Aluminum bronze alloy and sliding members using the alloy

Abstract

To provide an aluminum bronze alloy excellent in both corrosion resistance (suppression of precipitation of a β-phase) and wear resistance (collateral over a certain level of hardness of metal) and capable of stable manufacturing, and a slide member using the aluminum bronze alloy that has corrosion resistance, wear resistance and stability during manufacture.SOLUTION: An aluminum bronze alloy of the present invention is an aluminum bronze alloy consisting of copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), silicon (Si) and inevitable impurities, and has an α phase, a coarse Fe-Si intermetallic compound of 1 μm or more, a fine κ phase different from the Fe-Si intermetallic compound, and a trace amount of an unavoidable phase.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an aluminum bronze alloy and a sliding member using the alloy.

Background Art

[0002] Practical aluminum bronze alloys are classified into four types, CAC701 to CAC704, in Japanese Industrial Standards (JIS). They are composed of 7 to 10% by weight of aluminum (Al), 0.5 to 4.5% by weight of nickel (Ni), 0.5 to 5% by weight of iron (Fe), 0.1 to 2% by weight of manganese (Mn), and the balance of copper (Cu) and inevitable impurities with respect to the total weight. These aluminum bronze alloys are widely used in industrial applications such as chemical industry parts, ship parts, and machine parts from the viewpoints of chemical and mechanical properties such as corrosion resistance, seawater resistance, and wear resistance. In particular, the aluminum bronze alloy represented by CAC703, which is composed of 8.5 to 10.5% by weight of Al, 3 to 6% by weight of Ni, 3 to 6% by weight of Fe, 0.1 to 1.5% by weight of Mn, and the balance of Cu and inevitable impurities with respect to the total weight, is excellent in corrosion resistance and is used as a bearing for seawater.

[0003] In Patent Document 1, an aluminum bronze alloy excellent in acid and corrosion resistance is disclosed. The aluminum bronze alloy is composed of 3 to 1²% by weight of Al, 4 to *% by weight of Ni, 3 to 6% by weight of Fe, 0.3 to 5.0% by weight of silicon (Si), and the balance of copper (Cu) and inevitable impurities with respect to the total weight. Since the aluminum bronze alloy is excellent in acid and corrosion resistance, it is mainly used as a member of an acid cleaning device.

[0004] In Patent Document 2, an aluminum bronze alloy for a synchronizer ring excellent in wear resistance is disclosed. The aluminum bronze alloy is composed of 7.5 to 9.5% by weight of Al, 7 to 11% by weight of Ni, 7.0 to 9.5% by weight of Fe, 1 to 4% by weight of Si, and the balance of copper (Cu) and inevitable impurities with respect to the total weight. The aluminum bronze alloy is excellent in wear resistance and has a large friction coefficient, so it is suitable as a synchronizer ring member. It should be noted that there are some incorrect or unclear parts in the original text, such as "1²%" and "*%" in the translation of Patent Document 1 content. You may need to check and correct the original text for more accurate translation.

[0005] Furthermore, it is known that adding tin (Sn) to conventional aluminum bronze alloys improves their sliding performance. Because these aluminum bronze alloys have excellent corrosion resistance, they are used in bearing bushings, sliding shoes, worm gears, and shaft bearings for turbochargers. (For example, Patent Document 3) [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 51-47519 [Patent Document 2] European Patent Application Publication No. 1279749 [Patent Document 3] Special Publication No. 2017-515974 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, even conventional aluminum bronze alloys, particularly CAC703 which has excellent corrosion resistance, suffer from reduced resistance to high loads and decreased wear resistance in seawater environments. The aluminum bronze alloy described in Patent Document 1 has issues with wear resistance and is difficult to use as a sliding member. Furthermore, the aluminum bronze alloy described in Patent Document 2 has issues with corrosion resistance and is difficult to use in seawater or chemically active environments.

[0008] To increase resistance to high loads and improve wear resistance, it is conceivable to harden the microstructure of aluminum bronze alloys. Within the microstructure, there is a β phase that is harder than other phases, and generally, depositing this β phase within the microstructure makes aluminum bronze alloys harder. However, an increase in the β phase in aluminum bronze alloys makes them more susceptible to metal corrosion. In water, especially seawater, metal corrosion occurs significantly, and the functionality of the aluminum bronze alloy deteriorates over time.

