JP2007239039A - Induction-hardening method, induction-hardening facility and induction-hardened article - Google Patents

Induction-hardening method, induction-hardening facility and induction-hardened article Download PDF

Info

Publication number
JP2007239039A
JP2007239039A JP2006064249A JP2006064249A JP2007239039A JP 2007239039 A JP2007239039 A JP 2007239039A JP 2006064249 A JP2006064249 A JP 2006064249A JP 2006064249 A JP2006064249 A JP 2006064249A JP 2007239039 A JP2007239039 A JP 2007239039A
Authority
JP
Japan
Prior art keywords
temperature
processed
heating
cooling
induction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
JP2006064249A
Other languages
Japanese (ja)
Inventor
Takumi Fujita
工 藤田
Nobuyuki Suzuki
伸幸 鈴木
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NTN Corp
Original Assignee
NTN Corp
NTN Toyo Bearing Co Ltd
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
Application filed by NTN Corp, NTN Toyo Bearing Co Ltd filed Critical NTN Corp
Priority to JP2006064249A priority Critical patent/JP2007239039A/en
Priority to PCT/JP2007/053033 priority patent/WO2007102306A1/en
Publication of JP2007239039A publication Critical patent/JP2007239039A/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction-hardening method and an induction-hardening facility with which the temperature control can be easily obtained and the hardening can easily and efficiently be applied and also, a desired heat-treated quality in the wide range of a material to be treated can be given. <P>SOLUTION: The induction-hardening method 10 is provided with a temperature control process 20 and a hardening control process 30. The temperature control process 20 contains a temperature-measuring process 23 for temperature control, a temperature adjusting process 24 and a heating process 22. The hardening control process 30 contains a temperature measuring process 35 for hardening, measuring the high temperature part and the low temperature part in the material to be treated, a cooling timing adjusting process 36 and a cooling process 37. Then, in the cooling timing adjusting process 36, a cooling start signal is output when the temperature history in the high temperature part satisfies the condition in the temperature history so as to become the upper limit value or lower of the desired retained austenite quantity, and the temperature history in the low temperature part is adjusted to the heating time so as to satisfy the condition of the lower limit value or higher of the desired hardness. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は高周波焼入方法、高周波焼入設備および高周波焼入品に関し、より特定的には、高周波加熱により被処理物を加熱して焼入を行なう高周波焼入方法および高周波焼入設備、高周波加熱により加熱されて焼入れられた高周波焼入品に関するものである。   The present invention relates to an induction hardening method, an induction hardening equipment, and an induction hardening product, and more specifically, an induction hardening method, an induction hardening equipment, and an induction hardening method in which an object to be treated is heated by induction heating. The present invention relates to an induction-hardened product that has been heated and quenched by heating.

高周波焼入は、誘導コイルに高周波電流を流すことにより、誘導コイルに隣接してセットされた被処理物を誘導加熱し、被処理物の焼入を行なう熱処理方法である。この高周波焼入は、一般的に鋼の熱処理方法として採用されている浸炭焼入や光輝熱処理などに比べて、作業環境がクリーンであり、少量ロットの製品を短時間で効率よく処理できるといった点で有利である。そのため、高周波焼入方法や高周波焼入設備に関しては、被処理物の硬度の制御や、熱処理の効率向上を目的として多くの検討がなされ、種々の提案がなされている（たとえば特許文献１および２参照）。
特開２００４−３１５８５１号公報 特開２００４−２２５０８１号公報 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 has a cleaner working environment and can efficiently process a small lot of products in a short time compared to carburizing quenching and bright heat treatment, which are generally adopted as heat treatment methods for steel. Is advantageous. Therefore, regarding the induction hardening method and induction hardening equipment, many studies have been made for the purpose of controlling the hardness of the workpiece and improving the efficiency of heat treatment, and various proposals have been made (for example, Patent Documents 1 and 2). reference).
JP 2004-315851 A JP 2004-225081 A

高周波焼入においては、一般的な雰囲気炉のように炉内の雰囲気を介して被処理物が加熱される焼入方法とは異なり、被処理物が誘導加熱により直接加熱される。そのため、被処理物の温度を測定するためには、被処理物を直接測温する必要がある。しかし、高周波焼入設備には、被処理物を均一に加熱するため、被処理物を回転等させるための駆動機構が設けられている場合が多く、接触式の温度計の設置が困難である場合が多い。   In the induction hardening, unlike the quenching method in which the object to be processed is heated through the atmosphere in the furnace like a general atmosphere furnace, the object to be processed is directly heated by induction heating. Therefore, in order to measure the temperature of the workpiece, it is necessary to directly measure the temperature of the workpiece. However, induction hardening equipment is often provided with a drive mechanism for rotating the object to be processed to uniformly heat the object to be processed, and it is difficult to install a contact-type thermometer. There are many cases.

このように、高周波焼入においては被処理物の測温が容易ではなく、温度と時間との熱処理条件による熱処理の制御（温度制御）が難しい。そのため、一般に、高周波焼入においては、電力と時間との熱処理条件による熱処理の制御（電力制御）が採用される場合が多い。この電力制御による高周波焼入においては、被処理物に付与される加熱履歴が明確ではない。そのため、過去の生産実績や作業者の経験に基づいて仮の熱処理条件が設定され、被処理物のサンプルが実際に焼入されて当該サンプルの硬度、残留オーステナイト量などの熱処理品質が確認されることを繰返しつつ、試行錯誤により熱処理条件が設定されている。その結果、所望の熱処理品質を被処理物に付与するためには、被処理物の形状や大きさが変更されるたびに、熱処理品質を確認しながらの熱処理の試行錯誤を繰返して熱処理条件を設定する必要がある。このように、熱処理の条件出しに手間がかかるだけでなく、過去の生産実績の十分な蓄積や作業者の高周波焼入に関する十分な経験が必要となる点が高周波焼入の問題点となっている。   Thus, in induction hardening, it is not easy to measure the temperature of the workpiece, and it is difficult to control the heat treatment (temperature control) according to the heat treatment conditions of temperature and time. Therefore, in general, in the induction hardening, heat treatment control (power control) based on heat treatment conditions of electric power and time is often employed. In induction hardening by this power control, the heating history imparted to the workpiece is not clear. Therefore, provisional heat treatment conditions are set based on past production results and operator experience, and the sample of the workpiece is actually quenched to confirm the heat treatment quality such as hardness and residual austenite amount of the sample. While repeating this, heat treatment conditions are set by trial and error. As a result, in order to impart the desired heat treatment quality to the workpiece, every time the shape or size of the workpiece is changed, the heat treatment conditions are set by repeating trial and error of the heat treatment while checking the heat treatment quality. Must be set. In this way, not only is it time-consuming to determine the conditions for heat treatment, but also the problem of induction hardening is that sufficient accumulation of past production results and sufficient experience of induction hardening by workers are required. Yes.

また、高周波加熱においては、被処理物は、その全体が完全には均一に加熱されないため、被処理物の内部において温度分布が生じ、被処理物の広い範囲に所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することが難しいという問題点もあった。   In addition, in high-frequency heating, the entire object to be processed is not completely heated uniformly, so that a temperature distribution is generated inside the object to be processed, and a desired hardness and residual austenite are present in a wide range of the object to be processed. There is also a problem that it is difficult to impart heat treatment quality such as quantity.

そこで、本発明の目的は、温度制御を可能にし、熱処理の条件出しを容易に行なうことを可能にすることにより、過去の生産実績の蓄積が少ない場合や、経験の浅い作業者が熱処理の作業を行なう場合でも、容易にかつ効率よく実施することができるとともに、被処理物の広い範囲に所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することが可能な高周波焼入方法、および当該高周波焼入方法を実施するための高周波焼入設備を提供することである。また、本発明の他の目的は、製造コストが抑制され、品質の安定した高周波焼入品を提供することである。   Therefore, an object of the present invention is to enable temperature control and easily determine the conditions for heat treatment, so that the accumulation of past production results is small or an inexperienced worker can perform heat treatment work. Induction hardening method that can be easily and efficiently performed, and can impart heat treatment quality such as desired hardness and amount of retained austenite to a wide range of workpieces, and It is to provide an induction hardening facility for carrying out the induction hardening method. Another object of the present invention is to provide an induction-hardened product with reduced production cost and stable quality.

