JPH11279624A - Refining method of high-nitrogen stainless steel - Google Patents
Refining method of high-nitrogen stainless steelInfo
- Publication number
- JPH11279624A JPH11279624A JP7972598A JP7972598A JPH11279624A JP H11279624 A JPH11279624 A JP H11279624A JP 7972598 A JP7972598 A JP 7972598A JP 7972598 A JP7972598 A JP 7972598A JP H11279624 A JPH11279624 A JP H11279624A
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen
- gas
- molten steel
- vacuum
- stainless steel
- 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
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、高窒素ステンレス
溶鋼の溶製方法に係わり、より詳しくは、溶鋼の減圧精
錬処理（例えば、ＶＯＤ法による）において、溶鋼の窒
素濃度を低下させることなく、脱酸するというステンレ
ス溶鋼の加窒及び脱酸を同時に行う技術である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of smelting high-nitrogen stainless steel, and more particularly, to a method of reducing the nitrogen concentration of molten steel in a vacuum refining process (for example, by a VOD method) without reducing the nitrogen concentration of the molten steel. This is a technique to simultaneously denitrate and denitrate stainless steel molten steel.
【０００２】[0002]
【従来の技術】近年、ステンレス鋼の分野においては、
耐食性や強度等の向上、あるいは高価なＮｉ源の低減の
目的で、鋼中に積極的に窒素を含有させた鋼種が開発さ
れている。ところで、ステンレス鋼を溶製する精錬段階
では、高価なＣｒの酸化損失を極力低減しつつ鋼中の炭
素濃度を低減すること、及び非金属介在物を形成する鋼
中の酸素濃度を低減することを目的として、減圧精錬を
行うのが一般的である。2. Description of the Related Art In recent years, in the field of stainless steel,
For the purpose of improving corrosion resistance and strength, or reducing expensive Ni sources, steel grades in which nitrogen is actively contained in steel have been developed. By the way, in the refining stage of smelting stainless steel, it is necessary to reduce the carbon concentration in steel while minimizing the oxidation loss of expensive Cr, and to reduce the oxygen concentration in steel that forms nonmetallic inclusions. In general, vacuum refining is performed for the purpose.
【０００３】この溶鋼中の酸素濃度に関しては、スラグ
の塩基度（ＣａＯ／ＳｉＯ2 ）を高くすると、スラグ−
メタル反応によるＳｉ−Ｏ平衡で決まる鋼中酸素濃度
が、真空下（３０〜１００ｔｏｒｒ）でのＣ−Ｏ反応で
決まる酸素濃度よりも低くなるので、溶鋼中の酸素濃度
をより低下させることができる。しかしながら、スラグ
の塩基度が高くなると、スラグの滓化が悪化するため
に、ＣａＦ2 あるいはＡｌ 2 Ｏ3 を添加しなければなら
ず、取鍋耐火物の溶損量が増大したり、スラグ中のＡｌ
2 Ｏ3 がＳｉで還元され、溶鋼中にＡｌ2 Ｏ3 介在物が
生成し、Ｓｉキルド鋼であるにもかかわらず、後工程の
連続鋳造時にＡｌ2 Ｏ3 介在物によるノズル詰まりや製
品の欠陥を多発させる。そのため、高塩基度スラグを形
成させるような脱酸処理は、難かしいものであった。[0003] Regarding the oxygen concentration in the molten steel, slag
Basicity (CaO / SiOTwo ), Slag-
Oxygen concentration in steel determined by Si-O equilibrium due to metal reaction
Is a C—O reaction under vacuum (30-100 torr)
The oxygen concentration in the molten steel is lower than the determined oxygen concentration.
Can be further reduced. However, slag
If the basicity of the slag becomes high,
And CaFTwo Or Al Two OThree Must be added
The erosion of the ladle refractory increases,
Two OThree Is reduced by Si, and AlTwo OThree Inclusions
Despite being a Si-killed steel,
Al during continuous castingTwo OThree Nozzle clogged or produced by inclusions
Frequent product defects. Therefore, high basicity slag is formed.
The deoxidizing treatment to be performed is difficult.
