JPH04276009A - Decarbonized refining method for chromium-containing molten steel - Google Patents
Decarbonized refining method for chromium-containing molten steelInfo
- Publication number
- JPH04276009A JPH04276009A JP3729791A JP3729791A JPH04276009A JP H04276009 A JPH04276009 A JP H04276009A JP 3729791 A JP3729791 A JP 3729791A JP 3729791 A JP3729791 A JP 3729791A JP H04276009 A JPH04276009 A JP H04276009A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- chromium
- decarburization
- slag
- amount
- 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- Withdrawn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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 55
- 239000010959 steel Substances 0.000 title claims abstract description 55
- 239000011651 chromium Substances 0.000 title claims abstract description 25
- 229910052804 chromium Inorganic materials 0.000 title claims abstract description 21
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 238000007670 refining Methods 0.000 title claims abstract description 16
- 238000000034 method Methods 0.000 title claims description 18
- 239000002893 slag Substances 0.000 claims abstract description 33
- 239000007789 gas Substances 0.000 claims abstract description 23
- 230000004907 flux Effects 0.000 claims abstract description 6
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 4
- 238000005261 decarburization Methods 0.000 claims description 41
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 5
- 229910001882 dioxygen Inorganic materials 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 25
- 229910052760 oxygen Inorganic materials 0.000 abstract description 25
- 239000001301 oxygen Substances 0.000 abstract description 25
- 238000007664 blowing Methods 0.000 abstract description 21
- 238000007254 oxidation reaction Methods 0.000 abstract description 6
- 230000003647 oxidation Effects 0.000 abstract description 5
- 238000005262 decarbonization Methods 0.000 abstract 2
- 238000010304 firing Methods 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 8
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 150000002926 oxygen Chemical class 0.000 description 2
- 101000582320 Homo sapiens Neurogenic differentiation factor 6 Proteins 0.000 description 1
- 102100030589 Neurogenic differentiation factor 6 Human genes 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 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】含クロム溶鋼の脱炭精錬法におい
て、溶鋼中のクロム酸化を抑え、効率よく脱炭を行なう
含クロム溶鋼の脱炭精錬法に関する。[Industrial Application Field] This invention relates to a decarburizing refining method for chromium-containing molten steel, which suppresses chromium oxidation in the molten steel and efficiently decarburizes the molten steel.
【０００２】0002
【従来の技術】従来の含クロム溶鋼の脱炭精錬法では、
脱炭時のスラグ量および溶鋼中成分を規制した従来技術
は認められず、ガス供給方法に関するものが殆どである
。[Prior art] In the conventional decarburization refining method of chromium-containing molten steel,
There is no prior art that regulates the amount of slag and the components in molten steel during decarburization, and most of them relate to gas supply methods.
【０００３】例えば特開昭５５−１５２１３号は、浴面
下に酸素及び不活性ガスを吹込んで脱炭を行うと同時に
該酸素量の少なくとも０．２倍に相当する量を浴面上よ
り供給し、溶鋼を昇熱せしめる方法であるが、この方法
では浴面上より供給される酸素は、二次燃焼反応に大半
が使用されるため、脱炭反応に使用される量は小さく、
又スラグの状態により脱炭に使用される酸素量が変化す
るものと認められ、従って脱炭速度のばらつきも大きく
難点がある。For example, JP-A-55-15213 discloses that decarburization is carried out by blowing oxygen and an inert gas under the bath surface, and at the same time an amount equivalent to at least 0.2 times the amount of oxygen is supplied from above the bath surface. However, in this method, most of the oxygen supplied from above the bath surface is used for the secondary combustion reaction, so the amount used for the decarburization reaction is small.
Furthermore, it is recognized that the amount of oxygen used for decarburization varies depending on the state of the slag, and therefore there is a drawback that the decarburization rate varies widely.
【０００４】又特開昭５９−１６６６１７号は、上吹き
酸素、底吹き酸素または不活性ガスを用いる複合吹錬法
で含クロム溶鋼を脱炭するに際し、鋼中［Ｃ］濃度の維
持に応じて、ランス高さおよび上吹き酸素量を制御する
方法であるが、この方法では上吹き酸素の条件を［Ｃ］
濃度によって変更するが、この条件はスラグの条件では
変化させないので脱炭速度にばらつきを生ずる難点をも
つものである。[0004] JP-A-59-166617 also discloses that when chromium-containing molten steel is decarburized by a combined blowing method using top-blown oxygen, bottom-blown oxygen, or inert gas, a This method controls the lance height and the amount of top-blown oxygen, but in this method, the conditions of top-blown oxygen are set to [C]
This condition is changed depending on the concentration, but since this condition is not changed under the slag condition, it has the disadvantage that the decarburization rate varies.
