JPH01301814A - Refining method of high-cleanliness steel - Google Patents
Refining method of high-cleanliness steelInfo
- Publication number
- JPH01301814A JPH01301814A JP13008588A JP13008588A JPH01301814A JP H01301814 A JPH01301814 A JP H01301814A JP 13008588 A JP13008588 A JP 13008588A JP 13008588 A JP13008588 A JP 13008588A JP H01301814 A JPH01301814 A JP H01301814A
- Authority
- JP
- Japan
- Prior art keywords
- slag
- molten steel
- ladle
- added
- tapping
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 61
- 239000010959 steel Substances 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims description 6
- 238000007670 refining Methods 0.000 title claims description 5
- 239000002893 slag Substances 0.000 claims abstract description 60
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 44
- 238000010079 rubber tapping Methods 0.000 claims abstract description 16
- 238000006722 reduction reaction Methods 0.000 claims abstract description 12
- 230000009257 reactivity Effects 0.000 claims abstract description 6
- 238000009849 vacuum degassing Methods 0.000 claims abstract description 6
- 230000005587 bubbling Effects 0.000 claims description 12
- 238000013019 agitation Methods 0.000 claims 1
- 238000007664 blowing Methods 0.000 abstract description 7
- 238000003756 stirring Methods 0.000 abstract description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 238000007872 degassing Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000003068 static effect Effects 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002407 reforming Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 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
- 238000010587 phase diagram Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明はスラグ改質による高清浄度鋼の精錬方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for refining high-cleanliness steel by slag reforming.
〈従来の技術〉
転炉からの出鋼時に取鍋へ流出するスラグには１０〜２
０％の高濃度のＴｌ”ｅ（酸化鉄）が含まれており、何
も処理を施さない場合には、このスラグにより溶鋼中の
ＡＩが酸化され、溶鋼中の非金属介在物であるＭ、０．
が増大する。これを防止するために、特開昭５３−１０
６３１７号公報に開示されている技術では、取鍋自溶鋼
表面に低融点のＣａＯ−３ｉｆｔ−へ！、０．系合成ス
ラグを形成しＡｒ Ｑ拌を行うことにより酸化鉄の還元
を促進している。<Conventional technology> The slag that flows into the ladle during tapping from the converter contains 10 to 2
Contains a high concentration of 0% Tl"e (iron oxide), and if no treatment is performed, this slag will oxidize AI in the molten steel, and M ,0.
increases. In order to prevent this, JP-A-53-10
In the technique disclosed in Publication No. 6317, low melting point CaO-3ift- is deposited on the surface of the self-melting steel in the ladle! ,0. The reduction of iron oxide is promoted by forming a system synthesis slag and performing Ar Q stirring.
〈発明が解決しようとする課題〉
しかるに上記の従来の技術では低融点のスラグが形成さ
れるため溶鋼との反応性が高く、スラグ改質後にも若干
残存する酸化鉄及びＳｉｎｇの影響により溶鋼中のＡＩ
酸化が進行するためＡｌｔｏｓの低減が十分達成されな
いという問題点があった。<Problems to be Solved by the Invention> However, in the above-mentioned conventional technology, slag with a low melting point is formed, which is highly reactive with molten steel, and even after slag modification, iron oxide and Sing, which remain slightly, cause slag to form in molten steel. AI
There is a problem in that Altos cannot be sufficiently reduced because oxidation progresses.
本発明は上記従来の問題点を解消し、スラグ改質後にも
なお生じる溶鋼中のＮとスラグ中の酸化鉄や５ｉ０ｚと
の反応によるＡｌｔｏｓの生成を抑制することができる
高清浄度鋼の精錬方法を提供することを目的とするもの
である。The present invention solves the above-mentioned conventional problems and is capable of refining high-cleanliness steel that can suppress the formation of Altos due to the reaction between N in molten steel and iron oxide and 5iOz in slag, which are still generated even after slag modification. The purpose is to provide a method.
