CN110923408A - Surface heat treatment process for small-size roller - Google Patents
Surface heat treatment process for small-size roller Download PDFInfo
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- CN110923408A CN110923408A CN201911118775.8A CN201911118775A CN110923408A CN 110923408 A CN110923408 A CN 110923408A CN 201911118775 A CN201911118775 A CN 201911118775A CN 110923408 A CN110923408 A CN 110923408A
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- quenching
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- 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
- C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
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- 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
- C21D1/62—Quenching devices
- C21D1/667—Quenching devices for spray quenching
-
- 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
- C21D9/38—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for roll bodies
-
- 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
- Y02P10/25—Process efficiency
Abstract
The invention relates to a surface heat treatment process of a small-size roller based on 250HZ quenching equipment, which can improve the surface quenching quality of the small-size roller.A power frequency induction coil of 50HZ on a double-frequency quenching machine tool is removed by transforming 50/250HZ double-frequency quenching equipment to become single intermediate frequency quenching equipment with the frequency of 250 HZ; in the single medium-frequency quenching process, the medium-frequency induction coil is fixed, quenching is carried out in a workpiece rotation descending mode, the preheating temperature is set to be 200 +/-10 ℃, the descending speed of the workpiece is 1.1-1.4mm/s, and the rotating speed of the workpiece is 40 r/min; after quenching, the cooling mode is water spray cooling and continuous cooling of a quenching bath, and finally tempering is carried out at a tempering temperature of 140 +/-10 ℃ to finish the surface heat treatment process, so that the characteristic of an 50/250HZ double-frequency quenching machine tool is fully utilized, and the roller after quenching has good quality, uniform and stable hardness and is not easy to generate soft spots.
Description
Technical Field
The invention relates to a surface heat treatment process of a small-size roller based on 250HZ quenching equipment, which can improve the surface quenching quality of the small-size roller, and belongs to the technical field of heat treatment.
Background
In the final heat treatment surface quenching process of a small-size roller (phi 160-phi 240), a high-frequency single induction coil is usually adopted for quenching, the main operation mode is that a workpiece is fixed and rotates at a certain speed, a heating induction coil moves along the surface of the quenching roller for heating, a water spraying device is connected with the induction coil, and after heating, water is sprayed and cooled immediately, thus the surface quenching process is completed. The roller quenched by the method has poor hardness uniformity, shallow quenched layer and poor hardness stability, and cannot easily meet the technical requirements of users. 50/250HZ double frequency quenching machine tool quenchable roller diameter range is phi 300-phi 700, because the equipment is power frequency + medium frequency double induction coil heating, and the induction coil height reaches 165mm, 10 times of common high frequency quenching induction coil, when quenching small diameter roller, the heating depth is too deep because of too long heating time, the roller core reaches austenitizing temperature, thereby the roller is wholly quenched, when losing the quenching and tempering, the proper mechanical property (toughness, shock resistance, etc.) of the inner part is obtained, when in use, accidents such as breaking, roller explosion, etc. are easy to occur, and the use effect is influenced. In view of this, a double-frequency quenching machine tool needs to be modified to realize a surface heat treatment process of a single medium-frequency quenching small-specification roller (phi 160-phi 240), and the characteristics of 250HZ single medium-frequency quenching are combined, so that the effects of good uniformity of hardness of the delivery roller, satisfaction of technical requirements of a hardening layer and good hardness stability are finally achieved.
Disclosure of Invention
The invention aims to provide a surface heat treatment process of a small-specification roller based on 250HZ quenching equipment, aiming at the defects of uneven high-frequency quenching hardness, shallow hardening layer, poor hardness stability and easy failure of the roller during the final heat treatment of the small-specification roller.
The technical scheme of the invention is realized as follows: the surface heat treatment process of the small-size roller is realized by the following steps based on 250HZ quenching equipment:
step 1), a single intermediate frequency surface heat treatment process is realized by modifying 50/250HZ double-frequency quenching equipment, specifically, a 50HZ power frequency induction coil on a double-frequency quenching machine tool is removed, and the single intermediate frequency quenching equipment with the frequency of 250HZ is changed;
step 2), in the single medium-frequency quenching process, fixing the medium-frequency induction coil, quenching in a workpiece rotating and descending manner, setting the preheating temperature to be 200 +/-10 ℃, the descending speed of the workpiece to be 1.1-1.4mm/s, and the rotating speed of the workpiece to be 40 r/min;
step 3), after quenching, the cooling mode is water spray cooling and continuous cooling of the quenching bath, the continuous cooling time for continuous cooling in the quenching bath is 30 +/-10 min, and then the quenching process is finished;
and 4) finally, tempering at a tempering temperature of 140 +/-10 ℃ according to the hardness requirement of the roller body to finish the surface heat treatment process.
Further, after the step 4, a step 5) of equally dividing the workpiece subjected to the surface heat treatment into 4 buses, detecting the hardness of the roller body and verifying the hardness value and the hardness uniformity is also provided; the hardness value of the roller after quenching is required to be between 90 and 95HSD, the hardness uniformity is higher than 3HSD of common surface quenching and within 1.5HSD, the depth of a hardening layer is higher than 2 to 6mm of high-frequency surface quenching and more than 12mm, and the technical condition that the hardness requirement is more than 10mm when the roller is used is achieved.
Further, the diameter of the workpiece of the small-size roller is between 160 mm and 240 mm.
Further, the height of intermediate frequency induction coil is 165 mm.
Further, a water spraying ring is arranged below the medium-frequency induction coil.
The invention has the following advantages:
1) the characteristic of an 50/250HZ double-frequency quenching machine tool can be utilized and transformed, the method is suitable for quenching small-specification rollers (phi 160-phi 240), and the full utilization of equipment is realized;
2) the quenched roller has good quality, the uniformity of hardness is within 1.5HSD, is higher than 3HSD of surface quenching, has good stability of hardness, is not easy to generate soft spots, and has the situation that the hardness is rapidly reduced in the using process, and the like, the depth of a hardening layer is more than 12mm and is higher than 2-6mm of the high-frequency surface quenching, and the technical requirements of the roller in use are fully met.
Drawings
FIG. 1 is a schematic diagram of a modified 250HZ single intermediate frequency structure of the present invention.
FIG. 2 is a hardness distribution diagram of the modified 250HZ single medium frequency quenching and high frequency quenching at different depths.
FIG. 3 is a comparison graph of surface hardness uniformity detection of single medium frequency quenching and high frequency quenching of 250HZ after modification.
The labels in the figures are: 1. phi 225 roller; 2. a medium frequency induction coil; 3. a water spray ring; 4. a quenching bath.
Detailed Description
As shown in figure 1, the surface heat treatment process of the small-size roller is realized by the following steps based on a 250HZ quenching device:
step 1), a single intermediate frequency surface heat treatment process is realized by modifying 50/250HZ double-frequency quenching equipment, specifically, a power frequency induction coil of 50HZ on a double-frequency quenching machine tool is removed, a middle frequency induction coil 2 of 250HZ is reserved, and the single intermediate frequency quenching equipment with the frequency of 250HZ is changed; the single medium-frequency surface heat treatment process is realized by modifying 50/250HZ double-frequency quenching equipment, the surface heat treatment process of a phi 225 roller 1 is realized by using 50/250HZ double-frequency quenching equipment, the quenching process is completed by adjusting process parameters and combining with equipment characteristics, and the improvement of the quality of a small-sized roller, namely the improvement of the hardness uniformity and the depth of a hardened layer is realized; the medium-frequency induction coil 2 with the medium-frequency of 250HZ is selected, the penetrating power during heating is larger than the high frequency, the temperature of the roller body of the roller with a certain depth (more than 10 mm) reaching austenitizing can be ensured, and the depth of a hardening layer is effectively ensured; the single intermediate frequency quenching process with the frequency of 250HZ is selected, and the height of the intermediate frequency induction coil 2 with the frequency of 250HZ is 165 mm; and a water spraying ring 3 is arranged below the intermediate frequency induction coil.
Step 2), in the single medium-frequency quenching process, fixing the medium-frequency induction coil, quenching in a workpiece rotating and descending manner, setting the preheating temperature to be 200 +/-10 ℃, the descending speed of the workpiece to be 1.1-1.4mm/s, and the rotating speed of the workpiece to be 40 r/min;
step 3), after quenching, the cooling mode is water spray cooling and continuous cooling of the quenching bath, the continuous cooling time for continuous cooling in the quenching bath 4 is 30 +/-10 min, and then the quenching process is finished;
and 4) finally, tempering at a tempering temperature of 140 +/-10 ℃ according to the hardness requirement of the roller body to finish the surface heat treatment process.
After the step 4, a step 5) of equally dividing the workpiece subjected to the surface heat treatment into 4 buses, detecting the hardness of the roller body and verifying the hardness value and the hardness uniformity is also arranged; the hardness value of the roller after quenching is required to be between 90 and 95HSD, the hardness uniformity is higher than 3HSD of common surface quenching and within 1.5HSD, the depth of a hardening layer is higher than 2 to 6mm of high-frequency surface quenching and more than 12mm, and the technical condition that the hardness requirement is more than 10mm when the roller is used is achieved.
The diameter of the workpiece of the small-size roller is between 160 mm and 240 mm.
Example (b): as shown in fig. 1, 2 and 3, the quenching process of the 9Cr3Mo small work roll made of phi 225 × 1150 × 2526 material was used for process result verification.
Step 1), a single intermediate frequency surface heat treatment process is realized by modifying 50/250HZ double-frequency quenching equipment, specifically, a 50HZ induction coil on a 50/250HZ double-frequency quenching machine tool is removed, a 250HZ intermediate frequency induction coil 2 is reserved, and the single intermediate frequency quenching equipment with the frequency of 250HZ is changed; the cooling water pipeline of the connected electric appliance is changed to change the equipment into single medium frequency quenching equipment without influencing the normal operation of the 250HZ induction coil;
step 2), when quenching the phi 225 roller 1, the height of an induction coil used by matching the equipment is much higher (about 10 times) than that of an induction coil of high-frequency quenching equipment, so that the heating time of the roller is too long, the roller core part is easily heated completely, the preheating temperature is selected to be 200 +/-10 ℃ for preventing the temperature from rising too much during quenching heating (lower than the conventional 220 ℃ and 350 ℃), and the core part is prevented from being too high and integrally quenched completely while small stress is generated during quenching; in the single intermediate frequency quenching process, the height of the intermediate frequency induction coil is 165mm, the intermediate frequency induction coil is fixed, a phi 292 induction coil is connected to a 250HZ transformer, and the single-side gap between a phi 225 roller 1 and an intermediate frequency induction coil 2 is 32 mm; because the height of the induction coil is larger than that of other equipment for quenching small-specification rolls, during single medium-frequency quenching, the descending speed (the conventional speed is 0.5-0.7mm/s, the current speed can be set to be 1.1-1.4 mm/s) and the rotating speed are increased to avoid the heating depth from being too deep, the limit of the descending speed of the equipment is 1.5m/s, the current descending speed is set to be 1.4m/s, the rotating speed of a workpiece is 40r/min, and surface quenching is carried out within the allowable range of the equipment; so as to reduce the contact time between the induction coil and the heating part of the roller body and avoid the influence of the overhigh temperature of the roller core part on the mechanical performance of the core part. Meanwhile, the penetration force during heating is larger than the high frequency due to the selection of the medium frequency 250HZ frequency, so that the temperature of the roller body of the roller with a certain depth (more than 10 mm) can be ensured to reach austenitizing temperature, and the depth of a hardening layer is effectively ensured; the quenching mode that the workpiece rotates and descends in the descending process can ensure the hardness uniformity (within 1.5 HSD) of the quenching roller body to the maximum extent;
step 3), after quenching the phi 225 roller 1, the cooling mode is water spray cooling and continuous cooling of a quenching bath, and a water spray ring 3 is arranged below the medium-frequency induction coil; firstly, cooling a phi 225 roller 1 by a water spray ring 3, then continuously cooling in a quenching bath for 30 +/-10 min, and then finishing the quenching process; the final cooling mode is carried out by combining water spray cooling and reservoir cooling, so that the roller cooling process is fully carried out, and the hardness stability of the roller is ensured;
and 4) finally, according to the drawing requirements (roller body hardness: 90-95 HSD), selecting proper tempering temperature (140 +/-10 ℃) for tempering, and finishing the surface heat treatment process;
and 5) uniformly dividing 4 buses for the phi 225 roller 1, detecting the hardness of the roller body, and verifying the hardness value and the hardness uniformity.
The invention realizes the surface heat treatment process of the supporting roller by using 50/250HZ dual-frequency quenching equipment, finishes the quenching process by adjusting process parameters and combining with equipment characteristics, and realizes the improvement of the quality of the small-specification roller, namely the improvement of the hardness uniformity and the depth of a hardening layer.
Claims (5)
1. A surface heat treatment process of a small-size roller is characterized by comprising the following steps: the heat treatment process is realized by the following steps based on 250HZ quenching equipment:
step 1), a single intermediate frequency surface heat treatment process is realized by modifying 50/250HZ double-frequency quenching equipment, specifically, a 50HZ power frequency induction coil on a double-frequency quenching machine tool is removed, and the single intermediate frequency quenching equipment with the frequency of 250HZ is changed;
step 2), in the single medium-frequency quenching process, fixing the medium-frequency induction coil, quenching in a workpiece rotating and descending manner, setting the preheating temperature to be 200 +/-10 ℃, the descending speed of the workpiece to be 1.1-1.4mm/s, and the rotating speed of the workpiece to be 40 r/min;
step 3), after quenching, the cooling mode is water spray cooling and continuous cooling of the quenching bath, continuous cooling is carried out in the quenching bath, the continuous cooling time is 30 +/-10 min, and then the quenching process is finished;
and 4) finally, tempering at a tempering temperature of 140 +/-10 ℃ according to the hardness requirement of the roller body to finish the surface heat treatment process.
2. The surface heat treatment process of a small-sized roll as set forth in claim 1, wherein: after the step 4, a step 5) of equally dividing the workpiece subjected to the surface heat treatment into 4 buses, detecting the hardness of the roller body and verifying the hardness value and the hardness uniformity is also arranged; the hardness value of the roller after quenching is required to be between 90 and 95HSD, the hardness uniformity is higher than 3HSD of common surface quenching and within 1.5HSD, the depth of a hardening layer is higher than 2 to 6mm of high-frequency surface quenching and more than 12mm, and the technical condition that the hardness requirement is more than 10mm when the roller is used is achieved.
3. The surface heat treatment process of a small-sized roll as set forth in claim 1, wherein: the diameter of the workpiece of the small-size roller is between 160 mm and 240 mm.
4. The surface heat treatment process of a small-sized roll as set forth in claim 1, wherein: the height of the medium-frequency induction coil is 165 mm.
5. The surface heat treatment process of a small-sized roll as set forth in claim 1, wherein: and a water spraying ring is arranged below the intermediate frequency induction coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911118775.8A CN110923408A (en) | 2019-11-15 | 2019-11-15 | Surface heat treatment process for small-size roller |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911118775.8A CN110923408A (en) | 2019-11-15 | 2019-11-15 | Surface heat treatment process for small-size roller |
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| CN110923408A true CN110923408A (en) | 2020-03-27 |
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| CN201911118775.8A Withdrawn CN110923408A (en) | 2019-11-15 | 2019-11-15 | Surface heat treatment process for small-size roller |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112522501A (en) * | 2020-12-02 | 2021-03-19 | 河南中原特钢装备制造有限公司 | Annealing process of surface quenching interrupted roller made of Cr3 or Cr5 |
| CN112708750A (en) * | 2021-01-22 | 2021-04-27 | 河北智方机械制造有限公司 | Roll surface heat treatment method of roll shell of roll squeezer |
| CN114833196A (en) * | 2022-05-23 | 2022-08-02 | 常熟科弘材料科技有限公司 | Soft point improving method for household appliance chilled substrate and household appliance chilled substrate |
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| CN103320601A (en) * | 2013-06-25 | 2013-09-25 | 宝钢轧辊科技有限责任公司 | Surface quenching method of hot straightening roll |
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2019
- 2019-11-15 CN CN201911118775.8A patent/CN110923408A/en not_active Withdrawn
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| CN202744600U (en) * | 2012-08-09 | 2013-02-20 | 耿震宇 | Large multi-functional roll quenching machine |
| CN103320601A (en) * | 2013-06-25 | 2013-09-25 | 宝钢轧辊科技有限责任公司 | Surface quenching method of hot straightening roll |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112522501A (en) * | 2020-12-02 | 2021-03-19 | 河南中原特钢装备制造有限公司 | Annealing process of surface quenching interrupted roller made of Cr3 or Cr5 |
| CN112522501B (en) * | 2020-12-02 | 2022-08-02 | 河南中原特钢装备制造有限公司 | Annealing process of surface quenching interrupted roller made of Cr3 or Cr5 |
| CN112708750A (en) * | 2021-01-22 | 2021-04-27 | 河北智方机械制造有限公司 | Roll surface heat treatment method of roll shell of roll squeezer |
| CN114833196A (en) * | 2022-05-23 | 2022-08-02 | 常熟科弘材料科技有限公司 | Soft point improving method for household appliance chilled substrate and household appliance chilled substrate |
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