JPH0617113A - Vacuum degassing method for molten steel - Google Patents
Vacuum degassing method for molten steelInfo
- Publication number
- JPH0617113A JPH0617113A JP17351992A JP17351992A JPH0617113A JP H0617113 A JPH0617113 A JP H0617113A JP 17351992 A JP17351992 A JP 17351992A JP 17351992 A JP17351992 A JP 17351992A JP H0617113 A JPH0617113 A JP H0617113A
- Authority
- JP
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- Prior art keywords
- molten steel
- gas
- degassing
- ladle
- content
- 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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- Treatment Of Steel In Its Molten State (AREA)
Abstract
(57)【要約】
【目的】 還流式脱ガス処理により的中率よく溶鋼中に
溶存する窒素含有量を調整する。
【構成】 還流ガス吹き込み管８から上昇浸漬管６に吹
き込む還流ガスとしてArとＮ2 とを混合したガスを用
い、この混合ガス中のＮ2 ガス混合割合を、取鍋３内に
おける溶鋼４の脱ガス処理前の測定〔Ｎ〕含有量と脱ガ
ス終了後の目標〔Ｎ〕含有量との差に基づいて決定し、
この決定したＮ2 ガス混合割合を有するArとの混合ガス
を上昇浸漬管６に吹き込んで脱ガス処理終了時の溶鋼の
〔Ｎ〕を的中率よく加窒する。
(57) [Summary] [Purpose] To adjust the nitrogen content dissolved in molten steel with good precision by refluxing degassing. [Composition] A mixed gas of Ar and N 2 is used as a reflux gas blown from the reflux gas blow-in pipe 8 to the ascending dip pipe 6, and the N 2 gas mixing ratio in this mixed gas is calculated as follows. Determined based on the difference between the measured [N] content before degassing and the target [N] content after degassing,
The mixed gas with Ar having the determined N 2 gas mixing ratio is blown into the ascending dip tube 6 to nitrify the molten steel [N] at the end of the degassing with good accuracy.
Description
【０００１】[0001]
【産業上の利用分野】本発明は、還流式真空脱ガス装置
を用いて溶鋼の窒素Ｎ含有量を調整する溶鋼の真空脱ガ
ス処理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 vacuum degassing treatment method for molten steel in which the nitrogen N content of the molten steel is adjusted by using a reflux type vacuum degassing apparatus.
【０００２】[0002]
【従来の技術】一般に転炉により吹錬した溶鋼には窒
素、酸素および水素等のガス成分が含まれており、溶鋼
中にガス成分が多量に溶存すると鋼の性質に悪影響を及
ぼすことになる。このため転炉から出鋼した取鍋内の溶
鋼を減圧下の脱ガス槽内にて脱ガス処理している。たと
えば還流式真空脱ガス装置では、脱ガス槽の下部に配設
された上昇浸漬管と下降浸漬管とを取鍋内の溶鋼中に浸
漬し、減圧された脱ガス槽内に取鍋から溶鋼を吸い上
げ、上昇浸漬管に還流ガスを吹き込むことにより溶鋼を
上昇させ、下降浸漬管を介して脱ガス槽内の溶鋼を取鍋
に戻すことによって溶鋼を取鍋と脱ガス槽との間に循環
させる。この場合、脱ガス槽内のガスを排気することに
より槽内を数トールに減圧してあるので、溶鋼中に溶存
する窒素Ｎ、酸素Ｏ、水素Ｈが低減される。2. Description of the Related Art Generally, molten steel blown by a converter contains gas components such as nitrogen, oxygen and hydrogen, and if a large amount of gas components are dissolved in the molten steel, the properties of the steel will be adversely affected. . For this reason, the molten steel in the ladle tapped from the converter is degassed in a degassing tank under reduced pressure. For example, in a reflux-type vacuum degassing device, the ascending dip pipe and the descending dip pipe placed at the bottom of the degassing tank are immersed in the molten steel in the ladle, and the molten steel from the ladle is placed in the degassing tank under reduced pressure. The molten steel is sucked up and the reflux steel is blown into the ascending dip tube to raise the molten steel, and the molten steel in the degassing tank is returned to the ladle through the descending dip tube to circulate the molten steel between the ladle and the degassing tank. Let In this case, the gas in the degassing tank is exhausted to reduce the pressure in the tank to several torr, so that nitrogen N 2 , oxygen O 2 , and hydrogen H 2 dissolved in the molten steel are reduced.
