JPH08176641A - Manufacture of highly cleaned stainless steel - Google Patents
Manufacture of highly cleaned stainless steelInfo
- Publication number
- JPH08176641A JPH08176641A JP32339094A JP32339094A JPH08176641A JP H08176641 A JPH08176641 A JP H08176641A JP 32339094 A JP32339094 A JP 32339094A JP 32339094 A JP32339094 A JP 32339094A JP H08176641 A JPH08176641 A JP H08176641A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- steel
- stainless steel
- ladle
- refining
- 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- Withdrawn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
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、取鍋内における精錬に
よって、介在物を効率よく低減するとともに軟質化する
ことにより、表面欠陥の極めて少ない高清浄ステンレス
鋼を製造する方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing highly clean stainless steel having very few surface defects by efficiently reducing inclusions and softening them by refining in a ladle.
【０００２】[0002]
【従来の技術】ステンレス鋼において、介在物が存在す
ると表面欠陥の原因となり易く、特に薄板においては、
５０μｍ以上の大型介在物が存在すると不良品となる場
合が多い。従来、大型介在物の低減対策としては、タン
ディッシュの大型化およびタンディッシュに堰を設置す
る等により介在物の浮上分離を図る方法が知られてい
る。2. Description of the Related Art In stainless steel, the presence of inclusions tends to cause surface defects, especially in thin sheets.
The presence of large inclusions of 50 μm or more often results in defective products. Conventionally, as a measure for reducing large inclusions, a method of increasing the size of the tundish and installing a weir on the tundish to float and separate the inclusions is known.
【０００３】一方、取鍋内の溶鋼にＣａＯ，ＣａＦ2 を
主成分とする粉体を不活性ガスとともに吹込む粉体吹き
込み処理により、スラグのＡｌ2 Ｏ3 をＣａＯ・Ａｌ2
Ｏ3等の複合化合物として浮上分離する方法が、例えば
特開昭６２−１８５８２０号公報によって知られてい
る。しかしながら、このような方法をとっても、大型介
在物を十分に浮上分離することは困難であり、またＡｌ
2 Ｏ3 やＭｇＯ等の硬質介在物が残存して、製品におけ
る表面欠陥の発生を十分に防止できなかった。[0003] On the other hand, CaO into the molten steel in the ladle, the powder blown powder blowing process together with the inert gas mainly composed of CaF 2, the Al 2 O 3 slag CaO · Al 2
A method of floating separation as a composite compound such as O 3 is known, for example, from JP-A-62-185820. However, even if such a method is adopted, it is difficult to sufficiently float and separate large inclusions.
Hard inclusions such as 2 O 3 and MgO remained, and it was not possible to sufficiently prevent the occurrence of surface defects in the product.
【０００４】[0004]
【発明が解決しようとする課題】本発明は、ステンレス
溶鋼の取鍋内における精錬において、介在物を効率よく
低減するとともに軟質化することにより、表面欠陥の極
めて少ない製品を製造することを課題とする。SUMMARY OF THE INVENTION It is an object of the present invention to produce a product having extremely few surface defects by efficiently reducing inclusions and softening them during refining of molten stainless steel in a ladle. To do.
【０００５】[0005]
【課題を解決するための手段】前記課題を解決する本発
明の高清浄ステンレス鋼の製造方法の要旨は下記のとお
りである。主精錬炉における精錬によって酸化したクロ
ムを、シリコンを主成分とする合金により回収する還元
処理を行い、続いて前記主精錬炉より取鍋に出鋼し、該
取鍋内においてガスバブリング処理または粉体吹き込み
処理を行うステンレス鋼精錬において、前記ガスバブリ
ング処理を行う場合は、（１）前記主精錬炉より溶鋼と
ともに出鋼されるスラグの塩基度（Ｔ．ＣａＯ／ＳｉＯ
2 ）を１．４〜１．８となるように調整し、かつ（Ａｌ
2 Ｏ3 ）濃度と（ＭｇＯ）濃度の和を１９．０ｗｔ％以
下となるように調整すること、（２）前記ガスバブリン
グ処理において、不活性ガスを４０ｌ／トン−溶鋼以上
吹込むことを特徴とする。The summary of the method for producing highly clean stainless steel according to the present invention for solving the above problems is as follows. Chromium oxidized by refining in the main smelting furnace is subjected to a reduction treatment to recover with an alloy containing silicon as a main component, and then steel is tapped from the main smelting furnace into a ladle, and gas bubbling treatment or powder in the ladle In the case of performing the gas bubbling treatment in the stainless steel refining in which the body blowing treatment is performed, (1) the basicity (T.CaO / SiO) of the slag that is tapped together with the molten steel from the main refining furnace
2 ) is adjusted to be 1.4 to 1.8, and (Al
Adjusting the sum of the 2 O 3 ) concentration and the (MgO) concentration to be 19.0 wt% or less, and (2) in the gas bubbling process, injecting an inert gas of 40 l / ton-molten steel or more. And
【０００６】また、前記粉体吹込み処理を行う場合は、
（１）前記主精錬炉より溶鋼とともに出鋼されるスラグ
の塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜１．８と
なるように調整し、かつ（Ａｌ2 Ｏ3 ）濃度と（Ｍｇ
Ｏ）濃度の和を２１．０ｗｔ％以下となるように調整す
ること、（２）前記粉体吹込み処理においてＣａＯ，Ｃ
ａＦ2 を主成分とする粉体を不活性ガスとともに２ｋｇ
／トン−溶鋼以上吹込むこと、（３）続いて不活性ガス
を５０ｌ／トン−溶鋼以上吹込むことを特徴とする。When performing the powder blowing process,
(1) The basicity (T.CaO / SiO 2 ) of the slag tapped together with the molten steel from the main refining furnace is adjusted to be 1.4 to 1.8, and the (Al 2 O 3 ) concentration is adjusted. (Mg
And (2) CaO, C in the powder blowing process.
2 kg of powder containing aF 2 as the main component together with an inert gas
/ Ton-molten steel or more, and (3) subsequently, 50 l / ton-molten steel or more is blown.
【０００７】次に、前記ガスバブリング処理を行う場合
における構成要件の限定理由について説明する。図１
は、ＡＯＤ炉においてＳＵＳ３０４ステンレス鋼を酸化
精錬による脱炭精錬をし、該脱炭精錬によって酸化した
クロムをシリコンを主成分とする合金により還元処理を
し、続いてＡＯＤ炉より取鍋に出鋼し、続いて該取鍋内
においてアルゴンガスを吹込むガスバブリング処理を行
った場合の、ＡＯＤ炉より溶鋼とともに出鋼されるスラ
グの組成と該溶鋼を用いて製造した薄板の表面欠陥発生
率の関係を示している。Next, the reasons for limiting the constituent requirements when the gas bubbling process is performed will be described. FIG.
Is a decarburization refining of SUS304 stainless steel by oxidation refining in an AOD furnace, and a reduction treatment of chromium oxidized by the decarburization refining with an alloy containing silicon as a main component, followed by tapping into a ladle from the AOD furnace. Of the composition of the slag that is tapped together with the molten steel from the AOD furnace and the surface defect occurrence rate of the thin plate manufactured using the molten steel when a gas bubbling process in which an argon gas is blown in the ladle is subsequently performed. It shows the relationship.
【０００８】なお、薄板の表面欠陥発生率は、冷延鋼帯
を全幅×長さ１０００ｍｍの面に区分し、介在物起因の
表面欠陥が発生している面の割合で表示した。また、ガ
スブリング処理におけるアルゴンガス吹込み量は４０ｌ
／トン−溶鋼とした。図１より、表面欠陥発生率を大幅
に低減するためには、スラグの塩基度（Ｔ．ＣａＯ／Ｓ
ｉＯ2 ）を１．４〜１．８となるように調整し、かつ
（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）濃度の和を１９．０ｗ
ｔ％以下となるように調整することが必要である。The surface defect occurrence rate of the thin plate is expressed by the ratio of the surface in which the surface defects due to inclusions are generated by dividing the cold-rolled steel strip into the surfaces having the total width × the length of 1000 mm. In addition, the amount of argon gas blown in the gas bling process is 40 l.
/ Ton-Molten steel. From FIG. 1, in order to significantly reduce the surface defect occurrence rate, the basicity of slag (T.CaO / S
iO 2 ) is adjusted to be 1.4 to 1.8, and the sum of the (Al 2 O 3 ) concentration and the (MgO) concentration is 19.0 w.
It is necessary to adjust it to be t% or less.
【０００９】図２は、ＡＯＤ炉において前記同様の精錬
を行ったＳＵＳ３０４ステンレス鋼に取鍋内においてガ
スバブリング処理を行った場合の、アルゴンガス吹込み
量と該溶鋼を用いて製造した薄板の表面欠陥発生率の関
係を示している。なお、溶鋼とともに出鋼されるスラグ
の塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜１．８に
調整し、（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）濃度の和を１
９．０ｗｔ％に調整した。FIG. 2 shows the amount of argon gas blown and the surface of a thin plate manufactured by using the molten steel when SUS304 stainless steel which has been subjected to the same refining as above in an AOD furnace is subjected to gas bubbling treatment in a ladle. The relationship of the defect occurrence rate is shown. The basicity (T.CaO / SiO 2 ) of the slag that is tapped together with the molten steel is adjusted to 1.4 to 1.8, and the sum of the (Al 2 O 3 ) concentration and the (MgO) concentration is 1
It was adjusted to 9.0 wt%.
