JPH0571657B2 - - Google Patents
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- JPH0571657B2 JPH0571657B2 JP60214207A JP21420785A JPH0571657B2 JP H0571657 B2 JPH0571657 B2 JP H0571657B2 JP 60214207 A JP60214207 A JP 60214207A JP 21420785 A JP21420785 A JP 21420785A JP H0571657 B2 JPH0571657 B2 JP H0571657B2
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Description
［産業上の利用分野］
本発明は高靭性熱間鍛造非調質鋼材に関し、さ
らに詳しくは、熱間鍛造後放冷するだけで、焼入
れ−焼戻し処理材と同等の強度、靭性が得られる
高靭性熱間鍛造非調質鋼材に関する。
［従来技術］
従来、自動車や建設機械に用いられる機械構造
用部品は、多くの場合、機械構造用炭素鋼や合金
鋼を素材鋼として、これを熱間鍛造した後再加熱
し、焼入れ−焼戻し等の調質処理を行なつて、目
的、用途に応じた強度特性を付与して製造してい
る。
しかし、上記に説明したような熱処理における
多大の熱エネルギーのための費用、処理工程の増
加、仕掛り品の増大等のために、機械構造用部品
の製造は費用が高くならざるを得なかつた。
しかして、近年、鍛鋼品の製造において製造工
程の簡略化、特に、焼入れ−焼戻し工程を省略す
るために、JISG4501に規定された機械構造用炭
素鋼やJISG4106に規定された機械構造用マンガ
ン鋼およびマンガンクロム鋼に微量のＶ、Nb、
Ti等の析出硬化型合金元素が含有されている熱
間鍛造用非調質鋼を素材とし、熱間鍛造時の加熱
と鍛造およびその後の冷却によつて、調質処理を
行なわずにそのままで所望の特性が得られる非調
質鍛鋼品が注目されてきており、一部では既に実
用化されている。
通常このような非調質鍛鋼品は、1100〜1350℃
の温度から鍛造を開始し、1000〜1300℃の温度で
鍛造を終了し、その後大気中に放冷することによ
り製造されている。
［発明が解決しようとする問題点］
本発明は上記に説明したように、既に実用化さ
れている熱間鍛造用非調質鋼より製造されている
非調質鍛鋼品は、調質鍛鋼品と同じ強度が得られ
るが、靭性が低く、例えば、引張強さが80Kgｆ／
mm2以上になると室温における２mmＶノツチのシヤ
ルピー衝撃値が4.5Kgｆ・ｍ／cm2程度しか示さず、
同等の強度を有するS55C焼入れ−焼戻し材に要
求される６Kgｆ・ｍ／cm以上とはならない。この
原因は従来のこの非調質鍛鋼品は高温域において
加熱、加工され、その後放冷されるために、組織
が粗いオーステナイト粒から変態したフエライ
ト・パーライトであることと、強度が主としてパ
ーライトやＶ、Nb等の窒化物の析出によつて確
保されているためであることから、本発明者は、
従来の非調質鋼に高強度で優れた靭性を付与する
ため含有元素量を調整して、種々実験検討を重ね
た結果、引張強さが60Kgｆ／mm2〜90Kgｆ／mm2を有
する鋼において、熱間鍛造後放冷された状態で組
織が粗いフエライト・パーライトであつても、鍛
造後の焼入れ−焼戻し処理を不要とし、高強度で
優れた靭性を示し、さらに、被削性の良好な高靭
性熱間鍛造非調質鋼材を開発したのである。
［問題点を解決するための手段］
本発明に係る高靭性熱間鍛造非調質鋼材は、
(1) C0.10〜0.25wt％、Si0.05〜1.0wt％、
Mn0.6〜2.5wt％、Cr2.0wt％以下、
V0.03〜0.30wt％、Al0.015〜0.060wt％、
N0.003〜0.020wt％、
S0.010wt％を越え0.12wt％以下
を含有し、残部Feおよび不純物からなり、
かつ、Mn、Cr、Ｖの含有量が
（Mn＋Cr）／Ｖ＝10.0以上20.0以下
の式を満足する組成を有し、熱間鍛造後大気中
で冷却した状態で、引張強さ60〜90Kgｆ／mm2
で、衝撃値6.0Kg・ｍ／cm2以上の高靭性を有す
ることを特徴とする高靭性熱間鍛造非調質鋼材
を第１の発明とし、
(2) C0.10〜0.25wt％、Si0.05〜1.0wt％、
Mn0.6〜2.5wt％、Cr2.0wt％以下、
V0.03〜0.30wt％、Al0.015〜0.060wt％、
N0.003〜0.020wt％、
S0.010wt％を越え、0.12wt％以下
を含有し、さらに、
Ni1.0wt％以下、Mo0.50wt％以下、
Nb0.005〜0.05wt％
のうちから選んだ１種または２種以上
を含有し、残部Feおよび不純物からなり、
かつ、Mn、Cr、Ｖの含有量が
（Mn＋Cr）／Ｖ＝10.0以上20.0以下
の式を満足する組成を有し、熱間鍛造後大気中
で冷却した状態で、引張強さ60〜90Kgｆ／mm2
で、衝撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有
することを特徴とする高靭性熱間鍛造非調質鋼
材を第２の発明とし、
(3) C0.10〜0.25wt％、Si0.05〜1.0wt％、
Mn0.6〜2.5wt％、Cr2.0wt％以下、
V0.03〜0.30wt％、Al0.015〜0.060wt％、
N0.003〜0.020wt％、
S0.010wt％を越え0.12wt％以下
を含有し、また、
Pb0.30wt％以下、Zr0.20wt％以下、
Ca0.01wt％以下、Te0.10wt％以下
のうちから選んだ１種または２種以上を含有
し、残部Feおよび不純物からなり、
かつ、Mn、Cr、Ｖの含有量が
（Mn＋Cr）／Ｖ＝10.0以上20.0以下
の式を満足する組成を有し、熱間鍛造後大気中
で冷却した状態で、引調強さ60〜90Kgｆ／mm2
で、衝撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有
することを特徴とする高靭性熱間鍛造非調質鋼
材を第３の発明とし、
(4) C0.10〜0.25wt％、Si0.05〜1.0wt％、
Mn0.6〜2.5wt％、Cr2.0wt％以下、
V0.03〜0.30wt％、Al0.015〜0.060wt％、
N0.003〜0.020wt％、
S0.010wt％を越え0.12wt％以下
を含有し、さらに、
Ni1.0wt％以下、Mo0.50wt％以下、
Nb0.005〜0.05wt％
のうちから選んだ１種または２種以上
を含有し、また、
Pb0.30wt％以下、Zr0.20wt％以下、
Ca0.01wt％以下、Te0.10wt％以下
のうちから選んだ１種または２種以上
を含有し、残部Feおよび不純物からなり、
かつ、Mn、Cr、Ｖの含有量が
（Mn＋Cr）／Ｖ＝10.0以上20.0以下
の式を満足する組成を有し、熱間鍛造後大気中
で冷却した状態で、引張強さ60〜90Kgｆ／mm2
で、衝撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有
することを特徴とする高靭性熱間鍛造非調質鋼
材を第４の発明とする４つの発明よりなるもの
である。
本発明に係る高靭性熱間鍛造非調質鋼材につい
て、以下詳細に説明する。
先ず、本発明に係る高靭性熱間鍛造非調質鋼材
の含有成分および成分割合について説明する。
Ｃはパーライト量を増大させて鍛鋼品の強度を
高めると共にＶと炭化物を形成し、その析出強化
作用を発揮させるために必須の元素であり、含有
量が0.10wt％未満ではこのような強化効果は少な
く、また、0.25wt％を越えると焼入れ−焼戻し材
の衝撃値より低くなり、靭性が不足する。よつ
て、Ｃ含有量は0.10〜0.25wt％とする。
Siは脱酸の他に、鍛造放冷後のフエライト組織
を強化する上で有効な元素であり、含有量が
0.05wt％未満ではこのような効果は少なく、ま
た、1.0wt％を越えると靭性と被削性が劣化する。
よつて、Si含有量は0.05〜1.0wt％とする。
Mnは脱酸、脱硫元素で、鍛鋼品の強度を増大
させ、靭性を向上させるために必須の元素であ
り、含有量が0.6wt％未満ではこのような効果は
少なく、また、2.5wt％を越えると靭性が低下し、
被削性に有害な影響を与える。よつて、Mn含有
量は0.6〜2.5wt％とする。
CrはMnと同様に鍛鋼品の強度を増大し、靭性
を向上させるのに有用な元素であり、含有量が
2.0wt％を越えるとベイナイトが生成して靭性が
低下するようになる。よつて、Cr含有量は2.0wt
％以下とする。
Ｖは鍛造後の冷却においてＣおよびＮと炭窒化
物を形成して強度を付与する元素であり、含有量
が0.03wt％未満ではこのような効果は少なく、ま
た、0.30wt％を越えると効果が飽和する。よつ
て、Ｖ含有量は0.03〜0.30wt％とする。
Alは脱酸効果と結晶粒度の微細化に有効な元
素であり、含有量が0.015wt％未満ではこのよう
な効果は少なく、また、0.060wt％を越えて含有
されると効果も含有量が増加する割には僅かであ
り、かつ、被削性にも有害な影響を与える。よつ
て、Al含有量は0.015〜0.060wt％とする。
ＮはＶやAlと結合して炭窒化物を形成して結
晶粒を微細化し、鋼を変化するために有用な元素
であり、含有量が0.003wt％未満ではこの効果は
少なく、また、0.020wt％を越えて多量に含有さ
せても効果の増大は期待できず、かつ、靭性の劣
化を招く。よつて、Ｎ含有量は0.003〜0.020wt％
とする。
Ｓは被削性を向上させ、鍛造時に機械加工を行
う場合に有効な元素であり、含有量が0.010wt％
未満ではこの効果は少なく、また、0.12wt％を越
えて多量に含有させると被削性の効果に顕著なも
のが認められず、靭性が低下するようになる。よ
つて、Ｓ含有量は0.010〜0.12wt％とする。
Ni、Moは共に靭性を損なうことなく、鍛鋼品
の強度を増大させる元素であり、多量に含有させ
るとベイトナイトが生成し靭性が低下する。よつ
て、
Ni含有量は1.0wt％、Mo含有量は0.50wt％以
下とする。
Nbは鍛造時のオーステナイト結晶粒の成長を
抑制する元素であり、靭性がさらに向上するもの
であり、含有量が0.005wt％未満ではこのような
効果は少なく、また、0.05wt％を越えると結晶粒
成長を抑制する効果の向上は期待できない。よつ
て、Nb含有量は0.005〜0.050wt％とする。
Mn、Cr、Ｖの含有量を（Mn＋Cr）／Ｖ＝
10.0〜20.0とするのは、Ｖは鍛造後の冷却におい
て炭窒化物を形成して鋼を強化する元素であり、
含有量が0.30wt％までは含有量が多くなるに従つ
て強度が向上するが、靭性の低下が著しくなり、
また、Mn、Crは組織を微細にして靭性を向上さ
せる元素であるので、焼入れ−焼戻し材と同等の
強度、靭性のバランスを確保するためには、
Mn、CrおよびＶの含有量のバランスを考慮しな
ければならず、特に（Mn＋Cr）／Ｖ＝10.0〜
20.0を満足するようにMn含有量、Cr含有量およ
びＶ含有量を調整して、優れた靭性を確保するの
である。
また、Pb0.30wt％以下、Zr0.20wt％以下、
Ca0.01wt％以下、Te0.10wt％以下を含有させる
ことにより被削性を向上させることができ、さら
に、鍛造後の機械加工を行う場合に有効であり、
これらの元素含有量を越えて多量に含有させても
被削性に対して顕著な効果は期待できず、かつ、
靭性が低下する。よつて、Pb含有量0.30wt％以
下、Zn含有量0.20wt％以下、Ca含有量0.01wt％
以下、Te含有量0.10wt％以下とする。
本発明に係る高靭性熱間鍛造非調質鋼材は、上
記に説明した含有成分および成分割合の組成を有
する鋼を従来技術の非調質熱間鍛造品の場合と同
様、常法により熱間鍛造後大気中で冷却した状態
で、引張強さ60〜90Kgｆ／mm2の高強度で、衝撃値
6.0Kgｆ・ｍ／cm2以上の優れた靭性が得られる。
特に、引張強さ80Kgｆ／mm2以上であつても衝撃値
7.5Kgｆ・ｍ／cm2以上の高靭性が得られる。
［実施例］
次に本発明に係る高靭性熱間鍛造非調質鋼材の
実施例を説明する。
実施例
第１表および第２表に示す含有成分および成分
割合の鋼を高周波炉において溶製し、鋳造後50mm
φに圧延して、長さ250mmｌに切断した。
さらに、1250℃の温度に加熱してハンマーで直
径35mmの丸棒に鍛伸した。仕上成形時の終了温度
は1150℃で、その後大気中に放冷した。ただし、
No.35の供試鋼はS55Cであり、熱間鍛造後再加熱
して焼入れ−焼戻し処理を行なつた。
これらの丸棒の中央部より長手方向にJIS4号引
張試験片およびJIS3号衝撃試験片を採取し、引張
強さ、シヤルピー衝撃値を求めた。
この第１表および第２表において、No.１〜No.27
は本発明に係る高靭性熱間鍛造非調質鋼材であ
り、No.28〜No.32、No.35〜No.40は比較鋼である。
この第１表および第２表から、本発明に係る高
靭性熱間鍛造非調質鋼材は、No.35と同等またはそ
れ以上の強度、靭性を具備しており、比較鋼No.28
は（Mn＋Cr）／Ｖの値が低く、比較鋼No.30はＣ
含有量が多く、比較鋼No.29は（Mn＋Cr）／Ｖの
値が低く、Ｃ含有量が高いので、何れも靭性が不
足していることがわかる。
その他の比較鋼No.31、No.32、No.36〜No.40は何れ
も0.2％耐力、降伏比において劣つていることが
分かる。
[Industrial Application Field] The present invention relates to high toughness hot forged non-tempered steel materials, and more specifically, to high toughness hot forged non-tempered steel materials that can obtain strength and toughness equivalent to hardened and tempered materials simply by allowing them to cool after hot forging. Concerning toughness hot forged non-thermal steel materials. [Prior art] Conventionally, mechanical structural parts used in automobiles and construction machinery are often made of mechanical structural carbon steel or alloy steel, which is hot-forged, reheated, and then quenched and tempered. It is manufactured by undergoing tempering