JP2508034B2 - High strength and high toughness hot forging and quenching steel - Google Patents
High strength and high toughness hot forging and quenching steelInfo
- Publication number
- JP2508034B2 JP2508034B2 JP61276737A JP27673786A JP2508034B2 JP 2508034 B2 JP2508034 B2 JP 2508034B2 JP 61276737 A JP61276737 A JP 61276737A JP 27673786 A JP27673786 A JP 27673786A JP 2508034 B2 JP2508034 B2 JP 2508034B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- hot forging
- quenching
- high toughness
- strength
- 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.)
- Expired - Lifetime
Links
Landscapes
- Heat Treatment Of Steel (AREA)
Description
【発明の詳細な説明】 ［発明の目的］ （産業上の利用分野） 本発明は、熱間鍛造によって製作される部品、例えば
ナックルアーム，ナックルスピンドルなどの素材として
利用される高強度高靭性熱間鍛造焼入用鋼に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a high-strength, high-toughness heat used as a material for parts manufactured by hot forging, such as knuckle arms and knuckle spindles. It relates to hot forging and quenching steel.
（従来の技術） 従来、熱間鍛造によって上記に例示した部品を製作す
る場合に、熱間鍛造後に焼入れ・焼もどしの熱処理を施
すことも多い。この熱処理においては、オーステナイ
ト化のための加熱、オーステナイトからの冷却、焼
入れ後の焼もどし、などに代表される工程をとるのが普
通である。(Prior Art) Conventionally, when the above-exemplified parts are manufactured by hot forging, heat treatment such as quenching and tempering is often performed after hot forging. In this heat treatment, it is usual to take steps represented by heating for austenite formation, cooling from austenite, tempering after quenching, and the like.
しかしながら、このような熱処理（調質処理）を行な
う場合には、鍛造品を再加熱するための熱処理炉や、冷
却するための焼入槽および焼もどしを行なうためのテン
パー炉などを必要とすることから、作業工数および設備
費が増大する。However, when such heat treatment (tempering) is performed, a heat treatment furnace for reheating the forged product, a quenching tank for cooling and a tempering furnace for tempering are required. Therefore, the work man-hour and the equipment cost increase.
そこで、上記の調質処理を行なわなくとも高靭性が得
られるように、素材にＶ（バナジウム）を添加すること
も行なわれ、熱間鍛造後に空冷，衝風冷等により冷却す
ることによって非調質で高靭性を得るようにすることも
あった。Therefore, V (vanadium) is also added to the material so that high toughness can be obtained without performing the above-mentioned tempering treatment, and after hot forging, cooling is performed by air cooling, wind blow cooling, etc. In some cases, quality was toughened.
（発明が解決しようとする問題点） しかしながら、Ｖを添加して熱間鍛造後に非調質で高
靭性が得られるようにした場合には、靭性のばらつきを
きたしやすく、品質の安定した鍛造品を得ることができ
ない場合もありうるという問題点があった。(Problems to be Solved by the Invention) However, when V is added so that non-heat treated and high toughness can be obtained after hot forging, the toughness is likely to vary, and the forged product has stable quality. There is a problem that it may not be possible to obtain.
（発明の目的） 本発明はこのような従来の問題点に着目してなされた
もので、熱間鍛造後においてオーステナイト化のための
再加熱および再加熱後の急冷（焼入れ）ならびに焼もど
しの熱処理を行なわずとも、熱間鍛造後に当該熱間鍛造
時の残熱を利用して焼入れすることにより高強度でかつ
高靭性の鍛造品が得られ、その後の焼もどしを省略する
ことが可能である高強度高靭性熱間鍛造焼入用鋼を提供
することを目的としているものである。(Object of the invention) The present invention has been made by paying attention to such conventional problems, and reheating for austenitizing after hot forging and rapid cooling (quenching) and heat treatment for tempering after reheating. Even without performing, forging with high strength and high toughness can be obtained by quenching using the residual heat during hot forging after hot forging, and subsequent tempering can be omitted. It is intended to provide a high strength, high toughness hot forging and quenching steel.
