JPH11293329A - Production of extra-low carbon silicon-killed steel excellent in cleaning property - Google Patents
Production of extra-low carbon silicon-killed steel excellent in cleaning propertyInfo
- Publication number
- JPH11293329A JPH11293329A JP10094133A JP9413398A JPH11293329A JP H11293329 A JPH11293329 A JP H11293329A JP 10094133 A JP10094133 A JP 10094133A JP 9413398 A JP9413398 A JP 9413398A JP H11293329 A JPH11293329 A JP H11293329A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- flux
- steel
- low carbon
- weight
- 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.)
- Pending
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
- Y02P10/20—Recycling
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、転炉とＲＨ真空脱
ガス装置とを用い、酸化物が少なく、清浄性に優れた極
低炭素Ｓｉキルド鋼を安定して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 stably producing an ultra-low carbon Si killed steel having a small amount of oxides and excellent cleanliness by using a converter and an RH vacuum degassing apparatus. .
【０００２】[0002]
【従来の技術】鉄心材料に使用される電磁鋼板では、材
料の用途拡大、苛酷条件下での使用、及び材料の軽量化
等により、鉄損値や磁束密度等の磁気特性の向上に対す
る要求が年々高まっている。この磁気特性は材料の結晶
粒度と相関があり、結晶粒度が大きいほど優れるが、鋼
中には炭化物、窒化物、硫化物、酸化物等の介在物が存
在し、これらの介在物により結晶粒の成長が阻害される
ため、介在物の低減化対策が広く行われている。例え
ば、精錬工程では二次精錬炉による脱炭処理、脱窒処
理、及び、脱硫処理等が行なわれ、又、材料の成分設計
ではＴｉ、Ｖ、Ａｌ、Ｚｒ等の窒化物生成元素及び硫化
物生成元素を含有しない成分系とすることが行なわれ、
その結果、炭化物、窒化物、及び、硫化物は目的とする
水準まで低減可能となった。2. Description of the Related Art In electromagnetic steel sheets used for iron core materials, there is a demand for improvement of magnetic properties such as iron loss value and magnetic flux density due to expanded use of the materials, use under severe conditions, and weight reduction of the materials. It is growing year by year. The magnetic properties are correlated with the grain size of the material, and the larger the grain size, the better.However, inclusions such as carbides, nitrides, sulfides, and oxides are present in steel, and these inclusions cause the Therefore, measures for reducing inclusions have been widely adopted. For example, in the refining process, decarburization treatment, denitrification treatment, desulfurization treatment, etc. are performed in a secondary refining furnace. In the material component design, nitride-forming elements such as Ti, V, Al, and Zr and sulfides are used. A component system containing no generated element is performed,
As a result, carbides, nitrides, and sulfides can be reduced to target levels.
【０００３】しかし、酸化物の低減効果の大きいＡｌを
脱酸剤として使用できないため、Ａｌより酸素との親和
力の弱いＳｉ及びＭｎを脱酸剤として用いざるを得ず、
又、転炉からの出鋼時に転炉スラグが混入し、脱酸後の
鋳造中に、溶鋼中のＳｉ及びＭｎとスラグ中の鉄酸化物
とが反応してＳｉＯ2 やＭｎＯを溶鋼中に継続して生成
させるため、酸化物の含有量が多く、酸化物の低減が望
まれていた。However, since Al, which has a large oxide reducing effect, cannot be used as a deoxidizing agent, Si and Mn, which have a lower affinity for oxygen than Al, must be used as a deoxidizing agent.
In addition, converter slag is mixed during tapping from the converter, and during casting after deoxidation, Si and Mn in the molten steel react with iron oxide in the slag to convert SiO 2 and MnO into the molten steel. In order to continuously generate the oxide, the content of the oxide is large, and reduction of the oxide has been desired.
【０００４】又、Ｓｉ及びＭｎに代わる脱酸剤として、
特開平５−３０６４３７号公報ではＭｇを用いることを
提案しているが、Ｍｇは溶鋼への溶解度が小さく、又、
溶鋼温度では蒸気圧が高く、安定して十分な脱酸を行う
ことは極めて困難であり、且つ、脱酸剤としては高価で
あるという問題点を有している。[0004] As a deoxidizing agent in place of Si and Mn,
Japanese Patent Application Laid-Open No. Hei 5-306437 proposes to use Mg, but Mg has low solubility in molten steel, and
At the molten steel temperature, the vapor pressure is high, and it is extremely difficult to stably perform sufficient deoxidation, and there is a problem that it is expensive as a deoxidizing agent.
【０００５】[0005]
【発明が解決しようとする課題】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、転炉とＲ
Ｈ真空脱ガス装置とを用いて、電磁鋼板に代表される極
低炭素Ｓｉキルド鋼を製造する際に、酸化物が少なく、
清浄性の優れた極低炭素Ｓｉキルド鋼を安定して製造す
る方法を提供することである。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a purpose thereof is to provide a converter and an R converter.
When using an H vacuum degassing device to produce ultra-low carbon Si-killed steel typified by electrical steel sheets,
An object of the present invention is to provide a method for stably producing an ultra-low carbon Si killed steel having excellent cleanliness.
【０００６】[0006]
【課題を解決するための手段】本発明による清浄性に優
れた極低炭素Ｓｉキルド鋼の製造方法は、転炉で精錬し
た溶鋼をＲＨ真空脱ガス装置にて脱炭した後、Ｓｉ脱酸
して製造する極低炭素Ｓｉキルド鋼の製造方法におい
て、ＲＨ真空脱ガス装置での処理中に、ＣａＯを主体と
するフラックス中のＣａＯ純分重量（Ｂ）と処理する溶
鋼重量（Ａ）との関係が（１）式を満足するようにし
て、前記フラックスを溶鋼中に添加することを特徴とす
るものである。 ０．００１≦Ｂ／Ａ≦０．０１……（１）According to the present invention, there is provided a method for producing an ultra-low carbon Si-killed steel excellent in cleanliness, comprising the steps of: decarburizing molten steel refined in a converter with an RH vacuum degassing apparatus; In the method for producing ultra-low carbon Si killed steel, the weight of pure CaO in the flux mainly composed of CaO (B) and the weight of molten steel to be treated (A) during the treatment in the RH vacuum degassing apparatus The flux is added to the molten steel such that the relationship (1) satisfies the expression (1). 0.001 ≦ B / A ≦ 0.01 (1)
【０００７】本発明では、ＲＨ真空脱ガス装置での処理
中にＣａＯを主体とするフラックスを溶鋼中に添加す
る。ＣａＯを主体とするフラックスを用いる理由は、Ｃ
ａＯは酸素ポテンシャルが低く、そのため、ＣａＯを主
体とするフラックスは、Ｓｉ及びＭｎを含有するＳｉキ
ルド溶鋼と接触しても、新たに酸化物を生成させる酸素
源とならず、Ｓｉキルド鋼の清浄性を劣化しないからで
ある。In the present invention, a flux mainly composed of CaO is added to molten steel during the treatment in the RH vacuum degassing apparatus. The reason for using a flux mainly composed of CaO is as follows.
Since aO has a low oxygen potential, the flux mainly composed of CaO does not become a new oxygen source to generate an oxide even when it comes into contact with a Si-killed molten steel containing Si and Mn, so that the Si-killed steel is cleaned. This is because the properties are not deteriorated.
