JPH10158720A - High purification refining method for stainless steel - Google Patents
High purification refining method for stainless steelInfo
- Publication number
- JPH10158720A JPH10158720A JP33018696A JP33018696A JPH10158720A JP H10158720 A JPH10158720 A JP H10158720A JP 33018696 A JP33018696 A JP 33018696A JP 33018696 A JP33018696 A JP 33018696A JP H10158720 A JPH10158720 A JP H10158720A
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- Prior art keywords
- inclusions
- refining
- concentration
- stainless steel
- mgo
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Abstract
(57)【要約】
【課題】 ステンレス鋼の精錬法において、硬質介在物
の発生を抑制し、かつ介在物個数を低減させて、加工時
における介在物の延性を向上させることにより、介在物
起因の表面疵や割れ等を低減させる。
【解決手段】 ステンレス鋼の精錬において、還元精錬
時に還元剤としてSiを用い、Al含有物質を無添加とし
て、鋼中のT.[Al]濃度を50ppm 以下に制御し、かつ還元
精錬後のスラグ組成をmass％で、下記条件に制御するこ
とを特徴とするステンレス鋼の高清浄化精錬法。
1.4≦T.(CaO)/(SiO2)≦2.0 、 (Al2O3)≦6 、 7≦(MgO)
≦15
(57) [Summary] [PROBLEMS] In a refining method for stainless steel, the generation of hard inclusions is suppressed, the number of inclusions is reduced, and the ductility of inclusions during processing is improved, thereby causing inclusions. Surface flaws and cracks are reduced. SOLUTION: In the refining of stainless steel, Si is used as a reducing agent during reductive refining, an Al-containing substance is not added, the concentration of T. [Al] in steel is controlled to 50 ppm or less, and slag after refining and refining. A highly purified refining method for stainless steel, characterized in that the composition is controlled to the following conditions by mass%. 1.4 ≦ T. (CaO) / (SiO 2 ) ≦ 2.0, (Al 2 O 3 ) ≦ 6, 7 ≦ (MgO)
≤15
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ステンレス鋼の精
錬法において、鋼中のTotal[Al](以下、単にT.[Al]とい
う) 濃度およびスラグ組成を制御することにより、溶鋼
中の非金属介在物（以下、単に介在物という）の無害化
をはかる高清浄度ステンレス鋼の製造方法に関するもの
である。BACKGROUND OF THE INVENTION The present invention relates to a method for refining stainless steel by controlling the total [Al] (hereinafter simply referred to as T. [Al]) concentration and the slag composition in the molten steel. The present invention relates to a method for producing high cleanliness stainless steel for detoxifying metal inclusions (hereinafter simply referred to as inclusions).
【０００２】[0002]
【従来の技術】ステンレス鋼中の介在物は、その量が多
すぎたり、融点が高く硬質の場合には、製品の介在物起
因の表面疵や加工時の割れの発生原因となる。一般に介
在物を除去したり、介在物の融点を下げ軟質化する処理
はステンレス鋼の精錬ではＡＯＤ，ＶＯＤ等のいわゆる
二次精錬炉で実施している。2. Description of the Related Art Inclusions in stainless steel, if their amount is too large or their melting points are high and hard, may cause surface flaws due to inclusions in products and cracks during processing. Generally, the process of removing inclusions or lowering the melting point of inclusions and softening them is performed in a so-called secondary refining furnace such as AOD or VOD in refining stainless steel.
