JPH0742524B2 - Method for cleaning molten metal - Google Patents
Method for cleaning molten metalInfo
- Publication number
- JPH0742524B2 JPH0742524B2 JP63250807A JP25080788A JPH0742524B2 JP H0742524 B2 JPH0742524 B2 JP H0742524B2 JP 63250807 A JP63250807 A JP 63250807A JP 25080788 A JP25080788 A JP 25080788A JP H0742524 B2 JPH0742524 B2 JP H0742524B2
- Authority
- JP
- Japan
- Prior art keywords
- molten metal
- gas
- bubbling
- pressure
- gas bubbles
- 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.)
- Expired - Fee Related
Links
Landscapes
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、溶融金属中に浮遊する介在物を除去する溶
融金属の清浄化方法に関する。TECHNICAL FIELD The present invention relates to a method for cleaning molten metal, which removes inclusions floating in the molten metal.
溶融金属中に浮遊する介在物（例えば溶鋼中のアルミナ
系介在物）は、製品品質欠陥の原因となるため、その低
減・除去方法が種々提案されている。Inclusions floating in the molten metal (for example, alumina-based inclusions in molten steel) cause defects in product quality, and various reduction / removal methods have been proposed.
本発明者等は、高級材製造を目的とした場合溶鋼中のト
ータル酸素量は15ppm以下に抑える必要があるとの要請
に鑑み、次のような提案を行なつた。即ち、加圧状態に
した溶融金属を、それに可溶なガスでバブリングして該
溶融金属中にガスを溶解せしめ、その後急速に減圧して
溶融金属中に微細ガス気泡を発生させるというものであ
る。この方法によれば溶融金属中の通常の介在物は最初
のバブリングでそのガス気泡にトラツプされ浮上せしめ
られることになる。他方、このバブリングは加圧した溶
融金属に対して行なわれるため、バブリングガスが多量
に溶融金属中に溶け込むことになる。その後の急速な減
圧で、溶融金属中に溶け込んでいたガスが微細なガス気
泡となつて溶融金属全域から発生する。この時、微細な
介在物は該ガス気泡にトラツプされて浮上する。The present inventors have made the following proposal in view of the demand that the total amount of oxygen in molten steel should be suppressed to 15 ppm or less for the purpose of producing high-grade materials. That is, the molten metal in a pressurized state is bubbled with a gas soluble in the molten metal to dissolve the gas in the molten metal, and then the pressure is rapidly reduced to generate fine gas bubbles in the molten metal. . According to this method, ordinary inclusions in the molten metal are trapped and floated by the gas bubbles at the first bubbling. On the other hand, since the bubbling is performed on the molten metal which is pressurized, a large amount of the bubbling gas is dissolved in the molten metal. By the rapid depressurization thereafter, the gas dissolved in the molten metal becomes fine gas bubbles and is generated from the entire molten metal. At this time, the fine inclusions are trapped by the gas bubbles and float up.
又本発明者等は、溶融金属中に多量に溶け残つているバ
ブリングガスの脱ガスを別処理工程として行なうことな
く、上記のような清浄化処理工程中で一緒に行なうこと
ができるようにするため、更にその処理技術の改良を行
なつた。Further, the inventors of the present invention make it possible to carry out the degassing of the bubbling gas which remains in the molten metal in a large amount as a separate processing step together with the degassing in the above-mentioned cleaning processing step. Therefore, the processing technology was further improved.
即ち上記の方法では、ガスバブリング時に溶融金属を加
圧していることが原因となり、初期の溶融金属中の該ガ
ス濃度が高く、限られた時間内で処理しただけでは溶融
金属中に該ガスの一部が溶け残つてしまうため、その対
策としてバブリング時の加圧処理を止め、大気圧又はそ
れ以下の状態でバブリングすることとし、その後に減圧
処理を行なうというものである。この改良型の方法では
減圧処理によつて微細ガス気泡が発生せしめられるだけ
でなく、製品として要望される溶融金属中の脱ガスも一
緒に行なわれることになる。That is, in the above method, the molten metal is pressurized at the time of gas bubbling, and the concentration of the gas in the molten metal at the beginning is high. Since part of the material remains undissolved, as a countermeasure against this, the pressure treatment at the time of bubbling is stopped, and bubbling is performed under atmospheric pressure or lower, and then pressure reduction treatment is performed. In this improved method, not only fine gas bubbles are generated by the reduced pressure treatment, but also degassing in the molten metal required as a product is also performed.
上記したいずれの方法とも溶融金属中の介在物を除去す
るには効率の良い方法であるが、溶解したガスが減圧に
より再び発生して微細ガス気泡となるガス発生量は時間
と共に減少し、浮上効果が減少してしまうという問題が
あつた。Although any of the above methods is an efficient method for removing inclusions in the molten metal, the amount of gas generated when the dissolved gas is regenerated by depressurization to form fine gas bubbles decreases with time, and it floats. There was a problem that the effect would decrease.
本発明は以上のような問題に鑑み創案されたもので、上
記の両方法を改良し、減圧時にも浮上効果が低下しない
ようにするものである。The present invention was devised in view of the above problems, and improves both of the above methods so that the levitation effect does not decrease even during depressurization.
そのため本発明は、上記の両方法を夫々実施するに当
り、減圧時にも該溶融金属に可溶なガスをバブリングす
ることを基本的特徴とするものである。Therefore, the present invention is basically characterized by bubbling a gas soluble in the molten metal even when the pressure is reduced, in carrying out both of the above methods.
減圧時にも溶融金属に可溶なガスをバブリングすること
で、そのバブリングガスのガス気泡による介在物のトラ
ツプと、微小ガス気泡発生による微小介在物のトラツプ
が継続して行なわれ、介在物浮上効果が長時間に亘り得
られることになる。By bubbling a gas soluble in the molten metal even during depressurization, trapping of inclusions due to gas bubbles of the bubbling gas and trapping of small inclusions due to generation of minute gas bubbles are continuously performed, and the effect of floating inclusions is increased. Will be obtained over a long period of time.
以下本発明の具体的実施例につき説明する。まず、加圧
状態でバブリングしその後減圧する方法について本発明
者は次のような実験を行なつた。Specific examples of the present invention will be described below. First, the present inventor conducted the following experiment on a method of bubbling under pressure and then depressurizing.
50tonの加圧容器に溶鋼50tonを入れフタをする。そして
内部雰囲気をアルゴンガスで置換する。その後該加圧容
器の底から（Ar:70％,H2:30％）の混合ガスを、200/m
inの吹込み速度で20分間ガスバブリングする。この時、
容器内のガス圧は3atmになるように調圧弁で制御する。
バブリング終了後、大気圧にまで減圧し、発生したガス
気泡が浮上するまで約20分間放置する。Put 50 tons of molten steel in a 50 tons pressure vessel and cover. Then, the internal atmosphere is replaced with argon gas. Then, from the bottom of the pressure vessel, (Ar: 70%, H 2 : 30%) mixed gas, 200 / m
Gas bubble for 20 minutes at an insufflation rate. At this time,
The gas pressure in the container is controlled by the pressure regulating valve so that it becomes 3 atm.
After the bubbling is completed, the pressure is reduced to atmospheric pressure, and the gas bubbles are left for about 20 minutes until they float.
一方、これとは別に本願第１発明を実施した。即ち、上
記の加圧減圧法と略同一の処理を行ない、減圧時に容器
底部から上記と同一の混合ガスを100/minの速度で20
分間バブリングしている。On the other hand, the first invention of the present application was carried out separately. That is, substantially the same treatment as the pressurization and depressurization method described above is performed, and when depressurizing, the same mixed gas as described above is supplied from the bottom of the container at a speed of 100 / min for 20 minutes.
I'm bubbling for a minute.
図面は、上記二つの溶鋼処理による溶鋼中のトータル酸
素量の変化の推移を示すグラフ図である。同図によれ
ば、処理前トータル酸素量が80ppmあつた溶鋼が従前の
提案に係る加圧減圧法では15ppmとなつたのに対し、本
発明法では10ppmとなり、本発明法の方が溶鋼の清浄化
効果において更に優れていることがわかる。The drawing is a graph showing changes in the total oxygen content in molten steel due to the above two molten steel treatments. According to the figure, the total oxygen content before treatment was 80 ppm and the molten steel was 15 ppm in the pressure reduction method according to the previous proposal, whereas it was 10 ppm in the method of the present invention, and the method of the present invention is more It can be seen that the cleaning effect is further excellent.
次にバブリング時に加圧を行なわず、後に減圧する方法
につき、本発明者等は以下のような実験を行なつた。Next, the present inventors conducted the following experiment for a method of depressurizing without applying pressure during bubbling.
50tonVOD設備内で溶鋼50tonを1660℃で300torrに保ち、
取鍋底部よりポーラスプラグで10分間6Nm3のN2ガスを吹
き込んだ。その後VAD設備内に該溶鋼を移し、熱補償を
行ないながら急速に1torrまで減圧させ、20分間保持し
た。この時同時に取鍋底部からArガスを150Nl/minでバ
ブリングした。Keep 50ton of molten steel at 1660 ℃ and 300torr in 50ton VOD facility,
6 Nm 3 of N 2 gas was blown from the bottom of the ladle with a porous plug for 10 minutes. After that, the molten steel was transferred into a VAD facility, and while being thermally compensated, the pressure was rapidly reduced to 1 torr and kept for 20 minutes. At this time, Ar gas was bubbled from the bottom of the ladle at the same time at 150 Nl / min.
一方、上記と略同一の処理を行ない、減圧時に容器底部
から次のような条件でArガスとN2ガスの混合ガスを吹き
込んだ。On the other hand, substantially the same treatment as above was performed, and a mixed gas of Ar gas and N 2 gas was blown from the bottom of the container under the following conditions during depressurization.
以上の２つの方法を実施した時の溶鋼成分とＴ・〔Ｏ〕
及びＴ・〔Ｎ〕の成分変化を次の表２に示す。 Molten steel composition and T ・ [O] when the above two methods were carried out
Table 2 below shows changes in the components of T and [N].
上記表２から明らかなように、介在物除去能力について
は、大気圧以下でバブリングした後単に減圧する従前の
方法より本願第２発明法の方が優れていることがわか
る。 As is clear from Table 2 above, the second invention method of the present application is superior in the ability of removing inclusions to the conventional method of bubbling at atmospheric pressure or less and then simply depressurizing.
以上群述したように本発明法によれば減圧時にも溶融金
属に可溶なガスの吹き込みが行なわれるため、バブリン
グガス気泡による介在物のトラツプ及び発生する微細ガ
ス気泡による微小介在物のトラツプが継続して行なわれ
ることになり、該介在物除去能力が更に向上することに
なる。As described above, according to the method of the present invention, since the gas soluble in the molten metal is blown even during depressurization, trapping of inclusions due to bubbling gas bubbles and trapping of fine inclusions due to generated fine gas bubbles occur. It is carried out continuously, and the ability of removing the inclusions is further improved.
図面は加圧減圧法及びその改良に係る本願第１発明法に
より溶鋼を処理した場合の減圧処理開始後のＴ・〔Ｏ〕
量の推移を示すグラフ図である。The drawing shows T · [O] after the start of depressurization when a molten steel is processed by the pressurization / depressurization method and the method of the first invention of the present application related to the improvement.
It is a graph which shows the change of quantity.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 松野 秀寿 東京都千代田区丸の内１丁目１番２号 日 本鋼管株式会社内 (56)参考文献 特公 平５−5575（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hidetoshi Matsuno 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (56) References Japanese Patent Publication 5-5575 (JP, B2)
Claims (2)
ガスでバブリングして該溶融金属中にガスを溶解せし
め、その後急速に減圧して溶融金属中に微細ガス気泡を
発生させ、溶融金属中に浮遊する介在物をバブリングに
よるガス気泡及び減圧により発生した微細ガス気泡にト
ラツプせしめて、浮上後これを除去する溶融金属の清浄
化方法を実施するに当り、減圧時にも該溶融金属に可溶
なガスをバブリングすることを特徴とする溶融金属の清
浄化方法。1. A molten metal in a pressurized state is bubbled with a gas soluble therein to dissolve the gas in the molten metal, and then the pressure is rapidly reduced to generate fine gas bubbles in the molten metal. In carrying out a method for cleaning molten metal in which inclusions floating in molten metal are trapped by gas bubbles due to bubbling and fine gas bubbles generated by decompression, and are removed after floating, the molten metal is also decompressed. A method for cleaning molten metal, which comprises bubbling a gas soluble in water.
それに可溶なガスでバブリングして該溶融金属中にガス
を溶解せしめ、その後急速に減圧して溶融金属中に微細
ガス気泡を発生させると共にこの減圧で該溶融金属中に
溶け残つているバブリングガスの脱ガスを合わせて行な
い、溶融金属中に浮遊する介在物をバブリングによるガ
ス気泡及び減圧により発生した微細ガス気泡にトラップ
せしめて、浮上後これを除去する溶融金属の清浄化方法
を実施するに当り、減圧時にも該溶融金属に可溶なガス
をバブリングすることを特徴とする溶融金属の清浄化方
法。2. A molten metal is bubbled with a gas soluble in the molten metal under atmospheric pressure or lower to dissolve the gas in the molten metal, and then the pressure is rapidly reduced to generate fine gas bubbles in the molten metal. The degassing of the bubbling gas that remains undissolved in the molten metal under this reduced pressure is performed together, and the inclusions floating in the molten metal are trapped in the gas bubbles by bubbling and the fine gas bubbles generated by the reduced pressure, A method for cleaning a molten metal, wherein a gas soluble in the molten metal is bubbled even when the pressure is reduced in carrying out a method for cleaning the molten metal which removes the surface after floating.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63250807A JPH0742524B2 (en) | 1988-10-06 | 1988-10-06 | Method for cleaning molten metal |
| CA000614559A CA1339703C (en) | 1988-10-06 | 1989-09-29 | Method for cleaning molten metal |
| AU42457/89A AU4245789A (en) | 1988-10-06 | 1989-10-02 | Method for cleaning molten metal |
| DE8989118517T DE68905741T2 (en) | 1988-10-06 | 1989-10-05 | METHOD FOR CLEANING METAL. |
| EP89118517A EP0362851B1 (en) | 1988-10-06 | 1989-10-05 | Method for cleaning molten metal |
| BR898905068A BR8905068A (en) | 1988-10-06 | 1989-10-05 | METAL FUSION CLEANING PROCESS |
| KR1019890014420A KR920006578B1 (en) | 1988-10-06 | 1989-10-06 | Method for cleaning molten metal and apparatus therefor |
| US07/516,478 US5091000A (en) | 1987-12-25 | 1990-04-30 | Method for cleaning molten metal and apparatus therefor |
| AU13976/92A AU655245B2 (en) | 1988-10-06 | 1992-04-02 | Method for cleaning molten metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63250807A JPH0742524B2 (en) | 1988-10-06 | 1988-10-06 | Method for cleaning molten metal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0299264A JPH0299264A (en) | 1990-04-11 |
| JPH0742524B2 true JPH0742524B2 (en) | 1995-05-10 |
Family
ID=17213340
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63250807A Expired - Fee Related JPH0742524B2 (en) | 1987-12-25 | 1988-10-06 | Method for cleaning molten metal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0742524B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007138206A (en) * | 2005-11-16 | 2007-06-07 | Jfe Steel Kk | Method for highly purifying molten metal |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6021207B2 (en) * | 1981-05-26 | 1985-05-25 | 川崎製鉄株式会社 | Manufacturing method of ultra-low carbon molten steel |
| JPS61295314A (en) * | 1985-06-21 | 1986-12-26 | Nippon Kokan Kk <Nkk> | Method for accelerating floating of inclusion by drastic degassing with rh degassing device |
-
1988
- 1988-10-06 JP JP63250807A patent/JPH0742524B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0299264A (en) | 1990-04-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |