SINTERED MEMBER AND METHOD FOR PRODUCING SINTERED MEMBER
US20250312848A1
2025-10-09
18/859,202
2023-04-24
Smart Summary: A sintered member is made from metal and is very dense, with a density of 95% or higher. It can have special features like holes or grooves that meet certain size requirements. The holes have specific measurements for their diameter and depth. Similarly, the grooves also have defined widths and depths. This design helps improve the performance and functionality of the metal piece. π TL;DR
Abstract:
A sintered member composed of a metal, wherein the sintered member has a relative density of 95% or more and has at least one of a hole for which the diameter x1 and depth y1 satisfy specific requirements and a groove for which the width x2 and depth y2 satisfy specific requirements.
Inventors:
- Shigeki EGASHIRA 5 π―π΅ Osaka-shi, Osaka, Japan
- Takayuki TASHIRO 4 π―π΅ Osaka-shi, Osaka, Japan
- Tomoyuki ISHIMINE 9 π―π΅ Osaka-shi, Osaka, Japan
- Kazunari SHIMAUCHI 6 π―π΅ Osaka-shi, Osaka, Japan
Assignee:
- Sumitomo Electric Industries, Ltd. 2,632 π―π΅ Osaka-shi, Osaka, Japan
- SUMITOMO ELECTRIC SINTERED ALLOY, LTD. 47 π―π΅ Takahashi-shi, Okayama, Japan
Applicant:
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Classification:
B22F5/10 » CPC main
Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
B22F2301/35 » CPC further
Metallic composition of the powder or its coating Iron
B22F2998/10 » CPC further
Supplementary information concerning processes or compositions relating to powder metallurgy Processes characterised by the sequence of their steps
B22F3/16 » CPC further
Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces; Both compacting and sintering in successive or repeated steps
Description
TECHNICAL FIELD
The present disclosure relates to a sintered member and a method of manufacturing a sintered member.
The present application claims priority from Japanese Patent Application No. 2022-071901 filed on Apr. 25, 2022, the entire contents of which are incorporated herein by reference.
BACKGROUND ART
A method of manufacturing a sintered member in PTL 1 includes the step of subjecting a raw material powder to press-forming to produce a green compact, the step of forming a hole in the green compact, and the step of sintering the green compact having the hole formed therein. The raw material powder contains iron powder, copper powder, carbon powder, and ethylenebisstearamide.
CITATION LIST
Patent Literature
- PTL 1: Japanese Unexamined Patent Application Publication No. 2019-14971
SUMMARY OF INVENTION
The sintered member of the present disclosure is
-
- a sintered member composed of a metal,
- wherein the sintered member has a relative density of 95% or more,
- wherein the sintered member has at least one of a hole having a diameter x1 (mm) and a depth y1 (mm) and a groove having a width x2 (mm) and a depth y2 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below, the width x2 and the depth y2 satisfying requirements (b1) to (b3) below:
when 0.05 β€ x β’ 1 < 0.08 , y β’ 1 > 2.67 x β’ 1 + 0.217 ; ( a1 ) when 0.08 β€ x β’ 1 < 0.1 , y β’ 1 > 28.5 x β’ 1 - 1.85 ; ( a2 ) when 0.1 β€ x β’ 1 < 0.3 , y β’ 1 > 10 β’ x β’ 1 ; ( a3 ) when 0.3 β€ x β’ 1 < 0.8 , y β’ 1 > 8 β’ x β’ 1 + 0.6 ; ( a4 ) when 0.8 β€ x β’ 1 < 1.5 , y β’ 1 > 32.9 x β’ 1 - 19.3 ; ( a5 ) when 1.5 β€ x β’ 1 < 2. , y β’ 1 > 20 β’ x β’ 1 ; ( a6 ) when 2. β€ x β’ 1 , y β’ 1 > 10 β’ x β’ 1 + 20 ; ( a7 ) when 0.05 β€ x β’ 2 < 0.2 , y β’ 2 > 5 β’ x β’ 2 + 0.4 ; ( b1 ) when 0.2 β€ x β’ 2 < 0.5 , y β’ 2 > 28.7 x β’ 2 - 4.3 ; and ( b2 ) when 0.5 β€ x β’ 2 , y β’ 2 > 6 β’ x β’ 2 + 7. ( b3 )
The sintered member manufacturing method of the present disclosure includes:
-
- preparing a raw material powder containing a metal powder and a lubricant;
- pressing the raw material powder to produce a green compact having a relative density of 95% or more;
- subjecting the green compact to at least one cutting process selected from hole drilling and grooving to produce a workpiece having at least one of a hole having a diameter x1 (mm) and a depth y1 (mm) and a groove having a width x2 (mm) and a depth y2 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below, the width x2 and the depth y2 satisfying requirements (b1) to (b3) below; and
- sintering the workpiece,
- wherein the ratio of the lubricant contained in the raw material powder is 0.025% by mass to 0.2% by mass, and
- wherein the lubricant has a melting point of 150Β° C. or lower:
when 0.05 β€ x β’ 1 < 0.08 , y β’ 1 > 2.67 x β’ 1 + 0.217 ; ( a1 ) when 0.08 β€ x β’ 1 < 0.1 , y β’ 1 > 28.5 x β’ 1 - 1.85 ; ( a2 ) when 0.1 β€ x β’ 1 < 0.3 , y β’ 1 > 10 β’ x β’ 1 ; ( a3 ) when 0.3 β€ x β’ 1 < 0.8 , y β’ 1 > 8 β’ x β’ 1 + 0.6 ; ( a4 ) when 0.8 β€ x β’ 1 < 1.5 , y β’ 1 > 32.9 x β’ 1 - 19.3 ; ( a5 ) when 1.5 β€ x β’ 1 < 2. , y β’ 1 > 20 β’ x β’ 1 ; ( a6 ) when 2. β€ x β’ 1 , y β’ 1 > 10 β’ x β’ 1 + 20 ; ( a7 ) when 0.05 β€ x β’ 2 < 0.2 , y β’ 2 > 5 β’ x β’ 2 + 0.4 ; ( b1 ) when 0.2 β€ x β’ 2 < 0.5 , y β’ 2 > 28.7 x β’ 2 - 4.3 ; and ( b2 ) when 0.5 β€ x β’ 2 , y β’ 2 > 6 β’ x β’ 2 + 7. ( b3 )
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic perspective view illustrating a sintered member in an embodiment.
FIG. 2 is a cross-sectional view along line II-II in FIG. 1.
FIG. 3 is a partial cross-sectional view illustrating another example of the sintered member in the embodiment.
FIG. 4 is a cross-sectional view along line IV-IV in FIG. 3.
FIG. 5 is a graph showing the relation between the diameter and depth of holes in each of sintered members produced in Test Example 1.
FIG. 6 is an enlarged graph of region A in FIG. 5.
FIG. 7 is an enlarged graph of region B in FIG. 6.
FIG. 8 is a graph showing the relation between the width and depth of grooves in each of sintered members produced in Test Example 2.
FIG. 9 is an enlarged graph of region C in FIG. 8.
DETAILED DESCRIPTION
Problems to be Solved by Present Disclosure
There is a demand for manufacturing a sintered member having a hole with a large depth relative to its diameter or having a groove with a large depth relative to its width.
One object of the present disclosure is to provide a sintered member having a hole with a large depth relative to its diameter or having a groove with a large depth relative to its width. Another object of the present disclosure is to provide a method of manufacturing the sintered member.
Advantageous Effects of Present Disclosure
The sintered member of the present disclosure has a hole with a large depth relative to its diameter or has a groove with a large depth relative to its width. The sintered member manufacturing method of the present disclosure can manufacture the sintered member of the present disclosure.
Description of Embodiments of Present Disclosure
First, embodiments of the present disclosure will be enumerated and described.
-
- (1) One embodiment of the sintered member of the present disclosure is
- a sintered member composed of a metal,
- wherein the sintered member has a relative density of 95% or more,
- wherein the sintered member has at least one of a hole having a diameter x1 (mm) and a depth y1 (mm) and a groove having a width x2 (mm) and a depth y2 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below, the width x2 and the depth y2 satisfying requirements (b1) to (b3) below:
( a β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 ; ( a β’ β’ 2 ) when β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 ; ( a β’ β’ 3 ) when β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 ; ( a β’ β’ 4 ) when β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 ; ( a β’ β’ 5 ) when β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 ; ( a β’ β’ 6 ) when β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1 ; ( a β’ β’ 7 ) when β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20 ; ( b β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 ; ( b β’ β’ 2 ) when β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 ; and ( b β’ β’ 3 ) when β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
The sintered member has the hole with a large depth relative to its diameter or the groove with a large depth relative to its width.
-
- (2) In the sintered member according to (1),
- the metal may be pure iron or an iron alloy.
The sintered member composed of pure iron or an iron alloy has the hole with a large depth relative to its diameter or the groove with a large depth relative to its width.
-
- (3) In the sintered member according to (1),
- the metal may be stainless steel.
The sintered member composed of stainless steel has the hole with a large depth relative to its diameter or the groove with a large depth relative to its width.
-
- (4) A sintered member manufacturing method in an embodiment of the present disclosure includes:
- preparing a raw material powder containing a metal powder and a lubricant;
- pressing the raw material powder to produce a green compact having a relative density of 95% or more;
- subjecting the green compact to at least one cutting process selected from hole drilling and grooving to produce a workpiece having at least one of a hole having a diameter x1 (mm) and a depth y1 (mm) and a groove having a width x2 (mm) and a depth y2 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below, the width x2 and the depth y2 satisfying requirements (b1) to (b3) below; and
- sintering the workpiece,
- wherein the ratio of the lubricant contained in the raw material powder is 0.025% by mass to 0.2% by mass, and
- wherein the lubricant has a melting point of 150Β° C. or lower:
( a β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 ; ( a β’ β’ 2 ) when β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 ; ( a β’ β’ 3 ) when β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 ; ( a β’ β’ 4 ) when β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 ; ( a β’ β’ 5 ) when β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 ; ( a β’ β’ 6 ) when β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1 ; ( a β’ β’ 7 ) when β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20 ; ( b β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 ; ( b β’ β’ 2 ) when β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 ; and ( b β’ β’ 3 ) when β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
In the above sintered member manufacturing method, the raw material powder containing the lubricant having a melting point of 150Β° C. or lower is pressed, and this allows the lubricant to easily spread into spaces between the particles of the green compact produced. Since the lubricant has been spread into the spaces between the particles in the green compact, the hole can be formed by drilling the green compact, and the groove can be formed by grooving the green compact. The relative density of the green compact is the same as the relative density of the workpiece. Since the relative density of the green compact produced is 95% or more, the amount of shrinkage when the workpiece is sintered is very small. Therefore, the dimensions of the hole and the groove in the workpiece are maintained and are substantially the same as the dimensions of the hole and the groove in the sintered member. With the sintered member manufacturing method described above, a sintered member having a hole with a large depth relative to its diameter or having a groove with a large depth relative to its width can be produced.
-
- (5) In the sintered member manufacturing method according to (4),
- the lubricant may be stearic acid, erucic acid amide, or stearic acid amide.
By pressing the raw material powder, the lubricant can easily and widely spread into the spaces between the particles in the green compact.
Details of Embodiments of Present Disclosure
Embodiments of the present disclosure will be described based on the drawings. In the drawings, the same numerals denote components with the same names. The dimensions of members shown in the drawings are for the purpose of clarity of description, and these dimensions do not necessarily represent the actual dimensional relations.
Embodiments
[Sintered Member]
Referring to FIGS. 1 to 4, a sintered member 1 in an embodiment will be described. The sintered member 1 is composed of a metal. One feature of the sintered member 1 in the present embodiment is that the sintered member 1 has a high relative density and has at least one of a hole 2 having a specific size and a groove 3 having a specific size.
[Material]
The material of the sintered member 1 is a metal. The metal is, for example, pure iron, an iron alloy, or a nonferrous metal.
The pure iron is iron with a purity of 99% or more. Specifically, the pure iron is a material with an iron (Fe) content of 99% by mass or more.
The iron alloy is an alloy containing an additive element with the balance being iron (Fe) and unavoidable impurities. In the iron alloy, the content of Fe is highest. The additive element contained in the iron alloy is, for example, at least one element 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 the iron alloy include stainless steel, FeβC-based alloys, FeβCuβNiβMo-based alloys, FeβNiβMoβMn-based alloys, FeβP-based alloys, FeβCu-based alloys, FeβCuβC-based alloys, FeβCuβMo-based alloys. FeβNiβMoβCuβC-based alloys. FeβNiβCu-based alloys, FeβNiβMoβC-based alloys, FeβNiβCr-based alloys, FeβNiβMoβCr-based alloys, FeβCr-based alloys. FeβMoβCr-based alloys, FeβCrβC-based alloys, FeβNiβC-based alloys, and FeβMoβMnβCrβC-based alloys. Examples of the stainless steel include austinite stainless steel. Examples of the austenite stainless steel include SUS304 and SUS304L.
The nonferrous metal is, for example, copper, a copper alloy, aluminum, or an aluminum alloy.
The composition of the sintered member 1 can be checked by analyzing the composition by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry).
[Relative Density]
The relative density of the sintered member 1 is 95% or more. The sintered member 1 having a relative density of 95% or more has good mechanical properties such as strength. The relative density of the sintered member 1 may be 96% or more, particularly 97% or more. No particular limitation is imposed on the upper limit of the relative density of the sintered member 1, and the upper limit can be appropriately selected so long as the sintered member 1 can be manufactured. The relative density of the sintered member 1 may be, for example, 99.9% or lower. Specifically, the relative density of the sintered member 1 may be 95% to 99.9%, 96% to 99.9%, particularly 97% to 99.9%.
