JP3091795B2 - Manufacturing method of steel bars with excellent drawability - Google Patents
Manufacturing method of steel bars with excellent drawabilityInfo
- Publication number
- JP3091795B2 JP3091795B2 JP04167812A JP16781292A JP3091795B2 JP 3091795 B2 JP3091795 B2 JP 3091795B2 JP 04167812 A JP04167812 A JP 04167812A JP 16781292 A JP16781292 A JP 16781292A JP 3091795 B2 JP3091795 B2 JP 3091795B2
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- slab
- molten steel
- steel
- content
- reduction
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Description
【０００１】[0001]
【産業上の利用分野】この発明は、各種機械部品、工具
用材料及び各種機器の軸類等に供する棒鋼の製造方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a steel bar for use in various machine parts, materials for tools, shafts of various devices, and the like.
【０００２】[0002]
【従来の技術】この種の棒鋼は、熱間圧延で得られたビ
レットをミルにて10〜100 mmφの棒鋼に熱間圧延した
後、この棒鋼に引抜き加工を施して８〜95mmφとするこ
とで得られる。この棒鋼の引抜き加工は総減面率が15〜
20％以上となる場合は、２回に分けて引抜きを行うか、
棒鋼に熱処理を施してから引抜くのが通例である。2. Description of the Related Art This type of steel bar is prepared by hot rolling a billet obtained by hot rolling into a steel bar having a diameter of 10 to 100 mm by a mill, and then drawing the steel bar to a diameter of 8 to 95 mm. Is obtained. The total area reduction rate is 15 ~
If it is more than 20%, you can pull it out twice or
It is customary to subject the steel bar to heat treatment and then to pull it out.
【０００３】[0003]
【発明が解決しようとする課題】棒鋼を得る引抜き加工
は総減面率が高くなるほど、棒鋼の中心軸付近を起点と
する割れ、いわゆるシェブロンクラックや破断が生じる
不利がある。従って減面率が高い場合は引抜き加工に先
立つ熱処理や２回の引抜きが不可欠であるが、この熱処
理を要することなく、しかも１パスで引抜きが完了でき
れば、工程数及びエネルギーの減少などが達成され、工
業的規模での製造において極めて有利である。In the drawing process for obtaining a bar, as the total area reduction rate increases, there is a disadvantage that a crack originating near the central axis of the bar, that is, a so-called chevron crack or break occurs. Therefore, when the area reduction rate is high, heat treatment prior to the drawing process or twice drawing is indispensable. However, if this heat treatment is not required and the drawing can be completed in one pass, the number of steps and energy can be reduced. This is extremely advantageous in production on an industrial scale.
【０００４】引抜き加工に先立つ熱処理や２回の引抜き
が要求されるのは、特に引抜き加工中に生じるシェブロ
ンクラックや破断を回避できないためである。このシェ
ブロンクラックや破断は、主に連続鋳造中の凝固時に生
成する鋳片中心部近傍のマクロ及びセミマクロ偏析に起
因するものじある。[0004] Heat treatment prior to drawing and double drawing are required because, in particular, chevron cracks and breaks that occur during drawing cannot be avoided. These chevron cracks and fractures are mainly caused by macro and semi-macro segregation near the center of the slab generated during solidification during continuous casting.