【０００３】すなわち、酸素ガスを含むガスを吹込み、
脱炭等の処理を行う酸化精錬の終了後、酸化精錬時に生
成したクロム酸化物を含むスラグを還元するために、Ca
Oを主体とする塩基性フラックスと共に、SiやAl等を含
む還元剤を添加し、Arガスや窒素ガス等の不活性ガスを
吹込むことにより撹拌し、脱酸および介在物の除去を促
進させている。特殊な成分や介在物等の規制がない限り
は、一般的には還元剤としては金属SiやFe-Si等のSiを
含む金属（以下、単にSiという）がコスト的にも有利な
ことから使用されている。That is, a gas containing oxygen gas is blown,
After the end of the oxidizing refining that performs treatment such as decarburization, to reduce the slag containing chromium oxide generated during the oxidizing refining,
Add a reducing agent containing Si, Al, etc. together with a basic flux mainly composed of O, and stir by blowing an inert gas such as Ar gas or nitrogen gas to promote deoxidation and removal of inclusions. ing. As long as there are no restrictions on special components or inclusions, metals containing Si such as metal Si or Fe-Si (hereinafter simply referred to as Si) are generally cost-effective as reducing agents. It is used.
【０００４】還元剤にSiを用いて、介在物起因の製品欠
陥を防止する精錬法として、特開平３−２６７３１２号
公報、特開平４−９９２１５号公報および特開平８−１
０４９１５号公報に記載の精錬法が知られている。これ
らの方法はいずれも介在物起因の地疵が発生しやすい鏡
面仕上げ用ステンレス鋼素材の製造に適用されているも
のであり、介在物中のAl2O3濃度を皆無とし、かつ、介
在物を素材の圧延時に線状に展伸されないものとする方
法である。しかし、これらの方法では、介在物の個数お
よび量には着目しておらず、かつ介在物が圧延時に展伸
されないために製品表面に点状欠陥として残存しやす
い。そのために、鏡面仕上げ用ステンレス鋼以外では十
分な効果が得られていない。[0004] As a refining method for preventing product defects caused by inclusions by using Si as a reducing agent, JP-A-3-2673112, JP-A-4-99215 and JP-A-8-1.
A refining method described in Japanese Patent No. 04915 is known. All of these methods are applied to the manufacture of stainless steel material for mirror finishing, in which ground flaws due to inclusions are liable to occur, and the Al 2 O 3 concentration in the inclusions is completely eliminated. Is not stretched linearly during rolling of the material. However, in these methods, attention is not paid to the number and amount of inclusions, and the inclusions do not expand during rolling, so that they tend to remain as point defects on the product surface. Therefore, a sufficient effect has not been obtained except for stainless steel for mirror finishing.
【０００５】一方、還元剤としてSiを用い、硬質の介在
物であるMgO-Al2O3スピネル系介在物の生成を防止する
方法として、特開平６−３０６４３８号公報の精錬法が
知られている。この方法は精錬炉の内張り耐火物にマグ
ネシア・クロマイト系を用い、かつ精錬後のスラグ組成
を(MgO)濃度で７mass％以下、(Al2O3)濃度で５mass％以
下、スラグ塩基度T.(CaO)/(SiO2)を1.3から1.9の範囲に
コントロールする方法である。しかし、この方法ではマ
グネシア・クロマイト系の内張り耐火物を用いた中で(M
gO)濃度を７mass％以下にすることは非常に難しいため
に、安定して制御することが出来ない。On the other hand, a refining method disclosed in JP-A-6-306438 is known as a method of using Si as a reducing agent to prevent the formation of hard inclusions of MgO-Al 2 O 3 spinel inclusions. I have. This method uses a magnesia-chromite system for the refractory lining of the refining furnace, and the slag composition after refining is 7 mass% or less in (MgO) concentration, 5 mass% or less in (Al 2 O 3 ) concentration, and slag basicity T. This is a method of controlling (CaO) / (SiO 2 ) in the range of 1.3 to 1.9. However, this method uses magnesia-chromite lining refractories (M
Since it is very difficult to reduce the gO) concentration to 7 mass% or less, stable control cannot be performed.
【０００６】[0006]
【発明が解決しようとする課題】本発明はステンレス鋼
の精錬法において、還元剤にSiを用い、鋼中のT.[Al]濃
度を制御し、かつ還元後のスラグ組成を制御することに
より、硬質のAl2O3 およびMgO-Al2O3系介在物の生成を
安定して防止して、製品の表面疵や加工時の割れを防止
することを目的とするものである。SUMMARY OF THE INVENTION The present invention relates to a method for refining stainless steel by using Si as a reducing agent, controlling the T. [Al] concentration in the steel, and controlling the slag composition after reduction. Another object of the present invention is to stably prevent the formation of hard Al 2 O 3 and MgO—Al 2 O 3 -based inclusions, and to prevent surface defects of products and cracks during processing.
【０００７】[0007]
【課題を解決するための手段】本発明は上記目的を達成
するために、下記手段を採用するものである。すなわ
ち、ステンレス鋼の精錬において、酸化精錬時に生成し
たクロム酸化物を含むスラグの還元剤としてSiを用い、
Al含有物質を無添加として、鋼中のT.[Al]濃度を50ppm
以下に制御し、かつ還元精錬後のスラグ組成をmass％
で、下記条件に制御することを特徴とするステンレス鋼
の高清浄化精錬法にある。 1.4≦T.(CaO)/(SiO2)≦2.0 (Al2O3)≦6 7≦(MgO)≦15The present invention adopts the following means to achieve the above object. That is, in the refining of stainless steel, using Si as a reducing agent for slag containing chromium oxide generated during oxidative refining,
T. [Al] concentration in steel is 50ppm with no addition of Al-containing material
The slag composition after reduction and refining is controlled to mass%
And a method for highly purifying and refining stainless steel, characterized by controlling to the following conditions. 1.4 ≦ T. (CaO) / (SiO 2 ) ≦ 2.0 (Al 2 O 3 ) ≦ 67 ≦ (MgO) ≦ 15
【０００８】[0008]
【発明の実施の形態】本発明者らは、還元精錬時の還元
剤にSiを用いる場合には、製品の表面疵や加工時の割れ
に対して硬質の介在物であるAl2O3系介在物およびMgO-A
l2O3系介在物の影響が極めて大きいことを見い出した。
さらにステンレス鋼の精錬工程および鋳造工程における
介在物の生成要因について種々の調査、解析を重ねた結
果、下記知見を得た。BEST MODE FOR CARRYING OUT THE INVENTION The present inventors, when using Si as a reducing agent at the time of refining and refining, use Al 2 O 3 based hard inclusions against surface flaws of products and cracks during processing. Inclusions and MgO-A
It has been found that the influence of l 2 O 3 inclusions is extremely large.
Furthermore, as a result of repeated investigations and analyzes on the formation factors of inclusions in the refining process and the casting process of stainless steel, the following findings were obtained.
【０００９】還元精錬時に還元剤にSiを用いた場合で
も、Al含有物質の添加があった場合および鋼中T.[Al]濃
度が一定値を超えた場合には、硬質のAl2O3系介在物お
よびMgO-Al2O3系介在物が生成することがある。[0009] Even when Si is used as a reducing agent at the time of refining and refining, when Al-containing substances are added and when the T. [Al] concentration in steel exceeds a certain value, hard Al 2 O 3 System inclusions and MgO-Al 2 O 3 system inclusions may be formed.
【００１０】一般的に、還元精錬時の還元剤にSiを用
いた場合、介在物は還元精錬時および取鍋への出鋼時
に、溶鋼中へ懸濁したスラグを核に成長する。In general, when Si is used as a reducing agent at the time of refining and refining, the inclusions grow on the slag suspended in the molten steel as nuclei at the time of reducing and refining and at the time of tapping into a ladle.
【００１１】出鋼から鋳造工程において、溶鋼中の懸
濁したスラグは、溶鋼温度の低下にともない進行する脱
酸反応で生成するSiO2やAl2O3と結合して、組成変化を
起こし、Al2O3、SiO2濃度が上昇する。特にAl2O3濃度の
上昇量は溶鋼中T.[Al]濃度およびスラグ塩基度T.(CaO)/
(SiO2)（以下、T.(CaO)/(SiO2)という）に依存する。In the process from tapping to casting, the suspended slag in the molten steel combines with SiO 2 and Al 2 O 3 generated by a deoxidation reaction that proceeds with a decrease in the temperature of the molten steel, causing a change in composition. Al 2 O 3 and SiO 2 concentrations increase. In particular, the increase in the Al 2 O 3 concentration depends on the T. [Al] concentration in the molten steel and the slag basicity T. (CaO) /
(SiO 2 ) (hereinafter referred to as T. (CaO) / (SiO 2 )).
