JPS61276756A - Preventive method of blister defect of cold rolled dead soft steel plate - Google Patents
Preventive method of blister defect of cold rolled dead soft steel plateInfo
- Publication number
- JPS61276756A JPS61276756A JP11666885A JP11666885A JPS61276756A JP S61276756 A JPS61276756 A JP S61276756A JP 11666885 A JP11666885 A JP 11666885A JP 11666885 A JP11666885 A JP 11666885A JP S61276756 A JPS61276756 A JP S61276756A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- steel plate
- cold rolled
- dead soft
- blister
- 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.)
- Granted
Links
Landscapes
- Continuous Casting (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、極低炭素アルミキルド冷延鋼板の製造分野に
所属する技術であって、かかる冷延鋼板を焼鈍する際に
“フクレ欠陥”を生じさせないためのＣａを使う新規に
知見した技術についての提案である。Detailed Description of the Invention (Field of Industrial Application) The present invention is a technology belonging to the field of manufacturing ultra-low carbon aluminium-killed cold-rolled steel sheets, and is a technique for eliminating "blister defects" when annealing such cold-rolled steel sheets. This is a proposal for a newly discovered technology that uses Ca to prevent this from occurring.
（従来の技術）
最近、２次精錬技術の発達に伴い極低炭素アルミキルド
鋼の連続鋳造が可能になってきた。それを可能にしたの
は脱ガス技術の進歩であり、事実その結果として非金属
介在物（以下単に「介在物」という）の少ない清浄鋼の
製造が可能になった。(Prior Art) Recently, with the development of secondary refining technology, continuous casting of ultra-low carbon aluminum killed steel has become possible. This has been made possible by advances in degassing technology, and as a result, it has become possible to produce clean steel with fewer nonmetallic inclusions (hereinafter simply referred to as "inclusions").
しかし、それも主としてコストの面などで限界があった
。However, there were limitations mainly in terms of cost.
加えて従来は、介在物の大きさを炭素含有量との関連で
問題にするようなことはほとんどなく、以下にのべるよ
うな問題点を抱えていた。In addition, in the past, the size of inclusions was rarely considered as a problem in relation to carbon content, and the following problems were posed.
（発明が解決しようとする問題点）
極低炭素冷延板を焼鈍すると、焼鈍済み鋼板の表面に、
幅１〜４ｍ長さ１〜６ｃＩ１１の***部分、いわゆる“
フクレ欠陥”が発生することが判った。(Problem to be solved by the invention) When an ultra-low carbon cold rolled sheet is annealed, on the surface of the annealed steel sheet,
A raised part with a width of 1 to 4 m and a length of 1 to 6 cI11, the so-called “
It was found that "blister defects" occurred.
このフクレ欠陥は、鋼中の炭素含有量が０．０１５重量
％以下のものにとりわけ多く発生し、そのために製品歩
留りの大巾な低下を招いていた。This blistering defect occurs particularly frequently in steels in which the carbon content is 0.015% by weight or less, resulting in a significant decrease in product yield.
（問題点を解決するための手段）
極低炭素アルミキルド鋼製造時に起る上述の如゛き現象
に対し、本発明は、
Ｃ５０．０１５重量％を含有するアルミキルド溶鋼中に
、溶製段階もしくは連続鋳造時にＣａまたはＣａ合金を
添加することにより、鋼中に２〜４０重ｉｔｐｐｍの金
属Ｃａを残留させてＣａＯ−＾１２０３系介在物が生成
するように処理するという方法、
を採用して上述の課題を解決するようにした。(Means for Solving the Problems) In order to deal with the above-mentioned phenomenon that occurs during the production of ultra-low carbon aluminum killed steel, the present invention provides a solution to the above-mentioned phenomenon that occurs during the production of ultra-low carbon aluminum killed steel. By adding Ca or Ca alloy at the time of casting, 2 to 40 weight itppm of metallic Ca is left in the steel so that CaO-^1203-based inclusions are generated. Tried to solve the problem.
つまり本発明は、鋼中に２〜４０ｆｔｆｐｐｍの金属Ｃ
ａが残留するように処理することによって、Ａ Ｉ １
０３介在物をＣａＯ−＾１２０．系介在物に変化させ、
その融点の低下を図ることで、該４１ ！０３介在物を
起因とする焼鈍時のフクレ欠陥生成の防止を図るように
したのである。In other words, the present invention provides 2 to 40 ftfppm of metal C in steel.
