JPH11350018A - Method for estimating carbon concentration and refining method - Google Patents
Method for estimating carbon concentration and refining methodInfo
- Publication number
- JPH11350018A JPH11350018A JP15313298A JP15313298A JPH11350018A JP H11350018 A JPH11350018 A JP H11350018A JP 15313298 A JP15313298 A JP 15313298A JP 15313298 A JP15313298 A JP 15313298A JP H11350018 A JPH11350018 A JP H11350018A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- carbon concentration
- estimated
- carbon
- temperature
- 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
Abstract
Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【発明の属する技術分野】本発明はＣｒ含有鋼精錬中の
炭素濃度推定方法であり、これを用いて精錬を行う方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for estimating carbon concentration during refining of Cr-containing steel, and to a method for refining using the same.
【０００２】[0002]
【従来の技術】Ｃｒ含有鋼の精錬方法には、減圧下で酸
素の吹き込みを行い、吹き込みを停止した後、不活性ガ
スの中で精錬中の溶鋼を攪拌することで脱炭、脱酸を行
うＶＯＤプロセス及び大気圧下で酸素を含む不活性ガス
の吹き込みを行ったあと、不活性ガスの中で精錬中の溶
鋼を攪拌することで脱炭、脱酸を行うＡＯＤプロセスな
どがある。2. Description of the Related Art In a method of refining Cr-containing steel, oxygen is blown under reduced pressure, the blowing is stopped, and then the molten steel being refined is stirred in an inert gas to remove decarburization and deoxidation. There are a VOD process to be performed and an AOD process to perform decarburization and deoxidation by stirring molten steel being refined in an inert gas after blowing an inert gas containing oxygen under atmospheric pressure.
【０００３】何れも、炭素が酸化してできるＣＯガス分
圧を低下させて溶鋼中に多量に含まれるＣｒの酸化損失
を抑えつつ、極低炭素ステンレス鋼及び高純度ステンレ
ス鋼など高品質、高性能ステンレス鋼の生産を可能にす
るＣｒ含有鋼の精錬方法である。[0003] In any case, while reducing the partial pressure of CO gas formed by oxidizing carbon to suppress the oxidative loss of Cr contained in a large amount in molten steel, high quality, high quality stainless steel such as ultra-low carbon stainless steel and high purity stainless steel are used. This is a method for refining Cr-containing steel that enables the production of high performance stainless steel.
【０００４】Ｃｒ含有鋼の精錬中においてとりわけ重要
なことは、酸素の吹き込みを停止した時点における溶鋼
中の炭素量を正確に把握することである。なぜなら、脱
炭未達の場合は再精錬実施による処理時間の延長を招
き、一方過剰脱炭の場合はＣｒの酸化損失が増加し、こ
れを還元回収するために還元剤の使用を余儀なくさせる
ために製鋼コストが増大してしまうからである。It is particularly important during the refining of Cr-containing steel to accurately determine the amount of carbon in the molten steel at the time when oxygen blowing is stopped. This is because, if the decarburization has not been achieved, the treatment time is extended by performing refining.On the other hand, if the decarburization is excessive, the oxidation loss of Cr increases, and the use of a reducing agent is required to reduce and recover this. This is because steelmaking costs increase.
【０００５】そこで従来より、Ｃｒ含有鋼の精錬におい
て溶鋼中の炭素量を推定し、調節する方法が提案されて
きた。特開昭５１−８１７２２号公報では、減圧下にお
けるＣｒ含有鋼の精錬において、真空容器へ侵入する空
気のリーク量がほぼ一定であること、また、排気ガス中
のＣＯ2 吸収率は一定条件で循環するスチームジェット
中においてほぼ一定であることに着目し、真空容器に侵
入する空気及び排気ガス中の炭素量、または、採取した
溶鋼から求めた炭素量を用いて脱炭速度及び脱炭量を経
時的に求めて、これらが予め定めた時間的推移に追従す
るように酸素供給量、真空度及び環流量などの操業条件
を変更しながら精錬を行う方法が示されている。[0005] Therefore, a method of estimating and adjusting the amount of carbon in molten steel in the refining of Cr-containing steel has conventionally been proposed. Japanese Patent Application Laid-Open No. 51-81722 discloses that in refining Cr-containing steel under reduced pressure, the amount of air leaking into a vacuum vessel is almost constant, and the CO 2 absorption rate in exhaust gas is constant. Focusing on the fact that it is almost constant in the circulating steam jet, the decarburization rate and the decarburization amount are determined using the carbon amount in the air and exhaust gas entering the vacuum vessel or the carbon amount obtained from the sampled molten steel. A method is described in which refining is performed over time and the operating conditions such as the oxygen supply amount, the degree of vacuum, and the annular flow rate are changed so that they follow a predetermined time course.
【０００６】しかし、上述の方法では、操業条件の変更
を頻繁に行うために、精錬が終了した時点において溶鋼
成分の適中率が低下することがあった。However, in the above-mentioned method, since the operating conditions are frequently changed, the appropriate ratio of the molten steel component may be lowered at the time when the refining is completed.
【０００７】そこで、特開昭６１−１９７２６号公報に
は、予め所定時間内に溶鋼中の炭素量が目標値になるよ
うに、予め精錬目標時間、添加剤の添加タイミング、及
び真空度など操業条件を設定して精錬を開始し、精錬中
の任意の時点で溶鋼中の炭素量及びその他の成分並びに
温度を把握して精錬終了時の炭素量を予測し、目標値と
の差が零となるように溶鋼中の物質移動律速における反
応速度に基づくモデル式により脱炭及び加炭を行って精
錬を行う方法が示されている。Therefore, Japanese Unexamined Patent Publication (Kokai) No. 61-19726 discloses an operation such as a refining target time, an additive addition timing, and a degree of vacuum so that the amount of carbon in molten steel reaches a target value within a predetermined time. Set refining conditions and start refining.At any time during refining, grasp the amount of carbon in molten steel and other components and temperature, predict the amount of carbon at the end of refining, and determine that the difference from the target value is zero. Thus, a method of performing refining by performing decarburization and carburization by a model formula based on a reaction rate in mass transfer control in molten steel is shown.
【０００８】また、特開平８−４１５２８号公報では、
精錬中の任意の時点において溶鋼を採取し炭素量の測定
を行った後、排出ガスの流量及び成分により溶鋼中の炭
素量の推定値を所定の時間が経過するごとに求め、それ
が１００ｐｐｍから３０ｐｐｍとなる任意の時点で、渡
辺らが ＣＡＭＰ−｜Ｓ｜−Ｊ Ｖｏｌ，１（１９８
８）−２３４で紹介した溶鋼表面の気液界面で進行する
脱炭速度と気液界面を介さずに進行する炭素と酸素の脱
炭速度とを表す微分式を用いて溶鋼中の炭素量の推移を
推定する方法を採用して精錬を行うという方法が示され
ている。In Japanese Patent Application Laid-Open No. 8-41528,
After collecting molten steel at any time during refining and measuring the amount of carbon, an estimated value of the amount of carbon in the molten steel is obtained every time a predetermined time elapses from the flow rate and composition of the exhaust gas, and it is calculated from 100 ppm. At an arbitrary time point of 30 ppm, Watanabe et al. Reported that CAMP- | S | -J Vol, 1 (198
8) The amount of carbon in the molten steel is calculated by using a differential equation representing the decarburization rate at the gas-liquid interface of the molten steel surface and the decarburization rate of carbon and oxygen that does not pass through the gas-liquid interface introduced at -234. A method of performing refining by adopting a method of estimating a transition is shown.
【０００９】[0009]
【発明が解決しようとする課題】しかしながら特開昭５
１−８１７２２号公報の方法では、予め設定した脱炭速
度及び脱炭量と照合すべき脱炭速度及び脱炭量をより正
確に算出するために採取した溶鋼から求めた炭素量を用
いる必要があった。However, Japanese Unexamined Patent Publication No.
In the method of 1-81722, it is necessary to use the carbon amount obtained from the molten steel collected in order to more accurately calculate the decarburization speed and the decarburization amount to be compared with the preset decarburization speed and the decarburization amount. there were.
【００１０】また特開昭６１−１９７２６号公報の方法
では、精錬終了時の炭素量は精錬中の所定の時点におい
て把握される溶鋼中の炭素量に基づいて求められるため
に、正確さを期するうえで実測による炭素量を用いるこ
とが考えられる。In the method disclosed in Japanese Patent Application Laid-Open No. 61-19726, the amount of carbon at the end of refining is determined on the basis of the amount of carbon in molten steel obtained at a predetermined time during refining. In doing so, it is conceivable to use the measured amount of carbon.
【００１１】さらに特開平８−４１５２８号公報の方法
では、精錬の途中から溶鋼中の炭素量の推定値を求めて
ゆく場合、溶鋼のサンプリングを行うとしており、この
ように溶鋼中の炭素量の実測は、いずれの場合にでも最
善を期するために必然になされることから、精錬時間の
延長及び精錬コストの増大を招く原因となっていた。Further, in the method disclosed in Japanese Patent Application Laid-Open No. 8-41528, when the estimated value of the amount of carbon in molten steel is obtained during refining, sampling of molten steel is performed. In any case, since the actual measurement is necessarily performed in order to make the best possible, the refining time is extended and the refining cost is increased.
【００１２】本発明はかかる事情に鑑みてなされたもの
であり、Ｃｒ含有鋼の精錬において、酸素の吹き込みを
停止した時点で、推定した溶鋼中のＣｒ、Ｎｉ濃度及び
溶鋼温度とＣＯガス分圧とで求められる平衡到達炭素濃
度と比較することにより、溶鋼中の炭素濃度の推定値が
精度の良いものかどうか溶鋼のサンプリングを行うこと
なく判定でき、また精度が悪くても溶鋼温度を測定する
だけで溶鋼中の炭素濃度の推定値を補正できることによ
り、溶鋼中の炭素濃度を高精度に推定する方法及びこれ
により過剰脱炭を防ぎ、Ｃｒ酸化損失を抑制できるよう
に精錬を制御する方法を提供することにある。The present invention has been made in view of such circumstances, and in the refining of a Cr-containing steel, when the oxygen blowing is stopped, the estimated Cr and Ni concentrations in the molten steel, the molten steel temperature, and the CO gas partial pressure. By comparing with the equilibrium-attained carbon concentration obtained by the above, it is possible to determine whether the estimated value of the carbon concentration in the molten steel is accurate or not without sampling the molten steel, and to measure the molten steel temperature even if the accuracy is poor. A method for accurately estimating the carbon concentration in molten steel by being able to correct the estimated value of the carbon concentration in molten steel alone and a method for controlling refining so as to prevent excessive decarburization and suppress Cr oxidation loss by this To provide.
【００１３】[0013]
【課題を解決するための手段】第１発明に係る炭素濃度
推定方法は、酸素の吹き込みを開始した後、排出ガスの
流量及び組成を測定して物質収支より溶鋼中の炭素、Ｃ
ｒ及びＮｉの濃度を推定し、酸素の吹き込みを停止した
後、推定したＣｒ及びＮｉの濃度と、溶鋼温度と、減圧
真空度から求めたＣＯガス分圧とを用いて平衡到達炭素
濃度を求め、求めた平衡到達炭素濃度と推定した溶鋼中
の炭素濃度との差から溶鋼中炭素量補正値を求め、爾
後、求めた溶鋼中炭素量補正値を用いて溶鋼中の炭素濃
度を推定することを特徴とする。The carbon concentration estimating method according to the first aspect of the present invention is to measure the flow rate and the composition of the exhaust gas after starting the blowing of oxygen, and measure the carbon and C in the molten steel from the material balance.
After estimating the concentrations of r and Ni, and stopping the blowing of oxygen, the equilibrium carbon concentration was determined using the estimated concentrations of Cr and Ni, the temperature of the molten steel, and the partial pressure of CO gas determined from the degree of vacuum under reduced pressure. Calculating the corrected carbon content in the molten steel from the difference between the calculated equilibrium carbon concentration and the estimated carbon concentration in the molten steel, and then estimating the carbon concentration in the molten steel using the obtained corrected carbon content in the molten steel. It is characterized by.
【００１４】第２発明に係る炭素濃度推定方法は、酸素
の吹き込みを開始した後、熱収支より溶鋼温度を推定
し、酸素の吹き込みを停止した後、推定した溶鋼温度を
用いて平衡到達炭素濃度を求め、求めた平衡到達炭素濃
度と前記溶鋼中の炭素濃度との差が所定の範囲外にある
場合、溶鋼温度を測定し、測定した溶鋼温度と推定した
溶鋼温度との差から溶鋼温度補正値を求め、求めた溶鋼
温度補正値を用いて平衡到達炭素濃度を算出し、算出し
た平衡到達炭素濃度と前記溶鋼中の炭素濃度との差から
溶鋼中炭素量補正値を求め、爾後、求めた溶鋼温度補正
値及び溶鋼中炭素量補正値を用いて溶鋼温度及び溶鋼中
の炭素濃度を推定することを特徴とする。In the carbon concentration estimating method according to the second aspect of the present invention, after injecting oxygen, the temperature of the molten steel is estimated from the heat balance, the injecting of oxygen is stopped, and the carbon concentration attained equilibrium is estimated using the estimated temperature of the molten steel. If the difference between the obtained carbon concentration in equilibrium and the carbon concentration in the molten steel is out of the predetermined range, the molten steel temperature is measured, and the molten steel temperature is corrected from the difference between the measured molten steel temperature and the estimated molten steel temperature. The carbon concentration in the molten steel is calculated from the difference between the calculated carbon concentration in the equilibrium and the carbon concentration in the molten steel, and the corrected carbon content in the molten steel is calculated. The molten steel temperature and the carbon concentration in the molten steel are estimated using the molten steel temperature correction value and the carbon content correction value in the molten steel.
