JP3397333B2 - Sintered sliding member and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sintered sliding member containing iron as a main component and a method for producing the same, and more specifically, the structure of the base material exhibits pearlite or a structure in which pearlite and part of ferrite coexist. The present invention relates to an iron-based sintered sliding member in which graphite is dispersed and no free cementite is present in the structure, and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, many iron-based sintered sliding members have been proposed in which graphite is dispersed and contained in the structure by utilizing the solid lubricating action of graphite.

[0003]

However, in a sintered sliding member whose base material is iron as a main component, iron powder and graphite powder react in the sintering process and free cementite having a high hardness is present in the structure. (Fe ₃ C) is generated, and the free cementite damages the mating material when sliding with the mating material, which is a disadvantage that must be avoided as much as possible in the sliding member.

As a method for preventing the formation of free cementite, for example, a small amount of graphite (1 wt% or less) is mixed, and sintering is performed at a low temperature (1000 ° C. or less) where free cementite cannot be produced. However, the solid lubrication action of the compounded graphite cannot be expected by the above method, and the mechanical strength as a sliding member is low by the above method, and it is possible to obtain by any method. The sliding member remains a problem that it is difficult to put it to practical use.

Further, as another method, by using a so-called copper-coated graphite powder obtained by plating graphite powder with copper, it is possible to obtain an iron-based sintered sliding member in which free cementite is not formed. In the method, a step of pre-plating the graphite powder with copper is required, resulting in high cost,
It is industrially difficult to apply copper plating to all graphite particles, and as a result of the above, it is difficult to completely prevent the formation of free cementite.

[0006]

[Means for Solving the Problems] As a result of intensive studies in view of the above-mentioned problems, the present inventors have found that by blending iron powder and graphite powder with a certain proportion of aluminum powder,
Exhibiting a coexisting structure of pearlite or a part of ferrite with pearlite, which is a preferable structure as an iron-based sintered sliding member,
Moreover, not only graphite dispersed in the structure but also a sintered sliding member free from the formation of free cementite is obtained, and by further adding a certain proportion of high speed tool steel and / or carbon tool steel powder to it. The present invention has been completed by finding that the base material of the sintered body is strengthened and the wear resistance is improved.

That is, the first object of the present invention is to provide 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder,
From 10 to 30% by weight of high-speed tool steel and / or carbon tool steel powder, the balance iron powder, or 10 to 30% by weight of copper powder or 10 to 30% by weight of copper powder and 1 to 10% by weight of tin powder in addition to these component compositions. a sintered body of mixed powder comprising, matrix organization caused a pearlite structure or pearlite and some ferrite coexisting tissue, and graphite in the tissue
Not only exist in a dispersed state but also form raw cementite.
( EN) Provided is a sintered sliding member which is characterized by the absence of its formation, and a method for producing the same.

A second object of the present invention is to provide a multilayer sintered sliding member in which a sintered layer having the above-described composition is integrally bonded to a steel backing metal to form a multilayer, and a method for producing the same. It is in.

Further, the sintered sliding member of the present invention can be applied as an oil-impregnated sintered sliding member by subjecting it to an oil impregnation treatment depending on its intended use and application.

The composition of components for forming the sintered sliding member will be described below.

Graphite (Gr) is dispersed and contained in the structure and has a solid lubricating function. A compounding amount of at least 3% by weight is required to exert a solid lubricating effect. Further, since the presence of the aluminum component described later does not cause the formation of free cementite due to the reaction between the graphite and the iron component, a large amount of 8% by weight can be blended. However, if the content exceeds 8% by weight, the mechanical strength of the sliding member is impaired, so the content ratio is limited to 8% by weight. Therefore, the blending ratio of the graphite component is 3
-8% by weight, especially 4-6% by weight are suitable.

Aluminum (Al) forms a liquid phase during the sintering process to form a solid solution with the iron component, and has the function of suppressing the reaction between the iron component and the graphite by diffusing and reducing the above-mentioned graphite to the iron component. As a result, it prevents the formation of free cementite. When the blending ratio is 0.5% by weight or less, the function of inhibiting the formation of free cementite is not recognized, and when the blending ratio exceeds 5% by weight, the amount of liquid phase is increased and the sinterability is adversely affected. Exert. Therefore, the mixing ratio of the aluminum component is 0.5 to 5% by weight, especially 1.5 to 3
Weight percent is suitable.

Since high-speed tool steel (SKH) or carbon tool steel (SK) has fine intermetallic compounds and carbides present therein, they are dispersed in the sintered body and serve as a hard phase. During sintering, alloy elements diffuse from the high speed tool steel or carbon tool steel to strengthen the base (so-called dispersion strengthening), and improve the wear resistance of the sintered body. And
If the blending ratio is 10% by weight or less, the above effect is not observed, and if it is blended over 30% by weight, the hard phase is dispersed in a large amount and the wear resistance is rather deteriorated. Therefore, the blending ratio of the components of the high speed tool steel and / or the carbon tool steel is 10 to 30% by weight, preferably 15 to 25% by weight.

With respect to the above-mentioned graphite component, aluminum component and high speed tool steel and / or carbon tool steel component, a certain proportion of copper (Cu) component or copper component and tin (S)
By blending the n) component, the friction and wear characteristics of the sintered sliding member can be improved. During the sintering process, a part of the copper component diffuses and forms a solid solution with the iron component, which is the main component, and another component forms a liquid phase that acts as a binder, densifying the sintered body and strengthening it. And further enhance the hardness of the pearlite structure by densifying the pearlite structure. When the mixing ratio of the copper component is 10% by weight or less, the above-described effects are not sufficiently exhibited, and when the mixing ratio exceeds 30% by weight, the amount of the liquid phase increases and the sinterability is adversely affected. Not only does this result in a problem in the dimensional stability of the sliding member. Therefore, the blending ratio of the copper component is 10 to 30% by weight, preferably 15 to 25% by weight.

The tin component forms a liquid phase at a temperature of 232 ° C. during the sintering process, forms a solid solution with the above-mentioned copper component and alloys to form bronze, and serves as a binder and burns similarly to the above-mentioned copper component. By densifying the sintered body, it contributes to the improvement of the strength, toughness and mechanical strength of the sintered body. If the compounding ratio of the tin component is 1% by weight or less, the above-mentioned effects are not sufficiently exhibited, and if the compounding ratio exceeds 10% by weight, the sinterability is adversely affected. Therefore, the proportion of the tin component is 1 to 10% by weight, preferably 3 to 8% by weight.

Next, a method for manufacturing a sintered sliding member having the above-mentioned composition will be described.

3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder and 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder are blended with iron powder.
10 to 30% by weight of copper powder or 10 to 30% by weight of copper powder is added to the mixed powder.
30 wt% and 1-10 wt% tin powder are blended and mixed to form a mixed powder.

The high-speed tool steel powder in the above components is a high-speed tool steel powder defined in Japanese Industrial Standard (JIS) G4403, for example, Mo-based SKH51 to S.
It is recommended to use the powder of KH59, and the carbon tool steel powder is the powder of the carbon tool steel defined in Japanese Industrial Standard (JIS) G4401.

Next, the mixed powder is loaded into a mold having a required shape and compression-molded under a pressure of ^{2 to} 7 ton / cm ² to form a green compact made of the mixed powder. The green compact thus obtained is heated in a heating furnace adjusted to a neutral or reducing atmosphere at a temperature of 1050-1100 ° C. for 30-6.
Sintering for 0 minutes, then furnace cooling, removal from furnace, and machining to desired dimensions to obtain a sintered sliding member. Here, as the neutral or reducing atmosphere, ammonia decomposition gas,
Nitrogen gas, endothermic gas, etc. are used.

In the sintered sliding member thus obtained, the base structure exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, and free cementite is not formed in the structure. Further, the graphite powder and the high speed tool steel and / or the carbon tool steel powder are present dispersed in the structure, and the solid lubricating action of the graphite is sufficiently exerted in the sliding between the sintered sliding member and the mating material. In addition, the wear resistance is improved by dispersing the hard phase of the high speed tool steel and / or the carbon tool steel powder. Furthermore, this sintered sliding member can be applied as an oil-impregnated sintered sliding member by subjecting it to oil impregnation treatment according to its intended use and application. In this oil-impregnated sintered sliding member, the synergistic action of the solid lubricating action of graphite in the sintered body and the liquid lubricating action of the lubricating oil is exhibited.

