JPH083622A - Production of low nitrogen steel - Google Patents
Production of low nitrogen steelInfo
- Publication number
- JPH083622A JPH083622A JP6162617A JP16261794A JPH083622A JP H083622 A JPH083622 A JP H083622A JP 6162617 A JP6162617 A JP 6162617A JP 16261794 A JP16261794 A JP 16261794A JP H083622 A JPH083622 A JP H083622A
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- Prior art keywords
- molten steel
- steel
- ladle
- amount
- active component
- Prior art date
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は低窒素鋼の製造方法に
関する。FIELD OF THE INVENTION The present invention relates to a method for producing low nitrogen steel.
【０００２】[0002]
【従来の技術】例えば冷間鍛造性が要求されるステンレ
ス鋼において、Ｎは鋼の靱性，加工性を劣化させること
から、Ｃ，Ｎの量を低くすることが求められる。2. Description of the Related Art For example, in stainless steel which is required to have cold forgeability, N deteriorates the toughness and workability of the steel. Therefore, it is required to reduce the amounts of C and N.
【０００３】そこでステンレス鋼を製造するに際して、
精錬炉内の溶鋼中にＯ2ガスと希釈ガスとしてのＡｒガ
スとを含む混合ガスを大気中で吹き込み、鋼中のＣを反
応させてＣＯガス化し、脱炭するといったことが行われ
ている。Therefore, when manufacturing stainless steel,
A mixed gas containing O 2 gas and Ar gas as a diluent gas is blown into the molten steel in a refining furnace in the atmosphere to react C in the steel into CO gas and decarburize. .
【０００４】その際、溶鋼中のＣの量が減少してくると
吹き込んだＯ2が有効に脱炭に用いられず、Ｃｒと反応
して酸化クロムを生成してしまう問題があることから、
脱炭精錬を行う中で漸次Ｏ2／Ａｒ比率を変化させるよ
うにしている。即ち当初はＯ2の割合を多く、その後次
第にＡｒガスを相対的に多くするようにしている。At that time, when the amount of C in the molten steel decreases, the injected O 2 is not effectively used for decarburization, and there is a problem that it reacts with Cr to form chromium oxide.
The O 2 / Ar ratio is gradually changed during decarburization refining. That is, the ratio of O 2 is increased at the beginning, and the amount of Ar gas is gradually increased thereafter.
【０００５】ところでかかるステンレス鋼を含む低窒素
鋼の製造に当って、精錬後の溶鋼を取鍋に出鋼する際に
相当の落差を以て、例えば６．５ｍ程度の落差を以て溶
鋼を取鍋内に流し込むこととなり、その際大気中の空気
を多量に巻き込んで、空気中のＮを溶鋼中にピックアッ
プしてしまう問題が生じていた。In the production of low-nitrogen steel containing such stainless steel, when the molten steel after refining is tapped into a ladle, there is a considerable drop, for example, about 6.5 m in the ladle. When it is poured, a large amount of air in the atmosphere is entrained at that time, and there is a problem that N in the air is picked up in the molten steel.
【０００６】そのＮのピックアップ量は２０〜６０ｐｐ
ｍ程度に及び、従ってＮの規格値が１５０ｐｐｍ以下で
あるとすると、取鍋への出鋼直前の精錬末期においてＮ
の量を９０ｐｐｍ以下に抑えておかなければならないこ
とになる。The pickup amount of N is 20 to 60 pp
Therefore, assuming that the standard value of N is 150 ppm or less, N at the final stage of refining just before tapping the ladle.
Therefore, the amount must be kept below 90 ppm.
【０００７】従来の製造方法にあっては、上記取鍋への
出鋼に際してのＮのピックアップによって、最終的な鋼
のＮ量を一定以下に少なく抑えることが難しい問題があ
った。また特にステンレスの脱炭精錬において、上記希
釈ガスとして高価なＡｒガスを多く用いざるを得ず、Ａ
ｒガスの使用量が多くなるといった問題も内包してい
た。In the conventional manufacturing method, there is a problem that it is difficult to keep the final N amount of steel to a certain level or less by picking up N when tapping the steel in the ladle. In particular, in decarburizing and refining stainless steel, it is unavoidable to use a large amount of expensive Ar gas as the above-mentioned dilution gas.
There was also a problem that the amount of r gas used increased.
【０００８】上述したようにステンレス鋼の脱炭精錬に
おいては、鋼中のＣ量の低下に応じて漸次Ｏ2ガスの量
を減じ、相対的にＡｒガス等の希釈ガスの量を多くして
いく。Ｎ2ガスはその際の希釈ガスとしても使用可能な
ものであるが、精錬工程においてＮの含有量を低く抑え
なければならない場合、希釈ガスとしてＮ2ガスを用い
ると鋼中のＮ量が増してしまうため、やむなく高価なＡ
ｒガスを多く使用せざるを得なくなるのである。その結
果、希釈ガスに要する費用も高いものとなる。As described above, in the decarburization refining of stainless steel, the amount of O 2 gas is gradually reduced in accordance with the decrease in the amount of C in the steel, and the amount of diluent gas such as Ar gas is relatively increased. Go. N 2 gas can also be used as a diluent gas at that time, but if the N content should be kept low in the refining process, the use of N 2 gas as a diluent gas increases the N content in the steel. Therefore, it is unavoidably expensive A
This means that a large amount of r gas must be used. As a result, the cost required for the diluent gas is also high.
【０００９】[0009]
【課題を解決するための手段】本願の発明はこのような
課題を解決するためになされたものである。而して本願
の発明は、精錬炉で精錬した溶鋼を取鍋に出鋼後鋳込み
を行う低窒素鋼の製造方法において、前記取鍋への出鋼
直前において前記精錬炉内の溶鋼に表面活性成分を添加
して該表面活性成分を該溶鋼表面に吸着させ、しかる後
に該溶鋼を前記取鍋に出鋼することを特徴とする（請求
項１）。The invention of the present application has been made to solve such a problem. Thus, the invention of the present application is a method for producing low-nitrogen steel in which molten steel refined in a refining furnace is cast into a ladle after being tapped, and surface activation is performed on molten steel in the refining furnace immediately before tapping to the ladle. A component is added so that the surface active component is adsorbed on the surface of the molten steel, and then the molten steel is tapped into the ladle (claim 1).
【００１０】本願の別の発明は、請求項１の製造方法に
おいて、前記表面活性成分としての酸素を前記溶鋼中に
加えて酸素を該溶鋼の表面に吸着させた上で該溶鋼を前
記精錬炉より取鍋に出鋼し、しかる後該取鍋において脱
酸剤を添加して該溶鋼中のＯ量を所定レベルまで低減す
ることを特徴とする（請求項２）。According to another invention of the present application, in the manufacturing method of claim 1, oxygen as the surface-active component is added to the molten steel to adsorb oxygen on the surface of the molten steel, and then the molten steel is refined in the refining furnace. Further, the steel is tapped into a ladle, and then a deoxidizer is added to the ladle to reduce the amount of O in the molten steel to a predetermined level (claim 2).
【００１１】本願の更に別の発明は、請求項１又は２の
製造方法において、前記溶鋼中の酸素濃度を２００ｐｐ
ｍ以上とすることを特徴とする（請求項３）。Yet another invention of the present application is the method according to claim 1 or 2, wherein the oxygen concentration in the molten steel is 200 pp.
It is characterized by making it m or more (claim 3).
【００１２】本願の更に別の発明は、請求項１，２又は
３の製造方法において、前記低窒素鋼が、最終Ｎ量１５
０ｐｐｍ以下のステンレス鋼であることを特徴とする
（請求項４）。Still another invention of the present application is the manufacturing method according to claim 1, 2 or 3, wherein the low nitrogen steel has a final N content of 15
It is characterized in that it is 0 ppm or less of stainless steel (claim 4).
【００１３】[0013]
【作用及び発明の効果】上記のように本発明は、精錬さ
れた溶鋼を取鍋に出鋼する直前において溶鋼中に表面活
性成分を添加するものである。従来、溶鋼中にＮがピッ
クアップされる過程でまずＮ2ガスが溶鋼表面に吸着さ
れ、次いで吸着されたＮ2が溶鋼内に入り込んでいくも
のと考えられている。そこで本発明では溶鋼を出鋼する
直前に精錬炉内において表面活性成分を添加するように
した。この表面活性成分として酸素を好適に用いること
ができる。As described above, according to the present invention, a surface active component is added to molten steel immediately before tapping the refined molten steel into a ladle. Conventionally, it is considered that N 2 gas is first adsorbed on the surface of the molten steel in the process of picking up N in the molten steel, and then the adsorbed N 2 enters into the molten steel. Therefore, in the present invention, the surface active component is added in the refining furnace immediately before tapping molten steel. Oxygen can be preferably used as the surface active component.
【００１４】而して鋼中に添加された酸素等表面活性成
分は溶鋼の表面に吸着され、Ｎ2ガスが溶鋼表面に吸着
されるのを抑制するように働く。因みにこのことは鋼中
の［Ｏ］量と溶鋼表面へのＯ2の吸着量、又は吸窒速度
との関係についての報告例から理解することができる。Thus, surface active components such as oxygen added to the steel are adsorbed on the surface of the molten steel and work to suppress the adsorption of N 2 gas on the surface of the molten steel. Incidentally, this can be understood from a reported example of the relationship between the [O] amount in the steel and the amount of O 2 adsorbed on the surface of the molten steel, or the nitrification rate.
【００１５】図２はその［Ｏ］量と鋼表面へのＯ2の吸
着量との関係を示したものであり、また図３は［Ｏ］量
と吸窒速度との関係を表したものである。これらの図か
ら、鋼中の［Ｏ］量を多くすることによって吸窒量が減
少することが理解できる。FIG. 2 shows the relation between the [O] amount and the adsorption amount of O 2 on the steel surface, and FIG. 3 shows the relation between the [O] amount and the nitrogen absorption rate. Is. From these figures, it can be understood that the amount of nitrogen absorption is decreased by increasing the amount of [O] in the steel.
【００１６】本発明はこれを利用し、溶鋼への酸素等の
表面活性成分の添加を精錬末期において行うことで、取
鍋への溶鋼の流し込み時に空気の巻込みに起因するＮの
ピックアップを抑制するもので、本発明によれば精錬炉
から取鍋への溶鋼の出鋼の際にＮのピックアップを、例
えば２０ｐｐｍ以下の少量に抑制できることが確認され
ている。従って本発明によれば、低窒素鋼において最終
的に鋼中に含まれるＮ量を従来より少なくすることがで
きる。The present invention utilizes this, and by adding surface active components such as oxygen to the molten steel at the final stage of refining, it suppresses the pickup of N due to the entrainment of air when the molten steel is poured into the ladle. Therefore, according to the present invention, it has been confirmed that the pickup of N when the molten steel is tapped from the refining furnace to the ladle can be suppressed to a small amount of, for example, 20 ppm or less. Therefore, according to the present invention, in the low nitrogen steel, the N content finally contained in the steel can be made smaller than the conventional amount.
【００１７】尚、表面活性成分として酸素ガスを吹き込
んだ場合において、鋼中に富化した酸素を低減するため
の手段が問題となる。本発明者は各種実験，研究を行う
中で、取鍋中にＦｅ−Ｓｉ等の脱酸剤を添加すること
で、鋼中に富化した酸素を所望レベルまで良好に低下さ
せることができた。When oxygen gas is blown in as a surface active component, a means for reducing the oxygen enriched in the steel becomes a problem. The present inventor was able to satisfactorily reduce oxygen enriched in steel to a desired level by adding a deoxidizing agent such as Fe-Si to a ladle during various experiments and studies. .
【００１８】上記酸素ガスの吹込量としては鋼中の
［Ｏ］濃度が２００ｐｐｍ以上となる量で行うのが良
く、これによってＮのピックアップを良好に防止するこ
とができる。尚他の方法で鋼中の［Ｏ］濃度を２００ｐ
ｐｍ以上とすることも可能である。The oxygen gas is preferably blown in such an amount that the [O] concentration in the steel is 200 ppm or more, whereby N pickup can be effectively prevented. The [O] concentration in the steel is 200 p
It is also possible to set it to pm or more.
【００１９】このことは図２及び３に示す［Ｏ］と吸着
量，吸窒速度との関係を表す曲線において、［Ｏ］２０
０ｐｐｍを境として曲線の傾きが何れも急激に「寝た」
状態となることからも理解できる。This is because [O] 20 in the curves showing the relationship between [O] shown in FIGS.
The slope of each curve suddenly "sleeped" at 0 ppm
It can be understood from the state.
【００２０】本発明は、特にＮ量が１５０ｐｐｍ以下に
規制される低窒素ステンレス鋼の製造に適用して特に効
果の大きいものである。The present invention is particularly effective when applied to the production of low-nitrogen stainless steel whose N content is regulated to 150 ppm or less.
