth of holes in a sintered member produced in Test Example 1. [Figure 6] FIG. 6 is an enlarged graph of region A in FIG. 5. [Figure 7] FIG. 7 is an enlarged graph of region B in FIG. 6. [Figure 8] FIG. 8 is a graph showing the relationship between the width and depth of grooves in a sintered member produced in Test Example 2. [Figure 9] FIG. 9 is an enlarged graph of region C in FIG. 8. DESCRIPTION OF EMBODIMENTS

[0007] [Problem to be Solved by the Present Disclosure] There is a demand for production of a sintered member having a hole with a larger depth relative to its diameter or a groove with a larger depth relative to its width.

[0008] An object of the present disclosure is to provide a sintered member having a hole with a larger depth relative to its diameter or a groove with a larger depth relative to its width. Another object of the present disclosure is to provide a method for producing the above sintered member.

[0009] [Effects of the Present Disclosure] The sintered member of the present disclosure has a hole with a depth greater than its diameter, or a groove with a depth greater than its width. The method for producing a sintered member according to the present disclosure is capable of producing the sintered member of the present disclosure.

[0010] <<Description of Embodiments of the Present Disclosure>> First, embodiments of the present disclosure will be listed and described.

[0011] (1) The sintered member according to one aspect of the present disclosure is a sintered member made of metal, wherein the relative density is 95% or more, and the sintered member comprises at least one of: a hole of which a diameter x1 (mm) and a depth y1 (mm) satisfy the following requirements (a1) to (a7), and a groove of which a width x2 (mm) and a depth y2 (mm) satisfy the following requirements (b1) to (b3). (a1) when 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) when 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) when 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) when 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) when 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) when 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) when 2.0 ≤ x1, y1 > 10x1 + 20 (b1) when 0.05 ≤ x2 < 0.2, y2 > 5x2 + 0.4 (b2) when 0.2 ≤ x2 < 0.5, y2 > 28.7x2 - 4.3 (b3) when 0.5 ≤ x2, y2 > 6x2 + 7

[0012] The sintered member described above has a hole with a depth greater than its diameter, or a groove with a depth greater than its width.

[0013] (2) In the sintered member according to (1) above, the metal may be pure iron or an iron alloy.

[0014] The sintered member, made of pure iron or an iron alloy, has a hole with a depth that is greater than its diameter, or a groove with a depth that is greater than its width.

[0015] (3) In the sintered member described in (1) above, The aforementioned metal may be stainless steel.

[0016] The sintered member made of stainless steel has a hole portion with a depth that is greater than its diameter, or a groove portion with a depth that is greater than its width.

[0017] (4) A method for manufacturing a sintered member according to one aspect of the present disclosure is: A process of preparing raw material powder containing metal powder and lubricant, A step of pressurizing the raw material powder to produce a compacted molded body having a relative density of 95% or more, A process to produce a processed body having at least one of the following machining operations, a hole, and a groove, by performing a hole machining operation on the powder compacted body, the hole having a diameter x1 (mm) and a depth y1 (mm) that satisfies the following requirements (a1) to (a7), and a groove having a width x2 (mm) and a depth y2 (mm) that satisfies the following requirements (b1) to (b3), The process includes a step of sintering the processed body, The proportion of the lubricant contained in the raw material powder is 0.025% by mass or more and 0.2% by mass or less. The melting point of the lubricant is 150°C or lower. (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) In the case of 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) In 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20 (b1) In 0.05 ≤ x² < 0.2, y² > 5x² + 0.4 (b2) In the case of 0.2 ≤ x² < 0.5, y² > 28.7x² - 4.3 (b3) For 0.5 ≤ x², y² > 6x² + 7

[0018] The above method for manufacturing sintered members facilitates the spreading of lubricant between the particles of the compacted molded body by pressurizing raw material powder containing a lubricant with a melting point of 150°C or lower. Because the lubricant is spread between the particles of the compacted molded body, holes can be formed by drilling holes in the compacted molded body, and grooves can be formed by drilling grooves in the compacted molded body. The relative density of the compacted molded body and the relative density of the processed body are the same. Since the relative density of the manufactured compacted molded body is 95% or higher, the amount of shrinkage when the processed body is sintered is very small. Therefore, the size of the holes and grooves in the sintered member is substantially maintained from the size of the holes and grooves in the processed body. Thus, the above method for manufacturing sintered members can produce sintered members having holes with a large depth relative to their diameter, or grooves with a large depth relative to their width.

[0019] (5) In the method for manufacturing the sintered member described in (4) above, The lubricant may be stearic acid, erucic acid amide, or stearic acid amide.

[0020] The above lubricant is easily spread over a wide area between the particles of the compacted molded body by the pressurization of the raw material powder.

[0021] Details of the embodiments of this disclosure Embodiments of this disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same component. The dimensions of the components shown in each drawing are for illustrative purposes only and do not necessarily represent actual dimensional relationships.

[0022] 《Embodiment》 [Sintered material] The sintered member 1 of this embodiment will be described with reference to Figures 1 to 4. The sintered member 1 is made of metal. One of the features of the sintered member 1 of this embodiment is that it has a high relative density and has at least one of a hole portion 2 of a specific size and a groove portion 3 of a specific size.

[0023] [Material] The material of the sintered member 1 is metal. The metal may be, for example, pure iron, an iron alloy, or a non-ferrous metal.

[0024] Pure iron is iron with a purity of 99% or higher. In other words, pure iron is iron (Fe) with a mass of 99% or more.

[0025] An iron alloy is a material that contains additive elements, with the remainder being iron (Fe) and unavoidable impurities. Iron alloys contain the most abundant element, Fe. Additive elements in iron alloys include, for example, one or more elements selected from the group consisting of nickel (Ni), copper (Cu), chromium (Cr), molybdenum (Mo), manganese (Mn), carbon (C), silicon (Si), aluminum (Al), phosphorus (P), boron (B), nitrogen (N), and cobalt (Co). Specific examples of iron alloys include stainless steel, Fe-C alloys, Fe-Cu-Ni-Mo alloys, Fe-Ni-Mo-Mn alloys, Fe-P alloys, Fe-Cu alloys, Fe-Cu-C alloys, Fe-Cu-Mo alloys, Fe-Ni-Mo-Cu-C alloys, Fe-Ni-Cu alloys, Fe-Ni-Mo-C alloys, Fe-Ni-Cr alloys, Fe-Ni-Mo-Cr alloys, Fe-Cr alloys, Fe-Mo-Cr alloys, Fe-Cr-C alloys, Fe-Ni-C alloys, or Fe-Mo-Mn-Cr-C alloys. An example of stainless steel is austenitic stainless steel. An example of austenitic stainless steel is SUS304 or SUS304L.

[0026] Non-ferrous metals include, for example, copper, copper alloys, aluminum, or aluminum alloys.

[0027] The composition of sintered member 1 can be confirmed by performing component analysis using ICP emission spectrometry (ICP-OES).

[0028] [Relative density] The relative density of the sintered member 1 is 95% or higher. A sintered member 1 with a relative density of 95% or higher has excellent mechanical properties such as strength. The relative density of the sintered member 1 may be further 96% or higher, and especially 97% or higher. The upper limit of the relative density of the sintered member 1 is not particularly limited and can be appropriately selected within the range that can be manufactured. The relative density of the sintered member 1 may be, for example, 99.9% or lower. That is, the relative density of the sintered member 1 may be 95% or higher and 99.9% or lower, further 96% or higher and 99.9% or lower, and especially 97% or higher and 99.9% or lower.

[0029] The relative density of the sintered member 1 is the ratio (%) of the actual density of the sintered member 1 to the true density of the sintered member 1. That is, the relative density of the sintered member 1 is calculated by [(actual density of the sintered member 1 / true density of the sintered member 1) × 100]. The actual density of the sintered member 1 can be determined by immersing the sintered member 1 in oil to impregnate it with oil, and then calculating [oil-impregnated density × (mass of the sintered member 1 before oil impregnation / mass of the sintered member 1 after oil impregnation)]. The oil-impregnated density is (mass of the sintered member 1 after oil impregnation / volume of the sintered member 1 after oil impregnation). That is, the actual density of the sintered member 1 can be determined by (mass of the sintered member 1 before oil impregnation / volume of the sintered member 1 after oil impregnation). The volume of the sintered member 1 after oil impregnation can typically be measured by the liquid displacement method. The true density of the sintered member 1 is the theoretical density obtained from the composition of the sintered member 1, assuming that it does not contain any voids inside.

[0030] [Hole] The hole portion 2 is either a through hole or a blind hole. A blind hole has a bottom. The number of hole portions 2 is not particularly limited and can be selected as appropriate. If there are multiple hole portions 2, both through holes and blind holes may be provided. The hole portion 2 has a substantially uniform diameter in the direction along the depth of the hole portion 2.

[0031] The diameter x1 (mm) and depth y1 (mm) of hole 2 satisfy the following requirements (a1) to (a7). For details, please refer to Figures 5 to 7 and see Test Example 1. (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) In the case of 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) In 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20

[0032] The upper limit of the depth y1 (mm) of hole 2 relative to its diameter x1 (mm) depends, for example, on the tool's limit diameter and length, or the limit size of the compacted molded body during the manufacturing process. For example, commercially available drills used to form hole 2 typically have a ratio L / D of 20 or less or 30 or less, which is the ratio of the drill's flute length L (mm) to its diameter D (mm). Depending on the diameter D and the tool's material, even for drills specifically designed for drilling particularly deep holes, the L / D is said to be limited to 40 or less or 50 or less. For example, the upper limit of the depth y1 of hole 2 relative to its diameter x1 is at least 50 times the diameter x1 in all of the above (a1) to (a7). It is considered possible that the depth of hole 2 formed by the manufacturing method of the sintered member of this embodiment, described later, can be deeper than the hole drilled with an L / D=50 drill, to the extent that the drill can be used.

[0033] [Mizobe] The number of grooves 3 is not particularly limited and can be selected as appropriate. The grooves 3 have a substantially uniform width in the direction along the depth of the grooves 3.

[0034] The width x2 (mm) and depth y2 (mm) of groove 3 satisfy requirements (b1) through (b3) below. For details, please refer to Figures 8 and 9 and see Test Example 2. (b1) In 0.05 ≤ x² < 0.2, y² > 5x² + 0.4 (b2) In the case of 0.2 ≤ x² < 0.5, y² > 28.7x² - 4.3 (b3) For 0.5 ≤ x², y² > 6x² + 7

[0035] The upper limit of the depth y2 (mm) of the groove 3 relative to its width x2 (mm) depends, for example, on the width limit of the tool or the size limit of the compacted molded body during the manufacturing process.