【０００５】かかる中心偏析の防止策として、例えば２
次冷却帯域における電磁攪拌などが試みられたが、セミ
マクロ偏析までを軽減するには至ってなく、その効果は
十分とはいえない。また鋳片の凝固末期に一対のロール
を用いて大圧下を施す、いわゆるインラインリダクショ
ン法｛鉄と鋼 第60年(1974) 第７号 875〜884 頁｝の
適用も試みられたが、この方法では、未凝固層の大きい
鋳片領域における圧下が不十分な場合にはＣ、Mn、Ｐ及
びＳ等の偏析している凝固界面に割れ（以下内部割れと
示す）が発生するという問題があった。As a measure for preventing such center segregation, for example, 2
Attempts have been made to use electromagnetic stirring in the secondary cooling zone, but it has not been able to reduce semi-macro segregation and its effect is not sufficient. Attempts have also been made to apply the so-called in-line reduction method (Iron and Steel, No. 60 (1974) No. 7, pp. 875-884) of applying a large reduction using a pair of rolls at the end of solidification of a slab. However, when the reduction in the slab area where the unsolidified layer is large is insufficient, there is a problem that cracks (hereinafter referred to as internal cracks) are generated at the segregated solidified interface of C, Mn, P, S and the like. Was.
【０００６】その他、特開昭49-121738 号公報には、鋳
片の凝固先端部付近でロール対による軽圧下を施して、
該部分の凝固収縮量を圧下により補償する方法が、また
特開昭52-54623号公報には、鋳造金型を用いて鋳片の凝
固完了点近傍を大圧下する方法がそれぞれ提案されてい
る。[0006] In addition, Japanese Patent Application Laid-Open No. 49-121738 discloses that a light reduction is performed by a pair of rolls in the vicinity of the solidified front end of a slab.
A method of compensating the solidification shrinkage amount of the portion by rolling down, and Japanese Patent Application Laid-Open No. 525462/23 proposes a method of greatly reducing the vicinity of the solidification completion point of a slab using a casting mold. .
【０００７】しかしながらロールによる軽圧下の場合に
は、複数対のロールにより数mm/mの圧下を施したとして
も、ロールピッチ間に生じる凝固収縮やバルジングを十
分に防止することができず、中心偏析の軽減及び内部割
れ防止に対する効果は不十分で、また圧下位置が適切で
なければかえって中心偏析の発生を促す不利があった。
他方、鍛造金型を用いて鋳片の凝固完了点近傍を大圧下
する方法は、インラインリダクション法のようなロール
による大圧下に比べて凝固界面が割れにくく、また負偏
析も極力回避することが可能で、セミマクロ偏析まで改
善できることが明らかになっているものの、依然として
未凝固層の大きい鋳片領域における圧下が不十分だと内
部割れが発生し、また未凝固層の小さい領域を圧下して
もその効果が得られないことから、最適な圧下条件を模
索しているのが現状である。However, in the case of light pressure reduction by rolls, solidification shrinkage and bulging generated between roll pitches cannot be sufficiently prevented even if pressure reduction of several mm / m is performed by a plurality of pairs of rolls. The effect of reducing segregation and preventing internal cracking was insufficient, and there was a disadvantage that the center segregation was promoted if the rolling position was not appropriate.
On the other hand, the method of using a forging die to greatly reduce the vicinity of the solidification completion point of a slab is less likely to crack the solidification interface and to avoid negative segregation as much as possible compared to a large reduction by a roll such as an in-line reduction method. Although it is clear that it is possible and can improve even semi-macro segregation, internal cracking occurs if the reduction is still insufficient in the large slab area of the unsolidified layer, and even if the small area of the unsolidified layer is reduced At present, we are searching for optimal rolling conditions because the effects cannot be obtained.
【０００８】従って鋳片に生成する中心偏析を飛躍的に
改善するまでには至ってなく、偏析部のＣ、Ｐ及びＳ等
の濃度を低下するために溶鋼のＣ濃度の目標値を下げた
り、Ｐ及びＳを0.005 ％未満にしたり、また鋼種や用途
によっては鋳片段階において拡散焼鈍などを施して対処
しているのが実状であり、大幅なコストアップにもなっ
ている。[0008] Therefore, the center segregation generated in the slab has not been drastically improved, and the target value of the C concentration of the molten steel is lowered in order to lower the concentration of C, P, S, etc. in the segregated portion. In practice, P and S are made less than 0.005%, and depending on the type of steel or application, diffusion annealing or the like is performed at the slab stage, and the cost is greatly increased.