【０００３】ところで窒素は、鋼の靱性に悪影響を及ぼ
すことから、従来から窒素を低減することがなされてい
たが、鋼種によっては必ずしも有害であるとは限らず、
たとえば特殊鋼分野では、鋼を強化するための元素とし
て窒素が注目されており、鋼強度を高めるということ、
窒素が安価で豊富に存在するなどの理由から溶鋼のＮ含
有量を調整することが試みられている。By the way, since nitrogen has a negative effect on the toughness of steel, it has been conventionally reduced, but it is not always harmful depending on the type of steel.
For example, in the field of special steels, nitrogen is attracting attention as an element for strengthening steels, which means to increase steel strength.
Attempts have been made to adjust the N content of molten steel for reasons such as nitrogen being inexpensive and abundant.
【０００４】また鋼中の窒素は、オーステナイト形成元
素であるので鋼の強度を高めるために添加されており、
非金属介在物を少なくし、かつ微細結晶化する効果を持
つことから疲労強度が高い機械構造用の高窒素鋼を溶製
するために還流式真空脱ガス装置を用いて、溶鋼中の溶
存窒素を富化し、鋼の窒素含有量を積極的に高めること
が行われている。Since nitrogen in steel is an austenite forming element, it is added to enhance the strength of steel.
Using a reflux type vacuum degasser to melt high nitrogen steel for machine structures, which has high fatigue strength because it has the effect of reducing non-metallic inclusions and fine crystallization, the dissolved nitrogen in the molten steel is used. To increase the nitrogen content of steel.
【０００５】従来、還流式真空脱ガス装置を用いて溶鋼
の窒素含有量Ｎを調整する場合には、上昇浸漬管に吹き
込む還流ガスの種類を脱ガス処理過程の途中で、Ｎ2 か
らArガスに切り換えることにより、吸窒と脱窒を制御し
て溶鋼中のＮを調整していた。この場合、鋼中の目標Ｎ
値に対してＮ2 ガス吹き込み時間のみが決定され、残り
のAr吹き込みによる脱ガス処理中は、溶鋼温度が所定温
度になるまでArガスの吹き込みを行っていた。Conventionally, when adjusting the nitrogen content N of molten steel using a reflux type vacuum degassing apparatus, the type of the reflux gas blown into the ascending dip tube is changed from N 2 to Ar gas during the degassing process. By switching to, the N in the molten steel was adjusted by controlling the absorption and denitrification. In this case, the target N in steel
Only the N 2 gas blowing time was determined for the value, and during the remaining degassing treatment by Ar blowing, Ar gas was blown until the molten steel temperature reached a predetermined temperature.
【０００６】[0006]
【発明が解決しようとする場合】前記従来の方法では、
図３に示すように溶鋼の窒素を富化するＮ2 ガス吹き込
みによる処理時間（Ｎ2 処理）のみが決められ、脱窒さ
れる後半のArガス吹き込みによる処理時間（Ar処理）
は、溶鋼の温度が所定の温度になるように決定されるの
で、最初に予定していた処理時間と異なる処理時間とな
り、たとえば処理時間が予定よりオーバすると目標Ｎ値
範囲より低い値になってしまう。このようにAr処理時間
がばらつくと鋼中Ｎ値のばらつきも大きくなり、目標Ｎ
値範囲に的中しなくなるという問題があった。DISCLOSURE OF THE INVENTION In the above conventional method,
As shown in FIG. 3, only the treatment time (N 2 treatment) by blowing N 2 gas for enriching the molten steel with nitrogen is determined, and the treatment time by Ar gas blowing in the latter half of denitrification (Ar treatment)
Is determined so that the temperature of the molten steel reaches a predetermined temperature, so the processing time differs from the initially planned processing time. For example, if the processing time exceeds the scheduled time, the value will be lower than the target N value range. I will end up. In this way, if the Ar treatment time varies, the variation in N value in steel also increases, and the target N
There was a problem that the value range was not correct.
【０００７】本発明は、このような従来技術の問題点に
かんがみて、上昇浸漬管に吹き込む還流ガスとしてArと
Ｎ2 との混合ガスを用いることによって溶鋼のＮをばら
つき少なく調整することができる溶鋼の真空脱ガス処理
方法を提供するものである。In view of such problems of the prior art, the present invention can adjust N of molten steel with little variation by using a mixed gas of Ar and N 2 as a reflux gas blown into an ascending dip tube. A vacuum degassing treatment method for molten steel is provided.
【０００８】[0008]
【課題を解決するための手段】前記目的を達成するため
の本発明は、脱ガス槽の下部に配設された上昇浸漬管と
下降浸漬管とを取鍋内の溶鋼中に浸漬し、減圧された脱
ガス槽内に取鍋から溶鋼を吸い上げ、上昇浸漬管に還流
ガスを吹き込むことにより取鍋と脱ガス槽との間に溶鋼
を循環させるようにした溶鋼の真空脱ガス処理方法にお
いて、前記上昇浸漬管に吹き込む還流ガスとしてArとＮ
2 とを混合したガスを用い、該混合ガスのＮ2 ガス混合
割合を、取鍋内における溶鋼の脱ガス処理前の測定Ｎ含
有量と脱ガス処理終了後の目標Ｎ含有量との差に基づい
て決定し、この決定したＮ2 ガス混合割合を有するArと
の混合ガスを上昇浸漬管に吹き込むことによって脱ガス
処理終了後の溶鋼のＮ含有量を目標Ｎ含有量範囲に的中
させることを特徴とする溶鋼の真空脱ガス処理方法であ
る。Means for Solving the Problems The present invention for attaining the above-mentioned object is to immerse an ascending dip pipe and a descending dip pipe disposed in a lower portion of a degassing tank in molten steel in a ladle to reduce pressure. In the method for vacuum degassing treatment of molten steel, the molten steel is sucked up from the ladle into the degassing tank, and the molten steel is circulated between the ladle and the degassing tank by blowing the reflux gas into the ascending dip tube. Ar and N as the reflux gas blown into the ascending dip tube
With 2 and a mixed gas, the N 2 gas mixing ratio of the mixed gas, the difference between the target N content after the measuring the N content and degassed before the end degassing treatment of the molten steel in the ladle Based on the above, the mixed gas with Ar having the determined N 2 gas mixing ratio is blown into the ascending dip tube to bring the N content of the molten steel after the degassing treatment into the target N content range. Is a vacuum degassing treatment method for molten steel.
【０００９】[0009]
【作用】本発明では、取鍋内における溶鋼の脱ガス処理
前に測定したＮ含有量と脱ガス処理終了後の目標Ｎ含有
量に基づき溶鋼中のＮ含有量の増減分を求めて、そのＮ
値増減分に合うように、ArとＮ2 とを混合したガス中の
Ｎ2 混合割合を０〜 100％の範囲に決定する。還流式真
空脱ガス装置により溶鋼の脱ガス処理中は、混合ガス中
のＮ2 混合割合を一定に保って上昇浸漬管中に吹き込む
ため、脱ガス処理時間がばらついても鋼中のＮのばらつ
きを従来より小さくすることができる。In the present invention, based on the N content measured before the degassing treatment of the molten steel in the ladle and the target N content after the degassing treatment, the increase / decrease of the N content in the molten steel is calculated, N
The N 2 mixing ratio in the gas in which Ar and N 2 are mixed is determined to be in the range of 0 to 100% so as to match the value increase / decrease. During the degassing process of molten steel by the reflux type vacuum degassing device, the N 2 mixing ratio in the mixed gas is kept constant and blown into the ascending dip tube, so that the N in the steel varies even if the degassing process time varies. Can be made smaller than before.