【００１０】図２より、表面欠陥発生率を大幅に低減す
るためには、アルゴンガス吹込み量を４０ｌ／トン−溶
鋼以上とすることが必要である。次に、前記粉体吹込み
処理を行う場合における限定理由について説明する。図
３は、ＡＯＤ炉においてＳＵＳ３０４ステンレス鋼を酸
化精錬による脱炭処理をし、該脱炭処理によって酸化し
たクロムをシリコンを主成分とする合金により回収する
還元処理を行い、続いてＡＯＤ炉より取鍋に出鋼し、続
いて該取鍋内において、粉体（ＣａＯ−４０％Ｃａ
Ｆ2 ）をアルゴンガスとともに吹込む粉体吹込み処理を
行い、続いてアルゴンガスを吹込んだ場合の、ＡＯＤ炉
より溶鋼とともに出鋼されるスラグの組成と該溶鋼を用
いて製造した薄板の表面欠陥発生率の関係を示してい
る。From FIG. 2, in order to significantly reduce the surface defect generation rate, it is necessary to set the argon gas blowing amount to 40 l / ton-molten steel or more. Next, the reasons for limitation when performing the powder blowing process will be described. In FIG. 3, SUS304 stainless steel is subjected to decarburization treatment by oxidative refining in an AOD furnace, and reduction treatment for recovering chromium oxidized by the decarburization treatment with an alloy containing silicon as a main component is performed. Steel is tapped in a pan, and then powder (CaO-40% Ca) is placed in the ladle.
F 2) was subjected to blown powder blow process with argon gas, followed by the case forme blowing argon gas, the thin plate was prepared using the slag composition and solution steels tapping with the molten steel from the AOD furnace The relationship between the surface defect occurrence rates is shown.
【００１１】なお、粉体吹込み処理における粉体吹込み
量は２ｋｇ／トン−溶鋼とし、粉体吹込み処理後におけ
るアルゴンガス吹込み量は５０ｌ／トン−溶鋼とした。
図３より、表面欠陥発生率を大幅に低減するためには、
ＡＯＤ炉より溶鋼とともに出鋼されるスラグの塩基度
（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜１．８となるよう
に調整し、かつ（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）濃度の
和を２１．０ｗｔ％以下となるように調整することが必
要である。The powder blowing amount in the powder blowing process was 2 kg / ton-molten steel, and the argon gas blowing amount after the powder blowing process was 50 l / ton-molten steel.
From FIG. 3, in order to significantly reduce the surface defect occurrence rate,
AOD furnace slag basicity to be tapped with the molten steel from (T.CaO / SiO 2) was adjusted so as to have a 1.4 to 1.8, and (Al 2 O 3) concentration (MgO) concentration It is necessary to adjust the sum to 21.0 wt% or less.
【００１２】図４は、ＡＯＤ炉において前記同様の精錬
を行ったＳＵＳ３０４ステンレス溶鋼に、取鍋内におい
て粉体（ＣａＯ−４０％ＣａＦ2 ）をアルゴンガスとと
もに吹込む粉体吹込み処理を行った場合の、粉体吹込み
量と該溶鋼を用いて製造した薄板の表面欠陥発生率の関
係を示している。なお、ＡＯＤ炉より溶鋼とともに出鋼
されるスラグの塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．
４〜１．８に調整し、（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）
濃度の和を２１．０ｗｔ％に調整した。また、粉体吹込
み処理後におけるアルゴンガス吹込み量は５０ｌ／トン
−溶鋼とした。FIG. 4 shows a powder injection process of injecting powder (CaO-40% CaF 2 ) together with argon gas into molten SUS304 stainless steel which has been refined in the AOD furnace in the same manner as described above. In this case, the relationship between the powder injection amount and the surface defect occurrence rate of a thin plate manufactured using the molten steel is shown. The basicity (T.CaO / SiO 2 ) of the slag that was tapped together with the molten steel from the AOD furnace was 1.
Adjusted to 4 to 1.8, (Al 2 O 3 ) concentration and (MgO)
The sum of the concentrations was adjusted to 21.0 wt%. The amount of argon gas blown after the powder blowing process was 50 l / ton-molten steel.
【００１３】図４より、表面欠陥発生率を大幅に低減す
るためには、粉体吹込み量を２ｋｇ／トン−溶鋼以上と
することが必要である。図５は、ＡＯＤ炉において前記
同様の精錬を行ったＳＵＳ３０４ステンレス溶鋼に、取
鍋内において粉体吹込み処理を行った後、アルゴンガス
の吹込みを行った場合の、アルゴンガス吹込み量と該溶
鋼を用いて製造した薄板の表面欠陥発生率の関係を示し
ている。From FIG. 4, in order to significantly reduce the surface defect occurrence rate, it is necessary to set the powder injection amount to 2 kg / ton-molten steel or more. FIG. 5 shows the amount of argon gas blown when argon gas was blown into the molten SUS304 stainless steel that had been refined in the AOD furnace in the same manner as described above, after the powder was blown in the ladle. The relationship of the surface defect generation rate of the thin plate manufactured using the molten steel is shown.
