Method for detecting grinding burn on surface of BG801 steel bearing ring based on X-ray
By locating and marking the grinding burn area using acid etching, combined with X-ray residual austenite content detection, the problem of false scrapping of BG801 steel bearing rings due to grinding burn in the existing technology has been solved, realizing non-destructive testing and improving the yield rate.
Patent Information
- Application Number
- CN202511797933.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technology cannot effectively determine whether the grinding burn layer on the BG801 steel bearing ring has been removed during subsequent finishing, leading to false scrapping and economic losses.
The grinding burn area was located by acid etching and marked with laser. Combined with X-ray residual austenite content detection, it was determined whether the grinding burn layer was completely removed during finishing.
By using non-destructive testing methods, false rejections were reduced, the yield of BG801 steel bearing rings was improved, and economic losses were reduced.
Smart Images
Figure CN121595618A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nondestructive testing technology for materials, specifically relating to a method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays. Background Technology
[0002] Bearing rings undergo multiple processes during production, including forging, turning, heat treatment, and precision grinding. To prevent grinding burns on the bearing ring surface, acid etching is typically used to detect them. Grinding burns primarily occur because the instantaneous high temperature in the grinding zone triggers a phase transformation in the surface microstructure, leading to differences in surface hardness or residual stress compared to normal grinding. Grinding burns on the raceway surface of finished bearing rings significantly shorten bearing life, causing premature failure of the entire transmission system and posing a significant risk to the machine's operation. Therefore, grinding burns are a mandatory inspection item in the bearing ring grinding process. BG801 (15Cr14Co12Mo5Ni) steel, after carburizing heat treatment, contains a large amount of carbides on its surface, exhibiting higher hardness and wear resistance than existing second-generation bearing steels M50 and M50NiL, and is stainless steel. Therefore, the microstructure characteristics of grinding burns and the methods for detecting burns by acid corrosion in BG801 steel are different from those of other bearing steels.
[0003] Currently, the main method for detecting grinding burns is acid etching. Its advantages include low cost, simple operation, and no need for expensive testing equipment. However, its disadvantages include reliance on human visual judgment for color identification, and the subjective nature of the criteria, depending on the experience of professionals. Furthermore, since acid etching is followed by rough grinding, fine grinding, and ultra-fine grinding processes, some thin-area grinding burns can be removed in subsequent grinding processes. Because acid etching can only identify the size of the surface area of the grinding burn through color differences, it cannot determine whether the depth of the grinding burn can be removed in subsequent grinding processes. Therefore, workpieces with grinding burns that could be removed in subsequent grinding processes may be prematurely scrapped, resulting in significant economic losses. Therefore, it is necessary to find a non-destructive testing method for grinding burns.
[0004] Magnetoelasticity utilizes the noise signal (MP value) generated by the movement of magnetic domain walls in ferromagnetic materials under an alternating magnetic field. It also utilizes the principle that burns cause changes in tissue stress, resulting in abnormal MP values, to detect grinding burns. Its advantage is that it allows for non-destructive testing; however, its disadvantages include a high risk of false positives, as residual stress on the material surface and the geometry of bearing rings can interfere with the test results. Summary of the Invention
[0005] The purpose of this invention is to provide a method for detecting grinding burns on the surface of BG801 steel bearing rings using X-rays, in order to solve the problem that existing acid corrosion detection techniques for grinding burns on BG801 steel bearing rings cannot determine whether the grinding burn layer has been removed in subsequent finishing processes, resulting in premature scrapping of grinding burn workpieces that could be removed in subsequent finishing processes, leading to waste.
[0006] A method for detecting grinding burns on the surface of BG801 steel bearing rings using X-rays, comprising the following steps:
[0007] I. Grinding burn acid corrosion detection:
[0008] After acid etching, the BG801 steel bearing rings are visually inspected under an observation lamp to determine if there are grinding burns.
[0009] If the surface of the bearing ring is uniformly light gray or gray, it is a normal surface and is judged to be a qualified product for grinding burn detection, and can proceed to the subsequent finishing process.
[0010] If a dark gray or black tempering burn area or a bright white quenching burn area is observed on the surface of the bearing ring, and the observed grinding burn can be removed in the subsequent finishing process, then a laser mark is made on the end face next to the grinding burn area of the bearing ring, and the grinding burn area is photographed and recorded as bearing ring A, and then proceeds to the next process.
[0011] If dark gray or black tempering burn areas or bright white quenching burn areas are observed on the surface of the bearing rings, and the observed grinding burns cannot be removed in the subsequent finishing process, the bearing should be scrapped.
[0012] II. X-ray detection of residual austenite content:
[0013] The aforementioned bearing ring A proceeds to the next stage of the process. After rough grinding, fine grinding, and ultra-fine grinding, the residual austenite content in the original grinding burn area of bearing ring A is non-destructively tested using an X-ray residual austenite tester.
[0014] If the residual austenite content is less than 6%, it is determined that the original grinding burn of bearing ring A has been removed and it is judged as a qualified product without grinding burn.
[0015] If the residual austenite content is greater than or equal to 6%, it is determined that the original grinding burn of bearing ring A has not been completely removed and it should be scrapped.
[0016] Furthermore, the BG801 steel bearing rings after acid etching described in step one are prepared as follows:
[0017] S1 and BG801 steel bearing rings are degreased, de-oiled, and rinsed with deionized water.
[0018] S2. Immerse in an acid corrosion solution for acid corrosion for 60-100 seconds;
[0019] S3. Rinse with deionized water for 60-120 seconds.
[0020] S4. Neutralize with an alkaline solution for 20–40 seconds.
[0021] S5. Rinse with deionized water for 60-120 seconds.
[0022] S6. Use compressed air to dry the moisture on the surface of the BG801 steel bearing race.
[0023] Furthermore, the acid corrosion solution contains 10-20% nitric acid, 10-15% phosphoric acid, and 5-10 g / L ferric chloride hexahydrate, with the remainder being deionized water.
[0024] Furthermore, the alkaline solution is a sodium carbonate solution with a concentration of 45-50 g / L.
[0025] The advantages of this invention are:
[0026] The original method of detecting grinding burns using acid corrosion resulted in the bearing rings being scrapped upon detection of grinding burns, causing significant economic losses. This invention combines acid corrosion with X-ray residual austenite detection. The acid corrosion method locates and marks the grinding burn area. After subsequent roughing, finishing, and ultra-finishing, X-ray residual austenite detection is used to determine the residual austenite content at the marked grinding burn area. The residual austenite content determines whether the grinding burn layer has been removed. If the residual austenite content is less than 6%, the original grinding burn layer on the bearing ring is considered removed, and the bearing ring becomes a qualified product. Therefore, this invention can convert some products deemed unusable by the original acid corrosion method into qualified products, recovering some economic losses. Attached Figure Description
[0027] Figure 1 The image shown is of a bearing with grinding burns observed during acid corrosion testing of the BG801 steel bearing rings in the example.
[0028] Figure 2 The microstructure of the bearing ring with grinding burns detected by acid corrosion in the example is a metallographic image of the microstructure after radial wire cutting of the sample.
[0029] Figure 3 The X-ray diffraction pattern of the residual austenite content in the grinding burn zone of the bearing ring in the embodiment;
[0030] Figure 4The X-ray diffraction pattern of the residual austenite content in the bearing ring grinding burn area after subsequent rough grinding, fine grinding and ultra-fine grinding is shown in the example. Detailed Implementation
[0031] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.
[0032] Specific Implementation Method 1: This implementation method is a method for detecting grinding burns on the surface of BG801 steel bearing rings using X-rays, which is achieved through the following steps:
[0033] I. Grinding burn acid corrosion detection:
[0034] After acid etching, the BG801 steel bearing rings are visually inspected under an observation lamp to determine if there are grinding burns.
[0035] If the surface of the bearing ring is uniformly light gray or gray, it is a normal surface and is judged to be a qualified product for grinding burn detection, and can proceed to the subsequent finishing process.
[0036] If a dark gray or black tempering burn area or a bright white quenching burn area is observed on the surface of the bearing ring, and the observed grinding burn can be removed in the subsequent finishing process, then a laser mark is made on the end face next to the grinding burn area of the bearing ring, and the grinding burn area is photographed and recorded as bearing ring A, and then proceeds to the next process.
[0037] If dark gray or black tempering burn areas or bright white quenching burn areas are observed on the surface of the bearing rings, and the observed grinding burns cannot be removed in the subsequent finishing process, the bearing should be scrapped.
[0038] II. X-ray detection of residual austenite content:
[0039] The aforementioned bearing ring A proceeds to the next stage of the process. After rough grinding, fine grinding, and ultra-fine grinding, the residual austenite content in the original grinding burn area of bearing ring A is non-destructively tested using an X-ray residual austenite tester.
[0040] If the residual austenite content is less than 6%, it is determined that the original grinding burn of bearing ring A has been removed and it is judged as a qualified product without grinding burn.
[0041] If the residual austenite content is greater than or equal to 6%, it is determined that the original grinding burn of bearing ring A has not been completely removed and it should be scrapped.
[0042] The rough grinding, fine grinding, and ultra-fine grinding described in step two of this embodiment are all existing conventional techniques.
[0043] The X-ray residual austenite tester used in step two of this embodiment is a Stresstech D45 residual austenite analyzer, which can directly measure the surface of the bearing rings.
[0044] In step two of this embodiment, an X-ray residual austenite tester is used to perform non-destructive testing on the original grinding burn area of bearing ring A. The original grinding burn area is located by comparing the photographic records in step one.
[0045] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the BG801 steel bearing rings after acid etching in step one are prepared as follows:
[0046] S1 and BG801 steel bearing rings are degreased, de-oiled, and rinsed with deionized water.
[0047] S2. Immerse in an acid corrosion solution for acid corrosion for 60-100 seconds;
[0048] S3. Rinse with deionized water for 60-120 seconds.
[0049] S4. Neutralize with an alkaline solution for 20–40 seconds.
[0050] S5. Rinse with deionized water for 60-120 seconds.
[0051] S6. Use compressed air to dry the moisture on the surface of the BG801 steel bearing race. Everything else is the same as in Specific Implementation Method 1.
[0052] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the volume fraction of nitric acid in the acid corrosion solution is 10-20%, the volume fraction of phosphoric acid is 10-15%, the concentration of ferric chloride hexahydrate is 5-10 g / L, and the balance is deionized water. Everything else is the same as in Specific Implementation Method 2.
[0053] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Two in that the processing time in S2 is 70 seconds. Other steps and parameters are the same as in Specific Implementation Method Two.
[0054] Specific Implementation Method 5: This implementation method differs from Specific Implementation Method 2 in that the processing time in S2 is 80 seconds. Other steps and parameters are the same as in Specific Implementation Method 2.
[0055] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Two in that the processing time in S2 is 90 seconds. Other steps and parameters are the same as in Specific Implementation Method Two.
[0056] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Two in that the processing time in S3 is 100 seconds. Other steps and parameters are the same as in Specific Implementation Method Two.
[0057] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Two in that the alkaline solution is a sodium carbonate solution with a concentration of 45-50 g / L. Other steps and parameters are the same as in Specific Implementation Method Two.
[0058] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Two in that the processing time in S4 is 30 seconds. Other steps and parameters are the same as in Specific Implementation Method Two.
[0059] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Two in that the processing time in S5 is 110 seconds. Other steps and parameters are the same as in Specific Implementation Method Two.
[0060] The beneficial effects of the present invention are verified through the following embodiments:
[0061] The following description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
[0062] Example:
[0063] A method for detecting grinding burns on the surface of BG801 steel bearing rings using X-rays, comprising the following steps:
[0064] I. Grinding burn acid corrosion detection:
[0065] After acid etching, the BG801 steel bearing rings are visually inspected under an observation lamp to determine if there are grinding burns.
[0066] If the surface of the bearing ring is uniformly light gray or gray, it is a normal surface and is judged to be a qualified product for grinding burn detection, and can proceed to the subsequent finishing process.
[0067] If a dark gray or black tempering burn area or a bright white quenching burn area is observed on the surface of the bearing ring, and the observed grinding burn can be removed in the subsequent finishing process, then a laser mark is made on the end face next to the grinding burn area of the bearing ring, and the grinding burn area is photographed and recorded as bearing ring A, and then proceeds to the next process.
[0068] If dark gray or black tempering burn areas or bright white quenching burn areas are observed on the surface of the bearing rings, and the observed grinding burns cannot be removed in the subsequent finishing process, the bearing should be scrapped.
[0069] II. X-ray detection of residual austenite content:
[0070] The aforementioned bearing ring A proceeds to the next stage of the process. After rough grinding, fine grinding, and ultra-fine grinding, the residual austenite content in the original grinding burn area of bearing ring A is non-destructively tested using an X-ray residual austenite tester.
[0071] If the residual austenite content is less than 6%, it is determined that the original grinding burn of bearing ring A has been removed and it is judged as a qualified product without grinding burn.
[0072] If the residual austenite content is greater than or equal to 6%, it is determined that the original grinding burn of bearing ring A has not been completely removed and it should be scrapped.
[0073] The acid-etched BG801 steel bearing rings described in step one of this embodiment are prepared as follows:
[0074] S1 and BG801 steel bearing rings are degreased, de-oiled, and rinsed with deionized water.
[0075] S2. Immerse in an acid corrosion solution for acid corrosion for 80 seconds;
[0076] S3. Rinse with deionized water for 100 seconds.
[0077] S4. Neutralize with an alkaline solution for 30 seconds.
[0078] S5. Rinse with deionized water for 100 seconds;
[0079] S6. Use compressed air to dry the moisture on the surface of the BG801 steel bearing race.
[0080] The acid corrosion solution contains 15% nitric acid, 12% phosphoric acid, and 8 g / L ferric chloride hexahydrate, with the remainder being deionized water; the alkaline solution is a 50 g / L sodium carbonate solution.
[0081] Figure 1 The image shown is of a bearing with grinding burns detected by acid corrosion testing of the BG801 steel bearing rings in the example. It was determined that the grinding burn layer could be removed through subsequent finishing.
[0082] Figure 2 The image shown is a metallographic image of the microstructure of a bearing ring with grinding burns detected by acid corrosion, obtained after radial wire cutting. From... Figure 2The metallographic images show a thin layer of white quenching burn area on the surface of the bearing ring groove, with a thickness of about 8μm. The metallographic cross-section test results show that the prepared acid etching solution can effectively detect the quenching burn area of BG801 steel.
[0083] Tested using an X-ray diffractometer Figure 1 The residual austenite content in the grinding burn zone of the bearing ring is shown in the obtained X-ray diffraction pattern. Figure 3 As shown, according to the ASTM E975 standard for testing retained austenite in near-random oriented steel, the retained austenite content in the grinding burn zone is 44.1%, indicating that the retained austenite phase content in the grinding burn zone of BG801 steel increases.
[0084] After marking the grinding burn area on the bearing ring, and then performing rough grinding, fine grinding, and ultra-fine grinding, an X-ray residual austenite tester is used to test the residual austenite content at the marked grinding burn area. If the residual austenite content is less than 6%, it is considered that the original grinding burn layer of the bearing ring has been removed, and the bearing ring has become a qualified product without grinding burn.
[0085] Figure 4 After rough grinding, fine grinding, and ultra-fine grinding, the bearing rings with grinding burns were analyzed using X-ray diffraction to obtain the original grinding burn locations. According to the ASTM E975 standard for testing retained austenite in near-random oriented steel, the retained austenite content was 4.6%, proving that the original grinding burns were removed during the rough grinding, fine grinding, and ultra-fine grinding processes. The bearing rings with the original grinding burn layer have become qualified products without grinding burns after rough grinding, fine grinding, and ultra-fine grinding.
Claims
1. A method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays, characterized in that... It is implemented in the following steps: I. Grinding burn acid corrosion detection: After acid etching, the BG801 steel bearing rings are visually inspected under an observation lamp to determine if there are grinding burns. If the surface of the bearing ring is uniformly light gray or gray, it is a normal surface and is judged to be a qualified product without grinding burn, and can proceed to the subsequent finishing process. If a dark gray or black tempering burn area or a bright white quenching burn area is observed on the surface of the bearing ring, and the observed grinding burn can be removed in the subsequent finishing process, then a laser mark is made on the end face next to the grinding burn area of the bearing ring, and the grinding burn area is photographed and recorded as bearing ring A, and then proceeds to the next process. If dark gray or black tempering burn areas or bright white quenching burn areas are observed on the surface of the bearing rings, and the observed grinding burns cannot be removed in the subsequent finishing process, the bearing should be scrapped. II. X-ray detection of residual austenite content: The aforementioned bearing ring A proceeds to the next stage of the process. After rough grinding, fine grinding, and ultra-fine grinding, the residual austenite content in the original grinding burn area of bearing ring A is non-destructively tested using an X-ray residual austenite tester. If the residual austenite content is less than 6%, it is determined that the original grinding burn of bearing ring A has been removed and it is judged as a qualified product without grinding burn. If the residual austenite content is greater than or equal to 6%, it is determined that the original grinding burn of bearing ring A has not been completely removed and it should be scrapped.
2. The method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays according to claim 1, characterized in that... The BG801 steel bearing rings after acid etching described in step one are prepared as follows: S1 and BG801 steel bearing rings are degreased, de-oiled, and rinsed with deionized water. S2. Immerse in an acid corrosion solution for acid corrosion for 60-100 seconds; S3. Rinse with deionized water for 60-120 seconds. S4. Neutralize with an alkaline solution for 20–40 seconds. S5. Rinse with deionized water for 60-120 seconds. S6. Use compressed air to dry the moisture on the surface of the BG801 steel bearing race.
3. The method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays according to claim 2, characterized in that... The acid corrosion solution contains 10-20% nitric acid, 10-15% phosphoric acid, and 5-10 g / L ferric chloride hexahydrate, with the remainder being deionized water.
4. The method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays according to claim 2, characterized in that... The processing time in S2 is 70 seconds.
5. A method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays, as described in claim 2, characterized in that... The processing time in S2 is 80 seconds.
6. The method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays according to claim 2, characterized in that... The processing time in S2 is 90 seconds.
7. The method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays according to claim 2, characterized in that... The processing time in S3 is 100 seconds.
8. A method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays, as described in claim 2, characterized in that... The alkaline solution is a sodium carbonate solution with a concentration of 45-50 g / L.
9. A method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays, as described in claim 2, characterized in that... The processing time in S4 is 30 seconds.
10. A method for detecting grinding burns on the surface of BG801 steel bearing rings based on X-rays, as described in claim 2, characterized in that... The processing time in S5 is 110 seconds.