JP2010031373A - Multi-layered sintered slide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-layered sintered slide member excellent in fatigue durability, load withstanding characteristics, and frictional wear characteristics even in applications where a high facial pressure over the allowable facial pressure is applied. <P>SOLUTION: The multi-layered sintered slide member is composed of a backing metal and a porous sintered layer integrally diffusion-bonded to the backing metal and including 3-10 wt.% Sn, 10-30 wt.% Ni, 0.5-4 wt.% P, 30-50 wt.% Fe, 1-10 wt.% of high-speed tool steel component, 1-5 wt.% of graphite, and 20-55 wt.% copper. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer sintered sliding member that is particularly suitable for use under high load and low speed conditions. More specifically, the present invention relates to a multilayer sintered alloy layer integrally joined to a back metal and the back metal. The present invention relates to a layer sintered sliding member.

  Conventionally, as a sintered sliding member composed of multiple layers, a so-called wound bush is obtained by integrally bonding a porous sintered alloy layer to the surface of a thin steel plate and winding the sintered alloy layer inside in a cylindrical shape. There is a cylindrical sliding member in which a porous sintered alloy layer is integrally joined to an inner surface of a bearing or a steel pipe via an adhesive. However, in the former wound bush bearing, when the cylindrical alloy is bent, a large compressive stress is applied to the sintered alloy layer, which may cause a decrease in bonding strength between the thin steel plate and the sintered alloy layer or unevenness. In addition, the bending method cannot increase the thickness of the sintered alloy layer, which naturally involves a problem that the range of use as a sliding member is limited. Further, the latter cylindrical sliding member has a problem that it is difficult to obtain a strong bonding strength between the inner surface of the steel pipe and the porous sintered alloy layer.

  In view of the above circumstances, the present applicant has copper (Cu) as a main component on the inner surface of a back metal made of steel pipe, and a certain amount of tin (Sn), nickel (Ni), phosphorus (P) and graphite ( C) a multilayer sintered sliding member integrally joined with a porous sintered alloy layer, and a porous sintered alloy layer further joined with a certain amount of iron (Fe). A multilayer sintered sliding member (Patent Document 1) and a multilayer sintered sliding member (Patent Document 2) in which a porous sintered alloy layer similar to the above is integrally bonded to the surface of a back plate made of a steel plate. Proposed).

Japanese Patent Publication No.59-39481 Japanese Patent Publication No. 7-91569

  In the multilayer sintered sliding member described in Patent Document 1 and Patent Document 2 above, Ni component in the component diffuses to the surface of the steel back metal during sintering, and the interface is alloyed, so The bonding strength of the gold layer with the steel back metal is increased, and a Ni-P alloy is formed by partially alloying with P in the component, and the copper alloy and the Ni-P alloy having good wettability are combined with the sintered alloy layer and the steel. The sintered alloy layer is firmly bonded to the steel back metal in combination with the alloying by diffusion of Ni at the interface with the back metal. And since the porous sintered alloy layer and the steel back metal are firmly joined, the load characteristics are greatly improved, and in combination with the frictional wear characteristics of the sintered alloy layer, the sintered sliding member can be applied. This expands the range and enables application to high loads (high surface pressure) that could not be achieved with conventional sintered sliding members.

However, the permissible surface pressure of the multilayer sintered sliding member is about 49 MPa (500 kgf / cm ² ), and applications where a higher surface pressure is applied, such as a toggle bush of an injection molding machine or a hydraulic excavator. For joint bearings in construction machines, further improvements are required from the viewpoint of fatigue resistance and wear resistance of the porous sintered alloy layer.

  As a result of intensive studies to further improve the load bearing characteristics and frictional wear characteristics of the multilayer sintered sliding member, the present inventors have further added a predetermined amount of high speed to the porous sintered alloy layer. By containing the tool steel component, the fatigue durability of the porous sintered alloy layer can be improved, the load bearing characteristics and the friction and wear characteristics can be improved, and it can be applied to the high load (high surface pressure) applications. The knowledge that there is.

  The present invention has been completed on the basis of the above knowledge, and the purpose thereof is excellent in fatigue durability, load bearing characteristics and friction and wear characteristics even in applications where high surface pressure exceeding the allowable surface pressure acts. Another object of the present invention is to provide a multilayer sintered sliding member.

  The multilayer sintered sliding member of the present invention has a tin component of 3 to 10% by weight, a nickel component of 10 to 30% by weight, a phosphorus component of 0.5 to 4% by weight, an iron component of 30 to 50% by weight, A porous sintered alloy layer containing 1 to 10% by weight of a high-speed tool steel component, 1 to 5% by weight of a graphite component, and 20 to 55% by weight of a copper component is integrally diffusion bonded to the back metal. And

According to the multilayer sintered sliding member of the present invention, the Ni component diffuses to the surface of the back metal during sintering to alloy its interface, and further forms a partial liquid phase with the P component in the component to form Cu- generates a Ni-Sn alloy and wettability good Ni-P alloy _(Ni 3 P), the Ni ₃ P is interposed at the interface between the backing plate and the porous sintered alloy layer, by diffusion of the Ni component at the interface Combined with alloying, the porous sintered alloy layer is firmly joined and integrated with the back metal. In addition, Ni ₃ P, which is a hard intermetallic compound produced during sintering, intervenes in the grain boundary of the Cu—Ni—Sn alloy phase, and is itself a fine high intermetallic compound, mainly composed of carbide. Since the speed tool steel component is dispersed and contained in the grain boundaries of the Cu—Ni—Sn alloy phase and the αFe phase, the fatigue durability, load resistance and frictional wear characteristics of the porous sintered alloy layer are greatly improved.

  In the multilayer sintered sliding member of the present invention, the porous sintered alloy layer integrally diffusion bonded to the back metal preferably contains 5 to 20% by volume of lubricating oil. As the lubricating oil, mineral oil such as engine oil and gear oil, and synthetic oil such as ester oil are appropriately selected according to the use.

  This lubricating oil can improve the friction and wear characteristics in combination with the lubricity of the graphite component itself dispersedly contained in the porous sintered alloy layer.

  In the multilayer sintered sliding member of the present invention, the high-speed tool steel component is preferably tungsten (W) -based high-speed tool steel or molybdenum (Mo) -based high-speed tool steel. Steel is preferably used.

  In the multilayer sintered sliding member of the present invention, the backing metal is preferably made of a steel pipe or a flat steel plate, and the porous sintered alloy layer is a cylindrical inner surface or plate of the steel pipe, block It is good that it is diffusion-bonded integrally to the flat surface of a flat plate-like steel plate.

  Multi-layer sintered sliding members with a porous sintered alloy layer integrally diffusion-bonded on a cylindrical inner surface are cylindrical bearings, and multi-layer sintered with a porous sintered alloy layer integrally diffusion-bonded on a flat surface The sliding member can be used as it is, in the form of a sliding plate, a sliding plate or a cylindrical wound with a porous sintered alloy layer inside, as a so-called wound bush, or even on the flat surface of the block. A multilayer sintered sliding member in which a porous sintered alloy layer is integrally diffusion-bonded is applied as a component constituting a jig.

According to the present invention, Sn component 3 to 10% by weight, Ni component 10 to 30% by weight, P component 0.5 to 4% by weight, Fe component 30 to 50% by weight, high speed tool steel component 1 A multilayer sintered sliding member in which a porous copper-based sintered body containing 10 to 10% by weight, graphite component 1 to 5% by weight and Cu component 20 to 55% by weight is integrally diffusion bonded to a back metal. Ni ₃ P, which is a hard intermetallic compound produced during sintering, intervenes in the grain boundary of the Cu—Ni—Sn alloy phase, and is itself a fine high intermetallic compound, mainly composed of carbide. Since the tool steel component is dispersed and contained in the grain boundaries of the Cu-Ni-Sn alloy phase and the αFe phase, the fatigue durability, load resistance and frictional wear characteristics of the porous sintered alloy layer are greatly improved. It is possible to provide a multilayer sintered sliding member that can be applied to applications where high surface pressure acts. The

  Hereinafter, the multilayer sintered sliding member of the present invention will be described in detail.

  In the multilayer sintered sliding member of a preferred example of the present invention, the Sn component is 3 to 10 wt%, the Ni component is 10 to 30 wt%, the P component is 0.5 to 4 wt%, and the Fe component is 30 to 50 wt%. %, A high-speed tool steel component 1 to 10% by weight, a graphite component 1 to 5% by weight, and a Cu component 20 to 55% by weight are integrally diffusion bonded to the back metal. .

  In such a multilayer sintered sliding member, the Cu component forming the porous sintered alloy layer contributes to the improvement of the strength, toughness, mechanical strength and wear resistance of the porous sintered alloy layer. The Sn component generates a liquid phase from a temperature of 232 ° C. in the sintering process, and is alloyed with the Cu component and the Ni component described later to form a Cu—Ni—Sn alloy, and the strength of the porous sintered alloy layer is reduced. Contributes to improved toughness, mechanical strength and wear resistance. If the amount of Sn component is less than 3% by weight, the above-described effects are not sufficiently exhibited, and if it exceeds 10% by weight, the sinterability is adversely affected. Therefore, the blending amount of the Sn component is 3 to 10% by weight, especially 5 to 8% by weight.

The Ni component forms part of a liquid phase with the P component described later during sintering, and forms a Ni-P alloy (Ni ₃ P) with good wettability with the Cu-Ni-Sn alloy. Intervening at the interface between the porous sintered alloy layer of Sn alloy phase and the back metal, and combining the alloy by diffusion of Ni component at the interface to firmly bond and integrate the porous sintered alloy layer to the back metal Make. In addition, the Ni ₃ P intermetallic compound produced during sintering is hard, and this intervenes at the grain boundary of the Cu—Ni—Sn alloy phase, thereby improving the wear resistance of the porous sintered alloy layer. . If the blending amount of the Ni component is less than 10% by weight, the above-mentioned effect cannot be obtained, and even if blending exceeding 30% by weight, a remarkable difference does not appear in the above-mentioned effect, so the upper limit of the blending amount is 30% by weight. %. Therefore, the blending amount of the Ni component is suitably 10 to 30% by weight, especially 10 to 20% by weight.

  The P component is partly alloyed with the Cu component and the Ni component in the component to increase the strength of the ground of the porous sintered alloy layer and contribute to the improvement of wear resistance. Since the P component has a strong reducing power, it has the effect of cleaning the surface of the back metal by its reducing action and promoting the alloying by the diffusion of the Ni component to the back metal surface. The effects of the Ni-P alloy are as described above. If the blending amount of the P component is less than 0.5% by weight, the above-described effect is not sufficiently exhibited, and the amount of Ni-P alloy blended by exceeding 4% by weight is increased, which may reduce the wear resistance. There is. Therefore, the P component is suitably 0.5 to 4% by weight, especially 0.5 to 2% by weight. As a P component, it is good to mix | blend with the form of a P-Cu alloy, for example, Cu-15% P alloy.

  Although the Fe component does not dissolve in the Cu component, it is dispersed in the alloy structure. In particular, the Fe component exhibits the effect of increasing the strength of the ground, and when a part of the Cu component diffuses into the Fe component during sintering, Demonstrates the effect of increasing porosity. In general, the Fe component tends to be alloyed with the P component to precipitate a hard Fe-P alloy in the presence of the P component. In the present invention, the Ni-P is used at a temperature lower than the alloying temperature of Fe-P. Is alloyed, so that the effect of suppressing the alloying of Fe—P by the Ni—P alloying is exhibited, so that a relatively large amount of Fe component up to 50% by weight can be contained. If the blending amount of the Fe component is less than 30% by weight, the above-described effects are not sufficiently exhibited. If the blending amount exceeds 50% by weight, the Fe—P alloy may be precipitated. Therefore, the Fe component is suitably 30 to 50% by weight, especially 35 to 45% by weight.

  The high-speed tool steel (SKH) component itself contains fine intermetallic compounds and carbides, which are dispersed in the sintered structure and play a role as a hard phase. The alloying element from the steel diffuses to strengthen the ground (so-called dispersion strengthening) and improve the wear resistance of the copper-based sintered body. If the blending amount of the high-speed tool steel component is less than 1% by weight, the above effect is not exhibited. If the blending amount exceeds 10% by weight, the amount of the hard phase dispersed increases, and the wear resistance decreases. . Accordingly, the blending amount of the high-speed tool steel is suitably 1 to 10% by weight, especially 2 to 3% by weight. The high-speed tool steel component is a powder of a high-speed tool steel material specified in Japanese Industrial Standard (JIS) G4403. .23 to 1.33%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50% , Mo: 4.70-5.30%, W: 5.70-6.70%, V: 2.70-3.20%, Co: 8.00-8.88% and Fe: balance, SKH50 -C: 0.77 to 0.87%, Si: 0.70% or less, Mn: 0.45% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.50 4.50%, Mo: 8.00 to 9.00%, W: 1.40 to 2.00%, V: 1 00 to 1.40% and Fe: balance, SKH51-C: 0.80 to 0.88%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50%, Mo: 4.70 to 5.20%, W: 5.90 to 6.70%, V: 1.70 to 2.10% and Fe: remainder, SKH52-C: 1.00-1.10%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr : 3.80 to 4.50%, Mo: 5.50 to 6.50%, W: 5.90 to 6.70%, V: 2.30 to 2.60% and Fe: remainder, SKH53-C : 1.15 to 1.25%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3. 0 to 4.50%, Mo: 4.70 to 5.20%, W: 5.90 to 6.70%, V: 2.70 to 3.20% and Fe: remainder, SKH54-C: 1. 25 to 1.40%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50%, Mo: 4.20-5.00%, W: 5.20-6.00%, V: 3.70-4.20% and Fe: balance, SKH55-C: 0.87-0.95%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50%, Mo: 4.70 to 5 20%, W: 5.90-6.70%, V: 1.70-2.10%, Co: 4.50-5.00% and Fe: balance, SKH56-C: 0.85-0 .9 5%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50%, Mo: 4. 70-5.20%, W: 5.90-6.70%, V: 1.70-2.10%, Co: 7.00-9.00% and Fe: balance, SKH57-C: 1. 20 to 1.35%, Si: 0.45% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.80 to 4.50%, Mo: 3.20 to 3.90%, W: 9.00 to 10.00%, V: 3.00 to 3.50%, Co: 9.50 to 10.50%, Fe: remainder, SKH58- C: 0.95 to 1.05%, Si: 0.70% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.50-4 .50%, Mo: 8.20-9.20%, W: 1.50-2.10%, V: 1.70-2.20% and Fe: balance, SKH59-C: 1.05-1 .15%, Si: 0.70% or less, Mn: 0.40% or less, P: 0.030% or less, S: 0.030% or less, Cr: 3.50 to 4.50%, Mo: 9 0.01 to 10.00%, W: 1.20 to 1.90%, V: 0.90 to 1.30%, Co: 7.50 to 8.50% and Fe: balance powder is recommended. .

  The graphite component is dispersed and contained in the sintered alloy structure to form a solid lubricating action. If the blending amount is less than 1% by weight, a solid lubricating action cannot be expected, and if it exceeds 5% by weight, the strength of the sintered alloy layer is lowered. Therefore, the blending amount of the graphite component is suitably 1 to 5% by weight, especially 2 to 3% by weight.

  Next, a method for producing a multilayer sintered sliding member in which a sintered alloy layer having the above composition is integrally joined to a back metal to form a multilayer will be described.

  As a back metal forming this multilayer sintered sliding member, a steel pipe made of carbon steel pipe for general structure (JIS-G-3444) or carbon steel pipe for mechanical structure (JIS-G-3445), or general A steel plate made of structural rolled steel (JISG3101) or carbon steel for mechanical structure (JIS-G-4051) is used.

  Hereinafter, the manufacturing method of the multilayer sintered sliding member which uses each back metal is demonstrated.

<Manufacturing method of multilayer sintered sliding member using steel pipe for backing metal>
Sn powder 3 to 10% by weight, Ni powder 10 to 30% by weight, P component of P-Cu alloy (Cu-15% P) powder 0.5 to 4% by weight with respect to Cu powder 20 to 55% by weight Then, 30-50% by weight of Fe powder, 1-10% by weight of high-speed tool steel powder, and 1-5% by weight of graphite powder are mixed with a V-type mixer to produce a mixed powder.

This mixed powder is pressed under a pressure in the range of ² to 7 ton / cm ² (196 to 686 MPa) in a required mold to produce a cylindrical molded green compact made of the mixed powder. After this molded green compact is press-fitted onto the inner surface of a steel pipe, it is placed in a heating furnace adjusted to a neutral or reducing atmosphere and sintered at a temperature of 900 to 1000 ° C. for 60 to 90 minutes. Simultaneously with the sintering of the green compact, the molded green compact is diffusion bonded to the inner surface of the steel pipe, and the sintered alloy layer is integrally diffusion bonded to the inner surface of the steel pipe. Is made.

  In this manufacturing method, when 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 green compact is filled with ceramic powder to form the green compact. The amount of expansion to the inner diameter side of the molded body is constrained and directed toward the outer diameter side, and further, the amount of shrinkage of the green compact on the inner diameter side during cooling after sintering is constrained, and this is directed toward the outer diameter side. By doing so, it is possible to obtain a strong joint between the steel pipe and the green compact.

  The multilayer sintered sliding member thus produced is machined to produce a desired cylindrical bearing and then subjected to an oil impregnation treatment, whereby lubricating oil is added to the porous sintered alloy layer in an amount of 5 to 20. It is contained at a rate of volume%.

<Manufacturing method of multilayer sintered sliding member using steel plate for backing metal>
When using a steel plate for the back metal, it is preferable to use a powder rolling method as a manufacturing method thereof, and a manufacturing method using this powder rolling method will be described. A mixed powder similar to the mixed powder in the manufacturing method of the multilayer sintered sliding member described above is prepared, and a powder binder is added to the mixed powder and mixed uniformly to prepare a raw material powder having wettability. . As the powder binder, hydroxypropylcellulose (HPC) is preferably used.

  The raw material powder is supplied to a horizontal rolling roll having twin rolls, and a rolled sheet made of a green compact is produced.

After the rolled sheet is superposed on the backing metal, the rolled sheet is placed in a sintering furnace adjusted to a neutral or reducing atmosphere at a temperature of 900 to 1000 ° C. and 0.1 to 5.0 kgf / cm ² (0 .0.0 to 0.49 MPa) for 60 to 90 minutes, and simultaneously sintering the rolled sheet, diffusion bonding of the sintered alloy layer to the back metal is performed, and the sintered alloy layer and the back metal are diffused. A multilayer sintered sliding member integrated by bonding is produced.

  The multilayer sintered sliding member thus produced is machined to produce a desired sliding plate or sliding plate, and then subjected to oil impregnation, whereby the porous sintered alloy layer is lubricated with lubricating oil. Is contained in a proportion of 5 to 20% by volume.

In the manufacturing method described above, a liquid phase of the Sn component in the component is generated at a temperature of 232 ° C. in the sintering process, and a liquid phase mainly composed of Ni—P alloy (Ni ₃ P) is generated from a temperature near 875 ° C. This is so-called liquid phase sintering in which the sintering proceeds. Hard Ni ₃ P intervenes in the grain boundary of the Cu—Ni—Sn alloy of the porous sintered alloy layer of the multilayer sintered sliding member produced by these production methods, and is itself a fine intermetallic compound And hard carbide high-speed tool steel components are dispersed and contained in the grain boundaries of the Cu-Ni-Sn alloy phase and the αFe phase, so the fatigue durability, load bearing characteristics and frictional wear of the porous sintered alloy layer The characteristics are greatly improved, and as a result, it can be applied to applications where high surface pressure acts.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example at all unless the summary is exceeded.

  Examples 1 to 5 and Comparative Examples 1 and 2 are examples in which the multilayer sintered sliding member is applied to a cylindrical sliding member (cylindrical bearing).

Examples 1-5
A steel pipe made of a general structural carbon steel pipe (STK400) having an inner diameter of 33.6 mm, an outer diameter of 45 mm, and a length of 20 mm was prepared.

  5% by weight of atomized Sn powder passing through a 250 mesh screen, 15% by weight of reduced Ni powder passing through a 250 mesh screen, and 7% of ground P-Cu alloy (P15%) powder passing through a 120 mesh screen %, Reduced Fe powder 30-45% by weight passing through a 240 mesh sieve, water atomized high speed tool steel powder 2-3% by weight passing through a 200 mesh sieve, passing through a 48 mesh sieve and 250 mesh 2 wt% of natural graphite powder that does not pass through the sieve and electrolytic Cu powder that passes through the sieve having the remaining 150 mesh are put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder (Sn: 5 wt%, Ni: 15 wt%, P: 1.05 wt%, Fe: 30-45 wt%, high speed tool steel: 2-3 wt%, natural graphite: 2 wt%, Cu: balance).

The mixed powder is loaded into a hollow part of a mold having a cylindrical hollow part, molded at a molding pressure of 5 ton / cm ² (490 MPa), and has an inner diameter of 27.4 mm, an outer diameter of 33.6 mm, and a length of 20 mm. Thus, a cylindrical green compact having a density of 6.6 to 6.8 g / cm ³ was produced.

After pressing the green compact into the inner surface of the steel pipe from the axial direction, ceramic powder (a mixture of Al ₂ O ₃ : 83 wt% and SiO ₂ : 17 wt% is formed on the inner surface of the green compact. In a sintering furnace adjusted to an ammonia decomposition gas atmosphere, sintering is performed at a temperature of 960 ° C. for 85 minutes, and simultaneously with the sintering of the green compact, diffusion bonding with the inner surface of the steel pipe is performed. The sintered alloy body and the steel pipe were joined and integrated.

Next, this was machined to obtain a multilayer sintered sliding member having an inner diameter of 30 mm, an outer diameter of 45 mm, and a length of 20 mm. The density of the porous sintered alloy layer of this multilayer sintered sliding member was 6.8 to 7.0 g / cm ³ . When this multilayered sintered sliding member was subjected to oil impregnation treatment, the oil content in the porous sintered alloy layer was 13 to 15% by volume.

Comparative Example 1
A steel pipe made of a general structural carbon steel pipe having an inner diameter of 33.6 mm, an outer diameter of 45 mm, and a length of 20 mm, similar to that in the above example, was prepared.

  8% by weight of atomized Sn powder passing through a 250 mesh screen, 28% by weight of reduced Ni powder passing through a 250 mesh screen, and 7% of ground P-Cu alloy (P15%) powder passing through a 120 mesh screen %, 5% by weight of natural graphite powder passing through a 150 mesh sieve and electrolytic Cu powder passing through a 150 mesh sieve in a V-type mixer, and mixed for 30 minutes to obtain a mixed powder ( Sn: 8% by weight, Ni: 28% by weight, P: 1.05% by weight, natural graphite: 5% by weight, Cu: balance).

The mixed powder is loaded into a hollow part of a mold having a cylindrical hollow part, molded at a molding pressure of 5 ton / cm ² (490 MPa), and has an inner diameter of 27.4 mm, an outer diameter of 33.6 mm, and a length of 20 mm. A cylindrical green compact having a density of 5.8 g / cm ³ was produced.

  After the green compact has been press-fitted into the inner surface of the steel pipe from the axial direction, the inner surface of the green compact is filled with ceramic powder (same as in the example) and adjusted to an ammonia decomposition gas atmosphere. In the sintering furnace, sintering was performed at a temperature of 960 ° C. for 60 minutes, and simultaneously with the sintering of the green compact, diffusion bonding with the inner surface of the steel pipe was performed, and the sintered alloy body and the steel pipe were Bonded and integrated.

Next, this was machined to obtain a multilayer sintered sliding member having an inner diameter of 30 mm, an outer diameter of 45 mm, and a length of 20 mm. The density of the porous sintered alloy layer of this multilayer sintered sliding member was 6.0 g / cm ³ . When this multilayered sintered sliding member was subjected to oil impregnation treatment, the oil content in the porous sintered alloy layer was 15% by volume.

Comparative Example 2
A steel pipe made of a general structural carbon steel pipe having an inner diameter of 33.6 mm, an outer diameter of 45 mm, and a length of 20 mm was prepared.

  8% by weight of atomized Sn powder passing through a 250 mesh screen, 28% by weight of reduced Ni powder passing through a 150 mesh screen, and 7% of ground P-Cu alloy (P15%) powder passing through a 120 mesh screen %, 5% by weight of natural graphite powder passing through a 150 mesh sieve and electrolytic Cu powder passing through a 150 mesh sieve in a V-type mixer, and mixed for 10 minutes to obtain a mixed powder ( Sn: 8% by weight, Ni: 28% by weight, P: 1.05% by weight, natural graphite: 5% by weight, Cu: balance).

  40% by weight of reduced Fe powder passing through a 100 mesh sieve was mixed with 60% by weight of the mixed powder, and mixed for 10 minutes with a V-type mixer to obtain a mixed powder (Sn: 4.8% by weight, Ni : 16.8% by weight, P: 0.63% by weight, Fe: 40% by weight, natural graphite: 3% by weight, Cu: balance).

The mixed powder is loaded into a hollow part of a mold having a cylindrical hollow part, molded at a molding pressure of 5 ton / cm ² (490 MPa), and has an inner diameter of 27.4 mm, an outer diameter of 33.6 mm, and a length of 20 mm. Thus, a cylindrical green compact having a density of 6.0 g / cm ³ was produced.

Thereafter, a multilayer sintered sliding member having an inner diameter of 30 mm, an outer diameter of 45 mm, and a length of 20 mm was obtained in the same manner as in Comparative Example 1. The density of the porous sintered alloy layer of this multilayer sintered sliding member was 6.4 g / cm ³ . When this multilayered sintered sliding member was subjected to oil impregnation treatment, the oil content in the porous sintered alloy layer was 14% by volume.

  Next, with respect to the multilayer sintered sliding members obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the friction and wear characteristics were tested under the test conditions shown in Table 1, and the fatigue durability was tested under the test conditions shown in Table 2. Was tested.

(Table 1)
(Friction and wear test conditions)
Load surface pressure 100 MPa (1020 kgf / cm ² )
Sliding speed 7.83 × 10 ⁻³ m / sec (0.47 m / min)
Swing angle 90 °
Endurance time 100 hours Mating shaft material Induction-hardened chromium molybdenum steel (SMC440)
Motion form Swing motion of the opposite shaft continuous radial journal Lubrication condition Grease before starting the test

(Table 2)
(Fatigue resistance test conditions)
Dimensions of cylindrical bearing (multi-layer sintered sliding member) Inner diameter 30mm, outer diameter 45mm, length
20 mm (pressure receiving area 6 cm ² )
Maximum load 88MPa (898kgf / ^cm 2)
Minimum load 0.2 MPa (2 kgf / cm ² )
Load cycle 20Hz
Test method Cylindrical bearing (pressure-receiving area 6cm ² ) 20 cycles of maximum load and minimum load alternately per second, and the number of cycles until cracks occur in the sintered alloy layer that becomes the sliding surface (maximum 10 million cycles) It was evaluated with.

  Tables 3 and 4 show the test results of the component composition, friction wear characteristics, and fatigue resistance of the multilayer sintered sliding members of Examples and Comparative Examples.

  In Table 4, since the friction coefficient of the multilayered sintered sliding members of Comparative Examples 1 and 2 increased rapidly when the test time exceeded 40 hours in the frictional wear test, the test was stopped at that time. The amount of wear indicates the amount of wear at a test time of 40 hours.

  From the above test results, the multilayer sintered sliding members of Examples 1 to 5 showed a stable sliding with a low coefficient of friction even under high load conditions (100 MPa), and the wear amount was as small as 22 to 28 μm. The friction and wear characteristics are shown. On the other hand, the multilayer sintered sliding member of Comparative Examples 1 and 2 could not achieve the test time of 100 hours under the high load condition, and the test was stopped. Moreover, in the fatigue durability test, the multilayer sintered sliding members of Examples 1 to 5 exhibited 100 times the fatigue durability of the multilayer sintered sliding members of Comparative Examples 1 and 2.

  As described above, the multilayer sintered sliding member according to the example has excellent friction and wear characteristics even under load conditions far exceeding 49 MPa, which is an allowable surface pressure of the conventional multilayer sintered sliding member. It has fatigue resistance and can be applied to applications where high surface pressure acts, for example, a joint bearing of a construction machine such as a toggle bush of an injection molding machine or a hydraulic excavator.

  Next, an embodiment in which the multilayer sintered sliding member is applied to a flat plate-like sliding plate will be described.

  It is an example about Examples 6-7 and the comparative example 3, a flat multilayer sintered sliding member.

Examples 6-7
A steel plate made of general structural rolled steel (SS400) having a width of 170 mm, a length of 600 mm, and a thickness of 5 mm was prepared.

  As the mixed powder, the same mixed powder as in Example 1 and Example 4 was prepared. 0.3 wt% of 5 wt% aqueous HPC solution (100 g of HPC, 120 ml of ethyl alcohol and 1780 ml of water) was added to each of the mixed powders and mixed uniformly with a V-type mixer for 5 minutes to obtain a raw material powder.

The raw material powder is passed through a horizontal rolling roll having twin rolls under conditions of a roll interval of 0.3 mm and a roll speed of 0.3 m / min, and a density 6.8 g / cm ³ and a thickness of 2 mm rolled sheet (molded green compact) ) Was produced. This was cut to a width of 170 mm and a length of 600 mm, and this was overlaid on a steel plate, and then in a sintering furnace adjusted to an ammonia decomposition gas atmosphere, a pressure of 0.7 kgf / cm ² (0.069 MPa) was applied. While being applied, sintering was performed at a temperature of 960 ° C. for 85 minutes. Simultaneously with the sintering of the rolled sheet, diffusion bonding with the steel plate was performed, and a multilayer sliding member in which the sintered alloy layer and the steel plate were diffusion bonded was produced. .

This was machined to obtain a multilayer sintered sliding member having a side of 35 mm and a thickness of 6.5 mm. The density of the porous sintered alloy layer of this multilayer sintered sliding member was 6.9 g / cm ³ . When this multilayered sintered sliding member was subjected to oil impregnation treatment, the oil content of the porous sintered alloy layer was 15% by volume.

Comparative Example 3
A steel plate made of rolled steel for general structure having the same dimensions of 170 mm in width, 600 mm in length and 5 mm in thickness as in Examples 6 to 7 was prepared.

  5% by weight of sprayed Sn powder passing through a 250 mesh screen, 20% by weight of reduced Ni powder passing through a 150 mesh screen, and 7% of ground P-Cu alloy (P15%) powder passing through a 120 mesh screen %, 32% by weight of reduced Fe powder passing through a 300 mesh screen, 5% by weight of natural graphite powder passing through a 48 mesh screen and not passing through a 250 mesh screen, and the remainder passing through a 150 mesh screen Cu powder was put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder (Sn: 5 wt%, Ni: 20 wt%, P: 1.05 wt%, Fe: 32 wt%, natural graphite) : 5% by weight, Cu: balance).

  To this mixed powder, 0.3% by weight of a 5% by weight HPC aqueous solution (same as in the example) was added and mixed uniformly with a V-type mixer for 5 minutes to obtain a raw material powder.

The raw material powder is passed through a horizontal rolling roll having twin rolls under conditions of a roll interval of 0.3 mm and a roll speed of 0.3 m / min, and a rolled sheet (molded green compact) having a density of 5.90 g / cm ³ and a thickness of 2 mm. ) Was produced. This was cut into dimensions of 170 mm in width and 600 mm in length, and this was overlaid on the steel plate.

Next, in a sintering furnace adjusted to an ammonia decomposition gas atmosphere, while applying a pressure of 0.7 kgf / cm ² (0.069 MPa), sintering was performed at a temperature of 940 ° C. for 40 minutes. Thus, a multi-layer sintered sliding member in which the sintered alloy layer and the steel plate were joined and integrated was produced.

This was machined to obtain a multilayer sintered sliding member having a side of 35 mm and a thickness of 6.5 mm. The density of the porous sintered alloy layer of this multilayer sintered sliding member was 6.0 g / cm ³ . When this multilayered sintered sliding member was subjected to oil impregnation treatment, the oil content in the porous sintered alloy layer was 26% by volume.

  Next, the frictional wear characteristics of the multilayer sintered sliding members obtained in Examples 6 to 7 and Comparative Example 3 were tested under the test conditions shown in Table 5.

(Table 5)
(Friction and wear test conditions)
Load surface pressure 100 MPa (1020 kgf / cm ² )
Sliding speed 0.12m / sec (7m / min)
Stroke 80mm
Number of reciprocations 100,000 times Mating material Gray cast iron (FC250) plate Lubrication condition Grease before starting the test

  Table 6 shows the test results of the component compositions and frictional wear characteristics of the multilayer sintered sliding members of Examples 6 to 7 and Comparative Example 3.

  In Table 6, since the friction coefficient of the multilayer sintered sliding member of Comparative Example 3 rapidly increased when the test time exceeded 30 hours, the test was stopped at that time. The amount of wear indicates the amount of wear at a test time of 30 hours.

  From the above test results, the multilayer sintered sliding members of Examples 6 to 7 showed stable sliding with a low coefficient of friction even under high load conditions (100 MPa), and the friction amount was as small as 35 μm or less. The wear characteristics are shown. On the other hand, the multilayer sintered sliding member of Comparative Example 3 was not able to achieve a test time of 100 hours under high load conditions, and the test was stopped.

As described above, in the multilayer sintered sliding member of the present invention, the Ni component forming the porous sintered alloy layer integrally bonded to the back metal diffuses to the surface of the back metal during sintering, and the interface is alloyed. However, to generate a further forming a P component and some liquid phase in the component Cu-Ni-Sn alloy affinity good Ni-P alloy _(Ni 3 P), the Ni ₃ P is back metal and a porous The porous sintered alloy layer is firmly bonded and integrated with the back metal in combination with the alloying by diffusion of Ni component at the interface, and the hard material generated at the time of sintering. Ni ₃ P, which is an intermetallic compound, is intervened in the grain boundary of the Cu—Ni—Sn alloy phase, and the hard high-speed tool steel component composed of fine intermetallic compounds, mainly carbides, is Cu—Ni—. Since it is dispersed and contained in the grain boundaries of the Sn alloy phase and the αFe phase, the porous sintered alloy layer Labor durability, load carrying capacity and friction and wear characteristics are greatly improved, high surface pressure is can be applied to applications that act.

Claims (5)

  3 to 10% by weight of tin component, 10 to 30% by weight of nickel component, 0.5 to 4% by weight of phosphorus component, 30 to 50% by weight of iron component, 1 to 10% by weight of high-speed tool steel component, A multilayer sintered sliding member characterized in that a porous sintered alloy layer containing 1 to 5% by weight of a graphite component and 20 to 55% by weight of a copper component is integrally joined to a back metal.   The multilayer sintered sliding member according to claim 1, wherein the porous sintered alloy layer contains 5 to 20% by volume of lubricating oil.   The multilayer sintered sliding member according to claim 1 or 2, wherein the high-speed tool steel component is selected from one of molybdenum-based high-speed tool steel and tungsten-based high-speed tool steel.   The multilayer sintered sliding member according to any one of claims 1 to 3, wherein the back metal is made of a steel pipe, and the porous sintered alloy layer is integrally joined to the inner surface of the steel pipe. .   The multilayer sintered sliding member according to any one of claims 1 to 3, wherein the backing metal is made of a steel plate, and the porous sintered alloy layer is integrally bonded to the surface of the steel plate.