JP3274028B2 - Manufacturing method of non-heat treated high strength high toughness hot forged parts - Google Patents
Manufacturing method of non-heat treated high strength high toughness hot forged partsInfo
- Publication number
- JP3274028B2 JP3274028B2 JP21927594A JP21927594A JP3274028B2 JP 3274028 B2 JP3274028 B2 JP 3274028B2 JP 21927594 A JP21927594 A JP 21927594A JP 21927594 A JP21927594 A JP 21927594A JP 3274028 B2 JP3274028 B2 JP 3274028B2
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- Japan
- Prior art keywords
- forging
- temperature
- rolling
- steel
- heating
- 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
【０００１】[0001]
【産業上の利用分野】本発明は、高強度高靭性の自動車
部品の製造法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high strength and high toughness automobile part.
【０００２】[0002]
【従来の技術】高強度高靭性自動車部品は、素材を熱間
鍛造後、焼入焼戻し処理により製造されてきたが、近年
コスト低減を目的として、熱処理不要の熱間鍛造用非調
質棒鋼が用いられている。特公平01-11083号公報「高強
度非調質棒鋼の製造方法」では、高Mn-V鋼にＳを多量に
添加し、1000℃以下の温度で圧延および鍛造することに
より、 MnS介在物の展伸をはかり、特に常温の衝撃特性
を改善した高強度非調質棒鋼の製造方法が開示されてい
る。2. Description of the Related Art High-strength, high-toughness automotive parts have been manufactured by quenching and tempering after hot forging of raw materials. Used. In Japanese Patent Publication No. 01-11083, "Method of manufacturing high-strength non-heat treated steel bars", a large amount of S is added to a high Mn-V steel, and rolling and forging are performed at a temperature of 1000 ° C or less to reduce the inclusion of MnS inclusions. A method for producing a high-strength non-heat-treated steel bar which is stretched and has particularly improved impact characteristics at room temperature is disclosed.
【０００３】特公平01-11083号公報「高強度非調質棒鋼
の製造方法」では、靭性確保のため鍛造温度を1000℃以
下という低温に設定する必要があり、通常熱間鍛造に使
用される温度である1250℃程度で鍛造する場合と比べ
て、熱間変形抵抗が高くなるため金型の寿命が短くなり
鍛造費用の増大を招く。また熱間変形抵抗が高いため鍛
造形状不良が発生しやすいという難点もある。In Japanese Patent Publication No. H01-11083, "Method of manufacturing high-strength non-heat treated steel bars", it is necessary to set the forging temperature to a low temperature of 1000 ° C. or less in order to secure toughness, and it is usually used for hot forging. As compared with the case of forging at a temperature of about 1250 ° C., the hot deformation resistance is increased, so that the life of the mold is shortened and the forging cost is increased. In addition, there is also a disadvantage that forging shape defects easily occur due to high hot deformation resistance.
【０００４】[0004]
【発明が解決しようとする課題】本発明は、上記問題点
を解決するため、通常の熱間鍛造温度範囲である1100〜
1250℃で鍛造しても高靭性の非調質高強度熱間鍛造部品
を安価に製造する方法を提供する。DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a normal hot forging temperature range of 1100 to 1100.
Provided is a method for inexpensively producing a non-refined, high-strength, high-strength hot-forged part that has high toughness even when forged at 1250 ° C.
【０００５】[0005]
【課題を解決するための手段】本発明者らは鋭意研究の
結果、制御圧延および制御冷却して結晶粒の微細化を計
った棒鋼を熱間鍛造するに際して、前記微細結晶粒を維
持するため、その鍛造加熱温度、鍛造加熱保持時間、お
よび昇温速度を制御することにより、非調質高強度熱間
鍛造部品の衝撃特性の向上が図れることを見出した。す
なわち、本発明は、 （１） 熱間鍛造用非調質鋼片を、加熱温度８００〜１
０５０℃、圧延仕上り温度８５０℃以下の圧延条件で圧
延し、圧延終了後５００℃までの冷却速度を０．５℃／
ｓｅｃ以上となるように冷却して、ＪＩＳオーステナイ
ト結晶粒度番号で７番以上の鋼を製造し、ついでこの鋼
を、鍛造加熱保持温度１２００〜１２５０℃、鍛造加熱
保持時間３００秒以下、および鍛造加熱保持温度までの
昇温速度を１℃／ｓｅｃ以上として熱間鍛造をおこなう
ことを特徴とする非調質高強度高靭性熱間鍛造部品の製
造方法である。Means for Solving the Problems As a result of intensive studies, the present inventors have found that, when hot forging a steel bar whose grain size has been reduced by controlled rolling and controlled cooling, the fine grain is maintained. By controlling the forging heating temperature, the forging heating holding time, and the heating rate, it was found that the impact characteristics of a non-heat treated high strength hot forged part can be improved. That is, the present invention provides: (1) a non-heat treated steel slab for hot forging;
Rolling is performed at a rolling condition of 050 ° C. and a finishing temperature of 850 ° C. or less.