[0036] The sintered member 1 may have both a hole 2 and a groove 3, although these are not shown in the illustration.

[0037] [Method for manufacturing sintered members] The method for manufacturing a sintered member according to the embodiment comprises a step A for preparing raw material powder, a step B for producing a compacted body, a step C for producing a processed body, and a step D for sintering the processed body. One of the features of the method for manufacturing a sintered member is that a specific raw material powder is prepared in step A, and at least one of a specific hole portion and groove portion is formed in step C. The method for manufacturing a sintered member according to the embodiment manufactures the sintered member 1 described above.

[0038] [Process A: Preparation of raw material powder] In process A, a raw material powder containing metal powder and a lubricant is prepared. The raw material powder does not contain an organic binder. The metal powder is, for example, an iron-based powder or a non-ferrous powder.

[0039] (Iron-based powder) The iron-based powder is one type of powder selected from the group consisting of pure iron powder, ferric alloy powder, first mixed powder, second mixed powder, third mixed powder, and fourth mixed powder. The pure iron constituting the pure iron powder has a purity of 99% or higher, as described above. The types of ferric alloys constituting the ferric alloy powder are the iron alloys described above. The first mixed powder consists of pure iron powder and alloying element powder. The alloying element powder is the powder of the elements that produce the iron alloy described above when process D is carried out. The alloying elements are the additive elements to the iron alloy described above. If the sintered member 1 to be manufactured consists of an iron alloy containing multiple types of additive elements, the alloying element powder contains powders of multiple types of additive elements. The second mixed powder consists of ferric alloy powder and carbon powder. An example of a ferric alloy constituting the ferric alloy powder is an Fe-Cu alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Mo alloy, Fe-Cr alloy, Fe-Ni alloy, or Fe-Mo-Mn-Cr alloy. The third mixed powder consists of pure iron powder, the powder of the alloying element mentioned above, and ferric alloy powder. The fourth mixed powder consists of pure iron powder, the powder of the alloying element mentioned above, ferric alloy powder, and carbon powder.

[0040] (Non-ferrous powder) Non-ferrous powders include copper powder, copper alloy powder, aluminum powder, or aluminum alloy powder.

[0041] (Lubricant) The lubricant is one that spreads between multiple particles due to the processing heat generated when the raw material powder is pressurized in step B. Such a lubricant has a melting point of 150°C or less. The melting point of the lubricant may be further 110°C or less, and especially 85°C or less. The melting point of the lubricant is, for example, 50°C or higher. That is, the melting point of the lubricant may be 50°C or more and 150°C or less, further 55°C or more and 110°C or less, and especially 60°C or more and 85°C or less. Specific examples of lubricants are stearic acid, erucic acid amide, or stearic acid amide. These lubricants readily spread over a wide area between multiple particles due to the processing heat generated in step B.

[0042] The proportion of lubricant contained in the raw material powder is, for example, 0.025% by mass or more and 0.2% by mass or less. If the above proportion is 0.025% by mass or more, the lubricant is easily spread over a wide area between multiple particles due to the heat generated during processing in step B. Therefore, it is easy to form at least one of holes and grooves in step C. In particular, it is easy to form at least one of multiple holes and multiple grooves using the same tool. If the above proportion is 0.2% by mass or less, a dense compacted molded body is easily produced in step B. Furthermore, volume shrinkage due to the disappearance of lubricant when the processed body is sintered in step D can be suppressed, making it easy to manufacture sintered parts with high dimensional accuracy and high density. The above proportion may be further 0.04% by mass or more and 0.18% by mass or less. The above proportion is the value when the total raw material powder is 100% by mass.

[0043] [Process B: Production of compacted powder bodies] In process B, the raw material powder is pressurized to produce a compacted body having a relative density of 95% or more. The relative density may be further 97% or more, and especially 98% or more. The relative density of the compacted body is determined by [(actual density of the compacted body / true density of the compacted body) × 100]. The significance of the actual density of the compacted body is the same as that of the actual sintered member described above. The significance of the true density of the compacted body is the same as that of the true density of the sintered member described above. The shape of the compacted body can be selected as appropriate and is not particularly limited. The shape of the compacted body may be, for example, columnar or cylindrical. The compacted body is produced using an appropriate mold capable of forming it into the above shape.

[0044] The molding pressure is set such that the relative density of the molded powder compact is 95% or higher, and that enough heat is generated to spread the lubricant between the particles. In other words, in this process, the lubricant spreads due to the heat generated during molding. The mold is not heated by a heater to spread the lubricant. The molding pressure is, for example, 1560 MPa or higher. The higher the molding pressure, the higher the relative density of the powder compact produced. The molding pressure may be further 1660 MPa or higher, 1760 MPa or higher, and especially 1860 MPa or 1960 MPa or higher. There is no particular upper limit to the molding pressure.

[0045] [Process C: Fabrication of the processed body] In process C, a workpiece having at least one of a hole and a groove is produced by cutting the compacted molded body, which involves at least one of two cutting processes: hole drilling and groove drilling. The relationship between the diameter x1 and depth y1 of the formed hole is as described above. The relationship between the width x2 and depth y2 of the formed groove is as described above. Since a lubricant is spread between the particles of the compacted molded body, at least one of the holes and grooves that satisfy the above range can be formed. An example of a tool for forming a hole is a drill. Hole drilling may be performed under either internal or external lubrication wet conditions, depending on the diameter of the drill. An example of a tool for forming a groove is a dicing blade, a metal saw, or a grooving tool.

[0046] [Process D: Sintering of the processed body] In process D, the workpiece is sintered. The sintered member 1 is manufactured by sintering the workpiece. The workpiece shrinks due to sintering. The relative density of the workpiece is the same as the relative density of the compacted molded body. That is, the relative density of the workpiece is high. Therefore, the amount of shrinkage of the workpiece due to sintering is very small. Thus, the relative density of the sintered member 1 is greater than or equal to the relative density of the workpiece. That is, the relative density of the sintered member 1 is 95% or more. The size of the holes 2 and grooves 3 of the sintered member 1 substantially maintains the size of the holes and grooves of the workpiece. The sintering conditions can be appropriately selected according to the composition of the raw material powder. The sintering temperature is, for example, 1100°C to 1400°C, and may be further 1200°C to 1300°C. The sintering time is, for example, 15 minutes to 150 minutes, and may be further 20 minutes to 60 minutes. Known conditions can be applied to the sintering conditions.

[0047] [Other processes] A method for manufacturing a sintered member may include at least one step α of heat-treating the sintered member 1 and a step β of finishing the sintered member 1.

[0048] (Step α: Heat treatment of sintered material) In step α, the sintered member 1 is subjected to carburizing, quenching, and tempering. Step α easily improves the mechanical properties of the sintered member 1, particularly its hardness and toughness.

[0049] (Process β: Finishing of sintered material) In process β, the surface roughness of the sintered member 1 is reduced, and the dimensions of the sintered member 1 are adjusted to the design dimensions. One example of a finishing process is polishing the surface of the sintered member 1.

[0050] 《Example Test 1》 In Test Example 1, a sintered member having a hole was manufactured, and the relationship between the hole diameter x1 and depth y1 was evaluated.

[0051] [Samples No. 1 to No. 7] The sintered members of Sample No. 1 to Sample No. 7 were manufactured by performing steps A to D described above, in the same manner as the manufacturing method for sintered members in the embodiment described above.

[0052] [Process A] In process A, a raw material powder containing stainless steel powder and a lubricant was prepared. The composition of the stainless steel powder was 16% by mass of Cr and 12% by mass of Ni, with the remainder being Fe and unavoidable impurities. The lubricant was stearic acid. The melting point of stearic acid is 69.3°C. The proportion of lubricant in the raw material powder was 0.1% by mass.

[0053] [Process B] In process B, the above raw material powder was pressurized to produce a compacted powder body. The molding pressure was 1960 MPa.

[0055] [Process C] In process C, a processed body with a hole was produced by drilling a hole in the compacted powder body. The diameter x1 of the hole formed in samples No. 1 to No. 7 was 0.05 mm, 0.08 mm, 0.1 mm, 0.3 mm, 0.8 mm, 1.5 mm, and 2.0 mm, respectively.

[0056] The diameter of the hole (x1) was varied by changing the diameter of the drill. The hole machining was performed using MQL (Minimum Quantity Lubrication), which involves supplying a very small amount of cutting fluid along with a large amount of compressed gas during the machining process. When forming holes with diameters of 0.05 mm, 0.08 mm, 0.1 mm, 0.3 mm, or 0.8 mm, an external lubrication method was used for supplying the cutting fluid. When forming holes with diameters of 1.5 mm or 2.0 mm, an internal lubrication method was used for supplying the cutting fluid.

[0057] The processing conditions for each sample are as shown in Table 1. The holes in each sample were formed by step processing. Step processing is a process in which a hole is formed by repeatedly moving the drill forward and backward alternately. The step width in Table 1 refers to the depth of the hole drilled by one forward movement of the drill. For example, a step width of 2 mm in Table 1 means that the following procedure is followed: The drill is advanced and the compact is processed by the drill until the tip of the drill reaches a point 2 mm from the surface of the compact along the depth. The drill is then moved backward until the tip of the drill reaches the surface of the compact from the bottom of the hole, or until it reaches behind the surface of the compact from the bottom of the hole. Next, the drill is advanced and the compact is processed by the drill until the tip of the drill reaches a point 2 mm from the bottom of the hole along the depth. Next, the drill is moved backward until the tip of the drill reaches the surface of the compact from the bottom of the hole, or until it reaches behind the surface of the compact from the bottom of the hole. In this way, the forward and backward movement of the drill is repeated alternately. The number of steps refers to the number of times the drill moves forward and backward to reach a depth of y1. That is, if the step width is 2mm and the depth y1 is 70mm, the number of steps is 70 divided by 2, which is 35 steps. The values ​​shown in the column showing the relationship between diameter x1 and step width were calculated by dividing diameter x1 by the step width. The values ​​shown in the column showing the relationship between diameter x1 and feed rate were calculated by dividing the feed rate by diameter x1.

[0058] [Table 1]

[0059] Figures 5 to 7 show graphs illustrating the relationship between the hole diameter x1 and depth y1 in samples No. 1 to No. 7. Figure 6 is an enlarged graph of region A in Figure 5. Figure 7 is an enlarged graph of region B in Figure 6. The horizontal axis of the graphs in Figures 5 to 7 represents the hole diameter x1 (mm). The vertical axis of the graphs in Figures 5 to 7 represents the hole depth y1 (mm). The results for samples No. 1 to No. 7 are indicated by circles in the graphs in Figures 5 to 7.

[0060] In sample No. 1, a hole with a diameter x1 of 0.05 mm and a depth y1 of 0.4 mm was formed. In sample No. 2, a hole with a diameter x1 of 0.08 mm and a depth y1 of 0.8 mm was formed. In sample No. 3, a hole with a diameter x1 of 0.1 mm and a depth y1 of 3.3 mm was formed. In sample No. 4, a hole with a diameter x1 of 0.3 mm and a depth y1 of 6.0 mm was formed. In sample No. 5, a hole with a diameter x1 of 0.8 mm and a depth y1 of 15.0 mm was formed. In sample No. 6, a hole with a diameter x1 of 1.5 mm and a depth y1 of 50.0 mm was formed. In sample No. 7, a hole with a diameter x1 of 2.0 mm and a depth y1 of 70.0 mm was formed. In each sample, it was possible to form 20 of the above-mentioned holes in succession.

[0061] [Process D] In process D, a workpiece with a hole was heated to remove the lubricant, and the lubricant-free workpiece was sintered to produce a sintered member. The lubricant was removed from the workpiece by raising the temperature between 100°C and 250°C. The lubricant-free workpiece was held at 1100°C for 60 minutes. The sintering atmosphere was a vacuum atmosphere.

[0062] The relative density of the fabricated sintered member was 96.2%. The relative density of the compacted body was determined as described above by [(actual density of sintered member / true density of sintered member) × 100]. In each sample, the diameter x1 and depth y1 of the hole in the fabricated sintered member were substantially the same as the diameter x1 and depth y1 of the hole in the processed body.

[0063] [Samples No. 101 to No. 108] Sintered members No. 101 to No. 107 were manufactured in the same manner as samples No. 1 to No. 7, except that no lubricant was used in step A. Sintered member No. 108 was manufactured in the same manner as sample No. 107, except that the diameter x1 of the hole formed in step C was 3.0 mm.

[0064] The graphs in Figures 5 to 7 also show the relationship between the diameter x1 and depth y1 of the hole in samples No. 101 to No. 108. In the graphs in Figures 5 to 7, the results for samples No. 101 to No. 108 are indicated by triangles.

[0065] The diameter x1 of the hole in sample No. 101 was 0.05 mm, and the limit of the hole depth y1 was 0.35 mm. The diameter x1 of the hole in sample No. 102 was 0.08 mm, and the limit of the hole depth y1 was 0.43 mm. The diameter x1 of the hole in sample No. 103 was 0.1 mm, and the limit of the hole depth y1 was 1.0 mm. The diameter x1 of the hole in sample No. 104 was 0.3 mm, and the limit of the hole depth y1 was 3.0 mm. The diameter x1 of the hole in sample No. 105 was 0.8 mm, and the limit of the hole depth y1 was 7.0 mm. The diameter x1 of the hole in sample No. 106 was 1.5 mm, and the limit of the hole depth y1 was 30.0 mm. The diameter x1 of the hole in sample No. 107 was 2.0 mm, and the limit of the hole depth y1 was 40.0 mm. The diameter x1 of the hole in sample No. 108 was 3.0 mm, and the limit of the hole depth y1 was 50.0 mm. The limit of depth y1 referred to here is the maximum depth to which the drill can machine a diameter x1 without breaking.

[0066] 〔evaluation〕 We compare samples No. 1 to No. 7 and samples No. 101 to No. 107 that have the same hole diameter x1. As shown in Figures 5 to 7, for any diameter x1, the depth y1 of samples No. 1 to No. 7 is greater than the depth y1 of samples No. 101 to No. 107.

[0067] The straight line L1 connecting the points of sample No. 101 and sample No. 102, as shown in Figure 7, is given by y1 = 2.67x1 + 0.217. The values ​​for the slope and intercept have been rounded. The straight line L2 connecting the point of sample No. 102 and the point of sample No. 103 shown in Figure 6 is y1 = 28.5x1 - 1.85. The straight line L3 connecting the point of sample No. 103 shown in Figure 6 and the point of sample No. 104 shown in Figure 5 has the equation y1 = 10x1. The straight line L4 connecting the point of sample No. 104 and the point of sample No. 105 shown in Figure 5 is y1 = 8x1 + 0.6. The straight line L5 connecting the point of sample No. 105 and the point of sample No. 106, as shown in Figure 5, has the equation y1 = 32.9x1 - 19.3. The values ​​for the slope and intercept have been rounded. The straight line L6 connecting the point of sample No. 106 and the point of sample No. 107 shown in Figure 5 has the equation y1 = 20x1. The straight line L7 connecting the point of sample No. 107 and the point of sample No. 108 shown in Figure 5 is y1 = 10x1 + 20.