Next, a method for producing a multilayer sintered sliding member will be described in which a sintered body having the above-described composition is joined to a steel backing metal as a sintered layer to form a multilayer.

The steel backing which forms this multilayer sintered sliding member is a steel plate made of rolled steel for general structure (JISG3101) or a carbon steel pipe for general structure (JISG3).
A steel pipe consisting of 444) is used.

A method of manufacturing a multilayer sintered sliding member using each steel backing metal will be described below.

<Manufacturing Method of Multi-Layer Sintered Sliding Member Using Steel Plate for Steel Back Metal> When a steel plate is used for steel back metal, it is preferable to use a powder rolling method as the manufacturing method. A manufacturing method using is explained. A mixed powder similar to the above-mentioned mixed powder is formed, and a 1 to 15 wt% aqueous solution of a powder binder is added to the mixed powder in an amount of 0.1 to 0.1% of the mixed powder.
5.0 wt% is blended and uniformly mixed to form a raw material powder which gives the mixed powder wettability.

As the powder binder, hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), methyl cellulose (MC), gelatin,
Examples include gum arabic and starch, among which H
The use of PC is preferred. As a solvent for the powder binder, water or a hydrophilic compound such as ethyl alcohol other than water may be used.
It is also possible to use an aqueous solution of up to 20% by weight. The powder binder is preferably added to the above solvent in an amount of 1 to 15% by weight to form an aqueous solution. The mixing ratio of the powder binder aqueous solution is preferably 0.1 to 5.0% by weight with respect to the mixed powder, and when the amount is more than this, uncontrollable pores (pores) in the sintered body structure increase. It reduces the strength and wear resistance of the obtained sintered layer.

The raw material powder to which the above-mentioned wettability is given is then supplied to a rolling roll by a conveyor and a hopper, and the raw material powder is formed into a rolling sheet (compacted powder sheet) by the rolling roll. A horizontal rolling mill having twin rolls is used for rolling the raw material powder. The density and thickness of the rolled sheet can be adjusted by the rolling load, while the rolling load depends on the roll speed and the roll gap. Therefore, it is possible to adjust the density and thickness of the rolled sheet by changing the roll speed and the roll interval. For example, if the roll speed is 0.1 to 1.0 m / min and the roll interval is 0.4 to 1.0 mm, the density is 5.
A rolled sheet having a thickness of 5 to 6.7 g / cm ³ and a thickness of 1.38 to 1.83 mm is obtained. The rolled sheet thus obtained is cut into a size corresponding to the size of the steel plate as the steel back metal using a cutting machine or the like, and the cut rolled sheet is superposed on the steel plate.

Then, the steel sheet and the rolled sheet laminated on the steel sheet are placed in a heating furnace adjusted to a neutral or reducing atmosphere, and the steel sheet of the rolled sheet is sintered at the same time as sintering of the rolled sheet under pressure. Diffusion / bonding is performed upward to obtain a multilayer sintered sliding member in which a sintered layer is integrally bonded on a steel plate.

In this sintering step, the pressure at the time of sintering increases the density of the sintered structure and improves the joint strength with the steel sheet. In the present invention, 1.0 to 4.0 kgf / cm ² ,
It is preferably 2.0 to 3.0 kgf / cm ² .

The sintering temperature has a sensitive influence on the sintered structure, and special attention must be paid to temperature control. In the present invention, it is performed in the range of 1050-1100 ° C. When a copper component or a copper component and a tin component are mixed in the components of the rolled sheet, a liquid phase is generated during the sintering of the rolled sheet and the sintering proceeds, and the amount of the liquid phase increases when the sintering temperature is raised. The density as a sintered body increases and increases, but with the increase of the pressure,
The liquid phase generated during sintering is discharged from the upper and lower sides to the outside of the sintered body by simple pressure, and gradually exhibits a peculiar structure with a small amount of liquid phase. Therefore, when the copper component or the copper component and the tin component are mixed in the components, the lower limit of the above temperature range is used as the sintering temperature.

The sintering time does not affect the sintered structure as sensitively as the sintering temperature, but does affect the mechanical strength of the sintered layer. In the present invention, good results are obtained when the sintering time is in the range of 30 to 60 minutes.

In the multilayer sintered sliding member thus obtained, the iron component in the components of the rolled sheet diffuses into the steel sheet at the same time as the sintering of the rolled sheet during pressure sintering and is integrally joined. The structure of the sintered layer exhibits a pearlite structure or a structure in which pearlite and some ferrite coexist, similar to the structure of the sintered sliding member described above, and free cementite is not formed in the structure. , Graphite and high speed tool steel and / or carbon tool steel particles are present dispersed in the structure.
This multi-layered sintered sliding member can be applied as an oil-impregnated multi-layered sintered sliding member by subjecting it to an oil impregnation treatment depending on the intended use and application.

<Manufacturing Method of Multi-Layer Sintered Sliding Member Using Steel Pipe for Steel Backing> A mixed powder similar to the mixed powder in the above-mentioned manufacturing method of the sintered sliding member is formed, and this mixed powder is used. In the required mold, pressure is applied under a pressure in the range of ² to 7 ton / cm ² to form a cylindrical green compact.

This cylindrical green compact was press-fitted onto the inner surface of a steel pipe and then placed in a heating furnace adjusted to a neutral or reducing atmosphere, at a temperature of 1050 to 1100 ° C. for 30 to 30 ° C.
Simultaneous sintering of the green compact for 60 minutes and diffusion bonding of the green compact to the inner surface of the steel pipe, and a sintered layer integrally bonded to the inner surface of the steel pipe. Get the members.

In this manufacturing method, when the inner diameter of the cylindrical green compact is 40 mm or more, the expansion amount (outer diameter side) of the green compact during sintering is smaller than the expansion amount of the steel pipe. The inner surface of the powder is filled with ceramic powder to restrain the expansion amount of the green compact to the inner diameter side, and this is directed to the outer diameter side, and further contraction of the green compact to the inner diameter side during cooling after sintering. By constraining the amount and directing it toward the outer diameter side, a strong joint is obtained between the steel pipe and the green compact.

The ceramic powder used in the above-mentioned method is one that does not melt within the sintering temperature range and is non-reactive with the components of the green compact in the neutral or reducing atmosphere. Anything will do. For example,
Examples thereof include Al ₂ O ₃ , SiO ₂ , ZrO ₂ and MgO, and their composite oxides.

Further, the inner diameter of the green compact is particularly large (about 7
In the case of 0 mm or more), the amount of expansion (outer diameter side) of the green compact during sintering becomes smaller than the amount of expansion of the steel pipe. By inserting the core into the inner surface of the green compact and utilizing its expansion force, a stronger joint can be obtained between the steel pipe and the green compact. As the core, one having a large coefficient of thermal expansion and durability, for example, austenitic stainless steel (coefficient of thermal expansion of about 1.5 × 10 ⁻⁵ / ° C.) is preferable.

The multi-layered sintered sliding member thus obtained has a structure in which the iron component in the components of the green compact diffuses into the steel pipe simultaneously with the sintering of the green compact during sintering. The structure of the sintered layer is joined to form multiple layers, and the structure of the sintered layer exhibits a pearlite structure or a structure in which pearlite and some ferrite coexist, similar to the structure of the sintered sliding member described above, and free cementite is formed in the structure However, graphite and high speed tool steel and / or carbon tool steel particles are present dispersed in the structure. This multi-layered sintered sliding member can be applied as an oil-impregnated multi-layered sintered sliding member by subjecting it to an oil impregnation treatment depending on the intended use and application.

[0038]

[Function] Generally, in an iron-based sintered sliding member containing a large amount of graphite in iron powder to exert a solid lubricating effect, it is inevitable that high hardness free cementite is generated in the sintered structure. By blending a certain amount of aluminum powder as in the present invention, a large amount of graphite can be contained in the structure without producing free cementite. The reason for this is not necessarily clear, but one of them is that the solid solution limit of other elements to the iron component is constant, and it has an affinity with the iron component during the sintering of the mixed powder containing the aluminum component and the graphite component. The present inventors presume that this is because the aluminum component having a high content is preferentially solid-dissolved in the iron component to reach the solid-solution limit and prevents the solid solution of the graphite component in the iron component.

The thus-obtained sintered sliding member has no formation of high hardness free cementite in the structure, contains a large amount of graphite, and is dispersed due to the dispersion of the hard phase of the high speed tool steel and / or the carbon tool steel powder. In the sliding member, which damages the mating material due to the presence of free cementite in the tissue during sliding with the mating material, the drawbacks that must be avoided as much as possible are completely eliminated, and sliding characteristics can be improved.

Further, in the sintered sliding member in which the copper component or the copper component and the tin component are blended in the components, since these components generate a liquid phase during sintering, the sintered body can be densified. Improve the strength of the sintered body. Further, in the multilayer sintered sliding member in which the sintered layer is integrally joined to the back metal, the load resistance of the sliding member is greatly improved.

[0041]

EXAMPLES Hereinafter, the sintered sliding member of the present invention will be described in detail based on its examples.

<Example 1> For the reduced iron powder passing through a 240 mesh sieve, 25
2% by weight aluminum powder passing through a 0 mesh screen and high speed tool steel (SK through a 200 mesh screen)
After mixing 15% by weight of H51) powder for 20 minutes with a V-type mixer, 5% by weight of 48-250 mesh natural graphite powder was mixed and mixed again for 5 minutes with a V-type mixer to obtain a mixed powder (Fe: 78%, Al: 2%, high speed tool steel:
15%, graphite: 5%).

Then, this mixed powder was loaded into a mold,
18 mm inner diameter, 25 m outer diameter at a molding pressure of 3 ton / cm ^2.
A cylindrical green compact having a length of m and a length of 18 mm was obtained. This cylindrical green compact was placed in a heating furnace adjusted to an ammonia decomposition gas atmosphere and sintered at a temperature of 1100 ° C. for 60 minutes,
A sintered sliding member was obtained by machining into desired dimensions. The density of this sintered sliding member was 5.00 g / cm ³ , the structure exhibited a pearlite structure, no free cementite was formed in the structure, and graphite and high-speed tool steel particles were present in a dispersed state. . The sintered sliding member was subjected to oil impregnation treatment to obtain an oil impregnated sintered sliding member having an oil content of 26% by volume.

<Example 2> For the reduced iron powder passing through a 240 mesh sieve, 25
2% by weight of aluminum powder passing through a 0 mesh sieve,
High speed tool steel (SKH5
1) 15% by weight of powder, 20% by weight of electrolytic copper powder passing through a 150-mesh sieve, and 3.3% by weight of atomized tin powder passing through a 250-mesh sieve were mixed and mixed for 20 minutes with a V-type mixer. , 5% by weight of 48-250 mesh natural graphite powder, and again with V mixer.
Mixing for a minute to obtain a mixed powder (Fe: 54.7%, A
1: 2%, high speed tool steel: 15%, Cu: 20%, S
n: 3.3%, graphite: 5%).

Then, the mixed powder was loaded into a mold,
18 mm inner diameter, 25 m outer diameter at a molding pressure of 3 ton / cm ^2.
A cylindrical green compact having a length of m and a length of 18 mm was obtained. This cylindrical green compact is placed in a heating furnace adjusted to an ammonia decomposition gas atmosphere and sintered at a temperature of 1050 ° C. for 30 minutes,
A sintered sliding member was obtained by machining into desired dimensions. The density of this sintered sliding member was 5.20 g / cm ³ .

It was confirmed that the structure of this sintered sliding member had a pearlite structure and no free cementite was formed in the structure, and that graphite and high speed tool steel particles were dispersed in the structure. It was Then, the sintered sliding member was subjected to an oil impregnation treatment to obtain an oil impregnated sintered sliding member having an oil content of 24% by volume.

Example 3 The same mixed powder as in Example 2 was obtained (Fe: 54.7).
%, Al: 2%, high speed tool steel: 15%, Cu: 20
%, Sn: 3.3%, graphite: 5%).

5% by weight of a hydroxypropylcellulose (HPC) aqueous solution (HPC 100 g, ethyl alcohol 120 ml and water 1780 ml) was added to the mixed powder in an amount of 0.5% based on the mixed powder weight, and the mixture was mixed with a V-type mixer 5
The materials were uniformly mixed for a minute to obtain a raw material powder having wettability.

