KR100940117B1 - Fe based alloy for self-lubricating bearing, manufacturing method for the same and self-lubricating bearing manufactured therefrom - Google Patents

Abstract

PURPOSE: Fe alloy for self-lubricating bearing, a manufacturing method thereof, and self-lubricating bearing manufactured therefrom are provided to reduce the manufacturing cost, and to increase service life. CONSTITUTION: Fe alloy for self-lubricating bearing comprises Cu 12~16 weight%, C 0.35~0.6 weight%, Mn 0~8 weight%, Cr 0.5~2 weight%, Sn 0.5~2 weight%, rest Fe, and inevitable impurities. Mn+10C is 6~11 weight% or less, and Cu+0.6Cr is 23 weight% or less. Molten metal of Mn+10C 6~11 weight% or less, and Cu+0.6Cr 23 weight% or less is casted.

Description

Fe alloy for self-lubricating bearing, manufacturing method and self-lubricating bearing manufactured therefrom {FE BASED ALLOY FOR SELF-LUBRICATING BEARING, MANUFACTURING METHOD FOR THE SAME AND SELF-LUBRICATING BEARING MANUFACTURED THEREFROM}

The present invention relates to a Fe alloy for self-lubricating bearings and a method for manufacturing the same, and more particularly, to be used in self-lubricating bearings that can secure long life even when high cyclic loads are applied in a state in which lubricant is not supplied or in solid lubrication conditions. It relates to a Fe-based alloy that can be and a method of manufacturing the same.

Parts that operate at low speeds and high loads (eg 80 MPa or more) include bearings, gears, wear-resistant plates, slippers, worm wheels, etc. These components commonly include self-lubricating bearing alloys for low speed, high loads. It is used a lot. Self-lubricated bearings are bearings that operate in low-speed, high-load environments where lubricants cannot be supplied. Since lubricants are not supplied, they may be exposed to more severe abrasion environments, requiring high wear resistance and lubricity.

Conventionally, brass alloys (for example, C86300) were mainly used as the bearing alloys for low speed and high loads, and special solid lubricants such as graphite, PTFE, and MoS2 were applied to the surface of the bearings made of the castings. It is manufactured to be suitable for use in extreme loading conditions. However, as the industry develops, there is a continuous demand for improving the efficiency of equipment, and therefore, the environment in which the bearings are used is not only harsher but also required to be more resistant to wear.

In addition, since the price of brass casting, which is the main material of the self-lubricating bearing made of the brass casting, rises steeply from year to year, the industry has come to search for alternative materials with higher price competitiveness and improved lubrication performance. As an alternative to this, a method of improving the lubrication property by coating a solid lubrication layer on the surface of the Fe-based alloy has been proposed. However, when the wear resistance is improved only by the solid lubrication layer, the service life is determined according to the life of the lubrication coating layer. Therefore, it is difficult to expect a longer life bearing, and the general lubrication coating layer has a weak bonding force with the alloy. At low speed and high load conditions, the lubricating coating layer could be easily peeled off, which may cause a problem in the reliability of the bearing.

Another option is oil-impregnated sintered bearings to hold oil. The porous bearing may be manufactured by a method such as sintering, such a sintered product is not suitable for the mechanical parts of the plate or ring type because there is a problem that is susceptible to high reciprocating oscillation or intermittent motion. In addition, sintered products had a problem that it is difficult to secure price competitiveness other than special products such as automobiles, home appliances and communication device parts, and small gears.

According to one aspect of the present invention, a novel Fe-based alloy for self-lubricating bearings having a sufficient lifespan even under high cyclic loads and having low manufacturing costs may be provided.

The alloy for bearings of this invention for solving the said subject is characterized by containing 12 to 17 weight% of Cu.

At this time, in order to further improve the effect of the Cu addition, C: 0.35 ~ 0.6% by weight, Mn: more than 0 to 8% by weight, Cr: 10 to 15% by weight, Sn: preferably further comprises 0.5 to 2% by weight Do.