[0068] A sintered member having a hole, manufactured using raw material powder containing a lubricant with a melting point of 150°C or less, satisfies the following requirements (a1) to (a7). (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) In the case of 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) In 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20

[0069] The straight line L8 connecting the points of sample No. 1 and sample No. 2, as shown in Figure 7, is given by y1 = 13.3x1 + 0.267. The values ​​for the slope and intercept have been rounded. The straight line L9 connecting the points of sample No. 2 and sample No. 3, as shown in Figure 6, is given by y1 = 125x1 - 9.2. The values ​​for the slope and intercept have been rounded. The straight line L10 connecting the point of sample No. 3 shown in Figure 6 and the point of sample No. 4 shown in Figure 5 is y1 = 13.5x1 + 1.95. The straight line L11 connecting the point of sample No. 4 and the point of sample No. 5 shown in Figure 5 is y1 = 18x1 + 0.6. The straight line L12 connecting the point of sample No. 5 and the point of sample No. 6 shown in Figure 5 is y1 = 50x1 - 25. The straight line L13 connecting the point of sample No. 6 and the point of sample No. 7 shown in Figure 5 is y1 = 40x1 - 10. The line L14, which passes through sample No. 7 shown in Figure 5 and is parallel to line L7, has the equation y1 = 10x1 + 50.

[0070] A sintered member having a hole, manufactured using raw material powder containing a lubricant with a melting point of 150°C or less, can be seen to satisfy the following requirements (a51) and (a56). (a51) In the case of 0.05≦x1<0.08, y1=13.3x1+0.267 (a52) In the case of 0.08 ≤ x1 < 0.1, y1 = 125x1 - 9.2 (a53) In the case of 0.1 ≤ x1 < 0.3, y1 = 13.5x1 + 1.95 (a54) In the case of 0.3 ≤ x1 < 0.8, y1 = 18x1 + 0.6 (a55) In the case of 0.8 ≤ x1 < 1.5, y1 = 50x1 - 25 (a56) In 1.5 ≤ x1 < 2.0, y1 = 40x1 - 10 (a57) For 2.0 ≤ x1, y1 = 10x1 + 50

[0071] 《Example Test 2》 In Test Example 2, a sintered member having a groove was manufactured, and the relationship between the groove width x2 and depth y2 was evaluated.

[0072] [Samples No. 21 to No. 25] The sintered members of Samples No. 21 to No. 25 were manufactured in the same manner as Sample No. 1, except that grooves were created in the compacted molded body in step C to produce a processed body with grooves.

[0073] [Process C] The groove widths x2 formed in samples No. 21 to No. 25 were 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, and 0.5 mm, respectively. Grooves with a width x2 of 0.05 mm or 0.1 mm were formed using a dicing blade. Grooves with a width x2 of 0.2 mm, 0.3 mm, and 0.5 mm were formed using a metal saw.

[0074] Figures 8 and 9 show graphs illustrating the relationship between groove width x² and groove depth y² in samples No. 21 to No. 25. Figure 9 is an enlarged view of region C in Figure 8. The horizontal axis of the graphs in Figures 8 and 9 represents groove width x² (mm). The vertical axis of the graphs in Figures 8 and 9 represents groove depth y² (mm). The results for samples No. 21 to No. 25 are indicated by circles in the graphs in Figures 8 and 9.

[0075] In sample No. 21, a groove with a width x² of 0.05 mm and a depth y² of 0.7 mm was formed. In sample No. 22, a groove with a width x² of 0.1 mm and a depth y² of 1.0 mm was formed. In sample No. 23, a groove with a width x² of 0.2 mm and a depth y² of 1.6 mm was formed. In sample No. 24, a groove with a width x² of 0.3 mm and a depth y² of 9.0 mm was formed. In sample No. 25, a groove with a width x² of 0.5 mm and a depth y² of 19.0 mm was formed.

[0076] [Samples No. 201 to No. 207] Sintered members No. 201 to No. 205 were manufactured in the same manner as samples No. 21 to No. 25, except that no lubricant was used in process A. Sintered members No. 206 and No. 207 were manufactured in the same manner as sample No. 205, except that the width x2 of the groove formed in process C was 1.5 mm and 3.0 mm, respectively. The grooves with a width x2 of 1.5 mm or 3.0 mm were formed using a grooving tool.

[0077] The graphs in Figures 8 and 9 also show the relationship between the width x2 and depth y2 of the groove in samples No. 201 to No. 207. In the graphs in Figures 8 and 9, the results for samples No. 201 to No. 207 are indicated by triangles.

[0078] The groove width x2 of sample No. 201 was 0.05 mm, and the limit of the groove depth y2 was 0.65 mm. The groove width x² of sample No. 202 was 0.1 mm, and the limit of the groove depth y² was 0.9 mm. The groove width x² of sample No. 203 was 0.2 mm, and the limit of the groove depth y² was 1.4 mm. The groove width x² of sample No. 204 was 0.3 mm, and the limit of the groove depth y² was 3.0 mm. The groove width x2 of sample No. 205 was 0.5 mm, and the limit of the groove depth y2 was 10.0 mm. The groove width x2 of sample No. 206 was 1.5 mm, and the limit of the groove depth y2 was 15.0 mm. The groove width x2 of sample No. 207 was 3.0 mm, and the limit of the groove depth y2 was 25.0 mm. The limit of depth y2 referred to here is the maximum depth to which the tool can machine a width of x2 without breaking.

[0079] 〔evaluation〕 We compare samples No. 21 to No. 25 and samples No. 201 to No. 205, where the groove width x2 is the same. As shown in Figures 8 and 9, for any width x2, the depth y2 of samples No. 21 to No. 25 is greater than the depth y2 of samples No. 201 to No. 205.

[0080] The straight line L21 connecting the point of sample No. 201 and the point of sample No. 203 shown in Figure 9 is y² = 5x² + 0.4. The straight line L222 connecting the point of sample No. 203 shown in Figure 9 and the point of sample No. 205 shown in Figure 8 has the equation y² = 28.7x² - 4.3. The values ​​for the slope and intercept have been rounded. The straight line L23 connecting the point of sample No. 205 and the point of sample No. 207 shown in Figure 8 is y² = 6x² + 7.

[0081] A sintered member having grooves, manufactured using raw material powder containing a lubricant with a melting point of 150°C or less, satisfies the following requirements (b1) to (b3). (b1) In 0.05 ≤ x² < 0.2, y² > 5x² + 0.4 (b2) In the case of 0.2 ≤ x² < 0.5, y² > 28.7x² - 4.3 (b3) For 0.5 ≤ x², y² > 6x² + 7

[0082] The straight line L24 connecting the points of sample No. 21, sample No. 22, and sample No. 23 shown in Figure 9 is given by y² = 6x² + 0.4. The straight line L25 connecting the point of sample No. 23 shown in Figure 9 and the point of sample No. 24 shown in Figure 8 is y² = 74x² - 13.2. The straight line L26 connecting the point of sample No. 24 and the point of sample No. 25 shown in Figure 8 is y² = 50x² - 6. The line L27, which passes through sample No. 25 shown in Figure 8 and is parallel to line L23, has the equation y² = 6x² + 16.

[0083] A sintered member having grooves, manufactured using raw material powder containing a lubricant with a melting point of 150°C or less, satisfies requirements (b51) through (b54) below. (b51) In the case of 0.05≦x²<0.2, y²=6x²+0.4 (b52) In the case of 0.2 ≤ x² < 0.3, y² = 74x² - 13.2 (b53) In the case of 0.3 ≤ x² < 0.5, y² = 50x² - 6 (b54) For 0.5 ≤ x², y² = 6x² + 16

[0084] 《Test Example 3》 In Test Example 3, the number of holes that could be formed with the same drill was evaluated.

[0085] [Samples No. 31 to No. 34, Samples No. 301 to No. 304] The sintered members of Samples No. 31 to No. 34 were manufactured in the same manner as Sample No. 1, except that the diameter of the holes formed in the compacted molded body in process C was different. The sintered members of Samples No. 301 to No. 304 were manufactured in the same manner as Samples No. 31 to No. 34, except that a lubricant was not used in process A.

[0086] [Process C] The diameters of the holes formed in samples No. 31 to No. 34 are 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. The diameters of the holes formed in samples No. 301 to No. 304 are 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. When forming holes with a diameter of 0.4 mm or 0.6 mm, an external lubrication method was used for supplying the cutting fluid. When forming holes with a diameter of 0.8 mm or 1.0 mm, an internal lubrication method was used for supplying the cutting fluid. The depth of the holes formed in each sample was the same.

[0087] 〔evaluation〕 For each sample, the number of holes formed with the same drill was counted. Drilling was stopped when the number of formed holes reached 20. Numbers less than 20 indicate the number of holes formed without the drill breaking.

[0088] In sample No. 31, 20 holes with a diameter of 0.4 mm were successfully formed. In sample No. 32, 20 holes with a diameter of 0.6 mm were successfully formed. In sample No. 33, 20 holes with a diameter of 0.8 mm were successfully formed. In sample No. 34, 20 holes with a diameter of 1.0 mm were successfully formed.

[0089] In sample No. 301, zero holes with a diameter of 0.4 mm were formed. In sample No. 302, only one hole with a diameter of 0.6 mm was formed. In sample No. 303, eight holes with a diameter of 0.8 mm were successfully formed. In sample No. 304, 18 holes with a diameter of 1.0 mm were successfully formed.

[0090] Samples No. 31 to No. 34 and Samples No. 301 to No. 304 are compared if they have the same hole diameter. The smaller the diameter of the formed hole, the more likely it is that the raw material powder contains a lubricant with a melting point of 150°C or lower. below It was found that a larger number of holes could be formed compared to when the lubricant was not included.

[0091] 《Example Test 4》 In Test Example 4, a drill with a specially long flute length was prepared, and the upper limit of the hole depth was evaluated.

[0092] [Samples No. 41 to No. 44] The sintered components for each sample were manufactured in the same manner as for sample No. 1, except that the processing conditions in step C were as shown in Table 2.

[0093] [Process C] For sample No. 41, a drill with a flute length L of 30 mm, a diameter D of 0.6 mm, and an L / D ratio of 50 was used to form the hole. For sample No. 42, a drill with a flute length L of 40 mm, a diameter D of 0.8 mm, and an L / D ratio of 50 was used to form the hole. For sample No. 43, a drill with a flute length L of 40 mm, a diameter D of 1.0 mm, and an L / D ratio of 40 was used to form the hole. For sample No. 44, a drill with a flute length L of 50 mm, a diameter D of 1.0 mm, and an L / D ratio of 50 was used to form the hole. In the graph in Figure 5, the results for samples No. 41 to No. 44 are indicated by circles.

[0094] [Table 2]

[0095] 〔evaluation〕 In each sample, 320 holes were formed consecutively using the same drill. No drill breakage or other machining problems occurred during the hole formation process. From these results, it can be inferred that the upper limit of the hole depth y1 is determined by the constraint of whether or not a drill can be obtained as a tool. At least within the range demonstrated, it was confirmed that holes with y1 / x1 ≥ 50 can be obtained. From these results, it is thought that if a drill can be obtained, holes with y1 / x1 = 60, and even y1 / x1 = 80, and especially y1 / x1 = 100 can be formed.

[0096] The straight line L40 connecting the points of sample No. 41, sample No. 42, and sample No. 44 shown in Figure 5 is y1 = 50x1. Combining the results of Test Example 1 and Test Example 4, when the upper limit is set to y1 / x1 = 50, the following results are obtained. (a3) In 0.1 ≤ x1 < 0.3, 50x1 ≥ y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, 50x1 ≥ y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, 50x1 ≥ y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, 50x1 ≥ y1 > 20x1

[0097] Combining the results of Test Example 1 and Test Example 4, if the upper limit is set to y1 / x1 = 80, the result is as follows. (a3) In 0.1 ≤ x1 < 0.3, 80x1 ≥ y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, 80x1 ≥ y1 > 8x1 + 0.6 (a5) In the case of 0.8 ≤ x1 < 1.5, 80x1 ≥ y1 > 32.9x1 - 19.3 (a6) In 1.5 ≤ x1 < 2.0, 80x1 ≥ y1 > 20x1

[0098] The following was found from the results of Test Example 1 and Test Example 4. Holes with a depth y1 that is large relative to their diameter x1 are easily formed by step machining. The upper limit on the number of steps should not be particularly restricted; it should be set to a number that does not make the processing time excessively long. The step size should be smaller as the diameter x1 decreases. For example, the step size should be less than or equal to the diameter x1. The step size may also be less than or equal to half the diameter x1, or even less than or equal to one-fifth the diameter x1. The feed rate should be no more than 250 times the diameter x 1.

[0099] The present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims as shown, and equivalents thereof.

[0100] In relation to the embodiments of the present invention described above, the following further notes are disclosed.

[0101] [Note 1] A sintered member made of metal, The relative density is 95% or higher. The hole has a diameter x1 (mm) and a depth y1 (mm) that satisfy the following requirements (α1) to (α4). Sintered component. (α1) In the case of 0.1 ≤ x1 < 0.3, 50x1 ≥ y1 ≥ 10x1 + 2 (α2) In the case of 0.3 ≤ x1 < 0.8, 50x1 ≥ y1 ≥ 20x1 - 1 (α3) In the case of 0.8 ≤ x1 < 1.5, 50x1 ≥ y1 ≥ 50x1 - 25 (α4) In the case of 1.5≦x1<2.0, 50x1≧y1≧40x1-10

[0102] The sintered member described in Appendix 1 has a hole that is deep relative to its diameter. [Explanation of Symbols]

[0103] 1. Sintered member 2 Hole 3 grooves x1 diameter y1 depth x2 width y2 depth A, B, C area L1, L2, L3, L4, L5, L6, L7 straight line L8, L9, L10, L11, L12, L13, L14 Straight line L21, L22, L23 straight line L24, L25, L26, L27 straight line

Claims

1. A sintered member made of pure iron, iron alloy, copper, copper alloy, aluminum, or aluminum alloy, The relative density is 95% or higher. It has at least one hole portion which is a drilled hole having a uniform diameter in the direction along the depth, The at least one hole has a diameter x1 (mm) and a depth y1 (mm) that satisfy the following requirements (a1) to (a7): Sintered component. (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) Where 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) When 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) When 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20

2. The sintered member according to claim 1, wherein the iron alloy is stainless steel.

3. A sintered member according to claim 1 or claim 2, wherein the relative density is 97% or more.

4. A process of preparing raw material powders comprising powders made of pure iron, iron alloys, copper, copper alloys, aluminum, or aluminum alloys, and a lubricant, A step of pressurizing the raw material powder to produce a compacted molded body having a relative density of 95% or more, A process to produce a processed body having at least one hole having a uniform diameter in the direction along the depth, where the diameter x1 (mm) and depth y1 (mm) satisfy the following requirements (a1) to (a7), by drilling holes in the powder compacted body, The process includes a step of sintering the processed body, The proportion of the lubricant contained in the raw material powder is 0.025% by mass or more and 0.2% by mass or less. The melting point of the lubricant is 150°C or lower. The aforementioned hole machining is performed as follows: This is a step machining process in which the forward movement of the drill and the backward movement of the drill are repeated alternately to form the at least one hole portion. The step width (mm), which is the depth of the hole drilled by one forward movement of the drill, is set to be 1 times the diameter x 1 or less, and the feed rate (mm / min) is set to be 250 times the diameter x 1 or less. A method for manufacturing sintered components. (a1) In 0.05 ≤ x1 < 0.08, y1 > 2.67x1 + 0.217 (a2) Where 0.08 ≤ x1 < 0.1, y1 > 28.5x1 - 1.85 (a3) When 0.1 ≤ x1 < 0.3, y1 > 10x1 (a4) In 0.3 ≤ x1 < 0.8, y1 > 8x1 + 0.6 (a5) In 0.8 ≤ x1 < 1.5, y1 > 32.9x1 - 19.3 (a6) When 1.5 ≤ x1 < 2.0, y1 > 20x1 (a7) For 2.0 ≤ x1, y1 > 10x1 + 20

5. The method for manufacturing a sintered member according to claim 4, wherein the lubricant is stearic acid, erucic acid amide, or stearic acid amide.

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