〈課題を解決するための手段〉
上記目的を達成するための本発明の高清浄度鋼の精錬方
法は、転炉で溶製した溶鋼の出鋼中に、取鍋内にＣａＯ
を添加し、さらに出鋼末期および／または出鋼後に取鍋
内のスラグ上にＡｔを添加する一方、溶鋼中に静ガスを
吹込んでバブリング攪拌することによって転炉から流出
したスラグの流動性をよくすると共に酸化鉄の還元反応
を促進して還元処理し、その後、取鍋内の溶鋼を真空脱
ガス処理する際に、真空脱ガス槽内にｎｇｏを添加し、
スラグと溶鋼との界面における反応性を抑制することを
特徴とするものである。<Means for Solving the Problems> In order to achieve the above object, the high-cleanliness steel refining method of the present invention includes CaO in the ladle during tapping of molten steel produced in a converter.
Furthermore, At is added to the slag in the ladle at the end of tapping and/or after tapping, while the fluidity of the slag flowing out from the converter is improved by blowing static gas into the molten steel and stirring it by bubbling. At the same time, when the reduction reaction of iron oxide is promoted and the reduction treatment is performed, NGO is added to the vacuum degassing tank when the molten steel in the ladle is vacuum degassed.
It is characterized by suppressing reactivity at the interface between slag and molten steel.
〈作 用〉
転炉からの出鋼時に取消へ流出するスラグ中には１０〜
２０％のＴｉｅ（酸化鉄）が含まれており、流出したま
まの状態ではスラグ中の酸化鉄により溶鋼中のＭが酸化
され、非金属介在物であるＡｌｔ’：ｈが増大する。そ
れを防止するためにスラグ中に八ｔを添加し、溶鋼中に
Ａｒガスを吹込んでバブリング攪拌することによってス
ラグの酸化鉄を還元するのが有効である。＾ｒガス吹込
み手段としては溶鋼中に吹込ランスを浸漬して吹込むか
あるいは取鍋底に設けたポーラスプラグから吹込むなど
の常用手段を使用する。<Function> The slag that flows out from the converter when steel is tapped contains 10~
Contains 20% Tie (iron oxide), and if the slag continues to flow out, iron oxide in the slag oxidizes M in the molten steel, increasing Alt':h, which is a nonmetallic inclusion. In order to prevent this, it is effective to reduce the iron oxide in the slag by adding 8t to the slag and blowing Ar gas into the molten steel for bubbling stirring. ^r As a gas blowing means, a conventional means such as dipping a blowing lance into the molten steel or blowing through a porous plug provided at the bottom of the ladle is used.
第１図に静ガスバブリング処理を１０分間行った後のス
ラグ液相線温度とスラグ中の酸化鉄還元率との関係を示
しているが、同第１図から明らかなようにスラグ液相線
温度が低いほどスラグ中のＴ・ＦｅＣＭ化鉄）は低くな
る。ところで液相線温度は周知のＣａＯ／ＶＶｔ０３−
５ｉｎ系状態図（図示略）から重量比でＣａＯ： ｆｉ
ＪｚＯｓ −１： １のときに液相線温度が最も低くな
る。Figure 1 shows the relationship between the slag liquidus temperature and the iron oxide reduction rate in the slag after 10 minutes of static gas bubbling treatment. The lower the temperature, the lower the amount of T.FeCM (iron oxide) in the slag. By the way, the liquidus temperature is the well-known CaO/VVt03-
From the 5in system phase diagram (not shown), the weight ratio is CaO: fi
JzOs −1: When 1, the liquidus temperature is the lowest.
そこで本発明では転炉の出鋼中に取鍋内にＣａＯを添加
し、転炉から流出するスラグを改質しスラグ組成をＣａ
Ｏ： ＮｚＯｓ −１ｉ １に近づけることによって低
融点のＣａ０−ｋｌｚＣｈ系スラグとすることによって
スラグの流動性をよくしてＭによる酸化鉄の還元反応を
速くするのである。そのためにはＭと酸化鉄との反応に
より生じるＭ２Ｏ３とほぼ同量のＣａＯを添加すること
が肝要となる。Therefore, in the present invention, CaO is added into the ladle during tapping of the converter, and the slag flowing out from the converter is modified to change the slag composition to Ca.
By bringing O: NzOs -1i close to 1, a Ca0-klzCh-based slag with a low melting point is obtained, which improves the fluidity of the slag and speeds up the reduction reaction of iron oxide by M. For this purpose, it is important to add approximately the same amount of CaO as M2O3 produced by the reaction between M and iron oxide.