本発明に従った高周波焼入方法は、高周波加熱により被処理物の全体を加熱して焼入硬化する高周波焼入方法であって、被処理物の温度が調節される温度制御工程と、加熱された被処理物が冷却されるべきタイミングが決定されて、被処理物が冷却される焼入制御工程とを備えている。温度制御工程は、被処理物の温度が測定される温度制御用測温工程と、温度制御用測温工程において測定された温度の情報に基づき、被処理物の加熱状態を制御するための温度制御信号が出力される温度調節工程と、温度制御信号に基づいて、高周波加熱により被処理物が加熱される加熱工程とを含んでいる。   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, a temperature control step in which the temperature of the object to be processed is adjusted, and heating And a quenching control step in which a timing at which the processed object is to be cooled is determined, and the processed object is cooled. The temperature control process is a temperature control process for measuring the temperature of the object to be processed, and a temperature for controlling the heating state of the object to be processed based on the temperature information measured in the temperature control process for temperature control. It includes a temperature adjustment process in which a control signal is output and a heating process in which the workpiece is heated by high-frequency heating based on the temperature control signal.

焼入制御工程は、被処理物において、高周波加熱による温度の上昇が被処理物の内部よりも大きい表面の部位である高温部と、高周波加熱による温度の上昇が被処理物の内部よりも小さい表面の部位である低温部との温度が測定される焼入用測温工程と、焼入用測温工程において測定された温度の情報に基づき加熱時間が調節され、被処理物が冷却されるべきタイミングが決定されて冷却開始信号が出力される冷却タイミング調節工程と、冷却開始信号に基づいて、被処理物が冷却されることにより被処理物が焼入硬化される冷却工程とを含んでいる。   In the quenching control process, in the workpiece, a high temperature portion which is a surface portion where the temperature rise due to high frequency heating is larger than the inside of the workpiece, and the temperature rise due to high frequency heating is smaller than the inside of the workpiece. The temperature measurement process for quenching in which the temperature of the low temperature part, which is the surface part, is measured, and the heating time is adjusted based on the temperature information measured in the temperature measurement process for quenching, thereby cooling the workpiece. A cooling timing adjustment step in which a timing to be determined is determined and a cooling start signal is output, and a cooling step in which the workpiece is quenched and hardened by cooling the workpiece based on the cooling start signal. Yes.

そして、冷却タイミング調節工程においては、高温部における温度および加熱時間を含む温度履歴が、予め求められた所望の残留オーステナイト量の上限値以下の残留オーステナイト量が得られる温度履歴の条件を満たし、低温部における温度および加熱時間を含む温度履歴が、予め求められた所望の硬度の下限値以上の硬度が得られる温度履歴の条件を満たすように加熱時間が調節されて、冷却開始信号が出力される。   In the cooling timing adjustment step, the temperature history including the temperature in the high temperature part and the heating time satisfies the condition of the temperature history for obtaining the retained austenite amount equal to or lower than the upper limit value of the desired retained austenite amount obtained in advance. The heating time is adjusted so that the temperature history including the temperature and the heating time in the section satisfies the condition of the temperature history for obtaining a hardness equal to or higher than a predetermined lower limit of the desired hardness, and a cooling start signal is output. .

一般に、高周波焼入においては、まず熱処理条件として電力と時間とのパラメータからなる電源出力の推移（電源出力パターン）が、過去の熱処理の実績や作業者の経験に基づいて決定される（電力制御）。そして、熱処理条件は、被処理物の形状、大きさ、材質等を考慮しつつ電力と時間とを変化させて被処理物のサンプルを実際に熱処理して決定される。そのため、熱処理条件の決定に経験と手間が必要となる。また、鋼製品の焼入においては、被処理物を所定温度に所定時間以上保持した後、急冷する必要がある。しかし、上記方法（電力制御）では被処理物の加熱履歴を正確に把握することは困難である。そのため、熱処理条件を決定するためには、実際に熱処理を実施して得られた被処理物の硬度、残留オーステナイト量等の品質を調査する必要がある。   In general, in induction hardening, the transition of power output (power output pattern) consisting of parameters of power and time as heat treatment conditions is first 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. Further, in quenching of steel products, it is necessary to rapidly cool an object to be processed after it is kept at a predetermined temperature for a predetermined time. However, it is difficult to accurately grasp the heating history of the workpiece by the above method (power control). Therefore, in order to determine the heat treatment conditions, it is necessary to investigate the quality such as the hardness and the amount of retained austenite of the workpiece obtained by actually performing the heat treatment.

これに対し、本発明の高周波焼入方法では、温度制御工程および焼入タイミング制御工程により、温度と時間とをパラメータとして被処理物の加熱が制御される（温度制御）。そのため、被処理物の加熱履歴を正確に把握することが可能であり、被処理物に必要な加熱履歴を与えた後、急冷することで焼入を行なうことができる。   On the other hand, in the induction hardening method of the present invention, the heating of the workpiece is controlled by the temperature control process and the quenching timing control process using the temperature and time as parameters (temperature control). Therefore, it is possible to accurately grasp the heating history of the object to be processed, and quenching can be performed by quenching after giving the necessary heating history to the object to be processed.

ここで、被処理物を構成する鋼の組成が決まれば、被処理物の硬度、被処理物を構成する鋼の残留オーステナイト量およびミクロ組織などの熱処理品質は、加熱温度および時間により決定される。そのため、熱処理を行なう作業者が、所望の熱処理品質を被処理物に付与するために必要な、およその加熱時間および温度の条件を仮の熱処理条件として決定することは、比較的容易である。   Here, if the composition of the steel constituting the workpiece is determined, the heat treatment quality such as the hardness of the workpiece, the amount of retained austenite of the steel constituting the workpiece and the microstructure is determined by the heating temperature and time. . 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.

さらに、本発明の高周波焼入方法では、冷却タイミング調節工程において、高温部における温度履歴が、予め求められた所望の残留オーステナイト量の上限値以下の残留オーステナイト量が得られる温度履歴の条件を満たし、低温部における温度履歴が、予め求められた所望の硬度の下限値以上の硬度が得られる温度履歴の条件を満たすように加熱時間が調節されて、冷却開始信号が出力される。   Furthermore, in the induction hardening method of the present invention, in the cooling timing adjustment step, the temperature history in the high temperature portion satisfies the condition of the temperature history for obtaining the retained austenite amount equal to or less than the upper limit value of the desired retained austenite amount obtained in advance. The heating time is adjusted so that the temperature history in the low temperature part satisfies the condition of the temperature history at which a hardness equal to or higher than a predetermined lower limit value of the desired hardness is obtained, and a cooling start signal is output.

高周波加熱においては、被処理物は全体が完全に均一に加熱されるのではなく、誘導コイルに近く、磁束の侵入量が多い部位では温度が高く、逆に誘導コイルから遠く、磁束の侵入量が少ない部位では温度が低くなる。ここで、被処理物の用途を考慮すると、被処理物に求められる強度や剛性を確保するために必要な硬度の下限値が決定される。一方、同様に被処理物の用途を考慮すると、被処理物に求められる寸法安定性（形状の経時的変化の小ささ）を確保するために必要な残留オーステナイト量の上限値が決定される。   In high-frequency heating, the workpiece is not heated completely and uniformly, but is close to the induction coil and has a high temperature at the part where the magnetic flux penetrates a lot, and conversely, it is far from the induction coil and the magnetic flux penetrates. The temperature is low at the part where there is little. Here, considering the use of the object to be processed, the lower limit value of the hardness necessary for ensuring the strength and rigidity required for the object to be processed is determined. On the other hand, considering the use of the object to be processed, the upper limit value of the amount of retained austenite necessary for ensuring the dimensional stability (small change in shape with time) required for the object to be processed is determined.

被処理物の硬度は、焼入の際に鋼の素地中に固溶している炭素量に影響を受けるため、基本的には焼入における冷却前の加熱温度が高く加熱時間が長いほど炭素の固溶量が大きくなり、硬度は高くなる。一方、残留オーステナイト量も焼入の際に鋼の素地中に固溶している炭素量に影響を受け、焼入における冷却前の加熱温度が高く加熱時間が長いほど炭素の固溶量が大きくなり、ＭＳ点の温度が低下するため、残留オーステナイト量が多くなる。そのため、磁束の侵入量が少なく温度の低い部位（低温部）が、下限値以上の硬度を得るために必要な温度および時間以上に加熱されており、かつ磁束の侵入量が多く温度の高い部位（高温部）が、上限値以下の残留オーステナイト量を得るために必要な温度および時間以下に加熱されて焼入が実施されることにより、高温部と低温部との間の温度に加熱された部位においては、硬度の下限値および残留オーステナイト量の上限値の双方の条件が満たされる。 Since the hardness of the workpiece is affected by the amount of carbon dissolved in the steel substrate during quenching, the higher the heating temperature before cooling in quenching is, the longer the heating time is. The solid solution amount increases and the hardness increases. On the other hand, the amount of retained austenite is also affected by the amount of carbon dissolved in the steel substrate during quenching, and the higher the heating temperature before cooling in quenching and the longer the heating time, the greater the amount of carbon dissolved. Thus, the amount of retained austenite increases because the temperature at the MS point decreases. Therefore, the part where the amount of magnetic flux intrusion is low and the temperature is low (low temperature part) is heated at the temperature and time required for obtaining the hardness above the lower limit value, and the part where the magnetic flux penetration amount is large and the temperature is high. (High-temperature part) was 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 amount of retained austenite below the upper limit and being quenched. In the region, both the lower limit value of the hardness and the upper limit value of the retained austenite amount are satisfied.

したがって、本発明の高周波焼入方法によれば、上記仮の条件で熱処理が開始された後、詳細な熱処理条件は、所望の硬度および残留オーステナイト量の条件に基づいて決定されて焼入が実施されるため、所望の硬度および残留オーステナイト量を容易に被処理物に付与することができる。なお、被処理物における広い範囲に所望の硬度および残留オーステナイト量を付与するためには、上記の高温部および低温部は、磁束の侵入が最も多い部位および最も少ない部位であることが好ましく、さらに被処理物と誘導コイルとの距離だけでなく、被処理物の形状をも考慮して最も温度の高い部位および最も温度の低い部位であることがより好ましい。なお、被処理物の形状において、たとえば突起部や角部は温度の上昇が大きくなる。   Therefore, according to the induction hardening method of the present invention, after the heat treatment is started under the provisional conditions, the detailed heat treatment conditions are determined based on the conditions of the desired hardness and the amount of retained austenite, and the quenching is performed. Therefore, the desired hardness and the amount of retained austenite can be easily imparted to the workpiece. In order to impart desired hardness and retained austenite amount to a wide range in the object to be processed, it is preferable that the high temperature part and the low temperature part are a part where the penetration of the magnetic flux is the most and a part where the penetration of the magnetic flux is the smallest. In consideration of not only the distance between the object to be processed and the induction coil but also the shape of the object to be processed, it is more preferable that the region has the highest temperature and the lowest temperature. In the shape of the object to be processed, for example, the temperature rises at the protrusions and corners.

以上のように、本発明の高周波焼入方法によれば、温度制御を可能にし、熱処理の条件出しを容易に行なうことを可能にすることにより、過去の生産実績の蓄積が少ない場合や、経験の浅い作業者が熱処理の作業を行なう場合でも、容易にかつ効率よく実施することができるとともに、被処理物の広い範囲に所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することが可能な高周波焼入方法を提供することができる。   As described above, according to the induction hardening method of the present invention, it is possible to control the temperature and easily determine the conditions for the heat treatment. Even when a shallow operator performs heat treatment work, it can be carried out easily and efficiently, and can impart heat treatment quality such as desired hardness and residual austenite amount to a wide range of workpieces. A possible induction hardening method can be provided.

本発明に従った高周波焼入設備は、高周波加熱により被処理物の全体を加熱して焼入硬化する上記の高周波焼入方法に使用される高周波焼入設備であって、被処理物の温度を調節するための温度制御装置と、加熱された前記被処理物が冷却されるべきタイミングを調節するための焼入制御装置とを備えている。   The induction hardening equipment according to the present invention is an induction hardening equipment used in the above induction hardening method for heating and hardening the whole object to be processed by induction heating, and the temperature of the object to be processed. And a quench control device for adjusting the timing at which the heated workpiece is to be cooled.

温度制御装置は、被処理物の温度データを取得し、被処理物の温度データに基づく温度の情報を出力する温度制御用測温装置と、温度制御用測温装置に接続され、温度制御用測温装置からの温度の情報に基づき被処理物の加熱状態を制御するための温度制御信号を出力する温度調節装置と、温度調節装置に接続され、温度調節装置からの温度制御信号に基づき、高周波加熱により被処理物を加熱する加熱装置とを含んでいる。   The temperature control device is connected to a temperature control device for temperature control 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 device for temperature control. A temperature control device that outputs a temperature control signal for controlling the heating state of the object to be processed based on temperature information from the temperature measuring device, and connected to the temperature control device, based on the temperature control signal from the temperature control device, And a heating device for heating the object to be processed by high frequency heating.

焼入制御装置は、被処理物の高温部および低温部の温度データを取得し、被処理物の温度データに基づく温度の情報を出力する焼入用測温装置と、焼入用測温装置に接続され、焼入用測温装置からの温度の情報に基づき加熱時間を調節し、被処理物が冷却されるべきタイミングを決定して冷却開始信号を出力する冷却タイミング調節装置と、冷却タイミング調節装置に接続され、冷却開始信号に基づいて、被処理物を冷却することにより被処理物を焼入硬化する冷却装置とを含んでいる。   A quenching control device acquires temperature data of a high temperature portion and a low temperature portion of an 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 quenching A cooling timing adjusting device that is connected to the temperature measuring device, adjusts the heating time based on temperature information from the quenching temperature measuring device, determines the timing at which the workpiece should be cooled, and outputs a cooling start signal; and cooling timing And a cooling device connected to the adjusting device and quenching and hardening the workpiece by cooling the workpiece based on the cooling start signal.

上述の本発明の高周波焼入方法により被処理物を熱処理することが可能な本発明の高周波焼入設備によれば、温度制御を可能にし、熱処理の条件出しを容易に行なうことを可能にすることにより、過去の生産実績の蓄積が少ない場合や、経験の浅い作業者が熱処理の作業を行なう場合でも、容易にかつ効率よく焼入を実施することができるとともに、被処理物の広い範囲に、所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することが可能な高周波焼入設備を提供することができる。   According to the induction hardening equipment of the present invention capable of heat-treating an object to be processed by the above-described induction hardening method of the present invention, it is possible to control the temperature and easily determine the conditions for the heat treatment. As a result, quenching can be carried out easily and efficiently even when there is little accumulation of past production results, or when inexperienced workers perform heat treatment work, and in a wide range of workpieces. In addition, it is possible to provide an induction hardening equipment capable of imparting heat treatment quality such as desired hardness and residual austenite amount.

本発明に従った高周波焼入品は、上述の高周波焼入方法で熱処理されて作製されたことを特徴とする。本発明の高周波焼入品によれば、温度制御を可能で、熱処理の条件出しを容易に行なうことが可能であることにより、容易にかつ効率よく焼入が実施されているとともに、被処理物の広い範囲に所望の熱処理品質を付与することが可能な本発明の高周波焼入方法により焼入が実施されているため、製造コストが抑制されているとともに、品質の安定した高周波焼入品を提供することができる。   The induction-hardened product according to the present invention is characterized by being heat-treated by the above-described induction hardening method. According to the induction-hardened product of the present invention, the temperature can be controlled and the conditions for the heat treatment can be easily determined, so that 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 a desired heat treatment quality over a wide range of the above, the production cost is suppressed, and the induction-hardened product with stable quality can be obtained. Can be provided.

なお、本発明の高周波焼入品は、たとえば、転がり軸受の軌道輪、転動体などの鋼からなる機械部品に適用することができる。   The induction-hardened product of the present invention can be applied to, for example, mechanical parts made of steel such as a bearing ring of a rolling bearing and a rolling element.

以上の説明から明らかなように、本発明の高周波焼入方法および高周波焼入設備によれば、温度制御を可能にし、熱処理の条件出しを容易に行なうことを可能にすることにより、過去の生産実績の蓄積が少ない場合や、経験の浅い作業者が熱処理の作業を行なう場合でも、容易にかつ効率よく実施することができるとともに、被処理物の広い範囲に所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することが可能な高周波焼入方法、および当該高周波焼入方法を実施するための高周波焼入設備を提供することができる。また、本発明の高周波焼入品によれば、製造コストが抑制され、品質の安定した高周波焼入品を提供することができる。   As is clear from the above description, according to the induction hardening method and induction hardening equipment of the present invention, it is possible to control the temperature and control the past production by making it possible to easily determine the conditions for the heat treatment. Even if there is little accumulation of results or when an inexperienced worker performs heat treatment work, it can be carried out easily and efficiently, and the desired hardness and amount of retained austenite can be applied to a wide range of workpieces. It is possible to provide an induction hardening method capable of imparting a heat treatment quality such as, and an induction hardening equipment 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.

以下、図面に基づいて本発明の実施の形態を説明する。なお、以下の図面において同一または相当する部分には同一の参照番号を付しその説明は繰返さない。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

図１は、本発明の一実施の形態における高周波焼入設備により熱処理されて作製される、高周波焼入品としての転がり軸受外輪の構成を示す概略断面図である。図１を参照して、本実施の形態における転がり軸受外輪の構成を説明する。   FIG. 1 is a schematic cross-sectional view showing the configuration of a rolling bearing outer ring as an induction hardened product that is manufactured by heat treatment using an induction hardening facility according to an embodiment of the present invention. With reference to FIG. 1, the structure of the rolling bearing outer ring | wheel in this Embodiment is demonstrated.

図１を参照して、本実施の形態における高周波焼入品としての転がり軸受外輪１は、円環状の形状を有している。そして、転がり軸受外輪１は、内周面１Ｂに転動体としての玉、ころなどが接触しつつ転走するための転走面１Ｃが形成されているとともに、他の部材と接触して転がり軸受外輪を当該他の部材に対して保持する外周面１Ａを有している。ここで、転がり軸受外輪１は転動疲労寿命および剛性の観点から、５８ＨＲＣ以上の硬度を有していることが好ましい。また、寸法安定性の観点から、残留オーステナイト量は１２体積％以下に抑制されていることが好ましい。   Referring to FIG. 1, a 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 and the like as rolling elements are in contact with the inner peripheral surface 1B, and in contact with other members, the rolling bearing. It has 1 A of outer peripheral surfaces which hold | maintain an outer ring | wheel with respect to the said other member. Here, the rolling bearing outer ring 1 preferably has a hardness of 58 HRC 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.

そして、転がり軸受外輪１は、以下に説明する本発明の一実施の形態における高周波焼入設備を用い、本発明の一実施の形態における高周波焼入方法で熱処理されて作製されているため、製造コストが抑制され、かつ品質の安定した高周波焼入品となっている。   The rolling bearing outer ring 1 is manufactured by using the induction hardening equipment in one embodiment of the present invention described below and heat-treated by the induction hardening method in one embodiment of the present invention. It is an induction-hardened product with reduced cost and stable quality.

次に、本発明の一実施の形態における高周波焼入設備について説明する。図２は、本発明の一実施の形態における高周波焼入設備の構成を示す概略図である。図２を参照して、本発明の一実施の形態における高周波焼入設備の構成を説明する。   Next, the induction hardening equipment in one embodiment of the present invention will be described. FIG. 2 is a schematic diagram showing the configuration of the induction hardening equipment in one embodiment of the present invention. With reference to FIG. 2, the structure of the induction hardening equipment in one embodiment of this invention is demonstrated.

図２を参照して、本実施の形態における高周波焼入設備９０は、高周波加熱により被処理物としての転がり軸受外輪１の全体を加熱して焼入硬化する高周波焼入方法に使用される高周波焼入設備であって、転がり軸受外輪１の温度を調節するための温度制御装置５０と、加熱された転がり軸受外輪１が冷却されるべきタイミングを調節するための焼入制御装置６０とを備えている。   Referring to FIG. 2, induction hardening equipment 90 in the present embodiment is a high frequency used in an induction hardening method in which the entire rolling bearing outer ring 1 as a workpiece is heated and hardened by induction heating. It is a quenching equipment, and includes a temperature control device 50 for adjusting the temperature of the rolling bearing outer ring 1 and a quenching control device 60 for adjusting the timing at which the heated rolling bearing outer ring 1 should be cooled. ing.

温度制御装置５０は、転がり軸受外輪１の温度データを取得し、転がり軸受外輪１の温度データに基づく温度の情報を出力する温度制御用測温装置としての第１放射温度計３と、第１放射温度計３に接続され、第１放射温度計３からの温度の情報に基づき転がり軸受外輪１の加熱状態を制御するための温度制御信号を出力する温度調節装置４と、温度調節装置４に接続され、温度調節装置４からの温度制御信号に基づき、高周波加熱により転がり軸受外輪１を加熱する加熱装置２とを含んでいる。   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. A temperature controller 4 connected to the 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, and the temperature controller 4 And a heating device 2 that heats the rolling bearing outer ring 1 by high-frequency heating based on a temperature control signal from the temperature control device 4.

焼入制御装置６０は、転がり軸受外輪１の高温部である外周面１Ａ（誘導コイルに対向する面）および低温部である外周面１Ｂ（誘導コイルに対向する面の裏側）のそれぞれの温度データを取得し、転がり軸受外輪１の温度データに基づく温度の情報を出力する焼入用測温装置としての第１放射温度計３および第２放射温度計５と、第１放射温度計３および第２放射温度計５に接続され、第１放射温度計３および第２放射温度計５からの温度の情報に基づき加熱時間を調節し、転がり軸受外輪１が冷却されるべきタイミングを決定して冷却開始信号を出力する冷却タイミング調節装置６と、冷却タイミング調節装置６に接続され、冷却開始信号に基づいて、転がり軸受外輪１を冷却することにより転がり軸受外輪１を焼入硬化する冷却装置７とを含んでいる。冷却装置７は、たとえば冷却液を転がり軸受外輪１に噴射することにより冷却する、焼入液噴出装置である。   The quenching control device 60 has respective temperature data of the outer peripheral surface 1A (surface facing the induction coil) which is a high temperature portion of the rolling bearing outer ring 1 and the outer peripheral surface 1B (back side of the surface facing the induction coil) which is a low temperature portion. The first radiation thermometer 3 and the second radiation thermometer 5, the first radiation thermometer 3 and the first radiation thermometer as temperature measuring devices for quenching that output temperature information based on the temperature data of the rolling bearing outer ring 1. 2 It is connected to the radiation thermometer 5, adjusts the heating time based on the temperature information from the first radiation thermometer 3 and the second radiation thermometer 5, determines the timing when the rolling bearing outer ring 1 should be cooled, and cools it A cooling timing adjusting device 6 that outputs a start signal, and a cooling device 7 that is connected to the cooling timing adjusting device 6 and quenches and hardens the rolling bearing outer ring 1 by cooling the rolling bearing outer ring 1 based on the cooling start signal. It contains. The cooling device 7 is a quenching liquid jetting device that cools, for example, by injecting a cooling liquid onto the rolling bearing outer ring 1.

ここで、第１放射温度計３は、温度制御用測温装置と焼入制御用測温装置とを兼ねて設置されている。また、温度調節装置４および冷却タイミング調節装置６は、たとえばそれぞれパーソナルコンピュータであり、１台のパーソナルコンピュータで温度調節装置４と冷却タイミング調節装置６とを兼ねる構成であってもよい。   Here, the first radiation thermometer 3 is installed as both a temperature measuring device for temperature control and a temperature measuring device for quenching control. In addition, 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.

なお、温度制御用測温装置および焼入用測温装置に用いる測温装置の種類は、上述のように放射温度計でもよいが、装置のレイアウト上可能であるならば熱電対などの接触式温度計でもよい。   The type of the temperature measuring device used for the temperature control 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 contact type such as a thermocouple. A thermometer may be used.

次に、上述の高周波焼入設備を用いた本発明の一実施の形態における高周波焼入方法について説明する。図３は、本発明の一実施の形態における高周波焼入方法の概略を示す図である。   Next, an induction hardening method according to an embodiment of the present invention using the above-described induction hardening equipment will be described. FIG. 3 is a diagram showing an outline of the induction hardening method according to one embodiment of the present invention.

図２および図３を参照して、本実施の形態における高周波焼入方法１０は、高周波加熱により被処理物（転がり軸受外輪１）の全体を加熱して焼入硬化する高周波焼入方法であって、転がり軸受外輪１の温度が温度制御装置５０により調節される温度制御工程２０と、焼入制御装置６０により、加熱された転がり軸受外輪１が冷却されるべきタイミングが決定されて、転がり軸受外輪１が冷却される焼入制御工程３０とを備えている。   Referring to FIGS. 2 and 3, induction hardening method 10 in the present embodiment is an induction hardening method in which the entire workpiece (rolling bearing outer ring 1) is heated and hardened by induction heating. Thus, 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, and the rolling bearing. And a quenching control step 30 in which the outer ring 1 is cooled.

温度制御工程２０は、転がり軸受外輪１の温度が、第１放射温度計３により測定される温度制御用測温工程２３と、温度調節装置４により、温度制御用測温工程２３において測定された温度の情報に基づき、転がり軸受外輪１の加熱状態を制御するための温度制御信号が出力される温度調節工程２４と、加熱装置２を用いて、温度制御信号に基づいて、高周波加熱により転がり軸受外輪１が加熱される加熱工程２２とを含んでいる。   In the temperature control process 20, the temperature of the rolling bearing outer ring 1 was measured in the temperature control process 23 for measuring temperature by the first radiation thermometer 3 and in the temperature measurement process 23 for controlling temperature by the temperature controller 4. Based on the temperature information, a temperature control step 24 in which a temperature control signal for controlling the heating state of the rolling bearing outer ring 1 is output, and a rolling bearing by high-frequency heating based on the temperature control signal using the heating device 2. Heating step 22 in which the outer ring 1 is heated.

焼入制御工程３０は、焼入用測温工程３５と、冷却タイミング調節工程３６と、冷却工程３７とを含んでいる。焼入用測温工程３５においては、転がり軸受外輪１において、高周波加熱による温度の上昇が転がり軸受外輪１において最も大きい表面の部位である高温部としての外周面１Ａと、高周波加熱による温度の上昇が転がり軸受外輪１において最も小さい表面の部位である低温部としての内周面１Ｂとの温度が、それぞれ第１放射温度計３と第２放射温度計５とにより測定される。冷却タイミング調節工程３６においては、冷却タイミング調節装置６により、焼入用測温工程３５において測定された温度の情報に基づき加熱時間が調節され、転がり軸受外輪１が冷却されるべきタイミングが決定されて冷却開始信号が出力される。冷却工程３７においては、冷却装置７により、冷却開始信号に基づいて、転がり軸受外輪１がＡ１点以上の温度域からＭＳ点以下の温度域に冷却されることにより、転がり軸受外輪１が焼入硬化される。 The quenching control process 30 includes a quenching temperature measurement process 35, a cooling timing adjustment process 36, and a cooling process 37. In the temperature measurement process 35 for quenching, in the outer ring 1 of the rolling bearing, an increase in temperature due to high frequency heating is performed on the outer peripheral surface 1A as a high temperature portion, which is the largest surface portion in the outer ring 1 of the rolling bearing, and a temperature increase due to high frequency heating. Are measured by the first radiation thermometer 3 and the second radiation thermometer 5, respectively, as the temperature of the inner peripheral surface 1B as the low temperature portion which is the smallest surface portion in the rolling bearing outer ring 1. In the cooling timing adjustment step 36, 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 the timing at which the rolling bearing outer ring 1 should be cooled. Cooling start signal is output. In the cooling step 37, the rolling bearing outer ring 1 is cooled by the cooling device 7 based on the cooling start signal from the temperature range of A 1 point or higher to the temperature range of M S point or lower. Quench and harden.

そして、冷却タイミング調節工程３６においては、外周面１Ａにおける温度および加熱時間を含む温度履歴が、予め求められた所望の残留オーステナイト量の上限値以下の残留オーステナイト量が得られる温度履歴（加熱開始後の各時間における温度の実績）の条件を満たし、内周面１Ｂにおける温度および加熱時間を含む温度履歴が、予め求められた所望の硬度の下限値以上の硬度が得られる温度履歴の条件を満たすように加熱時間が調節されて、冷却開始信号が出力される。具体的には、加熱時間の調節は、予め求められた所望の硬度を得るための加熱時間と加熱温度との関係を示す条件式、および所望の残留オーステナイト量を得るための加熱時間と加熱温度との関係を示す条件式に基づいて、実施される。   In the cooling timing adjustment step 36, the temperature history including the temperature and the heating time on the outer peripheral surface 1A is a temperature history (after heating is started) in which a retained austenite amount equal to or less than a predetermined upper limit value of the retained austenite amount is obtained. The temperature history including the temperature and heating time on the inner peripheral surface 1B satisfies the condition of the temperature history for obtaining a hardness equal to or higher than the lower limit value of the desired hardness obtained in advance. The heating time is adjusted as described above, and a cooling start signal is output. Specifically, the adjustment of the heating time is performed by adjusting the conditional expression indicating the relationship between the heating time and the heating temperature for obtaining the desired hardness obtained in advance, and the heating time and the heating temperature for obtaining the desired amount of retained austenite. It is implemented based on a conditional expression indicating the relationship between

本実施の形態における高周波焼入設備を用いて、本実施の形態における高周波焼入方法を実施することにより、温度制御が可能となり、熱処理の条件出しを容易に行なうことができるため、過去の生産実績の蓄積が少ない場合や、経験の浅い作業者が熱処理の作業を行なう場合でも、容易にかつ効率よく焼入硬化処理を実施することができるとともに、被処理物としての転がり軸受外輪１の広い範囲に所望の硬度や残留オ−ステナイト量などの熱処理品質を付与することができる。   By performing the induction hardening method in the present embodiment using the induction hardening equipment in the present embodiment, temperature control becomes possible and conditions for heat treatment can be easily determined. Even when the accumulation of results is small or when an inexperienced worker performs a heat treatment work, the hardening and hardening process can be easily and efficiently performed, and the rolling bearing outer ring 1 as a workpiece is wide. Heat treatment quality such as desired hardness and residual austenite amount can be imparted to the range.

なお、Ａ１点とは鋼を加熱した場合に、鋼の組織がフェライトからオーステナイトに変態を開始する温度に相当する点をいう。また、ＭＳ点とはオーステナイト化した鋼が冷却される際に、マルテンサイト化を開始する温度に相当する点をいう。 Note that the point A when heated steel refers to a point that the structure of the steel corresponds to the temperature to start the transformation from ferrite to austenite. Further, the M S point when the steel was austenitized is cooled, it refers to a point corresponding to a temperature to initiate the martensite.

次に、本実施の形態における高周波焼入設備９０を用いた本実施の形態における高周波焼入方法１０、特に冷却タイミング調節工程３６の具体的手順について、素材としてＪＩＳ ＳＵＪ２を採用した場合を例に詳細に説明する。   Next, with respect to the specific procedure of the induction hardening method 10 in this embodiment using the induction hardening equipment 90 in this embodiment, particularly the cooling timing adjustment step 36, a case where JIS SUJ2 is adopted as a material is taken as an example. This will be described in detail.

冷却タイミング調節工程３６は、たとえば以下のようにＴＴＡ（Ｔｉｍｅ Ｔｅｍｐｅｒａｔｕｒｅ Ａｕｓｔｉｎｉｔｉｚａｔｉｏｎ）線図を作成し、当該ＴＴＡ線図における条件式に基づいて加熱時間を調節することにより実施することができる。   The cooling timing adjustment step 36 can be performed, for example, by creating a TTA (Time Temperature Authentication) diagram as follows and adjusting the heating time based on the conditional expression in the TTA diagram.

図４は、本実施の形態におけるＴＴＡ線図の作製方法を説明するための図である。図４において、横軸は加熱開始からの経過時間、縦軸は温度を示している。図４を参照して、ＴＴＡ線図の作製方法を説明する。   FIG. 4 is a diagram for explaining a method for producing a TTA diagram in this embodiment. In FIG. 4, the horizontal axis represents the elapsed time from the start of heating, and the vertical axis represents the temperature. With reference to FIG. 4, a method for producing a TTA diagram will be described.

図４を参照して、たとえば、均一な加熱および冷却が可能なＳＵＪ２製の小型の試験片（６２０６型番玉軸受外輪、外径φ６２ｍｍ、内径φ５２ｍｍ、厚みｔ１６ｍｍのリング状）に対して、種々の昇温速度で加熱し、種々の時間経過後に急冷することにより、焼入を実施し、さらに、１８０℃で１２０分間保持することにより、当該試験片に焼戻を実施する。そして、各試験片の残留オーステナイト量および硬度を測定する。試験片の硬度は、たとえば熱処理後の被処理物の一部を研磨し、当該研磨面の硬度をロックウェル硬度計、ビッカース硬度計などの硬度計により測定して得ることができる。また、残留オーステナイト量は、たとえば熱処理後の試験片を電解研磨し、Ｘ線回折計（ＸＲＤ）を用いて、当該研磨面のマルテンサイトα（２１１）面とオーステナイトγ（２２０）面との回折強度とを測定することにより、算出することができる。   Referring to FIG. 4, for example, for a small test piece made of SUJ2 capable of uniform heating and cooling (6206 model ball bearing outer ring, outer diameter φ62 mm, inner diameter φ52 mm, thickness t16 mm ring shape) Quenching is performed by heating at a rate of temperature rise and rapidly cooling after a lapse of various times. Further, the specimen is tempered 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 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 is, for example, diffracted between the martensite α (211) surface and the austenite γ (220) surface of the polished surface using an X-ray diffractometer (XRD) after electrolytically polishing the test piece after the heat treatment. It can be calculated by measuring the intensity.

図４には、昇温速度約３１１℃／秒（一点鎖線）、約６５℃／秒（破線）および約２０℃／秒（実線）の場合の試験片の加熱履歴が示されている。そして、昇温速度３１１℃／秒の場合、硬度が５８ＨＲＣとなった点がα１、残留オーステナイト量が１２体積％となった点がα２で示されている。同様に、約６５℃／秒の場合の硬度が５８ＨＲＣとなった点、および残留オーステナイト量が１２体積％となった点がそれぞれβ１およびβ２、約２０℃／秒の場合の硬度が５８ＨＲＣとなった点、および残留オーステナイト量が１２体積％となった点がそれぞれγ１およびγ２として、記載されている。このような実験を種々の昇温速度で実施し、５８ＨＲＣとなった点、および残留オーステナイト量が１２体積％となった点を、それぞれたとえば指数関数でフィッティングして硬度：５８ＨＲＣを示す曲線、および残留オーステナイト量１２体積％を示す曲線を算出する。そして、当該曲線を作図することにより、ＴＴＡ線図が完成する。このＴＴＡ線図は、形状に関係なく素材により決定されるため、被処理物の形状が変更されても、素材が同種である限り、使用することができる。 FIG. 4 shows the heating history of the test piece when the heating rate is about 311 ° C./second (dashed line), about 65 ° C./second (dashed line), and about 20 ° C./second (solid line). When the heating rate is 311 ° C./sec, the point at which the hardness is 58 HRC is indicated by α 1 , and the point at which the residual austenite amount is 12% by volume is indicated by α 2 . Similarly, β 1 and β 2 have a hardness of 58 HRC at about 65 ° C./second and 12 vol% retained austenite, and 58 HRC at a temperature of about 20 ° C./second. And the point at which the amount of retained austenite is 12% by volume are described as γ 1 and γ 2, respectively. Such an experiment was performed at various heating rates, and the point at which 58 HRC was obtained and the point at which the amount of retained austenite was 12% by volume were fitted with, for example, an exponential function, respectively, and a curve showing hardness: 58 HRC, and A curve indicating a residual austenite amount of 12% by volume is calculated. Then, the TTA diagram is completed by drawing the curve. Since this TTA diagram is determined by the material regardless of the shape, it can be used as long as the material is the same even if the shape of the workpiece is changed.

次に、当該ＴＴＡ線図を用いた冷却タイミング調節工程３６の実施方法について説明する。図５は、ＴＴＡ線図を用いた冷却タイミング調節工程の実施方法を説明するための図である。図５において、横軸は加熱開始からの経過時間、縦軸は温度を示している。また、図５には、高周波加熱中の転がり軸受外輪１の高温部（外周面１Ａ）および低温部（内周面１Ｂ）の測温結果が合わせて示されている。   Next, a method for performing the cooling timing adjustment step 36 using the TTA diagram will be described. FIG. 5 is a diagram for explaining a method of performing the cooling timing adjustment step using the TTA diagram. In FIG. 5, the horizontal axis represents 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.

図５を参照して、硬度：５８ＨＲＣの曲線は、当該曲線よりも高温側では５８ＨＲＣ以上の硬度となっていることを示しており、算出された曲線の式は
温度ＴＨ＝０．０２ｅｘｐ（９．２８２３ｔ−０．０５）＋７９０・・・（１）
である。また、残留オーステナイト量：１２体積％の曲線は、当該曲線よりも低温側では１２体積％以下の残留オーステナイト量となっていることを示しており、算出された曲線の式は
温度Ｔγ＝８．０６×１０−１８ｅｘｐ（４５ｔ−０．０１）＋８６０・・・（２）
である。 Referring to Figure 5, hardness: curve of 58HRC, in the high temperature side of the curve indicates that it is the hardness of at least 58HRC, the formula of the calculated curve temperature T H = 0.02exp ( 9.2823t− 0.05 ) +790 (1)
It is. Moreover, the curve of residual austenite amount: 12 volume% has shown that it is the amount of residual austenite of 12 volume% or less in the low temperature side rather than the said curve, and the formula of the calculated curve is temperature Tγ = 8. .06 × 10 −18 exp (45t −0.01 ) +860 (2)
It is.

冷却タイミング調節工程３６においては、加熱が開始されると各時間においてリアルタイムに高温部（外周面１Ａ）の温度が式（２）のＴγと比較され、高温部の温度がＴγよりも低いことが確認される。一方、同時に低温部（内周面１Ｂ）の温度が式（１）のＴＨと比較され、ＴＨよりも大きくなった時間帯に冷却開始信号が出力され、被処理物（転がり軸受外輪１）が冷却されることにより、焼入硬化される。 In the cooling timing adjustment step 36, when heating is started, the temperature of the high temperature portion (outer peripheral surface 1A) is compared with T γ in the formula (2) in real time at each time, and the temperature of the high temperature portion is lower than T γ. That is confirmed. On the other hand, are compared the temperature of the low temperature portion (the inner peripheral surface 1B) is a T H of the formula (1) at the same time, cooling start signal to the time zone is larger than T H is outputted, the processing object (the rolling bearing outer ring 1 ) Is cooled and hardened.

すなわち、図５を参照して、時間ｔ１においては、低温部（内周面１Ｂ）の温度が硬度：５８ＨＲＣの曲線よりも低温側にあるため、加熱が不足している。また、時間ｔ３においては、高温部（外周面１Ａ）の温度が残留オーステナイト量：１２体積％の曲線よりも高温側となっているため、加熱が過剰となっている。一方、時間ｔ２においては、低温部（内周面１Ｂ）の温度が硬度：５８ＨＲＣの曲線よりも高温側にあり、かつ高温部（外周面１Ａ）の温度が残留オーステナイト量：１２体積％の曲線よりも低温側となっているため、この時点で冷却開始信号を出力し、冷却を開始することで、被処理物全体が硬度５８ＨＲＣかつ残留オーステナイト量１２体積％以下の条件を満たす焼入を実施することができる。 That is, referring to FIG. 5, at time t 1 , the temperature of the low temperature portion (inner peripheral surface 1B) is on the low temperature side of the curve of hardness: 58HRC, and thus heating is insufficient. Further, at time t 3, the temperature is the amount of retained austenite high temperature portion (the outer peripheral surface 1A): 12 for that is the high temperature side than the volume percent of the curve, the heating is excessive. On the other hand, at time t 2, the temperature of the low temperature portion (the inner peripheral surface 1B) hardness: the curve of 58HRC is in the high temperature side, and the temperature is the amount of retained austenite high temperature portion (the outer peripheral surface 1A): 12% by volume Since it is on the lower temperature side than the curve, a cooling start signal is output at this point, and by starting the cooling, quenching is performed so that the entire workpiece satisfies the condition that the hardness is 58 HRC and the amount of retained austenite is 12 volume% or less. Can be implemented.

以下、本発明の実施例について説明する。本発明の高周波焼入設備を用い、本発明の高周波焼入方法による高周波焼入を実施し、その有効性を確認する試験を行なった。試験の手順は以下のとおりである。   Examples of the present invention will be described below. Using the induction hardening equipment of the present invention, induction hardening was performed by the induction hardening method of the present invention, and a test for confirming the effectiveness was conducted. The test procedure is as follows.

転がり軸受の軌道輪を想定したＳＵＪ２製のリング状試験片（外径φ６２ｍｍ×内径φ５２ｍｍ×幅ｔ１６ｍｍのリング状試験片）を準備し、図２に基づいて説明した上記実施の形態の高周波焼入設備を用い、図３に基づいて説明した上記実施の形態の高周波焼入方法により焼入を実施した。焼入の条件としては、温度制御工程における保持温度を９００℃、９５０℃、１０００℃の３水準とし、昇温速度は２１０℃／秒で一定とする条件を採用した。そして、焼入後、１８０℃で１２０分間保持することにより焼戻を行なった。その後、試験片の外周面（高温部）および内周面（低温部）の硬度および残留オーステナイト量を測定した。なお、硬度および残留オーステナイト量の目標値はそれぞれ５８ＨＲＣ（６５３ＨＶ）以上、１２体積％以下とした。表１に試験の結果を示す。   A ring-shaped test piece (outer diameter φ62 mm × inner diameter φ52 mm × width t16 mm ring-shaped test piece) made of SUJ2 assuming a rolling bearing raceway is prepared, and induction hardening according to the embodiment described above with reference to FIG. Using equipment, quenching was performed by the induction hardening method of the above-described embodiment described with reference to FIG. As the quenching conditions, the holding temperature in the temperature control step was set at three levels of 900 ° C., 950 ° C., and 1000 ° C., and the temperature rising rate was constant at 210 ° C./second. And after tempering, it tempered by hold | maintaining for 120 minutes at 180 degreeC. Thereafter, the hardness and the amount of retained austenite of the outer peripheral surface (high temperature portion) and the inner peripheral surface (low temperature portion) of the test piece were measured. The target values of hardness and retained austenite amount were set to 58 HRC (653 HV) or more and 12% by volume or less, respectively. Table 1 shows the test results.

Figure 2007239039
Figure 2007239039

表１を参照して、温度制御工程の保持温度の条件にかかわらず、測定された硬度および残留オーステナイト量はいずれも目標値をクリアしていた。このことから、本発明の高周波焼入方法および高周波焼入設備によれば、１０００℃という高温での焼入処理が可能であるため、焼入の際の加熱時間の短縮を可能とし、焼入硬化処理の効率化に寄与しうることが確認された。   Referring to Table 1, regardless of the holding temperature condition of the temperature control step, the measured hardness and the retained austenite amount both cleared the target values. From this, according to the induction hardening method and induction hardening equipment of the present invention, it is possible to perform a quenching process at a high temperature of 1000 ° C., and therefore it is possible to shorten the heating time at the time of quenching, It was confirmed that it can contribute to the efficiency of the curing process.

今回開示された実施の形態および実施例はすべての点で例示であって、制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味、および範囲内でのすべての変更が含まれることが意図される。   The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

本発明の高周波焼入方法および高周波焼入設備は、高周波加熱により被処理物を加熱して焼入を行なう高周波焼入方法および高周波焼入設備に特に有利に適用され得る。また、本発明の高周波焼入品は、高周波加熱により加熱されて焼入硬化される高周波焼入品に特に有利に適用され得る。   The induction hardening method and induction hardening equipment of the present invention can be applied particularly advantageously to an induction hardening method and induction hardening equipment in which an object to be processed is quenched by induction heating. The induction-hardened product of the present invention can be particularly advantageously applied to an induction-hardened product that is heated and hardened by induction heating.

本発明の一実施の形態における高周波焼入設備により熱処理されて作製される、高周波焼入品としての転がり軸受外輪の構成を示す概略断面図である。It is a schematic sectional drawing which shows the structure of the rolling bearing outer ring | wheel as induction hardening goods produced by heat-processing with the induction hardening equipment in one embodiment of this invention. 本発明の一実施の形態における高周波焼入設備の構成を示す概略図である。It is the schematic which shows the structure of the induction hardening equipment in one embodiment of this invention. 本発明の一実施の形態における高周波焼入方法の概略を示す図である。It is a figure which shows the outline of the induction hardening method in one embodiment of this invention. ＴＴＡ線図の作製方法を説明するための図である。It is a figure for demonstrating the preparation methods of a TTA diagram. ＴＴＡ線図を用いた冷却タイミング調節工程の実施方法を説明するための図である。It is a figure for demonstrating the implementation method of the cooling timing adjustment process using a TTA diagram.

符号の説明Explanation of symbols

１ 転がり軸受外輪、１Ａ 外周面、１Ｂ 内周面、１Ｃ 転走面、２ 加熱装置、３ 第１放射温度計、４ 温度調節装置、５ 第２放射温度計、６ 冷却タイミング調節装置、７ 冷却装置、１０ 高周波焼入方法、２０ 温度制御工程、２２ 加熱工程、２３ 温度制御用測温工程、２４ 温度調節工程、３０ 焼入制御工程、３５ 焼入用測温工程、３６ 冷却タイミング調節工程、３７ 冷却工程、５０ 温度制御装置、６０ 焼入制御装置、９０ 高周波焼入設備。   DESCRIPTION OF SYMBOLS 1 Rolling bearing outer ring, 1A outer peripheral surface, 1B inner peripheral surface, 1C rolling surface, 2 Heating device, 3rd radiation thermometer, 4 Temperature control device, 5 2nd radiation thermometer, 6 Cooling timing control device, 7 Cooling Apparatus, 10 induction hardening method, 20 temperature control process, 22 heating process, 23 temperature measurement process for temperature control, 24 temperature adjustment process, 30 quenching control process, 35 temperature measurement process for quenching, 36 cooling timing adjustment process, 37 cooling process, 50 temperature control device, 60 quenching control device, 90 induction hardening equipment.

Claims (3)

高周波加熱により被処理物の全体を加熱して焼入硬化する高周波焼入方法であって、
前記被処理物の温度が調節される温度制御工程と、
加熱された前記被処理物が冷却されるべきタイミングが決定されて、前記被処理物が冷却される焼入制御工程とを備え、
前記温度制御工程は、
前記被処理物の温度が測定される温度制御用測温工程と、
前記温度制御用測温工程において測定された温度の情報に基づき、前記被処理物の加熱状態を制御するための温度制御信号が出力される温度調節工程と、
前記温度制御信号に基づいて、前記高周波加熱により前記被処理物が加熱される加熱工程とを含み、
前記焼入制御工程は、
前記被処理物において、前記高周波加熱による温度の上昇が前記被処理物の内部よりも大きい表面の部位である高温部と、前記高周波加熱による温度の上昇が前記被処理物の内部よりも小さい表面の部位である低温部との温度が測定される焼入用測温工程と、
前記焼入用測温工程において測定された温度の情報に基づき加熱時間が調節され、前記被処理物が冷却されるべきタイミングが決定されて冷却開始信号が出力される冷却タイミング調節工程と、
前記冷却開始信号に基づいて、前記被処理物が冷却されることにより前記被処理物が焼入硬化される冷却工程とを含み、
前記冷却タイミング調節工程においては、
前記高温部における温度および加熱時間を含む温度履歴が、予め求められた所望の残留オーステナイト量の上限値以下の残留オーステナイト量が得られる温度履歴の条件を満たし、
前記低温部における温度および加熱時間を含む温度履歴が、予め求められた所望の硬度の下限値以上の硬度が得られる温度履歴の条件を満たすように前記加熱時間が調節されて、前記冷却開始信号が出力される、高周波焼入方法。 An induction hardening method in which the whole object to be processed is heated and hardened by induction heating,
A temperature control step in which the temperature of the workpiece is adjusted;
A timing at which the heated object to be processed is cooled, and a quenching control step in which the object to be processed is cooled, and
The temperature control step includes
A temperature control temperature measurement step in which the temperature of the object to be processed is measured,
Based on the temperature information measured in the temperature control temperature measurement step, a temperature adjustment step for outputting a temperature control signal for controlling the heating state of the workpiece,
A heating step in which the object to be processed is heated by the high-frequency heating based on the temperature control signal,
The quench control process includes
In the object to be processed, a high temperature portion that is a surface portion where the temperature increase due to the high frequency heating is larger than the inside of the object to be processed, and a surface where the temperature increase due to the high frequency heating is smaller than that inside the object to be processed. A temperature measurement process for quenching in which the temperature of the low temperature part, which is the part of
A cooling timing adjustment step in which a heating time is adjusted based on the temperature information measured in the quenching temperature measurement step, a timing at which the workpiece is to be cooled is determined, and a cooling start signal is output;
A cooling step in which the workpiece is quenched and hardened by cooling the workpiece based on the cooling start signal,
In the cooling timing adjustment step,
The temperature history including the temperature and the heating time in the high temperature part satisfies the condition of the temperature history for obtaining the retained austenite amount below the upper limit of the desired retained austenite amount obtained in advance,
The heating start time is adjusted so that the temperature history including the temperature and the heating time in the low temperature part satisfies the condition of the temperature history at which a hardness equal to or higher than a predetermined lower limit of the desired hardness is obtained, and the cooling start signal Is an induction hardening method. 高周波加熱により被処理物の全体を加熱して焼入硬化する請求項１に記載の高周波焼入方法に使用される高周波焼入設備であって、
前記被処理物の温度を調節するための温度制御装置と、
加熱された前記被処理物が冷却されるべきタイミングを調節するための焼入制御装置とを備え、
前記温度制御装置は、
前記被処理物の温度データを取得し、前記被処理物の温度データに基づく温度の情報を出力する温度制御用測温装置と、
前記温度制御用測温装置に接続され、前記温度制御用測温装置からの温度の情報に基づき前記被処理物の加熱状態を制御するための温度制御信号を出力する温度調節装置と、
前記温度調節装置に接続され、前記温度調節装置からの前記温度制御信号に基づき、高周波加熱により前記被処理物を加熱する加熱装置とを含み、
前記焼入制御装置は、
前記被処理物の前記高温部および前記低温部の温度データを取得し、前記被処理物の温度データに基づく温度の情報を出力する焼入用測温装置と、
前記焼入用測温装置に接続され、前記焼入用測温装置からの温度の情報に基づき加熱時間を調節し、前記被処理物が冷却されるべきタイミングを決定して冷却開始信号を出力する冷却タイミング調節装置と、
前記冷却タイミング調節装置に接続され、前記冷却開始信号に基づいて、前記被処理物を冷却することにより前記被処理物を焼入硬化する冷却装置とを含む、高周波焼入設備。 The induction hardening equipment used in the induction hardening method according to claim 1, wherein the whole object to be processed is heated and hardened by induction heating,
A temperature control device for adjusting the temperature of the workpiece;
A quenching control device for adjusting the timing at which the heated object to be processed is cooled, and
The temperature control device includes:
A temperature measuring device for temperature control that obtains temperature data of the object to be processed and outputs temperature information based on the temperature data of the object to be processed;
A temperature adjusting device connected to the temperature control temperature measuring device and outputting a temperature control signal for controlling a heating state of the object to be processed based on temperature information from the temperature control temperature measuring device;
A heating device connected to the temperature adjustment device, and heating the object to be processed by high frequency heating based on the temperature control signal from the temperature adjustment device,
The quenching control device
A temperature measuring device for quenching that obtains temperature data of the high temperature portion and the low temperature portion of the object to be processed, and outputs temperature information based on the temperature data of the object to be processed;
Connected to the temperature measuring device for quenching, adjusts the heating time based on the temperature information from the temperature measuring device for quenching, determines the timing at which the workpiece should be cooled, and outputs a cooling start signal A cooling timing adjusting device,
Induction hardening equipment including 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. 請求項１に記載の高周波焼入方法で熱処理されて作製されたことを特徴とする、高周波焼入品。   An induction-hardened product produced by heat treatment by the induction hardening method according to claim 1.
JP2006064249A 2006-03-09 2006-03-09 Induction-hardening method, induction-hardening facility and induction-hardened article Withdrawn JP2007239039A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2006064249A JP2007239039A (en) 2006-03-09 2006-03-09 Induction-hardening method, induction-hardening facility and induction-hardened article
PCT/JP2007/053033 WO2007102306A1 (en) 2006-03-09 2007-02-20 Method of high-frequency quenching, high-frequency quenching apparatus, and product of high-frequency quenching

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006064249A JP2007239039A (en) 2006-03-09 2006-03-09 Induction-hardening method, induction-hardening facility and induction-hardened article

Publications (1)

Publication Number Publication Date
JP2007239039A true JP2007239039A (en) 2007-09-20

Family

ID=38584861

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006064249A Withdrawn JP2007239039A (en) 2006-03-09 2006-03-09 Induction-hardening method, induction-hardening facility and induction-hardened article

Country Status (1)

Country Link
JP (1) JP2007239039A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2915886A4 (en) * 2012-10-31 2016-06-29 Ntn Toyo Bearing Co Ltd Heat treatment method and method for manufacturing machine part
CN113390533A (en) * 2021-06-15 2021-09-14 中国兵器工业第五九研究所 Method for detecting surface temperature of workpiece in heat treatment process

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2915886A4 (en) * 2012-10-31 2016-06-29 Ntn Toyo Bearing Co Ltd Heat treatment method and method for manufacturing machine part
US10161015B2 (en) 2012-10-31 2018-12-25 Ntn Corporation Heat treatment method and method of manufacturing machine part
CN113390533A (en) * 2021-06-15 2021-09-14 中国兵器工业第五九研究所 Method for detecting surface temperature of workpiece in heat treatment process

Similar Documents

Publication Publication Date Title
JP2008303402A (en) High frequency induction-hardening apparatus and method for manufacturing rolling bearing, rolling bearing
JP2006265606A (en) High frequency induction heat-treatment method, high frequency induction heat-treatment facility and high frequency induction heat-treating article
JP2009203498A (en) High frequency-induction heating method, heating apparatus and bearing
WO2016208343A1 (en) Method for producing bearing part
JP2009197312A (en) Method for correcting deformation of annular member
JP5622138B2 (en) Heat treatment method for steel workpieces
WO2014069149A1 (en) Heat treatment method and method for manufacturing machine part
JP2006291248A (en) Method and equipment for high frequency induction heat treatment, thin member and thrust bearing
JP6211365B2 (en) Heat treatment method for ring-shaped member
JP2007239039A (en) Induction-hardening method, induction-hardening facility and induction-hardened article
JP2009167484A (en) Heat-treatment apparatus for cylindrical metallic member
CN103443300B (en) Method for processing component such as gear
WO2007102306A1 (en) Method of high-frequency quenching, high-frequency quenching apparatus, and product of high-frequency quenching
JP2007239043A (en) Induction heat-treatment method and induction heat-treated article
JP6191630B2 (en) Workpiece manufacturing method
CN110121565B (en) Bearing component and method for manufacturing same
JP2001020016A (en) Heat treatment method of metallic member
JP2007217759A (en) Induction hardening method, induction hardening facility and induction-hardened product
US20090071954A1 (en) Induction Tempering Method, Induction Tempering Apparatus, and Induction Tempered Product
Yücel et al. Flywheel starter ring gear failures and hardness variation reduction in surface hardening process
Rudnev Recent inventions and innovations in induction hardening of gears and gear-like components
CN106636570A (en) Heat treatment method for repairing of carburization pin bush
JP2005133215A (en) Heat treatment system
CN101048517A (en) High-frequency heat treatment apparatus, high-frequency heat treatment process, and high-frequency heat treated article
JP2007211283A (en) High frequency-induction hardening method, induction hardening facility and induction hardened article

Legal Events

Date Code Title Description
A300 Withdrawal of application because of no request for examination

Free format text: JAPANESE INTERMEDIATE CODE: A300

Effective date: 20090512