JPS5989705A - Refining method with top and bottom blown converter - Google Patents
Refining method with top and bottom blown converterInfo
- Publication number
- JPS5989705A JPS5989705A JP19803082A JP19803082A JPS5989705A JP S5989705 A JPS5989705 A JP S5989705A JP 19803082 A JP19803082 A JP 19803082A JP 19803082 A JP19803082 A JP 19803082A JP S5989705 A JPS5989705 A JP S5989705A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- oxygen
- stirring gas
- blowing
- stirring
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
Abstract
Description
本発明は上底吹転炉精錬方法に関し、その目的はＦｌ
ｅおよびＭｎの歩留りが良く、さらに脱Ｐ効率の優れた
精錬方法な提供することにある。
近時、歩留りおよび精錬反応効率の向上な目的として上
部ランスから酸素（０２）＆下部から攪拌ガスな吹込む
上底吹転炉精錬方法が実施されるよ５ ｙｃなった。
一方、鉄鋼需要の面から低Ｐ鋼が望まれ始め、この低Ｐ
鋼を上底吹転炉で溶製する方法が研究され始めたが、（
Ｐ）を下げようとすると（Ｍ ｎ ）も低くなり、逆に
（Ｍ ｎ ）を高めようとすると（Ｐ）も高くなると云
う二律背反の命題があり、（Ｐ）を下げ（Ｍｎ、）を高
めると云う操業が可能な方法は提案されていなかった。
そこで、本発明者等は前記問題点の解決ｆｃ努力した結
果、本発明を創出することによって低Ｐで高Ｍｎの溶鋼
を得ることを可能とした。
さて、上底吹転炉において、下部羽口または下部う〃か
ら吹込まれる攪拌ガス（窒素、アルゴン等の不活性ガス
、−酸化炭素や二酸化炭素、炭化水素や酸素などのうち
適宜なガスもしくは２種以上の適宜に混合されたガス）
の量を低めにして溶鋼の弱攪拌を実施すると、スラグ中
の鉄分（Ｆ’ｅ）が多くなって歩留りが低重する傾向が
あり、逆に攪拌ガスの吹込みｔ多くして強攪拌するとス
ラグ中のＦｅは減少しくＰ）も低下するものの（Ｍｎ）
の歩留りが著しく低下する傾向が認められる。
従って、従来の上底吹転炉精錬方法では、牙１図ｙｃ示
す通り、上部から酸素な、下部から攪拌ガスを吹込む（
以下底吹とも云う）吹錬期間（Ｗ）ｙｃおいて、攪拌ガ
ス量を吹錬初期では低目とし、吹錬末期The present invention relates to a top-bottom blowing converter refining method, the purpose of which is to
It is an object of the present invention to provide a refining method that has a high yield of e and Mn and also has an excellent dephosphorization efficiency. Recently, for the purpose of improving yield and refining reaction efficiency, a top-bottom blown converter refining method in which oxygen (02) is blown from the upper lance and stirring gas from the lower part has been implemented. On the other hand, from the perspective of steel demand, demand for low P steel began to rise, and this low P steel
Research began on a method of melting steel in a top-bottom blowing converter, but (
There is a contradictory proposition that if you try to lower P), (M n ) will also decrease, and conversely, if you try to increase (M n ), (P) will also increase. No method has been proposed that would allow this kind of operation. Therefore, the inventors of the present invention made efforts to solve the above-mentioned problems, and as a result of creating the present invention, it became possible to obtain molten steel with low P and high Mn. Now, in an upper-bottom blowing converter, a stirring gas (inert gas such as nitrogen, argon, etc., an appropriate gas such as carbon oxide, carbon dioxide, hydrocarbon, oxygen, etc.) is blown in from the lower tuyere or lower conduit. (2 or more types of gases mixed appropriately)
If molten steel is stirred weakly with a low amount of molten steel, the iron content (F'e) in the slag will increase and the yield will tend to be low.On the contrary, if the amount of stirring gas is increased and the molten steel is stirred strongly Although Fe in the slag decreases and P) also decreases, (Mn)
There is a tendency for the yield to decrease significantly. Therefore, in the conventional top-bottom blowing converter refining method, as shown in Fig. 1, oxygen is blown from the top and stirring gas is blown from the bottom (
During the blowing period (W)yc (hereinafter also referred to as bottom blowing), the amount of stirring gas is set low at the beginning of blowing, and at the end of blowing.
【は多くして脱
（Ｐ）を計ると共に〔Ｍ ｎ ）の歩留りを良くする方
法が採用されていた。
しかしながら、この従来法でも（Ｐ）、（Ｍ ｎ ）の
両者について満足する結果を得ることが出来なかった。
そこで、本発明者等は鋭意研究の結果、上多くする吹込
み（図においてパルス状脈動Ｐ１゜Ｐ２．、Ｐａとして
示す）を実施（本発明法）したところＣＰ）が低く（Ｍ
ｎ）が多い鋼を溶製するすることが出来ることを確認し
た
】・１図の従来方法と１１２図の本発明方法との溶製結
果の比較な次の１１１表に示す。
１１１表
賦香１が従来方法で、賦香２が本発明法であるが、本発
明法の成績が優れていることが判る。
さて前記脈動Ｐ１、Ｐ２、Ｐａは実際操業ではこのよう
に判然としたパルス状にはならず、急峻なウェーブ状と
なる。この点ＶＣついては後に詳述する。
次に本発明者等は転炉下部ＶＣ羽目＃１、＃２）２本を
適宜間隔をおいて設備し、１・３図に示した折線１で示
す攪拌ガス流量を２分して、間欠的吹込みの時期なずら
せ羽口＃１、＃２からそれぞれ折線２，３で示すように
吹込んだ、この溶製の結果を牙２表に示す。
牙２表
牙２表から明らかな如く、この方法が（Ｍ ｎ ）の歩
留りで特に良い成績が得られることが判る。
この理由は牙４図（ａ）、（ｂ） ｖｃ示ずように羽口
＃１゜＃２からの攪拌ガス吹込量の変化ｙｃより溶鋼流
４ａ、４ｂの方向が互ｆＣ反転されるため攪拌がムラの
ないものとなる結果と考えられる。尚、図において５は
溶鋼、６はスラグ、７は上吹酸素ランスを示す。
との牙４図（ａ）、（ｂ）の方法では、前述の（Ｐ）、
（Ｍｎ）ｒ（対する効果にとどまらず、スロッピングの
発生が非常に少なく、またスラグのフォーミングも抑制
できることが確認された。
さて本発明の攪拌ガス量の吹込みな間欠的に１．５倍量
以上変化させる点についてさらに詳述する゛。
１・５図の脈動Ｐ８は攪拌ガス流量における変化を模式
的に示した概念図で、Ｈが脈動Ｐ８の持続時間、しが最
大流量、看は定常流量な示す。定常流量とは当該転炉ｒ
Ｃおいてスロッピングやフォーミングなどで問題が生ず
ることなく精錬が良好に実行できると考えられる最低限
の流量で主として経験ｙｃよって求められる流量である
。
さて、実際の脈動はガス管路抵抗や弁の制御遅れなどに
よりす６図のＰ ９ （ｃ示すような急峻なウェーブと
なる。この場合、持続時間ｌ（はウェブＰ９の立上りか
ら立下りまでで、最大流量りは最高値なとる。
而して本発明においては、前記脈動Ｐ ９ ｖｃついて
、し≧１．５Ｊ、Ｈ＞１分なる条件な満足させるとき良
好な成績が得られた。
ｆ７図はＬ≧１．５１の要件を説明する実施例であり、
１７０ ｔｏｎ転炉において！−３０ＯＮｍ３／Ｈｒと
し、炭酸ガスを吹込み、Ｈを１分間として流量をＬ／１
３を１．０〜３．６まで変化させた例である。
才８図は牙７図の例において脱Ｐの指標である一６０ｇ
Ｋ ’ｐ ｆ縦軸に、Ｌ／−ｅｋ横軸ｙｃトッテｐｏ
ｇＫｐの変化を示したグラフで、図から明らかなようＶ
ＣＬ／−８が１．５で良好となり、１．８以上で効果が
飽和していることが判る。
たｒ（、Ｐ２０ａ：転炉スラグ中のＰ２Ｏ６の濃度（％
）〔Ｐ〕 ：溶鋼中のＰ濃度（％）
Ｉｌｌ 、 Ｆ ｅニスラグ中に含有される鉄分ゎ度（
％）牙９図は１・７図の例で、Ｈ＆ ０．１〜１ｏ分迄
変化させた場合の−（３ｏ ｇＫ’ ｐ ｆ示す。図か
ら１分以上で良好な結果が得られ２分で効果がｆｐｈし
、それ以上Ｈな大きくしてもあまり効果がないことが判
る。
次に脈動の回数であるが、１１１０図ｙｃ示す如く、Ｈ
を一定表して、ＩＨｘ１回（ａ）、％ ＨＸ ２回（ｂ
） Ｊ Ｈｘ ａ 回（ｃ ） （！： Ｌ テ実Ｗ
ｋ Ｌ ｋ、 ’ｊ％ 合、３１−１１図ｒ（示す通り
、脈動回数の多いほど良い成績が得られた。
しかしながら、実際操業では吹錬時間の制約があり、本
発明者等は脈動回数３〜４回で充分な効果が得られるこ
とを知った。さらに本発明者等は脈動の時期即ち攪拌ガ
ス流量の間欠的変化の時期はＳｉ吹終期、副原料投入終
期の２回に限定して実施すれば、目的の８０％以上を達
成することができると云う知見を得た。而して間欠的変
化を３回行う場合は吹錬期間のそれぞれ１／４ 、２／
２．３／４経過した時点な設定して実施すれば目的の８
５％以上の効果が期待できる。又間欠的変化の間隔りは
ｈ ＞ ｕであることが望ましい。
次（ｃＨ，Ｌ／、１３な種々に変化させた場合の効果比
較を才３表ＶＣ示す。
十３表から明らかなように本発明の方法な用いれば、（
Ｐ）ｋ下げ（Ｍ ｎ ）の歩留りな向上させることが出
来る。
而して本発明に用いられる攪拌ガスとしては、不活性ガ
ス又は炭陵ガスあるいは両者の混合ガスな用いて好適で
あった。また吹錬条件によっては不活性ガス又は炭酸ガ
スもしくはそれらの混合ガスのそれぞれに適宜量の酸素
を添加することニ者より好成績が得られた。本発明の目
的を逸脱しない範囲において他の攪拌ガスや添加剤を適
宜量添加することも許容される。
以上詳細に説明した通り、本発明は上底吹転炉ＶＣおい
て歩留りが良く高品質の鋼な精錬する実用上極めて簡便
でありながら効果の高い手段な提供するものである。
牙３表
■
＝A method has been adopted in which [ is increased to remove (P) and at the same time improve the yield of [M n ). However, even with this conventional method, satisfactory results could not be obtained for both (P) and (M n ). Therefore, as a result of intensive research, the present inventors conducted a method of the present invention that increased the amount of blowing (indicated as pulse-like pulsation P1゜P2., Pa in the figure), resulting in a low CP) (M
It has been confirmed that it is possible to melt steel with a large amount of n)] - A comparison of the melting results between the conventional method shown in Figure 1 and the method of the present invention shown in Figure 112 is shown in Table 111 below. 111 Table: Perfuming 1 is the conventional method, and Perfuming 2 is the method of the present invention, and it can be seen that the method of the present invention has superior results. Now, in actual operation, the pulsations P1, P2, and Pa do not have a clear pulse shape like this, but have a steep wave shape. This point regarding VC will be explained in detail later. Next, the inventors installed two VC panels #1 and #2 in the lower part of the converter at appropriate intervals, divided the stirring gas flow rate shown by broken line 1 shown in Figures 1 and 3 into two, and Table 2 shows the results of this melting, in which the timing of targeted blowing was staggered and blowing was performed from tuyeres #1 and #2 as shown by broken lines 2 and 3, respectively. As is clear from Table 2, this method provides particularly good results with respect to the yield of (M n ). The reason for this is that the directions of the molten steel flows 4a and 4b are reversed due to the change in the amount of stirring gas blown from the tuyeres #1 and #2, fC, as shown in Figures 4 (a) and (b). This is thought to be due to the fact that there is no unevenness. In the figure, 5 indicates molten steel, 6 indicates slag, and 7 indicates top-blown oxygen lance. In the method of Fig. 4 (a) and (b), the above-mentioned (P),
(Mn)r (Mn), it was confirmed that the occurrence of slopping was extremely small and slag forming could also be suppressed.Now, the amount of stirring gas of the present invention is intermittently 1.5 times as large as that of blowing. The point of changing the amount or more will be explained in more detail.The pulsation P8 in Figures 1 and 5 is a conceptual diagram schematically showing the change in the stirring gas flow rate, where H is the duration of the pulsation P8, H is the maximum flow rate, and Steady flow rate is indicated. Steady flow rate refers to the converter r
This is the minimum flow rate at which refining can be carried out satisfactorily without causing problems such as slopping or forming in C, and is determined primarily from experience yc. Now, the actual pulsation is caused by gas line resistance, valve control delay, etc., resulting in a steep wave as shown in P9 (c) in Figure 6. In this case, the duration l (is the period from the rise to the fall of web P9). Therefore, the maximum flow rate is the highest value.In the present invention, good results were obtained when the conditions of the pulsation P9vc were satisfied as follows: H≧1.5J and H>1 minute. The f7 diagram is an example explaining the requirement of L≧1.51,
In a 170 ton converter! -30ONm3/Hr, blow carbon dioxide gas, set H for 1 minute, flow rate L/1
This is an example in which 3 is changed from 1.0 to 3.6. The 8th figure is 160g which is an indicator of withdrawal from P in the example of the 7th figure
K'p f vertical axis, L/-ek horizontal axis yc tottepo
This is a graph showing changes in gKp, and as is clear from the figure, V
It can be seen that a CL/-8 of 1.5 is good, and a CL/-8 of 1.8 or more saturates the effect. tr(, P20a: Concentration of P2O6 in converter slag (%)
) [P]: P concentration in molten steel (%) Ill, Fe iron content contained in slag (
%) Fang Figure 9 is an example of Figures 1 and 7, and shows -(3o gK' p f) when H& is varied from 0.1 to 1o minutes.From the figure, good results are obtained in 1 minute or more, and 2 minutes. It can be seen that the effect is fph at fph, and increasing H further has no effect.Next is the number of pulsations, as shown in Figure 1110 yc.
IHx 1 time (a), %HX 2 times (b
) J Hx a times (c) (!: L Teri W
k L k, 'j% Figure 31-11 r (As shown, the higher the number of pulsations, the better the results were obtained. However, in actual operation, there is a restriction on the blowing time, so the inventors have decided to increase the number of pulsations. It was found that a sufficient effect could be obtained after 3 to 4 times.Furthermore, the inventors limited the period of pulsation, that is, the period of intermittent change in the stirring gas flow rate, to two times: at the end of Si blowing and at the end of auxiliary material input. We have obtained the knowledge that more than 80% of the objective can be achieved if the change is carried out in three times.If the intermittent change is carried out three times, it will take 1/4 and 2/2 of the blowing period, respectively.
2. If you set and implement after 3/4, you will achieve objective 8.
An effect of 5% or more can be expected. Further, it is desirable that the interval between intermittent changes satisfies h>u. Table 3 shows a comparison of the effects of various changes in (cH, L/, 13).As is clear from Table 13, if the method of the present invention is used, (
P) It is possible to improve the yield by lowering k (M n ). Therefore, as the stirring gas used in the present invention, an inert gas, a charcoal gas, or a mixture of the two gases were suitably used. Depending on the blowing conditions, better results were obtained by adding an appropriate amount of oxygen to each of inert gas, carbon dioxide gas, or a mixture thereof. It is also permissible to add appropriate amounts of other stirring gases and additives without departing from the purpose of the present invention. As explained in detail above, the present invention provides a practically simple and highly effective means for refining high-quality steel with good yield in a top-bottom blowing converter VC. Fang 3 table ■ =
牙１図は従来の吹錬における底吹撹拌ガス流量の変化を
示すグラフ、才２図は本発明ｙｃかへる底吹攪拌ガス流
量の変化を示すグラフ、、＋４−３図は本発明の実施例
ｙｃかへる異った底吹攪拌ガス流量の変化な示すグラフ
、、１′ｙ４図（ａ）、（ｂ）は本発明ｙｃかかる転炉
瘍鋼の攪拌状況な説明する概略図１才５図２オ６図は本
発明にかへる攪拌ガスの間欠的変化を脈動として示す模
式図、矛７図は本発明ｙｃかかる実施例での攪拌ガスの
間欠的変化の説明図。
オ８図、牙９図は脱Ｐの効率を説明するための夫々流量
と吹込時間との相関グラフ、牙１０図は本発明にかかる
攪拌ガスの間欠的吹込の態様を示すグラフ、牙１１図は
前記態様毎の脱Ｐ率の比較な示すグラフである。
Ｐ１〜Ｐ９：脈動、［（：脈動持続時間、Ｌ：最大流量
、看：定常流量。
代理人弁理士 秋 沢 政 光
外２名
活１図
’ｐｙｚ図
纂６図
蕊７図
異８図
第１θ圓
第１／図
Ｈ（旬Figure 1 is a graph showing changes in the flow rate of bottom-blown stirring gas in conventional blowing, Figure 2 is a graph showing changes in flow rate of bottom-blown stirring gas in the present invention. Figures (a) and (b) are schematic diagrams illustrating the stirring situation of the converter steel according to the present invention. Figures 5, 2, and 6 are schematic diagrams showing intermittent changes in the stirring gas according to the present invention as pulsations, and Figure 7 is an explanatory diagram of the intermittent changes in the stirring gas in this embodiment of the present invention. Fig. 8 and Fig. 9 are correlation graphs between the flow rate and the blowing time to explain the efficiency of P removal, Fig. 10 is a graph showing the mode of intermittent injection of stirring gas according to the present invention, and Fig. 11 is a graph showing the intermittent injection of stirring gas according to the present invention. is a graph showing a comparison of the P removal rates for each of the above embodiments. P1 to P9: Pulsation, [(: Pulsation duration, L: Maximum flow rate, K: Steady flow rate. Agent Patent Attorney Masa Akizawa Mitsugai 2 person life 1 Figure 'pyz collection 6 Figure 7 Figure 8) 1θ Circle 1/Figure H (Shun
Claims (1)
吹転炉精錬方法ＶＣおいて、前記攪拌ガス流量な吹錬の
初期から末期にかけて１回もしくは２回（２）攪拌ガス
が不活性ガスもしくは不活性ガスに酸素な添加したもの
である特許ｓｆｔ求の軛囲牙１項記載の方法。 （３）攪拌ガスが炭酸ガスもしくは炭酸ガスに酸素を添
加したものである特許請求の範囲牙１項記載の方法。 （４）攪拌ガスが不活性ガスと炭酸ガスの混合ガスもし
くはそれに酸素を添加したものである特許請求の範囲牙
１項記載の方法。 （５）攪拌ガスの間欠的変化を８ｉ吹終期および副原料
投入終期に限定実施する特許請求の範囲？１[Scope of Claims] (11) In the top-bottom blowing converter refining method VC in which oxygen is blown from the upper part and stirring gas is blown from the lower part, the stirring gas flow rate is set once or twice (2 times) from the beginning to the end of blowing. ) The method described in Paragraph 1 of the Patent SFT, where the stirring gas is an inert gas or an inert gas with oxygen added. (3) The stirring gas is carbon dioxide or a carbon dioxide with oxygen added. A method according to claim 1. (4) A method according to claim 1, wherein the stirring gas is a mixed gas of an inert gas and carbon dioxide, or a gas to which oxygen is added. (5) Scope of claim 1 in which intermittent changes in stirring gas are limited to the final stage of 8i blowing and the final stage of auxiliary material input?
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19803082A JPS5989705A (en) | 1982-11-11 | 1982-11-11 | Refining method with top and bottom blown converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19803082A JPS5989705A (en) | 1982-11-11 | 1982-11-11 | Refining method with top and bottom blown converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5989705A true JPS5989705A (en) | 1984-05-24 |
| JPS6232244B2 JPS6232244B2 (en) | 1987-07-14 |
Family
ID=16384353
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19803082A Granted JPS5989705A (en) | 1982-11-11 | 1982-11-11 | Refining method with top and bottom blown converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5989705A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009293096A (en) * | 2008-06-06 | 2009-12-17 | Kobe Steel Ltd | Method for injecting bottom-blowing agitation gas in melting furnace |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55158208A (en) * | 1979-05-24 | 1980-12-09 | Sumitomo Metal Ind Ltd | Refining method of steel |
-
1982
- 1982-11-11 JP JP19803082A patent/JPS5989705A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55158208A (en) * | 1979-05-24 | 1980-12-09 | Sumitomo Metal Ind Ltd | Refining method of steel |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009293096A (en) * | 2008-06-06 | 2009-12-17 | Kobe Steel Ltd | Method for injecting bottom-blowing agitation gas in melting furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6232244B2 (en) | 1987-07-14 |
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