JPS62235455A - Aluminum bearing alloy and its production - Google Patents

Abstract

PURPOSE:To manufacture an Al bearing alloy lightened in weight and excellent in surface characteristics, by adding specific amounts of Mg powder to an atomized alloy powder of Al - lubricating component - hard component - strengthening component type and by subjecting the resulting mixture to compacting, sintering, and extrusion. CONSTITUTION:The Mg powder is added to the Al - lubricating component - hard component - strengthening component atomized alloy powder by 0.5-1.2wt%, and the mixture is blended and compacted into billet. the above billet then is sintered and further subjected to extrusion at >=10 extrusion ratio. In this way, the lightweight Al bearing alloy combining >=12kgf/mm<2> tensile strength at ordinary temp. with >=11% elongation at ordinary temp. and excellent in fatigue resistance and surface characteristics can be obtained. The above alloy is principally composed of Al and, as the above lubricating component, one or more elements among Pb, Sn, In, Sb, and Bi are finely and uniformly dispersed into the matrix so that the ratio of sectional area to the Al matrix is 0.04-0.07 and the size is <=8mum. Moreover, the above alloy contains Si in 0.02-0.17 ratio of sectional area as the above hard component and, as the above strengthening component, it further contains one or more elements among Cu, Cr, Mn, Ni, Zn, and Fe by 0.2-4.5%.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to materials for bearings and sliding members used as structural parts of various mechanical devices such as automobiles, machine tools, and agricultural machinery. The present invention relates to a bearing alloy suitable for use as a bearing material, and particularly to an aluminum-based bearing base metal that is lighter than copper-based bearing materials and has excellent fatigue resistance and surface performance.

(Prior art) Conventionally, alloys used as materials for sliding bearings contain C.
U-Pb series, Babbitt series, etc. are used depending on the purpose of use, etc., but in recent years, especially as bearing base metals for internal combustion engines, from the viewpoint of heat resistance, wear resistance, corrosion resistance, #fatigue resistance, etc. A
The fL series bearing base metal is attracting attention. Among them, Al-
Since Sn-based and Al-3n-Pb-based bearing base metals are considerably superior to those made of other materials in terms of the above-mentioned performance, their usage has been rapidly increasing recently.

However, due to the miniaturization of internal combustion engines, the width of the bearings has decreased,
As the performance of internal combustion engines increases, such as the increase in bearing load associated with higher output, the demands placed on bearings are becoming even stronger. The current situation is that improvements are desired to suppress this problem.

As an example of an Al-based bearing base metal that can meet the high performance of internal combustion engines, the present inventors have proposed
By applying extrusion processing to the A1-Pb-3n-based atomized alloy powder as shown in the specification of No. 866, we have developed a new type of bearing base metal that has both high fatigue strength and excellent lubricity.

This aluminum-based bearing alloy has Al as its main component, and lubricating components include ib, Sn, In, and Sb.

One or more metals selected from the group consisting of Bi are reinforced with a cross-sectional area ratio of 0.04 to 0.07 to the Al matrix, and Si as a hard component is also reinforced with a cross-sectional area ratio of 0.01 to 0.17. Cu, Cr, Mg, Mn as components
, Ni, Zn.

One or more metals selected from the group consisting of Fe from 0.2 to
5.0% by weight, Ti as a refining component if necessary,
Contains 0.01 to 3.0% by weight of one or more metals selected from the group consisting of B, Zr, V, Ga, and REM (one or more rare earth elements including Sc and Y) based on the total alloy. , a billet formed from an alloy powder in which the size of lubricating components uniformly and finely dispersed is 8 μm or less is extruded at an extrusion ratio of 10 or more, and the size of Si particles dispersed in the All matrix is 12 μm or less, especially Preferably 6-12uL
m, tensile strength at room temperature is 12kg f/mm
It is characterized by an elongation of 2 or more and an elongation at room temperature of 11% or more, and can be used as an Al-based bearing base metal itself, or directly with a steel plate, etc., or with an adhesive layer of Al, Ni, etc. It is characterized in that it can be used as a bearing that is joined through the bearing.

In manufacturing the above aluminum-based bearing alloy, AfL-8 to 12% by weight Pb-0,4 to 1
．． 8% by weight 5n-1,0-15% by weight 5i-0,2-5
．． 0% by weight (Cu.

After heating the alloy powder of one or more of Cr, Mg, Mn, Ni, Zn, and Fe at 350 to 550°C to grow Si particles to a size of 6 to 124 m.

In the alloy powder, Al-10 to 20% by weight Sn-based or Al-1O to 20% by weight 5n-1, 0 to 15% by weight 5
i-0.2 to 5.0% by weight (Cu, Cr, Mg, Mn,
AfL-lubricating components (Pb. one or more of Ni, Zn, Fe), etc.

one or more of Sn, In, Sb, Bi) - hard component (St
) - reinforcing components (Cu, Cr, Mg, Mn.

Ni, Zn, Fe (one or more types of Ni, Zn, Fe) - one or more types of refining components (Ti, B, Zr, V, Ga, REMc7) if necessary) alloy powder so that it falls within the component range of the aluminum bearing base metal. The invention is characterized in that the mixed powder is mixed into a billet, and then the billet is extruded at an extrusion ratio of 10 or more.

Furthermore, in another manufacturing method of the above-mentioned aluminum-based bearing alloy, the lubricating component 9 of the aluminum-based bearing alloy, the reinforcing component and the refining component, are humanities-lubricating components (Pb, Sn, In).

S b , B i c7) 1 or more types) - reinforcing component (
Cu.

one or more of Cr, Mn, Ni, Zn, Fe)-refining components (Ti, B, Zr, V, etc.) as necessary.

one or more of Ga, REM) in the form of atomized alloy powder,
For the hard component, A with a Si particle size of 6 to 12 μm
fL-8 to 30 wt % St atomized alloy powders were used, and both were mixed so as to have the composition range of the aluminum-based bearing alloy, and then the mixed powder was formed into a billet, and then the billet was extruded at an extrusion ratio of 10. This is characterized in that the above is extrusion molded.

(Problems to be Solved by the Invention) The above-mentioned aluminum-based bearing alloy contains Pb and Sn as lubricating components which are soft substances as described above.

Foreign matter embeddability is improved by uniformly and finely containing one or more metals selected from the group consisting of In, Sb, and Bi in a large amount with a cross-sectional area ratio of more than 0.04 and less than 0.07 to the AfL matrix. However, due to the large amount of lubricating components with low melting points, the liquid phase inside the billet becomes large when heated to the extrusion temperature. There is a problem that defects such as edge cracks may occur in the extruded material.

This problem is relatively noticeable when extruding thin plates used as sliding bearing materials, and even in shapes with high extrudability such as round bars, the above defects are likely to occur unless the extrusion speed is relatively reduced. .

This invention was made by focusing on such conventional problems, and it is made by sintering a billet formed from powder to give the billet strength, and then extruding the billet to make an extruded material. The aim is to solve the above problems by eliminating the possibility of defects such as cracked edges.

[Structure of the Invention] (Means for Solving the Problems) The aluminum-based bearing alloy according to the present invention contains AfL as a main component, and Pb and Sn as lubricating components.

One or more metals selected from the group consisting of In, Sb, and Bi have a cross-sectional area ratio of 0.04 to 0.07 with respect to the Al matrix, and Si as a hard component has a cross-sectional area ratio of 0.01 to 0.0. 17 or less, 0.5 to 1.2% by weight of Mg as a sintering accelerating component and reinforcing component, and Cu as a reinforcing component.

0.2 to 4.5% by weight of one or more metals selected from the group consisting of Cr, Mn, Ni, Zn, and Fe, and if necessary, Ti, B, and Zr as finer components.

One or more metals selected from the group consisting of V, Ga, and rare earth elements. A billet formed from a powder containing 1 to 3.0% by weight of O and having uniformly finely dispersed lubricating components with a size of 84 m or less is extruded at an extrusion ratio of 10 or more.
The size of the Si particles dispersed in the matrix is 12
μm or less, a tensile strength at room temperature of 12 kgf/mm2 or more, and an elongation at room temperature of 11% or more.

In addition, the method for producing an aluminum-based bearing alloy according to the present invention includes an Al-lubricating component (pb) when producing the above-mentioned aluminum-based bearing alloy.

one or more of Sn, In, Sb, Bi) - hard component (Si
) - reinforcing components (Cu, Cr, Mn, Ni).

0 to atomized alloy powder of one or more types of Zn, Fe)
．． 5 to 1.2% by weight of Mg powder is added and mixed, the mixed powder is formed into a billet, the billet is sintered, and the sintered billet is extruded at an extrusion ratio of 10 or more. This is a characteristic feature.

The reasons for limiting each component and numerical value will be explained below.

(1) Pb, Sn, In, Sb, and Bi are effective as cutting components and have excellent seizure resistance. but,
If the total amount of lubricating components is less than 0.04 in terms of cross-sectional area ratio (volume ratio), the foreign matter embedding property will be poor, and if it exceeds 0.07, the fatigue strength of the matrix will be insufficient, which will affect the bearing performance in terms of load resistance. You won't be satisfied.

Furthermore, the particle size of the lubricating component is preferably 84 m or less, since excessive particle size will adversely affect the performance of the bearing base metal.

(2) St is added as a hard component, and Al1. As a hard substance, it contributes to improving bearing strength and wear resistance. The amount of Si to be added is preferably from 1/4 to 2.5 times the amount of the lubricating component in terms of cross-sectional area ratio (volume ratio).
The cross-sectional area ratio to the matrix is 0.01 or more and 0.17
The following is desirable.

Regarding the Si particle diameter, it is preferable to set it to 12 pm because if it exceeds 12 pm, it will damage the mating material and reduce the areal density of the dispersion and deteriorate the wear resistance.

(3) Mg is an essential component in this invention.

This Mg is an effective component for increasing the strength of the AfL matrix, and in the present invention, it is also a sintering activating element when sintering the powder compact. At that time, 0.
If it is less than 5%, the above effects cannot be expected, and if it is less than 1 or 2%.
If it exceeds this amount, a large amount of liquid phase containing Mg will be produced during extrusion, which will actually reduce extrudability.

Furthermore, in the manufacturing method of the present invention, Mg is not used as an alloy powder but is added and mixed as a pure powder.

The reason for this is that during sintering, a eutectic liquid phase with Al is present not within the alloy powder but at the powder grain boundaries, thereby activating sintering.

(4) Cu, Cr, Mn, Ni, Zn, and Fe are effective components for increasing the strength of the A sentence matrix. Among these, Cu is a main element that increases creep strength, that is, high-temperature softening resistance, and contributes to improving fatigue resistance under high-temperature sliding. However, if it is less than 0.2% by weight, the above-mentioned effect is small, and if it exceeds 4.5% by weight, acicular CuAf
A large amount of L2 compound precipitates and becomes brittle, leading to a decrease in fatigue resistance.Also, as an element other than Cu that increases the strength of the matrix, Cr * M n + N L I Z
n.

Fe is often used as an additive element for A1 alloy wrought material, and one or more of these elements including Cu are
．． It may be added in an amount of 2 to 4.5% by weight.

(5) Ti, B, Zr, V, Ga, rare earth elements (RE
M; one or more rare earth elements including Y and Sc) is effective as a grain refining agent for A pattern alloys, and promotes uniform refining of the lubricating component (soft substance), which is the gist of this invention. It is also desirable to add in a range of 0.01% by weight or more and 3.0% by weight or less, if necessary.

(6) Regarding the sintering temperature, it is possible to appropriately select a temperature that can strengthen the billet sufficiently to prevent the occurrence of defects in the extruded material and that does not cause coarsening of Si, which is a lubricating component and a hard component, but the preferred temperature is is 530℃~550℃
It is C.

(7) Regarding the extrusion ratio, if the extrusion ratio is less than 10, internal cracks and surface cracks of the bearing base metal material after extrusion will occur, and it is difficult to obtain a material suitable for practical use, so the extrusion ratio was set to 10 or more.

(Example 1) In weight%, Pb: L2.0%, Sn: 3.0%, Si
: 4.0%, Cu: 0.75%, Cr: 0.5%, and the remainder substantially consists of AIL and impurities. Mg powder = 0.5% by weight is added and mixed, and the mixed powder is Diameter 170mm.

A billet was formed into a cylindrical shape with a length of 200 mm by cold isostatic pressing at a hydrostatic pressure of 2.0 tonf/cm 2 .

Next, the billet was heated at 550'C! in a nitrogen atmosphere. After that, the sintered billet was cooled to 400°C and extruded at a product extrusion speed of 3.0 m/min to obtain a plate-shaped extruded body with a thickness of 2 mm and a width of 120 mm. .

In this extruded product, the cross-sectional area ratio of the lubricating component to the Al matrix was 0.045. The size of the lubricating component is 8
μm or less, the cross-sectional area ratio of Si to Al matrix is 0.047, and the size of Si particles is 6 to 124
It was m.

In addition, the tensile strength of the extruded material is 19.2 kgf/mm2,
The elongation was 15.5%.

(Comparative Example 1) In weight%, Pb: 12.0%, Sn: 3.0%, Si:
2. Aluminum alloy powder consisting of 4.0% Cu, 0.75% Cu, 0.5% Cr, and the remainder substantially AfL and impurities was shaped into a cylinder with a diameter of 170 mm and a length of 200 mm.
A billet was formed by cold isostatic pressing at a hydrostatic pressure of 0 tonf/cm2.

Next, the billet was extruded at 400°C at a product extrusion rate of 3.0.
Extrusion processing was carried out at a speed of m/min to obtain a plate-shaped extruded product having a thickness of 2 mm and a width of 120 mm, but edge cracks occurred in the extruded material.

(Comparative Example 2) In weight%, Pb: 12.0%, Sn: 3.0%, Si:
4.0%, Cu: 0.75%, Cr: 0.5%, M
g: 0.5%, the remainder consisting essentially of A and impurities, aluminum alloy powder with a diameter of 170 mm and a length of 200 m.
A billet was formed by cold isostatic pressing at a hydrostatic pressure of 2.0 tonf/cm 2 into a cylindrical shape of m.

Next, the billet was extruded at 400°C at a product extrusion speed of 3.0 m.
/min to obtain a plate-shaped extruded product having a thickness of 2 mm and a width of 120 mm, but edge cracks occurred in the extruded material.

As is clear from the comparison between Example 1 and Comparative Examples 1.2, by using the manufacturing method according to the present invention, it becomes possible to extrude thin plates and extrude at high speeds, which was impossible with conventional methods.

It should be noted that even with the alloy powder shown in Comparative Example 1.2, defects can be avoided by changing the shape of the extruded material to a shape with better extrudability, such as a thick plate or round bar, or by lowering the extrusion speed to around 1.0 m/min. It is possible to obtain extruded materials without

(Example 2) In weight%, Pb: 9.6%, Sn: 3.0%, Si: 4
．． 0%, Cu: 0.75%, Cr: 0.5%, Zr: 0
．． Mg powder = 1.0% by weight was added and mixed to an aluminum alloy powder consisting of 0.5% and the remainder substantially AfL and impurities, and the mixed powder was formed into a columnar shape with a diameter of 170 mm and a length of 200 mm. A billet was formed by cold isostatic pressing at a hydrostatic pressure of cm2.

Next, the billet was sintered at 550°C for 2 hours in a nitrogen atmosphere, and then the sintered billet was cooled to 350°C and extruded at a product extrusion speed of 3.0 m/min. 2
A plate-shaped extrusion molded body having a width of 120 mm and a width of 120 mm was obtained.

In this extruded product, the cross-sectional area ratio of the lubricating component to the AM matrix is 0.040, and the size of the lubricating component is 8.
pm or less, the cross-sectional area ratio of Si to Al matrix is 0.047, and the size of Si particles is 6 to 12I.
It was Lm.

Moreover, the tensile strength of the extruded material is 21. Okgf/mm2,
The elongation was 13.2%.

(Comparative Examples 3 to 5) Here, alloys having different amounts of added components from the alloy according to the present invention were manufactured as comparative alloys.

That is, aluminum alloy powder having each composition shown in Table 1 was cold isostatically formed into a cylindrical shape with a diameter of 170 mm and a length of 200 mm (7) under a hydrostatic pressure of 2.0 tonf/cm 2 to form a billet.

Next, the billet was fired at 550°C for 2 hours in a nitrogen atmosphere, and then the fired billet was extruded at 400°C at a product extrusion speed of 2.0 m/min, with a thick gauge of 1 Jυ and 1 square. Using the extrusion molded bodies of Example 1.2 and Comparative Examples 3 to 5, in which plate-shaped extruded materials were obtained, the extrusion molded body → heat treatment before rolling → rolling → annealing → pre-cladding with a pure aluminum plate → annealing. → The bearing was manufactured through the process of cladding with steel plate → annealing → machining.

Next, the produced bearings were subjected to a severe bearing fatigue test as shown in Table 2. Table 2 Bearing fatigue resistance test conditions As is clear from FIG. 1, Example 1 according to the present invention.
It can be seen that the bearings of No. 2 have superior durability compared to the bearings of Comparative Examples 3 to 5, which are conventional materials.

[Effects of the Invention] As explained above, the aluminum-based bearing alloy according to the present invention contains Al as a main component and Pb as a lubricating component.
, Sn, In, Sb, and Bi at a cross-sectional area ratio of 0.
04 or more and 0.07 or less, Si as a hard component with a cross-sectional area ratio of 0.01 or more and 0.17 or less, 0.5 to 1.2% by weight of Mg as a sintering accelerating component and a reinforcing component, and Cu as a reinforcing component. , Cr, Mn, Ni, Zn.

One or more metals selected from the group consisting of Fe from 0.2 to
4.5% by weight, Ti and B as finer components if necessary
, Zr, V, Ga, and rare earth elements. A billet formed from powder containing 1 to 3.0% by weight of O and having uniformly finely dispersed lubricating components having a size of 8 μm or less is extruded at an extrusion ratio of 10 or more.

The size of the Si particles dispersed in the Al matrix is 12
pm or less, a tensile strength at room temperature of 12 kgf/mm2 or more, and an elongation at room temperature of 11% or more. In manufacturing aluminum-based bearing alloys, AM-lubricating components (Pb, Sn, In,
Sb.

one or more types of Bi) - hard component (Si) - reinforcing component (Cu
* Cr 1M n + N i + Z n + F
e (1) 0 to the atomized alloy powder of one or more types)
．． 5 to 1.2% by weight of Mg powder is added and mixed, the mixed powder is formed into a billet, the billet is sintered, and the sintered billet is extruded at an extrusion ratio of 10 or more. It is possible to provide an excellent lightweight bearing alloy with unprecedentedly high levels of both fatigue resistance and surface performance (lubrication performance), which are contradictory properties. By using the improved manufacturing method of this invention, it is possible to extrude thin plates used as materials for sliding bearings, which was impossible with conventional methods, so it has an extremely wide range of applications. is brought about.

[Brief explanation of drawings]

FIG. 1 is a graph showing the results of a fatigue resistance test conducted on a bearing according to the present invention and a conventional bearing. Patent applicant: Nissan Motor Co., Ltd. Applicant: NDC Co., Ltd., agent and patent attorney
Yutaka Ko Shio Figure 1 Endurance time th? sJ

Claims (3)

[Claims] (1) Al is the main component, and one or more metals selected from the group consisting of Pb, Sn, In, Sb, and Bi are used as a lubricating component, with a cross-sectional area ratio of 0.04 to 0.07 to the Al matrix; Si as a hard component, with a cross-sectional area ratio of 0.01 to 0.17; Mg as a sintering accelerating component and reinforcing component, 0.5 to 1.2% by weight;
As a reinforcing component, one or more metals selected from the group consisting of Cu, Cr, Mn, Ni, Zn, and Fe are added at 0.2 to 4.5
% by weight, the size of the lubricating component uniformly and finely dispersed is 8.
A billet molded from powder with a particle diameter of less than μm is extruded at an extrusion ratio of 10
The above is extrusion molded, and the size of the Si particles dispersed in the Al matrix is 12 μm or less, the tensile strength at room temperature is 12 kgf/mm^2 or more, and the elongation at room temperature is 11% or more. Aluminum-based bearing alloy. (2) Ti and B as fine components in the Al matrix
, Zr, V, Ga, and rare earth elements in an amount of 0.01 to 3.0% by weight. Aluminum bearing alloy. (3) Al as a main component, and one or more metals selected from the group consisting of Pb, Sn, In, Sb, and Bi as a lubricating component, with a cross-sectional area ratio of 0.04 to 0.07 to the Al matrix; Si as a hard component, with a cross-sectional area ratio of 0.01 to 0.17; Mg as a sintering accelerating component and reinforcing component, 0.5 to 1.2% by weight;
As a reinforcing component, one or more metals selected from the group consisting of Cu, Cr, Mn, Ni, Zn, and Fe are added at 0.2 to 4.5
% by weight, the size of the lubricating component uniformly and finely dispersed is 8.
When manufacturing an aluminum-based bearing alloy with a diameter of less than μm, the following ingredients are used:
, Mn, Ni, Zn, Fe) system atomized alloy powder, 0.5 to 1.2% by weight of Mg powder is added and mixed, the mixed powder is formed into a billet, and the billet is sintered. A method for producing an aluminum-based bearing alloy, characterized in that the sintered billet is extruded at an extrusion ratio of 10 or more.