JPH10298631A - Method for melting clean steel - Google Patents
Method for melting clean steelInfo
- Publication number
- JPH10298631A JPH10298631A JP9108843A JP10884397A JPH10298631A JP H10298631 A JPH10298631 A JP H10298631A JP 9108843 A JP9108843 A JP 9108843A JP 10884397 A JP10884397 A JP 10884397A JP H10298631 A JPH10298631 A JP H10298631A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- steel
- concentration
- flux
- refining
- 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
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】[0001]
【発明の属する技術分野】本発明は、酸素含有量が微量
で、かつＡｌ2 Ｏ3 系介在物の少ない清浄鋼の溶製方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a clean steel having a small amount of oxygen and a small amount of Al 2 O 3 inclusions.
【０００２】[0002]
【従来の技術】最近、鋼材の品質に対する要求はますま
す厳しく、かつ多様化する傾向にあり、現状におけるよ
りも一層高度な清浄性を有する鋼の製造技術の開発が必
要不可欠な状況にある。2. Description of the Related Art In recent years, the demands for the quality of steel materials have been increasingly severe and diversified, and it is indispensable to develop steel production technology having higher cleanliness than the current state.
【０００３】例えば、清浄性に優れていることが要求さ
れる軸受鋼では、Ａｌ2 Ｏ3 系介在物が少なく、特に粒
径が２０μｍ以上の大型の介在物が極めて少ないことが
必要とされる。大型のＡｌ2 Ｏ3 系介在物が含有されて
いると、鋼の転動疲労寿命が著しく低下するからであ
る。[0003] For example, in a bearing steel which is required to have excellent cleanliness, it is necessary that the number of Al 2 O 3 -based inclusions is small, and in particular, that the size of large inclusions having a particle size of 20 μm or more is extremely small. . This is because, when large Al 2 O 3 inclusions are contained, the rolling fatigue life of steel is significantly reduced.
【０００４】この軸受鋼は、一般的には、特開昭６２−
２９４１５０号公報に開示されているように、精錬容器
内の溶鋼に対し、容器底部から不活性ガスを吹き込んで
溶鋼を撹拌しつつ精錬用フラックスを供給するとともに
上部から酸化性ガスを吹付けて酸化精錬を行い、スラグ
を除去した後、不活性ガス撹拌を行いつつ塩基性スラグ
の存在下で電極加熱により溶鋼の温度を調整しながら還
元精錬を行い、その後真空脱ガス処理を行うことにより
製造される。しかし、この方法では、溶鋼中の全酸素濃
度（以下、「溶鋼中の〔Ｏ〕濃度」と記す）が高い段階
でＡｌ（アルミニウム）を添加して脱酸を行うので、粒
径が２０μｍ以上の大型のＡｌ2 Ｏ3 系介在物が精錬後
の溶鋼中に残留しやすい。[0004] This bearing steel is generally disclosed in
As disclosed in Japanese Patent No. 294150, an inert gas is blown from the bottom of the vessel to the molten steel in the refining vessel to supply the flux for refining while stirring the molten steel, and oxidizing gas is blown from the top to oxidize the molten steel. After refining and removing slag, it is manufactured by performing reductive refining while adjusting the temperature of molten steel by heating the electrode in the presence of basic slag while stirring with inert gas, and then performing vacuum degassing. You. However, in this method, Al (aluminum) is added and deoxidized at a stage where the total oxygen concentration in the molten steel (hereinafter, referred to as “[O] concentration in the molten steel”) is high, so that the particle size is 20 μm or more. Al 2 O 3 inclusions large tends to remain in the molten steel after refining.
【０００５】これに対して、まず、真空精錬装置で
〔Ｃ〕（溶鋼中の炭素）による予備脱酸を行い、溶鋼中
の〔Ｏ〕濃度を低くしてからＡｌを添加して脱酸する方
法が特開平５−３３１５２３号公報に開示されている。
この方法によって、Ａｌ2 Ｏ3 粒子数が少なく、かつ、
２０μｍ以上の大型のＡｌ2 Ｏ3 を著しく減少させた溶
鋼を得ることができるとされている。しかしながら、こ
の方法では約３０分を要する真空脱ガス処理を行うの
で、その後のフラックス精錬を含めた全処理時間が８０
分以上かかり、生産性が低く、製造コストが高くならざ
るをえない。[0005] On the other hand, first, preliminary deoxidation by [C] (carbon in molten steel) is performed by a vacuum refining apparatus to lower the [O] concentration in molten steel, and then Al is added to deoxidize. The method is disclosed in JP-A-5-331523.
By this method, the number of Al 2 O 3 particles is small, and
It is said that it is possible to obtain molten steel in which Al 2 O 3 having a size of 20 μm or more is significantly reduced. However, in this method, a vacuum degassing process that takes about 30 minutes is performed, so that the total processing time including the flux refining is 80 hours.
It takes more than a minute, the productivity is low, and the manufacturing cost has to be high.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上記従来の
技術における問題を解決し、特に軸受鋼に要求される、
酸素濃度が低く、しかも大型のＡｌ2 Ｏ3 系介在物の発
生が極めて少ない優れた清浄性を有する鋼を、簡便に、
かつ高い生産性をもって効率よく溶製することができる
方法を提供することを課題としてなされたものである。SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and is particularly required for bearing steel.
Oxygen concentration is low, and the generation of large Al 2 O 3 -based inclusions is extremely low.
Another object of the present invention is to provide a method capable of efficiently producing smelting with high productivity.
【０００７】[0007]
【課題を解決するための手段】本発明者は、上記の目的
を達成するために検討を重ねた結果、溶鋼をＡｌ以外の
元素により脱酸し、非脱酸剤フラックス吹き込みにより
溶鋼中の〔Ｏ〕濃度を低下させた後にＡｌを添加するこ
とが有効であることを確認し、本発明をなすに至った。Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventor deoxidized molten steel with an element other than Al, and injected non-deoxidizing agent flux into the molten steel. O] It was confirmed that adding Al after reducing the concentration was effective, and the present invention was accomplished.
【０００８】本発明の要旨は、下記（１）および（２）
の清浄鋼の溶製方法にある。The gist of the present invention is as follows (1) and (2)
Smelting method of clean steel.
【０００９】（１）Ａｌ以外の元素により脱酸した溶鋼
に、表面のスラグを除去した後、ＣａＯ、ＣａＦ2 、Ｍ
ｇＯおよびＣａＣＯ3 のうちの一種以上を含む非脱酸剤
フラックスを吹き込んで予備脱酸を行い、次いで、フラ
ックス精錬を行うとともにそのフラックス精錬の間にＡ
ｌを添加して脱酸することを特徴とする清浄鋼の溶製方
法。(1) After removing slag on the surface of molten steel deoxidized by an element other than Al, CaO, CaF 2 , M
Pre-deoxidation is performed by blowing a non-deoxidizing agent flux containing at least one of gO and CaCO 3 , and then a flux refining is performed and A is added during the flux refining.
1. A method for smelting clean steel, which comprises adding 1 to deoxidize.
【００１０】（２）非脱酸剤フラックス吹き込み後の溶
鋼中の〔Ｏ〕濃度を２０ｐｐｍ以下とし、かつ、スラグ
中の（ＦｅＯ＋ＭｎＯ）濃度を１重量％以下とする上記
（１）に記載の清浄鋼の溶製方法。(2) The cleaning according to the above (1), wherein the [O] concentration in the molten steel after blowing the non-deoxidizing agent flux is 20 ppm or less and the (FeO + MnO) concentration in the slag is 1% by weight or less. Steel melting method.
【００１１】ここでいう溶鋼中の〔Ｏ〕濃度とは、溶鋼
に固溶しているフリーの酸素の他に、ＳｉＯ2 、Ｍｎ
Ｏ、Ｃｒ2 Ｏ3 、ＦｅＯなどの酸化物を形成する酸素を
含む全酸素濃度である。また、スラグ中の（ＦｅＯ＋Ｍ
ｎＯ）濃度とは、非脱酸剤フラックスの吹き込みにより
生成するスラグ（以下、これを、「取鍋スラグ」または
単に「スラグ」という）に含まれるＦｅＯおよびＭｎＯ
の合計量を取鍋スラグの全量に対する重量％で表した濃
度である。The [O] concentration in the molten steel referred to herein means not only free oxygen dissolved in the molten steel, but also SiO 2 , Mn.
This is the total oxygen concentration including oxygen that forms oxides such as O, Cr 2 O 3 , and FeO. In addition, (FeO + M
nO) concentration refers to FeO and MnO contained in slag (hereinafter referred to as “ladle slag” or simply “slag”) generated by blowing a non-oxidizing agent flux.
Is the concentration expressed in% by weight with respect to the total amount of ladle slag.
【００１２】[0012]
【発明の実施の形態】以下に、本発明（上記（１）およ
び（２）の発明）の清浄鋼の溶製方法について詳細に説
明する。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a clean steel of the present invention (the inventions of the above (1) and (2)) will be described in detail.
【００１３】図１は、上記（１）の発明の清浄鋼の溶製
方法のフローを前記の従来技術と対比して示した図であ
る。なお、図１における従来技術とは、前記の特開昭
６２−２９４１５０号公報に記載されている方法であ
り、従来技術とは、特開平５−３３１５２３号公報に
記載の方法である。FIG. 1 is a diagram showing the flow of the method for producing clean steel of the invention (1) in comparison with the above-mentioned conventional technology. The prior art in FIG. 1 is a method described in the above-mentioned Japanese Patent Application Laid-Open No. 62-294150, and the conventional technology is a method described in Japanese Patent Application Laid-Open No. 5-331523.
【００１４】図示するように、（１）の発明の方法（図
では、本発明方法と表示）では、Ａｌ添加を行わず、Ａ
ｌ以外の元素により脱酸した溶鋼をさらに精錬処理する
際に、例えば、出鋼後の溶鋼を取鍋に受け、溶鋼表面に
浮上する転炉スラグを除去した後、非脱酸剤からなるフ
ラックスを吹き込んで予備脱酸を行う。次いで、フラッ
クス精錬を行って清浄鋼とする。なお、このフラックス
精錬中にＡｌを添加して脱酸を行うと同時に、溶鋼中の
Ａｌ濃度（以下、「溶鋼中の〔Ａｌ〕濃度」と記す）を
調整する。As shown in the figure, in the method (1) of the present invention (in the figure, the method is referred to as the present invention), A
When the molten steel deoxidized by an element other than l is further refined, for example, the molten steel after tapping is placed in a ladle, the converter slag floating on the molten steel surface is removed, and then a flux comprising a non-deoxidizing agent To perform preliminary deoxidation. Next, flux refining is performed to obtain clean steel. During the flux refining, Al is added to perform deoxidation, and at the same time, the Al concentration in the molten steel (hereinafter referred to as “[Al] concentration in the molten steel”) is adjusted.
【００１５】Ａｌ非添加とするのは、出鋼後の溶鋼は
〔Ｏ〕濃度が比較的高く、Ａｌを添加すると、２０μｍ
以上の大型のＡｌ2 Ｏ3 系介在物が発生し、精錬処理後
も残留するからである。The reason for not adding Al is that the molten steel after tapping has a relatively high [O] concentration.
This is because such large Al 2 O 3 inclusions are generated and remain after the refining process.
【００１６】出鋼後、溶鋼表面のスラグを除去するの
は、転炉での吹錬中に生じた低級酸化物（例えば、Ｆｅ
Ｏ、ＭｎＯ、ＳｉＯ2 など）による溶鋼の再酸化を防止
するためである。出鋼時に取鍋内に流入するスラグの量
を極力少なくすることはもちろんであるが、混入したス
ラグを、例えばスラグドラッガー等を用いて完全に排除
する。After tapping, the slag on the surface of the molten steel is removed by lower oxide (eg, Fe) generated during blowing in a converter.
O, it is to prevent MnO, the reoxidation of the molten steel by SiO 2, etc.). Of course, the amount of slag flowing into the ladle during tapping is reduced as much as possible, but the mixed slag is completely removed using, for example, a slag dragger.
【００１７】次いで、非脱酸剤フラックスの吹き込みに
よる予備脱酸で、溶鋼中の〔Ｏ〕濃度を低下させる。こ
れは、〔Ｏ〕濃度の低い状態でＡｌ添加を行うと、溶鋼
中に生成するＡｌ2 Ｏ3 粒子数が少なくなり、また、粒
子径が２０μｍ以上の大型のＡｌ2 Ｏ3 粒子の生成も著
しく減少するからである。Next, the [O] concentration in the molten steel is reduced by preliminary deoxidation by blowing a non-deoxidizing agent flux. This, when the Al added in a state of low [O] concentration, Al 2 O 3 number of particles to be generated in the molten steel is reduced, also produce a particle size of Al 2 O 3 particles or larger 20μm This is because it is significantly reduced.
【００１８】この予備脱酸で非脱酸剤フラックスを吹き
込む方法を採るのは、非脱酸剤フラックスを使用するこ
とによって、脱酸生成物の発生を防止しつつ、吹き込み
フラックスが浮上する際に溶鋼中に既に存在する脱酸生
成物を捕捉してそれとともに浮上することを利用して、
溶鋼中の〔Ｏ〕濃度を低減するためである。すなわち、
前述した溶鋼に固溶しているフリーの酸素および酸化物
を形成する酸素のうちの後者（つまり、ＳｉＯ2 、Ｍｎ
Ｏ、Ｃｒ2 Ｏ3 、ＦｅＯなどの酸化物）が除去され、そ
の結果、溶鋼中の〔Ｏ〕濃度が低下する。すなわち、取
鍋スラグとして浮上しきれていない溶鋼中のＦｅＯ、Ｍ
ｎＯ、ＳｉＯ2 などが除去される。The method of blowing the non-deoxidizing agent flux in this preliminary deoxidation is to use the non-deoxidizing agent flux to prevent the generation of deoxidized products and to prevent the generation of the deoxidized product when the blown-in flux rises. Utilizing the fact that deoxidation products already existing in molten steel are captured and floated with it,
This is for reducing the [O] concentration in the molten steel. That is,
The latter (ie, SiO 2 , Mn) of free oxygen dissolved in the molten steel and oxygen forming oxides described above.
O, Cr 2 O 3 , oxides such as FeO) are removed, and as a result, the [O] concentration in the molten steel decreases. In other words, FeO, M in molten steel that has not yet emerged as ladle slag
nO, SiO 2 and the like are removed.
【００１９】非脱酸剤フラックスとしては、ＣａＯ、Ｃ
ａＦ2 、ＭｇＯおよびＣａＣＯ3 のうちの一種以上を含
むフラックスを用いる。例えば、実施例で用いたＣａＯ
およびＣａＦ2 からなるフラックス等が好適である。Ｃ
ａＦ2 を加えるのは、吹き込み後の生成スラグの融点を
下げて、浮上した介在物を吸着しやすくするためで、組
成としては、ＣａＯ：５０〜６０重量％、ＣａＦ2 ：４
０〜５０重量％のものが好ましい。また、吹き込み時の
粉末の粒径は、溶鋼中に分散させる必要があるため、１
μｍ以下が望ましい。As the non-oxidizing agent flux, CaO, C
A flux containing one or more of aF 2 , MgO and CaCO 3 is used. For example, the CaO used in the examples
And a flux composed of CaF 2 and the like. C
The reason for adding aF 2 is to lower the melting point of the formed slag after blowing and to make it easier to adsorb the floating inclusions. The composition is as follows: CaO: 50 to 60% by weight, CaF 2 : 4
Those having 0 to 50% by weight are preferred. In addition, the particle size of the powder at the time of blowing needs to be dispersed in molten steel.
μm or less is desirable.
【００２０】非脱酸剤フラックスの吹き込みは、後述す
る実施例に示すように、上吹きまたは横吹きランスを用
いて行うのが好ましい。なお、フラックス吹き込み時は
シュノーケルを用いて溶鋼の飛散および溶鋼の大気との
接触による再酸化を防止する。The blowing of the non-deoxidizing agent flux is preferably performed by using a top-blowing or side-blowing lance, as will be described later in Examples. At the time of injecting flux, a snorkel is used to prevent scattering of the molten steel and reoxidation of the molten steel due to contact with the atmosphere.
【００２１】吹き込み量および吹き込み処理時間は、処
理前の溶鋼中の〔Ｏ〕濃度のレベル等に応じて適宜定め
ればよい。通常は、吹き込み量は２〜５ｋｇ／処理ｔ、
処理時間は約５分とするのがよい。The amount of blowing and the duration of the blowing treatment may be appropriately determined according to the level of the [O] concentration in the molten steel before the treatment. Normally, the blowing amount is 2 to 5 kg / t,
The processing time is preferably about 5 minutes.
【００２２】上記の非脱酸剤フラックスの吹き込みによ
る予備脱酸を行った後、フラックス精錬を行い、その間
にＡｌを添加する。フラックス精錬では取鍋スラグ中の
（ＦｅＯ＋ＭｎＯ）濃度の増加は起こらないので、溶鋼
に添加されたＡｌとＦｅＯおよびＭｎＯとの反応による
Ａｌの再酸化が抑制される。After preliminary deoxidation by blowing the above-mentioned non-deoxidizing agent flux, flux refining is performed, during which Al is added. Since the (FeO + MnO) concentration in the ladle slag does not increase in the flux refining, the reoxidation of Al due to the reaction between Al added to the molten steel and FeO and MnO is suppressed.
【００２３】フラックス精錬は、通常行われている方法
により実施すればよい。例えば、フラックスとしては、
ＣａＯ−ＳｉＯ2 −ＣａＦ2 系、ＣａＯ−ＳｉＯ2 −Ａ
ｌ2Ｏ3 系、ＣａＯ−Ａｌ2 Ｏ3 −ＣａＦ2 系等のフラ
ックスを用い、電極加熱式精錬炉（ＶＡＤ装置）により
加熱しつつＡｒを吹き込んで溶鋼を攪拌する方法、ある
いは取鍋電極加熱式精錬炉（ＬＦ装置）により加熱しつ
つ、Ａｒを吹き込んで溶鋼を撹拌する方法等により行
う。The flux refining may be carried out by a commonly used method. For example, as flux
CaO-SiO 2 -CaF 2 system, CaO-SiO 2 -A
Using a flux of l 2 O 3 system, CaO-Al 2 O 3 -CaF 2 system, etc., a method of stirring molten steel by blowing Ar while heating in an electrode heating type refining furnace (VAD apparatus), or ladle electrode heating The method is carried out by a method of stirring Ar by blowing Ar while heating the steel by a refining furnace (LF device).
【００２４】このフラックス精錬中に、ショットＡｌ、
フレークＡｌ等のＡｌを添加する。これによって、溶鋼
中に残存する酸素をほぼ完全に除去することができ、か
つ、溶鋼中の〔Ａｌ〕濃度を必要とされる濃度に調整す
ることができる。During the flux refining, shot Al,
Al such as flake Al is added. As a result, oxygen remaining in the molten steel can be almost completely removed, and the [Al] concentration in the molten steel can be adjusted to a required concentration.
【００２５】上記（１）の発明の方法により、溶鋼中の
〔Ｏ〕濃度が低く、かつ、大型のＡｌ2 Ｏ3 系介在物の
発生が少ない優れた清浄性を有する鋼を製造することが
できる。According to the method of the present invention (1), it is possible to produce a steel having a low [O] concentration in molten steel and having excellent cleanliness with little generation of large Al 2 O 3 inclusions. it can.
【００２６】しかも、この方法によれば、非脱酸剤フラ
ックスの吹き込みによる予備脱酸処理に要する時間は約
５分で、前記図１に示した従来技術の真空脱ガス処理
で約３０分を要するのに比べて格段に短く、処理時間を
大幅に短縮して生産性を向上させ、コスト低減を図るこ
とができる。また、真空精錬装置等を使用しないので、
設備コスト面でも大幅な改善が見込まれる。Moreover, according to this method, the time required for the preliminary deoxidation treatment by blowing in the non-deoxidizing agent flux is about 5 minutes, and about 30 minutes in the conventional vacuum degassing treatment shown in FIG. The processing time is much shorter than required, and the processing time can be significantly reduced to improve productivity and reduce costs. Also, since no vacuum refining equipment is used,
Significant improvements in equipment costs are also expected.
【００２７】前記（２）の発明の清浄鋼の溶製方法は、
（１）の発明の方法において、非脱酸剤フラックス吹き
込み後の溶鋼中の〔Ｏ〕濃度を２０ｐｐｍ以下とし、か
つ、取鍋スラグ中の（ＦｅＯ＋ＭｎＯ）濃度を１重量％
以下とする方法である。[0027] The method for smelting clean steel of the invention (2) is as follows.
In the method of the invention of (1), the [O] concentration in the molten steel after blowing the non-oxidizing agent flux is set to 20 ppm or less, and the (FeO + MnO) concentration in the ladle slag is 1% by weight.
The following method is used.
【００２８】溶鋼中の〔Ｏ〕濃度と取鍋スラグ中の（Ｆ
ｅＯ＋ＭｎＯ）濃度をこのように規定するのは、溶鋼中
の〔Ｏ〕濃度が低く、かつ、大型のＡｌ2 Ｏ3 系介在物
の発生が少ない優れた清浄性を有する鋼を安定して製造
するためである。〔Ｏ〕濃度が２０ｐｐｍを超え、ある
いはスラグ中の（ＦｅＯ＋ＭｎＯ）濃度が１重量％を超
えると、非脱酸剤フラックスの吹き込みに続いて行うフ
ラックス精錬中にＡｌを添加して脱酸する際、添加した
Ａｌが溶鋼中の酸素やスラグ中のＦｅＯおよびＭｎＯと
反応し、再酸化して、Ａｌ2 Ｏ3 粒子の生成量が増加
し、２０μｍ以上の大型のＡｌ2 Ｏ3 系介在物が発生し
やすくなる。[O] concentration in molten steel and (F) in ladle slag
The reason for defining the (eO + MnO) concentration in this manner is to stably produce a steel having a low [O] concentration in molten steel and having excellent cleanliness with little generation of large Al 2 O 3 inclusions. That's why. When the [O] concentration exceeds 20 ppm or the (FeO + MnO) concentration in the slag exceeds 1% by weight, when deoxidizing by adding Al during flux refining performed following the blowing of the non-deoxidizing agent flux, The added Al reacts with oxygen in the molten steel and FeO and MnO in the slag and re-oxidizes, increasing the amount of Al 2 O 3 particles generated and generating large Al 2 O 3 -based inclusions of 20 μm or more. Easier to do.
【００２９】なお、溶鋼中の〔Ｏ〕濃度については、溶
鋼中に直接測酸プローブ（ＯＸＰ）を浸漬して測定する
ことにより確認し、取鍋スラグ中の（ＦｅＯ＋ＭｎＯ）
濃度については、これまでの処理実績に基づいて推定す
る。なお、（ＦｅＯ＋ＭｎＯ）濃度は、処理後に分析を
行って確認する。The [O] concentration in the molten steel was confirmed by immersing an acid measuring probe (OXP) directly in the molten steel and measuring it, and the (FeO + MnO) in the ladle slag was confirmed.
The density is estimated based on the processing results so far. The (FeO + MnO) concentration is confirmed by performing analysis after the treatment.
【００３０】図２は上記の溶鋼中の〔Ｏ〕濃度と取鍋ス
ラグ中の（ＦｅＯ＋ＭｎＯ）濃度との関係を示す図であ
る。この図は、実際のフラックス精錬操業中における調
査データにより得られたものであるが、溶鋼中の〔Ｏ〕
濃度と取鍋スラグ中の（ＦｅＯ＋ＭｎＯ）濃度は同図中
に示した二つの曲線に挟まれた領域内に入ると考えられ
る。この図から、優れた清浄性を有する鋼を安定して製
造するためには、溶鋼中の〔Ｏ〕濃度を２０ｐｐｍ以下
とするだけではなく、スラグ中の（ＦｅＯ＋ＭｎＯ）濃
度を１重量％以下とすることが必要であることがわか
る。FIG. 2 is a diagram showing the relationship between the [O] concentration in the molten steel and the (FeO + MnO) concentration in the ladle slag. This figure was obtained from survey data during the actual flux refining operation.
It is considered that the concentration and the (FeO + MnO) concentration in the ladle slag fall within the region between the two curves shown in FIG. From this figure, in order to stably produce steel having excellent cleanliness, not only the [O] concentration in the molten steel is set to 20 ppm or less, but also the (FeO + MnO) concentration in the slag is set to 1% by weight or less. It turns out that it is necessary to do.
【００３１】上記（２）の発明の方法によれば、酸素濃
度が低く、かつ、大型のＡｌ2 Ｏ3系介在物の発生が極
めて少ない優れた清浄性を有する鋼を安定して製造する
ことができる。具体的には、重量％で、Ｃ：０．５〜
１．２％、Ｓｉ：０．２〜１．５％、Ｍｎ：０．２〜
１．５％、Ｃｒ：０．５〜２．０％、Ａｌ：０．０１〜
０．０７％、Ｍｏ：０．３％以下を含有し、Ｐ：０．０
３％以下、Ｓ：０．０２％以下、Ｏ（酸素）：０．００
１５％以下、Ｖ：０．１％以下であり、残部がＦｅおよ
びその他の不可避的不純物からなる鋼であって、粒径が
２０μｍ以上のＡｌ2 Ｏ3 系介在物の量が検鏡測定を行
っても検出されない鋼を製造することが可能である。According to the method (2) of the present invention, it is possible to stably produce a steel having a low oxygen concentration and excellent cleanliness with very few large Al 2 O 3 inclusions. Can be. Specifically, in weight%, C: 0.5 to
1.2%, Si: 0.2 to 1.5%, Mn: 0.2 to
1.5%, Cr: 0.5 to 2.0%, Al: 0.01 to
0.07%, Mo: 0.3% or less, P: 0.0
3% or less, S: 0.02% or less, O (oxygen): 0.00
15% or less, V: 0.1% or less, the balance being steel consisting of Fe and other unavoidable impurities, the amount of Al 2 O 3 -based inclusions having a particle size of 20 μm or more was determined by microscopic measurement. It is possible to produce steel that is not detected when performed.
【００３２】しかも、この方法によれば、真空精錬装置
等を用いず、簡便に、また、高い生産性をもって効率よ
く製造することができる。Further, according to this method, it is possible to simply and efficiently manufacture the apparatus with high productivity without using a vacuum refining apparatus or the like.
【００３３】[0033]
【実施例】清浄鋼として軸受鋼を溶製した場合を例に挙
げて説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a bearing steel is produced as clean steel will be described.
【００３４】溶銑予備処理を行って低〔Ｐ〕および低
〔Ｓ〕濃度とした高炉溶銑を用い、転炉で脱炭精錬を行
った。この精錬時に、転炉内または出鋼直後の取鍋内
で、あるいはその両方で、Ｓｉ、Ｍｎ、Ｃｒなどの合金
鉄を添加して鋼組成を調整した。なお、出鋼量は７０
ｔ、出鋼温度は１６６０℃であった。Using a blast furnace hot metal having a low [P] and low [S] concentration by performing hot metal pretreatment, decarburization refining was performed in a converter. During this refining, a steel composition was adjusted by adding an alloyed iron such as Si, Mn, or Cr in the converter and / or in the ladle immediately after tapping. The tapping amount is 70
t, the tapping temperature was 1660 ° C.
【００３５】出鋼に当たっては、取鍋内に流入する転炉
スラグの量を極力少なくし、かつ、取鍋内に流入した僅
かの転炉スラグはスラグドラッガーを用いて完全に排除
した。その後、合成フラックス（ＣａＯ５０％−ＳｉＯ
2 ４５％−ＣａＦ2 ５％）を２５０ｋｇ添加し、溶鋼の
大気との接触による酸化を防止した。なお、取鍋には、
ハイアルミナ製の耐火物が内張りされたものを使用し
た。In tapping, the amount of converter slag flowing into the ladle was reduced as much as possible, and a small amount of converter slag flowing into the ladle was completely removed using a slag dragger. Then, the synthetic flux (CaO50% -SiO
The 2 45% -CaF 2 5%) was added 250 kg, to prevent oxidation due to contact with the atmosphere of the molten steel. In addition, in ladle,
A high-alumina refractory lined was used.
【００３６】上記の精錬で得られた粗溶鋼に、上吹きラ
ンスを用いて非脱酸剤からなるフラックスの吹き込みを
行った。フラックスとしては、ＣａＯ６０％−ＣａＦ2
４０％（重量％）の組成のものを用いた。フラックス吹
き込み時はシュノーケルを用いて溶鋼の飛散および溶鋼
攪拌時の大気との接触による再酸化を防止した。この処
理時に取鍋の底部から吹き込んだＡｒの流量は１５００
Ｎｌ（ノルマルリットル）／ｍｉｎであり、処理時間は
５分、処理による溶鋼の温度降下は３０℃であった。A flux consisting of a non-deoxidizing agent was blown into the crude molten steel obtained by the above refining using a top blowing lance. The flux was CaO 60% -CaF 2
A composition having a composition of 40% (% by weight) was used. At the time of flux injection, a snorkel was used to prevent scattering of molten steel and reoxidation due to contact with the atmosphere during molten steel stirring. The flow rate of Ar blown from the bottom of the ladle during this treatment was 1500
Nl (normal liter) / min, the treatment time was 5 minutes, and the temperature drop of the molten steel due to the treatment was 30 ° C.
【００３７】続いて、この溶鋼に合成フラックス（Ｃａ
Ｏ５０％−ＳｉＯ2 ２５％−ＣａＦ2 ２５％）を１．５
ｔ添加した後、電極加熱式精錬炉（ＶＡＤ装置）を用い
て加熱しながら取鍋の底部に設置したポーラスプラグか
らＡｒを吹き込み、溶鋼を攪拌するフラックス精錬を行
った。このフラックス精錬の所要時間は５０分であり、
この間に、溶鋼中の〔Ａｌ〕濃度が所望の濃度となるよ
うに溶鋼にショットＡｌを添加した。なお、Ａｌ添加前
の溶鋼の〔Ｏ〕濃度は１５ｐｐｍ以下であり、また、Ａ
ｌ添加前のスラグの（ＦｅＯ＋ＭｎＯ）濃度は０．３重
量％以下であった。Subsequently, a synthetic flux (Ca) was added to the molten steel.
O50% -SiO 2 25% -CaF 2 25%) 1.5
After the addition of t, flux refining was performed by blowing Ar from a porous plug installed at the bottom of the ladle while heating using an electrode heating type refining furnace (VAD apparatus) and stirring the molten steel. The time required for this flux refining is 50 minutes,
During this time, shot Al was added to the molten steel so that the [Al] concentration in the molten steel became a desired concentration. The [O] concentration of the molten steel before the addition of Al was 15 ppm or less.
The (FeO + MnO) concentration of the slag before the addition of 1 was 0.3% by weight or less.
【００３８】また、比較例として、出鋼時にＡｌを添加
し、その後、非脱酸剤フラックスの吹き込みによる予備
脱酸を行わず、ＶＡＤ装置にて上記と同様のフラックス
精錬を行い、このＶＡＤ処理中にＡｌを添加して溶鋼中
の〔Ａｌ〕濃度を所望の濃度となるように調整する方法
を実施した。なお、このときのＡｌ添加前の溶鋼の
〔Ｏ〕濃度は５０〜１００ｐｐｍであった。Further, as a comparative example, Al was added at the time of tapping, and then the same flux refining was carried out in a VAD apparatus as in the above, without performing preliminary deoxidation by blowing in a non-deoxidizing agent flux. A method of adjusting the [Al] concentration in the molten steel to a desired concentration by adding Al to the steel was carried out. At this time, the [O] concentration of the molten steel before the addition of Al was 50 to 100 ppm.
【００３９】上記のようにして得られた実施例の鋼およ
び比較例の鋼の化学組成はきわめて類似しており、いず
れの鋼も、重量％で、Ｃ：１．０％、Ｓｉ：０．２５〜
０．２７％、Ｍｎ：０．３５〜０．４０％、Ｃｒ：１．
３５〜１．４０％、Ａｌ：０．０１８〜０．０２２％、
Ｐ：０．００９〜０．０１５％、Ｓ：０．００５〜０．
００９％、Ｏ（酸素）：８ｐｐｍの組成範囲内であっ
た。The chemical compositions of the steels of the examples and the comparative examples obtained as described above are very similar, and all the steels are 1.0% by weight of C and 0.1% by weight of Si. 25-
0.27%, Mn: 0.35 to 0.40%, Cr: 1.
35-1.40%, Al: 0.018-0.022%,
P: 0.009 to 0.015%, S: 0.005 to 0.
09%, O (oxygen): within the composition range of 8 ppm.
【００４０】上記の各溶鋼を連続鋳造してブルーム鋳片
とし、１８ｍｍφまで圧延加工を行った。この半製品の
全酸素濃度は、実施例の鋼および比較例の鋼のいずれに
ついても７ｐｐｍ以下であった。また、２０μｍ以上の
大型介在物は、検鏡して調べた結果、実施例の鋼では０
個／１００ｍｍ2 で、全く認められなかったが、比較例
の鋼では０．５〜１個／１００ｍｍ2 存在していた。Each of the above molten steels was continuously cast into bloom cast pieces, which were rolled to 18 mmφ. The total oxygen concentration of this semi-finished product was 7 ppm or less for both the steel of the example and the steel of the comparative example. In addition, as a result of examining a large inclusion having a size of 20 μm or more by microscopy, the inclusion of 0%
No steel / 100 mm 2 was observed at all, but 0.5 to 1 steel / 100 mm 2 was present in the steel of the comparative example.
【００４１】次いで、これらの鋼について、スラスト型
転動疲労試験機により転動疲労寿命のテストを行った。
その結果、実施例の鋼は比較例の鋼に比べて１０倍以上
の長寿命を有することを確認した。Next, these steels were tested for rolling fatigue life using a thrust rolling fatigue tester.
As a result, it was confirmed that the steel of the example had a service life 10 times or more longer than that of the steel of the comparative example.
【００４２】[0042]
【発明の効果】本発明の清浄鋼の溶製方法によれば、溶
鋼中の〔Ｏ〕濃度が低く、しかも大型のＡｌ2 Ｏ3 系介
在物の発生が極めて少ない優れた清浄性を有する鋼を、
真空精錬装置等を用いず、簡便に、しかも低コストで効
率よく溶製することができる。According to the method for smelting clean steel of the present invention, a steel having an excellent cleanability having a low [O] concentration in the molten steel and having very few large Al 2 O 3 inclusions. To
Without using a vacuum refining device or the like, the smelting can be performed simply, at low cost, and efficiently.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本発明方法の製造フローを従来の製造フローと
対比して示す図である。FIG. 1 is a diagram showing a production flow of the method of the present invention in comparison with a conventional production flow.
【図２】取鍋スラグ中の（ＦｅＯ＋ＭｎＯ）濃度と溶鋼
中の〔Ｏ〕濃度の関係を示す図である。FIG. 2 is a diagram showing the relationship between the (FeO + MnO) concentration in a ladle slag and the [O] concentration in molten steel.
Claims (2)
面のスラグを除去した後、ＣａＯ、ＣａＦ2 、ＭｇＯお
よびＣａＣＯ3 のうちの一種以上を含む非脱酸剤フラッ
クスを吹き込んで予備脱酸を行い、次いで、フラックス
精錬を行うとともにそのフラックス精錬の間にＡｌを添
加して脱酸することを特徴とする清浄鋼の溶製方法。1. After removing slag on the surface of molten steel deoxidized by an element other than Al, a non-deoxidizing agent flux containing at least one of CaO, CaF 2 , MgO and CaCO 3 is blown into the molten steel for preliminary deoxidation. A method for producing a clean steel, comprising: performing an acid, then performing a flux refining, and adding Al during the flux refining to deoxidize.
〔Ｏ〕濃度を２０ｐｐｍ以下とし、かつ、スラグ中の
（ＦｅＯ＋ＭｎＯ）濃度を１重量％以下とする請求項１
に記載の清浄鋼の溶製方法。2. The method according to claim 1, wherein the [O] concentration in the molten steel after blowing the non-oxidizing agent flux is 20 ppm or less, and the (FeO + MnO) concentration in the slag is 1% by weight or less.
3. The method for producing clean steel according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9108843A JPH10298631A (en) | 1997-04-25 | 1997-04-25 | Method for melting clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9108843A JPH10298631A (en) | 1997-04-25 | 1997-04-25 | Method for melting clean steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10298631A true JPH10298631A (en) | 1998-11-10 |
Family
ID=14494996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9108843A Pending JPH10298631A (en) | 1997-04-25 | 1997-04-25 | Method for melting clean steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10298631A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100402005B1 (en) * | 1999-09-10 | 2003-10-17 | 주식회사 포스코 | A METHOD FOR REFINING ULTRA LOW CARBON Al-KILLED STEEL OF HIGH CLEANINESS |
| JP2009074151A (en) * | 2007-09-21 | 2009-04-09 | Sanyo Special Steel Co Ltd | Production method of steel excellent in rolling fatigue life |
| JP2010196114A (en) * | 2009-02-25 | 2010-09-09 | Jfe Steel Corp | Method for producing bearing steel |
| JP2018141221A (en) * | 2017-02-28 | 2018-09-13 | Ｊｆｅスチール株式会社 | Production method of high cleanliness steel |
| JP6981589B1 (en) * | 2020-06-16 | 2021-12-15 | Ｊｆｅスチール株式会社 | Manufacturing method of high cleanliness steel |
| WO2021256161A1 (en) * | 2020-06-16 | 2021-12-23 | Ｊｆｅスチール株式会社 | Process for producing steel having high cleanliness |
| CN114959178A (en) * | 2022-05-18 | 2022-08-30 | 广西盛隆冶金有限公司 | Deoxidizer, preparation method of steel, steel and application |
-
1997
- 1997-04-25 JP JP9108843A patent/JPH10298631A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100402005B1 (en) * | 1999-09-10 | 2003-10-17 | 주식회사 포스코 | A METHOD FOR REFINING ULTRA LOW CARBON Al-KILLED STEEL OF HIGH CLEANINESS |
| JP2009074151A (en) * | 2007-09-21 | 2009-04-09 | Sanyo Special Steel Co Ltd | Production method of steel excellent in rolling fatigue life |
| JP2010196114A (en) * | 2009-02-25 | 2010-09-09 | Jfe Steel Corp | Method for producing bearing steel |
| JP2018141221A (en) * | 2017-02-28 | 2018-09-13 | Ｊｆｅスチール株式会社 | Production method of high cleanliness steel |
| JP6981589B1 (en) * | 2020-06-16 | 2021-12-15 | Ｊｆｅスチール株式会社 | Manufacturing method of high cleanliness steel |
| WO2021256161A1 (en) * | 2020-06-16 | 2021-12-23 | Ｊｆｅスチール株式会社 | Process for producing steel having high cleanliness |
| CN115702252A (en) * | 2020-06-16 | 2023-02-14 | 杰富意钢铁株式会社 | Method for manufacturing high-cleanliness steel |
| CN115702252B (en) * | 2020-06-16 | 2024-04-02 | 杰富意钢铁株式会社 | Method for manufacturing high-cleanliness steel |
| CN114959178A (en) * | 2022-05-18 | 2022-08-30 | 广西盛隆冶金有限公司 | Deoxidizer, preparation method of steel, steel and application |
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