The raw material powder was passed through a horizontal rolling roll having a twin roll having a diameter of 603 mm under the conditions of a roll interval of 0.7 mm and a roll speed of 0.3 m / min, and a density of 6.25 g.
A rolled sheet (compacted powder sheet) having a thickness of 1 / cm ³ and a thickness of 1.48 mm was formed. Width 170mm, length 60
Cut it to 0 mm, put two pieces on a steel plate of 170 mm in width, 600 mm in length, and 5 mm in thickness for rolled steel for general structure (JISG3101), place it in a heating furnace adjusted to an atmosphere of ammonia decomposition gas, and heat it to a temperature of 1050 ° C. For 30 minutes,
After applying the pressure of 3.0 kgf / cm ² , the rolled sheet was sintered and simultaneously diffused and joined with the steel sheet, and then machined to a desired size, and the sintered layer was integrally joined on the steel sheet. A sintered sliding member composed of multiple layers was obtained. The density of the sintered layer of this sintered sliding member is 5.40 g / cm ³ ,
The joint strength between the steel plate and the sintered layer is 530 kg / cm ^2.
Met.

The structure of the sintered layer of this multilayer sintered sliding member exhibits a pearlite structure, no free cementite is formed in the structure, and graphite and high speed tool steel particles are present dispersed in the structure. Was confirmed. Then, the sintered sliding member was subjected to an oil impregnation treatment to obtain an oil impregnated sintered sliding member having an oil content of 18% by volume.

Example 4 The same mixed powder as in Example 2 was obtained (Fe: 54.7).
%, Al: 2%, high speed tool steel: 15%, Cu: 20
%, Sn: 3.3%, graphite: 5%).

This mixed powder was loaded into a mold and subjected to a molding pressure of 3 ton / cm ² to have an inner diameter of 18 mm, an outer diameter of 24 mm and a length of 3.
A 0 mm cylindrical green compact was obtained. Separately prepared, this cylindrical green compact has an inner diameter of 24 mm, an outer diameter of 34 mm, and a length of 3
General structural carbon steel pipe with a size of 0 mm (JISG
3444) made by press fitting to the inner diameter surface of the steel pipe,
This is placed in a heating furnace adjusted to an ammonia decomposing gas atmosphere, sintered at a temperature of 1070 ° C. for 30 minutes, and simultaneously with the sintering of the cylindrical green compact, diffusion / bonding with the inner diameter surface of the steel pipe is performed. After tightening, it was machined to a desired size to obtain a sintered sliding member composed of multiple layers. The density of the sintered layer of this sintered sliding member was 5.20 g / cm ³ , and the bonding strength between the steel pipe and the sintered layer was 486 kg / cm ² .

The structure of the sintered layer of this multilayer sintered sliding member exhibits a pearlite structure, no free cementite is formed in the structure, and graphite and high-speed steel particles are dispersed in the structure. Was confirmed. Then, the sintered sliding member was subjected to an oil impregnation treatment to obtain an oil impregnated sintered sliding member having an oil content of 24% by volume.

<Example 5> The same mixed powder as in Example 2 was obtained (Fe: 54.7).
%, Al: 2%, high speed tool steel: 15%, Cu: 20
%, Sn: 3.3%, graphite: 5%).

This mixed powder was loaded into a mold, and at a molding pressure of 3 ton / cm ² , an inner diameter of 42.5 mm and an outer diameter of 48.5 m.
A cylindrical green compact having a length of m and a length of 25 mm was obtained. Separately prepared, this cylindrical green compact has an inner diameter of 48.5 mm and an outer diameter of 55 m.
Two steel pipes each having a size of m and a length of 50 mm were press-fitted in the inner diameter surface of the steel pipe in the axial direction.

A ceramic pipe (Al powder) is formed on the inner diameter surface of the green compact of a steel pipe in which a cylindrical green compact is press fitted into the inner diameter surface.
A mixture of ₂ O ₃ : 83% by weight and SiO ₂ : 17% by weight,
(35-150 mesh) and then placed in a heating furnace adjusted to an ammonia decomposition gas atmosphere and sintered at a temperature of 1050 ° C. for 30 minutes, and at the same time as the sintering of the cylindrical green compact, the inner diameter of the steel pipe After diffusion and bonding with the surface,
By machining to a desired size, a sintered sliding member composed of multiple layers was obtained. The density of the sintered layer of this sintered sliding member was 5.20 g / cm ³ , and the bonding strength between the steel pipe and the sintered layer was 486 kg / cm ² .

The structure of the sintered layer of this multilayer sintered sliding member exhibited a pearlite structure, no free cementite was formed in the structure, and graphite and high speed tool steel particles were present dispersed in the structure. Was confirmed. Then, the sintered sliding member was subjected to an oil impregnation treatment to obtain an oil impregnated sintered sliding member having an oil content of 24% by volume.

In addition, in the above-mentioned embodiment, an example in which the high speed tool steel powder is used is shown. However, instead of the high speed tool steel powder, carbon tool steel powder is used alone, or the high speed tool steel powder and carbon are used. Tool steel powder can be compounded and used at the same time.

Next, the sliding characteristics of the sintered sliding member obtained in each of the above-mentioned examples will be described with respect to the results of testing under the following test conditions.

-Sintered sliding members of Examples 1 and 2
Test conditions for   An endurance test   Friction speed 5m / min   Load 20 kgf / cm^Two   Stroke 200 mm   Test stroke 100,000 cycles (160 mm / cycle)   Sliding distance 40,000m   Counterpart material Carbon steel for machine structure (S45C)   Testing machine Linear reciprocating motion testing machine

Test strip for the sintered sliding member of Example 3
Case-   An endurance test   Friction speed 7m / min   Load 120kgf / cm^Two   Stroke 80 mm   Test stroke 100,000 cycles (160 mm / cycle)   Sliding distance 16,000m   Counterpart material Carbon steel for machine structure (S45C)   Testing machine Reciprocating plane testing machine

-Sintered sliding members of Examples 4 and 5
Test conditions for   An endurance test   Friction speed 40m / min   Load 10 kgf / cm^Two   Stroke 200 mm   Test stroke 100,000 cycles (400 mm / cycle)   Sliding distance 40,000m   Counterpart material Carbon steel for machine structure (S45C)   Testing machine Linear reciprocating motion testing machine

In the above durability test, the friction coefficient and wear amount of each sintered sliding member were measured. The results are shown in Table 1. The comparative examples in Table 1 are Japanese Industrial Standards (JI
The result of having used the iron-carbon-copper system oil-containing sintered material (SMF4 type) prescribed | regulated to Z2550 of S) by the test conditions of the said Example 1 and Example 2 is shown. (Below margin)

[0064]

[Table 1]

From the test results shown in Table 1, the sintered sliding member of the present invention showed a slightly high coefficient of friction immediately after the start of the test, but gradually decreased with the progress of the test and remained stable. Particularly, as can be seen from the comparison with the comparative example, the oil-impregnated sintered sliding member was significantly improved in both the friction coefficient and the wear amount.

Observation of the surface of the mating material after the test revealed that a thin coating of graphite was formed on the mating material surface and no damage was observed.

From the above test results, the sintered sliding member of the present invention is a sliding member made of the simple substance of Example 1 and Example 2, and a sintered sliding member made of the multi-layer of Examples 3 to 5. It is applicable to a wide range of uses of moving members and sliding members thereof.

[0068]

EFFECTS OF THE INVENTION The sintered sliding member of the present invention has no formation of high hardness free cementite in the structure, and therefore, in sliding with the mating member, which is an extremely important factor in the sliding member,
It has the effect of not damaging the surface of the mating material.

Further, since the hard phase composed of high speed tool steel and / or carbon tool steel particles is dispersed and present in the sintered sliding member, the strength of the base material of the sintered body is increased and the wear resistance is improved. Can be improved.

Furthermore, since it becomes possible to form a multilayer by integrally joining the sintered layer to the steel backing metal, the range of application as a sliding member is greatly increased.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B32B 15/01 B32B 15/01 Z C22C 33/02 C22C 33/02 B 38/06 38/06

Claims (12)

(57) [Claims] 1. A sintered body of a mixed powder comprising 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder, and the balance iron powder. a is, the matrix of the tissue caused a pearlite structure or pearlite and some ferrite coexisting tissue, and
Not only graphite is dispersed in the tissue but also free
Sintered sliding member characterized by no generation of ferrite . 2. A mixed powder composed of 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder, and the balance iron powder is sintered. , matrix organization caused a pearlite structure or pearlite and some ferrite coexisting tissue and into the tissue
Not only graphite is dispersed but also free cementite
A sintered sliding member, characterized in that a sintered layer that does not generate is integrally joined to a steel back metal. 3. The mixed powder is 10 to 30% by weight of copper powder.
The sintered sliding member according to claim 1 or 2, wherein the sintered sliding member is blended in a ratio of. 4. The sintered sliding member according to claim 3, wherein the mixed powder contains tin powder in an amount of 1 to 10% by weight. 5. The sintered sliding member according to claim 2, wherein the steel backing is made of a steel plate, and the sintered layer is integrally bonded to the surface of the steel plate. 6. The sintered slide according to claim 2, wherein the steel backing is made of a steel pipe, and the sintered layer is integrally joined to the inner peripheral surface of the steel pipe. Moving member. 7. A mixed powder comprising 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder, and the balance iron powder. After forming the mixed powder into a required shape to form a green compact, the green compact is heated in a heating furnace adjusted to a neutral or reducing atmosphere at a temperature of 1050 to 1100 ° C. for 30 to 30 ° C. After sintering for 60 minutes, the matrix structure exhibits a pearlite structure or a coexisting structure of pearlite and some ferrite.
And not only is graphite dispersed in the structure,
A method for producing a sintered sliding member, which comprises obtaining a sintered body in which free cementite is not formed . 8. A mixed powder comprising 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder, and the balance iron powder. And a 1 to 15 wt% aqueous solution of a powder binder selected from hydroxypropyl cellulose, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, gelatin, gum arabic, and starch is added to the mixed powder in an amount of 0.1 to 0.1% based on the mixed powder. 5.0 wt% was added and uniformly mixed to obtain a raw material powder, the raw material powder was supplied to a rolling roll to form a rolled sheet, and the rolled sheet was superposed on a steel backing made of a steel plate. 1050 in a heating furnace adjusted to a neutral or reducing atmosphere
Sintered at a temperature of ~ 1100 ° C under a pressure of 1.0-4.0 kgf / cm ² for 30-60 minutes to simultaneously perform the sintering of the rolled sheet and the diffusion bonding to the steel backing, and the structure of the base material field but which caused a pearlite structure or pearlite and some ferrite coexisting tissue, and graphite are present dispersed in the tissue
A method for producing a sintered sliding member, characterized in that a sintered layer free from the formation of free cementite is integrally bonded to the surface of a steel backing metal. 9. A mixed powder comprising 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, 10 to 30% by weight of high speed tool steel and / or carbon tool steel powder, and the balance iron powder. To form a cylindrical green compact by pressure molding the mixed powder, and press-fitting the green compact into the inner surface of a steel backing made of a steel pipe, and setting this to a neutral or reducing atmosphere. 30 at a temperature of 1050-1100 ° C in the adjusted heating furnace
Sintering for -60 minutes, sintering of the green compact and diffusion bonding to the steel pipe are simultaneously performed, and the structure of the base material exhibits a pearlite structure or a coexisting structure of pearlite and part of ferrite.
And not only is graphite dispersed in the structure,
A method for producing a sintered sliding member, characterized in that a sintered layer without generation of free cementite is joined and integrated with an inner surface of a steel pipe. 10. The method for producing a sintered sliding member according to claim 7, wherein the mixed powder contains 10 to 30% by weight of copper powder. 11. The mixed powder is 1 to 10% by weight of tin powder.
The method for producing a sintered sliding member according to claim 10, wherein the sintered sliding member is mixed in the ratio of. 12. The inner surface of a steel backing made of a steel pipe is press-fitted with a green compact, and then the inner surface of the green compact is filled with a ceramic powder, and the inner diameter of the green compact during sintering of the green compact with the ceramic powder. The amount of expansion toward the inner side and the amount of contraction toward the inner diameter side during cooling after sintering are restricted, and by directing the amount of expansion and contraction toward the outer diameter side, a high contact pressure is generated on the inner surface of the steel pipe. The contact pressure causes diffusion of a powder compact component on the inner surface of the steel pipe, whereby the sintered layer is joined and integrated with the inner surface of the steel pipe. The method for manufacturing a sintered sliding member according to any one of 1.