treatments such as these to impart strength characteristics according to the purpose and use. However, due to the cost of a large amount of thermal energy in heat treatment, an increase in processing steps, an increase in work in progress, etc. as explained above, manufacturing of mechanical structural parts has become expensive. . Therefore, in recent years, in order to simplify the manufacturing process in manufacturing forged steel products, in particular to omit the quenching and tempering process, carbon steel for machine structures specified in JISG4501, manganese steel for machine structures specified in JISG4106, and Trace amounts of V, Nb, and manganese chromium steel
The raw material is non-thermal steel for hot forging that contains precipitation hardening alloy elements such as Ti, and it is made as it is without heat treatment by heating during hot forging, forging, and cooling afterwards. Non-thermal forged steel products that can obtain desired properties have been attracting attention, and some have already been put into practical use. Normally, such non-thermal forged steel products are heated at 1100 to 1350℃.
It is manufactured by starting forging at a temperature of 1,000 to 1,300 degrees Celsius, and then leaving it to cool in the atmosphere. [Problems to be Solved by the Invention] As explained above, the present invention is directed to non-tempered forged steel products manufactured from non-tempered steel for hot forging that has already been put into practical use. The same strength can be obtained, but the toughness is lower, for example, the tensile strength is 80Kgf/
When the value exceeds mm 2 , the 2 mm V notch at room temperature exhibits a sharpy impact value of only about 4.5 Kgf・m/cm 2 ,
It cannot exceed 6 kgf・m/cm, which is required for S55C hardened and tempered material with the same strength. The reason for this is that conventional non-thermal forged steel products are heated and worked in a high temperature range and then left to cool, so the structure is ferrite/pearlite transformed from coarse austenite grains, and the strength is mainly pearlite or V. This is because it is ensured by the precipitation of nitrides such as Nb.
In order to impart high strength and excellent toughness to conventional non-tempered steel, we adjusted the content of elements and conducted various experiments. As a result, we found that steel with a tensile strength of 60Kgf/mm 2 to 90Kgf/mm 2 Even if ferrite/pearlite has a coarse structure when left to cool after hot forging, it does not require quenching and tempering after forging, exhibits high strength and excellent toughness, and has good machinability. They developed a high-toughness hot-forged non-thermal steel material. [Means for solving the problems] The high toughness hot forged non-thermal steel material according to the present invention contains: (1) C0.10~0.25wt%, Si0.05~1.0wt%, Mn0.6~2.5wt% %, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003~0.020wt%, S over 0.010wt% and 0.12wt% or less, the balance being Fe and impurities. and has a composition in which the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and has a tensile strength of 60 when cooled in the air after hot forging. ~90Kgf/ mm2
The first invention is a high-toughness hot-forged non-thermal steel material characterized by having high toughness with an impact value of 6.0 Kg・m/cm 2 or more, (2) C0.10-0.25wt%, Si0 .05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003~0.020wt%, S0.010wt% 0.12wt% or less, and further contains one or more selected from Ni1.0wt% or less, Mo0.50wt% or less, Nb0.005 to 0.05wt%, and the balance is Fe and impurities. and has a composition in which the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and has a tensile strength of 60 when cooled in the air after hot forging. ~90Kgf/ mm2
The second invention is a high-toughness hot-forged non-thermal steel material characterized by having high toughness with an impact value of 6.0 Kgf・m/cm 2 or more, (3) C0.10-0.25wt%, Si0 .05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003~0.020wt%, S0.010wt% Contains 0.12 wt% or less, and also contains one or more selected from Pb 0.30 wt% or less, Zr 0.20 wt% or less, Ca 0.01 wt% or less, Te 0.10 wt% or less, and the remainder It consists of Fe and impurities, and has a composition in which the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and when cooled in the atmosphere after hot forging, it is Strength 60~90Kgf/ mm2
The third invention is a high-toughness hot-forged non-thermal steel material characterized by having high toughness with an impact value of 6.0 Kgf・m/cm 2 or more, (4) C0.10-0.25wt%, Si0 .05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003~0.020wt%, S0.010wt% Contains not more than 0.12wt% of Ni, and further contains one or more selected from Ni1.0wt% or less, Mo0.50wt% or less, Nb0.005 to 0.05wt%, and Pb0.30wt%. % or less, Zr 0.20wt% or less, Ca 0.01wt% or less, Te 0.10wt% or less, and the remainder consists of Fe and impurities, and contains Mn, Cr, and V. It has a composition that satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and has a tensile strength of 60 to 90 Kgf/mm 2 when cooled in the air after hot forging.
This invention consists of four inventions, with the fourth invention being a high-toughness hot-forged non-thermal steel material characterized by having high toughness with an impact value of 6.0 Kgf·m/cm 2 or more. The high toughness hot forged non-thermal steel material according to the present invention will be described in detail below. First, the components and component ratios of the high toughness hot forged non-thermal steel material according to the present invention will be explained. C is an essential element to increase the amount of pearlite and increase the strength of forged steel products, and also to form carbides with V and exhibit its precipitation strengthening effect.If the content is less than 0.10wt%, this strengthening effect is Moreover, if it exceeds 0.25wt%, the impact value will be lower than that of the quenched-tempered material, resulting in insufficient toughness. Therefore, the C content is set to 0.10 to 0.25 wt%. In addition to deoxidizing, Si is an effective element for strengthening the ferrite structure after forging and cooling, and its content is
If the content is less than 0.05wt%, this effect will be small, and if it exceeds 1.0wt%, the toughness and machinability will deteriorate.
Therefore, the Si content is set to 0.05 to 1.0 wt%. Mn is a deoxidizing and desulfurizing element, and is an essential element for increasing the strength and toughness of forged steel products.If the content is less than 0.6wt%, this effect will be small, and if the content is less than 2.5wt%, If it exceeds, the toughness decreases,
Has a detrimental effect on machinability. Therefore, the Mn content is set to 0.6 to 2.5 wt%. Like Mn, Cr is an element useful for increasing the strength and toughness of forged steel products, and its content is
If it exceeds 2.0wt%, bainite will be generated and the toughness will decrease. Therefore, the Cr content is 2.0wt
% or less. V is an element that forms carbonitrides with C and N during cooling after forging and imparts strength.If the content is less than 0.03wt%, this effect will be small, and if the content exceeds 0.30wt%, the effect will be reduced. becomes saturated. Therefore, the V content is set to 0.03 to 0.30 wt%. Al is an element that is effective in deoxidizing and refining the grain size.If the content is less than 0.015wt%, this effect will be small, and if the content exceeds 0.060wt%, the effect will be reduced. The increase is small and has a detrimental effect on machinability. Therefore, the Al content is set to 0.015 to 0.060 wt%. N is a useful element for changing steel by combining with V and Al to form carbonitrides and refining crystal grains.If the content is less than 0.003wt%, this effect is small; Even if the content exceeds wt%, no increase in the effect can be expected and the toughness will deteriorate. Therefore, the N content is 0.003 to 0.020wt%
shall be. S is an element that improves machinability and is effective when performing machining during forging, and the content is 0.010wt%.
If the content is less than 0.12wt%, this effect will be small, and if the content exceeds 0.12wt%, no significant effect on machinability will be observed and the toughness will decrease. Therefore, the S content is set to 0.010 to 0.12 wt%. Both Ni and Mo are elements that increase the strength of steel forgings without impairing their toughness, and if they are included in large amounts, baitoonite will be formed and the toughness will decrease. Therefore, the Ni content is 1.0wt% and the Mo content is 0.50wt% or less. Nb is an element that suppresses the growth of austenite crystal grains during forging, further improving toughness. If the content is less than 0.005wt%, this effect is small, and if the content exceeds 0.05wt%, the crystallization No improvement in the effect of suppressing grain growth can be expected. Therefore, the Nb content is set to 0.005 to 0.050 wt%. The content of Mn, Cr, and V is (Mn+Cr)/V=
10.0 to 20.0 is because V is an element that forms carbonitrides and strengthens steel during cooling after forging.
When the content is up to 0.30wt%, the strength increases as the content increases, but the toughness decreases significantly.
In addition, Mn and Cr are elements that refine the structure and improve toughness, so in order to ensure the same balance of strength and toughness as quenched and tempered materials,
The balance of Mn, Cr and V contents must be considered, especially (Mn+Cr)/V=10.0~
Excellent toughness is ensured by adjusting the Mn content, Cr content, and V content so as to satisfy 20.0. In addition, Pb 0.30wt% or less, Zr 0.20wt% or less,
Machinability can be improved by containing Ca 0.01wt% or less and Te 0.10wt% or less, and is also effective when performing machining after forging.
Even if the content of these elements is exceeded, no significant effect on machinability can be expected, and
Toughness decreases. Therefore, Pb content is 0.30wt% or less, Zn content is 0.20wt% or less, and Ca content is 0.01wt%.
Hereinafter, the Te content shall be 0.10wt% or less. The high-toughness hot-forged non-heat-treated steel material according to the present invention is obtained by hot-working steel having the composition of the above-described components and component ratios in the same manner as in the case of non-tempered hot-forged products of the prior art. When cooled in the atmosphere after forging, it has a high tensile strength of 60 to 90 Kgf/ mm2 and a low impact value.
Excellent toughness of 6.0Kgf・m/cm 2 or more can be obtained.
In particular, even if the tensile strength is 80Kgf/mm2 or more, the impact value
High toughness of 7.5Kgf・m/cm 2 or more can be obtained. [Example] Next, an example of a high-toughness hot-forged non-thermal steel material according to the present invention will be described. Example Steel with the components and ratios shown in Tables 1 and 2 was melted in a high frequency furnace, and after casting, the steel was 50mm thick.
It was rolled to φ and cut into lengths of 250 mml. Furthermore, it was heated to a temperature of 1250℃ and forged into a round bar with a diameter of 35mm using a hammer. The finishing temperature during final molding was 1150°C, and then it was allowed to cool in the atmosphere. however,
The test steel No. 35 was S55C, which was hot-forged, reheated, and then quenched and tempered. A JIS No. 4 tensile test piece and a JIS No. 3 impact test piece were taken from the center of each of these round bars in the longitudinal direction, and the tensile strength and Charpy impact value were determined. In this Table 1 and Table 2, No. 1 to No. 27
No. 28 to No. 32 and No. 35 to No. 40 are comparative steels. From Tables 1 and 2, it can be seen that the high toughness hot forged non-tempered steel material according to the present invention has strength and toughness equivalent to or higher than that of comparative steel No. 28.
has a low value of (Mn+Cr)/V, and comparative steel No. 30 has a low value of (Mn+Cr)/V.
Comparative steel No. 29 has a low value of (Mn+Cr)/V and a high C content, so it can be seen that both of them lack toughness. It can be seen that the other comparison steels No. 31, No. 32, and No. 36 to No. 40 are all inferior in 0.2% proof stress and yield ratio.
【表】
＊：熱処理は熱間鍛造後大気中で放冷
[Table] *: Heat treatment is cooling in the atmosphere after hot forging.
【表】
［発明の効果］
以上説明したように、本発明に係る高靭性熱間
鍛造非調質鋼材は上記の構成であるので、従来は
熱間鍛造後、再加熱して焼入れ−焼戻しにより高
靭性が要求される部品を製造していたが、熱間鍛
造後に放冷するだけで従来と同等またはそれ以上
の高靭性および高強度が得られるという優れた効
果を有するものである。[Table] [Effects of the Invention] As explained above, since the high toughness hot forged non-tempered steel material according to the present invention has the above structure, conventionally, after hot forging, it was reheated and then quenched and tempered. Although parts that require high toughness have been manufactured, this method has the excellent effect of providing high toughness and strength equal to or higher than conventional methods simply by allowing it to cool after hot forging.
Claims (1)
冷却した状態で、引張強さ60〜90Kgｆ／mm2で、衝
撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有すること
を特徴とする高靭性熱間鍛造非調質鋼材。 ２ C0.10〜0.25wt％、Si0.05〜1.0wt％、 Mn0.6〜2.5wt％、Cr2.0wt％以下、 V0.03〜0.30wt％、Al0.015〜0.060wt％、 N0.003〜0.020wt％、 S0.010wt％を越え0.12wt％以下 を含有し、さらに、 Ni1.0wt％以下、Mo0.50wt％以下、 Nb0.005〜0.05wt％ のうちから選んだ１種または２種以上を含有し、
残部Feおよび不純物からなり、 かつ、Mn、Cr、Ｖの含有が （Mn＋Cr）／Ｖ＝10.0以上20.0以下 の式を満足する組成を有し、熱間鍛造後大気中で
冷却した状態で、引張強さ60〜90Kgｆ／mm2で、衝
撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有すること
を特徴とする高靭性熱間鍛造非調質鋼材。 ３ C0.10〜0.25wt％、Si0.05〜1.0wt％、 Mn0.6〜2.5wt％、Cr2.0wt％以下、 V0.03〜0.30wt％、Al0.015〜0.060wt％、 N0.003〜0.020wt％、 S0.010wt％を越え0.12wt％以下 を含有し、また、 Pb0.30wt％以下、Zr0.20wt％以下、 Ca0.01wt％以下、Te0.10wt％以下 のうちから選んだ１種または２種以上を含有し、
残部Feおよび不純物からなり、 かつ、Mn、Cr、Ｖの含有量が （Mn＋Cr）／Ｖ＝10.0以上20.0以下 の式を満足する組成を有し、熱間鍛造後大気中で
冷却した状態で、引張強さ60〜90Kgｆ／mm2で、衝
撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有すること
を特徴とする高靭性熱間鍛造非調質鋼材。 ４ C0.10〜0.25wt％、Si0.05〜1.0wt％、 Mn0.6〜2.5wt％、Cr2.0wt％以下、 V0.03〜0.30wt％、Al0.015〜0.060wt％、 N0.003〜0.020wt％、 S0.010wt％を越え0.12wt％以下 を含有し、さらに、 Ni1.0wt％以下、Mo0.50wt％以下、 Nb0.005〜0.05wt％ のうちから選んだ１種または２種以上を含有し、
また、 Pb0.30wt％以下、Zr0.20wt％以下、 Ca0.01wt％以下、Te0.10wt％以下 のうちから選んだ１種または２種以上を含有し、
残部Feおよび不純物からなり、 かつ、Mn、Cr、Ｖの含有量が （Mn＋Cr）／Ｖ＝10.0以上20.0以下 の式を満足する組成を有し、熱間鍛造後大気中で
冷却した状態で、引張強さ60〜90Kgｆ／mm2で、衝
撃値6.0Kgｆ・ｍ／cm2以上の高靭性を有すること
を特徴とする高靭性熱間鍛造非調質鋼材。[Claims] 1 C0.10-0.25wt%, Si0.05-1.0wt%, Mn0.6-2.5wt%, Cr2.0wt% or less, V0.03-0.30wt%, Al0.015-0.060 wt%, N0.003 to 0.020wt%, S more than 0.010wt% and less than 0.12wt%, with the balance consisting of Fe and impurities, and the content of Mn, Cr, and V is (Mn+Cr)/V=10.0 It has a composition that satisfies the formula below 20.0, and has a tensile strength of 60 to 90 Kgf/mm 2 and high toughness of 6.0 Kgf・m/cm 2 or more in impact value when cooled in the atmosphere after hot forging. A high-toughness hot-forged non-thermal steel material characterized by having the following properties. 2 C0.10~0.25wt%, Si0.05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003 Contains ~0.020wt%, S of more than 0.010wt% and 0.12wt% or less, and one or two selected from Ni1.0wt% or less, Mo0.50wt% or less, Nb0.005 to 0.05wt%. Contains more than
The balance consists of Fe and impurities, and the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and after hot forging and cooling in the atmosphere, it is A high-toughness hot-forged non-thermal steel material characterized by having a strength of 60 to 90 Kgf/mm 2 and high toughness with an impact value of 6.0 Kgf·m/cm 2 or more. 3 C0.10~0.25wt%, Si0.05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003 ~0.020wt%, S exceeding 0.010wt% and 0.12wt% or less, and 1 selected from Pb 0.30wt% or less, Zr 0.20wt% or less, Ca 0.01wt% or less, Te 0.10wt% or less Contains a species or two or more species,
The balance consists of Fe and impurities, and the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and after being cooled in the atmosphere after hot forging, A high-toughness hot-forged non-thermal steel material characterized by having a tensile strength of 60 to 90 Kgf/mm 2 and high toughness with an impact value of 6.0 Kgf·m/cm 2 or more. 4 C0.10~0.25wt%, Si0.05~1.0wt%, Mn0.6~2.5wt%, Cr2.0wt% or less, V0.03~0.30wt%, Al0.015~0.060wt%, N0.003 Contains ~0.020wt%, S of more than 0.010wt% and 0.12wt% or less, and one or two selected from Ni1.0wt% or less, Mo0.50wt% or less, Nb0.005 to 0.05wt%. Contains more than
In addition, it contains one or more selected from Pb 0.30wt% or less, Zr 0.20wt% or less, Ca 0.01wt% or less, Te 0.10wt% or less,
The balance consists of Fe and impurities, and the content of Mn, Cr, and V satisfies the formula (Mn + Cr)/V = 10.0 or more and 20.0 or less, and after being cooled in the atmosphere after hot forging, A high-toughness hot-forged non-thermal steel material characterized by having a tensile strength of 60 to 90 Kgf/mm 2 and high toughness with an impact value of 6.0 Kgf·m/cm 2 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21420785A JPS6274055A (en) | 1985-09-27 | 1985-09-27 | Non-heattreated steel with high toughness for hot forging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21420785A JPS6274055A (en) | 1985-09-27 | 1985-09-27 | Non-heattreated steel with high toughness for hot forging |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6274055A JPS6274055A (en) | 1987-04-04 |
| JPH0571657B2 true JPH0571657B2 (en) | 1993-10-07 |
Family
ID=16652004
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0675747B2 (en) * | 1986-02-12 | 1994-09-28 | 住友金属工業株式会社 | Manufacturing method of non-heat treated steel for hot forging |
| JPS62196359A (en) * | 1986-02-24 | 1987-08-29 | Sumitomo Metal Ind Ltd | Non-heattreated steel for hot forging and production thereof |
| JPH0621319B2 (en) * | 1986-03-04 | 1994-03-23 | 愛知製鋼株式会社 | Non-heat treated steel for hot forging |
| JP2583776B2 (en) * | 1987-12-30 | 1997-02-19 | 愛知製鋼株式会社 | Non-heat treated steel for hot forging |
| JPH0663025B2 (en) * | 1990-01-17 | 1994-08-17 | 新日本製鐵株式会社 | Method for producing high strength and high toughness hot forged non-heat treated steel |
| JP2743116B2 (en) * | 1990-07-27 | 1998-04-22 | 愛知製鋼 株式会社 | Non-heat treated steel for hot forging |
| JPH059652A (en) * | 1991-07-04 | 1993-01-19 | Sanyo Special Steel Co Ltd | Non-heat treated steel for hot forging with excellent machinability |
| JP3139876B2 (en) * | 1993-04-05 | 2001-03-05 | 新日本製鐵株式会社 | Method of manufacturing non-heat treated steel for hot forging and non-heat treated hot forged product, and non-heat treated hot forged product |
| KR101758470B1 (en) | 2015-11-12 | 2017-07-17 | 주식회사 포스코 | Non-quenched and tempered wire rod having excellent cold workability and method for manufacturing same |
| CN114525454B (en) * | 2022-02-22 | 2023-02-21 | 承德建龙特殊钢有限公司 | A kind of tellurium-containing non-quenched and tempered steel and its production method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59100256A (en) * | 1982-11-30 | 1984-06-09 | Nippon Kokan Kk <Nkk> | Non-thermal steel for hot forging with excellent toughness |
| JPS59170220A (en) * | 1983-03-18 | 1984-09-26 | Nippon Kokan Kk <Nkk> | Production of un-tempered type low temperature steel plate |
| JPS59200741A (en) * | 1983-04-28 | 1984-11-14 | Nippon Steel Corp | High strength steel having excellent resistance to plating brittleness and processability by forging |
| JPS6075517A (en) * | 1983-09-29 | 1985-04-27 | Kobe Steel Ltd | Manufacture of nonrefined forged steel article |
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1985
- 1985-09-27 JP JP21420785A patent/JPS6274055A/en active Granted
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| JPS6274055A (en) | 1987-04-04 |
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