【０００９】この発明は、上記の問題を有利に解決する
もので、連続鋳造法を利用する場合であっても、中心偏
析の生成を極力低減し、もって大きな減面率の引抜き加
工を熱処理や２回の引抜きを要することなく実現する方
法について提案することを目的とする。The present invention advantageously solves the above-mentioned problems. Even when a continuous casting method is used, the generation of center segregation is reduced as much as possible, so that a drawing process with a large area reduction can be performed by heat treatment or the like. The purpose is to propose a method that can be realized without the need for two extractions.
【００１０】[0010]
【課題を解決するための手段】すなわちこの発明は、
Ｃ：0.20〜0.8 wt％（以下単に％で示す）、Si：0.01〜
1.0 ％及びMn：0.3 〜2.0 ％を含み、さらにCr：0.05〜
1.0 ％、Ni：0.05〜1.0％、Mo：0.1 〜0.5 ％、Ｖ：0.0
5〜1.0 ％、Ｂ：0.0002〜0.0030％及びTi：0.002 〜0.0
50 ％のいずれか少なくとも１種を含有し、残部はFeお
よび不可避的不純物の組成になる溶鋼を連続鋳造し、そ
の際、鋳片内部溶鋼が凝固を完了するクレータエンド近
傍にて、取鍋中溶鋼のＣ含有量(C0)に対する鋳片軸心部
におけるＣ含有量（Ｃ）の比Ｃ／C0が0.8 〜1.1 となる
成分濃化防止処理を施し、次いで熱間圧延にて棒鋼と
し、その後この棒鋼に、熱処理を施すことなしに、１回
の減面率が20％以上の引抜き加工を施すことを特徴とす
る引抜き加工性に優れた棒鋼の製造方法である。That is, the present invention provides:
C: 0.20 to 0.8 wt% (hereinafter simply indicated as%), Si: 0.01 to
1.0% and Mn: 0.3 to 2.0%, and Cr: 0.05 to
1.0%, Ni: 0.05 to 1.0%, Mo: 0.1 to 0.5%, V: 0.0
5 to 1.0%, B: 0.0002 to 0.0030% and Ti: 0.002 to 0.0
Continuously casts molten steel containing at least one of 50% and the balance of Fe and unavoidable impurities, with the molten steel inside the slab near the crater end where the molten steel completes solidification. An anti-concentration treatment is carried out so that the ratio C / C 0 of the C content (C) in the slab core portion to the C content (C 0 ) of the molten steel is 0.8 to 1.1, and then a bar is formed by hot rolling. A method of manufacturing a steel bar having excellent drawability, wherein the steel bar is subjected to a drawing process with a reduction in area of 20% or more at one time without heat treatment.
【００１１】[0011]
【作用】まず、この発明において溶鋼の成分組成を上記
の範囲に限定した理由について説明する。 Ｃ：0.20〜0.8 ％ Ｃ量は、主に引抜き後の製品強度又は引抜き焼入れ後の
製品の要求強度（表面硬さ、焼入れ有効硬化深さ）によ
り決定されるが、Ｃ濃度が高くなればなるほど引抜き加
工性が低下し、さらにＣが0.8 ％を超えると衝撃値低下
の問題が生じて実用的ではないため、0.8 ％を上限とす
る。一方Ｃが0.20％未満であれば、十分な加工性を確保
できることから、0.20％を下限とした。First, the reason why the composition of molten steel in the present invention is limited to the above range will be described. C: 0.20 to 0.8% The amount of C is determined mainly by the product strength after drawing or the required strength of the product after drawing and quenching (surface hardness, quenching effective hardening depth). If the drawability decreases, and if C exceeds 0.8%, the impact value decreases, which is not practical, so the upper limit is 0.8%. On the other hand, if C is less than 0.20%, sufficient workability can be secured, so the lower limit was made 0.20%.
