JP2004211120A - Method for producing high cleanliness steel - Google Patents
Method for producing high cleanliness steel Download PDFInfo
- Publication number
- JP2004211120A JP2004211120A JP2002379232A JP2002379232A JP2004211120A JP 2004211120 A JP2004211120 A JP 2004211120A JP 2002379232 A JP2002379232 A JP 2002379232A JP 2002379232 A JP2002379232 A JP 2002379232A JP 2004211120 A JP2004211120 A JP 2004211120A
- Authority
- JP
- Japan
- Prior art keywords
- ppm
- steel
- molten steel
- removal
- vacuum degassing
- 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
Images
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
【０００１】
【発明の属する技術分野】
本発明は、高清浄鋼の溶製方法に関し、特に高純度鋼や珪素鋼、その他の冷延鋼板に要求される高純度レベルまで、窒素（Ｎ）、硫黄（Ｓ）およびリン（Ｐ）等の不純物元素の有利な低減を図ろうとするものである。
【０００２】
【従来の技術】
近年、鋼の高純度化に対する要求がますます高まり、それに伴って、より低Ｎ、低Ｓ、低Ｐの溶鋼が求められている。
こうした要請に応えられる従来技術としては、真空脱ガス装置の浸漬管耐火物の外周を水素または水素と不活性ガスを主成分とするガスでシールすることによって、空気中の窒素の吸収を防止すると共に、該耐火物を介して水素を積極的に溶鋼中に混入させて脱炭を促進することにより、極低Ｃ、極低Ｎ鋼を溶製する方法（特許文献１）が知られている。
【０００３】
また、真空脱ガス槽と組み合わせた取鍋内の溶鋼を減圧精錬する際、未脱酸溶鋼への不活性ガスと脱硫剤の吹き込みを特定条件下で行うことによって、極低Ｃ、低Ｎ、極低Ｓ鋼を製造する方法（特許文献２）が提案されている。
さらに、鋼中炭素〔Ｃ〕に由来するＣＯガス気泡によって脱Ｎ反応を促進させ、真空脱ガス処理で極低Ｎ鋼を製造する方法（特許文献３）が提案されている。
【０００４】
【特許文献１】特開平6-306444号公報
【特許文献２】特開平3−281721号公報
【特許文献３】特開平7−166230号公報
【０００５】
【発明が解決しようとする課題】
極低Ｎ鋼の溶製技術としては、従来、転炉や電気炉等の一次精錬炉から取鍋へ出鋼する際、溶鋼中酸素を未脱酸として吸窒を防止し、RH真空脱ガス装置等の２次精錬装置で真空脱窒を行う方法が一般的であった。
しかしながら、高純度鋼においては、極低Ｎだけでなく極低Ｓも併せて達成する必要がある。ここに、脱Ｓ反応は、次式
〔Ｓ〕＋（CaO）→（CaS）＋〔Ｏ〕
のようにして生起するため、この反応を促進させるためには、溶鋼脱酸を行って鋼中酸素ポテンシャルを低下させると共に、塩基度の高いスラグを用いる必要がある。
【０００６】
このため、低Ｎ化を優先して溶鋼を未脱酸とすると、脱Ｓは進まない。未脱酸溶鋼に、脱Ｓ用のフラックスインジェクションを行っても、鋼中Ｓ量はせいぜい〔Ｓ〕：20〜30 ppm程度までしか低減できず、本発明で目標とする〔Ｓ〕≦９ ppmを達成することは不可能である。
〔Ｓ〕≦９ ppmの溶鋼を得るには、脱Ｓを優先して、一次精錬炉から出鋼した溶鋼をAl等の脱酸剤を用いて溶鋼の酸素ポテンシャルを下げると同時に、高塩基度スラグとした後、ＬＦ（レードルファーネス）等の取鍋精錬炉において脱Ｓ用のフラックスインジェクションを行うことにより、脱Ｓ化を図る必要がある。
【０００７】
また、脱Ｐ反応は、次式
２〔Ｐ〕＋５（FeＯ）＝（P２O５)＋５〔Fe〕