【０００８】そして、添加したフラックスは、その一部
が取鍋内の溶鋼上に浮遊するスラグと融合し、スラグの
鉄酸化物濃度を希釈する。その結果、スラグの酸素ポテ
ンシャルが下がり、スラグ中の鉄酸化物による溶鋼中の
Ｓｉ及びＭｎの酸化反応が抑制され、溶鋼中での新たな
酸化物の生成が阻止される。又、添加したフラックス
は、その一部が溶鋼とスラグとの界面に存在して溶鋼と
スラグとの接触を遮断し、溶鋼中のＳｉ及びＭｎのスラ
グによる酸化を阻止する。このため、溶鋼中の酸化物
は、増加することなく浮上分離して減少するので、溶鋼
の清浄性が向上する。[0008] A part of the added flux fuses with the slag floating on the molten steel in the ladle to dilute the iron oxide concentration of the slag. As a result, the oxygen potential of the slag decreases, and the oxidation reaction of Si and Mn in the molten steel by the iron oxide in the slag is suppressed, and the generation of new oxides in the molten steel is prevented. In addition, a part of the added flux is present at the interface between the molten steel and the slag to block the contact between the molten steel and the slag, and to prevent oxidation of Si and Mn in the molten steel by the slag. For this reason, the oxide in the molten steel floats and decreases without increasing, and the cleanliness of the molten steel is improved.
【０００９】このＣａＯを主体とするフラックスの添加
量は、処理する溶鋼重量をＡとし、フラックス中のＣａ
Ｏ純分重量をＢとした時、ＣａＯを主体とするフラック
ス中のＣａＯ純分重量（Ｂ）と処理する溶鋼重量（Ａ）
との比（Ａ／Ｂ）が、０．００１以上で０．０１以下の
範囲となるようにする。この比（Ａ／Ｂ）が０．００１
未満では、フラックスの添加量が不足して上記のフラッ
クス添加による効果が発揮できず、又、比（Ａ／Ｂ）が
０．０１を越えると、溶鋼中にフラックスが巻込まれて
酸化物が増加するからである。尚、本発明の極低炭素鋼
とは、炭素濃度が５０ｐｐｍ以下の鋼種の総称である。The amount of the flux mainly composed of CaO is defined as follows:
When the O pure content weight is B, the CaO pure content weight (B) in the flux mainly composed of CaO and the molten steel weight to be treated (A)
(A / B) in the range of 0.001 or more and 0.01 or less. This ratio (A / B) is 0.001
If the ratio is less than the above, the effect of the above-mentioned addition of the flux cannot be exerted due to the insufficient amount of the flux. If the ratio (A / B) exceeds 0.01, the flux is entrained in the molten steel and the oxide increases. Because you do. The ultra-low carbon steel of the present invention is a general term for steel types having a carbon concentration of 50 ppm or less.
【００１０】[0010]
【発明の実施の形態】以下、本発明を具体的に説明す
る。図１は本発明を実施したＲＨ真空脱ガス装置の縦断
面概略図であり、ＲＨ真空脱ガス装置１は、図１に示す
ように、上部槽７及び下部槽８からなる真空槽６と、下
部槽８の下部に設けた上昇側浸漬管９及び下降側浸漬管
１０と、フラックス５を収納するホッパー１５に接続
し、真空槽６の側壁外面に沿って上下移動の可能な吹き
込みランス１４とから構成されており、上部槽７には、
側壁を貫通する原料投入口１２と、排気装置（図示せ
ず）と連結するダクト１３とが設置され、又、上昇側浸
漬管９には、Ａｒガス吹き込み管１１が設置されてい
る。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. FIG. 1 is a schematic vertical cross-sectional view of an RH vacuum degassing device embodying the present invention. As shown in FIG. 1, the RH vacuum degassing device 1 includes a vacuum tank 6 including an upper tank 7 and a lower tank 8; A blowing lance 14 connected to an ascending-side immersion pipe 9 and a descending-side immersion pipe 10 provided at a lower portion of the lower tank 8 and a hopper 15 for storing the flux 5 and capable of moving up and down along the outer surface of the side wall of the vacuum tank 6; And the upper tank 7 includes:
A raw material inlet 12 penetrating the side wall and a duct 13 connected to an exhaust device (not shown) are provided, and an ascending side immersion pipe 9 is provided with an Ar gas blowing pipe 11.