It cooled such that the above sec, to produce a seventh or more steel in JIS austenite grain size number, then the steel, forged heat holding temperature from 1200 to 1,250 ° C., forging heating
A method for producing a non-finished, high-strength, high-toughness hot forged part, characterized in that hot forging is performed with a holding time of 300 seconds or less and a rate of temperature rise to a forging heat holding temperature of 1 ° C./sec or more.
【０００６】（２） 重量％で、Ｃ：０．２〜０．６
％、Ｍｎ：０．８〜２．０％、Ｐ：０．０１５％以下、
Ｎ：０．００５〜０．０２％を含み、且つＶ：０．０１
〜０．２％、Ｔｉ：０．００１〜０．０２％およびＮ
ｂ：０．００５〜０．１％から選択された１種以上の元
素を含有し、残部Ｆｅおよび不可避不純物からなる鋼片
を、加熱温度８００〜１０５０℃、圧延仕上り温度８５
０℃以下の圧延条件で圧延し、圧延終了後５００℃まで
の冷却速度を０．５℃／ｓｅｃ以上となるように冷却し
て、ＪＩＳオーステナイト結晶粒度番号で７番以上の鋼
を製造し、ついでこの鋼を、鍛造加熱保持温度１２００
〜１２５０℃、鍛造加熱保持時間３００秒以下、および
鍛造加熱保持温度までの昇温速度を１℃／ｓｅｃ以上と
して熱間鍛造をおこなうことを特徴とする非調質高強度
高靭性熱間鍛造部品の製造方法。(2) C: 0.2-0.6% by weight
%, Mn: 0.8 to 2.0%, P: 0.015% or less,
N: 0.005 to 0.02%, and V: 0.01
~ 0.2%, Ti: 0.001-0.02% and N
b: A steel slab containing at least one element selected from 0.005 to 0.1%, the balance being Fe and unavoidable impurities was heated at a heating temperature of 800 to 1050 ° C. and a rolling finish temperature of 85.
Rolling is performed under rolling conditions of 0 ° C. or less, and after the rolling is completed, the cooling rate to 500 ° C. is cooled so as to be 0.5 ° C./sec or more to produce a steel having a JIS austenite grain size number of 7 or more. Then, the steel was subjected to a forging heat holding temperature of 1200.
~ 1250 ° C , forging heat holding time 300 seconds or less, and
A method for producing a non-refined, high-strength, high-toughness hot forged part, wherein hot forging is performed at a heating rate of 1 ° C./sec or more to a forging heat holding temperature .
【０００７】（３）重量％で、Ｃ：０．０２〜０．２
％、Ｍｎ：１．０〜３．５％、Ｃｒ：１．０〜３．５
％、Ｖ：０．０１〜０．２％、Ｂ：０．０００３〜０．
００３０％、残部Ｆｅおよび不可避不純物からなる鋼片
を、加熱温度８００〜１０５０℃、圧延仕上温度８５０
℃以下の圧延条件で圧延し、圧延終了後５００℃までの
冷却速度を０．５℃／ｓｅｃ以上となるように冷却し
て、ＪＩＳオーステナイト結晶粒度番号で７番以上の鋼
を製造し、ついでこの鋼を、鍛造加熱保持温度１２００
〜１２５０℃、鍛造加熱保持時間３００秒以下、および
鍛造加熱保持温度までの昇温速度を１℃／ｓｅｃ以上と
して熱間鍛造をおこなうことを特徴とする非調質高強度
高靭性熱間鍛造部品の製造方法。(3) C: 0.02 to 0.2% by weight
%, Mn: 1.0 to 3.5%, Cr: 1.0 to 3.5
%, V: 0.01-0.2%, B: 0.0003-0.
A steel slab consisting of 0030%, balance Fe and unavoidable impurities was heated at a temperature of 800 to 1050 ° C. and a rolling finish temperature of 850.
The steel is rolled under rolling conditions of not more than 0 ° C., and after the end of the rolling, is cooled to a temperature of 500 ° C. so as to have a cooling rate of 0.5 ° C./sec or more. This steel was subjected to a forging heat holding temperature of 1200.
