JP2012162771A - Iron-based sintered sliding member, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Fe based sintered sliding member excellent in abrasion resistance and load bearing resistance.SOLUTION: The Fe based sintered sliding member is composed of an Fe powder, a Cu-Fe-Mn alloy powder, a Co-Mo-Cr-Si superalloy powder, and a C powder. The Fe based sintered sliding member coontains Cu component of 4.45-18.6 mass%, Mn component of 0.2-1.2 mass%, Co component of 3.1-9.3 mass%, Mo component of 1.4-4.2 mass%, Cr component of 0.4-1.2 mass%, Si component of 0.1-0.3 mass%, C component of 1.0-5.0 mass% and the balance of Fe component. The base structure has a pearlite structure or a structure where pearlite and partial ferrite are coexistence and C component, Cu-Fe-Mn alloy, Co-Mo-Cr-Si superalloy are dispersedly contained in the base structure.

Description

  The present invention relates to an iron-based sintered sliding member having excellent sliding characteristics and load resistance and a method for producing the same.

Conventionally, as an iron-based sintered sliding member, a Fe-C (carbon) -based or Fe-Cu-C-based bearing material impregnated with a lubricating oil is known, and an Fe-C-based or Fe-Cu-- C-based sintered materials (for example, see Non-Patent Document 1) are known. In the conventional iron-based sintered sliding member, a blending amount of at least 3% by mass or more is required in order to obtain a solid lubricating action of C, but Fe powder and C powder react during the sintering process. A phenomenon that high hardness free cementite (Fe ₃ C) precipitates in the sintered structure appears. This precipitation of hard cementite in the structure causes the disadvantage of damaging the shaft (partner material) when sliding against the other material, for example, the shaft, and should be avoided as much as possible in sliding applications. It is an important element that must be.

JP 55-38930 A JP 58-19403 A JP 58-126959 A

Japanese Industrial Standard JISZ550

As a method for preventing the precipitation of free cementite, (1) the amount of C (graphite) is small, for example, 0.82% by mass or less, and (2) a low temperature at which free cementite does not precipitate, for example, 1000 ° C. By sintering at the following temperatures, a temporary solution can be achieved, but the method of (1) above cannot be expected to provide a solid lubricating action of the blended C, and (2
) Is not enough to form a sintered alloy, the mechanical strength of the sintered material is low, and it is difficult to apply it to sliding applications. The problem that the lubricating action cannot be sufficiently exhibited remains.

  As another method, a method of blending a graphitization stabilizing element such as Si to prevent the precipitation of free cementite (for example, see Patent Document 1) can be considered. The conditions for diffusing and dissolving Si in Fe are about Since heating at a temperature of 1200 ° C. is required, a temperature much higher than the sintering temperature of a normal Fe-based sintered material is required, which increases the manufacturing cost and severely restricts the sintering atmosphere. If not controlled, Si may be oxidized. In addition, there is a method for producing an Fe-based sintered material in which ferrosilicon (FeSi) powder is blended to prevent the precipitation of free cementite in the structure (for example, Patent Document 2 and Patent Document 3).

  In view of the above situation, the present inventor first focused on Cu and Mn, which are elements that promote the formation of a ferrite phase (α-phase) structure in Japanese Patent Application No. 2009-190176 (hereinafter referred to as prior art), and Cu Consists of 2.67 to 18.60% by mass of component, 0.12 to 1.20% by mass of Mn component, 1.0 to 5.0% by mass of C component, and remaining Fe component. An Fe-based sintered sliding member was proposed in which a structure coexisting with ferrite was present, free cementite was not precipitated in the base structure, and a Cu—Fe—Mn alloy was dispersed and contained.

This prior art Fe-based sintered sliding member has no precipitation of free cementite in the structure. For example, under a thrust test condition with a speed of 1.3 m / min, a load of 800 kgf / cm ² and a test time of 8 hours, The friction coefficient was 0.1, and the wear amount was 7 μm or less, and it exhibited excellent sliding characteristics. For example, the Fe-based sintered sliding member itself is required to have a load resistance exceeding, for example, a surface pressure of 800 kgf / cm ² and an improvement in wear resistance.

  As a result of intensive studies to satisfy the above requirements, the present inventors have found that the prior art Cu component is 2.67 to 18.60 mass%, the Mn component is 0.12 to 1.20 mass%, and the C component is 1.0 to 5. The present inventors have found that an Fe-based sintered sliding member exhibiting performance satisfying the above requirements can be obtained by further blending a certain proportion of a hard alloy with a component composition composed of 0% by mass and the balance Fe component.

  The present invention has been made on the basis of the above knowledge, and an object thereof is to provide an Fe-based sintered sliding member having excellent wear resistance and load resistance.