[0009] Furthermore, while the aluminum bronze alloy with added Sn described in Patent Document 3 improves sliding performance and wear resistance, it has the drawback of being easily damaged during metal processing. In particular, casting defects occur in centrifugal and sand casting of large-diameter components, making stable manufacturing difficult.

[0010] Therefore, from the viewpoint of suppressing the precipitation of the β phase and hardening the microstructure (matrix) of the aluminum bronze alloy, it is necessary to harden a portion of the microstructure by constituting it with a phase other than the β phase. In order to harden a portion of the microstructure, it is necessary to adjust the constituent elements of the aluminum bronze alloy and the respective amounts of each constituent element. Furthermore, from the viewpoint of improving stability during manufacturing, it is necessary to adjust the amounts of Al and / or Ni without adding Sn.

[0011] To solve the above problems, the present invention aims to provide an aluminum bronze alloy that is excellent in both corrosion resistance (suppression of β phase precipitation) and wear resistance (ensuring a certain level of metal hardness), and that can be manufactured stably. Furthermore, the invention aims to provide a sliding member using this aluminum bronze alloy that has corrosion resistance, wear resistance, and stability during manufacturing. [Means for solving the problem]

[0012] (1) The aluminum bronze alloy of the present invention is An aluminum bronze alloy comprising copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), silicon (Si), and unavoidable impurities, For the entire amount, Al content is 9.5% by weight or more and 10.5% by weight or less. Ni is between 6.0% by weight and 8.0% by weight. Fe is between 4.0% by weight and 6.0% by weight. The Si content is 1.0% by weight or more and 2.0% by weight or less. The remainder is Cu and unavoidable impurities. The structure consists of an α phase, a coarse Fe-Si intermetallic compound with a length of 1 μm or more in the short direction, a κ phase separate from the Fe-Si intermetallic compound, a fine κ phase with a length of less than 1 μm in the short direction, and a trace amount of an unavoidable phase. Coarse Fe-Si intermetallic compounds constitute 4% to 14% of the total area ratio in the cross-section of the metal relative to the overall structure. The present invention is characterized by the dispersion of fine, punctate and / or linear κ-phase particles throughout the entire tissue.

[0013] With this aluminum bronze alloy configuration, the precipitation of the β phase is suppressed, thus improving the corrosion resistance of the metal. Furthermore, coarse Fe-Si intermetallic compounds precipitate in the microstructure at a certain rate, and fine κ phases, separate from the Fe-Si intermetallic compounds, are dispersed throughout the microstructure in a point-like and / or linear form, thus ensuring the hardness of the metal. Consequently, when used as a sliding member, resistance to high loads and wear is improved. Moreover, since no Sn is added, manufacturing defects can be reduced, and stable production is possible.

[0014] (2) Furthermore, in the aluminum bronze alloy of the present invention, For the entire amount, Al content is 9.5% by weight or more and 10.5% by weight or less. Ni is greater than 7.0% by weight and 8.0% by weight or less. Fe is between 4.0% by weight and 6.0% by weight. The Si content is 1.0% by weight or more and 2.0% by weight or less. The remainder is preferably Cu and unavoidable impurities.

[0015] With an aluminum bronze alloy having this configuration, the precipitation of the β phase is further suppressed compared to the aluminum bronze alloy described in (1), thus further improving the corrosion resistance of the metal. In addition, the amount of fine κ phase other than the coarse Fe-Si intermetallic compounds in the microstructure is increased compared to the aluminum bronze alloy described in (1), improving the hardness of the microstructure. Therefore, when used as a sliding member, it improves resistance to high loads and wear resistance.

[0016] (3) Further, in the aluminum bronze alloy of the present invention, the Rockwell hardness is preferably 17 or more HRC.

[0017] According to the aluminum bronze alloy having such a configuration, since the Rockwell hardness is 17 or more HRC, it exhibits excellent wear resistance and can maintain the function of the member using the alloy for a long period of time. Further, when used as a sliding member, it improves the resistance to high loads and wear resistance.

[0018] (4) Further, in the aluminum bronze alloy of the present invention, the maximum dealuminization corrosion depth based on the corrosion test method conforming to ISO6509-1981 is preferably 120 μm or less.

[0019] According to the aluminum bronze alloy having such a configuration, since the maximum dealuminization corrosion depth is 120 μm or less, the metal is less likely to corrode, and thus the corrosion resistance is improved. Therefore, for example, even in an environment rich in chemical activity for metals, such as seawater, the function as an aluminum bronze alloy can be maintained for a long period of time.

[0020] (5) The sliding member of the present invention is a sliding member in which the sliding surface is formed of the aluminum bronze alloy according to any one of the above (1) to (4).

[0021] According to the sliding member having such a configuration, since the sliding surface is formed of an aluminum bronze alloy excellent in corrosion resistance and wear resistance, the sliding performance of the sliding member can be maintained for a long period of time.

[0022] (6) Further, in the sliding member of the present invention, it is preferable that a plurality of holes, grooves or recesses are formed in the sliding surface, and a solid lubricant is embedded and fixed in these holes, grooves or recesses.

[0023] With a sliding member having this configuration, a solid lubricant is embedded and fixed in a part of the sliding surface. Therefore, the excellent corrosion resistance and wear resistance of the aluminum bronze alloy, along with the low friction of the solid lubricant, further improve the wear resistance of the sliding member.

[0024] (7) Furthermore, in the sliding member of the present invention, It is preferable that part or all of the sliding member is used in seawater.

[0025] With a sliding member having such a configuration, the sliding surface is formed of an aluminum bronze alloy which has excellent corrosion resistance and wear resistance. Therefore, even if the sliding member is used in seawater, wear and corrosion can be suppressed over a long period of time, and the sliding performance of the sliding member can be maintained. [Brief explanation of the drawing]

[0026] [Figure 1] This is a schematic diagram showing the sliding member of the present invention. [Figure 2] This is an optical microscope image showing the microstructure of an aluminum bronze alloy corresponding to Example 2 of the present invention. [Figure 3] This is an optical microscope image showing the microstructure of an aluminum bronze alloy corresponding to Comparative Example 1, which is different from the examples of the present invention. [Figure 4] This is an optical microscope image showing the microstructure of an aluminum bronze alloy corresponding to Comparative Example 4, which is different from the examples of the present invention. [Figure 5] This figure shows the relationship between the area ratio of the Fe-Si intermetallic compound in the aluminum bronze alloy of the present invention, the amount of bearing wear, and the coefficient of friction. [Figure 6] This figure illustrates the relationship between the Rockwell hardness of the aluminum bronze alloy of the present invention, the amount of bearing wear, and the coefficient of friction. [Modes for carrying out the invention]

[0027] Next, embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0028] A sliding member as one embodiment of the present invention is any sliding component such as a bearing, shaft, slider, slider holder, gear, washer, etc., and combinations thereof. As shown in Figure 1, a sliding member as one embodiment of the present invention is described by a sliding bearing 11 formed in a substantially cylindrical shape. A substantially cylindrical shaft 12, having substantially the same diameter as the inner diameter of the sliding bearing 11, is coaxially inserted inside the sliding bearing 11. The shaft 12 and / or the sliding bearing 11 perform horizontal motion in the axial direction or rotational or oscillating motion around the axial direction.

[0029] At least a portion of the inner surface of the sliding bearing 11 (the sliding surface of the sliding member) is formed of an aluminum bronze alloy as an embodiment of the present invention by a predetermined method, as described later. The aluminum bronze alloy may be formed on the entire inner surface of the sliding bearing 11, or it may be formed partially on the inner surface of the sliding bearing 11 in the circumferential and / or axial direction. The entire sliding bearing 11 may be formed of an aluminum bronze alloy, or an aluminum bronze alloy layer may be formed on the inside of a cylindrical member formed of a metallic or non-metallic material. In addition, depending on the required sliding performance, solid lubricants such as graphite, resin, or lead, and / or lubricants such as lubricating oil or grease may be added. The shaft 12 is made of a predetermined metallic or non-metallic material. In one embodiment of the present invention, SUS630 was used, but it is not limited to this, and predetermined metallic or non-metallic materials may be used depending on the required sliding performance such as material strength and corrosion resistance, and the usage conditions.

[0030] In one embodiment of the present invention, a sliding bearing 11 is exemplified as a sliding member, but the invention is not limited thereto. The shaft 12 may constitute the sliding member of the present invention by forming at least a portion of its outer surface (sliding surface) from an aluminum bronze alloy. Alternatively, at least a portion of the outer surface of the shaft 12 and at least a portion of the inner surface of the sliding bearing 11 may each be formed from an aluminum bronze alloy.

[0031] Although the sliding member of one embodiment of the present invention was exemplified in the shape of a sliding bearing, the sliding member of the present invention is not limited to this. As described above, the sliding member of the present invention is any sliding component such as a bearing, shaft, slider, slider holder, gear, washer, etc., and combinations thereof, in which part or all of the sliding surface is formed of the aluminum bronze alloy described later. For example, if the sliding member is a washer, then all of the washer or part or all of the sliding surface (contact surface) of the washer is formed of the aluminum bronze alloy of the present invention. Also, for example, if the sliding member is a slider or slider holder, the sliding member is formed in the shape of a plate. In this case, the entire plate-shaped sliding member may be made of aluminum bronze alloy, or only one of the sliding surfaces of the plate-shaped sliding member may be made of aluminum bronze alloy.

[0032] In one embodiment of the present invention, a sliding bearing 11, which serves as a sliding member, has a plurality of holes, grooves, or recesses formed on its sliding surface, and a solid lubricant consisting of graphite, wax, or the like is embedded and fixed in these holes, grooves, or recesses. This configuration can improve the sliding performance of the sliding member, but this configuration may be omitted depending on the required sliding performance. The plurality of holes, grooves, or recesses are formed by drilling or cutting using a drill or end mill, but they may also be formed by other means. In this case, the shape, size, area ratio of the plurality of holes, grooves, or recesses to the entire sliding surface, and fixing locations can be arbitrarily selected depending on the desired sliding performance and application. For example, they may be selected as in Japanese Patent No. 5616032, or they may be selected within the scope that is obvious to those skilled in the art.

[0033] The sliding bearing 11, as a sliding member of one embodiment of the present invention, has excellent corrosion resistance, as described later, and can therefore be used in a variety of environments. In particular, the sliding member of one embodiment of the present invention is used in seawater. However, its use is not limited to seawater, and it can also be used in environments other than seawater. For example, it can be used in applications such as high-temperature environments.

[0034] An aluminum bronze alloy constituting at least a portion of the sliding surface of a sliding member as one embodiment of the present invention is an aluminum bronze alloy composed of Cu, Al, Ni, Fe, Si and unavoidable impurities, wherein Al is 9.5% to 10.5% by weight of the total amount, Ni is 6.0% to 8.0% by weight, Fe is 4.0% to 6.0% by weight, Si is 1.0% to 2.0% by weight, and the remainder is Cu and unavoidable impurities. Furthermore, it has a structure consisting of an α phase, a coarse Fe-Si intermetallic compound with a length of 1 μm or more in the short direction, a fine κ phase separate from the Fe-Si intermetallic compound with a length of less than 1 μm in the short direction, and a trace amount of unavoidable phase, wherein the coarse Fe-Si intermetallic compound accounts for 4% to 14% of the total structure in terms of area ratio in the cross-section of the metal, and point-like and / or linear fine κ phases are dispersed throughout the entire structure.

[0035] An aluminum bronze alloy constituting at least a portion of the sliding surface of a sliding member, as one embodiment of the present invention, is formed by adding amounts of Fe and Si within the aforementioned range to the alloy composition and adjusting the amounts of Ni and Al within the aforementioned range, thereby precipitating coarse Fe-Si intermetallic compounds within the aforementioned range. ru This allows for excellent wear resistance. In this case, a Rockwell hardness of HRC17 or higher is preferred, but it is not limited to this, and a predetermined hardness can be selected depending on the sliding performance and usage conditions. Furthermore, in the case of an aluminum bronze alloy constituting at least a part of the sliding surface of a sliding member as one embodiment of the present invention, by adding amounts of Al and Ni within the above range to the alloy composition, the precipitation of the β phase is further suppressed and the corrosion resistance of the metal is improved. In this case, it is preferable that the maximum dealuminization corrosion depth, based on a corrosion test method in accordance with ISO 6509-1981, is 120 μm or less.

[0036] The method for manufacturing the aluminum bronze alloy that constitutes at least a part of the sliding surface of a sliding member as one embodiment of the present invention is not particularly limited, but it is preferable to weigh out a master alloy of nugget copper, Al shot, Fe50Al, Cu30Ni, or Cu15Si to a desired mass, melt it in a high-frequency melting furnace, and cast it by continuous casting, centrifugal casting, sand casting, etc.