In addition, in order to further improve the lubrication performance due to the Cu precipitated phase and to facilitate movement to the surface of the Cu precipitated phase, it is more preferable to satisfy the relationship of Mn + 10C: 6-11 wt% and Cu + 0.6Cr: 23 wt% or less. It is advantageous.

The manufacturing method of the bearing alloy which is another aspect of this invention is characterized by casting by manufacturing the molten metal which satisfy | fills the composition condition mentioned above.

In addition, the self-lubricating bearing having high lubricating performance in a non-lubricating environment or similar environment, which is another aspect of the present invention, has a Cu precipitated phase therein and the hardness of Fe-based metal measured by a micro-Vickers hardness tester (a). And the ratio (a / b) of the hardness (b) of the Cu precipitated phase is 2 to 2.5.

The self-lubricating bearing preferably has an austenite ratio of 99 vol% or more, as measured by a Fe scope metal (Feritscope, MP-30E).

The self-lubricating bearing made from the Fe-based alloy provided according to the present invention can not only have a high life under normal lubricating environment but also in a non-lubricating environment or a solid lubricating environment, and the Fe alloy can be produced by a casting method. It has the advantage that it can be manufactured at low cost.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention have solved the above-described prior art and studied alloys capable of producing bearings with sufficient lubrication performance even under high cyclic loads. When properly controlled and controlled under conditions such that Cu precipitated phases are formed therein, the present inventors have found that bearings that can be used for a long time under a lubricating environment or a solid lubricating environment as well as a normal lubricating environment have been found and led to the present invention. .

That is, the alloy of the present invention has a composition containing Cu as the Fe-based alloy. Here, the Fe-based alloy means that Fe is the main component and may include additional components required according to the use of the alloy.

When Cu is included in the Fe-based alloy in the composition range as described above, as shown in Fig. 1, the Cu phase is precipitated inside. The precipitated Cu phase first reduces the adhesion between the iron-based metals on the wear surface to use the bearing. In addition to improving the adhesion resistance that does not occur in the environment, the wear performance can also be improved.

In addition, the Cu phase present in the Fe alloy is different from the degree of deformation of Fe, which is pushed to the wear surface under the stress environment in which the bearing is used and occupies a larger area than the surface before wear. The large amount of the second phase thus distributed serves as a protective film with the counterpart material. This phenomenon can be expressed as a so-called smearing phenomenon, the process of which is shown in FIG. 2.

In this process, the Cu precipitated phase, which remains largely on the wear surface, prevents the direct contact between the mating material and the bearing matrix, as compared with the conventional Fe alloy, in which copper alloys of the same type easily adhere due to the absence of the Cu precipitated phase. Further, as the wear progresses, the smeared Cu precipitates and the iron matrix produce wear debris, which are crushed by continuous friction and eventually oxidized to form fine oxide debris. have. These fine oxide debris agglomerates and remains on the wear surface, thereby preventing direct contact between the metal and the metal to prevent adhesion, thereby improving the lubrication characteristics of the bearing.

Cu, which plays an advantageous role as described above, is preferably contained 12 to 17% by weight in the Fe-based alloy. That is, Cu needs to be formed beyond the solubility of Fe alloy because Cu must form a precipitated phase. Therefore, Cu should be included in the Fe-based alloy more than 12% by weight. However, the Cu precipitated phase is important to be precipitated as the second phase, but it is also important that the size is evenly distributed. If Cu is present in an excessive amount, an excessively coarse Cu precipitated phase may be formed. It is not preferable because it is very uneven and the lubrication characteristics of the bearing due to this phenomenon is uneven. Therefore, the Cu content is more preferably limited to 17% by weight or less.

Therefore, the advantageous composition of the Fe alloy for self-lubricating bearing of the present invention is a composition containing 12 to 17% by weight of Cu.

The remaining components added as long as the above conditions are met may be adjusted and added within the ranges commonly used in the bearing manufacturing field. However, according to the results of the present inventors, the Cu component is limited within the range defined in the present invention in order to more uniformly control the Cu precipitated phase or further improve the smearing effect of the Cu precipitated phase to further improve the wear resistance characteristics of the bearing. At the same time, it is more preferable to limit the elements such as C, Mn, Sn, Cr, and the like to the following ranges.

C: 0.35 to 0.6% by weight, Mn: over 0 to 8% by weight

C and Mn are austenite stabilizing elements, and when C or Mn is added, fatigue fracture characteristics of the bearing may be improved. In addition, as described above, in order for the Cu precipitated phase to be pushed out to the surface of the iron alloy by the smearing phenomenon, the iron alloy must have a certain deformation capacity. When the austenite phase is included by containing C and Mn, It is possible to secure such deformation capacity. In the present, according to a study by the inventors the base metal of Fe hardness (a) and Cu precipitated hardness (b) on the alloy has a micro Vickers hardness of the reference, each of 250 ~ 300Hv _0.025, and _0.025 about 100 ~ 120Hv the ratio of the two values ( When the a / b) is 2 to 2.5 times, the above-mentioned smearing effect can sufficiently occur. If these components are insufficient, austenite is not sufficiently stabilized, and martensite is formed in excess of 1% by volume (a fraction measured by Ferriscope MP-30E) when manufactured by bearing. In this case, the hardness of the base metal is rapidly increased, and thus, it is difficult to obtain a smearing effect due to the difference in the degree of deformation of the precipitated phase and the base metal.

Especially, since C plays a role of lowering the solubility of Cu in addition to the above-mentioned effects, it is easy for Cu to exist as a precipitated phase. In view of this point, C is preferably included at 0.35% by weight or more. However, when the content of C is excessive, hard carbides such as Cr7C3 are formed to increase the hardness of the base metal, which adversely affects the formation of a protective film by Cu particles. Therefore, C is preferably added at 0.6% by weight or less. In addition, Mn does not need to be added because an austenite stabilization effect by C can be obtained even if an element or Mn added for austenite stabilization does not exist. However, when excessively added, since it adversely affects the wear resistance, the amount of Mn added is limited to more than 0 to 8% by weight.

Cr: 10-15 wt%

Cr is an element that serves to lower the solubility of Cu in the iron base metal. That is, when Cr is added in an appropriate amount, more Cu precipitated phases can be formed even at the same Cu content. Therefore, in order to obtain the above advantageous effect by adding Cr, Cr is preferably added at least 10% by weight, and more preferably at least 12% by weight, considering the corrosion resistance in the environment in which the bearing is used. However, when Cr is excessively added, the precipitated Cu particles not only become coarse, but ferrite phases that are disadvantageous to abrasion resistance may be generated in the base metal. Therefore, the upper limit is preferably set to 15% by weight. The more preferable range of Cr which does not produce Cr7C3 etc. which are high hardness carbides is 13 weight% or less.

Sn: 0.5-2 wt%

Sn is preferably added in an amount of 0.5% by weight or more, because it is an element that helps to form a large amount of precipitated Cu particles without lowering the solid solution of Cu in the iron matrix. However, when Sn is added in an amount of 2% by weight or more, it is difficult to control the size and distribution of the precipitated Cu particles and also increase the hardness by changing the phase of the precipitated Cu particles. The hardness difference prevents the Cu particles from slipping on the surface. Therefore, the content of Sn is preferably in the range of 0.5 to 2% by weight.

In addition, the above components added to the bearing alloy of the present invention more preferably satisfy the above-described content ranges and at the same time limit the relationship of the respective components.

Mn + 10C: 6 ~ 11, where Mn and C each represent the content (% by weight) of the element

Mn and C are complementary because they act as austenite stabilizing elements of the base metal and control the deformation of the base metal and Cu. Therefore, when a large amount of Mn is added, C may be added in a relatively small amount. In addition, when Mn and C are added in excess at the same time, since high-strength carbides due to C may be generated, the amount of Mn and C is more preferably determined in consideration of this. According to the findings of the inventors of the present invention, Mn and C more preferably satisfy the range shown in FIG. 3. Therefore, as a result of obtaining the formula to meet the range of Mn + 10C is to set the range of 6 to 11% by weight.

Cu + 0.6Cr: 23 or less (where Cu and Cr are the content of the corresponding elements (% by weight))

As described above, Cr is an element that serves to easily form the precipitated phase of Cu. Therefore, when a large amount of Cr is added, even if only a small amount of Cu is present, the precipitated phase can be easily formed. However, when a large amount of Cr and Cu are added at the same time, the size of the Cu precipitated phase may be coarse. Therefore, when a large amount of Cr is added, the amount of Cu added needs to be reduced. According to the results of the present inventors, it is more preferable that such a relationship between Cr and Cu corresponds to an area surrounded by I, II, III, and IV points as shown in FIG. 4. Therefore, it is preferable that Cu + 0.6Cr has a value of 23 weight% or less.

It is preferable that the bearing steel alloy as described above is manufactured by a casting method. That is, when manufacturing the bearing steel alloy which has the composition of this invention by the conventional sintering method, since it is hard to expect improvement of the self-lubrication performance by the smearing phenomenon mentioned above, it is preferable, and a manufacturing cost also increases.

The bearing steel alloy as described above may be manufactured by molten metal in a conventional manner, and then may be cast by various methods such as ingot casting and continuous casting. In this case, as a more preferable method for producing the molten metal, it is preferable to dissolve the molten metal in an inert atmosphere or a vacuum atmosphere so that the components of the alloy are not oxidized, and for this purpose, it is more preferable to use a vacuum induction furnace or the like.

Bearing steel alloy of the present invention that satisfies the above conditions can then be processed into a bearing form and then subjected to additional processing as necessary, and then produced as a bearing, the manufacturing process is by a conventional bearing manufacturing process. At this time, the bearing of the present invention should be able to be pushed out to the bearing wear surface by the smearing phenomenon as described above, for this purpose, it is necessary that the hardness of the base metal and the Cu precipitated phase. The bearing of the present invention preferably has a ratio (a / b) of 2 to 2.5 when the hardness (a) of the base metal and the hardness (b) of the Cu precipitated phase are measured with a micro-Vickers hardness tester. When the hardness ratio is lower than the above range, there is little difference between the degree of deformation of the soft phase and the hard phase, so that the smearing phenomenon hardly occurs. On the other hand, if the ratio is excessive, the hard phase is excessively hardened, so that deformation hardly occurs, and in this case, smearing is unlikely to occur.

Therefore, the bearing of the present invention controls the hardness ratio (based on the micro Vickers hardness) of the base alloy and the precipitated phase in the internal structure while maintaining the composition of the Fe-based bearing alloy described above as it is 2 to 2.5.

In order to satisfy the hardness standard, the base metal of the bearing of the present invention, that is, the base metal of the Fe alloy except for the Cu precipitated phase is preferably 99% by volume or more in the austenite phase before use. That is, the Fe alloy constituting the bearing is composed of austenite or martensite structure in the bearing state, when the ratio of martensite structure increases, the hardness is excessively increased, so that smearing phenomenon hardly occurs. Therefore, the ratio of austenite phase is set to 99 volume% or more. There may be various methods for determining the ratio of the austenite phase, but in the present invention, the value when measured with a Ferritscope MP-30E is determined based on the reference.

(Example)

To prepare a Fe alloy with the composition shown in Table 1 and to compare the wear characteristics.

division Composition (% by weight) Experimental condition (0.05m / s, 10min, no lubrication) Iron (Fe) Copper (Cu) Chromium (Cr) Manganese (Mn) Carbon (C) Tin (Sn) 1ksi 2ksi Abrasion amount (mg) Abrasion amount (mg) Comparative Example 1 Balance 15 12 15 0.1 0 217.8 467.2 Comparative Example 2 Balance 15 12 10 0.2 0 12.1 100.4 Comparative Example 3 Balance 15 12 6 0.3 0 0.1 20.2 Comparative Example 4 Balance 13 12 4 0.3 One 0.1 40.5 Comparative Example 5 Balance 14 12 0 0.35 One 10.2 38.1 Comparative Example 6 Balance 14 17 4 0.35 0 17.3 82.8 Comparative Example 7 Balance 17 8 4 0.35 0 5.7 48.7 Inventive Example 1 Balance 14 12 3 0.35 One 0.1 0.1 Inventive Example 2 Balance 13 12 3 0.35 One 0.1 5.1 Inventive Example 3 Balance 13 12 3 0.35 2 0.1 0.1 Inventive Example 4 Balance 14 12 3 0.4 One 0.1 0.1 Inventive Example 5 Balance 13 12 3 0.4 2 0.1 0.1 Inventive Example 6 Balance 14 12 2 0.45 One 0.1 0.1 Inventive Example 7 Balance 13 12 2 0.45 One 0.1 0.1 Inventive Example 8 Balance 14 12 2 0.5 One 0.1 16.4 Inventive Example 9 Balance 13 12 2 0.5 One 5.1 7.2 Inventive Example 10 Balance 14 12 2 0.6 One 0.1 0.1 Conventional example (C86300) Cu: remainder, Al: 5, Fe: 3, Mn: 3, Zn: 25 5.2 20.4 Pin (SUJ2, bearing steel, HRc 60) Fe balance, Cr: 1.5, Si: 0.3, Mn: 0.5, C: 1 No amount of pin wear under experimental conditions.

Comparative Examples 1 to 3 of the test composition show a case where the content of carbon and tin is less than the range defined by the present invention. In addition, the comparative example 4 shows the case where carbon falls below the range prescribed | regulated by this invention, and the comparative example 5 shows the case where manganese content falls under the range prescribed | regulated by this invention. Comparative Example 6 shows a case where the content of chromium is excessive beyond the range defined in the present invention and the content of tin is less than that, and Comparative Example 7 shows a case where the content of chromium and tin is less. The conventional example is a case where the composition of the C86300 alloy, which is a brass bearing alloy, which has been widely used in the past.

Each alloy specimen was prepared using high frequency induction heating in an inert atmosphere of Ar gas. The cast specimens were each processed to a size of 30 mm wide by 30 mm high and 5 mm wide to measure wear resistance. Before the test, the surface was polished using # 2000 SiC abrasive paper so that the surface roughness Ra was 0.2 rm or less as measured by the surface roughness. Pin, which is a relative material of the disk, is made of commonly used high carbon chromium special steel (JIS SUJ2, hardness 60HRc).

Bearing alloy specimens prepared in the composition of Table 1 are installed in pin-on-disk apparatus, respectively, contact stress 1ksi (6.7MPa) ~ 3ksi, rotational speed 60rpm (0.05m / s) The wear test was carried out while changing the contact stress for 5 minutes under no lubrication condition. After the test, the amount of wear was measured and the results are also shown in Table 1. Among them, the bearing manufactured under the condition of Inventive Example 4 showed the best wear resistance even under high load under the condition of no lubrication. In addition, it can be seen that most of the inventive examples exhibit much higher wear resistance than the high-strength brass casting (C86300, a conventional example) which is currently commercially available. However, the comparative examples were judged to be suitable for use as a bearing in a non-lubricating condition because the wear amount is very severe as compared with the conventional example.

In order to confirm the role of the formation of the Cu precipitated phase on the wear resistance of the bearing, the precipitated phase distribution was confirmed under a microscope with respect to the Comparative Examples and Inventive Examples and the results are shown in Table 2 below.

division Composition (% by weight) Particle shape Iron (Fe) Copper (Cu) Chromium (Cr) Manganese (Mn) Carbon (C) Tin (Sn) Particle Size Distribution (㎛) Shape of particles Comparative Example 1 Balance 15 12 15 0.1 0 10-30 Round Comparative Example 2 Balance 15 12 10 0.2 0 10-40 Round Comparative Example 3 Balance 15 12 6 0.3 0 10-60 Round Comparative Example 4 Balance 13 12 4 0.3 One 10-60 Round Comparative Example 5 Balance 14 12 0 0.35 One 10-80 Round Comparative Example 6 Balance 14 17 4 0.35 0 10-100 Round Comparative Example 7 Balance 17 8 4 0.35 0 10-150 Round Inventive Example 1 Balance 14 12 3 0.35 One 10-90 Round Inventive Example 2 Balance 13 12 3 0.35 One 10-80 Round Inventive Example 3 Balance 13 12 3 0.35 2 10-90 Round Inventive Example 4 Balance 14 12 3 0.4 One 10-100 Round Inventive Example 5 Balance 13 12 3 0.4 2 10-90 Round Inventive Example 6 Balance 14 12 2 0.45 One 10-100 Round Inventive Example 7 Balance 13 12 2 0.45 One 10-90 Round Inventive Example 8 Balance 14 12 2 0.5 One 10-100 Round Inventive Example 9 Balance 13 12 2 0.5 One 10-100 Round Inventive Example 10 Balance 14 12 2 0.6 One 10-100 Round

As described above, Table 2 shows the results of investigation of particle diameter, shape and distribution of the second phase mainly composed of Cu according to the composition. As can be seen from the table, the particle diameter was highly affected by the C content. That is, as the C content increased, the particle diameter tended to increase. In the case of the comparative example, the particle diameter was less than 70 µm, which was somewhat insufficient to obtain the effect of improving the lubricating performance by smearing. However, in the case of the invention examples, all had a maximum particle diameter of 70 μm or more and 100 μm or less, and this formed a protective film that was not easily broken even under high loads due to smearing, even though the bearings were operated under low lubrication conditions under low loads. It can be a cause of having good lubrication performance. Referring to the results of Table 2, it was determined that the maximum particle diameter is about 50 ~ 90㎛. In other words, if the diameter of the second phase is too large, smearing phenomenon due to deformation of the matrix is less likely to occur, and normal wear phenomenon occurs. On the contrary, if the diameter is too small, the amount supplied to the wear surface is so small that a lubricating effect is expected. Difficult to do Therefore, as can be seen also in Table 1, the wear performance is poor in the case of Comparative Examples 1 to 4, in which the particle diameter is too small, and in Comparative Example 7, in which the particle diameter is excessive.

 Also, in general, it is very difficult to uniformly distribute Cu particles precipitated in the iron matrix (Fe-matrix) through casting because Fe and Cu are separated from each other in a molten state. However, the present invention has been made possible by controlling the content of each element in order to uniformly distribute the coarse precipitated Cu particles in the matrix.

Figure 5 is a photograph of the wear surface after the wear test for the bearing prepared in Example 4 and the prior art meeting the composition conditions of the present invention. The experimental condition is the result of the surface observation after abrasion test for 5 minutes in the non-lubricating condition by the pin-on-disk method at the rotational speed of 60rpm (0.05cm / s) at 1ksi (6.7MPa) contact stress. The pin used the thing of the conditions shown in the said Table 1. As shown in FIG. 5, in the case of the invention, a protective layer made of an oxide film is formed on the surface to improve wear resistance. As a result, the wear surface is smooth, whereas in the case of the high-strength brass C86300 alloy, deep wear is generated.

FIG. 6 shows the wear surface of the bearing of Inventive Example 4, which was subjected to the test, using a scanning electron microscope (SEM). A large part of the wear surface is covered with a smooth oxide film, which shows that the wear performance is affected.

In addition, in order to observe the effect of the phase fraction on the lubrication characteristics of the bearing, the martensite phase fraction of the bearings prepared in each of Comparative Examples and Inventive Examples was measured ten times. In Comparative Examples 1 to 3, the hardness level showed an appropriate range. However, as described above, the size of the Cu precipitated phase was so small that it was difficult to expect sufficient lubricating performance. However, in the case of Comparative Example 5, as shown in Table 3, the ratio of martensite was 8 vol%, and in the case of Comparative Example 6, it was 16 vol%. In this case, the structure of the base metal is so hard that deformation cannot easily occur, and thus, the Cu precipitated phase, which is a soft structure, is hard to be pushed to the wear surface, thereby reducing the lubrication performance as shown in Table 1.

collection One 2 3 4 5 6 7 8 9 10 Average Standard Deviation Micro Hardness (Hv0.025) matrix Precipitated statue Comparative Example 1 0.6 1.2 0.8 0.9 0.6 1.1 0.3 0.7 0.6 0.8 0.76 0.26 263.4 107.2 Comparative Example 2 0.3 0.4 0.9 0.8 0.7 0.6 0.4 0.3 0.4 0.7 0.55 0.22 252.1 106.3 Comparative Example 3 0.2 0.1 0.4 0.7 0.6 0.3 0.5 0.8 0.4 0.3 0.43 0.22 252.9 109.2 Comparative Example 4 0.7 0.5 1.3 0.9 0.4 0.8 0.9 0.9 0.6 1.2 0.82 0.29 248.5 102.9 Comparative Example 5 6.8 7.2 8.2 7.3 7.8 7.9 7.2 10.2 8.7 9.6 8.09 1.11 384.2 106.3 Comparative Example 6 14.2 15.8 19.2 16.1 15.2 14.2 15.2 17.8 16.8 17.2 16.2 1.60 433.2 112.8 Comparative Example 7 0.2 0.3 0.4 0.5 0.8 0.4 0.9 0.2 0.4 0.5 0.46 0.23 262.4 106.7 Inventive Example 1 0.4 0.8 0.9 One 0.4 0.9 0.9 0.7 0.8 1.3 0.81 0.27 250.2 107.5 Inventive Example 2 0.7 0.6 0.4 0.8 0.7 0.9 One 0.9 0.4 0.6 0.7 0.21 254.2 111.2 Inventive Example 3 1.2 0.7 0.5 0.8 0.9 0.7 0.6 0.5 0.8 0.9 0.76 0.21 232.8 98.7 Inventive Example 4 0.8 0.7 0.6 0.9 One 0.4 0.2 0.6 0.3 0.7 0.62 0.26 248.5 118.2 Inventive Example 5 0.9 0.6 0.4 0.7 0.9 1.1 0.8 0.7 0.9 0.9 0.79 0.20 238.1 99.8 Inventive Example 6 0.9 1.2 0.7 0.6 0.2 1.1 0.7 0.5 0.8 0.4 0.71 0.31 240.6 112.2 Inventive Example 7 0.7 0.5 0.3 0.4 0.5 0.4 0.5 0.4 0.2 0.8 0.47 0.18 251.2 102.4 Inventive Example 8 0.4 0.6 0.2 0.8 0.3 0.5 0.7 0.3 0.4 0.8 0.5 0.22 253.7 112.2 Inventive Example 9 0.3 0.2 0.4 0.3 0.4 0.5 0.6 0.7 0.5 0.7 0.46 0.17 243.4 109.2 Inventive Example 10 0.5 0.7 0.6 One 0.8 0.9 0.4 0.8 0.4 0.6 0.67 0.21 258.4 113.4

The results of observing Inventive Example 5 after the abrasion test under the conditions of Table 1 above are shown in FIG. 7, and the results of component analysis of the parts indicated in the drawings by the scanning electron microscope (EDS) are shown in Table 7. 4 is shown. The content of each element in the table is expressed in weight percent.

division O Cr Mn Fe Cu S1 1.82 15.72 4.43 78.67 15.19 S2 0 15.28 4.15 79.78 8.09 S3 0 16.61 4.09 84.19 10.94 S4 16.46 14.87 6.69 72.45 15.16 S5 3.62 5.90 5.46 31.51 74.56 S6 23.26 6.38 10.21 42.23 34.85 S7 20.54 8.22 12.43 41.98 29.39 S8 20.55 4.64 7.14 45.30 35.67 S9 18.80 5.58 10.18 30.14 47.73 S10 3.83 13.13 4.61 70.93 24.41

As can be seen in Table 1, the parts of the wear surface of the invention example 4 provided according to the conditions of the present invention all contained a large amount of the Cu component and the Fe component. In the wear crumb formed in the environment in which the bearing alloy or the bearing of the present invention is used, Cu and Fe which existed in the matrix due to smearing are present as main constituents, and these are oxidized to improve lubrication performance. It can be seen as proof. In particular, a component such as CuO in the oxide layer may be used as a lubricant, and the surface layer of the bearing may exhibit sufficient lubrication performance even in the non-lubricating condition when it is shown that a large amount of Cu is contained.

In addition, in order to confirm the difference between the case of the present invention and the case of not, the wear test was carried out for Comparative Example 1 and Example 4, and the wear debris generated according to the X-ray diffraction analysis (XRD) ) Test. The results are shown in FIG. In the figure, (a) shows comparative example 1 and (b) shows invention example 4. As can be seen in the drawing, the wear debris collected from the bearing manufactured by Comparative Example 1 had only a Fe (Ferrite) phase, but in the wear debris of Inventive Example 4 provided under the conditions of the present invention, it was not Fe phase but Cu2O, CuO. It was confirmed that various oxide phases such as Fe 3 O 4 and Fe 2 O 3 were observed. As described above, these phases can all improve the wear performance of the bearing by performing lubrication upon wear.

In addition, the results of observing the surface of the invention example 4 by wear time in order to observe the process of changing the surface of the bearing for each wear process is shown in FIG. Here, the load conditions were the same as the conditions of 1 ksi of Table 1. As shown in the figure, the surface (a) of the bearing, which was not worn at all, had a form in which the Cu precipitated phase existed in the matrix. Thereafter, after the wear progressed for about 300 seconds (b), the Cu precipitated phase and the matrix were worn to confirm that some wear debris was formed. Thereafter, as the wear progressed (c: 600 seconds, d: 1800 seconds), this phenomenon was accelerated more and more, but it was confirmed that the Cu precipitated phase was present on the surface in a sufficient ratio without being completely removed from the surface. As described above, it was determined that the Cu precipitated phase was pushed to the surface by the smearing phenomenon.

Thus, the advantageous effects of the present invention could be confirmed.

1 is a micrograph observing that the Cu precipitated phase is formed on the base metal,

2 is a schematic diagram illustrating a process in which so-called smearing occurs;

Figure 3 shows the relationship between Mn and C component to obtain a more advantageous effect of the present invention

Graph,

Figure 4 shows the component relationship between Cu and Cr to obtain a more advantageous effect of the present invention

Graph,

Figure 5 is a bearing manufactured by the invention example 4 and the prior art meeting the composition conditions of the present invention

Wear surface photos, after abrasion testing on

6 is a brown rice observed the surface of the Inventive Example 4 subjected to abrasion test with a scanning electron microscope

Sloping,

7 is an invention example after the wear test under the conditions of Table 1 in the embodiment of the present invention

5 was observed with a scanning electron microscope.

8 is an X-ray of the wear debris generated after the wear test of Comparative Example 1 and Example 4

Diffraction test results, and

9 is a result of observing the surface of the invention example 4 for each wear time.

Claims (6)

Cu containing 12-17% by weight, C: 0.35-0.6% by weight, Mn: over 0-8% by weight, Cr: 10-15% by weight, Sn: 0.5-2% by weight, porcelain containing the remaining Fe and unavoidable impurities Fe alloy for lubricated bearings. The Fe alloy for self-lubricating bearing according to claim 1, which satisfies the relationship of Mn + 10C: 6-11 wt% and Cu + 0.6Cr: 23 wt% or less. A method for producing a bearing alloy, the method for producing a self-lubricating bearing Fe alloy comprising casting a molten metal satisfying the compositional conditions of claim 2. A bearing that satisfies the compositional conditions of claim 2, wherein a Cu precipitated phase exists inside, and a ratio (a / b) of the hardness (a) of the Fe-based metal measured by a micro-Vickers hardness tester to the hardness (b) of the Cu precipitated phase is 2 Self-lubricating bearing of ~ 2.5. The self-lubricating bearing according to claim 4, wherein the austenite ratio measured by the Fe-based metal Ferritscope (MP-30E) is 99 vol% or more. delete

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