【００１４】なお、ＡＯＤ炉より溶鋼とともに出鋼され
るスラグの塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜
１．８に調整し、（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）濃度
の和は２１．０ｗｔ％に調整した。また粉体吹込み処理
における粉体吹込み量は２ｋｇ／トン−溶鋼とした。図
５より、表面欠陥発生率を大幅に低減するためには、粉
体吹込み処理後におけるアルゴンガス吹込み量を５０ｌ
／トン−溶鋼以上とすることが必要である。The basicity (T.CaO / SiO 2 ) of the slag tapped together with the molten steel from the AOD furnace is 1.4 to
It was adjusted to 1.8 and the sum of the (Al 2 O 3 ) concentration and the (MgO) concentration was adjusted to 21.0 wt%. The powder injection amount in the powder injection treatment was 2 kg / ton-molten steel. From FIG. 5, in order to drastically reduce the surface defect occurrence rate, the amount of argon gas blown after the powder blowing process was 50 l.
/ Ton-It is necessary to make it more than molten steel.
【００１５】なお、以上の説明では主精錬炉としてＡＯ
Ｄ炉を用いたが、これに代えて転炉やＶＯＤ炉等を用い
てもよい。また、不活性ガスとしてアルゴンガスを用い
たが、これに代えて窒素ガス等の他の不活性ガスを用い
てもよい。また、製品として薄板の例を説明したが、本
発明は線材等、他の製品にも適用される。鋼種に関して
はＳＵＳ３０４で説明したが、本発明はＮｉ系ステンレ
ス鋼のみならず、Ｃｒ系ステンレス鋼へも適用可能であ
る。In the above explanation, AO is used as the main refining furnace.
Although the D furnace is used, a converter or a VOD furnace may be used instead. Further, although the argon gas is used as the inert gas, other inert gas such as nitrogen gas may be used instead of the argon gas. Further, although the example of the thin plate has been described as the product, the present invention is also applied to other products such as a wire rod. Although the steel type has been described in SUS304, the present invention is applicable not only to Ni-based stainless steel but also to Cr-based stainless steel.
【００１６】[0016]
【作用】本発明では、主精錬炉における脱炭精錬によっ
て酸化したクロムをシリコンを主成分とする合金により
還元処理を行っているため、添加したシリコン〔Ｓｉ〕
と溶鋼中の〔Ｏ〕が反応して、（１）式による脱酸反応
が進行する。 Ｓｉ ＋ ２Ｏ → （ＳｉＯ2 ） ………… （１）式 （１）式による脱酸反応の進行に伴って、溶鋼中に懸濁
する介在物中に占める（ＳｉＯ2 ）濃度が増大する。こ
の結果、介在物中に占める（Ａｌ2 Ｏ3 ）濃度が減少し
て介在物の組成変化が起き、介在物組成は（ＣａＯ−Ｓ
ｉＯ2 ）主体となる。In the present invention, since chromium treated by decarburization and refining in the main refining furnace is reduced by an alloy containing silicon as a main component, the added silicon [Si]
[O] in the molten steel reacts with each other, and the deoxidation reaction according to the formula (1) proceeds. Si + 2 O → (SiO 2 ) ... (1) Formula (1) As the deoxidation reaction proceeds, the (SiO 2 ) concentration in the inclusions suspended in the molten steel increases. . As a result, the concentration of (Al 2 O 3 ) in the inclusions decreases and the composition of the inclusions changes, and the composition of the inclusions becomes (CaO-S
iO 2 ) Mainly.
【００１７】また、脱酸を（１）式によるＳｉ脱酸によ
って行っているため、（２）式によるＡｌ脱酸をおこな
った場合と比べて（Ａｌ2 Ｏ3 ）の生成が少ない。 ２Ａｌ ＋ ３Ｏ → （Ａｌ2 Ｏ3 ） ………… （２）式 （Ａｌ2 Ｏ3 ）は圧延時に引き伸ばされ難いが、（Ｃａ
Ｏ−ＳｉＯ2 ）は圧延時に引き伸ばされ易いため屈伸・
分断されて表面欠陥にはなり難い。Further, since the deoxidation is carried out by the Si deoxidation according to the formula (1), the production of (Al 2 O 3 ) is less than that in the case where the Al deoxidation according to the formula (2) is carried out. 2 Al + 3 O → (Al 2 O 3 ) ... (2) The formula (Al 2 O 3 ) is difficult to be stretched during rolling, but (Ca
O-SiO 2) • The bending and stretching for easy stretched during rolling
It is difficult to be divided into surface defects.