【００１２】MgO-Al2O3は介在物中のMgO、Al2O3濃度
が高い場合に球状のスラグ質の介在物(CaO-SiO2主体)の
中の一部分に析出した状態で生成する。[0012] MgO-Al 2 O 3 is formed in a state where MgO and Al 2 O 3 in the inclusions are precipitated in a part of spherical slag-like inclusions (mainly CaO-SiO 2 ) when the concentration of Al 2 O 3 is high. .
【００１３】鋼中介在物の個数および量は基本的には
鋼中のT.[O]濃度に依存するが、T.[O]濃度はスラグ塩基
度に依存するために、T.(CaO)/(SiO2)により介在物量を
コントロールすることができる。The number and amount of inclusions in the steel basically depend on the T. [O] concentration in the steel, but the T. [O] concentration depends on the slag basicity. The amount of inclusions can be controlled by) / (SiO 2 ).
【００１４】以上より、Al2O3系およびMgO-Al2O3系介在
物の生成を抑制し、介在物量を減少させるためには、還
元精錬時のAl含有物質の添加を回避して、溶鋼中T.[Al]
濃度を一定値以下とし、かつ還元精錬後のスラグ組成を
制御することが重要であることがわかった。上記の結果
に基づき、還元精錬時のAl含有物質を無添加とした条件
下で、Al2O3系およびMgO-Al2O3系介在物の生成を防止
し、かつ介在物量を減少させる条件について検討した。As described above, in order to suppress the formation of Al 2 O 3 -based and MgO-Al 2 O 3 -based inclusions and to reduce the amount of inclusions, it is necessary to avoid the addition of an Al-containing substance during reductive refining. T. [Al] in molten steel
It was found that it was important to keep the concentration below a certain value and to control the slag composition after reduction refining. Based on the above results, under conditions where the Al-containing substance was not added during the refining and refining, conditions for preventing the formation of Al 2 O 3 -based and MgO-Al 2 O 3 -based inclusions and reducing the amount of inclusions Was considered.
【００１５】図１には、Siによる還元精錬後の溶鋼中T.
[Al]濃度と硬質介在物の発生率の関係を示す。なお、硬
質介在物の発生率とは鋳片内に存在する５μｍ以上の介
在物の10個以上について組成分析を行い、その中でAl2O
3系およびMgO-Al2O3 系介在物の単体あるいはスラグ系
介在物の中にこれらの介在物の晶出相が認められた介在
物の比率である。FIG. 1 shows that T. in molten steel after reduction smelting with Si.
The relationship between the [Al] concentration and the incidence of hard inclusions is shown. Note that the incidence of hard inclusions perform composition analysis 10 or more 5μm or more inclusions present in the cast slab, Al 2 O therein
This is the ratio of inclusions in which the crystallization phase of these inclusions was recognized in the ternary or MgO-Al 2 O 3 -based inclusions alone or in the slag-based inclusions.
【００１６】図１より、T.[Al]濃度が50ppmを超えると
硬質介在物の発生率が急激に増大する。したがって、硬
質介在物の発生率を低位に抑えるためには、鋼中T.[Al]
濃度を50ppm以下にする必要がある。As shown in FIG. 1, when the T. [Al] concentration exceeds 50 ppm, the incidence of hard inclusions sharply increases. Therefore, in order to reduce the incidence of hard inclusions to a low level, T. [Al]
The concentration must be less than 50 ppm.
【００１７】図２には、還元精錬後の最終のT.(CaO)/(S
iO2)と鋳片内の５μｍ以上の介在物の発生指数の関係を
示す。なお、T.(CaO)濃度はスラグ内に存在する(Ca)の
存在形態をすべて(CaO)として算出した濃度であり、５
μｍ以上の介在物の発生指数はT.(CaO)/(SiO2)が1.4の
時の平均の介在物個数を1.0として比例換算した値であ
る。また、この時のスラグ中(Al2O3)濃度は６mass％以
下、(MgO) 濃度は７〜15mass％の範囲にあった。図２よ
り、T.(CaO)/(SiO2)の増大と共に、５μｍ以上の介在物
の発生指数は低下する傾向にあり、介在物個数（量）を
低位に安定させるためには、T.(CaO)/(SiO2)は1.4以上
とする必要がある。FIG. 2 shows the final T. (CaO) / (S
The relationship between iO 2 ) and the index of occurrence of inclusions of 5 μm or more in the slab is shown. Note that the T. (CaO) concentration is a concentration calculated as all (CaO) existing forms of (Ca) present in the slag,
The occurrence index of inclusions of μm or more is a value obtained by proportionally converting the average number of inclusions when T. (CaO) / (SiO 2 ) is 1.4 to 1.0. At this time, the (Al 2 O 3 ) concentration in the slag was 6 mass% or less, and the (MgO) concentration was in the range of 7 to 15 mass%. From FIG. 2, the index of occurrence of inclusions of 5 μm or more tends to decrease as T. (CaO) / (SiO 2 ) increases. In order to stabilize the number (amount) of inclusions at a low level, T. (CaO) / (SiO 2 ) needs to be 1.4 or more.
【００１８】図３には、Siによる還元精錬後のスラグ組
成が(Al2O3)濃度で６mass％以下、(MgO)濃度で７〜15ma
ss％の範囲にあった場合のT.(CaO)/(SiO2)とAl2O3系お
よびMgO-Al2O3系介在物の硬質介在物の発生率の関係を
示す。なお、鋼中の T.[Al]濃度は50ppm以下であり、
硬質介在物の発生率は図１の場合と同様にし て求めた
ものである。図３より、T.(CaO)/(SiO2)が2.0を超える
と硬質介在物 が急激に増大する。したがって、硬質介
在物の発生率を低位に抑えるためには 、T.(CaO)/(SiO
2)は2.0以下とする必要がある。なお、T.(CaO)/(SiO2)
が2.0 を超えたところで認められた硬質介在物はMgO-
Al2O3系介在物が殆どであった 。FIG. 3 shows that the slag composition after reduction smelting by Si is 6 mass% or less in (Al 2 O 3 ) concentration and 7 to 15 ma in (MgO) concentration.
shows the T. (CaO) / incidence of hard inclusions (SiO 2) and Al 2 O 3 system and MgO-Al 2 O 3 inclusions relationship when in the range of ss%. The concentration of T. [Al] in steel is 50ppm or less,
The incidence of hard inclusions was determined in the same manner as in FIG. According to FIG. 3, when T. (CaO) / (SiO 2 ) exceeds 2.0, hard inclusions increase rapidly. Therefore, in order to keep the incidence of hard inclusions low, T. (CaO) / (SiO
2 ) needs to be 2.0 or less. In addition, T. (CaO) / (SiO 2 )
Is greater than 2.0, the hard inclusions found to be MgO-
Al 2 O 3 based inclusions was almost.