By processing so that a remains, A I 1
03 inclusions as CaO-^120. change into system inclusions,
By lowering its melting point, the 41! This is to prevent the formation of blistering defects during annealing caused by 03 inclusions.
（作用）
本発明者らの研究によると、Ｃ含有量が０．０１５重景
置板下のアルミキルド冷延鋼板の場合、これを焼鈍する
と多くの場合フクレ欠陥を生じさせることが判った。そ
の原因としては、色々考えられるが、鋼中の非金属介在
物とくにＡ ｌ ｇｏｚの影響が最も大きい。(Function) According to the research conducted by the present inventors, it has been found that in the case of an aluminium-killed cold-rolled steel sheet with a C content of 0.015, blistering defects occur in many cases when the steel sheet is annealed. Although various causes can be considered, the influence of nonmetallic inclusions in the steel, especially Al goz, is the most significant.
即ち、低炭素鋼になると地鉄（マトリックス）と介在物
との変形強さに著しく差があるために、冷間圧延を施す
と、硬いＡ １２０３に対して軟らかいマトリックスの
部分の方の伸びが大きくなり、その結果両者の境界部分
にボイドを形造る。このボイドはＡｊ２．Ｑ、のサイズ
に比例しており、介在物が大きくなればなるほど大きく
なる。ところで、こうしたボイドを有する冷延鋼板を焼
鈍すると、そのボイド中に雰囲気ガス（ＡＸガス）中の
Ｒ２が侵入するが、冷却時特に急冷時にＲ２の溶解度が
低下するので、結局ボイド中のＲ２分圧が上昇し、＾１
２０．近傍の鋼板表面を膨出させるというフクレ欠陥を
生むのである。In other words, when it comes to low carbon steel, there is a significant difference in deformation strength between the base iron (matrix) and inclusions, so when cold rolling is applied, the elongation of the soft matrix part is greater than that of the hard A1203. As a result, a void is formed at the boundary between the two. This void is Aj2. It is proportional to the size of Q, and the larger the inclusion, the larger it becomes. By the way, when a cold-rolled steel sheet having such voids is annealed, R2 in the atmospheric gas (AX gas) enters into the voids, but the solubility of R2 decreases during cooling, especially during rapid cooling, so the R2 in the voids eventually disappears. The pressure increases, ^1
20. This causes a blistering defect in which the surface of the nearby steel plate bulges out.
かかるフクレ欠陥は、上記ボイドが小さいとき、即ちＡ
Ｉｔ０２介在物の大きさが小さいときには、上記内圧の
上昇が小さいために発生しないことが判った。そして、
このフクレ欠陥を生むＡ ｌｔ、０２の鋼中へのトラッ
プＵについて研究したところ、その大部分はＡＩｔ２０
２を主成分としている浸漬ノズルに凝集付着したＡ Ｊ
、Ｏ，の一部が該ノズル表面から離脱して運ばれてく
るということがわかった。従って、このフクレを防ぐに
はＡ ＩＩ ｚ（ｈが浸漬ノズルに付着しないようにす
ることが有効であるという結論を得た。Such a blistering defect occurs when the void is small, that is, A
It has been found that when the size of It02 inclusions is small, the increase in the internal pressure is small, so that they do not occur. and,
When we researched the trap U of Alt, 02 in steel that causes this blistering defect, we found that most of it is caused by Alt20
AJ coagulated and adhered to the immersion nozzle mainly composed of
, O, was found to be partially detached from the nozzle surface and carried away. Therefore, it was concluded that it is effective to prevent A II z(h from adhering to the immersion nozzle) in order to prevent this blistering.
そこで、本発明者らは、溶鋼中にＣａまたはＣａ合金を
添加して残留Ｃａを含む低炭素アルミキルド溶鋼につい
て連続鋳造を試みたところ、上記Ａ １２ ｔｏ＊介在
物は低融点のＣａ０−Ａ ｌ１ｔａｘ系介在物となって
、その融点低下分だけ浸漬ノズルへのＡ ｌ ｔｏｓの
凝集付着が抑制できることを突きとめた。第２図は、金
属前Ｃａの含有量と浸漬ノズル詰り指数との関係を示す
ものであるが、２重ｌｐｐｍ以上の残留Ｃａ量ではノズ
ル詰り指数が著しく低下し、いわゆるＣａ０−ＡＩ１２
０３系複合介在物の生成が予測された。従って、Ｃａ≧
２ ｐｐｍ含有する溶鋼を上記浸漬ノズルを通じ連続鋳
造して得た低炭素アルミキルド冷延鋼板場合には、ノズ
ルへのＡ Ｊ ｇｏ３凝集付着が無いのでフクレ欠陥が
発生しづらいことがわかる。Therefore, the present inventors added Ca or Ca alloy to molten steel and attempted continuous casting of low carbon aluminum killed molten steel containing residual Ca, and found that the above A 12 to * inclusions were caused by low melting point Ca0-A l1tax It has been found that the coagulation and adhesion of Al tos to the immersion nozzle can be suppressed by the amount of the lowered melting point of the Al tos. Figure 2 shows the relationship between the pre-metal Ca content and the immersion nozzle clogging index.When the amount of residual Ca exceeds 2 lppm, the nozzle clogging index decreases significantly, and the so-called Ca0-AI12
The formation of 03-based composite inclusions was predicted. Therefore, Ca≧
It can be seen that in the case of a low carbon aluminum killed cold rolled steel sheet obtained by continuously casting molten steel containing 2 ppm through the above-mentioned immersion nozzle, blistering defects are less likely to occur because there is no A J go3 agglomeration adhesion to the nozzle.
このＣａの含有量については、４０重量ｐｐｍ以上含有
させると、Ｃａのもつ酸素親和力の故に鋼板表面に錆（
酸化）が生じやすくなり、清浄な鋼板表面を得ることが
難しくなるので、上限の設定が必要である。If the Ca content exceeds 40 ppm by weight, the surface of the steel plate will rust due to the oxygen affinity of Ca.
It is necessary to set an upper limit because it becomes difficult to obtain a clean steel plate surface.
なお、第２図中の浸漬ノズル詰り指数は、浸漬ノズルの
完全閉塞を５．０としたときのノズル詰りの程度を指標
化したものである。上述したＣａもしくはＣａ合金の添
加は、塊状のままかワイヤ状にして脱ガス設備あるいは
、モールドで行う。The immersion nozzle clogging index in FIG. 2 is an index of the degree of nozzle clogging when the immersion nozzle is completely blocked as 5.0. The above-mentioned addition of Ca or Ca alloy is carried out in the form of a lump or in the form of a wire using a degassing facility or a mold.
（実施例）
本発明法に従って実施した結果を以下に説明する。Ｃａ
−Ａｌ合金（Ｃａ ： ３５％、Ａｊ！：６５％）を、
Ｒ１１脱ガス設備内に投入し、鋼中の金属前Ｃａが５゜
１０、１５．２５．３５ｐｐｍ残留するように調整しこ
うして得られた冷延鋼板の各焼鈍コイルについて、フク
レ発生率（フクレ欠陥の発生したコイル数の割合）を調
べた。その結果を第１図に示すが、Ｃａ含有量が２重量
ｐｐｍを超えるとフクレ欠陥の発生は顕著に低下してい
る。これはまた上記第１図に示した浸漬ノズル詰り指数
の臨界量とも一致しており、本発明の作用効果が確認で
きた。(Example) The results carried out according to the method of the present invention will be explained below. Ca
-Al alloy (Ca: 35%, Aj!: 65%),
The blister occurrence rate (blister defect The ratio of the number of coils that occurred was investigated. The results are shown in FIG. 1, and it can be seen that when the Ca content exceeds 2 ppm by weight, the occurrence of blistering defects is significantly reduced. This also coincides with the critical value of the submerged nozzle clogging index shown in FIG. 1 above, confirming the effects of the present invention.
（発明の効果）
以上説明したように本発明によれば、極低炭素アルミキ
ルド冷延鋼板であっても、焼鈍時のフクレ欠陥を確実に
阻止ないしは減少させることかできる。(Effects of the Invention) As explained above, according to the present invention, it is possible to reliably prevent or reduce blistering defects during annealing even in ultra-low carbon aluminum killed cold rolled steel sheets.
第１図は、本発明実施例における鋼中Ｃａ含有量とフク
レ欠陥発生率との関係を示すグラフ、第２図は、鋼中Ｃ
ａ含有量と浸漬ノズル詰り指数との関係を示すグラフで
ある。
ン
第１図
Ｃ４倉有量（ＰＰＭ）
第２図
Ｃａｌ＃ｉＡ量（ｐｐｙｎ）FIG. 1 is a graph showing the relationship between Ca content in steel and blistering defect occurrence rate in Examples of the present invention, and FIG.
It is a graph showing the relationship between the a content and the immersion nozzle clogging index. Fig. 1 C4 storage quantity (PPM) Fig. 2 Cal#iA quantity (ppyn)
Claims (1)
中に、溶製段階もしくは連続鋳造時にＣａまたはＣａ合
金を添加することにより、鋼中に２〜４０重量ｐｐｍの
金属Ｃａを残留させてＣａＯ−Ａｌ＿２Ｏ＿３系介在物
が生成するように処理することを特徴とする極低炭素冷
延鋼板のフクレ欠陥防止方法1. By adding Ca or Ca alloy to aluminium-killed molten steel containing C≦0.015% by weight during the melting stage or continuous casting, 2 to 40 ppm by weight of metallic Ca remains in the steel and CaO - A method for preventing blistering defects in ultra-low carbon cold-rolled steel sheets, characterized by processing to generate Al_2O_3-based inclusions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60116668A JP2559692B2 (en) | 1985-05-31 | 1985-05-31 | Anti-blurring defect prevention method for ultra low carbon cold rolled steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60116668A JP2559692B2 (en) | 1985-05-31 | 1985-05-31 | Anti-blurring defect prevention method for ultra low carbon cold rolled steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61276756A true JPS61276756A (en) | 1986-12-06 |
| JP2559692B2 JP2559692B2 (en) | 1996-12-04 |
Family
ID=14692932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60116668A Expired - Lifetime JP2559692B2 (en) | 1985-05-31 | 1985-05-31 | Anti-blurring defect prevention method for ultra low carbon cold rolled steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2559692B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07100588A (en) * | 1993-09-30 | 1995-04-18 | Nippon Steel Corp | Production of cast double layer slab |
| EP0709469A1 (en) | 1994-10-18 | 1996-05-01 | Kawasaki Steel Corporation | Method of producing molten aluminium-killed steel for thin steel sheet |
| FR2792234A1 (en) * | 1999-04-15 | 2000-10-20 | Lorraine Laminage | Low or ultra-low carbon steel ladle treatment,, after or during aluminum killing and prior to continuous casting, comprises calcium addition in the presence of a small quantity of magnesium |
| US6841123B1 (en) | 1999-10-06 | 2005-01-11 | Jfe Steel Corporation | Rust-resistant calcium steel |
| US9017492B2 (en) | 2003-11-05 | 2015-04-28 | Nippon Steel & Sumitomo Metal Corporation | Thin gauge steel sheet excellent in surface conditions, formability, and workability and method for producing the same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5651861A (en) * | 1979-10-03 | 1981-05-09 | Toshiba Corp | Manufacture of switching element |
-
1985
- 1985-05-31 JP JP60116668A patent/JP2559692B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5651861A (en) * | 1979-10-03 | 1981-05-09 | Toshiba Corp | Manufacture of switching element |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07100588A (en) * | 1993-09-30 | 1995-04-18 | Nippon Steel Corp | Production of cast double layer slab |
| EP0709469A1 (en) | 1994-10-18 | 1996-05-01 | Kawasaki Steel Corporation | Method of producing molten aluminium-killed steel for thin steel sheet |
| FR2792234A1 (en) * | 1999-04-15 | 2000-10-20 | Lorraine Laminage | Low or ultra-low carbon steel ladle treatment,, after or during aluminum killing and prior to continuous casting, comprises calcium addition in the presence of a small quantity of magnesium |
| WO2000062957A1 (en) * | 1999-04-15 | 2000-10-26 | Usinor | Treatment for improving the castability of aluminium killed continuously cast steel |
| JP2002542034A (en) * | 1999-04-15 | 2002-12-10 | ユジノール | Treatment to improve castability of aluminum killed continuous cast steel |
| US6841123B1 (en) | 1999-10-06 | 2005-01-11 | Jfe Steel Corporation | Rust-resistant calcium steel |
| US9017492B2 (en) | 2003-11-05 | 2015-04-28 | Nippon Steel & Sumitomo Metal Corporation | Thin gauge steel sheet excellent in surface conditions, formability, and workability and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2559692B2 (en) | 1996-12-04 |
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