【００１２】Si：0.01〜1.0 ％ Siは、脱酸剤として少なくとも 0.01 ％は必要とする。
一方SiはＣの活量を上げる作用があり、特に1.0 ％を超
えると脱炭層の生成が顕著となり、焼入性及び疲労強度
の低下を招くため、上限は1.0 ％とした。Si: 0.01 to 1.0% Si requires at least 0.01% as a deoxidizing agent.
On the other hand, Si has the effect of increasing the activity of C. In particular, if it exceeds 1.0%, the formation of a decarburized layer becomes remarkable, and the hardenability and the fatigue strength decrease, so the upper limit was made 1.0%.
【００１３】Mn：0.3 〜2.0 ％ Mnは、Siと同様、脱酸剤として作用するだけでなく、鋼
の脆化をもたらすＳを固定させ、またさらには焼入性を
向上させて強度及び延性を高める上でも有用な成分であ
るが、含有量が 0.3％に満たないとその効果に乏しく、
一方 2.0％を超えると高価となるばかりか熱間圧延後の
制御冷却あるいは加工途中の熱処理工程においてミクロ
マルテンサイトの生成を促し、特に冷間での加工性を害
するので、0.3 〜2.0 ％の範囲で含有するものとした。Mn: 0.3 to 2.0% Mn, like Si, not only acts as a deoxidizing agent, but also fixes S which causes embrittlement of steel, and further enhances hardenability to improve strength and ductility. Although it is a useful ingredient in increasing the content, its effect is poor if the content is less than 0.3%,
On the other hand, if it exceeds 2.0%, it is not only expensive, but also promotes the formation of micro-martensite in the controlled cooling after hot rolling or the heat treatment process during the working, and impairs the workability especially in the cold state. It was assumed to be contained in.
【００１４】Cr：0.05〜1.0 ％ Crは焼入れして使用される場合に焼入れ性を向上するの
に有効な成分であり、また引抜き加工性を低下させるこ
ともないため、0.05％以上の含有とする。一方1.0 ％を
こえると棒鋼の硬化が大きくなって引抜き加工性も低下
するので、1.0％を上限とする。Cr: 0.05 to 1.0% Cr is an effective component for improving the hardenability when used after quenching, and does not lower the drawability, so that the Cr content is 0.05% or more. I do. On the other hand, if the content exceeds 1.0%, the hardening of the steel bar becomes large and the drawing workability also deteriorates. Therefore, the upper limit is set to 1.0%.
【００１５】Mo：0.05〜0.5 ％ Moは焼入れ性を向上するのに有効な成分であり、また冷
間加工時の変形抵抗も増大させないので、0.05％以上を
含有させる。しかし高価な成分であり、0.5 ％をこえる
と変形抵抗も大きくなるので、0.5 ％を上限とする。Mo: 0.05 to 0.5% Mo is an effective component for improving hardenability and does not increase the deformation resistance during cold working. However, it is an expensive component, and if it exceeds 0.5%, the deformation resistance increases, so the upper limit is 0.5%.
【００１６】Ni：0.05〜1.0 ％ 一般に焼入れ後の強度を高めると延性が低下するが、Ni
は焼入れ後の強度向上に寄与するとともに、延性の低下
を防ぐのに有効な成分であり、すなわち0.05％以上の含
有によって絞りは向上する。一方1.0 ％をこえると、上
記の効果は飽和するため、1.0 ％を上限とする。Ni: 0.05 to 1.0% Generally, when the strength after quenching is increased, ductility is reduced.
Is a component that contributes to improving the strength after quenching and is also effective in preventing a decrease in ductility. That is, the content of 0.05% or more improves the drawing. On the other hand, if it exceeds 1.0%, the above effect is saturated, so the upper limit is 1.0%.
【００１７】Ｖ :0.05〜1.0 ％ Ｖは焼入れ性を向上し、かつ炭窒化物を生成して引抜き
後の強度向上に寄与する。この効果を発揮するには0.05
％以上の含有が必要であり、一方1.0 ％をこえると棒鋼
の強度が上昇して引抜き加工性を阻害するため、1.0 ％
を上限とする。V: 0.05% to 1.0% V improves hardenability and forms carbonitride to contribute to improvement in strength after drawing. 0.05 to achieve this effect
% Or more is required. On the other hand, if it exceeds 1.0%, the strength of the steel bar increases, impairing the drawability, so that the content of 1.0%
Is the upper limit.
【００１８】Ｂ：0.0002〜0.0030％ Ｂは、焼入性の向上に有用な成分であるが、含有量が0.
0002％に満たないとその添加効果に乏しく、一方0.0030
％を超えてもその効果は飽和し、それ以上の効果は望め
ないので、0.0002〜0.0030％の範囲で含有させるものと
した。B: 0.0002 to 0.0030% B is a component useful for improving hardenability, but the content is 0.2%.
If it is less than 0002%, its effect is poor, while 0.0030%
%, The effect saturates and no further effect can be expected, so the content was made 0.0002 to 0.0030%.
【００１９】Ti：0.002 〜0.050 ％ Tiは、強脱酸剤であると同時に、結晶粒径を細かくし、
焼入性を制御する作用をもつ。しかしながら含有量が0.
002 ％に満たないとその添加効果に乏しく、一方0.050
％を超えるとその効果は飽和に達するので、0.002 〜0.
050 ％の範囲で含有させるものとした。なお、上記して
成分のほかにも、強度上昇、焼入性の向上または結晶粒
細粒化などを目的として、Nb及びAlなどを必要量添加し
てもよい。また、一般に引抜きのまま又は焼入れを施し
て最終製品で所定の強度とする棒鋼は、その他の品質要
求（例えば製品使用時の靱性及び耐衝撃性等）も含め、
適宜上記の成分組成範囲内で添加量を決定することが好
ましい。Ti: 0.002 to 0.050% Ti is a strong deoxidizing agent and, at the same time, reduces the crystal grain size.
Has the effect of controlling hardenability. However, the content is 0.
If it is less than 002%, its effect is poor, while 0.050%
%, The effect reaches saturation, so 0.002--0.
It was to be contained in the range of 050%. In addition to the above-mentioned components, Nb and Al may be added in required amounts for the purpose of increasing strength, improving hardenability, or reducing crystal grains. In addition, in general, a steel bar that has been drawn or quenched and has a predetermined strength in the final product is subjected to other quality requirements (for example, toughness and impact resistance during product use).
It is preferable to determine the amount of addition within the above component composition range as appropriate.
【００２０】さてこの発明では、上述したような好適成
分組成になる溶鋼の連続鋳造に際し、鋳片の内部溶鋼が
凝固を完了するクレータエンド近傍にて成分濃化防止処
理を施すことによって、取鍋中溶鋼のＣ含有量(C0)に対
する鋳片軸心部におけるＣ含有量（Ｃ）の比Ｃ／C0を0.
8 〜1.1 に制御する。ここに成分濃化防止処理として
は、鍛圧加工がとりわけ有利に適合するけれども、この
発明は、これだけに限るものではなく、Ｃ／C0比を0.8
〜1.1 に制御することができるならば、他の手段であっ
ても良い。According to the present invention, in the continuous casting of molten steel having a preferred composition as described above, the ladle is subjected to a component concentration preventing treatment near the crater end where the internal molten steel of the slab completes solidification. The ratio C / C 0 of the C content (C) in the slab shaft center portion to the C content (C 0 ) of the medium molten steel is set to 0.
Control to 8 to 1.1. Here, as the component concentration prevention treatment, forging processing is particularly advantageously applied, but the present invention is not limited to this, and the C / C 0 ratio is set to 0.8.
Other means may be used as long as they can be controlled to 1.1.
【００２１】以下、上記した鍛圧加工によってＣ／C0比
の制御が可能な理由について説明する。すなわち内部溶
鋼の凝固末期には、Ｃの濃化が進んだ溶鋼がクレータエ
ンド近傍に存在するため、そのまま凝固すれば中心偏析
となるわけであるが、凝固前に鍛圧加工を施すと、かよ
うなＣ濃化溶鋼は上方に押し出される結果、中心部にお
けるＣ濃度はさほど上昇することはない。従って鍛圧加
工の実施時期をＣの濃化程度に応じて調節すれば、鋳片
軸心部におけるＣ含有量を調整できるわけである。The reason why the C / C 0 ratio can be controlled by the above forging process will be described below. That is, in the final stage of solidification of the internal molten steel, since the molten steel in which the concentration of C has progressed is present near the crater end, if it is solidified as it is, central segregation will occur, but if forging is performed before solidification, As a result, the C concentration in the central portion does not increase so much. Therefore, by adjusting the execution time of the forging according to the degree of enrichment of C, the C content in the slab shaft center can be adjusted.
【００２２】ここでＣ／C0比の上限を1.1 としたのは、
1.1 をこえるとシェブロンクラックや破断が発生するた
めである。一方Ｃ／C0比の下限を0.8 としたのは、製品
における引張り強さが低下し、最終製品に使用上の不都
合が生じるためである。これは、鋳片中心部をＣ／C0比
が0.8 未満の負偏析となり、強度保証に必要なＣやMnの
含有量が維持できなくなるからである。Here, the upper limit of the C / C 0 ratio is set to 1.1 because:
If the ratio exceeds 1.1, a chevron crack or break occurs. On the other hand, the reason why the lower limit of the C / C 0 ratio is set to 0.8 is that the tensile strength of the product is reduced and the final product is inconvenient for use. This is because the center of the slab becomes negatively segregated with a C / C 0 ratio of less than 0.8, and the C and Mn contents required for guaranteeing the strength cannot be maintained.
【００２３】従ってこの発明では、鍛圧加工の如き成分
濃化防止処理によって制御すべき鋳片軸心部におけるＣ
／C0比を0.50〜0.95の範囲に限定したのである。なお、
好ましい鍛圧加工法としては、発明者らが先に特開昭60
-82257号公報において開示した連続鍛圧法がある。Therefore, according to the present invention, the C in the slab shaft center to be controlled by the component concentration preventing treatment such as forging processing.
/ A C 0 ratio is of limited to the range of 0.50 to 0.95. In addition,
As a preferred forging method, the inventors first disclosed in
There is a continuous forging method disclosed in JP-A-82257.
【００２４】[0024]
【実施例】表１に示す化学組成になる溶鋼（記号Ａ〜
Ｋ）を400 ×560 mmのモールドで連続鋳造し、引き抜き
中の鋳片に対し、鋳片内部の溶鋼が凝固を完了するクレ
ータエンド近傍にて、鋳片軸心部のＣ／C0比：0.9 〜1.
05を目標として連続的に鍛圧加工を施し、ブルームを製
造した。その後、鋼片ミルによって150 ×150 mmのビレ
ットに熱間圧延した。さらに棒鋼ミルにて26及び32mmφ
の棒鋼に熱間圧延した。その後この棒鋼を、熱処理を施
すことなしに、１回の引抜き加工で22（六角棒径）及び
27mmφの棒鋼とした。EXAMPLES Molten steel having the chemical composition shown in Table 1 (symbols A to A)
K) is continuously cast in a mold of 400 × 560 mm, and the C / C 0 ratio of the core of the slab near the crater end where the molten steel inside the slab completes solidification with respect to the slab during drawing is: 0.9-1.
Bloom was manufactured by continuously forging with a target of 05. Thereafter, it was hot rolled into a billet of 150 × 150 mm by a billet mill. 26 and 32 mmφ in steel bar mill
Hot rolled into steel bars. After that, this steel bar was subjected to 22 (hex.
The bar was made of 27 mmφ.
【００２５】[0025]
【表１】 [Table 1]
【００２６】また従来工程どうり、連続鋳造後、鍛圧加
工を行わずに同様に棒鋼とする加工を行って比較例とし
た。なお出鋼時の溶鋼加熱度はすべて27〜30℃の範囲で
鋳込み、さらに分塊圧延から棒鋼圧延までの熱間圧延温
度は、この発明の実施例及び比較例共に同一温度履歴と
なるよう配慮した。かくして得られた棒鋼について、超
音波探傷法によってシェブロンクラックの有無及び製品
の絞りについて調査した。その結果を表２に示すよう
に、この発明に従って得られた棒鋼におけるシェブロン
クラックの発生は皆無であった。In addition to the conventional process, after continuous casting, a bar was similarly processed without forging, thereby obtaining a comparative example. The degree of heating of molten steel during tapping is all in the range of 27 to 30 ° C, and the hot rolling temperatures from slab rolling to bar rolling are considered to have the same temperature history in both the examples and comparative examples of the present invention. did. The bar thus obtained was examined by ultrasonic flaw detection for the presence or absence of chevron cracks and the reduction of the product. As shown in Table 2, no chevron crack occurred in the steel bars obtained according to the present invention.
【００２７】[0027]
【表２】 [Table 2]
【００２８】[0028]
【発明の効果】かくしてこの発明に従い、連続鋳造時に
成分濃化防止処理を連続的に付与し鋳片軸心部のＣ／C0
比を制御することによってシェブロンクラックの発生を
防止でき、従って大きな減面率の引抜き加工を熱処理を
要することなく実現し得る。As described above, according to the present invention, the component concentration preventing treatment is continuously applied during continuous casting, and the C / C 0 of the slab shaft center is obtained.
By controlling the ratio, generation of chevron cracks can be prevented, and therefore, drawing with a large area reduction can be realized without requiring heat treatment.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ２２Ｃ 38/54 Ｃ２２Ｃ 38/54 (56)参考文献 特開 平２−84237（ＪＰ，Ａ) 特開 平３−199307（ＪＰ，Ａ) 特開 平３−199308（ＪＰ，Ａ) 特開 平３−226337（ＪＰ，Ａ) 特開 平３−281049（ＪＰ，Ａ) 特開 平５−192742（ＪＰ，Ａ) 特開 平５−131292（ＪＰ，Ａ) 特開 平５−177245（ＪＰ，Ａ) 特開 平５−192743（ＪＰ，Ａ) 特開 平５−192736（ＪＰ，Ａ) 特開 平２−260010（ＪＰ，Ａ) 特開 平３−207812（ＪＰ，Ａ) 特開 平３−183739（ＪＰ，Ａ) 特開 平３−122218（ＪＰ，Ａ) 特開 平２−147148（ＪＰ，Ａ) 特開 平１−212720（ＪＰ，Ａ) 特開 昭50−8713（ＪＰ，Ａ) 特開 平５−253644（ＪＰ，Ａ) 特公 昭48−40535（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 11/00 B21C 1/00 B22D 11/128 350 C22C 38/00 301 C22C 38/08 C22C 38/54 ──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. 7 Identification code FI C22C 38/54 C22C 38/54 (56) References JP-A-2-84237 (JP, A) JP-A-3-199307 (JP) JP-A-3-199308 (JP, A) JP-A-3-226337 (JP, A) JP-A-3-281049 (JP, A) JP-A-5-192742 (JP, A) 5-131292 (JP, A) JP-A-5-177245 (JP, A) JP-A-5-192743 (JP, A) JP-A-5-192736 (JP, A) JP-A-2-260010 (JP, A) A) JP-A-3-207812 (JP, A) JP-A-3-183739 (JP, A) JP-A-3-122218 (JP, A) JP-A-2-147148 (JP, A) JP-A-1 JP-A-212720 (JP, A) JP-A-50-8713 (JP, A) JP-A-5-253644 (JP, A) JP, B1) (58) Fields investigated (Int. Cl. 7 , DB name) B22D 11/00 B21C 1/00 B22D 11/128 350 C22C 38/00 301 C22C 38/08 C22C 38/54
Claims (1)
可避的不純物の組成になる溶鋼を連続鋳造し、その際、
鋳片内部溶鋼が凝固を完了するクレータエンド近傍に
て、取鍋中溶鋼のＣ含有量(C0)に対する鋳片軸心部にお
けるＣ含有量（Ｃ）の比Ｃ／C0が0.8 〜1.1 となる成分
濃化防止処理を施し、次いで熱間圧延にて棒鋼とし、そ
の後この棒鋼に、熱処理を施すことなしに、１回の減面
率が20％以上の引抜き加工を施すことを特徴とする引抜
き加工性に優れた棒鋼の製造方法。1. C: 0.20 to 0.8 wt%, Si: 0.01 to 1.0 wt% and Mn: 0.3 to 2.0 wt%, Cr: 0.05 to 1.0 wt%, Ni: 0.05 to 1.0 wt%, Mo: 0.05 to 0.5 wt%, V: 0.05 to 1.0 wt%, B: 0.0002 to 0.0030 wt%, and Ti: 0.002 to 0.050 wt%, and the balance is based on the composition of Fe and unavoidable impurities. Continuous casting of molten steel
In the vicinity of the crater end where the molten steel in the slab completes solidification, the ratio C / C 0 of the C content (C) in the slab axis to the C content (C 0 ) of the molten steel in the ladle is 0.8 to 1.1. It is characterized in that it is subjected to a treatment for preventing the concentration of components and then to a hot-rolled steel bar, and thereafter, the steel bar is subjected to a drawing process with a reduction in area of 20% or more without any heat treatment. A method of manufacturing steel bars with excellent drawability.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04167812A JP3091795B2 (en) | 1991-06-28 | 1992-06-25 | Manufacturing method of steel bars with excellent drawability |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18412191 | 1991-06-28 | ||
| JP3-184121 | 1991-06-28 | ||
| JP04167812A JP3091795B2 (en) | 1991-06-28 | 1992-06-25 | Manufacturing method of steel bars with excellent drawability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05192744A JPH05192744A (en) | 1993-08-03 |
| JP3091795B2 true JP3091795B2 (en) | 2000-09-25 |
Family
ID=26491746
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04167812A Expired - Fee Related JP3091795B2 (en) | 1991-06-28 | 1992-06-25 | Manufacturing method of steel bars with excellent drawability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3091795B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9907336B2 (en) | 2005-03-29 | 2018-03-06 | British American Tobacco (Investments) Limited | Porous carbon materials and smoking articles and smoke filters therefor incorporating such materials |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100436516B1 (en) * | 1999-12-28 | 2004-06-16 | 주식회사 포스코 | Manufacturing method of material for vehicle steering equipment |
| DE202005015611U1 (en) * | 2005-09-30 | 2005-12-29 | Textron Verbindungstechnik Gmbh & Co. Ohg | Bolts or screws with high rigidity are made from steel wire by hot rolling and cooling glowing product by blowing on air, then rolling out and cold-forming to produce head and thread |
| CN110205434B (en) * | 2019-07-12 | 2021-08-06 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for smelting steel bar with low cost |
-
1992
- 1992-06-25 JP JP04167812A patent/JP3091795B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9907336B2 (en) | 2005-03-29 | 2018-03-06 | British American Tobacco (Investments) Limited | Porous carbon materials and smoking articles and smoke filters therefor incorporating such materials |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05192744A (en) | 1993-08-03 |
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