【００２１】[0021]
【実施例】次に本発明の実施例を詳述する。表１に示す
組成のステンレス鋼を溶解し、次いで精錬炉においてま
ず大気中での脱炭精錬を行った。このとき溶鋼中に酸素
ガスと非酸化性の希釈ガスとから成る混合ガスを吹き込
み、鋼中のＣと吹き込んだＯとの反応によって脱炭を行
わせるとともに、鋼中のＣ量の減少につれて段階的にＯ
2ガスと希釈ガスとの比率を変化させた（漸次希釈ガス
の量を多くした）。EXAMPLES Next, examples of the present invention will be described in detail. The stainless steel having the composition shown in Table 1 was melted, and then decarburization refining was first performed in the atmosphere in a refining furnace. At this time, a mixed gas consisting of oxygen gas and a non-oxidizing diluent gas is blown into the molten steel to cause decarburization by the reaction between C in the steel and the blown O, and at the same time as the amount of C in the steel decreases, O
The ratio of the 2 gas and the diluent gas was changed (the amount of the diluent gas was gradually increased).
【００２２】[0022]
【表１】 [Table 1]
【００２３】次いで鋼中のＣ量が一定レベル（０．１５
％）まで低下した段階で炉内を減圧状態とする減圧精錬
処理を行った。即ち炉内を４０〜５０Ｔｏｒｒ（一般に
は２０〜２００Ｔｏｒｒの範囲がよい）に減圧するとと
もに、溶鋼中に希釈ガスのみを吹き込んで主にスラグ中
のＣｒ2Ｏ3と鋼中のＣとの反応に基づいて脱炭精錬を行
い、また併せてＦｅ−Ｓｉの添加によって酸化クロムの
還元を行った。これら大気処理及び減圧処理を含む精錬
を終えた段階で、鋼中の酸素は５０ｐｐｍであった。Next, the amount of C in the steel is kept at a constant level (0.15
%), A reduced pressure refining process was performed in which the pressure inside the furnace was reduced. That is, while depressurizing the furnace to 40 to 50 Torr (generally, a range of 20 to 200 Torr is good), only diluting gas is blown into molten steel to mainly react with Cr 2 O 3 in slag and C in steel. Based on this, decarburization refining was performed, and in addition, chromium oxide was reduced by adding Fe—Si. Oxygen in the steel was 50 ppm when the refining including the atmospheric treatment and the pressure reduction treatment was completed.
【００２４】次に精錬後、溶鋼の取鍋への出鋼直前にお
いてＯ2ガスの吹込みを行った。このときのＯ2ガスの吹
込みは１００Ｎｍ3と２００Ｎｍ3との２通りで行った。
この結果、溶鋼中の［Ｏ］は前者の場合には約２００ｐ
ｐｍ、後者の場合には約５００ｐｐｍとなった。次いで
溶鋼を取鍋に移し、Ｆｅ−Ｓｉを添加して脱酸処理を行
った。Next, after refining, O 2 gas was blown into the ladle of molten steel immediately before tapping. Blowing of O 2 gas at this time was carried out in duplicate with 100 Nm 3 and 200 Nm 3.
As a result, [O] in molten steel is about 200p in the former case.
pm, in the latter case it was about 500 ppm. Next, the molten steel was transferred to a ladle, and Fe-Si was added for deoxidation treatment.
【００２５】これらの処理において、溶鋼の精錬炉から
取鍋への流し込み前後におけるＮ量を調べ、Ｎのピック
アップ量を求めたところ、図１に示しているようにＯ2
の吹込みを行わない通常の方法にあってはＮのピックア
ップ量が２０〜６０ｐｐｍであるのに対し、Ｏ2の吹込
みを行った場合Ｎのピックアップが２０ｐｐｍ以下に抑
えられることを確認した。[0025] In these processes, examine the N content before and after pouring from the smelting furnace of molten steel into the ladle, was determined pickup amount of N, O 2 as shown in FIG. 1
It was confirmed that the amount of N pickup was 20 to 60 ppm in the usual method in which N was not blown, whereas the amount of N pickup was suppressed to 20 ppm or less when O 2 was blown.
【００２６】尚、Ｏ2の吹込みを１００Ｎｍ3の量で行っ
た場合において、取鍋に脱酸剤を投入して脱酸処理を行
ったところ、溶鋼中の［Ｏ］を約５０ｐｐｍまで低下さ
せることができた。When O 2 was blown in at an amount of 100 Nm 3 , deoxidizing treatment was carried out by adding a deoxidizing agent to the ladle, and [O] in the molten steel was reduced to about 50 ppm. I was able to do it.
【００２７】以上本発明の実施例を詳述したがこれはあ
くまで一例示である。例えば上例では表面活性成分とし
てＯ2ガスを吹き込むようにしているが、Ｓの含有量を
多く（例えば０．２０％程度）できる鋼種については、
Ｏ2の全部又は一部をＳにて置換するといったことも可
能である。その他本発明はその主旨を逸脱しない範囲に
おいて、種々変更を加えた態様で実施可能である。Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the above example, O 2 gas is blown as the surface active component, but for steel types that can increase the S content (for example, about 0.20%),
It is also possible to replace all or part of O 2 with S. Others The present invention can be implemented in variously modified modes without departing from the spirit of the invention.
【図１】本発明の実施例において得られたＮのピックア
ップの低減効果を従来のそれと比較して示す図である。FIG. 1 is a diagram showing a reduction effect of N pickup obtained in an example of the present invention in comparison with a conventional effect.
【図２】溶鋼中の［Ｏ］量と表面へのＯ2の吸着量との
関係を示す図である。FIG. 2 is a diagram showing the relationship between the amount of [O] in molten steel and the amount of O 2 adsorbed on the surface.
【図３】溶鋼中の［Ｏ］量と吸窒速度との関係を表す図
である。FIG. 3 is a diagram showing the relationship between the amount of [O] in molten steel and the rate of nitrogen absorption.
Claims (4)
込みを行う低窒素鋼の製造方法において前記取鍋への出
鋼直前において前記精錬炉内の溶鋼に表面活性成分を添
加して該表面活性成分を該溶鋼表面に吸着させ、しかる
後に該溶鋼を前記取鍋に出鋼することを特徴とする低窒
素鋼の製造方法。1. A method for producing low-nitrogen steel in which molten steel smelted in a smelting furnace is cast into a ladle after being tapped, and a surface active component is added to the molten steel in the smelting furnace immediately before tapping in the ladle. A method for producing low nitrogen steel, characterized in that the surface active component is adsorbed on the surface of the molten steel, and then the molten steel is tapped into the ladle.
活性成分としての酸素を前記溶鋼中に加えて酸素を該溶
鋼の表面に吸着させた上で該溶鋼を前記精錬炉より取鍋
に出鋼し、しかる後該取鍋において脱酸剤を添加して該
溶鋼中のＯ量を所定レベルまで低減することを特徴とす
る低窒素鋼の製造方法。2. The manufacturing method according to claim 1, wherein oxygen as the surface-active component is added to the molten steel to adsorb oxygen on the surface of the molten steel, and then the molten steel is discharged from the refining furnace to a ladle. A method for producing a low-nitrogen steel, which comprises steel-making, and then adding a deoxidizing agent in the ladle to reduce the amount of O in the molten steel to a predetermined level.
記溶鋼中の酸素濃度を２００ｐｐｍ以上とすることを特
徴とする低窒素鋼の製造方法。3. The method for producing low nitrogen steel according to claim 1, wherein the oxygen concentration in the molten steel is 200 ppm or more.
て、前記低窒素鋼が、最終Ｎ量１５０ｐｐｍ以下のステ
ンレス鋼であることを特徴とする低窒素鋼の製造方法。4. The method for producing low nitrogen steel according to claim 1, 2 or 3, wherein the low nitrogen steel is stainless steel having a final N content of 150 ppm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6162617A JPH083622A (en) | 1994-06-20 | 1994-06-20 | Production of low nitrogen steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6162617A JPH083622A (en) | 1994-06-20 | 1994-06-20 | Production of low nitrogen steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH083622A true JPH083622A (en) | 1996-01-09 |
Family
ID=15758015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6162617A Pending JPH083622A (en) | 1994-06-20 | 1994-06-20 | Production of low nitrogen steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH083622A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012207272A (en) * | 2011-03-30 | 2012-10-25 | Nisshin Steel Co Ltd | Method for preventing nitrogen absorption when smelting stainless steel |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5760012A (en) * | 1980-09-26 | 1982-04-10 | Sumitomo Metal Ind Ltd | Production of extremely low nitrogen stainless steel |
-
1994
- 1994-06-20 JP JP6162617A patent/JPH083622A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5760012A (en) * | 1980-09-26 | 1982-04-10 | Sumitomo Metal Ind Ltd | Production of extremely low nitrogen stainless steel |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012207272A (en) * | 2011-03-30 | 2012-10-25 | Nisshin Steel Co Ltd | Method for preventing nitrogen absorption when smelting stainless steel |
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