【００１１】先ず、転炉（図示せず）にて溶銑を脱炭精
錬して溶鋼３を製造し、Ａｌ、Ｃａ、Ｔｉ、Ｚｒ等の強
脱酸剤を添加せずに未脱酸状態のままで溶鋼３を取鍋２
に出鋼する。次いで、ＲＨ真空脱ガス装置１に溶鋼３を
搬送する。この時、取鍋２内には出鋼時に転炉から排出
されたスラグ４が混入している。尚、出鋼時にＳｉ、Ｍ
ｎを添加しても材質上は問題ないが、溶鋼３中にＳｉ及
びＭｎが存在すると、次の脱炭処理での脱炭速度が遅く
なると同時に、脱炭処理時にＳｉ及びＭｎが酸化除去し
て歩留りが低下するので、Ｓｉ、Ｍｎも添加しない方が
良い。First, hot metal is decarburized and refined in a converter (not shown) to produce molten steel 3, which is not deoxidized without adding a strong deoxidizing agent such as Al, Ca, Ti and Zr. Ladle 2 with molten steel 3
To steel. Next, the molten steel 3 is transported to the RH vacuum degassing device 1. At this time, the slag 4 discharged from the converter at the time of tapping is mixed in the ladle 2. At the time of tapping, Si, M
Although there is no problem on the material even if n is added, if Si and Mn are present in the molten steel 3, the decarburization rate in the next decarburization process is reduced, and at the same time, Si and Mn are oxidized and removed during the decarburization process. Therefore, it is better not to add Si and Mn.
【００１２】ＲＨ真空脱ガス装置１では、真空槽６の直
下に取鍋２を搬入し、次いで、昇降機（図示せず）にて
取鍋２を上昇させ、上昇側浸漬管９及び下降側浸漬管１
０を取鍋２内の溶鋼３に浸漬させる。そして、Ａｒガス
吹き込み管１１から上昇側浸漬管９内にＡｒガスを吹き
込むと共に、真空槽６内を排気装置にて排気して真空槽
６内を減圧する。真空槽６内が減圧されると、取鍋２内
の溶鋼３は、Ａｒガス吹き込み管１１から吹き込まれる
Ａｒガスと共に上昇側浸漬管９を上昇して真空槽６内に
流入し、その後、下降側浸漬管１０を介して取鍋２に戻
る流れ、所謂、環流を形成して脱ガス処理が施される。In the RH vacuum degassing apparatus 1, the ladle 2 is carried in just below the vacuum tank 6, and then the ladle 2 is lifted by an elevator (not shown), and the ascending side dipping pipe 9 and the descending side dipping are carried out. Tube 1
0 is immersed in molten steel 3 in ladle 2. Then, Ar gas is blown into the rising side immersion pipe 9 from the Ar gas blowing pipe 11, and the inside of the vacuum chamber 6 is depressurized by evacuating the inside of the vacuum chamber 6 with an exhaust device. When the pressure in the vacuum chamber 6 is reduced, the molten steel 3 in the ladle 2 rises along the rising side immersion pipe 9 together with the Ar gas blown from the Ar gas blowing pipe 11 and flows into the vacuum tank 6, and then falls. A flow returning to the ladle 2 via the side immersion pipe 10, that is, a so-called reflux is formed and degassing is performed.
【００１３】先ず、脱炭処理を施すが、脱炭反応は未脱
酸状態の溶鋼３を真空槽６内に環流させることで行うこ
とができる。高真空下では、溶鋼３中の溶解酸素と炭素
との反応が進行し、溶鋼３が脱炭されるからである。First, a decarburization treatment is performed. The decarburization reaction can be performed by circulating the undeoxidized molten steel 3 into the vacuum chamber 6. This is because, under a high vacuum, the reaction between the dissolved oxygen in the molten steel 3 and the carbon proceeds, and the molten steel 3 is decarburized.
【００１４】脱炭反応により溶鋼３の炭素濃度が５０ｐ
ｐｍ以下の所定値になったら、原料投入口１２からＦｅ
−Ｓｉ合金、Ｓｉ−Ｍｎ合金等のＳｉ含有金属を添加し
て溶鋼３を脱酸する。Ｓｉ含有金属の添加量は、予め酸
素メーター（図示せず）等で溶鋼３中の溶解酸素濃度を
測定し、この溶解酸素と反応してＳｉＯ2 となるＳｉ量
と、鋼種により決まる所定量のＳｉ量が残留する量との
和に相当する量とする。The carbon concentration of the molten steel 3 is reduced to 50 p by the decarburization reaction.
pm or less, the material feed port 12
The molten steel 3 is deoxidized by adding a Si-containing metal such as a -Si alloy or a Si-Mn alloy. The addition amount of Si-containing metal in advance oxygen meter (not shown) to measure the dissolved oxygen concentration in the molten steel 3 in such a Si amount of the SiO 2 reacts with the dissolved oxygen, the predetermined amount determined by the steel type The Si amount is an amount corresponding to the sum of the remaining amount and the Si amount.
【００１５】そして、これらの脱炭処理の処理開始前か
らＳｉ添加後までの任意の時期に、吹き込みランス１４
を下降させて取鍋２内の溶鋼３中に浸漬し、吹き込みラ
ンス先端１４ａを上昇側浸漬管９の下方直下で停止し、
吹き込みランス１４から溶鋼３中にＣａＯを主体とする
フラックス５を、Ａｒガス等の不活性ガスを搬送ガスと
して吹き込む。フラックス５の添加量は、フラックス５
中のＣａＯ純分重量（Ｂ）と処理する溶鋼重量（Ａ）と
の関係が（１）式を満足するようにする。又、フラック
ス５は、ＣａＯを主体とするものであれば何でも良く、
例えば、生石灰、又は、生石灰に蛍石、珪石等を添加し
た混合物とする。 ０．００１≦Ｂ／Ａ≦０．０１……（１）At any time before the start of the decarburization treatment and after the addition of Si, the blowing lance 14
Is lowered and immersed in the molten steel 3 in the ladle 2, and the blowing lance tip 14a is stopped immediately below the rising side immersion pipe 9;
The flux 5 mainly composed of CaO is blown into the molten steel 3 from the blowing lance 14 using an inert gas such as an Ar gas as a carrier gas. The amount of flux 5 added is
The relationship between the CaO pure content weight (B) and the molten steel weight (A) to be treated is set so as to satisfy the expression (1). The flux 5 may be anything as long as it is mainly composed of CaO.
For example, quick lime or a mixture of quick lime and fluorite or silica stone is used. 0.001 ≦ B / A ≦ 0.01 (1)
【００１６】添加されたフラックス５は、溶鋼３と共に
真空槽６内を環流して下降側浸漬管１０から取鍋２内に
戻り、次いで、浮上して溶鋼３とスラグ４との界面に至
る。フラックス５は、これらの過程で溶鋼３から熱を受
けて一部溶融し、溶融したフラックス５はスラグ４と融
合してスラグ４の鉄酸化物濃度を希釈する。又、溶融し
ないフラックス５は、溶鋼３とスラグ４との界面に存在
して、溶鋼３とスラグ４とが直接接触することを妨げ
る。The added flux 5 circulates in the vacuum chamber 6 together with the molten steel 3, returns from the dipping pipe 10 into the ladle 2, and then floats to reach the interface between the molten steel 3 and the slag 4. The flux 5 receives heat from the molten steel 3 and partially melts in these processes, and the molten flux 5 fuses with the slag 4 to dilute the iron oxide concentration of the slag 4. The flux 5 that does not melt is present at the interface between the molten steel 3 and the slag 4 and prevents the molten steel 3 and the slag 4 from coming into direct contact.
【００１７】そして、所定量のフラックス５の添加後、
Ｓｉ、Ｍｎ、及び必要により他の成分を調整し、次い
で、真空槽６を大気圧に戻して脱ガス処理を終了し、次
工程の連続鋳造設備等の鋳造設備に溶鋼３を搬送して鋳
造する。After the addition of a predetermined amount of flux 5,
The Si, Mn, and other components are adjusted as necessary, then the vacuum chamber 6 is returned to atmospheric pressure to end the degassing process, and the molten steel 3 is transported to a casting facility such as a continuous casting facility in the next step to be cast. I do.
【００１８】このように溶鋼３を処理することにより、
介在物が少なく、清浄性に優れた極低炭素Ｓｉキルド鋼
を安定して製造することが可能となり、電磁鋼板におい
ては、磁気特性を高めることが可能となる。By treating the molten steel 3 in this way,
It is possible to stably produce an ultra-low carbon Si-killed steel having a small amount of inclusions and excellent cleanliness, and it is possible to enhance the magnetic properties of an electromagnetic steel sheet.
【００１９】尚、上記説明では、吹き込みランス１４に
てフラックス５を添加しているが、フラックス５の添加
方法はこれに限るものではなく、原料投入口１２から真
空槽６内の溶鋼３に添加しても良く、又、取鍋２の底部
に吹き込み羽口を設けてその羽口から吹き込んでも良
い。In the above description, the flux 5 is added by the blowing lance 14. However, the method of adding the flux 5 is not limited to this, and the flux 5 is added to the molten steel 3 in the vacuum chamber 6 from the raw material inlet 12. Alternatively, a blowing tuyere may be provided at the bottom of the ladle 2 and blown from the tuyere.
【００２０】[0020]
【実施例】図１に示すＲＨ真空脱ガス装置を用いて転炉
から出鋼された未脱酸状態の溶鋼を脱炭処理し、次いで
Ｆｅ−Ｓｉ合金を添加して溶鋼を脱酸し、脱酸後、Ｃａ
Ｏ含有量が９０ｗｔ％である生石灰をフラックスとして
溶鋼中に添加する試験を１５ヒート実施した。試験で
は、フラックス中のＣａＯ純分重量（Ｂ）と処理する溶
鋼重量（Ａ）との比（Ｂ／Ａ）を０．０００８〜０．０
１２の範囲で変更し、生石灰添加量の鋳片酸化物含有量
に及ぼす影響について調査した。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a RH vacuum degassing apparatus shown in FIG. 1, a non-deoxidized molten steel discharged from a converter is decarburized, and then an Fe-Si alloy is added to deoxidize the molten steel. After deoxidation, Ca
Fifteen heat tests were performed in which quicklime having an O content of 90 wt% was added as a flux to molten steel. In the test, the ratio (B / A) of the weight of pure CaO (B) in the flux to the weight of molten steel to be treated (A) was 0.0008 to 0.008.
Twelve were changed and the effect of the amount of quicklime added to the slab oxide content was investigated.
【００２１】対象とした溶鋼は、高炉から出銑された溶
銑を溶銑予備処理にて脱硫し、次いで転炉精錬したもの
で、溶鋼の成分は、炭素濃度が０．０３〜０．０４ｗｔ
％、燐濃度が０．１ｗｔ％以下、硫黄濃度が０．００５
ｗｔ％以下で、転炉からの出鋼量は１ヒート２５０トン
である。そして、脱ガス処理後は、連続鋳造機にて厚み
が２２０ｍｍ、幅が９５０ｍｍのスラブ鋳片に鋳造し、
鋳片厚み方向で３箇所の位置から試料を採取して成分を
分析した。鋳片の酸化物の含有量は、総酸素濃度（以
下、「Ｔ．［Ｏ］」と記す）で調査した。表１に、実施
した１５ヒートの鋳片成分分析値、及びＣａＯ純分重量
と溶鋼重量との比（Ｂ／Ａ）を示す。尚、表１に示す分
析値は３箇所の平均値である。The target molten steel is obtained by desulfurizing hot metal spouted from a blast furnace by hot metal pretreatment and then refining the converter. The molten steel has a carbon concentration of 0.03 to 0.04 wt%.
%, Phosphorus concentration is 0.1 wt% or less, sulfur concentration is 0.005%
At wt% or less, the amount of tapping from the converter is 250 tons per heat. And after the degassing process, it is cast into a slab slab having a thickness of 220 mm and a width of 950 mm by a continuous casting machine,
Samples were taken from three positions in the slab thickness direction to analyze the components. The oxide content of the slab was examined by the total oxygen concentration (hereinafter, referred to as “T. [O]”). Table 1 shows the slab component analysis values of the 15 heats performed and the ratio (B / A) of the weight of pure CaO to the weight of molten steel. Note that the analysis values shown in Table 1 are the average values at three locations.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１に示すように、鋳片のＴ．［Ｏ］は、
ヒート間で４５ｐｐｍから１３２ｐｐｍまでばらついて
いるが、これらの結果を、ＣａＯ純分重量と溶鋼重量と
の比（Ｂ／Ａ）との関係で図示したものが図２である。
図２に示すように、ＣａＯ純分重量と溶鋼重量との比
（Ｂ／Ａ）が０．００１から０．０１の範囲では、Ｔ．
［Ｏ］は安定して１００ｐｐｍ以下であった。As shown in Table 1, the T.V. [O]
The results vary from 45 ppm to 132 ppm between heats, and FIG. 2 shows the results in relation to the ratio (B / A) of the weight of pure CaO to the weight of molten steel.
As shown in FIG. 2, when the ratio (B / A) of the weight of pure CaO to the weight of molten steel is in the range of 0.001 to 0.01, T.P.
[O] was 100 ppm or less stably.
【００２４】このように、鋳片のＳｉ濃度に関わらず、
ＣａＯ純分重量と溶鋼重量との比（Ｂ／Ａ）を０．００
１から０．０１とする範囲でフラックスを添加すること
で、鋳片のＴ．［Ｏ］を安定して低減可能であることが
分かった。尚、表１の備考欄に本発明の範囲内のヒート
を実施例とし、又、それ以外のヒートを比較例として区
分して表示した。Thus, regardless of the Si concentration in the slab,
The ratio of the weight of pure CaO to the weight of molten steel (B / A) is 0.00
By adding a flux in the range of 1 to 0.01, the T.V. It was found that [O] could be stably reduced. In the remarks column of Table 1, heats within the scope of the present invention are shown as examples, and other heats are shown as comparative examples.
【００２５】[0025]
【発明の効果】本発明によれば、介在物が少なく、清浄
性に優れた極低炭素Ｓｉキルド鋼を安定して製造するこ
とが可能となり、特に電磁鋼板においては安定して磁気
特性を高めることが達成され、産業上の効果は格別であ
る。According to the present invention, it is possible to stably produce an ultra-low carbon Si-killed steel having a small amount of inclusions and excellent cleanliness. This has been achieved and the industrial effect is exceptional.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本発明を実施したＲＨ真空脱ガス装置の縦断面
概略図である。FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus embodying the present invention.
【図２】鋳片のＴ．［Ｏ］］と［ＣａＯ純分重量（Ｂ）
／溶鋼重量（Ａ）］との関係を示した図である。FIG. [O]] and [CaO pure weight (B)
/ Molten steel weight (A)].
１ ＲＨ真空脱ガス装置 ２ 取鍋 ３ 溶鋼 ４スラグ ５ フラックス ６ 真空槽 ７ 上部槽 ８ 下部槽 ９ 上昇側浸漬管 １０ 下降側浸漬管 １１ Ａｒガス吹き込み管 １２ 原料投入口 １３ ダクト １４ 吹き込みランス １５ ホッパー DESCRIPTION OF SYMBOLS 1 RH vacuum degassing apparatus 2 Ladle 3 Molten steel 4 Slag 5 Flux 6 Vacuum tank 7 Upper tank 8 Lower tank 9 Upside immersion pipe 10 Downside immersion pipe 11 Ar gas blowing pipe 12 Raw material inlet 13 Duct 14 Blowing lance 15 Hopper
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山岡 祐一 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 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichi Yamaoka 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Eiji Sakurai 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Sun Honko Co., Ltd.
Claims (1)
置にて脱炭した後、Ｓｉ脱酸して製造する極低炭素Ｓｉ
キルド鋼の製造方法において、ＲＨ真空脱ガス装置での
処理中に、ＣａＯを主体とするフラックス中のＣａＯ純
分重量（Ｂ）と処理する溶鋼重量（Ａ）との関係が
（１）式を満足するようにして、前記フラックスを溶鋼
中に添加することを特徴とする清浄性に優れた極低炭素
Ｓｉキルド鋼の製造方法。 ０．００１≦Ｂ／Ａ≦０．０１……（１）An ultra-low carbon Si produced by decarburizing molten steel refined in a converter with an RH vacuum degasser and then deoxidizing the Si.
In the method for producing killed steel, the relationship between the pure weight of CaO (B) in the flux mainly composed of CaO and the weight of molten steel (A) to be treated during the treatment in the RH vacuum degassing apparatus is expressed by the following equation (1). A method for producing an ultra-low carbon Si-killed steel having excellent cleanliness, wherein the flux is added to molten steel so as to be satisfactory. 0.001 ≦ B / A ≦ 0.01 (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10094133A JPH11293329A (en) | 1998-04-07 | 1998-04-07 | Production of extra-low carbon silicon-killed steel excellent in cleaning property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10094133A JPH11293329A (en) | 1998-04-07 | 1998-04-07 | Production of extra-low carbon silicon-killed steel excellent in cleaning property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11293329A true JPH11293329A (en) | 1999-10-26 |
Family
ID=14101912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10094133A Pending JPH11293329A (en) | 1998-04-07 | 1998-04-07 | Production of extra-low carbon silicon-killed steel excellent in cleaning property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11293329A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009114491A (en) * | 2007-11-05 | 2009-05-28 | Jfe Steel Corp | Method for refining molten steel by rh-vacuum degassing apparatus |
| CN101786159A (en) * | 2010-03-30 | 2010-07-28 | 武汉钢铁(集团)公司 | Slant-insert type molten iron pretreatment lance and manufacturing method thereof |
| CN109943680A (en) * | 2017-12-21 | 2019-06-28 | 广东韶钢松山股份有限公司 | A kind of Ultra-low carbon, the production method of low silicon, low manganese and low aluminum steel continuous casting billet |
-
1998
- 1998-04-07 JP JP10094133A patent/JPH11293329A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009114491A (en) * | 2007-11-05 | 2009-05-28 | Jfe Steel Corp | Method for refining molten steel by rh-vacuum degassing apparatus |
| CN101786159A (en) * | 2010-03-30 | 2010-07-28 | 武汉钢铁(集团)公司 | Slant-insert type molten iron pretreatment lance and manufacturing method thereof |
| CN109943680A (en) * | 2017-12-21 | 2019-06-28 | 广东韶钢松山股份有限公司 | A kind of Ultra-low carbon, the production method of low silicon, low manganese and low aluminum steel continuous casting billet |
| CN109943680B (en) * | 2017-12-21 | 2020-12-04 | 广东韶钢松山股份有限公司 | Production method of ultra-low carbon, low silicon, low manganese and low aluminum steel continuous casting billet |
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