JPH0536486B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a copper-based sliding alloy that has excellent non-seizure properties, wear resistance, and corrosion resistance, and more specifically, equipment materials used under severe sliding conditions.
For example, the present invention relates to a sliding copper-based alloy suitable as a material for a floating bearing (floating bush bearing) of a turbocharger. Problems to be Solved by the Prior Art and the Invention In general, materials for floating bush bearings for turbochargers include free-cutting brass alloys (JISH3250), lead bronze alloys (JISH5115),
There are Japanese Patent Publications No. 44135/1983 and Japanese Patent Publication No. 11735/1987 regarding low friction, high strength brass alloys as earlier patented inventions by the present applicant. Regarding the alloy, the corrosion resistance against deteriorated oil, anti-seizure property under high temperature and boundary lubrication conditions, and wear resistance were not fully satisfactory. Furthermore, since the matrix of the alloy is a mixed structure of α+β phase or a single structure of β phase, it is not possible to contain a large amount of Pb due to metallurgy, and the anti-seizure properties are poor. In recent years, the use of turbochargers in engines has progressed rapidly, and the floating bush bearings used in the bearings of turbochargers installed in internal combustion engines (engines) are subject to various factors such as ambient temperature, oil supply amount, and degree of oil deterioration. Operating conditions are becoming increasingly severe. As the bearing temperature rises to around 400℃ due to heat conduction from the turbine, the sulfur in the lubricating oil combines with the copper in the bearing metal due to the properties of the oil and the temperature, resulting in copper sulfide (copper sulfide). CuS) is produced on the surface of the bearing metal, and a blackide layer containing copper sulfide as the main component is formed on the surface of the bearing metal (referred to as blackening corrosion phenomenon). This has become a major problem as it grows over time and causes wear and tear during use, eventually making it impossible to maintain its function as a floating bush bearing. Furthermore, the anti-seizure properties after stopping lubrication during dry-up at temperatures exceeding 300°C are not fully satisfactory, which has become a major problem. Note that dry-up refers to a state in which the lubricating action of lubricating oil at high temperatures has stopped. More specifically, a turbocharger uses the high-temperature, high-pressure gas energy contained in the exhaust gas to rotate a turbine blade, which in turn rotates a compressor coaxial with the turbine blade.It operates while the engine is running. Therefore, for example, when the engine stops immediately after high-speed operation, the lubricating oil pressure disappears and oil cooling cannot be expected. Thermal energy stored in the high-temperature turbine housing flows into the low-temperature side by thermal conduction, raising the temperature of the bearing section. The aforementioned problems are problems associated with this phenomenon. In general, lead-bronze alloys containing copper, lead, and tin as the main components and free-cutting brass alloys containing copper, zinc, and lead as the main components are generally used as materials for floating bush bearings in turbochargers. There is. However, in lead bronze bearings, during dry-up when the temperature reaches 300°C, the sulfur content in the lubricating oil reacts with the copper, accelerating the formation of a blackide layer, and further causing rapid surface wear. On the other hand, although free-cutting brass alloys have excellent corrosion resistance, they have poor affinity with lubricating oil after lubrication has stopped, and therefore seizure or galling may occur relatively early. The present invention was devised against this technical background, and has sufficient wear resistance and excellent non-seizure properties even under severe usage conditions such as high speed, high temperature, and highly corrosive environments, as typified by turbochargers. The object of the present invention is to provide a new copper-based sliding alloy as a high-performance wear-resistant material that has high corrosion resistance and excellent corrosion resistance. Means for Solving the Problems This object is achieved by providing the following copper-based sliding alloys having excellent non-seizure properties, wear resistance and corrosion resistance. Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, the remainder: Cu and unavoidable impurities (all figures are weight%), and the Pb is uniformly dispersed throughout the entire structure, and the matrix A copper-based alloy consisting of a single α-phase structure. Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.02
At least one of the two components of ~1.5% Mg and 0.1 to 1.5% Te, the remainder: Cu and unavoidable impurities (all numbers are weight %),
A copper-based alloy in which the above-mentioned Pb is uniformly dispersed throughout the structure and the matrix consists of a single α-phase structure. Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.5~
At least one of two components: 3.0% Ni and 0.3 to 3.0% Al, the remainder: Cu and unavoidable impurities (all numbers are weight %), and the Pb is uniformly dispersed throughout the entire structure. , a copper-based alloy whose matrix consists of a single α-phase structure. Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.02
At least one of the two components ~1.5% Mg and 0.1~1.5% Te, 0.5~3.0% Ni and 0.3~3.0%
% of Al, the remainder: Cu and unavoidable impurities (all numbers are weight %), the Pb is uniformly dispersed throughout the entire structure, and the matrix is a single α phase. A copper-based alloy consisting of a structure. The reasons for adding and limiting the content of each alloy component in the copper-based alloy are as follows. (1) Zn: 10 to 23% by weight Zn has the effect of imparting strength, wear resistance, and corrosion resistance to lubricating oil. The amount added varies depending on the zinc equivalent and amount added of other additive components, but if it is less than 10%, the above effect will be small, and in particular, Zn Amount of 10% or more is required. Furthermore, when α+β phase is generated,
Since the amount of lead added to impart anti-seizure properties to the alloy is suppressed, Zn It is desirable that the maximum amount of addition is 23%. (2) Mn: 1.0 to 3.0% by weight Mn forms an intermetallic compound Mn ₅ Si ₃ with excellent sliding properties with Si, contributing to improved wear resistance and seizure resistance, and also improves intermetallic contact. Prevents the flow of the substrate when it occurs. If the Mn content is less than 1.0%, the effect will be small;
%, the effect is almost saturated. Furthermore, if the Mn content exceeds 3.5%, the alloy will become embrittled, so in order to reliably prevent this embrittlement phenomenon, it is desirable to set the upper limit of the Mn content to 3.0%. (3) Si: 0.3 to 1.5% by weight As mentioned above, Si forms a compound called Mn ₅ Si ₃ with Mn, and contributes to improving wear resistance and seizure resistance. Its content is determined by the composition ratio of the Mn ₅ Si ₃ compound, and when the weight ratio of Mn to Si is 1:0.3, all Si becomes a compound. Therefore, Si needs to be at least 0.3% by weight, and if it exceeds the upper limit of 1.5%, too much free Si will crystallize, leading to embrittlement of the alloy. (4) Pb: 5-18% by weight Pb has self-lubricating properties and melts due to frictional heat, flows onto the sliding surface and forms a thin film of several microns, resulting in excellent anti-seizure properties. It also improves machinability. In order to form such a film of several microns, the composition of Pb in the alloy must be at least 5
% or more is required. However, as the strength of the alloy decreases as Pb increases, the upper limit is set at 18%. For the above reasons, the amount of Pb added is 5~
18% by weight. (5) Mg: 0.02 to 1.5% by weight Mg is effective in uniformly dispersing Pb and is also effective in improving the strength of the matrix. If the amount added is less than 0.02%, the above effect will be small, and if it is too much, the intermetallic compound of Mg and Pb will crystallize too much, and the self-lubricating effect of Pb will be impaired.
For the above reasons, the amount of Mg added is 0.02 to 1.5% by weight. (6) Te: 0.1 to 1.5% by weight Te is effective in improving the uniform dispersion of Pb, non-seizure properties, and toughness when added in small amounts, as well as improving corrosion resistance. However, if it is less than 0.1% by weight, the effect cannot be expected;
Adding a larger amount increases the cost and does not particularly improve the effect, resulting in fewer benefits.
Therefore, the amount of Te added is 0.1 to 1.5% by weight. (7) Ni: 0.5-3.0% by weight Ni strengthens the matrix, improves strength and wear resistance. Furthermore, Ni increases the recrystallization temperature and has the effect of preventing crystal grain coarsening during hot plastic working. However, if it is less than 0.5% by weight, the above effect will not be observed, and if it exceeds 3%, fatigue strength and impact resistance will be significantly reduced. Therefore, the amount added is 0.5 to 3.0% by weight. (8) Al: 0.3 to 3.0% by weight Al is effective in strengthening the matrix. If the amount added is less than 0.3% by weight, no effect on strength can be expected, and if it is more than 3.0% by weight,
This causes problems such as embrittlement and coarsening of crystal grains. Therefore, the amount added is 0.3 to 3.0% by weight. Test Example 1 (Alloy of the present invention) After casting alloys having the compositions No. 1 to No. 9 shown in Table 1 by a continuous casting method, extrusion processing and drawing processing were performed to create a rod-shaped body with a diameter of 35 mm. Next, the rod-shaped body was processed to obtain samples for seizure tests, wear tests, and corrosion tests. Various test conditions for the sample are shown in Tables 2 to 4, seizure test results are shown in Table 5, wear test results are shown in Table 6, and typical corrosion test results are shown in Table 8. . Test Example 2 (Conventional Alloy) After casting alloys with compositions No. 10 to No. 13 shown in Table 1 by continuous casting, extrusion processing and drawing processing were performed to create a rod-shaped body with a diameter of 35 mm. A test sample similar to Test Example 1 was obtained by processing a rod-shaped body. Various test conditions for the samples are shown in Tables 2 to 4, and test results are shown in Tables 5 to 8, respectively. Although each test example was conducted on samples made by continuous casting, similar effects can also be obtained by methods such as pour-in-place casting, and there are no particular limitations on the casting method. isn't it.

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[Table] [Evaluation of test results] Comparing the seizure test results in Table 5, we can see that the conventional alloy free-cutting brass type (No. 10), high-strength brass type (No. 12,
13), all of the products of the present invention have a maximum load of
It can be seen that seizure does not occur even at 500Kgf/cm ² . Incorporate the sample into the actual machine as shown in Table 7,
Even in a seizure test conducted at a constant rotation speed with oil turned on and off, no seizure was observed with the product of the present invention. It is clear that the product of the present invention exhibits extremely excellent performance as a sliding material and can achieve sufficiently satisfactory results as a metal for floating bush bearings. A comparison of the wear test results shown in Table 6 shows that the products of the present invention all have a smaller amount of wear than the conventional products, and it is clear that they have excellent wear resistance. The bushing wear test was conducted using a wet method using lubricating oil, and a hardened S55C for general shaft material was used as the friction partner member. Regarding typical corrosion tests of the products of the present invention and conventional products, as shown in Table 8, the products of the present invention showed better results. Effects of the Invention The copper-based alloy of the present invention has superior seizure resistance, as well as excellent wear resistance, corrosion resistance, and conformability, compared to conventional alloys. In particular, it has excellent performance as a sliding material for turbochargers, etc., which require high performance and long life.

Claims (1)

[Claims] 1. The chemical composition is Mn: 1.0 to 3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, balance:
Non-seizure properties, characterized in that the Pb is Cu and unavoidable impurities (all numbers are weight %), the Pb is uniformly dispersed throughout the structure, and the matrix is composed of a single α-phase structure; Copper-based alloy for sliding parts with excellent wear and corrosion resistance. 2 Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.02~
At least one of two components: 1.5% Mg and 0.1 to 1.5% Te, the remainder: Cu and unavoidable impurities (all numbers are weight %), and the Pb is uniformly dispersed throughout the entire structure. A copper-based alloy for sliding parts, which has excellent anti-seizure properties, wear resistance, and corrosion resistance, and is characterized by a matrix consisting of a single α-phase structure. 3 Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.5~
At least one of the two components of 3.0% Ni and 0.3 to 3.0% Al, the remainder: Cu and unavoidable impurities (all numbers are weight %), and the Pb is uniformly dispersed throughout the entire structure. A copper-based alloy for sliding parts, which has excellent anti-seizure properties, wear resistance, and corrosion resistance, and is characterized by a matrix consisting of a single α-phase structure. 4 Its chemical composition is Mn: 1.0-3.0%, Si: 0.3
~1.5%, Zn: 10~23%, Pb: 5~18%, 0.02~
At least one of two components: 1.5% Mg and 0.1-1.5% Te, 0.5-3.0% Ni and 0.3-3.0% Al
At least one of the two components, the remainder: Cu and unavoidable impurities (all numbers are weight %), the Pb is uniformly dispersed throughout the structure, and the matrix is composed of a single structure of α phase. Copper-based alloy for sliding parts with excellent non-seizure properties, wear resistance and corrosion resistance.