JP2000129336A - Melting method for high cleanliness steel - Google Patents
Melting method for high cleanliness steelInfo
- Publication number
- JP2000129336A JP2000129336A JP10309805A JP30980598A JP2000129336A JP 2000129336 A JP2000129336 A JP 2000129336A JP 10309805 A JP10309805 A JP 10309805A JP 30980598 A JP30980598 A JP 30980598A JP 2000129336 A JP2000129336 A JP 2000129336A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- cao
- slag
- inclusions
- mgo
- 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
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、高清浄度鋼の溶製
方法に関し、とくに介在物量の低減と微細化に有効な転
炉出鋼溶鋼の精製技術を提案する。なお、本発明は、軸
受材料やＳＣ材などとして用いられる高清浄度鋼の製造
に適用される方法である。The present invention relates to a method for smelting high cleanliness steel, and particularly to a technique for purifying molten steel from a converter steel which is effective in reducing the amount of inclusions and miniaturization. The present invention is a method applied to the production of high cleanliness steel used as a bearing material or SC material.
【０００２】[0002]
【従来の技術】軸受材料などに用いられる高清浄度鋼を
溶製する方法としては、アーク加熱を行いながら長時間
攪拌 (ＬＦ法) した後、真空脱ガス処理を行う方法や、
特開昭57−73118 号公報に開示されているような、いわ
ゆるＲＨ真空脱ガス処理を長時間行う方法などが知られ
ている。しかし、これらの方法では、全酸素濃度の低下
は達成されるものの、粗大な (＞10〜20μm)酸化物系介
在物を含有していることから、例えば、軸受材料に適用
される転動疲労寿命試験を行うと、必ずしもよい結果
(長寿命) が得られないという問題があった。2. Description of the Related Art As a method of melting high-purity steel used for bearing materials and the like, a method of performing stirring for a long time (LF method) while performing arc heating, followed by vacuum degassing,
A method of performing a so-called RH vacuum degassing process for a long time, as disclosed in Japanese Patent Application Laid-Open No. 57-73118, is known. However, although these methods achieve a reduction in total oxygen concentration, they contain coarse (> 10 to 20 μm) oxide-based inclusions. Life tests do not always give good results
(Long service life) cannot be obtained.
【０００３】その他、高清浄度鋼を溶製する方法として
は、特開平 1−222012号公報に開示されているような、
溶鋼にCa−Siを添加して介在物の形態制御を行う方法
や、特開平４−333359号公報に開示されているような、
金属Mgを添加して介在物の形態制御を行う方法もある。
しかし、これらの方法はCaやMgを合金や単体のまま添加
しているため、CaやMgの濃度が局所的に高くなる部分が
あり、その部分ではCaＯやMgＯ濃度の高い粗大な介在物
が不可避に生成し、これが前記転動疲労寿命を低下させ
る原因となっていた。[0003] Other methods for melting high cleanliness steel include those disclosed in Japanese Patent Application Laid-Open No. 1-222012.
A method for controlling the form of inclusions by adding Ca-Si to molten steel, as disclosed in JP-A-4-333359,
There is also a method of controlling the form of inclusions by adding metal Mg.
However, in these methods, since Ca or Mg is added as an alloy or a simple substance, there is a portion where the concentration of Ca or Mg is locally increased, and coarse inclusions having a high CaO or MgO concentration are present in those portions. Inevitably formed, which has caused a reduction in the rolling fatigue life.
【０００４】[0004]
【発明が解決しようとする課題】上述したように従来技
術は、鋼中酸素濃度の低下には有効でも、軸受鋼の転動
疲労寿命が向上しないとか、CaＯやMgＯ濃度が局部的に
高く粗大な介在物の生成を阻止できないという課題を抱
えていた。そこで、本発明の目的は、従来技術が抱えて
いる上述した課題を解決できる技術を提案すること、と
くに鋼中介在物量が少なくかつ介在物粒径の小さい長疲
労寿命の高清浄度鋼を製造するための溶製技術を提案す
ることにある。As described above, although the prior art is effective in lowering the oxygen concentration in steel, it does not improve the rolling fatigue life of the bearing steel, or the CaO or MgO concentration is locally high and coarse. However, there is a problem that the generation of a large inclusion cannot be prevented. Therefore, an object of the present invention is to propose a technology capable of solving the above-mentioned problems of the conventional technology, and in particular, to produce a long-lifetime high-cleanliness steel with a small amount of inclusions in the steel and a small particle size of the inclusions. It is to propose a smelting technique for performing the above.
【０００５】[0005]
【課題を解決するための手段】上掲の目的実現に向けた
研究において、発明者らは、軸受鋼などの分野において
必要とされる長疲労寿命特性を有する高清浄度鋼の溶製
に当たっては、鋼中介在物量を低下させるとともに、粗
大な介在物を減少させることが重要であるとの知見を得
た。とくに、Al2O3 やこのAl2O3 を主成分としてCaＯや
MgＯを含む粗大な介在物を減少させることが重要である
ことがわかった。このような課題に対して本発明では、
転炉から取鍋に出鋼した溶鋼に、MgＯ、CaＯ、Al2O3 を
主成分とする混合フラックスを添加し、このことによっ
てSiO2を１０wt％以下、MgＯを１５〜２５wt％、Al2O3
を３０〜４５wt％およびCaＯを３５〜５０wt％含有する
スラグを調整し、このようなスラグを生成させた取鍋内
溶鋼を不活性ガスによる攪拌処理を行い、その後ＲＨ脱
ガス処理を行うようにしたことを特徴とする高清浄度鋼
を溶製する方法を提案する。SUMMARY OF THE INVENTION In the research aimed at realizing the above-mentioned object, the present inventors have found that when purifying high cleanliness steel having a long fatigue life characteristic required in the field of bearing steel and the like, the present inventors have found that: It was found that it is important to reduce the amount of inclusions in steel and to reduce coarse inclusions. In particular, CaO Ya the as Al 2 O 3 and this for Al 2 O 3 main components
It has been found that it is important to reduce coarse inclusions including MgO. In the present invention for such a problem,
The molten steel was tapped to a ladle from a converter furnace, MgO, CaO, added flux mixture composed mainly of Al 2 O 3, 10wt% of SiO 2 by this less, 15-25 wt% of MgO, Al 2 O 3
Slag containing 30 to 45 wt% of CaO and 35 to 50 wt% of CaO is prepared, and the molten steel in the ladle in which such slag is generated is subjected to a stirring treatment with an inert gas, followed by an RH degassing treatment. We propose a method of melting high cleanliness steel characterized by the following.
【０００６】[0006]
【発明の実施の形態】一般に、高清浄度鋼を溶製する場
合、介在物の吸収能を増加させるために、スラグ中のCa
Ｏ／Al2O3 を大きくすることが有効であると考えられて
きた。しかし、発明者らの研究によれば、鋼中に残留す
る粗大な介在物というのは、多くはAl 2O3 またはこのAl
2O3 とともにCaＯやMgＯを含む介在物であり、これが軸
受鋼などの転動疲労寿命を悪くする原因であり、そのよ
うな介在物を減少させることこそが高清浄度鋼を得るポ
イントであることがわかった。また、この研究を通じ、
CaＯを含む鋼中介在物におけるCaＯ濃度は、スラグ中Ca
Ｏ濃度に比べると非常に低く、それ故にスラグの巻き込
みにより生成したものではないと推定された。また、ス
ラグ中の組成と介在物形態の調査において、スラグ中の
CaＯ濃度が高すぎる場合に限って、鋼中介在物の含有が
認められることもわかった。こうした一連の実験結果に
より、発明者らは、粗大介在物を生成させることなく、
疲労寿命特性に優れた高清浄度鋼を溶製するための最適
スラグ組成を開発したのである。DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, a place where high cleanliness steel is melted
In order to increase the absorption capacity of inclusions,
O / AlTwoOThreeIs considered to be effective
Came. However, according to the inventors' research, it has been found that
Coarse inclusions are mostly Al TwoOThreeOr this Al
TwoOThreeTogether with CaO and MgO-containing inclusions
This is the cause of shortening the rolling fatigue life of steel bearings.
Reducing inclusions is the key to obtaining high cleanliness steel.
It turned out to be int. Also, through this research,
The CaO concentration in inclusions in steel containing CaO is
Very low compared to O concentration, therefore slag entrainment
It was presumed that it was not generated only by Also,
In investigating the composition and inclusion morphology in the lag,
Only when the CaO concentration is too high, the inclusion of inclusions in the steel
I also found it to be acceptable. These series of experimental results
Thus, the inventors, without generating coarse inclusions,
Optimum for melting high cleanliness steel with excellent fatigue life characteristics
The slag composition was developed.
【０００７】さて、本発明の高清浄度鋼の溶製方法にお
いて、上述した所要の成分組成に調整されたスラグを有
する溶鋼を不活性ガスで攪拌し、その後引き続きＲＨ真
空脱ガス処理を行うと、精製溶鋼中には微細なMgＯ・Al
2O3 系介在物を生成させることができ、所期した清浄度
の高い溶鋼を得ることができる。[0007] In the method of smelting high cleanliness steel of the present invention, the molten steel having the slag adjusted to the required composition described above is stirred with an inert gas, and then RH vacuum degassing is performed. , Fine MgO / Al in refined molten steel
2 O 3 -based inclusions can be generated, and the expected high cleanness of molten steel can be obtained.
【０００８】ここで、上記生成スラグ中のMgＯ濃度が低
すぎると、介在物中にAl2O3 を生成し、その介在物の一
部が粗大な介在物として存在するため、寿命の低下を引
き起こす。また、MgＯの濃度が高すぎる場合、スラグ中
に固相部分が多くなり、フラックスが有効利用されない
ばかりでなく、介在物の吸収能が減少し清浄性の悪化、
寿命の低下を引き起こす。一方、SiO2濃度が高すぎる場
合も、SiO2による再酸化で溶鋼の清浄性が低下し、ま
た、CaＯ濃度が高すぎる場合には、Al2O3 −CaＯ系の粗
大な介在物を生成することとなる。従って、清浄性が高
く粗大な介在物が存在しない高清浄度鋼の製造というの
は、CaＯ、MgＯ、SiO2濃度をともに規制したスラグを用
いて溶製することが必要である。Here, if the MgO concentration in the produced slag is too low, Al 2 O 3 is generated in the inclusions, and some of the inclusions are present as coarse inclusions. cause. Also, if the concentration of MgO is too high, the solid phase portion in the slag increases, not only the flux is not effectively used, but also the absorption capacity of inclusions decreases and the cleanliness deteriorates,
Causes shorter life. On the other hand, when the SiO 2 concentration is too high, the cleanliness of the molten steel is reduced by re-oxidation with SiO 2 , and when the CaO concentration is too high, coarse inclusions of Al 2 O 3 -CaO are generated. Will be done. Therefore, the production of high cleanliness steel with high cleanliness and no coarse inclusions requires melting using slag in which the concentrations of CaO, MgO and SiO 2 are both regulated.
【０００９】[0009]
【実施例】本発明の実施例を説明する。ここでは、Ｃ＝
0.98〜1.03wt％、Si＝0.2 〜0.3wt％、Cr＝1.3 〜1.6 w
t％、Al＝0.02〜0.05wt％の転炉出鋼後の溶鋼 180〜200
ｔ用いて実験を行った。その結果を比較例とともに表１
に示す。実施例では、上記溶鋼を転炉から取鍋に出鋼し
た後、フラックスを 2.5〜3.0ｔ添加した。このフラッ
クスの組成は、CaＯを30〜40wt％、Al2O3 を40〜50wt
％、MgＯを15〜30wt％含むものを用いた。上記フラック
スを添加しスラグを生成させるための溶鋼の攪拌には、
Arガス流量3 〜3.5 Nm3/min で４〜８分処理し、その後
ＲＨ真空脱ガス装置で30分間処理を行った。実施例のス
ラグ組成は表１に示すとおり、SiO2＝７〜９wt％、MgＯ
＝15〜21wt％、CaＯ＝36〜49wt％であった。An embodiment of the present invention will be described. Here, C =
0.98 to 1.03 wt%, Si = 0.2 to 0.3 wt%, Cr = 1.3 to 1.6 w
t%, molten steel 180-200
The experiment was performed using t. Table 1 shows the results together with comparative examples.
Shown in In the example, after the molten steel was tapped from a converter to a ladle, 2.5 to 3.0 tons of flux was added. The composition of this flux is such that CaO is 30 to 40 wt%, and Al 2 O 3 is 40 to 50 wt%.
%, MgO containing 15 to 30% by weight. For stirring the molten steel to generate slag by adding the above flux,
The treatment was performed at an Ar gas flow rate of 3 to 3.5 Nm 3 / min for 4 to 8 minutes, and thereafter, the treatment was performed for 30 minutes by an RH vacuum degassing apparatus. As shown in Table 1, the composition of the slag in the examples is as follows: SiO 2 = 7 to 9 wt%, MgO
= 15 to 21 wt%, and CaO = 36 to 49 wt%.
【００１０】比較例では、添加フラックスとして、CaＯ
を40wt％、Al2O3 を40wt％、MgＯを20wt％含むものを1.
5 t 添加し、スラグ生成後のSiO2濃度が12wt％と高かっ
たもの (比較例１) 、CaＯが60wt％、Al2O3 が40wt％の
スラグを3t添加し、MgＯ濃度が低かった場合 (比較例
２) である。一方、実施例においては、溶鋼中全酸素量
は4 〜6 ppm と低く、かつ介在物粒径を測定したとこ
ろ、320 mm2 あたりの最大径は、全て10μm 以下であっ
た。一方、比較例１では、SiO2濃度が高かったため、全
酸素量が12ppm と高くなった。また、320 mm2 あたりの
最大介在物粒径も12.5μm と大きかった。また、比較例
２においては、全酸素量は６ppm と低かったが、最大介
在物径は15μm と大きかった。この介在物はCaＯを含有
していることが確認された。このように、各実施例の方
法を用いることにより、全酸素量が低く、最大介在物粒
径が小さな高清浄度鋼が溶製できることが確かめられ
た。In the comparative example, the added flux was CaO
Containing 40 wt%, 40 wt% of Al 2 O 3 and 20 wt% of MgO.
5 t was added, what is SiO 2 concentration after formation of slag was as high as 12 wt% (Comparative Example 1), CaO is 60 wt%, when Al 2 O 3 is added 3t of 40 wt% of the slag was less MgO concentration (Comparative Example 2). On the other hand, in the examples, the total oxygen content in the molten steel was as low as 4 to 6 ppm, and when the particle diameter of the inclusions was measured, the maximum diameter per 320 mm 2 was all 10 μm or less. On the other hand, in Comparative Example 1, since the SiO 2 concentration was high, the total oxygen amount was as high as 12 ppm. Further, the maximum inclusion particle size per 320 mm 2 was as large as 12.5 μm. In Comparative Example 2, the total oxygen content was as low as 6 ppm, but the maximum inclusion diameter was as large as 15 μm. It was confirmed that this inclusion contained CaO. Thus, it was confirmed that by using the method of each example, a high cleanliness steel having a low total oxygen content and a small maximum inclusion particle size can be produced.
【００１１】[0011]
【表１】 [Table 1]
【００１２】[0012]
【発明の効果】以上説明したように本発明によれば、介
在物量が少なくかつ介在物粒径の小さな高清浄度鋼の溶
製が可能となった。As described above, according to the present invention, it is possible to smelt high cleanliness steel having a small amount of inclusions and a small particle size of inclusions.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 戸澤 宏一 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 Ｆターム(参考） 4K013 AA07 BA14 CA02 CC01 CE01 CE05 CE07 EA03 EA05 FA02 FA05 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Tozawa 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. FA02 FA05
Claims (1)
物を除去することにより高清浄度鋼を製造する方法にお
いて、前記出鋼溶鋼にMgＯ、CaＯ、Al2O3 を主成分とす
る混合フラックスを添加して、SiO2を１０wt％以下、Mg
Ｏを１５〜２５wt％、Al2O3 を３０〜４５wt％およびCa
Ｏを３５〜５０wt％含有する組成のスラグを生成させ、
次いで、このようなスラグ成分に調整した取鍋内溶鋼を
不活性ガスによる攪拌処理を行い、その後ＲＨ真空脱ガ
ス処理を行うことを特徴とする高清浄度鋼の溶製方法。1. A method for producing a high-cleanliness steel by removing inclusions during vacuum degassing treatment of a molten tapping steel, wherein the molten tapping steel contains MgO, CaO, and Al 2 O 3 as main components. Add flux and make SiO 2 less than 10wt%, Mg
15 to 25 wt% of O, 30 to 45 wt% of Al 2 O 3 and Ca
A slag having a composition containing 35 to 50% by weight of O is produced,
Then, the molten steel in the ladle adjusted to such a slag component is subjected to an agitation treatment with an inert gas, and then an RH vacuum degassing treatment is performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30980598A JP3896709B2 (en) | 1998-10-30 | 1998-10-30 | Method of melting high cleanliness steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30980598A JP3896709B2 (en) | 1998-10-30 | 1998-10-30 | Method of melting high cleanliness steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000129336A true JP2000129336A (en) | 2000-05-09 |
| JP3896709B2 JP3896709B2 (en) | 2007-03-22 |
Family
ID=17997467
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30980598A Expired - Fee Related JP3896709B2 (en) | 1998-10-30 | 1998-10-30 | Method of melting high cleanliness steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3896709B2 (en) |
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|---|---|---|---|---|
| JP2003155516A (en) * | 2001-11-15 | 2003-05-30 | Kawasaki Steel Corp | Method for desulfurizing molten steel with ladle- refining |
| KR100723302B1 (en) | 2006-10-25 | 2007-05-31 | 지엠티 엔 티 주식회사 | Tundish and ladle flux for the basic liner system |
| CN100378242C (en) * | 2004-12-09 | 2008-04-02 | 株式会社神户制钢所 | Highly ductile steel sheet and method of manufacturing the same |
| JP2008133505A (en) * | 2006-11-28 | 2008-06-12 | Kobe Steel Ltd | Method for manufacturing high cleanliness steel |
| WO2008081763A1 (en) * | 2006-12-22 | 2008-07-10 | Yoshizawa Lime Industry Co., Ltd. | Flux for obtaining steel reduced in nitrogen, oxygen, and sulfur contents through smelting |
| WO2008149733A1 (en) * | 2007-06-05 | 2008-12-11 | Kabushiki Kaisha Kobe Seiko Sho | Process for producing high cleanliness steel |
| JP2010196114A (en) * | 2009-02-25 | 2010-09-09 | Jfe Steel Corp | Method for producing bearing steel |
| KR101009895B1 (en) | 2008-07-25 | 2011-01-20 | 현대제철 주식회사 | Method for preventing slag over flow of vacuum refining process |
| JP2012509243A (en) * | 2008-11-19 | 2012-04-19 | ケルネオ | Porous magnesia-containing clinker, its production method and its use as a fluxing agent for steel slag treatment |
| CN102876851A (en) * | 2012-10-08 | 2013-01-16 | 武汉钢铁(集团)公司 | Method for improving calcium yield of RH vacuum furnace |
| JP2013023739A (en) * | 2011-07-22 | 2013-02-04 | Nippon Steel & Sumitomo Metal Corp | High cleanliness bearing steel and method for producing the same |
| JPWO2018109900A1 (en) * | 2016-12-15 | 2018-12-20 | 株式会社トライテック | Fuel supply system |
| CN109702158A (en) * | 2019-01-21 | 2019-05-03 | 湖南工业大学 | A kind of high-aluminum steel protective slag for continuous casting and its preparation method and application |
-
1998
- 1998-10-30 JP JP30980598A patent/JP3896709B2/en not_active Expired - Fee Related
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003155516A (en) * | 2001-11-15 | 2003-05-30 | Kawasaki Steel Corp | Method for desulfurizing molten steel with ladle- refining |
| CN100378242C (en) * | 2004-12-09 | 2008-04-02 | 株式会社神户制钢所 | Highly ductile steel sheet and method of manufacturing the same |
| KR100723302B1 (en) | 2006-10-25 | 2007-05-31 | 지엠티 엔 티 주식회사 | Tundish and ladle flux for the basic liner system |
| JP4641022B2 (en) * | 2006-11-28 | 2011-03-02 | 株式会社神戸製鋼所 | Manufacturing method of high cleanliness steel |
| JP2008133505A (en) * | 2006-11-28 | 2008-06-12 | Kobe Steel Ltd | Method for manufacturing high cleanliness steel |
| WO2008081763A1 (en) * | 2006-12-22 | 2008-07-10 | Yoshizawa Lime Industry Co., Ltd. | Flux for obtaining steel reduced in nitrogen, oxygen, and sulfur contents through smelting |
| WO2008149733A1 (en) * | 2007-06-05 | 2008-12-11 | Kabushiki Kaisha Kobe Seiko Sho | Process for producing high cleanliness steel |
| KR101009895B1 (en) | 2008-07-25 | 2011-01-20 | 현대제철 주식회사 | Method for preventing slag over flow of vacuum refining process |
| JP2012509243A (en) * | 2008-11-19 | 2012-04-19 | ケルネオ | Porous magnesia-containing clinker, its production method and its use as a fluxing agent for steel slag treatment |
| JP2010196114A (en) * | 2009-02-25 | 2010-09-09 | Jfe Steel Corp | Method for producing bearing steel |
| JP2013023739A (en) * | 2011-07-22 | 2013-02-04 | Nippon Steel & Sumitomo Metal Corp | High cleanliness bearing steel and method for producing the same |
| CN102876851A (en) * | 2012-10-08 | 2013-01-16 | 武汉钢铁(集团)公司 | Method for improving calcium yield of RH vacuum furnace |
| JPWO2018109900A1 (en) * | 2016-12-15 | 2018-12-20 | 株式会社トライテック | Fuel supply system |
| CN109702158A (en) * | 2019-01-21 | 2019-05-03 | 湖南工业大学 | A kind of high-aluminum steel protective slag for continuous casting and its preparation method and application |
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