【０００５】なお、普通鋼脱炭において、スラグを少な
くすれば好結果が得られるとの報告もあるが、上吹き条
件との対応を示した従来技術は認められない。[0005] In the decarburization of ordinary steel, it has been reported that good results can be obtained by reducing the amount of slag, but no prior art has been found that shows correspondence with top blowing conditions.
【０００６】[0006]
【発明が解決しようとする課題】含クロム溶鋼の複合脱
炭精錬において、上吹き条件との関係でスラグ条件を特
定範囲に維持することによりクロムの酸化を抑え、効率
よく脱炭を行い、併せて還元用Ｓｉ添加量の低減、精錬
時間の短縮を図るものである。[Problem to be solved by the invention] In the composite decarburization refining of chromium-containing molten steel, by maintaining the slag conditions within a specific range in relation to the top blowing conditions, oxidation of chromium can be suppressed, decarburization can be carried out efficiently, and at the same time This aims to reduce the amount of Si added for reduction and shorten the refining time.
【０００７】[0007]
【課題を解決するための手段】本発明は上述の課題を有
利に解決したものであり、その要旨は炭素を０．３ｗｔ
％以上含有する含クロム溶鋼の浴面下および浴面上から
酸素ガスを吹込むとともに、浴面上に吹込んだ酸素ガス
の火点部のスラグ量が下記（１）式を満足する条件下で
脱炭を行なうことを特徴とする含クロム溶鋼の脱炭精錬
法である。[Means for Solving the Problems] The present invention advantageously solves the above-mentioned problems, and the gist thereof is to reduce the amount of carbon by 0.3wt.
Oxygen gas is blown from below and above the bath surface of the chromium-containing molten steel containing chromium-containing molten steel, and the slag amount at the flashing point of the oxygen gas blown onto the bath surface satisfies the following formula (1). This is a decarburization refining method for chromium-containing molten steel, which is characterized by decarburizing it in the process.
【０００８】[0008]
【数２】[Math 2]
【０００９】但し
［％Ｓｉ］：炉内装入時の溶鋼中［Ｓｉ］濃度（ｗｔ％
）
ＷＳ：単位溶鋼重量当りの持込みスラグ量（Ｋｇ／Ｔ）
ＷＦ：単位溶鋼重量当りの炉内装入後のフラックス添加
量（Ｋｇ／Ｔ）
Ｌ／Ｌ０：上吹きガスによる浴面の凹み率以下本発明に
ついて詳細に説明する。本発明の含クロム溶鋼の脱炭精
錬は図１に例示するように複合脱炭精錬法によるもので
あり、（ａ）は静止浴状態、（ｂ）はガス吹込み状態を
示し、図中１は上吹きランス、２は底吹き羽口、３は溶
鋼、４はスラグを示す。[0009] However, [%Si]: [Si] concentration in molten steel (wt%
) WS: Amount of slag brought in per unit weight of molten steel (Kg/T)
WF: Amount of flux added after charging into the furnace per unit weight of molten steel (Kg/T) L/L0: Ratio of depression of bath surface due to top-blown gas The present invention will be described in detail below. The decarburization refining of chromium-containing molten steel of the present invention is performed by a composite decarburization refining method as illustrated in FIG. 2 indicates a top blowing lance, 2 indicates a bottom blowing tuyere, 3 indicates molten steel, and 4 indicates slag.
