JPH01225717A - Method for removing chromium from molten steel - Google Patents
Method for removing chromium from molten steelInfo
- Publication number
- JPH01225717A JPH01225717A JP63052099A JP5209988A JPH01225717A JP H01225717 A JPH01225717 A JP H01225717A JP 63052099 A JP63052099 A JP 63052099A JP 5209988 A JP5209988 A JP 5209988A JP H01225717 A JPH01225717 A JP H01225717A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- slag
- flux
- steel
- basicity
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 39
- 239000010959 steel Substances 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims description 11
- 239000011651 chromium Substances 0.000 title description 50
- 229910052804 chromium Inorganic materials 0.000 title description 7
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title description 6
- 230000004907 flux Effects 0.000 claims abstract description 25
- 230000001590 oxidative effect Effects 0.000 claims abstract description 15
- 229910000975 Carbon steel Inorganic materials 0.000 abstract description 10
- 238000007664 blowing Methods 0.000 abstract description 10
- 239000010962 carbon steel Substances 0.000 abstract description 10
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 abstract description 7
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 abstract description 7
- 239000000203 mixture Substances 0.000 abstract description 7
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 abstract description 5
- 230000033228 biological regulation Effects 0.000 abstract description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 abstract 1
- 229910001634 calcium fluoride Inorganic materials 0.000 abstract 1
- 229910052681 coesite Inorganic materials 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 229910052906 cristobalite Inorganic materials 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 abstract 1
- 239000000377 silicon dioxide Substances 0.000 abstract 1
- 235000012239 silicon dioxide Nutrition 0.000 abstract 1
- 239000007858 starting material Substances 0.000 abstract 1
- 229910052682 stishovite Inorganic materials 0.000 abstract 1
- 229910052905 tridymite Inorganic materials 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 239000002893 slag Substances 0.000 description 35
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 9
- 230000000694 effects Effects 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 239000011819 refractory material Substances 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000005261 decarburization Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 239000000292 calcium oxide Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000005262 decarbonization Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000005067 remediation Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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〉
この発明は、転炉吹錬後の溶鋼からクロム（Ｃｒ）分を
効果的に除去する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 effectively removing chromium (Cr) from molten steel after converter blowing.
〈従来技術とその課題〉
一般に、鋼中のＣｒ含有量が多くなれば冷間加工性及び
深絞り性などの加工特性の悪化を招くことが知られてお
り、そのため、自動車用冷延鋼板材等のような良加工性
の炭素鋼を溶製する場合には、溶鋼中のＣｒ含有量を０
．０３〜０．０５％以下に調整することが厳しく要求さ
れている。しかし、最近、転炉による炭素鋼溶製作業に
おいて、突発的なＣｒ含１１の上昇が起きるのを完全に
防止するのが次第に困難な状況となりつつあった。<Prior art and its problems> It is generally known that an increase in Cr content in steel leads to deterioration of processing properties such as cold workability and deep drawability. When melting carbon steel with good workability such as
．． It is strictly required to adjust the content to 0.03 to 0.05% or less. However, recently, it has become increasingly difficult to completely prevent a sudden increase in Cr content 11 in carbon steel melting operations using a converter.
なぜなら、転炉による炭素鋼の溶製作業においては、通
常、溶銑中へのスクラップの配合が行われているが、近
年、ステンレス鋼需要の伸びを反映して転炉配合原料た
るスクラップ中にステンレス鋼屑が混入する機会が増え
つつあったからである。This is because when melting carbon steel in a converter, scrap is normally mixed into hot metal, but in recent years, reflecting the growth in demand for stainless steel, stainless steel has been added to the scrap that is the raw material for converter mixing. This is because the chances of steel scrap getting mixed in were increasing.
勿論、スクラップの管理は一段と強化されてはいるもの
の、実際作業においては、依然として転炉吹錬後の炭素
鋼におけるＣｒ含有量の規格外れ発生の問題を根絶でき
ないのが実状であった。Of course, scrap management has been further strengthened, but in actual practice, it is still not possible to eradicate the problem of Cr content deviations from specifications in carbon steel after converter blowing.