【００１５】第３発明に係る炭素濃度推定方法は、前記
求めた平衡到達炭素濃度と前記溶鋼中の炭素濃度との差
が所定の範囲内にある場合、溶鋼中の炭素濃度の推定が
妥当であると判定し、引き続き溶鋼温度及び溶鋼中の炭
素濃度を推定することを特徴とする。[0015] In the carbon concentration estimating method according to the third invention, the estimation of the carbon concentration in the molten steel is appropriate if the difference between the obtained equilibrium carbon concentration and the carbon concentration in the molten steel is within a predetermined range. It is characterized by determining that there is, and subsequently estimating the molten steel temperature and the carbon concentration in the molten steel.
【００１６】第４発明に係る精錬方法は、酸素の吹き込
みを開始した後、排出ガスの流量及び組成を測定して物
質収支より溶鋼中の炭素濃度を推定し、Ａｌ、Ｓｉ及び
Ｍｎの酸化量の推定をして溶鋼中のＣｒ及びＮｉの濃度
を推定し、また熱収支から溶鋼温度を推定し、酸素の吹
き込みを停止した後、推定したＣｒ、Ｎｉの濃度及び溶
鋼温度と、測定した減圧真空度から求めたＣＯガス分圧
とを用いて平衡到達炭素濃度を求め、求めた平衡到達炭
素濃度と推定した前記溶鋼中の炭素濃度との差を求めて
得た値が所定の範囲内にある場合、溶鋼中の炭素濃度の
推定が妥当であると判定し、引き続き推定した溶鋼温度
及び溶鋼中の炭素濃度を元にして精錬を行い、前記平衡
到達炭素濃度と前記溶鋼中の炭素濃度との差が所定の範
囲外にある場合、溶鋼温度を測定し、測定した溶鋼温度
と推定した溶鋼温度との差から溶鋼温度補正値を求め、
溶鋼温度補正値を用いて平衡到達炭素濃度を算出し、算
出した平衡到達炭素濃度と前記溶鋼中の炭素濃度との差
から溶鋼中炭素量補正値を求めて、爾後、求めた溶鋼温
度補正値及び溶鋼中炭素量補正値を用いて推定した溶鋼
温度及び溶鋼中の炭素濃度を元にして精錬を行うことを
特徴とする。In the refining method according to the fourth aspect of the present invention, after injecting oxygen, the flow rate and composition of the exhaust gas are measured to estimate the carbon concentration in the molten steel from the material balance, and the oxidation amounts of Al, Si and Mn are determined. After estimating the concentrations of Cr and Ni in the molten steel, and estimating the temperature of the molten steel from the heat balance, and stopping the blowing of oxygen, the estimated concentrations of Cr and Ni and the molten steel temperature, and the measured pressure reduction The equilibrium carbon concentration is determined using the CO gas partial pressure determined from the degree of vacuum, and the value obtained by calculating the difference between the determined equilibrium carbon concentration and the estimated carbon concentration in the molten steel is within a predetermined range. In some cases, it is determined that the estimation of the carbon concentration in the molten steel is appropriate, and then refining is performed based on the estimated molten steel temperature and the carbon concentration in the molten steel, and the equilibrium carbon concentration and the carbon concentration in the molten steel are determined. If the difference is out of the predetermined range, The steel temperature was measured to obtain the molten steel temperature correction value from the difference between the measured molten steel temperature estimated molten steel temperature,
Using the molten steel temperature correction value to calculate the equilibrium carbon concentration, obtaining the carbon content correction value in the molten steel from the difference between the calculated equilibrium carbon concentration and the carbon concentration in the molten steel, and thereafter, the obtained molten steel temperature correction value And refining is performed based on the molten steel temperature and the carbon concentration in the molten steel estimated using the correction value of the carbon content in the molten steel.
【００１７】本発明者はＣｒ含有鋼の精錬中、酸素の吹
き込みを停止した後、溶鋼をサンプリングして得た溶鋼
中のＣｒ及びＮｉの濃度並びに溶鋼温度の測定値とＣＯ
ガス分圧とを用いて平衡到達炭素濃度を求めたところ、
溶鋼中の炭素濃度の測定値と近似することを知見した。The inventor of the present invention stopped the oxygen blowing during the refining of the Cr-containing steel, and then measured the Cr and Ni concentrations and the molten steel temperature in the molten steel obtained by sampling the molten steel.
When the equilibrium carbon concentration was determined using the gas partial pressure and
It was found that it was close to the measured value of carbon concentration in molten steel.
【００１８】また脱炭と並行して、溶鋼中のＡｌ、Ｓ
ｉ、Ｍｎ及びＣｒの酸化が生じていることに着目し、酸
素の吹き込みを開始したときから溶鋼中のＣｒ及びＮｉ
の濃度並びに溶鋼温度の推定値を求め、測定値とさしか
えて平衡到達炭素濃度を求めたところ、炭素濃度の推定
精度が良好であるかどうか判定するには何ら問題がない
ことを知見した。これにより、溶鋼中の炭素濃度を溶鋼
のサンプリングを行うことなく高精度に推定することが
可能となった。In parallel with the decarburization, Al, S
Focusing on the oxidation of i, Mn, and Cr, Cr and Ni in the molten steel from the start of oxygen blowing.
When the estimated carbon concentration and the molten steel temperature were calculated and the equilibrium carbon concentration was calculated in place of the measured values, it was found that there was no problem in determining whether the estimation accuracy of the carbon concentration was good. As a result, the carbon concentration in the molten steel can be estimated with high accuracy without sampling the molten steel.
【００１９】また溶鋼中の炭素濃度の推定精度が悪くな
った場合には、このときの溶鋼温度を測定して溶鋼温度
補正値を得、そして温度のみを測定値と差し替えた平衡
到達炭素濃度を求めて炭素量補正値を得ることによって
溶鋼中の炭素濃度値を補正できることから、ひきつづき
溶鋼中の炭素濃度を溶鋼のサンプリングを行うことなく
精度良く推定することが可能となった。If the accuracy of estimating the carbon concentration in the molten steel deteriorates, the molten steel temperature at this time is measured to obtain a molten steel temperature correction value, and the equilibrium carbon concentration obtained by replacing only the temperature with the measured value is calculated. Since the carbon concentration value in the molten steel can be corrected by obtaining the corrected carbon content value, it has become possible to accurately estimate the carbon concentration in the molten steel without sampling the molten steel.
【００２０】こうして推定した溶鋼中の炭素濃度をもと
に、Ｃｒ含有鋼の精錬を行うことによって従来必要とさ
れていた溶鋼のサンプリング及び精錬時間の延長を解消
できるうえに過剰脱炭を防止し、Ｃｒの酸化損失を抑制
することを可能にした。By refining the Cr-containing steel based on the carbon concentration in the molten steel estimated in this way, it is possible to eliminate the conventionally required time required for sampling and refining of the molten steel and to prevent excessive decarburization. , Cr oxidation loss can be suppressed.
【００２１】以下に溶鋼中の炭素濃度の推定値及び平衡
到達炭素濃度の計算手順を説明する。 (1) 溶鋼中の炭素濃度の推定値の求め方 まず排出ガスの流量及び組成を測定し、排出ガス中の炭
素量を求める。The procedure for estimating the carbon concentration in the molten steel and calculating the equilibrium carbon concentration will be described below. (1) How to calculate the estimated value of the carbon concentration in the molten steel First, measure the flow rate and composition of the exhaust gas to determine the carbon content in the exhaust gas.
【００２２】[0022]
【数１】 (Equation 1)
【００２３】これにより溶鋼中の炭素濃度の推定値は下
記(2) の式を用いて求めることができる。Thus, the estimated value of the carbon concentration in the molten steel can be obtained by using the following equation (2).
【００２４】[0024]
【数２】 (Equation 2)
【００２５】(2) 平衡到達炭素濃度の求め方 １．溶鋼中のＣｒ及びＮｉ濃度の推定値の求め方 まず溶鋼中のＡｌ，Ｓｉ及びＭｎの酸化量を下記(3)
(4) (5) 式より求める。(2) How to Obtain Equilibrium Carbon Concentration How to obtain the estimated values of Cr and Ni concentrations in molten steel First, the oxidation amounts of Al, Si and Mn in molten steel are shown in (3)
(4) Obtained from equation (5).
【００２６】[0026]
【数３】 (Equation 3)
【００２７】吹き込みガスの流量と排出ガスの流量及び
組成とを測定して、吹き込みガス及び排出ガスの酸素量
を下記(6) (7) 式より求める。The flow rate of the blown gas and the flow rate and the composition of the exhaust gas are measured, and the oxygen amounts of the blown gas and the exhaust gas are determined by the following equations (6) and (7).
【００２８】[0028]
【数４】 (Equation 4)
【００２９】排出ガス中の炭素量を下記(8) 式より求め
る。The amount of carbon in the exhaust gas is determined by the following equation (8).
【００３０】[0030]
【数５】 (Equation 5)
【００３１】これよりＣｒの酸化量を下記(9) 式より求
める。From this, the oxidation amount of Cr is determined by the following equation (9).
【００３２】[0032]
【数６】 (Equation 6)
【００３３】こうして溶鋼中のＣｒの濃度の推定値は下
記(10)式により求めることができる。Thus, the estimated value of the Cr concentration in the molten steel can be obtained by the following equation (10).
【００３４】[0034]
【数７】 (Equation 7)
【００３５】一方、溶鋼中のＮｉの濃度の推定値は下記
(11)式により求めることができる。On the other hand, the estimated value of the concentration of Ni in the molten steel is as follows.
It can be obtained by equation (11).
【００３６】[0036]
【数８】 (Equation 8)
【００３７】２．溶鋼温度の求め方 まず排出ガスの流量と組成を測定し、排出ガス量、排出
ガス中に含まれるＣＯ量、及びＣＯ2 量を下記(12)(13)
(14)式より求める。2. How to determine the temperature of molten steel First, measure the flow rate and composition of the exhaust gas, and determine the amount of exhaust gas, the amount of CO contained in the exhaust gas, and the amount of CO 2 as follows (12) (13)
It is calculated from equation (14).
【００３８】[0038]
【数９】 (Equation 9)
【００３９】下記(15)(16)式より溶鋼中における熱収支
を求める。The heat balance in the molten steel is obtained from the following equations (15) and (16).
【００４０】[0040]
【数１０】 (Equation 10)
【００４１】これより溶鋼温度を下記(17)式より求める
ことができる。From this, the temperature of the molten steel can be obtained from the following equation (17).
【００４２】[0042]
【数１１】 [Equation 11]
【００４３】３．平衡到達炭素濃度の求め方 こうして求めた溶鋼中のＣｒ、Ｎｉ濃度及び溶鋼温度の
推定値を用いて、下記(18)式より平衡到達炭素濃度を求
めることができる。3. Using the estimated values of the Cr and Ni concentrations and the molten steel temperature in the molten steel thus obtained, the equilibrium carbon concentration can be determined from the following equation (18).
【００４４】[0044]
【数１２】 (Equation 12)
【００４５】溶鋼中の炭素濃度の推定精度は、酸素の吹
き込みを停止した時点で、前述の計算手順に従って求め
た平衡到達炭素濃度と溶鋼中の炭素濃度の推定値とで差
を求め、これが所定の範囲内にあった場合において良好
であると言える。The accuracy of estimating the carbon concentration in the molten steel is determined by calculating the difference between the equilibrium carbon concentration obtained according to the above-described calculation procedure and the estimated carbon concentration in the molten steel at the time of stopping the blowing of oxygen. It can be said that it is good when it is within the range of.
【００４６】平衡到達炭素濃度の指針としての信頼性の
高さは、図３において溶鋼中の炭素濃度の実測値とほぼ
一致していることから明白である。従って平衡到達炭素
濃度と溶鋼中の炭素濃度の推定値との差が所定の範囲を
超える値になった場合、推定精度は悪くなったと言え
る。このようなときには、まず溶鋼温度を測定して溶鋼
温度補正値を下記(19)式より求める。The high level of reliability as a guide to the equilibrium carbon concentration is evident from FIG. 3 because it substantially matches the measured carbon concentration in the molten steel. Therefore, when the difference between the equilibrium-achieved carbon concentration and the estimated value of the carbon concentration in the molten steel exceeds a predetermined range, it can be said that the estimation accuracy has deteriorated. In such a case, first, the molten steel temperature is measured, and a molten steel temperature correction value is obtained from the following equation (19).
【００４７】[0047]
【数１３】 (Equation 13)
【００４８】溶鋼温度補正値を用いて溶鋼温度の推定値
を補正し、平衡到達炭素濃度を求める。Using the molten steel temperature correction value, the estimated value of the molten steel temperature is corrected, and the equilibrium carbon concentration is obtained.
【００４９】次に、溶鋼中炭素量補正値を下記(20)式か
ら求める。Next, a correction value of the carbon content in the molten steel is obtained from the following equation (20).
【数１４】 [Equation 14]
【００５０】爾後、溶鋼中の炭素量補正値を用いて溶鋼
中の炭素濃度を推定する。Thereafter, the carbon concentration in the molten steel is estimated using the carbon amount correction value in the molten steel.
【００５１】酸素の吹き込みを停止した時点で求めた平
均到達炭素濃度を指針にすることにより溶鋼中の炭素濃
度の推定精度が良好であるか否か判定でき、悪い場合に
は溶鋼温度を測定するだけで溶鋼中の炭素濃度を補正で
きるために、溶鋼中の炭素濃度の推定を精度良く行うこ
とが可能である。そしてこの溶鋼中の炭素濃度の推定値
をもとにして精錬を行うことにより、過剰脱炭を防止
し、Ｃｒの酸化損失を抑制することが可能となる。Using the average attained carbon concentration obtained at the time of stopping the oxygen blowing as a guide, it is possible to judge whether or not the accuracy of estimating the carbon concentration in the molten steel is good, and if not, measure the temperature of the molten steel. Since the carbon concentration in the molten steel can be corrected only by the above, it is possible to accurately estimate the carbon concentration in the molten steel. By performing refining based on the estimated value of the carbon concentration in the molten steel, excessive decarburization can be prevented, and oxidation loss of Cr can be suppressed.
【００５２】[0052]
【発明の実施の形態】以下本発明をその実施例を示す図
面に基づいて詳述する。図１は本発明におけるＣｒ含有
鋼の精錬制御装置の構成を示すブロック図である。プロ
セスコンピュータ１から精錬開始前の溶鋼量、組成、及
び温度並びに投入する合金鉄量、媒溶剤量及び合金鉄組
成の設定値を読み込み、吹き込みガスの流量、排出ガス
の流量及び組成並びに減圧真空度を測定装置２１，２
２，２３から取り込む。制御装置３はこれらの設定値及
び測定値を用いて溶鋼中の炭素濃度及びＣｒの濃度、Ｎ
ｉの濃度並びに溶鋼温度の推定値を求めてモニタ装置４
に出力する。また酸素の吹き込みを停止した時点で、Ｃ
Ｏガス分圧を求めて平衡到達炭素濃度を求め、溶鋼中の
炭素濃度との差を求めてその差が所定の範囲を超えた場
合、溶鋼温度を測定するようにモニタ装置４に出力す
る。モニタ装置４は、溶鋼中の炭素濃度及びＣｒの濃
度、Ｎｉの濃度並びに溶鋼温度を表示する一方、溶鋼温
度の測定を指示する表示を行う。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a block diagram showing a configuration of a refining control device for Cr-containing steel according to the present invention. From the process computer 1, the molten steel amount, composition, and temperature before the start of refining, and the set values of the amount of ferro-alloy, medium solvent, and ferro-alloy composition to be read are read, and the flow rate of the blown gas, the flow rate and the composition of the exhaust gas, and the vacuum degree Measuring devices 21 and
Take in from 2,23. The control device 3 uses these set values and measured values to determine the carbon concentration and the Cr concentration,
The monitoring device 4 obtains the estimated values of the concentration of i and the temperature of the molten steel.
Output to At the time when oxygen blowing is stopped, C
The O 2 gas partial pressure is determined to determine the equilibrium carbon concentration, and the difference from the carbon concentration in the molten steel is determined. The monitor device 4 displays the concentration of carbon and the concentration of Cr, the concentration of Ni, and the temperature of the molten steel in the molten steel, and displays a command to measure the temperature of the molten steel.
【００５３】図２は、本発明におけるＣｒ含有鋼の精錬
制御装置の計算手順を説明するフローチャートである。
プロセスコンピュータ１から本発明を実施するために必
要な設定値を読み込み（ステップ１）、測定装置２１、
２２、２３及び２４から測定値を取り込む（ステップ
２）。物質収支から溶鋼中の炭素濃度の推定値［％Ｃ］
n を求め（ステップ３）、吹き込みガス流量及び排出ガ
スの流量と組成の測定値より溶鋼中のＡｌ、Ｓｉ及びＭ
ｎの酸化量の推定値を求め（ステップ４）、次にＣｒ及
びＮｉの酸化量の推定値を求める（ステップ５）。溶鋼
中のＣｒ及びＮｉの濃度の推定値を求め（ステップ６、
７）、溶鋼温度を求める（ステップ８）。FIG. 2 is a flowchart illustrating the calculation procedure of the refining control device for Cr-containing steel according to the present invention.
A set value required to implement the present invention is read from the process computer 1 (step 1),
The measured values are taken from 22, 23 and 24 (step 2). Estimated carbon concentration in molten steel from material balance [% C]
n is determined (step 3), and the Al, Si and M in the molten steel are obtained from the measured values of the flow rate and composition of the blown gas and the exhaust gas.
An estimated value of the oxidation amount of n is obtained (step 4), and then an estimated value of the oxidation amount of Cr and Ni is obtained (step 5). Estimates of the concentrations of Cr and Ni in the molten steel are obtained (Step 6,
7) Find the molten steel temperature (step 8).
【００５４】そして、酸素の吹き込みを停止した時点で
あるか否か判断する（ステップ９）。停止した時点なら
ば、これらの推定値を用いて平衡到達炭素濃度［％Ｃ］
ｋを求める（ステップ１０）。溶鋼中の炭素濃度の推定
値と平衡到達炭素濃度との差が所定の範囲内にあるか否
か判定するために、その差の絶対値を求め、予め設定し
た許容値ΔＣ（％）より小さいか否か判定する（ステッ
プ１１）。ここで、許容値よりも大きかった場合、溶鋼
温度の測定を行う（ステップ１２）。そして、この測定
値を用いて溶鋼温度補正値を求め（ステップ１３）、こ
の補正値を用いて溶鋼温度の推定値を補正し、平衡到達
炭素濃度を求める（ステップ１４）。さらにこの平衡到
達炭素濃度を用いて溶鋼中炭素量補正値を求め（ステッ
プ１５）、精錬を停止する指示があるまで（ステップ１
６）上記の計算を繰り返す。Then, it is determined whether or not the time at which the blowing of oxygen is stopped is reached (step 9). If stopped, these estimated values are used to reach the equilibrium carbon concentration [% C].
k is obtained (step 10). In order to determine whether the difference between the estimated value of the carbon concentration in the molten steel and the carbon concentration attained by equilibrium is within a predetermined range, the absolute value of the difference is determined, and is smaller than a predetermined allowable value ΔC (%). It is determined whether or not (step 11). Here, if it is larger than the allowable value, the temperature of the molten steel is measured (step 12). Then, a molten steel temperature correction value is obtained by using the measured value (step 13), and the estimated value of the molten steel temperature is corrected by using the correction value to obtain an attained carbon concentration (step 14). Further, using this equilibrium reached carbon concentration, a correction value of the amount of carbon in the molten steel is obtained (step 15), and until an instruction to stop refining is given (step 1).
6) Repeat the above calculation.
【００５５】図３は溶鋼中の炭素濃度の実測値と平衡到
達炭素濃度との比較図である。この平衡到達炭素濃度は
溶鋼温度だけ測定値を用いて求めたものであり、採取サ
ンプルの溶鋼中の炭素濃度との関係を、横軸を採取サン
プルの溶鋼中の炭素濃度、縦軸を平衡到達炭素濃度とし
たグラフ上に黒点で示している。そこに採取サンプルの
溶鋼中の炭素濃度と平衡到達炭素濃度とが一致すること
を示す直線を引くことにより、ばらつきがσ＝０．００
２０％しかないことから、平衡到達炭素濃度は採取サン
プルの溶鋼中の炭素濃度分析値と一致していることがわ
かる。FIG. 3 is a comparison diagram of the measured carbon concentration in the molten steel and the carbon concentration attained by equilibrium. This equilibrium carbon concentration was determined using the measured value of the molten steel temperature only.The relationship between the carbon concentration in the molten steel of the sample and the carbon concentration in the molten steel of the sample was plotted on the horizontal axis, and the equilibrium was reached on the vertical axis. Black points are shown on the graph of the carbon concentration. By drawing a straight line indicating that the carbon concentration in the molten steel of the sampled sample and the carbon concentration attained by equilibrium match, the variation was σ = 0.00.
Since there is only 20%, it can be seen that the equilibrium carbon concentration is consistent with the carbon concentration analysis value in the molten steel of the collected sample.
【００５６】図４は、Ｃｒ含有鋼の精錬制御装置を用い
てＶＯＤプロセスにて精錬を行った結果を示すグラフで
ある。このときの実施条件を下記に示す。 精錬開始前の溶鋼の 溶鋼量 ７８９００ （ｋｇ） 溶鋼中の炭素濃度 ０．３５５ （％） 溶鋼中のＣｒの濃度 １６．２６ （％） 溶鋼中のＮｉの濃度 ０．０８ （％） 溶鋼温度 １５６０ （℃） 溶鋼温度が測定されて（２０）式が 演算されるまでの（２）式中のＫｃ ０ （ｋｇ） 溶鋼温度が測定されて（１９）式が 演算されるまでの（１７）式中のＫｔ ０ （℃） 溶鋼中の炭素濃度の推定値と平衡到達 炭素濃度との差の許容値ΔＣ ０．００５ （％） （５）式中のＰＭｎ ０．２４ （−） （１７）式中のＣｐ １８９ （ｋｃａｌ ／ｔｏｎ・ｋ） （１７）式中のＨL ２．６ （℃／ｍ ｉｎ） 単位時間Δｔ ０．００２７８（ｈｒ）FIG. 4 is a graph showing the results of refining in a VOD process using a refining control device for Cr-containing steel. The implementation conditions at this time are shown below. Amount of molten steel before refining 78900 (kg) Carbon concentration in molten steel 0.355 (%) Cr concentration in molten steel 16.26 (%) Ni concentration in molten steel 0.08 (%) Molten steel temperature 1560 (° C) Kc 0 (kg) in equation (2) from when the molten steel temperature is measured until equation (20) is calculated Equation (17) from when the molten steel temperature is measured and equation (19) is calculated Kt 0 (° C.) Estimated value of carbon concentration in molten steel and equilibrium reached Allowable value ΔC 0.005 (%) of difference between carbon concentration PMn 0.24 (−) in equation (5) (17) Cp 189 (kcal / ton · k) in equation (17) H L 2.6 in equation (° C./min) Unit time Δt 0.00278 (hr)
【００５７】（ａ）は本発明の方法によるものであり、
溶鋼中の炭素濃度，Ｃｒの濃度，Ｎｉの濃度及び溶鋼温
度の推定値の時間的推移と、酸素の吹き込みを停止した
時点で溶鋼中の炭素濃度の推定精度が良好であるか否か
判定した結果、悪かったので溶鋼温度を測定した時点と
を表示した。(A) is according to the method of the present invention,
The time course of the estimated values of carbon concentration, Cr concentration, Ni concentration and molten steel temperature in molten steel and whether or not the estimation accuracy of carbon concentration in molten steel was good at the time when oxygen injection was stopped was determined. Since the result was bad, the time when the molten steel temperature was measured is indicated.
【００５８】（ｂ）は従来の方法を再現したものであ
る。精錬開始前の溶鋼における諸条件を同じにするが、
溶鋼中のＣｒ濃度，Ｎｉの濃度及び溶鋼温度の推定値の
時間的推移を表示せず、かつ平衡到達炭素濃度の演算を
停止し、溶鋼中の炭素濃度の推定値の時間的推移のみ表
示した。(B) is a reproduction of the conventional method. The conditions in molten steel before refining start are the same,
The temporal changes of the estimated values of the Cr concentration, Ni concentration and the molten steel temperature in the molten steel are not displayed, and the calculation of the equilibrium reached carbon concentration is stopped, and only the temporal changes of the estimated values of the carbon concentration in the molten steel are displayed. .
【００５９】精度確認のために、本発明及び従来の方法
による精錬の実施中に溶鋼中の炭素濃度の推定値がいず
れも０．０２０％になった時点において、溶鋼を一部採
取して分析を行った。In order to confirm the accuracy, when the estimated value of the carbon concentration in the molten steel became 0.020% during the refining according to the present invention and the conventional method, a part of the molten steel was sampled and analyzed. Was done.
【００６０】本発明では表１より溶鋼中の炭素濃度及び
Ｃｒの濃度の推定値が実績値とほぼ一致していることが
わかる。In the present invention, it can be seen from Table 1 that the estimated values of the carbon concentration and the Cr concentration in the molten steel almost coincide with the actual values.
【表１】 [Table 1]
【００６１】ところが、従来の方法では表２より溶鋼中
の炭素濃度の実績値に対して推定値が著しく低いことか
ら過剰脱炭に至っていることがわかる。またＣｒの酸化
量が著しく増大していることが把握できる。However, in the conventional method, it can be seen from Table 2 that the estimated value is much lower than the actual value of the carbon concentration in the molten steel, resulting in excessive decarburization. Also, it can be understood that the oxidation amount of Cr has increased significantly.
【表２】 [Table 2]
【００６２】従って、本発明では従来方法よりも溶鋼中
の炭素濃度及びＣｒの濃度の推定精度が向上したことに
よって、過剰脱炭を防止することができ、Ｃｒの酸化損
失を抑制できることが確認できた。Therefore, in the present invention, it was confirmed that the accuracy of estimating the carbon concentration and the Cr concentration in the molten steel was improved as compared with the conventional method, so that excessive decarburization could be prevented and the oxidation loss of Cr could be suppressed. Was.
【００６３】[0063]
【発明の効果】第１発明に係る炭素濃度推定方法は、酸
素の吹き込みを開始した後、排出ガスの流量及び組成を
測定して物質収支より溶鋼中の炭素、Ｃｒ及びＮｉの濃
度を推定し、酸素の吹き込みを停止した後、推定した溶
鋼中のＣｒ、Ｎｉの濃度と溶鋼温度と減圧真空度を測定
して得るＣＯガス分圧を用いて平衡到達炭素濃度を求
め、この平衡到達炭素濃度と溶鋼中の炭素濃度の推定値
との差を求めることにより溶鋼中炭素濃度補正値が得ら
れることから、溶鋼中の炭素濃度を精度良く推定するこ
とが可能となる。The carbon concentration estimating method according to the first aspect of the present invention estimates the concentrations of carbon, Cr and Ni in the molten steel from the material balance by measuring the flow rate and composition of the exhaust gas after starting the blowing of oxygen. After stopping the injection of oxygen, the estimated concentration of Cr and Ni in the molten steel, and the CO gas partial pressure obtained by measuring the molten steel temperature and the degree of vacuum under reduced pressure are used to determine the equilibrium carbon concentration. By obtaining the difference between the estimated value of the carbon concentration in the molten steel and the estimated value of the carbon concentration in the molten steel, the carbon concentration in the molten steel can be accurately estimated.
【００６４】第２発明に係る炭素濃度推定方法は、酸素
の吹き込みを開始した後、熱収支より溶鋼温度を推定
し、酸素の吹き込みを停止した後で求めた平衡到達炭素
濃度と溶鋼中の炭素濃度との差が所定の範囲を超える値
であった場合、溶鋼温度を測定するだけで溶鋼中温度補
正値及び溶鋼中炭素量補正値が得られ、溶鋼中の炭素濃
度を補正することができるために、引き続き溶鋼中の炭
素濃度を精度良く推定することができる。In the carbon concentration estimating method according to the second invention, the temperature of the molten steel is estimated from the heat balance after the oxygen blowing is started, and the carbon concentration in the molten steel and the attained equilibrium concentration obtained after the oxygen blowing is stopped. When the difference from the concentration is a value exceeding a predetermined range, a molten steel temperature correction value and a molten steel carbon amount correction value can be obtained only by measuring the molten steel temperature, and the carbon concentration in the molten steel can be corrected. Therefore, the carbon concentration in the molten steel can be estimated with high accuracy.
【００６５】第３発明に係る炭素濃度推定方法は、酸素
の吹き込みを停止した後で求めた平衡到達炭素濃度と溶
鋼中の炭素濃度との差が所定の範囲内の値であった場
合、この溶鋼中の炭素濃度の推定精度が良好であると判
定できるため、引き続き溶鋼中の炭素濃度を精度良く推
定することができる。The carbon concentration estimating method according to the third invention is characterized in that the difference between the carbon concentration in the molten steel and the carbon concentration in the molten steel obtained after stopping the blowing of oxygen is within a predetermined range. Since it can be determined that the estimation accuracy of the carbon concentration in the molten steel is good, the carbon concentration in the molten steel can be continuously estimated with high accuracy.
【００６６】第４発明に係る精錬方法は、第２及び第３
発明でなし得る溶鋼中の炭素濃度の推定を元にして精錬
を行うために、従来必要とされてきた溶鋼のサンプリン
グ及び分析に伴う精錬時間の延長を解消できるうえに、
過剰脱炭を防止しＣｒの酸化損失を抑制することが可能
となる等、本発明は優れた効果を奏する。The refining method according to the fourth invention comprises the second and third refining methods.
In order to perform refining based on the estimation of the carbon concentration in molten steel that can be achieved by the invention, it is possible to eliminate the prolonged refining time accompanying the sampling and analysis of molten steel, which has been conventionally required,
The present invention has excellent effects such as preventing excessive decarburization and suppressing the oxidation loss of Cr.
【図１】本発明におけるＣｒ含有鋼の精錬制御装置のブ
ロック図である。FIG. 1 is a block diagram of a refining control device for Cr-containing steel according to the present invention.
【図２】本発明におけるＣｒ含有鋼の精錬制御装置の計
算手順を示すフローチャートである。FIG. 2 is a flowchart showing a calculation procedure of a refining control device for Cr-containing steel according to the present invention.
【図３】溶鋼中の炭素濃度の実測値と平衡到達炭素濃度
との比較図である。FIG. 3 is a graph comparing a measured value of carbon concentration in molten steel with an attained carbon concentration.
【図４】本発明の方法及び従来の方法によるＣｒ含有鋼
の精錬を行ったときの溶鋼成分の推移を示すグラフであ
る。FIG. 4 is a graph showing transition of molten steel components when refining Cr-containing steel by the method of the present invention and the conventional method.
１ プロセスコンピュータ ２１ 吹き込みガス測定装置 ２２ 排出ガス測定装置 ２３ 減圧真空度測定装置 ２４ 溶鋼温度測定装置 ３ 制御装置 ４ モニタ装置 DESCRIPTION OF SYMBOLS 1 Process computer 21 Blowing gas measuring device 22 Exhaust gas measuring device 23 Decompression vacuum degree measuring device 24 Molten steel temperature measuring device 3 Control device 4 Monitoring device
Claims (4)
て、酸素の吹き込みを開始した後、排出ガスの流量及び
組成を測定して物質収支より溶鋼中の炭素、Ｃｒ及びＮ
ｉの濃度を推定し、酸素の吹き込みを停止した後、推定
したＣｒ及びＮｉの濃度と、溶鋼温度と、減圧真空度か
ら求めたＣＯガス分圧とを用いて平衡到達炭素濃度を求
め、求めた平衡到達炭素濃度と推定した溶鋼中の炭素濃
度との差から溶鋼中炭素量補正値を求め、爾後、求めた
溶鋼中炭素量補正値を用いて溶鋼中の炭素濃度を推定す
ることを特徴とする炭素濃度推定方法。1. In refining a Cr-containing steel under reduced pressure, after oxygen blowing is started, the flow rate and composition of exhaust gas are measured, and carbon, Cr and N in molten steel are measured from a material balance.
After estimating the concentration of i and stopping the blowing of oxygen, the equilibrium carbon concentration was determined by using the estimated Cr and Ni concentrations, the molten steel temperature, and the CO gas partial pressure determined from the vacuum degree under reduced pressure. It is characterized in that a correction value of carbon content in molten steel is obtained from a difference between the reached carbon concentration in equilibrium and the estimated carbon concentration in molten steel, and then the carbon concentration in molten steel is estimated using the calculated correction value of carbon content in molten steel. Carbon concentration estimation method.
り溶鋼温度を推定し、酸素の吹き込みを停止した後、推
定した溶鋼温度を用いて平衡到達炭素濃度を求め、求め
た平衡到達炭素濃度と前記溶鋼中の炭素濃度との差が所
定の範囲外にある場合、溶鋼温度を測定し、測定した溶
鋼温度と推定した溶鋼温度との差から溶鋼温度補正値を
求め、求めた溶鋼温度補正値を用いて平衡到達炭素濃度
を算出し、算出した平衡到達炭素濃度と前記溶鋼中の炭
素濃度との差から溶鋼中炭素量補正値を求め、爾後、求
めた溶鋼温度補正値及び溶鋼中炭素量補正値を用いて溶
鋼温度及び溶鋼中の炭素濃度を推定することを特徴とす
る請求項１記載の炭素濃度推定方法。2. After the oxygen blowing is started, the temperature of the molten steel is estimated from the heat balance, the blowing of oxygen is stopped, and the carbon concentration attained equilibrium is determined using the estimated temperature of the molten steel. And the difference between the carbon concentration in the molten steel and the molten steel is outside a predetermined range, the molten steel temperature is measured, a molten steel temperature correction value is obtained from a difference between the measured molten steel temperature and the estimated molten steel temperature, and the obtained molten steel temperature correction is determined. The carbon concentration in the molten steel is calculated using the calculated carbon concentration in the molten steel, and the corrected carbon content in the molten steel is calculated from the difference between the calculated carbon concentration in the equilibrium and the carbon concentration in the molten steel. The method according to claim 1, wherein the temperature of the molten steel and the carbon concentration in the molten steel are estimated using the amount correction value.
中の炭素濃度との差が所定の範囲内にある場合、溶鋼中
の炭素濃度の推定が妥当であると判定し、引き続き溶鋼
温度及び溶鋼中の炭素濃度を推定することを特徴とする
請求項１乃至２記載の炭素濃度推定方法。3. When the difference between the obtained carbon concentration at equilibrium and the carbon concentration in the molten steel is within a predetermined range, it is determined that the estimation of the carbon concentration in the molten steel is appropriate, and the temperature and the temperature of the molten steel are continuously determined. 3. The carbon concentration estimating method according to claim 1, wherein the carbon concentration in the molten steel is estimated.
て、酸素の吹き込みを開始した後、排出ガスの流量及び
組成を測定して物質収支より溶鋼中の炭素濃度を推定
し、Ａｌ、Ｓｉ及びＭｎの酸化量の推定をして溶鋼中の
Ｃｒ及びＮｉの濃度を推定し、また熱収支から溶鋼温度
を推定し、酸素の吹き込みを停止した後、推定したＣ
ｒ、Ｎｉの濃度及び溶鋼温度と、測定した減圧真空度か
ら求めたＣＯガス分圧とを用いて平衡到達炭素濃度を求
め、求めた平衡到達炭素濃度と推定した前記溶鋼中の炭
素濃度との差を求めて得た値が所定の範囲内にある場
合、溶鋼中の炭素濃度の推定が妥当であると判定し、引
き続き推定した溶鋼温度及び溶鋼中の炭素濃度を元にし
て精錬を行い、前記平衡到達炭素濃度と前記溶鋼中の炭
素濃度との差が所定の範囲外にある場合、溶鋼温度を測
定し、測定した溶鋼温度と推定した溶鋼温度との差から
溶鋼温度補正値を求め、溶鋼温度補正値を用いて平衡到
達炭素濃度を算出し、算出した平衡到達炭素濃度と前記
溶鋼中の炭素濃度との差から溶鋼中炭素量補正値を求め
て、爾後、求めた溶鋼温度補正値及び溶鋼中炭素量補正
値を用いて推定した溶鋼温度及び溶鋼中の炭素濃度を元
にして精錬を行うことを特徴とする精錬方法。4. In refining of a Cr-containing steel under reduced pressure, after oxygen blowing is started, the flow rate and composition of the exhaust gas are measured to estimate the carbon concentration in the molten steel from the material balance, and Al, Si and Mn are obtained. The amount of oxidation of Cr was estimated by estimating the concentration of Cr and Ni in the molten steel, and the temperature of the molten steel was estimated from the heat balance.
r, the concentration of Ni and the temperature of the molten steel, and the equilibrium carbon concentration was determined using the CO gas partial pressure determined from the measured vacuum degree of vacuum, and the calculated equilibrium carbon concentration and the estimated carbon concentration in the molten steel were calculated. If the value obtained by obtaining the difference is within a predetermined range, it is determined that the estimation of the carbon concentration in the molten steel is appropriate, and then refined based on the estimated molten steel temperature and the carbon concentration in the molten steel, When the difference between the equilibrium reaching carbon concentration and the carbon concentration in the molten steel is outside a predetermined range, the molten steel temperature is measured, and a molten steel temperature correction value is obtained from a difference between the measured molten steel temperature and the estimated molten steel temperature, Using the molten steel temperature correction value to calculate the equilibrium carbon concentration, obtaining the carbon content correction value in the molten steel from the difference between the calculated equilibrium carbon concentration and the carbon concentration in the molten steel, and thereafter, the obtained molten steel temperature correction value And estimated using carbon steel correction value in molten steel Refining method characterized by performing refining based on the concentration of carbon in the steel temperature, and the molten steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15313298A JPH11350018A (en) | 1998-06-02 | 1998-06-02 | Method for estimating carbon concentration and refining method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15313298A JPH11350018A (en) | 1998-06-02 | 1998-06-02 | Method for estimating carbon concentration and refining method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11350018A true JPH11350018A (en) | 1999-12-21 |
Family
ID=15555702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15313298A Pending JPH11350018A (en) | 1998-06-02 | 1998-06-02 | Method for estimating carbon concentration and refining method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11350018A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003004707A1 (en) * | 2001-07-02 | 2003-01-16 | Nippon Steel Corporation | Method for decarbonization refining of chromium-containing molten steel |
| JP2019073799A (en) * | 2017-10-16 | 2019-05-16 | Ｊｆｅスチール株式会社 | Molten metal temperature correction device, molten metal temperature correction method, and production method of molten metal |
| CN111047202A (en) * | 2019-12-13 | 2020-04-21 | 首钢集团有限公司 | Method for correcting carbon content of molten iron |
-
1998
- 1998-06-02 JP JP15313298A patent/JPH11350018A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003004707A1 (en) * | 2001-07-02 | 2003-01-16 | Nippon Steel Corporation | Method for decarbonization refining of chromium-containing molten steel |
| US6830606B2 (en) | 2001-07-02 | 2004-12-14 | Nippon Steel Corporation | Method for decarbonization refining of chromium-containing molten steel |
| JP2010133030A (en) * | 2001-07-02 | 2010-06-17 | Nippon Steel Corp | Method for decarbonization refining of chromium-containing molten steel under reduced pressure |
| JP2019073799A (en) * | 2017-10-16 | 2019-05-16 | Ｊｆｅスチール株式会社 | Molten metal temperature correction device, molten metal temperature correction method, and production method of molten metal |
| CN111047202A (en) * | 2019-12-13 | 2020-04-21 | 首钢集团有限公司 | Method for correcting carbon content of molten iron |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101362712B1 (en) | Control of the converter process by means of exhaust gas signals | |
| JP2017008349A (en) | Device for and method of estimating molten metal condition | |
| JP5225308B2 (en) | Vacuum decarburization refining method for chromium-containing molten steel | |
| JP3287204B2 (en) | End point carbon concentration control method and carbon concentration control device in RH vacuum degasser | |
| JPH11350018A (en) | Method for estimating carbon concentration and refining method | |
| JP6825711B2 (en) | Molten component estimation device, molten metal component estimation method, and molten metal manufacturing method | |
| JP4353054B2 (en) | Method for decarburizing molten steel in RH vacuum degassing equipment | |
| JP6822148B2 (en) | Dehydrogenation refining method for molten steel | |
| JP5760982B2 (en) | Method for refining molten steel | |
| JP3126374B2 (en) | Vacuum decarburization control method for molten steel | |
| JPH06256832A (en) | Blowing method of converter | |
| KR101570582B1 (en) | Vacuum Oxygen decarburization apparatus of chromium comprising melting steel and vacuum oxygen decarburization method using the apparatus | |
| KR20000045516A (en) | Method and device for predicting concentration of carbon in molten metal in electric furnace work | |
| WO2023218914A1 (en) | Control device for vacuum degassing equipment, control method for vacuum degassing equipment, operation method, and manufacturing method for molten steel | |
| JP2005206877A (en) | Method for estimating carbon concentration at blowing time in converter | |
| JPH0125369B2 (en) | ||
| JP2000345227A (en) | Method for refining molten raw stainless steel | |
| JP3827852B2 (en) | Denitrification method for chromium-containing molten steel | |
| JPS5928515A (en) | Method and apparatus for refining steel | |
| JPS6225728B2 (en) | ||
| JPH0543931A (en) | Method for decarbonizing molten stainless steel | |
| JPS6246605B2 (en) | ||
| CN117310086A (en) | Method for correcting carbon potential by using three-gas analyzer | |
| JPS59185720A (en) | Decarburization refining method of molten steel under reduced pressure | |
| JPS6246606B2 (en) |