【００１９】図４には、Siによる還元精錬後のスラグ中
の(Al2O3)濃度と(MgO)濃度の関係における鋳片内介在物
の形態を示す。図中の○印はAl2O3系およびMgO-Al2O 3
系の硬質介在物の発生率が５％未満のもの、×印は硬質
介在物の発生率が５ ％以上のものを示す。なお、この
時の鋼中T.[Al]濃度は50ppm以下, スラグ中 T.(CaO)/
(SiO2)は1.4以上、2.0以下であった。また、(MgO)濃度
が９mass％以下のデータは精錬中にMgOの添加のないも
の、(MgO)濃度が９mass％を超えるデータは耐火物の溶
損を抑えるためにMgOの添加を行ったものである。図４
より、○印の範囲、つまり硬質介在物の発生率が５％未
満の範囲は(Al2O3)濃度６mass％以下、かつ(MgO)濃度15
mass％以下の範囲にある。また、(MgO)濃度７mass％未
満のデータは２点しかなく、非常に少ない。これはMgO
の添加無しでも耐火物等の溶損により(MgO)濃度が上昇
するためであり、(MgO)濃度７mass％未満を達成するこ
とは難しく、かつ、MgOの添加無しの場合では耐火物溶
損量が増大するためにコスト的にも不利である。FIG. 4 shows the form of inclusions in the slab in the relationship between the (Al 2 O 3 ) concentration and the (MgO) concentration in the slag after reduction smelting with Si. The circles in the figure indicate Al 2 O 3 and MgO-Al 2 O 3
When the rate of occurrence of hard inclusions is less than 5%, the mark x indicates that the rate of occurrence of hard inclusions is 5% or more. At this time, the T. [Al] concentration in the steel was 50 ppm or less, and the T. (CaO) /
(SiO 2 ) was 1.4 or more and 2.0 or less. The data with a (MgO) concentration of 9 mass% or less are those without addition of MgO during refining, and the data with a (MgO) concentration exceeding 9 mass% are those with addition of MgO to suppress erosion of refractories. It is. FIG.
Thus, in the range of the mark, that is, the range in which the occurrence rate of hard inclusions is less than 5%, the (Al 2 O 3 ) concentration is 6 mass% or less and the (MgO) concentration is 15%.
mass% or less. Also, there are only two points of data with an (MgO) concentration of less than 7 mass%, which is very small. This is MgO
This is because the (MgO) concentration increases due to the erosion of the refractory even without the addition of Mg, and it is difficult to achieve the (MgO) concentration of less than 7% by mass. Is disadvantageous in terms of cost because of the increase in
【００２０】以上より、硬質介在物の発生を抑え、かつ
介在物量を低減するためには、還元精錬時の還元剤とし
てSiを用い、Al含有物質を無添加として、鋼中のT.[Al]
濃度を50ppm以下に制御し、かつ還元精錬後のスラグ組
成を、T.(CaO)/(SiO2)で1.4以上、2.0以下、(Al2O3)濃
度６mass％以下、(MgO)濃度を７mass％以上、15mass％
以下とする必要がある。As described above, in order to suppress the generation of hard inclusions and to reduce the amount of inclusions, T. [Al in steel is used by using Si as a reducing agent during reductive refining and adding no Al-containing substance. ]
The concentration is controlled to 50 ppm or less, and the slag composition after the refining and refining is T. (CaO) / (SiO 2 ) 1.4 or more, 2.0 or less, (Al 2 O 3 ) concentration 6 mass% or less, (MgO) concentration 7 mass% or more, 15 mass%
It is necessary to:
【００２１】[0021]
【実施例】SUS304ステンレス鋼（18mass%Cr-8mass%Ni)
をスクラップ、フェロクロム、フェロニッケルを原料と
して、60t電気炉にて溶解し、ＡＯＤ炉にてO2-Ar混合ガ
スによる脱炭精錬を行った。脱炭精錬後、酸化したクロ
ムを還元回収するために、Si(Fe-Si)を添加し、合わせ
てCaO,CaF2を添加して、Arガスを吹込みながら還元精錬
を行い、取鍋に出鋼した。取鍋ではArガス吹込みによる
撹拌を行いながら、最終の成分・温度の微調整を行い、
その後、連続鋳造により断面サイズ178mmφのビレット
に鋳造した。得られたビレットは線材圧延により、 5.
