JPH0125369B2 - - Google Patents
Info
- Publication number
- JPH0125369B2 JPH0125369B2 JP57035145A JP3514582A JPH0125369B2 JP H0125369 B2 JPH0125369 B2 JP H0125369B2 JP 57035145 A JP57035145 A JP 57035145A JP 3514582 A JP3514582 A JP 3514582A JP H0125369 B2 JPH0125369 B2 JP H0125369B2
- Authority
- JP
- Japan
- Prior art keywords
- oxygen
- activity
- molten steel
- carbon
- vod
- 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
- 229910052760 oxygen Inorganic materials 0.000 claims description 32
- 239000001301 oxygen Substances 0.000 claims description 32
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 31
- 229910052799 carbon Inorganic materials 0.000 claims description 25
- 230000000694 effects Effects 0.000 claims description 20
- 229910000831 Steel Inorganic materials 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 18
- 239000010959 steel Substances 0.000 claims description 18
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 13
- 238000007664 blowing Methods 0.000 claims description 9
- 229910052804 chromium Inorganic materials 0.000 claims description 9
- 238000007670 refining Methods 0.000 claims description 8
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 7
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 238000003723 Smelting Methods 0.000 claims description 3
- 238000002474 experimental method Methods 0.000 claims 1
- 239000011651 chromium Substances 0.000 description 16
- 238000005261 decarburization Methods 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- 229910018540 Si C Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Description
【発明の詳細な説明】
この発明は含Cr溶鋼のVOD法における終点
〔Ｃ〕の制御方法に関し、終点〔Ｃ〕を適確にと
らえ効率の良い脱炭精錬を行うことを目的とす
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the end point [C] in the VOD method of Cr-containing molten steel, and an object thereof is to accurately determine the end point [C] and perform efficient decarburization refining.
VOD法は真空脱炭法としてステンレス鋼の製
造において広く普及している。このVOD法は取
鍋を真空槽内において取鍋底部より不活性ガスを
吹込むと共に取鍋上部よりO2吹錬を行うことよ
り脱炭精錬を行おうとするものである。 The VOD method is widely used in the production of stainless steel as a vacuum decarburization method. This VOD method attempts to perform decarburization refining by placing the ladle in a vacuum chamber, blowing inert gas from the bottom of the ladle, and blowing O2 from the top of the ladle.
従来このVOD法における終点〔Ｃ〕の判定は、
処理開始成分による計算酸素量による方法と排ガ
スの分析値による方法の両者を勘案して行つてい
た。しかしこの方法による判定は溶鋼温度や操業
真空度或いは送酸条件等の操業要因によつて大き
なバラツキがあり、終点〔Ｃ〕に適中率が低いた
め、実操業においては再送酸作業にならない様に
終点〔Ｃ〕を必要以上に吹下げて止めた後真空脱
炭作業を行つているのが現状である。しかしこの
場合、真空脱炭期のＣ―Ｏ反応による〔Ｃ〕によ
る酸化クロムの還元も〔Ｃ〕がないため少量にと
どまり、かつ〔Ｃ〕の吹下げによるCrの酸化ロ
スも多いため、これを回収する為の還元剤の使用
量を増加する必要があり、歩留が低下する問題が
あつた。また〔Ｃ〕を吹下げることに起因する精
錬時間の延長及び蒸気、酸素等の動力原単位の悪
化等の問題が生じていた。 Conventionally, the determination of the end point [C] in this VOD method is as follows:
The method was carried out by taking into consideration both a method based on the calculated oxygen amount based on the treatment starting components and a method based on the analyzed value of exhaust gas. However, the judgment made by this method has large variations depending on operational factors such as molten steel temperature, operating vacuum level, and oxygen feeding conditions, and the accuracy rate for the end point [C] is low, so in actual operation, it is necessary to avoid re-transferring oxygen. Currently, the vacuum decarburization work is performed after blowing down the end point [C] more than necessary and then stopping. However, in this case, the reduction of chromium oxide by [C] due to the C-O reaction during the vacuum decarburization stage is only a small amount because there is no [C], and there is also a large oxidation loss of Cr due to the blowing down of [C]. It was necessary to increase the amount of reducing agent used to recover the oxidants, which caused the problem of lower yields. In addition, problems such as an extension of the refining time and a deterioration of the power unit consumption of steam, oxygen, etc. due to the blowing down of [C] have occurred.
本発明は上記した従来技術の欠点を改善するた
めになされたもので、酸素メータにより溶鋼中の
酸素活量を測定すると共に、操業真空度より一酸
化炭素分圧を近似的に求め、更に送酸終了時点に
おける溶鋼中の主要成分の値をVOD開始時点の
値から求めてこれにより炭素活量を補正し、該酸
素活量、一酸化炭素分圧及び補正後の炭素活量か
ら溶鋼中の〔Ｃ〕を推定して終点〔Ｃ〕の制御を
行おうとするものである。 The present invention was made in order to improve the above-mentioned drawbacks of the prior art, and it measures the oxygen activity in molten steel with an oxygen meter, approximately determines the carbon monoxide partial pressure from the operating vacuum level, and further The values of the main components in the molten steel at the end of the acidification are calculated from the values at the start of VOD, and the carbon activity is corrected based on this, and the carbon activity in the molten steel is calculated from the oxygen activity, carbon monoxide partial pressure, and the corrected carbon activity. The purpose is to estimate [C] and control the end point [C].
以下本発明方法を図面に基づいて説明する。 The method of the present invention will be explained below based on the drawings.
第１図はVOD設備の正面図であり、１は取鍋、
２は真空槽、３はO2ランス、４はArガス等不活
性ガス吹込用の羽口、５は排気孔である。VOD
法ではO2ランス３からO2を吹込むと同時に羽口
４からArガス等不活性ガスを吹込んで脱炭精錬
を行うが、本発明方法においては送酸中又は酸素
停止後真空脱炭中に酸素メータ１０により溶鋼の
酸素活量aoを測定する。図に示す実施例では酸
素メータ１０の酸素センサ１１を取鍋１の上方か
ら昇降可能に設置し、該センサ１１を溶鋼中に浸
漬して測定する構成としている。 Figure 1 is a front view of the VOD equipment, where 1 is a ladle;
2 is a vacuum chamber, 3 is an O 2 lance, 4 is a tuyere for blowing inert gas such as Ar gas, and 5 is an exhaust hole. VOD
In the method, decarburization is carried out by injecting O 2 from the O 2 lance 3 and at the same time inert gas such as Ar gas from the tuyere 4. However, in the method of the present invention, decarburization is performed during oxygen supply or during vacuum decarburization after oxygen is stopped. The oxygen activity ao of the molten steel is measured using an oxygen meter 10. In the embodiment shown in the figure, the oxygen sensor 11 of the oxygen meter 10 is installed so as to be movable up and down from above the ladle 1, and the sensor 11 is immersed in molten steel for measurement.
この酸素活量aoから、一般的な下記Ｃ―Ｏ平
衡式を用いて〔％Ｃ〕を算出する。 From this oxygen activity ao, [%C] is calculated using the general CO equilibrium equation below.
logK（Pco／ac・ao）＝1160／Ｔ＋2.003……
上記式においてacは炭素活量、Pcoはco分
圧、またＫは平衡定数、Ｔは絶対温度である。 logK (Pco/ac・ao)=1160/T+2.003... In the above formula, ac is carbon activity, Pco is co partial pressure, K is equilibrium constant, and T is absolute temperature.
ここでPcoは操業真空度との関係において近似
的にP′co＝みかけのPcoとして求めることができ
る。即ち、見かけのPcoを、その精錬炉と精錬条
件によつて定まるところの操業真空度の関数とし
て求まる実験式を用いて、一酸化炭素分圧を近似
的に求める。このP′coと操業真空度との関係を
第２図に示す。またこのP′coと操業真空度との
回帰式は出願人の場合下記式の様になつた。 Here, Pco can be approximately determined as P′co=apparent Pco in relation to the operating vacuum degree. That is, the partial pressure of carbon monoxide is approximately determined using an empirical formula that determines the apparent Pco as a function of the operating vacuum determined by the refining furnace and refining conditions. The relationship between this P'co and the operating vacuum degree is shown in Figure 2. In the case of the applicant, the regression equation between P′co and the operating vacuum degree was as shown below.
P′co＝1.6×10-3×操業真空度＋0.012 ……
P′co＝みかけのPco（atm）
このP′coに影響を与える要因としては操業真
空度のみならず吹酸時のAr：O2比等があり、こ
れらによつても変化するものである。このため操
業条件によつてP′coを求める式及びフアクター
は変化する〔従つて上記の実験式は出願人の有
する精錬炉と精錬条件により定まつたものであ
り、これらの条件が異なれば、式そのものの形
（一次式、二次式、……等）や係数が異なること
になることは言うまでもない〕。 P'co=1.6×10 -3 ×Operating vacuum degree+0.012...P'co=Appearance Pco (atm) Factors that affect this P'co include not only the operating vacuum degree but also the Ar :O 2 ratio, etc., and it changes depending on these as well. For this reason, the formula and factor for determining P′co change depending on the operating conditions [Therefore, the above experimental formula was determined by the applicant's smelting furnace and refining conditions, and if these conditions differ, It goes without saying that the form of the equation itself (linear equation, quadratic equation, etc.) and coefficients will be different].
上記式により操業真空度からP′coを求める
ことができ、また酸素メーターによりaoが測定
できるから、式のＣ―Ｏ平衡式から〔％Ｃ〕を
求めることができる。 Since P'co can be determined from the operating vacuum level using the above formula, and ao can be measured using an oxygen meter, [%C] can be determined from the C--O equilibrium equation.
上記式にPco＝P′co，ac＝fc×〔％Ｃ〕を代
入して整理すると、
log〔％Ｃ〕＝logPco−logao−1160／Ｔ
−2.003−logfc ……
（相互作用助係数：eCr c＝−0.024，eNi c＝0.012，
eSi c＝0.106）が求まる。 Substituting Pco=P′co, ac=fc×[%C] into the above equation and rearranging it, log[%C]=logPco−logao−1160/T −2.003−logfc …… (interaction coefficient: e Cr c = −0.024, e Ni c = 0.012,
e Si c =0.106) is found.
ここで、fc：溶鋼中炭素の活量係数
又、溶鋼中炭素の活量acは溶鋼中のCr，Ni，
Si等（鋼種によりこの他にMn，Mo，Cu，Ｗの
１又は２以上の成分）の影響を受けることになる
ので、Cr，Ni，Si等の成分による上記のような
相互作用助係数を用いて次式のような要領でfcを
求めて炭素活量acを補正する。 Here, fc: Activity coefficient of carbon in molten steel. Also, the activity ac of carbon in molten steel is Cr, Ni,
Since it will be influenced by Si, etc. (and one or more of Mn, Mo, Cu, and W depending on the steel type), the interaction coefficients as mentioned above due to the components of Cr, Ni, Si, etc. Use the following formula to find fc and correct the carbon activity ac.
log fc＝eCr C〔％Cr〕＋eNi C〔％Ni〕
＋eSi C〔％Si〕
（上記他の成分の影響を考慮する場合は、
log fc＝eCr C〔％Cr〕＋eNi C〔％Ni〕
＋eSi C〔％Si〕＋eMn C〔％Mn〕
＋eMo C〔％Mo〕＋……）
但しeMn C＝−0.0084、eMo C＝−0.0137、
eW C＝−0.0056、eCu C＝0.016
尚、上記式の各係数は研究者によつて異な
るため、ここでは比較的信頼性の高いものと思わ
れているものを示した。 log fc=e Cr C [%Cr]+e Ni C [%Ni] +e Si C [%Si] (When considering the influence of other components mentioned above, log fc=e Cr C [%Cr]+e Ni C [%Ni] +e Si C [%Si] +e Mn C [%Mn] +e Mo C [%Mo] +……) However, e Mn C = −0.0084, e Mo C = −0.0137, e W C = −0.0056 , e Cu C = 0.016 Since each coefficient in the above formula differs depending on the researcher, we have shown what is considered to be relatively reliable here.
この式は相互作用助係数を用いて主要成分
（Cr，Ni，Si等）による〔Ｃ〕の活量に及ぼす影
響度を算定し、この〔Ｃ〕の活量を補正している
ため２％Crからオーステナイト系ステンレス鋼
に到る幅広い鋼種に適用できる特徴を持つてい
る。又式に代入する〔％Cr〕，〔％Ni〕，〔％Si〕
はVODスタート成分より経験式で求められる送
酸終了の推定値を用いることにより〔％Ｃ〕の推
定精度は向上する。この様にして求めた計算〔％
Ｃ〕値と実績〔％Ｃ〕値の関係を第３図に示す。
第３図から明らかな様に±0.01％以下の精度で
〔％Ｃ〕を推定することができ、かつ２％Cr鋼、
13％Cr鋼及びステンレス鋼に幅広く摘要できる
ことがわかる。 This formula calculates the degree of influence of the main components (Cr, Ni, Si, etc.) on the activity of [C] using interaction coefficients, and corrects the activity of [C] by 2%. It has characteristics that allow it to be applied to a wide range of steel types, from Cr to austenitic stainless steel. Also substitute [%Cr], [%Ni], [%Si] into the formula
The accuracy of estimating [%C] can be improved by using the estimated value of the end of oxygen delivery determined by an empirical formula from the VOD start component. Calculation obtained in this way [%
Figure 3 shows the relationship between the C] value and the actual [%C] value.
As is clear from Figure 3, [%C] can be estimated with an accuracy of ±0.01% or less, and 2% Cr steel,
It can be seen that this can be broadly applied to 13% Cr steel and stainless steel.
VOD送酸終了の〔％Ｃ〕とCrの酸化ロス量の
関係を第４図に示す。従来方法に於ては、送酸終
了〔％Ｃ〕適中精度が悪いためSUS304を溶製す
る時に於ても〔Ｃ〕を0.04％以下まで吹下げてCr
酸化ロス量も1.2％に達していたが、本発明によ
るVOD脱炭途中での酸素メーター使用により途
中〔％Ｃ〕を推定し、その後の酸素量、脱炭量を
経験式で計算することにより〔Ｃ〕の適中精度が
著しく向上し適正〔％Ｃ〕値で吹止めることが可
能となり諸原単位の向上及び歩留の向上に大きく
寄与した。 Figure 4 shows the relationship between [%C] at the end of VOD oxygen supply and the amount of Cr oxidation loss. In the conventional method, the accuracy in determining the end of oxygen supply [%C] is poor, so even when melting SUS304, [C] is blown down to 0.04% or less .
The amount of oxidation loss also reached 1.2%, but by using an oxygen meter during VOD decarburization according to the present invention to estimate [%C] midway, and calculating the subsequent oxygen amount and decarburization amount using an empirical formula. The accuracy of hitting [C] was significantly improved, making it possible to stop blowing at an appropriate [%C] value, which greatly contributed to improving various basic units and yield.
以上説明したように本発明方法では酸素メータ
により溶鋼中の酸素活量を測定すると共に、操業
真空度より一酸化炭素分圧を近似的に求め、更に
送酸終了時点における溶鋼中の主要成分の値を
VOD開始時点の値から求めてこれにより炭素活
量を補正し、該酸素活量、一酸化炭素分圧及び補
正後の炭素活量から溶鋼中の炭素量を推定するよ
うにしているため炭素量の適中率が高く適正な
〔％Ｃ〕値で吹止めることが可能となり、諸原単
位の向上及び歩留の向上を図ることが可能とな
る。 As explained above, in the method of the present invention, the oxygen activity in molten steel is measured using an oxygen meter, the carbon monoxide partial pressure is approximately determined from the operating vacuum level, and the main components in molten steel at the end of oxygen feeding are measured. The value
The carbon content is calculated from the value at the start of VOD and corrected accordingly, and the amount of carbon in molten steel is estimated from the oxygen activity, carbon monoxide partial pressure, and the corrected carbon activity. It is possible to stop blowing at an appropriate [%C] value with a high accuracy rate, and it is possible to improve various basic units and yield.
第１図は本発明方法を説明するためのVOD設
備の正面図、第２図はVOD脱炭精錬期の操業真
空度とみかけPcoの関係を示すグラフ、第３図は
本発明方法による計算〔Ｃ〕と実績〔Ｃ〕との関
係を示すグラフ、第４図はVOD送酸終了〔Ｃ〕
とCr酸化ロス量との関係を示すグラフである。
１……取鍋、２……真空槽、３……O2ランス、
４……羽口、５……排気孔、１０……酸素メー
タ、１１……酸素センサ。
Figure 1 is a front view of the VOD equipment for explaining the method of the present invention, Figure 2 is a graph showing the relationship between the operating vacuum level and apparent Pco during the VOD decarburization refining stage, and Figure 3 is the calculation using the method of the present invention. A graph showing the relationship between [C] and actual performance [C], Figure 4 shows the end of VOD oxygen supply [C]
FIG. 3 is a graph showing the relationship between the amount of oxidation loss and the amount of Cr oxidation loss. 1...Ladle, 2...Vacuum chamber, 3... O2 lance,
4...Tuyere, 5...Exhaust hole, 10...Oxygen meter, 11...Oxygen sensor.
Claims (1)
の酸素活量を測定すると共に、精錬炉と精錬条件
によつて定まるところの操業真空度の関数として
見かけのPcoの求められる実験式を用いて一酸化
炭素分圧を近似的に求め、且つ送酸終了時点にお
ける溶鋼中のCr，Ni，Si等の値をVOD開始時点
の値から求めてこれらの値により炭素活量を補正
し、前記酸素活量、一酸化炭素分圧及び補正後の
炭素活量から所定のＣ―Ｏ平衡式に基づいて溶鋼
中の炭素量を推定し、更に該推定値により送酸す
べき酸素量を決定して脱炭精錬することを特徴と
する含Cr溶鋼のVOD法における終点〔Ｃ〕の制
御方法。[Claims] 1. An experiment in which the oxygen activity in molten steel is measured using an oxygen meter during blowing, and the apparent Pco is determined as a function of the operating vacuum determined by the smelting furnace and smelting conditions. Approximately calculate the carbon monoxide partial pressure using the formula, calculate the values of Cr, Ni, Si, etc. in the molten steel at the end of oxygen supply from the values at the start of VOD, and correct the carbon activity using these values. Then, the amount of carbon in the molten steel is estimated from the oxygen activity, carbon monoxide partial pressure, and corrected carbon activity based on a predetermined C-O balance equation, and the amount of oxygen to be supplied is determined based on the estimated value. A method for controlling the end point [C] in the VOD method of Cr-containing molten steel, which is characterized by determining and decarburizing refining.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3514582A JPS58153721A (en) | 1982-03-08 | 1982-03-08 | Controlling method of end carbon content in vod process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3514582A JPS58153721A (en) | 1982-03-08 | 1982-03-08 | Controlling method of end carbon content in vod process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58153721A JPS58153721A (en) | 1983-09-12 |
| JPH0125369B2 true JPH0125369B2 (en) | 1989-05-17 |
Family
ID=12433733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3514582A Granted JPS58153721A (en) | 1982-03-08 | 1982-03-08 | Controlling method of end carbon content in vod process |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58153721A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06244584A (en) * | 1993-02-17 | 1994-09-02 | Nec Corp | Shielding mechanism for printed board |
| JP2586389B2 (en) * | 1993-09-17 | 1997-02-26 | 日本電気株式会社 | LSI case shield structure |
| JPH07147495A (en) * | 1993-11-26 | 1995-06-06 | Nec Corp | Printed board surface mounting shield case |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4875412A (en) * | 1972-01-14 | 1973-10-11 | ||
| JPS4875410A (en) * | 1972-01-14 | 1973-10-11 |
-
1982
- 1982-03-08 JP JP3514582A patent/JPS58153721A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4875412A (en) * | 1972-01-14 | 1973-10-11 | ||
| JPS4875410A (en) * | 1972-01-14 | 1973-10-11 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58153721A (en) | 1983-09-12 |
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