JPH0347934A - Al-sn-pb series bearing alloy - Google Patents

Abstract

PURPOSE:To improve the seizure resistance and wear resistance of the bearing alloy by adding a specified amt. of Sr to an Si-contg. Al-Sn-Pb series alloy having specified compsn. and regulating the shape of Si to a spheroidal one. CONSTITUTION:The bearing alloy is constituted of, by weight, 3 to 35% Sn, 0.1 to 11% Si, 0.1 to 10% Pb, 0.1 to 2% of one or more kinds among Cu, Mg and Zn, 0.1 to 1% of one or more kinds among Cr, Mn, Fe, Ni, Co, Mo, Sb, V and Zr, 0.01 to 0.3% Sr and the balance Al. Furthermore, in the Al matrix 1, Si grains 2 having a spheroidal or elliptical shape or a roundish shape in the tip are dispersed and precipitated. By the grains 2, the ideal of the point contact can nearly be obtd. to moreover increase the lubricity and wear resistance. Moreover, even if high-speed and rapid high loads are applied, the alloy does not flaw the mating shaft and the matrix 1 has no notch effect therein as well as has stabilized strength and excellent wear resistance. Furthermore, Sn-Pb alloys 3 are present more adjacently to the grains 2, by which the lubricity can drastically be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an AI-3n-Pb bearing alloy, and more specifically, the present invention relates to an A I-3n-Pb bearing alloy. Particles tend to be dispersed and precipitated (1).Excellent during high-speed/high-load operation.
Among these, it relates to a Δl -SnPb bearing base metal having high fatigue resistance and seizure resistance.

Conventional technology Modern automobile engines have become smaller, more fuel efficient, and have higher output, which has resulted in an increase in the load on the bearings and an increase in the temperature of the lubricating oil, making it difficult to use the bearings. Conditions are becoming more and more severe. Most of the conventional multi-component type and AI type shaft bearings have a surface layer of P b -3n type or the like formed on the surface of the bearing base metal part by overlay plating or the like. However, bearings with this structure suffer from "fatigue" and "burning" phenomena due to high temperatures on the wet surface, making them unable to withstand the harsh operating conditions mentioned above. So recently,
There is a need for bearings that do not have a surface layer formed by overlay plating or the like. However, the current situation is that even this type of bearing cannot necessarily exhibit stable performance under the above-mentioned severe usage conditions.

(2) That is, a bearing with an overlay on the surface has - JIS H5402, Δ, 1-1F10 inside the membrane.
%Sn, 0.75%CLJ, 0.5%Ni, Al1B
a/), JIS H5402, AJ-2 (6%Sn
, 2.5% Cu, 1.0% N i , AIBan, etc.
IS standard, 5AF780 (6%Sn, 2%S1.1%C
As shown in the SAE standards such as l, 0.5%N+, 0.1%Ti, Al113a1, etc., the bearing base metal part is made of a low 3n-A1 alloy with relatively little 3n content. A surface layer is further formed on the surface of the alloy portion by overlay plating of a Pb-3n alloy, and this surface layer constitutes a bearing surface. However, under recent high-load, high-temperature operating conditions, the surface layer of these bearings due to overlay plating on the surface wears out, leading to seizure, making them unusable. On the other hand, bearings that do not have a surface layer formed by overlay plating on the surface are SAE
783 (20%Sn, 0.5%S1.1.O%CLI
, 0.1%T(3) A'It B a It l As shown in , the bearing base metal portion is made of a high 3n-A1 alloy with a high Sn content. However, alloys containing as much as 20% of this J: sea urchin 3n have low hardness, and Aj? The matrix becomes weak and cannot withstand high loads.

Furthermore, irrespective of the amount of 3n content, l)b is added to the Al-Sn alloy to improve lubricity and provide a bearing base metal with anti-f-J properties, for example, as reported by Akira Mizuno, published in 1950, Nikki. It is described in "Bearing Alloy" published by Kogyo Shinbunsha, page 139, and this bearing base metal is made of Al-3n- containing 10% Sn, 1.5% Cu, 0.5% 3i, and 3% Pb added. Pbb
There are alloys.

Furthermore, since Pb in the Al-Sn-Pb base metal hardly forms a solid solution with All, an Al-SnPb-sb alloy containing sb to improve the dispersibility of Pb was developed in Japanese Patent Publication No. 52-12131. A'l-Sn-Pb with cr added to strengthen the Al matrix.
(4) Sb-Or alloys are described in Japanese Patent Publication No. 58-18985. However, these AJSn-pb alloys were developed for the purpose of improving lubricity during normal operation, and have the drawback of not exhibiting sufficient fatigue resistance under high-load operating conditions.

The reason for this is that the lubrication mechanism between the shaft and bearing under high load operation is fundamentally different from that under normal operation.

Recently, a basic examination84 was carried out on the differences between the lubrication mechanism under high load operation and that under normal operation, and one of the results of this examination was that coarse sl was dispersed and precipitated in the Al3r+ mass-based alloy. A bearing has been proposed in Japanese Patent Application Laid-Open No. 58-64336.

This bearing has a cutting force made of hard 3i precipitates, and because it has the cutting force, the uneven surface of the mating shaft is scraped and flattened, improving the bearing performance. To explain the history in detail, on the surface of the mating shaft made of graphite cast iron on which spherical or flaky graphite has been precipitated, during polishing, (5) four parts remain after the fallen graphite particles, and around these recesses there are hard and hard particles. Work-hardened firmness and edge-like protrusions are formed. Therefore, as mentioned above, AlSn-based, An-3n-Pb
In the bearing base metal of a system, etc., abnormal wear is likely to occur during high load operation due to these uneven parts. On the other hand, in the case of the bearing base metal in which the coarse Sl is dispersed and precipitated, the cutting force is applied by the hard Sl precipitates, so the uneven parts of the mating shaft are mechanically cut and flattened. Therefore, abnormal wear and seizure will not occur.

However, if the mating shaft is made of a material other than graphite cast iron, the surface of the mating shaft will be irregularly scratched by coarse S precipitates during high-load operation, resulting in seizure and serious trouble.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks, and specifically,
In Al1-Sn-Pb bearing alloys, the content of Sn and Pb is increased to improve lubricity, and elements such as Cr, 3b, Mn%N1 are added to strengthen the Al matrix, and these ( 6) Elements increase the hardness of the /l matrix, but
On the contrary, these measures actually make the AJ alloy brittle, and during high-load operation, it must be kept at high temperatures (100 to 250"C).
) will not exhibit fatigue resistance. In the present invention, this problem is solved by precipitating 3i particles in an elliptical, spherical, or rounded tip shape in the Al matrix, and in this way, the fire resistance (=j property, Improves wear resistance.

Means for solving the problem and its operation The bearing base metal according to the present invention has a weight percentage of 3 to 35%.
%311.0.1-11% st, o, 1-10% Pb,
One or more of Cu, MCI or Zn alone or in a combined amount of 0.1% to 2%, R, Ml), F
e, x: , (, o, MOlsb, one or more of v or zr in a content or total amount of 0.1
~1%, 0.01-0.3%3r, remainder substantially Al
It is characterized by the fact that 3i particles having a spherical, elliptical, or rounded tip are dispersed and precipitated in the Al matrix.

A more detailed explanation of the configuration of these means and their operation will be as follows.

First, the present invention was accomplished in order to improve fatigue resistance in a highly crystalline state.

That is, in the conventional example, C, which is simply a high melting point element,
Adding roCo, Ni, etc. increases the high temperature strength and prevents the hardness from rapidly decreasing at high temperatures.
-C increases wear 1i. However, in this way, A l
In order to increase the fatigue resistance of -S n -P b alloys under high temperature conditions, it cannot be achieved by simply adding high melting point elements to increase the hardness; instead, the alloy becomes brittle. and the tensile strength, elongation and impact value decrease.

Regarding this point, in the present invention, in order to provide a bearing base metal suitable for the severe strip f1 under high temperature and high load, -C is added as an essential component of 3r, and this 3r is made to act on Si at the time of casting. The S1 crystal particles are spheroidized or a part of the S1 crystal particles are spheroidized, that is, the tips of the S1 crystal particles are rounded, and the Si crystal particles are further spheroidized or rounded by heat treatment under normal conditions. This increases the Al-S
Increases the tensile strength, elongation and impact strength of n-Pb alloys.

In other words, generally speaking, fatigue strength is determined by the tensile strength, elongation, impact strength, and structural structure of the material, and cannot be solved by adding bearing components to the instep. However, in the present invention, Sr is used to make the Si crystal particles spheroidal during casting, and 3r is used to further enhance this spheroidization during heat treatment.

In addition, in the present invention, since deterioration of mechanical properties can be prevented by addition of 3r, even if high melting point elements such as those mentioned above are added to the Δl-3nPb alloy as additive elements,
No sudden deterioration of mechanical properties at high temperatures.

These features of the present invention can be supported by the fact that an improvement in fatigue strength was observed as a result of fatigue tests conducted at high temperatures and under high loads.

Next, by precipitating Si particles with spherical or rounded tips in the Al matrix as described above, a bearing surface that is suitable for high crystallinity and high load conditions and has significantly improved surface performance can be obtained. It will be done.

In general, it is said that it is difficult to understand the phenomenon of f-size in a meaningful way because it reaches this level. However, in a bearing made of a Cu-Pb alloy having a surface layer formed by over-replating F'b-3n alloy on its surface, the surface layer of this plating wears away under high load operation, leading to burnout. On the other hand, it is made of Al-3n-Pb alloy containing SCU,
A bearing that does not have a surface layer formed by overlay plating on its surface will not suffer from burnout.

The inventors of the present invention focused on this point and conducted a comparative structural inspection of both bearings. In other words, FIG. 3 is an enlarged sectional view of a part of a bearing having a surface layer formed by overlay plating on the surface.
Fig. 4 is an enlarged cross-sectional view of a part of a bearing made of an Al3n-Pb gold alloy, which has no overlay metal surface on its surface, and which includes St, (:u, etc.).As is clear from Fig. 3, , this bearing has surface overlay plating @4, alloy layer 5
This overlay is made up of a back metal 6 as well as a backing metal 6.
The axial load is supported by the entire surface of 4. On the other hand,
As shown in Fig. 4, Al-Sn-Pb alloy rs+, C
The bearing containing u, etc. consists of an alloy layer 5 and a back metal 6, and rod-shaped or flaky 3i particles 2 are contained in the matrix of this alloy@5.
is precipitated. Therefore, in this bearing, the load of the mating shaft is supported by the hard Si particles 2, and the Si particles have the cutting force as described above.

In short, the difference between the two is surface contact and point contact, and this difference makes a decisive difference in lubrication and temperature rise of the friction surface. In other words, in surface contact, the temperature of the friction surface rises rapidly under high speed and high load conditions, as shown in the bearing shown in Figure 3, whereas in point contact, as in the bearing shown in Figure 4, the temperature of the friction surface increases rapidly. (11) A gap is formed between the surface of the gold layer 5 and the surface of the mating shaft, and since the oil film in this gap is not subjected to a very large load,
Sufficient lubrication is maintained and temperature rise on friction surfaces is suppressed.

Proceeding further, the present inventors took the basic viewpoint that supporting the shaft load through point contact as shown in Fig. 4 is extremely effective for lubrication under high loads, and found that it is necessary to make the most of its effect. Through research on the composition and structure of the bearing base metal according to the present invention, they completed research on the composition and structure of the bearing base metal.

Specifically, the present inventors focused on the precipitation form of Sl in the bearing base metal, which is an Al-SnPb alloy and contains Sl, Cu, etc., and conducted research on the effect of this form on the lubricating surface. Firstly, Sl is a stable substance with a high melting point and has strong non-metallic properties, and it has a high temperature of 200°C to 500°C to Fe, the main component of the mating shaft.
It has been found that Sl is extremely suitable as a point support means for the axial load (12) because it does not cause any diffusion or dissolution even when it comes into contact with the material at temperatures as high as 10°C.

Second, when supporting a mating material at a point via an oil film, Si particles are so hard that their hardness reaches 599, and since they are not compounds, they are not brittle, have high elasticity, and have a sharp hardness. It was found that it can withstand more fluctuations in direction.

However, despite having the above-mentioned properties, Sl has strong crystallinity and exhibits a plate-like or rod-like shape even in the form of eutectic precipitation with AI, and even after subsequent rolling and heat treatment,
Its shape changes only slightly. For this reason, Si
If the precipitated ml state of particles is not controlled from the time of casting, as shown in Fig.
-The Si particles 2 precipitated together with the Pb alloy particles become plate-shaped or rod-shaped, while they are separated from these S particles 2 by 5n-
Pb alloy particles 3 will be present. In this state, the edges of the hard S particles 2 cannot scrape the mating shaft and are likely to stick together, and on the contrary, the lubricity decreases and seizure occurs.

(13) From this point of view, in the present invention, in order to dramatically improve the -C lubricity, the cutting force is removed from the Si particles, and the edges are controlled to have a rounded shape, such as spheroidization.

That is, FIG. 1 is an enlarged sectional view of a part of a bearing base metal according to one embodiment of the present invention, and as shown in FIG. The Si particles 2 are spherical, and the spherical 3i particles 2 bring the contact closer to the ideal point contact, making it possible to further improve lubricity and wear resistance. In addition, even if a sudden high load is applied at high speed, the mating shaft will not be damaged.
Since 3i is spherical, there is no notch effect in the 71 helix, a matrix with stable strength can be obtained, and it has excellent wear resistance.

This spheroidization of Si particles can be achieved by adding Sr to improve the properties of the A1 alloy liquid phase at the eutectic point where Si precipitates, and furthermore, in the subsequent heat treatment, the conditions are normal conditions (14 ) However, spheroidization is enhanced by 3r.

Furthermore, the addition of Sr changes the precipitation form of the 3n-Pb alloy particles 3, and as shown in FIG.
The 3n-Pb alloy 3 is present more closely adjacent to the 3n-Pb alloy 3. This structure dramatically improves the lubrication performance compared to the conventional structure (see, for example, FIG. 5).

In addition to solving the surface performance structurally as described above,
8L is highly sensitive to heat, and if the temperature exceeds 150'C, it will soften to below 1-IVlog and lose its strength, so it is necessary to strengthen the matrix at high temperatures.
From this point, CLI, MQ, Zn, Cr, Mn, F
e, NCo, Mo, Sb, V, and Zr are added.

That is, among these additive elements, CLI, MCI,
Zn forms a solid solution with 7B and hardens the Al matrix.

When these are in the range of 0.1 to 2%, a part of them dissolves in solid solution and the rest precipitates, and the balance strengthens the Al matrix. ) are added in a single or combined amount of 0.1 to 2%.

Also, Cr, fvln, Fe, Co, Nl, MOlsb
, v, and zr are precipitation-hardening type 71~Rix strengthening elements, and when improving the strength at high temperatures with these strengthening elements, Cr, Mn, Fc, Ni, co, MO5S
The total amount of one or more of b, V, and ZI- is 0.
Add 1 to 1%.

Furthermore, in addition to adding the precipitation hardening type strengthening element in this way, one or two of CLJ, MQ, or Zn is added.
Addition of 0.1 to 2% of these elements alone or in bulk improves strength by solid solution of these elements.

As described above, in the present invention, in addition to simply adding base-strengthening elements as in the past, 3R is added together with these reinforcing elements to improve not only the hardness but also the tensile strength compared to the past. The purpose is to increase fatigue resistance and improve bearing performance under high load operation.The mechanism and composition of each component are as follows.

In the bearing with the configuration shown in Fig. 1, the lubricating surface that supports the shaft load is the tip of the 3i particles 2 protruding from the surface of the 7trix 1, and an oil film is present between the Si particles and the mating shaft. and fluid lubrication is maintained. However, this oil film ruptures when subjected to rapidly fluctuating loads, reaching local boundary lubrication.
At this time, if a 3n-Pb gold alloy film is interposed on the upper surface of the Si particles 2, seizure can be prevented, and the oil film can be normally regenerated to quickly return to a state of fluid lubrication. At this time as well, with the structure shown in FIG. 1, 3n-Pb gold-containing particles 3 exist near the Si particles 2,
Even in the molten state, this alloy has an affinity for lubricated surfaces, making it less likely to run out of oil. In addition, even if the Si particles reach a high temperature due to H friction between the mating shaft and the Si particles, the heat is absorbed by the heat of fusion of 31-Pb, making it difficult to seize the mating shaft with the Al alloy in the nearby matrix. Become. Also, at this time, as shown in FIG. 2, 5n-Pb (
17) At least a portion of the alloy particles 3 is in a liquid phase, and this liquid phase 3a is supplied to the protruding surfaces of the 3i particles 2. This supply amount increases as the temperature rises, and since a liquid phase 3a of 3n-pb is always present on the warm surface of the Si particles 2,
Overheating can be prevented. In short, Si
The structure in which the particles 2 are spherical and the 3n-Pb base metal particles 3 are adjacent to them is very effective in boundary lubrication conditions (oil film has broken), and even in normal fluid lubrication conditions, the hard Si particles 2 It fits properly to the other axis, and it is soft 3 n
- It is covered with a P b layer, which acts as a shock absorber.
perform a certain function.

The reasons for limiting each element as described above are as follows.

First of all, among the elements that form a strong Al matrix, the range of CLl, MQ, /1] etc. is set at 0.1 to 2% because if the addition exceeds 2%, the amount of precipitation increases. ,
This is because it becomes brittle.

Cr, Mn, Fe, Go, N i , MQ2 (1
8) The addition amount of s, b, v, zr is set to 0.1 to 1% because
Within this range, fatigue resistance can be imparted to the bearing, but 1
This is because if the addition exceeds %, the compound will become coarse and its toughness will deteriorate on the contrary.

Furthermore, an appropriate lubricating surface can be formed with Sn in the range of 3 to 35% and Pb in the range of 0.1 to 10%. In addition, Sl has seizure resistance,
It is effective in improving wear resistance, and adding up to 0.1 to 11% can sufficiently maintain this lubricating structure.

In addition, 3r controls the shape of Sl to be spherical, and furthermore, 5n-
It causes Pb particles to precipitate near the S1 particles, and is an extremely effective element. However, if the 5rtf content is less than 0.01%, there is no such effect of addition, and if the content exceeds 0.3%, cavities are more likely to occur during casting, thereby causing problems.

Example Next, embodiments of the present invention will be described.

Example 1 First, an Al-Sn bearing (19) alloy having the composition shown in Fig. 1 was milled on the upper and lower surfaces to a thickness of i, Q mm by continuous casting, and then cold rolled to a thickness of 2 mm. Pressed down. In this state, a heat treatment was performed at 300 to 350° C. to remove strain, and the bearing was then crimped to a back metal iron plate through a thin plate of pure Δl to obtain a bearing with a thickness of 1.50 i+m.

The C test material islands 1 to 5 on the back side of these bearings are conventional test materials that do not contain Sr, and Na 6 to 42 are samples according to the embodiments of the present invention, with 13% Sn and 2.0%. Pb, 3.0%
In addition to Si, 0.03% 3r, C0, MO571], C
Small amounts of r, Mn, Fe, C01Ni, Mo, and Sb are added.

Each of these test materials was used as a bearing at room temperature and 20°C.
In order to examine the mechanical properties at 0°C, bow tensile strength, elongation and hardness tests were conducted and are shown in Table 2. In addition,
Each sample material was made of Al-Sn by removing the backing metal by machining.
Only the alloy part is used, and the shape of the test piece is JIS z 2.
201 No. 5.

(20) From these results, test materials IIO, 6 to 42 have higher strength at high temperatures (200 °C) than conventional materials, and Cu2M
g, Zn and Cr%Mn, Fe, Co.

The effects of adding Ni, Mo, Sb, V, and 7r can be seen.

In other words, it is thought that the spheroidization of Sl and the reinforcement of the matrix were phased out, resulting in improved hardness and strength. It can be said that the overall mechanical properties at high temperatures have improved.

Next, in order to find out the seizure resistance and abrasion resistance of the sample materials, a test was conducted using a precious wood type friction and wear tester, and the test conditions were as follows.

Masatsu speed 4 m,,'Sec partner material 545CS &! jAsaHRC=
55 side roughness 0.8~1.08 SAE, 20w-40 150±5°C 100klJ, 10kg from "CI", ・'oF3te
The blood pressure is increased for 15 minutes until seizure occurs at p, and the blood pressure that causes seizure is taken as the seizure load (21).

Abrasion resistance On the other hand, to check the abrasion resistance, 100 klL'
The test was carried out at a constant Cl2 for 6 hours, and the weight change thereafter was observed.

The results are shown in Table 2.

According to this, all of test materials 6 to 42 exhibit better burn resistance and wear resistance than conventional materials, and it can be seen that the addition of Sr and matrix reinforcing elements also improves surface performance. . This indicates that the alloy according to the present invention has an excellent lubrication mechanism.

Next, each sample material was actually processed into a semi-cylindrical bearing product shape, and a final bearing fatigue test was conducted, and the results shown in Table 2 were obtained. This is a test in which the bearing is fixed to the rod and an eccentric load is applied to the shaft, similar to the conditions of an actual engine, and the durability test is evaluated based on the length of time the bearing is maintained under the following conditions.

Surface pressure 600 kQ f,・i(22
) Number of revolutions 4 00Cr, p, m by partner month
FC1 70, Ara 1 no 0, 8 = 1.58 Oil used SAF 20w-40n 111nh Crystal'150°C ± 5'C d5, Upper limit of this test time t; 1300 hours and 11
, N...5 are shown in Table 2. As a result, both a5 and A5 showed better durability compared to the conventional materials used as comparative examples.
The alloy according to the invention exhibits excellent 114 fatigue properties.

However, when 0.03% of 3r was added to the alloy of conventional example L+, 2 (S in sample No. 61), the changes in the morphology of S (in sample No. 61) were as shown in Figures 6 and 7. .

In addition to Figure 6, Figure 7 shows the microscopic structures of the conventional alloy and the alloy according to the present invention. It was deeply etched so that it could be seen, and it was imaged using an electron microscope to create a schematic diagram. As can be clearly seen from this true schematic diagram, the bearing base metal according to the present invention has a spherical shape due to the addition of 5rI7). In order to confirm whether or not there is an effect of improving the brittleness of the steel, the impact value was measured as a substitute property, and the improvement effect of the addition of 3r was determined through experiments.

As sample materials for the experiment, a comparative experiment was conducted using No. 5, which is a conventional material not containing 3r, shown in Table 1 of Example 1, and No. 6, which is a material according to the present invention.

The experiment was conducted using No. 3 test hat n = 51 according to JIS z 2242, Shirelby Naka I impact test method.

As a result of the experiment, the average value of the conventional material was 0.84 ku-m, but the average value of the material according to the present invention was 2.78 k[J・1η
. . . It was clearly observed that the bearing base metal according to the present invention had an improvement effect due to the addition of 3r.

, Effects of the Invention> As explained in detail above, the present invention has an effect of 3 to 3% by weight.
5% Sn, 0.1 to 11% Si is 1. m(27) containing 0.1 to 10% Pb, containing 0.1 to 2% of one or more of Cu, MCI, or Zn alone or in total; Cr, Mn, Fe, Co
, N i , Mo, Sb, V or 7r, at least one or two or more of them alone or in a combined amount of 0.1 to
Al-3n containing 1%, with the remainder consisting essentially of Al.
Add 0.01 to 0.3% of 3R to the J5 bearing alloy, and precipitate Si particles in the matrix into a spherical, elliptical, or rounded tip shape. It is made up of IC.

The bearing alloy of the present invention with this configuration has extremely excellent lubricity,
In addition, the bearing base metal has extremely good mechanical properties at high temperatures of 100 to 250°C, and can withstand severe operating conditions due to high-load operation.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a part of a bearing base metal according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the lubrication mechanism of the bearing base metal shown in FIG. 1, FIG. 3 and (28) Fig. 4 is an enlarged sectional view of a part of a conventional bearing, Fig. 5 is an enlarged sectional view of a part of the bearing base metal of Fig. 4, and Fig. 6 shows the structure of the bearing base metal of the conventional example. FIG. 7 is a schematic diagram of a microscopic photograph showing the structure of the bearing base metal according to the present invention. Code 1...71~Rix 2...Si particles 3...3 II-p b alloy particles 3 a-=
-3n -P b 71! 2 phase 4... Overlay plating circle b... Bearing base metal gap 6... Back metal Fig. 1 9S bar - Pb alloy particles

Claims (1)

[Claims] 1) In weight%, 3-35% Sn, 0.1-11% Si,
0.1 to 10% of one or more of Pb, Cu, Mg or Zn, alone or in total, 0.1 to 2%;
One or more of Cr, Mn, Fe, Ni, Co, Mo, Sb, V or Zr in a single or combined amount of 0.1 to 1%, 0.01 to 0.3% Sr, The remainder essentially consists of Al, and Si particles having a spherical, oval, or rounded tip are dispersed in the Al matrix.
An Al-Sn-Pb bearing alloy characterized by being precipitated.