JP3397332B2 - 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,
Sintered sliding that exhibits a pearlite structure, which is a preferable structure for iron-based sintered sliding members, or a structure in which pearlite and some ferrite coexist, and that graphite is dispersed in the structure and that free cementite is not formed. The inventors have found that a member can be obtained and have completed the present invention.

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,
A sintered body of mixed powder and the balance iron powder, exist matrix organization caused a pearlite structure or pearlite and some ferrite coexisting tissue and by graphite dispersed in the tissue
It is another object of the present invention to provide a sintered sliding member characterized by not only the formation of free cementite but also 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 preventing the formation of free cementite is not recognized, and when the blending ratio exceeds 5% by weight, the amount of the liquid phase increases 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% by weight.
Is appropriate.

A fixed proportion of copper (Cu) component or copper component and tin (Sn) component can be added to the above-mentioned graphite component and aluminum component. 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. And the mixing ratio of the copper component is 1
If the content is 0% by weight or less, the above-mentioned effects are not sufficiently exhibited, and if the content is more than 30% by weight, the amount of the liquid phase increases, which not only adversely affects the sinterability but also the dimension of the sliding member. This results in stability problems. Therefore,
The mixing ratio of the copper component is 10 to 30% by weight, especially 15 to 25
Weight percent is suitable.

The tin component produces a liquid phase from 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 also functions 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 of manufacturing a sintered sliding member having the above-mentioned composition will be described.

3 to 8% by weight of graphite powder and 0.5 to 5% by weight of aluminum powder are mixed with iron powder and mixed to form a mixed powder, or 10 to 30 copper powder is further added to the mixed powder. % By weight or 10 to 30% by weight of copper powder and 1 to 10% by weight of tin powder are mixed and mixed to form a mixed powder.

Then, 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 is dispersed and present in the structure, and the solid lubricating action of the graphite is sufficiently exerted when the sintered sliding member and the mating material slide with each other. further,
This sintered sliding member can be applied as an oil-impregnated sintered sliding member after being subjected to an 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 of manufacturing a multi-layer sintered sliding member will be described in which a sintered body having the above-described component composition is integrally bonded 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.

The method for producing a multilayer sintered sliding member using each steel backing 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 1 to 15 wt% aqueous solution of a powder binder is added to this mixed powder in an amount of 0.1 to 5.0 wt% and mixed uniformly. A raw material powder is formed by imparting wettability to the mixed powder.

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 rolled 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 superposed 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 during 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 1.5 to 3.0 kgf / cm ² .

The sintering temperature has a sensitive influence on the sintered structure, and it is necessary to pay particular attention 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 multi-layer 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 is dispersed in the tissue. 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 a 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-layer sintered sliding member thus obtained has the iron component in the components of the green compact diffused into the steel pipe simultaneously with the sintering of the green compact during sintering. The structure of the sintered layer, which is bonded and made into multiple layers, 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 the formation of free cementite in the structure. Rather, graphite is present dispersed in the tissue.
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.

[0036]

In general, in an iron-based sintered sliding member containing a large amount of graphite in iron powder to exert a solid lubricating action, it is inevitable that high hardness free cementite is formed 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 sintered sliding member thus obtained does not generate free cementite of high hardness in the structure and contains a large amount of graphite, and the presence of free cementite in the structure when sliding with the mating material. The drawbacks that must be avoided as much as possible in the sliding member that damages the mating material due to the above are completely eliminated.

Further, in a sintered sliding member in which a copper component or a copper component and a tin component are mixed in the components, these components generate a liquid phase during sintering, so that 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.

[0039]

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

<Example 1> For reduced iron powder passing through a 240 mesh sieve, 25
After mixing 2% by weight of aluminum powder passing through a 0-mesh sieve with a V-type mixer for 20 minutes, 5% by weight of 48-250 mesh natural graphite powder was mixed and mixed again with the V-type mixer for 5 minutes to obtain a mixed powder. Was obtained (Fe: 93%,
Al: 2%, 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 5.01 g / cm ³ , the structure exhibited a pearlite structure, no free cementite was generated in the structure, and graphite 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 25% 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,
20% by weight of electrolytic copper powder that passes through a 150 mesh screen
And 3.3 wt% of atomized tin powder that passes through a 250-mesh sieve and mixed for 20 minutes with a V-type mixer, then blended with 5 wt% of 48-250 mesh natural graphite powder and again with a V-type mixer. After mixing for 5 minutes, a mixed powder was obtained (Fe: 69.7%, Al: 2%, Cu: 20).
%, Sn: 3.3%, 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 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 5.27 g / cm ³ .

As shown in the photomicrograph of FIG. 1 (magnification 170 times), the structure of this sintered sliding member has a pearlite structure in the base material and no free cementite is formed in the structure, and graphite A is present in the structure. It was confirmed that they exist dispersedly. In addition, the code | symbol B in a figure is a copper tin alloy. 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 23% by volume.

<Example 3> The same mixed powder as in Example 2 was obtained (Fe: 69.7).
%, Al: 2%, 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% with respect to 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
It is cut into 0 mm, two pieces are superposed on a steel plate of a general structural rolled steel material (JISG3101) having a width of 170 mm, a length of 600 mm and a thickness of 5 mm, and the temperature is 1050 ° C. for 30 minutes.
Place in a heating furnace adjusted to ammonia decomposition gas atmosphere,
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 5.47 g / cm ³ ,
The joint strength between the steel plate and the sintered layer is 570 kg / cm ^2.
Met.

It was confirmed that the structure of the sintered layer of this multilayer sintered sliding member had a pearlite structure, no free cementite was formed in the structure, and graphite was dispersed in the structure. . 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 21% by volume.

Example 4 A mixed powder similar to that in Example 2 was obtained (Fe: 69.7).
%, Al: 2%, 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 1050 ° 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 5.30 g / cm ³ , and the bonding strength between the steel pipe and the sintered layer was 550 kg / cm ² .

It was confirmed that the structure of the sintered layer of this multi-layer sintered sliding member had a pearlite structure, no free cementite was formed in the structure, and graphite was dispersed in the structure. . 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 23% by volume.

<Example 5> The same mixed powder as in Example 2 was obtained (Fe: 69.7).
%, Al: 2%, 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.

On the inner surface of the green compact of the steel pipe in which the cylindrical green compact is press-fitted and fitted, the ceramic powder (Al
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 5.30 g / cm ³ , and the bonding strength between the steel pipe and the sintered layer was 550 kg / cm ² .

It was confirmed that the structure of the sintered layer of the multi-layered sintered sliding member had a pearlite structure, no free cementite was formed in the structure, and graphite was dispersed in the structure. . 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 23% by volume.

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 (400 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 the 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)

[0061]

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

From the above test results, the sintered sliding member of the present invention is the sliding member made of the simple substance of Examples 1 and 2, and the 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.

[0065]

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 sintered layer can be integrally laminated to the steel back metal to form a multilayer structure, the range of application as a sliding member is greatly increased.

[Brief description of drawings]

FIG. 1 is a micrograph (magnification 170 times) showing a sintered structure of a sintered sliding member of the present invention.

─────────────────────────────────────────────────── ─── 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 consisting of 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, and the balance iron powder, wherein the base structure is a pearlite structure or pearlite and part ferrite. coexistence tissue coloration the and tissue
Graphite not only exists in dispersed form but also free cementite
A sintered sliding member, which is characterized in that it does not generate rust. 2. A mixed powder consisting of 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, and the balance of iron powder is sintered, and the base structure is a pearlite structure or a coexisting structure of pearlite and a part of ferrite. It caused a a, and graphite in the structure
Formation of free cementite as well as dispersed
A sintered sliding member, characterized in that a non- sintered sintered layer is integrally bonded to a steel backing. 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, and a balance of iron powder is formed, and the mixed powder is molded into a required shape to obtain a green compact. After forming the body, 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 3 hours.
And sintered 0-60 minutes, 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
A method for producing a sintered sliding member, characterized in that a sintered body free from the formation of ferrite is obtained. 8. A mixed powder consisting of 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, and the balance iron powder is formed, and hydroxypropyl cellulose, polyvinyl alcohol, carboxymethyl cellulose is added to this mixed powder. 0.1 to 5.0% by weight of a powder binder selected from methyl cellulose, gelatin, gum arabic, and starch is added to the mixed powder in an amount of 0.1 to 5.0% by weight, and the mixture is uniformly mixed to obtain a raw material powder. The raw material powder is supplied to a rolling roll to form a rolled sheet, the rolled sheet is superposed on a steel backing made of a steel sheet, and the heated sheet is heated at a temperature of 1050 to 110 in a heating furnace adjusted to a neutral or reducing atmosphere.
Sintering is performed at a temperature of 0 ° C. under a pressure of 1.0 to 4.0 kgf / cm ² for 30 to 60 minutes to simultaneously perform the sintering of the rolled sheet and the diffusion bonding to the steel backing so that the base structure is the pearlite structure or pearlite and some ferrite coexisting tissue <br/> caused a, and it only graphite is 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 composed of 3 to 8% by weight of graphite powder, 0.5 to 5% by weight of aluminum powder, and the balance iron powder is formed, and the mixed powder is pressure-molded to form a cylindrical compact. A powder is produced, the green compact is pressed into the inner surface of a steel backing made of a steel pipe, and this is heated in a heating furnace adjusted to a neutral or reducing atmosphere at a temperature of 1050 to 1100 ° C. for 30 to 60 minutes. sintered, tighten perform diffusion bonding to sintered and steel pipe made of piezoelectric powder simultaneously, matrix organization caused a pearlite structure or pearlite and some ferrite coexisting tissue, and a set
Not only graphite is dispersed in the weave but also free semen
A method for producing a sintered sliding member, characterized in that a sintered layer without generation of tightness 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.