JPH04279246A - Continuously cast billet with sound inner quality - Google Patents
Continuously cast billet with sound inner qualityInfo
- Publication number
- JPH04279246A JPH04279246A JP4024691A JP4024691A JPH04279246A JP H04279246 A JPH04279246 A JP H04279246A JP 4024691 A JP4024691 A JP 4024691A JP 4024691 A JP4024691 A JP 4024691A JP H04279246 A JPH04279246 A JP H04279246A
- Authority
- JP
- Japan
- Prior art keywords
- less
- continuously cast
- present
- cracking
- content
- 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.)
- Withdrawn
Links
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 11
- 239000010959 steel Substances 0.000 claims abstract description 11
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 claims description 13
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 238000001816 cooling Methods 0.000 description 20
- 238000005336 cracking Methods 0.000 description 19
- 238000009749 continuous casting Methods 0.000 description 10
- 238000005266 casting Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 230000008646 thermal stress Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000009849 vacuum degassing Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、内部品質が健全な連続
鋳造丸鋳片に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously cast round slab having a sound internal quality.
【０００２】0002
【従来の技術】連続鋳造に際しては、鋳造・凝固後の冷
却段階においても、その内部および外部に多くの割れが
見られることがあり、前記割れを防止して、内部品質が
健全な鋳片を得るためにこれまでも多くの努力が払われ
ている。例えば、連続鋳造後に鋳片を冷却する場合、表
面割れや内部割れを防止するため、できるだけ熱的衝撃
を与えないように冷却を遅らせることが一般的に行われ
ている。特に、鋳片が小型である場合にはその断面を丸
くすることによって、表面割れをかなり低減することが
できるが、例えば直径が４００ｍｍ 以上といったよう
に大型の場合には冷却を遅らせることにより対応するこ
とが多い。かかる冷却には、約１５日間も要することも
珍しくない。[Prior Art] During continuous casting, many cracks may be observed inside and outside the casting even during the cooling stage after casting and solidification. Many efforts have been made to achieve this. For example, when cooling a slab after continuous casting, cooling is generally delayed to avoid thermal shock as much as possible in order to prevent surface cracks and internal cracks. In particular, if the slab is small, surface cracking can be significantly reduced by rounding its cross section, but if the slab is large, for example with a diameter of 400 mm or more, cooling should be delayed. There are many things. It is not uncommon for such cooling to take as long as about 15 days.
【０００３】しかし、このように冷却を遅らせることは
、連続鋳造を行って鋳片を製造したメリットを著しく低
下させ、製造コストの上昇をもたらすものであるため、
従来から、冷却工程の短縮化・簡略化が強く求められて
いた。そこで、本出願人は、先に特開平２−１９７３５
０号公報により、重量％ （以下、本明細書においては
、特にことわりがない限り、「％」は「重量％」を意味
するものとする） で、Ｃ：０．２０〜０．８０％、
Ｓｉ：０．１０〜０．４０％、 Ｍｎ：０
．５０〜１．００％、Ｐ：０．０３０ ％以下、
Ｓ：０．０３０ ％以下、 Ｃｒ：１．２０％
以下、Ｍｏ：０．３０％以下、 ｓｏｌ．Ａｌ：０．
００５ 〜０．１００ ％、Ｎ：０．０１００％以下、
残部Ｆｅおよび不可避的不純物から成る鋼組成を有する
溶鋼に、Ｏ≦０．００４０％以下、Ｈ≦０．００１０％
以下となるまでの真空脱ガス処理を行ってから連続鋳造
を行って直径４００ 〜４６０ｍｍ 丸鋳片に鋳造後、
７００ 〜２００ ℃の温度範囲を０．０５〜１．３
℃／分の冷却速度で冷却し、内部品質の健全な鋳片を得
る技術を提案した。[0003] However, delaying cooling in this manner significantly reduces the merits of producing slabs by continuous casting and increases production costs.
There has been a strong demand for shortening and simplifying the cooling process. Therefore, the present applicant has previously proposed
According to Publication No. 0, C: 0.20 to 0.80% by weight (hereinafter, in this specification, "%" means "weight %" unless otherwise specified),
Si: 0.10-0.40%, Mn: 0
．． 50-1.00%, P: 0.030% or less,
S: 0.030% or less, Cr: 1.20%
Hereinafter, Mo: 0.30% or less, sol. Al: 0.
005 to 0.100%, N: 0.0100% or less,
O≦0.0040% or less, H≦0.0010% in molten steel having a steel composition consisting of the balance Fe and unavoidable impurities.
After performing vacuum degassing treatment until the following is achieved, continuous casting is performed to form a round slab with a diameter of 400 to 460 mm,
700-200℃ temperature range 0.05-1.3
We proposed a technology to obtain slabs with sound internal quality by cooling at a cooling rate of ℃/min.
【０００４】0004
【発明が解決しようとする課題】この特開平２−１９７
３５０号公報により提案された技術は、連続鋳造を行う
前の水素量を限定することにより水素割れを防止し、か
つ連続鋳造後の冷却速度を限定することにより熱応力割
れの発生を防止している。しかし、本発明者らの知見に
よれば、前記特開平２−１９７３５０号公報により提案
された技術によっても、完全に連続鋳造鋳片に生じる割
れを防止することはできない。例えば、直径が４１０ｍ
ｍ または４５０ｍｍ の連続鋳造丸鋳片を製造すると
、前記連続鋳造丸鋳片を二次冷却あるいは鋳片支持ロー
ルでの引抜き中に前記連続鋳造丸鋳片が冷却されて表面
近傍の外殻が殆ど膨張・収縮不能になった後に、１／２
Ｒ部が収縮する際に発生する熱応力割れと考えられる「
１／２Ｒ割れ」が多発してしまう。[Problem to be solved by the invention] This Japanese Patent Application Laid-Open No. 2-197
The technology proposed in Publication No. 350 prevents hydrogen cracking by limiting the amount of hydrogen before continuous casting, and prevents the occurrence of thermal stress cracking by limiting the cooling rate after continuous casting. There is. However, according to the findings of the present inventors, even the technique proposed in Japanese Patent Application Laid-Open No. 2-197350 cannot completely prevent cracks from occurring in continuously cast slabs. For example, if the diameter is 410m
When producing a continuously cast round slab with a diameter of 450 mm, the continuous cast round slab is cooled during secondary cooling or drawing with slab support rolls, and most of the outer shell near the surface of the continuous cast round slab is cooled. After becoming unable to expand and deflate, 1/2
This is thought to be a thermal stress crack that occurs when the R section contracts.
1/2R cracking occurs frequently.
【０００５】したがって、従来の技術では、かかる１／
２Ｒ割れの発生を回避することはできず、成品の品質管
理を十分に行う必要があり、製造コストの増加、歩留り
の低下等の生産性を低下させる深刻な問題を引き起こし
ていた。ここに、本発明の目的は、前記従来の技術の有
する問題を解消し、１／２Ｒ割れの発生がなく、内部品
質が健全な連続鋳造丸鋳片を提供することにある。[0005] Therefore, in the conventional technology, such 1/
The occurrence of 2R cracking cannot be avoided, and it is necessary to adequately control the quality of the finished product, causing serious problems that reduce productivity such as increased manufacturing costs and decreased yield. SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional techniques and to provide a continuously cast round slab that is free from 1/2R cracking and has a sound internal quality.
【０００６】[0006]
【課題を解決するための手段】本発明者らは、上記課題
を解決するため種々検討を重ねた結果、連続鋳造丸鋳片
の凝固時の内部割れの発生要因であるＮ含有量を６０ｐ
ｐｍ 以下とするとともに、Ｈ含有量も４ｐｐｍ 以下
に限定することにより、鋳込後の冷却速度を限定するこ
となく、上記課題を解決することができることを知り、
本発明を完成した。[Means for Solving the Problems] As a result of various studies in order to solve the above problems, the present inventors have determined that the N content, which is a cause of internal cracking during solidification of continuously cast round slabs, has been reduced to 60p.
pm or less, and by limiting the H content to 4 ppm or less, we learned that the above problems can be solved without limiting the cooling rate after casting,
The invention has been completed.
