JP2002060831A - Method for producing clean steel - Google Patents
Method for producing clean steelInfo
- Publication number
- JP2002060831A JP2002060831A JP2000250727A JP2000250727A JP2002060831A JP 2002060831 A JP2002060831 A JP 2002060831A JP 2000250727 A JP2000250727 A JP 2000250727A JP 2000250727 A JP2000250727 A JP 2000250727A JP 2002060831 A JP2002060831 A JP 2002060831A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- slag
- steel
- concentration
- amount
- 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.)
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Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、清浄性に優れた鋼
の製造方法に関し、詳しくは、取鍋等の溶鋼保持容器に
収容された溶鋼の清浄性を高め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 steel having excellent cleanliness, and more particularly, to a method for improving the cleanliness of molten steel contained in a molten steel holding container such as a ladle.
【０００２】[0002]
【従来の技術】鉄鋼材料の高機能化及び高品質化への要
求の高まりから、鋼中の不純物元素を極限まで低減する
ことが望まれており、溶鋼段階での鋼の高純度化及び高
清浄度化のための技術が必要とされている。鋼中の不純
物元素の１つである酸素は、鋼中に酸化物として存在し
た場合、鋼板における欠陥の原因となる。2. Description of the Related Art As the demand for higher performance and higher quality of steel materials has increased, it has been desired to reduce impurity elements in steel to the utmost. There is a need for technology for cleanliness. Oxygen, one of the impurity elements in steel, when present as an oxide in steel, causes defects in steel sheets.
【０００３】鋼の精錬段階において、鋼中に酸化物を生
成させる要因の１つとして、取鍋等の溶鋼保持容器に収
容された溶鋼と溶鋼上に浮遊するスラグとの反応、即
ち、スラグ中のＦｅＯやＭｎＯ等の低級酸化物による溶
鋼の再酸化が挙げられており、こうした背景からスラグ
による溶鋼の再酸化を防止する対策が実施されている。[0003] In the refining stage of steel, one of the factors that generate oxides in the steel is a reaction between molten steel contained in a molten steel holding vessel such as a ladle and slag floating on the molten steel, that is, a reaction in the slag. And reoxidation of molten steel by lower oxides such as FeO and MnO, and measures against the reoxidation of molten steel by slag are taken from such a background.
【０００４】従来、この対策は溶鋼保持容器内のスラグ
にＡｌ等の脱酸剤（還元剤とも云う）を添加し、スラグ
を還元する方法が採られている。例えば、特開平２−３
０７１１号公報には、精錬炉から取鍋への出鋼直後、未
脱酸状態の溶鋼上で浮遊するスラグ上に脱酸剤を添加し
てスラグ中のＦｅＯを還元する方法が開示され、特開平
２−９３０１７号公報には、ＲＨ真空脱ガス装置におけ
る真空脱炭処理後に取鍋内スラグにＡｌを添加してスラ
グ中のＦｅＯを還元する方法が開示され、又、特開平７
−３４１１７号公報には、出鋼中若しくは出鋼直後に取
鍋内スラグにスラグ還元に必要な量の一部の脱酸剤を添
加し、真空脱ガス精錬中に残りの脱酸剤を取鍋内スラグ
に添加する方法が開示されている。Conventionally, as a countermeasure, a method of adding a deoxidizing agent such as Al (also referred to as a reducing agent) to slag in a molten steel holding container to reduce the slag has been adopted. For example, Japanese Patent Application Laid-Open
No. 0711 discloses a method of reducing FeO in slag by adding a deoxidizing agent to slag floating on molten steel in an undeoxidized state immediately after tapping from a refining furnace to a ladle. JP-A-2-93017 discloses a method of reducing FeO in slag by adding Al to slag in a ladle after vacuum decarburization treatment in an RH vacuum degassing apparatus.
Japanese Patent No. 34117 discloses that during or immediately after tapping, a part of a deoxidizing agent required for slag reduction is added to slag in a ladle, and the remaining deoxidizing agent is removed during vacuum degassing refining. A method of adding to slag in a pot is disclosed.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記の
特開平２−３０７１１号公報に開示された方法では、溶
鋼が脱酸されるまでは溶鋼中の溶解酸素によりスラグが
酸化されて、スラグ中に新たに低級酸化物が形成され、
溶鋼が脱酸されるまでにスラグの酸素ポテンシャルが上
昇してしまうので、溶鋼が脱酸された後のスラグによる
再酸化を防止できないという問題点がある。多量の脱酸
剤を添加すれば、この問題点は解消されるが、その場合
には脱酸剤の原単位が悪化するという新たな問題点が生
ずる。However, in the method disclosed in Japanese Patent Application Laid-Open No. Hei 2-30711, the slag is oxidized by the dissolved oxygen in the molten steel until the molten steel is deoxidized. New lower oxides are formed,
Since the oxygen potential of the slag increases before the molten steel is deoxidized, there is a problem that reoxidation by the slag after the molten steel is deoxidized cannot be prevented. This problem can be solved by adding a large amount of deoxidizing agent, but in that case, a new problem arises in that the basic unit of the deoxidizing agent is deteriorated.
【０００６】又、特開平２−９３０１７号公報及び特開
平７−３４１１７号公報に開示された方法では、真空脱
ガス精錬中にスラグ還元用の脱酸剤を添加する際に、ス
ラグ中の低級酸化物濃度が不明であるため、添加する脱
酸剤が不足する場合には、スラグの還元が十分に行われ
ず、一方、添加する脱酸剤が過剰の場合には、スラグの
還元用に添加した脱酸剤が溶鋼中に歩留まり、溶鋼中の
Ａｌ濃度の調整が困難になるという問題点がある。In the methods disclosed in JP-A-2-93017 and JP-A-7-34117, when a deoxidizing agent for reducing slag is added during vacuum degassing refining, a lower grade of slag is added. Since the oxide concentration is unknown, if the amount of the added deoxidizing agent is insufficient, the slag is not sufficiently reduced.On the other hand, if the added amount of the deoxidizing agent is excessive, the slag is added for reducing the slag. There is a problem that the deoxidizing agent yielded in the molten steel makes it difficult to adjust the Al concentration in the molten steel.
【０００７】本発明は上記事情に鑑みなされたもので、
その目的とするところは、取鍋等の溶鋼保持容器に収容
された溶鋼のスラグによる再酸化を防止し、酸化物系介
在物が極めて少ない高清浄鋼を安定して製造する方法を
提供することである。[0007] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a method for preventing the reoxidation of molten steel contained in a molten steel holding container such as a ladle by slag, and for stably producing high-purity steel with extremely few oxide-based inclusions. It is.
【０００８】[0008]
【課題を解決するための手段】本発明者等は、上記課題
を解決するために鋭意研究を重ねた。そして、溶鋼をＡ
ｌで脱酸した後に溶鋼とスラグとを強制的に攪拌すれ
ば、溶鋼中のＡｌとスラグ中のＦｅＯ等の鉄酸化物とが
反応するので、スラグ中のＴ．Ｆｅ濃度は迅速に減少
し、それ以降の溶鋼のスラグによる再酸化が防止される
であろうと考えた。尚、Ｔ．Ｆｅとはスラグ中の全ての
鉄酸化物（ＦｅＯやＦｅ2 Ｏ3 ）の鉄分の合計値であ
る。Means for Solving the Problems The present inventors have intensively studied to solve the above problems. And the molten steel is A
If the molten steel and the slag are forcibly stirred after deoxidation with Al, the Al in the molten steel and the iron oxide such as FeO in the slag react with each other. It was thought that the Fe concentration would decrease quickly and prevent subsequent reoxidation of the molten steel by the slag. In addition, T. Fe is the total value of iron in all iron oxides (FeO and Fe 2 O 3 ) in the slag.
【０００９】そこで、ＲＨ真空脱ガス装置を用いた精錬
において、溶鋼の真空脱炭処理終了後に、溶鋼中の溶解
酸素に対応し、溶鋼を脱酸するために必要な量の金属Ａ
ｌと、鋼の成分規格に必要な量の金属Ａｌとを溶鋼に添
加し、金属Ａｌの添加直後に溶鋼中に浸漬させたランス
からＡｒを溶鋼中に吹き込み、溶鋼とスラグとを強制的
に攪拌させた。これにより溶鋼中のＡｌとスラグ中の鉄
酸化物とが反応して、スラグのＴ．Ｆｅは迅速に低下す
ることが分かった。その際、溶鋼中のＡｌ濃度はその分
低下するので、低下した分を追加補充した。Therefore, in the refining using the RH vacuum degassing apparatus, after the vacuum decarburization treatment of the molten steel, the amount of metal A required to deoxidize the molten steel corresponding to the dissolved oxygen in the molten steel is obtained.
l and the amount of metal Al required for the steel component standard are added to the molten steel, and immediately after the addition of the metal Al, Ar is blown into the molten steel from a lance immersed in the molten steel to force the molten steel and the slag. It was allowed to stir. As a result, Al in the molten steel reacts with iron oxide in the slag, and T.V. Fe was found to decrease rapidly. At that time, since the Al concentration in the molten steel decreased by that amount, the decreased amount was additionally supplemented.
【００１０】以上のことから、Ａｌで脱酸された溶鋼に
スラグを還元するために必要な量のＡｌを添加し、その
後、溶鋼へ不活性ガスを吹き込み、溶鋼とスラグとを強
制的に攪拌すれば、溶鋼中のＡｌでスラグ中の鉄酸化物
を迅速且つ十分に低減でき、溶鋼のスラグによる再酸化
が防止可能であるとの知見を得た。From the above, the necessary amount of Al for reducing slag is added to the molten steel deoxidized with Al, and then inert gas is blown into the molten steel to forcibly agitate the molten steel and the slag. Then, it was found that the iron oxide in the slag can be quickly and sufficiently reduced by the Al in the molten steel, and the reoxidation of the molten steel by the slag can be prevented.
【００１１】しかし、スラグを還元するために必要なＡ
ｌ量は、スラグ中のＴ．Ｆｅ濃度に依存しており、従っ
て、Ａｌを過剰に添加すればスラグ還元用に添加したＡ
ｌが溶鋼中に歩留まり、溶鋼中のＡｌ濃度の調整が困難
になり、一方、添加するＡｌが不足する場合にはスラグ
の還元が十分に行われない。そこで、溶鋼をＡｌにより
脱酸した後、その溶鋼上に存在するスラグのＴ．Ｆｅ濃
度を測定し、測定したＴ．Ｆｅ濃度に応じて添加する金
属Ａｌ量を決めれば、過不足なく金属Ａｌを添加するこ
とができるとの知見を得た。However, A required for reducing slag
l is determined by the T.L. It depends on the Fe concentration. Therefore, if Al is added excessively, A added for slag reduction is added.
1 yields in the molten steel, making it difficult to adjust the Al concentration in the molten steel. On the other hand, if the amount of Al added is insufficient, the slag is not sufficiently reduced. Therefore, after the molten steel is deoxidized with Al, the T.V. of the slag existing on the molten steel is reduced. Fe concentration was measured, and the measured T.F. It has been found that if the amount of metal Al to be added is determined according to the Fe concentration, metal Al can be added without excess or deficiency.
【００１２】本発明は、これらの知見に基づきなされた
もので、第１の発明による清浄鋼の製造方法は、溶鋼を
Ａｌにより脱酸した後、この溶鋼上に存在するスラグの
Ｔ．Ｆｅ濃度を測定し、測定したＴ．Ｆｅ濃度と溶鋼上
に存在するスラグ量とで算出される下記の（１）を満足
する範囲のＡｌを溶鋼へ添加し、次いで、不活性ガス吹
き込みにより溶鋼とスラグとを攪拌することを特徴とす
るものである。The present invention has been made based on these findings. The method for producing clean steel according to the first aspect of the present invention provides a method for deoxidizing molten steel with Al, and then removing T.S. of slag existing on the molten steel. Fe concentration was measured, and the measured T.F. It is characterized in that Al in a range satisfying the following (1) calculated from the Fe concentration and the amount of slag existing on the molten steel is added to the molten steel, and then the molten steel and the slag are stirred by blowing an inert gas. Is what you do.
【００１３】 (%T.Fe)Ws/400 ≦QAl≦ (%T.Fe)Ws/300……（１） 但し、（１）式において、（%T.Fe）はスラグ中のＴ．
Ｆｅ濃度（質量％）、Wsは溶鋼上に存在するスラグ量
（kg/ton-steel）、QAlはＡｌ添加量（kg/ton-steel）
を表すものである。(% T.Fe) Ws / 400 ≦ Q Al ≦ (% T.Fe) Ws / 300 (1) However, in the equation (1), (% T.Fe) represents T.F.
Fe concentration (% by mass), Ws is the amount of slag present on molten steel (kg / ton-steel), Q Al is the amount of Al added (kg / ton-steel)
Is represented.
【００１４】第２の発明による清浄鋼の製造方法は、第
１の発明による清浄鋼の製造方法をＲＨ真空脱ガス装置
を用いて実施し、不活性ガス吹き込みによる溶鋼とスラ
グとの攪拌後に、ＲＨ真空脱ガス装置の真空槽と溶鋼保
持容器との間で溶鋼を環流させることを特徴とするもの
である。[0014] The method for producing clean steel according to the second invention is a method for producing clean steel according to the first invention using an RH vacuum degassing apparatus. After stirring the molten steel and slag by blowing inert gas, The present invention is characterized in that molten steel is circulated between a vacuum tank of a RH vacuum degassing apparatus and a molten steel holding vessel.
【００１５】第３の発明による清浄鋼の製造方法は、第
１の発明又は第２の発明において、固体電解質を用いた
酸素センサーにより、スラグのＴ．Ｆｅ濃度を測定する
ことを特徴とするものである。The method for producing clean steel according to the third aspect of the present invention is the method according to the first or second aspect, wherein the oxygen sensor using a solid electrolyte is used to produce T.G. It is characterized by measuring the Fe concentration.
【００１６】スラグ中の鉄酸化物をＡｌにより還元する
反応は、下記の（２）式に示すように、３個のＦｅ原子
と２個のＡｌ原子とが反応して還元反応が行われる。In the reaction of reducing the iron oxide in the slag with Al, as shown in the following formula (2), three Fe atoms and two Al atoms react to perform a reduction reaction.
【００１７】3FeO + 2Al → 3Fe + 2Al2O3……（２） 従って、スラグ中の全ての鉄酸化物をＡｌにより還元す
る場合には、スラグ中のＴ．Ｆｅ濃度（質量％）と、溶
鋼上に存在するスラグ量Ｗｓ（kg/ton-steel）と、スラ
グ還元用のＡｌ添加量ＱAl（kg/ton-steel）との間に
は、Ｆｅ及びＡｌの原子量から化学量論的に下記の
（３）式が成立する。尚、（３）式の左辺はスラグ中の
酸素量と添加するＡｌ量との比を表している。[0017] 3FeO + 2Al → 3Fe + 2Al 2 O 3 ...... (2) Therefore, all of the iron oxide in the slag in the case of reduction by the Al is, T. in the slag Between the Fe concentration (mass%), the slag amount Ws (kg / ton-steel) existing on the molten steel, and the Al addition amount Q Al (kg / ton-steel) for slag reduction, Fe and Al The following equation (3) holds stoichiometrically from the atomic weight of The left side of the equation (3) represents the ratio between the amount of oxygen in the slag and the amount of Al added.
【００１８】(%T.Fe)Ws / QAl ＝ 310……（３） それ故、（３）式の左辺に示す［（％Ｔ．Ｆｅ）Ｗｓ／
ＱAl］の比（以下「酸素／Ａｌ比」と記す）が３１０を
越える場合には、添加するＡｌが不足する状態を表し、
一方、酸素／Ａｌ比が３１０よりも小さくなる場合に
は、添加するＡｌが過剰である状態を表すことになる。[0018] (% T.Fe) Ws / Q Al = 310 ...... (3) Therefore, shown in the left side of the equation (3) [(% T.Fe) Ws /
When the ratio of Q Al ] (hereinafter referred to as “oxygen / Al ratio”) exceeds 310, it indicates a state in which Al to be added is insufficient,
On the other hand, when the oxygen / Al ratio becomes smaller than 310, it indicates a state where the added Al is excessive.
【００１９】そこで、Ａｌ脱酸された溶鋼上に存在する
スラグのＴ．Ｆｅ濃度及びスラグの質量を測定すると共
に、スラグ還元用のＡｌ添加量を種々変更して酸素／Ａ
ｌ比を変更し、薄鋼板における酸化物系介在物による欠
陥発生率に及ぼす酸素／Ａｌ比の影響を調査した。Therefore, the slag existing on the Al-deoxidized molten steel has a T.I. The Fe concentration and the mass of the slag were measured and the oxygen / A
The l ratio was changed, and the effect of the oxygen / Al ratio on the defect generation rate due to oxide inclusions in the thin steel sheet was investigated.
【００２０】その結果、酸素／Ａｌ比が大きくなるほど
薄鋼板における欠陥発生率は増加するが、酸素／Ａｌ比
が４００以下であれば、スラグによる溶鋼の再酸化は清
浄性への影響がほとんどないレベルまで低減し、欠陥発
生率は目標とする範囲に収まることが分かった。一方、
酸素／Ａｌ比が３００未満では、溶鋼の清浄性の改善効
果は飽和して変わらずに、過剰に添加されるＡｌが無駄
になると共に、溶鋼のＡｌ濃度が増加して成分規格を越
える場合が発生することが分かった。Ａｌは高価であ
り、酸素／Ａｌ比が３００未満の過剰のＡｌ添加は製造
コストの上昇を招くのみである。As a result, as the oxygen / Al ratio increases, the defect generation rate in the thin steel sheet increases, but if the oxygen / Al ratio is 400 or less, the reoxidation of the molten steel by the slag has almost no effect on cleanliness. It was found that the defect occurrence rate fell to the target range. on the other hand,
If the oxygen / Al ratio is less than 300, the effect of improving the cleanliness of the molten steel is saturated and unchanged, and excessively added Al is wasted, and the Al concentration of the molten steel increases to exceed the component specification. It was found to happen. Al is expensive, and excessive addition of Al having an oxygen / Al ratio of less than 300 only causes an increase in manufacturing cost.
【００２１】従って、本発明では酸素／Ａｌ比が３００
〜４００の範囲となるように、即ち、上記の（１）式を
満足する範囲でスラグ還元用のＡｌ添加量を設定するこ
とにした。Therefore, in the present invention, the oxygen / Al ratio is 300
The amount of Al added for slag reduction was set so as to fall within the range of ４００400, that is, in a range satisfying the above equation (1).
【００２２】その際、還元用Ａｌ添加後に行う、溶鋼へ
の不活性ガス吹き込みによる溶鋼とスラグとの攪拌は、
ＲＨ真空脱ガス装置における精錬中に行うことが好まし
い。ＲＨ真空脱ガス装置における精錬では、取鍋と真空
槽との間を環流する溶鋼流により溶鋼は激しく攪拌され
ているため、スラグ還元により生成したＡｌ2 Ｏ3 の浮
上分離が促進され、溶鋼の清浄性を迅速に高めることが
できる。At this time, stirring of the molten steel and the slag by blowing the inert gas into the molten steel, which is performed after the addition of the reducing Al,
It is preferable to carry out during refining in the RH vacuum degassing apparatus. In the refining in the RH vacuum degassing apparatus, since the molten steel is vigorously stirred by the molten steel flow circulating between the ladle and the vacuum tank, the floating separation of Al 2 O 3 generated by slag reduction is promoted, and the molten steel is separated. The cleanliness can be quickly increased.
【００２３】又、スラグのＴ．Ｆｅ濃度の測定は、オン
ラインでの迅速測定が可能であるので、固体電解質を用
いた酸素センサーにより行うことが好ましい。The slag T.V. The measurement of the Fe concentration is preferably performed by an oxygen sensor using a solid electrolyte since rapid measurement can be performed online.
【００２４】[0024]
【発明の実施の形態】以下、本発明を添付図面を参照し
て説明する。図１は、本発明で用いたＲＨ真空脱ガス装
置の縦断面概略図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus used in the present invention.
【００２５】図１に示すように、ＲＨ真空脱ガス装置１
は、上部槽６及び下部槽７からなる真空槽５と、下部槽
７の下部に設けられた上昇側浸漬管８及び下降側浸漬管
９とで、その主たる設備が構成されており、上部槽６に
は、真空槽５内に合金やフラックス等の原料を供給する
ための原料投入口１１と、排気装置（図示せず）と接続
し、真空槽５内を排気する際のガス排出流路となるダク
ト１２とが設けられ、又、上昇側浸漬管８にはＡｒ吹き
込み管１０が設けられている。Ａｒ吹き込み管１０から
は環流用Ａｒが上昇側浸漬管８内に吹き込まれる構造と
なっている。As shown in FIG. 1, an RH vacuum degassing apparatus 1
The main equipment is composed of a vacuum tank 5 comprising an upper tank 6 and a lower tank 7, and an ascending-side immersion pipe 8 and a descending-side immersion pipe 9 provided below the lower tank 7. 6 is connected to a material inlet 11 for supplying a material such as an alloy or a flux into the vacuum chamber 5 and an exhaust device (not shown), and a gas exhaust passage for evacuating the vacuum chamber 5. And an Ar blowing pipe 10 is provided in the rising side immersion pipe 8. The Ar blowing pipe 10 has a structure in which Ar for reflux is blown into the rising side immersion pipe 8.
【００２６】更に、真空槽５の側壁と取鍋２との間隙を
昇降し、取鍋２内の溶鋼３に浸漬可能なランス１３が設
置されており、ランス１３からはＡｒや窒素等の不活性
ガスが溶鋼３中に吹き込まれる構造となっている。Further, a lance 13 is set up and down the gap between the side wall of the vacuum chamber 5 and the ladle 2 and can be immersed in the molten steel 3 in the ladle 2. The active gas is blown into the molten steel 3.
【００２７】このような構成のＲＨ真空脱ガス装置１に
おける本発明の適用方法を以下に説明する。先ず、転炉
や電気炉等で精錬して溶鋼３を得て、取鍋２に出鋼し、
溶鋼３を収納する取鍋２を真空槽５の直下に搬送する。
取鍋２内には転炉や電気炉での精錬で発生したスラグ４
が一部混入し、溶鋼３の湯面を覆っている。An application method of the present invention in the RH vacuum degassing apparatus 1 having such a configuration will be described below. First, it is refined in a converter or an electric furnace, etc. to obtain molten steel 3, and then put out to ladle 2,
The ladle 2 containing the molten steel 3 is transported directly below the vacuum tank 5.
Ladle 2 contains slag 4 generated by refining in a converter or electric furnace.
Is partially mixed and covers the molten metal surface of the molten steel 3.
【００２８】次いで、昇降装置（図示せず）にて取鍋２
を上昇させ、上昇側浸漬管８及び下降側浸漬管９を取鍋
２内の溶鋼３に浸漬させる。そして、Ａｒ吹き込み管１
０から上昇側浸漬管８内にＡｒを吹き込むと共に、真空
槽５内を排気装置にて排気して真空槽５内を減圧する。
真空槽５内が減圧されると、取鍋２内の溶鋼３は、Ａｒ
吹き込み管１０から吹き込まれるＡｒと共に上昇側浸漬
管８を上昇して真空槽５内に流入し、その後、下降側浸
漬管９を介して取鍋２に戻る流れ、所謂、環流を形成し
てＲＨ真空脱ガス精錬が施される。Next, the ladle 2 is moved by a lifting device (not shown).
Is raised, and the ascending-side immersion pipe 8 and the descending-side immersion pipe 9 are immersed in the molten steel 3 in the ladle 2. And Ar blowing pipe 1
Ar is blown into the rising side immersion pipe 8 from 0, and the inside of the vacuum tank 5 is depressurized by evacuating the inside of the vacuum tank 5 with an exhaust device.
When the pressure in the vacuum tank 5 is reduced, the molten steel 3 in the ladle 2
With the Ar blown from the blowing pipe 10, the rising side immersion pipe 8 rises and flows into the vacuum tank 5 and then returns to the ladle 2 via the descending side immersion pipe 9, forming a so-called reflux and RH. Vacuum degassing refining is performed.
【００２９】真空脱炭処理のような、溶鋼３が未脱酸の
状態で行うことが必要な精錬を最初に施した後、原料投
入口１１を介して溶鋼３に金属ＡｌやＡｌ−Ｆｅ合金等
を添加し、溶鋼３をＡｌにより脱酸する。この場合の金
属ＡｌやＡｌ−Ｆｅ合金等の投入量は、溶鋼３中の溶解
酸素を脱酸するために必要な量と製品成分規格を満足す
るために必要な量との合計量を添加する。溶鋼３中の溶
解酸素量は、例えば固体電解質を用いた酸素センサー等
により測定することができるが、操業条件に基づく経験
から推定しても良い。After first performing a refining such as a vacuum decarburization treatment that requires the molten steel 3 to be in a non-deoxidized state, the molten steel 3 is added to the molten steel 3 through the material input port 11 by using a metal Al or an Al—Fe alloy. The molten steel 3 is deoxidized with Al. In this case, the input amount of the metal Al, the Al—Fe alloy, or the like is the total amount of the amount necessary for deoxidizing the dissolved oxygen in the molten steel 3 and the amount necessary for satisfying the product component standard. . The amount of dissolved oxygen in the molten steel 3 can be measured by, for example, an oxygen sensor using a solid electrolyte, or may be estimated from experience based on operating conditions.
【００３０】一方、溶鋼３がＲＨ真空脱ガス装置１にお
ける精錬の前に脱酸されており、未脱酸の状態で処理す
る必要がない場合には、溶鋼３のＡｌ濃度を測定又は推
定し、必要ならば、製品成分規格を満足するために必要
な量の金属ＡｌやＡｌ−Ｆｅ合金等を、原料投入口１１
を介して溶鋼３に添加する。溶鋼３中のＡｌ濃度は、溶
鋼３から採取した分析用試料等から測定することや、溶
鋼用酸素センサー等にて測定する溶鋼中の酸素活量から
推定することができる。On the other hand, if the molten steel 3 has been deoxidized before refining in the RH vacuum degassing apparatus 1 and it is not necessary to treat it in an undeoxidized state, the Al concentration of the molten steel 3 is measured or estimated. If necessary, a necessary amount of metal Al or Al—Fe alloy or the like to satisfy the product component standard is supplied to the raw material inlet 11.
To molten steel 3 through The Al concentration in the molten steel 3 can be measured from an analysis sample or the like collected from the molten steel 3 or can be estimated from the oxygen activity in the molten steel measured by an oxygen sensor for molten steel or the like.
【００３１】このようにして、金属ＡｌやＡｌ−Ｆｅ合
金等の添加により溶鋼３がＡｌにより脱酸されたなら、
スラグ４中のＴ．Ｆｅ濃度（％Ｔ．Ｆｅ）を測定する。
前述したように、Ｔ．Ｆｅ濃度の測定には固体電解質を
用いた酸素センサーを用いることが好ましい。この場
合、酸素センサーによりスラグ４の酸素ポテンシャルを
測定し、酸素ポテンシャルとＴ．Ｆｅ濃度との検量線を
予め作成しておくことで、瞬時にスラグ４のＴ．Ｆｅ濃
度を測定することができる。In this way, if the molten steel 3 is deoxidized by Al by adding metal Al, Al—Fe alloy, or the like,
T. in slag 4 The Fe concentration (% T.Fe) is measured.
As described above, T.A. For the measurement of the Fe concentration, it is preferable to use an oxygen sensor using a solid electrolyte. In this case, the oxygen potential of the slag 4 is measured by an oxygen sensor, and the oxygen potential and T.V. By preparing a calibration curve with the Fe concentration in advance, the T.T. The Fe concentration can be measured.
【００３２】又、取鍋２内のスラグ４の質量を測定す
る。スラグ４の質量は、スラグ４の厚みの測定又は溶鋼
３を覆うスラグ４の面積率の目視測定等により測定する
ことができる。取鍋２内に収容された溶鋼量から、溶鋼
トン当たりのスラグ量（Ｗｓ）を求める。尚、スラグ４
の質量測定は、Ａｌ脱酸後に行う必然性はなく、Ａｌ脱
酸の前に予め測定しても良い。又、溶鋼量は転炉等から
取鍋への出鋼時に取鍋を秤量することで把握できる。Further, the mass of the slag 4 in the ladle 2 is measured. The mass of the slag 4 can be measured by measuring the thickness of the slag 4 or visually measuring the area ratio of the slag 4 covering the molten steel 3. From the amount of molten steel stored in the ladle 2, the amount of slag per ton of molten steel (Ws) is determined. In addition, slag 4
Is not necessarily performed after Al deoxidation, but may be measured in advance before Al deoxidation. The amount of molten steel can be grasped by weighing the ladle when tapping the ladle from the converter or the like.
【００３３】このようにして測定したスラグ４のＴ．Ｆ
ｅ濃度（％Ｔ．Ｆｅ）とスラグ量（Ｗｓ）とを前述の
（１）式に代入し、スラグ４の還元に必要なＡｌの添加
量（Ｑ Al）の範囲を設定する。そして、（１）式の範囲
内の任意のＡｌ添加量（ＱAl）を決め、決定した添加量
（ＱAl）に基づき金属ＡｌやＡｌ−Ｆｅ合金等をスラグ
４の還元用として原料投入口１１から溶鋼３に添加す
る。その際、金属ＡｌやＡｌ−Ｆｅ合金等のＡｌ含有量
に応じて、添加するＡｌ純分量が決定した添加量
（ＱAl）と等しくなるようにする。The TG of the slag 4 measured in this way was F
e concentration (% T.Fe) and slag amount (Ws)
Substituting into equation (1) and adding Al necessary for reduction of slag 4
Quantity (Q Al) Range. And the range of equation (1)
Any amount of Al (QAl) Is determined and the determined amount of addition
(QAlSlag based on metal Al or Al-Fe alloy
4 is added to the molten steel 3 through the material input port 11 for reduction.
You. At that time, the Al content of metallic Al and Al-Fe alloy
The amount of Al to be added is determined according to
(QAl).
【００３４】スラグ還元用Ａｌの添加に前後して、溶鋼
３に浸漬させたランス１３から不活性ガスを吹き込み、
溶鋼３とスラグ４とを強制的に攪拌する。この攪拌によ
り、溶鋼３中のＡｌとスラグ４中の鉄酸化物との反応が
起こり、スラグ４中のＴ．Ｆｅ濃度は３％以下まで低下
し、それ以降のスラグ４による溶鋼３の再酸化を抑制す
ることができる。この攪拌は、上昇側浸漬管８及び下降
側浸漬管９を溶鋼３より引き上げてから行うことが操業
面からは操作し易い。Before and after the addition of Al for reducing slag, an inert gas is blown from a lance 13 immersed in molten steel 3,
The molten steel 3 and the slag 4 are forcibly stirred. By this stirring, a reaction between Al in the molten steel 3 and iron oxide in the slag 4 occurs, and T.O. The Fe concentration is reduced to 3% or less, and reoxidation of the molten steel 3 by the slag 4 thereafter can be suppressed. It is easy to operate the stirring from the operation point of view after raising the rising side immersion pipe 8 and the descending side immersion pipe 9 from the molten steel 3.
【００３５】ランス１３からの不活性ガス吹き込み終了
後、発生したＡｌ2 Ｏ3 を浮上・分離させるために、溶
鋼３を数分間程度環流させることが好ましい。尚、Ｃ、
Ｓｉ、Ｍｎ等の成分を調整する必要がある場合には、こ
の環流時に同時に行えば良い。その後、真空槽５を大気
圧に戻してＲＨ真空脱ガス精錬を終了し、次工程の連続
鋳造設備や普通造塊設備等の鋳造設備に取鍋２を搬出し
て溶鋼３を鋳造する。After the blowing of the inert gas from the lance 13, the molten steel 3 is preferably refluxed for several minutes in order to float and separate the generated Al 2 O 3 . In addition, C,
When it is necessary to adjust components such as Si and Mn, the adjustment may be performed at the time of the reflux. Thereafter, the vacuum tank 5 is returned to the atmospheric pressure to complete the RH vacuum degassing refining, and the ladle 2 is carried out to a casting facility such as a continuous casting facility or a normal ingot making facility in the next step to cast the molten steel 3.
【００３６】このようにして溶鋼３及びスラグ４を処理
することで、溶鋼３に過剰なＡｌを添加することなく、
スラグ４のＴ．Ｆｅ濃度を迅速に且つ安定して低くする
ことができ、その結果、溶鋼３のスラグ４による再酸化
が抑制され、酸化物系介在物が極めて少ない高清浄鋼を
安定して製造することが可能となる。By treating the molten steel 3 and the slag 4 in this manner, without adding excessive Al to the molten steel 3,
T. of slag 4 The Fe concentration can be reduced promptly and stably. As a result, reoxidation of the molten steel 3 by the slag 4 is suppressed, and it is possible to stably produce a high-purity steel with very few oxide-based inclusions. Becomes
【００３７】尚、上記説明ではＲＨ真空脱ガス装置１を
用いて本発明を実施したが、本発明はこれに限るもので
はなく、取鍋２内に収容された溶鋼３に金属ＡｌやＡｌ
−Ｆｅ合金等を添加する設備と、取鍋２内に収容された
溶鋼３とスラグ４とを不活性ガス吹き込みにより攪拌す
る設備があれば、どのような設備であっても本発明を実
施することができる。In the above description, the present invention was implemented using the RH vacuum degassing apparatus 1. However, the present invention is not limited to this, and the molten steel 3 accommodated in the ladle 2 contains metal Al or Al.
The present invention is implemented in any equipment as long as there is equipment for adding an Fe alloy or the like and equipment for stirring the molten steel 3 and the slag 4 contained in the ladle 2 by blowing inert gas. be able to.
【００３８】[0038]
【実施例】炭素濃度が０．０２〜０．０６質量％である
約２５０トンの溶鋼を転炉から取鍋に未脱酸状態のまま
出鋼し、図１に示すＲＨ真空脱ガス装置に搬送して精錬
した。ＲＨ真空脱ガス装置では、先ず真空脱炭処理し、
次いで、溶鋼中の溶解酸素量を酸素センサーで測定し
て、溶解酸素を脱酸するために必要な金属Ａｌ量と製品
成分規格（０．０２〜０．０４質量％）を満足するため
に必要な金属Ａｌ量との合計量を添加した。EXAMPLE About 250 tons of molten steel having a carbon concentration of 0.02 to 0.06% by mass is tapped from a converter to a ladle in a non-deoxidized state, and is then supplied to an RH vacuum degassing apparatus shown in FIG. Transported and refined. In the RH vacuum degassing device, first, vacuum decarburization treatment is performed,
Next, the amount of dissolved oxygen in the molten steel is measured by an oxygen sensor, and the amount of metallic Al required for deoxidizing the dissolved oxygen and the product component standard (0.02 to 0.04 mass%) are required to be satisfied. And the total amount of metallic Al was added.
【００３９】その後、環流用Ａｒ流量を３０００Ｎｌ／
ｍｉｎ、真空槽内の圧力を６６〜２６６Ｐａ（０．５〜
２ｔｏｒｒ）の状態に維持したまま、取鍋の周方向４箇
所に設置したランスを取鍋内の溶鋼に浸漬させ、これら
のランスからＡｒを吹き込んで溶鋼とスラグとを攪拌し
つつ、スラグ還元用の金属Ａｌを溶鋼に添加した。その
際、取鍋内のスラグのＴ．Ｆｅ濃度を酸素センサーによ
り測定し、酸素／Ａｌ比が２８０〜４４０の範囲となる
ように金属Ａｌ量を調整して添加し、溶鋼の清浄性に及
ぼす酸素／Ａｌ比の影響を調査した。取鍋内のスラグ量
（Ｗｓ）は全ての試験において８kg/ton-steelに調整し
た。取鍋内スラグの組成はＣａＯ−ＳｉＯ2 −Ａｌ2 Ｏ
3 −ＭｇＯ系であった。Thereafter, the reflux Ar flow rate was increased to 3000 Nl /
min, the pressure in the vacuum chamber is 66 to 266 Pa (0.5 to
2 torr), the lances installed at four places in the circumferential direction of the ladle are immersed in the molten steel in the ladle, and Ar is blown from these lances to agitate the molten steel and the slag to reduce the slag. Was added to molten steel. At that time, T. of slag in ladle The Fe concentration was measured by an oxygen sensor, the amount of metallic Al was adjusted and added so that the oxygen / Al ratio was in the range of 280 to 440, and the effect of the oxygen / Al ratio on the cleanliness of molten steel was investigated. The amount of slag (Ws) in the ladle was adjusted to 8 kg / ton-steel in all tests. The composition of the ladle slag CaO-SiO 2 -Al 2 O
It was a 3- MgO system.
【００４０】スラグ還元用金属Ａｌの投入後、約２分間
ランスによる溶鋼とスラグとの攪拌を続け、ランスから
のＡｒ吹き込みの停止後、更に１分間溶鋼を環流させて
ＲＨ真空脱ガス装置による精錬を終了した。この環流
中、必要に応じて溶鋼の成分調整を行った。以下、この
精錬方法を製法１と呼ぶ。After the metal Al for slag reduction is charged, stirring of the molten steel and the slag by the lance is continued for about 2 minutes, and after the Ar blowing from the lance is stopped, the molten steel is refluxed for another minute and refined by the RH vacuum degassing apparatus. Finished. During this reflux, the components of the molten steel were adjusted as needed. Hereinafter, this refining method is referred to as Production Method 1.
【００４１】その後、連続鋳造機にてスラブ鋳片に鋳造
し、熱間圧延及び冷間圧延を経て、薄鋼板製品とし、薄
鋼板製品における酸化物系介在物による表面欠陥の発生
率を調査した。溶鋼の清浄性は、この表面欠陥の発生率
を指数化した製品欠陥指数で評価した。製品欠陥指数が
低いほど、清浄性が高いことを表しており、本発明では
製品欠陥指数が０．５以下を清浄性に優れると評価し
た。Thereafter, the slab was cast into a slab slab using a continuous casting machine, subjected to hot rolling and cold rolling to form a thin steel sheet product, and the incidence of surface defects due to oxide-based inclusions in the thin steel sheet article was investigated. . The cleanliness of the molten steel was evaluated by a product defect index obtained by indexing the occurrence rate of the surface defects. The lower the product defect index, the higher the cleanability. In the present invention, a product defect index of 0.5 or less was evaluated as excellent in cleanability.
【００４２】又、比較のために、転炉出鋼直後にスラグ
還元用の金属Ａｌを取鍋内のスラグ上に添加し、その
後、ＲＨ真空脱ガス装置にて真空脱炭処理し、次いで金
属Ａｌを添加して溶鋼を脱酸する方法、即ち、溶鋼とス
ラグとを強制的に攪拌することなく単に転炉出鋼直後に
金属Ａｌをスラグ上に添加する方法（製法２と呼ぶ）で
製造した鋳片も薄鋼板に圧延し、薄鋼板製品における酸
化物系介在物による表面欠陥の発生率を調査した。For comparison, metal Al for slag reduction was added to the slag in the ladle immediately after the start of the converter, and then vacuum decarburization treatment was performed using an RH vacuum degasser. Manufactured by a method of adding Al to deoxidize molten steel, that is, a method of simply adding metal Al onto slag immediately after converter tapping without forcibly stirring the molten steel and slag (referred to as manufacturing method 2). The cast slabs were also rolled into thin steel sheets, and the incidence of surface defects due to oxide-based inclusions in thin steel sheet products was investigated.
【００４３】更に、ＲＨ真空脱ガス装置におけるＡｌに
よる溶鋼の脱酸までは製法１と同一な方法で精錬し、溶
鋼の脱酸後にスラグ還元用の金属Ａｌを取鍋内のスラグ
上に添加するのみとし、溶鋼とスラグとを強制的に攪拌
することなく製造する方法（製法３と呼ぶ）で製造した
鋳片も薄鋼板に圧延し、薄鋼板製品における酸化物系介
在物による表面欠陥の発生率を調査した。Further, the molten steel is refined in the same manner as in Production Method 1 up to the deoxidation of molten steel by Al in the RH vacuum degassing apparatus, and after the molten steel is deoxidized, metal Al for slag reduction is added to the slag in the ladle. A slab produced by a method of producing molten steel and slag without forcible stirring (referred to as production method 3) is also rolled into a thin steel sheet, and surface defects due to oxide inclusions in the thin steel sheet product are generated. The rates were investigated.
【００４４】表１に各試験における試験条件及び試験結
果を示し、又、図２に酸素／Ａｌ比と製品欠陥指数との
関係を製法１、製法２、及び製法３で分別して示す。Table 1 shows the test conditions and test results in each test, and FIG. 2 shows the relationship between the oxygen / Al ratio and the product defect index separately for Production Method 1, Production Method 2, and Production Method 3.
【００４５】[0045]
【表１】 [Table 1]
【００４６】表１及び図２に示すように、製法１で製造
した薄鋼板においても酸素／Ａｌ比が４００を越える
と、製品欠陥指数が０．５を越えて清浄性が劣化するこ
とが分かった。又、酸素／Ａｌ比が３００未満になる
と、製品欠陥指数は低く、清浄性の点からは全く問題な
かったが、溶鋼のＡｌ濃度が増加するので成分調整に配
慮する必要があった。酸素／Ａｌ比が３００〜４００の
範囲では清浄性が高く、又、溶鋼のＡｌ濃度を調整する
必要が全くなかった。一方、製法２及び製法３で製造し
た薄鋼板では、酸素／Ａｌ比の値に関わらず製品欠陥指
数が高く、清浄性が良いとは必ずしも云えなかった。
尚、表１の備考欄には、本発明の範囲内で製造した試験
は実施例と表示し、製法１による製造方法でも金属Ａｌ
の添加量が本発明の範囲を外れた試験は比較例と表示
し、製法２及び製法３により製造した試験は従来例と表
示した。As shown in Table 1 and FIG. 2, when the oxygen / Al ratio exceeds 400, the product defect index exceeds 0.5 and the cleanliness deteriorates even in the thin steel sheet manufactured by the manufacturing method 1. Was. When the oxygen / Al ratio is less than 300, the product defect index is low and there is no problem from the viewpoint of cleanliness. However, since the Al concentration of the molten steel increases, it is necessary to consider the component adjustment. When the oxygen / Al ratio was in the range of 300 to 400, cleanliness was high, and there was no need to adjust the Al concentration of the molten steel. On the other hand, the thin steel sheets produced by Production Method 2 and Production Method 3 had a high product defect index regardless of the value of the oxygen / Al ratio, and did not necessarily have good cleanliness.
In the remarks column of Table 1, the tests manufactured within the scope of the present invention are indicated as Examples, and the metal Al
The test in which the amount of added was out of the range of the present invention was designated as Comparative Example, and the test produced by Production Method 2 and Production Method 3 was designated as Conventional Example.
【００４７】[0047]
【発明の効果】本発明によれば、スラグ還元用Ａｌをス
ラグ中のＴ．Ｆｅ濃度に応じて添加し、且つ、スラグ還
元用Ａｌの添加後に溶鋼とスラグとを強制的に攪拌する
ので、溶鋼に過剰なＡｌを添加することなく、スラグの
Ｔ．Ｆｅ濃度を安定して低くすることができ、その結
果、溶鋼のスラグによる再酸化が抑制され、酸化物系介
在物が極めて少ない高清浄鋼を安定して製造することが
可能となり、工業上有益な効果がもたらされる。According to the present invention, Al for slag reduction is converted into T.S. Since the molten steel and the slag are forcibly stirred after the addition of Al for reducing slag, the molten steel and the slag are forcibly stirred without adding excessive Al to the molten steel. The Fe concentration can be stably reduced, and as a result, reoxidation of molten steel by slag is suppressed, and it becomes possible to stably produce high-purity steel with extremely few oxide-based inclusions, which is industrially beneficial. Effects are provided.
【図１】本発明で用いたＲＨ真空脱ガス装置の縦断面概
略図である。FIG. 1 is a schematic vertical sectional view of an RH vacuum degassing apparatus used in the present invention.
【図２】酸素／Ａｌ比と製品欠陥指数との関係を示す図
である。FIG. 2 is a diagram showing a relationship between an oxygen / Al ratio and a product defect index.
１ ＲＨ真空脱ガス装置 ２ 取鍋 ３ 溶鋼 ４ スラグ ５ 真空槽 ６ 上部槽 ７ 下部槽 ８ 上昇側浸漬管 ９ 下降側浸漬管 １０ Ａｒ吹き込み管 １１ 原料投入口 １２ ダクト １３ ランス DESCRIPTION OF SYMBOLS 1 RH vacuum degassing apparatus 2 Ladle 3 Molten steel 4 Slag 5 Vacuum tank 6 Upper tank 7 Lower tank 8 Upside immersion pipe 9 Downside immersion pipe 10 Ar blowing pipe 11 Raw material inlet 12 Duct 13 Lance
───────────────────────────────────────────────────── フロントページの続き (72)発明者 渡辺 敦 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 櫻井 栄司 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 Ｆターム(参考） 4K013 BA08 CA02 CA12 CA15 CB02 CC04 CE01 CF01 DA03 DA05 DA10 DA13 EA19 FA05 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Watanabe 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Eiji Sakurai 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Sun 4K013 BA08 CA02 CA12 CA15 CB02 CC04 CE01 CF01 DA03 DA05 DA10 DA13 EA19 FA05
Claims (3)
上に存在するスラグのＴ．Ｆｅ濃度を測定し、測定した
Ｔ．Ｆｅ濃度と溶鋼上に存在するスラグ量とで算出され
る下記の（１）を満足する範囲のＡｌを溶鋼へ添加し、
次いで、不活性ガス吹き込みにより溶鋼とスラグとを攪
拌することを特徴とする清浄鋼の製造方法。 (%T.Fe)Ws/400 ≦QAl≦ (%T.Fe)Ws/300……（１） 但し、（１）式において各符号は以下を表すものであ
る。 （%T.Fe）：スラグ中のＴ．Ｆｅ濃度（質量％） Ws：溶鋼上に存在するスラグ量（kg/ton-steel） QAl：Ａｌ添加量（kg/ton-steel）1. After the molten steel has been deoxidized with Al, the slag present on the molten steel has a T.I. Fe concentration was measured, and the measured T.F. Al in a range satisfying the following (1) calculated from the Fe concentration and the amount of slag existing on the molten steel is added to the molten steel,
Next, the molten steel and the slag are agitated by blowing an inert gas, thereby producing a clean steel. (% T.Fe) Ws / 400 ≦ Q Al ≦ (% T.Fe) Ws / 300 (1) where the symbols in the formula (1) represent the following. (% T.Fe): T. in slag. Fe concentration (mass%) Ws: amount of slag existing on molten steel (kg / ton-steel) Q Al : amount of Al added (kg / ton-steel)
Ｈ真空脱ガス装置を用いて実施し、不活性ガス吹き込み
による溶鋼とスラグとの攪拌後に、ＲＨ真空脱ガス装置
の真空槽と溶鋼保持容器との間で溶鋼を環流させること
を特徴とする清浄鋼の製造方法。2. The method for producing clean steel according to claim 1,
Cleaning using a H vacuum degassing apparatus, wherein after molten steel and slag are stirred by blowing inert gas, the molten steel is refluxed between a vacuum tank and a molten steel holding vessel of the RH vacuum degassing apparatus. Steel production method.
り、スラグのＴ．Ｆｅ濃度を測定することを特徴とする
請求項１又は請求項２に記載の清浄鋼の製造方法。3. The T.V. of slag is measured by an oxygen sensor using a solid electrolyte. The method for producing clean steel according to claim 1 or 2, wherein the Fe concentration is measured.
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|---|---|---|---|
| JP2000250727A JP3915386B2 (en) | 2000-08-22 | 2000-08-22 | Manufacturing method of clean steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000250727A JP3915386B2 (en) | 2000-08-22 | 2000-08-22 | Manufacturing method of clean steel |
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| Publication Number | Publication Date |
|---|---|
| JP2002060831A true JP2002060831A (en) | 2002-02-28 |
| JP3915386B2 JP3915386B2 (en) | 2007-05-16 |
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| Country | Link |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003041315A (en) * | 2001-07-31 | 2003-02-13 | Nkk Corp | Method for manufacturing high cleanliness steel |
| KR20030053142A (en) * | 2001-12-22 | 2003-06-28 | 주식회사 포스코 | Method for Manufacturing Ultra Carbon Steel with High Cleanliness |
| RU2517626C1 (en) * | 2013-01-09 | 2014-05-27 | Открытое акционерное общество "Северсталь" (ОАО "Северсталь") | Method of producing especially-low-carbon steel |
| RU2681961C1 (en) * | 2018-05-15 | 2019-03-14 | Публичное акционерное общество "Северсталь" (ПАО "Северсталь") | Method of producing extremely low-carbon steel |
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|---|---|---|---|---|
| RU2564205C1 (en) * | 2014-07-14 | 2015-09-27 | Публичное акционерное общество "Северсталь" (ПАО "Северсталь") | Method of producing especially-low-carbon steel |
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-
2000
- 2000-08-22 JP JP2000250727A patent/JP3915386B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003041315A (en) * | 2001-07-31 | 2003-02-13 | Nkk Corp | Method for manufacturing high cleanliness steel |
| KR20030053142A (en) * | 2001-12-22 | 2003-06-28 | 주식회사 포스코 | Method for Manufacturing Ultra Carbon Steel with High Cleanliness |
| RU2517626C1 (en) * | 2013-01-09 | 2014-05-27 | Открытое акционерное общество "Северсталь" (ОАО "Северсталь") | Method of producing especially-low-carbon steel |
| RU2681961C1 (en) * | 2018-05-15 | 2019-03-14 | Публичное акционерное общество "Северсталь" (ПАО "Северсталь") | Method of producing extremely low-carbon steel |
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| Publication number | Publication date |
|---|---|
| JP3915386B2 (en) | 2007-05-16 |
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