【００１８】また本発明では、主精錬炉より溶鋼ととも
に出鋼されるスラグ中の塩基度（Ｔ．ＣａＯ／Ｓｉ
Ｏ2 ）が低い場合は、（１）式による脱酸反応が進行し
難いため、前記介在物の組成変化は小さくなる。一方、
塩基度が高い場合、（１）式による脱酸反応は進行する
ものの、酸素が過剰に低下するため、主精錬炉を出鋼し
た後の温度降下に伴って、シリコン〔Ｓｉ〕に比べて脱
酸力の強いアルミニウム〔Ａｌ〕による（２）式の反応
が優先して起こり、（Ａｌ2 Ｏ3 ）が生成する。Further, in the present invention, the basicity (T.CaO / Si) in the slag that is tapped together with the molten steel from the main refining furnace.
When O 2 ) is low, the deoxidation reaction according to the formula (1) is difficult to proceed, and the composition change of the inclusions is small. on the other hand,
When the basicity is high, the deoxidation reaction according to the formula (1) proceeds, but oxygen is excessively decreased, so that the deoxidation reaction is higher than that of silicon [Si] due to the temperature drop after tapping the main smelting furnace. The reaction of the formula (2) by aluminum [Al] having a strong acidity is preferentially caused to generate (Al 2 O 3 ).
【００１９】また本発明では、主精錬炉より溶鋼ととも
に出鋼されるスラグ中の（Ａｌ2 Ｏ 3 ）濃度と（Ｍｇ
Ｏ）濃度の和を規制することにより、高融点でかつ圧延
時に引き伸ばされ難い（Ａｌ2 Ｏ3 ）および（ＭｇＯ）
の生成を抑制する。本発明におけるガスバブリング処理
では、スラグ組成を前記のように調整した後に、不活性
ガスを吹込むことにより前記（１）式の反応が促進さ
れ、また次の２つの作用により、溶鋼中に懸濁する（Ａ
ｌ2 Ｏ3 ）および（ＭｇＯ）の浮上分離が促進される。Further, in the present invention, the molten steel is supplied from the main refining furnace.
In the slag (steel)2O 3) Concentration and (Mg
O) By controlling the sum of the concentrations, high melting point and rolling
Sometimes hard to stretch (Al2O3) And (MgO)
Suppress the generation of. Gas bubbling treatment in the present invention
Then, after adjusting the slag composition as described above,
By blowing gas, the reaction of equation (1) is promoted.
And suspended in molten steel by the following two actions (A
l2O3) And (MgO) floating separation is promoted.
【００２０】作用：溶鋼中に懸濁する介在物が、吹込
まれた不活性ガスの気泡に捕捉されることにより、介在
物の浮上分離が促進される。 作用：吹込まれた不活性ガスによる溶鋼の攪拌によ
り、溶鋼中に懸濁する介在物が凝集・合体されて粗大化
することで介在物の浮上分離が促進される。 作用を増大させるためには、前記（１）式の反応を促
進させて介在物をＣａＯ−ＳｉＯ2 主体とし低融点化す
ること、および不活性ガス吹込みによる溶鋼の攪拌力を
増大することが重要である。なお溶鋼の攪拌力を増大す
るためには、不活性ガス吹込み速度を５Ｎｌ／ｍｉｎ以
上とすることが望ましい。吹込み速度の上限は、耐火物
からの汚染等を考慮して２０Ｎｌ／ｍｉｎが望ましい。Action: The inclusions suspended in the molten steel are trapped by the bubbles of the inert gas blown in, whereby the floating separation of the inclusions is promoted. Action: Stirring of the molten steel by the blown inert gas causes the inclusions suspended in the molten steel to aggregate and coalesce to become coarse, thereby promoting floating separation of the inclusions. In order to increase the action, it is necessary to promote the reaction of the formula (1) to lower the melting point of inclusions mainly composed of CaO—SiO 2 and to increase the stirring force of the molten steel by blowing an inert gas. is important. In order to increase the stirring force of the molten steel, it is desirable that the inert gas blowing rate be 5 Nl / min or more. The upper limit of the blowing speed is preferably 20 Nl / min in consideration of contamination from the refractory.
【００２１】本発明における粉体吹込み処理では、前記
ガスバブリング処理の場合と同様にスラグ組成を調整し
た後の溶鋼に、ＣａＯ，ＣａＦ2 を主成分とする粉体を
不活性ガスとともに吹込むことにより、次の２つの作用
により介在物の浮上分離が促進され、また組成変化が起
こる。 作用：前記（３）式に示す反応によって溶鋼中に懸濁
する（ＳｉＯ2 ）は、吹込まれた粉体（ＣａＯ）に吸収
されて凝集化し浮上分離する。In the powder blowing process according to the present invention, the powder containing CaO and CaF 2 as the main components is blown together with the inert gas into the molten steel after adjusting the slag composition as in the case of the gas bubbling process. As a result, the floating separation of inclusions is promoted and the composition changes due to the following two actions. Action: (SiO 2 ) suspended in molten steel by the reaction represented by the above formula (3) is absorbed by the blown powder (CaO), aggregates, and floats and separates.
【００２２】 （ＣａＯ）＋（ＳｉＯ2 ）→（ＣａＯ）・（ＳｉＯ2 ） ……（３）式 作用：（３）式による反応の進行に伴ってスラグ中の
ＳｉＯ2 活量が低減するため、前記（１）式により脱酸
が促進される。（１）式による脱酸反応の進行に伴って
生成する（ＳｉＯ2 ）によって、前記同様に介在物中に
占める（ＳｉＯ 2 ）濃度が増大する。この結果、介在物
の組成変化が起き、介在物組成は延性の高いＣａＯ−Ｓ
ｉＯ2 主体となる。(CaO) + (SiO2) → (CaO) ・ (SiO2) ...... Equation (3) Action: As the reaction according to Equation (3) progresses,
SiO2Since the activity is reduced, deoxidation according to the above formula (1)
Is promoted. With the progress of deoxidation reaction according to equation (1)
Generate (SiO2), In the same manner as above
Occupy (SiO 2) The concentration increases. This results in inclusions
Changes in the composition of CaO-S with high ductility.
iO2Be the subject.
【００２３】作用、を促進させるためには、不活性
ガスを吹込んで溶鋼を攪拌することにより、前記作用
およびを得て、前記（１）式および（３）式の反応を
促進させ、介在物の浮上分離および組成変化を促進させ
ることが重要である。また、粉体にＣａＦ2 を含ませる
ことは、吹込まれた粉体の融体化に寄与し、（３）式の
反応および介在物の凝集化を促進させるために重要であ
る。In order to accelerate the action, an inert gas is blown into the molten steel to stir the molten steel to obtain the action and the reaction of the formulas (1) and (3) to promote the inclusions. It is important to promote the floating separation and compositional change of. Further, the inclusion of CaF 2 in the powder contributes to the melting of the blown powder and is important for promoting the reaction of formula (3) and the agglomeration of inclusions.
【００２４】なお、粉体吹込み処理においては、ガスバ
ブリング処理による作用およびに加えて作用およ
びが得られるため、（Ａｌ2 Ｏ3 ）濃度と（ＭｇＯ）
濃度の和は、ガスバブリング処理の場合と比べて多くて
もよい。In addition, in the powder blowing process, since the action and the action in addition to the action and the effect by the gas bubbling process are obtained, the (Al 2 O 3 ) concentration and the (MgO)
The sum of the concentrations may be larger than that in the gas bubbling process.
【００２５】[0025]
【実施例】ＳＵＳ３０４ステンレス鋼薄板を製造した実
施例について説明する。まず、電気炉にてスクラップお
よび合金鉄を溶解した後、ＡＯＤ炉にて脱炭処理した。
脱炭処理後にＦｅ−ＳｉおよびＣａＯを添加してクロム
還元および脱硫処理をして取鍋に出鋼した。溶鋼の処理
量は６０トンである。EXAMPLE An example of manufacturing a SUS304 stainless steel thin plate will be described. First, scrap and ferroalloy were melted in an electric furnace, and then decarburized in an AOD furnace.
After the decarburization treatment, Fe-Si and CaO were added to carry out chromium reduction and desulfurization treatment, and steel was tapped in a ladle. The throughput of molten steel is 60 tons.
【００２６】なお、ＡＯＤ炉より溶鋼とともに出鋼され
るスラグ中の（Ａｌ2 Ｏ3 ）および（ＭｇＯ）の濃度調
整は、還元・脱硫処理において添加するＡｌの量および
耐火物溶損防止用に添加するＭｇＯの量を調整すること
によって行った。取鍋では、上方から溶鋼中に浸漬した
ランスを通じてアルゴンガスを吹き込むガスバブリング
処理、または粉体をアルゴンガスによって吹込む粉体吹
込み処理を実施した。ガスバブリング処理および粉体吹
込み処理におけるアルゴンガスの、純度は９９．９９９
％以上、流速は１０００Ｎｌ／ｍｉｎであり、所定時間
の処理を実施した。また、粉体吹込み処理での粉体の組
成はＣａＯ−４０％ＣａＦ 2 、粒度は２５０μｍ以下の
ものを用いた。粉体吹込み処理後にアルゴンガスの吹込
み処理を実施した。[0026] The steel was tapped together with the molten steel from the AOD furnace.
(Al in slag2O3) And (MgO) concentration adjustment
The adjustment is the amount of Al added in the reduction / desulfurization treatment and
Adjusting the amount of MgO added to prevent refractory melting
Went by. In the ladle, it was immersed in molten steel from above.
Gas bubbling by blowing argon gas through the lance
Powder blown by processing or blowing powder with argon gas
Incorporation processing was performed. Gas bubbling and powder blowing
The purity of the argon gas in the filling process is 99.999.
% Or more, the flow rate is 1000 Nl / min, and the predetermined time
Was carried out. In addition, the combination of powder in the powder blowing process
Growth is CaO-40% CaF 2, The particle size is less than 250 μm
I used one. Injecting argon gas after powder injection processing
Only the treatment was carried out.
【００２７】取鍋での処理後は、連続鋳造により断面１
６０×１０００ｍｍのスラブ鋳片を製造した。ここで、
ダンディッシュでの溶鋼重量は約７トンとし、鋳造速度
は１トン／ｍｉｎで一定とした。この鋳片を板厚３．０
ｍｍに熱間圧延し、焼鈍・酸洗後に板厚１．０ｍｍに冷
間圧延した。冷延板の表面欠陥発生率は、前述のように
冷延鋼帯を全幅×長さ１０００ｍｍの面に区分し、介在
物起因の表面欠陥が発生している面の割合で表示した。
結果を表１に示す。After the treatment in the ladle, the cross-section 1 is formed by continuous casting.
A slab slab of 60 × 1000 mm was manufactured. here,
The weight of molten steel in Dundish was about 7 tons, and the casting speed was constant at 1 ton / min. This cast piece has a plate thickness of 3.0
It was hot-rolled to mm, annealed and pickled, and then cold-rolled to a plate thickness of 1.0 mm. The surface defect occurrence rate of the cold-rolled sheet was expressed by the ratio of the surface in which the surface defects due to inclusions were generated by dividing the cold-rolled steel strip into the surfaces having the entire width × the length of 1000 mm as described above.
The results are shown in Table 1.
【００２８】本発明例（Ｎｏ．１〜４）では、冷延板の
表面欠陥発生率が極めて少ないのに対して、比較例（Ｎ
ｏ．５〜１１）では本発明の範囲を外れるために冷延板
の表面欠陥発生率が高い。本発明の範囲を満足すること
により、冷延板の表面欠陥発生率を大幅に低減できるこ
とがわかる。In the examples of the present invention (Nos. 1 to 4), the surface defect occurrence rate of the cold-rolled sheet is extremely low, while in the comparative example (N
o. In 5 to 11), the surface defect occurrence rate of the cold-rolled sheet is high because it is out of the range of the present invention. By satisfying the range of the present invention, it can be seen that the surface defect occurrence rate of the cold rolled sheet can be significantly reduced.
【００２９】[0029]
【表１】 [Table 1]
【００３０】[0030]
【発明の効果】本発明によれば、ステンレス鋼の介在物
量を低減するとともに、介在物を軟質化することができ
るので、表面欠陥の極めて少ない製品を製造することが
可能となる。このため、製造歩留が向上するとともに厳
しい品質要求にも応じることができる。According to the present invention, since the amount of inclusions of stainless steel can be reduced and the inclusions can be softened, a product with extremely few surface defects can be manufactured. Therefore, the manufacturing yield is improved and strict quality requirements can be met.
【図１】ガスバブリング処理を行った場合の、処理前の
スラグ組成と薄板の表面欠陥発生率の関係を示す図であ
る。FIG. 1 is a diagram showing a relationship between a slag composition before treatment and a surface defect occurrence rate of a thin plate when a gas bubbling treatment is performed.
【図２】ガスバブリング処理を行った場合の、アルゴン
ガス吹込み量と薄板の表面欠陥発生率の関係を示す図で
ある。FIG. 2 is a diagram showing a relationship between an argon gas blowing amount and a surface defect occurrence rate of a thin plate when a gas bubbling process is performed.
【図３】粉体吹込み処理を行った場合の、処理前のスラ
グ組成と薄板の表面欠陥発生率の関係を示す図である。FIG. 3 is a diagram showing a relationship between a slag composition before treatment and a surface defect occurrence rate of a thin plate when a powder blowing treatment is performed.
【図４】粉体吹込み処理を行った場合の、粉体吹込み量
と薄板の表面欠陥発生率の関係を示す図である。FIG. 4 is a diagram showing a relationship between a powder injection amount and a surface defect occurrence rate of a thin plate when a powder injection process is performed.
【図５】粉体吹込み処理後にアルゴンガスを吹込む処理
を行った場合の、アルゴンガス吹込み量と薄板の表面欠
陥発生率の関係を示す図である。FIG. 5 is a diagram showing the relationship between the amount of argon gas blown and the surface defect occurrence rate of a thin plate when the process of blowing argon gas is performed after the powder blowing process.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 田中 智昭 山口県光市大字島田3434番地 新日本製鐵 株式会社光製鐵所内 (72)発明者 河合 浩之 山口県光市大字島田3434番地 新日本製鐵 株式会社光製鐵所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoaki Tanaka 3434 Shimada, Hitsu-shi, Yamaguchi Prefecture Nippon Steel Co., Ltd. Hikari Steel Works Co., Ltd. (72) Hiroyuki Kawai 3434 Shimada, Hikari-shi, Yamaguchi Prefecture Made in Japan Inside the Kogaku Steel Works
Claims (2)
クロムを、シリコンを主成分とする合金により回収する
還元処理を行い、続いて前記主精錬炉より取鍋に出鋼
し、該取鍋内においてガスバブリング処理を行うステン
レス鋼精錬において、 （１）前記主精錬炉より溶鋼とともに出鋼されるスラグ
の塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜１．８と
なるように調整し、かつ（Ａｌ2 Ｏ3 ）濃度と（Ｍｇ
Ｏ）濃度の和を１９．０ｗｔ％以下となるように調整す
ること、 （２）前記ガスバブリング処理において、不活性ガスを
４０ｌ／トン−溶鋼以上吹込むことを特徴とする高清浄
ステンレス鋼の製造方法。1. A reduction process for recovering chromium oxidized by refining in a main refining furnace by an alloy containing silicon as a main component, and subsequently tapping the steel from the main refining furnace into a ladle, and in the ladle. In stainless steel refining for gas bubbling, (1) adjust the basicity (T.CaO / SiO 2 ) of slag to be tapped together with molten steel from the main refining furnace to be 1.4 to 1.8. , And (Al 2 O 3 ) concentration and (Mg
O) adjusting the sum of the concentrations to be 19.0 wt% or less, (2) In the gas bubbling treatment, 40 l / ton-molten steel or more of an inert gas is blown into the highly clean stainless steel. Production method.
クロムを、シリコンを主成分とする合金により回収する
還元処理を行い、続いて前記主精錬炉より取鍋に出鋼
し、該取鍋内において粉体吹込み処理を行うステンレス
鋼精錬において、 （１）前記主精錬炉より溶鋼とともに出鋼されるスラグ
の塩基度（Ｔ．ＣａＯ／ＳｉＯ2 ）を１．４〜１．８と
なるように調整し、かつ（Ａｌ2 Ｏ3 ）濃度と（Ｍｇ
Ｏ）濃度の和を２１．０ｗｔ％以下となるように調整す
ること、 （２）前記粉体吹込み処理においてＣａＯ，ＣａＦ2 を
主成分とする粉体を不活性ガスとともに２ｋｇ／トン−
溶鋼以上を吹込むこと、 （３）続いて不活性ガスを５０ｌ／トン−溶鋼以上吹込
むことを特徴とする高清浄ステンレス鋼の製造方法。2. A reduction treatment for recovering chromium oxidized by refining in a main refining furnace with an alloy containing silicon as a main component, and subsequently tapping steel from the main refining furnace into a ladle, and in the ladle. In stainless steel refining for powder injection treatment, (1) The basicity (T.CaO / SiO 2 ) of slag that is tapped together with molten steel from the main refining furnace should be 1.4 to 1.8. Adjusted and (Al 2 O 3 ) concentration and (Mg
O) so that the sum of the concentrations is 21.0 wt% or less. (2) In the powder blowing process, powder containing CaO and CaF 2 as the main components together with an inert gas at 2 kg / ton-
A method for producing highly clean stainless steel, which comprises blowing at least molten steel, and (3) subsequently blowing at least 50 l / ton of molten gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32339094A JPH08176641A (en) | 1994-12-26 | 1994-12-26 | Manufacture of highly cleaned stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32339094A JPH08176641A (en) | 1994-12-26 | 1994-12-26 | Manufacture of highly cleaned stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08176641A true JPH08176641A (en) | 1996-07-09 |
Family
ID=18154208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32339094A Withdrawn JPH08176641A (en) | 1994-12-26 | 1994-12-26 | Manufacture of highly cleaned stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08176641A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101365525B1 (en) * | 2011-12-21 | 2014-02-20 | (주)포스코 | Two-phase stanless steel and argon oxygen decarburization refining method of the two-phase stainless steel |
| EP3358029A4 (en) * | 2015-09-29 | 2019-05-22 | Nisshin Steel Co., Ltd. | High-strength stainless steel sheet having excellent fatigue characteristics, and method for manufacturing same |
-
1994
- 1994-12-26 JP JP32339094A patent/JPH08176641A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101365525B1 (en) * | 2011-12-21 | 2014-02-20 | (주)포스코 | Two-phase stanless steel and argon oxygen decarburization refining method of the two-phase stainless steel |
| EP3358029A4 (en) * | 2015-09-29 | 2019-05-22 | Nisshin Steel Co., Ltd. | High-strength stainless steel sheet having excellent fatigue characteristics, and method for manufacturing same |
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