JP2009270155A - Nitriding quenching method and nitrided quenched part - Google Patents

Nitriding quenching method and nitrided quenched part Download PDF

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JP2009270155A
JP2009270155A JP2008121592A JP2008121592A JP2009270155A JP 2009270155 A JP2009270155 A JP 2009270155A JP 2008121592 A JP2008121592 A JP 2008121592A JP 2008121592 A JP2008121592 A JP 2008121592A JP 2009270155 A JP2009270155 A JP 2009270155A
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temperature
workpiece
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Izuru Yamamoto
出 山本
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Toyota Motor Corp
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<P>PROBLEM TO BE SOLVED: To provide a nitriding quenching method which can obtain a desired nitrogen penetration depth in a short time instead of the conventional nitriding quenching treatment where, since treatment has been performed at ≥600°C over the whole process of the treatment, nitrogen penetration velocity to the surface of a workpiece is slow, and a long time has been required for obtaining a desired nitrogen penetration depth, and to provide a nitrided quenched part. <P>SOLUTION: Disclosed is a nitriding quenching method where nitrogen is penetratively diffused into a workpiece composed of iron or an iron alloy, and further, quenching is performed. A workpiece is installed in a heat treatment furnace to be fed with an ammonia gas, the temperature in the heat treatment furnace is increased to a temperature Ta in a ferrite region of the workpiece, so as to be held for a prescribed time t1, thereafter, the temperature in the heat treatment furnace is increased to a temperature Tb in an austenite region of the workpiece, so as to be held for a prescribed time t2, and subsequently, the workpiece is rapidly cooled and is quenched. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、鉄または鉄合金にて構成されるワークに窒素を浸透拡散させるとともに焼入れを行う浸窒焼入れ方法および浸窒焼入れ品に関する。   The present invention relates to a nitriding and quenching method and a nitriding and quenching product in which nitrogen is permeated and diffused in a workpiece made of iron or an iron alloy and quenched.

従来から、鉄や鉄合金にて構成されるワークの表面に窒素を浸透拡散させるとともに焼入れ処理を施して、ワークの表面に硬化層を形成した浸窒焼入れ品を得ることが行われている。
このような浸窒焼入れ品を製造する方法としては、例えば特許文献１に示すようなものがある。 Conventionally, a nitrogen-quenched product in which a hardened layer is formed on the surface of a work is obtained by infiltrating and diffusing nitrogen on the surface of a work made of iron or an iron alloy and quenching.
As a method for producing such a nitrocarburized product, for example, there is a method shown in Patent Document 1.

つまり、鉄や鉄合金にて構成されたワークを密閉された炉内に装入し、次いで浸窒処理に悪影響を与えないガスを導入し、かつ該ガスの導入に前後して該炉内を６００〜８００℃の浸窒温度に昇温させ、さらに前記ワークを前記浸窒温度に昇温させた後、該浸窒温度を維持しつつ、前記炉内にアンモニアガスを単独でまたは浸窒処理に悪影響を与えないガスとともに導入して浸窒処理し、前記ワークに表面から窒素を浸透拡散させたうえで、前記炉内から取り出し、急冷して焼入れを行うことにより、浸窒焼入れ品が製造されている。   That is, a work made of iron or an iron alloy is charged into a closed furnace, and then a gas that does not adversely affect the nitriding treatment is introduced, and the inside of the furnace is introduced before and after the introduction of the gas. The temperature is raised to a nitriding temperature of 600 to 800 ° C., and further the temperature of the workpiece is raised to the nitriding temperature. Then, ammonia gas is singly or nitridized in the furnace while maintaining the nitriding temperature. Nitrogen-quenched products are manufactured by introducing nitrogen together with a gas that does not adversely affect the surface of the workpiece, allowing nitrogen to permeate and diffuse into the workpiece from the surface, taking it out of the furnace, quenching and quenching. Has been.

このように、従来においてワークに浸窒焼入れ処理を行うときには、浸窒処理の全工程にわたってワークを６００〜８００℃の温度に維持している。
これはワークに焼入れ処理を行うためには、ワークの組織をオーステナイト（γ）にする必要があるが、ワークがオーステナイトになる温度領域が６００℃以上となっているために、前記温度での浸窒焼入れ処理が行われている。 As described above, when the nitriding and quenching process is conventionally performed on the workpiece, the workpiece is maintained at a temperature of 600 to 800 ° C. throughout the entire nitriding process.
In order to quench the workpiece, it is necessary to change the workpiece structure to austenite (γ). However, since the temperature range in which the workpiece becomes austenite is 600 ° C. or higher, the immersion at the above temperature is required. Nitroque quenching treatment is performed.

しかし、前述のように、浸窒焼入れ処理の全工程にわたって６００℃以上の温度にて処理を行った場合、ワーク表面への窒素の侵入速度が遅く、所望の窒素侵入深さを得ようとすると、長時間を要することとなっていた。
特開２００７−４６０８８号公報 However, as described above, when the treatment is performed at a temperature of 600 ° C. or higher over the entire nitriding and quenching treatment, the penetration rate of nitrogen into the workpiece surface is slow, so that a desired nitrogen penetration depth is obtained. It was supposed to take a long time.
JP 2007-46088 A

そこで、本発明では、ワーク表面への窒素の侵入速度を向上して、短時間で所望の窒素侵入深さを得ることができる、言い換えれば同じ処理時間で窒素侵入深さを向上することができる浸窒焼入れ方法および浸窒焼入れ品を提供するものである。   Therefore, in the present invention, the penetration rate of nitrogen into the workpiece surface can be improved, and a desired nitrogen penetration depth can be obtained in a short time. In other words, the nitrogen penetration depth can be improved in the same processing time. Nitrogen quenching method and nitrogen quenching product are provided.

上記課題を解決する浸窒焼入れ方法および浸窒焼入れ品は、以下の特徴を有する。
即ち、請求項１記載の如く、鉄または鉄合金にて構成されるワークに窒素を浸透拡散させるとともに焼入れを行う浸窒焼入れ方法であって、アンモニアガスが供給される熱処理炉内にワークを設置し、前記熱処理炉内の温度をワークのフェライト領域の所定の温度にまで昇温して所定時間保持した後、前記熱処理炉内の温度をワークのオーステナイト領域の温度にまで昇温して所定時間保持し、その後、前記ワークを急冷して焼入れを行う。 The nitriding and quenching method and the nitriding and quenching product for solving the above problems have the following characteristics.
That is, a nitriding quenching method in which nitrogen is infiltrated and diffused into a workpiece made of iron or an iron alloy and quenching is performed as set forth in claim 1, wherein the workpiece is installed in a heat treatment furnace to which ammonia gas is supplied. Then, the temperature in the heat treatment furnace is raised to a predetermined temperature in the ferrite region of the work and held for a predetermined time, and then the temperature in the heat treatment furnace is raised to the temperature in the austenite region of the work and for a predetermined time. Then, the workpiece is quenched and quenched.

また、請求項２記載の如く、前記熱処理炉内の温度をワークのフェライト領域の温度に保持する時間が、前記熱処理炉内の温度をワークのオーステナイト領域の温度に保持する時間よりも長く設定される。   Further, the time for maintaining the temperature in the heat treatment furnace at the temperature of the ferrite region of the workpiece is set longer than the time for maintaining the temperature in the heat treatment furnace at the temperature of the austenite region of the workpiece. The

また、請求項３記載の如く、前記ワークのフェライト領域の温度が４００℃〜５７０℃に設定され、前記ワークのオーステナイト領域の温度が６００℃〜８５０℃に設定される。   The temperature of the ferrite region of the workpiece is set to 400 ° C. to 570 ° C., and the temperature of the austenite region of the workpiece is set to 600 ° C. to 850 ° C.

また、請求項４記載の如く、鉄または鉄合金にて構成されるワークに窒素を浸透拡散させるとともに焼入れを行うことにより構成された浸窒焼入れ品であって、アンモニアガスが供給される熱処理炉内にワークを設置し、前記熱処理炉内の温度をワークのフェライト領域の所定の温度にまで昇温して所定時間保持した後、前記熱処理炉内の温度をワークのオーステナイト領域の温度にまで昇温して所定時間保持し、その後、前記ワークを急冷して焼入れすることにより構成された。   A heat treatment furnace to which ammonia gas is supplied, which is a nitrogen-quenched product constituted by diffusing and diffusing nitrogen into a workpiece made of iron or an iron alloy and quenching as in claim 4 A workpiece is placed inside, the temperature in the heat treatment furnace is raised to a predetermined temperature in the ferrite region of the work and held for a predetermined time, and then the temperature in the heat treatment furnace is raised to the temperature in the austenite region of the work. The workpiece was heated and held for a predetermined time, and then the workpiece was quenched and quenched.

また、請求項５記載の如く、前記熱処理炉内の温度をワークのフェライト領域の温度に保持する時間が、前記熱処理炉内の温度をワークのオーステナイト領域の温度に保持する時間よりも長く設定される。   Further, as described in claim 5, the time for maintaining the temperature in the heat treatment furnace at the temperature of the ferrite region of the workpiece is set longer than the time for maintaining the temperature in the heat treatment furnace at the temperature of the austenite region of the workpiece. The

また、請求項６記載の如く、前記ワークのフェライト領域の温度が４００℃〜５７０℃に設定され、前記ワークのオーステナイト領域の温度が６００℃〜８５０℃に設定される。   The temperature of the ferrite region of the workpiece is set to 400 ° C. to 570 ° C., and the temperature of the austenite region of the workpiece is set to 600 ° C. to 850 ° C.

本発明によれば、従来のように浸窒処理が行われる全ての時間にわたってワークをオーステナイト温度領域に維持した場合に比べて、同じ時間だけ熱処理を行ったときの、ワークへの窒素侵入深さを向上することが可能となる。
特に、フェライト温度領域での保持時間をオーステナイト温度領域での保持時間よりも長くすることで、ワークへの窒素侵入深さをより向上することが可能となる。 According to the present invention, compared with the conventional case where the work is kept in the austenite temperature range over the entire time when the nitriding treatment is performed, the depth of nitrogen penetration into the work when the heat treatment is performed for the same time. Can be improved.
In particular, by making the holding time in the ferrite temperature region longer than the holding time in the austenite temperature region, it is possible to further improve the nitrogen penetration depth into the workpiece.

次に、本発明を実施するための形態を、添付の図面を用いて説明する。   Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.

図１に示す熱処理炉１は、鉄または鉄合金にて構成されるワーク１１の表面に窒素を浸透拡散させるとともに焼入れを施す浸窒焼入処理を行うためのものである。
前記浸窒焼入れ処理は、前記熱処理炉１を用いた雰囲気熱処理により行われ、処理対象となるワーク１１は治具１２を介して熱処理炉１内に設置されている。 A heat treatment furnace 1 shown in FIG. 1 is for performing a nitrogen quenching process in which nitrogen is permeated and diffused on the surface of a workpiece 11 made of iron or an iron alloy and quenched.
The nitrogen quenching treatment is performed by atmospheric heat treatment using the heat treatment furnace 1, and a workpiece 11 to be treated is placed in the heat treatment furnace 1 via a jig 12.

また、前記熱処理炉１には、該熱処理炉１内にアンモニアガスなどのガスを供給するためのガス供給管３が接続されており、ワーク１１の浸窒焼入れ処理を行うときには、前記ガス供給管３を通じて熱処理炉１内に所定の流量のアンモニアガスなどが供給されるように構成されている。   The heat treatment furnace 1 is connected to a gas supply pipe 3 for supplying a gas such as ammonia gas into the heat treatment furnace 1. 3, a predetermined flow rate of ammonia gas or the like is supplied into the heat treatment furnace 1.

本例の場合、ワーク１１に対する浸窒焼入れ処理を行う際には、前記ガス供給管３を通じて所定流量のアンモニアガスおよび窒素ガスを熱処理炉１内に供給するようにしている。   In the case of this example, when performing the nitrogen quenching process on the workpiece 11, ammonia gas and nitrogen gas at a predetermined flow rate are supplied into the heat treatment furnace 1 through the gas supply pipe 3.

つまり、熱処理炉１によるワーク１１への浸窒焼入れ処理は、アンモニアガスおよび窒素ガスの雰囲気下で行われる。
また、熱処理炉１によりワーク１１へ浸窒焼入れ処理を行うときには、熱処理炉１内を所定の温度に加熱するが、熱処理炉１内の温度は制御装置２により制御される。 That is, the nitriding quenching process to the workpiece 11 by the heat treatment furnace 1 is performed in an atmosphere of ammonia gas and nitrogen gas.
Further, when the workpiece 11 is subjected to the nitriding and quenching process by the heat treatment furnace 1, the inside of the heat treatment furnace 1 is heated to a predetermined temperature, and the temperature in the heat treatment furnace 1 is controlled by the control device 2.

このように構成される熱処理炉１を用いて行う、ワーク１１に対する浸窒焼入れ処理の方法について、以下に説明する。   A method of nitriding and quenching the workpiece 11 performed using the heat treatment furnace 1 configured as described above will be described below.

浸窒焼入れ処理を行う場合、まずワーク１１を熱処理炉１内に設置し、前記ガス供給管３を通じて熱処理炉１内に所定の流量のアンモニアガスおよび窒素ガスを供給する。
次に、前記制御装置２により熱処理炉１内の温度を昇温させ、ワーク１１を加熱する。 When performing the nitriding quenching process, first, the work 11 is installed in the heat treatment furnace 1, and ammonia gas and nitrogen gas at a predetermined flow rate are supplied into the heat treatment furnace 1 through the gas supply pipe 3.
Next, the temperature in the heat treatment furnace 1 is raised by the control device 2 to heat the workpiece 11.

図２に示すように、ワーク１１は、まず所定の温度Ｔａになるまで加熱され、ワーク１１が温度Ｔａまで加熱されると、その温度Ｔａが所定の時間ｔ１だけ保持される。
このように、ワーク１１が温度Ｔａに保持されている間に、ワーク１１の表面からの窒素の侵入および拡散が行われる。
温度Ｔａを所定の時間ｔ１保持した後、熱処理炉１内の温度を昇温させて、ワーク１１を温度Ｔｂとなるまで加熱する。 As shown in FIG. 2, the workpiece 11 is first heated to a predetermined temperature Ta, and when the workpiece 11 is heated to the temperature Ta, the temperature Ta is held for a predetermined time t1.
Thus, while the workpiece | work 11 is hold | maintained at the temperature Ta, the penetration | invasion and diffusion of nitrogen from the surface of the workpiece | work 11 are performed.
After maintaining the temperature Ta for a predetermined time t1, the temperature in the heat treatment furnace 1 is raised, and the workpiece 11 is heated to the temperature Tb.

ワーク１１が温度Ｔｂに達すると、ワーク１１の温度Ｔａからの加熱を開始してから所定の時間ｔ２が経過するまで、その温度Ｔｂが保持される。
このように、ワーク１１が温度Ｔｂに保持されている間にも、ワーク１１の表面からの窒素の侵入および拡散が行われる。
その後、ワーク１１を熱処理炉１内から取り出し、急冷して焼入れを行う。 When the workpiece 11 reaches the temperature Tb, the temperature Tb is maintained until a predetermined time t2 elapses after the heating of the workpiece 11 from the temperature Ta is started.
In this manner, nitrogen enters and diffuses from the surface of the workpiece 11 while the workpiece 11 is held at the temperature Tb.
Thereafter, the workpiece 11 is taken out from the heat treatment furnace 1 and quenched and quenched.

このように、アンモニアガスおよび窒素ガスの雰囲気下でワーク１１に対して、温度Ｔａおよび温度Ｔｂの二段階の温度による熱処理ならびに急冷処理を行うことで、浸窒焼入れ品を得るようにしている。   In this way, a nitrogen-quenched product is obtained by performing heat treatment and quenching treatment on the workpiece 11 in two stages of temperature Ta and temperature Tb in the atmosphere of ammonia gas and nitrogen gas.

ここで、前記温度Ｔａはワーク１１がフェライト（α）の状態にあるフェライト温度領域の温度に設定され、前記温度Ｔｂはワーク１１がオーステナイト（γ）の状態にあるオーステナイト温度領域の温度に設定されている。
具体的には、前記温度Ｔａは４００℃〜５７０℃の範囲の温度に設定され、前記温度Ｔｂは６００℃〜８５０℃の範囲の温度に設定される。 Here, the temperature Ta is set to a temperature in the ferrite temperature region where the workpiece 11 is in the ferrite (α) state, and the temperature Tb is set to a temperature in the austenite temperature region where the workpiece 11 is in the austenite (γ) state. ing.
Specifically, the temperature Ta is set to a temperature in the range of 400 ° C. to 570 ° C., and the temperature Tb is set to a temperature in the range of 600 ° C. to 850 ° C.

前記温度Ｔａおよび温度Ｔｂを前述のように設定するのは以下の理由による。
つまり、前記フェライト温度領域においては、ワーク１１の温度が上昇するにつれてワーク１１表面からの窒素の拡散速度が増加するが、前記温度Ｔａを４００℃よりも低い温度に設定すると、ワーク１１表面からの窒素の拡散速度が遅くなり過ぎて、浸窒速度向上を効率的に行うことができないためである。
また、ワーク１１にオーステナイトが全く出現しない温度の上限が５７０℃であるため、前記温度Ｔａの上限を５７０℃に設定している。 The temperature Ta and the temperature Tb are set as described above for the following reason.
That is, in the ferrite temperature region, the diffusion rate of nitrogen from the surface of the work 11 increases as the temperature of the work 11 increases. However, if the temperature Ta is set to a temperature lower than 400 ° C., the temperature from the surface of the work 11 This is because the diffusion rate of nitrogen becomes too slow and the nitriding rate cannot be improved efficiently.
Moreover, since the upper limit of the temperature at which austenite does not appear at all in the work 11 is 570 ° C., the upper limit of the temperature Ta is set to 570 ° C.

一方、前記温度Ｔｂについては、ワーク１１に部分的にでもオーステナイトが出現する下限温度が６００℃であるため、温度Ｔｂの下限を６００℃に設定している。   On the other hand, regarding the temperature Tb, since the lower limit temperature at which austenite appears even partially on the workpiece 11 is 600 ° C., the lower limit of the temperature Tb is set to 600 ° C.

また、前記オーステナイト温度領域においても、ワーク１１の温度が上昇するにつれてワーク１１表面からの窒素の拡散速度が増加するが、８５０℃を超えるような高温になると、熱処理炉１内におけるアンモニアガスの分解が進行しすぎてアンモニアガスがワーク１１の表面に到達し難くなり、ワーク１１に対する浸窒速度が低下することになるため、温度Ｔｂの上限を８５０℃に設定している。   Also in the austenite temperature region, the diffusion rate of nitrogen from the surface of the work 11 increases as the temperature of the work 11 rises. However, when the temperature exceeds 850 ° C., the decomposition of ammonia gas in the heat treatment furnace 1 occurs. Progresses too much to make it difficult for the ammonia gas to reach the surface of the workpiece 11 and the nitriding rate for the workpiece 11 decreases, so the upper limit of the temperature Tb is set to 850 ° C.

また、前述のように、フェライト温度領域およびオーステナイト温度領域においては、ともにワーク１１の温度が上昇するにつれてワーク１１表面からの窒素の拡散速度が増加することとなっているが、図３に示すように、フェライト温度領域における窒素の拡散係数の方が、オーステナイト温度領域における窒素の拡散係数よりも相対的に大きくなっている。   Further, as described above, in the ferrite temperature region and the austenite temperature region, the diffusion rate of nitrogen from the surface of the work 11 increases as the temperature of the work 11 increases. As shown in FIG. In addition, the diffusion coefficient of nitrogen in the ferrite temperature region is relatively larger than the diffusion coefficient of nitrogen in the austenite temperature region.

例えば、オーステナイト温度領域にある８００℃での拡散係数Ｄｂよりも、フェライト温度領域にある５５０℃での拡散係数Ｄａのほうが大きな値となっている。   For example, the diffusion coefficient Da at 550 ° C. in the ferrite temperature region is larger than the diffusion coefficient Db at 800 ° C. in the austenite temperature region.

そこで、本例においては、窒素の拡散係数が大きなフェライト温度領域となる温度Ｔａにて所定の時間ｔ１だけ熱処理をしてワーク１１に対する浸窒・拡散を行ったのち、焼入れに必要なオーステナイト温度領域となる温度Ｔｂにて所定の時間ｔ２だけ熱処理を行い、その後ワーク１１を急冷して焼入れすることで、ワーク１１に対する浸窒焼入れ処理をおこなうようにしている。   Therefore, in this example, after the heat treatment is performed for a predetermined time t1 at the temperature Ta in which the diffusion coefficient of nitrogen is large and the nitrogen is diffused and diffused to the workpiece 11, the austenite temperature range necessary for quenching is obtained. A heat treatment is performed at a temperature Tb for a predetermined time t2, and then the workpiece 11 is quenched and quenched, thereby performing a nitriding quenching process on the workpiece 11.

このように、温度Ｔａでの熱処理と温度Ｔｂでの熱処理といったように、二段階の温度での熱処理を行うことで、従来のように浸窒処理が行われる全ての時間ｔ３にわたってワークをオーステナイト温度領域に維持した場合（図２における点線で示すグラフを参照）に比べて、同じ時間だけ熱処理を行ったときの、ワーク１１への窒素侵入深さを向上することが可能となっている。
つまり、ワークを全ての浸窒処理時間にわたってオーステナイト温度領域に維持した場合に比べて、短時間で所望の窒素侵入深さを得ることが可能となる。 In this way, by performing the heat treatment at the two-stage temperature, such as the heat treatment at the temperature Ta and the heat treatment at the temperature Tb, the workpiece is kept at the austenite temperature for all the time t3 in which the nitriding treatment is performed as in the prior art. Compared to the case of maintaining the region (see the graph shown by the dotted line in FIG. 2), it is possible to improve the nitrogen penetration depth into the workpiece 11 when the heat treatment is performed for the same time.
That is, it is possible to obtain a desired nitrogen penetration depth in a shorter time than when the workpiece is maintained in the austenite temperature region over the entire nitriding treatment time.

特に、本例の浸窒焼入れ処理においては、窒素の拡散係数が大きな前記温度Ｔａでの処理時間ｔ１が前記温度Ｔｂでの処理時間ｔ２よりも長くなるように設定しているため、ワーク１１への窒素侵入深さをより向上することが可能となっている。   In particular, in the nitriding quenching process of this example, the processing time t1 at the temperature Ta having a large nitrogen diffusion coefficient is set to be longer than the processing time t2 at the temperature Tb. It is possible to further improve the nitrogen penetration depth.

前記時間ｔ１の長さと前記時間ｔ２の長さとの割合は、例えばｔ１：ｔ２＝５：１に設定することができるが、これに限るものではなく、前記時間ｔ２は、少なくとも温度Ｔａからの加熱を開始したワーク１１が前記温度Ｔｂに達する時間が僅かでもあるように設定されればよい。   The ratio between the length of the time t1 and the length of the time t2 can be set to, for example, t1: t2 = 5: 1, but is not limited thereto, and the time t2 is at least heated from the temperature Ta. It may be set so that the time for the workpiece 11 that has started to reach the temperature Tb is very short.

次に、ワーク１１に対して二段階の温度Ｔａ・Ｔｂでの浸窒焼入れ処理を実際に行った場合の、ワーク１１の表面における窒素濃度および硬さの測定結果を図４、図５に示す。   Next, FIG. 4 and FIG. 5 show the measurement results of the nitrogen concentration and hardness on the surface of the workpiece 11 when the workpiece 11 is actually subjected to the nitriding quenching process at the two-stage temperature Ta · Tb. .

本例の浸窒焼入れ処理は、炭素鋼Ｓ３５Ｃにて構成されるワーク１１に対して行われ、前記温度Ｔａは５５０℃に、前記時間ｔ１は７５分に設定され、前記温度Ｔｂは８００℃に、前記時間ｔ２は１５分に設定されている。   Nitrogen quenching treatment of this example is performed on the workpiece 11 composed of carbon steel S35C, the temperature Ta is set to 550 ° C., the time t1 is set to 75 minutes, and the temperature Tb is set to 800 ° C. The time t2 is set to 15 minutes.

また、図４、図５には、従来の浸窒焼入れ処理のように、オーステナイト温度領域における一定の温度にて所定時間ｔ３だけ熱処理した場合の窒素濃度および硬さも示している。従来の浸窒焼入れ処理は８００℃の温度にて行われ、前記時間ｔ３は９０分（前記時間ｔ１と時間ｔ２との和に等しい）に設定されている。   4 and 5 also show the nitrogen concentration and hardness when the heat treatment is performed for a predetermined time t3 at a constant temperature in the austenite temperature range as in the conventional nitriding quenching process. The conventional nitriding quenching process is performed at a temperature of 800 ° C., and the time t3 is set to 90 minutes (equal to the sum of the time t1 and the time t2).

図４によれば、同じ時間だけ熱処理を行った場合でも、従来の浸窒焼入れ処理を施したワーク（図４にて点線で示すグラフ）よりも、本例の浸窒焼入れ処理を施したワーク１１（図４にて実践で示すグラフ）のほうが、表面からの距離が大きい箇所でも、すなわち表面から深い箇所でも高い窒素濃度を得ることが可能となっている。   According to FIG. 4, even when the heat treatment is performed for the same time, the workpiece subjected to the nitrogen quenching treatment of the present example rather than the workpiece subjected to the conventional nitriding quenching treatment (graph indicated by a dotted line in FIG. 4). 11 (a graph shown in practice in FIG. 4) can obtain a high nitrogen concentration even at a location where the distance from the surface is large, that is, at a location deep from the surface.

また、図５によれば、同じ時間だけ熱処理を行った場合でも、従来の浸窒焼入れ処理を施したワーク（図５にて点線で示すグラフ）よりも、本例の浸窒焼入れ処理を施したワーク１１（図５にて実践で示すグラフ）のほうが、表面からの距離が大きい箇所でも、すなわち表面から深い箇所でも高い硬度を得ることが可能となっている。   Further, according to FIG. 5, even when the heat treatment is performed for the same time, the nitrous quenching treatment of this example is performed more than the conventional nitrous quenching work (graph indicated by a dotted line in FIG. 5). The work 11 (the graph shown in practice in FIG. 5) can obtain higher hardness even at a location where the distance from the surface is large, that is, at a location deep from the surface.

このように、同一処理時間でも、本例の浸窒焼入れ処理の処理条件にて熱処理を行うほうが、従来の浸窒焼入れ処理の処理条件にて熱処理を行った場合よりも、深い硬化深さを得ることが可能となっている。   Thus, even with the same treatment time, the heat treatment under the nitriding quenching treatment conditions of this example has a deeper curing depth than when the heat treatment is carried out under the conventional nitriding quenching treatment conditions. It is possible to obtain.

熱処理炉を示す概略図である。It is the schematic which shows a heat treatment furnace. 熱処理炉により浸窒焼入れ処理を行う際の温度プロファイルを示す図である。It is a figure which shows the temperature profile at the time of performing a nitrogen quenching process with a heat treatment furnace. フェライト温度領域における窒素の拡散係数、およびオーステナイト温度領域における窒素の拡散係数を示す図である。It is a figure which shows the diffusion coefficient of nitrogen in a ferrite temperature range, and the diffusion coefficient of nitrogen in an austenite temperature range. 浸窒焼入れ処理を行ったワークの表面からの距離と窒素濃度との関係を示す図である。It is a figure which shows the relationship between the distance from the surface of the workpiece | work which performed the nitriding hardening process, and nitrogen concentration. 浸窒焼入れ処理を行ったワークの表面からの距離と硬度との関係を示す図である。It is a figure which shows the relationship between the distance from the surface of the workpiece | work which performed the nitriding hardening process, and hardness.

符号の説明Explanation of symbols

１ 熱処理炉
２ 制御装置
３ ガス供給管
１１ ワーク
１２ 治具 1 Heat Treatment Furnace 2 Control Device 3 Gas Supply Pipe 11 Work 12 Jig

Claims (6)

鉄または鉄合金にて構成されるワークに窒素を浸透拡散させるとともに焼入れを行う浸窒焼入れ方法であって、
アンモニアガスが供給される熱処理炉内にワークを設置し、
前記熱処理炉内の温度をワークのフェライト領域の所定の温度にまで昇温して所定時間保持した後、
前記熱処理炉内の温度をワークのオーステナイト領域の温度にまで昇温して所定時間保持し、
その後、前記ワークを急冷して焼入れを行う、
ことを特徴とする浸窒焼入れ方法。 Nitrogen quenching method in which nitrogen is infiltrated and diffused into a workpiece composed of iron or an iron alloy and quenching,
Install the work in the heat treatment furnace to which ammonia gas is supplied,
After raising the temperature in the heat treatment furnace to a predetermined temperature in the ferrite region of the workpiece and holding it for a predetermined time,
The temperature in the heat treatment furnace is raised to the temperature of the austenite region of the work and held for a predetermined time,
Then, quench the workpiece by quenching,
Nitrogen quenching method characterized by that. 前記熱処理炉内の温度をワークのフェライト領域の温度に保持する時間が、前記熱処理炉内の温度をワークのオーステナイト領域の温度に保持する時間よりも長く設定される、
ことを特徴とする請求項１に記載の浸窒焼入れ方法。 The time for maintaining the temperature in the heat treatment furnace at the temperature of the ferrite region of the workpiece is set longer than the time for maintaining the temperature in the heat treatment furnace at the temperature of the austenite region of the workpiece.
The nitriding and quenching method according to claim 1. 前記ワークのフェライト領域の温度が４００℃〜５７０℃に設定され、
前記ワークのオーステナイト領域の温度が６００℃〜８５０℃に設定される、
ことを特徴とする請求項１または請求項２に記載の浸窒焼入れ方法。 The temperature of the ferrite region of the workpiece is set to 400 ° C to 570 ° C,
The temperature of the austenite region of the workpiece is set to 600 ° C. to 850 ° C.,
The nitriding and quenching method according to claim 1 or 2, characterized in that 鉄または鉄合金にて構成されるワークに窒素を浸透拡散させるとともに焼入れを行うことにより構成された浸窒焼入れ品であって、
アンモニアガスが供給される熱処理炉内にワークを設置し、
前記熱処理炉内の温度をワークのフェライト領域の所定の温度にまで昇温して所定時間保持した後、
前記熱処理炉内の温度をワークのオーステナイト領域の温度にまで昇温して所定時間保持し、
その後、前記ワークを急冷して焼入れすることにより構成された、
ことを特徴とする浸窒焼入れ品。 Nitrogen-quenched products constructed by diffusing and diffusing nitrogen into a workpiece composed of iron or an iron alloy,
Install the work in the heat treatment furnace to which ammonia gas is supplied,
After raising the temperature in the heat treatment furnace to a predetermined temperature in the ferrite region of the workpiece and holding it for a predetermined time,
The temperature in the heat treatment furnace is raised to the temperature of the austenite region of the work and held for a predetermined time,
After that, it was configured by quenching and quenching the workpiece,
Nitrogen quenching product characterized by that. 前記熱処理炉内の温度をワークのフェライト領域の温度に保持する時間が、前記熱処理炉内の温度をワークのオーステナイト領域の温度に保持する時間よりも長く設定される、
ことを特徴とする請求項４に記載の浸窒焼入れ品。 The time for maintaining the temperature in the heat treatment furnace at the temperature of the ferrite region of the workpiece is set longer than the time for maintaining the temperature in the heat treatment furnace at the temperature of the austenite region of the workpiece.
The nitrocarburized product according to claim 4. 前記ワークのフェライト領域の温度が４００℃〜５７０℃に設定され、
前記ワークのオーステナイト領域の温度が６００℃〜８５０℃に設定される、
ことを特徴とする請求項４または請求項５に記載の浸窒焼入れ品。


The temperature of the ferrite region of the workpiece is set to 400 ° C to 570 ° C,
The temperature of the austenite region of the workpiece is set to 600 ° C. to 850 ° C.,
The nitrocarburized product according to claim 4 or 5, characterized by the above.


JP2008121592A 2008-05-07 2008-05-07 Nitriding quenching method and nitrided quenched part Pending JP2009270155A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012036495A (en) * 2010-07-16 2012-02-23 Sumitomo Metal Ind Ltd Method for manufacturing nitrided machine part
CN115627425A (en) * 2022-09-20 2023-01-20 武汉两仪材料有限公司 Metal material and preparation and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012036495A (en) * 2010-07-16 2012-02-23 Sumitomo Metal Ind Ltd Method for manufacturing nitrided machine part
CN115627425A (en) * 2022-09-20 2023-01-20 武汉两仪材料有限公司 Metal material and preparation and application thereof

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