Shaping process for bearing ring after heat treatment

Abstract

The invention discloses a shaping process after heat treatment of a bearing ring, and belongs to the field of heat treatment processing of bearing rings. Cleaning before ring sleeving; quenching and heating; salt bath cooling; performing air cooling; cleaning and rust prevention; carrying out tempering treatment; measuring the ellipse deformation of the ferrule after tempering; carrying out secondary tempering treatment; measuring the ellipse deformation of the ferrule after secondary tempering; carrying out stable stress tempering; and measuring the ellipse deformation of the ferrule after stable stress tempering. Compared with the prior art, the process has the advantages that the percent of pass of elliptical deformation after heat treatment of the ferrule can be increased from 85-90% to 95-98%, the quality of a product group is improved, and the production cost is reduced. Through a post-tempering top shape test, the over-top amount range during post-tempering top shape is determined, and meanwhile, the top tool is applied, so that the method is simple, easy to operate and low in cost. According to the inner diameter of a processed product, the 12.9-grade bolts, nuts and sleeves with different durable sizes are selected.

Description

Technical Field

[0001] This invention relates to the field of heat treatment processing technology for bearing rings, and more specifically to a shaping process for bearing rings after heat treatment. Background Technology

[0002] Bearing rings are ring-shaped products. After quenching and cooling, they are subjected to two types of stress. The first is structural stress, caused by the transformation of the matrix structure from pearlite to martensite, resulting in internal stress due to the asynchronous transformation of the surface and core structures during quenching. The second is thermal stress, caused by the different cooling rates of the surface and core during quenching, leading to a temperature gradient and uneven thermal expansion and contraction. When bearing rings are subjected to these two types of stress, a certain amount of deformation (hereinafter referred to as elliptic deformation) will occur. If the elliptic deformation of some rings exceeds the standard requirements, manual reshaping is required to correct it and ensure that the elliptic deformation is within the acceptable range.

[0003] Currently, the shaping method after heat treatment for bearing rings with an outer diameter of 100-250mm is as follows: After the rings are quenched and cooled, and after cleaning and rust prevention, before tempering, they are manually shaped. The shaping method is to hammer the rings that have elliptical deformation exceeding the standard requirements, that is, to use an iron bar to hammer the rings to shape the elliptical deformation within the acceptable range. Then the rings are tempered.

[0004] The reshaping method for elliptical deformation of race rings has certain drawbacks: First, although the elliptical deformation is within acceptable limits after reshaping, some race rings will exceed the standard requirements again after tempering, resulting in scrap. Second, race rings obtain a quenched martensitic structure after quenching and cooling, making them harder and more brittle. After hammer forming, some race rings with special structures may develop obvious cracks or micro-cracks within the structure, resulting in scrap or affecting product quality. Summary of the Invention

[0005] In view of this, the present invention provides a shaping process for bearing rings after heat treatment. This solves the technical problems encountered in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A shaping process for bearing rings after heat treatment includes the following steps:

[0008] (1) Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements;

[0009] (2) Cleaning before ring assembly: pre-cleaning removes impurities on the surface of the rings to ensure that the appearance color of the rings is consistent after quenching and tempering.

[0010] (3) Quenching heating: heating temperature: 830~860℃, heating time: 60~80min; salt bath cooling: salt temperature: 160~190℃, water content in salt bath: 0%~1.2%, cooling time: 5~8min;

[0011] (4) Air cooling: Air cooling is divided into 3 stations, and the air cooling time for each station is 5 to 8 minutes. After air cooling, the surface temperature of the ring is ≤50℃.

[0012] (5) Cleaning and rust prevention: Immersion cleaning is adopted, with three stations in total, and each station takes 8 to 10 minutes to clean.

[0013] (6) Tempering treatment: Tempering is carried out using an air tempering furnace. Tempering temperature: 160~190℃, tempering time: 210min~270min;

[0014] (7) Measurement of elliptical deformation of the ring after tempering: Adjust the measuring instrument using standard parts. After the tempered ring cools to room temperature, measure the elliptical deformation. Place the ring with qualified elliptical deformation on the tray, mark it, and move it separately. For the ring with unqualified elliptical deformation, use the measuring instrument to measure the lowest point of the elliptical deformation, i.e. the direction of the minor axis. Use the top tool to support the ring along the direction of the minor axis. Use a wrench to turn the nut clockwise to push the elliptical ring to a circle. Then continue to use the wrench to turn the nut clockwise to push it over to 0.20mm~0.30mm.

[0015] (8) Secondary tempering treatment: The ring with the top fixture is placed in an air tempering furnace for secondary tempering treatment;

[0016] (9) Measurement of elliptical deformation of the ring after secondary tempering: Use standard parts to adjust the measuring instrument. After the tempered ring cools to room temperature, use a wrench to turn the nut counterclockwise, remove the top fixture, and measure the elliptical deformation.

[0017] (10) Stress stabilization tempering: Stress stabilization tempering is performed on the collar after the top tooling is removed;

[0018] (11) Measurement of elliptical deformation of rings after stress tempering: Use standard parts to adjust the measuring instrument. After the rings have been stress tempered and cooled to room temperature, measure the elliptical deformation. After the elliptical deformation is qualified, place them on a special tray, mark them, and move them separately.

[0019] Preferably, the arrangement in step (1) is as follows: the number of layers is 2 to 4, and there is a gap between the rings in each layer.

[0020] Preferably, the protective atmosphere in the quenching heating in step (3) is nitrogen + methanol dripping + propane, furnace pressure: 150~220Pa; furnace carbon potential CP%: 0.65~0.9.

[0021] Preferably, the three stations in step (5) include: a. ultrasonic cleaning, frequency 28-30KHZ, water temperature 40-60℃; b. foaming cleaning, water temperature 40-60℃; c. rust prevention treatment, water temperature 6-10℃, containing a sodium nitrite aqueous solution with a concentration of 0.5-0.8%.

[0022] Preferably, in the secondary tempering process described in step (8), the tempering temperature is 160-190°C and the tempering time is 210-270 min.

[0023] Preferably, the tempering temperature in step (10) during the stable stress tempering is 160-180°C, and the tempering time is 210-270 min.

[0024] In this invention, the heat treatment (quenching and tempering) of the ring is carried out using a protective atmosphere roller hearth furnace salt bath martensitic quenching production line.

[0025] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Compared with the existing process, the forming method has been changed from hammering to top forming. First, it reduces the noise generated by the hammering between metals on the production site, and at the same time reduces the impact damage to the bearing rings, ensuring the appearance quality of the bearing rings. Second, hammering is prone to producing obvious cracks that cause scrap, and it is also prone to producing micro-cracks that are not visible to the naked eye. After the finished bearing is assembled, it will fail prematurely during use.

[0027] 2. Compared with existing processes, the ovals that have passed the heat treatment and deformation test and the shaped rings that have passed the shaping test are separated, clearly marked, and moved individually, which facilitates subsequent processing and ensures product quality.

[0028] 3. Compared with existing processes, the pass rate of elliptical deformation after heat treatment of the ring can be increased from 85-90% to 95-98%, thereby improving product quality and reducing production costs.

[0029] 4. Through the top-forming test after tempering, the range of over-forming distance during tempering was determined. A top-forming fixture was used, which is simple, easy to operate, and low in cost. Based on the inner diameter of the processed product, durable 12.9 grade bolts, nuts, and sleeves of different sizes were selected.

[0030] 5. After removing the top fixture, an additional stress-stabilizing tempering process is performed to eliminate the remaining elastic stress during top shaping, ensuring that the product will not be deformed during grinding due to residual stress. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the elliptical deformation of the ring after heat treatment;

[0033] Figure 2 A schematic diagram showing how the top fixture supports the collar along the minor axis of the elliptical deformation.

[0034] Figure 3 This is a diagram illustrating how the elliptical collar can be reshaped into a circle after the nut is turned clockwise.

[0035] Figure 4 The diagram shows the process of turning the nut clockwise by 0.20mm to 0.30mm past the top of the collar.

[0036] in, Figure 1 In the middle: 1 - the short axis direction, the low point; 2 - the long axis direction, the high point;

[0037] Figure 2 In the middle: 1-sleeve; 2-nut; 3-bolt. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment provides a shaping process for bearing rings after heat treatment, including the following steps:

[0041] The heat treatment (quenching and tempering) of the rings is carried out using a protective atmosphere roller hearth furnace salt bath martensitic quenching production line.

[0042] 1.1 Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements. The number of layers is 3, with gaps between the rings in each layer, so that they do not touch each other.

[0043] 1.2 Pre-cleaning of the race rings: Pre-cleaning removes residual cutting fluid, dust, oil, and other impurities from the race ring surface to ensure a consistent appearance and color after quenching and tempering. The pre-cleaning process involves both cleaning with a cleaning agent and rinsing with clean water. Cleaning temperature: 60℃, cleaning time per pass: 7 minutes; after cleaning, drying is performed at 130℃ for 7 minutes.

[0044] 1.3 Quenching heating: Heating temperature: 835℃, heating time: 70min.

[0045] 1.4 Protective atmosphere: nitrogen + methanol dripping + propane; furnace pressure: 200 Pa; furnace carbon potential CP%: 0.70; 1.5 Cooling: Salt bath cooling is adopted, with the moving platform moving up and down and the salt tank stirring motor running to improve the salt cooling performance. Salt temperature: 180℃, water content in salt bath: 0.40%, cooling time: 7min.

[0046] 1.6 Air cooling: Air cooling is divided into 3 stations, with each station having an air cooling time of 7 minutes. After air cooling, the surface temperature of the bearing ring is ≤50℃.

[0047] 1.7 Cleaning and Rust Prevention: Immersion cleaning, with three stations, each station cleaning time 8 minutes: 1. Ultrasonic cleaning, frequency 28KHZ, water temperature 60℃; 2. Foaming cleaning, water temperature 60℃; 3. Rust prevention treatment, water temperature 8℃, the cold water station contains a 0.6% sodium nitrite aqueous solution for rust prevention.

[0048] 1.8 Tempering treatment: Tempering was performed using an air tempering furnace. Tempering temperature: 180℃, tempering time: 240min.

[0049] 1.9 Measurement of Elliptical Deformation of Rings After Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, measure the elliptical deformation. The standard requires that the elliptical deformation of the NN3024 inner ring should be ≤0.15mm. After measurement, 25% of the rings should not meet the elliptical deformation requirement. Rings with acceptable elliptical deformation should be placed on a special tray, clearly labeled, and moved individually. For ferrules with unacceptable elliptical deformation, use measuring instruments to measure the lowest point of the elliptical deformation, i.e., along the minor axis. Use a jack (NN3024 inner ring with an inner diameter of 120mm, select a 70mm long, 16mm diameter, 12.9 grade hex bolt + a 16mm diameter, 12.9 grade nut + a 17mm inner diameter socket) to support the ferrule along the minor axis. Use a wrench to turn the nut clockwise, gradually pushing the elliptical ferrule to a round shape. Continue to turn the wrench clockwise until it reaches 0.25mm beyond the target.

[0050] 2.0 Secondary Tempering Treatment: The ring with the top fixture is placed in an air tempering furnace for secondary tempering treatment. Tempering temperature: 160℃, tempering time: 240min.

[0051] 2.1 Measurement of Elliptical Deformation of Rings After Secondary Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, use a wrench to turn the nut counterclockwise to remove the top fixture and measure the elliptical deformation. The standard requires that the elliptical deformation of the NN3024 inner ring should be ≤0.15mm. Measurements showed that 92% of the rings met the elliptical deformation requirements. Rings that failed the elliptical deformation test after top forming and secondary tempering were scrapped.

[0052] 2.2 Stress-stabilizing tempering: Minor elastic deformation stress remains inside the collar after removing the top fixture. To prevent the collar from springing back, a stress-stabilizing tempering treatment should be performed. Stress-stabilizing tempering temperature: 160℃; tempering time: 240min.

[0053] 2.3 Measurement of Elliptical Deformation of Rings After Stress-Standing Tempering: Using standard parts, adjust the measuring instrument. After the rings have been stress-stressed and cooled to room temperature, measure the elliptical deformation. The standard requires that the elliptical deformation of the NN3024 inner ring should be ≤0.15mm. After measurement, 100% of the rings passed the elliptical deformation test. Rings with qualified elliptical deformation were placed on a special tray, clearly labeled, and moved individually.

[0054] Example 2

[0055] This embodiment provides a shaping process for the outer ring of a 7022AC after heat treatment, including the following steps:

[0056] The heat treatment (quenching and tempering) of the rings is carried out using a protective atmosphere roller hearth furnace salt bath martensitic quenching production line.

[0057] 1.1 Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements. The number of layers is 2, with gaps between the rings in each layer, so that they do not touch each other.

[0058] 1.2 Pre-cleaning of the race rings: Pre-cleaning removes residual cutting fluid, dust, oil, and other impurities from the race ring surface to ensure a consistent appearance and color after quenching and tempering. The pre-cleaning process involves both cleaning with a cleaning agent and rinsing with clean water. Cleaning temperature: 60℃, cleaning time per pass: 8 minutes; after cleaning, drying is performed at 130℃ for 8 minutes.

[0059] 1.3 Quenching heating: Heating temperature: 845℃, heating time: 70min.

[0060] 1.4 Protective atmosphere: nitrogen + methanol dripping + propane; furnace pressure: 200 Pa; furnace carbon potential CP%: 0.70; 1.5 Cooling: Salt bath cooling is adopted, with the moving platform moving up and down and the salt tank stirring motor running to improve the salt cooling performance. Salt temperature: 180℃, water content in salt bath: 0%, cooling time: 8min.

[0061] 1.6 Air cooling: Air cooling is divided into 3 stations, with an air cooling time of 8 minutes for each station. After air cooling, the surface temperature of the ring is ≤50℃.

[0062] 1.7 Cleaning and Rust Prevention: Immersion cleaning, with three stations, each station cleaning time 8 minutes: 1. Ultrasonic cleaning, frequency 28KHZ, water temperature 60℃; 2. Foaming cleaning, water temperature 60℃; 3. Rust prevention treatment, water temperature 8℃, the cold water station contains a 0.6% sodium nitrite aqueous solution for rust prevention.

[0063] 1.8 Tempering treatment: Tempering was performed using an air tempering furnace. Tempering temperature: 180℃, tempering time: 240min.

[0064] 1.9 Measurement of Elliptical Deformation of Rings After Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, measure the elliptical deformation. The standard requires that the elliptical deformation of the 7022AC outer ring should be ≤0.20mm. After measurement, 30% of the rings should have unacceptable elliptical deformation. Rings with acceptable elliptical deformation should be placed on a special tray, clearly labeled, and moved individually. For rings with unacceptable elliptical deformation, use measuring instruments to measure the lowest point of the elliptical deformation, i.e., along the minor axis. Use a jack (the outer and inner diameter of the 7022AC outer ring is 154mm; select a 12.9 grade hex bolt with a length of 70mm and a diameter of 16mm, plus a 16mm diameter, 12.9 grade nut and a 17mm inner diameter sleeve) to support the ring along the minor axis. Use a wrench to turn the nut clockwise, gradually pushing the elliptical ring to a round shape. Continue to turn the wrench clockwise until the deformation is reduced to 0.25mm.

[0065] 2.0 Secondary Tempering Treatment: The ring with the top fixture is placed in an air tempering furnace for secondary tempering treatment. Tempering temperature: 160℃, tempering time: 240min.

[0066] 2.1 Measurement of Elliptical Deformation of the Rings after Secondary Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, use a wrench to turn the nut counterclockwise to remove the top fixture and measure the elliptical deformation. The standard requires that the elliptical deformation of the 7022AC outer ring should be ≤0.20mm. After measurement, 95% of the rings passed the elliptical deformation test. Rings that failed the elliptical deformation test after top forming and secondary tempering were scrapped.

[0067] 2.2 Stress-stabilizing tempering: Minor elastic deformation stress remains inside the collar after removing the top fixture. To prevent the collar from springing back, a stress-stabilizing tempering treatment should be performed. Stress-stabilizing tempering temperature: 160℃; tempering time: 240min.

[0068] 2.3 Measurement of Elliptical Deformation of Rings After Stress-Standing Tempering: Using standard parts, the measuring instrument was adjusted. After the rings under stress-stabilized tempering cooled to room temperature, the elliptical deformation was measured. The standard requires that the elliptical deformation of the 7022AC outer ring should be ≤0.20mm. After measurement, 100% of the rings passed the elliptical deformation test. Rings with qualified elliptical deformation were placed on a dedicated tray, clearly labeled, and moved individually.

[0069] Example 3

[0070] This embodiment provides a shaping process for the outer ring of 6030 after heat treatment, including the following steps:

[0071] The heat treatment (quenching and tempering) of the rings is carried out using a protective atmosphere roller hearth furnace salt bath martensitic quenching production line.

[0072] 1.1 Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements. The number of layers is 2, with gaps between the rings in each layer, so that they do not touch each other.

[0073] 1.2 Pre-cleaning of the race rings: Pre-cleaning removes residual cutting fluid, dust, oil, and other impurities from the race ring surface to ensure a consistent appearance and color after quenching and tempering. The pre-cleaning process involves both cleaning with a cleaning agent and rinsing with clean water. Cleaning temperature: 60℃, cleaning time per pass: 8 minutes; after cleaning, drying is performed at 130℃ for 8 minutes.

[0074] 1.3 Quenching heating: Heating temperature: 850℃, heating time: 80min.

[0075] 1.4 Protective atmosphere: nitrogen + methanol dripping + propane; furnace pressure: 200 Pa; furnace carbon potential CP%: 0.70; 1.5 Cooling: Salt bath cooling is adopted, with the stirring platform moving up and down and the salt tank stirring motor running to improve the salt cooling performance. Salt temperature: 180℃, water content in salt bath: 0.40%, cooling time: 8min.

[0076] 1.6 Air cooling: Air cooling is divided into 3 stations, with an air cooling time of 8 minutes for each station. After air cooling, the surface temperature of the ring is ≤50℃.

[0077] 1.7 Cleaning and Rust Prevention: Immersion cleaning, with three stations, each station cleaning time 8 minutes: 1. Ultrasonic cleaning, frequency 28KHZ, water temperature 60℃; 2. Foaming cleaning, water temperature 60℃; 3. Rust prevention treatment, water temperature 8℃, the cold water station contains a 0.6% sodium nitrite aqueous solution for rust prevention.

[0078] 1.8 Tempering treatment: Tempering was performed using an air tempering furnace. Tempering temperature: 180℃, tempering time: 240min.

[0079] 1.9 Measurement of Elliptical Deformation of Rings After Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, measure the elliptical deformation. The standard requires that the elliptical deformation of the 6030 outer ring should be ≤0.22mm. After measurement, 35% of the rings failed the elliptical deformation test. Rings with acceptable elliptical deformation were placed on a special tray, clearly labeled, and moved individually. For rings with unacceptable elliptical deformation, use measuring instruments to measure the lowest point of the elliptical deformation, i.e., along the minor axis. Use a jack (for a 6030 outer ring with an outer inner diameter of 200mm, select a 12.9 grade hex bolt with a length of 100mm and a diameter of 18mm, plus an 18mm diameter, 12.9 grade nut and a sleeve with an inner diameter of 19mm) to support the ring along the minor axis. Use a wrench to turn the nut clockwise, gradually pushing the elliptical ring to a round shape. Continue to turn the wrench clockwise to push the nut further to 0.30mm.

[0080] 2.0 Secondary Tempering Treatment: The ring with the top fixture is placed in an air tempering furnace for secondary tempering treatment. Tempering temperature: 160℃, tempering time: 240min.

[0081] 2.1 Measurement of Elliptical Deformation of Rings After Secondary Tempering: Using standard parts, adjust the measuring instrument. After the tempered rings have cooled to room temperature, use a wrench to turn the nut counterclockwise to remove the top fixture and measure the elliptical deformation. The standard requires that the elliptical deformation of the 6030 outer ring should be ≤0.22mm. Measurements showed that 96% of the rings met the elliptical deformation requirements. Rings that failed the elliptical deformation test after top forming and secondary tempering were scrapped.

[0082] 2.2 Stress-stabilizing tempering: Minor elastic deformation stress remains inside the collar after removing the top fixture. To prevent the collar from springing back, a stress-stabilizing tempering treatment should be performed. Stress-stabilizing tempering temperature: 160℃; tempering time: 240min.

[0083] 2.3 Measurement of Elliptical Deformation of Rings After Stress-Tempering: The measuring instrument was adjusted using standard parts. After the rings under stress-tempering were cooled to room temperature, the elliptical deformation was measured. The standard requires that the elliptical deformation of the 6030 outer ring should be ≤0.22mm. After measurement, 100% of the rings passed the elliptical deformation test. Rings with qualified elliptical deformation were placed on a special tray, clearly labeled, and moved individually.

[0084] Comparative Example 1 (Existing Process)

[0085] The heat treatment (quenching and tempering) of the rings is carried out using a protective atmosphere roller hearth furnace salt bath martensitic quenching production line.

[0086] 1.1 Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements. The number of layers is 3, with gaps between the rings in each layer, so that they do not touch each other.

[0087] 1.2 Pre-cleaning of the race rings: Pre-cleaning removes residual cutting fluid, dust, oil, and other impurities from the race ring surface to ensure a consistent appearance and color after quenching and tempering. The pre-cleaning process involves both cleaning with a cleaning agent and rinsing with clean water. Cleaning temperature: 60℃, cleaning time per pass: 8 minutes; after cleaning, drying is performed at 130℃ for 8 minutes.

[0088] 1.3 Quenching heating: Heating temperature: 845℃, heating time: 70min.

[0089] 1.4 Protective atmosphere: nitrogen + methanol dripping + propane; furnace pressure: 200 Pa; furnace carbon potential CP%: 0.7; 1.5 Cooling: Salt bath cooling is adopted, with the stirring platform moving up and down and the salt tank stirring motor running to improve the salt cooling performance. Salt temperature: 180℃, water content in salt bath: 0.5%, cooling time: 8min.

[0090] 1.6 Air cooling: Air cooling is divided into 3 stations, with an air cooling time of 8 minutes for each station. After air cooling, the surface temperature of the ring is ≤50℃.

[0091] 1.7 Cleaning and Rust Prevention: Immersion cleaning, with three stations, each station taking 8-10 minutes: 1. Ultrasonic cleaning, frequency 28kHz, water temperature 50℃; 2. Foaming cleaning, water temperature 50℃; 3. Rust prevention treatment, water temperature 8℃, with the cold water station containing a 0.6% sodium nitrite aqueous solution for rust prevention.

[0092] 1.8 Measurement of Elliptical Deformation of Rings After Quenching: Using standard parts, adjust the measuring instrument. Remove the cleaned rings from the fixture and measure their elliptical deformation. Rings with acceptable elliptical deformation are returned to the fixture. For rings with unacceptable elliptical deformation, use the measuring instrument to measure the highest point of the elliptical deformation, i.e., along the major axis. The worker holds an iron bar with one hand and supports the ring with the other, forcefully striking the highest point of the elliptical deformation. After striking, measure the elliptical deformation of the ring again. If it is acceptable, place it back into the fixture; if not, repeat the above steps until the elliptical deformation is within the acceptable range.

[0093] 1.9 Tempering Treatment: Tempering is performed using an air tempering furnace. Tempering temperature: 180℃, tempering time: 240min. Rings that fail the elliptical deformation test within the tray are not allowed to proceed to the next process and must be scrapped.

[0094] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0095] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A shaping process for bearing rings after heat treatment, characterized in that, Includes the following steps: (1) Placement of rings: Place the machined rings in the heat-resistant steel fixture according to the process requirements; (2) Cleaning before ring assembly: Cleaning removes impurities from the surface of the rings to ensure that the rings have a consistent appearance color after quenching and tempering. (3) Quenching heating: heating temperature: 830~860℃, heating time: 60~80min; salt bath cooling: salt temperature: 160~190℃, water content in salt bath: 0%~1.2%, cooling time: 5~8min; (4) Air cooling: Air cooling is divided into 3 stations, and the air cooling time for each station is 5 to 8 minutes. After air cooling, the surface temperature of the ring is ≤50℃. (5) Cleaning and rust prevention: Immersion cleaning is adopted, with three stations in total, and each station takes 8 to 10 minutes to clean. (6) Tempering treatment: Tempering is carried out using an air tempering furnace. Tempering temperature: 160~190℃, tempering time: 210min~270min; (7) Measurement of elliptical deformation of the ring after tempering: Adjust the measuring instrument using standard parts. After the tempered ring cools to room temperature, measure the elliptical deformation. Place the ring with qualified elliptical deformation on the tray, mark it, and move it separately. For the ring with unqualified elliptical deformation, use the measuring instrument to measure the lowest point of the elliptical deformation, i.e. the direction of the minor axis. Use the top tool to support the ring along the direction of the minor axis. Use a wrench to turn the nut clockwise to push the elliptical ring to a circle. Then continue to use the wrench to turn the nut clockwise to push it over to 0.20mm~0.30mm. (8) Secondary tempering treatment: The ring with the top fixture is placed in an air tempering furnace for secondary tempering treatment; (9) Measurement of elliptical deformation of the ring after secondary tempering: Use standard parts to adjust the measuring instrument. After the tempered ring cools to room temperature, use a wrench to turn the nut counterclockwise, remove the top fixture, and measure the elliptical deformation. (10) Stress stabilization tempering: Stress stabilization tempering is performed on the collar after the top tooling is removed; (11) Measurement of elliptical deformation of rings after stress tempering: Use standard parts to adjust the measuring instrument. After the rings have been stress tempered and cooled to room temperature, measure the elliptical deformation. After the elliptical deformation is qualified, place them on a special tray, mark them, and move them separately.

2. The bearing ring shaping process after heat treatment according to claim 1, characterized in that, The arrangement described in step (1) is as follows: the number of layers is 2 to 4, and there is a gap between the rings in each layer.

3. The bearing ring shaping process after heat treatment according to claim 1, characterized in that, In step (3), the protective atmosphere for quenching heating is nitrogen + methanol dripping + propane, furnace pressure: 150~220Pa; furnace carbon potential CP%: 0.65~0.

9.

4. The bearing ring shaping process after heat treatment according to claim 1, characterized in that, The three stations mentioned in step (5) include: a. ultrasonic cleaning, frequency 28-30KHZ, water temperature 40-60℃; b. foaming cleaning, water temperature 40-60℃; c. rust prevention treatment, water temperature 6-10℃, containing a sodium nitrite aqueous solution with a concentration of 0.5-0.8%.

5. The bearing ring shaping process after heat treatment according to claim 1, characterized in that, In step (8), the tempering temperature during the secondary tempering process is 160-190℃, and the tempering time is 210-270 min.

6. The bearing ring shaping process after heat treatment according to claim 1, characterized in that, In step (10), the tempering temperature during the stabilizing stress tempering is 160-180℃, and the tempering time is 210-270 min.

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