【０００７】ここに、本発明の要旨とするところは、Ｃ
：０．２０〜０．８０％、 Ｓｉ：０．１０〜０
．４０％、 Ｍｎ：０．５０〜１．００％、Ｐ：
０．０３０ ％以下、 Ｓ：０．０３０ ％以下
、 Ｃｒ：１．２０％以下、Ｍｏ：０．３０％以
下、 ｓｏｌ．Ａｌ：０．００５ 〜０．１００ ％
、Ｎ：６０ｐｐｍ 以下、Ｈ：４ｐｐｍ 以下、残部Ｆ
ｅおよび不可避的不純物から成る鋼組成を有し、直径が
４００ｍｍ 以上である内部品質が健全な連続鋳造丸鋳
片である。[0007] Here, the gist of the present invention is that C
:0.20~0.80%, Si:0.10~0
．． 40%, Mn: 0.50-1.00%, P:
0.030% or less, S: 0.030% or less, Cr: 1.20% or less, Mo: 0.30% or less, sol. Al: 0.005 to 0.100%
, N: 60ppm or less, H: 4ppm or less, balance F
This is a continuously cast round slab with a diameter of 400 mm or more and of sound internal quality, having a steel composition consisting of E and unavoidable impurities.
【０００８】[0008]
【作用】以下、本発明を作用効果とともに詳述する。ま
ず、本発明にかかる連続鋳造丸鋳片の組成を前述の如く
限定する理由を説明する。[Function] The present invention will be explained in detail below along with its functions and effects. First, the reason why the composition of the continuously cast round slab according to the present invention is limited as described above will be explained.
【０００９】Ｃ：０．２０〜０．８０％Ｃ含有量が０．
２０％未満であると内部割れが発生し易くなり、一方０
．８０％超であると、冷却速度の影響が顕著になって割
れ発生防止効果が少なくなる。そこで、本発明において
、Ｃ含有量は０．２０％以上０．８０％以下と限定する
。C: 0.20-0.80% C content is 0.
If it is less than 20%, internal cracks are likely to occur;
．． If it exceeds 80%, the influence of the cooling rate becomes significant and the effect of preventing crack generation decreases. Therefore, in the present invention, the C content is limited to 0.20% or more and 0.80% or less.
【００１０】Ｓｉ：０．１０〜０．４０％Ｓｉ含有量が
０．１０％未満では安定した脱酸を行うことができなく
なり、一方０．４０％超では熱間加工性が劣る。
そこで、本発明においては、Ｓｉ含有量は０．１０％以
上０．４０％以下と限定する。Si: 0.10-0.40% If the Si content is less than 0.10%, stable deoxidation cannot be performed, while if it exceeds 0.40%, hot workability is poor. Therefore, in the present invention, the Si content is limited to 0.10% or more and 0.40% or less.
【００１１】Ｍｎ：０．５０〜１．００％Ｍｎ含有量が
０．５０％未満では熱間加工性が劣り、一方１．００％
超では強度が必要レベル以上となりコスト高となる。
そこで、本発明においては、Ｍｎ含有量は０．５０％以
上１．００％以下と限定する。Mn: 0.50-1.00% If the Mn content is less than 0.50%, hot workability is poor;
In case of super strength, the strength will exceed the required level and the cost will be high. Therefore, in the present invention, the Mn content is limited to 0.50% or more and 1.00% or less.
【００１２】Ｐ、Ｓ：０．０３０ ％以下Ｐ、Ｓは、と
もに熱間加工性を確保するために、また内部割れを防止
するためにも、本発明においてはそれぞれ０．０３０
％以下に限定する。P, S: 0.030% or less P and S are each 0.030% in the present invention in order to ensure hot workability and to prevent internal cracks.
% or less.
【００１３】Ｃｒ：１．２０％以下
Ｃｒは、耐食性および強度の向上を図るために添加され
るが、１．２０％超の添加は連続鋳造丸鋳片の用途上必
要としない。そこで、本発明においては、Ｃｒ含有量は
１．２０％以下と限定する。Cr: 1.20% or less Cr is added to improve corrosion resistance and strength, but addition of more than 1.20% is not necessary for continuous casting round slabs. Therefore, in the present invention, the Cr content is limited to 1.20% or less.
【００１４】Ｍｏ：０．３０％以下
Ｍｏは、強度を改善するために添加するが、０．３０％
超は連続鋳造丸鋳片の用途上必要でない。そこで、本発
明においては、Ｍｏ含有量は０．３０％以下と限定する
。Mo: 0.30% or less Mo is added to improve strength, but 0.30%
Ultra-thickness is not necessary for the purpose of continuous casting round slabs. Therefore, in the present invention, the Mo content is limited to 0.30% or less.
【００１５】ｓｏｌ．Ａｌ：０．００５ 〜０．１００
％ｓｏｌ．Ａｌ含有量が０．００５ ％未満では脱酸
が不足し、一方０．１００ ％超は、表面割れ、内部割
れの防止の観点から好ましくない。さらに、過剰に添加
されると、アルミナ系の介在物が増加し、溶鋼の清浄度
を損なう。そこで、本発明においては、ｓｏｌ．Ａｌ含
有量は、０．００５ ％以上０．１００ ％以下と限定
する。[0015] sol. Al: 0.005 ~ 0.100
%sol. If the Al content is less than 0.005%, deoxidation will be insufficient, while if it exceeds 0.100%, it is not preferable from the viewpoint of preventing surface cracks and internal cracks. Furthermore, when added in excess, alumina-based inclusions increase, impairing the cleanliness of molten steel. Therefore, in the present invention, sol. The Al content is limited to 0.005% or more and 0.100% or less.
【００１６】Ｎ：６０ｐｐｍ 以下
Ｎ含有量が６０ｐｐｍ 超であると、ＡｌＮ等の窒化物
がγ結晶粒界に析出し、凝固時の熱応力により１／２Ｒ
割れを発生してしまう。そこで、本発明においては、Ｎ
含有量は、６０ｐｐｍ 以下と限定する。N: 60 ppm or less If the N content exceeds 60 ppm, nitrides such as AlN will precipitate at the γ grain boundaries, and thermal stress during solidification will cause 1/2R
Cracks will occur. Therefore, in the present invention, N
The content is limited to 60 ppm or less.
【００１７】Ｈ：４ｐｐｍ 以下
Ｈ含有量が４ｐｐｍ 超であると、鋼中のＨが高温時に
拡散し、γ結晶粒界またはボイド部に偏析あるいは析出
し、やはり凝固時の熱応力により１／２Ｒ割れを発生し
てしまう。そこで、本発明においては、Ｈ含有量は、４
ｐｐｍ以下と限定する。H: 4 ppm or less If the H content exceeds 4 ppm, H in the steel will diffuse at high temperatures and will segregate or precipitate at the γ grain boundaries or voids, resulting in 1/2 R due to thermal stress during solidification. Cracks will occur. Therefore, in the present invention, the H content is 4
Limited to ppm or less.
【００１８】Ｏ：４０ｐｐｍ 以下
Ｏ２は、１／２Ｒ割れには直接的には影響を与えないが
、ＡｌＮの析出に対する作用および清浄度の観点から、
４０ｐｐｍ 以下と限定することが好ましい。上記以外
の残部は、Ｆｅおよび不可避的不純物である。O: 40 ppm or less O2 does not directly affect 1/2R cracking, but from the viewpoint of action on AlN precipitation and cleanliness,
It is preferable to limit it to 40 ppm or less. The remainder other than the above is Fe and unavoidable impurities.
【００１９】次に、前記組成を有する連続鋳造丸鋳片は
、その直径が４００ｍｍ 以上である。直径が４００ｍ
ｍ 未満では、前記組成をどのように変化させても１／
２Ｒ割れの発生を回避できないからである。このような
観点からは、直径の上限は特に設ける必要はないが、現
在製造している連続鋳造丸鋳片の最大直径は４６０ｍｍ
程度である。Next, the continuously cast round slab having the above composition has a diameter of 400 mm or more. Diameter is 400m
m, no matter how the composition is changed, 1/
This is because the occurrence of 2R cracking cannot be avoided. From this point of view, there is no need to set an upper limit on the diameter, but the maximum diameter of continuously cast round slabs currently manufactured is 460 mm.
That's about it.
【００２０】なお、本発明にかかる連続鋳造丸鋳片は、
例えば、真空脱ガス処理を行うことにより脱Ｈおよび脱
Ｎを図った前記組成を有する溶鋼を連続鋳造して、直径
が４００ｍｍ 以上の連続鋳造丸鋳片とすることにより
、得られる。[0020] The continuously cast round slab according to the present invention is
For example, it can be obtained by continuously casting molten steel having the above-mentioned composition, which has been subjected to vacuum degassing treatment to remove H and N, to form a continuously cast round slab having a diameter of 400 mm or more.
【００２１】鋳込後の冷却速度は、本発明においては、
何ら限定を要するものではない。例えば、本発明によれ
ば、この冷却速度は、０．３ 〜１．０ ℃／ｍｉｎ
程度を例示することができる。したがって、従来のよう
に、冷却に長期間を要することもない。以上説明した範
囲の組成および直径を有する連続鋳造丸鋳片は、１／２
Ｒ割れの発生がなく、内部品質が健全である。したがっ
て、成品の品質管理が従来よりも容易となり、製造コス
トの低減、歩留りの向上等の生産性の向上を図ることが
可能となる。さらに、本発明を実施例とともに詳述する
が、これはあくまでも本発明の例示であって、これによ
り本発明が限定されるものではない。[0021] In the present invention, the cooling rate after casting is as follows:
There is no need for any limitation. For example, according to the invention, this cooling rate is 0.3 to 1.0 °C/min
The degree can be exemplified. Therefore, there is no need for a long period of time for cooling as in the conventional case. Continuously cast round slabs having the composition and diameter within the range explained above are 1/2
There is no R cracking and the internal quality is sound. Therefore, quality control of finished products becomes easier than before, and it becomes possible to improve productivity such as reducing manufacturing costs and improving yield. Further, the present invention will be described in detail along with Examples, but these are merely illustrative of the present invention and are not intended to limit the present invention.
【００２２】[0022]
【実施例１】表１に示す範囲の組成を有する種々の溶鋼
に連続鋳造を行って直径が４１０ｍｍ の連続鋳造丸鋳
片とし、３５０ 〜４５０ ℃／ｍｉｎ の冷却速度で
常温まで冷却した。この際の湯面変動は最大で１．０〜
５．０ｍｍ の範囲であり、ΔＴ （タンディッシュ内
溶鋼過熱度） は１０〜４５℃の範囲であった。[Example 1] Various molten steels having compositions in the range shown in Table 1 were continuously cast to obtain continuously cast round slabs having a diameter of 410 mm, and cooled to room temperature at a cooling rate of 350 to 450° C./min. The maximum fluctuation in the hot water level at this time is 1.0~
5.0 mm, and ΔT (degree of superheating of molten steel in the tundish) was in the range of 10 to 45°C.
【００２３】[0023]
【表１】[Table 1]
【００２４】このようにして得た連続鋳造丸鋳片の１／
２Ｒ割れの発生の有無を目視により確認した。結果を図
１にグラフで示す。図１から明らかなように、本発明の
組成範囲を満足する連続鋳造丸鋳片は、１／２Ｒ割れが
発生しないことがわかる。1/2 of the continuous cast round slab thus obtained
The presence or absence of 2R cracking was visually confirmed. The results are shown graphically in Figure 1. As is clear from FIG. 1, 1/2R cracking does not occur in continuously cast round slabs that satisfy the composition range of the present invention.
