JP2011012335A - Carburizing method - Google Patents

Carburizing method Download PDF

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JP2011012335A
JP2011012335A JP2009160038A JP2009160038A JP2011012335A JP 2011012335 A JP2011012335 A JP 2011012335A JP 2009160038 A JP2009160038 A JP 2009160038A JP 2009160038 A JP2009160038 A JP 2009160038A JP 2011012335 A JP2011012335 A JP 2011012335A
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workpiece
carburizing
work
edge portion
decarburization
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Koji Inagaki
功二 稲垣
Izuru Yamamoto
出 山本
Yasuhiro Koyama
泰浩 小山
Takeyuki Shimada
岳幸 島田
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Toyota Motor Corp
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Toyota Motor Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a carburizing method for controlling excess carburizing to a prescribed part of a workpiece that consists of a steel material, wherein the entire treatment time is shortened.SOLUTION: The carburizing method for impregnating the workpiece 1 consisting of a steel material with carbon and diffusing includes a decarburization process S1 of subjecting an optional part of the workpiece 1 to a decarbonizing treatment to obtain the workpiece 1 with the optional part decarbonized, and a carburization process S2 of subjecting the decarbonized workpiece 1 to a carburizing treatment.

Description

本発明は、鉄鋼素材からなるワークに炭素を浸透拡散させる、浸炭処理方法の技術に関する。   The present invention relates to a technique of a carburizing treatment method in which carbon is permeated and diffused into a workpiece made of a steel material.

従来、鉄鋼素材からなるワークに炭素を浸透拡散させてワークの表層部分を硬化させる浸炭処理方法に関する技術は公知となっている。当該浸炭処理方法によって炭素を浸透させたワークのエッジ部では、ワークの平坦部に比べてその炭素濃度が高くなっている。これは、ワークのエッジ部では、ワークの平坦部に比べて、ワーク内への炭素の拡散可能な領域が小さく、ワーク内へ炭素が拡散しにくいためである。
そして、ワークのエッジ部に炭素が過剰に浸透した場合には、当該ワークを冷却した際に、ワークのエッジ部にセメンタイトが過剰に残留することによって当該エッジ部はもろく割れやすくなり、ひいてはワークの品質が低下してしまうこととなる。
2. Description of the Related Art Conventionally, a technique related to a carburizing treatment method in which carbon is infiltrated and diffused into a workpiece made of a steel material to harden a surface layer portion of the workpiece is known. In the edge portion of the workpiece in which carbon is infiltrated by the carburizing method, the carbon concentration is higher than that of the flat portion of the workpiece. This is because the area where carbon can diffuse into the workpiece is smaller at the edge portion of the workpiece than the flat portion of the workpiece, and carbon is less likely to diffuse into the workpiece.
If carbon penetrates excessively into the edge of the workpiece, when the workpiece is cooled, excessive cementite remains at the edge of the workpiece, which makes the edge portion brittle and easily broken. Quality will fall.

また、鉄鋼素材からなるワークに炭素を浸透拡散させる浸炭処理方法であって、ワークに浸炭処理を行う浸炭工程と、浸炭処理が行われたワークに脱炭処理を行う脱炭工程と、脱炭処理が行われたワークに拡散処理を行う拡散工程と、を具備する浸炭処理方法の技術は公知となっている。例えば、特許文献1に示す如くである。
このような浸炭処理方法は、浸炭工程と拡散工程との間に脱炭工程を行うことによって、ワークのエッジ部への過剰浸炭を抑制し、炭素が浸透拡散されたワークの品質を向上させるものである。
Further, there are carburizing methods for infiltrating and diffusing carbon in a workpiece made of steel material, a carburizing step for carburizing the workpiece, a decarburizing step for decarburizing the workpiece that has been carburized, and a decarburizing method. The technique of the carburizing process method which comprises the diffusion process which performs a diffusion process to the workpiece | work in which the process was performed is known. For example, as shown in Patent Document 1.
Such a carburizing method is to improve the quality of a work in which carbon is permeated and diffused by suppressing a decarburization process between the carburizing process and the diffusion process, thereby suppressing excessive carburization to the edge of the work. It is.

特開2004−115893号公報JP 2004-115893 A

しかしながら、当該ワークのエッジ部への過剰浸炭を抑制した浸炭処理方法の脱炭工程は、浸炭処理が行われたワーク全体に脱炭処理を行うものである。つまり当該浸炭処理方法の脱炭工程では、脱炭処理が行われる必要の無い箇所(ワークの平面部)まで脱炭処理が行われている。
このため、当該浸炭処理方法の脱炭工程では、ワークの脱炭処理が行われる必要の無い箇所において、その炭素濃度が所望の濃度より低くなってしまう場合がある。このような場合には、当該脱炭処理が行われる必要の無い箇所の炭素濃度を所望の濃度となるように、前記脱炭処理が行われたワークに改めて浸炭処理を行う必要がある。
もっとも、当該浸炭処理方法の浸炭工程は、ワーク全体に浸炭処理を行うものである。つまり前記脱炭工程の後に行われる浸炭工程は、脱炭処理が行われる必要のある箇所(ワークのエッジ部)まで浸炭処理が行われている。
このため、当該改めて浸炭処理が行われたワークの脱炭処理が行われる必要のある箇所において、その炭素濃度が所望の濃度より高くなってしまう場合がある。このような場合には、当該脱炭処理が行われる必要のある箇所の炭素濃度を所望の濃度となるように、前記浸炭処理が行われたワークにさらに脱炭処理を行う必要がある。
However, the decarburization process of the carburizing method that suppresses excessive carburization to the edge portion of the workpiece performs the decarburizing process on the entire workpiece that has been carburized. That is, in the decarburization process of the carburizing method, the decarburization process is performed up to the place where the decarburization process does not need to be performed (the plane portion of the workpiece).
For this reason, in the decarburization process of the carburizing method, the carbon concentration may be lower than a desired concentration at a location where the workpiece needs not be decarburized. In such a case, it is necessary to perform a carburizing process again on the work on which the decarburizing process has been performed so that the carbon concentration at a place where the decarburizing process does not need to be performed becomes a desired concentration.
However, the carburizing step of the carburizing method involves carburizing the entire workpiece. That is, in the carburizing process performed after the decarburizing process, the carburizing process is performed up to the place where the decarburizing process needs to be performed (the edge portion of the workpiece).
For this reason, the carbon concentration may be higher than a desired concentration at a location where the decarburization processing of the workpiece that has been subjected to the carburizing process again needs to be performed. In such a case, it is necessary to further decarburize the work on which the carburizing process has been performed so that the carbon concentration at the location where the decarburizing process needs to be performed becomes a desired concentration.

このように当該浸炭処理方法では、ワークにおける所定の部位における炭素濃度を所望の濃度にするためには、脱炭処理と浸炭処理とを複数回繰り返し行う必要があり、結果として浸炭処理方法における全体の処理時間が長くなるという問題があった。   As described above, in the carburizing method, it is necessary to repeatedly perform the decarburizing process and the carburizing process a plurality of times in order to obtain a desired carbon concentration at a predetermined part of the work, and as a result, the entire carburizing process method is performed. There is a problem that the processing time becomes longer.

本発明は以上のような状況に鑑みてなされたものであり、ワークの所定部位への過剰浸炭を抑制した浸炭処理方法における全体の処理時間を短縮した浸炭処理方法を提供することを課題とする。   This invention is made | formed in view of the above situations, and makes it a subject to provide the carburizing processing method which shortened the whole processing time in the carburizing processing method which suppressed the excessive carburizing to the predetermined site | part of a workpiece | work. .

本発明の解決しようとする課題は以上の如くであり、次にこの課題を解決するための手段を説明する。   The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

即ち、請求項1においては、鉄鋼素材からなるワークに炭素を浸透拡散させる、浸炭処理方法であって、前記ワークにおける任意の一部の箇所に脱炭処理を行って、該任意の一部の箇所に脱炭処理が行われたワークを得る、脱炭工程と、前記脱炭処理が行われたワークに浸炭処理を行う、浸炭工程と、を具備するものである。   That is, in Claim 1, it is a carburizing treatment method in which carbon penetrates and diffuses into a workpiece made of a steel material, and decarburization treatment is performed at any part of the workpiece, and the arbitrary part of the carburizing treatment is performed. A decarburization step for obtaining a workpiece subjected to decarburization treatment at a location and a carburization step for performing a carburization treatment on the workpiece subjected to the decarburization treatment are provided.

本発明の効果として、以下に示すような効果を奏する。   As effects of the present invention, the following effects can be obtained.

即ち、本発明に係る浸炭処理方法によれば、過剰浸炭を抑制した浸炭処理方法における全体の処理時間を短縮することができる。   That is, according to the carburizing method according to the present invention, the overall processing time in the carburizing method that suppresses excessive carburizing can be shortened.

本発明に係る浸炭処理方法の実施形態におけるフロー図。The flowchart in embodiment of the carburizing process method which concerns on this invention. 本発明に係る浸炭処理方法の第一実施形態に用いられるワークの斜視図。The perspective view of the workpiece | work used for 1st embodiment of the carburizing method concerning this invention. (a)はワークを加熱する状態を示す模式図、(b)は脱炭工程を行う温度プロファイルを示す図。(A) is a schematic diagram which shows the state which heats a workpiece | work, (b) is a figure which shows the temperature profile which performs a decarburization process. (a)は加熱されるワークの温度状態を示す図、(b)は加熱後のワークにおける炭素濃度分布を示す図。(A) is a figure which shows the temperature state of the workpiece | work heated, (b) is a figure which shows carbon concentration distribution in the workpiece | work after a heating. (a)は浸炭工程を行う温度プロファイルを示す図、(b)浸炭工程後のワークにおける炭素濃度分布を示す図。(A) is a figure which shows the temperature profile which performs a carburizing process, (b) The figure which shows carbon concentration distribution in the workpiece | work after a carburizing process. (a)従来の浸炭処理方法を行う温度プロファイルを示す図、(b)従来の浸炭処理方法における処理時間と、本発明に係る浸炭処理方法における処理時間とを示した図。(A) The figure which shows the temperature profile which performs the conventional carburizing processing method, (b) The figure which showed the processing time in the conventional carburizing processing method, and the processing time in the carburizing processing method which concerns on this invention. 本発明に係る浸炭処理方法の第二実施形態に用いられるワークの斜視図。The perspective view of the workpiece | work used for 2nd embodiment of the carburizing method concerning this invention. (a)はワークを加熱する状態を示す模式図、(b)は脱炭工程を行う温度プロファイルを示す図。(A) is a schematic diagram which shows the state which heats a workpiece | work, (b) is a figure which shows the temperature profile which performs a decarburization process. (a)は加熱されるワークの温度状態を示す図、(b)は加熱後のワークにおける炭素濃度分布を示す図。(A) is a figure which shows the temperature state of the workpiece | work heated, (b) is a figure which shows carbon concentration distribution in the workpiece | work after a heating. 浸炭工程後のワークにおける硬さ分布を示す図。The figure which shows the hardness distribution in the workpiece | work after a carburizing process.

次に、本発明に係る浸炭処理方法の第一実施形態を、図1から図6を用いて説明する。
本発明の第一実施形態における浸炭処理方法は、ワークに炭素を浸透拡散させる浸炭処理方法であって、図1に示す如く、脱炭工程S1と、浸炭工程S2と、を具備する。なお以下において、本実施形態の浸炭処理方法でワークに浸透拡散させる炭素の浸炭深さは、ワークの表面から0.5mmであるものとして説明する。
Next, a first embodiment of the carburizing method according to the present invention will be described with reference to FIGS.
The carburizing method according to the first embodiment of the present invention is a carburizing method for permeating and diffusing carbon in a workpiece, and includes a decarburizing step S1 and a carburizing step S2, as shown in FIG. In the following description, it is assumed that the carburization depth of carbon to be diffused into the workpiece by the carburizing method of the present embodiment is 0.5 mm from the surface of the workpiece.

脱炭工程S1について説明する。脱炭工程S1とは、ワークにおける任意の一部の箇所に脱炭処理を行って、該任意の一部の箇所に脱炭処理が行われたワークを得る工程である。   Decarburization process S1 is demonstrated. The decarburization step S1 is a step of performing a decarburization process on an arbitrary part of the work to obtain a work subjected to the decarburization process on the arbitrary part of the work.

ここで、ワーク1とは、図2に示す如く、鉄鋼素材からなる浸炭処理の対象物を示し、上下方向に長い直方体に形成される。
また、ワーク1はエッジ部10と平坦部11とを有する。ワーク1のエッジ部10とは、ワーク1における面体と面体との各境界部分のエッジ状の部分を示す。ワーク1の平坦部11とは、ワーク1における側面のうち、エッジ部10以外の部分である平坦状の部分を示す。
Here, as shown in FIG. 2, the workpiece 1 is an object of carburizing treatment made of a steel material, and is formed in a rectangular parallelepiped that is long in the vertical direction.
The work 1 has an edge portion 10 and a flat portion 11. The edge portion 10 of the workpiece 1 indicates an edge-shaped portion of each boundary portion between the face body and the face body in the workpiece 1. The flat part 11 of the work 1 indicates a flat part which is a part other than the edge part 10 among the side surfaces of the work 1.

脱炭工程S1の脱炭処理は、ワーク1における上面と各側面とで構成するエッジ部(以下、上エッジ部12と称する)、及び、ワーク1における下面と各側面とで構成するエッジ部(下エッジ部13と称する)を、それぞれ所定の条件で加熱することによって、上エッジ部12及び下エッジ部13を脱炭(上エッジ部12及び下エッジ部13の炭素濃度を低く)するものである。なお、図4及び図5中のEは、ワークのエッジ部10のうち脱炭処理が行われる上エッジ部12及び/又は下エッジ部13の状態を示している。また、図4及び図5中の部分Fは、ワークの平坦部11の状態を示している。   The decarburization process in the decarburization step S1 includes an edge portion (hereinafter, referred to as an upper edge portion 12) configured by the upper surface and each side surface of the work 1, and an edge portion (hereinafter, referred to as the upper edge portion 12) ( The upper edge portion 12 and the lower edge portion 13 are decarburized (the carbon concentrations of the upper edge portion 12 and the lower edge portion 13 are reduced) by heating each of the lower edge portions 13 under a predetermined condition. is there. 4 and 5 indicates the state of the upper edge portion 12 and / or the lower edge portion 13 where the decarburization process is performed in the edge portion 10 of the workpiece. Moreover, the part F in FIG.4 and FIG.5 has shown the state of the flat part 11 of a workpiece | work.

ワーク1の上エッジ部12及び下エッジ部13との加熱は、まず、図3(a)に示す如く、ワーク1の上エッジ部12の外周、及び、ワーク1の下エッジ部13の外周に高周波加熱装置のコイル3・3をそれぞれ配置する。そして、当該ワーク1の上エッジ部12及びワーク1の下エッジ部13を、自然雰囲気中で高周波加熱装置によって加熱する。
前記高周波加熱装置によるワーク1の上エッジ部12及び下エッジ部13の加熱は、図3(b)に示す如く、ワーク1の上エッジ部12及び下エッジ部13を900℃に昇温させ、当該900℃となった状態を60秒間保持することによって行われる。そして、係る加熱が終了した後、ワーク1を空冷する。
As shown in FIG. 3A, the heating of the upper edge portion 12 and the lower edge portion 13 of the work 1 is first performed on the outer periphery of the upper edge portion 12 of the work 1 and the outer periphery of the lower edge portion 13 of the work 1. The coils 3 and 3 of the high frequency heating device are respectively arranged. And the upper edge part 12 of the said workpiece | work 1 and the lower edge part 13 of the workpiece | work 1 are heated with a high frequency heating apparatus in natural atmosphere.
The heating of the upper edge portion 12 and the lower edge portion 13 of the work 1 by the high-frequency heating device is performed by raising the temperature of the upper edge portion 12 and the lower edge portion 13 of the work 1 to 900 ° C. as shown in FIG. This is performed by holding the state at 900 ° C. for 60 seconds. And after the heating which concerns is complete | finished, the workpiece | work 1 is air-cooled.

脱炭工程S1が行われているワーク1では、図4(a)に示す如く、その上エッジ部12及び下エッジ部13の温度は、900℃まで上昇し、当該900℃を60秒間保持し、その後下降することとなる。
また、脱炭工程S1が施されたワーク1では、図4(b)に示す如く、その上エッジ部12及び下エッジ部13の炭素濃度は、表面からの距離0.3mmより深いところでは略3%で一定であるが、表面からの距離0.3mmから表面に行くにしたがって減少し、当該表面では略0.1%となっている。つまり、脱炭工程S1が行われたワーク1では、その上エッジ部12及び下エッジ部13の炭素濃度は、表面に行くにしたがって低くなっている。
このようにしてワーク1の上エッジ部12及び下エッジ部13を加熱することによって、当該上エッジ部12及び下エッジ部13が酸化して、上エッジ部12及び下エッジ部13内の炭素が外部に拡散し、その炭素濃度が低くなっている。つまり、ワーク1の上エッジ部12及び下エッジ部13を加熱することによって、当該上エッジ部12及び下エッジ部13は脱炭されている。
In the workpiece 1 in which the decarburization step S1 is performed, as shown in FIG. 4A, the temperature of the upper edge portion 12 and the lower edge portion 13 rises to 900 ° C., and the 900 ° C. is held for 60 seconds. Then, it will descend.
Moreover, in the workpiece 1 subjected to the decarburization step S1, as shown in FIG. 4B, the carbon concentrations of the upper edge portion 12 and the lower edge portion 13 are substantially not deeper than the distance of 0.3 mm from the surface. Although it is constant at 3%, it decreases from the distance 0.3 mm from the surface toward the surface, and is about 0.1% on the surface. That is, in the workpiece 1 on which the decarburization step S1 has been performed, the carbon concentrations of the upper edge portion 12 and the lower edge portion 13 become lower toward the surface.
By heating the upper edge portion 12 and the lower edge portion 13 of the workpiece 1 in this way, the upper edge portion 12 and the lower edge portion 13 are oxidized, and carbon in the upper edge portion 12 and the lower edge portion 13 is changed. It diffuses to the outside and its carbon concentration is low. That is, the upper edge portion 12 and the lower edge portion 13 are decarburized by heating the upper edge portion 12 and the lower edge portion 13 of the workpiece 1.

もっとも、脱炭工程S1が行われたワーク1であっても、図4(a)に示す如く、その平坦部11の温度は、ワーク1の上エッジ部12及び下エッジ部13を加熱する前の温度とほぼ変化なく一定となっている。
また、脱炭工程S1が行われたワーク1では、図4(b)に示す如く、その平坦部11の炭素濃度は、表面からの距離0.3mmより深いところであっても、表面からの距離0.3mmから表面であっても、略0.3%で殆ど一定となっている。
But even if it is the workpiece | work 1 in which the decarburization process S1 was performed, as shown to Fig.4 (a), the temperature of the flat part 11 is before heating the upper edge part 12 and the lower edge part 13 of the workpiece | work 1. The temperature is constant with almost no change.
Further, in the workpiece 1 subjected to the decarburization step S1, as shown in FIG. 4B, the carbon concentration of the flat portion 11 is a distance from the surface even if the carbon concentration is deeper than a distance of 0.3 mm from the surface. Even from the surface of 0.3 mm, it is almost constant at about 0.3%.

このように、脱炭工程S1では、ワーク1の上エッジ部12及び下エッジ部13には脱炭処理が行われているが、ワーク1の平坦部11には脱炭処理が行われていない。つまり、脱炭工程S1では、ワーク1を全体的に加熱してこれを脱炭処理するものではなく、
過剰浸炭が生じやすい上エッジ部12や下エッジ部13などのワーク1の局所(任意の一部の箇所)を加熱して当該局所(任意の一部の箇所)に脱炭処理を行うものである。
Thus, in the decarburization step S1, the decarburization process is performed on the upper edge portion 12 and the lower edge portion 13 of the work 1, but the decarburization process is not performed on the flat portion 11 of the work 1. . That is, in the decarburization step S1, the work 1 is not entirely heated and decarburized,
A part (arbitrary part) of the workpiece 1 such as the upper edge part 12 and the lower edge part 13 where excessive carburization is likely to occur is heated to decarburize the local part (arbitrary part). is there.

浸炭工程S2について説明する。浸炭工程S2とは、脱炭工程S1にて脱炭処理が行われたワーク1に浸炭処理を行う工程である。
浸炭工程S2は、所定のワークに炭素を浸透拡散させる浸炭用の処理炉を用いて行う。浸炭工程S2では、炭酸水素系ガス雰囲気中の前記処理炉内に脱炭工程S1にて脱炭処理が行われたワーク1を配置してこれを加熱し、その後これを冷却(焼入れ)することによって、ワーク1の全体に対して浸炭処理を行う。
The carburizing step S2 will be described. The carburizing step S2 is a step of carburizing the workpiece 1 that has been decarburized in the decarburizing step S1.
The carburizing step S2 is performed using a carburizing treatment furnace that allows carbon to permeate and diffuse into a predetermined workpiece. In the carburizing step S2, the work 1 that has been decarburized in the decarburizing step S1 is placed in the processing furnace in a hydrogen carbonate gas atmosphere and heated, and then cooled (quenched). Thus, carburizing treatment is performed on the entire workpiece 1.

前記処理炉によるワーク1の加熱は、図5(a)に示す如く、ワーク1の温度を950℃に昇温させ、ワーク1が950℃となった状態を660秒間保持することによって行う。ワーク1が950℃となった状態を保持する時間:660秒は、炭素を浸透させる時間:240秒と、浸透した炭素を拡散させる時間:420秒との合計の時間であって、ワーク1に浸透拡散させる炭素の浸炭深さをワークの表面から0.5mmとするための処理時間である。   As shown in FIG. 5A, the workpiece 1 is heated by the processing furnace by raising the temperature of the workpiece 1 to 950 ° C. and holding the workpiece 1 at 950 ° C. for 660 seconds. The time when the workpiece 1 is kept at 950 ° C .: 660 seconds is the total time of carbon penetration time: 240 seconds and diffusion time of the penetrated carbon: 420 seconds. This is the processing time for setting the carburizing depth of carbon to be permeated and diffused to 0.5 mm from the surface of the workpiece.

このようにして浸炭工程S2が行われたワーク1では、図5(b)に示す如く、ワーク1の上エッジ部12及び下エッジ部13の炭素濃度と、ワーク1の平坦部11の炭素濃度とが略同一となっている。つまり、このようにして浸炭工程S2が行われたワーク1の上エッジ部12及び下エッジ部13には、セメンタイトが無い状態となっている。
したがって、本実施形態における浸炭処理方法によれば、ワーク1のエッジ部10(上エッジ部12及び下エッジ部13)に過剰に浸炭が浸透することを抑制して、ワーク1のエッジ部10(上エッジ部12及び下エッジ部13)にセメンタイトが過剰に残留することを抑制し、ワークの品質を向上させることができる。
In the workpiece 1 subjected to the carburizing step S2 in this way, as shown in FIG. 5B, the carbon concentration of the upper edge portion 12 and the lower edge portion 13 of the workpiece 1 and the carbon concentration of the flat portion 11 of the workpiece 1 Are substantially the same. That is, the upper edge portion 12 and the lower edge portion 13 of the workpiece 1 subjected to the carburizing step S2 in this way are in a state where there is no cementite.
Therefore, according to the carburizing method according to the present embodiment, excessive penetration of carburizing into the edge portion 10 (the upper edge portion 12 and the lower edge portion 13) of the workpiece 1 is suppressed, and the edge portion 10 ( It is possible to suppress the cementite from remaining excessively in the upper edge portion 12 and the lower edge portion 13) and improve the quality of the workpiece.

ここで、図6(a)に示す如く、従来における浸炭処理方法であって、ワークにおける所定の部位における炭素濃度を所望の濃度にするために、脱炭処理と浸炭処理とを複数回繰り返した後に拡散処理を行う必要がある浸炭処理方法によって、ワークに浸透拡散させる炭素の浸炭深さをワークの表面から0.5mmとするためには、ワーク1の温度を950℃に昇温させ、ワーク1が950℃となった状態を1400秒間保持する必要がある。
もっとも、本実施形態の浸炭処理方法によって、ワークに浸透拡散させる炭素の浸炭深さをワークの表面から0.5mmとするためには、720秒(脱炭工程S1:60秒と浸炭工程S2:660秒との合計時間)で行うことができる。
つまり、本実施形態の浸炭処理方法によれば、従来の浸炭処理方法の処理時間に比べて略50%の処理時間で浸炭処理を行うことができる(図6(b)参照)。
したがって本実施形態の浸炭処理方法によれば、ワーク1の所定部位への過剰浸炭を抑制するとともに、浸炭処理方法における全体の処理時間を短縮することができる。
Here, as shown in FIG. 6A, in the conventional carburizing method, the decarburizing process and the carburizing process are repeated a plurality of times in order to obtain a desired carbon concentration at a predetermined portion of the workpiece. In order to set the carburizing depth of carbon to be infiltrated and diffused into the workpiece to 0.5 mm from the surface of the workpiece by a carburizing method that requires diffusion treatment later, the temperature of the workpiece 1 is increased to 950 ° C. It is necessary to hold the state where 1 becomes 950 ° C. for 1400 seconds.
However, in order to set the carburizing depth of carbon to be infiltrated and diffused into the workpiece to 0.5 mm from the surface of the workpiece by the carburizing method of this embodiment, 720 seconds (decarburization step S1: 60 seconds and carburizing step S2: Total time of 660 seconds).
That is, according to the carburizing method of the present embodiment, the carburizing process can be performed in approximately 50% of the processing time compared to the processing time of the conventional carburizing method (see FIG. 6B).
Therefore, according to the carburizing method of the present embodiment, it is possible to suppress excessive carburizing of the workpiece 1 to a predetermined part and shorten the overall processing time in the carburizing method.

次に、本発明に係る浸炭処理方法の第二実施形態を、図7から図10を用いて説明する。
なお、本実施形態における浸炭処理方法は、第一実施形態における浸炭処理方法と同様の工程で行われる部分があるため、本実施形態における浸炭処理方法の説明は、第一実施形態における浸炭処理方法と同様の工程で行われる部分については適宜省略し、第一実施形態における浸炭処理方法と異なる工程で行われる部分を中心に説明する。
Next, a second embodiment of the carburizing method according to the present invention will be described with reference to FIGS.
In addition, since the carburizing method in this embodiment has a part performed in the process similar to the carburizing method in 1st embodiment, description of the carburizing method in this embodiment is the carburizing method in 1st embodiment. The parts performed in the same steps as those described above will be omitted as appropriate, and the description will focus on the parts performed in the steps different from the carburizing method in the first embodiment.

まず、本実施形態に用いられるワーク2について説明する。
ワーク2は、図7に示す如く、鉄鋼素材からなる浸炭処理の対象物を示し、硬さ必要部20と硬さ不要部21とから構成される。ワーク2の硬さ必要部20とは、本実施形態における浸炭処理方法によってその表層部分を硬化させたい部分をいい、円柱状に形成される。ワーク2の硬さ不要部21とは、本実施形態における浸炭処理方法によってその表層部分を硬化させたくない部分をいい、前記硬さ必要部20の底面よりも大きい上面を備える円柱状に形成される。つまり、硬さ不要部21は硬さ必要部20よりも大径の円柱状に形成されている。そして、ワーク2は、硬さ必要部20の底面と硬さ不要部21の上面とを互いに一致させ、これらを一体的にして構成されている。
First, the workpiece | work 2 used for this embodiment is demonstrated.
As shown in FIG. 7, the workpiece 2 is an object of carburizing treatment made of a steel material, and includes a hardness required portion 20 and a hardness unnecessary portion 21. The hardness required portion 20 of the workpiece 2 refers to a portion where the surface layer portion is desired to be hardened by the carburizing method in the present embodiment, and is formed in a cylindrical shape. The hardness unnecessary portion 21 of the workpiece 2 is a portion where the surface layer portion is not desired to be hardened by the carburizing method in the present embodiment, and is formed in a columnar shape having a larger upper surface than the bottom surface of the hardness required portion 20. The That is, the hardness unnecessary portion 21 is formed in a cylindrical shape having a larger diameter than the hardness required portion 20. And the workpiece | work 2 makes the bottom face of the hardness required part 20 and the upper surface of the hardness unnecessary part 21 mutually correspond, and these are comprised integrally.

脱炭工程S1の脱炭処理は、ワーク2の硬さ不要部21を所定の条件で加熱することによって、当該硬さ不要部21を脱炭(硬さ不要部21の炭素濃度を低く)するものである。なお、図9及び図10中のNは、ワーク2の硬さ必要部20の状態を示している。また、図9及び図10中のUは、ワーク2の硬さ不要部21の状態を示している。   In the decarburization process of the decarburization step S1, the hardness unnecessary portion 21 of the work 2 is heated under a predetermined condition to decarburize the hardness unnecessary portion 21 (the carbon concentration of the hardness unnecessary portion 21 is reduced). Is. Note that N in FIGS. 9 and 10 indicates the state of the hardness required portion 20 of the workpiece 2. Moreover, U in FIG.9 and FIG.10 has shown the state of the hardness unnecessary part 21 of the workpiece | work 2. In FIG.

ワーク2の硬さ不要部21の加熱は、まず、図8(a)に示す如く、ワーク2の硬さ不要部21の外周に高周波加熱装置のコイル3を配置する。そして、当該ワーク2の硬さ不要部21を、自然雰囲気中で高周波加熱装置によって加熱する。
前記高周波加熱装置によるワーク2の硬さ不要部21の加熱は、図8(b)に示す如く、ワーク2の硬さ不要部21を900℃に昇温させ、当該900℃となった状態を180秒間保持することによって行われる。そして、係る加熱が終了した後、ワーク2を空冷する。
For heating the hardness unnecessary portion 21 of the work 2, first, as shown in FIG. 8A, the coil 3 of the high-frequency heating device is disposed on the outer periphery of the hardness unnecessary portion 21 of the work 2. And the hardness unnecessary part 21 of the said workpiece | work 2 is heated with a high frequency heating apparatus in natural atmosphere.
As shown in FIG. 8B, heating of the work 2 unnecessary hardness portion 21 by the high-frequency heating device is performed by raising the temperature of the work 2 hardness unnecessary portion 21 to 900 ° C. and reaching the 900 ° C. state. This is done by holding for 180 seconds. And after the heating which concerns is complete | finished, the workpiece | work 2 is air-cooled.

脱炭工程S1が行われているワーク2では、図9(a)に示す如く、その硬さ不要部21の温度は、900℃まで上昇し、当該900℃を180秒間保持し、その後下降することとなる。
また、脱炭工程S1が施されたワーク2では、図9(b)に示す如く、その硬さ不要部21の炭素濃度は、表面からの距離0.3mmより深いところでは略3%で一定であるが、表面からの距離0.3mmから表面に行くにしたがって減少し、当該表面では略0.1%となっている。つまり、脱炭工程S1が行われたワーク2では、その硬さ不要部21の炭素濃度は、表面に行くにしたがって低くなっている。
このようにしてワーク2の硬さ不要部21を加熱することによって、当該硬さ不要部21が酸化して、硬さ不要部21内の炭素が外部に拡散し、その炭素濃度が低くなっている。つまり、ワーク2の硬さ不要部21を加熱することによって、当該硬さ不要部21は脱炭されている。
In the workpiece 2 in which the decarburization step S1 is performed, as shown in FIG. 9A, the temperature of the hardness unnecessary portion 21 rises to 900 ° C., holds the 900 ° C. for 180 seconds, and then falls. It will be.
Moreover, in the workpiece 2 subjected to the decarburization step S1, as shown in FIG. 9B, the carbon concentration of the hardness unnecessary portion 21 is constant at about 3% when the distance from the surface is deeper than 0.3 mm. However, the distance decreases from 0.3 mm from the surface toward the surface, and is approximately 0.1% on the surface. That is, in the workpiece 2 on which the decarburization step S1 has been performed, the carbon concentration of the hardness unnecessary portion 21 becomes lower toward the surface.
By heating the hardness unnecessary portion 21 of the workpiece 2 in this way, the hardness unnecessary portion 21 is oxidized, and the carbon in the hardness unnecessary portion 21 is diffused to the outside, and the carbon concentration is lowered. Yes. That is, by heating the hardness unnecessary portion 21 of the work 2, the hardness unnecessary portion 21 is decarburized.

もっとも、脱炭工程S1が行われたワーク2であっても、図9(a)に示す如く、その硬さ必要部20の温度は、ワーク2の硬さ不要部21を加熱する前の温度とほぼ変化なく一定となっている。
また、脱炭工程S1が行われたワーク2では、図9(b)に示す如く、その硬さ必要部20の炭素濃度は、表面からの距離0.3mmより深いところであっても、表面からの距離0.3mmから表面であっても、略0.3%で殆ど一定となっている。
But even if it is the workpiece | work 2 in which the decarburization process S1 was performed, as shown to Fig.9 (a), the temperature of the hardness required part 20 is the temperature before heating the hardness unnecessary part 21 of the workpiece | work 2. And is almost unchanged.
Moreover, in the workpiece 2 that has undergone the decarburization step S1, as shown in FIG. 9B, the carbon concentration of the required hardness portion 20 is from the surface even if it is deeper than a distance of 0.3 mm from the surface. Even from the distance of 0.3 mm, the surface is almost constant at approximately 0.3%.

このように、脱炭工程S1では、ワーク2の硬さ不要部21には脱炭処理が行われているが、ワーク2の硬さ必要部20には脱炭処理が行われていない。つまり、脱炭工程S1では、ワーク2を全体的に加熱してこれを脱炭処理するものではなく、硬さ不要部21などのワーク2の局所(任意の一部の箇所)を加熱して当該局所(任意の一部の箇所)に脱炭処理を行うものである。   Thus, in the decarburization process S1, the decarburization process is performed on the hardness unnecessary portion 21 of the work 2, but the decarburization process is not performed on the hardness required portion 20 of the work 2. That is, in the decarburization step S1, the work 2 is not heated entirely and decarburized, but the local part (arbitrary part) of the work 2 such as the hardness unnecessary portion 21 is heated. The decarburization process is performed on the local area (arbitrary part).

このようにして脱炭工程S1が行われたワーク2について浸炭工程S2を行い、ワーク2の全体に対して浸炭処理を施す。
浸炭工程S2が行われたワーク2では、図10に示す如く、脱炭処理が施されていない硬さ必要部20は、通常の浸炭処理と同様に硬化することとなるが、脱炭処理が施された硬さ不要部21は、脱炭処理が行われているため、当該硬さ必要部20ほど硬化されていないこととなる。
このようにして、本実施形態の浸炭処理方法によれば、ワーク2の局所(硬さ不要部21)に脱炭工程S1を行って、さらにこれに浸炭工程S2を行うことにより、ワーク2において硬化した部分と、硬化していない部分とを容易に作り出すことができる。
また、本実施形態の浸炭処理方法により硬化した部分(硬さ必要部20)と硬化していない部分(硬さ不要部21)とを容易に作り出したワーク2では、その後の工程において、ワーク2の硬化していない部分(硬さ不要部21)の切削や研磨等の機械加工が容易となり、当該機械加工を行う費用を削減することができる。
また、本実施形態における浸炭処理方法によれば、ワーク2の硬さ不要部21に防炭処理を行うことなくこれを硬化させないようにすることができるため、防炭処理を行う費用を削減することができる。
In this way, the carburizing step S2 is performed on the workpiece 2 on which the decarburizing step S1 has been performed, and the entire workpiece 2 is subjected to carburizing treatment.
In the workpiece 2 that has been subjected to the carburizing step S2, as shown in FIG. 10, the hardness required portion 20 that has not been subjected to the decarburizing process is cured in the same manner as the normal carburizing process. Since the applied hardness unnecessary portion 21 has been decarburized, it is not as hard as the hardness required portion 20.
Thus, according to the carburizing method of the present embodiment, the decarburization step S1 is performed on the local part (hardness unnecessary portion 21) of the workpiece 2, and further the carburizing step S2 is performed on the workpiece 2, thereby A cured portion and an uncured portion can be easily created.
Moreover, in the workpiece 2 in which a portion hardened by the carburizing method according to the present embodiment (hardness required portion 20) and a portion not hardened (hardness unnecessary portion 21) are easily created, Machining such as cutting and polishing of the uncured portion (hardness unnecessary portion 21) becomes easy, and the cost for performing the machining can be reduced.
Moreover, according to the carburizing method in the present embodiment, it is possible to prevent the workpiece 2 from being hardened without carrying out the carburizing treatment on the unnecessary portion 21 of the work 2, thereby reducing the cost for carrying out the carburizing treatment. be able to.

なお、脱炭工程S1で行われるワーク1・2の加熱は、高周波加熱装置で行われることに特に限定するものではなく、レーザ加熱装置、電子ビーム装置、又は、通電加熱装置等によって当該ワーク1・2を加熱しても良いものとする。   The heating of the workpieces 1 and 2 performed in the decarburization step S1 is not particularly limited to being performed by a high-frequency heating device, and the workpiece 1 is heated by a laser heating device, an electron beam device, an electric heating device, or the like. -2 may be heated.

1 ワーク
2 ワーク
10 エッジ部
11 平坦部
20 硬さ必要部
21 硬さ不要部
1 Work 2 Work 10 Edge part 11 Flat part 20 Hardness required part 21 Hardness unnecessary part

Claims (1)

鉄鋼素材からなるワークに炭素を浸透拡散させる、浸炭処理方法であって、
前記ワークにおける任意の一部の箇所に脱炭処理を行って、該任意の一部の箇所に脱炭処理が行われたワークを得る、脱炭工程と、
前記脱炭処理が行われたワークに浸炭処理を行う、浸炭工程と、
を具備する、浸炭処理方法。
A carburizing method in which carbon penetrates and diffuses into a workpiece made of steel,
A decarburization step of performing a decarburization process on an arbitrary part of the workpiece to obtain a workpiece subjected to the decarburization process on the arbitrary part of the workpiece;
Carburizing process for performing a carburizing process on the workpiece subjected to the decarburizing process,
A carburizing method comprising:
JP2009160038A 2009-07-06 2009-07-06 Carburizing method Pending JP2011012335A (en)

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Country Link
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015160982A (en) * 2014-02-27 2015-09-07 新日鐵住金株式会社 Carburized component
CN111020460A (en) * 2019-12-27 2020-04-17 常熟天地煤机装备有限公司 High-nickel carburizing steel and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015160982A (en) * 2014-02-27 2015-09-07 新日鐵住金株式会社 Carburized component
CN111020460A (en) * 2019-12-27 2020-04-17 常熟天地煤机装备有限公司 High-nickel carburizing steel and preparation method thereof

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