JP2617334B2 - Sintered alloy material and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a sintered alloy material and a method for producing the same, which are excellent in both strength and corrosion resistance, have good adaptability to a mating member such as a shaft material, and have a small friction coefficient. It is an object of the present invention to provide a sintered alloy material having excellent performance as a bearing material or the like and a method for producing the same.

(Industrial application fields) Sintered oil-impregnated bearings and other sintered alloy materials and their manufacturing technologies.

(Conventional technology) For sintered oil-impregnated bearings, JIS B 15
As specified in 81-1976, bearing materials such as cylindrical, flanged cylindrical and spherical used for household electrical equipment, audio equipment, office machinery, agricultural machinery, automobiles and other transporting and handling equipment, etc. It is variously defined, and its main component composition is pure iron, iron-copper, iron-carbon, iron-copper-carbon, iron-copper-lead, bronze, copper, lead-bronze. The materials and types are relatively diverse.

In addition, for example, in Japanese Patent Application Laid-Open No. 56-51554, sintering a green compact using iron powder and brass powder is disclosed, and the present inventors further disclosed in Japanese Patent Application Laid-Open No. 60-200927. It has been proposed to use an iron powder, a brass powder, and a nickel-white powder, and to perform a sintering process on a green compact formed of a mixture thereof in a reducing atmosphere.

In Japanese Patent Application Laid-Open No. 56-90954, the present inventors have also proposed compacting and sintering a raw material powder obtained by mixing a bronze powder with an iron powder.

(Problems to be Solved by the Invention) The above oil-impregnated bearings mainly composed of iron are excellent in skeletal strength and are preferable for high loads, but are limited in use because they are inferior in compatibility and corrosion resistance to mating members. .

On the other hand, a material mainly composed of copper or bronze has good adaptability and corrosion resistance, but is not suitable for high loads because of insufficient strength.

Iron-copper alloys (including iron-copper-lead, iron-copper-carbon, etc.) have intermediate properties between them, but are still insufficient in strength and corrosion resistance.

In the case of using iron powder and brass powder or iron powder and bronze powder according to the above-mentioned JP-A-56-51554 and JP-A-56-90954, the strength and conformability to the mating member are preferable even if the corrosion resistance is preferable. Is not enough.

Japanese Patent Application Laid-Open No. Sho 60-200927 aims at achieving sufficient corrosion resistance and reducing the friction coefficient while securing strength by using nickel silver, but it does not always satisfy those characteristics. In addition, it is insufficient in conformity to a mating member such as a shaft.

Furthermore, in order to obtain an appropriate strength and obtain a product at a relatively low cost in the above-mentioned conventional products, it is essential to use a considerable amount of iron powder. Even if buried in copper powder or brass powder, it must be exposed to some extent, and the iron powder particles exposed in this way will rub against the mating member and wear it, and It is a starting point for occurrence.

That is, in the case of the conventional method as described above, as the mixing amount of the copper powder or the like increases, the color sensation due to the added copper powder or the like gradually takes on, and the feel is different from the product using only the iron powder. When observed microscopically, each raw material powder (iron powder and copper powder, etc.) is exposed in a state substantially according to the mixing ratio, and such products are subjected to a corrosion resistance test. However, even if the corrosion is reduced in a portion such as copper powder, the corrosion easily occurs and proceeds in an iron powder portion. The same applies to the wear to the mating member and the like, and the exposed iron powder itself must inevitably give the shaft material and the like wear as iron.

"Constitution of the Invention" (Means for solving the problem) 1. Fe: 20 to 64 wt%, Cu: 27 to 59 wt%, Zn: 6 to 24 wt%, Sn:
It contains 0.06 to 0.6 wt%, Al: tr to 3 wt%, and Mn: 0.1 to 3 wt%, and has a coverage of 90% on the surface of the iron powder particles by Fe.
A sintered alloy material having a porosity of 15 to 28 vol%, characterized by being coated with at least Cu.

2.Fe: 20 ~ 64wt%, Cu: 24.2 ~ 58.7wt%, Zn: 4.5 ~ 23.8wt
%, Sn: 0.05 to 0.6 wt%, Al: tr to 2.98 wt%, Mn: 0.08 to 2.98 wt%, and one kind of solid lubricants such as graphite, molybdenum disulfide, and lead Alternatively, it is characterized in that the surface of the iron powder particles of Fe is coated with Cu having a coating ratio of 90% or more, and the porosity is 15 to 28.
Sintered alloy material with vol%.

3. It is characterized by using 100 parts by weight of iron powder coated with 20 to 50% by weight of copper and having a coating rate of 90% or more. Zn: 30 to 40% by weight, Sn: 0.3 to 1% by weight based on the copper coated iron powder. , Al: tr ~ 5wt
%, Mn: 0.5 to 5% by weight, the balance being 25 to 150 parts by weight of manganese bronze powder containing Cu and unavoidable impurities added, mixed, compacted and sintered, and then porosity 15
A method for producing a sintered alloy material by sizing to ~ 28vol%.

4. The sintered alloy according to claim 3, wherein the green compact obtained by compacting the raw material powder is housed in a heat-resistant container, covered, and sintered in a reducing atmosphere at 800 to 950 ° C. The method of manufacturing the material.

5. It is characterized by using 100 parts by weight of iron powder in which 20% to 50% by weight of copper is coated at a coating rate of 90% or more, based on the copper-coated iron powder, Zn: 30 to 40% by weight, and Sn: 0.3 to 1% by weight. , Al: tr ~ 5wt
%, Mn: 0.5 to 5 wt%, the balance being 19.7 to 149.5 parts by weight of manganese bronze powder consisting of Cu and inevitable impurities and one of solid lubricants such as graphite, molybdenum disulfide or lead.
The raw material powder obtained by adding and mixing 0.5 to 5.3 parts by weight of a seed or two or more kinds is compacted, sintered, and then has a porosity of 15 to 28 vol.
A method for producing a sintered alloy material by sizing to%.

6. The powder compact obtained by compacting the raw material powder is housed in a heat-resistant container in a state separated from the bottom surface and covered,
The method for producing a sintered alloy material according to claim 5, wherein the sintering is performed in a reducing atmosphere at 800 to 950 ° C.

(Action) Fe: 20 to 64 wt%, Cu: 27 to 59 wt%, Zn: 6 to 24 wt%, Sn:
0.06 to 0.6 wt%, Al: 3 wt% to 3 wt%, and Mn: 0.1
~ 3wt%, and the surface of the powder particles of Fe is C
By being coated in a substantially perfect state with a coverage of 90% or more by u, the Fe particles are not exposed on the product surface while ensuring the strength by the Fe powder particles. It becomes densely coated, so that the corrosion resistance is greatly improved, and the conformability to the mating member and the thermal conductivity are also improved. As for the sintering between powder particles, a stable sintering relationship is formed because there is no intervention of Fe particles.

If Fe is less than 20% by weight, sufficient strength as a sintered body cannot be obtained, and other components are required in a large amount, resulting in high cost. While 64
A steel containing more than wt% of Fe increases the coefficient of friction, does not ensure conformability to a mating member, and rapidly deteriorates corrosion resistance.

Fe reaches 64 wt% when Cu becomes 27 wt% or more
Complete coverage of the particle surface and ensure conformability,
By setting the upper limit to 59 wt%, Fe particles and the like can be contained in an appropriately high blending amount to maintain the strength and obtain low cost.

When Zn is 6 wt% or more, corrosion resistance is secured in combination with Cu and Mn, and when the upper limit is 24 wt%, conformability is appropriately maintained. When Mn is 0.1 wt% or more, strength and corrosion resistance are effectively increased from its deoxidizing action. on the other hand
By setting the upper limit to 3 wt%, conformability is maintained and an increase in the coefficient of friction is suppressed.

By containing Sn at 0.06% or more, Cu, Mn and
The properties of manganese bronze as a copper-based high-strength alloy can be exhibited in combination with the proper content of Al and Zn. In the case of the present invention in which a core such as manganese bronze, which is also a copper-based high-strength alloy, is made into a nucleus of Fe powder particles coated in a substantially perfect state with Cu, the Sn content is 0.6 wt%. Even if it is contained in excess, the effect is saturated, and in particular, no further characteristics are required, resulting in an increase in cost. That is, by setting the upper limit to 0.6 wt%, it is possible to obtain low cost using a considerable amount of iron powder particles.

By containing 0 to 3 wt% of Al, the component composition of manganese bronze as a copper-based high-strength alloy as described above is secured between the iron powder particles. The content of Al exceeding 3 wt% tends to lower the strength. Regarding the lower limit of Al, for example, as specified in Table 2 of JIS H2205, manganese bronze powder containing up to 5.0 wt% may be used, and as a product, it may be contained up to 3.0 wt% as described above. However, even in the case of substantially a trace, high strength characteristics as manganese bronze may be required, and it can be said that there is no particular limitation.

As described above, the copper-coated iron powder particles and the copper-based high-strength alloy powder as manganese bronze are appropriately sintered at a sintering temperature of 800 to 950 ° C.

The powder compact is housed in a state separated from the bottom surface of the heat-resistant container, covered with a lid, and sintered to prevent the loss of air diffusion of the Zn even under the condition containing Zn, and furthermore, the uniform Form a sintered state.

After compacting and sintering, the porosity is adjusted to 15 vol% or more to obtain an appropriate oil content when used as a bearing material and enhance lubrication performance. On the other hand, the porosity is 28vo
By not exceeding l%, the strength is secured and the impregnating oil is prevented from flowing out and scattering.

Lubricity is increased and the coefficient of friction is reduced by containing 0.5 wt% or more of one or more solid lubricants such as graphite, molybdenum disulfide or lead. Also, the strength of the product is maintained by not exceeding 5.0 wt%.

Zn: 30-40 wt%, Sn: 0.3-1 wt%, Al: 0-5 wt%, Mn: 0.
By using manganese bronze powder containing 5 to 5 wt% and the balance consisting of Cu and unavoidable impurities, Cu and Zn and Mn are removed.
Sn or Al is added at the same time as an alloy body, and the trouble of preparing these components separately and mixing them sequentially is avoided.
Further, segregation of each compounded component is appropriately prevented, and a uniform mixed and sintered state is easily formed. Also, since such manganese bronze is a copper-based alloy, it was coated on iron particles as described above.
It has good compatibility with the Cu layer and has a stable sintering mechanism. That is, the iron powder particles are familiar with manganese bronze having high strength, and constitute a structure that is firmly and stably bonded.

(Examples) To explain a specific embodiment of the present invention as described above, the present invention is basically a sintered alloy containing Mn, Sn, and optionally Al together with Fe, Cu, Zn. It is adopted that the Fe powder is coated with Cu in a substantially complete state with a coverage of 90% or more. As described above, other components may be prepared as alloys.
Each powder of an alloy and brass, an electric resistance alloy that is an alloy of manganese and copper, each powder of a magnetic alloy, iron and Zn, and the like can be used. However, the preferred material is pure iron powder.
The use of copper coated manganese bronze powder.

Fe as a product is generally 20 to 64% by weight, preferably 30 to 60% by weight, and more preferably 40 to 55% by weight. Cu is generally 27 to 59% by weight as described above, but is preferably 25 to 55% by weight, more preferably 30 to 50% by weight.
Should be. The general range for Zn is 6-24 wt%, but preferably 8-24 wt%, more preferably 10-20 wt%.
It is. A preferred range for Mn is 0.1 to 3 wt%, more preferably 0.5 to 2 wt% in the general range described above.
It is. Al may be contained up to 3 wt%, but may not be contained at all.

The above-mentioned iron powder is prepared as coated with at least a part of the above-mentioned Cu content. Such coating of iron powder with copper is performed by a plating method or the like, and such a coating amount can be performed to an appropriate degree by appropriately selecting the amount of electricity and time during plating. As described above, the coating amount of copper is 20 to 50% by weight, but a more preferable range is about 25 to 45%. With such copper coating, the peripheral surface of the iron powder particles is completely covered with the copper film, and the iron powder particles can be obtained as having moderately rounded irregularities particularly during plating. This facilitates green compaction.

The size of the iron powder particles as the raw material is not particularly limited, but a particle range that is larger than 100 mesh or less, which is conventionally generally used for manufacturing a pure iron-based sintered body, should be used. Can be. That is, for example, even relatively fine particles such as 150 mesh or less can be treated in the same manner as those in the conventional general range in terms of particle size by increasing the diameter by copper coating. Therefore, even a powder having a large diameter exceeding the conventional particle size range can be formed to the same or more easily by a compacting process similar to the conventional method.

The coating of Cu on the iron powder particles as described above can employ an immersion method, a vapor deposition method, or other appropriate method in addition to electrolytic plating.
It forms a substantially complete coverage of 95% or more, at least 90% or more, preferably 98% or more.

In the present invention, the component composition of manganese bronze, which is a copper-based high-strength alloy, is formed between iron powder particles coated with copper as described above, and manganese bronze, which is such a copper-based high-strength alloy Can be formed using a plurality of material powders, but a preferred method is to use manganese bronze powder. That is, as such manganese bronze, for example, as defined in JIS H2205, Zn: 30 ~
40wt%, Sn: 0.3-1wt%, Al: 0.5-5wt%, Mn: 0.5-5wt
%, With the balance being widely known, such as Cu, and manganese bronze powder containing no Al as in the production examples described below. The manganese bronze is positioned between the copper-coated iron powder particles as described above (mixed), compacted and sintered, or further sized so that appropriate sintering between the copper-based particles is achieved and stable and A strong sintered structure is obtained, and the product has high mechanical strength.

Naturally, graphite and molybdenum disulfide as solid lubricants are added as powders, but solid lubricants such as graphite have a small specific gravity with respect to both copper-coated iron powder and manganese bronze powder. Therefore, it is difficult to uniformly disperse such raw materials such as graphite in other raw material powders, and it is difficult to disperse the graphite during loading and unloading, changing to a press hopper, and compacting. Floating of powder,
Segregation occurs due to offset or the like. Therefore, for solid lubricants such as graphite, a relatively coarse powder is used,
In addition, it was confirmed by experiments that the use of a material obtained by classifying and removing the fine powder was effective. That is, the commercially available graphite powder is generally 1 to 30 μm, or 1 to 50 μm, whereas the preferred solid lubricant of the present inventors is 10 to 150 μm, particularly 20 μm.
~ 100μm, coarse powder and 10μm or 20μ
m or less, thereby facilitating uniform dispersion and preventing segregation during handling and other handling as much as possible. Fine particles having a particle size of less than 10 μm or less than 20 μm as described above do not generate dust in a classification treatment in a liquid, and can be appropriately classified.

In the present invention, a metal or alloy powder other than the above may be added as needed. That is, for example, Pb,
Even if a small amount of Ni, Si, etc. is contained, the characteristics of the present invention are not lost, and Sn-containing brass, Al-containing brass, Pb-containing brass, Ni-containing brass, Fe-containing brass, Si-containing brass, etc. are used as alloys. Can be.

Powder compaction is generally performed under a pressure of about ² to 3 Ton / cm ² , and its porosity is 22 to 35 vol%. When the content is less than 22 vol%, it is difficult to perform effective sizing and obtain a product having a porosity suitable for oil impregnation and the like. On the other hand, a green compact having a porosity exceeding 35 vol% is highly likely to be damaged or broken during sintering. Sintering is performed in a reducing atmosphere at 800 to 950 ° C, but in order to prevent the volatilization and dezincification of Zn contained as described above, place a mesh material etc. in a heat-resistant container and separate from the bottom surface. It is preferred to house, cover and sinter. Of course, it may be buried in carbon powder.

In the case of the present invention in which manganese bronze is deformed as a result of sintering, distortion, deformation, and dimensional change are manifested as such, so that the product is sized to a predetermined size. In addition, the porosity
By using a product of 15 to 28 vol%, a preferable oil content for obtaining an oil-impregnated bearing can be obtained, and a sintered metal body having an appropriate value of mechanical strength or the like can be obtained.

A specific production example according to the present invention will be described below.

Production Example 1. Cu-coated iron powder obtained by coating iron powder having a particle size of 100 mesh or less with 40 wt% of Cu by plating, Cu: 64.5 wt%, Zn:
Manganese bronze powder containing 30 wt%, Sn: 0.5 wt%, and Mn: 5 wt% and having a mesh size of 100 mesh or less was prepared, and these were mixed with the following wt% as shown in Table 1.

Each of the raw material powders (1) to (6) according to Table 1 above is sufficiently mixed and then compacted, that is, the outer diameter is 10 mm, and the inner diameter is 10 mm.
It was molded as a 4 mm annular bearing. Each of these compacts is divided into groups and stored in a heat-resistant iron box with a metal mesh laid on the bottom, that is, the sintering body is stored in a state separated from the bottom of the container, and a cover is provided. Then, it was charged into a sintering furnace, and subjected to sintering treatment in a reducing atmosphere at 890 ° C. with AX gas for 45 minutes. Each of the sintered bodies thus obtained was then subjected to sizing to obtain a product having a constant porosity of 20 vol%. Examination of such a product using a magnifying glass revealed that all of the iron powder particles were covered with a copper layer in an almost complete state of 98% or more of the peripheral surface, and the exposed portion could not be observed substantially. .

The composition of each of the sintered bodies thus obtained was examined. The results are shown in Table 2 below.

Each product obtained as described above was then immersed, that is, the air in the pores was removed under a vacuum condition of about -30 mmHg and impregnated with turbine oil to obtain an oil-impregnated bearing.

These products were subjected to characteristic tests. That is, each product as described above, pure iron-based sintered bearing according to the prior art separately as a comparative material and pure iron powder and brass powder were mixed at a ratio of 50:50, compacted, and sintered. The same porosity of each of the above-mentioned products was prepared to have the same porosity of 20 vol%, and radial crushing strength, friction coefficient and PV value of these products and comparative materials were 1000 kg / cm ² · m
The result of measurement of the temperature rise during continuous rotation for 40 minutes at min (the temperature gradually rises up to about 30 minutes under this condition, but hardly rises thereafter) is shown in Table 3 below. is there.

Table 4 shows the results of the corrosion resistance test of each of the products according to the present invention and the comparative material as described above at a humidity of 80% and a temperature of 60 ° C., and the measurement of the period until the occurrence of rust was observed. Was.

Manufacture example 2 In the composition of Table 1 in the manufacture example 1 described above, except that the graphite powder was contained at 2 wt% in the outer case, all were carried out in the same manner as in manufacture example 1 to obtain a product.

The coefficient of friction for this product was 0.068, and it was confirmed that it had better lubricity.
kg / mm ² , having a preferable strength, and it was confirmed that the rust test under the condition of high temperature and high humidity was the same as that of Production Example 1.

Production Example 3 For 100 parts of the same copper-coated iron powder as in Production Example 1, Cu:
Except for mixing 25 parts of manganese bronze powder of 63.8%, Zn: 29.7%, Mn: 5%, Sn: 0.5%, and Al: 1.0%, all were compacted and sintered in the same manner as in Production Example 1, and 20vol %, And impregnated with turbine oil to obtain an oil-impregnated bearing.

The result of a characteristic test on this product showed that the radial crushing strength was
29.5 kg / mm ^2, the friction coefficient 0.075, continuous rotation temperature rise value is 2
1.2 ° C., the same as that of Production Example 1 described above, and the number of days in which rust was observed was 120 days or more, and even if a general manganese bronze powder containing Al as such was used as it is. It was confirmed that a favorable product was obtained.

[Effect of the Invention] According to the present invention as described above, the iron powder particles coated with Cu are used so that the iron powder particles have both favorable conformability to a mating member such as a shaft and excellent corrosion resistance while having excellent corrosion resistance. In addition, it is possible to provide a sintered alloy material having excellent properties in strength since manganese bronze as a high-strength copper alloy is stably and firmly bonded, and to provide a preferable production method thereof. Thus, the invention is industrially effective.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C22C 38/14 C22C 38/14

Claims (6)

(57) [Claims] (1) Fe: 20 to 64% by weight, Cu: 27 to 59% by weight, Zn: 6 to 24%
wt., Sn: 0.06 to 0.6 wt.%, Al: tr. to 3 wt.%, Mn: 0.1 to 3 wt.
A sintered alloy material having a porosity of 15 to 28 vol%, characterized by being coated with at least Cu. 2. Fe: 20-64 wt%, Cu: 24.2-58.7 wt%, Zn:
4.5-23.8wt%, Sn: 0.05-0.6wt%, Al: tr-2.98wt%, Mn: 0.08-2.98wt%, and solid lubrication such as graphite, molybdenum disulfide, lead One or two or more of the materials contain 0.5 to 5% by weight, and the iron powder particles made of Fe are coated with Cu at a coverage of 90% or more, and have a porosity of 15 to 28.
Sintered alloy material with vol%. 3. The method according to claim 1, wherein 100 to 100 parts by weight of iron powder coated with 20 to 50% by weight of copper and having a coating rate of 90% or more is used. : 0.3-1wt%, A
l: The raw material powder containing 25 to 150 parts by weight of manganese bronze powder containing tr to 5 wt%, Mn: 0.5 to 5 wt%, and the balance being Cu and unavoidable impurities, is sintered, and then sintered. Then, a method for producing a sintered alloy material, which comprises sizing to a porosity of 15 to 28 vol%. 4. The method according to claim 3, wherein the green compact obtained by compacting the raw material powder is accommodated in a heat-resistant container, covered, and sintered in a reducing atmosphere at 800 to 950 ° C. Manufacturing method of sintered alloy material. 5. The method according to claim 1, wherein 100 parts by weight of iron powder coated with 20 to 50% by weight of copper and having a coating rate of 90% or more is used. Zn: 30 to 40% by weight, Sn : 0.3-1wt%, A
l: 19.7 to 149.5 parts by weight of manganese bronze powder containing tr to 5 wt% and Mn: 0.5 to 5 wt%, with the balance being Cu and inevitable impurities, and one of solid lubricants such as graphite, molybdenum disulfide or lead. The raw material powder obtained by adding and mixing 0.5 to 5.3 parts by weight of one or more kinds is compacted, sintered, and then porosity 15
A method for producing a sintered alloy material by sizing to ~ 28vol%. 6. A green compact obtained by compacting raw material powder is housed in a heat-resistant container at a distance from the bottom surface and covered, and sintered in a reducing atmosphere at 800 to 950 ° C. The method for producing a sintered alloy material according to claim 5.