  The Fe-based sintered sliding member of the present invention is an Fe-based sintered sliding member composed of Fe powder, Cu-Fe-Mn alloy powder, Co-Mo-Cr-Si superalloy powder, and C powder, Cu component 4.45 to 18.6% by mass, Mn component 0.2 to 1.2% by mass, Co component 3.1 to 9.3% by mass, Mo component 1.4 to 4.2% by mass, Cr component It consists of 0.4 to 1.2% by mass, Si component 0.1 to 0.3% by mass, C component 1.0 to 5.0% by mass, and the remaining Fe component. In addition to presenting a structure in which part ferrite coexists, a C component, a Cu—Fe—Mn alloy, and a Co—Mo—Cr—Si superalloy are dispersed in the structure of the base.

  In the Fe-based sintered sliding member of the present invention, the Cu-Fe-Mn alloy dispersed and contained in the base pearlite structure or the structure in which pearlite and a part of ferrite coexist are dispersed in the form of a network at the grain boundaries of the base structure. And may be deposited.

  In the Fe-based sintered sliding member of the present invention, the Co-Mo-Cr-Si superalloy is dispersed and contained as hard particles in the base pearlite structure or the structure in which pearlite and a part of ferrite coexist. Improves load resistance and wear resistance of the moving member.

In the Fe-based sintered sliding member, the pearlite structure of the substrate or the micro Vickers hardness (HMV) of the structure in which pearlite and a part of ferrite coexist are 350 to 450. The micro-Vickers hardness of the Cu—Fe—Mn alloy dispersed and contained in the ferrite coexisting structure is 100 to 120, and the Co—Mo dispersed and contained in the base pearlite structure or the pearlite and partially ferrite coexisting structure. The micro-Vickers hardness of the —Cr—Si superalloy is 540 to 770.

According to the Fe-based sintered sliding member of the present invention, a Cu-Fe-Mn alloy having a hardness lower than the hardness of the structure is dispersed and contained in the base pearlite structure or a structure in which pearlite and a part of ferrite coexist. In addition, since the Co—Mo—Cr—Si superalloy having a hardness higher than the hardness of the structure is dispersed in the structure, the compatibility with the counterpart material such as the rotating shaft on the sliding surface is improved. The load resistance and wear resistance can be improved.

In the Fe-based sintered sliding member of the present invention, natural graphite or artificial graphite is preferably used as the C component.

In the Fe-based sintered sliding member of the present invention, lubricating oil is contained at a rate of 10 to 15% by volume.

The manufacturing method of the Fe-type sintered sliding member of the present invention is a Cu—Fe—Mn alloy powder of 5 to 20 consisting of 4 to 6 mass% of Mn, 3 to 5 mass% of Fe and the balance Cu with respect to the Fe powder as a main component. Co-Mo-Cr-Si superalloy powder consisting of 5 mass%, Co62 mass%, Mo28 mass%, Cr8 mass%, Si2 mass%, and C powder 1.0-5.0 mass% After mixing and mixing to form a mixed powder, the mixed powder is loaded into a mold to form a green compact of a desired shape, and the green compact is heated to a neutral or reducing atmosphere. It is characterized by sintering in a furnace at a temperature of 1000 to 1150 ° C. for 30 to 90 minutes.

The Fe-based sintered sliding member obtained by this manufacturing method has a Cu component of 4.45 to 18.6% by mass, a Mn component of 0.2 to 1.2% by mass, and a Co component of 3.1 to 9.3% by mass. %, Mo component 1.4-4.2% by mass, Cr component 0.4-1.2% by mass, Si component 0.1-0.3% by mass, C component 1.0-5.0% by mass, It consists of the remaining Fe component, and the base structure exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, and in the base structure, a C component, a Cu-Fe-Mn alloy, and a Co-Mo-Cr-Si super An alloy is dispersedly contained.

In the method for producing an Fe-based sintered sliding member, the Cu—Fe—Mn alloy powder in the component is preferably an alloy powder comprising 4 to 6% by mass of Mn, 3 to 5% by mass of Fe, and the balance Cu. Since this Cu—Fe—Mn alloy powder generates a liquid phase at a temperature of 1050 ° C., sintering at a temperature of 1000 ° C. or higher and lower than 1050 ° C. results in solid phase sintering, while a temperature of 1050 ° C. or higher and 1150 ° C. or lower. Sintering at this time is liquid phase sintering. In the Fe-based sintered sliding member obtained by solid phase sintering, the base exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, and there is no precipitation of free cementite in the structure, and there is no Cu in the base structure. -Fe-Mn alloy is dispersedly contained.

On the other hand, the Fe-based sintered sliding member obtained by liquid phase sintering exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, and there is no precipitation of free cementite in the structure. The Cu-Fe-Mn alloy is dispersed and contained in the form of a network at grain boundaries of the structure of the substrate.