【０００４】ところで、減圧精錬法でも、特にＶＯＤ法
は、ステンレス鋼の脱炭及び脱窒に関しては優れたもの
である。従って、それを前述したような高窒素ステンレ
ス鋼の溶製に採用すると、窒素濃度が低下し過ぎてしま
い、脱酸処理後に、窒素含有合金を添加して加窒を実施
する必要があった。そのため、全体の精錬時間が延長し
てしまうという問題がある。また、この窒素濃度の低下
を抑えるには、図３に示すＶＯＤ真空装置１内の真空度
を下げ、窒素分圧を高くすることが考えられるが、真空
度を低下するとＣＯ分圧も上昇するので、Ｆｅ−Ｓｉ合
金の添加後に期待するＣＯ反応による脱酸反応が停滞
し、ＶＯＤ処理後の溶鋼中の酸素濃度が増加してしまう
という問題もあった。つまり、酸素濃度の低い高窒素ス
テンレス鋼を安定して溶製する適切な方法が存在しない
のが現状である。[0004] Among the vacuum refining methods, the VOD method is particularly excellent in decarburizing and denitrifying stainless steel. Therefore, if it is used for melting high-nitrogen stainless steel as described above, the nitrogen concentration will be too low, and after the deoxidizing treatment, it is necessary to add a nitrogen-containing alloy to perform nitriding. Therefore, there is a problem that the entire refining time is extended. In order to suppress the decrease in the nitrogen concentration, it is conceivable to decrease the degree of vacuum in the VOD vacuum apparatus 1 shown in FIG. 3 and increase the partial pressure of nitrogen. However, when the degree of vacuum is reduced, the partial pressure of CO also increases. Therefore, there is also a problem that the deoxidation reaction due to the CO reaction expected after the addition of the Fe-Si alloy is stagnated, and the oxygen concentration in the molten steel after the VOD treatment increases. That is, at present, there is no appropriate method for stably producing high-nitrogen stainless steel having a low oxygen concentration.
【０００５】[0005]
【発明が解決しようとする課題】本発明は、このような
状況に鑑み、ＶＯＤ法のような減圧精錬装置を用いて
も、高窒素濃度で、且つ低酸素濃度の溶鋼を従来より安
定して製造できる高窒素ステンレス溶鋼の溶製方法を提
供することを目的としている。SUMMARY OF THE INVENTION In view of such circumstances, the present invention is capable of stably producing molten steel having a high nitrogen concentration and a low oxygen concentration even when a vacuum refining apparatus such as a VOD method is used. It is an object of the present invention to provide a method for producing a high-nitrogen stainless steel melt that can be produced.
【０００６】[0006]
【課題を解決するための手段】発明者は、上記目的を達
成するため、ＶＯＤ装置を用いた真空下での加窒及び脱
酸について鋭意研究を重ね、その成果を本発明として完
成させた。すなわち、本発明は、減圧精錬装置内の精錬
容器に収容したステンレス溶鋼を、減圧下で脱炭した
後、Ｓｉ又はＳｉ含有合金を添加して脱酸するステンレ
ス鋼の溶製方法において、Ｓｉ又はＳｉ含有合金を添加
後に、前記減圧精錬装置内を、真空度が３０〜１００ｔ
ｏｒｒになるよう減圧すると共に、前記保持容器の上方
及び底部から該溶鋼へ不活性ガスを供給し、該上方又は
該底部の少なくとも一方から供給される不活性ガスは、
窒素ガス又は窒素ガスと窒素以外の不活性ガスとの混合
ガスとして供給し、溶鋼の加窒及び脱酸を同時に行うこ
とを特徴とする高窒素ステンレス鋼の溶製方法である。Means for Solving the Problems In order to achieve the above object, the inventor conducted intensive studies on nitriding and deoxidizing under vacuum using a VOD apparatus, and completed the results as the present invention. That is, the present invention provides a method for producing stainless steel in which a molten stainless steel accommodated in a smelting vessel in a vacuum refining apparatus is decarburized under reduced pressure, and then Si or a Si-containing alloy is added to deoxidize the stainless steel. After the addition of the Si-containing alloy, the inside of the vacuum refining device is evacuated to a degree of vacuum of 30 to 100 t.
While reducing the pressure to orr, an inert gas is supplied to the molten steel from above and from the bottom of the holding container, and the inert gas supplied from at least one of the above and the bottom is:
A high nitrogen stainless steel smelting method characterized in that nitrogen gas or a mixed gas of nitrogen gas and an inert gas other than nitrogen is supplied to simultaneously perform nitriding and deoxidation of molten steel.
【０００７】また、本発明は、前記窒素以外の不活性ガ
スをアルゴン・ガスとすることを特徴とする高窒素ステ
ンレス鋼の溶製方法でもある。本発明によれば、溶鋼中
へ窒素ガス又は窒素と他の不活性ガスの混合ガスを吹き
込むことで窒素濃度をあるレベルに維持したまま、脱酸
できるようになるので、高窒素で且つ低酸素のステンレ
ス溶鋼が製造できるようになる。The present invention is also a method for melting high nitrogen stainless steel, characterized in that the inert gas other than nitrogen is argon gas. According to the present invention, by blowing nitrogen gas or a mixed gas of nitrogen and another inert gas into molten steel, it becomes possible to deoxidize while maintaining the nitrogen concentration at a certain level, so that high nitrogen and low oxygen Stainless steel can be manufactured.
【０００８】[0008]
【発明の実施の形態】以下、発明に至る経緯も含め、本
発明の実施の形態を説明する。本発明が対象とする高窒
素ステンレス鋼は、窒素を４００ｐｐｍ以上含有するス
テンレス鋼であり、フェライト系、オーステナイト系の
いずれでも良い。転炉等の精錬炉で所定炭素濃度にて出
鋼された含クロム溶鋼２を、精錬容器としての取鍋３に
移し、これを図３に示したＶＯＤ真空処理装置１に設置
する。そして、減圧下にて、さらに目標炭素濃度まで脱
炭した後、加窒及び脱酸が行われる。この脱炭処理は、
多くの場合、上吹きランスから酸素又は酸素含有ガスを
吹き付けて行われるが、脱炭量が少なくて良い場合に
は、不活性ガスのみの吹き付けか、あるいは上吹ガスの
吹き付けを行うことなく、専ら減圧による所謂「Ｃ−Ｏ
脱炭」によって行われることもある。DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below, including the circumstances leading up to the invention. The high-nitrogen stainless steel targeted by the present invention is a stainless steel containing 400 ppm or more of nitrogen, and may be any of a ferritic or austenitic stainless steel. The chromium-containing molten steel 2 that has been tapped at a predetermined carbon concentration in a refining furnace such as a converter is transferred to a ladle 3 as a refining vessel, and is set in the VOD vacuum processing apparatus 1 shown in FIG. Then, after further decarburizing to a target carbon concentration under reduced pressure, nitriding and deoxidizing are performed. This decarburization process,
In many cases, it is performed by blowing oxygen or an oxygen-containing gas from the top blowing lance, but if the amount of decarburization may be small, blowing only the inert gas or without blowing the top blowing gas, The so-called “C-O” exclusively by pressure reduction
It is sometimes performed by "decarburization".
【０００９】発明者は、この減圧精錬処理の終了後に、
Ｆｅ−Ｓｉ添加して脱酸する際に、窒素ガスを吹き込む
場合、吹き込まない場合（従来法）、あるいは単に高真
空下に保持する場合について、溶鋼中の窒素及び酸素の
濃度を調査した。まず、図１に、減圧精錬処理終了後の
溶鋼中の窒素濃度と酸素濃度を、上記各場合につき比較
して示す。図１より明らかなように、窒素ガスを上吹き
した場合及び低真空下に維持して窒素ガスの上吹きがな
い場合では、３０〜４０ｔｏｒｒの低真空度下で前記還
元処理を行うため、該処理後の溶鋼中窒素濃度は高く、
目標窒素濃度範囲内を維持することができた。一方、窒
素ガスを吹き込まない従来法では、還元処理を２〜３ｔ
ｏｒｒの高真空度下で行い、溶鋼の平衡の窒素濃度が低
いので、目標窒素濃度よりもかなり低下してしまう。[0009] After the completion of the decompression refining process, the inventor
The nitrogen and oxygen concentrations in the molten steel were investigated when nitrogen gas was blown, when not blown (conventional method), or when simply kept under high vacuum when adding Fe-Si to deoxidize. First, FIG. 1 shows a comparison between the nitrogen concentration and the oxygen concentration in the molten steel after the completion of the vacuum refining process in each case. As is apparent from FIG. 1, when the nitrogen gas is blown upward and when the nitrogen gas is not blown up while being maintained at a low vacuum, the reduction treatment is performed under a low vacuum of 30 to 40 torr. Nitrogen concentration in molten steel after treatment is high,
The target nitrogen concentration was maintained within the target range. On the other hand, in the conventional method in which nitrogen gas is not blown, the reduction treatment is performed for 2 to 3 tons.
The test is performed under a high vacuum of orr and the nitrogen concentration at the equilibrium of the molten steel is low, so that the nitrogen concentration is considerably lower than the target nitrogen concentration.
【００１０】次に、図２に、前記脱炭処理が終了し、Ｆ
ｅ−Ｓｉ合金添加後の酸素濃度を、前記同様に３つの場
合で比較して示す。図２によれば、窒素ガスを上吹きし
た場合と上吹しなかった従来法の場合は、同じような脱
酸挙動を示しており、前記還元処理終了後の酸素濃度
は、目標の５０ｐｐｍ以下を達成していた。一方、低真
空度下で上吹きガス吹き付けが無い場合では、脱酸速度
が低下し、還元処理後の酸素濃度が他の２つの場合に比
較して高く、目標の５０ｐｐｍよりも高くなっていた。Next, FIG. 2 shows that the decarburization process is completed and
The oxygen concentration after the addition of the e-Si alloy is compared and shown in the three cases as described above. According to FIG. 2, the same deoxidation behavior is exhibited in the case where the nitrogen gas is blown upward and the case where the nitrogen gas is not blown upward, and the oxygen concentration after the end of the reduction treatment is equal to or less than the target 50 ppm. Had been achieved. On the other hand, when the top blowing gas was not sprayed under a low vacuum, the deoxidation rate was reduced, and the oxygen concentration after the reduction treatment was higher than the other two cases, which was higher than the target of 50 ppm. .
【００１１】そこで、発明者は、以上の調査結果に基づ
き、低真空度下（３０〜１００ｔｏｒｒ）で、窒素ガス
や不活性ガスを吹込むことにより、鋼中の窒素濃度を高
位に維持したまま、鋼中の酸素濃度を所定の目標濃度ま
で低下させることができると考え、その具体的な実施方
法を本発明としたのである。その実現にあたっては、ま
ず、前述のＶＯＤのような減圧精錬装置において、減圧
下での脱炭処理後に、ＳｉまたはＳｉ含有物質（好まし
くは、Ｆｅ−Ｓｉ）を添加し、前記減圧精錬装置の溶鋼
容器の上方及び底部から溶鋼に不活性ガスを供給する。
この不活性ガスの供給は、溶鋼の脱酸促進と、溶鋼中へ
の窒素の添加の２つの役割を果たす。Therefore, based on the above investigation results, the inventor has blown nitrogen gas or an inert gas under a low vacuum (30 to 100 torr) to maintain the nitrogen concentration in the steel at a high level. The inventors considered that the oxygen concentration in the steel could be reduced to a predetermined target concentration, and made a specific implementation method of the present invention. To achieve this, first, in a vacuum refining apparatus such as the above-described VOD, after decarburization treatment under reduced pressure, Si or a Si-containing substance (preferably Fe-Si) is added, and molten steel of the vacuum refining apparatus is melted. Inert gas is supplied to the molten steel from the top and bottom of the vessel.
The supply of the inert gas plays two roles of promoting the deoxidation of the molten steel and adding nitrogen to the molten steel.
【００１２】この溶鋼の脱酸促進は、溶鋼を撹拌し、添
加されたＳｉが溶鋼に速やかに溶解し、脱酸反応によっ
て生成した非金属介在物が浮上するのを促進すること、
またスラグをも撹拌して、スラグの脱酸をも促進し、処
理後の溶鋼にスラグから酸素が供給されて非金属酸化物
を生成するのを防止する。この溶鋼の撹拌には、容器底
部から溶鋼中に吹き込まれた不活性ガスが主に寄与す
る。撹拌を十分に行わせる観点から、底部からの吹込み
ガス流量は、２ノルマル・リットル／分／トン以上とす
るのが好ましい。また、Ｓｉによる脱酸のみでは、溶鋼
中の溶解酸素は、十分に低下し切らないので、減圧によ
るＣ−Ｏ脱酸も促進する必要がある。後述するように、
溶鋼中に窒素を添加する観点から、減圧装置内真空度
は、目標酸素レベルまで到達できる程度に高真空とする
ことができない。The deoxidation of the molten steel is promoted by agitating the molten steel, rapidly dissolving the added Si in the molten steel, and promoting the floating of nonmetallic inclusions generated by the deoxidation reaction.
Further, the slag is also stirred to promote the deoxidation of the slag, thereby preventing the supply of oxygen from the slag to the molten steel after the treatment to form a nonmetal oxide. The inert gas blown into the molten steel from the bottom of the vessel mainly contributes to the stirring of the molten steel. From the viewpoint of sufficient stirring, the flow rate of the blown gas from the bottom is preferably 2 normal liters / minute / ton or more. Further, only by the deoxidation by Si, the dissolved oxygen in the molten steel is not sufficiently reduced, so it is necessary to promote the CO deoxidation under reduced pressure. As described below,
From the viewpoint of adding nitrogen into the molten steel, the degree of vacuum in the decompression device cannot be made high enough to reach the target oxygen level.
【００１３】そこで、本発明においては、不活性ガスを
上吹することで、溶鋼浴面上のＣＯ分圧を低下させるこ
とで、高真空処理に匹敵する前記「Ｃ−Ｏ脱酸」を可能
とした。この「Ｃ−Ｏ脱酸」促進の観点から、上吹き不
活性ガス流量は、多いほど好ましいが、あまり多くなる
と、溶鋼のスプラッシュが激しくなって、操業を阻害す
る恐れがあるので、０．２Ｎｍ3 ／分・トン以下にとど
めるのが好ましい。なお、この上吹き不活性ガスのガス
種は、ＣＯ分圧を低減できるものであれば、特にガス種
を問うものではない。最も安価で取り扱いが容易なガス
として窒素が好ましく使用できる。Therefore, in the present invention, the above-mentioned "CO deoxidation", which is comparable to high vacuum treatment, is made possible by lowering the partial pressure of CO on the molten steel bath surface by blowing up an inert gas. And From the viewpoint of promoting the "CO deoxidation", the flow rate of the top blown inert gas is preferably as large as possible. It is preferable to keep it at 3 / min / ton or less. The gas type of the top-blown inert gas is not particularly limited as long as it can reduce the CO partial pressure. Nitrogen can be preferably used as the cheapest and easy-to-handle gas.
【００１４】上述したように、本発明では、まず脱酸の
観点から、不活性ガスを容器底部からと容器上方からの
両方から供給することが必須である。次に、溶鋼中への
窒素の添加の観点からは、上述した容器底部からと容器
上方からの不活性ガスのうち少なくとも一方に、窒素ガ
ス又は窒素以外の不活性ガスを使用することによって達
成する。窒素以外の不活性ガスとしては、価格面や取り
扱いの容易さからアルゴンが好適である。As described above, in the present invention, from the viewpoint of deoxidation, it is essential to supply the inert gas from both the bottom of the vessel and the top of the vessel. Next, from the viewpoint of the addition of nitrogen into the molten steel, at least one of the above-described inert gas from the bottom of the container and from above the container is achieved by using a nitrogen gas or an inert gas other than nitrogen. . As an inert gas other than nitrogen, argon is preferred from the viewpoint of cost and ease of handling.
【００１５】溶鋼中への窒素の添加効率の観点からは、
底部から溶鋼中に供給するガスに窒素ガス又は窒素ガス
と窒素以外の不活性ガスを使用すると、ガスと溶鋼の反
応界面積が大きく、且つガスと溶鋼との接触時間を長く
することができるので、有利である。溶鋼中への窒素の
添加は、本発明が減圧精錬装置においてなされる以上、
減圧による気相中への脱窒と、吹き込まれた窒素ガスか
ら溶鋼中への加窒とが競合の上に成り立つ。所定の処理
時間内に十分な加窒を可能とするためには、減圧精錬装
置内の真空度３０〜１００ｔｏｒｒとすることが必要で
ある。これより高真空（すなわち、より低い圧力）で
は、脱窒速度が勝って所定時間内に加窒することが困難
になるためである。一方、上記より低真空（すなわちよ
り高い圧力）では、上述したＣ−Ｃ脱酸が不利になり、
溶鋼中の酸素濃度の低減が困難となるからである。From the viewpoint of the efficiency of adding nitrogen into molten steel,
If nitrogen gas or nitrogen gas and an inert gas other than nitrogen are used as the gas supplied into the molten steel from the bottom, the reaction interface area between the gas and the molten steel is large, and the contact time between the gas and the molten steel can be extended. Is advantageous. The addition of nitrogen into the molten steel, as the present invention is made in a vacuum refining device,
Denitrification into the gas phase by depressurization and nitridation into the molten steel from the blown nitrogen gas are competing. In order to enable sufficient nitriding within a predetermined processing time, it is necessary to set the degree of vacuum in the vacuum refining apparatus to 30 to 100 torr. At a higher vacuum (that is, a lower pressure), the denitrification speed becomes higher, and it becomes difficult to perform nitriding within a predetermined time. On the other hand, at lower vacuums (ie higher pressures), the C-C deoxidation described above is disadvantageous,
This is because it becomes difficult to reduce the oxygen concentration in the molten steel.
【００１６】なお、上吹きガスは、上吹きランス、ある
いはパイプなどを介して溶鋼の浴面上に吹き付けるが、
ガスの底吹きには、溶鋼保持容器（例えば取鍋）の底部
にポーラス・プラグや、鋼製細管あるいはスリットを多
数設けたガス吹き込み用羽口が利用できる。また、本発
明では、上記窒素あるいは不活性ガスの吹込みを、溶鋼
の酸素濃度が５０ｐｐｍ以下まで継続するのが良い。そ
の理由は、例えば、本発明方法によって、溶鋼中の窒素
濃度が製品目標窒素濃度に満たなくても、窒素含有合金
の添加によって不足分の調整が可能であるのに対し、酸
素濃度が５０ｐｐｍより高い場合には非金属介在物が多
くなり、製品の欠陥を引き起こす可能性が高くなるから
である。The top blown gas is blown onto the bath surface of molten steel through a top blow lance or a pipe.
For gas bottom blowing, a porous plug or a gas blowing tuyere provided with a large number of thin steel tubes or slits at the bottom of a molten steel holding container (eg, a ladle) can be used. Further, in the present invention, it is preferable that the blowing of the nitrogen or the inert gas is continued until the oxygen concentration of the molten steel becomes 50 ppm or less. The reason is that, for example, even if the nitrogen concentration in the molten steel is less than the product target nitrogen concentration by the method of the present invention, the shortage can be adjusted by adding a nitrogen-containing alloy, whereas the oxygen concentration is less than 50 ppm. If it is high, the amount of nonmetallic inclusions increases, and the possibility of causing product defects increases.
【００１７】[0017]
【実施例】（実施例１）転炉で粗脱炭を行った溶鋼１６
０トンを取鍋３に出鋼し、その取鍋３をＶＯＤ真空装置
１内に装入し、真空度４０ｔｏｒｒの下で溶鋼２に酸素
を上吹きして、Ｃ：０．０５５重量％及びＣｒ：１８．
２重量％の含クロム溶鋼２とした。しかる後、Ｆｅ−Ｓ
ｉ合金を９５０ｋｇを添加し、装置１内の真空度を４０
ｔｏｒｒにすると共に、上吹き窒素ガスを３０Ｎｍ3 ／
分の流量でランス６の高さ１８００ｍｍで溶鋼面に吹き
付け、２０分間還元処理を行った。また、その際、底吹
きガス５としては、アルゴン・ガス５００Ｎリットル／
分、窒素ガス５００Ｎリットル／分の混合ガスも同時に
使用した。EXAMPLES (Example 1) Molten steel 16 subjected to rough decarburization in a converter
0 tons was tapped into a ladle 3, and the ladle 3 was charged into a VOD vacuum apparatus 1, and oxygen was blown upward to the molten steel 2 under a degree of vacuum of 40 torr, so that C: 0.055% by weight and Cr: 18.
Chromium-containing molten steel 2 of 2% by weight was obtained. After a while, Fe-S
950 kg of the i-alloy was added, and the degree of vacuum in the apparatus 1 was increased to 40
torr and blown nitrogen gas at 30 Nm 3 /
The lance 6 was sprayed onto the molten steel surface at a height of 1800 mm at a flow rate of 1 minute, and a reduction treatment was performed for 20 minutes. At this time, the bottom blown gas 5 is argon gas 500Nl /
And a mixed gas of 500 Nl / min of nitrogen gas at the same time.
【００１８】その結果、Ｃ：０．０４０重量％、Ｃｒ１
８．３重量％、Ｓｉ：０．３５重量％、Ｏ：４５ｐｐ
ｍ、Ｎ：５２０ｐｐｍのステンレス溶鋼を得ることがで
きた。 （実施例２）転炉で粗脱炭を行った溶鋼１６０ｔｏｎを
取鍋３に出鋼し、その取鍋３をＶＯＤ真空装置に装入
し、真空度６０ｔｏｒｒの下で酸素吹錬を行い、Ｃ：
０．０６重量％、Ｃｒ：１８．１重量％の含クロム溶鋼
２を得た。しかる後、Ｆｅ−Ｓｉ合金を１０００ｋｇを
添加し、装置１内の真空度を３５ｔｏｒｒにすると共
に、上吹きガスとして窒素ガス及びアルゴン・ガスをそ
れぞれ１０Ｎｍ3 ／分混合したものを、ランス６の高さ
１８００ｍｍで溶鋼２面に吹き付け、２５分間還元処理
を行った。また、その際、底吹きガス５としては、実施
例１と同様に、アルゴン・ガスを５００Ｎリットル／
分、窒素ガスを５００Ｎリットル／分の混合ガスとし
た。As a result, C: 0.040% by weight, Cr1
8.3% by weight, Si: 0.35% by weight, O: 45pp
m, N: 520 ppm of molten stainless steel could be obtained. (Example 2) 160 tons of molten steel that had been roughly decarburized in a converter were tapped into a ladle 3, the ladle 3 was charged into a VOD vacuum device, and oxygen was blown at a degree of vacuum of 60 torr. C:
A chromium-containing molten steel 2 of 0.06% by weight and Cr: 18.1% by weight was obtained. Thereafter, 1000 kg of an Fe-Si alloy was added, the degree of vacuum in the apparatus 1 was set to 35 torr, and nitrogen gas and argon gas were mixed at 10 Nm 3 / min each as an upper blowing gas. The molten steel was sprayed at a thickness of 1800 mm on two surfaces and subjected to a reduction treatment for 25 minutes. At this time, as the bottom blow gas 5, as in the first embodiment, argon gas was supplied at 500 Nl /
And nitrogen gas as a mixed gas of 500 Nl / min.
【００１９】その結果、Ｃ：０．０４８重量％、Ｃｒ：
１８．２重量％、Ｓｉ：０．３８重量％、Ｏ：４７ｐｐ
ｍ、Ｎ：５００ｐｐｍのステンレス溶鋼を得ることがで
きた。As a result, C: 0.048% by weight, Cr:
18.2% by weight, Si: 0.38% by weight, O: 47pp
m, N: 500 ppm of molten stainless steel could be obtained.
【００２０】[0020]
【発明の効果】以上述べたように、本発明により、ＶＯ
Ｄ真空装置を用いて、高窒素濃度で、且つ低酸素濃度の
溶鋼を従来より安定して製造できるようになった。As described above, according to the present invention, VO
By using a D vacuum apparatus, molten steel having a high nitrogen concentration and a low oxygen concentration can be manufactured more stably than before.
【図１】ＶＯＤ減圧精錬装置内で溶鋼をＦｅ−Ｓｉ合金
で還元処理した後の鋼中酸素濃度と窒素濃度との関係を
示す図である。FIG. 1 is a view showing a relationship between oxygen concentration and nitrogen concentration in steel after reducing molten steel with an Fe—Si alloy in a VOD vacuum refining apparatus.
【図２】図１と同じ還元処理中の脱酸挙動を示す図であ
る。FIG. 2 is a view showing the deoxidation behavior during the same reduction treatment as in FIG.
【図３】ＶＯＤ減圧精錬装置を示す縦断面図である。FIG. 3 is a longitudinal sectional view showing a VOD vacuum refining device.
１ ＶＯＤ減圧精錬装置 ２ 含クロム溶鋼（溶鋼） ３ 取鍋 ４ ランス 1 VOD vacuum refining equipment 2 Chromium-containing molten steel (molten steel) 3 Ladle 4 Lance
───────────────────────────────────────────────────── フロントページの続き (72)発明者 竹内 秀次 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 (72)発明者 反町 健一 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shuji Takeuchi 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel (72) Inventor Kenichi Sorimachi 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Research Institute
Claims (2)
テンレス溶鋼を、減圧下で脱炭した後、Ｓｉ又はＳｉ含
有合金を添加して脱酸するステンレス鋼の溶製方法にお
いて、 Ｓｉ又はＳｉ含有合金を添加後に、前記減圧精錬装置内
を、真空度が３０〜１００ｔｏｒｒになるよう減圧する
と共に、前記保持容器の上方及び底部から該溶鋼へ不活
性ガスを供給し、該上方又は該底部の少なくとも一方か
ら供給される不活性ガスは、窒素ガス又は窒素ガスと窒
素以外の不活性ガスとの混合ガスとして供給し、溶鋼の
加窒及び脱酸を同時に行うことを特徴とする高窒素ステ
ンレス鋼の溶製方法。1. A method for producing stainless steel, comprising: decarburizing a molten stainless steel contained in a smelting vessel in a vacuum refining apparatus under reduced pressure; and adding Si or an Si-containing alloy to deoxidize the molten steel. After adding the containing alloy, the inside of the vacuum refining apparatus is reduced in pressure to a degree of vacuum of 30 to 100 torr, and an inert gas is supplied to the molten steel from above and from the bottom of the holding vessel, and the inert gas is supplied to the above or below the bottom. Inert gas supplied from at least one of them is supplied as nitrogen gas or a mixed gas of nitrogen gas and an inert gas other than nitrogen, and high-nitrogen stainless steel characterized by simultaneously performing nitriding and deoxidation of molten steel. Smelting method.
ガスとすることを特徴とする請求項１記載の高窒素ステ
ンレス鋼の溶製方法。2. An inert gas other than nitrogen is argon
2. The method according to claim 1, wherein the gas is a gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07972598A JP3843589B2 (en) | 1998-03-26 | 1998-03-26 | Melting method of high nitrogen stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07972598A JP3843589B2 (en) | 1998-03-26 | 1998-03-26 | Melting method of high nitrogen stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11279624A true JPH11279624A (en) | 1999-10-12 |
| JP3843589B2 JP3843589B2 (en) | 2006-11-08 |
Family
ID=13698189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07972598A Expired - Lifetime JP3843589B2 (en) | 1998-03-26 | 1998-03-26 | Melting method of high nitrogen stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3843589B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100429158B1 (en) * | 1999-10-20 | 2004-04-28 | 주식회사 포스코 | Method for decarburizing austenite stainless steel |
| JP2007138206A (en) * | 2005-11-16 | 2007-06-07 | Jfe Steel Kk | Method for highly purifying molten metal |
| WO2014142699A1 (en) * | 2013-03-13 | 2014-09-18 | Parshin Vladimir Andreevich | Method for double alloying and nanophase modification of steel by atomic nitrogen |
| RU2660797C1 (en) * | 2017-04-10 | 2018-07-09 | Публичное Акционерное Общество "Новолипецкий металлургический комбинат" | Wire for out-of-furnace treatment of metallurgical melts |
| KR102482746B1 (en) * | 2021-10-19 | 2022-12-29 | (주)대창솔루션 | Method for high nitrogen stainless steel |
-
1998
- 1998-03-26 JP JP07972598A patent/JP3843589B2/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100429158B1 (en) * | 1999-10-20 | 2004-04-28 | 주식회사 포스코 | Method for decarburizing austenite stainless steel |
| JP2007138206A (en) * | 2005-11-16 | 2007-06-07 | Jfe Steel Kk | Method for highly purifying molten metal |
| WO2014142699A1 (en) * | 2013-03-13 | 2014-09-18 | Parshin Vladimir Andreevich | Method for double alloying and nanophase modification of steel by atomic nitrogen |
| CN105555975A (en) * | 2013-03-13 | 2016-05-04 | 公司新利佩茨克钢铁 | Method for double alloying and nanophase modification of steel by atomic nitrogen |
| US9523138B2 (en) | 2013-03-13 | 2016-12-20 | Otkrytoe Aktsionernoe Obshhestvo Novolipetskij Metallurgicheskij Kombinat | Method for double dislocation alloying and nanophase modification of steel by atomic nitrogen |
| CN105555975B (en) * | 2013-03-13 | 2017-06-09 | 公开股票社会新利佩茨克冶金卡特尔 | The method that dual alloying is mutually modified with nanometer is carried out to steel by Nitrogen Atom |
| RU2639749C2 (en) * | 2013-03-13 | 2017-12-22 | Публичное Акционерное Общество "Новолипецкий металлургический комбинат" | Method of double doping and nanophase modification of steel by atomic nitrogen |
| RU2660797C1 (en) * | 2017-04-10 | 2018-07-09 | Публичное Акционерное Общество "Новолипецкий металлургический комбинат" | Wire for out-of-furnace treatment of metallurgical melts |
| KR102482746B1 (en) * | 2021-10-19 | 2022-12-29 | (주)대창솔루션 | Method for high nitrogen stainless steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3843589B2 (en) | 2006-11-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2575827B2 (en) | Manufacturing method of ultra low carbon steel for continuous casting with excellent cleanliness | |
| JP3903580B2 (en) | Method of melting high cleanliness steel | |
| JP5428447B2 (en) | Method for refining molten steel in RH vacuum degassing equipment | |
| JP3843589B2 (en) | Melting method of high nitrogen stainless steel | |
| JP2767674B2 (en) | Refining method of high purity stainless steel | |
| JPS60234916A (en) | Manufacture of stainless steel containing low nitrogen | |
| JPH11106823A (en) | Method for refining extra-low carbon and extra-low nitrogen stainless steel | |
| JPH0153329B2 (en) | ||
| JPH06306442A (en) | Production of extra low sulfur steel | |
| JPS63143216A (en) | Melting method for extremely low carbon and low nitrogen steel | |
| CN114774619B (en) | Low-nitrogen high-carbon chromium bearing steel and production method thereof | |
| JP2000212641A (en) | High speed vacuum refining of molten steel | |
| JPH0841530A (en) | Production of low aluminum and low sulfur stainless steel | |
| JP7468567B2 (en) | Method for denitrification of molten steel | |
| JP4352898B2 (en) | Method of melting high cleanliness steel | |
| JPH11140530A (en) | Production of ultra-low nitrogen stainless steel | |
| JP2001172715A (en) | Method of manufacturing molten ultra-low carbon stainless steel | |
| JPS6337162B2 (en) | ||
| JPH08104914A (en) | Highly efficient production of high purity molten stainless steel | |
| JPH0941028A (en) | Production of high purity ultra-low carbon steel | |
| JP3127733B2 (en) | Manufacturing method of ultra clean ultra low carbon steel | |
| JP4020125B2 (en) | Method of melting high cleanliness steel | |
| JP2962163B2 (en) | Melting method of high clean ultra low carbon steel | |
| JP3757435B2 (en) | Method for decarburizing and refining chromium-containing molten steel | |
| JPH08302419A (en) | Refining method of molten steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050301 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20060714 |
|
| 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: 20060725 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20060807 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090825 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100825 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110825 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120825 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120825 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130825 Year of fee payment: 7 |
|
| EXPY | Cancellation because of completion of term |