JPH05125439A - Manufacture of non-heat-treated steel parts having high yield ratio - Google Patents
Manufacture of non-heat-treated steel parts having high yield ratioInfo
- Publication number
- JPH05125439A JPH05125439A JP31329891A JP31329891A JPH05125439A JP H05125439 A JPH05125439 A JP H05125439A JP 31329891 A JP31329891 A JP 31329891A JP 31329891 A JP31329891 A JP 31329891A JP H05125439 A JPH05125439 A JP H05125439A
- Authority
- JP
- Japan
- Prior art keywords
- yield ratio
- steel
- treated steel
- high yield
- heat
- 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.)
- Pending
Links
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は構造用部品の製造にお
いて焼入れ焼き戻しをせずに降伏比の高い部品を製造す
る方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high yield ratio component without quenching and tempering in the production of a structural component.
【０００２】[0002]
【従来技術】多種の構造用部品においては鍛造加工後
に、焼入れ焼戻し等の調質処理を施し、目的及び用途に
応じて必要な強度及び靱性に調質して使用されていた
が、この場合、調質処理に多大の熱エネルギーを要する
ことから、調質処理がコスト高となって製造コストが高
くつく。そのため、省エネルギー及び低コスト化の観点
から調質処理を省略することができるようにした非調質
鋼が開発され、構造用部品に既に実用化されている。2. Description of the Related Art In various structural parts, after forging, a tempering treatment such as quenching and tempering is performed to adjust the strength and toughness required according to the purpose and application. Since a large amount of heat energy is required for the refining treatment, the refining treatment is expensive and the manufacturing cost is high. Therefore, from the viewpoint of energy saving and cost reduction, a non-heat treated steel has been developed which can be subjected to the heat treatment and has already been put into practical use for structural parts.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
非調質鋼による部品では、抗張力については８０ｋｇｆ
／ｍｍ2 以上の値が比較的容易に得られるものの、降伏
比（０．２％耐力／抗張力）が調質部品に比較して不足
するという問題があった。この発明は、かかる問題点に
鑑み、８０ｋｇｆ／ｍｍ2 以上の強度を有するにもかか
わらず優れた降伏比を有する鋼部品を非調質で製造する
方法を提供することを課題とする。However, the conventional non-heat treated steel parts have a tensile strength of 80 kgf.
Although a value of / mm 2 or more can be obtained relatively easily, there is a problem that the yield ratio (0.2% proof stress / tensile strength) is insufficient as compared with the heat-treated parts. In view of the above problems, it is an object of the present invention to provide a method for producing a steel part having a strength of 80 kgf / mm 2 or more and having an excellent yield ratio without heat treatment.
【０００４】[0004]
【課題を解決するための手段】そして本件発明者らは、
熱間鍛造後室温まで冷却した後、所定の温度（３５０℃
〜Ａｃ1 ）、時間（０．５〜１０時間）に再加熱するこ
とにより、高い降伏比を有する鋼部品が得られることを
知見し、本願発明を完成したものである。[Means for Solving the Problems] The present inventors
After hot forging and cooling to room temperature, the specified temperature (350 ℃
To Ac 1), by re-heating time (0.5 to 10 hours), and found that the steel part is obtained with a high yield ratio, and completed the present invention.
【０００５】即ち、本願の第１の発明に係る非調質鋼部
品の製造方法は、重量比で、 Ｃ ：０．２〜０．５％、 Ｓｉ：０．０５〜１．０％、 Ｍｎ：０．５〜２．５％、 Ｖ ：０．０５〜０．５％、 Ｃｒ：０．２〜１．０％、 Ａｌ：０．０１〜０．１％、 Ｓ ：０．０２〜０．３％、 Ｐｂ：０．０２〜０．３％ を含有し、残部がＦｅ及び不純物元素からなる素材鋼を
熱間鍛造後常温まで冷却した後、３５０℃〜Ａｃ1 に再
加熱し、０．５〜１０時間保持後空冷することを特徴と
する降伏比の高い非調質鋼部品の製造方法であり、ま
た、本願の第２の発明に係る非調質鋼部品の製造方法
は、重量比で、 Ｃ ：０．２〜０．５％、 Ｓｉ：０．０５〜１．０％、 Ｍｎ：０．５〜２．５％、 Ｖ ：０．０５〜０．５％、 Ｃｒ：０．２〜１．０％、 Ａｌ：０．０１〜０．１％、 Ｓ ：０．０２〜０．３％、 Ｐｂ：０．０２〜０．３％ を含有し、更に Ｎｂ：０．１％以下、 Ｔｉ：０．１％以下 のうち１種または２種を含有し、残部がＦｅ及び不純物
元素からなる素材鋼を熱間鍛造後常温まで冷却した後、
３５０℃〜Ａｃ1 に再加熱し、０．５〜１０時間保持後
空冷することを特徴とする降伏比の高い非調質鋼部品の
製造方法である。That is, in the method for producing a non-heat treated steel part according to the first invention of the present application, C: 0.2 to 0.5%, Si: 0.05 to 1.0%, Mn by weight ratio. : 0.5-2.5%, V: 0.05-0.5%, Cr: 0.2-1.0%, Al: 0.01-0.1%, S: 0.02-0 3%, Pb: 0.02 to 0.3%, and the rest is Fe and impurity elements, the material steel is hot forged and then cooled to room temperature, and then reheated to 350 ° C. to Ac 1 , and 0 A method for manufacturing a non-heat treated steel part having a high yield ratio, characterized by holding for 5 to 10 hours and then air cooling, and a method for manufacturing a non-heat treated steel part according to the second invention of the present application, By ratio, C: 0.2-0.5%, Si: 0.05-1.0%, Mn: 0.5-2.5%, V: 0.05-0.5%, Cr: 0. .2 to 1.0%, Al : 0.01 to 0.1%, S: 0.02 to 0.3%, Pb: 0.02 to 0.3%, further Nb: 0.1% or less, Ti: 0.1% After hot forging a material steel containing one or two of the following, with the balance being Fe and impurity elements, and cooling to room temperature,
It is a method for producing a non-heat treated steel part having a high yield ratio, which comprises reheating to 350 ° C. to Ac 1 and holding for 0.5 to 10 hours and then air cooling.
【０００６】[0006]
【作用】以下、本発明において各成分及び再加熱条件を
前記の通りに限定した理由を説明する。 〔Ｃ：０．２〜０．５％〕Ｃは鋼の強度を高めるために
有効であり、調質せずに８０ｋｇｆ／ｍｍ2 以上出させ
るには０．２％以上添加する必要がある。しかし、０．
５％を越えると靱性を低下させるため、上限を０．５％
とする。 〔Ｓｉ：０．０５〜１．０％〕Ｓｉは溶製時の脱酸剤と
して加えられる外、強度確保のため０．０５％以上添加
する必要がある。しかし、１．０％を越えると靱性を低
下させるため、上限を１．０％とする。 〔Ｍｎ：０．５〜２．５％〕ＭｎはＳｉと同様、溶製時
の脱酸剤として加えられる外、強度および靱性の向上に
有効な元素であり、他の合金元素との相関を考慮して、
０．５％以上添加する必要がある。しかし、Ｍｎは他方
で被削性を低下させるため上限を２．５％とする。 〔Ｖ：０．０５〜０．５％〕Ｖは熱間鍛造のまま、即ち
調質しない場合に、強度、靱性を確保するため重要な元
素であり、その効果は０．０５％以上で顕著になる。し
かし、０．５％を越えると効果が飽和するので上限を
０．５％とする。 〔Ｃｒ：０．２〜１．０％〕Ｃｒは熱間鍛造のままでの
強度、靱性を確保するためにＶと共に有効な元素であ
り、０．２％以上で顕著になる。しかし、１．０％を越
えると靱性を低下させるので上限を１．０％とする。 〔Ａｌ：０．０１〜０．１％〕Ａｌ脱酸剤とした加えら
れる他、結晶粒微細化にも有効であるが、０．０１％以
下ではその効果は小さい。また、０．１％を越えると被
削性を低下させるので上限を０．１％以下とする。 〔Ｓ：０．０２〜０．３％〕本発明において、被削性を
向上させるためには少なくとも０．０２％以上添加する
必要がある。しかし、０．３％を越えると熱間加工性が
劣化し、製造上の問題が発生すると共に靱性も低下する
ため上限を０．３％以下とする。 〔Ｐｂ：０．０２〜０．３％〕ＰｂはＳと同様、被削性
を向上させるために有効な元素であり、０．０２％以上
でその効果が現れる。しかし、０．３％を越えると熱間
加工性を低下させるので上限を０．３％とする。 〔Ｎｂ：０．１％以下、Ｔｉ：０．１％以下〕本願の第
２の発明鋼は、第１の発明鋼に更にＮｂ及び／又はＴｉ
を添加したもので、結晶粒度を微細にし、靱性を向上さ
せ、特に大きな靱性が必要な部品に用いる目的で完成さ
せたものである。しかし、Ｎｂ及びＴｉともに０．１％
を越えて添加をしても効果は増大しないため上限は０．
１％以下とする。The function of each component and the reheating conditions in the present invention will be described below. [C: 0.2 to 0.5%] C is effective for increasing the strength of steel, and it is necessary to add 0.2% or more to obtain 80 kgf / mm 2 or more without tempering. However, 0.
If it exceeds 5%, the toughness decreases, so the upper limit is 0.5%.
