JPS6237337A - Bearing alloy - Google Patents

Abstract

PURPOSE:To render a high level of fatigue resistance and surface performance as a bearing by subjecting a billet formed of alloy powder prepd. by dispersing an adequate ratio each of a lubricating component, hard component, lipophilic component, reinforcing component, etc. into an Al matrix to extrusion processing. CONSTITUTION:>=1 Kinds among Pb, Sn, In, Sb and Bi are incorporated as the lubricating component into the Al matrix at 0.006-0.004 ratio by cross sectional area. Si is incorporated as the hard component therein at 0.003-0.060 ratio likewise by cross sectional area. Zn is incorporated as the lipophilic component therein at over 5.0-10.0wt%. >=1 Kinds among Cu, Cr, Mg, Mn, Ni and Fe are incorporated as the reinforcing component therein at 0.2-5.0%. The size of the dispersed lubricating component is made <=8mum. The billet is molded from such Al alloy powder and is subjected to extrusion processing at >=10 extrusion ratio. The size of the Si particles dispersed into the matrix of such bearing alloy is <=12mum and the tensile strength thereof at an ordinary temp. is >=15kgf/mm<2>. The elongation is >=8%. The alloy is light weight and excels in both characteristics of the fatigue resistance and surface performance.

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 bearing alloys suitable for use as bearing alloys, and particularly to aluminum-based bearing base metals that are considerably lighter than copper-based materials and have excellent fatigue resistance, surface performance, etc.

(Prior art) Conventionally, alloys used as materials for sliding bearings contain C.
U-Pb series, Babbitt series, etc. are used depending on the required environment, but AU series is especially used as a bearing base for internal combustion engines due to its heat resistance, corrosion resistance, and fatigue resistance. bearing alloys are attracting attention. Among them, An-
Since bearing base metals of 5n series and AU-5n-Pb series are superior to other materials in terms of the above-mentioned performance, their use has rapidly increased in recent years. However, as the performance of internal combustion engines increases, such as reduction in bearing width due to miniaturization of internal combustion engines and increase in bearing load due to higher output, demands placed on bearings become even stronger. In other words, cracks in the bearing alloy or localized cracks from the steel backing metal! The reality is that improvements are desired to suppress A-chicks.

The present inventors have been conducting various researches in order to meet these demands, and for example, we first developed an AL method using a powder extrusion method.
; Developed L series bearing alloy (Patent application 13224/1989)
No. 9).

This bearing alloy has A as a main component and P as a lubricating component.
1 selected from the group consisting of b, Sn, In, Sb, Bi
Metals with a cross-sectional area ratio of 0.006 or more and 0.040 or less with respect to the AQ matrix, and St as a hard component with a cross-sectional area ratio of 0.003 or more J: 0.0
60 pieces, Cu, Cr, Mg, Mn, N as reinforcing ingredients
i.

It contains 0.2% by weight or more and 5.0% by weight or less of one or more metals selected from the group consisting of Zn, and is uniformly and finely dispersed. ! ¥1 It is made by extruding a billet formed from an alloy powder in which the size of the lubricating component is 8 μm or less at an extrusion ratio of 10 or more.

This AL;L bearing base metal has excellent strength and elongation, and is considerably lighter than a copper bearing base metal, yet has the tradeoffs of fatigue resistance and surface performance (lubrication performance). This is an extremely superior bearing base metal that has both properties that are at unprecedented levels.

(Problems to be Solved by the Invention) The above-mentioned AU bearing base metal has excellent characteristics in both fatigue resistance and lubrication performance as described above, but the lubricating oil film is extremely thin. If the lubricating oil is running at low speed and under high load, or if the lubricating oil temperature is high, there is a risk of slight seizure.

To prevent such seizure, a component with excellent seizure resistance (Pb
One method is to increase the content of (Sn, Sn, etc.), but this has the disadvantage of causing insufficient strength and high-temperature softening.It is possible to increase the oil drain limit without causing insufficient strength or high-temperature softening. development was desired.

(Object of the Invention) This invention was made in view of such a demand, and uses Pb as a lubricating component which is a soft substance.

It contains a large amount of one or more metals selected from the group consisting of Sn, In, Sb, and Bi in a uniform and fine manner, and also contains a large amount of Zn, which has excellent lipophilicity.

Furthermore, by extruding a billet formed from alloy spray powder that has an active ingredient as a bearing alloy, the oxide film on the surface of the powder particles is dispersed into pieces, which also produces the effect of improving heat resistance like SAP, and By creating a bearing alloy with firmly fixed particles, we have achieved unprecedented levels of antinomian performance in bearings, namely fatigue resistance and surface performance (lubrication performance). The object of the present invention is to provide an AU-based bearing alloy that does not cause minute seizures even in cases where such seizures occur.

[Structure of the Invention] (F Stage for Solving Problems) The bearing base metal according to the present invention has Al as a main component, and Pb, Sn, In, and Sb as lubricating components.

A! One or more metals selected from the group consisting of Bi! ;L
Cross-sectional area ratio to matrix of 0.006 or more and 0.04
0 or less, Si as a hard component also has a cross-sectional area ratio of 0.0
03 or more and 0.060 or less, Zn as a lipophilic component 5.0
More than 10.0% by weight 1 Cu as a reinforcing component,
Cr, Mg.

Contains 0.2% by weight or more and 5.0% by weight or less of one or more metals selected from the group consisting of Mn, Nf, and Fe, and optionally includes Ti and B as finer components.

Zr, V, Ga and rare earth elements (REM.

Contains 1% or more and 3.0% by weight or less of one or more metals selected from the group consisting of Sc, Y, and one or more rare earth elements (including one or more rare earth elements, including A billet formed from an alloy powder in which the size of dispersed lubricating components is 8 μm or less is extruded at an extrusion ratio of 10 or more, and the size of Si particles dispersed in the An matrix is 12 μm or less,
Tensile strength at room temperature is 15 kgf/IIn? As mentioned above, it is characterized by an elongation of 12% or more at room temperature, and A
It can be used as a 2-system bearing base metal itself, or it can be used as a bearing in which the bearing base metal layer is bonded to a steel plate or the like directly or through an adhesive layer of Al, Ni, etc.

The composition of the bearing alloy according to the present invention is within a range that can exhibit better bearing performance than conventional bearings for the first time by introducing an extrusion molding method, and extrusion molding may be performed if the components are outside the scope of the claims. It is difficult to expect synergistic effects.

Here, A! used in the bearing alloy according to the present invention! ; L alloy powder will be explained.

(1) Pb, Sn, In, Sb, and Bi are effective as lubricating components and have excellent burn resistance. Among these, Pb is a cast material with a cross-sectional area ratio of 0.005 or less to the An matrix, which does not cause segregation.However, as mentioned above, in the atomization method, a large amount of Pb is contained uniformly and finely. In order to exhibit the lubricating performance of the bearing alloy, the cross-sectional area ratio must be 0.006 or more.In addition to Pb, the lubricating component Sn
If the total amount of , In, Sb, and Bi exceeds 0.040 in terms of the cross-sectional area ratio to the AL;L matrix, bearing performance cannot be satisfied in terms of load capacity. ! ? Ingredients are 0.
On the other hand, Sn improves the surface performance by coexisting with Pb, and also improves the corrosion resistance of Pb. In addition, although In has the same effect as Sn, it is expensive, so it is practically preferable to limit its addition to a small amount.Furthermore, although Sb and Bi contribute to fine dispersion of Pb and Sn, Pb and Sn addition needles 0.1-8
．． It is more desirable to keep the particle size within the range of 5% by weight. Furthermore, if the particle size of the lubricating component is too large, it will have a negative effect on the performance of the bearing alloy, so it is preferably 8 μm or less.

(2) Si is added as a hard component, and A! ; Dispersed in L, N'f is dispersed as a hard substance on the bearing strength side and the wear resistance side.
- to do. The amount of Si to be added is preferably about half to 1.5 times the amount of the lubricating component.Adding too much will make it hard and brittle, impeding workability. It is preferable that the maximum diameter of the Si particles be in the range of 0.003 or more and 0.060 or less.In addition, if the maximum diameter of the Si particles increases, it will damage the mating material, reduce the areal density of dispersion, and deteriorate the wear resistance. The maximum diameter of should be suppressed to 12 μm or less.

(3) Cu, Cr, Mg, Mn, Ni, and Fe are effective components for increasing the strength of the An matrix. Among these, Cu is the main element that increases creep strength, that is, high temperature softening resistance, and is it effective for improving fatigue resistance under high temperature sliding conditions? i' Goo. However, if it is less than 0.2% by weight, the above-mentioned effect will be small, and if it exceeds 5.0% by weight, acicular CuA interaction will occur.

Elements other than Cu that increase the strength of the An matrix include Cr, Mg, and Mn.

Ni and Fe are often used as additive elements for An alloy wrought materials, and one or more of these elements including Cu are added in a total amount of 0.2% to 5.0% by weight. (4) Zn is the above-mentioned C u , Cr , M g
.

As with Mn, Ni, and Fe, A! ; It is an effective component for increasing the strength of the L matrix. This Zn is a component that can significantly strengthen the An matrix by the action of MgZn2 precipitates, especially when coexisting with Mg. Furthermore, the addition of Zn has a large affinity with lubricating oil and is extremely effective in preventing oil film breakage. In this case, when the amount of Zn added is less than 5.0% by weight, this lipophilic effect is small, and 1.
0. If the Oi amount% is exceeded, the hardness will increase and workability will be inhibited, so it is preferable to keep the Zn in the range of more than 5.0% by weight and 10.0% by weight or less. Some Cu, Cr, Mg, Mn, Ni.

It is also possible to expect a synergistic effect by coexisting with Fe.

(5) Ti, B', Zr, V, Ga, and REM (
One or more rare earth elements including Y and Sc, h) are effective as grain refiners for A1 alloys, and are used to promote uniform refinement of lubricating components (soft substances), which is the gist of the present invention. , 0.01% by weight or more 3.0% by weight as necessary
It is also desirable to add in the following range.

Before determining the above components, the present inventors extruded a mixture of individual powders having these compositions or a mixture of partially alloyed powder and individual powder, but the surface defects of the extruded material and the internal powder Cracks occurred at the grain boundaries, and as a result, by using the completely alloyed powder having the above composition, a completely extruded body was obtained. This is because the hardness of each powder particle containing the above-mentioned effective elements is more homogeneous than in the case of mixed powder, and when such powder particles are extruded, surface oxidation due to friction between powder particles occurs. It is assumed that this is because the destruction of the film and the metal bonding occur continuously.

(Example) Next, examples of the present invention will be described together with comparative examples.

Table 1 shows the alloy powder composition used here.

First, in an electric melting furnace at 950'C to 1000°C, Table 1
Each alloy was melted to have a composition of 100 mm in diameter, and an alloy powder with a particle size of 118 mesh was obtained by air atomization.
A cylindrical shape with a length of 100 mm was subjected to cold fin isostatic pressing at a hydrostatic pressure of 2 tonf/cm 2 to form a billet, and this billet was used as a material before extrusion. It has been found that the method of directly extruding two alloy powders causes surface cracks, internal defects, etc., and is difficult to obtain for practical use. Furthermore, according to the present inventors, direct extrusion of powder did not yield a healthy product even when the extrusion ratio was set to 20 or more. Therefore, it is necessary to prepare the alloy powder as a material before extrusion by first solidifying it into a billet shape by cold isostatic pressure or molding.

Next, the billet-shaped material before extrusion is extruded at a temperature of 250.
Forward extrusion was carried out at an extrusion ratio of 40 at a temperature of 550°C to 550°C to obtain various extruded bodies. Then, the mechanical properties during extrusion, that is, the tensile strength and elongation of each extruded body were measured, and the results shown in Table 1 were also obtained.

Various methods and equipment are being considered for extrusion, but the forward-extrusion method using a vertical or horizontal extruder is preferred because of its high productivity, ease of equipment maintenance, and the ability to easily obtain stable quality. Axial extrusion is preferred. Further, the extrusion temperature affects the hardness of the molded product after extrusion, the extrusion speed, and the extrusion ratio, but the soundness of the extruded product is substantially determined by the extrusion ratio. In other words, in the case of a component combination that is difficult to extrude, the extrusion temperature can be increased by
When the extrusion ratio exceeds 20, the surface cracks and internal cracks are significantly reduced north of 0, and there are no cracks in any composition when the extrusion ratio exceeds 20. The upper limit of the extrusion ratio should be set as long as molding is possible and in relation to equipment capacity, etc., and in the present invention, setting the upper limit is unnecessary.

On the other hand, if the composition is outside the ingredients of this invention, if it is a mixed powder even if it is included in the ingredients of this invention, or if the extrusion ratio is less than 10, cracking will occur, resulting in complete extrusion. It was confirmed that it was difficult to obtain a molded body.

(Manufacturing Example) Next, to explain an example of manufacturing a bearing, Fig. 1 is a process diagram adopted to manufacture a bearing. Extrusion molding, followed by pressure welding preliminary heat treatment as necessary.
The bearing is then subjected to pressure welding and annealing treatment.

5. An alloy having a composition of 5 is melted at a melting temperature of 950°C to 1000°C, and an alloy powder having a particle size of 118 mesh is produced from this molten alloy by an air atomization method, and then this alloy powder is subjected to cold isostatic pressure. A billet molded body with a diameter of 100 mm and a length of 100 mm was produced by pressure molding at 2 tonf/cm'6.Then, this billet molded body was extruded at a temperature of 400 mm.
C. and an extrusion ratio of 80 to obtain a plate-shaped extrusion molded product having a width of 60 mm and a thickness of 1.8 mm.

Next, a pure aluminum thin plate with a width of 62 mm and a thickness of 0.4 mm was pressure-welded to this compact to obtain a two-layer bearing alloy plate with a thickness of 1.2 mm.
The alloy was softened to Hv53 by applying a 7-hour anneal treatment, and the alloy was press-welded to a roughened steel plate with a thickness of 2 mm, and then roll-press welded to a thickness of 1.8 mm.

After the pressure bonding, an annealing treatment was performed at 400° C. for 6 hours. Thereafter, when the distribution of the soft substance was examined using an electron microscope, it was found that the soft substance was uniformly and finely dispersed, and the size of the soft substance, which is a lubricant component, was within 874 m.

In addition, as a method for pressure-welding the alloy plate and the steel plate, in addition to the method of using the A pattern thin plate as the adhesive layer, there are also methods of omitting the adhesive layer,
There are methods such as using Ni plating for the adhesion layer, but the appropriate process should be selected from the viewpoints of bearing alloy composition, construction method, economic efficiency, etc., and other materials (for example, An powder, Cu
There is no problem with applying heat treatment to the extrusion molded product before pressure welding. It can be made even larger.

Next, in order to examine the surface performance of the An-based bearing alloy having the composition shown in Table 1, samples (35 x 35 mm) were cut out from the material after the annealing treatment described in the above manufacturing example.
A friction test was conducted under the conditions shown below. The results are shown in FIG.

Table 2 Friction test conditions As is clear from the results shown in Figure 3, the bearing alloy according to the present invention (1'o, 3, 6.11) is superior to the conventional bearing alloy (No. 13) shown for reference. It has excellent surface performance.

Next, each extrusion molded body shown in Table 1 was pressed against a steel plate and annealed, and then a bearing was manufactured from the bearing alloy by machining known in the industry, and subjected to a severe bearing fatigue resistance test as shown in Table 3. went. The results are shown in FIG.

Table 3 Bearing fatigue resistance test conditions As shown in FIG.
It can be seen that bearing No. 12) has excellent fatigue resistance not found in conventional bearings (Nos. 13 to 18) and has a long durability.

[Effects of the Invention] As explained below, the bearing alloy according to the present invention has the following effects:
The main component is Al, and the main components are Pb, Sn, and In.
, Sb, and Bi, with a cross-sectional area ratio of 0.006 to 0.0 with respect to Al trix.
40 or less, Si as the hard component is also 0.40 or less in cross-sectional area ratio.
003 to 70, 060 and below, Zn as a lipophilic component 5.
Over 0 weight h2% and below 10.0 weight h2%, C as a reinforcing ingredient
0.2% by weight or more and 5.0% by weight of one metal selected from the group consisting of u, Cr, Mg, Mn, Ni, and Fe.
Contains the following, with Ti and B as finer components if necessary
, Zr, V', Ga, and REM, containing 0.01% to 3.0% by weight of one or more selected from the group consisting of Zr, V', Ga, and REM, and the size of the lubricating component uniformly and finely dispersed is 8#. It is made by extruding a billet formed from an alloy powder having a particle size of Lm or less at an extrusion ratio of 10 or more, and Si dispersed in an An matrix.
Particle size is 12 μm or less, tensile strength at room temperature is 15
kgf/lIrm2 or more, the elongation at room temperature is more than 12%, and it has excellent strength and elongation. It is also considerably lighter than copper-based bearing materials, and has excellent fatigue resistance and surface performance (lubrication). Both of the antinomic characteristics of bearings (performance) are at an unprecedentedly high level, and the lubricating oil film becomes extremely thin and oil runs out, especially when rotating at low speeds and under high loads or when the lubricating oil temperature is high. This bearing alloy has the remarkable effect of being resistant to minute seizures even in cases where it is easily damaged, and is a bearing alloy with extremely excellent properties that have a high oil drain limit.

[Brief explanation of the drawing]

Figure 1 is a block explanatory diagram showing an example of the manufacturing process of bearings, Figure 2
The figure is an explanatory diagram showing the load pattern during the friction test, Fig. 3 is a graph showing the friction test results, and Fig. 4 is an explanatory diagram showing the results of the fatigue resistance test of the bearing according to the present invention and the conventional bearing. be. Patent applicant: Nissan Motor Co., Ltd. Applicant: NDC Co., Ltd., agent and patent attorney
Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Al as the main component, Pb, 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 0.006 to 0.040 with respect to the Al matrix, and Si as a hard component has a cross-sectional area ratio of 0.003 to 0.0. 060 or less, Zn as a lipophilic component
more than 5.0% by weight and not more than 10.0% by weight, and 0.2% by weight or more of one or more metals selected from the group consisting of Cu, Cr, Mg, Mn, Ni, and Fe as reinforcing components. % by weight or less, and the size of the lubricating component uniformly and finely dispersed is 8 μm or less, and the billet is extruded at an extrusion ratio of 10 or more, and the size of the Si particles dispersed in the Al matrix is is 12μm or less, tensile strength at room temperature is 15kgf/mm^2 or more, and elongation at room temperature is 12
% or more. (2) Ti, B, as fine components in the Al matrix
Claims characterized in that the alloy contains at least 0.01% by weight and not more than 3.0% by weight of one or more metals selected from the group consisting of Zr, V, Ga, and rare earth elements. The aluminum-based bearing alloy according to item (1).