~ 1250 ° C , forging heat holding time 300 seconds or less, and
A method for producing a non-refined, high-strength, high-toughness hot forged part, wherein hot forging is performed at a heating rate of 1 ° C./sec or more to a forging heat holding temperature .
【０００８】（４）重量％で、Ｃ：０．０２〜０．６
％、Ｍｎ：１．０〜３．５％、Ｃｒ：１．０〜３．５
％、Ｖ：０．０１〜０．２％、Ｂ：０．０００３〜０．
００３０％を含み、且つＮｉ≦１．０％、Ｃｕ≦１．０
％、およびＭｏ≦０．５％から選択された１種以上の元
素を含有し、残部Ｆｅおよび不可避不純物からなる鋼片
を、加熱温度８００〜１０５０℃、圧延仕上温度８５０
℃以下の圧延条件で圧延し、圧延終了後５００℃までの
冷却速度を０．５℃／ｓｅｃ以上となるように冷却し
て、ＪＩＳオーステナイト結晶粒度番号で７番以上の鋼
を製造し、ついでこの鋼を、鍛造加熱保持温度１２００
〜１２５０℃、鍛造加熱保持時間３００秒以下、および
鍛造加熱保持温度までの昇温速度を１℃／ｓｅｃ以上と
して熱間鍛造をおこなうことを特徴とする非調質高強度
高靭性熱間鍛造部品の製造方法である。(4) C: 0.02 to 0.6% by weight
%, Mn: 1.0 to 3.5%, Cr: 1.0 to 3.5
%, V: 0.01-0.2%, B: 0.0003-0.
0030%, and Ni ≦ 1.0%, Cu ≦ 1.0
%, And a steel slab containing at least one element selected from Mo ≦ 0.5%, the balance being Fe and unavoidable impurities, at a heating temperature of 800 to 1050 ° C. and a rolling finish temperature of 850.
The steel is rolled under rolling conditions of not more than 0 ° C., and after the end of the rolling, is cooled to a temperature of 500 ° C. so as to have a cooling rate of 0.5 ° C./sec or more. This steel was subjected to a forging heat holding temperature of 1200.
~ 1250 ° C , forging heat holding time 300 seconds or less, and
A method for producing a non-refined, high-strength, high-toughness hot forged part, characterized in that a hot forging is performed at a heating rate of 1 ° C./sec or more to a forging heat holding temperature .
【０００９】[0009]
【作用】以下に本発明における各構成要件の限定理由を
説明する。 （Ａ）まず、圧延および鍛造の条件限定理由を説明す
る。 (1) 圧延加熱温度：圧延加熱温度が1050℃を越えると
オーステナイト結晶粒が粗大化し、圧延後に組織が微細
化しない。また 800℃未満だと変形抵抗が増大するため
800〜1050℃とする。The reasons for limiting each component in the present invention will be described below. (A) First, the reasons for limiting the conditions of rolling and forging will be described. (1) Rolling heating temperature: If the rolling heating temperature exceeds 1050 ° C., austenite crystal grains become coarse and the structure does not become fine after rolling. If the temperature is lower than 800 ° C, the deformation resistance will increase.
It is set to 800 to 1,050 ° C.
【００１０】(2) 圧延仕上り温度：圧延仕上り温度が
850℃を越えると、圧延後の組織が微細化しないため 8
50℃以下とする。 (3) 圧延後の冷却速度：圧延後の冷却速度が 0.5℃/s
ecより遅いと圧延後の組織が微細化しないため 0.5℃/s
ec以上とする。(2) Rolling finish temperature: Rolling finish temperature is
If the temperature exceeds 850 ° C, the microstructure after rolling will not be refined.
50 ° C or less. (3) Cooling rate after rolling: cooling rate after rolling is 0.5 ° C / s
If it is slower than ec, the structure after rolling will not be refined.
ec or more.
【００１１】(4) 圧延後の結晶粒度：圧延後の結晶粒
度が JISオーステナイト結晶粒度番号で７番より大き結
晶粒の場合、その後の熱間鍛造によって組織の粗大化を
生じ、靭性が劣化する。したがって７番以下の細粒とす
る。(4) Grain size after rolling: If the grain size after rolling is larger than 7 in the JIS austenite grain size number, the structure is coarsened by hot forging and the toughness is deteriorated. . Therefore, fine particles of No. 7 or less are used.
【００１２】（５） 鍛造加熱温度：鍛造加熱温度が１
２５０℃を超えると、組織の粗大化を生じ、靭性が劣化
する。また１２００℃未満だと変形抵抗が増大し、金型
寿命が低下する。従って１２００〜１２５０℃とする。(5) Forging heating temperature: Forging heating temperature is 1
If the temperature exceeds 250 ° C., the structure becomes coarse and the toughness deteriorates. On the other hand, when the temperature is lower than 1200 ° C. , the deformation resistance increases, and the life of the mold decreases. Therefore, the temperature is set to 1200 to 1250 ° C.
【００１３】(6) 鍛造加熱保持時間：鍛造加熱保持時
間が 300秒を越えると、組織の粗大化を生じ、靭性が劣
化する。したがって 300秒以下とする。 (7) 鍛造加熱昇温速度：鍛造加熱昇温速度が１℃/sec
未満では組織の粗大化を生じ、靭性が劣化する。したが
って１℃/sec以上とする。(6) Forging heating holding time: If the forging heating holding time exceeds 300 seconds, the structure becomes coarse and the toughness deteriorates. Therefore, it is set to 300 seconds or less. (7) Forging heating rate: The forging heating rate is 1 ° C / sec.
If it is less than 1, the structure becomes coarse, and the toughness deteriorates. Therefore, it is set to 1 ° C./sec or more.
【００１４】（Ｂ）さらに成分を限定することにより一
層の高強度高靭性化をはかることができる。即ち第２発
明における鋼は、機械構造用炭素鋼を対象にしたもので
組織的にはフェライト・パーライトが主体である。また
第３、第４発明における鋼は、構造用合金鋼を対象にし
たもので、組織的にはベイナイトが主体である。フェラ
イト・パーライト主体の組織を有する部品の場合の成分
限定理由を以下に示す。(B) By further limiting the components, higher strength and toughness can be achieved. That is, the steel according to the second invention is intended for carbon steel for machine structural use, and is mainly composed of ferrite / pearlite. The steel in the third and fourth inventions is intended for structural alloy steel, and is mainly composed of bainite. The reasons for limiting the components in the case of parts having a structure mainly composed of ferrite and pearlite are shown below.
【００１５】(1) Ｃ：強度確保のため0.2%以上とし、
0.6%を越えるとパーライト量が増加し靭性が劣化するた
め 0.2〜0.6%とする。 (2) Mn: 強度と共に靭性を増加させる元素である。0.
8%未満では効果が無く、2.0%を越えると偏析が大きくな
り、逆に靭性を劣化させるため 0.8〜2.0%とする。
(3) Ｐ：偏析を生じやすい元素であり、多すぎると靭
性が劣化するため0.015%以下とする。(1) C: 0.2% or more for securing strength;
If it exceeds 0.6%, the pearlite content increases and the toughness deteriorates, so the content is made 0.2 to 0.6%. (2) Mn: an element that increases toughness together with strength. 0.
If it is less than 8%, there is no effect, and if it exceeds 2.0%, segregation becomes large, and conversely, toughness is deteriorated, so that the content is made 0.8 to 2.0%.
(3) P: an element that is likely to cause segregation, and if it is too much, toughness deteriorates, so that the content is made 0.015% or less.
【００１６】(4) Ｎ：Ｖ，Ti，あるいはNbと窒化物を
形成し、組織の微細化に必要な元素である。0.005%未満
では効果が無く、0.02% を越えると窒化物が大きくな
り、組織の微細化に寄与しなくなるため 0.005〜0.02%
とする。(4) N: N is an element necessary to form a nitride with V, Ti, or Nb and to refine the structure. If it is less than 0.005%, there is no effect, and if it exceeds 0.02%, the nitride becomes large and does not contribute to the refinement of the structure, so 0.005 to 0.02%
And
【００１７】(5) Ｖ，Ti、Nb：これらの元素は炭窒化
物を形成し、析出硬化および結晶粒の微細化に効果を示
す元素である。それぞれ0.01%,0.001%,0.005% 未満では
効果がなく、逆に多量に含有させても効果が飽和するた
め、それぞれの上限を、0.2%,0.02%,0.01%とする。した
がってＶは0.01〜0.2%、Tiは 0.001〜0.02、Nbは0.005
〜0.1%とする。(5) V, Ti, Nb: These elements form carbonitrides and are effective for precipitation hardening and grain refinement. If the content is less than 0.01%, 0.001%, and 0.005%, respectively, there is no effect. Conversely, even if a large amount is contained, the effect is saturated. Therefore, the upper limits are set to 0.2%, 0.02%, and 0.01%. Therefore, V is 0.01-0.2%, Ti is 0.001-0.02, and Nb is 0.005%.
To 0.1%.
【００１８】（Ｃ）さらに第３、第４発明におけるベイ
ナイト主体の組織を有する部品の場合の各成分の働きと
成分限定理由を以下に示す。 (1) Ｃ：強度確保のため0.02% 以上とし、0.2%を越え
ると炭化物量が増加し靭性が劣化するため0.02〜0.2%と
する。(C) Further, the function of each component and the reason for limiting the components in the case of the component having a bainite-based structure in the third and fourth aspects of the present invention will be described below. (1) C: 0.02% or more for securing strength, and if 0.2% or more, the amount of carbide increases and toughness deteriorates, so 0.02 to 0.2%.
【００１９】(2) Mn、Cr: 強度と共に靭性を増加させ
る元素である。1.0%未満では効果が無く、3.5%を越える
と効果が飽和すると共にコスト高となるため 1.0〜3.5%
とする。(2) Mn, Cr: elements that increase toughness as well as strength. If it is less than 1.0%, there is no effect, and if it exceeds 3.5%, the effect is saturated and the cost increases, so 1.0 to 3.5%
And
【００２０】(3) Ｖ：強力な強化元素であり、高強度
を得るために重要な元素である。0.01% 未満では効果が
無く、0.2%を越えると靭性が劣化するため0.01〜0.2%と
する。(3) V: a strong strengthening element, an important element for obtaining high strength. If it is less than 0.01%, there is no effect, and if it exceeds 0.2%, the toughness deteriorates, so the content is made 0.01 to 0.2%.
【００２１】(4) Ｂ：焼入性を向上させるため必要な
元素である。0.0003% 未満ではその効果がなく、0.003%
を越えてもその効果が飽和するため0.0003〜0.003%とす
る。 （Ｄ）本発明ではさらにNi、Cu、Moの１種以上を含有さ
せることができる。(4) B: An element necessary for improving hardenability. Less than 0.0003% has no effect, 0.003%
Exceeds 0.0003% because the effect is saturated. (D) In the present invention, one or more of Ni, Cu, and Mo can be further contained.
【００２２】(1) Ni、Cu：これらはいずれも高強度高
靭性を得るための元素であるが、経済的な面を考慮して
1%以下とした。 (2) Mo: 強度、靭性を向上させるのに有効な元素であ
るが、やはり経済的な面を考慮して0.5%以下とした。(1) Ni, Cu: These are elements for obtaining high strength and high toughness, but in consideration of economical aspects.
1% or less. (2) Mo: An element effective for improving strength and toughness, but 0.5% or less in consideration of economical aspects.
【００２３】[0023]
【実施例】本発明の実施例を表１〜表６に示す。表１に
示す化学成分の鋼を用い、表２に示す圧延条件で７０ｍ
ｍΦ棒鋼を製造し、同表の鍛造条件で厚みが１８ｍｍの
板を製造した。表中Ｎｏ．１〜９は圧延条件を変えて丸
棒を製造した後、一定の製造条件にて製造したものであ
り、Ｎｏ．１０〜２０（但し、Ｎｏ．１１は欠番）は一
定の圧延条件にて丸棒を製造した後、鍛造条件を変えて
製造したものである。表中のＮｏ．２〜５、８、１２、
１４〜１６、１９、２０は本発明例であり、Ｎｏ．１，
６，７，９，１０，１３，１７，１８は本発明の条件を
外れた比較例である。本発明例は比較例に比べ靭性が優
れていることがわかる。Ｎｏ．１０鋼は靭性は優れてい
るが鍛造温度が低いため細粒化し強度がやや低く高強度
高靭性の点で劣っており、また金型コストも高い難点が
ある。表３に示す科学成分の鋼を用い、表４に示す圧延
条件で７０ｍｍΦ棒鋼を製造し、道標の鍛造条件で厚み
が１８ｍｍの板を製造した。表中Ｎｏ．１〜７はフェラ
イト・パーライト組織を有する本発明鋼であり、Ｎｏ．
８〜１３は比較鋼である。表３に結果をしめしている
が、本発明鋼は比較例に比べ靭性が優れていることが分
かる。EXAMPLES Examples of the present invention are shown in Tables 1 to 6. Using steel having the chemical composition shown in Table 1, under rolling conditions shown in Table 2, 70 m
An mΦ steel bar was manufactured, and a plate having a thickness of 18 mm was manufactured under the forging conditions shown in the same table. No. in the table. Nos. 1 to 9 are manufactured under constant manufacturing conditions after manufacturing rolling bars under different rolling conditions. Nos. 10 to 20 (however, No. 11 is a missing number) are manufactured by changing a forging condition after manufacturing a round bar under a constant rolling condition. No. in the table. 2-5, 8, 12,
Nos. 14 to 16, 19 and 20 are examples of the present invention. 1,
6, 7, 9, 10, 13, 17, and 18 are comparative examples that deviate from the conditions of the present invention. It can be seen that the examples of the present invention have better toughness than the comparative examples. No. Steel No. 10 is excellent in toughness, but is low in forging temperature, so that it is finely grained and slightly inferior in strength, inferior in high strength and toughness, and has a high mold cost. Using steel having the chemical composition shown in Table 3, a 70 mmΦ steel bar was manufactured under the rolling conditions shown in Table 4, and a plate having a thickness of 18 mm was manufactured under the forging conditions of the signpost. No. in the table. Nos. 1 to 7 are steels of the present invention having a ferrite-pearlite structure.
8 to 13 are comparative steels. The results are shown in Table 3, which shows that the steel of the present invention is superior in toughness as compared with the comparative example.
【００２４】表５に示す化学成分の鋼を用い、表６に示
す圧延条件で60mmφ棒鋼を製造し、同表の鍛造条件で厚
みが18mmの板を製造した。表中No.1〜14はベイナイト組
織を有する本発明鋼であり、 No.15〜17は比較鋼であ
る。表５に結果を示しているが、本発明例は比較例に比
べ靭性が優れていることが分かる。A steel bar having a chemical composition shown in Table 5 was used to produce a 60 mmφ steel bar under the rolling conditions shown in Table 6, and a plate having a thickness of 18 mm was produced under the forging conditions shown in the same table. In the table, Nos. 1 to 14 are steels of the present invention having a bainite structure, and Nos. 15 to 17 are comparative steels. The results are shown in Table 5, and it can be seen that the present invention example is superior in toughness as compared with the comparative example.
【００２５】[0025]
【表１】 [Table 1]
【００２６】[0026]
【表２】 [Table 2]
【００２７】[0027]
【表３】 [Table 3]
【００２８】[0028]
【表４】 [Table 4]
【００２９】[0029]
【表５】 [Table 5]
【００３０】[0030]
【表６】 [Table 6]
【００３１】[0031]
【発明の効果】本発明は圧延した非調質棒鋼を熱間鍛造
部品素材として使用するもので、素材の圧延に際しては
制御圧延、制御冷却をおこなって結晶粒の微細化を図
り、また部品の熱間鍛造に際しては加熱時に急速昇熱・
短時間加熱を行って結晶粒の成長を押さえ、通常と同じ
高い鍛造温度範囲で熱間鍛造できるため、従来より安価
に優れた靭性を有する非調質高強度高靭性熱間鍛造部品
を得るのに効果のある製造方法である。According to the present invention, a rolled non-heat treated steel bar is used as a hot forged part material. In rolling the material, controlled rolling and controlled cooling are performed to reduce the crystal grains, and In hot forging, rapid heating during heating
By heating for a short time to suppress the growth of crystal grains and performing hot forging in the same high forging temperature range as usual, it is possible to obtain non-refined high strength high toughness hot forged parts with excellent toughness at lower cost than before. This is a manufacturing method that is effective for
フロントページの続き (72)発明者 石川 信行 東京都千代田区丸の内一丁目１番２号 日本鋼管株式会社内 (72)発明者 大鈴 弘忠 東京都千代田区五番町６番地２ トー ア・スチール株式会社内 (72)発明者 金丸 武 東京都千代田区五番町６番地２ トー ア・スチール株式会社内 (72)発明者 中野 志郎 東京都千代田区五番町６番地２ トー ア・スチール株式会社内 (56)参考文献 特開 昭64−56821（ＪＰ，Ａ) 特開 昭64−55328（ＪＰ，Ａ) 特開 昭64−52020（ＪＰ，Ａ) 特開 昭64−4423（ＪＰ，Ａ) 特開 平４−228519（ＪＰ，Ａ) 特開 昭63−162810（ＪＰ，Ａ) 特開 平５−230531（ＪＰ，Ａ) 特開 平２−217420（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C21D 8/00 - 8/10 C22C 38/00 - 38/60 Continued on the front page (72) Inventor Nobuyuki Ishikawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Hirotada Osuzu 6-2 Gobancho, Chiyoda-ku, Tokyo Tor Steel Inside (72) Inventor Takeshi Kanamaru 6-2 Gobancho, Chiyoda-ku, Tokyo Tor Steel Co., Ltd. (72) Inventor Shiro Nakano 6-2 Gobancho, Chiyoda-ku, Tokyo Tor Steel Co., Ltd. (56) References JP-A-64-56821 (JP, A) JP-A-64-55328 (JP, A) JP-A-64-52020 (JP, A) JP-A-64-4423 (JP, A) JP-A-4-228519 (JP, A) JP-A-63-162810 (JP, A) JP-A-5-230531 (JP, A) JP-A-2-217420 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) C21D 8/00-8/10 C22C 38/00-38/60
Claims (4)
０〜１０５０℃、圧延仕上り温度８５０℃以下の圧延条
件で圧延し、圧延終了後５００℃までの冷却速度を０．
５℃／ｓｅｃ以上となるように冷却して、ＪＩＳオース
テナイト結晶粒度番号で７番以上の鋼を製造し、ついで
この鋼を、鍛造加熱保持温度１２００〜１２５０℃、鍛
造加熱保持時間３００秒以下、および鍛造加熱保持温度
までの昇温速度を１℃／ｓｅｃ以上として熱間鍛造をお
こなうことを特徴とする非調質高強度高靭性熱間鍛造部
品の製造方法。A non-heat treated steel slab for hot forging is heated to a heating temperature of 80%.
Rolling is performed under rolling conditions of 0 to 1050 ° C. and a rolling finish temperature of 850 ° C. or less, and after the completion of rolling, the cooling rate to 500 ° C. is 0.
5 ° C. and cooled so that / sec or more, to produce a seventh or more steel in JIS austenite grain size number, then the steel, forged heat holding temperature 1,200 to 1,250 ° C., wrought
Non-tempering, high-strength, high-toughness hot forged parts characterized in that hot forging is performed with a forging heat holding time of 300 seconds or less and a heating rate up to a forging heat holding temperature of 1 ° C./sec or more. Manufacturing method.
ｎ：０．８〜２．０％、Ｐ：０．０１５％以下、Ｎ：
０．００５〜０．０２％を含み、且つＶ：０．０１〜
０．２％、Ｔｉ：０．００１〜０．０２％およびＮｂ：
０．００５〜０．１％から選択された１種以上の元素を
含有し、残部Ｆｅおよび不可避不純物からなる鋼片を、
加熱温度８００〜１０５０℃、圧延仕上り温度８５０℃
以下の圧延条件で圧延し、圧延終了後５００℃までの冷
却速度を０．５℃／ｓｅｃ以上となるように冷却して、
ＪＩＳオーステナイト結晶粒度番号で７番以上の鋼を製
造し、ついでこの鋼を、鍛造加熱保持温度１２００〜１
２５０℃、鍛造加熱保持時間３００秒以下、および鍛造
加熱保持温度までの昇温速度を１℃／ｓｅｃ以上として
熱間鍛造をおこなうことを特徴とする非調質高強度高靭
性熱間鍛造部品の製造方法。2. C: 0.2-0.6% by weight, M
n: 0.8 to 2.0%, P: 0.015% or less, N:
0.005 to 0.02%, and V: 0.01 to
0.2%, Ti: 0.001 to 0.02% and Nb:
A steel slab containing at least one element selected from 0.005 to 0.1%, the balance being Fe and unavoidable impurities;
Heating temperature 800-1050 ° C, rolling finish temperature 850 ° C
Rolling is performed under the following rolling conditions, and after the completion of the rolling, the cooling rate to 500 ° C. is cooled so as to be 0.5 ° C./sec or more.
A steel having a JIS austenite grain size number of 7 or more was manufactured, and then this steel was subjected to a forging heat holding temperature of 1200 to 1
250 ° C , forging heat holding time 300 seconds or less, and forging
A method for producing a non-refined, high-strength, high-toughness hot forged part, wherein hot forging is performed at a heating rate of 1 ° C./sec or more to a heating holding temperature .
ｎ：１．０〜３．５％、Ｃｒ：１．０〜３．５％、Ｖ：
０．０１〜０．２％、Ｂ：０．０００３〜０．００３０
％、残部Ｆｅおよび不可避不純物からなる鋼片を、加熱
温度８００〜１０５０℃、圧延仕上温度８５０℃以下の
圧延条件で圧延し、圧延終了後５００℃までの冷却速度
を０．５℃／ｓｅｃ以上となるように冷却して、ＪＩＳ
オーステナイト結晶粒度番号で７番以上の鋼を製造し、
ついでこの鋼を、鍛造加熱保持温度１２００〜１２５０
℃、鍛造加熱保持時間３００秒以下、および鍛造加熱保
持温度までの昇温速度を１℃／ｓｅｃ以上として熱間鍛
造をおこなうことを特徴とする非調質高強度高靭性熱間
鍛造部品の製造方法。3. C: 0.02 to 0.2% by weight, M
n: 1.0 to 3.5%, Cr: 1.0 to 3.5%, V:
0.01-0.2%, B: 0.0003-0.0030
%, The remaining slab consisting of Fe and unavoidable impurities is rolled under rolling conditions of a heating temperature of 800 to 1050 ° C. and a finishing temperature of 850 ° C. Cool to become JIS
Manufacture steel with austenite grain size number 7 or more,
Then, the steel was subjected to a forging heat holding temperature of 1200 to 1250.
℃ , forging heating holding time 300 seconds or less, and forging heating holding
A method for producing a non-refined, high-strength, high-toughness hot forged part, wherein a hot forging is performed at a heating rate up to a holding temperature of 1 ° C./sec or more.
ｎ：１．０〜３．５％、Ｃｒ：１．０〜３．５％、Ｖ：
０．０１〜０．２％、Ｂ：０．０００３〜０．００３０
％を含み、且つＮｉ≦１．０％、Ｃｕ≦１．０％、およ
びＭｏ≦０．５％から選択された１種以上の元素を含有
し、残部Ｆｅおよび不可避不純物からなる鋼片を、加熱
温度８００〜１０５０℃、圧延仕上温度８５０℃以下の
圧延条件で圧延し、圧延終了後５００℃までの冷却速度
を０．５℃／ｓｅｃ以上となるように冷却して、ＪＩＳ
オーステナイト結晶粒度番号で７番以上の鋼を製造し、
ついでこの鋼を、鍛造加熱保持温度１２００〜１２５０
℃、鍛造加熱保持時間３００秒以下、および鍛造加熱保
持温度までの昇温速度を１℃／ｓｅｃ以上として熱間鍛
造をおこなうことを特徴とする非調質高強度高靭性熱間
鍛造部品の製造方法。4. In% by weight, C: 0.02 to 0.6%, M
n: 1.0 to 3.5%, Cr: 1.0 to 3.5%, V:
0.01-0.2%, B: 0.0003-0.0030
%, And one or more elements selected from Ni ≦ 1.0%, Cu ≦ 1.0%, and Mo ≦ 0.5%, and a balance consisting of Fe and unavoidable impurities, Rolling is performed under rolling conditions of a heating temperature of 800 to 1050 ° C. and a rolling finish temperature of 850 ° C., and after the rolling is completed, the cooling rate until 500 ° C. is 0.5 ° C./sec or more.
Manufacture steel with austenite grain size number 7 or more,
Then, the steel was subjected to a forging heat holding temperature of 1200 to 1250.
℃ , forging heating holding time 300 seconds or less, and forging heating holding
A method for producing a non-refined, high-strength, high-toughness hot forged part, wherein a hot forging is performed at a heating rate up to a holding temperature of 1 ° C./sec or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21927594A JP3274028B2 (en) | 1994-08-29 | 1994-09-13 | Manufacturing method of non-heat treated high strength high toughness hot forged parts |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6-203931 | 1994-08-29 | ||
| JP20393194 | 1994-08-29 | ||
| JP21927594A JP3274028B2 (en) | 1994-08-29 | 1994-09-13 | Manufacturing method of non-heat treated high strength high toughness hot forged parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08120342A JPH08120342A (en) | 1996-05-14 |
| JP3274028B2 true JP3274028B2 (en) | 2002-04-15 |
Family
ID=26514182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21927594A Expired - Fee Related JP3274028B2 (en) | 1994-08-29 | 1994-09-13 | Manufacturing method of non-heat treated high strength high toughness hot forged parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3274028B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4884606B2 (en) * | 2001-07-11 | 2012-02-29 | 新日本製鐵株式会社 | Heating method of steel sheet for thermoforming |
| JP3961982B2 (en) | 2002-06-28 | 2007-08-22 | 住友金属工業株式会社 | Non-tempered crankshaft of work machine engine |
-
1994
- 1994-09-13 JP JP21927594A patent/JP3274028B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08120342A (en) | 1996-05-14 |
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