JPS6031894B2 - High strength aluminum alloy for bearings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum alloy for bearings that is strong and has excellent heat resistance.

In recent years, as aluminum alloys have expanded into various industries,
Its use as a material for bearings is also becoming more popular.

However, the strength of the aluminum alloys for bearings, which are mainly made of Al-Sn, which have been used in the past, is lower than that of copper alloy materials such as high-strength yellow steel and phosphor bronze, which are also used as bearing materials. For example, when used as a bearing material for load bearings such as sliding bearings for internal combustion engines such as ships and wheels, there are problems with using aluminum alloy materials alone, and they are often used as a mating material with steel as the backing metal.
However, products using this laminated material are not only extremely troublesome to manufacture due to technical difficulties in joining aluminum and steel, but are also disadvantageous in terms of cost.

On the other hand, A-Zn-Mg alloys among aluminum alloys are known as relatively high-strength aluminum alloys, and are sometimes used as solid-type bearing materials.
It has poor high-temperature properties and wear resistance, but its performance as a bearing material is lacking. However, the inventors of the present invention
Focusing on the bearing characteristics and strength characteristics of the Zn-Mg alloy,
The present invention was completed as a result of intensive research into providing a strong solid type aluminum alloy bearing material by adding heat resistance, wear resistance, and bearing properties to this material. Zn3-10
%, Mg0.6-1.5%, Sil-4%, Mno. 4
~1.0% and Cuo. 2 to 0.6% as an essential component, and further contains Pbo. 5-3%, Sno. 5-3%
, Cro. 05-0.3%, Zro. 05-0.25%
, Tio. 2% or less and BO. 1 of 05% or less
This is a high-strength aluminum alloy for bearings, which contains one or more selected components, with the remainder consisting of aluminum and impurities.

The alloy of the present invention has strength almost comparable to yellow steel, good wear resistance, and also has excellent heat resistance, so it can be said to be suitable as a bearing material.

Next, the reason for adding the alloy component elements to the alloy of the present invention will be described. [1} Zn3-10% Zn gives bearing properties and strength to the alloy, and 3
If it is less than 10%, the effect of increasing bearing characteristics and strength will be small;
Above this, the alloy becomes susceptible to stress corrosion.

(2) Mg0.6-1.5% MS is effective in increasing alloy strength by aging treatment by coexisting with Zn and Si.

If it is less than 0.6%, the strengthening effect due to aging is insufficient;
If it exceeds 1.5%, processability will be significantly impaired.

{3} Sil~4% Si is finely and uniformly dispersed as a eutectic in the alloy matrix, and has the effect of improving the alloy strength and wear resistance, and some of it combines with Mg and is absorbed by aging treatment. It increases strength.

If it is less than 1%, the effect will be small, and if it is more than 4%, workability will decrease.

[4) Mno. 4 to 1.0% Mn has the property of spheroidizing the acicular A-Fe-Si compound formed by Fe present as an impurity in the alloy, thereby imparting strong ballability to the alloy, and also making it spheroidized by heat treatment. The resulting fine precipitates impart heat resistance to the material.

However, if it is less than 0.4%, the above effect will not be fully exhibited, and if it is more than 1%, coarse Mn crystals will be produced during coin coin minting, which is not preferable in terms of material production. [5- Cuo.
2 to 0.6% Cu has the effect of solidifying into the aluminum substrate to increase strength and wear resistance.

If it is less than 0.2%, the effect will be small, while if it is more than 0.6%, corrosion resistance will deteriorate.

The above describes the reasons for adding alloying elements that are added as essential alloy components in the alloy of the present invention, but in the present invention, depending on the purpose of bearing use,
6) By supplementarily adding one or more of the selected alloy components whose reasons for addition are shown below, the performance as a bearing material can be more effectively exhibited.

■Pbo. 5 to 3% Pb is distributed as a single substance along grain boundaries without forming a solid solution in aluminum, and has the effect of imparting drizzle resistance to the alloy and dust embeddability.

However, if it is less than 0.5%, there is no effect, and if it is more than 3%, the alloy becomes brittle and the workability is reduced. '7'Sno
．． 5-3% Sn hardly forms a solid solution in the aluminum matrix and is distributed alone in the form of a network or small particles, and improves the fatigue resistance of the alloy. If it is less than 0.5%, the effect is poor, Moreover, if it exceeds 3%, the alloy becomes brittle and workability decreases.

■ Cro. 05-0.3% Zro. 05 to 0.25% Cr and Zr have the effect of preventing recrystallization of the aluminum alloy, and therefore have the effect of preventing the strength of the material from decreasing at high temperatures.

If both Cr and Zr are less than 0.05%, their effects are insufficient, and even if they are added above their respective upper limits, no further effects can be expected, and in addition, large crystals of these elements often form during casting. crystallizes and causes material defects. ■ Tjo. 2% or less BO. 0.5% or less Ti and B refine the aluminum casting structure, improve room temperature strength, and are also effective in improving workability.

Below each lower limit value, the effect is small, and above the upper limit value, the strength decreases, which is not preferable. When obtaining a bearing material using the alloy of the present invention, the twill is finished into an arbitrary shape by general processing methods such as extrusion and forging, and this is
150-2 after undergoing melting treatment at a temperature of 0-530℃
By performing artificial aging treatment at a temperature of 0,000° C. for several hours to 1 European hour, it is possible to impart excellent strength as a bearing village.

Next, the present invention will be explained based on examples.

Table 1 shows the chemical structure of the alloy used in this example. Run numbers 1 to 5 show the chemical compositions of the alloys of the present invention, and run numbers 6 and 7 show the chemical compositions of conventional alloys used for comparison.

Table 1 and Table 2 show the alloys shown in Table 1 with 98 ribs? After semi-continuous casting into pillars, the Zenitama was soaked at 530°C for 8 hours, then extruded to form an extruded material with a cross section of 35 ribs x 14 sides, and then the extruded material was subjected to general treatment at 530°C for 1 hour. This figure shows the results of measuring the mechanical properties at room temperature of samples that were water-quenched and then subjected to artificial aging treatment at 170 oo for 10 hours.

Table 2 From Table 2, the present invention alloys (execution numbers 1 to 5) are different from the conventional alloys (
Both the tensile strength and proof elongation values at room temperature were higher than those of Example Nos. 6 and 7), which indicates that the alloy has excellent toughness and is suitable as a high-load solid bearing material.

Furthermore, Table 3 shows the results of the present invention alloys (execution numbers 2 and 4) and the conventional alloy (execution number 6) among the same samples at room temperature and 1
These are the results of measuring tensile strength at each temperature of 50qo, 200qo, and 250qo. Table 3 Table 3 shows that the alloy of the present invention has a higher tensile strength at high temperatures than conventional alloys, and this indicates that the alloy of the present invention can sufficiently withstand a certain amount of heat generated in the bearing part due to high-speed, high-load operation. It turns out that.

Table 4 shows the results of the abrasion resistance test of the samples using a Timken testing machine with a steel ring and test piece wire contact type.

The test conditions were a steel ring (load: 4.54k9) placed on the test piece, and a rotational speed of 80°. p. m. (Peripheral speed 2.07m/min
) for 10 minutes, and the area of the wear marks produced on the test piece at that time was measured. Table 4 It can be seen from Table 4 that the alloys of the present invention (Example Nos. 1 and 2) have a smaller wear scar area and are also better in wear resistance than the conventional gold (Example Nos. 6 and 7).

Comparing the various test results mentioned above, the alloy of the present invention has much higher strength than conventional alloys at both room temperature and high temperature, and has excellent wear resistance, so it is particularly suitable for aluminum alloy bearings. It can be said that it is suitable as a solid type bearing material.

Claims (1)

[Claims] 1 Zn3~10%, Mg0.6~1.5%, Si1~
4%, Mn0.4-1.0%, Cu0.2-0.6%,
Contains Pb0.5-3%, S as an essential component.
n0.5~3%, Cr0.05~0.3%, Zr0.0
A high-strength aluminum alloy for bearings, which contains one or more of the following as selective components: 5% to 0.25%, Ti: 0.2% or less, and B: 0.05% or less, with the balance being Al and impurities.