5mmφの線材とし、この線材を0.5mmφに冷間伸線加工し
た。表１にAl含有物質の添加有無、鋼中のT.[Al]濃度、
還元後のスラグ組成および線材品質をまとめて示す。な
お、No. １〜６の例は本発明の例、No. ７〜12は本発明
の条件外の比較例を示す。[Example] SUS304 stainless steel (18mass% Cr-8mass% Ni)
Was melted in a 60 t electric furnace using scrap, ferrochrome and ferronickel as raw materials, and decarburized and refined with an O 2 -Ar mixed gas in an AOD furnace. After decarburization refining, to reduce recover chromium oxidized, was added Si (Fe-Si), combined CaO, with the addition of CaF 2, performs reduction refining while looking blown Ar gas, in the ladle Steel tapping. In the ladle, finely adjust the final components and temperature while stirring by blowing Ar gas.
Thereafter, it was cast into a billet having a cross section of 178 mmφ by continuous casting. The obtained billet is rolled by wire rod.5.
A wire having a diameter of 5 mm was used, and the wire was cold drawn to 0.5 mm. Table 1 shows whether or not Al-containing substances were added, the concentration of T. [Al] in steel,
The slag composition and wire quality after reduction are summarized below. Examples of Nos. 1 to 6 are examples of the present invention, and Nos. 7 to 12 are comparative examples outside the conditions of the present invention.
【００２２】介在物の調査は、線材の圧延方向の横断面
10cm2を光学顕微鏡により観察し、５μｍ以上の介在物
個数を測定すると共に、20個以上の介在物について、Ｘ
線マイクロアナライザーによる組成分析を行い、Al2O3
系、MgO-Al2O3系の硬質介在物の発生率を求めた。Inspection of inclusions was carried out in the cross section of the wire rod in the rolling direction.
10 cm 2 was observed with an optical microscope, the number of inclusions of 5 μm or more was measured, and for 20 or more inclusions, X
Perform composition analysis by line microanalyzer, Al 2 O 3
And the incidence of MgO-Al 2 O 3 -based hard inclusions were determined.
【００２３】[0023]
【表１】 [Table 1]
【００２４】本発明の例では硬質介在物の発生率が低位
に安定しており、かつ線材中の５μｍ以上の介在物個数
も低減しているために、伸線加工時の介在物起因の割れ
をなくすことができた。In the example of the present invention, the rate of occurrence of hard inclusions is stable at a low level, and the number of inclusions having a size of 5 μm or more in the wire is reduced. Was eliminated.
【００２５】[0025]
【発明の効果】本発明では、ステンレス鋼の精錬におい
て、Al含有物質の回避、鋼中のT.[Al]濃度および還元精
錬後の最終のスラグ組成を制御することによって、硬質
介在物の発生率および介在物個数（量）を低位に安定さ
せることができるので、介在物の高清浄化を達成でき
る。これにより、製品の表面疵や加工時の割れのない材
料を製造することができ、冷間加工性の優れた細線、極
細線などの製造が可能になった。According to the present invention, in the refining of stainless steel, the generation of hard inclusions is controlled by avoiding Al-containing substances, controlling the T. [Al] concentration in the steel, and controlling the final slag composition after reduction refining. Since the ratio and the number (amount) of the inclusions can be stabilized at a low level, high purification of the inclusions can be achieved. As a result, it is possible to manufacture a material free from surface flaws of the product and cracks during processing, and it has become possible to manufacture fine wires, ultrafine wires, and the like excellent in cold workability.
【図１】溶鋼中T.[Al]濃度と硬質介在物の発生率の関係
を示す図である。FIG. 1 is a graph showing the relationship between the concentration of T. [Al] in molten steel and the incidence of hard inclusions.
【図２】還元精錬後のスラグの塩基度T.(CaO)/(SiO2)と
鋳片内の５μｍ以上介在物の発生指数の関係を示す図で
ある。FIG. 2 is a graph showing the relationship between the basicity T. (CaO) / (SiO 2 ) of slag after reduction refining and the index of occurrence of inclusions of 5 μm or more in a slab.
【図３】還元精錬後のスラグ塩基度T.(CaO)/(SiO2)と硬
質介在物の発生率の関係を示す図である。FIG. 3 is a graph showing the relationship between the slag basicity T. (CaO) / (SiO 2 ) after reduction refining and the incidence of hard inclusions.
【図４】還元精錬後のスラグ中(Al2O3)濃度と(MgO)濃度
の関係における鋳片内介在物の発生形態の関係を示す図
である。FIG. 4 is a diagram showing the relationship between the (Al 2 O 3 ) concentration and the (MgO) concentration in the slag after reduction refining and the form of inclusions in the slag.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 吉村 裕二 山口県光市大字島田3434番地 新日本製鐵 株式会社光製鐵所内 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Yuji Yoshimura 3434 Shimada, Hikari-shi, Yamaguchi Prefecture Nippon Steel Corporation Hikari Works
Claims (1)
時に生成したクロム酸化物を含むスラグの還元剤として
Si含有物質を用い、Al含有物質を無添加として、鋼中の
Total[Al]濃度を50ppm以下に制御し、かつ還元精錬後の
スラグ組成をmass％で、下記条件に制御することを特徴
とするステンレス鋼の高清浄化精錬法。 1.4≦T.(CaO)/(SiO2)≦2.0 (Al2O3)≦6 7≦(MgO)≦151. In a refining of stainless steel, as a reducing agent for slag containing chromium oxide generated during oxidative refining.
Using a Si-containing material, without adding an Al-containing material,
A highly purified refining method for stainless steel, characterized in that the total [Al] concentration is controlled to 50 ppm or less, and the slag composition after reduction refining is controlled to the following conditions by mass%. 1.4 ≦ T. (CaO) / (SiO 2 ) ≦ 2.0 (Al 2 O 3 ) ≦ 67 ≦ (MgO) ≦ 15
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33018696A JPH10158720A (en) | 1996-11-27 | 1996-11-27 | High purification refining method for stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33018696A JPH10158720A (en) | 1996-11-27 | 1996-11-27 | High purification refining method for stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10158720A true JPH10158720A (en) | 1998-06-16 |
Family
ID=18229801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33018696A Pending JPH10158720A (en) | 1996-11-27 | 1996-11-27 | High purification refining method for stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10158720A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100429158B1 (en) * | 1999-10-20 | 2004-04-28 | 주식회사 포스코 | Method for decarburizing austenite stainless steel |
| KR100729123B1 (en) | 2005-12-01 | 2007-06-14 | 주식회사 포스코 | Manufacturing method of low carbon austenitic stainless steel |
| KR100889685B1 (en) * | 2002-12-24 | 2009-03-19 | 주식회사 포스코 | Highly clean refining method of stainless steel |
| JP2009114491A (en) * | 2007-11-05 | 2009-05-28 | Jfe Steel Corp | Method for refining molten steel by rh-vacuum degassing apparatus |
| KR100941841B1 (en) | 2007-12-18 | 2010-02-11 | 주식회사 포스코 | Manufacturing method of austenitic stainless steel |
| KR101441302B1 (en) * | 2012-12-24 | 2014-11-03 | 주식회사 포스코 | Stainless steel and method of manufacturing the same |
-
1996
- 1996-11-27 JP JP33018696A patent/JPH10158720A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100429158B1 (en) * | 1999-10-20 | 2004-04-28 | 주식회사 포스코 | Method for decarburizing austenite stainless steel |
| KR100889685B1 (en) * | 2002-12-24 | 2009-03-19 | 주식회사 포스코 | Highly clean refining method of stainless steel |
| KR100729123B1 (en) | 2005-12-01 | 2007-06-14 | 주식회사 포스코 | Manufacturing method of low carbon austenitic stainless steel |
| JP2009114491A (en) * | 2007-11-05 | 2009-05-28 | Jfe Steel Corp | Method for refining molten steel by rh-vacuum degassing apparatus |
| KR100941841B1 (en) | 2007-12-18 | 2010-02-11 | 주식회사 포스코 | Manufacturing method of austenitic stainless steel |
| KR101441302B1 (en) * | 2012-12-24 | 2014-11-03 | 주식회사 포스코 | Stainless steel and method of manufacturing the same |
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