の酸化反応で起こるため、一次精錬炉で脱炭を行い、その時にスラグ中FeＯを高めて脱Ｐを促進させる方法が一般的に採用されている。
しかしながら、〔Ｐ〕≦45 ppmの極低リン鋼の溶製となると、転炉流出スラグからの復Ｐにも注意を払う必要がある。また、上掲式の反応からも判るように、脱Ｐ反応は酸化反応であるのに対し、脱Ｓ反応は還元反応であり、両者は相反するものである。
【０００８】
上述した知見から、極低Ｎ、極低Ｓ、極低Ｐ鋼を溶製するには、以下の考え方で行うのがよいと考えられる。
すなわち、まず、転炉や電気炉等の一次精錬炉で、脱Ｃ、脱Ｐを行ったのち、ＬＦやフラックスインジェクションで脱Ｓ処理を行い、ついでＲＨ真空脱ガス装置で脱Ｎ処理を行うことである。なお、ＬＦやフラックスインジェクションおよびＲＨ真空脱ガス装置の代わりにＶＯＤ等を用いることも有効と考えられるが、ＶＯＤでは取鍋耐火物コストが高くなるので、炭素鋼の製造には適していないと考えられる。
また、溶銑を一次精錬炉に装入する前に、溶銑予備処理を行って溶銑中のＰ，Ｓを極力下げておくことは有効である。
【０００９】
そこで、発明者らは、転炉、ＬＦ（あるいはフラックスインジェクション）およびRH真空脱ガス装置を種々に組み合わせて、表１に示す製造プロセスで鋼を溶製し、その際の各種不純物元素の到達低減レベルについて調査した。
得られた結果を表１に併記する。
【００１０】
【表１】
同表に示したとおり、いずれの製造プロセスにおいても、本発明の目標である〔Ｎ〕≦25 ppm、〔Ｓ〕≦９ ppm、〔Ｐ〕≦45 ppmを同時に達成することはできなかった。
【００１２】
そこで、次に、極低Ｎ化を目指して、真空下における平衡Ｎを計算した。
平衡Ｎは、「鉄冶金熱力学 P.133」（大谷ら）によれば、次式(1)
log〔％Ｎ〕＝−〔（188/Ｔ）＋1.246〕＋〔（logＰＮ２）／２〕 --- (1)
ここで、Ｔ：溶鋼温度（℃）
ＰＮ２：窒素分圧（atm ）
で表すことができ、ＰＮ２がそれぞれ0.5 torr、1.0 torrの時、〔％Ｎ〕はそれぞれ12 ppm、16 ppmとなる。
従って、14 ppm程度がＲＨ真空脱ガス処理で到達可能なＮレベルである。
【００１３】
上掲した表１中、製造プロセスａでは、RH後に〔Ｎ〕を20 ppm以下まで低減できたとしても、大気中でのＬＦ処理中に吸Ｎが起こり、結局、〔Ｎ〕は45 ppm
程度となってしまう。
また、製造プロセスｂでも、ＬＦにて脱Ｓ処理を行うと吸Ｎが起こるが、RH後では30〜40 ppmまで低減することができる。
さらに、ＬＦを省略する製造プロセスｃでは、〔Ｎ〕は20 ppm以下に低減できるものの、脱Ｓができないため〔Ｓ〕≦９ ppmを達成することはできない。
【００１４】
【課題を解決するための手段】
本発明は、上記の問題を有利に解決するもので、溶鋼中のＮ，ＳおよびＰ量がそれぞれ、〔Ｎ〕≦25 ppm、〔Ｓ〕≦９ ppm、〔Ｐ〕≦45 ppmを満足する高清浄鋼の有利な溶製方法を提案することを目的とする。
【００１５】
すなわち、本発明は、予備処理済みの溶銑を、転炉または電気炉等の一次精錬炉にて脱Ｃ、脱Ｐした未脱酸溶鋼を、出鋼後、除滓し、取鍋精錬に先立って加炭した後、脱Ｓ用フラックスインジェクションを行い、ついでAl脱酸後、ＲＨ真空脱ガス槽に移送し、送酸することによってAl昇熱を図り、このAl昇熱により脱炭量が0.05〜0.20mass％の脱Ｃを行うと共に、この脱Ｃ反応に伴う脱Ｎを利用することにより、溶鋼中のＮ，ＳおよびＰ量をそれぞれ、〔Ｎ〕≦25 ppm、〔Ｓ〕≦９ ppm、〔Ｐ〕≦45 ppmに低減することを特徴とする高清浄鋼の溶製方法である。
【００１６】
また、本発明では、ＲＨ真空脱ガス槽におけるAl昇熱時に生成するAl２O３に対して、CaＯ含有フラックスを添加することが有利である。
【００１７】
【発明の実施の形態】
以下、本発明の解明経緯について説明する。
さて、本発明では、前記の課題を達成するために、ＬＦにおける脱Ｓ処理とＲＨ真空脱ガス処理の組み合わせにより、復Ｐを防止しつつ脱Ｓと脱Ｎを如何に効果的に行うかについて調査を行った。
前掲特開平7−166230号公報には、鋼中炭素〔Ｃ〕に由来するＣＯガス気泡によって脱Ｎ反応を促進させる方法が開示されている。しかしながら、転炉では脱Ｐのために〔Ｃ〕を0.02mass％程度まで吹き下げる必要があるため、その後にＲＨ真空脱ガス処理を行っても〔Ｎ〕を25 ppm以下まで低減することはできない。
【００１８】
そこで、発明者らは、脱Ｎを促進するために、ＲＨスタート時における〔Ｃ〕を高くし、この状態でＲＨ真空槽内に送酸して脱炭を行った場合の脱Ｎ挙動について調査した。
得られた結果を表２に示す。
【００１９】
【表２】
同表に示したとおり、ＲＨにてΔＣ：0.10mass％程度の脱Ｃを行うことによって、ΔＮ：20ppm 程度の脱Ｎ効果が得られることが判明した。
【００２１】
しかしがら、加炭材は〔Ｓ〕を含んでいるため、ＲＨにて加炭すると〔Ｓ〕の値が上がってしまい、今度は〔Ｓ〕≦９ ppmを達成することができない。
また〔Ｓ〕≦９ ppmを達成するには、ＬＦ等の処理を行う必要があるが、RH送酸脱炭は酸化反応であるため、表１中、製造プロセスbで示したとおり、一旦下がった〔Ｓ〕がＲＨにて復Ｓしてしまう。
【００２２】
しかしながら、脱Ｎを考えると、製造プロセスaは吸Ｎが生じて脱Ｎができないため、製造プロセスbをベースにして、さらに調査を行った。
その結果、ＬＦにて脱Ｓ処理を行う前に加炭することにより、ＬＦにて加炭材からのＳ分も脱Ｓ処理できることが判った。また、ＬＦでの処理は還元反応であるため、一次精錬炉にてＴ.Feと反応したスラグ中のＰ２Ｏ５が残っていると溶鋼中に復Ｐするが、この点については、ＬＦ処理に先立ってスラグを除去することにより、解決することができる。
【００２３】
ところで、ＬＦにおいて脱Ｓを行う場合、Al等の脱酸剤を添加する。ＬＦの後にRHを用いた場合、鋼中Alは送酸によりAl２Ｏ３になるが、その際発熱反応を起こし、溶鋼の温度上昇に寄与する。
【００２４】
発明者らは、上記したＲＨでのAl昇熱による脱Ｃ処理における脱Ｎ挙動について調査したところ、表３に示すように、Al昇熱による脱Ｃ中に脱Ｎも併せて起きていることの知見を得た。
すなわち、Alを添加した上で送酸するとAl昇熱により溶鋼温度が上昇し、この際脱Ｃが進行するが、この脱Ｃ反応は吸熱反応なので、それに伴う温度低下によって脱Ｎが同時に進行することが究明されたのである。
【００２５】
【表３】
【実施例】
図１に、本発明に従う好適溶製プロセスを示す。
予備処理済みの溶銑を、転炉に装入し、転炉で脱Ｃ、脱Ｐを行ったのち、未脱酸状態で出鋼して吸Ｎを防止する。ついで、スラグを除去したのち、CaＯ含有フラックスの添加、加炭およびAl脱酸をＬＦ処理開始前に行う。ついで、ＬＦでフラックスインジェクションによる脱Ｓ処理後、送酸機能を有するRH真空脱ガス装置において、溶鋼に対して送酸し、Al昇熱による脱Ｃを行うと同時に、脱Ｎも併せて行う。
上記の製造プロセスによって溶製した溶鋼の成分組成の変化挙動について調べた結果を表４に示す。
【００２７】
【表４】
同表に示したとおり、本発明に従って溶製することにより、〔Ｎ〕≦25 ppm、〔Ｓ〕≦９ ppm、〔Ｐ〕≦45 ppmの高清浄鋼が得られることが判る。
また、RHにて生成するAl２Ｏ３とバランスするようにCaO 含有フラックスを添加した場合、溶鋼の清浄度がさらに向上することも確認された。
【００２９】
【発明の効果】
かくして、本発明によれば、〔Ｎ〕≦25 ppm、〔Ｓ〕≦９ ppm、〔Ｐ〕≦45 ppmを満足する極低Ｎ、極低Ｓ、極低Ｐの高清浄鋼を安定して得ることができる。
【図面の簡単な説明】
【図１】本発明に従う好適製造プロセスを示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for smelting high-purity steel, particularly to nitrogen (N), sulfur (S), phosphorus (P), etc., up to the high purity level required for high-purity steel, silicon steel, and other cold-rolled steel sheets. It is intended to achieve an advantageous reduction of impurity elements.
[0002]
[Prior art]
In recent years, there has been an increasing demand for higher purity steel, and accordingly, a lower N, lower S, lower P molten steel has been demanded.
As a conventional technology that meets such demands, absorption of nitrogen in the air is prevented by sealing the outer periphery of the refractory of a dip tube of a vacuum degassing device with hydrogen or a gas containing hydrogen and an inert gas as main components. In addition, a method is known in which hydrogen is actively mixed into molten steel through the refractory to promote decarburization, thereby producing extremely low C and extremely low N steel (Patent Document 1). .
[0003]
In addition, when the molten steel in the ladle combined with the vacuum degassing tank is subjected to vacuum refining, the inert gas and the desulfurizing agent are blown into the undeoxidized molten steel under specific conditions, so that extremely low C, low N, A method of manufacturing extremely low S steel (Patent Document 2) has been proposed.
Furthermore, a method has been proposed in which a degassing reaction is promoted by CO gas bubbles derived from carbon [C] in steel, and a very low N steel is produced by vacuum degassing (Patent Document 3).
[0004]
[Patent Document 1] JP-A-6-306444 [Patent Document 2] JP-A-3-281721 [Patent Document 3] JP-A-7-166230
[Problems to be solved by the invention]
Conventionally, the smelting technology of ultra-low N steel is as follows: When tapping steel from a primary smelting furnace such as a converter or electric furnace to a ladle, oxygen in the molten steel is not deoxidized to prevent nitrogen absorption and RH vacuum degassing. A method of performing vacuum denitrification with a secondary refining device such as a device has been common.
However, in high-purity steel, it is necessary to achieve not only extremely low N but also extremely low S. Here, the de-S reaction is represented by the following formula [S] + (CaO) → (CaS) + [O]
In order to promote this reaction, it is necessary to deoxidize molten steel to lower the oxygen potential in steel and use slag with a high basicity.
[0006]
For this reason, if the molten steel is not deoxidized by giving priority to the reduction of N, the removal of S does not proceed. Even if flux injection for S removal is performed on the undeoxidized molten steel, the S content in the steel can be reduced to at most only [S]: about 20 to 30 ppm, and the target [S] ≦ 9 ppm in the present invention. It is impossible to achieve.
[S] In order to obtain molten steel of ≤ 9 ppm, giving priority to the removal of S, the oxygen potential of the molten steel lowered from the molten steel discharged from the primary refining furnace using a deoxidizing agent such as Al, After the slag is formed, it is necessary to remove S by performing a flux injection for removing S in a ladle refining furnace such as LF (ladle furnace).
[0007]
The de-P reaction is performed by the following formula: 2 [P] +5 (FeO) = (P 2 O 5 ) +5 [Fe]
Therefore, a method is generally employed in which decarburization is performed in a primary smelting furnace and FeO in the slag is increased at that time to promote P removal.
However, when it comes to the production of extremely low phosphorus steel with [P] ≦ 45 ppm, it is necessary to pay attention to returning P from the slag flowing out of the converter. Further, as can be seen from the above-mentioned reactions, the de-P reaction is an oxidation reaction, while the de-S reaction is a reduction reaction, and both are contradictory.
[0008]
From the above-mentioned knowledge, it is considered that it is better to melt the ultra-low N, ultra-low S and ultra-low P steel in the following manner.
That is, first, after removing C and removing P in a primary refining furnace such as a converter or an electric furnace, removing S is performed by LF or flux injection, and then removing N is performed by an RH vacuum degassing device. It is. Although it is considered effective to use VOD instead of LF, flux injection and RH vacuum degassing equipment, VOD increases the cost of ladle refractories and is not suitable for the production of carbon steel. Can be
Before charging the hot metal into the primary smelting furnace, it is effective to perform hot metal pretreatment to reduce P and S in the hot metal as much as possible.
[0009]
Therefore, the inventors combined various types of converters, LF (or flux injection) and RH vacuum degassing devices, melted steel in the manufacturing process shown in Table 1, and reduced the arrival of various impurity elements at that time. The level was investigated.
The results obtained are also shown in Table 1.
[0010]
[Table 1]
As shown in the table, none of the manufacturing processes could simultaneously achieve the targets of the present invention [N] ≦ 25 ppm, [S] ≦ 9 ppm, and [P] ≦ 45 ppm.
[0012]
Then, next, the equilibrium N under vacuum was calculated aiming at extremely low N.
The equilibrium N can be calculated from the following equation (1) according to “Iron Metallurgy Thermodynamics P.133” (Otani et al.).
log [% N] =-[(188 / T) +1.246] + [(logP N2 ) / 2] --- (1)
Here, T: molten steel temperature (° C.)
P N2 : Nitrogen partial pressure (atm)
Can be represented by, when P N2 is 0.5 torr, respectively, of 1.0 torr, the [% N], respectively 12 ppm is, 16 ppm.
Therefore, about 14 ppm is the N level that can be reached by the RH vacuum degassing process.
[0013]
In Table 1 above, in the manufacturing process a, even if [N] could be reduced to 20 ppm or less after RH, N absorption occurred during LF treatment in the atmosphere, and eventually [N] was 45 ppm.
It will be about.
Also, in the manufacturing process b, the N absorption occurs when the S removal treatment is performed by LF, but can be reduced to 30 to 40 ppm after RH.
Further, in the manufacturing process c in which LF is omitted, [N] can be reduced to 20 ppm or less, but [S] ≦ 9 ppm cannot be achieved because desulfurization cannot be performed.
[0014]
[Means for Solving the Problems]
The present invention advantageously solves the above problem, and the amounts of N, S and P in molten steel satisfy [N] ≦ 25 ppm, [S] ≦ 9 ppm, and [P] ≦ 45 ppm, respectively. An object of the present invention is to propose an advantageous smelting method for high-purity steel.
[0015]
That is, in the present invention, the untreated deoxidized molten steel obtained by de-C / P removal of the pre-processed molten iron in a primary refining furnace such as a converter or an electric furnace, after tapping, removing slag and prior to ladle refining. After decarburizing, flux injection for de-S was carried out, then Al deoxidation was carried out, and then transferred to an RH vacuum degassing tank, and the acid was fed to raise the heat of Al. By performing the decarbonization of about 0.20 mass% and utilizing the decarbonization accompanying the decarbonization reaction, the amounts of N, S and P in the molten steel can be reduced to [N] ≦ 25 ppm and [S] ≦ 9 ppm, respectively. , [P] ≦ 45 ppm.
[0016]
In the present invention, it is advantageous to add a CaO-containing flux to Al 2 O 3 generated when Al is heated in the RH vacuum degassing tank.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the details of the invention will be described.
By the way, in the present invention, in order to achieve the above-mentioned subject, by combining the de-S treatment in the LF and the RH vacuum de-gas treatment, how to effectively perform the de-S and de-N while preventing recovery P A survey was conducted.
The above-mentioned Japanese Patent Application Laid-Open No. Hei 7-166230 discloses a method of accelerating the N removal reaction by using CO gas bubbles derived from carbon [C] in steel. However, in the converter, since [C] needs to be blown down to about 0.02 mass% for degassing, [N] cannot be reduced to 25 ppm or less even if RH vacuum degassing is performed thereafter. .
[0018]
Therefore, the present inventors increased [C] at the time of RH start in order to promote denitrification, and investigated denitrification behavior when acid was sent into the RH vacuum tank and decarburization was performed in this state. did.
Table 2 shows the obtained results.
[0019]
[Table 2]
As shown in the table, it has been found that by performing the decarburization of about 0.10 mass% at RH, a de-N effect of about 20 ppm can be obtained.
[0021]
However, since the carburized material contains [S], the value of [S] increases when carburized by RH, and it is not possible to achieve [S] ≦ 9 ppm this time.
In order to achieve [S] ≦ 9 ppm, it is necessary to perform a treatment such as LF. However, since RH acid decarburization is an oxidation reaction, as shown in the manufacturing process b in Table 1, the RH is once lowered. [S] is restored at RH.
[0022]
However, considering the removal of N, the production process a cannot absorb and remove N, so that further investigation was conducted based on the production process b.
As a result, it was found that by performing carburization before performing the de-S treatment in the LF, the S component from the carburized material could also be de-S treated in the LF. Further, since the treatment with LF is a reduction reaction, if P 2 O 5 in the slag reacted with T.Fe remains in the primary refining furnace, the slag returns to the molten steel, but in this regard, LF This can be solved by removing the slag prior to treatment.
[0023]
By the way, when performing S removal in LF, a deoxidizing agent such as Al is added. When RH is used after LF, Al in the steel is converted to Al 2 O 3 by acid supply, but at that time, an exothermic reaction occurs, which contributes to an increase in the temperature of the molten steel.
[0024]
The inventors investigated the denitrification behavior in the decarburization treatment by the above-described heating of Al at RH, and as shown in Table 3, it was found that denitration also occurred during the deheating of C by the heating of Al. Was obtained.
That is, when acid is fed after adding Al, the temperature of the molten steel rises due to the increase in heat of Al, and at this time, de-C proceeds. However, since this de-C reaction is an endothermic reaction, de-N is simultaneously advanced due to the accompanying temperature drop. It was determined.
[0025]
[Table 3]
【Example】
FIG. 1 shows a preferred smelting process according to the present invention.
The pretreated hot metal is charged into a converter, subjected to de-C and de-P in the converter, and then steel-extruded in a non-deoxidized state to prevent N absorption. Then, after removing the slag, addition of a CaO-containing flux, carburization and Al deoxidation are performed before the start of the LF treatment. Then, after the LF is subjected to flux removal by the flux injection, in a RH vacuum degassing apparatus having an acid sending function, the molten steel is sent to the steel, and the C is removed by raising the heat of Al, and the N is also removed at the same time.
Table 4 shows the results obtained by examining the change behavior of the component composition of the molten steel produced by the above production process.
[0027]
[Table 4]
As shown in the table, it can be seen that by melting according to the present invention, highly clean steels with [N] ≦ 25 ppm, [S] ≦ 9 ppm, and [P] ≦ 45 ppm can be obtained.
It was also confirmed that when a CaO-containing flux was added so as to balance with Al 2 O 3 generated by RH, the cleanliness of the molten steel was further improved.
[0029]
【The invention's effect】
Thus, according to the present invention, ultra-low N, ultra-low S and ultra-low P high clean steel satisfying [N] ≦ 25 ppm, [S] ≦ 9 ppm, and [P] ≦ 45 ppm can be stably obtained. Obtainable.
[Brief description of the drawings]
FIG. 1 illustrates a preferred manufacturing process according to the present invention.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002379232A JP3922181B2 (en) | 2002-12-27 | 2002-12-27 | Melting method of high clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002379232A JP3922181B2 (en) | 2002-12-27 | 2002-12-27 | Melting method of high clean steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004211120A true JP2004211120A (en) | 2004-07-29 |
| JP3922181B2 JP3922181B2 (en) | 2007-05-30 |
Family
ID=32815790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002379232A Expired - Fee Related JP3922181B2 (en) | 2002-12-27 | 2002-12-27 | Melting method of high clean steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3922181B2 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ297122B6 (en) * | 2005-07-26 | 2006-09-13 | TRINECKÉ ZELEZÁRNY, a. s. | Process for producing extremely pure steels |
| CN103215410A (en) * | 2013-04-18 | 2013-07-24 | 首钢总公司 | Method for improving cleanness of Nb-Ti containing steel |
| KR101424641B1 (en) | 2013-04-03 | 2014-08-01 | 주식회사 포스코 | Method for manufacturing cast metal pin iron |
| JP2015030868A (en) * | 2013-08-01 | 2015-02-16 | Ｊｆｅスチール株式会社 | Method for refining extra-low nitrogen pure iron |
| CN104946854A (en) * | 2015-06-04 | 2015-09-30 | 什邡市三裕锻件有限公司 | Steel smelting method |
| JP2016204693A (en) * | 2015-04-20 | 2016-12-08 | 新日鐵住金株式会社 | Production method of high cleanliness steel |
| CN111440981A (en) * | 2018-01-31 | 2020-07-24 | 日照钢铁控股集团有限公司 | Low-carbon silicon-aluminum-control killed clean steel process |
| WO2022249798A1 (en) | 2021-05-26 | 2022-12-01 | Ｊｆｅスチール株式会社 | Method for refining molten iron |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102978332A (en) * | 2012-12-26 | 2013-03-20 | 首钢总公司 | Smelting method of 9Ni steel |
| CN111299533A (en) * | 2020-04-03 | 2020-06-19 | 武汉钢铁有限公司 | Method for improving castability of ultra-low carbon steel produced by billet continuous casting machine |
-
2002
- 2002-12-27 JP JP2002379232A patent/JP3922181B2/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ297122B6 (en) * | 2005-07-26 | 2006-09-13 | TRINECKÉ ZELEZÁRNY, a. s. | Process for producing extremely pure steels |
| KR101424641B1 (en) | 2013-04-03 | 2014-08-01 | 주식회사 포스코 | Method for manufacturing cast metal pin iron |
| CN103215410A (en) * | 2013-04-18 | 2013-07-24 | 首钢总公司 | Method for improving cleanness of Nb-Ti containing steel |
| JP2015030868A (en) * | 2013-08-01 | 2015-02-16 | Ｊｆｅスチール株式会社 | Method for refining extra-low nitrogen pure iron |
| JP2016204693A (en) * | 2015-04-20 | 2016-12-08 | 新日鐵住金株式会社 | Production method of high cleanliness steel |
| CN104946854A (en) * | 2015-06-04 | 2015-09-30 | 什邡市三裕锻件有限公司 | Steel smelting method |
| CN111440981A (en) * | 2018-01-31 | 2020-07-24 | 日照钢铁控股集团有限公司 | Low-carbon silicon-aluminum-control killed clean steel process |
| CN111440981B (en) * | 2018-01-31 | 2021-06-25 | 日照钢铁控股集团有限公司 | Low-carbon silicon-aluminum-control killed clean steel process |
| WO2022249798A1 (en) | 2021-05-26 | 2022-12-01 | Ｊｆｅスチール株式会社 | Method for refining molten iron |
| KR20230162108A (en) | 2021-05-26 | 2023-11-28 | 제이에프이 스틸 가부시키가이샤 | Method of refining molten iron |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3922181B2 (en) | 2007-05-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5092245B2 (en) | Denitrification method for molten steel | |
| JP5910579B2 (en) | Melting method of ultra-low nitrogen pure iron | |
| JP4742740B2 (en) | Method for melting low-sulfur steel | |
| JP5386825B2 (en) | Method for melting Mn-containing ultra-low carbon steel | |
| JP3922181B2 (en) | Melting method of high clean steel | |
| JP4079097B2 (en) | Melting method of high clean steel | |
| JP5614306B2 (en) | Method for melting manganese-containing low carbon steel | |
| JP2016188401A (en) | Method for melting high manganese steel | |
| JP3966156B2 (en) | Method for melting ultra-low phosphorus stainless steel | |
| KR102189097B1 (en) | Pre-treatment method of molten iron and manufacturing method of ultra-low-tough steel | |
| JP4765374B2 (en) | Desulfurization treatment method for chromium-containing hot metal | |
| JP5831194B2 (en) | Method for melting manganese-containing low carbon steel | |
| JP2002020816A (en) | Method for producing low nitrogen-containing chromium steel | |
| CN110621793A (en) | Smelting method of high manganese steel | |
| JP2008184648A (en) | Method for desiliconizing and dephosphorizing molten pig iron | |
| JPH09235611A (en) | Production of extra-low sulfur pure iron having high cleanliness | |
| JP4534734B2 (en) | Melting method of low carbon high manganese steel | |
| JP4667841B2 (en) | Method for melting chromium-containing steel | |
| JPH06228626A (en) | Method for reforming slag as pretreatment of desulfurization | |
| JP2004043954A (en) | Ladle refining method for molten steel | |
| JP7480751B2 (en) | METHOD FOR DENITRATION OF MOLTEN STEEL AND METHOD FOR PRODUCING STEEL | |
| JPH0959708A (en) | Method for efficently decarburization-blowing stainless steel | |
| JP3922189B2 (en) | Ladle refining method for molten steel | |
| EP2751299A2 (en) | Method of alloying various grades of steel with manganese oxides | |
| JP2011084782A (en) | Method for producing high chromium steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20051122 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20061017 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20061031 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20061228 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070130 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070212 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |