Tapered roller bearing ring heat treatment process
By adopting the salt bath quenching process and strictly controlling the heating time, the deformation, pollution and environmental protection problems caused by traditional oil bath quenching are solved, and a more efficient, environmentally friendly and safe heat treatment effect is achieved.
Patent Information
- Application Number
- CN202411979872.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-03-28
AI Technical Summary
There are deformation, pollution and environmental protection problems during the oil bath quenching of traditional small tapered roller bearings, and pose hidden dangers to the environment and safety.
The salt bath quenching process of tapered roller bearing ring is adopted. By strictly controlling the heating time and the water content of the salt tank, combined with the use of nitrogen and propane, the austenitization treatment, quenching, tempering and other steps are carried out to reduce deformation and pollution and improve environmental protection.
It effectively reduces the deformation and taper of tapered roller bearings, reduces pollution, improves environmental protection and safety, and reduces usage costs.
Smart Images
Figure CN119710203A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of various industrial reducers, textile machinery transmission shafts, washing equipment and other parts, in particular to a heat treatment process for tapered roller bearing rings. Background Art
[0002] Traditionally, small tapered roller bearings are processed by oil bath quenching. Low temperature transformation leads to more paralysis and also pollutes the environment. The oil used in the oil bath quenching process is prone to produce smoke, and the water used for post-cleaning must be chemically treated before it can be discharged. At the same time, the melting point is low, which poses a great safety hazard to the environment and safety. Summary of the invention
[0003] In view of the above problems, the purpose of this application is to provide a heat treatment process for tapered roller bearing rings, so that it can reduce deformation, reduce taper, and reduce pollution.
[0004] In order to achieve some or all of the above purposes or other purposes, the present application provides the following technical solution: a heat treatment process for a tapered roller bearing ring, the specific steps of which include: S1. Pre-clean the surface of the tapered roller ring for 20-40 minutes and dry it for 10-30 minutes; S2, heating to 820℃-850℃ for 75-200min and keeping warm; S3. Place the tapered roller ring into the salt bath medium, cool to 170℃-190℃, and quench for 20-40min; S4, air cooling; S5, secondary cleaning; S6. Deep cooling, cooling the tapered roller ring to 5℃-10℃, so that austenite continues to transform into martensite; S7, tempering at 190℃-220℃, keeping warm for 8-10h, so that the quenched martensite is transformed into tempered martensite and the residual austenite is eliminated; S8. Air cool the surface of the tapered roller ring for 30-80 minutes, and then clean it for 20-40 minutes.
[0005] Furthermore, the specific method of step S3 includes: introducing nitrogen at a flow rate of 10-16m³ / h to discharge the air in the heating furnace.
[0006] Furthermore, the specific method of step S3 includes: introducing propane into the heating furnace at a flow rate of 0.5-1.2 L / h.
[0007] Furthermore, the specific method of step S3 includes: carbon potential 0.40%-0.80%.
[0008] Furthermore, the specific method of step S3 includes: front ventilation chamber purge nitrogen: 6-10m³ / h, rear ventilation chamber purge nitrogen: 6-10m³ / h, oxygen probe purge gas: 150-250 L / h.
[0009] Furthermore, the cylindrical roller bearing ring has a specification of 32048 / P4.01, a diameter of 360 mm, a width of 57 mm, and a wall thickness of 19 mm.
[0010] Furthermore, the cylindrical roller bearing ring is made of GCr15SiMn material.
[0011] Furthermore, the specific method of step S2 includes: product wall thickness (unit: mm)*1.0≤heating and heat preservation time (unit: min)≤product wall thickness (unit: mm)*1.2.
[0012] Furthermore, the specific steps of the tapered roller bearing ring heat treatment process include: S1. Pre-clean the surface of the tapered roller ring for 20 minutes and dry it for 20 minutes; S2, austenitizing treatment is carried out by heating to 820℃ for 90min; carbon potential is 0.55%; nitrogen is introduced at a flow rate of 12m³ / h; propane is introduced at a flow rate of 1.0 L / h; nitrogen purge in the front ventilation chamber: 8m³ / h, nitrogen purge in the rear ventilation chamber: 8m³ / h, oxygen probe purge gas: 200 L / h; S3. Place the tapered roller ring in a salt bath, cool to 175°C, and quench for 20 minutes; S4, air cooling; S5, secondary cleaning; S6, deep cooling, to cool the tapered roller ring to 7°C; S7, tempering at 200℃, keeping warm for 8h; S8. Air cool the surface of the tapered roller ring for 30 minutes and then clean it for 20 minutes.
[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. Reducing deformation: For GCr15SiMn, in order to ensure uniform martensitic structural transformation, it is necessary to ensure smaller heat treatment deformation. The present application strictly controls the heating time and the water content of the salt tank; 2. Reducing taper: The salt bath quenching process strictly controls the heating temperature of the salt tank. Compared with the low-temperature transformation of martensite, the salt bath heating temperature is higher, which reduces the taper generated during the quenching cooling process due to the different thicknesses of the upper and lower end faces; 3. Reducing pollution: The present application cleans the residual brine after use and introduces it into the quenching tank for recycling, so there is no need to consider the above problems. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is the process curve of the present invention; Figure 2 It is a schematic diagram of the structure of a tapered roller bearing ring. DETAILED DESCRIPTION
[0015] In order to make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0016] See attached Figure 1-2 The specific steps of the tapered roller bearing ring heat treatment process include: S1. Pre-clean the surface of the tapered roller ring for 20-40 minutes and dry it for 10-30 minutes; S2, heating to 820℃-850℃ for 75-200min and keeping warm; S3. Place the tapered roller ring in a salt bath medium, cool to 170℃-190℃, and quench for 20-40min. The salt bath quenching process strictly controls the salt bath heating temperature. Compared with the low-temperature transformation of martensite, the salt bath heating temperature is higher, which reduces the taper generated during the quenching cooling process due to the different thickness of the upper and lower end faces. S4, air cooling; S5, secondary cleaning; S6. Deep cooling, cooling the tapered roller ring to 5℃-10℃, so that austenite continues to transform into martensite; S7, tempering at 190℃-220℃, keeping warm for 8-10h, so that the quenched martensite is transformed into tempered martensite and the residual austenite is eliminated; S8. Air cool the surface of the tapered roller ring for 30-80 minutes and then clean it for 20-40 minutes. The oil used in the oil bath quenching process is prone to produce smoke, and the water used for post-cleaning must be chemically treated before it can be discharged. At the same time, it has a low melting point, which poses a great safety hazard to the environment and safety. This application uses the residual brine after cleaning and introduces it into the quenching tank for recycling, so there is no need to consider the above problems.
[0017] The specific method of step S3 includes: introducing nitrogen at a flow rate of 10-16m³ / h to discharge the air in the heating furnace.
[0018] The specific method of step S3 includes: introducing propane into the heating furnace at a flow rate of 0.5-1.2 L / h.
[0019] The specific method of step S3 includes: carbon potential 0.40%-0.80%.
[0020] The specific method of step S3 includes: front ventilation chamber purge nitrogen: 6-10m³ / h, rear ventilation chamber purge nitrogen: 6-10m³ / h, oxygen probe purge gas: 150-250 L / h.
[0021] The cylindrical roller bearing ring specification is 32048 / P4.01, with a diameter of 360mm, a width of 57mm, and a wall thickness of 19mm.
[0022] The cylindrical roller bearing ring is made of GCr15SiMn; the small tapered roller bearing uses GCr15SiMn as raw material. This material has good wear resistance and hardenability. The innovative use of post-cleaning brine introduced into the quenching tank recycles the quenching salt, which saves costs and protects the environment.
[0023] 1. The specific method of step S2 includes: product wall thickness (unit mm) * 1.0 ≤ heating and holding time (unit min) ≤ product wall thickness (unit mm) * 1.2; for GCr15SiMn material, in order to ensure uniform martensitic structure transformation, it is necessary to ensure small heat treatment deformation. This application strictly controls the heating time and the water content of the salt tank. For example: product specification 32048 / P4.01, diameter 360mm, width 57mm, wall thickness 19mm, the holding time should be between 19*1.0-19*1.2min.
[0024] Preferably, the specific steps of the tapered roller bearing ring heat treatment process include: S1. Pre-clean the surface of the tapered roller ring for 20 minutes and dry it for 20 minutes; S2, austenitizing treatment is carried out by heating to 820℃ for 90min; carbon potential is 0.55%; nitrogen is introduced at a flow rate of 12m³ / h; propane is introduced at a flow rate of 1.0 L / h; nitrogen purge in the front ventilation chamber: 8m³ / h, nitrogen purge in the rear ventilation chamber: 8m³ / h, oxygen probe purge gas: 200 L / h; S3. Place the tapered roller ring in a salt bath, cool to 175°C, and quench for 20 minutes; S4, air cooling; S5, secondary cleaning; S6, deep cooling, to cool the tapered roller ring to 7°C; S7, tempering at 200℃, keeping warm for 8h; S8. Air cool the surface of the tapered roller ring for 30 minutes and then clean it for 20 minutes.
[0025] In the conventional process, oil bath quenching is performed at 70°C. After the tapered roller bearing is deformed during heat treatment, due to the small width of the product, once the product has too large a taper, it is difficult to handle and there is a risk of direct scrapping. This application uses salt bath quenching at 175°C. Due to the increase in temperature, the taper of the product is reduced and the problem is solved. The oil used in the product quenching process is prone to produce smoke, and the post-cleaning water must be chemically treated before it can be discharged. After changing to salt bath quenching, the harm of chemical substances to the environment is reduced, and the post-cleaning water can be directly pumped into the quenching tank for recycling, which is both environmentally friendly and reduces the cost of use.
[0026] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.
Claims
1. The tapered roller bearing ring heat treatment process is characterized by: The specific steps include: S1. Pre-clean the surface of the tapered roller ring for 20-40 minutes and dry it for 10-30 minutes; S2, heating to 820℃-850℃ for 75-200min and keeping warm; S3. Place the tapered roller ring into the salt bath medium, cool to 170℃-190℃, and quench for 20-40min; S4, air cooling; S5, secondary cleaning; S6. Deep cooling, cooling the tapered roller ring to 5℃-10℃, so that austenite continues to transform into martensite; S7, tempering at 190℃-220℃, keeping warm for 8-10h, so that the quenched martensite is transformed into tempered martensite and the residual austenite is eliminated; S8. Air cool the surface of the tapered roller ring for 30-80 minutes, and then clean it for 20-40 minutes.
2. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific method of step S3 includes: introducing nitrogen at a flow rate of 10-16m³ / h to discharge the air in the heating furnace.
3. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific method of step S3 includes: introducing propane into the heating furnace at a flow rate of 0.5-1.2 L / h.
4. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific method of step S3 includes: carbon potential 0.40%-0.80%.
5. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific method of step S3 includes: front ventilation chamber purge nitrogen: 6-10m³ / h, rear ventilation chamber purge nitrogen: 6-10m³ / h, oxygen probe purge gas: 150-250 L / h.
6. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The cylindrical roller bearing ring specification is 32048 / P4.01, with a diameter of 360mm, a width of 57mm, and a wall thickness of 19mm.
7. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The cylindrical roller bearing ring is made of GCr15SiMn material.
8. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific method of step S2 includes: product wall thickness (unit: mm)*1.0≤heating and heat preservation time (unit: min)≤product wall thickness (unit: mm)*1.
2.
9. The tapered roller bearing ring heat treatment process according to claim 1, characterized in that: The specific steps include: S1. Pre-clean the surface of the tapered roller ring for 20 minutes and dry it for 20 minutes; S2, austenitizing treatment is carried out by heating to 820℃ for 90min; carbon potential is 0.55%; nitrogen is introduced at a flow rate of 12m³ / h; propane is introduced at a flow rate of 1.0 L / h; nitrogen purge in the front ventilation chamber: 8m³ / h, nitrogen purge in the rear ventilation chamber: 8m³ / h, oxygen probe purge gas: 200 L / h; S3. Place the tapered roller ring in a salt bath, cool to 175°C, and quench for 20 minutes; S4, air cooling; S5, secondary cleaning; S6, deep cooling, to cool the tapered roller ring to 7°C; S7, tempering at 200℃, keeping warm for 8h; S8. Air cool the surface of the tapered roller ring for 30 minutes and then clean it for 20 minutes.