【００１０】而して本発明は、含クロム溶鋼の複合吹錬
において、上吹き酸素の火点で高温域をつくり、この部
分で過飽和の酸素を含有させた溶鋼となし、これと溶鋼
中［Ｃ］とを反応させることにより、有効に脱炭が進行
することに着目したものである。即ち上吹き酸素の火点
部にスラグが存在すれば過飽和の酸素がクロムを酸化し
、Ｃｒ２Ｏ３となってスラグへ移行するので、本発明に
おいてはこの火点部にスラグを存在せしめず、脱炭を効
率よく進行せしめる条件として、下記の式の状態を維持
せしめることを特徴とするものである。[0010] Accordingly, the present invention creates a high-temperature region at the fire point of top-blown oxygen in the composite blowing of chromium-containing molten steel, creates molten steel containing supersaturated oxygen in this area, and [ This study focuses on the fact that decarburization progresses effectively by reacting with C]. In other words, if slag exists in the hot spot of top-blown oxygen, supersaturated oxygen oxidizes chromium, converts it to Cr2O3, and transfers to slag. Therefore, in the present invention, slag is not present in this hot spot, and decarburization is performed. As a condition for efficiently proceeding, it is characterized by maintaining the state of the following formula.
【００１１】[0011]
【数３】[Math 3]
【００１２】但し
［％Ｓｉ］：炉内装入時の溶鋼中［Ｓｉ］濃度（ｗｔ％
）
ＷＳ：単位溶鋼重量当りの持込みスラグ量（Ｋｇ／Ｔ）
ＷＦ：単位溶鋼重量当りの炉内装入後のフラックス添加
量（Ｋｇ／Ｔ）
Ｌ／Ｌ０：上吹きガスによる浴面の凹み率この条件を図
１に基づいて詳細に説明する。図１（ａ）の静止浴状態
での鋼浴深さＬ０の溶鋼３に上吹きおよび底吹きのガー
ス を供給することで、（ｂ）の状態になる。ここで
、上吹きガスによる浴面のー凹み深さＬは（２）、（３
）式によって表される。[0012] However, [%Si]: [Si] concentration in molten steel at the time of entering the furnace (wt%
) WS: Amount of slag brought in per unit weight of molten steel (Kg/T)
WF: Amount of flux added after charging into the furnace per unit weight of molten steel (Kg/T) L/L0: Rate of depression of bath surface due to top blowing gas These conditions will be explained in detail based on FIG. 1. By supplying top-blown and bottom-blown girths to the molten steel 3 at the steel bath depth L0 in the stationary bath state of FIG. 1(a), the state shown in FIG. 1(b) is achieved. Here, the depth L of the depression on the bath surface due to the top-blown gas is (2), (3
) is expressed by the formula.
【００１３】Ｌ＝Ｌｈ・ｅｘｐ（−０．７８ｈ／Ｌｈ）
… （２）
Ｌｈ＝６３．０（ＱＴ／ｎｄ）２／３ … （３）
但し
Ｌ：上吹きガスによる浴面の凹み深さ（ｍｍ）ｈ：上吹
きランスギャップ（ｍｍ）
ＱＴ：上吹きガス流量（Ｎｍ３／Ｈｒ）ｎ：上吹きラン
ス孔数
ｄ：上吹きランス孔径（ｍｍ）
つまり、ランスギャップを小さくし、吹き込むガスの流
速を大きくとるこによって、浴面凹み深さＬが大きくな
る。一般に鋼浴中に存在するスラグは、溶鋼に比べ、比
重が１／２以下であり、溶鋼上に存在する。上吹きラン
スよりガスを供給することにより、スラグは炉周囲には
ねのけられ、ガスが吹き込まれる部分には存在しない。[0013]L=Lh・exp(-0.78h/Lh)
… (2) Lh=63.0 (QT/nd)2/3 … (3)
However, L: Depth of depression in the bath surface due to top-blown gas (mm) h: Top-blowing lance gap (mm) QT: Top-blowing gas flow rate (Nm3/Hr) n: Number of top-blowing lance holes d: Top-blowing lance hole diameter ( mm) That is, by reducing the lance gap and increasing the flow rate of the blown gas, the depth L of the bath surface depression becomes larger. Generally, slag present in a steel bath has a specific gravity less than half that of molten steel, and is present on molten steel. By supplying gas from the top blowing lance, slag is thrown around the furnace and does not exist in the area where the gas is blown.
【００１４】上吹きガスによる浴面の凹み率Ｌ／Ｌ０が
大きいほどその傾向が強くなる。[0014] The greater the depression ratio L/L0 of the bath surface due to top-blown gas, the stronger this tendency becomes.
【００１５】一方、脱炭時に存在する単位溶鋼重量当り
のスラグ量Ｗは（４）式によって表される。On the other hand, the amount W of slag per unit weight of molten steel present during decarburization is expressed by equation (4).
【００１６】
Ｗ＝２１．３９［ｗｔ％Ｓｉ］＋ＷＳ＋ＷＦ …
（４）つまり、炉内装入時に溶鋼中に存在する［ｗｔ％
Ｓｉ］は脱炭前に酸化され、ＳｉＯ２としてスラグへ移
行する。［Ｓｉ］の酸化によって生成するスラグ量が２
１．３９［ｗｔ％Ｓｉ］に相当する。この値に持込みス
ラグ量ＷＳおよび添加フラック量ＷＦを加えた値がスラ
グ量となる。[0016] W=21.39[wt%Si]+WS+WF...
(4) In other words, [wt%
Si] is oxidized before decarburization and transferred to the slag as SiO2. The amount of slag generated by oxidation of [Si] is 2
This corresponds to 1.39 [wt%Si]. The value obtained by adding the brought-in slag amount WS and the added flux amount WF to this value becomes the slag amount.
【００１７】スラグ量が少ないほど、また浴面の凹み率
が大きいほど上吹きガス直下に存在するスラグが少なく
なり、溶鋼表面が露出することになる。この関係により
（１）式が導出される。[0017] The smaller the amount of slag is, and the greater the concavity ratio of the bath surface, the less slag exists directly under the top-blown gas, and the more the molten steel surface is exposed. Equation (1) is derived from this relationship.
【００１８】図２に［Ｃ］濃度が０．５〜１．５ｗｔ％
の範囲における２１．３９［ｗｔ％Ｓｉ］＋ＷＳ＋ＷＦ
と脱炭酸素効率の関係を示す。横軸の値が２５０以下、
即ち（１）式の関係が成り立つ範囲において、脱炭酸素
効率が高位に安定する。FIG. 2 shows that the [C] concentration is 0.5 to 1.5 wt%.
21.39[wt%Si]+WS+WF in the range of
The relationship between decarburization and oxygen efficiency is shown. The value on the horizontal axis is 250 or less,
That is, the decarburization oxygen efficiency is stabilized at a high level within the range where the relationship of formula (1) holds.
【００１９】なお、脱炭酸素効率は供給した酸素の中で
脱炭反応に使用された酸素の比率を示す。Note that the decarburization oxygen efficiency indicates the proportion of oxygen used for the decarburization reaction in the supplied oxygen.
【００２０】又、本発明において、処理対象クロム含有
溶鋼として、炭素量０．３ｗｔ％以上のものとした理由
は、次記の如く本発明の効果を有効に得る範囲として限
定するものである。Further, in the present invention, the reason why the chromium-containing molten steel to be treated has a carbon content of 0.3 wt% or more is to limit the range in which the effects of the present invention can be effectively obtained as described below.
【００２１】図３に溶鋼中［Ｃ］濃度と脱炭酸素効率の
関係を示す。［Ｃ］濃度が０．３ｗｔ％未満では急激に
脱炭酸素効率が低下する。つまり、溶鋼中のＣｒの酸化
が進行し、スラグ中のＣｒ２Ｏ３の量および濃度が急激
に上昇する。このような状態では、上吹きガスの供給直
下に溶鋼面が露出していても、脱炭反応に対して十分な
効果は得られない。FIG. 3 shows the relationship between the [C] concentration in molten steel and the decarburization oxygen efficiency. When the [C] concentration is less than 0.3 wt%, the decarburization oxygen efficiency decreases rapidly. That is, oxidation of Cr in the molten steel progresses, and the amount and concentration of Cr2O3 in the slag rapidly increases. In such a state, even if the molten steel surface is exposed directly under the supply of top-blown gas, a sufficient effect on the decarburization reaction cannot be obtained.
【００２２】[0022]
【作用】含クロム溶鋼の脱炭精錬では、下記■式で示さ
れる脱炭反応と同時に■式で示されッル溶鋼中Ｃｒの酸
化反応も進行する。[Operation] In the decarburization refining of chromium-containing molten steel, the oxidation reaction of Cr in the molten steel proceeds as shown by the following equation (2) at the same time as the decarburization reaction shown by the following equation (1).
【００２３】
［Ｃ］＋１／２ＣＯ２ → ＣＯ（ｇ） …
■２［Ｃｒ］＋３／２Ｏ２ → （Ｃｒ２Ｏ３）
… ■鋼浴下部および鋼浴上面より酸素ガスを供給
する複合吹錬法において、上吹き酸素火点部にスラグが
存在した場合、■式の反応が進行しやすくなり、（Ｃｒ
２Ｏ３）がスラグへ移行する。上吹きガスの鋼浴表面に
届くガス流速を上げればガス供給部に存在するスラグが
少なくなり、■式の反応の進行が抑制されて、■式の脱
炭反応が効率よく進行することになる。[C]+1/2CO2 → CO(g)...
■2[Cr]+3/2O2 → (Cr2O3)
... ■In the combined blowing method in which oxygen gas is supplied from the lower part of the steel bath and the upper surface of the steel bath, if slag exists at the top blowing oxygen hot spot, the reaction of formula (■) tends to proceed, and (Cr
2O3) is transferred to slag. If the flow rate of the top-blown gas that reaches the steel bath surface is increased, the amount of slag present in the gas supply section will be reduced, the progress of the reaction in formula (1) will be suppressed, and the decarburization reaction in formula (2) will proceed efficiently. .
【００２４】脱炭反応は［Ｃ］濃度によって律速過程が
変化する。低［Ｃ］濃度側では律速過程は［Ｃ］の移動
であり、鋼浴の撹拌を強化することによって［Ｃ］の移
動が促進されて、脱炭速度が増大する。この状態で、ス
ラグ量および上吹きガスの吹込み強さを制御しても脱炭
速度の向上にはつながらない。The rate-determining process of the decarburization reaction changes depending on the [C] concentration. On the low [C] concentration side, the rate-determining process is the movement of [C], and by strengthening the stirring of the steel bath, the movement of [C] is promoted and the decarburization rate increases. In this state, even if the amount of slag and the blowing strength of the top blowing gas are controlled, the decarburization rate will not improve.
【００２５】一方、高［Ｃ］濃度側では鋼浴への酸素の
供給が律速過程であり、鋼浴への酸素の供給量を増大す
ることで脱炭速度が向上する。したがって、存在するス
ラグ量を少なくし、かつ、上吹きガスの鋼浴表面に届く
ガス流速を上げて、露出する鋼浴表面を大きくすれば、
酸素の供給量が増大し、脱炭速度が増大する。On the other hand, on the high [C] concentration side, the supply of oxygen to the steel bath is the rate-determining process, and the decarburization rate is improved by increasing the amount of oxygen supplied to the steel bath. Therefore, by reducing the amount of slag present and increasing the flow rate of the top-blown gas that reaches the steel bath surface, the exposed steel bath surface can be enlarged.
The amount of oxygen supplied increases and the decarburization rate increases.
【００２６】[0026]
【実施例】ＳＵＳ３０４ステンレス鋼（１８ｗｔ％Ｃｒ
−８ｗｔ％Ｎｉ）６０ｔｏｎ処理を前提とし、図１（ｂ
）に示す実施態様で図４（ａ）のガス供給パターンで実
施した。図４（ｂ）は比較例におけるガス供給パターン
を示す。[Example] SUS304 stainless steel (18wt%Cr
-8wt%Ni)60ton processing, Figure 1(b)
) was carried out using the gas supply pattern shown in FIG. 4(a). FIG. 4(b) shows a gas supply pattern in a comparative example.
【００２７】脱炭精錬は、表１の条件で実施した。なお
本発明の実施例はスラグ量、フラックス量を少なくする
とともにＬ／Ｌ０を大 きな範囲にとり前記（１）式
を満足する条件下に精錬を実施した。比較例は従来法と
して一般的に実施されている方法と認められる特開昭５
５−１５２１３号の方法に従った。[0027] The decarburization refining was carried out under the conditions shown in Table 1. In the examples of the present invention, refining was carried out under conditions that satisfied the above formula (1) by reducing the amount of slag and flux and setting L/L0 within a large range. The comparative example is JP-A No. 5, which is recognized as a commonly practiced conventional method.
The method of No. 5-15213 was followed.
【００２８】[0028]
【表１】[Table 1]
【００２９】[0029]
【表２】[Table 2]
【００３０】実施結果を表２に示す。表中平均脱炭効率
は［Ｃ］≧０．３％での値、還元用Ｓｉ原単位及び精錬
時間はＮｏ６の例を１００として換算した値である。The results are shown in Table 2. In the table, the average decarburization efficiency is the value when [C]≧0.3%, and the Si consumption unit for reduction and the refining time are the values converted with the example No. 6 as 100.
【００３１】[0031]
【発明の効果】本発明方法によると、含クロム溶鋼の脱
炭精錬において、脱炭効率が向上し、還元用Ｓｉの添加
量を低減でき、脱炭速度が向上し、精錬時間を短縮でき
る。さらに全体的にはスラグ量が減少し、成分的中率も
向上する等優れた効果が得られる。According to the method of the present invention, in the decarburization refining of chromium-containing molten steel, the decarburization efficiency can be improved, the amount of reducing Si added can be reduced, the decarburization rate can be improved, and the refining time can be shortened. Furthermore, excellent effects such as a reduction in the amount of slag and an improvement in component accuracy can be obtained overall.
【図１】本発明の実施態様例の説明図で、（ａ）は静止
状態、（ｂ）はガス吹込み状態を示す図。FIG. 1 is an explanatory diagram of an embodiment of the present invention, in which (a) shows a stationary state and (b) shows a gas blowing state.
【図２】本発明における脱炭酸素効率と（２１．３９［
％Ｓｉ］＋ＷＳ＋ＷＦ）／Ｌ／Ｌ０との関係を示す図。[Figure 2] Decarburization oxygen efficiency in the present invention and (21.39[
%Si]+WS+WF)/L/L0.
【図３】脱炭酸素効率と溶鋼中［Ｃ］濃度の関係を示す
図。FIG. 3 is a diagram showing the relationship between decarburization oxygen efficiency and [C] concentration in molten steel.
【図４】（ａ）は本発明実施例におけるガス吹込みパタ
ーンを示す図であり、（ｂ）は比較例のガス吹込みパタ
ーンを示す図。FIG. 4(a) is a diagram showing a gas blowing pattern in an example of the present invention, and FIG. 4(b) is a diagram showing a gas blowing pattern in a comparative example.
Claims (1)
溶鋼の浴面下および浴面上から酸素ガスを吹込むととも
に、浴面上に吹込んだ酸素ガスの火点部のスラグ量が下
記（１）式を満足する条件下で脱炭を行なうことを特徴
とする含クロム溶鋼の脱炭精錬法。 【数１】 但し ［％Ｓｉ］：炉内装入時の溶鋼中［Ｓｉ］濃度（ｗｔ％
） ＷＳ：単位溶鋼重量当りの持込みスラグ量（Ｋｇ／Ｔ）
ＷＦ：単位溶鋼重量当りの炉内装入後のフラックス添加
量（Ｋｇ／Ｔ） Ｌ／Ｌ０：上吹きガスによる浴面の凹み率Claim 1: Oxygen gas is blown from below and above the bath surface of chromium-containing molten steel containing 0.3% or more of carbon, and the amount of slag at the fire point of the oxygen gas blown onto the bath surface is reduced. A decarburization refining method for chromium-containing molten steel, characterized in that decarburization is performed under conditions that satisfy the following formula (1). [Equation 1] However, [%Si]: [Si] concentration in molten steel at the time of entering the furnace (wt%
) WS: Amount of slag brought in per unit weight of molten steel (Kg/T)
WF: Amount of flux added after loading into the furnace per unit weight of molten steel (Kg/T) L/L0: Concave rate of bath surface due to top-blown gas
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3729791A JPH04276009A (en) | 1991-03-04 | 1991-03-04 | Decarbonized refining method for chromium-containing molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3729791A JPH04276009A (en) | 1991-03-04 | 1991-03-04 | Decarbonized refining method for chromium-containing molten steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04276009A true JPH04276009A (en) | 1992-10-01 |
Family
ID=12493770
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3729791A Withdrawn JPH04276009A (en) | 1991-03-04 | 1991-03-04 | Decarbonized refining method for chromium-containing molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04276009A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008274315A (en) * | 2007-04-25 | 2008-11-13 | Nippon Steel Corp | Decarbonization refine method for chromium-based stainless steel |
-
1991
- 1991-03-04 JP JP3729791A patent/JPH04276009A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008274315A (en) * | 2007-04-25 | 2008-11-13 | Nippon Steel Corp | Decarbonization refine method for chromium-based stainless steel |
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