このようにすることによって取鍋内スラグ中の酸化鉄濃
度を低くすることができるが酸化鉄を零にまで低くする
ことができず残留酸化鉄を若干含むスラグが溶鋼の表面
上に存在するので第２図の実線で示すように鋳造までの
間に低融点で反応性の高いスラグ中の残留酸化鉄と溶鋼
中のＭとの反応によりＭ、０．が生成し、溶鋼の清浄化
が妨げられる。By doing this, the iron oxide concentration in the slag in the ladle can be lowered, but the iron oxide concentration cannot be reduced to zero, and slag containing some residual iron oxide remains on the surface of the molten steel. As shown by the solid line in FIG. 2, the residual iron oxide in the slag, which has a low melting point and high reactivity, reacts with the M in the molten steel until casting, resulting in M, 0. is generated, which hinders the cleaning of molten steel.
上記のようなスラグ改質後のＡＩよ０．生成を防止する
にはスラグの流動性を無（し溶鋼との反応速度を極力遅
くすることが有効である。The AI after slag modification as described above is 0. To prevent slag formation, it is effective to eliminate the fluidity of slag and to slow down the reaction rate with molten steel as much as possible.
そこで本発明ではその後の取鍋内溶鋼の真空脱ガス処理
に際し、例えばＲＨ肌脱ガス時ＲＨ脱ガス槽内にＭｇＯ
を添加することによりスラグと溶鋼の界面での反応を抑
制するものである。Therefore, in the present invention, during the subsequent vacuum degassing treatment of molten steel in the ladle, for example, MgO is added to the RH degassing tank during RH skin degassing.
By adding , the reaction at the interface between slag and molten steel is suppressed.
ＭｇＯをＲＨ脱ガス槽に添加するのは、添加した）１ｇ
ｏが下降管から環流する溶鋼と共に取鍋内に環流したの
ち浮上し、溶鋼との界面のスラグを改質して流動性の悪
い固化状のスラグを生成させ溶鋼とスラグの界面での反
応性を低下させることによって溶鋼中のＭの酸化を防止
し、溶鋼中のＭ、０゜系非金属介在物を低減するからで
ある。When adding MgO to the RH degassing tank, 1 g of MgO is added.
The o flows into the ladle together with the molten steel flowing back from the downcomer pipe, and then floats to the surface, reforming the slag at the interface with the molten steel, producing solidified slag with poor fluidity, and increasing the reactivity at the interface between the molten steel and slag. This is because by lowering the molten steel, oxidation of M in the molten steel is prevented, and M, 0° series nonmetallic inclusions in the molten steel are reduced.
第２図にＡｒバブリング処理後と鋳込直前の連鋳タンデ
イツシュ溶鋼間の鋼中Ｎ低下量とＲＨ処理後スラグ中の
Ｔｌ’ｅとの関係をＲＨ脱ガス槽にＭｇＯを添加した場
合と無添加の場合とを比較して示している。同第２図か
らＲＨ脱ガス槽にＭｇＯを添加する場合には無添加の場
合と比較して鋼中のＭ低下の抑制効果が顕著であること
が分かる。Figure 2 shows the relationship between the amount of N reduction in the steel after Ar bubbling treatment and the continuous casting tandem molten steel immediately before casting, and the Tl'e in the slag after RH treatment, when MgO is added to the RH degassing tank and when MgO is added to the RH degassing tank. A comparison with the case of addition is shown. From FIG. 2, it can be seen that when MgO is added to the RH degassing tank, the effect of suppressing the decrease in M in the steel is more significant than when no MgO is added.
〈実施例〉 以下、本発明の実施例を詳細に説明する。<Example> Examples of the present invention will be described in detail below.
２３０を転炉から溶鋼を出鋼中に取鍋内溶鋼にＣａＯを
５００ｋｇ、脱酸のためのＡｌを２５０ｋｇを添加し、
出鋼後に更にスラグ改質のための八ｌを１００ｋｇスラ
グ上に添加した。この状態で吹込ランスから溶鋼中に静
ガスを吹込んでバブリング攪拌し、スラグ中の酸化鉄を
還元した。さらに取鍋内の溶鋼をＲＨ脱ガス処理する際
に、その初期にＲＨ脱ガス槽内にＭｇＯを２００ｋｇ添
加し、ＲＨ脱ガス処理を２０分間施した。While tapping molten steel from the converter, 500 kg of CaO and 250 kg of Al for deoxidation were added to the molten steel in the ladle.
After tapping, 8 liters of slag was further added to the 100 kg of slag for slag modification. In this state, static gas was blown into the molten steel from the blowing lance to stir the molten steel by bubbling, thereby reducing the iron oxide in the slag. Furthermore, when performing RH degassing treatment on the molten steel in the ladle, 200 kg of MgO was added into the RH degassing tank at the beginning, and RH degassing treatment was performed for 20 minutes.
出鋼時の炉内溶鋼成分、計バブリング処理後の溶鋼成分
、ＲＨ処理後の鋳込直前の溶鋼成分を第１表に、また出
鋼時の炉内スラグ成分と静バブリング処理後のスラグ成
分を第２表に示している。Table 1 shows the molten steel composition in the furnace during tapping, the molten steel composition after total bubbling treatment, the molten steel composition immediately before pouring after RH treatment, and the slag composition in the furnace during tapping and the slag composition after static bubbling treatment. are shown in Table 2.
ＣａＯおよびＡｌを添加した上でＡｒバブリングするこ
とによりスラグ中の酸化鉄を表す（Ｔ４ｅ）４度は１０
％から１．５％に低減している。ざらにＲＨ処理時にＭ
ｇＯを添加し、溶鋼とスラグ間の反応を抑制したため、
計バブリング後から鋳込直前の溶鋼成分中のＡＩ低下量
はわずか０．００３％にすぎず八ｌ、０．の生成が効果
的に抑制されたことを示している。By adding CaO and Al and then Ar bubbling, the iron oxide in the slag is expressed (T4e) 4 degrees is 10
% to 1.5%. M during rough RH treatment
By adding gO to suppress the reaction between molten steel and slag,
The amount of decrease in AI in the molten steel components from after bubbling to just before pouring is only 0.003%, which is 8l, 0. This shows that the production of was effectively suppressed.
これに対してＣａＯおよびＭ添加によるスラグ改質は前
記実施例と同様に行ったがＲＨ脱ガス処理時にＭｇＯを
添加しなかった比較例では、スラグ中のＴ−Ｆｅは上記
実施例と同程度に低下しているが、静バブリング後から
鋳込直前までの間の鋼中のＡＩ低下量が０．０１０％と
大きく、この間のへｌχ０３生成量が多く、溶鋼の清浄
化を悪化させていることを示している。鋼中の酸素も実
施例の２２ｐｐｆｉに対して３２ｐｐ＋ｗと１０ｐｐ曽
高くなっている。On the other hand, in a comparative example in which slag modification by addition of CaO and M was carried out in the same manner as in the above example, but MgO was not added during RH degassing treatment, T-Fe in the slag was at the same level as in the above example. However, the amount of AI reduction in the steel from after static bubbling to just before casting is as large as 0.010%, and the amount of lχ03 produced during this period is large, worsening the cleaning of molten steel. It is shown that. Oxygen in the steel is also 32pp+w, which is 10pp higher than the 22ppfi of the example.
〈発明の効果〉
以上述べたように本発明ではまずＣａＯを添加して流動
性のよいスラグを形成して添加したＮによる酸化鉄の還
元を促進し、次いでＭｇＯによってスラグを固化して鋼
中のＭ酸化を防止するのでＮ８０．の少ない清浄鋼を容
易に得ることができる。<Effects of the Invention> As described above, in the present invention, CaO is first added to form a highly fluid slag to promote the reduction of iron oxide by the added N, and then the slag is solidified by MgO to form a slag with good fluidity. Since it prevents M oxidation of N80. It is possible to easily obtain clean steel with low
第１図はスラグ液相線温度（°Ｃ）とスラグのＦｅＯ還
元率（％）との関係を示すグラフ、第２図はＡｒバブリ
ング後と鋳込直前間の鋼中のＭ低下Ｎ（％）とＲＨ処理
後のスラグＴ−Ｐｅ （％）との関係をｑｇｏを添加し
た場合と無添加の場合とを比較して示したグラフである
。
特許出願人 川崎製鉄株式会社
第 １ 図
ＲＨ処理後のスラグ中の（％Ｔ４ｅ）Figure 1 is a graph showing the relationship between slag liquidus temperature (°C) and slag FeO reduction rate (%), Figure 2 is a graph showing the decrease in M (N) in steel after Ar bubbling and immediately before casting (%). ) and the slag T-Pe (%) after RH treatment in the case where qgo is added and the case where it is not added. Patent applicant Kawasaki Steel Corporation Figure 1 (%T4e) in slag after RH treatment
Claims (1)
し、さらに出鋼末期および／または出鋼後に取鍋内のス
ラグ上にＡｌを添加する一方、溶鋼中にＡｒガスを吹込
んでバブリング攪拌することによって転炉から流出した
スラグの流動性をよくすると共に酸化鉄の還元反応を促
進して還元処理し、その後、取鍋内の溶鋼を真空脱ガス
処理する際に、真空脱ガス槽内にＭｇＯを添加し、スラ
グと溶鋼との界面における反応性を抑制することを特徴
とする高清浄度鋼の精錬方法。During tapping of molten steel produced in a converter, CaO is added to the ladle, and Al is added to the slag in the ladle at the end of tapping and/or after tapping, while Ar gas is added to the molten steel. By injecting and bubbling agitation, the fluidity of the slag flowing out from the converter is improved, and the reduction reaction of iron oxide is promoted. Afterwards, when the molten steel in the ladle is vacuum degassed, A highly clean steel refining method characterized by adding MgO in a vacuum degassing tank to suppress reactivity at the interface between slag and molten steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13008588A JPH01301814A (en) | 1988-05-30 | 1988-05-30 | Refining method of high-cleanliness steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13008588A JPH01301814A (en) | 1988-05-30 | 1988-05-30 | Refining method of high-cleanliness steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01301814A true JPH01301814A (en) | 1989-12-06 |
Family
ID=15025616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13008588A Pending JPH01301814A (en) | 1988-05-30 | 1988-05-30 | Refining method of high-cleanliness steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01301814A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03183722A (en) * | 1989-12-12 | 1991-08-09 | Nippon Steel Corp | Production of high cleanliness steel |
| JPH05222428A (en) * | 1992-02-06 | 1993-08-31 | Nippon Steel Corp | Method for reforming slag |
| EP0548868A3 (en) * | 1991-12-24 | 1994-09-07 | Kawasaki Steel Co | Method of refining of high purity steel |
| JP2003041315A (en) * | 2001-07-31 | 2003-02-13 | Nkk Corp | Manufacturing method of high clean steel |
| JP2008063647A (en) * | 2006-09-11 | 2008-03-21 | Jfe Steel Kk | Desulfurization method for molten steel |
| JP2008240136A (en) * | 2007-03-29 | 2008-10-09 | Jfe Steel Kk | Method of melting high cleanliness steel |
| JP2015183259A (en) * | 2014-03-25 | 2015-10-22 | 新日鐵住金株式会社 | Method for melting high cleanliness steel |
| CN108823357A (en) * | 2018-07-09 | 2018-11-16 | 上海宽量节能投资有限公司 | A kind of degassing system and its degassing method based on flexible mechanical vacuum pump group |
-
1988
- 1988-05-30 JP JP13008588A patent/JPH01301814A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03183722A (en) * | 1989-12-12 | 1991-08-09 | Nippon Steel Corp | Production of high cleanliness steel |
| EP0548868A3 (en) * | 1991-12-24 | 1994-09-07 | Kawasaki Steel Co | Method of refining of high purity steel |
| JPH05222428A (en) * | 1992-02-06 | 1993-08-31 | Nippon Steel Corp | Method for reforming slag |
| JP2003041315A (en) * | 2001-07-31 | 2003-02-13 | Nkk Corp | Manufacturing method of high clean steel |
| JP2008063647A (en) * | 2006-09-11 | 2008-03-21 | Jfe Steel Kk | Desulfurization method for molten steel |
| JP2008240136A (en) * | 2007-03-29 | 2008-10-09 | Jfe Steel Kk | Method of melting high cleanliness steel |
| JP2015183259A (en) * | 2014-03-25 | 2015-10-22 | 新日鐵住金株式会社 | Method for melting high cleanliness steel |
| CN108823357A (en) * | 2018-07-09 | 2018-11-16 | 上海宽量节能投资有限公司 | A kind of degassing system and its degassing method based on flexible mechanical vacuum pump group |
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