JPS6164838A - High density copper sintered alloy - Google Patents

Abstract

PURPOSE:To obtain the titled alloy superior in resistances to wear, burning and pitching, by dispersing a specified ratio of fine hard particles composed of iron alloy having a specified compsn. in matrix structure of a Cu alloy contg. a specified quantity of Ni. CONSTITUTION:Into the Cu alloy contg. by weight ratio 5-50% Ni as matrix structure, fine hard particles composed of at least >=one kind among 0.2-3.5% C, 0.5-25% Cr, 0.3-7.0% Mo, 0.5-25% W, 0.2-6.0% V, 0.5-18% Co, 0.2-3.0% Ni, <=1.2% Mn and the balance Fe with inevitable impurities are dispersed by 10-70wt% to prepare the Cu sintered alloy. By regulating hardness of fine hard particles to >=200 Hv, average particle diameter to 5-150mu and performing conventional powder press molding and heating, sintering, the titled alloy having sintered density of >=90% of theoretical density is manufactured easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high-density copper-based sintered alloy, and more specifically,
- By dispersing fine hard particles with a specific composition in the matrix structure consisting of Nt-based alloys, it has excellent wear resistance, seizure resistance, and pitting resistance, making it possible to withstand harsh usage conditions. The present invention relates to a high-density copper-based sintered alloy that can be suitably applied as a sliding member etc. that slides on the surface.

[Conventional technology]

Sintered parts are manufactured by compacting metal powder raw materials for powder metallurgy using a mold, etc., and then baking and solidifying them in a heating sintering furnace.Because of their high productivity and excellent product precision, they are used for automobiles. It is widely used for parts, etc.

Sintered alloys generally include iron-based sintered alloys and copper-based sintered alloys, and sintered bearing alloys, which are representative sintered alloys, are classified as iron-based sintered alloys in JIS standard B1581. A copper-based sintered alloy is specified.

Copper-based sintered alloys generally have excellent seizure resistance, so they are widely used in bearing parts, etc.; however, because of their poor wear resistance, they are used in sliding parts that are subjected to high loads. It was considered difficult to apply to such cases.

On the other hand, although iron-based sintered alloys have excellent wear resistance, they have poor seizure resistance, so if they are used as sliding members in areas where lubricating oil is likely to be insufficiently supplied, they are prone to seizure. there were.

Therefore, in order to compensate for the drawbacks of the conventional copper-based sintered alloy and iron-based sintered alloy as mentioned above, iron-based alloy powder and copper-based alloy powder are mixed to form a mixed powder raw material for powder metallurgy, and then pressed. Copper-iron based sintered alloys manufactured by powder molding and heating sintering have been developed (for example, Japanese Patent Publication No. 56-52988, etc.).

In this copper/iron-based sintered alloy, a mixed powder is prepared by mixing iron-based alloy powder with copper-based alloy powder at a weight ratio of 10 to 40%, and a small amount of tin and molybdenum disulfide. It is intended to improve wear resistance and lubrication properties by compacting and heating and sintering the powder as a mixed powder raw material for powder metallurgy.

However, in the sliding parts used in recent high-load engines, etc., the performance of recent engines (high speed rotation,
As the usage conditions become more severe with the increase in output (high output), even with the above-mentioned copper-iron sintered alloy (Special Publication No. 56-52988), it is not always necessary to ensure sufficient sliding performance and durability. It is the current Hakuinu that has not been able to do this.

By the way, in the Cu-5n alloy that constitutes the matrix structure of copper-based sintered alloys that are generally used as bearing members, 1. Since the volume expands slightly during the heating and sintering process, the density of the sintered compact becomes almost the same as the density of the compacted compact. Therefore, in order to make the density of the sintered compact 90% or more of the theoretical density, in advance, The density of the powder compact is 90% of the theoretical density.
% or more.

Therefore, in order to make the powder compact have such a high density,
It is necessary to make the pressure during powder compaction significantly higher than the pressure during powder compaction (3 to 7 ton/cm'') for ordinary copper-based sintered alloys.

However, the mold for compacting the compacted product is baked.

Considering mold wear, operational safety, etc., it is extremely difficult in practice to increase the pressure force during powder compaction to a high pressure force exceeding 7 ton/cm, and practically it is almost impossible. It will be close to.

From the above background, it is necessary to add a new process in order to ensure a sintered compact density of 90% or more of the theoretical density by using a Cu-5n alloy as the alloy that constitutes the base structure of the copper-based sintered alloy. It becomes.

That is, one way to increase the density of such a sintered body is to
Although it is possible to repressurize after heating and sintering, adding the repressing step would significantly increase the manufacturing cost of the manufactured sintered alloy, so this is not a practical method.

Therefore, the present inventors have developed a copper-based sintered alloy based on the results of repeated research to solve the problems in copper-based sintered alloy using such a Cu-5n alloy as a base structure alloy. We have developed a Cu-Ni alloy as an alloy for the matrix structure.

[Problem that the invention seeks to solve]

In view of the current state of the conventional technology as described above, the problem that the present invention attempts to solve is that although conventional copper-based sintered alloys have excellent seizure resistance and are widely used for bearing members, etc., Due to its poor abrasion resistance, it is difficult to be used in sliding parts that are subject to high loads.Furthermore, although iron-based sintered alloys have excellent wear resistance, they have poor seizure resistance. If used as a sliding member in areas where the supply of lubricating oil, etc. is likely to be insufficient, seizure is likely to occur. However, it is not always possible to ensure sufficient sliding characteristics and durability for sliding members used in recent high-load engines and the like.

Therefore, the technical problem of the present invention is to
By using the i-series alloy as the base structure alloy, it is possible to ensure excellent seizure resistance and pitting resistance, as well as to maintain this carbon
An appropriate amount of fine hard particles with a specific composition is dispersed in the base structure of the u-Ni alloy to provide excellent wear resistance and maintain excellent sliding properties even under severe usage conditions. As a result, although it is a copper-based sintered alloy, it has excellent wear resistance and can be suitably used as a sliding member.

[Means for solving problems]

In view of such problems in the conventional technology, the means for solving the problems in the conventional technology in the present invention are as follows:
In a base structure consisting of a copper-based alloy containing Ni; 5 to 50% by weight, C; 0.2 to 3.5% and Cr.
; 0.5-25% 2Mo; 0.3-7.0%, W, 0.
5-25%, V; 0.2-6゜0%, Co; 0.5-1
8%, Ni; 0.2-3°0%.

Mn: at least one type from 1.2% or less,
A high-density copper-based sintered alloy characterized by fine hard particles consisting of Fe and unavoidable impurities in a weight ratio of 10 to 70%, and a weight ratio of Ni; 5 to 50.
In the base structure consisting of a copper-based alloy containing %C;
．． 2-3.5%, and.

Cr: 0.5-25%, Mo: 0.3-7.0%
, W; 0.5-25%, V, 0.2-6.0%, Co;
0.5-18%, N1H0.2-3.0%, Nb, 0.
05-3゜0%, B; 0.03-0.5%, P; 0.1
~0.8%.

Fine hard particles consisting of at least one type of Mn: 1.2% or less, Si: 1.5% or less, the remainder unavoidable impurities, and Fe in a weight ratio of 10 to 70% to 70%.
It is made of a high-density copper-based sintered alloy characterized by a

[Effect]

Hereinafter, the effects of the present invention will be explained.

In the present invention, the alloy constituting the base structure is Cu-Ni.
The reason why this alloy is used is that the density of the sintered body becomes higher than the density of the compacted body because this alloy causes volumetric shrinkage during the heating sintering process and the dimensions of the sintered body shrink. This is an important feature of the material of the present invention.

Furthermore, since the liquid phase formation temperature of the Cu-Ni alloy that constitutes the matrix structure is higher than the melting point of conventional copper alloys, copper-based It becomes possible to perform heating and sintering at a higher temperature than the heating and sintering temperature of the sintered alloy, and it also becomes possible to form a stronger sintered body.

Due to the characteristics of the Cu-Ni alloy constituting the base structure described above, the high-density copper-based sintered alloy of the present invention can be made by ordinary powder compacting, even if the sintered body density is 90% or more of the theoretical density. It can be easily manufactured using a heating and sintering process, and excellent pitting resistance can be ensured.

In addition, in the high-density copper-based sintered alloy of the present invention, since Ni is added to the copper-based alloy constituting the base structure as described above, the hardness of the base structure is improved and the wear resistance is improved. It also has an effective effect on improving.

However, when the amount of Ni added in the high-density copper-based sintered alloy of the present invention is less than 5%, the effect of improving the hardness of the base structure is insufficient, while when it exceeds 50%, the hardness of the base structure is decreased. Since this tends to be undesirable, it is set at 5 to 50%.

Next, in the present invention, the fine hard particles are desirably iron-based fine hard particles containing carbide-forming elements, and the hardness must be lv200 or more.

This is because if the hardness of the fine hard particles is less than HV200, almost no contribution to the improvement of wear resistance is recognized.

Next, the size of the fine hard particles is 5 to 150 in average particle size.
μ is desirable.

This is because if the size of the fine hard particles is less than 5μ, the effect of improving wear resistance is not sufficient, and on the other hand, if the size exceeds 150μ, the fine hard particles become too coarse, increasing the damage to the sliding mating material. In addition, the fine hard particles are likely to fall off from the matrix structure, so the thickness was set at 5 to 150 μm.

Further, it is desirable that the amount of fine hard particles dispersed in the matrix structure of the Cu-Ni alloy is 10 to 70%.

This is because if the amount of dispersed fine hard particles is less than 10%, the effect of improving wear resistance will not be sufficient, and if the amount exceeds 70%, the amount of dispersed fine hard particles will be excessive and the seizure resistance will deteriorate. ~70%.

Furthermore, the density of the sintered body needs to be 90% or more of the theoretical density.

This is because pitting resistance decreases when the sintered body density is less than 90% of the theoretical density.

[Embodiment] Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

Table 1 shows the manufacturing conditions for test pieces for evaluating the properties of each of the present invention materials and comparative materials.

Table 1 Note 1) Composition (1) is 1.5%C-0, 2%Mn-12
It is a material equivalent to JIS standard 5KDII with a composition consisting of %Cr-1%Mo-0,35%V-BalFe.

Note 2) Composition (2) is 0.4%C-5%Cr-1%Mo
-O,S%P-BalFe.

Note 3) Composition (3) is 0.9%C-4,5%Cr-5%
JIS consisting of M o -6%W-2%V-BalFe
This is the composition of a material equivalent to standard 5KD9.

Note 4) Composition (4) is 0.02%C-1,1%Cr-
JIS standard SC consisting of 0゜3%Mn-Ba1Fe
This material is made with r.゛The present invention material (■) has fine hard particles dispersed in the matrix structure of a copper-based sintered alloy of 1.5%C-0.2%Mn-12%C.
As a commercially available alloy powder having a composition equivalent to JIS standard 5KDII with a composition consisting of r-1% Mo-0, 35% V-BalFg, 15% by weight of these fine hard particles was added to electrolytic copper powder and electrolytic copper powder. 10% by weight of Ni powder and zinc stearate powder as a lubricant were mixed for 30 minutes in a ■ type mixer.

The mixed powder raw material for powder metallurgy produced as described above was compacted with a pressure of 4 ton/cm 2 using a powder compacting die.

Next, this compacted compact was heated and sintered at 1000° C. for 30 minutes in an ammonia decomposition gas atmosphere to produce a test piece of the material (1) of the present invention.

The fine hard particles used had a hardness of 390° Hv and an average particle diameter of 72 μm.

Next, the present invention material (1) was prepared using the same conditions as the present invention material (2), except that the amount of fine hard particles dispersed in the base structure of the copper-based sintered alloy was set at 40% by weight. A test piece (①) was manufactured.

Next, the present invention material (2) was prepared under the same conditions as the present invention material (2), except that the amount of fine hard particles dispersed in the base structure of the copper-based sintered alloy was 65% by weight. A test piece of the invention material (■) was manufactured.

Next, the present invention material (1) was made under the same conditions as the present invention material (2), except that the average particle diameter of the fine hard particles dispersed in the base structure of the copper-based sintered alloy was 30 μm. A test piece of the invention material (1) was prepared.

Next, the present invention material (1) was prepared under the same conditions as the present invention material (2), except that the average particle diameter of the fine hard particles dispersed in the base structure of the copper-based sintered alloy was 140 μm. Invented material■
A test piece was manufactured.

Next, the present invention material (1) has a Cu-based sintered alloy base structure.
A test piece of the invention material (2) was prepared using a 45% by weight Ni-based alloy, and other conditions were basically the same as those of the invention material (1).

Next, the present invention material
A test piece of the invention material (2) was prepared using a sprayed powder having a composition of o -0.5% P-BalFg, and other conditions were basically the same as those of the invention material (1).

The average particle size of the fine hard particles is 60μ, and the hardness is Hv2.
60.

Next, the present invention material
JI consisting of %Mo-6%W-2%V-BalFe
A test piece of the invention material (2) was prepared using an atomized powder having a composition equivalent to S standard 5KD9 material, and other conditions were basically the same as those of the invention material (1).

The amount of fine hard particles dispersed was 40% by weight, the average particle size was 38μ, and the hardness was HV430.

Next, comparative material (2) was prepared by adding 0.9% C-
4,5%Cr-5%Mo-6%W-2%V-Bal
A test piece of Comparative Material (2) was prepared using a spray powder having a composition of a material equivalent to JIS standard 5KD9 consisting of Fe, and other conditions being basically the same as those of Inventive Material (2).

Note that the amount of fine hard particles dispersed is 5%.

Next, comparative material (2) was prepared by adding 0.9% C-
4,5%Cr-5%Mo-6%W-2%V-BalFe
A test piece of Comparative Material (2) was prepared using an atomized powder having a composition equivalent to JIS Standard 5KD9 material consisting of the following, and other conditions being basically the same as those of Inventive Material (2).

Note that the amount of fine hard particles dispersed is 80%.

Next, comparative material (2) was prepared by adding 0.9% C-
4,5%Cr-5%Mo-6%W-2%V-Bal
A test piece of Comparative Material (2) was prepared using a spray powder having a composition of a material equivalent to JIS standard 5KD9 consisting of Fe, and other conditions being basically the same as those of Inventive Material (2).

The amount of fine hard particles dispersed was 80%, and the average particle size was 20%.
The 5μ1 particle hardness is HV41Q.

Next, for comparison material (■), fine hard particles dispersed in the matrix structure of copper-based sintered alloy were mixed at 0.02%G -1,1%Q r
- JIS standard SC consisting of 0.3% Mn-Ba1Fe
A test piece of Comparative Material (2) was prepared using a spray powder having the composition of the R-equivalent material and other conditions being basically the same as those of Inventive Material (2).

The amount of fine hard particles dispersed was 80%, and the average particle size was 40%.
The μ1 particle hardness is HV120.

Next, comparative material ① was prepared by dispersing the alloy constituting the base structure of the copper-based sintered alloy into the base structure of the copper-based sintered alloy using copper-based alloy powder having a composition of cu-ssn. Hard particles: 1.5%C-12%Cr-1%MO-0.35%
V - JIS standard 5 consisting of 0.2% Mn-Ba1Fe
A test piece of Comparative Material (2) was prepared using a sprayed powder having the composition of a material equivalent to KDI, and other conditions being basically the same as those of Inventive Material (2).

The amount of dispersed fine hard particles is 80%, and the average particle size is 72%.
The μ2 particle hardness is HV390.

For each test piece produced as described above, the wear resistance was evaluated by the "wear scar width" using an Okoshi type abrasion tester, and the seizure resistance was evaluated by the "seizure load" using a seizure tester. Based on the occurrence of pitting in a transfer fatigue test using a Mori 2 transfer fatigue tester, the pitch-notching resistance was evaluated by "50% fracture life."

The test conditions for each test are as follows.

That is, in the Okoshi type abrasion test, the load was 18°9Kg.
, the circumferential speed of the mating material; 0.119 m/sec, the wear distance M; 160 m, the material of the mating material; "wear scar width" was measured according to JIS standard 545C.

In addition, in the seizure test, the sliding speed was 15 m/sec.
.

Load + 20 Kg/cm 2 to 20 Kg/c
Gradual increase in m” increments (test continued for 30 minutes at each load stage)
, lubricant: SAE #40 lubricating oil, mating material JIS standard 545C, roundness: 1 μ or less, 1 surface roughness: 1.2 to 2.0 μ disk, shoe test piece: Hon. Seizure load J was measured using test specimens prepared from the invention materials ■ to ■ and comparative materials ■ to ■, with surface roughness of 1.9 to 3.5μ.

Further, in the pitching test, the "50% fracture life" was measured by a rolling fatigue test using a steel ball using a Mori 2 rolling fatigue testing machine with a test load of 100 kg.

Note that the steel balls used were 3/8 inch.

The test results are shown in Table 2.

Table 2 As is clear from Table 2 above, the inventive materials ■ to ■ have a higher wear scar width in the abrasion test than the comparative materials ■ to ■.
It has excellent wear resistance because it has a small amount of friction, it has excellent seizure resistance because it has a large "seizure load" in the seizure test, and it has excellent pitting resistance because it has a large "50% fracture life" in the pitting test. It is understood that they are superior in sex.

〔Effect of the invention〕

As is clear from the above, according to the high-density copper-based sintered alloy according to the present invention, by using the Cu-Ni-based alloy as the base structure alloy, it is possible to ensure excellent seizure resistance and pitting resistance. , by dispersing an appropriate amount of fine hard particles with a specific composition into the matrix structure made of this Cu-Ni alloy, it imparts excellent wear resistance and provides excellent sliding properties even under severe usage conditions. This has the advantage that it can be suitably applied as a sliding member that has excellent wear resistance even though it is a copper-based sintered alloy.

Claims (1)

[Claims] 1. In a base structure consisting of a copper-based alloy containing Ni; 5 to 50% by weight, C; 0.2 to 3.5%, and
Cr; 0.5-25%, Mo; 0.3-7.0%, W;
0.5-25%, V; 0.2-6.0%, Co; 0.5
~18%, Ni: 0.2~3.0%, Mn: at least one type from 1.2% or less, the balance consisting of unavoidable impurities and Fe, at a weight ratio of 10~
A high-density copper-based sintered alloy characterized by 70% dispersion. 2. C; 0.2 to 3.5%, and
Cr; 0.5-25%, Mo; 0.3-7.0%, W;
0.5-25%, V; 0.2-6.0%, Co; 0.5
~18%, Ni; 0.2~3.0%, Nb; 0.05~
3.0%, B; 0.03-0.5%, P; 0.1-0.
8%, Mn: 1.2% or less, Si: 1.5% or less, the remainder being unavoidable impurities and Fe.
A high-density copper-based sintered alloy characterized in that fine hard particles consisting of the following are dispersed in a weight ratio of 10 to 70%. 3. The high-density copper-based sintered alloy according to claim 1 or 2, wherein the hardness of the fine hard particles is Hv200 or more. 4. The high-density copper-based sintered alloy according to claim 1 or 2, wherein the fine hard particles have an average particle diameter of 5 to 150 μm. 5. The high-density copper-based sintered alloy according to claim 1 or 2, wherein the sintered body density is 90% or more of the theoretical density.