【００２５】[0025]
【実施例２】表２に示す組成を有する溶鋼に連続鋳造を
行って直径が４１０ ｍｍの連続鋳造丸鋳片とし、３５
０ 〜４５０ ℃／ｍｉｎ の冷却速度で常温まで冷却
して、試料Ｎｏ．１ないし試料Ｎｏ．１９ を得た。こ
の際の湯面変動は最大で１．０ 〜５．０ｍｍ の範囲
であり、ΔＴは１０〜４５℃の範囲であった。[Example 2] Molten steel having the composition shown in Table 2 was continuously cast to obtain a continuously cast round slab with a diameter of 410 mm.
Sample No. 1 was cooled to room temperature at a cooling rate of 0 to 450°C/min. 1 to sample no. I got 19. At this time, the maximum temperature fluctuation was in the range of 1.0 to 5.0 mm, and ΔT was in the range of 10 to 45°C.
【００２６】[0026]
【表２】[Table 2]
【００２７】これらの試料について、１／２Ｒ割れの有
無を目視により確認した。その結果、本発明の範囲の組
成を有する試料Ｎｏ．１ないし試料Ｎｏ．１１ は、１
／２Ｒ割れを全く発生しなかった。These samples were visually checked for the presence or absence of 1/2R cracks. As a result, sample No. 1 having a composition within the range of the present invention was found. 1 to sample no. 11 is 1
/2R cracking did not occur at all.
【００２８】一方、試料Ｎｏ．１２ ないし試料Ｎｏ．
１５ は、Ｎ含有量が本発明の範囲の上限を超えている
ため、１／２Ｒ割れを発生した。試料Ｎｏ．１６ ない
し試料Ｎｏ．１９ は、Ｈ含有量が本発明の範囲の上限
を超えているため、やはり１／２Ｒ割れを発生してしま
った。このように、本実施例によっても本発明の効果が
明らかである。On the other hand, sample No. 12 or sample no.
In No. 15, 1/2R cracking occurred because the N content exceeded the upper limit of the range of the present invention. Sample No. 16 or sample no. In No. 19, since the H content exceeded the upper limit of the range of the present invention, 1/2R cracking also occurred. In this way, the effects of the present invention are clear from this example as well.
【００２９】[0029]
【実施例３】従来、平均で、Ｃ：０．６２〜０．６６％
、 Ｓｉ：０．２５〜０．３５％、 Ｍｎ
：０．７０〜０．８５％、Ｐ：０．０１５ 〜０．０１
８ ％、Ｓ：０．００６ 〜０．００８ ％、Ｃｒ：０
．０５％以下、Ｍｏ：０．０５％以下、 ｓｏｌ．Ａ
ｌ：０．０１０ 〜０．０３０ ％、Ｎ：３０〜１００
ｐｐｍ、Ｈ：１０ｐｐｍ 、残部Ｆｅおよび不可避的不
純物という組成を有する連続鋳造丸鋳片 （直径４１０
ｍｍ 、４５０ｍｍ ） を、前記組成を有する溶湯を
連続鋳造して連続鋳造丸鋳片としてから、０．１ ℃／
ｍｉｎ の冷却速度で常温まで冷却することにより、製
造していた工程で、連続鋳造を行う前に溶湯にＲＨ真空
脱ガス処理を行い、平均で、Ｈ：１．１ｐｐｍ、Ｎ：４
．０ｐｐｍに低減してから連続鋳造を行った （本発明
法） 。[Example 3] Conventionally, on average, C: 0.62 to 0.66%
, Si: 0.25-0.35%, Mn
:0.70~0.85%, P:0.015~0.01
8%, S: 0.006 to 0.008%, Cr: 0
．． 05% or less, Mo: 0.05% or less, sol. A
l: 0.010 to 0.030%, N: 30 to 100
ppm, H: 10 ppm, balance Fe and inevitable impurities (diameter 410
mm, 450 mm) was continuously cast into a continuously cast round slab by continuous casting of the molten metal having the above composition, and then cast at 0.1 °C/
By cooling to room temperature at a cooling rate of
．． Continuous casting was performed after reducing the content to 0 ppm (method of the present invention).
【００３０】前記本発明法により、一ヵ月間連続して操
業を行い、１／２Ｒ割れの発生率の変化を調査した。そ
の結果、従来１／２Ｒ割れの発生率は約３．６ ％であ
ったが、本発明により０％に解消することができた。The method of the present invention was operated continuously for one month, and changes in the incidence of 1/2R cracking were investigated. As a result, the incidence of 1/2R cracking was approximately 3.6% in the past, but this could be reduced to 0% with the present invention.
【００３１】[0031]
【発明の効果】以上詳述したように、本発明により、従
来の技術の有する問題を解消し、１／２Ｒ割れの発生が
なく、内部品質が健全な連続鋳造丸鋳片を提供すること
が可能となった。かかる効果を有する本発明の意義は極
めて著しい。[Effects of the Invention] As described in detail above, the present invention solves the problems of the conventional technology and provides a continuously cast round slab with no 1/2R cracking and with a sound internal quality. It has become possible. The significance of the present invention having such effects is extremely significant.
【図１】本発明にかかる連続鋳造丸鋳片のＮ量およびＨ
量が１／２Ｒ割れに及ぼす影響を示すグラフである。[Fig. 1] N amount and H of continuously cast round slab according to the present invention
It is a graph showing the influence of the amount on 1/2R cracking.
Claims (1)
、 Ｓｉ：０．１０〜０．４０％、 Ｍｎ
：０．５０〜１．００％、Ｐ：０．０３０ ％以下、
Ｓ：０．０３０ ％以下、 Ｃｒ：１．２
０％以下、Ｍｏ：０．３０％以下、 ｓｏｌ．Ａｌ：
０．００５ 〜０．１００ ％、Ｎ：６０ｐｐｍ 以下
、Ｈ：４ｐｐｍ 以下、残部Ｆｅおよび不可避的不純物
から成る鋼組成を有し、直径が４００ｍｍ 以上である
内部品質が健全な連続鋳造丸鋳片。[Claim 1] C: 0.20 to 0.80% in weight%
, Si:0.10-0.40%, Mn
: 0.50 to 1.00%, P: 0.030% or less,
S: 0.030% or less, Cr: 1.2
0% or less, Mo: 0.30% or less, sol. Al:
A continuously cast round slab with a sound internal quality and a diameter of 400 mm or more, having a steel composition of 0.005 to 0.100%, N: 60 ppm or less, H: 4 ppm or less, the balance being Fe and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4024691A JPH04279246A (en) | 1991-03-06 | 1991-03-06 | Continuously cast billet with sound inner quality |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4024691A JPH04279246A (en) | 1991-03-06 | 1991-03-06 | Continuously cast billet with sound inner quality |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04279246A true JPH04279246A (en) | 1992-10-05 |
Family
ID=12575350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4024691A Withdrawn JPH04279246A (en) | 1991-03-06 | 1991-03-06 | Continuously cast billet with sound inner quality |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04279246A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1680245A1 (en) * | 2003-10-10 | 2006-07-19 | Nucor Corporation | Casting steel strip |
| US7484551B2 (en) | 2003-10-10 | 2009-02-03 | Nucor Corporation | Casting steel strip |
-
1991
- 1991-03-06 JP JP4024691A patent/JPH04279246A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1680245A1 (en) * | 2003-10-10 | 2006-07-19 | Nucor Corporation | Casting steel strip |
| US7156151B2 (en) | 2003-10-10 | 2007-01-02 | Nucor Corporation | Casting steel strip |
| EP1680245A4 (en) * | 2003-10-10 | 2007-08-29 | Nucor Corp | Casting steel strip |
| US7484551B2 (en) | 2003-10-10 | 2009-02-03 | Nucor Corporation | Casting steel strip |
| AU2004279474B2 (en) * | 2003-10-10 | 2010-05-27 | Nucor Corporation | Casting steel strip |
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| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19980514 |