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. Specifically, the relative density of the sintered member 1 is determined as [(actual density of sintered member 1)/(true density of sintered member 1)Γ100]. The actual density of the sintered member 1 can be determined by immersing the sintered member 1 in oil to impregnate the sintered member 1 with the oil and computing [oil-impregnated density (mass of sintered member 1 before impregnation with oil)/(mass of sintered member 1 after impregnation with oil)]. The oil-impregnated density is defined as (mass of sintered member 1 after impregnation with oil/volume of sintered member 1 after impregnation with oil). Specifically, the actual density of the sintered member 1 can be determined as (mass of sintered member 1 before impregnation with oil/volume of sintered member 1 after impregnation with oil). The volume of the sintered member 1 after impregnation with the oil can be measured typically by a liquid displacement method. The true density of the sintered member 1 is a theoretical density determined from the composition of the sintered member 1 on the assumption that the sintered member 1 contains no voids.
[Hole]
The hole 2 is a through hole or a blind hole. The blind hole has a bottom. No particular limitation is imposed on the number of holes 2, and the number can be appropriately selected. When the number of holes 2 is two or more, the holes 2 may include both a through hole and a blind hole. The hole 2 has a substantially uniform diameter in a direction along the depth of the hole 2.
The diameter x1 (mm) and depth y1 (mm) of the hole 2 satisfy the following requirements (a1) to (a7). The details of the requirements will be described in Test Example 1 with reference to FIGS. 5 to 7.
( a β’ β’ 1 ) W β’ hen β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 . ( a β’ β’ 2 ) W β’ hen β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 . ( a β’ β’ 3 ) W β’ hen β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1. ( a β’ β’ 4 ) W β’ hen β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 . β’ ( a β’ β’ 5 ) W β’ hen β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 . β’ ( a β’ β’ 6 ) W β’ hen β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1. ( a β’ β’ 7 ) W β’ hen β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20.
The upper limit of the depth y1 (mm) of the hole 2 relative to the diameter x1 (mm) depends on, for example, the limit of the diameter of the tool and the limit of its length or the limit of the size of the green compact during its manufacturing process. For example, in a commonly used commercial drill used to form the hole 2, the ratio L/D of the flute length L (mm) of the drill to the diameter D (mm) of the drill is about 20 or less or about 30 or less. The limit of the ratio LD depends on the diameter D and the material of the tool but is said to be 40 or less or 50 or less, even for special drills used to drill particularly deep holes. For example, the upper limit of the depth y1 of the hole 2 relative to the diameter x1 is at least 50 times the diameter x1 in all the requirements (a1) to (a7). It is considered that the depth of the hole 2 formed by a method of manufacturing the sintered member in the present embodiment described later can be larger than the depth of a hole that can be formed using a drill with L/D=50, which is the manufacturing limit of the drill.
[Groove]
No particular limitation is imposed on the number of grooves 3, and the number of grooves 3 can be appropriately selected. The groove 3 has a substantially uniform width in a direction along the depth of the groove 3.
The width x2 (mm) and depth y2 (mm) of the groove 3 satisfy the following requirements (b1) to (b3). The details of the requirements will be described in Test Example 2 with reference to FIGS. 8 and 9.
( b β’ β’ 1 ) When β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 . ( b β’ β’ 2 ) When β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 . ( b β’ β’ 3 ) When β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
The upper limit of the depth y2 (mm) of the groove 3 relative to the width x2 (mm) depends on, for example, the limit of the width of the tool or the limit of the size of the green compact during its manufacturing process.
The sintered member 1 may have both the hole 2 and the groove 3, although their illustration is omitted.
[Method of Manufacturing Sintered Member]
A sintered member manufacturing method according to an embodiment includes: step A of preparing a raw material powder; step B of producing a green compact; step C of producing a workpiece; and step D of sintering the workpiece. One feature of the sintered member manufacturing method is that the specific raw material powder is prepared in step A and at least one of the specific hole and groove is formed in step C. With the sintered member manufacturing method according to the embodiment, the sintered member 1 described above is manufactured.
[Step A: Preparation of Raw Material Powder]
In step A, the raw material powder containing a metal powder and a lubricant is prepared. The raw material powder contains no organic binder. The metal powder is, for example, a ferrous powder or a nonferrous powder.
(Ferrous Powder)
The ferrous powder is one powder selected from the group consisting of a pure iron powder, a first iron alloy powder, a first powder mixture, a second powder mixture, a third powder mixture, and a fourth powder mixture. The pure iron included in the pure iron powder has a purity of 99% or more as described above. The first iron alloy included in the first iron alloy powder is the iron alloy described above. The first powder mixture is composed of the pure iron powder and an alloying element powder. The alloying element powder is a powder of an element used to produce the iron alloy in step D. The alloying element is an additive element of the above-described iron alloy. When the sintered member 1 manufactured is composed of an iron alloy containing a plurality of additive elements, the alloying element powder contains a plurality of additive element powders. The second powder mixture is composed of a second iron alloy powder and a carbon powder. Examples of the second iron alloy contained in the second iron alloy powder include FeβCu-based alloys, FeβNiβMoβCu-based alloys, FeβNiβMo-based alloys, FeβCr-based alloys, FeβNi-based alloys, and FeβMoβMnβCr-based alloys. The third powder mixture is composed of the pure iron powder, the alloying element powder, and the first iron alloy powder. The fourth powder mixture is composed of the pure iron powder, the alloying element powder, the second iron alloy powder, and a carbon powder.
(Nonferrous Powder)
The nonferrous powder is a copper powder, a copper alloy powder, an aluminum powder, or an aluminum alloy powder.
(Lubricant)
The lubricant spreads into the spaces between a plurality of particles under the processing heat generated when the raw material powder is pressed in step B. Such a lubricant has a melting point of 150Β° C. or lower. The melting point of the lubricant may be 110Β° C. or lower, particularly 85Β° C. or lower. The melting point of the lubricant is, for example, 50Β° C. or higher. Specifically, the melting point of the lubricant may be 50Β° C. to 150Β° C., 55Β° C. to 110Β° C., particularly 60Β° C. to 85Β° C. Specific examples of the lubricant include stearic acid, erucic acid amide, and stearic acid amide. These lubricants can easily and widely spread into the spaces between the plurality of particles under the processing heat in step B.
The content of the lubricant contained in the raw material powder is, for example, 0.025% by mass to 0.2% by mass. When the content is 0.025% by mass or more, the lubricant can easily and widely spread into the spaces between the plurality of particles under the processing heat in step B. Therefore, at least one of the hole and the groove can be easily formed in step C. In particular, a plurality of holes and/or a plurality of grooves can be easily formed using the same tool. When the above content is 0.2% by mass or lower, a dense green compact can be easily formed in step B. Moreover, volume shrinkage due to loss of the lubricant when the workpiece is sintered in step D can be reduced, and a high-density sintered member with high dimensional accuracy can be easily manufactured. The content may be 0.04% by mass to 0.18% by mass. The content is a value when the total amount of the raw material powder is set to 100% by mass.
[Step B. Production of Green Compact]
In step B, the raw material powder is pressed to produce a green compact having a relative density of 95% or more. The relative density may be 97% or more, particularly 98% or more. The relative density of the green compact is determined as [(actual density of green compact/true density of green compact)Γ100]. The meaning of the actual density of the green compact is the same as the meaning of the actual density of the sintered member described above. The meaning of the true density of the green compact is the same as the true density of the sintered member described above. No particular limitation is imposed on the shape of the green compact, and the shape can be appropriately selected. The shape of the green compact is, for example, columnar or tubular. The green compact is produced using an appropriate die that can be used to form any of the above shapes.
The molding pressure is set such that the green compact formed has a relative density of 95% or more and that heat allowing the lubricant to spread into the spaces between the particles is generated. Specifically, in this step, the processing heat during molding allows the lubricant to spread. To allow the lubricant to spread, the die is not heated by a heater. The molding pressure is, for example, 1560 MPa or more. The higher the molding pressure, the higher the relative density of the green compact produced. The molding pressure may be 1660 MPa or more, 1760 MPa or more, particularly 1860 MPa, and 1960 MPa or more. The upper limit of the molding pressure is not specifically set.
[Step C: Production of Workpiece]
In step C, the green compact is subjected to at least one cutting process selected from hole drilling and grooving, and a workpiece having at least one of a hole and a groove is thereby produced. The relations between the diameter x1 and depth y1 of the formed hole are within the ranges described above. The relations between the width x2 and depth y2 of the formed groove are within the ranges described above. Since the lubricant has been spread into the spaces between the particles of the green compact, at least one of the hole and groove satisfying the above ranges can be formed. A drill is one example of the tool used to form the hole. The drilling may be performed under wet conditions with internal or external lubrication, which depends on the diameter of the drill. Examples of the tool used to form the groove include dicing blades, metal saws, and grooving tools.
[Step D: Sintering of Workpiece]
In step D, the workpiece is sintered. By sintering the workpiece, the sintered member 1 is manufactured. As a result of the sintering, the workpiece shrinks. The relative density of the workpiece is the same as the relative density of the green compact. Specifically, the workpiece has a high relative density. Therefore, the amount of shrinkage of the workpiece due to sintering is very small. In this case, the relative density of the sintered member 1 is more than or equal to the relative density of the workpiece. Specifically, the relative density of the sintered member 1 is 95% or more. The dimensions of the hole and groove in the workpiece are maintained and are substantially the same as the dimensions of the hole 2 and the groove 3 in the sintered member 1. The sintering conditions can be appropriately selected according to the composition of the raw material powder. The sintering temperature is, for example, 1100Β° C. to 1400Β° C. and may be 1200Β° C. to 1300Β° C. The sintering time is, for example, 15 minutes to 150 minutes and may be 20 minutes to 60 minutes. Well-known sintering conditions may be applied.
[Other Steps]
The sintered member manufacturing method may further include at least one step selected from step Ξ± of subjecting the sintered member 1 to heat treatment and step Ξ² of subjecting the sintered member 1 to finishing processing.
(Step Ξ±: Heat Treatment of Sintered Member)
In step Ξ±, the sintered member 1 is subjected to carburizing and quenching and then to tempering. The mechanical properties, particularly hardness and toughness, of the sintered member 1 are likely to be improved through step Ξ±.
(Step Ξ²: Finishing Processing of Sintered Member)
In step Ξ², the surface roughness of the sintered member 1 is reduced, and the dimensions of the sintered member 1 are adjusted to its design dimensions. Examples of the finishing processing include surface polishing of the sintered member 1.
Test Example 1
In Test Example 1, sintered members having holes were manufactured, and the relation between the diameter x1 and depth y1 of the holes was evaluated.
[Samples Nos. 1 to 7]
Sintered member samples Nos. 1 to 7 were manufactured by performing steps A to D in the sintered member manufacturing method described above.
[Step A]
In step A, a raw material powder containing a 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 balance being Fe and unavoidable impurities. The lubricant was stearic acid. The melting point of stearic acid is 69.3Β° C. The content of the lubricant contained in the raw material powder was 0.1% by mass.
[Step B]
In step B, the raw material powder was pressed to produce green compacts. The molding pressure was 1960 MPa.
The relative density of each green compact produced was 99.5%. The relative density of the green compact was determined as [(actual density of green compact)/(true density of green compact)Γ100] as described above.
[Step C]
In step C, the green compacts were drilled to produce workpieces having holes. The diameters x1 of the holes formed in samples Nos. 1 to 7 were 0.05 mm, 0.08 mm, 0.1 mm, 0.3 mm, 0.8 mm, 1.5 mm, and 2.0 mm, respectively.
The holes having different diameters x1 were formed by using drills having different diameters. The drilling was MQL (Minimum Quantity Lubrication) processing in which the green compact was subjected to cutting processing while a trace amount of a cutting fluid was supplied along with a large amount of compressed gas. When holes with a diameter of 0.05 mm, 0.08 mm, 0.1 mm, 0.3 mm, or 0.8 mm were formed, the cutting fluid was supplied using an external lubrication method. When holes with a diameter of 1.5 mm or 2.0 mm were formed, the cutting fluid was supplied using an internal lubrication method.
The processing conditions for the samples are as shown in Table 1. The holes in the samples were formed by step feed drilling. The step feed drilling is a drilling process in which the drill is repeatedly advanced and retracted in an alternating manner to form a hole. The step width in Table 1 is the depth of the hole formed by one advance movement of the drill. When, for example, the step width in Table 1 is 2 mm, the following procedure is performed. The drill is advanced to drill the green compact until the forward end of the drill reaches a depth of 2 mm from the surface of the green compact. Then the drill is retracted from the bottom of the hole until the forward end of the drill reaches the surface of the green compact or a position rearward of the surface of the green compact. Next, the drill is advanced to drill the green compact until the forward end of the drill reaches a depth of 2 mm from the bottom of the hole. Next, the drill is retracted from the bottom of the hole until the forward end of the drill reaches the surface of the green compact or a position rearward of the surface of the green compact. The drill is repeatedly advanced and retracted in the alternating manner described above. The number of steps is the number of times the drill is repeatedly advanced and retracted until the drill reaches the depth y1. Specifically, when the step width is 2 mm and the depth y1 is 70 mm, the step number is a value obtained by dividing 70 by 2, i.e., 35. A value shown in the βRelation between diameter x1 and step widthβ column was determined by dividing the diameter x1 by the step width. A value shown in the βRelation between diameter x1 and feed speedβ column was determined by dividing the feed speed by the diameter x1.
| TABLE 1 | |||
| NUMBER | RELATION | ||
| OF | RELATION | BETWEEN |
| HOLE | STEPS | BETWEEN | DIAMETER |
| DIAMETER | DEPTH | NUMBER OF | FEED PER | FEED | STEP | NUMBER | DIAMETER | x1 AND | ||
| SAMPLE | x1 | y1 | REVOLUTIONS | REVOLUTION | SPEED | WIDTH | OF | x1 AND | FEED SPEED | |
| No. | mm | mm | y1/x1 | rpm | mm | mm/min | mm | TIMES | STEP WIDTH | /min |
| 1 | 0.05 | 0.4 | 8.0 | 15000 | 0.0008 | 12 | 0.01 | 40 | 5 | 240 |
| 2 | 0.08 | 0.8 | 10.0 | 12000 | 0.0008 | 9.6 | 0.01 | 80 | 8 | 120 |
| 3 | 0.1 | 3.3 | 33.0 | 12000 | 0.001 | 12 | 0.01 | 330 | 10 | 120 |
| 4 | 0.3 | 6.0 | 20.0 | 11000 | 0.002 | 22 | 0.03 | 200 | 10 | 73 |
| 5 | 0.8 | 15.0 | 18.8 | 7962 | 0.02 | 159 | 0.4 | 38 | 2 | 199 |
| 6 | 1.5 | 50.0 | 33.3 | 7430 | 0.05 | 372 | 1.5 | 34 | 1 | 248 |
| 7 | 2.0 | 70.0 | 35.0 | 7962 | 0.05 | 398 | 2 | 35 | 1 | 199 |
FIGS. 5 to 7 are graphs showing the relation between the diameter x1 and depth y1 of the holes in each of samples Nos. 1 to 7. FIG. 6 is an enlarged graph of region A in FIG. 5. FIG. 7 is an enlarged graph of region B in FIG. 6. The horizontal axis of each of the graphs in FIGS. 5 to 7 represents the diameter x1 (mm) of holes. The vertical axis of each of the graphs in FIGS. 5 to 7 represents the depth y1 (mm) of holes. In the graphs in FIGS. 5 to 7, the results for samples Nos. 1 to 7 are shown using circles.
In sample No. 1, holes with a diameter x1 of 0.05 mm and a depth y1 of 0.4 mm could be formed.
In sample No. 2, holes with a diameter x1 of 0.08 mm and a depth y1 of 0.8 mm could be formed.
In sample No. 3, holes with a diameter x1 of 0.1 mm and a depth y1 of 3.3 mm could be formed.
In sample No. 4, holes with a diameter x1 of 0.3 mm and a depth y1 of 6.0 mm could be formed.
In sample No. 5, holes with a diameter x1 of 0.8 mm and a depth y1 of 15.0 mm could be formed.
In sample No. 6, holes with a diameter x1 of 1.5 mm and a depth y1 of 50.0 mm could be formed.
In sample No. 7, holes with a diameter x1 of 2.0 mm and a depth y1 of 70.0 mm could be formed.
Twenty holes could be continuously formed in each sample.
[Step D]
In step D, each of the workpieces having the holes was heated to remove the lubricant, and the workpiece with the lubricant removed was sintered to produce a sintered member. By heating the workpiece to 100Β° C. to 250Β° C., the lubricant was removed from the workpiece. The workpiece with the lubricant removed was held at 1100Β° C. for 60 minutes. The sintering atmosphere was a vacuum atmosphere.
The relative density of each sintered member produced was 96.2%. The relative density of the green compact was determined as [(actual density of sintered member)/(true density of sintered member)Γ100] as described above. For each of the samples, the diameter x1 and depth y1 of the holes in the sintered member were substantially the same as the diameter x1 and depth y1 of the holes in the workpiece.
[Samples Nos. 101 to 108]
Sintered member samples Nos. 101 to 107 were manufactured using the same procedures as for samples Nos. 1 to 7, respectively, except that the lubricant was not used in step A. Sintered member sample No. 108 was manufactured using the same procedure as for sample No. 107 except that the diameter x1 of the holes formed in step C was changed to 3.0 mm.
The graphs in FIGS. 5 to 7 also show the relation between the diameter x1 and depth y1 of the holes in each of samples Nos. 101 to 108. In the graphs in FIGS. 5 to 7, the results for samples Nos. 101 to 108 are shown using triangles.
In sample No. 101, the diameter x1 of the holes was 0.05 mm, and the limit of the depth y1 of the holes was 0.35 mm.
In sample No. 102, the diameter x1 of the holes was 0.08 mm, and the limit of the depth y1 of the holes was 0.43 mm.
In sample No. 103, the diameter x1 of the holes was 0.1 mm, and the limit of the depth y1 of the holes was 1.0 mm.
In sample No. 104, the diameter x1 of the holes was 0.3 mm, and the limit of the depth y1 of the holes was 3.0 mm.
In sample No. 105, the diameter x1 of the holes was 0.8 mm, and the limit of the depth y1 of the holes was 7.0 mm.
In sample No. 106, the diameter x1 of the holes was 1.5 mm, and the limit of the depth y1 of the holes was 30.0 mm.
In sample No. 107, the diameter x1 of the holes was 2.0 mm, and the limit of the depth y1 of the holes was 40.0 mm.
In sample No. 108, the diameter x1 of the holes was 3.0 mm, and the limit of the depth y1 of the holes was 50.0 mm.
The limit of the depth y1 is the limit of the depth of a hole with a diameter x1 that can be formed without breaking the drill.
[Evaluation]
Among samples Nos. 1 to 7 and samples Nos. 101 to 107, samples with the same hole diameter x1 are compared with each other. As shown in FIGS. 5 to 7, the depths y1 in samples Nos. 1 to 7 are larger than the depths y1 in samples Nos. 101 to 107, respectively, irrespective of the diameter x1.
Straight line L1 connecting the point for sample No. 101 and the point for sample No. 102 shown in FIG. 7 is y1=2.67x1+0.217. The gradient value and the intercept value have been rounded.
Straight line L2 connecting the point for sample No. 102 and the point for sample No. 103 shown in FIG. 6 is y1=28.5x1β1.85.
Straight line L3 connecting the point for sample No. 103 shown in FIG. 6 and the point for sample No. 104 shown in FIG. 5 is y1=10x1.
Straight line L4 connecting the point for sample No. 104 and the point for sample No. 105 shown in FIG. 5 is y1=8x1+0.6.
Straight line L5 connecting the point for sample No. 105 and the point for sample No. 106 shown in FIG. 5 is y1=32.9x1β19.3. The gradient value and the intercept value have been rounded.
Straight line L6 connecting the point for sample No. 106 and the point for sample No. 107 shown in FIG. 5 is y1=20x1.
Straight line L7 connecting the point for sample No. 107 and the point for sample No. 108 shown in FIG. 5 is y1=10Γ1+20.
As can be seen, the sintered members having holes and manufactured using the raw material powder containing the lubricant having a melting point or 150Β° C. or lower satisfy the following requirements (a1) to (a7).
( a β’ β’ 1 ) When β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 . ( a β’ β’ 2 ) When β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 . ( a β’ β’ 3 ) When β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1. ( a β’ β’ 4 ) When β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 . β’ ( a β’ β’ 5 ) When β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 . β’ ( a β’ β’ 6 ) When β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1. ( a β’ β’ 7 ) When β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20.
Straight line L8 connecting the point for sample No. 1 and the point for sample No. 2 shown in FIG. 7 is y1=13.3x1+0.267. The gradient value and the intercept value have been rounded.
Straight line L9 connecting the point for sample No. 2 and the point for sample No. 3 shown in FIG. 6 is y1=125x1β9.2. The gradient value and the intercept value have been rounded.
Straight line L10 connecting the point for sample No. 3 shown in FIG. 6 and the point for sample No. 4 shown in FIG. 5 is y1=13.5x1+1.95.
Straight line L11 connecting the point for sample No. 4 and the point for sample No. 5 shown in FIG. 5 is y1=18x1+0.6.
Straight line L12 connecting the point for sample No. 5 and the point for sample No. 6 shown in FIG. 5 is y1=50x1β25.
Straight line L13 connecting the point for sample No. 6 and the point for sample No. 7 shown in FIG. 5 is y1=40x1β10.
Straight line L14 passing through sample No. 7 shown in FIG. 5 and parallel to straight line L7 is y1=10x1+50.
As can be seen, the sintered members having holes and formed using the raw material powder containing the lubricant having a melting point or 150Β° C. or lower also satisfy the following requirements (a51) to (a56).
( a β’ β’ 5 β’ β’ 1 ) When β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 = 13.3 β’ β’ x β’ β’ 1 + 0.267 . ( a β’ β’ 52 ) When β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 = 125 β’ β’ x β’ β’ 1 - 9.2 . ( a β’ β’ 53 ) When β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 = 13.5 β’ x β’ β’ 1 + 1.95 . β’ ( a5 β’ β’ 4 ) When β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 = 18 β’ β’ x β’ β’ 1 + 0.6 . β’ ( a β’ β’ 55 ) When β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 = 50 β’ x β’ β’ 1 - 25. ( a β’ β’ 56 ) When β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 = 40 β’ β’ x β’ β’ 1 - 10. ( a β’ β’ 57 ) When β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 = 10 β’ β’ x β’ β’ 1 + 50.
Test Example 2
In Test Example 2, sintered members having grooves were manufactured, and the relation between the width x2 and depth y2 of the grooves was evaluated.
[Samples Nos. 21 to 25]
Sintered member samples Nos. 21 to 25 were manufactured using the same procedure as for sample No. 1 except that the green compact was grooved in step C to produce a workpiece having grooves.
[Step C]
The widths x2 of the grooves formed in samples Nos. 21 to 25 were 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, and 0.5 mm, respectively. The grooves with a width x2 of 0.05 mm or 0.1 mm were formed using a dicing blade. The grooves with a width x2 of 0.2 mm, 0.3 mm, or 0.5 mm were formed using a metal saw.
FIGS. 8 and 9 are graphs showing the relation between the width x2 and depth y2 of the grooves in each of samples Nos. 21 to 25. FIG. 9 is an enlarged graph of region C in FIG. 8. The horizontal axis of each of the graphs in FIGS. 8 and 9 represents the width x2 (mm) of grooves. The vertical axis of each of the graphs in FIGS. 8 and 9 represents the depth y2 (mm) of grooves. In the graphs in FIGS. 8 and 9, the results for samples Nos. 21 to 25 are shown using circles.
In sample No. 21, grooves with a width x2 of 0.05 mm and a depth y2 of 0.7 mm could be formed.
In sample No. 22, grooves with a width x2 of 0.1 mm and a depth y2 of 1.0 mm could be formed.
In sample No. 23, grooves with a width x2 of 0.2 mm and a depth y2 of 1.6 mm could be formed.
In sample No. 24, grooves with a width x2 of 0.3 mm and a depth y2 of 9.0 mm could be formed.
In sample No. 25, grooves with a width x2 of 0.5 mm and a depth y2 of 19.0 mm could be formed.
[Samples Nos. 201 to 207]
Sintered member samples Nos. 201 to 205 were manufactured using the same procedures as for samples Nos. 21 to 25, respectively, except that the lubricant was not used in step A. Sintered member samples Nos. 206 and 207 were manufactured using the same procedure as for sample No. 205 except that the width x2 of the groove formed in step C were changed to 1.5 mm or 3.0 mm. The grooves with a width x2 of 1.5 mm or 3.0 mm were formed using a grooving tool.
The graphs in FIGS. 8 and 9 show the relation between the width x2 and depth y2 of the grooves in each of samples Nos. 201 to 207. In the graphs in FIGS. 8 and 9, the results for samples Nos. 201 to 207 are shown using triangles.
In sample No. 201, the width x2 of the grooves was 0.05 mm, and the limit of the depth y2 of the grooves was 0.65 mm.
In sample No. 202, the width x2 of the grooves was 0.1 mm, and the limit of the depth y2 of the grooves was 0.9 mm.
In sample No. 203, the width x2 of the grooves was 0.2 mm, and the limit of the depth y2 of the grooves was 1.4 mm.
In sample No. 204, the width x2 of the grooves was 0.3 mm, and the limit of the depth y2 of the grooves was 3.0 mm.
In sample No. 205, the width x2 of the grooves was 0.5 mm, and the limit of the depth y2 of the grooves was 10.0 mm.
In sample No. 206, the width x2 of the grooves was 1.5 mm, and the limit of the depth y2 of the grooves was 15.0 mm.
In sample No. 207, the width x2 of the grooves was 3.0 mm, and the limit of the depth y2 of the grooves was 25.0 mm.
The limit of the depth y2 is the limit of the depth of a groove with a width x2 that can be formed without breaking the tool.
[Evaluation]
Among samples Nos. 21 to 25 and samples Nos. 201 to No. 205, samples with the same groove width x2 are compared with each other. As shown in FIGS. 8 and 9, the depths y2 in samples Nos. 21 to 25 are larger than the depths y2 in samples Nos. 201 to 205, respectively, irrespective of the width x2.
Straight line L21 connecting the point for sample No. 201 and the point for sample No. 203 shown in FIG. 9 is y2=5x2+0.4.
Straight line L222 connecting the point for sample No. 203 shown in FIG. 9 and the point for sample No. 205 shown in FIG. 8 is y2=28.7x2β4.3. The gradient value and the intercept value have been rounded.
Straight line L23 connecting the point for sample No. 205 and the point for sample No. 207 shown in FIG. 8 is y2=6x2+7.
As can be seen, the sintered members having grooves and formed using the raw material powder containing the lubricant having a melting point or 150Β° C. or lower satisfy the following requirements (b1) to (b3).
( b β’ β’ 1 ) When β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 . ( b β’ β’ 2 ) When β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 . ( b β’ β’ 3 ) When β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
Straight line L24 connecting the point for sample No. 21, the point for sample 22, and the point for sample No. 23 shown in FIG. 9 is y2=6x2+0.4.
Straight line L25 connecting the point for sample No. 23 shown in FIG. 9 and the point for sample No. 24 shown in FIG. 8 is y2=74x2β13.2.
Straight line L26 connecting the point for sample No. 24 and the point for sample No. 25 shown in FIG. 8 is y2=50x2β6.
Straight line L27 passing through sample No. 25 shown in FIG. 8 and parallel to straight line L23 is y2=6x2+16.
As can be seen, the sintered members having grooves and manufactured using the raw material powder containing the lubricant having a melting point or 150Β° C. or lower satisfy the following requirements (b51) to (b54).
( b β’ β’ 5 β’ β’ 1 ) When β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 = 6 β’ x β’ β’ 2 + 0.4 . ( b β’ β’ 52 ) When β’ β’ 0.2 β€ x β’ β’ 2 < 0.3 , y β’ β’ 2 = 74 β’ x β’ β’ 2 - 13.2 . ( b β’ β’ 53 ) When β’ β’ 0.3 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 = 50 β’ x β’ β’ 2 - 6. ( b β’ β’ 5 β’ β’ 4 ) When β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 = 6 β’ x β’ β’ 2 + 16.
Test Example 3
In Test Example 3, the number of holes that could be formed using one drill was evaluated.
[Samples Nos. 31 to 34 and Samples Nos. 301 to 304]
Sintered member samples Nos. 31 to 34 were manufactured using the same procedure as for sample No. 1 except that the diameter of the holes formed in the green compact in step C was different from that in sample No. 1. Sintered member samples Nos. 301 to 304 were manufactured using the same procedures as for samples Nos. 31 to 34, respectively, except that the lubricant was not used in step A.
[Step C]
The diameters of the holes formed in samples Nos. 31 to 34 were 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. The diameters of the holes formed in samples Nos. 301 to 304 were 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. When the holes having a diameter of 0.4 mm or 0.6 mm were formed, the cutting fluid was supplied by an external lubrication method. When the holes having a diameter of 0.8 mm or 1.0 mm were formed, the cutting fluid was supplied by an internal lubrication method. The depths of the holes formed in the samples were the same.
[Evaluation]
The number of holes that could be formed using one drill was counted. When the number of holes formed reached 20, the drilling was stopped. A numerical value less than 20 indicates the number of holes that could be formed without breaking the drill.
In sample No. 31, the number of 0.4 mm diameter holes that could be formed was 20.
In sample No. 32, the number of 0.6 mm diameter holes that could be formed was 20.
In sample No. 33, the number of 0.8 mm diameter holes that could be formed was 20.
In sample No. 34, the number of 1.0 mm diameter holes that could be formed was 20.
In sample No. 301, the number of 0.4 mm diameter holes that could be formed was 0.
In sample No. 302, the number of 0.6 mm diameter holes that could be formed was 1.
In sample No. 303, the number of 0.8 mm diameter holes that could be formed was 8.
In sample No. 304, the number of 1.0 mm diameter holes that could be formed was 18.
Among samples Nos. 31 to 34 and samples Nos. 301 to 304, samples with the same hole diameter are compared with each other. As can be seen, the smaller the diameter of the holes formed, the larger the difference between the number of holes formed when the raw material powder contained the lubricant with a melting point of 150Β° C. or lower and the number of holes formed when the raw material powder did not contain the lubricant with a melting point higher than 150Β° C.
Test Example 4
In Test Example 4, drills with particularly long flute lengths were prepared, and the upper limit of the depth of holes was evaluated.
[Samples Nos. 41 to 44]
Sintered member samples were manufactured using the same procedure as for sample No. 1 except that the processing conditions in step C were changed to those shown in Table 2.
[Step C]
In sample No. 41, a drill with a flute length L of 30 mm, a diameter D of 0.6 mm, and L/D of 50 was used to form holes. In sample No. 42, a drill with a flute length L of 40 mm, a diameter D of 0.8 mm, and L/D of 50 was used to form holes. In sample No. 43, a drill with a flute length L of 40 mm, a diameter D of 1.0 mm, and L/D of 40 was used to form holes. In sample No. 44, a drill with a flute length L of 50 mm, a diameter D of 1.0 mm, and L/D of 50 was used to form holes. In the graph in FIG. 5, the results for samples Nos. 41 to 44 are shown using circles.
| TABLE 2 | |||
| NUMBER | RELATION | ||
| OF | RELATION | BETWEEN |
| HOLE | STEPS | BETWEEN | DIAMETER |
| DIAMETER | DEPTH | NUMBER OF | FEED PER | FEED | STEP | NUMBER | DIAMETER | x1 AND | ||
| SAMPLE | x1 | y1 | REVOLUTIONS | REVOLUTION | SPEED | WIDTH | OF | x1 AND | FEED SPEED | |
| No. | mm | mm | y1/x1 | rpm | mm | mm/min | mm | TIMES | STEP WIDTH | /min |
| 41 | 0.6 | 30 | 50 | 9290 | 0.005 | 46 | 0.06 | 500 | 10 | 77 |
| 42 | 0.8 | 40 | 50 | 8276 | 0.02 | 166 | 0.3 | 134 | 3 | 207 |
| 43 | 1.0 | 40 | 40 | 6370 | 0.025 | 159 | 1 | 40 | 1 | 159 |
| 44 | 1.0 | 50 | 50 | 6370 | 0.03 | 191 | 1 | 50 | 1 | 191 |
[Evaluation]
In each sample, 320 holes could be continuously formed using one drill. During the formation of the holes, breakage of the drill and other machining problems did not occur. It can be inferred from these results that the upper limit of the depth y1 of holes is determined by a constraint on the availability of a drill usable as a tool. It was found that holes with y1/x1β₯50 can be obtained at least in the demonstrated range. From the above results, it is considered that a hole with y1/x1=60, y1/x1=80, and particularly about y1/x1=100 could be formed if a usable drill were obtained.
Straight line L40 connecting the point for sample No. 41, the point for sample No. 42, and the point for sample No. 44 shown in FIG. 5 is y1=50x1. The following are obtained by combining the results in Test Example 1 and the results in Test Example 4, with the upper limit set to y1/x1=50.
( a β’ β’ 3 ) W β’ hen β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 10 β’ β’ x β’ β’ 1. ( a β’ β’ 4 ) W β’ hen β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 . β’ ( a β’ β’ 5 ) W β’ hen β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 . β’ ( a β’ β’ 6 ) W β’ hen β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 20 β’ β’ x β’ β’ 1.
The following are obtained by combining the results in Test Example 1 and the results in Test Example 4, with the upper limit set to y1/x1=80.
( a β’ β’ 3 ) W β’ hen β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , 80 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 10 β’ β’ x β’ β’ 1. ( a β’ β’ 4 ) W β’ hen β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , 80 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 . β’ ( a β’ β’ 5 ) W β’ hen β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , 80 β’ x β’ β₯ y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 . β’ ( a β’ β’ 6 ) W β’ hen β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , 80 β’ x β’ β’ 1 β₯ y β’ β’ 1 > 20 β’ β’ x β’ β’ 1.
The following were found from the results in Test Examples 1 and 4.
A hole having a large depth y1 relative to the diameter x1 can be easily formed by step feed drilling.
No particular limitation is imposed on the upper limit of the number of steps, and the number of steps can be set appropriately so long as the machining time is not excessively long.
It is desirable that the smaller the diameter x1, the smaller the step width. For example, the step width is less than or equal to the diameter x1. The step width may be less than or equal to Β½ of the diameter x or may be less than or equal to β of the diameter x1.
It is desirable that the feed speed is less than or equal to 250 times the diameter x1.
The present invention is not limited to the above examples and is defined by the scope of the claims. It is intended that the present invention includes all modifications which fall within the scope and meaning equivalent to the scope of the claims.
In relation to the embodiments of the present invention described above, the following appendix is further disclosed.
APPENDIX 1
A sintered member composed of a metal,
-
- wherein the sintered member has a relative density of 95% or more, and
- wherein the sintered member has a hole having a diameter x1 (mm) and a depth y1 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a4) below:
( Ξ±1 ) when β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 β₯ 10 β’ β’ x β’ β’ 1 + 2 ; ( Ξ±2 ) when β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 β₯ 20 β’ β’ x β’ β’ 1 - 1 ; ( Ξ±3 ) when β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 β₯ 50 β’ x β’ β’ 1 - 25 ; and β’ β’ ( Ξ±4 ) when β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , 50 β’ x β’ β’ 1 β₯ y β’ β’ 1 β₯ 40 β’ β’ x β’ β’ 1 - 10.
The sintered member in appendix 1 has the hole with a large depth relative to its diameter.
REFERENCE SIGNS LIST
-
- 1 sintered member
- 2 hole
- 3 groove
- x1 diameter
- y1 depth
- x2 width
- y2 depth
- A, B, C region
- 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.-5. (canceled)
6. A sintered member composed of a metal,
wherein the sintered member has a relative density of 95% or more,
wherein the sintered member has a hole having a diameter x1 (mm) and a depth y1 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below:
( a β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 ; ( a β’ β’ 2 ) when β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 ; ( a β’ β’ 3 ) when β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 ; ( a β’ β’ 4 ) when β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 ; ( a β’ β’ 5 ) when β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 ; ( a β’ β’ 6 ) when β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1 ; β’ and ( a β’ β’ 7 ) when β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20.
7. A sintered member composed of a metal,
wherein the sintered member has a relative density of 95% or more,
wherein the sintered member has a groove having a width x2 (mm) and a depth y2 (mm), the width x2 and the depth y2 satisfying requirements (b1) to (b3) below;
( b β’ β’ 1 ) w β’ hen β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 ; ( b β’ β’ 2 ) w β’ hen β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 ; and ( b β’ β’ 3 ) w β’ hen β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
8. The sintered member according to claim 6, wherein the metal is pure iron or an iron alloy.
9. The sintered member according to claim 6, wherein the metal is stainless steel.
10. The sintered member according to claim 6, wherein the relative density is 97% or more.
11. The sintered member according to claim 7, wherein the metal is pure iron or an iron alloy.
12. The sintered member according to claim 7, wherein the metal is stainless steel.
13. The sintered member according to claim 7, wherein the relative density is 97% or more.
14. A method of manufacturing a sintered member, the method comprising:
preparing a raw material powder containing a metal powder and a lubricant;
pressing the raw material powder to produce a green compact having a relative density of 95% or more;
subjecting the green compact to hole drilling to produce a workpiece having a hole having a diameter x1 (mm) and a depth y1 (mm), the diameter x1 and the depth y1 satisfying requirements (a1) to (a7) below; and
sintering the workpiece,
wherein the ratio of the lubricant contained in the raw material powder is 0.025% by mass to 0.2% by mass, and
wherein the lubricant has a melting point of 150Β° C. or lower:
( a β’ β’ 1 ) when β’ β’ 0.05 β€ x β’ β’ 1 < 0.08 , y β’ β’ 1 > 2.67 β’ β’ x β’ β’ 1 + 0.217 ; ( a β’ β’ 2 ) when β’ β’ 0.08 β€ x β’ β’ 1 < 0.1 , y β’ β’ 1 > 28.5 β’ β’ x β’ β’ 1 - 1.85 ; ( a β’ β’ 3 ) when β’ β’ 0.1 β€ x β’ β’ 1 < 0.3 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 ; ( a β’ β’ 4 ) when β’ β’ 0.3 β€ x β’ β’ 1 < 0.8 , y β’ β’ 1 > 8 β’ β’ x β’ β’ 1 + 0.6 ; ( a β’ β’ 5 ) when β’ β’ 0.8 β€ x β’ β’ 1 < 1.5 , y β’ β’ 1 > 32.9 β’ x β’ β’ 1 - 19.3 ; ( a β’ β’ 6 ) when β’ β’ 1.5 β€ x β’ β’ 1 < 2.0 , y β’ β’ 1 > 20 β’ β’ x β’ β’ 1 ; β’ and ( a β’ β’ 7 ) when β’ β’ 2.0 β€ x β’ β’ 1 , y β’ β’ 1 > 10 β’ β’ x β’ β’ 1 + 20.
15. A method of manufacturing a sintered member, the method comprising:
preparing a raw material powder containing a metal powder and a lubricant;
pressing the raw material powder to produce a green compact having a relative density of 95% or more;
subjecting the green compact to grooving to produce a workpiece having a groove having a width x2 (mm) and a depth y2 (mm), the width x2 and the depth y2 satisfying requirements (b1) to (b3) below; and
sintering the workpiece,
wherein the ratio of the lubricant contained in the raw material powder is 0.025% by mass to 0.2% by mass, and
wherein the lubricant has a melting point of 150Β° C. or lower:
( b β’ β’ 1 ) w β’ hen β’ β’ 0.05 β€ x β’ β’ 2 < 0.2 , y β’ β’ 2 > 5 β’ β’ x β’ β’ 2 + 0.4 ; ( b β’ β’ 2 ) w β’ hen β’ β’ 0.2 β€ x β’ β’ 2 < 0.5 , y β’ β’ 2 > 28.7 β’ x β’ β’ 2 - 4.3 ; and ( b β’ β’ 3 ) w β’ hen β’ β’ 0.5 β€ x β’ β’ 2 , y β’ β’ 2 > 6 β’ β’ x β’ β’ 2 + 7.
16. The method of manufacturing a sintered member according to claim 14, wherein the hole drilling is step feed drilling.
17. The method of manufacturing a sintered member according to claim 14, wherein the lubricant is stearic acid, erucic acid amide, or stearic acid amide.
18. The method of manufacturing a sintered member according to claim 15, wherein the lubricant is stearic acid, erucic acid amide, or stearic acid amide.
Images & Drawings included:
Sources:
- United States Patent and Trademark Office - verify current appl. status at the USPTOβ
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