【００１０】Arとの混合ガス中のＮ2 混合割合は、たと
えば取鍋内の溶鋼を脱ガス処理中に窒素を添加して加窒
する場合には、図２に示すように予め脱ガス処理終了後
の取鍋目標Ｎと脱ガス処理前に分析で測定した脱ガス処
理前Ｎとの差ΔＮとArとの混合ガス中のＮ2 ガス混合割
合との関係をグラフ表示しておき、これに基づいて決定
することができる。このＮ2 ガス混合割合を決定する手
法としては図２に示すようなグラフを予め作成しておく
ものに限定するものではなく、表で示してもよく、また
予め定めた算出式を用いて計算により決定することもで
きる。真空脱ガス処理時間のバラツキ、処理前Ｎレベル
により加窒の効率が変動する、などにより混合比に幅を
持たせて管理する方が好ましく、目標値を中央とするＮ
含有量の上限値と下限値との範囲で管理するのが実際的
である。The N 2 mixing ratio in the mixed gas with Ar is, for example, when the molten steel in the ladle is denitrified by adding nitrogen during the degassing process, as shown in FIG. The relationship between the difference ΔN between the ladle target N after the end and the N before degassing treatment measured by the analysis before degassing treatment and the N 2 gas mixing ratio in the mixed gas of Ar is displayed in a graph. Can be determined based on. The method of determining the N 2 gas mixture ratio is not limited to the one in which the graph shown in FIG. 2 is created in advance, but may be shown in a table, or calculated using a predetermined calculation formula. Can also be determined by. Vacuum degassing treatment time variations, the efficiency of the pressurized nitrogen by pretreatment N level varies, it is preferable who manages to have a width in the mixing ratio due to, N to the target value and the center
It is practical to manage the content within the range of the upper limit value and the lower limit value.
【００１１】[0011]
【実施例】以下、本発明の実施例を図面に基づいて説明
する。図１は還流式真空脱ガス装置１の概略縦断面であ
り、図１に示すように脱ガス槽２は竪型の円筒容器であ
り、その内部に耐火物が内張りされている。一般に脱ガ
ス槽２は動かないように建屋内に固定されており、その
直下に取鍋３が搬入されリフトテーブル（図示せず）に
載置されると脱ガス槽２に向かって上昇し、脱ガス槽２
の下部に配設された上昇浸漬管６と下降浸漬管７とが取
鍋３内の溶鋼４中に浸漬される。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic vertical cross-section of a reflux type vacuum degassing apparatus 1. As shown in FIG. 1, the degassing tank 2 is a vertical cylindrical container in which a refractory material is lined. Generally, the degassing tank 2 is fixed in the building so that it does not move, and when the ladle 3 is carried directly under it and placed on a lift table (not shown), it rises toward the degassing tank 2. Degas tank 2
The ascending dip pipe 6 and the descending dip pipe 7 arranged in the lower part of the are immersed in the molten steel 4 in the ladle 3.
【００１２】脱ガス槽２の上部には排気ダクト５を介し
て排気ブロワ（図示せず）に連通され、槽内のガスを外
部に排出して減圧すると、取鍋３内の溶鋼４が脱ガス槽
２内に吸い上げられる。上昇浸漬管６は還流ガス吹き込
み管８を具え、溶鋼を上昇させる働きを持っている。す
なわち還流ガス吹き込み管８の上流側は流量調節弁（図
示せず）を経由して窒素ガス（Ｎ2 ガス）供給源および
アルゴンガス（Arガス）供給源に連通されＮ2 およびAr
の混合ガスが、還流ガス吹き込み管８を介して上昇浸漬
管６の溶鋼流通路に吹き込まれると溶鋼の見掛けの比重
が低下して溶鋼が上昇する。An upper part of the degassing tank 2 is connected to an exhaust blower (not shown) through an exhaust duct 5, and when the gas in the tank is discharged to the outside and the pressure is reduced, the molten steel 4 in the ladle 3 is removed. It is sucked up into the gas tank 2. The ascending dip pipe 6 has a reflux gas blowing pipe 8 and has a function of raising the molten steel. That is, the upstream side of the reflux gas blowing pipe 8 is connected to a nitrogen gas (N 2 gas) supply source and an argon gas (Ar gas) supply source via a flow rate control valve (not shown) and is connected to N 2 and Ar.
When the mixed gas is blown into the molten steel flow passage of the ascending dip pipe 6 via the reflux gas blowing pipe 8, the apparent specific gravity of the molten steel decreases and the molten steel rises.
【００１３】次に取鍋３内の溶鋼４を脱ガス処理しつ
つ、溶鋼４の窒含有量Ｎを調整する場合について説明す
る。転炉の吹錬が終了すると、溶鋼を取鍋３に出鋼す
る。この溶鋼を収容した取鍋３を脱ガス槽２の直下に搬
入し、これをリフトテーブルにより上昇させ上昇浸漬管
６と下降浸漬管７とを溶鋼４に浸漬させる。この時、脱
ガス処理前における取鍋３内の溶鋼４のＮを分析により
測定する。Next, the case where the nitrogen content N of the molten steel 4 is adjusted while degassing the molten steel 4 in the ladle 3 will be described. When the blowing of the converter is completed, the molten steel is tapped in the ladle 3. The ladle 3 accommodating the molten steel is carried into the degassing tank 2 and is raised by a lift table to immerse the ascending dipping pipe 6 and the descending dipping pipe 7 in the molten steel 4. At this time, N of the molten steel 4 in the ladle 3 before the degassing process is measured by analysis.
【００１４】排気ダクト５を介して槽内を排気して減圧
し、取鍋３内の溶鋼４が脱ガス槽２内に吸い上げられる
ので、引き続き窒素ガス供給源およびアルゴンガス源の
各流量調節弁の開度を調節してＮ2 ガス流量とアルゴン
ガス流量を制御してArとの混合ガス中のＮ2 ガス混合割
合を所定の割合にして還流ガス吹き込み管８に供給す
る。この場合の混合ガス供給流量を約 1000l／分とす
る。かくして還流ガス吹き込み管８を介して上昇浸漬管
６の溶鋼流通路に混合ガスを吹き込むと、溶鋼の見掛け
の比重が減少して溶鋼４が上昇し、脱ガス槽２内の湯面
が盛り上がる。Since the inside of the tank is exhausted through the exhaust duct 5 to reduce the pressure and the molten steel 4 in the ladle 3 is sucked up into the degassing tank 2, the flow rate control valves of the nitrogen gas supply source and the argon gas source continue. Is controlled to control the N 2 gas flow rate and the argon gas flow rate, and the N 2 gas mixing ratio in the mixed gas with Ar is supplied to the reflux gas blowing pipe 8 at a predetermined ratio. In this case, the mixed gas supply flow rate shall be about 1000 l / min. Thus, when the mixed gas is blown into the molten steel flow passage of the ascending dip pipe 6 through the reflux gas blowing pipe 8, the apparent specific gravity of the molten steel decreases, the molten steel 4 rises, and the molten metal surface in the degassing tank 2 rises.
【００１５】溶鋼４と共に上昇する混合ガスに含まれる
Ｎ2 ガスが溶鋼４中に溶け込み、窒素含有量Ｎが上昇す
る。溶鋼４と共に上昇した混合ガスが溶鋼４から分離す
るときに湯面が激しく泡立ち、スプラッシュが発生す
る。このようにして脱ガス槽２内に上昇した溶鋼４は他
方の下降浸漬管７を下降して取鍋３内に戻される。本発
明では脱ガス処理開始時間から終了までArとの混合ガス
中のＮ2 ガス混合割合を一定にして還流ガス吹き込み管
から溶鋼４中に吹き込むことによって溶鋼中の溶存窒素
Ｎを取鍋目標Ｎに調整する。The N 2 gas contained in the mixed gas rising together with the molten steel 4 is melted into the molten steel 4 to increase the nitrogen content N. When the mixed gas rising together with the molten steel 4 is separated from the molten steel 4, the molten metal surface vigorously foams and splashes occur. The molten steel 4 thus raised in the degassing tank 2 is returned to the inside of the ladle 3 by moving down the other descending dipping pipe 7. In the present invention, the dissolved nitrogen in the molten steel is blown into the molten steel 4 from the reflux gas blowing pipe while keeping the N 2 gas mixing ratio in the mixed gas with Ar constant from the start time to the end of the degassing process.
Adjust N to the ladle target N.
【００１６】図１に示す還流式真空脱ガス装置を用い
て、取鍋内溶鋼の脱ガス終了後の取鍋目標Ｎ含有量を 7
0ppm、脱ガス処理前の測定Ｎ含有量が 60ppmとする場
合、すなわちその差ΔＮ＝ 10ppmに基づいて、還流ガス
流量1000l ／分でArとの混合ガス中のＮ2 ガス混合割合
を図２に基づき、Ｎ2 混合割合85％、Ar混合割合15％と
決定する。Using the reflux type vacuum degassing apparatus shown in FIG. 1, the ladle target N content after the degassing of the molten steel in the ladle was set to 7
When the measured N content before degassing is 60 ppm, that is, the difference ΔN = 10 ppm, the N 2 gas mixing ratio in the mixed gas with Ar at a reflux gas flow rate of 1000 l / min is shown in FIG. Based on this, it is determined that the N 2 mixing ratio is 85% and the Ar mixing ratio is 15%.
【００１７】このようなＮ2 ガス混合割合一定の混合ガ
スを還流ガスとして還流ガス吹き込み管から上昇浸漬管
内に吹き込んで溶鋼を20分間脱ガス処理することによ
り、脱ガス処理終了時の溶鋼Ｎ含有量を 71ppmに調整す
ることができ、的中率よく加窒することができた。な
お、前記実施例では脱ガス処理前の溶鋼に窒素を添加し
て加窒する場合を主体にして説明したが取鍋内の溶鋼の
脱ガス処理前の測定Ｎ含有量が取鍋目標Ｎより高い場合
にはArとの混合ガス中の窒素ガス混合割合を低くするこ
とによりＮ2ガスからの加窒と脱ガス処理時の溶鋼の脱
窒とのバランスにより溶鋼Ｎを低下させることも可能で
ある。By blowing such a mixed gas having a constant N 2 gas mixing ratio as a reflux gas from the reflux gas blowing pipe into the ascending dipping pipe to degas the molten steel for 20 minutes, the molten steel containing N at the end of the degassing treatment is contained. The amount could be adjusted to 71ppm, and it was possible to nitrify with good accuracy. In addition, in the said Example, although it demonstrated mainly when adding nitrogen to the molten steel before degassing and nitrifying, the measured N content before degassing of the molten steel in a ladle is more than the ladle target N. When it is high, it is possible to lower the molten steel N by lowering the nitrogen gas mixing ratio in the mixed gas with Ar to balance the nitrification from the N 2 gas and the denitrification of the molten steel during the degassing process. is there.
【００１８】[0018]
【発明の効果】以上説明したように本発明では還流式真
空脱ガス装置の上昇浸漬管に吹き込む還流ガスとしてAr
とＮ2 との混合ガスを用いて溶鋼中のＮ含有量を調整す
るようにしたから、脱ガス処理時間がばらついた場合で
も溶鋼中のＮ含有量を±5ppm程度で的中率よく調整する
ことができる。As described above, according to the present invention, Ar is used as the reflux gas blown into the ascending dip tube of the reflux type vacuum degassing apparatus.
Since the N content in molten steel was adjusted using a mixed gas of N and N 2 , even if the degassing treatment time varies, the N content in molten steel is adjusted within ± 5 ppm with good accuracy. be able to.
【図１】本発明に係る還流式真空脱ガス装置の縦断面図
である。FIG. 1 is a vertical sectional view of a reflux type vacuum degassing apparatus according to the present invention.
【図２】ΔＮ＝〔取鍋目標Ｎ−脱ガス処理前Ｎ〕とArと
の混合ガス中の混合割合との関係を示すグラフである。[Figure 2] .DELTA.N = - is a graph showing the relationship between the mixing ratio of mixed gas of [ladle target N degassing pretreatment N] and Ar.
【図３】従来のＲＨ脱ガス過程における鋼中のＮの推移
を示すグラフである。FIG. 3 is a graph showing a transition of N in steel during a conventional RH degassing process.
１ 還流式真空脱ガス装置 ２ 脱ガス槽 ３ 取鍋 ４ 溶鋼 ５ 排気ダクト ６ 上昇浸漬管 ７ 下降浸漬管 ８ 還流ガス吹き込み管 1 Reflux type vacuum degassing device 2 Degassing tank 3 Ladle 4 Molten steel 5 Exhaust duct 6 Upward dipping pipe 7 Downward dipping pipe 8 Recirculating gas blowing pipe
Claims (1)
と下降浸漬管とを取鍋内の溶鋼中に浸漬し、減圧された
脱ガス槽内に取鍋から溶鋼を吸い上げ、上昇浸漬管に還
流ガスを吹き込むことにより取鍋と脱ガス槽との間に溶
鋼を循環させるようにした溶鋼の真空脱ガス処理方法に
おいて、前記上昇浸漬管に吹き込む還流ガスとしてArと
Ｎ2 とを混合したガスを用い、該混合ガスのＮ2 ガス混
合割合を、取鍋内における溶鋼の脱ガス処理前の測定Ｎ
含有量と脱ガス処理終了後の目標Ｎ含有量との差に基づ
いて決定し、この決定したＮ2 ガス混合割合を有するAr
との混合ガスを上昇浸漬管に吹き込むことによって脱ガ
ス処理終了後の溶鋼のＮ含有量を目標Ｎ含有量範囲に的
中させることを特徴とする溶鋼の真空脱ガス処理方法。1. An ascending dip pipe and a descending dip pipe arranged at the bottom of a degassing tank are immersed in molten steel in a ladle, and the molten steel is sucked up from the ladle into a depressurized degassing tank and rises. In a vacuum degassing treatment method for molten steel, in which molten steel is circulated between a ladle and a degassing tank by blowing reflux gas into the immersion pipe, Ar and N 2 are used as reflux gas to be blown into the rising immersion pipe. Using the mixed gas, the N 2 gas mixing ratio of the mixed gas was measured N before degassing the molten steel in the ladle.
Ar based on the difference between the content and the target N content after completion of the degassing treatment and having the determined N 2 gas mixing ratio
A method for vacuum degassing of molten steel, characterized in that the N content of the molten steel after the degassing treatment is brought into the target N content range by blowing a mixed gas of the above into an ascending dip tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17351992A JPH0617113A (en) | 1992-06-30 | 1992-06-30 | Vacuum degassing method for molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17351992A JPH0617113A (en) | 1992-06-30 | 1992-06-30 | Vacuum degassing method for molten steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0617113A true JPH0617113A (en) | 1994-01-25 |
Family
ID=15962034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17351992A Pending JPH0617113A (en) | 1992-06-30 | 1992-06-30 | Vacuum degassing method for molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0617113A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009263783A (en) * | 2008-03-31 | 2009-11-12 | Jfe Steel Corp | Method for refining molten steel in rh vacuum degassing apparatus |
| CN101611182B (en) | 2006-12-15 | 2012-08-01 | 帝人高科技产品株式会社 | Heterocyclic aromatic polyamide fiber, its preparation method, cloth made of the fiber, and fiber-reinforced composite material reinforced by the fiber |
| KR101456448B1 (en) * | 2013-02-05 | 2014-10-31 | 주식회사 포스코 | Refining method of steel |
| KR20160063096A (en) * | 2014-11-26 | 2016-06-03 | 현대제철 주식회사 | Degassing apparatus and method |
-
1992
- 1992-06-30 JP JP17351992A patent/JPH0617113A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101611182B (en) | 2006-12-15 | 2012-08-01 | 帝人高科技产品株式会社 | Heterocyclic aromatic polyamide fiber, its preparation method, cloth made of the fiber, and fiber-reinforced composite material reinforced by the fiber |
| JP2009263783A (en) * | 2008-03-31 | 2009-11-12 | Jfe Steel Corp | Method for refining molten steel in rh vacuum degassing apparatus |
| KR101456448B1 (en) * | 2013-02-05 | 2014-10-31 | 주식회사 포스코 | Refining method of steel |
| KR20160063096A (en) * | 2014-11-26 | 2016-06-03 | 현대제철 주식회사 | Degassing apparatus and method |
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