A method for analyzing and eliminating machining surface defects of babbitt alloy layer of bearing

Abstract

The present invention discloses a method for analyzing and eliminating machined surface defects of a babbitt alloy layer of a bearing, comprising the following steps: ① inferring that there are solid impurities in the babbitt alloy layer according to scratches formed on the surface of the babbitt alloy layer of the bearing when the babbitt alloy layer of the bearing is machined; ② collecting the machining cutting material of the babbitt alloy layer of the bearing for remelting to form recycled material; ③ analyzing the recycled material; ④ confirming the solid impurity components present in the recycled material; ⑤ filtering the recycled material for impurities through a filtering device; ⑥ analyzing the filtered recycled material; ⑦ determining the usage ratio of the filtered recycled material to the original material. The present invention provides a method for analyzing and eliminating machined surface defects of a babbitt alloy layer of a bearing, which effectively overcomes the scratch defects on the machined surface of the babbitt alloy layer of the bearing.

Description

Technical Field

[0001] The present invention relates to the technical field of babbitt alloys, and more specifically, to a method for analyzing and eliminating machining surface defects of a babbitt alloy layer of a bearing bush. Background Art

[0002] The bearing is usually processed with tin-based babbitt alloy (referred to as babbitt alloy) on the inner wall of the bearing to form a friction-reducing layer with a thickness of ≥13 mm. The friction-reducing layer retains a thickness of about 3.5 mm after cutting. During the processing, scratches appear on the surface of the friction-reducing layer. The scratch characteristics are as follows: (1) The direction of the scratch is consistent with the cutting direction of the processing; (2) The length of the scratch is generally less than the circumference of the inner surface of the bearing, and the number is about 1 to 5; (3) The visual scratch width is ≤ 0.2 mm; (4) The scratch is shallow and difficult to feel by hand, but is within the scale range that can be distinguished by vision; (5) The scratch has a very obvious starting point. Scratches seriously affect the appearance quality of the bearing and should be eliminated. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a method for analyzing and eliminating surface defects of the machining surface of the babbitt alloy layer of the bearing, so as to effectively overcome the scratch defects that appear on the machining surface of the babbitt alloy layer of the bearing.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: a method for analyzing and eliminating machining surface defects of a babbitt alloy layer of a bearing bush, comprising the following steps:

[0005] ① According to the scratches formed on the surface of the babbitt alloy layer of the bearing bush during machining, it is inferred that there are solid impurities in the babbitt alloy layer;

[0006] ② Collect the machining cuttings of the babbitt alloy layer of the bearing and remelt them to form recycled materials;

[0007] ③Analyze the recycled materials;

[0008] ④Confirm the solid impurities present in the recycled material;

[0009] ⑤ Filter impurities from the recycled material through a filtering device;

[0010] ⑥Analyze the recycled material after filtration;

[0011] ⑦ Determine the ratio of filtered recycled material to original material.

[0012] The present invention is further configured such that, in step ①, the scratch is an arc-shaped groove, and its arc line is on the tool cutting path.

[0013] The present invention is further configured such that in step ②, the cuttings of the babbitt alloy layer are put into a resistance furnace for remelting. After the cuttings are melted, the melt temperature is controlled at 380°C-390°C, and the melts at the upper, middle and lower parts of the furnace are taken to cast samples.

[0014] The present invention is further configured such that the analysis of the recycled material of the babbitt alloy layer of the bearing bush in step ③ includes the detection of the babbitt alloy composition and the metallographic sample detection.

[0015] The present invention is further configured such that after the regenerated material of the bearing bush Babbitt alloy layer is made into a metallographic sample, solid impurities are detected through a microscope.

[0016] The present invention is further configured to detect by scanning electron microscope and using backscattered electron imaging to detect that the solid impurities and the babbitt alloy are different substances.

[0017] The present invention is further configured such that the filtering device includes a housing, the housing includes cavity one and cavity two, a partition is installed on the housing, the partition separates cavity one and cavity two, a filter plate is installed on the partition, the housing is also installed with a base, the base is located in cavity two, the base is provided with a countersunk hole, a fixed block is installed at the bottom of the countersunk hole, a spiral portion two is provided on the outer wall of the fixed block, the fixed block is coaxial with the countersunk hole, and the inner diameter of the countersunk hole is larger than the maximum outer diameter of the spiral portion two.

[0018] The present invention is further configured such that a spiral portion 1 is provided on the inner wall of the countersunk hole, the countersunk hole can be inserted into a mounting ring, the inner diameter of the ring is the same as the maximum outer diameter of the spiral portion 2, and a spiral portion 3 is provided on the outer wall of the ring, and the spiral portion 3 can be screwed into the spiral portion 1.

[0019] The present invention is further configured such that a through hole 1 is connected to the bottom of the countersunk hole, a plug rod is installed in the through hole 1, the plug rod includes an extension rod located at the top, a disk body is installed on the top of the extension rod, the outer diameter of the disk body is larger than the through hole 1, the disk body is provided with a through hole 2, and the through hole 2 axially passes through the disk body.

[0020] In summary, the present invention has the following beneficial effects:

[0021] 1. The causes of scratches were determined by analyzing and tracing the source of scratches on the surface of the babbitt alloy layer of the bearing. The solid iron in the babbitt alloy matrix was effectively eliminated by filtering the remelted material of the babbitt alloy cutting, preventing the tool from adhering to solid iron and causing scratches on the surface during machining of the babbitt alloy layer of the bearing.

[0022] 2. By setting the ratio of recycled materials to virgin materials to 1:1, the iron content in the final processed material used for the babbitt alloy layer of the bearing meets the process requirements.

[0023] 3. Through the arrangement of spiral part 1 and spiral part 2, the iron impurities that sink to the bottom of the countersink will form resistance when flowing upward, so that the impurities gather in the countersink area, which is convenient for centralized cleaning and can also reduce the scouring of solid iron by the flowing melt, resulting in excessive melting of iron into the Babbitt alloy melt.

[0024] 4. When the plug rod is pulled downward to open the bottom of the through hole 1, and the matching ring rotates and moves downward, the Babbitt alloy liquid in the countersunk hole is discharged downward, while the Babbitt alloy melt in the cavity 2 above the countersunk hole continues to be in the filtering state. The filtering state does not need to be stopped. While improving the production efficiency, the solid iron in the cavity 2 is regularly cleared, thereby reducing the clogging of the filter plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a three-dimensional schematic diagram of a bearing bush body in an embodiment;

[0026] Figure 2 This is the metallographic specimen imaging diagram of the remelted material sample after cutting;

[0027] Figure 3 This is a backscattered electron imaging image of the remelted recycled material sample after cutting;

[0028] Figure 4 Energy spectrometer imaging of the remelted material sample after cutting;

[0029] Figure 5 is a three-dimensional diagram of the filtering device in the embodiment;

[0030] Figure 6 is a cross-sectional view of a filter device in an embodiment;

[0031] Figure 7 for Figure 6 The enlarged view of point A in the middle;

[0032] Figure 8 It is a partial stereoscopic diagram of the filtering device in the embodiment;

[0033] Fig. 9 It is a partial cross-sectional view of the filtering device in the embodiment.

[0034] Figure markings: box body 1, discharge pipe 11, cavity one 12, cavity two 13, partition 2, filter plate 3, base 4, countersunk hole 41, spiral part one 411, through hole one 42, plug rod 5, extension rod 51, disk body 52, through hole two 521, fixing block 6, spiral part two 61, cover plate 7, hopper 71, barrel 8, collar 9, spiral part three 91, cover 92, bearing body 100, scratched part 101. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1-Figure 9 As shown, this embodiment discloses a method for analyzing and eliminating machining surface defects of a bearing bushing babbitt alloy layer, comprising the following steps:

[0037] ① Such as Figure 1 As shown, the inner wall of the bearing body 100 is processed with a babbitt alloy layer, i.e., a friction-reducing layer, which mainly plays a friction-reducing role. The scratches formed by the tool machining the babbitt alloy layer are arc-shaped grooves. The scratches are the scratched portions 101 on the babbitt alloy layer on the inner wall of the bearing body 100. The arc line is on the tool cutting path, so it is inferred that the babbitt alloy layer contains large solid impurities. When the tool encounters the solid impurities during cutting, due to the high strength of the solid impurities, they are not immediately broken, but adhere to the cutting edge of the tool, and the babbitt alloy layer is cut along with the tool. And as the cutting process proceeds, under the action of the cutting force, the thickness of the solid inclusions adhered to the cutting edge gradually becomes thinner, and are eventually cut off by the cutting edge, or squeezed into the friction-reducing layer, or fall off together with the cutting material, and the tool returns to the normal working state, and intermittent scratched portions 101 are formed on the surface of the babbitt alloy layer.

[0038] Since the cutting amount of the Babbitt alloy layer on the inner wall of the bearing body 100 exceeds 60%, and Babbitt alloy is a high-value metal material, in order to improve the utilization rate of Babbitt alloy, the waste after cutting the Babbitt alloy layer is generally remelted and reused. It is inferred that solid impurities are mixed in during the remelting process.

[0039] ② Collect the machining cuttings of the babbitt alloy layer of the bearing bush for remelting to form recycled materials. Specifically, the cuttings of the babbitt alloy layer are put into a resistance furnace for remelting. After the cuttings are melted, the melt temperature is controlled at 380℃-390℃, and the melts in the upper, middle and lower parts of the furnace are taken to cast samples.

[0040] ③ Analyze the recycled materials, including Babbitt alloy composition detection and metallographic sample inspection. The Babbitt alloy composition detection is carried out according to the Babbitt alloy composition detection method, including atomic absorption spectroscopy, spark direct reading spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP-OES), X-ray fluorescence spectroscopy, etc. The results are compared with the GB / T8740 standard requirements and the Babbitt alloy data prepared with pure metals to form Table 1. According to the data in Table 1, the iron content of the recycled material is 0.067% higher than that of the original material, and is close to the upper limit specified in GB / T8740. After multiple tests, the iron content of the recycled material is 0.06%-0.08% higher than that of the original material, thus determining that the friction reduction layer that produces scratches uses recycled materials that have been remelted with iron debris.

[0041] Table 1

[0042]

[0043] like Figure 2 As shown in the figure, after the recycled material of the bearing babbitt alloy layer was made into a metallographic sample, solid impurities with a size of 70μm×200μm-150μm×280μm were detected through a microscope ( Figure 2 The center is circled). Figure 3 As shown, the solid impurities were detected by scanning electron microscope and backscattered electron imaging. The solid impurities were significantly different from the matrix, and the solid impurities were different substances from the Babbitt alloy matrix. Figure 3 The material composition of the midpoints [1], [2], [3], and [4] regions, such as Figure 4 As shown in the figure, red represents iron, blue represents tin, and green represents copper. Therefore, it is believed that the solid debris is iron chips that fall off during the processing of the steel shell of the bearing shell, mixed into the babbitt alloy chips, and brought into the recycled material during the remelting of the chips, and further brought into the babbitt alloy layer of the bearing shell. These iron chips are mixed in the babbitt alloy layer in solid form. At the same time, the solid debris does not contain tungsten, which eliminates the possibility that it comes from the cutting tool.

[0044] ④ The density of iron is 7.8g / cm³, and its melting point is 1538℃. The density of Babbitt alloy is 7.19~7.21g / cm³ (the density of liquid Babbitt alloy that becomes a melt is about 92% of its solid state), and its melting point is 223~371℃. When Babbitt alloy melts, iron still exists in solid form, thus confirming that the solid impurity component in the recycled material is iron.

[0045] Although the melting point of babbitt alloy is lower than that of iron, there are still signs that iron fragments melt into the melt when the chips are remelted, resulting in an increase in the iron content of the melt. This part of the iron element melts together with the babbitt alloy, which is different from the solid impurities included in the babbitt alloy.

[0046] ⑤ If Figure 5-Figure 9 As shown, the solid iron impurities in the recycled material are filtered through a filtering device to eliminate the solid iron impurities mixed in the recycled material cut by the Babbitt alloy layer.

[0047] like Figure 5 , Figure 6 As shown, the filtering device includes a box body 1, which is made of corundum material and has good heat preservation, heat resistance and anti-scouring properties. The box body 1 includes a cavity 12 and a cavity 2 13. The box body 1 is equipped with a partition 2, which separates the cavity 12 and the cavity 2 13. The partition 2 is equipped with a filter plate 3, and the filter plate 3 is inserted into the partition 2 for installation. The box body 1 also includes a discharge pipe 11, which is located at the bottom of the cavity 1 12. The molten babbitt alloy in the cavity 2 13 is filtered by the filter plate 3, enters the cavity 1 12, and slowly flows out from the discharge pipe 11 for ingot casting, so as to be melted again. A valve is also provided at the discharge pipe 11 to adjust the flow rate (not shown in the figure).

[0048] A cover plate 7 is installed above the second cavity 13 , and a hopper 71 is connected to the cover plate 7 . The Babbitt alloy melt in the barrel 8 is poured into the hopper 71 and flows into the second cavity 13 .

[0049] like Figure 8 As shown, the box 1 is also equipped with a base 4, and the wall of the base 4 is equipped with a heating wire for heat preservation to control the filtering temperature. The base 4 is located in the second cavity 13, and the base 4 is inserted into the bottom of the second cavity 13. Figure 6 , Figure 7 A countersunk hole 41 and a through hole 42 are provided at the bottom of the base 4. The through hole 42 is located below the countersunk hole 41, and the countersunk hole 41 is connected to the through hole 42. Figure 7 In the embodiment, the inner wall of the counterbore 41 is provided with a spiral portion 1 411, which is a spiral groove sunken along the inner wall of the counterbore 41. A fixed block 6 is installed at the bottom of the box body 1, and the main body of the fixed block 6 is located in the counterbore 41. A support foot is provided at the bottom of the fixed block 6, and the support foot is inserted into the box body 1 for fixing. The outer wall of the fixed block 6 is provided with a spiral portion 2 61, which is a spiral strip protruding along the outer wall of the fixed block 6. The fixed block 6 is coaxial with the counterbore 41, and the inner diameter of the counterbore 41 is larger than the maximum outer diameter of the spiral portion 2 61. As the iron impurities slowly settle to the bottom of the base 4 during the filtering process of the babbitt alloy, some of the impurities sink into the counterbore 41. During the flow of the babbitt alloy liquid, the impurities sunk into the counterbore 41 may still float up. Through the arrangement of the spiral portion 1 411 and the spiral portion 2 61, the solid iron impurities sunk into the bottom of the counterbore 41 will form resistance to the upward flow, and the solid iron impurities will gather in the area of ​​the counterbore 41, which is convenient for centralized cleaning.

[0050] like Fig. 9As shown, the countersunk hole 41 can be inserted with the mounting collar 9, and a collar cover 92 is installed on the top of the collar 9. Before the collar 9 is inserted into the countersunk hole 41, the cover plate 7 needs to be opened. The collar 9 is a cylindrical structure, and the inner diameter of the collar 9 is the same as the maximum outer diameter of the spiral portion 2 61. The outer wall of the collar 9 is provided with a spiral portion 3 91, and the spiral portion 3 91 can be screwed into the spiral portion 1 411, so that after the spiral portion 3 91 is screwed into the spiral portion 1 411, the collar 9 separates the countersunk hole 41 from the cavity 2 13, which is convenient for the subsequent rapid processing of the solid iron impurities accumulated in the countersunk hole 41.

[0051] like Figure 7 As shown, a plug rod 5 is installed on the through hole 1 42, and the plug rod 5 includes an extension rod 51 located at the top, and a disc 52 is installed on the top of the extension rod 51. The outer diameter of the disc 52 is larger than that of the through hole 1 42. The disc 52 is provided with a through hole 2 521, and the through hole 2 521 axially penetrates the disc 52. When the plug rod 5 is pulled downward to open the bottom of the through hole 1 42, and the matching ring 9 rotates and moves downward, the babbitt alloy liquid with solid iron impurities gathered in the counterbore 41 is discharged, and the babbitt alloy liquid in the cavity 2 13 above the counterbore 41 continues to be in a filtering state, and the filtering state does not need to be stopped. While improving the production efficiency, the solid iron impurities in the cavity 2 13 are regularly cleared, thereby reducing the clogging of the filter plate 3.

[0052] Since the density of the liquid Babbitt alloy that has become a melt is about 92% of its solid form, there is a certain difference between the solid density of the solid iron impurities and the density of the liquid Babbitt alloy, which makes it easier for the solid iron impurities to precipitate downward in the Babbitt alloy melt.

[0053] ⑥ The recycled material after filtration was analyzed, and samples were taken and tested for composition. As shown in Table 2, the iron content was 0.051%. After the babbitt alloy layer was processed on the inner wall of the bearing body 100 using the remelted recycled material, the iron content in the babbitt alloy layer (i.e., the friction reduction layer) was 0.081%. It is therefore speculated that the iron elements in the iron parts were melted into the babbitt alloy matrix during the entire process. These iron elements are melted into the babbitt alloy matrix instead of existing in the form of solid impurities. Therefore, they cannot be removed by filtration. The only way to minimize the contact between the recycled materials and the iron parts during the entire process is to minimize the contact between the recycled materials and the iron parts.

[0054] Table 2

[0055]

[0056] It is inferred that in step ⑤, the filter device is provided with components such as sink hole 41, fixing block 6, collar 9, etc. to discharge iron impurities regularly, which helps to reduce the iron content. As shown in Table 3, the iron content in the regenerated filter material with an interval of 1 hour for iron impurity discharge is compared with that in the regenerated filter material with an interval of 4 hours for iron impurity discharge. The iron content in the regenerated filter material with an interval of 4 hours for iron impurity discharge is 0.053%, which is greater than the iron content of 0.047% in the regenerated filter material with an interval of 1 hour for iron impurity discharge.

[0057] Therefore, the regular discharge of iron impurities can reduce the iron impurities that the recycled material melt contacts during the filtering process, so as to avoid more iron elements melting into the recycled material Babbitt alloy melt in the form of non-impurities.

[0058] Table 3

[0059]

[0060] ⑦ Determine the ratio of filtered recycled material to virgin material to be 1:1, so that the iron content of the babbitt alloy anti-friction layer made from the final processed material of the 100 babbitt alloy layer of the bearing body meets the requirement of less than 0.08%.

[0061] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for analyzing and eliminating machining surface defects of a bearing bushing Babbitt alloy layer, characterized in that: The steps include: ① According to the scratches formed on the surface of the babbitt alloy layer of the bearing bush during machining, it is inferred that there are solid impurities in the babbitt alloy layer. When the tool encounters the solid impurities during cutting, the solid impurities adhere to the cutting edge of the tool and cut the babbitt alloy layer together with the tool. As the cutting process proceeds, under the action of the cutting force, the thickness of the solid adhered to the cutting edge gradually becomes thinner, and is eventually cut off by the cutting edge, or squeezed into the anti-friction layer, or falls off together with the cutting material. The tool returns to normal working state, and the intermittent scratches are formed on the surface of the babbitt alloy layer; ② Collect the machining cuttings of the bearing bush babbitt alloy layer for remelting to form recycled materials. When the cuttings are remelted, iron debris melts into the melt, which increases the iron content of the remelted melt. ③Analyze the recycled materials; ④Confirm the solid impurities present in the recycled material; ⑤ Filter impurities from the recycled material through a filtering device; ⑥Analyze the recycled material after filtration; ⑦ Determine the ratio of recycled materials and original materials after filtration; The filtering device comprises a housing (1), the housing (1) comprising a cavity 1 (12) and a cavity 2 (13), the housing (1) being provided with a partition (2), the partition (2) separating the cavity 1 (12) and the cavity 2 (13), the partition (2) being provided with a filter plate (3), the housing (1) being further provided with a base (4), the base (4) being located in the cavity 2 (13), the base (4) being provided with a counterbore (41), a fixing block (6) being provided at the bottom of the counterbore (41), the outer wall of the fixing block (6) being provided with a second spiral portion (61), the fixing block (6) being coaxial with the counterbore (41), the inner diameter of the counterbore (41) being larger than the maximum outer diameter of the second spiral portion (61), and the inner wall of the counterbore (41) being provided with a first spiral portion (411); The counterbore (41) can be inserted into a mounting collar (9), the inner diameter of the collar (9) being the same as the maximum outer diameter of the second spiral portion (61), the outer wall of the collar (9) being provided with a third spiral portion (91), the third spiral portion (91) being capable of being screwed into the first spiral portion (411), after the third spiral portion (91) is screwed into the first spiral portion (411), the collar (9) separates the counterbore (41) from the second cavity (13); The bottom of the counterbore (41) is connected to a through hole 1 (42), a plug rod (5) is installed in the through hole 1 (42), the plug rod (5) includes an extension rod (51) located at the top, a disk body (52) is installed on the top of the extension rod (51), the outer diameter of the disk body (52) is larger than the through hole 1 (42), the disk body (52) is provided with a through hole 2 (521), and the through hole 2 (521) axially penetrates the disk body (52).

2. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 1 is characterized in that: In step ①, the scratch is an arc-shaped groove, and its arc line is on the tool cutting path.

3. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 1 is characterized in that: In step ②, the cuttings of the babbitt alloy layer are put into a resistance furnace for remelting. After the cuttings are melted, the melt temperature is controlled at 380°C-390°C, and the melts at the upper, middle and lower parts of the furnace are taken to cast samples.

4. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 1 is characterized in that: The analysis of the recycled material of the babbitt alloy layer of the bearing in step ③ includes the detection of the babbitt alloy composition and the metallographic sample inspection.

5. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 4 is characterized in that: After the recycled material of the bearing babbitt alloy layer is made into a metallographic sample, the solid impurities are detected under a microscope.

6. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 5 is characterized in that: Scanning electron microscopy and backscattered electron imaging revealed that the solid impurities were different from the babbitt alloy.

7. The method for analyzing and eliminating machining surface defects of a bearing bush babbitt alloy layer according to claim 1 is characterized in that: The counterbore (41) can be inserted into a mounting collar (9), the inner diameter of the collar (9) being the same as the maximum outer diameter of the second spiral portion (61), the outer wall of the collar (9) being provided with a third spiral portion (91), and the third spiral portion (91) being able to be screwed into the first spiral portion (411).

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