Heat treatment process method for self-aligning roller bearing ring

Abstract

The invention discloses a heat treatment process method for a self-aligning roller bearing ring, and belongs to the field of heat treatment processing of self-aligning roller bearing parts. And 2, quenching and heating the ferrule on a roller hearth furnace salt bath martensite quenching production line with a protective atmosphere, and inspecting after salt bath cooling, air cooling, cleaning and rust prevention and salt bath tempering treatment. In the effective wall thickness range of 18-25 mm, the GCr15SiMn high-carbon chromium bearing steel with better hardenability is selected to replace GCr15; and when the sleeve ring is placed, the soft point defect of the contact part of the sleeve ring in the quenching process can be prevented, and the processing yield is improved. Contact type salt bath tempering is adopted, so that the structure is sufficiently transformed, and tempering is sufficient; and the tempering temperature of 200-250 DEG C is adopted, it is guaranteed that the impact toughness of the ferrule is improved by 10%-15% compared with an original technological method, the content of retained austenite in the ferrule after heat treatment is reduced to be within 5%, and it is guaranteed that the dimensional stability of the ferrule is high during subsequent machining and later use.

Description

Technical Field

[0001] The invention belongs to the field of heat treatment processing of parts of spherical roller bearings, and particularly relates to a heat treatment process method for spherical roller bearing rings. Background Art

[0002] Spherical roller bearings are suitable for bearing radial loads and axial loads acting in both directions, and are particularly suitable for working environments with heavy loads or vibration loads. The bearing rings not only need to have high hardness, but also good toughness. Such bearings are mainly used in industries such as paper machinery, railway vehicle axles, rolling mill rolls, crushers, vibrating screens, printing machinery, woodworking machinery, and various industrial speed reducers.

[0003] Among them, spherical roller bearings with an outer diameter of the bearing ring ≤ 500 mm and an effective wall thickness less than 25 mm are widely used. The most commonly used bearing ring is GCr15 high-carbon chromium bearing steel. The main chemical components of GCr15 are by mass percentage: C: 0.95% - 1.05%, Si: 0.15 - 0.35, Mn: 0.25% - 0.45%, Cr: 1.40% - 1.65%, Mo ≤ 0.10%, Ni ≤ 0.25%, Cu ≤ 0.25%, and the balance Fe.

[0004] For rings made of GCr15 with an effective wall thickness of 18 - 25 mm, with the current heat treatment technology, the metallographic structure and hardness of the quenched and tempered rings are detected. The detection is based on "GB / T 34891-2017 Technical Conditions for Heat Treatment of High-Carbon Chromium Bearing Steel Parts for Rolling Bearings". The metallographic structure and hardness within 3 mm meet the standard requirements, while those outside 3 mm do not meet the standard requirements, and the retained austenite of the bearing ring is unqualified.

[0005] The troostite structure, hardness, and retained austenite at the core of the bearing ring are unqualified, which affect the dimensional accuracy of the bearing and the contact fatigue life of the bearing, thereby causing the bearing to fail prematurely and resulting in certain economic losses. Summary of the Invention

[0006] The purpose of the invention is to solve the above-mentioned existing technical problems, and provide a heat treatment process method for spherical roller bearing rings.

[0007] A heat treatment process method for spherical roller bearing rings is realized according to the following steps:

[0008] I. Ring placement, loading, and pre - cleaning: Place the turned GCr15SiMn high - carbon chromium bearing steel rings in a heat - resistant steel tooling, arranging 2 - 3 layers. Use wire mesh pads to separate each layer. The length and width of the wire mesh pads are 50 mm smaller than those of the heat - resistant steel tooling. Leave gaps between the rings in each layer. Use wire mesh pads to separate the rings in the top layer. The height of the wire mesh pad is 5 - 10 mm smaller than that of the rings, and the diameter of the wire mesh pad is 5 - 10 mm smaller than that of the rings. After completing the ring placement and loading, conduct pre - cleaning to obtain the pre - cleaned rings.

[0009] II. Quenching and heating of the above - mentioned pre - cleaned rings are carried out on a roller - hearth furnace salt - bath martensite quenching production line with a protective atmosphere, followed by salt - bath cooling, air cooling, and cleaning and rust prevention in sequence, then salt - bath tempering treatment, and finally inspection. After the test results meet the standards, the heat treatment process of the spherical roller bearing rings is completed.

[0010] Furthermore, the chemical composition of the GCr15SiMn high - carbon chromium bearing steel rings in step I is as follows: by mass percentage, C: 0.95% - 1.05%, Si: 0.45% - 0.75%, Mn: 0.95% - 1.25%, Cr: 1.40% - 1.65%, Mo ≤ 0.10%, Ni ≤ 0.25%, Cu ≤ 0.25%, and the balance is Fe.

[0011] Furthermore, the effective wall thickness of the GCr15SiMn high - carbon chromium bearing steel rings in step I is 18 - 25 mm.

[0012] Furthermore, the material of the wire mesh pad in step I is the same as that of the heat - resistant steel tooling, both being Cr25Ni^20. The wire mesh pad is made of heat - resistant steel wires with a diameter of 2.5 - 3.5 mm, and the small mesh size of the wire mesh pad is 25 - 35 mm.

[0013] Furthermore, the pre - cleaning in step I: The pre - cleaning station is divided into cleaning with a cleaning agent and cleaning with clean water. The cleaning temperature is 50 - 80°C for each, and the cleaning time for each step is 8 - 10 min. After cleaning, dry at 100 - 150°C for 8 - 10 min.

[0014] Furthermore, the protective atmosphere in step II: The volume ratio of nitrogen + methanol drip + propane is 48:2:1, the furnace pressure is 150 - 220 Pa, and the carbon potential CP% in the furnace is 0.65% - 0.9%.

[0015] Furthermore, the quenching and heating in step II: The heating temperature is 830 - 835°C, and the heating time is 80 - 100 min.

[0016] Further, in step two, the salt bath cooling and air cooling are as follows: for the salt bath cooling, the salt temperature is 160 - 190°C, the water content in the salt bath is 0.6% - 0.8%, the rotation speed of the salt bath stirring motor is 600 - 1200 rpm, the up and down moving speed of the salt bath is 200 - 500 mm / s, and the cooling time is 8 - 10 min; for the air cooling, there are 3 workstations in total, the air cooling time for each workstation is 8 - 10 min, and the surface temperature of the ring after air cooling is ≤50°C.

[0017] Further, in step two, the cleaning and rust prevention are as follows: Immersion cleaning and rust prevention are adopted, with a total of three workstations:

[0018] ①. Ultrasonic cleaning, with a frequency of 28 - 30 KHZ and a water temperature of 40 - 60°C;

[0019] ②. Foaming cleaning, with a water temperature of 40 - 60°C;

[0020] ③. Rust prevention cleaning, at room temperature, rust prevention cleaning is carried out with an aqueous solution containing sodium nitrite with a concentration of 0.5% - 0.8%, and then dried at 100 - 120°C for 5 - 10 min.

[0021] Further, in step two, the salt bath tempering treatment is as follows: The tempering medium is nitrate salt, the tempering temperature is 200 - 250°C, and the tempering time is 240 - 300 min; the nitrate salt is a mixture of potassium nitrate and sodium nitrite in a mass ratio of 1:1.

[0022] Further, the qualified standards for the inspection in step two are as follows:

[0023] For the martensite structure within 3 mm: 2 - 4 grades; the troostite structure is less than 1 grade; hardness: 59 - 64 HRC;

[0024] For the martensite structure outside 3 mm: 2 - 4 grades; the troostite structure is less than 2 grades; hardness: 59 - 64 HRC;

[0025] The content of retained austenite is less than 5%.

[0026] Compared with the existing process, the present invention:

[0027] 1. Compared with the original process, within the range of effective wall thickness of 18 - 25 mm, GCr15SiMn high-carbon chromium bearing steel with better hardenability is selected to replace GCr15;

[0028] 2. Compared with the original process, in the placement method of the rings, heat-resistant steel mesh pads are used to separate between layers, which can prevent soft spot defects from occurring at the contact parts of the rings during the quenching process; the rings on the top layer are separated by mesh pads to prevent the rings from coming into contact with each other due to the rapid rotation of the rods when entering the first workstation in the furnace and when leaving the furnace, which may cause soft spot (the meaning of soft spot is insufficient hardness) defects at the contact parts during the quenching process.

[0029] 3. Compared with the original process, in terms of the placement method of the rings, the original process used a stacking method (for example, 4 rings in the first layer and only 2 rings in the second layer), while the current process uses a pressing method (for example, 4 rings in the first layer and also 4 rings in the second layer). By improving the placement method, the output during heat treatment processing has been increased.

[0030] 4. Compared with the original process, a salt bath tempering process is adopted. Due to the relatively large effective wall thickness and outer diameter of the rings, a contact tempering process method (the tempering medium is nitrate salt) is used, and the tissue transformation during quenching is sufficient, and the rings are fully tempered.

[0031] 5. Compared with the original process, a high-temperature tempering process is adopted, which can reduce the hardness of the quenched rings (surface hardness and core hardness) to the range of 59 - 61 HRC, ensuring that the impact toughness of the rings can be increased by 10% - 15% compared with the original process method.

[0032] 6. Compared with the original process, a tempering temperature of 200 - 250 °C is adopted during tempering, which can reduce the retained austenite content in the rings after heat treatment to less than 5% (the retained austenite content in the rings after heat treatment by the original process is 8% - 12%), ensuring high dimensional stability of the rings during subsequent processing and later use.

[0033] The present invention is applicable to the heat treatment of the rings of spherical roller bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a 1000 - fold micrograph of the microstructure of the inner ring of the GCr15SiMn high - carbon chromium spherical roller bearing 22328 after heat treatment in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0035] The technical solution of the present invention is not limited to the following specific embodiments listed, but also includes any combination between the specific embodiments.

[0036] Specific Embodiment 1: A heat treatment process method for the rings of spherical roller bearings in this embodiment is realized according to the following steps:

[0037] I. Ring placement, loading, and pre - cleaning: Place the turned GCr15SiMn high - carbon chromium bearing steel rings in a heat - resistant steel tooling, place 2 - 3 layers, separate each layer with a mesh pad. The length and width dimensions of the mesh pad are 50 mm smaller than the length and width of the heat - resistant steel tooling. Leave a gap between the rings placed in each layer. Use a mesh pad to separate the rings in the top layer. The height of the mesh pad is 5 - 10 mm smaller than the rings, and the diameter of the mesh pad is 5 - 10 mm smaller than the rings. After completing the ring placement and loading, perform pre - cleaning to obtain the pre - cleaned rings;

[0038] Second, the above-mentioned cleaned rings are quenched and heated on a roller hearth furnace salt bath martensite quenching production line with a protective atmosphere, then successively subjected to salt bath cooling, air cooling, cleaning and rust prevention, and then salt bath tempering treatment. Finally, inspection is carried out. After the test results meet the standards, the heat treatment process of the spherical roller bearing rings is completed.

[0039] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the chemical composition of the GCr15SiMn high-carbon chromium bearing steel rings in Step 1: by mass percentage, C: 0.95% - 1.05%, Si: 0.45% - 0.75%, Mn: 0.95% - 1.25%, Cr: 1.40% - 1.65%, Mo ≤ 0.10%, Ni ≤ 0.25%, Cu ≤ 0.25% and the balance of Fe. Other steps and parameters are the same as those in Specific Embodiment 1.

[0040] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 is that the effective wall thickness of the GCr15SiMn high-carbon chromium bearing steel rings in Step 1 is 18 - 25 mm. Other steps and parameters are the same as those in Specific Embodiment 1.

[0041] Specific Embodiment 4: The difference between this embodiment and Specific Embodiment 1 is that the material of the wire mesh pad in Step 1 is the same as that of the heat-resistant steel tooling, both are Cr25Ni20; the wire mesh pad is made of heat-resistant steel wire with a diameter of 2.5 - 3.5 mm, and the small mesh size of the wire mesh pad is 25 - 35 mm. Other steps and parameters are the same as those in Specific Embodiment 1.

[0042] Specific Embodiment 5: The difference between this embodiment and Specific Embodiment 1 is that the pre-cleaning in Step 1: at the pre-cleaning station, it is divided into cleaning agent cleaning and clean water cleaning; the cleaning temperature is 50 - 80 °C, and the cleaning time for each process is 8 - 10 min; after cleaning, it is dried at 100 - 150 °C for 8 - 10 min. Other steps and parameters are the same as those in Specific Embodiment 1.

[0043] The purpose of the pre-cleaning in this embodiment is to remove impurities such as cutting fluid, dust, and oil stains remaining on the surface of the rings, and ensure that the appearance colors of the rings after quenching and tempering are consistent.

[0044] Specific Embodiment 6: The difference between this embodiment and Specific Embodiment 1 is that the protective atmosphere in Step 2: the volume ratio of nitrogen + methanol drip + propane is 48:2:1, the furnace pressure is 150 - 220 Pa, and the carbon potential CP% in the furnace is 0.65% - 0.9%. Other steps and parameters are the same as those in Specific Embodiment 1.

[0045] In this embodiment, the methanol is immediately vaporized when dripped into the furnace; nitrogen, methanol, and propane enter the furnace through their respective channels.

[0046] Specific Embodiment Seven: The difference between this embodiment and Specific Embodiment One is that in step two, for the quenching heating, the heating temperature is 830 - 835 °C and the heating time is 80 - 100 min. Other steps and parameters are the same as those in Specific Embodiment One.

[0047] Specific Embodiment Eight: The difference between this embodiment and Specific Embodiment One is that in step two, for the salt bath cooling and air cooling, the salt temperature for salt bath cooling is 160 - 190 °C, the water content in the salt bath is 0.6% - 0.8%, the rotational speed of the salt bath stirring motor is 600 - 1200 rpm, the up - and - down moving speed of the salt bath is 200 - 500 mm / s, the cooling time is 8 - 10 min; there are 3 air - cooling stations in total, the air - cooling time for each station is 8 - 10 min, and the surface temperature of the ring after air cooling is ≤50 °C. Other steps and parameters are the same as those in Specific Embodiment One.

[0048] Specific Embodiment Nine: The difference between this embodiment and Specific Embodiment One is that in step two, for the cleaning and rust prevention, immersion - type cleaning and rust prevention are adopted, with a total of three stations:

[0049] ①. Ultrasonic cleaning, with a frequency of 28 - 30 KHZ and a water temperature of 40 - 60 °C;

[0050] ②. Foaming cleaning, with a water temperature of 40 - 60 °C;

[0051] ③. Rust - prevention cleaning, at room temperature, rust - prevention cleaning is carried out using an aqueous solution containing 0.5% - 0.8% sodium nitrite, and then dried at 100 - 120 °C for 5 - 10 min. Other steps and parameters are the same as those in Specific Embodiment One.

[0052] Specific Embodiment Ten: The difference between this embodiment and Specific Embodiment One is that in step two, for the salt bath tempering treatment, the tempering medium is nitrate salt, the tempering temperature is 200 - 250 °C, and the tempering time is 240 - 300 min; the nitrate salt is a mixture of potassium nitrate and sodium nitrite in a mass ratio of 1:1. Other steps and parameters are the same as those in Specific Embodiment One.

[0053] Specific Embodiment Eleven: The difference between this embodiment and Specific Embodiment One is that the qualified standards for the inspection in step two are as follows:

[0054] For martensite structure within 3 mm: 2 - 4 grades; troostite structure less than grade 1; hardness: 59 - 64 HRC;

[0055] For martensite structure outside 3 mm: 2 - 4 grades; troostite structure less than grade 2; hardness: 59 - 64 HRC;

[0056] The content of retained austenite is less than 5%. Other steps and parameters are the same as those in Specific Embodiment One.

[0057] The beneficial effects of the present invention are verified through the following embodiments:

[0058] Embodiment:

[0059] A heat treatment process method for a spherical roller bearing ring is realized according to the following steps:

[0060] I. Ring placement and loading and pre - cleaning: Place the turned GCr15SiMn high - carbon chromium bearing steel rings in a heat - resistant steel tooling, arranging them in 2 layers. Place 9 rings in the first layer and 9 rings in the second layer. Use a wire mesh pad to separate between each layer. The length and width of the wire mesh pad are 700×700mm. Leave a gap between the rings placed in each layer. Use a wire mesh pad to separate the rings in the top layer. The height of the wire mesh pad is 95mm (the height of the inner ring of 22328 is 102mm), and the length is 198mm (the outer diameter of the inner ring of 22328 is 200mm). After completing the ring placement and loading, conduct pre - cleaning to obtain the pre - cleaned rings;

[0061] II. Quench - heat the above - mentioned pre - cleaned rings on a 750 roller - hearth furnace salt - bath martensite quenching production line with a protective atmosphere, then conduct salt - bath cooling, air cooling, and cleaning and rust prevention in sequence, then conduct salt - bath tempering treatment, and finally conduct inspection. After the inspection results meet the standards, the heat treatment process of the spherical roller bearing ring is completed.

[0062] The chemical composition of the GCr15SiMn high - carbon chromium bearing steel rings described in step I of this embodiment: by mass percentage, C: 1.00%, Si: 0.70%, Mn: 1.00%, Cr: 1.60%, Mo≤0.10%, Ni≤0.25%, Cu≤0.25%, and the balance is Fe.

[0063] The GCr15SiMn high - carbon chromium bearing steel rings described in step I of this embodiment are the inner rings of spherical roller bearings 22328, and their effective wall thickness is 20.5mm.

[0064] The material of the wire mesh pad described in step I of this embodiment is the same as that of the heat - resistant steel tooling, both being Cr25Ni20; the wire mesh pad is made of heat - resistant steel wires with a diameter of 3mm, and the small mesh size of the wire mesh pad is 30mm.

[0065] The pre - cleaning described in step I of this embodiment: At the pre - cleaning station, it is divided into cleaning agent cleaning and clean - water cleaning; the cleaning temperature is 80°C for both, and the cleaning time for each process is 10min; after cleaning, dry at 130°C for 10min.

[0066] The purpose of the pre - cleaning in this embodiment is to remove impurities such as cutting fluid, dust, and oil stains remaining on the surface of the rings, and ensure that the appearance colors of the rings after quenching and tempering are consistent.

[0067] In step two of this embodiment, the protective atmosphere: the volume ratio of nitrogen + methanol drip + propane is 48:2:1, the furnace pressure is 200 Pa, and the carbon potential CP% in the furnace is 0.7%.

[0068] In step two of this embodiment, the quenching heating: the heating temperature is 830 - 835 °C, and the heating time is 100 min.

[0069] In step two of this embodiment, the salt bath cooling and air cooling: the salt temperature for salt bath cooling is 180 °C, the water content in the salt bath is 0.7%, the rotation speed of the salt bath stirring motor is 800 rpm, the up and down moving speed of the salt bath is 500 mm / s, and the cooling time is 10 min; there are 3 air cooling stations in total, the air cooling time for each station is 10 min, and the surface temperature of the race after air cooling ≤ 50 °C.

[0070] In step two of this embodiment, the cleaning and rust prevention: immersion cleaning and rust prevention are adopted, with a total of three stations:

[0071] ①. Ultrasonic cleaning, frequency 28KHZ, water temperature 50 °C;

[0072] ②. Foaming cleaning, water temperature 50 °C;

[0073] ③. Rust prevention cleaning, at room temperature, rust prevention cleaning is carried out with an aqueous solution containing 0.6% sodium nitrite, and then dried at 120 °C for 10 min.

[0074] In step two of this embodiment, the salt bath tempering treatment: the tempering medium is nitrate salt, the tempering temperature is 225 - 235 °C, and the tempering time is 270 min; the nitrate salt is a mixture of potassium nitrate and sodium nitrite in a mass ratio of 1:1.

[0075] The qualified standards for the inspection in step two of this embodiment are as follows:

[0076] Martensite structure within 3 mm: grade 3; troostite structure less than grade 1; hardness: 60 / 60 / 60 HRC;

[0077] Martensite structure outside 3 mm: grade 3; troostite structure less than grade 1; hardness: 59.5 / 59.5 / 60 HRC;

[0078] Content of retained austenite: 3%.

[0079] For the inner ring of the spherical roller bearing 22328 in this embodiment, the raw material adopts GCr15SiMn high-carbon chromium bearing steel with better hardenability. After heat treatment using the process in this embodiment, the test results meet the standard requirements; its microstructure after heat treatment is as Figure 1 shown, the troostite structure outside 3 mm of the race < grade 1; the difference between the core hardness and the surface hardness is less than 1 HRC; the surface hardness of the race is uniform and there are no soft spots; the content of retained austenite is low, and the dimensions of the race are stable.

[0080] The above are only the preferred embodiments of the present invention and are 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 recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat treatment process method for a spherical roller bearing ring, characterized in that It is realized according to the following steps: I. Ring placing, loading and pre - cleaning: Place the turned GCr15SiMn high - carbon chromium bearing steel rings in a heat - resistant steel tooling, arranging 2 - 3 layers. Use wire mesh pads to separate between each layer. The length and width dimensions of the wire mesh pads are 50 mm smaller than those of the heat - resistant steel tooling. Leave gaps between the rings placed in each layer. Use wire mesh pads to separate the rings in the top layer. The height of the wire mesh pad is 5 - 10 mm smaller than that of the rings, and the diameter of the wire mesh pad is 5 - 10 mm smaller than that of the rings. After completing the ring placing and loading, conduct pre - cleaning to obtain the pre - cleaned rings; II. Quench - heat the above - mentioned pre - cleaned rings on a roller - hearth furnace salt - bath martensite quenching production line with a protective atmosphere, then successively conduct salt - bath cooling, air - cooling and cleaning and rust - prevention, then conduct salt - bath tempering treatment, and finally conduct inspection. After the inspection results meet the standards, the heat treatment process of the spherical roller bearing rings is completed.

2. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The chemical composition of the GCr15SiMn high - carbon chromium bearing steel rings described in step I: By mass percentage, C: 0.95% - 1.05%, Si: 0.45% - 0.75%, Mn: 0.95% - 1.25%, Cr: 1.40% - 1.65%, Mo ≤ 0.10%, Ni ≤ 0.25%, Cu ≤ 0.25% and the balance is Fe.

3. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The effective wall thickness of the GCr15SiMn high - carbon chromium bearing steel rings described in step I is 18 - 25 mm.

4. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The material of the wire mesh pad described in step I is the same as that of the heat - resistant steel tooling, both are Cr25Ni20; the wire mesh pad is made of heat - resistant steel wires with a diameter of 2.5 - 3.5 mm, and the small mesh size of the wire mesh pad is 25 - 35 mm.

5. The heat treatment process method for a spherical roller bearing ring according to claim 1, characterized in that The pre - cleaning described in step I: At the pre - cleaning station, it is divided into cleaning agent cleaning and clean - water cleaning; the cleaning temperature is 50 - 80 °C for each, and the cleaning time for each process is 8 - 10 min; after cleaning, dry at 100 - 150 °C for 8 - 10 min.

6. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The protective atmosphere described in step II: The volume ratio of nitrogen + methanol drip + propane is 48:2:1, the furnace pressure is 150 - 220 Pa, and the carbon potential CP% in the furnace is 0.65% - 0.9%; the quench - heating described in step II: The heating temperature is 830 - 835 °C, and the heating time is 80 - 100 min.

7. The heat treatment process method for a spherical roller bearing ring according to claim 1, characterized in that The salt - bath cooling and air - cooling described in step II: The salt temperature for salt - bath cooling is 160 - 190 °C, the water content in the salt bath is 0.6% - 0.8%, the rotation speed of the salt - bath stirring motor is 600 - 1200 rpm, the up - and - down moving speed of the salt bath is 200 - 500 mm / s, and the cooling time is 8 - 10 min; there are 3 air - cooling stations in total, the air - cooling time for each station is 8 - 10 min, and the surface temperature of the rings after air - cooling ≤ 50 °C.

8. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The cleaning and rust - prevention described in step II: Adopt immersion - type cleaning and rust - prevention, with a total of three stations: ①. Ultrasonic cleaning, frequency 28 - 30 KHZ, water temperature 40 - 60 °C; ②. Foaming cleaning, water temperature 40 - 60 °C; ③. Rust - prevention cleaning, at room temperature, conduct rust - prevention cleaning with an aqueous solution containing 0.5% - 0.8% sodium nitrite, and then dry at 100 - 120 °C for 5 - 10 min.

9. The heat treatment process method of a spherical roller bearing ring according to claim 1, wherein The salt bath tempering treatment described in Step 2: The tempering medium is nitrate salt, the tempering temperature is 200 - 250 °C, and the tempering time is 240 - 300 min; the nitrate salt is a mixture of potassium nitrate and sodium nitrite in a mass ratio of 1:

1.

10. The heat treatment process method of a spherical roller bearing ring according to claim 1, characterized in that The qualified standards for the inspection described in Step 2 are as follows: For martensite structure within 3 mm: 2 - 4 grades; troostite structure less than grade 1; hardness: 59 - 64 HRC; For martensite structure outside 3 mm: 2 - 4 grades; troostite structure less than grade 2; hardness: 59 - 64 HRC; The retained austenite content is less than 5%.

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