WO2007102306A1 - Procede de trempe haute frequence, appareil de trempe haute frequence et produit d'une trempe haute frequence - Google Patents

Procede de trempe haute frequence, appareil de trempe haute frequence et produit d'une trempe haute frequence Download PDF

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Publication number
WO2007102306A1
WO2007102306A1 PCT/JP2007/053033 JP2007053033W WO2007102306A1 WO 2007102306 A1 WO2007102306 A1 WO 2007102306A1 JP 2007053033 W JP2007053033 W JP 2007053033W WO 2007102306 A1 WO2007102306 A1 WO 2007102306A1
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WIPO (PCT)
Prior art keywords
temperature
quenching
tempering
workpiece
heating
Prior art date
Application number
PCT/JP2007/053033
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English (en)
Japanese (ja)
Inventor
Takumi Fujita
Nobuyuki Suzuki
Original Assignee
Ntn Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP2006064463A external-priority patent/JP2007239044A/ja
Priority claimed from JP2006064453A external-priority patent/JP2007239043A/ja
Priority claimed from JP2006064249A external-priority patent/JP2007239039A/ja
Application filed by Ntn Corporation filed Critical Ntn Corporation
Publication of WO2007102306A1 publication Critical patent/WO2007102306A1/fr

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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
    • 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
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/34—Methods of heating
    • C21D1/42—Induction heating
    • 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
    • C21D1/68—Temporary coatings or embedding materials applied before or during heat treatment
    • C21D1/70—Temporary coatings or embedding materials applied before or during heat treatment while heating or 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
    • C21D11/00—Process control or regulation for heat treatments
    • 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
    • C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races
    • 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

Definitions

  • the present invention relates to an induction hardening method, an induction hardening apparatus, and an induction hardening product, and more specifically, an induction hardening method and induction hardening in which an object to be processed is quenched by induction heating. Equipment and induction-hardened products that have been quenched by induction heating.
  • Induction hardening is a heat treatment method in which an object to be processed set adjacent to the induction coil is induction-heated by flowing a high-frequency current through the induction coil to quench the object to be processed.
  • This induction hardening is a work environment and is able to efficiently process small lots of products in a short time compared to carburizing quenching and bright heat treatment, which are generally adopted as heat treatment methods for steel. This is advantageous. Therefore, many studies have been made on the induction hardening method and induction hardening apparatus for the purpose of controlling the hardness of the workpiece and improving the efficiency of heat treatment, and various proposals have been made (Japanese Patent Laid-Open No. 2004-315851). (Patent Document 1) and JP 2004-225081 (Patent Document 2)).
  • Patent Document 1 JP 2004-315851 A
  • Patent Document 2 JP 2004-225081 A
  • the induction hardening unlike the quenching method in which the workpiece is heated via the atmosphere in the furnace like heating in a general atmospheric furnace, the workpiece is directly heated by induction heating. The Therefore, in order to measure the temperature of the workpiece, it is necessary to directly measure the temperature of the workpiece. However, it is difficult to install a contact-type thermometer in the induction hardening apparatus, which often has a drive mechanism for rotating the object to be processed in order to heat the object to be processed uniformly. There are many cases.
  • the object of the present invention is to enable temperature control and to easily determine the conditions for heat treatment, so that past production results are less accumulated, or an inexperienced manufacturer is required.
  • induction hardening can be performed easily and efficiently, and heat treatment quality such as desired hardness and retained austenite amount can be imparted to a wide range of workpieces.
  • an induction hardening apparatus for performing the induction hardening method is another object of the present invention.
  • Another object of the present invention is to provide an induction-hardened product with reduced production costs and stable quality.
  • the induction hardening method according to the present invention is an induction hardening method in which the whole object to be processed is heated and hardened by induction heating, and is a temperature control method in which the temperature of the object to be processed is adjusted. And a quenching control step in which the timing at which the heated workpiece is to be cooled is determined and the workpiece is cooled. In the temperature control process, the temperature of the workpiece is measured. Temperature control process and temperature control process that outputs temperature control signals for controlling the heating state of the workpiece based on the temperature information measured in the temperature control process. And a heating step in which the workpiece is heated by high frequency heating based on the temperature control signal.
  • the quenching control process includes a high-temperature portion in the workpiece to be treated with a high-temperature portion where the temperature rise due to high-frequency heating is larger than the inside of the workpiece, and a temperature rise due to high-frequency heating within the workpiece.
  • the heating time is adjusted based on the measured temperature information in the quenching temperature measurement process in which the temperature of the lower temperature part, which is a smaller surface area, is measured, and the quenching temperature measurement process.
  • the cooling timing adjustment process in which the timing at which the workpiece is to be cooled is determined and a cooling start signal is output, and the workpiece is quenched and hardened by cooling the workpiece based on the cooling start signal. Cooling process.
  • the temperature history conditions including the temperature history including the temperature and the heating time in the high temperature portion are less than the predetermined upper limit value of the desired retained austenite amount.
  • the heating time is adjusted so that the temperature history including the temperature in the low temperature part and the heating time satisfies the condition of the temperature history at which the hardness exceeding the lower limit of the desired hardness obtained in advance is satisfied.
  • a start signal is output.
  • the transition of power output (power output pattern), which also includes power and time parameters as heat treatment conditions, is determined based on past heat treatment results and operator experience. (Power control).
  • the heat treatment conditions are determined by actually heat-treating the sample of the object to be processed while changing the power and time in consideration of the shape, size, material, etc. of the object to be processed. Therefore, experience and labor are required to determine the heat treatment conditions.
  • the temperature control step and the quench control step In contrast, in the induction hardening method of the present invention, the temperature control step and the quench control step Thus, heating of the workpiece is controlled using temperature and time as parameters (temperature control). For this reason, it is possible to accurately grasp the heating history of the object to be processed, and after quenching it after giving the necessary heating history to the object to be processed, quenching can be performed.
  • the composition of the steel constituting the workpiece is determined, the hardness of the workpiece, the amount of retained austenite of the steel constituting the workpiece, and the heat treatment quality such as the microstructure, the heating temperature and time Determined by. Therefore, it is relatively easy for an operator who performs heat treatment to determine the approximate heating time and temperature conditions necessary for imparting desired heat treatment quality to the workpiece as temporary heat treatment conditions.
  • the temperature history condition in the high temperature portion is a temperature history condition that provides a residual austenite amount that is less than or equal to a predetermined upper limit value of the retained austenite amount.
  • the heating history is adjusted so as to satisfy the temperature history condition in which the temperature history in the low temperature part is higher than the predetermined lower limit of the desired hardness, and a cooling start signal is output.
  • the object to be processed is not heated completely and uniformly. At the part where the amount of magnetic flux entering the induction coil is large, the temperature is high, and conversely, the magnetic flux far from the induction coil. The temperature is lowered at the site where the intrusion amount is small.
  • the lower limit value of the hardness required to ensure the strength and rigidity required for the object to be processed is determined.
  • the upper limit of the amount of retained austenite necessary to ensure the dimensional stability required for the workpiece small change in shape over time
  • the hardness of the workpiece is affected by the amount of carbon that is dissolved in the steel substrate during quenching, so basically the heating temperature before cooling in quenching is high and the heating time is high. The longer the is, the larger the solid solution of carbon and the higher the hardness. On the other hand, the amount of retained austenite is also affected by the amount of carbon dissolved in the steel substrate during quenching. The higher the heating temperature before cooling in quenching and the longer the heating time, the greater the amount of carbon dissolved. , M
  • the amount of retained austenite increases. Therefore, the part where the amount of magnetic flux penetrates is low and the temperature is low (low temperature part).
  • the part is heated at the temperature and time required to obtain the hardness exceeding the 1S lower limit, and the part where the magnetic flux penetrates much and the temperature is high. (High temperature part) is less than upper limit
  • the lower limit value of the hardness at the part heated to a temperature between the high temperature part and the low temperature part by being heated below the temperature and time necessary to obtain the retained austenite amount and being quenched. And the upper limit of the amount of retained austenite is satisfied.
  • the detailed heat treatment conditions are determined based on the conditions of the desired hardness and the amount of retained austenite. Since quenching is performed, the desired hardness and the amount of retained austenite can be easily imparted to the workpiece.
  • the high temperature part and the low temperature part are preferably the part where the penetration of the magnetic flux is the most and the part where the penetration is the smallest.
  • the part has the highest temperature and the part having the lowest temperature.
  • the temperature rises at the protrusions and corners.
  • the induction hardening method of the present invention it is possible to control the temperature, and it is possible to easily determine the conditions of the heat treatment, so that the accumulation of past production results is small. Even when inexperienced workers perform heat treatment work, they can be easily and efficiently carried out, and heat treatment quality such as desired hardness and residual austenite content can be given to a wide range of workpieces. It is possible to provide an induction hardening method that can be performed.
  • An induction hardening apparatus is an induction hardening apparatus used in the above induction hardening method for heating and hardening an entire object to be processed by induction heating.
  • the temperature control device is connected to a temperature control temperature measuring device that acquires temperature data of the object to be processed and outputs temperature information based on the temperature data of the object to be processed, and a temperature control temperature measuring device.
  • the temperature control device outputs a temperature control signal for controlling the heating state of the workpiece based on the temperature information of the temperature control device for temperature control, and is connected to the temperature control device.
  • a heating device for heating the object to be processed by high-frequency heating based on the temperature control signal.
  • a quenching control device acquires temperature data of a high temperature portion and a low temperature portion of a workpiece, and outputs a temperature information based on the temperature data of the workpiece, and a quenching temperature measuring device.
  • Cooling timing adjustment that is connected to the temperature measuring device, adjusts the heating time based on the temperature information of the quenching temperature measuring device, determines the timing at which the workpiece should be cooled, and outputs a cooling start signal And a cooling device connected to the cooling timing adjusting device and quenching and hardening the workpiece by cooling the workpiece based on the cooling start signal.
  • the induction hardening apparatus of the present invention capable of heat-treating an object to be processed by the above-described induction hardening method of the present invention, temperature control can be performed and conditions for heat treatment can be easily set. By making this possible, quenching can be carried out easily and efficiently even when there is little accumulation of past production results, or even when an inexperienced V ⁇ operator performs heat treatment work. Furthermore, according to the induction hardening apparatus of the present invention, heat treatment quality such as desired hardness and retained austenite amount can be imparted to a wide range of workpieces.
  • the induction-hardened product according to the present invention is characterized by being heat-treated by the above-described induction-quenching method of the present invention.
  • the temperature can be controlled and the conditions for the heat treatment can be easily determined, so that the quenching is easily and efficiently performed and the workpiece is processed. Since the quenching is performed by the induction hardening method of the present invention capable of imparting desired heat treatment quality to a wide range of products, the manufacturing cost is suppressed and the induction hardened product with stable quality is obtained. Can be provided.
  • the induction-hardened product of the present invention can be applied to, for example, steel parts such as rolling bearing raceways and rolling elements.
  • the induction heat treatment equipment is an induction heat treatment equipment for heat-treating an object to be processed by induction heating, and includes an apparatus for transferring the object to be processed and an apparatus for transferring the object. It is equipped with an induction hardening apparatus that heats and hardens the conveyed workpiece by induction heating.
  • the induction hardening apparatus includes a quenching temperature control device for adjusting the temperature of the workpiece and a quenching timing control device for adjusting the timing at which the heated workpiece is cooled.
  • the induction hardening device is a quenching temperature control device that supplies power to the quenching induction coil to heat the workpiece.
  • the quenching process includes the quenching output transition data, which is the transitional data of the power output that is applied, and the quenching timing data for identifying the timing at which the workpiece is cooled in the quenching timing control device.
  • a quenching storage device for storing data is included.
  • the quenching temperature control device acquires the temperature data of the object to be processed, and outputs a temperature information based on the temperature data of the object to be processed, and a quenching temperature control device for quenching temperature control.
  • a quenching temperature control device that outputs a quenching temperature control signal for controlling the heating state of the workpiece based on the temperature information of the quenching temperature control temperature measuring device force.
  • Quenching heating including a quenching power supply and a quenching induction coil, connected to the quenching temperature control device, and heats the workpiece by induction heating based on the quenching temperature control signal from the quenching temperature control device Device.
  • the quenching timing control device acquires the temperature data of the workpiece and outputs the temperature information based on the workpiece temperature data, and the quenching timing control temperature measurement device. Quenching that is connected to the equipment, adjusts the heating time based on temperature information from the quenching timing control temperature measuring device, determines the timing at which the workpiece should be cooled, and outputs a quenching cooling start signal. There is a timing adjustment device and a quenching cooling device that is connected to the quenching timing adjustment device and quenches and hardens the workpiece by cooling the workpiece based on the quenching cooling start signal. is doing.
  • the transition of power output (power output pattern), which also includes power and time parameters as heat treatment conditions, is determined based on past heat treatment results and operator experience. (Power control).
  • the heat treatment conditions are determined by actually heat-treating the sample of the object to be processed while changing the power and time in consideration of the shape and material of the object to be processed. Therefore, experience and labor are required to determine the heat treatment conditions.
  • the heating of the workpiece is controlled by the induction temperature control device and the induction timing control device using the temperature and time as parameters ( Temperature control). Therefore, accurately grasp the heating history of the workpiece Quenching can be performed by giving a necessary heating history to the object to be processed and then rapidly cooling it.
  • the heat treatment quality such as the hardness of the workpiece, the micro yarns and weaves of the steel constituting the workpiece and the amount of retained austenite is determined by the heating temperature. And can be easily controlled by time. For this reason, the worker who performs the heat treatment should determine the heating time and temperature conditions necessary for imparting the desired heat treatment quality to the workpiece as the heat treatment conditions! And labor is greatly reduced. As a result, it is possible to easily perform high-frequency heat treatment even when there is little accumulation of past production results, or even when an inexperienced worker performs heat treatment work.
  • the induction hardening apparatus stores the hardening output transition data and the quenching cooling timing data as the quenching process data. Is included.
  • the heat treatment conditions for performing the same quenching and curing process performed by the temperature control by the power control are stored in the quenching storage device. For this reason, after confirming the appropriateness of the heat treatment conditions of induction hardening performed under temperature and time conditions, in the actual mass production process, high-frequency power control is performed by power control that is easy to control according to the stored heat treatment conditions. Heat treatment can be performed.
  • the high-frequency heat treatment equipment of the present invention includes a transfer device for transferring an object to be processed.
  • a transfer device for transferring an object to be processed.
  • the high-frequency heat treatment equipment of the present invention it is possible to control the temperature, and it is possible to easily determine the conditions for the heat treatment, so that the past production results are less accumulated.
  • the above-described temperature measuring device for quenching temperature control avoids an excessive amount of retained austenite due to excessive heating of the object to be processed, so that the temperature of the object to be processed is high. It is preferable to be able to measure the temperature of a part near the induction coil, for example, the part where the magnetic flux intrudes most. Further, the above-described temperature measuring device for quenching timing control avoids insufficient heating of the workpiece before quenching, so that a portion of the workpiece to be cooled, for example, induction coil force far away magnetic flux It is preferable that the temperature of the part where the intrusion is the smallest is measurable.
  • the temperature measuring device for quenching temperature control and the temperature measuring device for quenching timing control can use, for example, a radiation thermometer. If possible, a contact-type thermometer such as a thermocouple on the layout of the device. Even so.
  • the induction heat treatment equipment further includes an induction tempering apparatus connected to an induction hardening apparatus and tempering the object to be hardened and hardened in the induction hardening apparatus by heating with induction heating.
  • the induction tempering device includes a tempering temperature control device for adjusting the temperature of the workpiece, and a tempering end timing control device for adjusting the timing at which the heated workpiece is cooled.
  • the induction tempering device is a tempering temperature control device, which is the tempering power data that is output to the induction coil for tempering for high-frequency heating to heat the workpiece.
  • Tempering storage device that stores output transition data for tempering and cooling timing data for tempering to identify when the workpiece is cooled in the tempering end timing control device as tempering process data Including /!
  • the tempering temperature control device acquires temperature data of the object to be processed, and outputs a temperature information based on the temperature data of the object to be processed.
  • a tempering temperature adjusting device that is connected to a temperature measuring device for outputting a tempering temperature control signal for controlling the heating state of the object to be processed based on temperature information from the temperature measuring device for tempering temperature control.
  • Tempering heating including power supply for tempering and induction coil for tempering, which is connected to the tempering temperature control device and heats the workpiece by high frequency heating based on the tempering temperature control signal from the tempering temperature control device With equipment.
  • the tempering end timing control device acquires temperature data of the object to be processed, and outputs a temperature information based on the temperature data of the object to be processed, and a temperature measuring device for tempering end timing control, and tempering end Timing control temperature measuring device connected to the timing control temperature control device for controlling the tempering end timing.
  • the tempering end timing adjusting device that outputs the tempering cooling start signal and the tempering end timing adjusting device to cool the workpiece based on the tempering cooling start signal.
  • a tempering end device for ending the tempering of the workpiece.
  • the induction hardening apparatus and the induction tempering apparatus can constitute a single production line. Therefore, it is possible to carry out the quenching and tempering process efficiently by continuously tempering the workpiece that has been quenched and hardened in the induction hardening apparatus without holding it as an in-process product.
  • the induction tempering apparatus has a configuration capable of performing heat treatment by temperature control, like the induction hardening apparatus. Therefore, it is possible to accurately grasp the heating history of the object to be processed, and after providing the necessary and sufficient heating history to the object to be processed, tempering can be performed by cooling.
  • the hardness of the most important workpiece can be easily controlled by heating temperature and time. Therefore, the operator who performs the heat treatment should determine the temperature and heating time conditions necessary to impart the desired heat treatment quality to the workpiece as the heat treatment conditions! And labor are greatly reduced.
  • the induction tempering apparatus includes a tempering storage device that stores tempering output transition data and tempering cooling timing data as tempering process data, the high frequency As with the quenching equipment, after confirming the validity of the heat treatment conditions of induction tempering performed by temperature control, in the actual mass production process, high frequency is controlled by power control that is easy to control according to the stored heat treatment conditions. Tempering can be performed.
  • the tempering end timing control temperature measuring device has a hardness that is too high due to excessive heating of the workpiece, and insufficient heating of the workpiece.
  • the temperature of the object to be processed increases in temperature, for example, the vicinity of the induction coil and the part where the magnetic flux intrudes most and the object to be processed in It is preferable to be able to measure the temperature at both of the parts where the temperature is low, for example, the part where the inductive coil force has the least penetration of the magnetic flux far away.
  • the tempering end timing control temperature measuring device includes a plurality of temperature measuring devices such as a radiation thermometer, and may be configured to measure a plurality of portions.
  • a radiation thermometer can be used as a temperature measuring device for tempering temperature control and a temperature measuring device for tempering completion timing control. A meter may be used.
  • the validity of the heat treatment conditions of induction hardening and induction tempering performed by temperature control is, for example, the hardness of the workpiece, the microstructure of the steel constituting the workpiece, the amount of retained austenite, etc. It is possible to check and confirm the material data.
  • the material data includes the temperature data measured by the temperature measuring device and the heating time in the quenching storage device and the tempering storage device when induction hardening and induction tempering are performed by temperature control. A force that can be stored and estimated based on this can be obtained by actually investigating a sample of the workpiece after heat treatment.
  • the hardness of the workpiece is obtained by cutting the workpiece after heat treatment, polishing the cut surface, and then measuring the hardness of the cut surface with a hardness meter such as a Vickers hardness meter or Rockwell hardness meter. Can.
  • a hardness meter such as a Vickers hardness meter or Rockwell hardness meter.
  • the microstructure of the steel that forms the workpiece is cut after the workpiece after heat treatment, the cut surface is polished, and then the cut surface is corroded by a corrosive liquid such as nitral (nitric alcohol solution). It can be investigated by observing with a microscope such as a microscope.
  • the amount of retained austenite can be determined by, for example, electropolishing a desired portion of the object to be treated after heat treatment, and using an X-ray diffractometer (XRD) to obtain the martensite ⁇ (211) plane and austenite ⁇ (220 It can be calculated by measuring the diffraction intensity with respect to the surface.
  • XRD X-ray diffractometer
  • the high-frequency heat treatment equipment of the present invention can be applied to heat treatment of machine parts made of steel, such as bearing rings and rolling elements, and manufactured by quench hardening.
  • the high-frequency heat treatment method is a high-frequency heat treatment method in which an object to be processed is heated and hardened by induction heating.
  • the high-frequency heat treatment method includes a surface stabilization step in which a stabilization layer having higher acid resistance than the treatment object is formed on the surface of the treatment object in a temperature range where the treatment object is heated, Stable in the stabilization process And a quench hardening step in which the object to be processed on which the conversion layer is formed is hardened by hardening.
  • a temperature control process in which the temperature of the workpiece on which the stabilization layer is formed is adjusted, and a timing at which the heated workpiece is to be cooled are determined. And a quenching control process in which the workpiece is cooled.
  • the temperature control process the temperature of the surface of the stable layer formed on the surface of the object to be processed is measured by a temperature control measurement process in which the temperature of the surface is measured by a radiation thermometer, and a temperature control temperature measurement process.
  • a temperature control process that outputs a temperature control signal for controlling the heating state of the workpiece based on the temperature information, and heating that heats the workpiece by high-frequency heating based on the temperature control signal Process.
  • the quenching control process is performed in a quenching temperature measurement process in which the temperature of the surface of the stabilization layer formed on the surface of the workpiece is measured by a radiation thermometer, and in the quenching temperature measurement process.
  • the heating time is adjusted based on the measured temperature information, the timing at which the workpiece should be cooled is determined and the cooling start signal is output, and the workpiece is processed based on the cooling start signal.
  • a cooling step in which the object to be processed is hardened by being cooled.
  • the transition of power output (power output pattern), which also includes power and time parameters as heat treatment conditions, is determined based on past heat treatment results and operator experience. (Power control).
  • the heat treatment conditions are determined by actually heat-treating the sample of the object to be processed while changing the power and time in consideration of the shape and material of the object to be processed. Therefore, experience and labor are required to determine the heat treatment conditions.
  • heating of the workpiece is controlled using the temperature and time as parameters during the quench hardening process (temperature control). Therefore, it is possible to accurately grasp the heating history of the object to be processed, and quenching can be performed by rapidly cooling after giving the necessary heating history to the object to be processed. As a result, actual In addition, it is not always necessary to investigate the quality of the workpiece, such as hardness and microstructure, obtained by heat treatment, and experience and effort are not necessarily required to determine the heat treatment conditions. Thus, according to the high-frequency heat treatment method in one aspect of the present invention, the above-described problems of high-frequency heat treatment are solved.
  • the temperature measurement accuracy of the workpiece is extremely important.
  • a contact thermometer such as a thermocouple for measuring the temperature of the object to be processed due to the layout problem of the heat treatment apparatus. Therefore, also in the high-frequency heat treatment method according to one aspect of the present invention, a radiation thermometer is employed for temperature measurement of the workpiece.
  • the atmosphere is not normally controlled, and the workpiece is heated in the atmosphere (in the air).
  • the oxidation resistance of the object to be processed is low, the surface of the object to be processed is oxidized at the initial stage of the heat treatment, and the surface state is hardly changed thereafter. Therefore, the influence of the change of the surface state on the temperature measurement accuracy is Relatively small.
  • the workpiece is made of steel containing 3% or more of chromium, for example, «Martensitic stainless steel such as JIS standard SUS440C or high-speed steel such as AISI standard M50, etc. Since it takes a relatively long time, the influence of changes in the surface condition on the temperature measurement accuracy becomes large.
  • the surface of the workpiece in the surface stabilization step, is more resistant to acid than the workpiece in the temperature range where the workpiece is heated. A highly stable stable layer is formed. For this reason, in the quench hardening process, changes in the surface state due to oxidation of the surface of the workpiece are suppressed, and a decrease in temperature measurement accuracy by the radiation thermometer is avoided. As a result, according to the high frequency heat treatment method in one aspect of the present invention, the quality of the object to be processed can be stabilized.
  • thermocontrol is possible, heat treatment conditions can be easily set, and an object to be treated is obtained. It is possible to provide a high-frequency heat treatment method capable of stabilizing the quality of the material.
  • the temperature of the workpiece in order to avoid an excessive amount of retained austenite due to excessive heating of the workpiece, the temperature of the workpiece is not reduced. It is preferable to measure the temperature at a site where the magnetic flux increases most, for example, a region where the magnetic flux intrudes most frequently.
  • the portion of the workpiece to be cooled for example, the induction coil force is far away from the magnetic flux. It is preferred that the temperature of the site with the least amount of intrusion be measured.
  • a high-frequency heat treatment method is a high-frequency heat treatment method in which an object to be treated is heated and hardened by high-frequency heating.
  • the high-frequency heat treatment method includes a data acquisition process, a storage process, a confirmation process, and a mass production process.
  • process data is acquired by heating and hardening the sample of the workpiece.
  • the memory process in order to identify the transition data of the power output output to the induction coil and the cooling power of the sample of the object to be processed in order to heat the sample of the object to be processed in the data acquisition process Are stored as process data.
  • the confirmation process the validity of the transition data of the power output and the cooling timing data is confirmed based on the material data of the workpiece that has been quenched and hardened in the data acquisition process.
  • the workpiece is quenched and hardened according to the transition data of the power output and the cooling timing data that are stored in the storage process and validated in the confirmation process.
  • the quench hardening in the data acquisition process is performed by the high frequency heat treatment method in one aspect of the present invention.
  • a radiation thermometer is employed for temperature measurement of an object to be processed. Then, by performing the surface stabilization process, the influence of disturbance on the temperature measurement accuracy is suppressed. However, for example, if dirt or water droplets adhere to the lens of the radiation thermometer, the measured temperature may contain an error, and it is preferable to take further measures against disturbance.
  • the data acquisition step is performed.
  • a storage process is provided for storing process data such as temperature measurement data, and the stored process After a confirmation process to confirm the validity of the data, the mass production process is heat-treated based on the process data whose validity is guaranteed.
  • temperature control can be performed, heat treatment conditions can be easily set, and the quality of the workpiece can be further stabilized.
  • a high-frequency heat treatment method can be provided.
  • the material data to be investigated in order to confirm the validity of the power output transition data and the cooling timing data are, for example, the hardness of the workpiece, and the microscopic value of the steel constituting the workpiece. Force, amount of retained austenite, etc. Can be one or more material data selected.
  • the material data is stored in the storage process as temperature data measured in the temperature acquisition process and temperature measurement process for quenching in the data acquisition process. Although it can be estimated based on the stored cooling timing data, actually investigate and obtain a sample of the workpiece after heat treatment.
  • the hardness of the workpiece is obtained by cutting the workpiece after the heat treatment, polishing the cut surface, and then measuring the hardness of the cut surface with a hardness meter such as a Vickers hardness meter or a Rockwell hardness meter. Can.
  • a hardness meter such as a Vickers hardness meter or a Rockwell hardness meter.
  • the microstructure of the steel that forms the workpiece is cut after the workpiece after heat treatment, the cut surface is polished, and then the cut surface is corroded by a corrosive liquid such as nitral (nitric alcohol solution). It can be investigated by observing with a microscope such as a microscope.
  • the amount of retained austenite can be determined by, for example, electropolishing a desired portion of the workpiece after heat treatment and using an X-ray diffractometer (XRD) to obtain martensite ⁇ (211) surface and austenite ⁇ (220) surface. It can be calculated by measuring the diffraction intensity.
  • XRD X-ray diffractometer
  • a high frequency heat treatment method is a high frequency heat treatment method in which an object to be treated is heated and tempered by high frequency heating.
  • the high-frequency heat treatment method includes a surface stabilization process in which a stable layer having higher acid resistance than the object to be processed is formed on the surface of the object to be processed, and a stable layer is formed in the surface stabilization process.
  • a tempering step in which the processed object is heated and tempered.
  • the tempering process is a temperature at which the temperature of the workpiece is adjusted.
  • a tempering control step in which the timing at which the heating of the workpiece is to be finished is determined and the workpiece is cooled.
  • the temperature of the surface of the stabilization layer formed on the surface of the object to be processed is measured in a temperature control temperature measurement process in which the temperature is measured with a radiation thermometer, and the temperature control temperature measurement process.
  • a temperature adjusting process for outputting a temperature control signal for controlling the heating state of the object to be processed based on the temperature information, and a heating process for heating the object to be processed by high frequency heating based on the temperature control signal And have.
  • the tempering control process consists of a tempering temperature measurement process in which the temperature of the surface of the stabilization layer formed on the surface of the workpiece is measured by a radiation thermometer, and a temperature measured in the tempering temperature measurement process. The heating time is adjusted based on the above information, the timing for cooling the workpiece is determined and the cooling start signal is output, and the workpiece is cooled based on the cooling start signal. And a cooling step in which the tempering of the object to be processed is completed.
  • heat treatment by temperature control is employed in the tempering step. Therefore, similarly to the high-frequency heat treatment method in the above aspect, it is possible to accurately grasp the heating history of the object to be processed, and after giving the necessary heating history to the object to be processed, cooling is performed. You can go back. As a result, it is not always necessary to investigate the material of the workpiece, such as hardness, obtained by actually carrying out the heat treatment, and experience and labor are not necessarily required to determine the heat treatment conditions.
  • the surface of the workpiece in the surface stabilization step, is more resistant to oxidation than the workpiece in the temperature range where the workpiece is heated. A high stabilization layer is formed. Therefore, in the tempering process, changes in the surface state due to oxidation of the surface of the workpiece are suppressed, and a decrease in temperature measurement accuracy by the radiation thermometer is avoided. As a result, according to the high-frequency heat treatment method in another aspect of the present invention, the quality of the workpiece can be stabilized.
  • temperature control can be performed, heat treatment conditions can be easily set, and the quality of an object to be processed can be stabilized. It is possible to provide a high-frequency heat treatment method that can be performed.
  • a high-frequency heat treatment method that can be performed.
  • the temperature is measured.
  • a high-frequency heat treatment method is a high-frequency heat treatment method in which an object to be treated is heated and tempered by high-frequency heating.
  • the high-frequency heat treatment method includes a data acquisition process, a storage process, a confirmation process, and a mass production process.
  • process data is acquired by heating and tempering the sample of the workpiece.
  • the memory process in order to identify the transition data of the power output output to the induction coil and the cooling power of the sample of the object to be processed in order to heat the sample of the object to be processed in the data acquisition process Are stored as process data.
  • the confirmation step the validity of the power output transition data and the cooling timing data is confirmed based on the material data of the workpiece tempered in the data acquisition step.
  • the workpiece is tempered according to the power output transition data and the cooling timing data that are stored in the storage process and validated in the confirmation process.
  • the tempering in the data acquisition step is performed by the induction heat treatment method according to another aspect of the present invention.
  • induction heat treatment method after performing induction tempering on the sample of the workpiece by the induction heat treatment method according to another aspect of the present invention as a data acquisition step, temperature measurement is performed.
  • a storage process for storing process data such as data is provided, followed by a confirmation process for confirming the validity of the stored process data, and then heat treatment for the mass production process is performed based on the process data for which validity is ensured. Done.
  • temperature control can be performed, heat treatment conditions can be easily set, and the quality of the object to be processed can be further stabilized. Therefore, it is possible to provide a high-frequency heat treatment method capable of performing
  • the material data investigated to confirm the validity of the power output transition data and the cooling timing data is the most important characteristic in tempering the workpiece, for example.
  • the hardness of the workpiece can be set.
  • the material data is stored in the storage process as temperature data measured during the temperature control temperature measurement process and the tempering temperature measurement process in the data acquisition process, and is used as the data and process data.
  • a sample of the workpiece after heat treatment may be actually investigated and acquired.
  • the surface stabilization step includes a black body paint application step in which a black body paint is applied to the surface of the object to be processed.
  • the emissivity change is extremely small over the temperature range where the workpiece is heated!
  • the black body paint for example, a silicon-based mat paint can be used. More specifically, for example, Pyromark High Temperature Paint made by TEMPIL, made by Japan Sensor Co., Ltd. High temperature black body paint JSC No.3 can be used.
  • the surface stabilization step includes a thermal oxidation step in which an iron oxide layer is formed on the surface of the object to be processed by thermal oxidation of the object to be processed.
  • a thermal oxidation step in which an iron oxide layer is formed on the surface of the object to be processed by thermal oxidation of the object to be processed.
  • an oxidation iron oxide layer having higher oxidation resistance than that of the workpiece and a small change in emissivity is formed on the surface of the workpiece, and then high-frequency heat treatment is performed.
  • a change in emissivity on the surface of the object to be processed during the heat treatment is suppressed.
  • the accuracy of temperature measurement with the radiation thermometer is further improved, and the quality of the workpiece is more stable.
  • the iron oxide layer is preferably a thick and acidic iron layer, but the effect is obtained by the acidic iron layer.
  • the degree of formation of the iron oxide layer is preferable to determine the degree of formation of the iron oxide layer in consideration of improving the efficiency of heat treatment.
  • a sample of the object to be processed is heated at a high frequency, and at that time, a contact thermometer such as a thermocouple is brought into contact with the surface of the object to be processed, and the temperature is measured.
  • a radiation thermometer is measured with a radiation thermometer, and the temperature measurement data of both is acquired.
  • the rate of change of the difference between the two temperature measurement data is 3% or less per 10 seconds, it can be considered that a sufficient iron oxide layer has been formed.
  • adjust the emissivity setting of the radiation thermometer By applying, the temperature of the surface of the workpiece on which the iron oxide layer is formed can be accurately measured with a radiation thermometer.
  • the surface stabilization step is an acidic process in which an iron oxide layer is formed on the surface of the object to be processed by immersing the object in an acidic solution. Includes a solution dipping process.
  • an iron oxide layer having higher oxidation resistance than that of the workpiece and having a small change in emissivity is formed on the surface of the workpiece.
  • sulfuric acid, hydrochloric acid, nitric acid, or the like can be used as the acidic solution for immersing the workpiece.
  • the surface temperature of the object to be processed was measured with a contact thermometer and a radiation thermometer in the same manner as described above, and the iron oxide layer was sufficiently formed in the same procedure. It is possible to determine whether or not it is a problem.
  • a high-frequency heat-treated product according to the present invention is characterized by being manufactured by heat treatment using the above-described high-frequency heat treatment method.
  • heat treatment is performed by temperature control, and heat treatment is performed by a high-frequency heat treatment method that makes it easy to determine heat treatment conditions, so that low cost is possible and quality is stable.
  • High-frequency heat-treated products can be provided.
  • the induction heat treatment product of the present invention can be applied to mechanical parts made of steel, such as bearing races and rolling elements, and manufactured by quench hardening.
  • the induction hardening apparatus, induction heat treatment equipment, induction hardening method and high frequency heat treatment method of the present invention can be carried out independently.
  • the induction hardening apparatus of the present invention can be employed.
  • the induction hardening method of the present invention can be employed.
  • the induction hardening method and induction hardening apparatus of the present invention it is possible to control the temperature and easily determine the conditions for the heat treatment. As a result, it is possible to carry out heat treatment easily and efficiently even when there is little accumulation of past production results or when an inexperienced worker performs heat treatment work, and the desired hardness can be applied to a wide range of workpieces. It is possible to provide an induction hardening method capable of imparting heat treatment quality such as the amount of retained austenite and an induction hardening apparatus for performing the induction hardening method. Moreover, according to the induction-hardened product of the present invention, it is possible to provide an induction-hardened product with reduced production costs and stable quality.
  • FIG. 1 is a schematic cross-sectional view showing a configuration of a rolling bearing outer ring that is manufactured by heat treatment using an induction hardening apparatus according to Embodiment 1.
  • FIG. 2 is a schematic diagram showing the configuration of the induction hardening apparatus in the first embodiment.
  • FIG. 3 is a diagram showing an outline of the induction hardening method in the first embodiment.
  • FIG. 4 is a diagram for explaining a method for producing a TTA diagram in the first embodiment.
  • FIG. 5 is a diagram for explaining a method for performing a cooling timing adjustment process using a TTA diagram.
  • FIG. 6 is a schematic cross-sectional view showing the configuration of a rolling bearing outer ring manufactured by heat treatment using the high-frequency heat treatment facility in Embodiment 2.
  • FIG. 7 is a schematic diagram showing a configuration of a high-frequency heat treatment facility in a second embodiment.
  • FIG. 8 is a schematic diagram showing the configuration of an induction hardening apparatus included in the induction heat treatment facility of Embodiment 2.
  • FIG. 9 is a schematic diagram showing the configuration of an induction tempering device included in the induction heat treatment facility of Embodiment 2.
  • FIG. 10 is a diagram showing an outline of an example of a high-frequency heat treatment method using the high-frequency heat treatment equipment of Embodiment 2.
  • FIG. 11 is a diagram for explaining the operation of the induction hardening apparatus in the second embodiment based on the flow of data and commands.
  • FIG. 12 is a diagram for explaining the operation of the induction tempering apparatus according to Embodiment 2 based on the flow of data and instructions.
  • FIG. 15 is a graph showing changes in hardness and processing time with respect to the value of D *.
  • FIG. 16 is a graph showing the temperature transition of the object to be treated during heating.
  • FIG. 20 is a diagram showing a distribution of solute carbon concentrations on the quenching temperature control side and the quenching timing control side when quenching is performed by the quenching cooling timing determination method of the modification. It is a figure which shows the change of the heat transformation point by the temperature increase rate in steel with a carbon content of 1 mass%.
  • FIG. 22 is a diagram for explaining a method of determining the calculation start temperature of the solute carbon concentration in consideration of the rate of temperature rise.
  • FIG. 23 is a condition diagram showing a relationship between a tempering temperature T and a tempering time t for obtaining a predetermined hardness after tempering.
  • FIG. 24 is an explanatory view showing the relationship between the tempering temperature and the holding time for explaining a method of integrating the hardness value after tempering with the temperature transition force.
  • FIG. 25 is a schematic cross-sectional view showing a configuration of a rolling bearing outer ring in the third embodiment.
  • FIG. 26 is a schematic diagram showing the configuration of the induction hardening apparatus in the third embodiment.
  • FIG. 27 is a diagram showing an outline of the induction hardening method in the third embodiment.
  • ⁇ 28 This is a diagram showing an outline of the configuration of the induction hardening apparatus in the fourth embodiment.
  • FIG. 29 is a diagram showing an outline of the induction hardening method in the fourth embodiment.
  • FIG. 30 shows the flow of data and commands in each process of induction hardening according to Embodiment 4.
  • FIG. 30 shows the flow of data and commands in each process of induction hardening according to Embodiment 4.
  • FIG. 31 is a schematic diagram showing the configuration of an induction tempering apparatus used in the induction heat treatment method of Embodiment 5.
  • FIG. 32 shows an outline of the induction tempering method in the fifth embodiment.
  • FIG. 33 is a diagram showing a schematic configuration of an induction tempering apparatus according to Embodiment 6.
  • FIG. 34 shows an outline of the induction tempering method in the sixth embodiment.
  • FIG. 35 is a diagram showing the flow of data and instructions in each step of induction tempering according to the sixth embodiment.
  • FIG. 36 is a diagram showing test results when the outer ring of a rolling bearing made of IS SUJ2 is heated.
  • FIG. 37 is a diagram showing test results when a rolling bearing outer ring made of IS SUS440C is heated.
  • FIG. 38 is a diagram showing test results when a black body paint is applied to the surface of an IS SUS440C rolling bearing outer ring and then heated.
  • rolling bearing outer ring 1 as an induction hardened product in the present embodiment has an annular shape.
  • the rolling bearing outer ring 1 is formed with a rolling surface 1C for rolling while the balls, rollers, etc. as rolling elements are in contact with the inner peripheral surface 1B, and in contact with other members to roll. It has an outer peripheral surface 1A for holding the bearing outer ring against the other members.
  • the rolling bearing outer ring 1 preferably has a hardness of 58H RC or more from the viewpoint of rolling fatigue life and rigidity. From the viewpoint of dimensional stability, the amount of retained austenite is preferably suppressed to 12% by volume or less.
  • the rolling bearing outer ring 1 is manufactured by heat treatment by the induction hardening method in the first embodiment of the present invention using the high-frequency quenching apparatus in the first embodiment of the present invention described below. Therefore, it is an induction-hardened product with reduced manufacturing costs and stable quality.
  • the induction hardening apparatus 90 in this embodiment is an induction hardening method used in an induction hardening method for heating and hardening the entire rolling bearing outer ring 1 as a workpiece by induction heating.
  • a quenching device for adjusting the temperature of the rolling bearing outer ring 1 A temperature control device 50 and a quenching control device 60 for adjusting the timing at which the heated rolling bearing outer ring 1 is to be cooled are provided.
  • the temperature control device 50 acquires temperature data of the rolling bearing outer ring 1, and outputs a temperature information based on the temperature data of the rolling bearing outer ring 1, and the first radiation thermometer 3 as a temperature control temperature measuring device 3
  • a temperature control device 4 connected to the first radiation thermometer 3 and outputting a temperature control signal for controlling the heating state of the rolling bearing outer ring 1 based on the temperature information from the first radiation thermometer 3.
  • a heating device 2 that is connected to the temperature control device 4 and heats the rolling bearing outer ring 1 by high-frequency heating based on a temperature control signal from the temperature control device 4.
  • the quenching control device 60 includes an outer peripheral surface 1A (surface facing the induction coil) which is the high temperature portion of the rolling bearing outer ring 1 and an inner peripheral surface 1B (back side of the surface facing the induction coil) which is the low temperature portion.
  • the first radiation thermometer 3 and the second radiation thermometer 5 are used as temperature measuring devices for quenching, which acquire temperature data of each of them and output temperature information based on the temperature data of the rolling bearing outer ring 1.
  • a cooling timing adjusting device 6 for determining a timing to be output and outputting a cooling start signal; and connected to the cooling timing adjusting device 6; Including a cooling device 7 to cure and harden That.
  • the cooling device 7 is a quenching liquid ejecting device that cools, for example, by injecting a cooling liquid onto the rolling bearing outer ring 1.
  • the first radiation thermometer 3 is installed as both a temperature control temperature measuring device and a quenching control temperature measuring device.
  • the temperature adjustment device 4 and the cooling timing adjustment device 6 are each a personal computer, for example, and one personal computer may serve as both the temperature adjustment device 4 and the cooling timing adjustment device 6.
  • the type of the temperature measuring device used for the temperature controlling temperature measuring device and the quenching temperature measuring device may be a radiation thermometer as described above, but if it is possible in the layout of the device, it is a thermocouple. Any contact thermometer.
  • induction hardening method 10 in the present embodiment is an induction hardening in which the whole object to be treated (rolling bearing outer ring 1) is heated and hardened by induction heating.
  • the temperature control step 20 in which the temperature of the rolling bearing outer ring 1 is adjusted by the temperature control device 50 and the timing at which the heated rolling bearing outer ring 1 should be cooled are determined by the quenching control device 60.
  • the temperature control step 20 includes a temperature control temperature measurement step 23 in which the temperature of the outer ring 1 of the rolling bearing is measured by the first radiation thermometer 3, and a temperature control temperature measurement step 23 by the temperature control device 4. Then, based on the measured temperature information, the temperature adjustment process 24 in which a temperature control signal for controlling the heating state of the rolling bearing outer ring 1 is output, and the heating device 2 is used, based on the temperature control signal, And a heating step 22 in which the rolling bearing outer ring 1 is heated by high frequency heating.
  • the quench control process 30 includes a quenching temperature measurement process 35, a cooling timing adjustment process 36, and a cooling process 37.
  • the temperature measurement process 35 for quenching in the outer ring 1 of the rolling bearing, the temperature rise due to high-frequency heating is the largest in the outer ring 1 of the rolling bearing, and the outer peripheral surface 1A as a high-temperature part, which is the surface portion, and the high-frequency heating.
  • the temperature rise due to the temperature is measured by the first radiation thermometer 3 and the second radiation thermometer 5, respectively, with the inner peripheral surface 1B as the low temperature part, which is the smallest surface portion of the rolling bearing outer ring 1. .
  • the cooling timing adjustment device 6 adjusts the heating time based on the temperature information measured in the quenching temperature measurement step 35, and determines when the rolling bearing outer ring 1 should be cooled. Then, a cooling start signal is output. In the cooling process 37, the cooling device 7 cools the rolling bearing outer ring 1 to a temperature range that is not less than the point A and not higher than the point M based on the cooling start signal. Hardened
  • the temperature history force including the temperature on the outer peripheral surface 1A and the calorie heat time.
  • the temperature history at which the amount of retained austenite less than the upper limit of the desired amount of retained austenite obtained in advance is obtained.
  • Temperature history including the temperature and heating time on the inner peripheral surface 1B, satisfying the condition of (temperature results at each time after heating starts) Force The heating time is adjusted so as to satisfy the condition of temperature history for obtaining a hardness equal to or higher than the lower limit of the desired hardness obtained in advance, and a cooling start signal is output.
  • the adjustment of the heating time includes the conditional expression showing the relationship between the heating time and the heating temperature for obtaining the desired hardness obtained in advance, and the heating time and calorie for obtaining the desired amount of retained austenite. This is implemented based on a conditional expression showing a relationship with the heat temperature.
  • the temperature can be controlled and the conditions for the heat treatment can be easily determined. Quenching and hardening can be performed easily and efficiently, even when there is little accumulation of past production results, or when inexperienced workers perform heat treatment work, and rolling bearing outer rings as workpieces Heat treatment quality such as desired hardness and retained austenite amount can be imparted to a wide range of 1.
  • point A is a point corresponding to a temperature at which the steel structure starts transformation from ferrite to austenite when the steel is heated.
  • the S point refers to the point corresponding to the temperature at which martensite cracking starts when austenitic steel is cooled.
  • cooling timing adjustment step 36 for example, a TTA (Time Temperature Austinitization) diagram is created as shown below and based on the conditional expression in the TTA diagram! This can be done by adjusting the heating time.
  • TTA Time Temperature Austinitization
  • a small test piece made of SUJ2 capable of uniform heating and cooling (6206 model ball bearing outer ring, outer ring ⁇ 62mm, inner diameter ⁇ 52mm, thickness tl6mm ring shape) Quenching is performed by heating at various heating rates and quenching after various times, and further tempering the specimen by holding at 180 ° C for 120 minutes. Then, the amount of retained austenite and the hardness of each test piece are measured.
  • the hardness of the test piece can be obtained, for example, by polishing a part of the workpiece after the heat treatment and measuring the hardness of the polished surface with a hardness meter such as a Rockwell hardness meter or a Vickers hardness meter.
  • the amount of retained austenite can be determined by, for example, electropolishing a test piece after heat treatment, and using an X-ray diffractometer (XRD) to diffract the polished surface from the manoletensite ⁇ (211) surface and the austenite ⁇ (220) surface. It can be calculated by measuring the intensity.
  • XRD X-ray diffractometer
  • Fig. 4 shows the heating history of the specimen when the heating rate is about 311 ° CZ seconds (dashed line), about 65 ° CZ seconds (dashed line), and about 20 ° CZ seconds (solid line). Yes.
  • the heating rate is 311 ° C for Z seconds
  • the point at which the hardness is 58HRC is indicated by a
  • the point at which the amount of retained austenite is 12% by volume is indicated by ⁇ .
  • the hardness at about 65 ° CZ seconds is 58HRC.
  • FIG. 5 shows the horizontal axis representing the elapsed time from the start of heating, and the vertical axis represents the temperature.
  • FIG. 5 also shows the temperature measurement results of the high temperature part (outer peripheral surface 1A) and the low temperature part (inner peripheral surface 1B) of the rolling bearing outer ring 1 during high frequency heating.
  • the hardness: 58HRC curve shows that the hardness is 58HRC or higher on the higher temperature side than the curve, and the calculated curve formula is
  • the curve of residual austenite 12% by volume shows that the amount of residual austenite is 12% by volume or less on the lower temperature side than the curve, and the calculated curve formula is
  • a cooling start signal is output during a time period greater than ⁇ , and the workpiece (rolling
  • the outer ring 1) is cooled and hardened by cooling.
  • peripheral surface 1B is higher than the curve of hardness: 58HRC, and the temperature of the hot part (outer peripheral surface 1A) is lower than the curve of residual austenite content: 12% by volume.
  • the entire workpiece can be hardened with a hardness of 58H RC and a residual austenite amount of 12% by volume or less.
  • rolling bearing outer ring 201 as the high frequency heat treatment product in the present embodiment has an annular shape.
  • the rolling bearing outer ring 201 is formed with a rolling surface 201C for rolling while the balls, rollers, and the like as rolling elements are in contact with the inner peripheral surface 201B, and in contact with other members, the rolling bearing It has an outer peripheral surface 201 A that holds the outer ring against the other members.
  • the rolling bearing outer ring 201 preferably has a hardness of 58 HRC or more from the viewpoint of rolling fatigue strength and rigidity. From the viewpoint of dimensional stability, the amount of retained austenite is preferably suppressed to 12% by volume or less.
  • the rolling bearing outer ring 201 is manufactured by heat treatment using the high-frequency heat treatment equipment in Embodiment 2 of the present invention described below, the production cost is suppressed, and high-frequency heat treatment with stable quality is achieved. It is a product.
  • the induction heat treatment equipment of the present embodiment is an induction heat treatment equipment for heating an object to be treated (for example, rolling bearing outer ring 201) by high frequency heating,
  • a workpiece holding device 291, a workpiece confirmation device 292, an induction hardening device 293, a cleaning device 294, an induction tempering device 295, and a heat treatment product holding device 296 are provided.
  • the apparatus is connected in this order from the conveyors 299A, 299B, 299C, 299D, and 299E.
  • the workpiece holding device 291 includes, for example, a basket that holds a rolling bearing outer ring 201 that is a workpiece, and has a function of holding the rolling bearing outer ring 201 before heat treatment.
  • the workpiece confirmation device 292 includes, for example, a shape discriminating device for measuring the shape of the rolling bearing outer ring 201, and the outer diameter size of the rolling bearing outer ring 201 conveyed from the workpiece holding device 291 by the conveying device 299A. It has a function to confirm that there is no contamination by measuring the width, etc.
  • the induction hardening device 293 includes, for example, an induction coil, a high frequency power source, a quenching oil tank, etc., and has a function of heating and hardening the rolling bearing outer ring 201 conveyed by the conveying device 299B by high frequency heating. is doing.
  • Cleaning device 294 includes a cleaning tank for storing cleaning liquid, a drying device for drying rolling bearing outer ring 201 after cleaning, and the like. By cleaning, it has a function of removing deposits such as quenching oil adhering to the surface of the rolling bearing outer ring 201 in the quench hardening process.
  • the induction tempering apparatus 295 is connected to the induction hardening apparatus 293 via the cleaning apparatus 294 and the conveying apparatuses 299C and 299D, and is hardened and hardened in the induction hardening apparatus 293, and is a rolling bearing conveyed by the conveying apparatuses 299C and 299D.
  • the outer ring 201 has a function of heating and tempering by high frequency heating.
  • the heat-treated product holding device 296 includes, for example, a basket that holds the rolling bearing outer ring 201, and has a function of holding the heat-treated product after quenching and tempering.
  • a high-frequency quenching device 293 cools the quenching temperature control device 250 for adjusting the temperature of the rolling bearing outer ring 201 that is the object to be processed, and the heated rolling bearing outer ring 201.
  • the quenching timing control device 260 for adjusting the power timing and the quenching temperature control device 250 the quenching power source is supplied from the quenching power source to the quenching induction coil to heat the rolling bearing outer ring 201.
  • the quenching output transition data which is the transition data of the power output that is applied, and the quenching cooling timing data for specifying the timing when the rolling bearing outer ring 201 is cooled in the quenching timing control device 260 are quenched.
  • a quenching storage device 270 which stores it as process data.
  • the quenching temperature control device 250 acquires the temperature data of the rolling bearing outer ring 201, outputs the temperature information based on the temperature data of the rolling bearing outer ring 201, and the quenching temperature control temperature measuring device 203.
  • Quenching temperature control device 203 is connected to the quenching temperature control temperature measuring device 203 and outputs a quenching temperature control signal for controlling the heating state of the rolling bearing outer ring 201 based on the power temperature information.
  • a quenching power source connected to the temperature control device 204 and the quenching temperature control device 204, which heats the rolling bearing outer ring 201 by high-frequency heating based on the quenching temperature control signal from the quenching temperature control device 204, and And a quenching heating device 202 including a quenching induction coil.
  • the quenching timing control device 260 acquires temperature data of the rolling bearing outer ring 201 and outputs temperature information based on the temperature data of the rolling bearing outer ring 201. It is connected to the quenching timing control temperature measuring device 205, adjusts the heating time based on the temperature information from the quenching timing control temperature measuring device 205, and determines the timing at which the rolling bearing outer ring 201 should be cooled.
  • the quenching timing adjusting device 206 that outputs a quenching cooling start signal and the quenching timing adjusting device 206 are connected to the rolling bearing outer ring 201 by cooling the rolling bearing outer ring 201 based on the cooling start signal. And a quenching cooling device 207 for quench hardening.
  • the quenching cooling device 207 holds an oil tank 207B in which quenching oil is stored and a rolling bearing outer ring 201 which is an object to be processed, and moves or tilts based on a cooling start signal to roll.
  • a workpiece holding base 207A for feeding the bearing outer ring 201 into the oil tank 207B is provided.
  • the quenching storage device 270 is connected to the quenching and heating device 202, the quenching temperature adjusting device 204, and the quenching timing adjusting device 206.
  • the induction tempering device 295 includes a tempering temperature control device 251 for adjusting the temperature of the rolling bearing outer ring 201 that is the object to be processed, and a heated rolling bearing outer ring.
  • Tempering end timing control device 261 for adjusting the timing at which 01 should be cooled
  • the tempering output transition that is the transition data of the power output output to the induction coil for tempering Tempering end timing control device 261 includes a tempering storage device 271 for storing tempering cooling timing data for specifying the timing at which the rolling bearing outer ring 201 is cooled as tempering process data. It is out.
  • the tempering temperature control device 251 acquires temperature data of the rolling bearing outer ring 201, outputs temperature information based on the temperature data of the rolling bearing outer ring 201, and a tempering temperature control temperature measuring device 213.
  • Tempering temperature control device 213 is connected to the tempering temperature control temperature sensor 213 and outputs a tempering temperature control signal for controlling the heating state of the rolling bearing outer ring 201 based on the temperature information of the tempering temperature control 213.
  • a temperature control device 214 and a tempering power supply and a tempering device connected to the tempering temperature control device 214 and heating the bearing outer ring 201 by high frequency heating based on a tempering temperature control signal from the tempering temperature control device 214.
  • a tempering heating device 212 including a return induction coil.
  • a tempering end timing control device 261 obtains temperature data of the rolling bearing outer ring 201 and outputs temperature information based on the temperature data of the rolling bearing outer ring 201.
  • the tempering end timing control temperature measuring device 215 is connected, the heating time is adjusted based on the temperature information from the tempering end timing control temperature measuring device 215, and the timing at which the rolling bearing outer ring 201 should be cooled is determined.
  • the tempering end timing adjusting device 216 that outputs a tempering cooling start signal and the tempering end timing adjusting device 216 are connected to cool the rolling bearing outer ring 201 based on the tempering cooling start signal 216.
  • a tempering end device 217 for ending the tempering of the rolling bearing outer ring 201.
  • the tempering end device 217 has a function of, for example, holding the rolling bearing outer ring 201 and moving the rolling bearing outer ring 201 from the heating range by the induction coil for tempering by moving based on the tempering cooling start signal. It has a to-be-processed object holding stand.
  • the tempering storage device 271 is connected to a tempering heating device 212, a tempering temperature adjusting device 214, and a tempering end timing adjusting device 216.
  • the induction heat treatment method of the present embodiment includes a quenching condition determining step, a tempering condition determining step, a final confirmation step, and a mass production step.
  • the quenching condition determination step for determining the quenching condition and the tempering condition determination process for determining the tempering condition are performed independently to determine the quenching condition and the tempering condition, respectively.
  • a final confirmation process is performed to confirm the appropriateness of the quenching conditions and tempering conditions when quenching and tempering are continuously performed.
  • the mass production process is then carried out based on the quenching and tempering conditions that have been validated.
  • the quenching condition determination step will be described.
  • a quenching data acquisition step in which process data is acquired by heating and quenching the sample of the rolling bearing outer ring 201 as the object to be processed.
  • Temporary heat treatment conditions for carrying out this quenching data acquisition process can be determined as conditions in which the operator also has conditions of temperature and time. Therefore, even when the past production record is sufficient or when the worker has sufficient experience in heat treatment, it can be easily determined.
  • a quenching data storage step is performed in which the transition data and quenching cooling timing data for specifying the cooling timing of the sample of the rolling bearing outer ring 201 are stored as quenching process data.
  • the quenching condition confirmation that the validity of the quenching output transition data and quenching cooling timing data is confirmed. The process is carried out.
  • the validity of the quenching output transition data and the quenching cooling timing data is, for example, the material data of the sample of the rolling bearing outer ring 201 actually hardened and hardened.
  • the microstructure of the steel constituting the outer ring 201, the amount of retained austenite, etc. are actually measured by experiments, and it is judged whether these materials are within the range of the desired standard.
  • the material data stores the temperature transition data of the workpiece in the quenching data acquisition process, and based on the data and quenching cooling timing data, It is also possible to estimate.
  • the quenching condition confirmation process if the material data of the rolling bearing outer ring 201 that is the object to be processed is not within the desired standard range, for example, a condition that is lower than the initial provisional heat treatment condition and for a long time.
  • the tempering data acquisition process is performed again by changing the provisional heat treatment condition so that the heating is performed at the same time.
  • the material data of the rolling bearing outer ring 201, which is the workpiece is within the desired standard range in the quenching condition confirmation process, the transition of the quenching output stored in the quenching data storage process is stored.
  • the data and quenching cooling timing data are determined as heat treatment conditions (quenching conditions) for performing quench hardening by power control.
  • the tempering condition determination step first, the process data is acquired by heating and tempering the sample of the rolling bearing outer ring 201 as the hardened and hardened workpiece. Tempering data acquisition process is implemented. Temporary heat treatment conditions for carrying out this tempering data acquisition process can also be given in terms of temperature and time, so that past production results are sufficient as in the case of the quenching data acquisition process! Even if the worker has sufficient experience in heat treatment, it can be easily determined.
  • the power supply power for high-frequency heating to heat the sample of the rolling bearing outer ring 201, the output transition data for tempering output to the induction coil, and the cooling of the sample of the rolling bearing outer ring 201 A tempering data storage step is performed in which tempering cooling timing data for specifying timing is stored as tempering process data. Then, based on the material data of the rolling bearing outer ring 201 tempered in the tempering data acquisition step, there is a tempering condition confirmation step in which the validity of the tempering output transition data and the tempering cooling timing data is confirmed. To be implemented.
  • the validity of the tempering output transition data and the tempering cooling timing data is, for example, the hardness that is most important in the material data of the sample of the outer ring 201 of the rolling bearing outer ring that has been actually tempered. Is actually measured by experiment, and is judged by whether the hardness is within the range of the desired standard.
  • the material data stores the temperature transition data of the workpiece in the tempering data acquisition process, and the tempering cooling timing data. It is also possible to estimate based on
  • the tempering condition confirmation process if the material data of the rolling bearing outer ring 201, which is the object to be processed, is not within the desired standard range, for example, a condition at a lower temperature and longer time than the initial provisional heat treatment condition.
  • the tempering data acquisition step is performed again by changing the provisional heat treatment conditions so that the heating is performed at the same time.
  • the tempering output stored in the tempering data storage step! Transition data and cooling timing data for tempering are determined as heat treatment conditions (tempering conditions) for performing tempering by electric power control.
  • the final confirmation process power control is first performed based on the quenching condition determined in the quenching condition determination process and the tempering condition determined in the tempering condition determination process.
  • a mass production test process in which quenching and tempering are continuously performed on the rolling bearing outer ring 201 as the object to be processed is performed.
  • the validity of the quenching condition determined in the quenching condition determination process and the tempering condition determined in the tempering condition determination process is performed.
  • a heat treatment condition confirmation process for confirming is performed.
  • the appropriateness of the quenching condition determined in the quenching condition determination step and the tempering condition determined in the tempering condition determination step is, for example, the rolling that is actually quenched and tempered.
  • the hardness which is the material data of the sample of the bearing outer ring 201, the microstructure of the steel constituting the rolling bearing outer ring 201, the amount of retained austenite, etc. are actually measured by experiments, and these materials are within the range of the desired standard. It is judged by whether or not.
  • the heat treatment condition confirmation step if the material data of the rolling bearing outer ring 201 that is the object to be processed is not within the desired specification range, it is determined whether the cause is the quenching condition or the tempering condition.
  • the cause identifying step is performed. This cause identification process can be performed based on, for example, the material data acquired through the heat treatment condition confirmation process. That is, only the hardness of the material data, the microstructure of the steel constituting the rolling bearing outer ring 201, and the amount of retained austenite is outside the standard range of the material.
  • the tempering conditions are considered to be the cause of the quenching conditions that affect the microstructure and retained austenite content.
  • the tempering condition determination step is performed again in consideration of the material data.
  • the quenching condition determination process is performed again in consideration of the material data. Then, the final confirmation process is performed again based on the determined quenching conditions and tempering conditions.
  • the heat treatment condition confirmation step when the material data of the rolling bearing outer ring 201 which is the object to be processed is within a desired standard range, the heat treatment condition for performing quenching and tempering by electric power control is The quenching conditions and tempering conditions are determined. Based on these quenching conditions and tempering conditions, a mass production process for quenching and tempering by electric power control is performed.
  • FIG. 11 the flow of data and commands in the quenching data acquisition process is solid arrows, the flow of data and commands in the quenching data storage process is broken arrows, and the flow of data and commands in the final confirmation process and mass production process is Displayed with double solid arrows.
  • the operation of the induction hardening apparatus in the present embodiment will be described with reference to FIG. 8, FIG. 10, and FIG.
  • the quenching data acquisition process first, temporary quenching conditions by temperature control are determined, and the heat treatment conditions are determined by quenching temperature control apparatus 204 and It is input to the quenching timing adjusting device 206 and heat treatment is started.
  • the temperature data of the sample of the rolling bearing outer ring 201 as the workpiece measured by the temperature measuring device 203 for quenching temperature control is sent to the quenching temperature adjusting device 204.
  • the target heating temperature of the rolling bearing outer ring 201 and the obtained temperature data power of the sample of the rolling bearing outer ring 201 are also determined, and the necessary power output is also determined. Command output.
  • the quenching power source Upon receiving the command, the quenching power source outputs power to the quenching induction coil of the quenching heating device 202, and the sample of the rolling bearing outer ring 201 is heated to a target temperature.
  • the sample temperature data of the rolling bearing outer ring 201 measured by the quenching timing control temperature measuring device 205 is sent to the quenching timing adjusting device 206.
  • the cooling timing is judged from the obtained temperature and heating time of the sample of the rolling bearing outer ring 201, and the cooling start device 207 is instructed to start cooling. Thereby, the sample of the rolling bearing outer ring 201 is rapidly cooled and quenched and hardened.
  • the temperature data acquired by the quenching temperature control unit 204 and the quenching timing control unit 206 is quenched as temperature transition data. It is stored in the incoming storage device 270.
  • the power output output from the quenching power source of the quenching heating device 202 to the quenching induction coil is stored in the quenching storage device 270 as quenching output transition data.
  • the timing of the cooling start command output from the quenching timing adjusting device 206 to the quenching cooling device 207 is stored in the quenching storage device 270 as quenching cooling timing data.
  • the quenching cooling timing is stored as the time from the start of heating, for example.
  • the quenching condition confirmation process after the validity of the quenching output transition data and quenching cooling timing data is confirmed based on the material data of the sample of the rolling bearing outer ring 201, the final confirmation In the process and the mass production process, the rolling bearing outer ring 201 is heated and quenched based on the quenching output transition data and quenching cooling timing data stored in the quenching storage device 270.
  • the induction hardening apparatus 293 directly responds to material changes due to quenching, and therefore quenching by temperature control that allows easy setting of quenching conditions, and the flow of data and commands. It is simple and can be implemented by switching between quenching with highly reliable power control. As a result, even if the past production results are not sufficient or when a worker with little experience in heat treatment is working, the desired hardness to be imparted to the workpiece and the residual steel constituting the workpiece. From the austenite amount and microstructure, the quenching data acquisition process can be performed under quenching conditions with temperature control that can be easily set. In the mass production process, quenching can be performed by highly reliable power control based on quenching conditions that have been validated.
  • FIG. 12 the flow of data and commands in the tempering data acquisition process is solid arrows, the flow of data and commands in the tempering data storage process is broken arrows, and the flow of data and commands in the final confirmation process and mass production process is Displayed with double solid arrows.
  • the operation of the induction tempering apparatus according to the present embodiment will be described with reference to FIG. 9, FIG. 10, and FIG.
  • a temporary tempering condition is determined by temperature control, and the heat treatment condition is determined by tempering temperature adjusting device 214 and It is input to the tempering end timing adjustment device 216 and heat treatment is started.
  • the temperature data of the sample of the rolling bearing outer ring 201 as the object to be processed measured by the tempering temperature control temperature measuring device 213 is sent to the tempering temperature adjusting device 214.
  • the target heating temperature of the rolling bearing outer ring 201 and the obtained temperature data of the sample of the rolling bearing outer ring 201 are also determined to determine the necessary power output, and the tempering power supply for the tempering heating device 212 is used. Command the power output to.
  • the power supply for tempering that receives the command outputs electric power to the induction coil for quenching of the tempering heating device 212, and the sample of the rolling bearing outer ring 201 is heated to a target temperature.
  • the temperature data of the sample of the rolling bearing outer ring 201 measured by the tempering end timing control temperature measuring device 215 is sent to the tempering end timing adjusting device 216.
  • the tempering end timing adjusting device 216 the cooling timing is judged from the obtained temperature and heating time of the sample of the rolling bearing outer ring 201, and the tempering end device 217 is instructed to start the cooling. Thereby, the sample of the rolling bearing outer ring 201 is cooled, and the tempering is finished.
  • the temperature data acquired by the tempering temperature adjustment device 214 and the tempering end timing adjustment device 216 is used as temperature transition data in the tempering data acquisition step. It is stored in the tempering storage device 271.
  • the power output output from the tempering power supply of the tempering heating device 212 to the tempering induction coil is stored in the tempering storage device 271 as tempering output transition data.
  • the timing of the cooling start command output from the tempering end timing adjusting device 216 to the tempering end device 217 is stored in the tempering storage device 271 as tempering cooling timing data.
  • the tempering cooling timing timing data is For example, it is stored as the time from the start of heating.
  • the tempering condition confirmation step the validity of the tempering output transition data and the tempering cooling timing data is confirmed based on the sample material data of the rolling bearing outer ring 201, and then the final confirmation.
  • the rolling bearing outer ring 201 is heated and tempered based on the tempering output transition data and the tempering cooling timing data stored in the tempering storage device 271.
  • the flow of data and commands is simple with tempering by temperature control in which tempering conditions can be easily set. Yes, it is possible to switch between tempering with highly reliable power control. As a result, even if the past production record is not sufficient or when an operator with little experience in heat treatment is working, the quenching data acquisition process is performed under quenching conditions with temperature control that can be set easily. In the mass production process, tempering can be performed with reliable power control based on the tempering conditions that have been validated.
  • conveying apparatuses 299C, 299D, and 299E are configured to be able to take out an object to be processed.
  • the transport apparatuses 299C, 299D, and 299E are provided with a cover
  • the cover is provided with a workpiece extraction port that can be opened and closed.
  • a branch that can change the transport direction of the object to be processed may be provided to take out the object to be processed.
  • the quenching storage device 270 may be installed as an independent device.
  • the quenching temperature control device 204 and the quenching timing adjustment may be performed by a personal computer having a storage unit such as a node or a disk.
  • a device such as the device 206 may also be installed.
  • the tempering storage device 271 may be installed as an independent device, but for example, a tempering temperature adjustment device 214, tempering end timing adjustment can be performed by a personal computer having a storage unit such as a node disk.
  • a device such as the device 216 may also be installed.
  • each step of the above-described high-frequency heat treatment method is performed, for example, as a personal device as a control device. This can be implemented by operating the personal computer using one or more programs corresponding to each process.
  • the hardness after tempering when tempering at 180 ° C is strength strength HRC58 or higher (HV653 or higher), and the amount of retained austenite is 1 from the viewpoint of dimensional stability.
  • the standard value is set to 2% by volume or less.
  • FIG. 13 is a TTA (Time Temperature Austinitization) diagram of the SUJ2 material showing the relationship between the quenching temperature and the holding time for satisfying the standard value of heat treatment.
  • the horizontal axis represents the quenching temperature (° C)
  • the vertical axis represents the holding time (seconds).
  • Region A is a range that does not satisfy the hardness standard
  • region B is a range where the retained austenite amount does not satisfy the standard
  • region C is a range that satisfies any heat treatment quality standard.
  • provisional heat treatment conditions conditions for heating temperature and heating time in quenching
  • the hardness of the rolling bearing outer ring 201 made of SUJ2 easily satisfies the standard as the quenching temperature and the holding time increase.
  • the amount of austenite satisfies the standard as the quenching temperature and holding time increase.
  • setting the conditions for a long time at a relatively low temperature makes it easier to control the heat treatment quality.
  • the holding time for ensuring the heat treatment quality standard is 15 seconds or longer, but if the holding time is 17 seconds or longer, the standard cannot be satisfied.
  • the holding time for ensuring the heat treatment quality is 20 seconds or more, and the standard can be satisfied up to 60 seconds.
  • FIG. 13 shows a TTA diagram related to SUJ2.
  • a temporary heat treatment condition can be determined in the same manner as described above by creating a TTA diagram corresponding to the force material.
  • the heat treatment conditions are input to a quenching temperature adjusting device 204 such as a personal computer with reference to FIG.
  • the quenching temperature control device 204 is connected to the quenching temperature control temperature measuring device 203 and the quenching heating device 202.
  • the PID Proportional With the integral differential control, a quenching temperature control signal is output to the quenching and heating device 202, and the temperature transition of the outer peripheral surface 201A that is the temperature measuring unit of the quenching temperature control temperature measuring device 203 can be controlled.
  • the outer peripheral surface 201A has the largest penetration of magnetic flux in the rolling bearing outer ring 201, and is the largest temperature rise due to high frequency heating.
  • the temperature measurement data of the quenching timing control temperature measuring device 205 is taken into the quenching timing adjusting device 206 such as a personal computer, and it is determined from the temperature transition whether the heating is sufficient, Adjust the cooling timing.
  • the determination of the cooling timing is made based on whether or not the temperature transition of the inner peripheral surface 201B, which is the temperature measuring portion of the quenching timing control temperature measuring device 205, falls within the standard on the TTA diagram.
  • the inner peripheral surface 201B is a portion where the penetration of the magnetic flux is the smallest in the rolling bearing outer ring 201 and the temperature rise due to the high frequency heating is the smallest.
  • the quenching temperature adjusting device 204 and the quenching timing adjusting device 206 can be used as the same personal computer.
  • Equation (3) and formula (5) A force that can use the following formula (3) and formula (5) for determining whether or not the TTA diagram is within the specification, that is, determining the quenching cooling timing, is preferably treated. Equations (4) and (5), which are obtained by correcting Equation (3) in consideration of the fact that the temperature of a physical object changes every moment, are used.
  • D diffusion constant of carbon in steel
  • t retention time (seconds)
  • A correction factor
  • D D exp (—QZRT) ⁇ ⁇ ⁇ ⁇ (5)
  • D Entropy term of diffusion constant
  • Q Activity energy
  • R Gas constant
  • T Absolute temperature
  • the value of the correction coefficient A is a value obtained by the following equation (6).
  • Equation (4) is an equation that calculates the diffusion length D of carbon when the value of C in Equation (6) becomes C.
  • thermodynamic equilibrium calculation it can be determined by thermodynamic equilibrium calculation. Cooling is performed when the value of carbon diffusion length D in equation (4) reaches a certain value (D *).
  • the temperature measuring unit 205 of the quenching timing control temperature measuring device 205 does not necessarily have to be one place. By using a plurality of temperature measuring sections, it is possible to ensure heat treatment quality at a plurality of sites.
  • the horizontal axis is time t and the vertical axis is temperature T.
  • the quenching temperature control side (outer peripheral surface 201A of the rolling bearing outer ring 201) and the quenching timing control side (rolling bearing outer ring).
  • the temperature transition on the inner peripheral surface 201B) of 201 is shown.
  • the upper right figure is an enlarged view of the area ⁇ in the upper left graph.
  • the lower part shows the formula for integrating the ep value of correction D from the temperature transition!
  • the temperature measurement part for determining the cooling timing that is, the inner peripheral surface which is the temperature measurement part of quenching timing control temperature measurement device 205) Since the temperature of 201B) changes from moment to moment, the value of correction D (corrected D in equation (4), hereinafter referred to as D in ep ep) is calculated as D ⁇ D ⁇ D as shown in Fig. 14. Need to ep el ep2 epn
  • the quenching timing control side (inner peripheral surface 201B side) has less magnetic flux entering than the quenching temperature control side (outer peripheral surface 201A side).
  • the temperature rises with a delay compared to the side. Normally, when the temperature exceeds 727 ° C, iron austenite starts, but when the heating rate is fast, the iron transformation temperature changes. Therefore, the temperature for calculating the diffusion length must be changed according to the heating rate.
  • the rate of temperature rise varies depending on the power source capacity, the shape of the coil and workpiece, etc. It is preferable that the temperature for calculating the diffusion length is appropriately changed depending on the type of the apparatus and the object to be processed. From the point where the quenching timing control temperature exceeds the heating transformation temperature, the diffusion length D is calculated using the formula in the figure. If D force 3 ⁇ 4 * at any time is exceeded, ep epn ep
  • the value of D * is within the range that can maintain the prescribed heat treatment quality.
  • the value is as small as possible from the viewpoint of reducing the heat treatment time. However, it is desirable to set the viewpoint that stabilizes the quality to a set value that is somewhat safe.
  • Figure 15 shows the results when the maximum temperature reached 900 ° C, the temperature drop rate was 0 ° CZ seconds, and tempering was performed at 180 ° C for 120 minutes after quenching.
  • the horizontal axis indicates the value of D * (m ep m), and the vertical axis indicates the hardness (HV) and the processing time (seconds).
  • black circles indicate hardness and white circles indicate processing time.
  • the value of * is considered to be desirable to be 0.015mm or less.
  • D * is set to 0.015 mm, and D accumulated as described above becomes 0.015 mm ep epn
  • a cooling start signal is output from the quenching timing adjusting device 206 to the quenching cooling device 207, whereby the cooling timing is determined. Based on this, the quenching cooling device 207 moves the rolling bearing outer ring 201 from the temperature of the A point or higher to the temperature of the M point or lower.
  • the rolling bearing outer ring 201 is hardened and hardened.
  • the quenching cooling timing in the present modification is determined using Equation (7) and Equation (5).
  • Cooling timing is determined by solving Equation (8) under certain boundary conditions and determining whether the solid solution state of carbon in the material satisfies a predetermined condition.
  • the boundary condition is, for example, iron carbide (cementite; Fe C) and the base material in the steel constituting the rolling bearing outer ring 201 during heating.
  • the carbon solid solution concentration at a certain temperature can be given under the assumption that the solid solubility of carbon at that temperature is equal.
  • the horizontal axis represents time (seconds), and the vertical axis represents temperature (° C).
  • the horizontal axis represents the distance (position) (mm) from the reference boundary point, and the vertical axis represents the carbon concentration (mass%).
  • the distance between 3 is 0.012 mm, and the amount of solute carbon (carbon concentration at the boundary point (the interface between Fe C and substrate))
  • the value (mass%) was set to a value (calculated with thermodynamic equilibrium calculation software) that can also obtain the solid solubility curve force of SUJ2.
  • This solid solubility curve equation (solid solubility equation) can be obtained in advance for each material by experimental or thermodynamic equilibrium calculation.
  • the solute carbon concentration is lowest at the position of 0.006 mm), and as the time passes, the solute carbon concentration increases as a whole and the central position And the difference between both ends (the interface between Fe C and the substrate) tends to be small.
  • the quenching cooling timing can be determined, for example, as the point in time when the inner peripheral surface 201B of the rolling bearing outer ring 201 satisfies the above-described quenching condition of the solute carbon concentration at the center position.
  • the distance between two boundary points can be appropriately changed depending on the difference in structure and material before quenching of the workpiece.
  • the quenching cooling timing in this modification is determined as follows, for example.
  • the quenching timing control side temperature is measured by the quenching timing control temperature measuring device 205 (step A), and the carbon content at the boundary is calculated from the measured temperature (step B).
  • Equation (8) is calculated by applying the boundary carbon content to the boundary condition of Equation (8) (Step C).
  • Step D it is possible to calculate the solid solution carbon concentration distribution as shown in Fig. 17 to Fig. 19 (Step D). From the obtained solute carbon concentration distribution, it is confirmed whether the carbon concentration at the center of the solute carbon concentration distribution is a predetermined carbon concentration (eg, 0.6 to 0.8 mass%). (Step E). If the carbon concentration at the central position has reached the predetermined carbon concentration, cooling is started (Step F). If not, cooling is not started and heating is continued and the process returns to Step A again.
  • a predetermined carbon concentration eg, 0.6 to 0.8 mass%
  • the carbon concentration at both ends of the carbon distribution in Figs. 17 to 19 is the carbon concentration at the carbide substrate interface. Therefore, carbon is supplied from this position to the substrate at a certain concentration (solid solubility of carbon).
  • C binding is located at the interface between carbide and substrate.
  • the formula power of solid solubility can also give the value of carbon concentration. As a result, there are five simultaneous equations and five unknowns, so the values of C, C, C, C, and C can be obtained.
  • Fig. 20 shows the quenching temperature control side (temperature control side) and the quenching timing control side (quenching control side) when quenching is performed by the quenching cooling timing determination method of this variation. It is a figure which shows distribution of the solid solution carbon concentration in.
  • the horizontal axis represents the distance (position) (mm) of the reference boundary point force, and the vertical axis represents the carbon concentration (mass%).
  • This data shows that the quenching temperature (heating temperature) is constant at 950 ° C, the heating rate up to the quenching temperature is 300 ° CZ seconds, the distance between carbides is 0.012 mm, and the cooling start condition is the carbon concentration. When the value at the center position is 0.6 mass%. From FIG.
  • solute carbon concentration value is generally higher on the quenching temperature control side than on the quenching timing control side. This is because the induction coil for quenching included in the quenching heating device 202 in the outer ring 201 of the rolling bearing. This is because the temperature on the quenching temperature control side is higher than that on the quenching timing control side.
  • the starting temperature of the calculation of the above-mentioned solid solution carbon concentration that is, the starting temperature of the solid solution of carbon in the substrate, in consideration of the rate of temperature rise.
  • the determination method will be described below.
  • the horizontal axis indicates the heating rate (° CZ seconds), and the vertical axis indicates the heating transformation point A (° C).
  • the heating transformation point A changes from 727 ° C to 950 ° C.
  • the heating transformation point A is obtained from the velocity, and the above solute carbon is calculated based on the heating transformation point A.
  • the concentration calculation start temperature (carbon solid solution start temperature) can be determined.
  • the horizontal axis represents time, and the vertical axis represents temperature. 22 shows the temperature transition on the quenching temperature control side (outer peripheral surface 201A of the rolling bearing outer ring 201 in FIG. 8) and the temperature on the quenching timing control side (inner peripheral surface 201B of the rolling bearing outer ring 201 in FIG. 8). Transition and heating transformation point A
  • the heating on the quenching temperature control side is rapidly performed, so the heating rate on the quenching timing control side is also increased, and the heating transformation point is increased.
  • the temperature on the quenching temperature control side approaches a predetermined set temperature
  • heating is controlled by the quenching temperature adjusting device 204 so that the rate of temperature rise becomes slow.
  • the rate of temperature increase on the quenching timing control side also becomes moderate, and the heating transformation point A decreases.
  • the heating transformation point A intersects with the temperature transition on the quenching timing control side. This intersection is
  • the calculation of the solute carbon concentration can be started from the temperature of this intersection (that is, the start temperature of the austenite cake).
  • X rate of change of mechanical properties
  • k reaction rate coefficient
  • t tempering time (seconds)
  • N time index
  • A vibration factor term
  • Q activation energy
  • R gas constant
  • T tempering Tempering temperature (K)
  • M Hardness after tempering
  • ⁇ Hardness after quenching
  • ⁇ Raw material hardness
  • the hardness M and the raw material hardness M after quenching in the formula (10) can be measured.
  • N, A, and Q are experiments
  • the tempering time t can be calculated by Equation (10) by substituting the value of the tempering temperature T.
  • the timing at which the workpiece should be cooled can be determined by adjusting the tempering time t based on the equation (10).
  • Expression (10) is a relational expression between the heat treatment temperature and the retention time with respect to the standard quality (hardness) of the workpiece, and can be used effectively regardless of the shape of the rolling bearing outer ring 201.
  • the horizontal axis represents the tempering temperature (° C) and the vertical axis represents the holding time (seconds).
  • Region A is a range of HRC62 or higher
  • region B is a range of HRC58 or lower
  • region C is a range of HRC58-62.
  • the condition diagram shown in Fig. 23 can be created based on Equation (10) for obtaining the tempering time t. wear.
  • Equation (10) for obtaining the tempering time t. wear.
  • the higher the tempering temperature the shorter the tempering becomes possible. For this reason, a higher tempering temperature is desirable from the viewpoint of reducing the heat treatment time.
  • the tempering temperature can be determined in terms of the balance between heat treatment time and tempering unevenness.
  • the tempering conditions are input to a tempering temperature adjusting device 214 such as a personal computer with reference to FIG.
  • the tempering temperature adjusting device 214 is connected to the tempering temperature control temperature measuring device 213 and the tempering heating device 212. Based on the temperature information from the tempering temperature control temperature measuring device 213, the temperature is controlled by PID control. A control signal is output to the tempering heating device 212 to control the temperature transition of the rolling bearing outer ring 201.
  • the temperature information of the tempering end timing control temperature measuring device 215 is taken into the tempering end timing adjusting device 216 such as a personal computer, and it is judged from the temperature transition whether the heating is sufficient, Adjust the timing to be cooled.
  • the temperature transition is shown with time t on the horizontal axis and temperature T on the vertical axis.
  • the upper right figure shows an enlarged view of the area j8 in the upper left graph.
  • the lower part shows the formula for integrating the temperature transition force of the hardness M after tempering.
  • the temperature information from the tempering end timing control temperature measuring device 215 changes every moment, so the value of M (hardness after tempering) is calculated as t *. It is desirable to calculate by integrating as shown in FIG. When the condition that the hardness after tempering becomes the target hardness is satisfied, the rolling bearing outer ring 201 is cooled by the tempering end device 217. Note that the tempering temperature adjusting device 214 and the tempering end timing adjusting device 216 are also used as the same personal computer.
  • FIG. 25 is a schematic cross-sectional view showing a configuration of a rolling bearing outer ring as a high-frequency heat-treated product in the third embodiment which is an embodiment of the present invention.
  • the configuration of the rolling bearing outer ring in the third embodiment will be described.
  • rolling bearing outer ring 3 as the high frequency heat treatment product in the third embodiment 01 has an annular shape.
  • the rolling bearing outer ring 301 has a rolling surface 301C for rolling while the balls, rollers, etc., as rolling elements are in contact with the inner peripheral surface 301B, and is also in contact with other members. It has an outer peripheral surface 301A for holding the outer ring against the other members.
  • the rolling bearing outer ring 301 preferably has a hardness of 58 HRC or more from the viewpoint of rolling fatigue strength and rigidity. From the viewpoint of dimensional stability, the retained austenite content is preferably suppressed to 12% by volume or less.
  • the rolling bearing outer ring 301 is manufactured by heat treatment using the high-frequency heat treatment method in one embodiment of the present invention described below, a high-frequency heat-treated product with reduced manufacturing cost and stable quality is provided. It has become.
  • induction hardening apparatus 391 in Embodiment 3 is an induction heat treatment according to the present invention in which an object to be treated (for example, rolling bearing outer ring 301) is quenched and hardened by induction heating.
  • Induction hardening apparatus used in the method the temperature control device 350 for adjusting the temperature of the rolling bearing outer ring 301 as the object to be treated, and the timing at which the heated rolling bearing outer ring 301 should be cooled And a quenching control device 360 for adjusting the temperature.
  • the outer peripheral surface 301A and the inner peripheral surface 301B of the rolling bearing outer ring 301 are more resistant to oxidation than the rolling bearing outer ring 301 in the temperature range in which the rolling bearing outer ring 301 is heated, that is, in the quenching temperature.
  • a highly stable layer 309 is formed.
  • the temperature control device 350 acquires temperature data of the outer peripheral surface 301A that is considered to have the highest temperature due to high-frequency heating in the rolling bearing outer ring 301, and outputs temperature information based on the temperature data of the rolling bearing outer ring 301.
  • a first radiation thermometer 303 as a temperature control temperature measuring device, and connected to the first radiation thermometer 303, and controls the heating state of the object to be processed based on the temperature information from the first radiation thermometer 303.
  • a temperature control device 304 that outputs a temperature control signal for heating, and a heating device 302 that is connected to the temperature control device 304 and heats the rolling bearing outer ring 301 by high-frequency heating based on the temperature control signal from the temperature control device 304.
  • the heating device 302 includes, for example, an induction coil for flowing a high-frequency current, an induction coil And a power source that is connected to the coil and generates a high-frequency current.
  • the quenching control device 360 obtains temperature data of the inner peripheral surface 301B, which is considered to have the smallest temperature rise farthest from the outer peripheral surface 301A that is considered to have the highest temperature due to high-frequency heating, and 2nd radiation thermometer 305 as temperature measuring device for quenching that outputs temperature information based on temperature data of surface 301B, and connected to 2nd radiation thermometer 305, the temperature from 2nd radiation thermometer 305
  • a cooling timing adjusting device 306 that adjusts the heating time based on the information, determines the timing at which the rolling bearing outer ring 301 should be cooled, and outputs a cooling start signal, and is connected to the cooling timing adjusting device 306 and based on the cooling start signal
  • a cooling liquid injection device 307 as a cooling device for quenching and hardening the rolling bearing outer ring 301 by cooling the rolling bearing outer ring 301.
  • the temperature adjustment device 304 and the cooling timing adjustment device 306 are each a personal computer, for example, and have a configuration in which the temperature adjustment device 304 and the cooling timing adjustment device 306 are combined with one personal computer. May be.
  • the induction hardening method of the third embodiment is an induction heat treatment method in which the workpiece (rolling bearing outer ring 301) is heated and hardened by induction heating.
  • a surface stabilization step 311 is formed on the surface of the rolling bearing outer ring 301 in a temperature layer where the rolling bearing outer ring 301 is heated.
  • the surface stabilization step 311 includes a quench hardening step 310 in which the rolling bearing outer ring 301 on which the stabilization layer 309 is formed is quenched and hardened.
  • the quench hardening process 310 includes a temperature control process 320 in which the temperature of the rolling bearing outer ring 301 on which the stable layer 309 is formed is adjusted, and a timing at which the heated rolling bearing outer ring 301 is to be cooled. And a quench control step 330 in which the rolling bearing outer ring 301 is cooled.
  • the temperature control step 320 includes a temperature control temperature measurement step 323 in which the surface temperature of the stable layer 309 formed on the outer peripheral surface 301A of the rolling bearing outer ring 301 is measured by the first radiation thermometer 303, Rolling bearing based on temperature information measured in temperature measurement process 323 A temperature adjustment step 324 in which a temperature control signal for controlling the heating state of the outer ring 301 is output; and a heating step 322 in which the rolling bearing outer ring 301 is heated by high-frequency heating based on the temperature control signal.
  • the quenching control step 330 is a quenching temperature measurement step 335 in which the surface temperature of the stable layer 309 formed on the inner peripheral surface 301B of the rolling bearing outer ring 301 is measured by the second radiation thermometer 305. And a cooling timing adjusting step 336 in which the heating time is adjusted based on the temperature information measured in the quenching temperature measuring step 335, the timing at which the rolling bearing outer ring 301 should be cooled is determined, and a cooling start signal is output. And a cooling step 337 in which the rolling bearing outer ring 301 is quenched and hardened by cooling the rolling bearing outer ring 301 based on the cooling start signal.
  • the induction hardening method according to the third embodiment is performed by temperature control and is easy to determine the conditions for heat treatment. Therefore, the manufacturing cost of the rolling bearing outer ring 301 can be suppressed and the quality can be stabilized. It is pretty.
  • the black body paint is applied to the surface of the rolling bearing outer ring 301, so that the black body paint layer as the above-described stability layer 309 is formed. Good.
  • an iron oxide layer may be formed instead of the black body paint layer. This iron oxide layer may be formed, for example, by thermally oxidizing the surface of the rolling bearing outer ring 301, or may be formed by immersing the rolling bearing outer ring 301 in an acidic solution.
  • the hardness after tempering when tempering at 180 ° C is strength strength of HRC58 or higher (HV653 or higher), and the amount of retained austenite is 1 from the viewpoint of dimensional stability.
  • the standard value is set to 2% by volume or less.
  • the target heat treatment conditions condition of heating temperature and heating time in quenching.
  • the hardness of the SUJ2 rolling bearing outer ring increases as the quenching temperature and holding time increase. It becomes easy to satisfy the case.
  • the amount of austenite becomes difficult to meet the specifications as the quenching temperature and holding time increase.
  • it is easier to control the heat treatment quality by setting conditions at a relatively low temperature for a long time.
  • the holding time for ensuring the heat treatment quality standard is 15 seconds or more, but if it is kept for 17 seconds or more, the standard cannot be satisfied.
  • the holding time for ensuring the heat treatment quality is 20 seconds or more, and the standard can be satisfied up to 60 seconds.
  • FIG. 13 is a TTA diagram related to SUJ2. If a TTA diagram corresponding to the force material can be created, the heat treatment conditions may be determined according to the diagram.
  • the high-frequency heat treatment method 3 can be used regardless of the type of material.
  • the heat treatment conditions are input to temperature control device 304 such as a personal computer.
  • the temperature adjustment device 304 is connected to the first radiation thermometer 303 and the heating device 302. Based on the temperature information from the first radiation thermometer 303, the temperature control signal is transmitted by P ID (Proportional Integral Differential) control.
  • P ID Proportional Integral Differential
  • the temperature can be output to the heating device 302, and the temperature transition of the outer peripheral surface 301A, which is the temperature measuring unit of the first radiation thermometer 303, can be controlled.
  • the outer peripheral surface 301A is the part where the magnetic flux penetrates most in the rolling bearing outer ring 301 and the temperature rises most due to high frequency heating.
  • the temperature measurement data of the second radiation thermometer 305 is taken into the cooling timing adjustment device 306 such as a personal computer, and the temperature transition force is judged whether the heating is sufficient and the cooling timing is adjusted. . Judgment of the cooling timing is made based on whether or not the temperature transition of the inner peripheral surface 301B, which is the temperature measuring section of the second radiation thermometer 303, is within the specifications on the TTA diagram.
  • the inner peripheral surface 301B is a part where the magnetic flux intrudes most in the rolling bearing outer ring 301 and the temperature rise due to high frequency heating is the smallest.
  • the temperature adjustment device 304 and the cooling timing adjustment device 306 can be combined with the same personal computer. I'll do it with you.
  • equations (4) and (5) can be used, but preferably, equations (4) and (5) are used, which are obtained by correcting equation (3) in consideration of the fact that the temperature of the workpiece changes every moment.
  • D diffusion constant of carbon in steel
  • t retention time (seconds)
  • A correction factor
  • the value of the correction coefficient A is a value obtained by the following equation (6).
  • Equation (4) is an equation that calculates the diffusion length D of carbon when the value of C in Equation (6) becomes C.
  • thermodynamic equilibrium calculation it can be determined by thermodynamic equilibrium calculation. Cooling is performed when the value of carbon diffusion length D in equation (4) reaches a certain value (D *).
  • the temperature measuring section of the second radiation thermometer 305 does not necessarily have to be one place. By using a plurality of temperature measuring sections, it is possible to ensure heat treatment quality at a plurality of sites.
  • the temperature measurement part for determining the cooling timing (that is, inner peripheral surface 301B which is the temperature measurement part of second radiation thermometer 305) is determined. Since the temperature changes from moment to moment, the value of correction D (corrected D in equation (4), hereinafter simply referred to as D) ep ep ep must be integrated as D ⁇ D ⁇ D, as shown in Figure 14. is there. Rolling axis e l ep2 epn
  • the quenching control side (inner peripheral surface 301B side) is delayed compared to the temperature control side because the magnetic flux entry is less than the temperature control side (outer peripheral surface 301A side). Temperature rises. Normally, when the temperature exceeds 727 ° C, iron austenite begins, but when the rate of temperature rise is fast, the heating transformation temperature of iron changes. Therefore, the temperature for calculating the diffusion length The degree must be changed by the heating rate.
  • the temperature for calculating the diffusion length is preferably changed as appropriate depending on the type of the apparatus and object to be processed.
  • the diffusion length D is calculated using the formula in the figure.
  • the viewpoint power of reducing the heat treatment time is also desirable. However, from the standpoint of stabilizing quality, it is desirable to set a value that is somewhat safe.
  • the value of * is considered to be desirable to be 0.015mm or less.
  • D * is set to 0.015 mm, and D accumulated as described above becomes 0.015 mm ep epn
  • a cooling start signal is output from the cooling timing adjustment device 306 to the coolant injection device 307, and based on this, the coolant injection device 307 moves the rolling bearing outer ring 301 from a temperature higher than the A point to a temperature lower than the M point.
  • the rolling bearing outer ring 301 is quenched by cooling to the temperature.
  • the high-frequency heat treatment method, high-frequency heat treatment apparatus, and high-frequency heat treatment product in the modification of the third embodiment basically have the same configuration as that of the third embodiment described above.
  • the following equation (7) and equation (5) are used to determine whether the temperature transition of the inner peripheral surface 301B of the rolling S bearing outer ring 301 is within the standard on the TTA diagram in determining the cooling timing. It is different in point.
  • a method is used to determine whether the temperature transition of the inner peripheral surface 301B of the rolling bearing outer ring 301 falls within the standard on the TTA diagram, using Equation (7) and Equation (5). explain.
  • D Carbon diffusion constant in steel
  • C Carbon concentration (% by mass)
  • t Time (seconds)
  • X Distance
  • D D exp (—QZRT)
  • Q Activity energy
  • R Gas constant
  • T Absolute temperature
  • Cooling timing is determined by solving Equation (8) under certain boundary conditions and determining whether the solid solution state of carbon in the material satisfies a predetermined condition.
  • the boundary conditions are, for example, iron carbide (cementite; Fe C) and the base material in the steel constituting the rolling bearing outer ring 301 during heating.
  • the carbon solid solution concentration at a certain temperature can be given under the assumption that the solid solubility of carbon at that temperature is equal.
  • the solute carbon concentration is lowest at the position of 0.006 mm), and as the time passes, the solute carbon concentration increases as a whole and the central position And the difference between both ends (the interface between Fe C and the substrate) tends to be small.
  • the cooling start signal in the cooling timing adjustment step 336 is output when, for example, the inner peripheral surface 301B of the rolling bearing outer ring 301 satisfies the solute carbon concentration condition as the quenching condition described above at the center position. be able to.
  • the distance between two boundary points can be changed as appropriate depending on the structure and material before quenching of the workpiece.
  • the determination of the cooling timing in the present modification is performed as follows, for example.
  • the temperature on the quenching control side is measured by the second radiation thermometer 305 (Step A), and the carbon content at the boundary is calculated from the measured temperature (Step B).
  • Eq. (8) is calculated by applying the boundary carbon value to the boundary condition of Eq. (8) (Step C).
  • Step D it is possible to calculate the solid solution carbon concentration distribution as shown in Fig. 17 to Fig. 19 (Step D). From the obtained solute carbon concentration distribution, it is confirmed whether the carbon concentration at the center position of the solute carbon concentration distribution has reached a predetermined carbon concentration (eg, 0.6 to 0.8 mass%) (step E). If the carbon concentration at the center has reached the specified carbon concentration, start cooling ( Step F), if not, cooling is not started and heating is continued and the process returns to Step A again.
  • a predetermined carbon concentration eg, 0.6 to 0.8 mass%
  • equation (8) in step C above can be solved by the difference method as follows.
  • the carbon concentration at both ends of the carbon distribution in Figs. 17 to 19 is the carbon concentration at the carbide substrate interface. Therefore, carbon is supplied from this position to the substrate at a certain concentration (solid solubility of carbon).
  • C binding is located at the interface between carbide and substrate.
  • the formula power of solid solubility can also give the value of carbon concentration. As a result, there are five simultaneous equations and five unknowns, so the values of C, C, C, C, and C can be obtained.
  • the amount of retained austenite on the temperature control side is estimated from the solid solution state of the carbon on the temperature control side by performing the above calculation of the solid solution carbon concentration not only on the quenching control side but also on the temperature control side. be able to.
  • the value of the solute carbon concentration is generally higher on the temperature control side than on the quenching control side. This is because in the rolling bearing outer ring 301, the temperature on the temperature control side is higher than that on the quenching control side near the induction coil included in the heating device 302.
  • the starting temperature of the calculation of the solid solution carbon concentration that is, the starting temperature of the solid solution of carbon in the substrate. The determination method will be described below.
  • the heating transformation point A increases from 727 ° C to 950 ° C.
  • the heating transformation point A is determined from the above, and based on the heating transformation point A, the solute carbon concentration is
  • Calculation start temperature (carbon solid solution start temperature) can be determined.
  • heating on the temperature control side is performed rapidly, so that the rate of temperature increase on the quenching control side is also increased, and the heating transformation point is increased.
  • the temperature control device 304 controls the heating so that the rate of temperature increase becomes slow.
  • the rate of temperature increase on the quenching control side also becomes slow, and the heating transformation point A decreases.
  • the heating transformation point A becomes the quench control.
  • the carbon concentration at the center position of the distribution of the solute carbon concentration exceeds a predetermined carbon concentration (for example, 0.6 to 0.8 mass%).
  • a predetermined carbon concentration for example, 0.6 to 0.8 mass%.
  • induction hardening apparatus 392 in the fourth embodiment has basically the same configuration as induction hardening apparatus 391 in the third embodiment.
  • the induction hardening apparatus 392 in the embodiment 4 is connected to the heating apparatus 302, the temperature adjustment apparatus 304, and the cooling timing adjustment apparatus 306, and stores the transition data of the power output and the cooling timing data as process data. It is different from the induction hardening apparatus 391 of Embodiment 3 in that the storage apparatus 370 is provided.
  • the induction hardening method in the fourth embodiment is an induction heat treatment method in which a workpiece (for example, the rolling bearing outer ring 301) is heated and hardened by induction heating.
  • a workpiece for example, the rolling bearing outer ring 301
  • the data acquisition process, the storage process, the confirmation process, and the mass production process are provided.
  • the validity of the transition data of the power output and the cooling timing data is confirmed based on the material data of the rolling bearing outer ring 301 that has been hardened and hardened in the data acquisition process. That is, for example, the temperature transition data of the object to be processed in the data acquisition process is stored, and the stored temperature transition data is analyzed to determine whether or not there is an influence of disturbance, and is stored in the storage process. The validity of the power output transition data and cooling timing data, which are the process data, is confirmed. In addition, the material data of the sample of the rolling bearing outer ring 301 that has been actually heat-treated may be actually obtained by experiments, and the validity of the transition data of the power output and the cooling timing data may be confirmed.
  • the stored temperature transition data force can be determined whether there is a disturbance or not. is there. For example, if there is a discontinuous area in the temperature transition data, it can be determined that there was a disturbance.
  • a contact or non-contact thermometer that measures the temperature of the same part can be provided, and the presence or absence of disturbance can be determined based on the consistency of both data. As a specific judgment method, for example, when the difference between the two data power temperatures is 5% or more, it can be judged that there is a disturbance.
  • the disturbance can be determined by the operator confirming the temperature transition data, but can also be performed by another automated device. Specifically, for example, when the differential value of the temperature transition of the stored temperature transition data is 1000 ° CZ seconds or more or -1000 ° CZ seconds or less, there is a method of determining that there is a disturbance, or the same as described above. A thermometer that measures the temperature of the part is provided, and there is a means to judge that there is a disturbance when a difference of 5% or more occurs between the two data.
  • the rolling bearing outer ring 301 is subjected to high-frequency quenching according to the power output transition data and the cooling timing data that are stored in the storage process and validated in the confirmation process.
  • the quench hardening in the data acquisition process is the high frequency of the present invention. This is performed by a wave heat treatment method, for example, the induction hardening method of the third embodiment.
  • the process data can be obtained simply by quenching and hardening the rolling bearing outer ring 30 1 as the object to be processed by the induction hardening method in Embodiment 4, thereby making it possible to control the temperature and to easily determine the conditions for the heat treatment.
  • the influence of disturbance on the workpiece is further suppressed, and the quality of the workpiece (rolling bearing outer ring 301) is stabilized.
  • the rolling bearing outer ring 301 as the induction-hardened product in the fourth embodiment which has been hardened by the induction hardening method in the fourth embodiment, is a low-frequency and more stable high-frequency product. It is hardened.
  • FIG. 30 the data flow in the data acquisition process is a solid arrow, the data flow in the storage process is a broken arrow, the data flow in the confirmation process is a double dashed arrow, and the data flow in the mass production process is a double solid line. It is displayed with an arrow.
  • the data flow in each step of induction hardening according to the fourth embodiment will be described.
  • the temperature data of the sample of the rolling bearing outer ring 301 as the workpiece measured by the temperature control temperature measuring device is Sent to temperature controller 304.
  • the target heating temperature of the rolling bearing outer ring 301 and the obtained temperature data of the sample of the rolling bearing outer ring 301 are determined, and the necessary power output is determined, and the power output is commanded to the power supply of the heating device 302.
  • the power source that has received the command outputs power to the induction coil of the heating device 302, and the sample of the rolling bearing outer ring 301 is heated to a target temperature.
  • the temperature data of the sample of the rolling bearing outer ring 301 measured by the quenching temperature measuring device is sent to the cooling timing adjusting device 306.
  • the cooling timing adjusting device 306 determines the cooling timing from the acquired temperature and calorie heat time of the sample of the rolling bearing outer ring 301 and commands the cooling device such as the coolant injection device 307 to start cooling.
  • the sample of the rolling bearing outer ring 301 is quenched and hardened by hardening.
  • the heating history of the sample of the rolling bearing outer ring 301 is clear. Therefore, as long as the temperature data is accurate, appropriate heat treatment is performed, and the rolling bearing outer ring 301 having the desired quality is obtained.
  • the temperature data acquired by the temperature adjustment device 304 and the cooling timing adjustment device 306 in the data acquisition step is stored in the storage device 370 as temperature transition data.
  • the power supply output from the power supply of the heating device 302 to the induction coil is stored in the storage device 370 as the power output transition data.
  • the timing of the cooling start command output from the cooling timing adjusting device 310 to the cooling device such as the coolant injection device 307 is stored in the storage device 370 as cooling timing data.
  • the cooling timing is stored as, for example, the time from the start of heating.
  • thermometers capable of measuring the same part as the first radiation thermometer 303 and the second radiation thermometer 305 are provided, and the temperature of the part is measured. By comparing the temperature measurement data with the temperature transition data measured by the first radiation thermometer 303 and the second radiation thermometer 305 and stored in the storage device 370, the presence or absence of disturbance is determined.
  • the rolling bearing outer ring 301 is heated and hardened based on the power output transition data and the cooling timing data that are stored in the storage process and validated in the confirmation process. At this time, this mass production process is not performed based on real-time temperature data from the first radiation thermometer 303 and the second radiation thermometer 305, which may cause disturbance, and the validity of the power supply output has been confirmed. It is implemented by power control based on transition data and cooling timing data. Therefore, the rolling bearing outer ring 301 having a stable quality can be obtained.
  • the storage device 370 may be installed as an independent device, but for example, a personal computer having a storage unit such as a node disk may also be used as a device such as the temperature adjustment device 304 and the cooling timing adjustment device 306. May be installed.
  • each step of the induction hardening method of the present embodiment can be performed by using a personal computer as a control device, for example, and operating the personal computer with one or more programs corresponding to each step. it can.
  • a personal computer as a control device, for example, and operating the personal computer with one or more programs corresponding to each step. it can.
  • induction tempering apparatus 393 is a high-frequency tempering apparatus according to the present invention that performs tempering by heating an object to be treated (for example, rolling bearing outer ring 301) by induction heating.
  • the outer peripheral surface 301A and the inner peripheral surface 301B of the rolling bearing outer ring 301 are more resistant to oxidation than the rolling bearing outer ring 301 in the temperature range in which the rolling bearing outer ring 301 is heated, that is, the tempering temperature.
  • a high stability layer 309 is formed.
  • the temperature control device 351 obtains temperature data of the outer peripheral surface 301A that is considered to have the highest temperature due to high-frequency heating in the rolling bearing outer ring 301, and outputs temperature information based on the temperature data of the rolling bearing outer ring 301.
  • the first radiation thermometer 313 as a temperature control temperature measuring device and the first radiation thermometer 313 are connected to control the heating state of the object to be processed based on the temperature information from the first radiation thermometer 313.
  • a temperature control device 314 that outputs a temperature control signal for heating, and a heating device 312 that is connected to the temperature control device 314 and heats the rolling bearing outer ring 301 by high-frequency heating based on the temperature control signal from the temperature control device 314. Contains.
  • the heating device 312 has, for example, an induction coil for flowing a high-frequency current, and a power source that is connected to the induction coil and generates a high-frequency current.
  • the tempering control device 361 obtains the temperature data of the inner peripheral surface 301B, which is considered to have the smallest temperature rise farthest from the outer peripheral surface 301A, which is considered to have the highest temperature due to high-frequency heating.
  • a second radiant thermometer 315 that outputs temperature information based on the temperature data of surface 301B and a second radiant thermometer 315 connected to the second radiant thermometer 315. Based on the information, the heating time is adjusted, the timing at which the rolling bearing outer ring 301 should be cooled is determined and a cooling start signal is output, and the cooling timing adjusting device 316 is connected to the cooling timing adjusting device 316 and is based on the cooling start signal.
  • a cooling fluid injection device 317 as a cooling device that terminates tempering of the rolling bearing outer ring 301 by cooling the rolling bearing outer ring 301 is included.
  • the temperature adjustment device 314 and the cooling timing adjustment device 316 are each a personal computer, for example, and each personal computer is configured to serve as both the temperature adjustment device 314 and the cooling timing adjustment device 316. May be.
  • the induction tempering method of the fifth embodiment is an induction heat treatment in which an object to be treated (for example, the rolling bearing outer ring 301) is heated and tempered by induction heating.
  • a surface stabilizing step 311 in which a stabilizing layer 309 having higher oxidation resistance than the rolling bearing outer ring 301 is formed on the surface of the rolling bearing outer ring 301, and a stable layer in the surface stabilizing step.
  • a tempering step 410 in which the rolling bearing outer ring 301 formed with 309 is heated and tempered.
  • the temperature control step 420 in which the temperature of the rolling bearing outer ring 301 is adjusted, the timing at which the heating of the rolling bearing outer ring 301 should be finished, are determined, and the rolling bearing outer ring 301 is cooled. And tempering control step 430.
  • the temperature control step 420 includes a temperature control step 423 in which the surface temperature of the stable layer 309 formed on the surface of the rolling bearing outer ring 301 is measured by a radiation thermometer, and a temperature control temperature measurement step 423.
  • a temperature adjustment step 424 in which a temperature control signal for controlling the heating state of the rolling bearing outer ring 301 is output based on the temperature information measured in step 423, and a rolling bearing outer ring by high-frequency heating based on the temperature control signal.
  • the tempering control process 430 includes a tempering temperature measurement process 435 in which the surface temperature of the stable layer 309 formed on the surface of the rolling bearing outer ring 301 is measured by a radiation thermometer, and a tempering measurement process 430.
  • a cooling timing adjustment step 436 in which the heating time is adjusted based on the temperature information measured in the temperature range 435, the timing at which the rolling bearing outer ring 301 should be cooled is determined, and a cooling start signal is output.
  • a cooling step 437 in which tempering of the rolling bearing outer ring 301 is completed by cooling the rolling bearing outer ring 301 based on the start signal.
  • the induction tempering method in the fifth embodiment is performed by temperature control, and it is easy to determine the conditions for heat treatment. Therefore, the manufacturing cost of the rolling bearing outer ring 301 is suppressed, and the quality is reduced. Can be determined.
  • the induction tempering method of the fifth embodiment for example, the workpiece having the same configuration as the rolling bearing outer ring 301 of the third embodiment described with reference to FIG. Tempering can be carried out.
  • the rolling bearing outer ring 301 as the high frequency heat-treated product in the fifth embodiment which is one embodiment of the present invention, is a high-frequency heat treated product with reduced manufacturing cost and stable quality.
  • a black body paint is applied to the surface of the rolling bearing outer ring 301 so that the black body as the stabilization layer 309 described above is applied.
  • a coating layer may be formed, or an iron oxide layer may be formed instead of the black body paint layer.
  • This acid iron layer may be formed by, for example, the surface of the rolling bearing outer ring 301 being thermally oxidized, or may be formed by immersing the rolling bearing outer ring 301 in an acidic solution. Good.
  • the high-frequency heat treatment method of the fifth embodiment will be specifically described taking a rolling bearing outer ring 301 made of SUJ2 as an example.
  • the outer ring 301 of the rolling bearing is quenched by being rapidly cooled from 850 ° C. in an RX gas atmosphere furnace.
  • the heat treatment standard of the workpiece after tempering is set to hardness HRC58 or more and HRC62 or less.
  • X rate of change of mechanical properties
  • k reaction rate coefficient
  • t tempering time (seconds)
  • N time index
  • A vibration factor term
  • Q activation energy
  • R gas constant
  • T tempering Tempering temperature (K)
  • M Hardness after tempering
  • ⁇ Hardness after quenching
  • ⁇ Raw material hardness
  • the hardness M and the raw material hardness M after quenching in the formula (10) can be measured.
  • N, A, and Q are experiments
  • the tempering time t can be calculated by Equation (10) by substituting the value of the tempering temperature T.
  • tempering is performed based on the equation (10).
  • the time t can be adjusted.
  • Expression (10) is a relational expression between the heat treatment temperature and the retention time with respect to the standard quality (hardness) of the workpiece, and can be used effectively regardless of the shape of the rolling bearing outer ring 301.
  • the condition diagram shown in FIG. 23 can be prepared based on the equation (10) for obtaining the tempering time t.
  • the higher the tempering temperature the shorter the tempering becomes possible. For this reason, a higher tempering temperature is desirable from the viewpoint of reducing the heat treatment time.
  • the tempering temperature can be determined in terms of the balance between heat treatment time and tempering unevenness.
  • the tempering conditions are input to temperature control device 314 such as a personal computer.
  • the temperature adjustment device 314 is connected to the first radiation thermometer 313 and the heating device 312, and based on the temperature information from the first radiation thermometer 313, outputs a temperature control signal to the heating device 312 by PID control. Controls temperature transition of rolling bearing outer ring 301.
  • the temperature information of the second radiation thermometer 315 is taken into a cooling timing adjustment device 316 such as a personal computer, and it is judged whether the heating is sufficient from the temperature transition, and the tempering end time is adjusted.
  • the temperature information from the second radiation thermometer 315 changes every moment.
  • the value of M (hardness after tempering) should be calculated by integrating t * as shown in Fig. 24.
  • the rolling bearing outer ring 301 is cooled by the coolant injection device 317.
  • the temperature adjusting device 314 and the cooling timing adjusting device 316 can also be used as the same personal computer.
  • the heat treatment apparatus of the fifth embodiment has basically the same configuration as the heat treatment apparatus of the third embodiment described above. Therefore, for example, by using a personal computer as a control device and using a program corresponding to the desired heat treatment, the induction hardening device and the induction tempering device can be combined.
  • induction tempering apparatus 394 in the sixth embodiment has basically the same configuration as induction tempering apparatus 393 in the fifth embodiment.
  • the induction tempering apparatus 394 in Embodiment 6 is connected to the heating apparatus 312, the temperature adjustment apparatus 314, and the cooling timing adjustment apparatus 316 and stores the power output transition data and the cooling timing data as process data. This is different from the induction tempering apparatus 393 of Embodiment 5 in that the storage apparatus 371 is provided.
  • the induction tempering method in the sixth embodiment is an induction heat treatment method in which an object to be treated (for example, the rolling bearing outer ring 301) is heated and tempered by induction heating. Therefore, it has a data acquisition process, a storage process, a confirmation process, and a mass production process.
  • the process data is acquired by heating and tempering the sample of the rolling bearing outer ring 301.
  • the memory process in order to heat the sample of the rolling bearing outer ring 301 in the data acquisition process, the transitional data of the power output output to the induction coil and the power supply power for high-frequency heating and the cooling timing of the sample of the rolling bearing outer ring 301 are specified. And cooling timing data for the storage are stored as process data.
  • the validity of the transition data of the power output and the cooling timing data is confirmed based on the material data of the rolling bearing outer ring 301 tempered in the data acquisition process. That is, for example, the temperature transition data of the object to be processed in the data acquisition process is stored, and the stored temperature transition data is analyzed to determine the presence or absence of the influence of the disturbance. The validity of the transition data of the power output and the cooling timing data, which are the processed process data, is confirmed. It should be noted that the material data of the sample of the rolling bearing outer ring 301 that has been actually heat-treated may be actually obtained through experiments to confirm the validity of the power output transition data and the cooling timing data.
  • the disturbance can be determined by the operator confirming the temperature transition data, but can also be performed by another automated device. Specifically, for example, when the differential value of the temperature transition of the stored temperature transition data is 1000 ° CZ seconds or more or -1000 ° CZ seconds or less, there is a method of determining that there is a disturbance, or the same as described above. A thermometer that measures the temperature of the part is provided, and there is a means to judge that there is a disturbance when a difference of 5% or more occurs between the two data.
  • high-frequency tempering of the rolling bearing outer ring 301 is performed in accordance with the transition data and cooling timing data of the power output stored in the storage process and validated in the confirmation process.
  • the tempering in the data acquisition step is performed by the high frequency heat treatment method of the present invention, for example, the high frequency heat treatment method of the fifth embodiment.
  • the rolling bearing outer ring 301 as the induction tempered product in the sixth embodiment tempered by the induction tempering method in the sixth embodiment is reduced in price and further improved in quality. It is a tempered product.
  • FIG. 35 the data flow in the data acquisition process is a solid arrow, the data flow in the storage process is a broken arrow, the data flow in the confirmation process is a double dashed arrow, and the data flow in the mass production process is a double solid line. It is displayed with an arrow.
  • FIG. 35 a data flow in each step of induction tempering according to the sixth embodiment will be described.
  • the data is sent to temperature controller 314.
  • the target heating temperature of the rolling bearing outer ring 301 and the obtained temperature data of the sample of the rolling bearing outer ring 301 are judged, and the necessary power output is determined, and the power output of the heating device 312 is commanded.
  • the power source that receives the command outputs power to the induction coil of the heating device 312 and the sample of the rolling bearing outer ring 301 is heated to a target temperature.
  • the temperature data of the sample of the rolling bearing outer ring 301 measured by the tempering temperature measuring device is sent to the cooling timing adjusting device 316.
  • the cooling timing adjusting device 316 determines the cooling timing from the obtained temperature and calorie heat time of the sample of the rolling bearing outer ring 301 and commands a cooling device such as a coolant injection device to start cooling. Thereby, the sample of the rolling bearing outer ring 301 is cooled, and tempering is completed.
  • this data acquisition process is performed by temperature control, the heating history of the sample of the rolling bearing outer ring 301 is clear. Therefore, as long as the temperature data is accurate, an appropriate heat treatment is performed, and the rolling bearing outer ring 301 having the desired quality is obtained. As a result, it is easy to determine conditions that do not need to be determined while checking the quality of the workpiece.
  • a stabilization layer is formed on the surface of the workpiece, the accuracy of temperature measurement with a radiation thermometer is increasing.
  • the temperature data acquired by the temperature adjustment device 314 and the cooling timing adjustment device 316 in the data acquisition step is stored in the storage device 370 as temperature transition data.
  • the power output output from the power supply of the heating device 312 to the induction coil is stored in the storage device 371 as the power output transition data.
  • the timing of the cooling start command output from the cooling timing adjusting device 316 to the cooling device such as the coolant injection device is stored in the storage device 371 as the cooling timing data.
  • the cooling timing is stored as the time from the start of heating, for example.
  • thermometers capable of measuring the same part as the first radiation thermometer 313 and the second radiation thermometer 315 are provided, and the temperature of the part is measured. By comparing this temperature measurement data with the temperature transition data measured by the first radiation thermometer 313 and the second radiation thermometer 315 and stored in the storage device 371, the presence or absence of disturbance is determined.
  • the rolling bearing outer ring 301 is heated and tempered based on the transition data and cooling timing data of the power output stored in the storage process and validated in the confirmation process.
  • the mass production process is not performed based on the real-time temperature data from the first radiation thermometer 313 and the second radiation thermometer 315, which may cause disturbance, and the validity of the power output is confirmed. It is implemented by power control based on transition data and cooling timing data. Therefore, the rolling bearing outer ring 301 having a stable quality can be obtained.
  • the storage device 371 may be installed as an independent device.
  • a personal computer having a storage unit such as a node disk may be used as a device such as the temperature adjustment device 314 and the cooling timing adjustment device 316. May be installed.
  • each step of the induction tempering method of the present embodiment can be performed by using a personal computer as a control device, for example, and operating the personal computer with one or more programs corresponding to each step. it can.
  • induction hardening was performed by the induction hardening method of the present invention, and a test was performed to confirm the effectiveness.
  • the test procedure is as follows.
  • the target values for hardness and retained austenite were 58HRC (653HV) or more and 12% by volume or less, respectively. Table 1 shows the test results.
  • Example 2 of the present invention will be described below.
  • a test was conducted to confirm the effect of the surface stabilization process in the high-frequency heat treatment method of the present invention.
  • the test procedure is as follows.
  • JIS SUJ2 rolling bearing outer rings and JIS SUS440C rolling bearing outer rings were selected as objects to be tested. Then, the respective parts to be processed were measured with a radiation thermometer and a thermocouple while holding the objects to be processed at a temperature of 900 ° C. or higher. JIS SUS440C rolling bearing outer rings must be at the heating temperature before heating! It has excellent oxidation resistance and almost no change in emissivity! A similar test was performed after applying black body paint (Pyromark High Temperature Paint, manufactured by TE MPIL) on the surface.
  • black body paint Pant High Temperature Paint, manufactured by TE MPIL
  • the horizontal axis indicates the heating time
  • the vertical axis indicates the heating temperature
  • the solid line indicates the temperature measurement data of the radiation thermometer
  • the broken line indicates the temperature measurement data of the thermocouple.
  • the temperature measurement data of the radiation thermometer and the temperature measurement data of the thermocouple are measured in a short time from the start of heating, specifically about 15 seconds.
  • the ratio is almost constant. This is because in the case of a SUJ2 rolling bearing outer ring, an iron oxide layer is formed on the surface of the outer ring by thermal oxidation within a short time after the start of the heating described above. This is thought to be because the surface condition changed and became strong.
  • thermocouple temperature measurement data is almost horizontal when 170 seconds have elapsed from the start of heating. After that, the ratio between the temperature measurement data of the radiation thermometer and the temperature measurement data of the thermocouple is almost constant. This is because SUS440C has superior acid resistance compared to SUJ2, so it takes longer time to form the acid iron layer to the extent that the surface state does not change due to thermal oxidation. This is probably because of this. In other words, SUS440C needs to be held at 920 ° C for about 170 seconds in order for the iron oxide layer to be formed to such an extent that the surface state does not change.
  • the measurement accuracy of the radiation thermometer is improved by carrying out the surface stabilization process of the present invention.
  • a material with high acid resistance such as stainless steel (for example, SUS440 C, M50 It has been confirmed that it is possible to stabilize the quality of high-frequency heat-treated products composed of
  • the induction hardening method and the induction hardening apparatus of the present invention can be applied particularly advantageously to an induction hardening method and an induction hardening apparatus in which an object to be processed is quenched by induction heating.
  • the induction-hardened product of the present invention can be applied particularly advantageously to an induction-hardened product that is heated and hardened by induction heating.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Control Of Heat Treatment Processes (AREA)
  • Heat Treatment Of Articles (AREA)
  • General Induction Heating (AREA)

Abstract

La présente invention concerne un procédé de trempe haute fréquence (10) dans lequel il est possible de contrôler la température, d'effectuer facilement et efficacement une trempe et de conférer un traitement thermique souhaité de qualité sur une grande partie d'un ouvrage. Le procédé comprend une étape de contrôle de la température (20) et une étape de contrôle de la trempe (30). L'étape de contrôle de la température (20) comprend une étape de mesure de la température (23) destinée à contrôler la température, une étape de régulation de la température (24) et une étape de chauffage (22). L'étape de contrôle de la trempe (30) comprend une étape de mesure de la température (35), destinée à une trempe, dans laquelle on mesure les températures d'une partie de température élevée et d'une partie de température basse d'un ouvrage, une étape de régulation du temps de refroidissement (36) et une étape de refroidissement (37). Lors de l'étape de régulation du temps de refroidissement (36), le temps de chauffage est régulé de manière à permettre à l'historique de la température dans la partie de température élevée de satisfaire aux exigences relatives à l'historique de la température aboutissant à une quantité d'austénite résiduelle qui n'est pas supérieure à la limite supérieure souhaitée, et à l'historique de la température dans la partie de température basse de satisfaire aux exigences aboutissant à une dureté qui n'est pas inférieure à une limite inférieure souhaitée, et un signal de début de refroidissement est ainsi sorti.
PCT/JP2007/053033 2006-03-09 2007-02-20 Procede de trempe haute frequence, appareil de trempe haute frequence et produit d'une trempe haute frequence WO2007102306A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2006064463A JP2007239044A (ja) 2006-03-09 2006-03-09 高周波熱処理設備
JP2006-064463 2006-03-09
JP2006064453A JP2007239043A (ja) 2006-03-09 2006-03-09 高周波熱処理方法および高周波熱処理品
JP2006-064249 2006-03-09
JP2006064249A JP2007239039A (ja) 2006-03-09 2006-03-09 高周波焼入方法、高周波焼入設備および高周波焼入品
JP2006-064453 2006-03-09

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Publication number Priority date Publication date Assignee Title
EP2728965A1 (fr) * 2008-09-30 2014-05-07 Aktiebolaget SKF Chauffe roulements
WO2014069149A1 (fr) * 2012-10-31 2014-05-08 Ntn株式会社 Procédé de traitement thermique et procédé pour la fabrication d'une pièce de machine
CN106319168A (zh) * 2016-08-25 2017-01-11 江苏大学 一种可实现温度闭环控制的金属板料感应加热装置
CN114561513A (zh) * 2022-02-21 2022-05-31 郑州科创电子有限公司 一种淬火感应加热系统和方法

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JPH11293336A (ja) * 1998-04-14 1999-10-26 High Frequency Heattreat Co Ltd 高強度鋼の製造方法
JP2003213380A (ja) * 2002-01-22 2003-07-30 Nsk Ltd 転動装置
JP2005048292A (ja) * 1994-03-29 2005-02-24 Mazda Motor Corp 浸炭焼入れ方法
JP2005310645A (ja) * 2004-04-23 2005-11-04 Ntn Corp 高周波焼入装置

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JP2005048292A (ja) * 1994-03-29 2005-02-24 Mazda Motor Corp 浸炭焼入れ方法
JPH11293336A (ja) * 1998-04-14 1999-10-26 High Frequency Heattreat Co Ltd 高強度鋼の製造方法
JP2003213380A (ja) * 2002-01-22 2003-07-30 Nsk Ltd 転動装置
JP2005310645A (ja) * 2004-04-23 2005-11-04 Ntn Corp 高周波焼入装置

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2728965A1 (fr) * 2008-09-30 2014-05-07 Aktiebolaget SKF Chauffe roulements
WO2014069149A1 (fr) * 2012-10-31 2014-05-08 Ntn株式会社 Procédé de traitement thermique et procédé pour la fabrication d'une pièce de machine
JP2014088607A (ja) * 2012-10-31 2014-05-15 Ntn Corp 熱処理方法および機械部品の製造方法
EP2915886A4 (fr) * 2012-10-31 2016-06-29 Ntn Toyo Bearing Co Ltd Procédé de traitement thermique et procédé pour la fabrication d'une pièce de machine
US10161015B2 (en) 2012-10-31 2018-12-25 Ntn Corporation Heat treatment method and method of manufacturing machine part
CN106319168A (zh) * 2016-08-25 2017-01-11 江苏大学 一种可实现温度闭环控制的金属板料感应加热装置
CN106319168B (zh) * 2016-08-25 2018-06-01 江苏大学 一种可实现温度闭环控制的金属板料感应加热装置
CN114561513A (zh) * 2022-02-21 2022-05-31 郑州科创电子有限公司 一种淬火感应加热系统和方法

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