JPH05287357A - Ultra low carbon steel melting method - Google Patents
Ultra low carbon steel melting methodInfo
- Publication number
- JPH05287357A JPH05287357A JP8376192A JP8376192A JPH05287357A JP H05287357 A JPH05287357 A JP H05287357A JP 8376192 A JP8376192 A JP 8376192A JP 8376192 A JP8376192 A JP 8376192A JP H05287357 A JPH05287357 A JP H05287357A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- gas
- lance
- ladle
- low carbon
- 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.)
- Withdrawn
Links
- 229910001209 Low-carbon steel Inorganic materials 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 title claims description 18
- 238000002844 melting Methods 0.000 title claims description 8
- 230000008018 melting Effects 0.000 title claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 44
- 239000010959 steel Substances 0.000 claims abstract description 44
- 239000007789 gas Substances 0.000 claims abstract description 39
- 239000011261 inert gas Substances 0.000 claims abstract description 9
- 238000005261 decarburization Methods 0.000 claims description 19
- 238000007664 blowing Methods 0.000 claims description 9
- 238000002347 injection Methods 0.000 abstract description 6
- 239000007924 injection Substances 0.000 abstract description 6
- 238000009849 vacuum degassing Methods 0.000 abstract description 2
- 238000007598 dipping method Methods 0.000 abstract 2
- 238000006243 chemical reaction Methods 0.000 description 18
- 229910052799 carbon Inorganic materials 0.000 description 5
- 230000001737 promoting effect Effects 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000007872 degassing Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000003483 aging Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、溶鋼を装入した取鍋全
体を真空槽内に装入し、減圧下において溶鋼の脱ガス処
理を実施する装置（以下、取鍋型脱ガス装置と記す）に
おいて、溶鋼中の炭素（以下、［Ｃ］と記す）の含有量
を極微量、例えば、０．００１ｍａｓｓ％以下まで除去
し、極低炭素鋼を溶製するための効率的かつ経済的な極
低炭素鋼の溶製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 an apparatus for charging a whole ladle charged with molten steel into a vacuum chamber and performing degassing treatment of molten steel under reduced pressure (hereinafter referred to as ladle type degassing apparatus). In the above), the content of carbon (hereinafter, referred to as [C]) in the molten steel is removed to an extremely small amount, for example, 0.001 mass% or less, and it is efficient and economical for producing an extremely low carbon steel. The present invention relates to a method for melting a very low carbon steel.
【０００２】[0002]
【従来の技術】取鍋型脱ガス装置における極低炭素鋼溶
製方法として本発明者らは、溶鋼中にランスを浸漬し、
不活性ガスを吹込むとともに、取鍋底部に設置したガス
吹込み口より不活性ガスを吹込む方法（特開平０３−２
８１７１８）をすでに考案している。この方法により、
２０分間の脱炭処理で、［Ｃ］濃度が０．００１〜０．
００１５ｍａｓｓ％の極低炭素鋼を製造する技術を確立
している。しかしながら、最近、極低炭素鋼の加工性向
上、時効硬化防止の観点からさらなる極低炭素化の要求
が強くなってきており、これに対応していくことを考慮
すると、上記方法では、必ずしも十分とは言えない。2. Description of the Related Art As a method for melting ultra-low carbon steel in a ladle-type degassing apparatus, the inventors of the present invention immersed a lance in molten steel,
A method of blowing an inert gas, and at the same time, blowing the inert gas from a gas inlet provided at the bottom of the ladle (Japanese Patent Laid-Open No. 03-2
81718) has already been devised. By this method,
After 20 minutes of decarburization, the [C] concentration was 0.001 to 0.
We have established the technology to manufacture ultra low carbon steel with 0015 mass%. However, recently, from the viewpoints of workability improvement of ultra-low carbon steel and prevention of age hardening, there is a strong demand for further ultra-low carbon, and in view of responding to this, the above method is not always sufficient. It can not be said.
【０００３】[0003]
【発明が解決しようとする課題】前記の取鍋底部に設置
したガス吹込み口より不活性ガスを吹込む方法において
は、ガス吹込み口付近の耐火物の溶損が大きく、鍋の補
修・整備に手間がかかり、生産性に悪影響を及ぼす。さ
らにポーラスプラグを用いてガスを溶鋼に吹込む場合に
は、大量のガスを吹込むためには、多数のポーラスプラ
グを設置することが必要になり、ますます鍋の整備に手
間がかかる。このように従来以上の脱炭を促進すること
は容易ではない。In the method of injecting an inert gas from the gas inlet provided at the bottom of the ladle, the melting loss of the refractory near the gas inlet is large, and the pot repair / It takes time and effort to maintain it, which adversely affects productivity. Furthermore, in the case of blowing gas into molten steel using a porous plug, it is necessary to install a large number of porous plugs in order to blow a large amount of gas, and it becomes more and more troublesome to maintain the pot. In this way, it is not easy to promote decarburization more than ever before.
【０００４】[0004]
【課題を解決するための手段】本発明は、上記課題を解
決するため、減圧下において、溶鋼の脱炭処理を実施す
るにあたり、真空槽５内の溶鋼１にガス噴出方向が互い
に逆向きの２つのガス噴出口２Ａ，２Ｂを有するランス
３を溶鋼１に浸漬し、Ｔをガス噴出口２Ａ，２Ｂからの
気泡の発生周期，ｎを自然数としたとき、 （４ｎ−３）π／（４Ｔ）＜ω＜（４ｎ−１）π／（４
Ｔ） を満たす角速度ωでランス（３）をその中心軸の周りに
回転させながら不活性ガスを吹込むことを特徴とする極
低炭素鋼の溶製方法、を提供するものである。In order to solve the above-mentioned problems, according to the present invention, when decarburizing the molten steel under reduced pressure, the gas jetting directions in the molten steel 1 in the vacuum tank 5 are opposite to each other. When the lance 3 having the two gas ejection ports 2A and 2B is immersed in the molten steel 1 and T is the generation period of bubbles from the gas ejection ports 2A and 2B and n is a natural number, (4n-3) π / (4T ) <Ω <(4n-1) π / (4
The present invention provides a method for melting ultra-low carbon steel, which comprises blowing an inert gas while rotating the lance (3) around its central axis at an angular velocity ω satisfying T).
【０００５】[0005]
【作用】以下、本発明について詳細に述べる。一般に、
減圧下での溶鋼の脱炭反応は、大きくつぎの３種類に分
類される。すなわち、 溶鋼内部、耐火物表面で［Ｃ］と酸素（以下、［Ｏ］
と記す）との反応、この場合はＣＯ気泡の発生を伴う。 減圧雰囲気にさらされている溶鋼自由表面での、
［Ｃ］と［Ｏ］との反応。 溶鋼中に吹込まれたアルゴン気泡と溶鋼との界面で起
こる［Ｃ］と［Ｏ］との反応。 とに分類される。これらの反応の内、［Ｃ］濃度が０．
０２０ｍａｓｓ％超の領域ではの反応が主体であるこ
とが明らかにされている。この領域では、溶鋼内部から
ＣＯ気泡発生が活発に起こっており、Ａｒガスを溶鋼中
に分散させて、気・液反応界面積を拡大しても脱炭反応
の促進には効果が小さい。The present invention will be described in detail below. In general,
The decarburization reaction of molten steel under reduced pressure is roughly classified into the following three types. That is, [C] and oxygen (hereinafter referred to as [O] in the molten steel and refractory surface.
With the formation of CO bubbles. On the free surface of molten steel exposed to a reduced pressure atmosphere,
Reaction between [C] and [O]. Reaction between [C] and [O] occurring at the interface between the molten steel and argon bubbles blown into the molten steel. Classified as and. Among these reactions, the [C] concentration was 0.
It has been clarified that the reaction is dominant in the region of more than 020 mass%. In this region, CO bubbles are actively generated from inside the molten steel, and even if Ar gas is dispersed in the molten steel to increase the gas-liquid reaction interface area, the effect of promoting the decarburization reaction is small.
【０００６】［Ｃ］濃度が０．０２０ｍａｓｓ％以下、
０．００５ｍａｓｓ％超の領域では、の反応の割合が
［Ｃ］濃度の低下とともに小さくなり、気・液反応界面
積を増大させ脱炭反応を促進させるため、吹込みＡｒガ
スを分散させることは重要であるが、Ａｒガス分散によ
る脱炭反応促進効果は不十分である。[C] concentration is 0.020 mass% or less,
In the region of more than 0.005 mass%, the ratio of the reaction of becomes smaller as the concentration of [C] decreases and the gas-liquid reaction boundary area increases to promote the decarburization reaction. Although important, the decarburization reaction promoting effect of Ar gas dispersion is insufficient.
【０００７】一方、［Ｃ］濃度が０．００５ｍａｓｓ％
以下の領域では、脱炭反応は、の溶鋼自由表面及び
のアルゴン気泡と溶鋼との界面での反応が主体となる。
この領域では、溶鋼中に吹込むＡｒガスの流量を多くす
るとともに、吹込まれたＡｒ気泡を溶鋼中に分散させて
気・液反応界面積を大きくすることが脱炭反応の促進に
は特に重要である。On the other hand, the [C] concentration is 0.005 mass%
In the following region, the decarburization reaction mainly consists of the reaction at the free surface of the molten steel and at the interface between the argon bubbles and the molten steel.
In this region, increasing the flow rate of Ar gas blown into the molten steel and dispersing the blown Ar bubbles in the molten steel to increase the gas-liquid reaction interface area are particularly important for promoting the decarburization reaction. Is.
【０００８】本発明者は、溶鋼中にＡｒガスを分散する
ための方法として溶鋼中にランスを浸漬し、ランスを回
転させながらＡｒガスを吹込む方法を検討した。The present inventor has examined a method for dispersing Ar gas in molten steel by immersing the lance in the molten steel and blowing Ar gas while rotating the lance.
【０００９】図１は、本発明の実施様態を示す図であ
る。すなわち、減圧下において、溶鋼の脱炭処理を実施
するにあたり、真空槽５内の溶鋼１にガス噴出方向が互
いに逆向きの２つのガス噴出口２Ａ，２Ｂを有するラン
ス３を溶鋼１に浸漬し、ランス３をその中心軸の周りに
回転させながら不活性ガスを吹込むことによりＡｒ気泡
を溶鋼中に分散させる。FIG. 1 is a diagram showing an embodiment of the present invention. That is, when performing decarburization treatment of molten steel under reduced pressure, a lance 3 having two gas ejection ports 2A and 2B whose gas ejection directions are opposite to each other is immersed in the molten steel 1 in the vacuum tank 5. The Ar bubbles are dispersed in the molten steel by blowing an inert gas while rotating the lance 3 around its central axis.
【００１０】Ａｒ気泡を溶鋼中に分散させるにあたり、
ランス３の回転速度は重要である。In dispersing Ar bubbles in molten steel,
The rotation speed of the lance 3 is important.
【００１１】図２は、ランスの回転の角速度ωと脱炭反
応の容量係数ｋｃとの関係を示した図である。ここで、
脱炭反応の容量係数は（１）式で定義される。FIG. 2 is a diagram showing the relationship between the angular velocity ω of rotation of the lance and the capacity coefficient kc of the decarburization reaction. here,
The capacity coefficient of the decarburization reaction is defined by the equation (1).
【００１２】 −ｄ［ｍａｓｓ％Ｃ］／ｄｔ＝・［ｍａｓｓ％Ｃ］ （１） ただし、［ｍａｓｓ％Ｃ］は［Ｃ］濃度、ｔは時間であ
る。-D [mass% C] / dt = · [mass% C] (1) where [mass% C] is the [C] concentration and t is time.
【００１３】気泡発生周期をＴとすると、ω＝ｎπ／Ｔ
（ｎは自然数）のときはＡｒガスが一定の方向にしか噴
出されず、噴出された気泡が容易に合体するため、脱炭
促進効果は小さい。それに対して、角速度ωを（２）式
の範囲にしたときはＡｒガスがいろいろな方向に噴出さ
れ、気泡が取鍋内に分散されるため脱炭促進効果が大き
く、ガスをランス３を回転しない場合に比べて約５倍ｋ
ｃが大きくなっている。Assuming that the bubble generation period is T, ω = nπ / T
When (n is a natural number), the Ar gas is ejected only in a certain direction, and the ejected bubbles are easily combined, so that the decarburization promoting effect is small. On the other hand, when the angular velocity ω is set in the range of the formula (2), Ar gas is ejected in various directions and bubbles are dispersed in the ladle, so that the decarburization promoting effect is large and the gas is rotated by the lance 3. Approximately 5 times more k than without
c is large.
【００１４】 （４ｎ−３）π／（４Ｔ）＜ω＜（４ｎ−１）π／（４Ｔ） （２） 以上、溶鋼の脱炭処理に本発明の方法を適用する場合に
ついて説明したが、本発明の方法は、脱炭ならず、溶鋼
の脱窒、脱水素にも有効である。(4n-3) π / (4T) <ω <(4n-1) π / (4T) (2) The case of applying the method of the present invention to the decarburization treatment of molten steel has been described above. The method of the present invention is effective for denitrification and dehydrogenation of molten steel without decarburization.
【００１５】さらに、本発明の方法は、ＲＨ，ＤＨのよ
うに取鍋内の溶鋼の一部を真空槽内に吸い上げて脱炭処
理を行う装置においても真空槽内の溶鋼にＡｒガスを吹
込む方法として有効である。Further, according to the method of the present invention, Ar gas is blown to the molten steel in the vacuum tank even in an apparatus for decarburizing by sucking a part of the molten steel in the ladle into the vacuum tank like RH and DH. It is effective as a way to get in.
【００１６】[0016]
【実施例】初期成分が［Ｃ］；０．０２ｍａｓｓ％，
［Ｓｉ］；０．１ｍａｓｓ％以下、［Ｍｎ］；０．０１
〜０．５ｍａｓｓ％，［Ｐ］；０．００５〜０．０２ｍ
ａｓｓ％、［Ｓ］；０．００３〜０．００５ｍａｓｓ
％，［Ａｌ］；０．００２ｍａｓｓ％以下の溶鋼の脱炭
実験を真空溶解炉を用いて実施した。溶鋼１中にランス
３を浸漬し、ガス噴出口２Ａ，２Ｂより互いに逆向きに
Ａｒガスを溶鋼中に吹込んだ。[Example] The initial component is [C]; 0.02 mass%,
[Si]; 0.1 mass% or less, [Mn]; 0.01
~ 0.5mass%, [P]; 0.005-0.02m
% ass, [S]; 0.003 to 0.005 mass
%, [Al]; 0.002 mass% or less decarburization experiment of molten steel was carried out using a vacuum melting furnace. The lance 3 was immersed in the molten steel 1, and Ar gas was blown into the molten steel in opposite directions from the gas ejection ports 2A and 2B.
【００１７】溶鋼重量は１００ｋｇで、槽内の圧力は１
７０ｍｍＨｇである。ガス噴出口の直径は０．００２
ｍ，吹込み深さは０．２５ｍ，吹込みガス流量は毎分２
Ｎｌ，ガス噴出口の数は２個である。The weight of molten steel is 100 kg and the pressure in the tank is 1.
It is 70 mmHg. The diameter of the gas outlet is 0.002
m, blowing depth is 0.25 m, blowing gas flow rate is 2 per minute
The number of Nl and gas ejection ports is two.
【００１８】気泡発生周期Ｔは、気泡直径を（３）式の
Davidson and Amickの式（Journalof American Institu
te of Chemical Engineering,vol.2(1956),p.337）を用
いて計算し、気泡１個当りの体積と、ガス噴出口１個当
りの吹込みガス流量から（４）式で求めた。The bubble generation period T is defined by the bubble diameter expressed by equation (3).
Davidson and Amick's formula (Journal of American Institu
te of Chemical Engineering, vol.2 (1956), p.337) and calculated from the volume per bubble and the flow rate of gas blown into each gas outlet according to equation (4).
【００１９】[0019]
【数１】 [Equation 1]
【００２０】ここで、ＤB は気泡直径（ｍ），Ｑはガス
噴出口１個当りの吹込みガス流量（ｍ3 ／ｓ），ｄN は
ガス噴出口の直径（ｍ）を表わす。本実施例の条件で
は、気泡発生周期は約０．０１秒であった。Here, D B is the bubble diameter (m), Q is the flow rate of gas blown per gas outlet (m 3 / s), and d N is the diameter (m) of the gas outlet. Under the conditions of this example, the bubble generation period was about 0.01 seconds.
【００２１】図３に［Ｃ］濃度の経時変化を示す。本発
明の方法では、２５πラジアン／秒の角速度でランスを
回転させた。比較例は、ランスを５０πラジアン／秒で
回転した場合である。２０分の脱炭処理後の［Ｃ］の濃
度は、比較例では０．００１５ｍａｓｓ％であるのに対
して本発明の方法では、０．０００７ｍａｓｓ％まで達
した。FIG. 3 shows the change with time of the [C] concentration. In the method of the present invention, the lance was rotated at an angular velocity of 25π radians / second. The comparative example is when the lance is rotated at 50π radians / second. The concentration of [C] after the decarburization treatment for 20 minutes was 0.0015 mass% in the comparative example, while it reached 0.0007 mass% in the method of the present invention.
【００２２】[0022]
【発明の効果】本発明により、取鍋４全体を真空槽５内
に装入し、溶鋼１中に不活性ガスを吹込む方式の真空脱
ガス装置において、従来の様な、ポーラスプラグによる
ガス吹込み方法ではなく、所定の回転速度で旋回するラ
ンス３によるガス吹込み方法により、溶損の大きいポー
ラスプラグに起因する鍋の修理・整備に掛かる手間を省
く事ができ、更に、吹込みガス流量も容易に増大する事
ができるので［Ｃ］濃度が、０．００１％以下の極低炭
素鋼を容易に出来る様になった。According to the present invention, in the vacuum degassing apparatus of the type in which the entire ladle 4 is charged into the vacuum tank 5 and the inert gas is blown into the molten steel 1, the gas by the porous plug as in the conventional case is used. By using the gas injection method using the lance 3 that swirls at a predetermined rotation speed instead of the injection method, it is possible to save the trouble of repairing and servicing the pan due to the porous plug with large melting loss. Since the flow rate can be easily increased, it became possible to easily produce an ultra low carbon steel having a [C] concentration of 0.001% or less.
【図１】本発明の方法の実施様態を示す図。FIG. 1 is a diagram showing an embodiment of the method of the present invention.
【図２】脱炭反応の容量係数とランス回転の角速度との
関係を示す図。FIG. 2 is a diagram showing a relationship between a capacity coefficient of a decarburization reaction and an angular velocity of lance rotation.
【図３】［Ｃ］濃度の経時変化を示す図。FIG. 3 is a view showing a change with time of [C] concentration.
１…溶鋼 ２Ａ，２Ｂ…ガス
噴出口 ３…ランス ４Ａ…取鍋 ５…真空槽1 ... Molten steel 2A, 2B ... Gas ejection port 3 ... Lance 4A ... Ladle 5 ... Vacuum tank
Claims (1)
するにあたり、真空槽（５）内の溶鋼（１）にガス噴出
方向が互いに逆向きの２つのガス噴出口（２Ａ），（２
Ｂ）を有するランス（３）を溶鋼（１）に浸漬し、Ｔを
ガス噴出口（２Ａ），（２Ｂ）からの気泡の発生周期，
ｎを自然数としたとき、 （４ｎ−３）π／（４Ｔ）＜ω＜（４ｎ−１）π／（４
Ｔ） を満たす角速度ωでランス（３）をその中心軸の周りに
回転させながら不活性ガスを吹込むことを特徴とする極
低炭素鋼の溶製方法。1. When carrying out decarburization treatment of molten steel under reduced pressure, two gas ejection ports (2A), (2) having opposite gas ejection directions to the molten steel (1) in a vacuum tank (5) are provided.
The lance (3) having B) is immersed in the molten steel (1), and T is a cycle of generation of bubbles from the gas jet ports (2A) and (2B).
When n is a natural number, (4n−3) π / (4T) <ω <(4n−1) π / (4
T) A method for melting ultra-low carbon steel, which comprises blowing an inert gas while rotating the lance (3) around its central axis at an angular velocity ω satisfying
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8376192A JPH05287357A (en) | 1992-04-06 | 1992-04-06 | Ultra low carbon steel melting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8376192A JPH05287357A (en) | 1992-04-06 | 1992-04-06 | Ultra low carbon steel melting method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05287357A true JPH05287357A (en) | 1993-11-02 |
Family
ID=13811562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8376192A Withdrawn JPH05287357A (en) | 1992-04-06 | 1992-04-06 | Ultra low carbon steel melting method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05287357A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5902374A (en) * | 1995-08-01 | 1999-05-11 | Nippon Steel Corporation | Vacuum refining method for molten steel |
-
1992
- 1992-04-06 JP JP8376192A patent/JPH05287357A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5902374A (en) * | 1995-08-01 | 1999-05-11 | Nippon Steel Corporation | Vacuum refining method for molten steel |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990608 |