JPH0730388B2 - Low oxygen ultra low carbon steel manufacturing method - Google Patents
Low oxygen ultra low carbon steel manufacturing methodInfo
- Publication number
- JPH0730388B2 JPH0730388B2 JP1191525A JP19152589A JPH0730388B2 JP H0730388 B2 JPH0730388 B2 JP H0730388B2 JP 1191525 A JP1191525 A JP 1191525A JP 19152589 A JP19152589 A JP 19152589A JP H0730388 B2 JPH0730388 B2 JP H0730388B2
- Authority
- JP
- Japan
- Prior art keywords
- slag
- molten steel
- ladle
- carbon steel
- low carbon
- 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.)
- Expired - Fee Related
Links
- 229910001209 Low-carbon steel Inorganic materials 0.000 title claims description 10
- 239000001301 oxygen Substances 0.000 title claims description 7
- 229910052760 oxygen Inorganic materials 0.000 title claims description 7
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title description 4
- 239000002893 slag Substances 0.000 claims description 32
- 229910000831 Steel Inorganic materials 0.000 claims description 28
- 239000010959 steel Substances 0.000 claims description 28
- 238000005261 decarburization Methods 0.000 claims description 18
- 230000001590 oxidative effect Effects 0.000 claims description 10
- 238000009849 vacuum degassing Methods 0.000 claims description 10
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 8
- 239000003638 chemical reducing agent Substances 0.000 claims description 6
- 238000007670 refining Methods 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 238000009628 steelmaking Methods 0.000 claims description 2
- 238000010079 rubber tapping Methods 0.000 description 11
- 230000007547 defect Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000003607 modifier Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052903 pyrophyllite Inorganic materials 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
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)
Description
【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、極低炭素鋼の高清浄化の方法に関するもので
ある。TECHNICAL FIELD The present invention relates to a method for highly cleaning ultra-low carbon steel.
〈従来の技術〉 近年、自動車用薄鋼板の材質特性の品質要求が厳しくな
り、より低い炭素および窒素含有量の鋼が必要となって
きている。また、この薄鋼板では表面品質の要求も厳し
く高清浄化が必要となっている。このような低酸素極低
炭素鋼の溶製は、従来転炉で［Ｃ］を0.02〜0.05重量％
（以下％と略す）程度まで吹き下げたのち、未脱酸で出
鋼されRH式真空脱ガス装置において、［Ｃ］を0.002％
以下まで真空脱炭され続いて脱酸、成分の微調整が行わ
れる。<Prior Art> In recent years, quality requirements for material characteristics of thin steel sheets for automobiles have become strict, and steels having lower carbon and nitrogen contents have been required. In addition, the demand for surface quality of this thin steel sheet is severe, and high cleanliness is required. Such low-oxygen ultra-low carbon steel is melted in a conventional converter with 0.02 to 0.05% by weight of [C].
After being blown down to about (abbreviated as "%" below), the steel was undeoxidized and tapped in a RH-type vacuum degassing device, where [C] was 0.002%.
Vacuum decarburization is performed until the following, followed by deoxidation and fine adjustment of components.
極低炭素鋼を製造する際には、転炉で［Ｃ］を吹き下げ
るため出鋼時にFeO,MnO濃度の高い酸化性スラグが溶鋼
上に生成し、FeO,MnOは２次精錬後においてもそのまま
高濃度でスラグ中に残存してしまう。これらのFeO,MnO
は２次精錬後に鋼中の［Al］，［Ti］等のより酸化され
やすい元素と反応して微小な介在物を生成させる。この
介在物は、連続鋳造のノズル詰まりや製品表面の欠陥の
原因となる。When manufacturing ultra-low carbon steel, since [C] is blown down in the converter, oxidizing slag with high FeO and MnO concentration is produced on molten steel at the time of tapping, and FeO and MnO remain even after secondary refining. It remains in the slag with high concentration as it is. These FeO, MnO
After secondary refining, it reacts with more easily oxidizable elements such as [Al] and [Ti] in the steel to form minute inclusions. This inclusion causes nozzle clogging in continuous casting and defects on the product surface.
［Ｃ］が0.02％以上の場合には、出鋼時に脱酸剤と同時
にフラックス及びスラグ改質剤を添加し、転炉だけで満
足すべき清浄度が得られている（例えば、特開昭62-392
05号公報）が、［Ｃ］が0.002％以下の極低炭素鋼の場
合には、真空脱炭処理が不可欠であり、出鋼中にスラグ
の還元剤を投入しても、溶鋼が脱酸されていないために
十分な還元が行われない。一方、あまりスラグ脱酸を進
めると溶鋼が脱酸されて、脱炭処理に必要な酸素が不足
することになる。When [C] is 0.02% or more, the flux and slag modifier are added at the same time as the deoxidizing agent at the time of tapping, and a satisfactory cleanliness is obtained only by the converter (for example, Japanese Patent Laid-Open No. Sho 60-86). 62-392
No. 05 gazette), in the case of ultra-low carbon steel with a [C] of 0.002% or less, vacuum decarburization treatment is indispensable, and molten steel is deoxidized even if a reducing agent for slag is added during tapping. Because it is not done, sufficient reduction is not performed. On the other hand, if the slag deoxidation is promoted too much, the molten steel will be deoxidized and the oxygen required for decarburization will be insufficient.
〈発明が解決しようとする課題〉 本発明は、上記の問題を解決し、特に極低炭素領域の溶
鋼の高清浄化を図ることを目的としたものである。<Problems to be Solved by the Invention> The present invention is intended to solve the above-mentioned problems, and particularly to achieve high cleaning of molten steel in an extremely low carbon region.
〈課題を解決するための手段〉 本発明は、製鋼炉から取鍋へ出鋼した溶鋼を真空脱ガス
装置で脱炭処理に続いて脱酸処理を行い、炭素0.002％
以下の極低炭素鋼を製造する２次精錬において、SiO2濃
度30％未満の高アルミナ質耐火物内張りの取鍋を使用
し、脱炭処理までは酸化性スラグを取鍋の溶鋼上に保持
し脱炭処理に続く脱酸処理の開始と同時にスラグ還元剤
を添加し、前記酸化性スラグを攪拌し、還元することに
よって介在物を低減することを特徴とする低酸素極低炭
素鋼製造方法である。<Means for Solving the Problems> The present invention is to perform deoxidation treatment following decarburization treatment with molten steel produced from a steelmaking furnace to a ladle in a vacuum degassing device, and to remove carbon 0.002%.
In the secondary refining to produce the following ultra-low carbon steels, a ladle with a high alumina refractory lining with a SiO 2 concentration of less than 30% is used, and the oxidizing slag is kept on the molten steel of the ladle until decarburization. A deoxidizing treatment following the decarburizing treatment, a slag reducing agent is added simultaneously with the start of the deoxidizing treatment, and the inclusions are reduced by stirring and reducing the oxidizing slag. Is.
〈作用〉 取鍋内溶鋼を真空脱ガス装置で脱炭処理し脱酸処理を行
う２次精錬の際、従来は出鋼前に脱酸剤で脱酸した溶鋼
を、真空脱ガス装置で脱炭脱酸していたが、本発明で
は、出鋼時に未脱酸のまヽとし、又は脱炭に必要な酸素
濃度に調整し、真空脱ガス装置で脱炭処理するまでは酸
化性スラグを取鍋の溶鋼上に保持し、脱炭処理をした。<Operation> During secondary refining, in which the molten steel in the ladle is decarburized and deoxidized with a vacuum degassing device, the molten steel deoxidized with a deoxidizing agent before tapping was degassed with a vacuum degassing device. Although it was deoxidized by charcoal, in the present invention, it is not deoxidized at the time of tapping, or the oxygen concentration necessary for decarburization is adjusted, and oxidizing slag is removed until decarburization treatment is performed by a vacuum degassing device. It was held on the molten steel in the ladle and decarburized.
従来例の場合、出鋼時のスラグ中Ｔ・Feは著しく低下し
ている一方、真空脱炭処理に時間がかヽっていた。本発
明では出鋼時、酸化性スラグが残っているので真空脱炭
処理は余分な時間をとらずにできる。In the case of the conventional example, T / Fe in the slag at the time of tapping was remarkably reduced, but the vacuum decarburization treatment took a long time. In the present invention, since the oxidizing slag remains at the time of tapping, vacuum decarburization treatment can be performed without taking extra time.
また、脱炭処理に続く脱酸剤による脱酸処理の開始と同
時にスラグ還元剤を添加し、攪拌し酸化性スラグを還元
することによって、スラグ中のFeO,MnO等の溶鋼汚染源
を還元し、溶鋼のより清浄化を達成できる。Further, by adding a slag reducing agent at the same time as the start of the deoxidizing treatment with a deoxidizing agent following the decarburizing treatment, and stirring and reducing the oxidizing slag, FeO in the slag, a source of molten steel such as MnO is reduced, More clean of molten steel can be achieved.
上記スラグ還元剤はスラグとの反応を良くするため、取
鍋上に広く散布するとともに、機械あるいはガスによっ
てスラグ層を攪拌することが必要である。更に、取鍋耐
火物中のSiO2濃度が高い場合例えば、耐火材としてジル
コン（ZrO2SiO2…SiO2濃度50％以上）やろう石（SiO2濃
度80％以上）を用いる時には、鋼中の［Al］，［Ti］等
のより酸化されやすい元素と反応して微小な介在物を生
成させる。従って、低酸素極低炭素鋼製造用耐火物は低
SiO2のもの例えば、高アルミナ質耐火物（SiO2濃度30％
未満）を選ぶ必要がある。In order to improve the reaction of the slag reducing agent with the slag, it is necessary to sprinkle the slag layer widely on the ladle and stir the slag layer by a machine or gas. Furthermore, when the SiO 2 concentration in the ladle refractory is high, for example, when using zircon (ZrO 2 SiO 2 ... SiO 2 concentration 50% or more) or pyrophyllite (SiO 2 concentration 80% or more) as the refractory material, Reacts with the more easily oxidizable elements such as [Al] and [Ti] to produce fine inclusions. Therefore, refractory materials for low oxygen ultra low carbon steel production are low
SiO 2 For example, high alumina refractory (SiO 2 concentration 30%
Less than) must be selected.
〈実施例〉 従来例、比較例および実施例を以下に説明する。<Examples> Conventional examples, comparative examples and examples will be described below.
従来例； 出鋼時の溶鋼成分C:0.03％、FreeO:650ppm、スラグ中T.
Fe:12％で脱酸せずに出鋼した。RH式真空脱ガス装置に
て、脱炭処理し、C:20ppmにした後、Al脱酸を行ない合
金を添加した。RH式真空脱ガス処理終了時のT.O＝40ppm
であった。この溶鋼を周知の方法で連続鋳造、熱間圧
延、冷間圧延等の工程を経て製品とした。この場合、T.
Oと介在物起因の表面欠陥との関係は第１図のようにな
る。連続鋳造の定常鋳込み相当部分の介在物による表面
欠陥は、目視観察で３％存在した。Conventional example: Molten steel composition at the time of tapping: 0.03%, FreeO: 650ppm, T. in slag.
Fe: 12% was tapped without deoxidation. After decarburization treatment with an RH type vacuum degasser to make C: 20 ppm, Al was deoxidized and an alloy was added. TO = 40ppm at the end of RH type vacuum degassing
Met. This molten steel was made into a product through steps such as continuous casting, hot rolling and cold rolling according to known methods. In this case, T.
The relationship between O and surface defects caused by inclusions is as shown in FIG. Surface defects due to inclusions in a portion corresponding to steady casting in continuous casting were 3% by visual observation.
比較例； 出鋼時の溶鋼成分C:0.03％、FreeO:730ppm、スラグ中T.
Fe:14％で脱酸せずに出鋼した。出鋼後の取鍋上のスラ
グ中のFeO,MnOを還元するにたる改質剤として、Al屑を
過剰に添加した。これによりスラグ中のT.Fe:1％以下と
なったが、FreeO:550ppmに低下した。RH式真空脱ガス装
置にて、脱炭処理時に脱炭速度が遅く、C:20ppmへの到
達時間が５分延びた。その後、Al脱酸を行ない合金を添
加した。RH式真空脱ガス処理終了時のT.O＝20ppmであっ
た。Comparative example: Molten steel composition at tapping C: 0.03%, FreeO: 730ppm, T. in slag.
Fe: 14% was tapped without deoxidation. Al scrap was added in excess as a modifier to reduce FeO and MnO in the slag on the ladle after tapping. As a result, T.Fe in the slag was reduced to 1% or less, but it was reduced to FreeO: 550ppm. With the RH type vacuum degasser, the decarburization rate was slow during the decarburization process, and the time to reach C: 20ppm was extended by 5 minutes. After that, Al was deoxidized and an alloy was added. At the end of RH type vacuum degassing, TO was 20 ppm.
実施例； 出鋼時の溶鋼成分C:0.03％、FreeO:670ppm、スラグ中T.
Fe:13％で脱酸せずに出鋼した。RH式真空脱ガス装置に
て、この溶鋼を脱炭処理し、C:20ppmに到達後、取鍋上
のスラグ中のFeO,MnOを還元するための改質剤として、A
l屑を過剰に添加するとともに不活性ガスによりスラグ
層のみ攪拌した。これによりスラグ中のT.Fe:1％以下と
なった。同時に、Al脱酸を行ない合金を添加した。RH式
真空脱ガス処理終了時のT.O＝20ppmであった。比較例、
実施例ともに従来例と同様に処理して製品とした。第１
図に示したように溶鋼のT.Oが30ppm以下であれば、介在
物による製品表面欠陥は少なく、実施例においても、介
在物に起因する製品欠陥はなかった。Example: Molten steel composition C: 0.03% at the time of tapping, FreeO: 670 ppm, T. in slag.
Fe: 13% was tapped without deoxidation. This molten steel was decarburized by an RH type vacuum degasser, and after reaching C: 20ppm, as a modifier for reducing FeO and MnO in the slag on the ladle, A
l Waste was added in excess and only the slag layer was stirred with an inert gas. As a result, T.Fe in the slag became 1% or less. At the same time, Al was deoxidized and the alloy was added. At the end of RH type vacuum degassing, TO was 20 ppm. Comparative example,
In each of the examples, products were processed in the same manner as the conventional example. First
As shown in the figure, when the TO of molten steel was 30 ppm or less, there were few product surface defects due to inclusions, and there were no product defects due to inclusions even in the examples.
スラグ中のT.Feは低い方が望ましいが５％以下であれ
ば、T.Oの著しい増加にはならない。It is desirable that the T.Fe content in the slag is low, but if it is 5% or less, the TO content does not increase significantly.
以上説明したように、本発明によれば、極低炭素鋼を製
造するに際し、真空脱炭処理に続いて脱酸処理を行なう
方法において、脱炭処理終了までは、酸化性スラグを取
鍋上に保持し、溶鋼の脱酸を開始すると同時にスラグ還
元剤を添加し攪拌して酸化性スラグを還元することによ
って、脱炭処理が阻害されることなく溶鋼を清浄化で
き、製品品質を向上できるなど極めて有用な効果がもた
らされる。As described above, according to the present invention, when producing ultra-low carbon steel, in a method of performing deoxidation treatment following vacuum decarburization treatment, until the decarburization treatment is completed, the oxidizing slag is placed on the ladle. In order to reduce the oxidizing slag by adding a slag reducing agent and stirring at the same time to start deoxidation of molten steel, the molten steel can be cleaned without hindering the decarburization treatment and the product quality can be improved. Such a very useful effect is brought about.
〈発明の効果〉 本発明方法によると、真空脱ガス装置で脱炭処理が阻害
されることなく、溶鋼が清浄化され、介在物の少ない低
酸素極低炭素鋼を製造することができる。<Effects of the Invention> According to the method of the present invention, it is possible to produce a low-oxygen ultra-low carbon steel in which the molten steel is cleaned and the amount of inclusions is small, without inhibiting the decarburization treatment in the vacuum degassing apparatus.
第１図は、溶鋼中T.Oを介在物起因の製品欠陥との関係
を示すグラフである。FIG. 1 is a graph showing the relationship between TO in molten steel and product defects caused by inclusions.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 黒瀬 芳和 岡山県倉敷市水島川崎通１丁目（番地な し） 川崎製鉄株式会社水島製鉄所内 (56)参考文献 特開 昭63−262412（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshikazu Kurose, Yoshikazu Kurose, Mizushima Kawasaki-dori, 1-chome, Kurashiki City, Okayama Prefecture (No address) Inside the Mizushima Works, Kawasaki Steel Co., Ltd. (56) Reference JP-A 63-262412 (JP, A) )
Claims (1)
ス装置で脱炭処理に続いて脱酸処理を行い、炭素0.002
重量％以下の極低炭素鋼を製造する２次精錬において、
SiO2濃度30重量％未満の高アルミナ質耐火物内張りの取
鍋を使用し脱炭処理までは酸化性スラグを取鍋の溶鋼上
に保持し脱炭処理に続く脱酸処理の開始と同時にスラグ
還元剤を添加し、前記酸化性スラグを攪拌し、還元する
ことによって介在物を低減することを特徴とする低酸素
極低炭素鋼製造方法。1. Carbon 0.002 is obtained by decarburizing the molten steel discharged from a steelmaking furnace to a ladle in a vacuum degassing device, followed by deoxidizing.
In the secondary refining to produce ultra low carbon steel of less than wt%,
Use a ladle with a high-alumina refractory liner with a SiO 2 concentration of less than 30% by weight. Until decarburization, hold the oxidizing slag on the molten steel in the ladle and start deoxidation after the decarburization. A method for producing a low-oxygen extra-low carbon steel characterized in that inclusions are reduced by adding a reducing agent, stirring the oxidizing slag, and reducing it.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1191525A JPH0730388B2 (en) | 1989-07-26 | 1989-07-26 | Low oxygen ultra low carbon steel manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1191525A JPH0730388B2 (en) | 1989-07-26 | 1989-07-26 | Low oxygen ultra low carbon steel manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0356614A JPH0356614A (en) | 1991-03-12 |
| JPH0730388B2 true JPH0730388B2 (en) | 1995-04-05 |
Family
ID=16276113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1191525A Expired - Fee Related JPH0730388B2 (en) | 1989-07-26 | 1989-07-26 | Low oxygen ultra low carbon steel manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0730388B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109988885B (en) * | 2019-05-14 | 2021-04-02 | 鞍钢股份有限公司 | Production method of low-carbon killed steel |
| CN116875770B (en) * | 2023-05-31 | 2025-05-06 | 马鞍山钢铁股份有限公司 | Slag regulator and preparation method and application thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52144316A (en) * | 1976-05-28 | 1977-12-01 | Kawasaki Steel Co | Production of low oxygen* low sulpher steel by handling molten steel in vacuum |
| JPS60152611A (en) * | 1984-01-18 | 1985-08-10 | Nippon Steel Corp | Method for modifying slag |
| JPS63190113A (en) * | 1986-09-25 | 1988-08-05 | Nippon Steel Corp | Production of dead low carbon steel |
| JPS63262412A (en) * | 1987-04-20 | 1988-10-28 | Nippon Steel Corp | Method for cleaning molten steel |
-
1989
- 1989-07-26 JP JP1191525A patent/JPH0730388B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0356614A (en) | 1991-03-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2575827B2 (en) | Manufacturing method of ultra low carbon steel for continuous casting with excellent cleanliness | |
| JP3893770B2 (en) | Melting method of high clean ultra low carbon steel | |
| JP3752801B2 (en) | Method for melting ultra-low carbon and ultra-low nitrogen stainless steel | |
| JP3510989B2 (en) | Refining method of Si alloy iron and stainless steel used for refining stainless steel | |
| JP3473388B2 (en) | Refining method of molten stainless steel | |
| JPH0730388B2 (en) | Low oxygen ultra low carbon steel manufacturing method | |
| JP3282531B2 (en) | Melting method of high clean steel | |
| JPH0488111A (en) | Method for producing dead soft steel | |
| JPH10317049A (en) | Melting method of high clean steel | |
| JP4295836B2 (en) | High cleaning method for Al-containing stainless steel | |
| JPH09310113A (en) | High purification refining method for stainless steel | |
| JP2991796B2 (en) | Melting method of thin steel sheet by magnesium deoxidation | |
| JP3577357B2 (en) | Method for producing ultra-low carbon steel with excellent surface properties | |
| JP3364534B2 (en) | Manufacturing method of high clean steel | |
| JP4354026B2 (en) | Stainless steel manufacturing method | |
| JP2002294327A (en) | High cleanliness steel and its manufacturing method | |
| JP2880842B2 (en) | How to make clean steel | |
| JP3635122B2 (en) | Method for producing ultra-low carbon steel with excellent surface properties | |
| JP2744466B2 (en) | Melting method of high clean ultra low carbon steel | |
| JPH06256836A (en) | High-cleanliness Ultra-low carbon steel melting method | |
| JPH07207327A (en) | Method for producing molten steel for continuous casting | |
| JP2001032014A (en) | Melting method of steel sheet for thin plate | |
| JPH07258720A (en) | Refining method of austenitic stainless steel with excellent hot workability | |
| JPH0649524A (en) | Production of highly clean steel | |
| JP2690350B2 (en) | Highly clean ultra low carbon steel melting method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080405 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090405 Year of fee payment: 14 |
|
| LAPS | Cancellation because of no payment of annual fees |