[0037] In an aluminum bronze alloy constituting at least a portion of the sliding surface of a sliding member as one embodiment of the present invention, the pure metal material and alloy material used are nugget copper, Al shot, Fe50Al, Cu30Ni, and Cu15Si, but are not limited to these. The predetermined pure metal material and alloy material can be weighed and used such that, relative to the total amount, Al is 9.5% to 10.5% by weight, Ni is 6.0% to 8.0% by weight, Fe is 4.0% to 6.0% by weight, Si is 1.0% to 2.0% by weight, and the remainder consists of Cu and unavoidable impurities. For example, Fe, Ni, Si, Cu-50Fe, etc. can be used as the pure metal material and alloy material.

[0038] As a method for manufacturing an aluminum bronze alloy constituting at least a portion of the sliding surface of a sliding member as one embodiment of the present invention, the alloy was melted using a muffle furnace and then mold-cast using a predetermined mold, but is not limited thereto. As a melting method, a high-frequency induction melting furnace or the like can be used. As a casting method, continuous casting, centrifugal casting, sand casting, or the like can be used. These methods are selected within a range that is obvious to those skilled in the art in order to manufacture the desired sliding member. The melting temperature is not particularly limited, but is preferably the melting temperature of the pure metal material and alloy material used, respectively.

[0039] When processing an aluminum bronze alloy that constitutes at least a portion of the sliding surface of a sliding member as one embodiment of the present invention into the aforementioned sliding member, the sliding member can be formed using a mold or sand mold for manufacturing the sliding member during casting, but is not limited to this. An aluminum bronze alloy of any shape can be manufactured using a mold or sand mold of any shape during casting, and then the sliding member can be formed by bending, polishing and / or grinding.

[0040] Furthermore, the present invention is not limited to the embodiments described above, and can be modified or improved by those with ordinary skill in the art within the technical framework of the present invention. [Examples]

[0041] Next, embodiments of the present invention will be described in more detail with reference to experimental results.

[0042] To produce each of the aluminum bronze alloys having the compositions shown in Table 1, nugget copper, Al shot, Fe50Al, Cu30Ni, and Cu15Si were weighed in the required compositional ratios, melted at a temperature of 1200°C to 1250°C, and cast into a mold to produce samples. In this example and comparative example, the aluminum bronze alloys were cast into a mold after adding flux to the molten metal to remove metal oxides during melting. The sample weights were 300g and 3500g. The maximum dealuminization corrosion depth and microstructure were observed for the 300g sample, and the Rockwell hardness (HRC) and sliding performance were measured for the 3500g sample.

[0043] [Table 1]

[0044] Table 2 shows the area percentage of Fe-Si intermetallic compounds relative to the total area in cross-sectional diagrams of the microstructure of aluminum bronze alloys according to this example and comparative example. In the cross-sectional diagram, the area percentage of Fe-Si intermetallic compounds can be determined as follows. For each aluminum bronze alloy, a scanning electron microscope (SEM) was used to adjust the contrast so that the Fe-Si intermetallic compounds were clearly visible, and backscattered electron images (COMP images) were captured at a magnification of 500x. At this time, five arbitrary locations were selected for imaging. For each of the five backscattered electron images of the aluminum bronze alloy, the area percentage of Fe-Si intermetallic compounds was measured using image analysis software (WinROOF: manufactured by Mitani Corporation). Table 2 shows the arithmetic mean of the five area percentages.

[0045] [Table 2]

[0046] Table 3 shows the results for the maximum dealuminescence corrosion depth. The results for the maximum dealuminescence corrosion depth allow for a comparison of corrosion resistance. Here, the measurement of the maximum dealuminescence depth was performed based on the corrosion test method compliant with ISO 6509-1981.

[0047] [Table 3]

[0048] As shown in Table 3, the aluminum bronze alloys of this example (Examples 1-5) exhibit superior corrosion resistance compared to the comparative aluminum bronze alloys (Comparative Examples 4-7), as evidenced by their smaller maximum dealuminization corrosion depth and average dealuminization corrosion depth.

[0049] Figures 2 to 4 are optical microscope images showing the microstructure of aluminum bronze alloys corresponding to Example 2, Comparative Example 1, and Comparative Example 4, respectively. The contrast of these images has been adjusted for easier identification. As shown representatively in Figure 2, in each figure, the relatively bright areas represent the α phase in the aluminum bronze alloy. The α phase is generally a soft structure, and a high proportion of the α phase impairs the wear resistance and high load resistance of the metal. In each figure, the dark areas with a length of 1 μm or more in the short direction are roughly circular or elliptical areas representing coarse Fe-Si intermetallic compounds, while the dark areas with a length of less than 1 μm in the short direction are linear or dot-like areas representing fine κ phases distinct from Fe-Si intermetallic compounds.

[0050] As shown in Figure 2, the aluminum bronze alloy obtained in Example 2 shows uniformly dispersed and precipitated coarse Fe-Si intermetallic compounds. In addition, a fine κ phase, separate from the Fe-Si intermetallic compounds, is dispersed throughout the entire structure, forming the matrix together with the α phase. Although the presence of a β phase in the matrix is ​​assumed in addition to the α phase, the small depth of dealuminization corrosion (maximum dealuminization depth is 120 μm or less) indicates that no β phase is formed within the α phase, or that it is not present to the extent that it impairs corrosion resistance. The precipitation of fine κ phase and coarse Fe-Si intermetallic compounds in the matrix maintains the hardness of the matrix and causes the precipitation of coarse, hard regions within the matrix. As a result, the coarse intermetallic compounds do not easily detach during sliding, and excellent sliding performance is observed, as will be described later. Examples 1 and 3-5 showed similar characteristics to Example 2.

[0051] On the other hand, as shown in Figure 3, the aluminum bronze alloy of Comparative Example 1 contains coarse Fe-Si intermetallic compounds of 1 μm or larger, as shown in the example in Figure 2. 2 It was found to be less compared to [the other group]. Although not shown in the figures, Comparative Examples 2-3 were similar to Comparative Example 1. Also rough There were few large Fe-Si intermetallic compounds. Because there were few coarse Fe-Si intermetallic compounds and a high proportion of the α phase, the aluminum bronze alloys of Comparative Examples 1-3 are as shown in the table below. 5As described above, the hard intermetallic compound easily detaches during sliding, significantly impairing the sliding performance. Furthermore, the hardness (Rockwell hardness) is lower compared to Examples 1-5, resulting in reduced wear resistance and resistance to high loads when used as a sliding component.

[0052] Furthermore, as shown in Figure 4, the aluminum bronze alloy of Comparative Example 4 shows uniformly dispersed precipitates of coarse Fe-Si intermetallic compounds. Although not shown, the same can be confirmed for each of Comparative Examples 5 to 7. On the other hand, Comparative Example 4~7 Since each of the aluminum bronze alloys has a large dealuminization corrosion depth (more than 120 μm), it is assumed that a β phase is formed in the matrix. Because the β phase is significantly formed, the aluminum bronze alloys of Comparative Examples 4-7 are shown in the table. 3 As shown above, the depth of dealuminization corrosion is greater compared to Examples 1-5, resulting in reduced corrosion resistance and consequently, durability.

[0053] The sliding performance of the aluminum bronze alloy sliding member of this embodiment was tested using a seawater journal test under the conditions shown in Table 4 below, and the coefficient of friction, bearing wear, and shaft wear were measured. For comparison, Comparative Example 1 was also tested. ~7 Similar tests were conducted on the following: Examples 1-5 and Comparative Example 1- 7 Each of the sliding members, consisting of the above composition, takes the form of a sliding bearing 11, as described in the embodiment of the present invention. The sliding bearing 11 is formed in a substantially cylindrical shape. The sliding bearing 11 of this embodiment has an inner diameter of 60 mm, an outer diameter of 75 mm, and a length of 30 mm. In addition, a solid lubricant is embedded in a part of the sliding surface of the sliding bearing 11 of this embodiment. As the solid lubricant, a PTFE-based solid lubricant SL464 (manufactured by Oiles Industries Co., Ltd.) is used.

[0054] [Table 4]

[0055] In the seawater journal test, as shown in Figure 1, with the shaft 12 inserted into the sliding bearing 11 in seawater, a load perpendicular to the axis of the shaft 12 is applied to the sliding bearing 11 so that the inner surface (sliding surface) of the sliding bearing 11 presses against the outer surface of the shaft 12 with the surface pressure shown in Table 4. At the same time, the shaft 12 is oscillated around its axis at the speed shown in Table 4, and the coefficient of friction of the sliding bearing 11, the amount of bearing wear, and the amount of shaft wear are measured.

[0056] Table 5 shows the test results for the friction coefficient, bearing wear, and mating shaft wear of the aluminum bronze alloy sliding bearing 11 in each example and comparative example, conducted under the conditions shown in Table 4 in a seawater journal test. Furthermore, Table 5 shows the Rockwell hardness (HRC) to examine the load-bearing capacity as a sliding member. The friction coefficient is the friction coefficient at the end of the seawater journal test, and the wear of the shaft 12 and the wear of the sliding bearing 11 are also values ​​at the end of the seawater journal test. Also, at this time, in Example 3, the lubrication conditions another To confirm the sliding performance, the process was divided into cases with and without lubricant, and the sliding performance was examined. Grease was used as the lubricant.

[0057] [Table 5]

[0058] The friction coefficient of the aluminum bronze alloy sliding bearings 11 of Examples 1 to 5 used in this embodiment was 0.13 or less at the end of the test, making them suitable for use as sliding members. Furthermore, the wear amount of the aluminum bronze alloy sliding bearings 11 of Examples 1 to 5 was 0.04 mm or less, and the Rockwell hardness was HRC17 or higher, indicating excellent durability and wear resistance under high loads as sliding members. On the other hand, as shown in Table 5, Comparative Examples 1 to 3 had a friction coefficient of 0.16 or higher at the end of the test, which is higher than that of Examples 1 to 5, and leaves room for improvement in sliding performance compared to Examples 1 to 5. Furthermore, in Comparative Examples 1 to 3, the wear amount of the sliding bearing 11 at the end of the test exceeded 0.08 mm, and the Rockwell hardness was less than HRC17. Since the wear amount of the sliding bearing 11 is more than twice that of Examples 1 to 5, Comparative Examples 1 to 3 have remaining issues with durability and wear resistance under high loads, making them unsuitable for use as sliding members. Furthermore, in Example 3, the sliding performance was confirmed with and without grease (see Table 5). The coefficient of friction of the sliding bearing 11 when grease was not applied to the sliding bearing 11 (0.13) was the same as the coefficient of friction of the sliding bearing 11 when grease was applied to the sliding bearing 11 (0.1 1) The change was small in comparison. On the other hand, the amount of wear of the sliding bearing 11 when grease was not applied to the sliding bearing 11 (0.028 mm) was less than the amount of wear of the sliding bearing 11 when grease was applied to the sliding bearing 11 (0.015 mm). m) It was larger in comparison, but the amount of bearing wear in comparative examples 1-3 ( 0.087mm~ 0.124m m) In comparison, it was significantly smaller. Therefore, the sliding member made of the aluminum bronze alloy of the present invention has excellent sliding performance regardless of the presence or absence of lubricant, and is suitable for use as a sliding member in environments where lubricant cannot be used extensively.

[0059] Figure 5 shows the relationship between the area ratio of the Fe-Si intermetallic compound relative to the total area, calculated from optical microscope images showing the microstructure of aluminum bronze alloys in Examples 1-5 and Comparative Examples 1-3, and the friction coefficient and bearing wear amount obtained in Table 5. Here, the horizontal axis represents the area ratio of the Fe-Si intermetallic compound relative to the total area, the left vertical axis represents the bearing wear amount, and the right vertical axis represents the friction coefficient. Furthermore, numbers enclosed in white circles indicate the friction coefficient of the example corresponding to that number, numbers enclosed in black circles indicate the bearing wear amount of the example corresponding to that number, numbers enclosed in white squares indicate the friction coefficient of the comparative example corresponding to that number, and numbers enclosed in black squares indicate the bearing wear amount of the comparative example corresponding to that number. In general, under high surface pressure, the true contact area increases, making it difficult to maintain the lubricating film, so the friction coefficient and bearing wear amount tend to increase. To prevent this effect, it is necessary to increase the area ratio of the Fe-Si intermetallic compound and decrease the true contact area. In particular, as shown in Figure 5, when the area ratio of Fe-Si intermetallic compounds is 4% or more of the total area, the effects of reducing the coefficient of friction and the amount of bearing wear become significantly apparent. When the area ratio of Fe-Si intermetallic compounds is less than 4% of the total area, the coefficient of friction increases, and the amount of bearing wear also increases. On the other hand, when the Fe-Si intermetallic compounds exceed 14%, wear on the mating shaft becomes significant, and the sliding performance cannot be maintained for a long period of time. Furthermore, the degree of freedom during processing is limited by the hardness. Therefore, in the aluminum bronze alloy of the present invention, the area ratio of Fe-Si intermetallic compounds is preferably in the range of 4% to 14%, and more preferably in the range of 4.7% to 13.2%.

[0060] Figure 6 shows the relationship between the Rockwell hardness (see Table 5) of the sliding bearings 11 made of aluminum bronze alloy in Examples 1-5 and Comparative Examples 1-3, and the coefficient of friction and bearing wear obtained in Table 5. Here, the horizontal axis represents the Rockwell hardness of the sliding bearing 11, the left vertical axis represents the bearing wear, and the right vertical axis represents the coefficient of friction. Furthermore, the numbers enclosed in white circles indicate the coefficient of friction for the corresponding example, the numbers enclosed in black circles indicate the bearing wear for the corresponding example, the numbers enclosed in white squares indicate the coefficient of friction for the corresponding comparative example, and the numbers enclosed in black squares indicate the bearing wear for the corresponding comparative example. In general, under high surface pressure, the true contact area increases, making it difficult to maintain the lubricating film, so the coefficient of friction and bearing wear tend to increase. To prevent this effect, it is necessary to increase the area ratio of the Fe-Si intermetallic compound, reduce the true contact area, and increase the hardness of the matrix to prevent the Fe-Si intermetallic compound from falling off. Referring to Figure 6, a significant reduction in the coefficient of friction and bearing wear is observed when the Rockwell hardness reaches HRC17 or higher. In particular, in Comparative Examples 1 to 3, the Rockwell hardness is less than HRC17, resulting in a high coefficient of friction of 0.16 and bearing wear of 0.08 mm or more. Therefore, from the viewpoint of maintaining sliding performance, the Rockwell hardness of the aluminum bronze alloy of the present invention is preferably HRC17 or higher, and more preferably HRC17.5 or higher.

[0061] The present invention has been described above based on the examples. According to the aluminum bronze alloy of the present invention, the dealuminization corrosion depth is smaller compared to other aluminum bronze alloys, thus maintaining its properties as an aluminum bronze alloy and, consequently, as a sliding member, even in seawater and other chemically active environments. Furthermore, it possesses sufficient hardness and demonstrated sufficient sliding performance in seawater journal tests, making it suitable for sliding members with high load resistance and wear resistance. [Explanation of Symbols]

[0062] Plain bearing 11, shaft 12

Claims

1. An aluminum bronze alloy comprising copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), silicon (Si), and unavoidable impurities, For the entire amount, Al is 9.5% by weight or more and 10.5% by weight or less. Ni is 6.0% by weight or more and 8.0% by weight or less. Fe is 4.0% by weight or more and 6.0% by weight or less. The Si content is 1.0% by weight or more and 2.0% by weight or less. The remainder is Cu and unavoidable impurities. The structure consists of an α phase, a coarse Fe-Si intermetallic compound with a length of 1 μm or more in the short direction, a κ phase separate from the Fe-Si intermetallic compound, a fine κ phase with a length of less than 1 μm in the short direction, and a trace amount of unavoidable phase. The aforementioned coarse Fe-Si intermetallic compound accounts for 4% to 14% of the total area ratio in the cross-section of the metal relative to the overall structure. Fine, punctate or linear κ-phase particles are dispersed throughout the tissue. The Rockwell hardness is HRC 17 or higher. An aluminum bronze alloy characterized by having a maximum dealuminescence corrosion depth of 120 μm or less in a corrosion test method compliant with ISO 6509-1981.

2. The aluminum bronze alloy according to claim 1, For the entire amount, Al is 9.5% by weight or more and 10.5% by weight or less. Ni is greater than 7.0% by weight and 8.0% by weight or less. Fe is 4.0% by weight or more and 6.0% by weight or less. The Si content is 1.0% by weight or more and 2.0% by weight or less. An aluminum bronze alloy characterized in that the remainder consists of Cu and unavoidable impurities.

3. A sliding member characterized in that the sliding surface is formed of the aluminum bronze alloy described in claim 1 or 2.

4. A sliding member according to claim 3, A sliding member characterized in that a plurality of holes, grooves, or recesses are formed on the sliding surface, and a solid lubricant is embedded and fixed in these holes, grooves, or recesses.

5. A sliding member according to claim 3 or 4, A sliding member characterized in that part or all of the sliding member is used in seawater.

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