そこで、上述のようなＣｒ含有量の規格外れが発生した
場合の対策として、転炉において酸素を吹き下げ、吹錬
を更に延長して脱Ｃｒを図る方法を講じることも行われ
ている。しかし、この場合には、溶銑中に溶は込んでい
たＣｒの一部が脱炭精錬の際に既に酸化されＣｒ酸化物
としてスラグ吊に移動していることから、低Ｃｒ化に限
界があり、また、この処理中における転炉耐火物の溶損
も激しくなるとの問題もあった。Therefore, as a countermeasure against the above-mentioned deviation of the Cr content from the specification, a method of removing Cr by blowing down oxygen in the converter and further extending the blowing period has been taken. However, in this case, there is a limit to the reduction in Cr because some of the Cr that had entered the hot metal has already been oxidized during decarburization and moved to the slag as Cr oxides. In addition, there was also the problem that the converter refractories were severely eroded during this treatment.
従って、Ｃｒ含有量規格外れの度合いの大きな溶鋼に対
しては“鋼種変更”を余儀無くさせられているのが現状
である。Therefore, it is currently necessary to "change the steel type" for molten steel whose Cr content is significantly out of specification.
一方、最近の鋼材需要の安定化傾向からスクラップはよ
り増加する気配を見せており、今後、更にスクラップが
多量にしかも安価に入手できるようになれば、炭素鋼溶
製に際して溶銑比を下げスクラップ比を上げる情勢とな
ることは目に見えている。従って、このような状況にな
ると、ステンレス鋼屑混入による鋼材のＣｒ含有量規格
外れの確率は益々高くなり、しかも規格外れ幅も一層大
きくなると考えられ、“鋼種変更”のみでは対処できな
くなることは明らかである。On the other hand, scrap is showing signs of increasing due to the recent stabilization of demand for steel materials, and if scrap becomes available in large quantities and at low prices, the hot metal ratio will be lowered to reduce the scrap ratio when making carbon steel. It is clear that the situation is likely to increase. Therefore, in such a situation, the probability that the Cr content of the steel material will be out of specification due to the contamination of stainless steel scraps will become higher and higher, and the range of deviations from the specification will also increase, and it will not be possible to deal with it simply by changing the steel type. it is obvious.
く課題を解決するための手段〉
本発明者等は、前述したように、スクラップ等を通じて
溶鋼へのＣｒの混入が今後益々増加するであろうことを
予想した場合、“転炉での酸素吹き下げ吹錬の延長”で
はＣｒ含有量規格外れの教法や低Ｃｒｍ（自動車用冷延
鋼板に供する炭素鋼等）の溶製に対処できないとの観点
から、炉外精錬による簡易で効果的な溶鋼脱Ｃｒの可能
性について研究を行ったところ、［転炉吹錬後の未脱酸
・未真空処理溶鋼を取鍋等の容器に収容し、この中で高
い酸化性を有しかつ塩基度の低いフラックスと接触させ
ると溶鋼の脱Ｃｒが効果的に進行し、転炉配合原料等か
らのＣｒ混入があったとしても、自動車用冷延鋼板等で
要求される厳しいＣｒ規制をも十分に満たす低Ｃｒ鋼を
安定して溶製することが可能となる」との知見が得られ
たのである。Means for Solving the Problems> As mentioned above, the present inventors predicted that the amount of Cr mixed into molten steel through scrap etc. would increase in the future. From the viewpoint that "extension of down-blowing" cannot deal with the Cr content that does not meet the standard and the melting of low Cr (carbon steel used for cold-rolled steel sheets for automobiles, etc.), a simple and effective method using out-of-furnace refining has been proposed. We conducted research on the possibility of removing Cr from molten steel, and found that [undeoxidized and unvacuum treated molten steel after converter blowing is stored in a container such as a ladle, and the molten steel has high oxidizability and basicity. When brought into contact with a low flux, chromium removal from molten steel progresses effectively, and even if chromium is mixed in from the converter blended raw materials, it is sufficient to meet the strict chromium regulations required for cold-rolled steel sheets for automobiles, etc. The findings showed that it is possible to stably produce low Cr steel that satisfies the requirements.
この発明は、上記知見に基づいてなされたものであり、
「容器内に収容した転炉吹錬後の溶鋼に酸化性の低塩基
度フラックスを接触させることにより、簡単かつ安定に
溶鋼の脱Ｃｒを行う点」に特徴を有するものである。This invention was made based on the above-mentioned knowledge, and it is based on the following: ``By bringing an oxidizing low basicity flux into contact with the molten steel after converter blowing stored in a container, molten steel can be easily and stably deCr-free. It is characterized by the fact that it performs
ここで、溶鋼を収容する容器は格別に制限されるもので
はないが、−船釣には取鍋が最も簡便で好ましいものと
言える。また、フラックスの酸化力の程度並びに塩基度
も格別に限定されるものではなく、溶鋼の用途やＣｒ含
有量等に応じて適宜後述する範囲程度に調整すれば良い
。そして、フラックス組成としては酸化鉄（鉄鉱石、ダ
スト、スケール等のＦｅ０分）とＳｉＯ□を主成分とし
、これに八ｉ、０．（酸性酸化物であって脱Ｃｒに効果
的であることに加え、取鍋等の溶鋼容器の耐火物がＡＩ
！ ｔ Ｏｘの場合に耐火物の溶損を防止する上で好ま
しい）。Here, the container for storing molten steel is not particularly limited, but a ladle is the most convenient and preferable for boat fishing. Further, the degree of oxidizing power and basicity of the flux are not particularly limited, and may be appropriately adjusted within the range described below depending on the use of the molten steel, the Cr content, and the like. The flux composition is mainly composed of iron oxide (Fe0 content of iron ore, dust, scale, etc.) and SiO□, with 8i, 0. (In addition to being an acidic oxide and effective in removing Cr, the refractories of molten steel containers such as ladles are
! (This is preferable in order to prevent melting of refractories in the case of tOx).
Ｃａｂ（塩基度の調整や耐火物の溶損防止に有効）。Cab (effective for adjusting basicity and preventing erosion of refractories).
Ｍｇ０（耐火物の溶損防止に有効）及びＣａＦｚ（スラ
グの滓化性向上作用を有する）の１種又は２種以上を加
えた組成とするのが良く、これを混合或いは合成したも
のが本発明の脱Ｃｒ処理用として好適である。It is best to have a composition containing one or more of Mg0 (effective for preventing corrosion damage of refractories) and CaFz (having an effect of improving slag slag formation), and a mixture or synthesis of these is preferred. It is suitable for the Cr removal treatment of the invention.
以下、このフラックスの成分、塩基度及び酸化力の程度
について更に詳述する。The components, basicity and oxidizing power of this flux will be explained in more detail below.
本発明に係る脱Ｃｒ処理を効果的に行うためには、フラ
ックス成分の選択の際、次の２点に留意することが重要
である。In order to effectively perform the Cr removal treatment according to the present invention, it is important to keep the following two points in mind when selecting flux components.
第１点は、“スラグが有する酸化力”が同程度である場
合にはより低塩基性のスラグ組成となるように成分を選
択することである。なぜなら、脱Ｃｒ処理によってスラ
グ中に生成するＣｒ、Ｏ，は弱いながら塩基性の酸化物
であると考えられ、復ＣｒＬないようにスラグ中Ｃｒｚ
Ｏ３の活量を下げるにはスラグは低塩基度である方が有
効だからである。The first point is to select components so that the slag composition has a lower basicity when the "oxidizing power of the slag" is at the same level. This is because Cr and O, which are generated in the slag by the Cr removal process, are thought to be weak but basic oxides, and Crz in the slag is
This is because it is more effective for the slag to have a low basicity in order to lower the activity of O3.
第１図は、種々の酸化鉄活量（ａｙ、。）におけるスラ
グの塩基度（（ＣａＯ＋ＭｇＯ＋Ｍｎ０）／ （Ｓｉ
Ｏ２＋Ａ１ｚＯ３）ｌ とＣｒの分配比（（Ｃｒ） ／
［Ｃｒ］ ）との関係を示したグラフである。ここで
、（ｌＺＦａｏはスラグ中のＦｅＯ濃度、即ち（Ｆｅｄ
）とスラグの塩基度とによってｒ Ｔｕｒｋｄｏｇａｎ
及びＰｅａｒｓｏｎによる（ｌ ＦｔｔＯ等活量線図（
”Ｊｏｕｒｎａｌ ｏｆ ｔｈｅ Ｉｒｏｎ ａｎｄ
５ｔｅｅｌ Ｔｎｓｔ−ｉｔｕｔｅ″１９５３ Ｍ＾Ｒ
ＣＨ，２１７〜２２３真） Ｊから推定されるところの
“スラグの酸化力を示す指標”である。この第１図から
も、同じａ ＦｅＯを有するスラグであってもスラグの
塩基度が低い程クロムの分配比（（Ｃｒ） ／ ［Ｃｒ
］ ）の値が大きくなることが分かる。Figure 1 shows the basicity of slag ((CaO+MgO+Mn0)/(Si
O2+A1zO3)l and Cr distribution ratio ((Cr)/
[Cr] ) is a graph showing the relationship with [Cr]. Here, (lZFao is the FeO concentration in the slag, that is, (Fed
) and the basicity of the slag.
and Pearson's (l FttO isoactivity diagram (
”Journal of the Iron and
5teel Tnst-itute"1953 M^R
CH, 217-223 true) is an "indicator of the oxidizing power of slag" estimated from J. From Fig. 1, even if the slag has the same aFeO, the lower the basicity of the slag, the lower the chromium distribution ratio ((Cr)/[Cr
] It can be seen that the value of ) increases.
なお、−Ｃにはスラグの塩基度は１以下であることが望
ましいが、２以下であっても良好な効果が得られ、また
、３以下であっても他の条件により脱Ｃｒの進行を確保
することができる。Although it is desirable for the -C basicity of the slag to be 1 or less, a good effect can be obtained even if it is 2 or less, and even if it is 3 or less, the progress of Cr removal can be controlled by other conditions. can be secured.
第２点は、“スラグが強い酸化力を有するようにフラッ
クス成分を選ぶ”ことである。なぜなら、スラグによる
溶鋼中Ｃｒの酸化除去は、スラグの強い酸化力によって
脱炭を伴いながら脱Ｃｒがなされる現象によって行われ
るからである。The second point is to "select flux components so that the slag has strong oxidizing power." This is because the oxidation removal of Cr in molten steel by slag is carried out by a phenomenon in which Cr is removed along with decarburization due to the strong oxidizing power of slag.
この点も、先に示した第１図から明らかである。This point is also clear from FIG. 1 shown above.
即ち、第１図を検討すると、同塩基度のスラグでは高い
αＦ０゜を持つスラグの方が高い（Ｃｒ）／ ［Ｃｒ］
値となることが分かる筈である。That is, considering Figure 1, among slags with the same basicity, the slag with a higher αF0° has a higher (Cr)/[Cr]
It should be clear that the value is the same.
そして、スラグの塩基度が１．５〜３の場合には（Ｆｅ
Ｏ）濃度は２０〜３０重量％以上であることが望まし
く、それ以外の領域では前記値より高い方が望ましい。When the basicity of slag is 1.5 to 3, (Fe
O) The concentration is desirably 20 to 30% by weight or more, and in other areas it is desirably higher than the above value.
更に、この点を、−船釣なスラグの酸化力推定基準とし
て用いられる（Ｔ、Ｆｅ）によって検討しても同様の結
果が得られる。Furthermore, similar results can be obtained by examining this point using (T, Fe), which is used as a standard for estimating the oxidizing power of slag.
即ち、第２図は、３種の比較的低いフラックス配合塩基
度（（ＣａＯ＋ＭｇＯ／５ｉＯｚ＋ＡｆｚＯｔ））別に
、Ｃｒ率に及ぼ（Ｔ、Ｆｅ）の影響を示したクラツであ
るが、この第２図からも、例えば脱Ｃｒ率が２０％を超
える脱Ｃｒフラックスを得るにはスラグの（Ｔ、Ｆｅ）
を、Ｓ ｉ Ｏｚ ＋ ＡＩ！ ｚ Ｏｚ
Ｓ ｉ Ｏｚ ＋ ＡＪ ｚ Ｏｚ
Ｓｉｎｇ ＋ Ａｊ！ｚｏ ３
なる高い値に調整する必要のあることが分かる。In other words, Figure 2 shows the influence of (T, Fe) on the Cr rate for each of the three relatively low basicities of flux blends ((CaO+MgO/5iOz+AfzOt)). For example, in order to obtain a Cr-free flux with a Cr-free rate exceeding 20%, the (T, Fe) of the slag is
, S i Oz + AI! z Oz S i Oz + AJ z Oz Sing + Aj! It can be seen that it is necessary to adjust to a high value of zo 3 .
さて、本発明に係る脱Ｃｒ処理を施すに際して転炉スラ
グは除滓しておくことが望ましいが、復燐があまり問題
とならない場合には、転炉滓を少量残した状態のままで
上記の性質をもつスラグ成分が得されるように添加フラ
ックス成分を制御しても良い。Now, it is desirable to remove the converter slag when carrying out the Cr-removal treatment according to the present invention, but if rephosphorization is not a big problem, the above-mentioned procedure can be carried out with a small amount of converter slag remaining. The added flux component may be controlled so as to obtain a slag component with specific properties.
また、フラックスの添加方法としては溶鋼上部からの投
入法で十分であるが、溶鋼中へインジェクションする場
合の方がより効果的である。Furthermore, although it is sufficient to add flux from the top of the molten steel, it is more effective to inject it into the molten steel.
フラックスの添加量は目的とする脱Ｃｒ量及び同時に起
きる脱炭量等によって決定されるが、通常１０〜５０
ｋｇ／１−ｓｔｅｅｌでよい。これ以上になると、フォ
ーミング現象によってスラグが溢れたり溶鋼の温度降下
が大きくなったりするので不適当である。但し、取鍋の
嵩上げやフラックス添加後の昇温が可能であれば５０〜
１００ ｋｇ／１−ｓｔｅｅｌであっても差し支えない
。The amount of flux added is determined depending on the target amount of Cr removal and the amount of simultaneous decarburization, but it is usually 10 to 50.
kg/1-steel. If it exceeds this range, it is inappropriate because the slag overflows due to the forming phenomenon and the temperature drop of the molten steel increases. However, if it is possible to raise the height of the ladle or increase the temperature after adding flux, the temperature should be 50~
It may be 100 kg/1-steel.
ところで、本発明に係る処理において溶鋼とスラグの攪
拌が重要なことは言うまでもないが、その攪拌方法とし
ては一般的なアルゴンガスによるバブリング攪拌は勿論
、転炉出鋼時にフラックスを添加し、溶鋼の自然落下に
よる攪拌を利用することも有効である。これは、本発明
にかかる処理がフラックスの酸化力さえ十分であれば速
やかに進行する性質のものであるためである。Incidentally, it goes without saying that stirring of molten steel and slag is important in the treatment according to the present invention, but the stirring method includes not only the general bubbling stirring using argon gas, but also the addition of flux at the time of tapping the molten steel from the converter. It is also effective to use agitation due to natural falling. This is because the treatment according to the present invention proceeds quickly as long as the oxidizing power of the flux is sufficient.
脱Ｃｒ処理後のスラグは、次工程である脱酸やＲＨ処理
での復Ｃｒを防止するため除滓することが望ましいが、
塊状の生石灰等でスラグを固めてスラグチルする方法を
採用してもよい。It is desirable to remove slag from the slag after the Cr removal treatment in order to prevent re-Cr in the next step of deoxidation and RH treatment.
A method of solidifying the slag with lumps of quicklime or the like and performing slag chilling may be adopted.
次に、実施例によって本発明の効果を比較例と対比しな
がら説明する。Next, the effects of the present invention will be explained using Examples while comparing them with Comparative Examples.
〈実施例〉
まず、タンマン炉を使用して炭素鋼２ ｋｇをＭｇＯル
ツボ内で大気溶解して転炉吹錬後のものと同じ状態の溶
鋼を再現し、これを１６０（ｌに保持した。次いで、こ
の溶鋼に第１表で示す条件のフラックス１００ｇを添加
し、アルゴンガス吹込みによりバブリング攪拌して脱Ｃ
ｒ処理を行った。<Example> First, 2 kg of carbon steel was melted in the atmosphere in an MgO crucible using a Tammann furnace to reproduce molten steel in the same state as that after converter blowing, and this was maintained at 160 (l). Next, 100 g of flux under the conditions shown in Table 1 was added to this molten steel, and decarbonized by bubbling stirring by blowing argon gas.
r treatment was performed.
この脱Ｃｒ処理の結果を第１表に併せて示す。The results of this Cr removal treatment are also shown in Table 1.
第１表に示される結果からも明らかなように、酸化性が
高く、かつ塩基度の低いフラックスを使用した本発明例
（試験番号１〜６）では、フラックスとの接触によって
脱炭を伴いながら溶鋼の脱Ｃｒが良好に進行したことが
分かる。As is clear from the results shown in Table 1, in the examples of the present invention (test numbers 1 to 6) using fluxes with high oxidizing properties and low basicity, decarburization occurred due to contact with the flux. It can be seen that the removal of Cr from the molten steel progressed well.
これに対して、試験番号７（比較例）の結果は、低塩基
度フラックスを用いたとしても、スラグ中のＴ、 Ｆｅ
値が小さくて酸化力が不十分な場合には脱Ｃｒが殆んど
進行しないことを示している。On the other hand, the results of Test No. 7 (comparative example) showed that even if a low basicity flux was used, T and Fe in the slag were
This shows that when the value is small and the oxidizing power is insufficient, Cr removal hardly progresses.
また、試験番号８（比較例）は、塩基度の高いフラック
スを用いた例であるが、その結果からも、フラックスが
強い酸化力を有していたとしても塩基度が高い場合には
十分な脱Ｃｒを行えないことが分かる。In addition, test number 8 (comparative example) is an example in which a flux with high basicity was used, and the results also show that even if the flux has strong oxidizing power, it is insufficient if the basicity is high. It can be seen that Cr removal cannot be performed.
なお、これまでの説明では、転炉溶製された溶鋼の脱Ｃ
ｒを主体に説明してきたが、本発明法は電気炉を用いて
スクラップのみから炭素鋼を溶製する場合にも適用でき
ることは言うまでもない。In addition, in the explanation so far, the decarbonization of molten steel melted in a converter
Although the method of the present invention has been mainly explained using R, it goes without saying that the method of the present invention can also be applied to the case where carbon steel is produced from only scrap using an electric furnace.
く効果の総括〉
以上に説明した如く、この発明によれば、溶鋼の脱Ｃｒ
処理を簡単かつ効果的に実施することができ、溶鋼のＣ
ｒ規格外れの救済や高品質炭素鋼の安定溶製が配合原料
に左右されることなく極めて容易となるなど、産業上有
用な効果がもたらされるのである。Summary of Effects> As explained above, according to the present invention, it is possible to remove Cr from molten steel.
The treatment can be carried out easily and effectively, and the C of molten steel can be easily and effectively carried out.
Industrially useful effects are brought about, such as remediation of out-of-spec specifications and stable melting of high-quality carbon steel, which is extremely easy regardless of the blended raw materials.
第１図は、種々の酸化力を有するスラグの塩基度とＣｒ
分配比との関係を示すグラフである。
第２図は、種々のフラックス配合塩基度下でのスラグの
（Ｔ、Ｆｅ）と脱Ｃｒ率との関係を示すグラフである。Figure 1 shows the basicity and Cr of slag with various oxidizing powers.
It is a graph showing the relationship with the distribution ratio. FIG. 2 is a graph showing the relationship between (T, Fe) of the slag and the Cr removal rate under various flux blend basicities.
Claims (1)
度フラックスを接触させることを特徴とする、溶鋼の脱
クロム方法。A method for dechromizing molten steel, which is characterized by bringing an oxidizing low basicity flux into contact with molten steel after being blown in a converter housed in a container.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5209988A JPH0692614B2 (en) | 1988-03-05 | 1988-03-05 | Dechromization method of molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5209988A JPH0692614B2 (en) | 1988-03-05 | 1988-03-05 | Dechromization method of molten steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01225717A true JPH01225717A (en) | 1989-09-08 |
| JPH0692614B2 JPH0692614B2 (en) | 1994-11-16 |
Family
ID=12905397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5209988A Expired - Lifetime JPH0692614B2 (en) | 1988-03-05 | 1988-03-05 | Dechromization method of molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0692614B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04103710A (en) * | 1990-08-22 | 1992-04-06 | Sumitomo Metal Ind Ltd | Method for removing chromium in molten steel |
| JPH04103711A (en) * | 1990-08-22 | 1992-04-06 | Sumitomo Metal Ind Ltd | Method for removing chromium in molten steel |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5499028A (en) * | 1978-01-21 | 1979-08-04 | Kawaguchi Seikou Kk | Refining method to remove acidic oxide forming element from feeni * feeco or feeniico alloy steel |
-
1988
- 1988-03-05 JP JP5209988A patent/JPH0692614B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5499028A (en) * | 1978-01-21 | 1979-08-04 | Kawaguchi Seikou Kk | Refining method to remove acidic oxide forming element from feeni * feeco or feeniico alloy steel |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04103710A (en) * | 1990-08-22 | 1992-04-06 | Sumitomo Metal Ind Ltd | Method for removing chromium in molten steel |
| JPH04103711A (en) * | 1990-08-22 | 1992-04-06 | Sumitomo Metal Ind Ltd | Method for removing chromium in molten steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0692614B2 (en) | 1994-11-16 |
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