The Fe-based sintered sliding member obtained by solid phase sintering or liquid phase sintering contains any element of Cu and Mn, which are elements that promote the formation of a ferrite phase (α phase) structure. In the sintering, the substrate exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, and free cementite is not precipitated in the structure.

  According to the present invention, there is provided an Fe-based sintered sliding member comprising an Fe powder, a Cu—Fe—Mn alloy powder, a Co—Mo—Cr—Si superalloy powder, and a C powder, the Cu component being 4.45 to 18.6 mass%, Mn component 0.2-1.2 mass%, Co component 3.1-9.3 mass%, Mo component 1.4-4.2 mass%, Cr component 0.4-1. 2% by mass, Si component 0.1-0.3% by mass, C component 1.0-5.0% by mass, balance Fe component, and the base structure is a pearlite structure or a structure in which pearlite and a part of ferrite coexist In addition, a C component, a Cu-Fe-Mn alloy, and a Co-Mo-Cr-Si superalloy are dispersed and contained in the structure of the base material, and the conformability is good, and the load resistance and wear resistance are improved. An Fe-based sintered sliding member with improved dynamic characteristics and a method for manufacturing the same can be provided.

Fe component 62 mass% obtained by liquid phase sintering at a temperature of 1100 ° C, Cu-Fe-Mn alloy 20 mass%, Co-Mo-Cr-Si superalloy component 15 mass%, C component 3 mass% 2 is a micrograph (magnification 400 times) of an Fe-based sintered sliding member. It is a perspective explanatory view showing a thrust test method. It is a perspective explanatory view showing a journal swing test method. It is a perspective explanatory view showing a journal rotation test method.

  Next, embodiments of the present invention will be described in detail. Note that the present invention is not limited to these examples.

  The Fe-based sintered sliding member of the present invention is an Fe-based sintered sliding member composed of Fe powder, Cu-Fe-Mn alloy powder, Co-Mo-Cr-Si superalloy powder, and C powder, Cu component 4.45 to 18.6% by mass, Mn component 0.2 to 1.2% by mass, Co component 3.1 to 9.3% by mass, Mo component 1.4 to 4.2% by mass, Cr component It consists of 0.4 to 1.2% by mass, Si component 0.1 to 0.3% by mass, C component 1.0 to 5.0% by mass, and the remaining Fe component. It is characterized by exhibiting a structure in which part ferrite coexists, and a C component, a Cu—Fe—Mn alloy, and a Co—Mo—Cr—Si superalloy dispersed in the structure of the substrate.

In the Fe-based sintered sliding member of the present invention, the Fe component as a main component is a reduction having a particle size passing through an 80 mesh sieve (177 μm or less) and an apparent density of about 2.4 to 3.0 Mg / m ^3. Fe powder and atomized Fe powder (water atomized Fe powder) are preferably used. The specific surface area by gas adsorption method (BET-ISO 9277) in these Fe powder, the atomized Fe powder 60~80m ² / kg, the reduction Fe powder is 80~100m ² / kg. Atomized Fe powder has few pores in the powder and a small specific surface area, whereas reduced Fe powder has relatively many pores and many irregularities on the surface, and has a higher specific surface area than atomized Fe powder.

The Cu component and the Mn component blended in a predetermined ratio with respect to the Fe component constituting the main component are used in the form of a Cu-Fe-Mn alloy. The Cu component and Mn component in these alloys are elements that promote the formation of a ferrite phase (α phase) structure, and suppress the reaction between the Fe component, which is the main component, and the C component described later in the sintering process. This serves to prevent the precipitation of free cementite in the structure of the sintered body. Although the effect of suppressing the reaction between the Fe component and the C component in the sintering process of the Cu component and the Mn component is not clear, the Cu component and the Mn component are the main components because these elements are pre-alloyed. It is presumed that this is because it preferentially dissolves in the Fe component formed and prevents the C component from dissolving in the Fe component as much as possible.

  The component composition of this Cu—Fe—Mn alloy component is composed of 89 to 93% by mass of Cu component, 3 to 5% by mass of Fe component, and 4 to 6% by mass of Mn component. 5 to 20% by mass with respect to Fe component constituting the component, that is, Cu component 4.45 to 18.6% by mass, Fe component 0.15 to 1.0% by mass, Mn component 0.2 to 1 with respect to Fe component .2% by mass is blended.

  The component composition of the Co—Mo—Cr—Si superalloy component blended at a predetermined ratio with respect to the Fe component and the Cu—Fe—Mn alloy component constituting the main component is as follows: Co component 62 mass%, Mo component 28 The Cu-Fe-Mn alloy component is composed of 5 to 15 mass% with respect to the Fe component and the Cu-Fe-Mn alloy component, which are the main components. Co component 3.1 to 9.3 mass%, Mo component 1.4 to 4.2 mass%, Cr component 0.4 to 1.2 mass%, Si component 0.1 to 0.3 mass% Blended.

  This Co-Mo-Cr-Si superalloy component is hard, and is blended with the Fe component and Cu-Fe-Mn alloy component which are the main components, so that the base pearlite structure or pearlite and a part of ferrite coexist. It is dispersed and contained in the structure, and is effective in improving the load resistance and wear resistance of the sintered body. The blending ratio of the Co—Mo—Cr—Si superalloy is 5 to 15% by mass. If the blending ratio is less than 5% by mass, the effect of improving the load resistance and wear resistance is not sufficiently exhibited. If the blending ratio exceeds 50%, the proportion of the hard Co—Mo—Cr—Si superalloy component dispersed increases, and on the contrary, there is a risk of damaging the counterpart material such as the shaft.

  As described above, natural graphite or artificial graphite is preferably used as component C. This C component is dispersed and contained at a ratio of 1.0 to 5.0% by mass in the base pearlite structure or the structure in which pearlite and a part of ferrite coexist, and the C component has its own solid lubricating action. It plays a role as a holding body for a lubricating oil to be described later. In particular, when the blending amount of the C component is 3% by mass or more, self-lubricating property due to the solid lubricating action is imparted.

Lubricating oil provides a liquid lubricating action to the Fe-based sintered sliding member and exhibits an action of further enhancing self-lubricating properties in combination with the solid lubricating action by the C component described above. This lubricating oil is contained in the Fe-based sintered sliding member at a rate of 10 to 15% by volume.

The manufacturing method of the Fe-based sintered sliding member having the above-described component composition is based on the Cu-Fe-Mn alloy powder consisting of Mn 4-6 mass%, Fe 3-5 mass% and the balance Cu with respect to the main component Fe powder. 5 to 20% by mass, Co-Mo-Cr-Si superalloy powder consisting of 62% by mass of Co, 28% by mass of Mo, 8% by mass of Cr, and 2% by mass of Si, and C powder 1.0 to 5.0 After mixing each mass% and mixing to form a mixed powder, the mixed powder is loaded into a mold to form a green compact of a desired shape, and the green compact is placed in a neutral or reducing atmosphere. Sintering is performed at a temperature of 1000 to 1150 ° C. for 30 to 90 minutes in an adjusted heating furnace.

The Cu—Fe—Mn alloy powder blended with the Fe powder as the main component has a liquidus point at a temperature of 1050 ° C., and sintering at a temperature of less than 1050 ° C. is solid phase sintering, Sintering at a temperature of 1050 ° C. or higher results in liquid phase sintering. In solid phase sintering at a sintering temperature of less than 1050 ° C., the Cu—Fe—Mn alloy component is dispersed and contained in the base pearlite structure or a structure in which pearlite and a part of ferrite coexist, and the sintering temperature is 1050. In the liquid phase sintering at a temperature of 0 ° C. or higher, the Cu—Fe—Mn alloy component is dispersed and contained in the form of a network at the grain boundaries of the pearlite structure of the substrate or the structure in which pearlite and part of ferrite coexist.

FIG. 1 shows an Fe component 62 mass% obtained by liquid phase sintering at a temperature of 1100 ° C., a Cu—Fe—Mn alloy 20 mass%, a Co—Mo—Cr—Si superalloy component 15 mass%, and a C component 3. It is a microscope picture (400-times multiplication factor) of the Fe-type sintered sliding member which consists of mass%.

In FIG. 1, the site indicated by the arrow a (matrix) is a structure in which pearlite and a part of ferrite of the base material coexist, and the site indicated by the arrow b (Cu liquid phase part) is dispersed and contained in the grain boundary of the structure. -Co-Mo-Cr-Si superalloy component in which the site indicated by arrow c (alloy) is dispersed and contained in the structure in the -Fe-Mn alloy component.

In the micrograph shown in FIG. 1 above, the site of the structure where the base pearlite and some ferrite coexist is 350 to 450 in micro Vickers hardness (HMV), and the site of the Cu-Fe-Mn alloy is micro The Vickers hardness indicates 100 to 120, and the Co—Mo—Cr—Si superalloy region indicates micro Vickers hardness of 540 to 770.

  In the structure in which the base pearlite and some ferrite coexist, the Cu-Fe-Mn alloy having a hardness lower than the hardness of the site of the structure and the Co-Mo-Cr having a hardness higher than the hardness of the site of the structure When the -Si superalloy is dispersed and contained, the conformability is good in sliding with the counterpart material, and the sliding characteristics such as load resistance and wear resistance are improved.

  Next, the present invention will be described with reference to each embodiment. Needless to say, the present invention is not limited to the following examples.

Atomized Fe powder with an average particle size of 70 μm (composed of 90.5% by mass of Cu component, 4.1% by mass of Fe component, and 5.4% by mass of Mn component with respect to “Atomel 300M (trade name)” manufactured by Kobe Steel) Co-- consisting of 15% by mass of Cu-Fe-Mn alloy powder (produced by Fukuda Metal Foil Powder Co., Ltd.) with an average particle size of 75 μm, 62% by mass of Co with an average particle size of 63 μm, 28% by mass of Mo, 8% by mass of Cr, and 2% by mass of Si 7% by mass of Mo—Cr—Si superalloy powder (“DAPKMC400 (trade name)” manufactured by Daido Steel Co., Ltd.) and natural graphite powder having an average particle size of 40 μm as the C component (“CB150 (trade name)” manufactured by Nippon Graphite Co., Ltd.) ) 3% by mass, mixed for 20 minutes with a V-type mixer and mixed powder (Cu component 13.58% by mass, Mn component 0.81% by mass, Co component 4.34% by mass, Mo component 1.96) Mass%, Cr composition 0.56% by mass, Si component 0.14% by mass, Fe component 75.61% by mass, and C component 3% by mass) Next, this mixed powder was loaded into a mold, and a molding pressure of 490 Mpa (5 Ton / cm ² ) to obtain a green compact.

This square green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1100 ° C. for 60 minutes, and then taken out from the heating furnace to obtain a square Fe-based sintered material. This Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having a side of 30 mm and a thickness of 5 mm. The density of this Fe-based sintered sliding member was 5.76 Mg / m ³ . The base structure of this Fe-based sintered sliding member exhibits a structure in which pearlite and a part of ferrite coexist, and there is no generation of free cementite in the structure. In this structure, a Cu-Fe-Mn alloy and Co-Mo are formed. It was confirmed that the —Cr—Si superalloy was dispersed. And the site | part of the structure | tissue in which pearlite and a part ferrite coexisted showed 400 by micro Vickers hardness, the hardness of the site | part of a Cu-Fe-Mn alloy showed 110 by micro Vickers hardness, Co-Mo- The hardness of the Cr-Si superalloy portion was 570 in terms of micro Vickers hardness. Subsequently, this Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based oil impregnated sintered sliding member having an oil content of 12% by volume.

  With respect to the atomized Fe powder having an average particle diameter of 70 μm similar to that of Example 1, 20% by mass of Cu—Fe—Mn alloy powder having an average particle diameter of 75 μm similar to that of Example 1 and an average similar to that of Example 1 15% by mass of Co-Mo-Cr-Si superalloy powder having a particle size of 63 μm and 3% by mass of natural graphite powder having an average particle size of 40 μm as in Example 1 were mixed for 20 minutes with a V-type mixer. Mixed powder (Cu component 18.1% by mass, Mn component 1.08% by mass, Co component 9.30% by mass, Mo component 4.20% by mass, Cr component 1.20% by mass, Si component 0.30% by mass) %, Fe component 62.82 mass%, C component 3 mass%). Thereafter, a green compact was obtained in the same manner as in Example 1.

This square green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1150 ° C. for 60 minutes, and then taken out of the heating furnace to obtain a square Fe-based sintered material. The Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having a side of 30 mm and a thickness of 5 mm. The density of this Fe-based sintered sliding member was 5.92 Mg / m ³ . As shown in FIGS. 1 and 2, the structure exhibits a structure in which pearlite and a part of ferrite coexist, and free cementite is not generated in the structure, and a Cu—Fe—Mn alloy is formed in a network at the grain boundary of the structure. It was confirmed that Co-Mo-Cr-Si superalloy was dispersed and contained in the structure. And the site | part of the structure | tissue in which pearlite and a part ferrite coexisted showed 400 by micro Vickers hardness, the hardness of the site | part of a Cu-Fe-Mn alloy showed 110 by micro Vickers hardness, Co-Mo- The hardness of the Cr-Si superalloy portion was 640 in terms of micro Vickers hardness. Subsequently, the Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based oil-impregnated sintered sliding member having an oil content of 10% by volume.

Mixed powder similar to Example 1 (Cu component 13.58 mass%, Mn component 0.81 mass%, Co component 4.34 mass%, Mo component 1.96 mass%, Cr component 0.56 mass%, Si component 0.14 mass%, Fe component 75.61 mass%, C component 3 mass%) were prepared. This mixed powder was loaded into a mold and molded at a molding pressure of 490 Mpa (5 tons / cm ² ) to obtain a cylindrical green compact.

This cylindrical green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1100 ° C. for 60 minutes, and then taken out from the heating furnace to obtain a cylindrical Fe-based sintered material. This Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having an inner diameter of 20 mm, an outer diameter of 28 mm, and a length of 15 mm. The density of this Fe-based sintered sliding member was 5.84 Mg / m ³ . The base structure of this Fe-based sintered sliding member exhibits a structure in which pearlite and a part of ferrite coexist, and there is no generation of free cementite in the structure. In this structure, a Cu-Fe-Mn alloy and Co-Mo are formed. It was confirmed that the —Cr—Si superalloy was dispersed. And the site | part of the structure | tissue in which pearlite and a part ferrite coexisted showed 400 by micro Vickers hardness, the hardness of the site | part of a Cu-Fe-Mn alloy showed 110 by micro Vickers hardness, Co-Mo- The hardness of the Cr-Si superalloy portion was 572 in terms of micro Vickers hardness. Subsequently, this Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based oil impregnated sintered sliding member having an oil content of 12% by volume.

  Mixed powder similar to Example 2 (Cu component 18.1% by mass, Mn component 1.08% by mass, Co component 9.30% by mass, Mo component 4.20% by mass, Cr component 1.20% by mass, Si component 0.30 mass%, Fe component 62.82 mass%, C component 3 mass%) were prepared. Thereafter, a green compact was obtained in the same manner as in Example 3.

The cylindrical green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1150 ° C. for 60 minutes, and then taken out from the heating furnace to obtain a cylindrical Fe-based sintered material. This Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having an inner diameter of 20 mm, an outer diameter of 28 mm, and a length of 15 mm. The density of this Fe-based sintered sliding member was 5.92 Mg / m ³ . The base structure of this Fe-based sintered sliding member exhibits a structure in which pearlite and a part of ferrite coexist, and there is no generation of free cementite in the structure. In this structure, a Cu-Fe-Mn alloy and Co-Mo are formed. It was confirmed that the —Cr—Si superalloy was dispersed. And the site | part of the structure | tissue in which pearlite and a part ferrite coexisted showed 400 by micro Vickers hardness, the hardness of the site | part of a Cu-Fe-Mn alloy showed 110 by micro Vickers hardness, Co-Mo- The hardness of the Cr-Si superalloy portion was 642 in terms of micro Vickers hardness. Subsequently, the Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based oil-impregnated sintered sliding member having an oil content of 10% by volume.

Comparative Example 1

For the atomized Fe powder having the average particle size of 70 μm as in Example 1, it is composed of 90.5% by mass of Cu component, 4.1% by mass of Fe component, and 5.4% by mass of Mn component as in Example 1. 12% by mass of Cu—Fe—Mn alloy powder having an average particle size of 75 μm and 3% by mass of natural graphite having an average particle size of 40 μm as in Example 1 as a C component were mixed for 20 minutes using a V-type mixer. To obtain a mixed powder (Cu component 10.86% by mass, Mn component 0.65% by mass, Fe component 85.49% by mass, C component 3% by mass). Next, this mixed powder was loaded into a mold and molded at a molding pressure of 490 Mpa (5 tons / cm ² ) to obtain a green compact.

This square green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1100 ° C. for 60 minutes, and then taken out from the heating furnace to obtain a square Fe-based sintered material. The Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having a side of 30 mm and a thickness of 5 mm. The density of this Fe-based sintered sliding member was 6.7 Mg / m ³ . The structure exhibited a structure in which pearlite and a part of ferrite coexisted, and no free cementite was produced in the structure, and it was confirmed that a Cu—Fe—Mn alloy was dispersedly contained in the structure. And the part of the structure where pearlite and ferrite partially coexist is 400 in terms of micro Vickers hardness, and the part of the Cu-Fe-Mn alloy dispersed and contained in the structure is 110 in terms of micro Vickers hardness. It was. Subsequently, the Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based sintered sliding member having an oil content of 10% by volume.

Comparative Example 2

For an atomized Fe powder having an average particle size of 70 μm as in Example 1, Cu— with an average particle size of 75 μm comprising 90.5% by mass of Cu component, 4.1% by mass of Fe component and 5.4% by mass of Mn component. 10% by mass of Fe—Mn alloy powder and 3% by mass of natural graphite having an average particle size of 40 μm as in Example 1 are mixed as the C component, mixed for 20 minutes with a V-type mixer, and mixed powder (Cu component 9 0.05% by mass, 0.54% by mass of Mn component, 87.41% by mass of Fe component, and 3% by mass of C component). Next, this mixed powder was loaded into a mold and molded at a molding pressure of 490 Mpa (5 tons / cm ² ) to obtain a cylindrical green compact.

This cylindrical green compact was placed in a heating furnace adjusted to a hydrogen gas atmosphere, liquid phase sintered at a temperature of 1100 ° C. for 60 minutes, and then taken out from the heating furnace to obtain a cylindrical Fe-based sintered material. This Fe-based sintered material was machined to obtain an Fe-based sintered sliding member having an inner diameter of 20 mm, an outer diameter of 28 mm, and a length of 15 mm. The density of this Fe-based sintered sliding member is 6.6 Mg / m ³ , and the structure exhibits a structure in which pearlite and a part of ferrite coexist, and free cementite is not generated in the structure. It was confirmed that the Cu—Fe—Mn alloy was dispersed and contained in a network. The site | part of the structure | tissue in which a pearlite and a part ferrite coexist was 400 in micro Vickers hardness, and the site | part of the Cu-Fe-Mn alloy dispersedly contained in this structure | tissue was 110 in micro Vickers hardness. Subsequently, the Fe-based sintered sliding member was subjected to oil impregnation treatment to obtain an Fe-based oil-impregnated sintered sliding member having an oil content of 10% by volume.

  Next, the results of evaluating the sliding characteristics of the Fe-based oil-impregnated sintered sliding members obtained in the above-described Examples and Comparative Examples will be described. For the Fe-based oil-impregnated sintered sliding member obtained in Example 1, Example 2 and Comparative Example 1, the thrust sliding characteristics were evaluated according to the thrust test conditions shown below, and Example 3, Example 4 and Comparative Example For the Fe-based oil-impregnated sintered sliding member obtained in Example 2, journal swing sliding characteristics and journal rotation sliding characteristics were evaluated according to the journal swing test conditions and journal rotation test conditions shown below.

<Thrust test conditions>
Speed 1.3m / min
Load (surface ^{pressure) 78.4Mpa (800kgf / cm 2)} , 88.24Mpa (900k gf / cm 2), 98Mpa (1000kgf / cm 2)
Test time 20 hours Counterpart material Carbon steel for machine structure (S45C) quenching material Lubrication conditions Lithium grease is applied to the sliding surface at the start of the test

<Test method>
As shown in FIG. 2, a plate-shaped bearing test piece (Fe-based oil-impregnated sintered sliding member) 1 is fixed, and a cylindrical body 2 serving as a mating member is placed from above the plate-shaped bearing test piece 1 (in the direction of arrow A) The cylindrical body 2 is rotated in the direction of arrow B while a predetermined load is applied to the surface 3, and the coefficient of friction between the plate-shaped bearing test piece 1 and the counterpart material 2 and the plate-shaped bearing after a predetermined test time has elapsed. The amount of wear of the test piece 1 was measured.

<Journal rocking test conditions>
Speed 3m / min
Load (surface ^{pressure) 24.5Mpa (250kgf / cm 2)} , 34.3Mpa (350kgf / cm 2), 44.1Mpa (450kgf / cm 2)
Swing angle ± 45 °
Test time 100 hours Mating material Bearing steel (SUJ2 hardened material)
Lubrication conditions Apply lithium grease to the sliding surface at the start of the test

<Test method>
As shown in FIG. 3, a cylindrical bearing test piece (Fe-based oil-impregnated sintered sliding member) 10 is loaded and fixed, and the rotating shaft 20 as a counterpart material is oscillated and rotated at a constant sliding speed. The friction coefficient between the cylindrical bearing test piece 10 and the rotating shaft 20 and the wear amount of the cylindrical bearing test piece 10 after a predetermined test time were measured.

<Journal rotation test conditions>
Speed 10m / min
Load (surface pressure) 29.4 Mpa (300 kgf / cm ² ), 39.2 Mpa (400 kgf / cm ² )
Test time 100 hours Mating material Bearing steel (SUJ2 hardened material)
Lubrication conditions Apply lithium grease to the sliding surface at the start of the test

  As shown in FIG. 4, a cylindrical bearing test piece (Fe-based oil-impregnated sintered sliding member) 10 is loaded and fixed, and the rotating shaft 20 as a counterpart material is rotated at a constant sliding speed to form a cylindrical shape. The friction coefficient between the bearing test piece 10 and the rotating shaft 20 and the wear amount of the cylindrical bearing test piece 10 after a predetermined test time were measured.

  The evaluation results of the sliding characteristics performed under the above test conditions are as shown in Tables 1 to 3.

In the above table, the friction coefficient * of the thrust load of Comparative Example 1 at 88.24 Mpa suddenly increased at 4 hours from the start of the test, so the test was stopped at that time.

In the above table, the friction coefficient ** at the swing load of 34.3 Mpa of Comparative Example 2 suddenly increased the friction coefficient 6 hours after the start of the test, so the test was stopped at that time.

In the above table, the friction coefficient *** at a rotational load of 29.434.3 Mpa of Comparative Example 2 suddenly increased the friction coefficient 8 hours after the start of the test, so the test was stopped at that time.

From the test results shown in Table 1, the Fe-based sintered sliding members of Example 1 and Example 2 are stable throughout the test time even under high load conditions exceeding a load (surface pressure) of 78.4 Mpa (800 kgf / cm ² ). The amount of wear after the test was extremely small. Furthermore, from the test results shown in Table 2 and Table 3, Fe-based sintered sliding member of Example 3 and Example 4, the load 34.3Mpa (350kgf / cm ²⁾ or Load 29.4 MPa (300 kgf / cm ² The friction coefficient remained stable throughout the test time even under high load conditions exceeding), and the amount of wear after the test was extremely small.

Industrial application fields

  As described above, the present invention is an Fe-based sintered sliding member comprising an Fe powder, a Cu—Fe—Mn alloy powder, a Co—Mo—Cr—Si superalloy powder, and a C powder, and includes a Cu component. 4.45 to 18.6% by mass, Mn component 0.2 to 1.2% by mass, Co component 3.1 to 9.3% by mass, Mo component 1.4 to 4.2% by mass, Cr component 0. 4 to 1.2% by mass, Si component 0.1 to 0.3% by mass, C component 1.0 to 5.0% by mass, and the balance Fe component. In addition, a C component, a Cu-Fe-Mn alloy, and a Co-Mo-Cr-Si superalloy are dispersed in the structure of the base material. It exhibits good sliding properties with excellent load resistance and wear resistance. Therefore, the Fe sintered sliding member of the present invention can be applied to sliding applications such as bearings, sliding plates, and washers.

1 Plate bearing test piece (Fe-based sintered sliding member)
2 Cylindrical body (partner material)
10 Cylindrical bearing test piece (Fe-based sintered sliding member)
20 Rotating shaft (partner material)

The component composition of the Co—Mo—Cr—Si superalloy component blended at a predetermined ratio with respect to the Fe component and the Cu—Fe—Mn alloy component constituting the main component is as follows: Co component 62 mass%, Mo component 28 The Co-Mo-Cr-Si superalloy component is composed of 5 to 15% by mass with respect to the Fe component and Cu-Fe-Mn alloy component as main components. %, That is, Co component 3.1 to 9.3 mass%, Mo component 1.4 to 4.2 mass%, Cr component 0.4 to 1.2 mass%, Si component 0.1 to 0.3 mass% It is blended at a ratio of

Claims (7)

  A Fe-based sintered sliding member composed of Fe powder, Cu-Fe-Mn alloy powder, Co-Mo-Cr-Si superalloy powder, and C powder, and having a Cu component of 4.45 to 18.6% by mass, Mn component 0.2-1.2% by mass, Co component 3.1-9.3% by mass, Mo component 1.4-4.2% by mass, Cr component 0.4-1.2% by mass, Si component 0.1 to 0.3% by mass, C component 1.0 to 5.0% by mass, and the balance Fe component, and the substrate structure exhibits a pearlite structure or a structure in which pearlite and a part of ferrite coexist, A Fe-based sintered sliding member in which a C component, a Cu—Fe—Mn alloy, and a Co—Mo—Cr—Si superalloy are dispersed in the structure of   The Cu-Fe-Mn alloy is dispersed and precipitated in a network form at grain boundaries of the pearlite structure of the substrate or the structure in which pearlite and a part of ferrite coexist. Fe-based sintered sliding member.   The Fe-based sintered sliding member according to claim 1 or 2, wherein the C component is made of natural graphite or artificial graphite.   The Fe-based sintered sliding member according to any one of claims 1 to 3, wherein the lubricating oil is contained at a ratio of 10 to 15% by volume.   With respect to Fe powder as a main component, Cu—Fe—Mn alloy powder consisting of 4 to 6 mass% of Mn, 3 to 5 mass% of Fe and the balance Cu, 62 mass% of Co, 28 mass% of Mo, 8 mass% of Cr After blending 5-15% by mass of Co-Mo-Cr-Si superalloy powder consisting of 2% by mass of Si and 1.0-5.0% by mass of C powder, and mixing them to form a mixed powder, The mixed powder is loaded into a mold to form a green compact of a desired shape, and the green compact is baked at a temperature of 1000 to 1150 ° C. for 30 to 90 minutes in a heating furnace adjusted to a neutral or reducing atmosphere. A method for producing an Fe-based sintered sliding member, characterized by comprising:   The method for producing an Fe-based sintered sliding member according to claim 5, wherein the C powder is made of natural graphite or artificial graphite.   7. After the green compact is sintered to obtain an Fe-based sintered sliding member, this is subjected to an oil impregnation treatment and contains lubricating oil at a ratio of 10 to 15% by volume. The manufacturing method of the Fe-type sintered sliding member as described in 2.