［発明の構成］ （問題点を解決するための手段） 本発明による高強度高靭性熱間鍛造焼入用鋼は、重量
％で、C:0.04〜0.15％、Si:1.0％以下、Mn:0.5〜3.0
％、Cr:0.5〜3.0％、Al:0.01〜0.05％、N:0.006〜0.025
％を含み、必要に応じてMo:0.01〜0.7％,Nb:0.01〜0.1
％のうちから選ばれる１種または２種を含み、同じく必
要に応じてS:0.15％以下,Pb:0.3％以下,Ca:0.005％以
下,Bi:0.3％以下,Te:0.3％以下のうちから選ばれる１種
または２種以上を含み、より望ましくはMn＋Cr:1.5〜4.
0％であり、残部実質的にFeおよび不純物よりなり、熱
間鍛造後Ar3変態点以上で急冷することにより高い靭性
および70％以上の耐力比が得られることを特徴とするも
のである。[Structure of the Invention] (Means for Solving Problems) The high-strength, high-toughness hot forging and quenching steel according to the present invention is, by weight%, C: 0.04 to 0.15%, Si: 1.0% or less, Mn: 0.5-3.0
%, Cr: 0.5 to 3.0%, Al: 0.01 to 0.05%, N: 0.006 to 0.025
%, Mo: 0.01-0.7%, Nb: 0.01-0.1
% Of S: 0.15% or less, Pb: 0.3% or less, Ca: 0.005% or less, Bi: 0.3% or less, Te: 0.3% or less 1 or 2 or more selected from, and more preferably Mn + Cr: 1.5 to 4.
It is 0%, and the balance consists essentially of Fe and impurities, and it is characterized by high toughness and yield strength ratio of 70% or more by quenching after the hot forging at the Ar 3 transformation point or higher.
次に、本発明による高強度高靭性熱間鍛造焼入用鋼の
成分範囲（重量％）の限定理由について説明する。Next, the reason for limiting the component range (% by weight) of the high strength and high toughness hot forging and quenching steel according to the present invention will be described.
C:0.04〜0.15％ Ｃは鍛造品の強度を確保するのに有効な元素であり、
このような効果を得るためには0.04％以上含有させるこ
とが必要である。しかし、多すぎると靭性が低下するの
で0.15％以下とした。C: 0.04 to 0.15% C is an element effective in securing the strength of the forged product,
In order to obtain such effects, it is necessary to contain 0.04% or more. However, if the amount is too large, the toughness decreases, so the content was made 0.15% or less.
Si:1.0％以下 Siは鋼溶製時において脱酸作用を有する元素である
が、多すぎると靭性を低下させるので1.0％以下とし
た。Si: 1.0% or less Si is an element having a deoxidizing effect when steel is melted, but if it is too much, the toughness is reduced.
Mn:0.5〜3.0％ Mnは鋼溶製時において脱酸作用および脱硫作用を有し
ていると共に、介在物の形態を制御し、焼入性を向上さ
せて鍛造品の強度を高めるのに有効な元素であり、この
ような効果を得るためには0.5％以上含有させることが
必要である。しかし、含有量が多すぎると被削性を劣化
させると共に、延性を低下させるので3.0％以下とする
ことが必要である。Mn: 0.5-3.0% Mn has a deoxidizing action and a desulfurizing action during steel melting, and is effective in controlling the form of inclusions and improving hardenability to enhance the strength of forged products. It is an element that does not exist, and it is necessary to contain 0.5% or more to obtain such an effect. However, if the content is too large, the machinability deteriorates and the ductility decreases, so it is necessary to set the content to 3.0% or less.
Cr:0.5〜3.0％ Crは焼入性を向上して鍛造品の強度を高めるのに有効
な元素であり、このような効果を得るためには0.5％以
上含有させることが必要である。しかし、多すぎると強
度が大きくなりすぎ、靭性が低下することとなるので3.
0％以下とする必要がある。Cr: 0.5 to 3.0% Cr is an element effective in improving hardenability and enhancing the strength of the forged product, and it is necessary to contain 0.5% or more to obtain such an effect. However, if it is too large, the strength will be too high and the toughness will decrease, so 3.
It must be 0% or less.
また、強度のより一層の向上ならびに良好な靭性の確
保のためにはMn＋Crで1.5〜4.0％の範囲とすることがよ
り望ましい。Further, in order to further improve the strength and secure good toughness, it is more preferable that the range of Mn + Cr is 1.5 to 4.0%.
Al:0.01〜0.05％ Alは鋼の溶製時において強い脱酸作用を有する元素で
あり、鋼中の酸化物系介在物を減少させて強度を増大さ
せるのに有効であるので、このような効果を得るために
0.01％以上とした。しかし、含有量が多すぎると固溶Ｎ
の量を減少させて、Ｎの添加効果をなくしてしまうので
0.05％以下とすることが必要である。Al: 0.01-0.05% Al is an element that has a strong deoxidizing action during the melting of steel, and is effective in increasing the strength by reducing the oxide inclusions in the steel. To get the effect
It was set to 0.01% or more. However, if the content is too high, solid solution N
Decrease the amount of N and eliminate the effect of N addition.
It should be 0.05% or less.
N:0.006〜0.025％ Ｎは鍛造品の強度を向上させるのに有効な元素であ
り、熱間鍛造後Ar3変態点以上での急冷によって70％以
上の耐力比を確保するのに有効な元素であるので、この
ような効果を得るために0.006％以上とした。しかし、
多すぎるとかえって靭性の低下をもたらすので0.025％
以下とした。N: 0.006 to 0.025% N is an element effective in improving the strength of the forged product, and is an element effective in securing a yield strength ratio of 70% or more by quenching at the Ar 3 transformation point or higher after hot forging. Therefore, in order to obtain such an effect, it is set to 0.006% or more. But,
If it is too large, the toughness will be reduced rather than 0.025%.
Below.
Mo:0.01〜0.7％,Nb:0.01〜0.1％のうちから選ばれる１
種または２種 MoおよびNbはいずれもフェライトの析出を長時間側に
移行させ、焼入性を向上させて強度を高めるのに有効な
元素であるので、このような効果を得るために、Moおよ
びNbのうちから選ばれる１種または２種をMoは0.01％以
上、Nbも0.01％以上必要に応じて含有させるのもよい。
しかし、多量に含有させても添加効果の向上はさほどみ
られず、かえって経済的に不利となるので、添加すると
してもMoは0.7％以下、Nbは0.1％以下とする必要があ
る。1 selected from Mo: 0.01-0.7%, Nb: 0.01-0.1%
Mo and Nb are both effective elements for migrating the precipitation of ferrite to the side for a long time, improving the hardenability, and increasing the strength. One or two selected from Nb and Nb may be contained in 0.01% or more of Mo and 0.01% or more of Nb, if necessary.
However, even if added in a large amount, the effect of addition is not so much improved, which is economically disadvantageous. Therefore, even if added, Mo should be 0.7% or less and Nb should be 0.1% or less.
S:0.15％以下,Pb:0.3％以下,Ca:0.005％以下,Bi:0.3％
以下,Te:0.3％以下のうちから選ばれる１種または２種
以上 S,Pb,Ca,Bi,Teはいずれも被削性を向上させる元素で
あるので、鍛造品において被削性が良好であることが要
求される場合にはこれらのうちから選ばれる１種または
２種以上を適量添加するのもよい。しかしながら、添加
量が多すぎると熱間加工性を低下させたり靭性を劣化さ
せたりするので、添加するとしても、Ｓは0.15％以下、
Pbは0.3％以下、Caは0.005％以下、Biは0.3％以下、Te
は0.3％以下とする必要がある。S: 0.15% or less, Pb: 0.3% or less, Ca: 0.005% or less, Bi: 0.3%
Below, one or more selected from Te: 0.3% or less S, Pb, Ca, Bi, Te are all elements that improve machinability, so machinability is good in forged products. When it is required to be present, one or two or more selected from these may be added in an appropriate amount. However, if the addition amount is too large, the hot workability is deteriorated or the toughness is deteriorated, so even if it is added, S is 0.15% or less,
Pb is 0.3% or less, Ca is 0.005% or less, Bi is 0.3% or less, Te
Should be 0.3% or less.
このような化学成分をもつ本発明による鍛造焼入鋼を
所望の形状に熱間鍛造したのち、この熱間鍛造の際の残
熱を利用し、そして必要に応じて適宜に温度を降下させ
て、Ar3変態点以上（例えば、Ar3＋50℃位）の温度から
急冷して焼入れを行うことによって、高い靭性および70
％以上の耐力比をもつ鍛造品を得ることが可能であり、
焼もどしを必ずしも行わなくとも靭性のすぐれた鍛造品
を非調質で得ることができる。After hot forging the forged and hardened steel according to the present invention having such a chemical composition into a desired shape, the residual heat at the time of this hot forging is utilized, and the temperature is appropriately lowered as necessary. , Ar 3 transformation point or higher (for example, Ar 3 + 50 ℃ or so), quenching by quenching provides high toughness and 70
It is possible to obtain a forged product with a yield strength ratio of
A forged product with excellent toughness can be obtained without tempering without necessarily performing tempering.
（実施例） 第１表に示す本発明鋼（No.1〜７）および比較鋼（N
o.8〜10）を溶製したのち造塊し、各鋼毎に1200℃で0.5
hr加熱保持したあと熱間鍛造を行ない、直径40mmの丸棒
材とし、熱間鍛造後に約900℃以上の温度から水冷によ
り急速冷却した。次いで、各鍛造品より厚さ15mm,幅30m
mの供試材を採取し、各供試材について、降伏点，引張
強さ，耐力比，衝撃値（−50℃,23℃）および硬さ（H
v）を測定した。これらの結果を第２表に示す。(Example) Inventive steels (No. 1 to 7) and comparative steels (N.
o.8 ~ 10) and then ingot, 0.5 for each steel at 1200 ℃
After heat-holding, hot forging was performed to make a round bar with a diameter of 40 mm, and after hot forging, it was rapidly cooled by water cooling from a temperature of about 900 ° C or higher. Next, each forged product is 15 mm thick and 30 m wide
Samples of m were sampled, and for each sample, yield point, tensile strength, proof stress ratio, impact value (-50 ℃, 23 ℃) and hardness (H
v) was measured. Table 2 shows the results.
第１表および第２表より明らかなように、本発明鋼
（No.1〜７）はいずれも非調質の状態において衝撃値が
大で高靭性のものになっているとともに、70％以上の耐
力比が得られていて高強度のものとなっていることが認
められた。 As is clear from Tables 1 and 2, the steels of the present invention (Nos. 1 to 7) all have a high impact value in a non-heat treated state and have high toughness, and at least 70% or more. It was confirmed that the yield strength ratio was obtained and the strength was high.
これに対してＮ量が少ないNo.8の比較鋼では70％以上
の耐力比を得ることができず、またＮ量が多いNo.9の比
較鋼では衝撃値がかなり低く、さらにCr量が少ないNo.1
0の比較鋼では低温での衝撃値がかなり低いものとなっ
ていることが認められた。On the other hand, the comparative steel of No. 8 with a small amount of N cannot obtain a yield strength ratio of 70% or more, and the comparative steel of No. 9 with a large amount of N has a considerably low impact value and further has a Cr content. No.1 less
It was found that the comparative steel of 0 had a considerably low impact value at low temperature.
［発明の効果］ 以上説明してきたように、本発明による高強度高靭性
熱間鍛造焼入用鋼は、重量％で、C:0.04〜0.15％、Si:
1.0％以下、Mn:0.5〜3.0％、Cr:0.5〜3.0％、Al:0.01〜
0.05％、N:0.006〜0.025％を含み、必要に応じてMo:0.0
1〜0.7％,Nb:0.01〜0.1％のうちから選ばれる１種また
は２種を含み、同じく必要に応じてS:0.15％以下,Pb:0.
3％以下,Ca:0.005％以下,Bi:0.3％以下,Te:0.3％以下の
うちから選ばれる１種または２種以上を含み、より望ま
しくはMn＋Cr:1.5〜4.0％であり、残部実質的にFeおよ
び不純物よりなり、熱間鍛造後Ar3変態点以上で急冷す
ることにより高い靭性および70％以上の耐力比が得られ
るものであるから、熱間鍛造後に調質処理を施す必要が
なく、焼入れ時の加熱は熱間鍛造の残熱を利用すること
ができるため、熱間鍛造後に別工程で焼入れを行なう場
合のように焼入れ温度への再加熱を省略することが可能
であると共に、焼入れ後の焼もどし処理をも省略するこ
とが可能であり、非調質で高靭性および耐力比70％以上
の高強度が得られ、かつまた従来のＶ添加鋼のような靭
性のばらつきを生じがたい熱間鍛造焼入用鋼であるとい
う非常に優れた効果がもたらされる。[Advantages of the Invention] As described above, the high-strength, high-toughness hot forging and quenching steel according to the present invention is, by weight%, C: 0.04 to 0.15%, Si:
1.0% or less, Mn: 0.5 to 3.0%, Cr: 0.5 to 3.0%, Al: 0.01 to
0.05%, N: 0.006 to 0.025% included, Mo: 0.0 if necessary
1 to 0.7%, Nb: 0.01 to 0.1%, including one or two selected, and if necessary, S: 0.15% or less, Pb: 0.
3% or less, Ca: 0.005% or less, Bi: 0.3% or less, Te: 0.3% or less, including one or more selected, more preferably Mn + Cr: 1.5 to 4.0%, the balance substantially Is composed of Fe and impurities, and high toughness and yield strength ratio of 70% or more can be obtained by quenching after Ar 3 transformation point after hot forging, so there is no need for heat treatment after hot forging. Since the heating during quenching can utilize the residual heat of hot forging, it is possible to omit reheating to the quenching temperature as in the case of performing quenching in a separate process after hot forging, and It is also possible to omit the tempering treatment after quenching, non-heat treated, high toughness and high strength with a yield strength ratio of 70% or more are obtained, and toughness variation like conventional V-added steel occurs. It has a very excellent effect of being a hard steel for forging and quenching.
Claims (4)
下、Mn:0.5〜3.0％、Cr:0.5〜3.0％、Al:0.01〜0.05
％、N:0.006〜0.025％を含み、残部実質的にFeおよび不
純物よりなり、熱間鍛造後Ar3変態点以上で急冷するこ
とにより高い靭性および70％以上の耐力比が得られるこ
とを特徴とする高強度高靭性熱間鍛造焼入用鋼。1. By weight%, C: 0.04 to 0.15%, Si: 1.0% or less, Mn: 0.5 to 3.0%, Cr: 0.5 to 3.0%, Al: 0.01 to 0.05.
%, N: 0.006 to 0.025%, the balance consists essentially of Fe and impurities, and it is characterized by high toughness and yield strength ratio of 70% or more by quenching after Ar 3 transformation point after hot forging. High strength and high toughness hot forging and quenching steel.
下、Mn:0.5〜3.0％、Cr:0.5〜3.0％、Al:0.01〜0.05
％、N:0.006〜0.025％、およびMo:0.01〜0.7％,Nb:0.01
〜0.1％のうちから選ばれる１種または２種を含み、残
部実質的にFeおよび不純物よりなり、熱間鍛造後Ar3変
態点以上で急冷することにより高い靭性および70％以上
の耐力比が得られることを特徴とする高強度高靭性熱間
鍛造焼入用鋼。2. By weight%, C: 0.04 to 0.15%, Si: 1.0% or less, Mn: 0.5 to 3.0%, Cr: 0.5 to 3.0%, Al: 0.01 to 0.05.
%, N: 0.006-0.025%, and Mo: 0.01-0.7%, Nb: 0.01
0.1% to 0.1%, the balance consists essentially of Fe and impurities, and after hot forging, by quenching at the Ar 3 transformation point or higher, high toughness and yield strength ratio of 70% or more are obtained. High strength and high toughness hot forging and quenching steel characterized by being obtained.
下、Mn:0.5〜3.0％、Cr:0.5〜3.0％、Al:0.01〜0.05
％、N:0.006〜0.025％、およびS:0.15％以下,Pb:0.3％
以下,Ca:0.005％以下,Bi:0.3％以下,Te:0.3％以下のう
ちから選ばれる１種または２種以上を含み、残部実質的
にFeおよび不純物よりなり、熱間鍛造後Ar3変態点以上
で急冷することにより高い靭性および70％以上の耐力比
が得られることを特徴とする高強度高靭性熱間鍛造焼入
用鋼。3. In weight%, C: 0.04 to 0.15%, Si: 1.0% or less, Mn: 0.5 to 3.0%, Cr: 0.5 to 3.0%, Al: 0.01 to 0.05.
%, N: 0.006 to 0.025%, and S: 0.15% or less, Pb: 0.3%
Below, Ca: 0.005% or less, Bi: 0.3% or less, Te: 0.3% or less, including one or more selected, and the balance consisting essentially of Fe and impurities, Ar 3 transformation after hot forging High strength, high toughness hot forging and quenching steel characterized by high toughness and yield strength ratio of 70% or more by quenching above the point.
下、Mn:0.5〜3.0％、Cr:0.5〜3.0％、Al:0.01〜0.05
％、N:0.006〜0.025％、およびMo:0.01〜0.7％,Nb:0.01
〜0.1％のうちから選ばれる１種または２種、さらにS:
0.15％以下,Pb:0.3％以下,Ca:0.005％以下,Bi:0.3％以
下,Te:0.3％以下のうちから選ばれる１種または２種以
上を含み、残部実質的にFeおよび不純物よりなり、熱間
鍛造後Ar3変態点以上で急冷することにより高い靭性お
よび70％以上の耐力比が得られることを特徴とする高強
度高靭性熱間鍛造焼入用鋼。4. By weight%, C: 0.04 to 0.15%, Si: 1.0% or less, Mn: 0.5 to 3.0%, Cr: 0.5 to 3.0%, Al: 0.01 to 0.05.
%, N: 0.006-0.025%, and Mo: 0.01-0.7%, Nb: 0.01
~ 1% or 2 kinds selected from 0.1%, and further S:
0.15% or less, Pb: 0.3% or less, Ca: 0.005% or less, Bi: 0.3% or less, Te: 0.3% or less, including one or more selected, and the balance substantially consisting of Fe and impurities , High strength and high toughness hot forging and quenching steel characterized by high toughness and yield strength ratio of 70% or more obtained by quenching after Ar 3 transformation point after hot forging.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61276737A JP2508034B2 (en) | 1986-11-21 | 1986-11-21 | High strength and high toughness hot forging and quenching steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61276737A JP2508034B2 (en) | 1986-11-21 | 1986-11-21 | High strength and high toughness hot forging and quenching steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63130749A JPS63130749A (en) | 1988-06-02 |
| JP2508034B2 true JP2508034B2 (en) | 1996-06-19 |
Family
ID=17573642
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61276737A Expired - Lifetime JP2508034B2 (en) | 1986-11-21 | 1986-11-21 | High strength and high toughness hot forging and quenching steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2508034B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5079788B2 (en) | 2007-10-29 | 2012-11-21 | 新日本製鐵株式会社 | Non-tempered steel for martensitic hot forging and hot-forged non-tempered steel parts |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5524953A (en) * | 1978-08-11 | 1980-02-22 | Daido Steel Co Ltd | Not thermally refined high strength steel |
| JPS5983719A (en) * | 1982-11-02 | 1984-05-15 | Nippon Steel Corp | Preparation of unnormalized high strength steel |
| JPH0772323B2 (en) * | 1985-04-15 | 1995-08-02 | 株式会社神戸製鋼所 | Non-heat treated steel bar for hot forging |
-
1986
- 1986-11-21 JP JP61276737A patent/JP2508034B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63130749A (en) | 1988-06-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3358135B2 (en) | High strength steel excellent in sulfide stress cracking resistance and method of manufacturing the same | |
| JPH0748621A (en) | Production of steel for pressure vessel excellent in ssc resistance and hic resistance | |
| JPH0772323B2 (en) | Non-heat treated steel bar for hot forging | |
| JPS6223929A (en) | Manufacture of steel for cold forging | |
| JPH01242761A (en) | Ultra high strength steel having low yield ratio and its manufacture | |
| JP2508034B2 (en) | High strength and high toughness hot forging and quenching steel | |
| JPS60121228A (en) | Manufacture of tempered high tension steel plate | |
| JP3814710B2 (en) | Manufacturing method of steel material for high strength cold forming non-tempered buffer / restoration mechanism member | |
| JPS63166949A (en) | Non-heattreated steel for hot forging | |
| JP3620099B2 (en) | Method for producing Cr-Mo steel excellent in strength and toughness | |
| JPS6130653A (en) | High strength spring steel | |
| JPS613833A (en) | Manufacture of high strength steel with superior weldability | |
| JP2593857B2 (en) | High strength non-heat treated forged tough steel | |
| JP2926856B2 (en) | Non-tempered free-cutting steel with excellent hot ductility | |
| JPH0454725B2 (en) | ||
| JP2546888B2 (en) | Manufacturing method of high-strength steel sheet with excellent weldability and toughness | |
| JP2929835B2 (en) | High-strength non-heat treated steel with excellent hot ductility | |
| JPH09125141A (en) | Production of high strength and high corrosion resistant martensitic stainless steel | |
| JPH0229727B2 (en) | DORIRUKARAAYOBOKONOSEIZOHOHO | |
| JPS6148557A (en) | Machine structural steel | |
| JPS62260042A (en) | High strength unrefined tough steel | |
| JPH05339674A (en) | Low carbon 0.5% mo steel sheet excellent in weld crack resistance | |
| JPH07118741A (en) | Production of extremely thick refined high strength steel plate | |
| JP2701438B2 (en) | Manufacturing method of non-tempered free-cutting forged steel with high hot ductility | |
| JPH05339637A (en) | Production of steel pipe or square pipe having low yield ratio and excellent weatherability |