And [Si: 0.05 to 1.0%] In addition to being added as a deoxidizer during melting, Si must be added in an amount of 0.05% or more to secure the strength. However, if it exceeds 1.0%, the toughness decreases, so the upper limit is made 1.0%. [Mn: 0.5 to 2.5%] Like Si, Mn is an element effective in improving strength and toughness as well as being added as a deoxidizer during melting, and has a correlation with other alloy elements. In consideration of,
It is necessary to add 0.5% or more. However, Mn lowers the machinability on the other hand, so the upper limit is made 2.5%. [V: 0.05 to 0.5%] V is an important element for ensuring strength and toughness when hot forging is performed, that is, when heat treatment is not performed, and its effect is remarkable at 0.05% or more. become. However, if it exceeds 0.5%, the effect is saturated, so the upper limit is made 0.5%. [Cr: 0.2 to 1.0%] Cr is an element that is effective together with V in order to secure the strength and toughness in the as-hot-forged state, and it becomes remarkable at 0.2% or more. However, if it exceeds 1.0%, the toughness decreases, so the upper limit is made 1.0%. [Al: 0.01 to 0.1%] Besides being added as an Al deoxidizer, it is also effective for refining crystal grains, but if it is 0.01% or less, the effect is small. Further, if over 0.1%, the machinability deteriorates, so the upper limit is made 0.1% or less. [S: 0.02 to 0.3%] In the present invention, it is necessary to add at least 0.02% or more in order to improve machinability. However, if it exceeds 0.3%, the hot workability deteriorates, problems in production occur, and the toughness also decreases, so the upper limit is made 0.3% or less. [Pb: 0.02 to 0.3%] Like S, Pb is an element effective for improving machinability, and its effect is exhibited at 0.02% or more. However, if it exceeds 0.3%, the hot workability is deteriorated, so the upper limit is made 0.3%. [Nb: 0.1% or less, Ti: 0.1% or less] In the second invention steel of the present application, Nb and / or Ti is further added to the first invention steel.
Was added to improve the toughness, and was completed for the purpose of being used for parts requiring particularly high toughness. However, both Nb and Ti are 0.1%
The effect does not increase even if it is added in excess of 0.1, so the upper limit is 0.
1% or less.
【０００７】〔再加熱条件〕本発明において再加熱条件
を（３５０℃〜Ａｃ1 ）×（０．５〜１０時間）とした
のは以下の理由による。まず、処理温度としては析出物
を生成させる温度として、最低３５０℃必要である。ま
た、上限としてはフェライト領域の上限であるフェライ
ト・オーステナイト変態点（Ａｃ1 ）以下とする。次に
処理温度としては析出物を生成させる時間として、最低
０．５時間必要である。しかし、１０時間以上の保持
は、析出物が増加し、転位の運動に対して障害物となる
ため降伏強さが著しく大きくなる反面、非常に脆い合金
となる。従って、保持時間は０．５〜１０時間とする。[Reheating Condition] In the present invention, the reheating condition is (350 ° C. to Ac 1 ) × (0.5 to 10 hours) for the following reason. First, as the processing temperature, at least 350 ° C. is required as the temperature for forming the precipitate. The upper limit is set to the ferrite-austenite transformation point (Ac 1 ) which is the upper limit of the ferrite region. Next, as the processing temperature, at least 0.5 hour is required as the time for forming a precipitate. However, holding for 10 hours or more increases precipitates and becomes an obstacle to the movement of dislocations, so that the yield strength remarkably increases, but on the other hand, the alloy becomes extremely brittle. Therefore, the holding time is 0.5 to 10 hours.
【０００８】[0008]
【実施例】表１に示す成分を有する鋼を１００ｋｇ真空
溶解炉を用いて溶製した。１００ｋｇの鋼塊は１２００
℃で鍛造して棒鋼に鍛伸した。その後本件に関わる時効
により所定の温度、時間で熱処理し、これを用いて引張
試験片を作製し試験を行った。ここで表１に各供試材の
化学成分を、表２に試験結果を示す。比較鋼Ａ、Ｅ、Ｈ
については、鋼番１、２、３の化学成分を有するが従来
の方法で製造した非調質鋼である。EXAMPLES Steel having the components shown in Table 1 was melted using a 100 kg vacuum melting furnace. 1200 for a 100 kg steel ingot
Forged at ℃, forged into steel bars. After that, heat treatment was performed at a predetermined temperature and time by aging related to the present case, and using this, a tensile test piece was prepared and tested. Here, Table 1 shows the chemical composition of each test material, and Table 2 shows the test results. Comparative steels A, E, H
No. 6 is a non-heat treated steel that has the chemical composition of steel Nos. 1, 2, and 3 but is manufactured by the conventional method.
【０００９】[0009]
【表１】 [Table 1]
【００１０】[0010]
【表２】 [Table 2]
【００１１】試験結果によれば、従来の方法および本発
明の再加熱条件を外れた方法により製造した非調質鋼
Ａ、Ｅ、Ｈ、Ｑ、Ｒ、Ｓについてはいずれも降伏比０．
８に満たない。これに対して発明鋼Ｂ〜Ｄ、Ｆ、Ｇ、Ｉ
〜Ｐ、Ｔ〜Ｕではいずれも降伏比０．８以上を有する。
なお、その他の機械的性質や被削性その他の特性も充分
に満足すべきものであった。According to the test results, the yield ratios of all the non-heat treated steels A, E, H, Q, R and S produced by the conventional method and the method of the present invention which deviates from the reheating conditions are 0.
Less than 8 On the other hand, invention steels B to D, F, G, I
-P and T-U have a yield ratio of 0.8 or more.
Other mechanical properties, machinability, and other properties were also satisfactory.
【００１２】[0012]
【発明の効果】以上のように、本発明によれば、熱間加
工後室温まで冷却した後、更に所定の温度、時間に加熱
することにより優れた降伏比を有する鋼が得られること
から、本来、調質でしか得られないような高い降伏比が
必要な機械部品を非調質で製造できるようになった。As described above, according to the present invention, a steel having an excellent yield ratio can be obtained by heating after hot working to room temperature and then heating at a predetermined temperature and time. Originally, it became possible to manufacture mechanical parts that require a high yield ratio that can only be obtained by tempering without tempering.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成４年２月２７日[Submission date] February 27, 1992
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】全文[Name of item to be corrected] Full text
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【書類名】 明細書[Document name] Statement
【発明の名称】 高降伏比を有する非調質鋼部品の製造
方法Title: Method for manufacturing non-heat treated steel parts having high yield ratio
【特許請求の範囲】[Claims]
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】この発明は構造用部品の製造にお
いて焼入れ焼き戻しをせずに降伏比の高い部品を製造す
る方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high yield ratio component without quenching and tempering in the production of a structural component.
【０００２】[0002]
【従来技術】多種の構造用部品においては鍛造加工後
に、焼入れ焼戻し等の調質処理を施し、目的及び用途に
応じて必要な強度及び靱性に調質して使用されていた
が、この場合、調質処理に多大の熱エネルギーを要する
ことから、調質処理がコスト高となって製造コストが高
くつく。そのため、省エネルギー及び低コスト化の観点
から調質処理を省略することができるようにした非調質
鋼が開発され、構造用部品に既に実用化されている。2. Description of the Related Art In various structural parts, after forging, a tempering treatment such as quenching and tempering is performed to adjust the strength and toughness required according to the purpose and application. Since a large amount of heat energy is required for the refining treatment, the refining treatment is expensive and the manufacturing cost is high. Therefore, from the viewpoint of energy saving and cost reduction, a non-heat treated steel has been developed which can be subjected to the heat treatment and has already been put into practical use for structural parts.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
非調質鋼による部品では、抗張力については８０ｋｇｆ
／ｍｍ2 以上の値が比較的容易に得られるものの、降伏
比（０．２％耐力／抗張力）が調質部品に比較して不足
するという問題があった。この発明は、かかる問題点に
鑑み、８０ｋｇｆ／ｍｍ2 以上の強度を有するにもかか
わらず優れた降伏比を有する鋼部品を非調質で製造する
方法を提供することを課題とする。However, the conventional non-heat treated steel parts have a tensile strength of 80 kgf.
Although a value of / mm 2 or more can be obtained relatively easily, there is a problem that the yield ratio (0.2% proof stress / tensile strength) is insufficient as compared with the heat-treated parts. In view of the above problems, it is an object of the present invention to provide a method for producing a steel part having a strength of 80 kgf / mm 2 or more and having an excellent yield ratio without heat treatment.
【０００４】[0004]
【課題を解決するための手段】そして本件発明者らは、
熱間鍛造後室温まで冷却した後、所定の温度（３５０℃
〜Ａｃ1 ）、時間（０．５〜１０時間）に再加熱するこ
とにより、高い降伏比を有する鋼部品が得られることを
知見し、本願発明を完成したものである。[Means for Solving the Problems] The present inventors
After hot forging and cooling to room temperature, the specified temperature (350 ℃
To Ac 1), by re-heating time (0.5 to 10 hours), and found that the steel part is obtained with a high yield ratio, and completed the present invention.
【０００５】即ち、本願の第１の発明に係る非調質鋼部
品の製造方法は、重量比で、 Ｃ ：０．２〜０．５％、 Ｓｉ：０．０５〜０．８０％未満、 Ｍｎ：０．５〜２．５％、 Ｖ ：０．０５〜０．５％、 Ｃｒ：０．２〜１．０％、 Ａｌ：０．０１〜０．１％、 Ｓ ：０．０２〜０．３％、 Ｐｂ：０．０２〜０．３％ を含有し、残部がＦｅ及び不純物元素からなる素材鋼を
熱間鍛造後常温まで冷却した後、３５０℃〜Ａｃ1 に再
加熱し、０．５〜１０時間保持後空冷することを特徴と
する降伏比の高い非調質鋼部品の製造方法であり、ま
た、本願の第２の発明に係る非調質鋼部品の製造方法
は、重量比で、 Ｃ ：０．２〜０．５％、 Ｓｉ：０．０５〜０．８０％未満、 Ｍｎ：０．５〜２．５％、 Ｖ ：０．０５〜０．５％、 Ｃｒ：０．２〜１．０％、 Ａｌ：０．０１〜０．１％、 Ｓ ：０．０２〜０．３％、 Ｐｂ：０．０２〜０．３％ を含有し、更に Ｎｂ：０．１％以下、 Ｔｉ：０．１％以下 のうち１種または２種を含有し、残部がＦｅ及び不純物
元素からなる素材鋼を熱間鍛造後常温まで冷却した後、
３５０℃〜Ａｃ1 に再加熱し、０．５〜１０時間保持後
空冷することを特徴とする降伏比の高い非調質鋼部品の
製造方法である。That is, in the method for manufacturing a non-heat treated steel part according to the first invention of the present application, C: 0.2 to 0.5%, Si: 0.05 to less than 0.80% by weight, Mn: 0.5-2.5%, V: 0.05-0.5%, Cr: 0.2-1.0%, Al: 0.01-0.1%, S: 0.02- 0.3%, Pb: 0.02 to 0.3%, with the balance being Fe and impurity elements, the material steel was hot forged, cooled to room temperature, and then reheated to 350 ° C to Ac 1 . A method for manufacturing a non-heat treated steel part having a high yield ratio, which is characterized by holding for 0.5 to 10 hours and then air cooling, and a method for manufacturing a non-heat treated steel part according to the second invention of the present application, By weight ratio, C: 0.2 to 0.5%, Si: 0.05 to less than 0.80% , Mn: 0.5 to 2.5%, V: 0.05 to 0.5%, Cr : 0.2 ~ 0.0%, Al: 0.01 to 0.1%, S: 0.02 to 0.3%, Pb: 0.02 to 0.3%, and Nb: 0.1% or less, Ti : 0.1% or less, one or two of which are contained, and the balance being Fe and impurity elements
It is a method for producing a non-heat treated steel part having a high yield ratio, which comprises reheating to 350 ° C. to Ac 1 and holding for 0.5 to 10 hours and then air cooling.
【０００６】[0006]
【作用】以下、本発明において各成分及び再加熱条件を
前記の通りに限定した理由を説明する。 〔Ｃ：０．２〜０．５％〕Ｃは鋼の強度を高めるために
有効であり、調質せずに８０ｋｇｆ／ｍｍ2 以上出させ
るには０．２％以上添加する必要がある。しかし、０．
５％を越えると靱性を低下させるため、上限を０．５％
とする。 〔Ｓｉ：０．０５〜０．８０％未満〕Ｓｉは溶製時の脱
酸剤として加えられる外、強度確保のため０．０５％以
上添加する必要がある。しかし、０．８０％を越えると
靱性を低下させるため、上限を０．８０％未満とする。 〔Ｍｎ：０．５〜２．５％〕ＭｎはＳｉと同様、溶製時
の脱酸剤として加えられる外、強度および靱性の向上に
有効な元素であり、他の合金元素との相関を考慮して、
０．５％以上添加する必要がある。しかし、Ｍｎは他方
で被削性を低下させるため上限を２．５％とする。 〔Ｖ：０．０５〜０．５％〕Ｖは熱間鍛造のまま、即ち
調質しない場合に、強度、靱性を確保するため重要な元
素であり、その効果は０．０５％以上で顕著になる。し
かし、０．５％を越えると効果が飽和するので上限を
０．５％とする。 〔Ｃｒ：０．２〜１．０％〕Ｃｒは熱間鍛造のままでの
強度、靱性を確保するためにＶと共に有効な元素であ
り、０．２％以上で顕著になる。しかし、１．０％を越
えると靱性を低下させるので上限を１．０％とする。 〔Ａｌ：０．０１〜０．１％〕Ａｌ脱酸剤とした加えら
れる他、結晶粒微細化にも有効であるが、０．０１％以
下ではその効果は小さい。また、０．１％を越えると被
削性を低下させるので上限を０．１％以下とする。 〔Ｓ：０．０２〜０．３％〕本発明において、被削性を
向上させるためには少なくとも０．０２％以上添加する
必要がある。しかし、０．３％を越えると熱間加工性が
劣化し、製造上の問題が発生すると共に靱性も低下する
ため上限を０．３％以下とする。 〔Ｐｂ：０．０２〜０．３％〕ＰｂはＳと同様、被削性
を向上させるために有効な元素であり、０．０２％以上
でその効果が現れる。しかし、０．３％を越えると熱間
加工性を低下させるので上限を０．３％とする。 〔Ｎｂ：０．１％以下、Ｔｉ：０．１％以下〕本願の第
２の発明鋼は、第１の発明鋼に更にＮｂ及び／又はＴｉ
を添加したもので、結晶粒度を微細にし、靱性を向上さ
せ、特に大きな靱性が必要な部品に用いる目的で完成さ
せたものである。しかし、Ｎｂ及びＴｉともに０．１％
を越えて添加をしても効果は増大しないため上限は０．
１％以下とする。The function of each component and the reheating conditions in the present invention will be described below. [C: 0.2 to 0.5%] C is effective for increasing the strength of steel, and it is necessary to add 0.2% or more to obtain 80 kgf / mm 2 or more without tempering. However, 0.
If it exceeds 5%, the toughness decreases, so the upper limit is 0.5%.
And [Si: 0.05 to less than 0.80% ] In addition to being added as a deoxidizer during melting, Si must be added in an amount of 0.05% or more to secure strength. However, if it exceeds 0.80% , the toughness decreases, so the upper limit is made less than 0.80% . [Mn: 0.5 to 2.5%] Like Si, Mn is an element effective in improving strength and toughness as well as being added as a deoxidizer during melting, and has a correlation with other alloy elements. In consideration of,
It is necessary to add 0.5% or more. However, Mn lowers the machinability on the other hand, so the upper limit is made 2.5%. [V: 0.05 to 0.5%] V is an important element for ensuring strength and toughness when hot forging is performed, that is, when heat treatment is not performed, and its effect is remarkable at 0.05% or more. become. However, if it exceeds 0.5%, the effect is saturated, so the upper limit is made 0.5%. [Cr: 0.2 to 1.0%] Cr is an element that is effective together with V in order to secure the strength and toughness in the as-hot-forged state, and it becomes remarkable at 0.2% or more. However, if it exceeds 1.0%, the toughness decreases, so the upper limit is made 1.0%. [Al: 0.01 to 0.1%] Besides being added as an Al deoxidizer, it is also effective for refining crystal grains, but if it is 0.01% or less, the effect is small. Further, if over 0.1%, the machinability deteriorates, so the upper limit is made 0.1% or less. [S: 0.02 to 0.3%] In the present invention, it is necessary to add at least 0.02% or more in order to improve machinability. However, if it exceeds 0.3%, the hot workability deteriorates, problems in production occur, and the toughness also decreases, so the upper limit is made 0.3% or less. [Pb: 0.02 to 0.3%] Like S, Pb is an element effective for improving machinability, and its effect is exhibited at 0.02% or more. However, if it exceeds 0.3%, the hot workability is deteriorated, so the upper limit is made 0.3%. [Nb: 0.1% or less, Ti: 0.1% or less] In the second invention steel of the present application, Nb and / or Ti is further added to the first invention steel.
Was added to improve the toughness, and was completed for the purpose of being used for parts requiring particularly high toughness. However, both Nb and Ti are 0.1%
The effect does not increase even if it is added in excess of 0.1, so the upper limit is 0.
1% or less.
【０００７】本発明において、高い降伏比が得られる理
由は、鍛造後冷却した部品を再加熱することでＶ、Ｃ
ｒ、Ｎｂ、Ｔｉ等の炭窒化物が析出し、また残留オース
テナイトも分解しこの時にも炭窒化物が析出することな
どにより、結晶辷り（転移）が起こりにくくなることが
主原因と考えられる。本発明において再加熱条件を（３
５０℃〜Ａｃ1 ）×（０．５〜１０時間）と規制した
が、その理由は次のとおりである。まず、処理温度とし
ては、上記析出物を生成させる温度として最低３５０℃
必要である。上限はフェライト領域の上限、即ちフェラ
イト・オーステナイト変態点（Ａｃ1 ）まで有効であ
る。次に処理温度は、必要析出物を得るには、温度が高
い場合で０．５時間、温度が低い場合最長１０時間を必
要とする。 In the present invention, the reason why a high yield ratio is obtained.
The reason is V, C by reheating the cooled parts after forging.
Carbonitrides such as r, Nb, and Ti are deposited and residual aus
The tenite also decomposes and carbonitride does not precipitate at this time.
Depending on the condition, crystal crawl (transition) is less likely to occur.
Probably the main cause. In the present invention, the reheating condition is (3
50 ° C. to Ac 1) was restricted with × (0.5 to 10 hours)
However, the reason is as follows . First, the treatment temperature, minimum 350 ° C. as the temperature for generating the precipitate
It is necessary . The upper limit is the upper limit of the ferrite region, i.e. effective der to Blow <br/> site-austenite transformation point (Ac 1)
It Next, the processing temperature is high to obtain the required precipitate.
0.5 hours when the temperature is low and 10 hours when the temperature is low.
I need it.
【０００８】[0008]
【実施例】表１に示す成分を有する鋼を１００ｋｇ真空
溶解炉を用いて溶製した。１００ｋｇの鋼塊は１２００
℃で鍛造して棒鋼に鍛伸した。その後本件に関わる時効
により所定の温度、時間で熱処理し、これを用いて引張
試験片を作製し試験を行った。ここで表１に各供試材の
化学成分を、表２に試験結果を示す。比較鋼Ａ、Ｅ、Ｈ
については、鋼番１、２、３の化学成分を有するが従来
の方法で製造した非調質鋼である。EXAMPLES Steel having the components shown in Table 1 was melted using a 100 kg vacuum melting furnace. 1200 for a 100 kg steel ingot
Forged at ℃, forged into steel bars. After that, heat treatment was performed at a predetermined temperature and time by aging related to the present case, and using this, a tensile test piece was prepared and tested. Here, Table 1 shows the chemical composition of each test material, and Table 2 shows the test results. Comparative steels A, E, H
No. 6 is a non-heat treated steel that has the chemical composition of steel Nos. 1, 2, and 3 but is manufactured by the conventional method.
【０００９】[0009]
【表１】 [Table 1]
【００１０】[0010]
【表２】 [Table 2]
【００１１】試験結果によれば、従来の方法および本発
明の再加熱条件を外れた方法により製造した非調質鋼
Ａ、Ｅ、Ｈ、Ｑ、Ｒについてはいずれも降伏比０．８に
満たない。これに対して発明鋼Ｂ〜Ｄ、Ｆ、Ｇ、Ｉ〜
Ｐ、Ｓ〜Ｕではいずれも降伏比０．８以上を有する。な
お、その他の機械的性質や被削性その他の特性も充分に
満足すべきものであった。According to the test result, conventional methods and non-heat treated steel A was prepared by methods outside the reheating conditions of the present invention, E, H, Q, none For the R satisfy the yield ratio 0.8 Absent. On the other hand, invention steels B to D, F, G, I to
Each of P and S to U has a yield ratio of 0.8 or more. Other mechanical properties, machinability, and other properties were also satisfactory.
【００１２】[0012]
【発明の効果】以上のように、本発明によれば、熱間加
工後室温まで冷却した後、更に所定の温度、時間に加熱
することにより優れた降伏比を有する鋼が得られること
から、本来、調質でしか得られないような高い降伏比が
必要な機械部品を非調質で製造できるようになった。As described above, according to the present invention, a steel having an excellent yield ratio can be obtained by heating after hot working to room temperature and then heating at a predetermined temperature and time. Originally, it became possible to manufacture mechanical parts that require a high yield ratio that can only be obtained by tempering without tempering.
Claims (2)
を熱間鍛造後常温まで冷却した後、３５０°Ｃ〜Ａｃ1
に再加熱し、０．５〜１０時間保持後空冷することを特
徴とする降伏比の高い非調質鋼部品の製造方法。1. By weight ratio, C: 0.2-0.5%, Si: 0.05-1.0%, Mn: 0.5-2.5%, V: 0.05-0. 5%, Cr: 0.2 to 1.0%, Al: 0.01 to 0.1%, S: 0.02 to 0.3%, Pb: 0.02 to 0.3%, After hot forging the raw material steel with the balance being Fe and impurity elements, after cooling to room temperature, 350 ° C to Ac 1
A method for manufacturing a non-heat treated steel part having a high yield ratio, which comprises reheating the steel sheet, holding it for 0.5 to 10 hours, and then air cooling.
元素からなる素材鋼を熱間鍛造後常温まで冷却した後、
３５０°Ｃ〜Ａｃ1 に再加熱し、０．５〜１０時間保持
後空冷することを特徴とする降伏比の高い非調質鋼部品
の製造方法。2. By weight ratio, C: 0.2-0.5%, Si: 0.05-1.0%, Mn: 0.5-2.5%, V: 0.05-0. 5%, Cr: 0.2 to 1.0%, Al: 0.01 to 0.1%, S: 0.02 to 0.3%, Pb: 0.02 to 0.3%, Further, after the material steel containing one or two of Nb: 0.1% or less and Ti: 0.1% or less, and the balance of Fe and impurity elements, is cooled to room temperature after hot forging,
A method for producing a non-heat treated steel part having a high yield ratio, which comprises reheating to 350 ° C to Ac 1 , holding for 0.5 to 10 hours, and then air cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31329891A JPH05125439A (en) | 1991-10-31 | 1991-10-31 | Manufacture of non-heat-treated steel parts having high yield ratio |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31329891A JPH05125439A (en) | 1991-10-31 | 1991-10-31 | Manufacture of non-heat-treated steel parts having high yield ratio |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05125439A true JPH05125439A (en) | 1993-05-21 |
Family
ID=18039542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31329891A Pending JPH05125439A (en) | 1991-10-31 | 1991-10-31 | Manufacture of non-heat-treated steel parts having high yield ratio |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05125439A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0709223A1 (en) | 1994-10-27 | 1996-05-01 | Canon Kabushiki Kaisha | Recording medium, and image forming method and printed material making use of the same |
| US5804320A (en) * | 1994-10-31 | 1998-09-08 | Canon Kabushiki Kaisha | Recording medium |
| US5965252A (en) * | 1995-05-01 | 1999-10-12 | Canon Kabushiki Kaisha | Printing medium |
| US6000794A (en) * | 1994-10-27 | 1999-12-14 | Canon Kabushiki Kaisha | Image forming method |
| US6773101B2 (en) | 2000-08-23 | 2004-08-10 | Canon Kabushiki Kaisha | Ink-jet recording system and ink-jet recording method |
-
1991
- 1991-10-31 JP JP31329891A patent/JPH05125439A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0709223A1 (en) | 1994-10-27 | 1996-05-01 | Canon Kabushiki Kaisha | Recording medium, and image forming method and printed material making use of the same |
| US5679451A (en) * | 1994-10-27 | 1997-10-21 | Canon Kabushiki Kaisha | Recording medium |
| US6000794A (en) * | 1994-10-27 | 1999-12-14 | Canon Kabushiki Kaisha | Image forming method |
| US5804320A (en) * | 1994-10-31 | 1998-09-08 | Canon Kabushiki Kaisha | Recording medium |
| US5965252A (en) * | 1995-05-01 | 1999-10-12 | Canon Kabushiki Kaisha | Printing medium |
| US6558740B1 (en) | 1995-05-01 | 2003-05-06 | Canon Kabushiki Kaisha | Printing medium, production process thereof and image-forming process using the medium |
| US6773101B2 (en) | 2000-08-23 | 2004-08-10 | Canon Kabushiki Kaisha | Ink-jet recording system and ink-jet recording method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2567150B2 (en) | Manufacturing method of high strength low yield ratio line pipe material for low temperature | |
| US20060243352A1 (en) | Process for producing steel products having improved grain size properties and machinability | |
| JPS6311423B2 (en) | ||
| JPH05125439A (en) | Manufacture of non-heat-treated steel parts having high yield ratio | |
| JPS6376848A (en) | Cold rolled steel sheet for extra deep drawing and its manufacture | |
| JPH05105957A (en) | Production of heat resistant high strength bolt | |
| JPH0571657B2 (en) | ||
| JPH11241145A (en) | Austenitic stainless steel excellent in high temperature setting resistance and its production | |
| JP3385903B2 (en) | Method for producing high-strength hot-rolled steel sheet with excellent press formability | |
| JP2735161B2 (en) | High-strength, high-toughness non-heat treated steel for hot forging | |
| JPS5819438A (en) | Production of steel pipe having high strength and high toughness | |
| JPH0696742B2 (en) | High strength / high toughness non-heat treated steel manufacturing method | |
| JP3907986B2 (en) | Method for producing case-hardened steel with excellent cold workability and grain size characteristics | |
| JPH0978184A (en) | Case hardening steel excellent ion cold workability and crystalline grain coarsening characteristic | |
| JP3446394B2 (en) | Precipitation hardening stainless steel | |
| JPH0754041A (en) | Manufacture of steel for cold forging | |
| JPH07310144A (en) | Stainless steel excellent in cryogenic strength and toughness after superconducting material forming heat treatment | |
| JPH02310313A (en) | Production of weather-resisting steel | |
| JPS63213620A (en) | Manufacture of high strength steel pipe joint | |
| JP2521547B2 (en) | Low-temperature steel manufacturing method | |
| JPH05339629A (en) | Production of cr-mo steel having excellent strength and toughness | |
| JP2003342677A (en) | Steel for mechanical structure excellent in machinability and method for producing part for mechanical structure comprising the steel | |
| JPS6254018A (en) | Manufacture of high tensile steel superior in material characteristic after warm working | |
| JPH101737A (en) | Low alloy heat resistant steel, excellent in high temperature strength and toughness, and its production | |
| JPH0776722A (en) | Production of martensitic stainless steel excellent in sulfide cracking resistance |