CN112609063A - Heat treatment processing technology for high-precision long-life noiseless bearing rolling body - Google Patents
Heat treatment processing technology for high-precision long-life noiseless bearing rolling body Download PDFInfo
- Publication number
- CN112609063A CN112609063A CN202011417148.7A CN202011417148A CN112609063A CN 112609063 A CN112609063 A CN 112609063A CN 202011417148 A CN202011417148 A CN 202011417148A CN 112609063 A CN112609063 A CN 112609063A
- Authority
- CN
- China
- Prior art keywords
- steel ball
- tempering
- temperature
- heat treatment
- cleaning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/36—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for balls; for rollers
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F17/00—Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention relates to a high-precision long-life noiseless bearing rolling body heat treatment processing technology, which comprises the following steps of 1) weighing, cleaning and drying a steel ball to be processed; 2) carrying out low-temperature heating and nitrate bath quenching on the cleaned steel balls; 3) carrying out cryogenic treatment on the quenched steel ball again; 4) tempering the steel ball after deep cooling; 5) cleaning the steel ball after the tempering treatment again; 6) and (5) tempering the steel ball at high temperature after cleaning, and finishing heat treatment. The steel ball has the advantages of high precision, long service life and no abnormal sound, is widely used in the market, can be used on a convection radiator of a 5G/6G communication base station, can also be used on a miniature bearing of aerospace, and has good market prospect.
Description
Technical Field
The invention relates to the technical field of steel ball processing, in particular to a heat treatment processing technology for a high-precision long-life abnormal sound-free bearing rolling body.
Background
The quenching of the bearing steel is an incomplete quenching, a large amount of retained austenite exists after the quenching of the bearing steel ball, and about 20 percent of retained austenite still exists after normal tempering although the retained austenite is reduced. Because the transformation temperature of the martensite structure is-50-250 ℃, the martensite structure transformation of the retained austenite in the bearing part still occurs at normal temperature. When the retained austenite is transformed to the martensite structure, the size or volume of the workpiece can be changed, and the condition can cause early abrasion or failure of the rolling body, which is not allowed by precision-class bearing (ultra-precision class) parts and steel balls in 5/6G communication equipment, aerospace bearings and high-speed rail (motor train, city rail) bearing parts.
Disclosure of Invention
In order to solve the technical problems, the invention provides a heat treatment processing technology of the bearing rolling body with high precision, long service life and no abnormal sound, and the technology has the advantages of ingenious design and perfect process.
The technical scheme of the invention is as follows:
the heat treatment process for high-precision long-life noiseless bearing rolling body includes the following steps,
1) firstly, weighing a certain weight of steel balls to be treated by a self-weighing device, conveying the steel balls to a drum-type ultrasonic cleaning machine for cleaning, using an environment-friendly cleaning agent, and drying by a circulating hot air drying device; the drying temperature is 150 +/-5 ℃, the dried steel ball is fully dried, the surface is free of moisture and foreign matter adhesion, the decarburization or recarburization of the steel ball surface caused by carbon potential fluctuation of the austenitizing furnace is avoided, and the steel ball is prevented from forming soft spots during quenching.
2) Heating the cleaned steel ball at a low temperature until the temperature for austenitizing the steel ball is 840 +/-5 ℃ and the austenitizing time is 65 min; then quenching in a nitrate bath at the salt bath temperature of 175 +/-5 ℃ for 2-3 minutes.
3) And (3) sending the quenched steel ball into a cryogenic treatment device of the strip steel ball turning and automatic timing device again for cryogenic treatment, wherein the cryogenic temperature is 150 +/-5 ℃ and the time is 2H.
4) And (3) electrically heating the steel ball subjected to deep cooling to room temperature, then tempering, and performing primary tempering in equipment with a circulating air medium at the temperature of 140 +/-5 ℃ for 3H.
5) And (3) cleaning the steel ball after the tempering treatment by using a high-pressure type spraying crawler belt type cleaning machine, and removing the residual nitrate on the surface of the steel ball by using an environment-friendly cleaning agent.
6) After cleaning, the steel balls move in the furnace through the drum type circulating air high-temperature tempering equipment, the high-temperature tempering temperature is 170 +/-5 ℃, the tempering time is 3H, each steel ball is fully tempered, the tempering stability is good, the hardness uniformity is good, the hardness dispersion is small, the hardness particle difference reaches less than 0.5HRC, the hardness batch difference reaches less than 0.8HRC, the used heat treatment equipment is Suzhou Zhongmen equipment ZMZ803, and the equipment has the characteristics of high temperature control precision and good tempering stability, and is naturally air-cooled after tempering, and the heat treatment is finished.
The weight of each time the steel balls to be treated are conveyed in the step 1) is 6 kg.
The steel balls to be processed are steel balls with the diameter of below 3.969 mm.
And 4) after the deep cooling treatment in the step 4), the steel ball can be firstly returned to the room temperature and then tempered, and the tempering must be carried out in time after the steel ball is returned to the room temperature and must be controlled within 45 minutes.
The invention has the advantages that the ultrasonic cleaning mode of automatic weighing of feeding each time is adopted, the feeding is uniform, and the cleaning effect of the steel balls can be fully ensured. The cleaning mode ensures that the surface of the steel ball after cleaning has no iron powder attached and no residual moisture on the surface of the dried steel ball enters an austenitizing heating furnace, the possibility of decarburization of the steel ball is reduced, electronic equipment with JTEKT weighing equipment is used, the weighing precision can be controlled within +/-0.3 Kg of the weighing of a set value, and ultrasonic cleaning equipment used is WR95x95x26-3 ultrasonic cleaning belt drying and heating equipment in Thangyajie.
The invention uses the nitrate as the cooling medium of the steel balls with the specification of below 3.969, is a great innovation, and can ensure that the tendency of deformation and crack of the steel balls is greatly reduced.
The cryogenic treatment with the steel ball turning and automatic timing device can fully ensure the cryogenic treatment effect of each steel ball, the residual austenite of the steel ball subjected to the thermal treatment reaches the residual austenite of less than 1 percent (the national standard is less than 15 percent) after the cold treatment, and the special quality requirements of the steel ball with high precision, long service life and no abnormal sound on the dimensional stability are ensured.
The steel ball after the cryogenic treatment is recovered to the room temperature, tempering must be carried out in time, the time must be controlled within 45 minutes, and the risk of steel ball cracking which may occur when the tempering is not in time is prevented.
Cleaning by using a high-pressure spray crawler-type cleaning machine (using an environment-friendly cleaning agent) to remove the nitrate remained on the surface of the steel ball, wherein the used equipment model is FB95x95x26-5 crawler-type cleaning equipment in Thangyajie.
After the steel ball is tempered at high temperature (170 +/-5 ℃ for 3H) by circulating air, the residual structural stress and thermal stress of the steel ball can be removed.
The steel ball produced by the heat treatment process has high precision, long service life and no abnormal sound, is widely used in the market, and not only can be used on a convection radiator of a 5G communication base station, but also can be used on a miniature bearing of aerospace.
Detailed Description
In order to avoid the situation that the size or the volume of a workpiece can be changed when the residual austenite structure is transformed into the martensite structure at normal temperature, the part after heat treatment and quenching needs to be subjected to cryogenic treatment, the residual austenite can be controlled to be less than 1 percent, the wear resistance, the corrosion resistance, the impact toughness and the dimensional stability of the bearing part after the cryogenic treatment are greatly improved, the precision of the bearing part can be greatly improved by the bearing subjected to the cold treatment, and meanwhile, the size of a rolling body (a steel ball or a roller) can not be changed at all under the long-term use state or the storage state no matter under the high-temperature or low-temperature state, so that the annual change rate of the rolling body can be ensured.
In order to meet the national requirements of high-end bearing customers at home and abroad on high precision, long service life and low noise, a special heat treatment production process is established.
Example 1
The heat treatment processing technology for the high-precision long-life abnormal sound-free bearing rolling body comprises the following steps:
1) firstly, weighing a certain weight of steel balls to be treated by a self-weighing device, conveying the steel balls to a drum-type ultrasonic cleaning machine for cleaning, using an environment-friendly cleaning agent, and drying by a circulating hot air drying device; the weight of each steel ball to be treated is 6 kg; the steel ball to be processed is a steel ball with the diameter below 3.969, the steel ball is weighed by using electronic equipment with JTEKT as weighing equipment, the weighing precision can be controlled to be +/-0.3 Kg of the weighing of a set value, and the used ultrasonic cleaning equipment is WR95x95x26-3 ultrasonic cleaning belt drying and heating equipment in Thangyajie; the drying temperature is 150 +/-5 ℃, the dried steel ball is fully dried, the surface is free of moisture and foreign matter adhesion, the decarburization or recarburization of the steel ball surface caused by carbon potential fluctuation of the austenitizing furnace is avoided, and the steel ball is prevented from forming soft spots during quenching.
2) Heating the cleaned steel ball at a low temperature until the temperature for austenitizing the steel ball is 840 +/-5 ℃ and the austenitizing time is 65 min; then quenching in a nitrate bath at the salt bath temperature of 175 +/-5 ℃ for 2-3 minutes.
3) And (3) sending the quenched steel ball into a cryogenic treatment device of the strip steel ball turning and automatic timing device again for cryogenic treatment, wherein the cryogenic temperature is 150 +/-5 ℃ and the time is 2H.
4) And (3) electrically heating the steel ball subjected to deep cooling to room temperature, and then tempering, wherein the tempering is performed for the first time in equipment with a circulating air medium, the temperature is 140 +/-5 ℃, the time is 3H, and the used equipment is RJ8000x3000x250D tempering equipment of Dongdong electric furnace company in Suzhou industrial park.
5) Cleaning the steel ball after the tempering treatment by using a high-pressure type spraying crawler belt type cleaning machine, and removing the residual nitrate on the surface of the steel ball by using an environment-friendly cleaning agent; the equipment model used was a FB95x95x26-5 track type cleaning apparatus from Thangyajie.
6) The high-temperature tempering temperature of the drum-type circulating air high-temperature tempering equipment for moving the steel balls in the furnace is 170 +/-5 ℃, the tempering time is 3H, each steel ball is fully tempered, the tempering stability is good, the hardness uniformity is good, the hardness dispersion is small, the hardness grain difference reaches less than 0.5HRC, the hardness batch difference reaches less than 0.8HRC, the used equipment is ZMZ803 of Suzhou Zhongmen, and the heat treatment is finished.
Example 2
The heat treatment processing technology for the high-precision long-life abnormal sound-free bearing rolling body comprises the following steps:
1) firstly, weighing a certain weight of steel balls to be treated by a self-weighing device, conveying the steel balls to a drum-type ultrasonic cleaning machine for cleaning, using an environment-friendly cleaning agent, and drying by a circulating hot air drying device; the weight of each steel ball to be treated is 6 kg; the steel balls to be processed are steel balls with the diameter below 3.969; the drying temperature is 150 +/-5 ℃, the dried steel ball is fully dried, the surface is free of moisture and foreign matter adhesion, the decarburization or recarburization of the steel ball surface caused by carbon potential fluctuation of the austenitizing furnace is avoided, and the steel ball is prevented from forming soft spots during quenching.
2) Heating the cleaned steel ball at a low temperature until the temperature for austenitizing the steel ball is 840 +/-5 ℃ and the austenitizing time is 65 min; then quenching in a nitrate bath at the salt bath temperature of 175 +/-5 ℃ for 2-3 minutes.
3) And (3) sending the quenched steel ball into a cryogenic treatment device of the strip steel ball turning and automatic timing device again for cryogenic treatment, wherein the cryogenic temperature is 150 +/-5 ℃ and the time is 2H.
4) The steel ball is firstly returned to the room temperature after the subzero treatment and then is tempered, and the tempering is carried out in time after the steel ball is returned to the room temperature and is controlled within 45 minutes; performing primary tempering in equipment with a circulating air medium at the temperature of 140 +/-5 ℃ for 3H; the equipment model used was the RJ8000x3000x250D temper equipment from the eastern garden electric company in the suzhou industrial park.
5) Cleaning the steel ball after the tempering treatment by using a high-pressure type spraying crawler belt type cleaning machine, and removing the residual nitrate on the surface of the steel ball by using an environment-friendly cleaning agent; the equipment model used was a FB95x95x26-5 track type cleaning apparatus from Thangyajie.
6) The high-temperature tempering temperature of the drum-type circulating air high-temperature tempering equipment for moving the steel balls in the furnace is 170 +/-5 ℃, the tempering time is 3H, each steel ball is fully tempered, the tempering stability is good, the hardness uniformity is good, the hardness dispersion is small, the hardness grain difference reaches less than 0.5HRC, the hardness batch difference reaches less than 0.8HRC, the used equipment is ZMZ803 of Suzhou Zhongmen, and the heat treatment is finished.
Product inspection data, national bearing quality Du inspection center/Luoyang bearing research institute inspection and detection Limited company carries out detection report, report number (2020) WT015, inspection and judgment basis to the product of the invention: GB/T308.1-2013 rolling bearing ball part 1 steel ball, JB/T8923-; the crushing load (kN) is between 11.9 and 12.6, and the far exceeding standard is more than or equal to 8.43; the martensite structure is 2, located between the standards; the working surface is not damaged after acid cleaning; the roughness (mum) of the working surface is 0.003 and far beyond the standard is less than or equal to 0.014; the roundness (mum) is 0.02-0.03, and far out standard is less than or equal to 0.13.
Claims (4)
1. The heat treatment processing technology of the bearing rolling body with high precision and long service life and no abnormal sound is characterized by comprising the following steps,
1) firstly, weighing a certain weight of steel balls to be treated by a self-weighing device, conveying the steel balls to a drum-type ultrasonic cleaning machine for cleaning, using an environment-friendly cleaning agent, and drying by a circulating hot air drying device; the drying temperature is 150 +/-5 ℃;
2) heating the cleaned steel ball at a low temperature until the temperature for austenitizing the steel ball is 840 +/-5 ℃ and the austenitizing time is 65 min; then quenching in a salt bath at the salt bath temperature of 175 +/-5 ℃ for 3-8 minutes;
3) sending the quenched steel ball into a cryogenic treatment device of a strip steel ball turning and automatic timing device again for cryogenic treatment, wherein the cryogenic temperature is 150 +/-5 ℃ and the time is 2H;
4) electrically heating the steel ball subjected to deep cooling to room temperature, then tempering, and performing primary tempering in equipment with a circulating air medium at the temperature of 140 +/-5 ℃ for 3H;
5) cleaning the steel ball after the tempering treatment by using a high-pressure type spraying crawler belt type cleaning machine, and removing the residual nitrate on the surface of the steel ball by using an environment-friendly cleaning agent;
6) the high-temperature tempering temperature of the drum-type circulating air high-temperature tempering equipment for moving the steel balls in the furnace is 170 +/-5 ℃, the tempering time is 3H, the steel balls are naturally cooled to room temperature after being tempered, each steel ball is fully tempered, the tempering stability is good, the hardness uniformity is good, the hardness dispersion difference is small, the hardness grain difference reaches less than 0.5HRC, the hardness batch difference reaches less than 0.8HRC, and the heat treatment is finished.
2. The heat treatment process for the rolling bodies of high-precision long-life noiseless bearings according to claim 1, wherein the weight of steel balls to be treated in step 1) is 6kg per conveying.
3. The heat treatment process for the rolling bodies of the high-precision long-life noiseless bearing as claimed in claim 1, wherein the steel balls to be treated are steel balls with the diameter of 3.969 or less.
4. The heat treatment process for the high-precision long-life abnormal-sound-free bearing rolling body as claimed in claim 1, wherein the steel ball can be tempered after being subjected to deep cooling treatment in the step 4) after being returned to room temperature, and the tempering is carried out in time after being returned to the room temperature and is controlled within 45 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011417148.7A CN112609063B (en) | 2020-12-07 | 2020-12-07 | Heat treatment processing technology for high-precision long-life noiseless bearing rolling body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011417148.7A CN112609063B (en) | 2020-12-07 | 2020-12-07 | Heat treatment processing technology for high-precision long-life noiseless bearing rolling body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112609063A true CN112609063A (en) | 2021-04-06 |
| CN112609063B CN112609063B (en) | 2022-11-01 |
Family
ID=75229130
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011417148.7A Active CN112609063B (en) | 2020-12-07 | 2020-12-07 | Heat treatment processing technology for high-precision long-life noiseless bearing rolling body |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112609063B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113481464A (en) * | 2021-06-22 | 2021-10-08 | 江苏力星通用钢球股份有限公司 | High-precision long-life rolling body heat treatment carburizing process |
| CN114310494A (en) * | 2021-12-22 | 2022-04-12 | 中国科学院金属研究所 | Steel bearing ring and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85109155A (en) * | 1985-12-19 | 1987-06-24 | 大连海运学院 | Multiple strengthening technique for bearing steel workpiece |
| CN102534133A (en) * | 2010-12-16 | 2012-07-04 | 张莹 | Heat treatment process for bearing steel |
| CN102758073A (en) * | 2012-07-18 | 2012-10-31 | 浙江天马轴承股份有限公司 | Heat treatment method of bearing |
| CN104372148A (en) * | 2014-11-06 | 2015-02-25 | 无锡市百顺机械厂 | Heat treatment process of bearing steel |
| CN105886745A (en) * | 2016-06-05 | 2016-08-24 | 无锡市飞云球业有限公司 | Heat treatment technology for long-life bearing steel ball |
-
2020
- 2020-12-07 CN CN202011417148.7A patent/CN112609063B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85109155A (en) * | 1985-12-19 | 1987-06-24 | 大连海运学院 | Multiple strengthening technique for bearing steel workpiece |
| CN102534133A (en) * | 2010-12-16 | 2012-07-04 | 张莹 | Heat treatment process for bearing steel |
| CN102758073A (en) * | 2012-07-18 | 2012-10-31 | 浙江天马轴承股份有限公司 | Heat treatment method of bearing |
| CN104372148A (en) * | 2014-11-06 | 2015-02-25 | 无锡市百顺机械厂 | Heat treatment process of bearing steel |
| CN105886745A (en) * | 2016-06-05 | 2016-08-24 | 无锡市飞云球业有限公司 | Heat treatment technology for long-life bearing steel ball |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113481464A (en) * | 2021-06-22 | 2021-10-08 | 江苏力星通用钢球股份有限公司 | High-precision long-life rolling body heat treatment carburizing process |
| CN114310494A (en) * | 2021-12-22 | 2022-04-12 | 中国科学院金属研究所 | Steel bearing ring and preparation method thereof |
| CN114310494B (en) * | 2021-12-22 | 2023-12-08 | 中国科学院金属研究所 | Steel bearing ring and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112609063B (en) | 2022-11-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107201524B (en) | Laser strengthening processing forming method for surface of rotary wheel | |
| CN112609063B (en) | Heat treatment processing technology for high-precision long-life noiseless bearing rolling body | |
| CN109266826B (en) | Production method of low-carbide net-shaped grade GCr15 bearing round steel | |
| CN101597680B (en) | Process for quenching-distribution heat treatment on 60Si2CrVA steel spring for trains | |
| CN107282839A (en) | A kind of forging technology of forging | |
| CN103352108A (en) | H13 molten steel cold and hot treatment process | |
| CN108070703A (en) | A kind of bearing heat treatment process | |
| CN107263028A (en) | A kind of processing technology of Novel shaft class part machinery | |
| CN108531920A (en) | A kind of pre-treating technology of hydraulic plunger workpiece | |
| CN113481464B (en) | High-precision long-life rolling body heat treatment carburizing process | |
| CN111593190A (en) | Heat treatment process of alloy spring steel | |
| CN101654723A (en) | Method for eliminating cracks on surface of bearing axle by induction heating | |
| CN101513654B (en) | Straightening roller for cold rolling of wide and thick plate and manufacturing method thereof | |
| CN109468451B (en) | Heat treatment method of 55NiCrMoV7 roller way roller | |
| CN107514425A (en) | The preparation method of bearing ball | |
| CN109128708A (en) | A kind of thrust wheel wheel shaft processing method | |
| CN109262203B (en) | Preparation method of impact-resistant alloy tool steel ball | |
| CN109079441B (en) | Production process of high-quality steel ball for bearing | |
| CN104946859A (en) | Heat treatment hardening and tempering technology for hexagonal flange nut | |
| CN109136475A (en) | Improve the method for closing door bolt spring fatigue life | |
| CN108559830A (en) | A kind of system that hydraulic plunger workpiece is heat-treated | |
| CN114150138B (en) | Method for processing differential heating interruption of large forged steel supporting roller | |
| CN113083937B (en) | Production process of bearing steel pipe for cold-rolled expanded bearing | |
| CN114058829B (en) | Improved heat treatment process of bearing outer ring | |
| CN110760664B (en) | Repair heat treatment process for improving performance of initially rolled graphite steel roller |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |