JPH06104852B2 - Process for producing carburized steel and articles made therefrom - Google Patents
Process for producing carburized steel and articles made therefromInfo
- Publication number
- JPH06104852B2 JPH06104852B2 JP17973089A JP17973089A JPH06104852B2 JP H06104852 B2 JPH06104852 B2 JP H06104852B2 JP 17973089 A JP17973089 A JP 17973089A JP 17973089 A JP17973089 A JP 17973089A JP H06104852 B2 JPH06104852 B2 JP H06104852B2
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- Prior art keywords
- carburized
- steel
- carburizing
- article
- cold
- 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.)
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Description
【発明の詳細な説明】 （産業上の利用分野） 表面硬化処理としての浸炭は自動車部品を初めとして耐
摩耗性，強靱性を必要とする部品や製品に広く使用され
ている。この発明は低炭素鋼材に熱処理としての浸炭処
理と圧延、引抜き又は鍛造等の塑性加工との複合加工を
施すことにより、有効硬化層の深さ、組織および結晶粒
度等を制御する新規な浸炭鋼の製造法と浸炭鋼を素材と
してこれより品目に応じて成形加工して作られる工具や
自動車部品、その他精密加工部品等の物品に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) Carburizing as a surface hardening treatment is widely used for automobile parts and other parts and products requiring wear resistance and toughness. The present invention is a novel carburized steel for controlling the depth, structure and grain size of an effective hardened layer by subjecting a low carbon steel material to a combination of carburizing treatment as heat treatment and plastic working such as rolling, drawing or forging. The present invention relates to articles such as tools, automobile parts, and other precision processed parts, which are manufactured by carburizing steel as a raw material and are molded and processed according to the item.
（従来の技術） 従来、この種の技術としては低炭素鋼材を物品の用途、
形状および大きさに応じて成形加工した後、物品の耐摩
耗性を向上させるため表面硬化処理することが知られて
いる。また、これを改良したものとして低炭素含有量の
鋼板を所望の厚さまで圧延し、その鋼材に浸炭処理また
は浸炭窒化処理を行なう鋼材の製造法も知られている。
（例えば特開昭51−143519号公報参照） （発明が解決しようとする課題） 前記従来技術で述べたもののうち、前者においては、低
炭素鋼材を成形加工して得られた物品の最終工程として
表面を硬化させる表面硬化法であるため、物品形状が多
様面を有し、しかも数量も多いことから、治具への取り
付け作業に大変な時間と労力を費やしていた。また物品
が油脂で汚れていると浸炭むらを生じるため、浸炭に先
だって有機溶剤で表面脱脂を行なうが、昨今、有機溶剤
としてのフロンガスは大気圏のオゾン層を破壊するなど
地球環境への影響が懸念されるなど大きな社会問題とな
り、今後は有機溶剤の使用禁止が予測されるなどの問題
点を有している。(Prior art) Conventionally, as this kind of technology, low carbon steel materials are used for articles,
It is known to perform a surface hardening treatment in order to improve the wear resistance of the article after the molding processing according to the shape and size. Further, as a modification of this, there is also known a method of manufacturing a steel material in which a steel sheet having a low carbon content is rolled to a desired thickness and the steel material is carburized or carbonitrided.
(See, for example, Japanese Patent Application Laid-Open No. 51-143519) (Problems to be Solved by the Invention) Among those described in the prior art, in the former, as a final step of an article obtained by forming a low carbon steel material Since it is a surface hardening method that hardens the surface, the shape of the article has various surfaces and the quantity is large, so it took a lot of time and effort to attach it to the jig. In addition, if an article is contaminated with oils and fats, uneven carburization occurs, so surface degreasing is performed with an organic solvent prior to carburization.However, recently, CFCs as an organic solvent may affect the global environment, such as destroying the ozone layer in the atmosphere. This is a major social problem, and there are problems such as the prohibition of the use of organic solvents in the future.
後者においては、圧延する段階と浸炭または浸炭窒化処
理する段階があり、この場合、圧延段階を浸炭段階より
も先に行なうので、その後の浸炭または浸炭窒化によっ
て形成される浸炭層は圧延の影響を全く受けないため、
圧延により微細結晶粒が得られず、また圧延により浸炭
表面積の増大をも期待できる、靱性やコスト面で問題が
生じていた。さらに浸炭または浸炭窒化処理に引き続い
て３段階の熱処理と各段階で１〜２回の冷却を行なう必
要があり、特に第３段階の冷却では酸素を含まない媒質
中で行なうなど、製造工程が非常に複雑で高コスト化と
なる問題点を有していた。In the latter case, there is a rolling step and a carburizing or carbonitriding step.In this case, since the rolling step is performed before the carburizing step, the carburized layer formed by the subsequent carburizing or carbonitriding has the effect of rolling. Because I do not receive it at all,
There was a problem in terms of toughness and cost, because fine grains could not be obtained by rolling, and an increase in the carburized surface area could be expected by rolling. Further, it is necessary to carry out a three-step heat treatment and cooling once or twice at each step following the carburizing or carbonitriding treatment. Especially, the third step of cooling is performed in a medium containing no oxygen. In addition, there was a problem that it was complicated and costly.
本発明は、従来技術の有するこのような問題点に鑑みて
なされたものであり、従来技術が成形加工後に浸炭処理
していたものを、浸炭または浸炭窒化などの熱処理を先
に行い、その後圧延，引抜き又は鍛造等の塑性加工を行
なうことで従来困難であった有効硬化層深さ、組織及び
結晶粒等が制御でき、しかも塑性加工による浸炭表面積
の増大に伴う浸炭コストの低減を図る新規なる浸炭鋼の
製造法、並びにこれより作られる物品を提供することを
目的としている。The present invention has been made in view of such problems of the conventional technology, and the conventional technology that was carburized after the forming process is first subjected to heat treatment such as carburizing or carbonitriding, and then rolled. By performing plastic working such as drawing or forging, it is possible to control the effective hardened layer depth, structure and crystal grains, which were difficult in the past, and to reduce the carburizing cost due to the increase of the carburizing surface area by plastic working. It is an object of the present invention to provide a method for manufacturing carburized steel and an article made from the method.
（課題を解決するための手段） 上記の目的を達成するため本発明は、炭素含有量0.35％
以下、アルミニウム含有量0.10％以下の鋼材をガス浸炭
炉でガス浸炭またはガス浸炭窒化処理後浸炭層にパーラ
イト組織を形成するよう空冷し、これにより得られた浸
炭材を熱間または冷間で塑性加工して浸炭表面積を増大
させるとともに、断面形状を丸形、平形、角形または異
形となるよう形成する。そしてガス浸炭またはガス浸炭
窒化処理は、鋼材を適量炉内に定置するか、または浸炭
炉外から炉内へ、そして炉外へと毎分１〜100cmの定速
度で連続的に移動させ、鋼材の表面全体または表面一部
を浸炭処理するようにし、その後、熱間または冷間で塑
性加工するのであるが、熱間では浸炭材を1000〜1250℃
に加熱し浸炭層を有効硬化層深さを冷間よりも５〜35％
増加するようにした後、圧延、引抜き又は鍛造し、冷間
では物品の用途に応じて、事前に浸炭材を球状化焼なま
しを施し、浸炭層の板状セメンタイトを球状セメンタイ
トとして後圧延、引抜きまたは鍛造することで浸炭鋼が
得られる。(Means for Solving the Problems) In order to achieve the above object, the present invention has a carbon content of 0.35%.
Below, steel with an aluminum content of 0.10% or less is air-cooled in a gas carburizing furnace after gas carburizing or gas carbonitriding so as to form a pearlite structure in the carburized layer, and the carburized material obtained by this is hot or cold plastic It is processed to increase the carburizing surface area, and the cross-sectional shape is round, flat, square or irregular. And, gas carburizing or gas carbonitriding is performed by placing the steel material in an appropriate amount in the furnace or continuously moving it from the outside of the carburizing furnace to the inside of the furnace at a constant rate of 1 to 100 cm per minute. The entire surface or a part of the surface is carburized, and then hot or cold plastic working is performed.
Heat the carburized layer to an effective level and harden the layer depth by 5 to 35%
After increasing, after rolling, drawing or forging, according to the use of the article in the cold, subjected to spheroidizing annealing of carburizing material in advance, post-rolling the plate-like cementite of the carburized layer as spherical cementite, Carburized steel can be obtained by drawing or forging.
一方上述の製造法により得られた浸炭鋼を素材としてこ
れより作られる物品の形状や大きさに応じ、切断して成
形加工を行なうことで、繊維状組織による強靱化が図ら
れた物品を得るものである。On the other hand, the carburized steel obtained by the above-mentioned manufacturing method is used as a raw material to cut and form the article according to the shape and size of the article to obtain an article toughened by the fibrous structure. It is a thing.
（作用） 本発明は以上説明したように、従汰技術が鋼材を成形加
工した後、浸炭処理していたものを、本発明では鋼材の
成形加工前に浸炭又は浸炭窒化等の熱処理を行ない、そ
の後で、圧延，引抜きまたは鍛造等の塑性加工を実施す
るものである。(Operation) As described above, according to the present invention, the subordinate technique performs carburizing treatment after the steel material is formed, and in the present invention, the heat treatment such as carburizing or carbonitriding is performed before the steel material is formed, After that, plastic working such as rolling, drawing or forging is performed.
第２図は浸炭表面からの距離と硬さ（HV）との関係を従
来のものと本発明とを比較したものであるが、この図か
ら判るように従来の浸炭は浸炭表面から0.05mmまでに硬
さが低下する現象が見られ、これは異状浸炭組織による
影響である。本発明の浸炭鋼では最表面からの硬さの低
下が見られない理由としては、浸炭後の90％以上の断面
減少率を伴う熱間圧延により、異状浸炭層が極薄化して
硬さ低下がなくなったためで、耐磨耗性に関しては最表
面の硬さが最も大切なので、このことは重要なことであ
る。Fig. 2 compares the relationship between the distance from the carburized surface and the hardness (HV) between the conventional and the present invention. As can be seen from this figure, conventional carburizing up to 0.05 mm from the carburized surface There is a phenomenon that the hardness decreases, which is the effect of the abnormal carburized structure. The reason why the hardness of the carburized steel of the present invention does not decrease from the outermost surface is that the abnormal carburized layer is extremely thinned by the hot rolling accompanied by the cross-sectional reduction rate of 90% or more after carburization and the hardness is decreased. This is important because the hardness of the outermost surface is the most important factor in terms of wear resistance.
また従来の浸炭では浸炭層最表面の炭素温度を0.5％以
下に制御することは浸炭剤のカーボンポテンシャルの関
係から困難であったが、本発明による浸炭鋼の熱間圧延
を例とすると、浸炭剤を1000〜1250℃に高温加熱し、引
続き断面減少率90％まで圧延すれば高温加熱による炭素
拡散と圧延による浸炭層厚さ低減とが連続的に行なわれ
浸炭表面積の増大とともに浸炭層の炭素濃度を0.4〜0.9
％、浸炭有効硬化層深さ0.01〜0.5mmおよび結晶粒度をJ
IS規格での粒度番号５〜10にコントロールでき、この場
合は、浸炭層厚さ0.1mmまで薄くすると、最表面の炭素
濃度を0.5％まで低下することができた。Further, in the conventional carburizing, it was difficult to control the carbon temperature of the outermost surface of the carburized layer to 0.5% or less because of the carbon potential of the carburizing agent, but when the hot rolling of the carburized steel according to the present invention is taken as an example, If the agent is heated to 1000 to 1250 ℃ at high temperature and continuously rolled to a cross-section reduction rate of 90%, carbon diffusion due to high temperature heating and carburized layer thickness reduction due to rolling are continuously performed, and as the carburized surface area increases, carbon in the carburized layer increases. 0.4 to 0.9
%, Carburizing effective hardened layer depth 0.01 to 0.5 mm and grain size J
The grain size can be controlled to 5 to 10 according to the IS standard, and in this case, if the carburized layer thickness was reduced to 0.1 mm, the carbon concentration on the outermost surface could be reduced to 0.5%.
さらに従来法では浸炭層を0.1mm以下の薄さとすると、
浸炭むらが生じるもので薄い浸炭には限度があったが、
本発明では浸炭後塑性加工するので、0.1mm以下の薄さ
でも制御可能となり、歪を嫌う部品などの浸炭法として
応用分野を確立することができる。そしてまた第３図に
示す如く従来法で成形加工後に浸炭して得られる物品
と、本発明による浸炭鋼を素材として成形加工し直接物
品を得るものとの比較図であるが、従来法では鋼材の成
形加工後に900℃付近の高温で長時間浸炭するため、成
形加工時の繊維状組織は消滅しているが本発明は最終的
に成形加工するので、繊維状組織が存在しコーナー部な
どの応力集中部における靱性を高め、さらに同図の如く
浸炭が不必要な箇所を切断面とすれば、一部浸炭層のな
い物品が得られ浸炭層の厚さも成形加工の加工度によっ
て影響されるものである。Furthermore, in the conventional method, if the carburized layer has a thickness of 0.1 mm or less,
There was uneven carburization, and there was a limit to thin carburization,
In the present invention, since plastic working is performed after carburization, control is possible even with a thinness of 0.1 mm or less, and an application field can be established as a carburizing method for parts that do not like strain. FIG. 3 is a comparative view of an article obtained by carburizing after forming by the conventional method as shown in FIG. 3 and a article obtained by directly forming by carburizing the carburized steel according to the present invention as a raw material. Since the carburizing is carried out at a high temperature near 900 ° C for a long time after the molding process, the fibrous structure at the time of the molding process disappears, but since the present invention is finally molded, the fibrous structure is present and the corner portion, etc. If the toughness in the stress concentration part is increased and the cutting surface is a part where carburization is unnecessary as shown in the figure, an article without a carburized layer can be obtained and the thickness of the carburized layer is also affected by the degree of forming process. It is a thing.
（実施例） 実施例について図面を参照して説明する。以上説明した
ように本発明の浸炭鋼を焼入れしたときの硬さ分布は第
２図に示すように最表面の硬さの低下がないことから耐
摩耗性に優れていることが分かる。上述の浸炭鋼による
浸炭ボルト製造法を従来法と比較してみると、従来は第
１図で示すように素材（鋼材）を一定長さに切断後、ヘ
ッダーと転造加工によりボルトに成形後、浸炭または浸
炭窒化処理して浸炭ボルトの製造を行っていた。これに
対し本発明は第１図に示すように浸炭鋼を素材として従
来法と同様に成形加工して浸炭ボルトを製造するもので
あるので、実際には最後の浸炭工程が省略される結果と
なり生産性の向上が期待できる。さらに第３図は鋼材を
成形加工後に高温で浸炭したため繊維状組織が消滅した
従来の浸炭ボルトと、本発明の如く浸炭鋼を成形加工し
た場合に形成される繊維状組織が存在する浸炭ボルトを
示すもので、当然本発明の浸炭ボルトは繊維状組織によ
りコーナー部などの応力集中部における靱性が大きい。
また同図から本発明の浸炭ボルトの端面は切断面に相当
するため、浸炭されていないのも大きな特徴である。(Example) An example will be described with reference to the drawings. As described above, the hardness distribution when quenching the carburized steel of the present invention does not show a decrease in the hardness of the outermost surface as shown in FIG. Comparing the above-mentioned carburized bolt manufacturing method using carburized steel with the conventional method, the conventional method is to cut the material (steel material) into a certain length as shown in Fig. 1 and then form the bolt by the header and rolling process. Carburizing bolts were manufactured by carburizing or carbonitriding. On the other hand, according to the present invention, as shown in FIG. 1, carburized bolts are manufactured by using carburized steel as a raw material in the same manner as in the conventional method, so that the final carburizing step is actually omitted. It can be expected to improve productivity. Further, FIG. 3 shows a conventional carburizing bolt in which the fibrous structure disappears because the steel material is carburized at a high temperature after forming, and a carburizing bolt having a fibrous structure formed when the carburized steel is formed as in the present invention. As shown, the carburized bolt of the present invention naturally has high toughness in stress concentration portions such as corner portions due to the fibrous structure.
Further, from the figure, since the end surface of the carburizing bolt of the present invention corresponds to the cut surface, it is a great feature that it is not carburized.
（発明の効果） 本発明は以上説明したように構成されているので、以下
記述のような効果を奏するものである。(Effects of the Invention) Since the present invention is configured as described above, it has the following effects.
本発明においては従来方法と異なり、浸炭または浸炭窒
化した鋼材を直接熱間または冷間で圧延、引抜きまたは
鍛造等の塑性加工を行なう、いわゆる熱処理による表面
硬化と塑性加工との複合加工を施すことにより、有効硬
化層の深さ、組織及び結晶粒度を制御し得て組織の改
善、浸炭層の改善を可能とし、また部品化、製品化のた
めの成品加工において繊維状組織による強靱化を図る物
品を一貫して製造可能とする画期的製造方法である。In the present invention, unlike the conventional method, a carburized or carbonitrided steel material is directly hot or cold rolled, subjected to plastic working such as drawing or forging, and is subjected to combined working of surface hardening and plastic working by heat treatment. The effective hardened layer depth, structure and grain size can be controlled to improve the structure and the carburized layer, and toughen the fibrous structure in the component processing and product processing for commercialization. It is an epoch-making manufacturing method that enables consistent manufacturing of articles.
第１図は従来法と本発明法の浸炭工程の比較表である。 第２図は従来法と本発明法の浸炭表面からの距離と硬さ
の関係を示すグラフである。 第３図は従来法と本発明法との成形加工後の物品組織の
比較図である。FIG. 1 is a comparison table of the carburizing process of the conventional method and the method of the present invention. FIG. 2 is a graph showing the relationship between the distance from the carburized surface and the hardness of the conventional method and the method of the present invention. FIG. 3 is a comparison diagram of the article structures after the forming process of the conventional method and the method of the present invention.
Claims (4)
量0.1％以下の鋼材をガス浸炭炉でガス浸炭またはガス
浸炭窒化処理後浸炭層にパーライト組織を形成するよう
空冷し、これにより得られた浸炭材を熱間または冷間で
塑性加工して浸炭表面積を増大させるとともに、断面形
状を丸形、平形、角形または異形とすることを特徴とす
る浸炭鋼の製造法。1. A steel material having a carbon content of 0.35% or less and an aluminum content of 0.1% or less is air-cooled in a gas carburizing furnace after gas carburizing or gas carbonitriding so as to form a pearlite structure in the carburized layer. A method for producing carburized steel, characterized in that the carburized material is hot or cold plastically worked to increase the carburized surface area, and the cross-sectional shape is round, flat, square or irregular.
を適量炉内に定置するか、または浸炭炉外から炉内へそ
して炉外へと毎分１〜100cmの定速度で連続的に移動さ
せ、鋼材の表面全体または表面一部を浸炭処理する特許
請求の範囲第１項記載の浸炭鋼の製造法。2. In the gas carburizing or gas carbonitriding treatment, an appropriate amount of steel is placed in the furnace or continuously moved from outside the carburizing furnace to inside the furnace at a constant speed of 1 to 100 cm per minute. The method for producing carburized steel according to claim 1, wherein the entire surface or a part of the surface of the steel material is carburized.
では浸炭材を1000〜1250℃に加熱し浸炭層の有効硬化層
深さを冷間よりも５〜35％増加するようにした後、圧
延、引抜きまたは鍛造し、冷間では物品の用途に応じて
事前に浸炭材を球状化焼きなましを施し、浸炭層の板状
セメンタイトを球状セメンタイトとした後圧延、引抜き
又は鍛造する特許請求の範囲第１項記載の浸炭鋼の製造
法。3. In the case of hot or cold plastic working, the carburized material is heated to 1000 to 1250 ° C. during hot working so that the effective hardened layer depth of the carburized layer is increased by 5 to 35% as compared with cold working. After that, it is rolled, drawn or forged, and in the cold, the carburized material is spheroidized and annealed in advance according to the use of the article, and the plate-like cementite of the carburized layer is made into spherical cementite, and then rolled, drawn or forged. The method for producing carburized steel according to item 1 above.
項のいずれかによって製造された浸炭鋼を素材として、
これにより作られる物品の形状や大きさに応じ、切断し
て成形加工を行なうことで、繊維状組織による強靱化が
図られることを特徴とする物品。4. Claims 1, 2 or 3
Using carburized steel manufactured by any of the items,
An article characterized by being toughened by a fibrous structure by cutting and forming according to the shape and size of the article thus produced.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17973089A JPH06104852B2 (en) | 1989-07-11 | 1989-07-11 | Process for producing carburized steel and articles made therefrom |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17973089A JPH06104852B2 (en) | 1989-07-11 | 1989-07-11 | Process for producing carburized steel and articles made therefrom |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0344414A JPH0344414A (en) | 1991-02-26 |
| JPH06104852B2 true JPH06104852B2 (en) | 1994-12-21 |
Family
ID=16070867
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17973089A Expired - Fee Related JPH06104852B2 (en) | 1989-07-11 | 1989-07-11 | Process for producing carburized steel and articles made therefrom |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06104852B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6942739B2 (en) * | 2001-10-26 | 2005-09-13 | Exxonmobil Research And Engineering Company | Reactive heat treatment to form pearlite from an iron containing article |
| JP7356036B2 (en) * | 2020-03-26 | 2023-10-04 | 日本製鉄株式会社 | Forging materials, forged parts, and methods for producing forged parts |
| JP7356035B2 (en) * | 2020-03-26 | 2023-10-04 | 日本製鉄株式会社 | Forging materials, forged parts and manufacturing methods thereof |
-
1989
- 1989-07-11 JP JP17973089A patent/JPH06104852B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0344414A (en) | 1991-02-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |