JPH0433843B2 - - Google Patents
Info
- Publication number
- JPH0433843B2 JPH0433843B2 JP7738888A JP7738888A JPH0433843B2 JP H0433843 B2 JPH0433843 B2 JP H0433843B2 JP 7738888 A JP7738888 A JP 7738888A JP 7738888 A JP7738888 A JP 7738888A JP H0433843 B2 JPH0433843 B2 JP H0433843B2
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- converter
- steel
- flow velocity
- linear flow
- 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
Links
Landscapes
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は上底吹き転炉、底吹き転炉によりステ
ンレス鋼を溶製精錬する方法に関し、詳しくは鋼
中窒素の低減化を転炉の炉口開口面積を変えるこ
とで図るものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for melting and refining stainless steel using a top-bottom blowing converter or a bottom-blowing converter. This is achieved by changing the area of the furnace opening.
一般に底吹き転炉や上底吹き転炉においては、
気泡が溶鉄中を上昇する過程でのフラツシング効
果により、脱窒速度が上吹転炉より速い。しかし
近年の極底窒素ステンレス鋼の精錬の場合、上記
フラツシング効果のみでは脱窒効果が不充分であ
る。
Generally, in bottom blowing converter and top and bottom blowing converter,
The denitrification rate is faster than in a top-blown converter due to the flushing effect during the process in which bubbles rise through the molten iron. However, in the case of refining of extremely low nitrogen stainless steel in recent years, the denitrification effect is insufficient with the flushing effect alone.
そこで本発明の目的は、鋼中窒素をコスト的有
利に低減させる方法を提供することにある。 Therefore, an object of the present invention is to provide a cost-effective method of reducing nitrogen in steel.
上記課題を解決するための本発明は、上底吹き
転炉、底吹き転炉におけるステンレス溶製精錬に
おいて、転炉の炉口での排ガス線流速が16Nｍ／
min以上である炉口開口面積を有する転炉を用い
ることを特徴とするものである。
In order to solve the above problems, the present invention is applicable to stainless steel melting and refining in a top-bottom blowing converter or a bottom-blowing converter, in which the exhaust gas linear flow velocity at the furnace mouth of the converter is 16 Nm/
This method is characterized by using a converter having a furnace opening area of min or more.
本発明では、炉口断面積を減少させ、排ガスの
炉口線流速を上昇させるものであるから、鋼浴表
面に空気が侵入せず、したがつて炉内のPN2（窒
素分圧）を低下させることができるので、鋼中の
窒素量を低減化できる。
In the present invention, since the cross-sectional area of the furnace mouth is reduced and the linear flow velocity of the exhaust gas at the furnace mouth is increased, air does not enter the steel bath surface, and therefore the PN 2 (nitrogen partial pressure) in the furnace is reduced. Therefore, the amount of nitrogen in the steel can be reduced.
以下本発明をさらに具体的に説明する。まず本
発明完成に至る過程について説明すると、一般に
ステンレス鋼精錬においては、吸Ｎ反応（窒素を
吸収する反応）は主に鋼浴表面で起こり、脱Ｎ反
応は主に気泡表面でおこる。そこで全体としての
吸Ｎ速度は近似的に(1)式で示すことができる。
The present invention will be explained in more detail below. First, the process leading to the completion of the present invention will be described. In general, in stainless steel refining, N absorption reactions (reactions that absorb nitrogen) mainly occur on the surface of the steel bath, and N removal reactions mainly occur on the surfaces of bubbles. Therefore, the overall N absorption rate can be approximately expressed by equation (1).
dN／dt＝k′（〔Ｎ〕e−〔Ｎ〕）
−Ａ／Ｖｋ〔Ｎ〕2 ……(1)
ここで〔Ｎ〕：Ｎの濃度
〔Ｎ〕e：Ｎの平衡濃度
k′：物質移動容量係数
ｋ：反応速度定数
Ａ：気泡表面積
Ｖ：鋼浴体積
上記式(1)より、鋼中Ｎを低下させるには、〔Ｎ〕
eを低下させ、したがつて炉内PN2を低下させれ
ばよいことがわかる。 dN/dt=k' ([N] e - [N]) -A/Vk[N] 2 ...(1) where [N]: Concentration of N [N] e : Equilibrium concentration of N k': Mass transfer capacity coefficient k: Reaction rate constant A: Bubble surface area V: Steel bath volume From the above formula (1), in order to reduce N in steel, [N]
It can be seen that it is sufficient to reduce e and therefore the in-furnace PN 2 .
ところで炉内PN2を低下させるには、侵入空気
量を減少させる必要がある。この侵入空気量は炉
口における排ガスの線流速（以下「炉口線流速」
という）との相関が大きく、一般的に第３図のよ
うな傾向を示す。第３図から、炉口線流速が増加
するにともない、侵入空気良が減少していること
がわかる。しかも炉口線流速を16Nｍ／min以上
とすれば、侵入空気量は約20Nm33／hrに低減で
きる。 By the way, in order to lower the PN 2 in the furnace, it is necessary to reduce the amount of intruding air. This amount of incoming air is the linear flow velocity of exhaust gas at the furnace mouth (hereinafter referred to as the "furnace linear flow velocity").
), and generally shows the tendency shown in Figure 3. From FIG. 3, it can be seen that as the linear flow velocity at the furnace mouth increases, the amount of air entering the furnace decreases. Moreover, if the linear flow rate at the furnace mouth is set to 16 Nm/min or more, the amount of intruding air can be reduced to about 20 Nm 33 /hr.
また、前述の如く、侵入空気量が増大すれば炉
内PN2が増加することが考えられ、この点を確認
するため、炉内PN2と炉口線流速との関係を調べ
たところ、第４図の結果を得た。この図より、や
はり炉口線流速の増加に伴い、炉内PN2が低下す
るとがわかり、特に炉口線流速を16Nｍ／min以
上にすれば、炉内PN23.0×10-3atm程度のレベル
を十分に確保できる。 In addition, as mentioned above, it is thought that if the amount of incoming air increases, the PN 2 in the furnace increases.To confirm this point, we investigated the relationship between the PN 2 in the furnace and the linear flow velocity at the furnace mouth. The results shown in Figure 4 were obtained. From this figure, it can be seen that the in-furnace PN 2 decreases with an increase in the linear flow velocity at the furnace throat. In particular, if the linear flow velocity at the furnace throat is increased to 16 Nm/min or more, the in-furnace PN 2 decreases to about 3.0×10 -3 atm. A sufficient level can be ensured.
次に第５図には、炉内PN2と鋼中Ｎの関係の調
査結果を示すが、この図より炉内PN2を低下させ
れば鋼中Ｎを低減できることが確認できる。 Next, FIG. 5 shows the results of an investigation into the relationship between PN 2 in the furnace and N in steel, and it can be confirmed from this figure that N in steel can be reduced by lowering PN 2 in the furnace.
さて、以上の結果より、鋼中Ｎを低下させるに
は、炉内PN2を低下させればよく、この炉内PN2
を低下させるには炉口線流速を16Nｍ／min以上
まで上昇させればよいことが判る。ところで、炉
口線流速を上昇させるには、底吹きガス（Ar）
流量を増加させる方法、炉口断面積を減少させ
る方法の２方法が考えられる。上記の方法で
は、高価なArガス使用量が増加し、コスト上昇
につながるため、本発明ではの方法を採用する
ものである。 Now, from the above results, in order to lower the N in steel, it is sufficient to lower the PN 2 in the furnace, and this PN 2 in the furnace
It can be seen that in order to reduce this, it is sufficient to increase the linear flow velocity at the furnace mouth to 16 Nm/min or more. By the way, in order to increase the linear flow velocity at the furnace mouth, bottom blowing gas (Ar)
There are two possible methods: increasing the flow rate and decreasing the cross-sectional area of the furnace mouth. In the above method, the amount of expensive Ar gas used increases, leading to an increase in cost, so the method of the present invention is adopted.
第１図は本発明に係る底吹き転炉を示すたもの
で、図中、１は出鋼孔、２，２はトラニオン軸、
３は炉口部を示している。 FIG. 1 shows a bottom blowing converter according to the present invention, in which 1 is a tapping hole, 2 is a trunnion shaft,
3 indicates the furnace mouth.
前述のように鋼中Ｎを減少させるためには、こ
の炉口部３の断面積をできるだけ減少させる必要
がある。しかし他方において、炉口には、溶鋼情
報を得るためメインランス４、サブランス５を挿
入するため、また副原料投入のため、ある程度の
開口面積が必要である。そこで本発明では、操業
上の制約とならない範囲で炉口開口を狭めるた
め、円形開口に対して切欠円状の炉口開口面積調
整蓋６，６を設けるものである。この蓋６は耐火
物によつて形成される。７は底吹口である。 As mentioned above, in order to reduce the N content in the steel, it is necessary to reduce the cross-sectional area of the furnace mouth 3 as much as possible. However, on the other hand, the furnace mouth requires a certain amount of opening area in order to insert the main lance 4 and sub-lance 5 to obtain information on molten steel, and to input auxiliary materials. Therefore, in the present invention, in order to narrow the furnace opening within a range that does not cause operational constraints, the furnace opening area adjustment lids 6, 6 having circular notches are provided for the circular opening. This lid 6 is made of refractory material. 7 is the bottom blowing mouth.
第１図に示す炉口断面積を減少させた転炉を用
いると、第２図に示されているように、炉口線流
速が22Nｍ／minに上昇し、鋼中Ｎが102ppmか
ら60ppmに低下した。
When a converter with a reduced cross-sectional area at the furnace mouth shown in Figure 1 is used, the linear flow velocity at the furnace mouth increases to 22 Nm/min, and the N content in the steel decreases from 102 ppm to 60 ppm, as shown in Figure 2. decreased.
なお、従来の炉口線速度は、転炉の大きさにも
よるが、一般に、12〜14Nｍ／minである。した
がつて従来法では本発明のような効果は期待でき
ない。 In addition, the conventional furnace mouth linear velocity is generally 12 to 14 Nm/min, although it depends on the size of the converter. Therefore, the effects of the present invention cannot be expected with the conventional method.
以上の通り、本発明によれば、鋼中Ｎを転炉の
炉口のみ改造によつてコスト的有利に低減させる
ことができる。
As described above, according to the present invention, N in steel can be reduced cost-effectively by modifying only the furnace mouth of the converter.
第１図は本発明に係る転炉を示したもので、ａ
は縦断面図、ｂは平面図、第２図は本発明による
鋼中Ｎの低減効果を示す図、第３図は侵入空気量
と炉口線流速との関係図、第４図は炉内PN2と炉
口線流速との関係図、第５図は鋼中Ｎと炉内PN2
との関係図である。
１……出鋼孔、２……トラニオン軸、３……炉
口部、４……メインランス、５……サブランス、
６，６……炉口開口面積調整蓋。
FIG. 1 shows a converter according to the present invention, a
is a vertical cross-sectional view, b is a plan view, Fig. 2 is a diagram showing the effect of reducing N in steel according to the present invention, Fig. 3 is a diagram showing the relationship between the amount of incoming air and the linear flow velocity at the furnace mouth, and Fig. 4 is a diagram showing the inside of the furnace. Figure 5 shows the relationship between PN 2 and linear flow velocity at the furnace mouth .
This is a relationship diagram. 1...Tapping hole, 2...Trunion shaft, 3...Furnace mouth, 4...Main lance, 5...Sub-lance,
6, 6... Furnace opening area adjustment lid.
Claims (1)
ス溶製精錬において、転炉の炉口での排ガス線流
速が16Nｍ／min以上である炉口開口面積を有す
る転炉を用いることを特徴とするステンレス鋼の
溶製精錬方法。1. Stainless steel smelting and refining in a top-bottom blowing converter or a bottom-blowing converter is characterized by using a converter having a furnace opening area such that the exhaust gas linear flow velocity at the furnace mouth of the converter is 16 Nm/min or more. Smelting and refining method of stainless steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7738888A JPH01247525A (en) | 1988-03-30 | 1988-03-30 | Method for melting and refining stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7738888A JPH01247525A (en) | 1988-03-30 | 1988-03-30 | Method for melting and refining stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01247525A JPH01247525A (en) | 1989-10-03 |
| JPH0433843B2 true JPH0433843B2 (en) | 1992-06-04 |
Family
ID=13632509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7738888A Granted JPH01247525A (en) | 1988-03-30 | 1988-03-30 | Method for melting and refining stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01247525A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4761938B2 (en) * | 2005-08-17 | 2011-08-31 | 株式会社神戸製鋼所 | Blowing method for converter |
-
1988
- 1988-03-30 JP JP7738888A patent/JPH01247525A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01247525A (en) | 1989-10-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3565605A (en) | Process for the continuous refining of metals | |
| GB2099021A (en) | Preventing foaming when refining pig iron by top-slawing agent and device for carrying out the process | |
| JPH0433843B2 (en) | ||
| JPH0328484B2 (en) | ||
| US3930843A (en) | Method for increasing metallic yield in bottom blown processes | |
| JP2767674B2 (en) | Refining method of high purity stainless steel | |
| JP3118606B2 (en) | Manufacturing method of ultra-low carbon steel | |
| JPS62235415A (en) | Extremely small-sized refining container | |
| KR100225249B1 (en) | Remaining slag control method of of slopping control | |
| JPS58167707A (en) | Method of smelting high-carbon steel by top and bottom-blown converter | |
| JPH05311231A (en) | Refining method of high-purity steel using reflux type vacuum degasser | |
| JP2819424B2 (en) | Manufacturing method of ultra-low carbon steel | |
| JPS6149758A (en) | Molten steel sealing method in tandish | |
| JP3225747B2 (en) | Vacuum degassing of molten steel | |
| JPS57158316A (en) | Production of al-containing steel | |
| JP3025042B2 (en) | Manufacturing method of ultra-low carbon steel | |
| JP3282487B2 (en) | Manufacturing method of enamel steel | |
| JP2940358B2 (en) | Melting method for clean steel | |
| RU1836442C (en) | Chamber unit for melted metal refining | |
| JPS5822319A (en) | Manufacture for steel having super low hydrogen and super low sulfur content | |
| JPH0535842U (en) | Converter type metallurgical reactor | |
| JPH0433847B2 (en) | ||
| JPS59166617A (en) | Method for refining chromium-containing molten steel | |
| JPH03153816A (en) | Smelting method for high purity steel | |
| DE3560187D1 (en) | Process for the production of ferromanganese refined by metallothermic reactions in the ladle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |