JPH0733539B2 - Method for producing Al-less weakly deoxidized steel - Google Patents
Method for producing Al-less weakly deoxidized steelInfo
- Publication number
- JPH0733539B2 JPH0733539B2 JP2212672A JP21267290A JPH0733539B2 JP H0733539 B2 JPH0733539 B2 JP H0733539B2 JP 2212672 A JP2212672 A JP 2212672A JP 21267290 A JP21267290 A JP 21267290A JP H0733539 B2 JPH0733539 B2 JP H0733539B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- less
- free oxygen
- treatment
- producing
- 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
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Alレス弱脱酸鋼の製造方法に関するものであ
る。TECHNICAL FIELD The present invention relates to a method for producing Al-less weakly deoxidized steel.
（従来の技術） 従来技術として、第１図に示す従来法で説明する。鋼の
変態核となる10μｍ以下の微小酸化物の個数を増加させ
るため、RHの脱ガス処理中に、鋼中フリー酸素が100ppm
以上の時に、TiやZrなどの弱脱酸元素を投入する。鋼中
フリー酸素の値を制御するために、脱ガス処理にOB処理
を行い、続いてAl投入を行う。(Conventional Technology) As a conventional technology, a conventional method shown in FIG. 1 will be described. In order to increase the number of fine oxides of 10 μm or less that become the transformation nuclei of steel, 100 ppm of free oxygen in the steel during degassing of RH
At the above time, a weak deoxidizing element such as Ti or Zr is added. In order to control the value of free oxygen in steel, OB treatment is performed as degassing treatment, and then Al is introduced.
（発明が解決しようとする課題） 本発明の課題を、従来法を示す第２図により説明する。
微小酸化物の個数を増加させるために、RH脱ガス処理中
に、鋼中フリー酸素が100ppm以上で弱脱酸元素を投入す
る従来法を実施すると、弱脱酸元素と平衡になるまで、
鋼中フリー酸素が減少し、従来法に示すように、Al2O3
やTiO系の脱酸生成物量が増加し、これが鋳片上面側に
集積し、UST不合の原因となる。(Problems to be Solved by the Invention) The problems of the present invention will be described with reference to FIG. 2 showing a conventional method.
In order to increase the number of small oxides, during the RH degassing process, when the conventional method of introducing a weak deoxidizing element with free oxygen in the steel of 100 ppm or more is carried out, until it becomes in equilibrium with the weak deoxidizing element,
Free oxygen in steel decreases, and as shown in the conventional method, Al 2 O 3
The amount of TiO-based deoxidation products increases, which accumulates on the upper surface of the slab and causes UST failure.
（課題を解決するための手段） 本発明は前記の課題を有利に解決するものであって、そ
の要旨は溶鋼のRH処理前に、取鍋内に生石灰を投入し、
スラグ中のT.Feを２％以下にならしめ、Al;0.001％以下
で鋼中フリー酸素を100ppm以下にし、RH処理中には、脱
ガスにより鋼中フリー酸素を50ppm以下まで処理し、そ
の後Ti（Zr）を投入し、RH処理後には、Al;10ppm以下で
鋼中フリー酸素を30ppm以下とすることを特徴とするAl
レス弱脱酸鋼の製造方法にある。(Means for Solving the Problem) The present invention advantageously solves the above problems, and its gist is to add quick lime into a ladle before RH treatment of molten steel,
T.Fe in the slag is leveled to 2% or less, Al; 0.001% or less to reduce the free oxygen in the steel to 100 ppm or less, and during RH treatment, the free oxygen in the steel is treated to 50 ppm or less by degassing, and then After Ti (Zr) is charged and after RH treatment, Al; 10 ppm or less and free oxygen in steel is 30 ppm or less
It is in the method for manufacturing less weakly deoxidized steel.
以下図面に基づいて本発明を説明する。The present invention will be described below with reference to the drawings.
本発明で用いる鋼種の成分系を表１（最終製品の成分
系）で示す。特にAlに関しては、Al末脱酸状態であり、
TiはＯとＮにバランスするように微量添加する。The composition system of steel types used in the present invention is shown in Table 1 (composition system of final product). Especially for Al, Al powder is in a deoxidized state,
Ti is added in a trace amount so as to balance O and N.
本発明の方法を第１図で説明する。RH脱ガス処理中に、
OB処理を行なわず、またAl投入を行わず、またAlの混入
の原因となる組成中にAlを含む合金元素の添加は、RH脱
ガス処理前に行う。また、RH処理前に、生石灰を投入
し、取鍋スラグのT.Fe濃度を希釈するとともに、スラグ
の流動性を低減し、スラグによる溶鋼の再酸化を防止す
る。RH脱ガス処理中に、数分毎に鋼中フリー酸素を測定
し、鋼中フリー酸素の降下がなくなり始めた時点で弱脱
酸元素を投入する。The method of the present invention will be described with reference to FIG. During the RH degassing process,
OB treatment is not performed, Al is not introduced, and addition of an alloying element containing Al in the composition that causes mixing of Al is performed before the RH degassing treatment. Before the RH treatment, quick lime is added to dilute the T.Fe concentration in the ladle slag, reduce the fluidity of the slag, and prevent re-oxidation of molten steel by the slag. During the RH degassing process, the free oxygen in the steel is measured every few minutes, and a weak deoxidizing element is added when the free oxygen in the steel begins to drop.
本発明の方法の効果を本発明を示す第２図で説明する。
弱脱酸元素の投入時の酸素値が低いため、TiO系の脱酸
生成物量が減少し、UST不合となる鋳片上面側に集積す
る介在物が減少する。The effect of the method of the present invention will be described with reference to FIG. 2 showing the present invention.
Since the oxygen value at the time of adding the weak deoxidizing element is low, the amount of TiO-based deoxidizing products is reduced, and the inclusions accumulated on the upper surface side of the slab, which are UST unsuitable, are reduced.
本発明の方法を可能とさせた考え方を以下に示す。The concept that enables the method of the present invention is shown below.
鋼の変態核となる微小酸化物の生成理論より、鋼中Sol.
Alが10ppm以下の状態では、凝固温度で弱脱酸元素と平
衡する酸素値が10μｍ以下の酸化物個数を決めるため、
RH脱ガス処理での弱脱酸元素投入から鋳片凝固までの脱
酸生成物量には微小酸化物個数は影響しないことが判明
した。また、UST不合の発生原因が脱酸材投入時点から
凝固時点までに成長した脱酸生成物が介在物となってい
ることであることが介在物組成分析結果より判明した。
そこで、Alレス弱脱酸鋼の製造においては、鋼中Sol.Al
を10ppm以下および鋼中フリー酸素を100ppm以下を目標
とした。Based on the theory of formation of small oxides that serve as transformation nuclei in steel, Sol.
When the Al content is 10 ppm or less, the number of oxides whose oxygen value in equilibrium with the weak deoxidizing element at the solidification temperature is 10 μm or less is determined.
It was found that the number of small oxides did not affect the amount of deoxidation products from the addition of weak deoxidation elements to solidification of the slab in the RH degassing process. In addition, it was revealed from the inclusion composition analysis result that the cause of the UST incompatibility was that the deoxidized product grown from the time of introducing the deoxidizer to the time of solidification was the inclusion.
Therefore, when manufacturing Al-less weakly deoxidized steel, Sol.Al
Was set to 10 ppm or less and free oxygen in steel set to 100 ppm or less.
（発明の効果） 第３図は、従来法と本発明法のUST不合発生率を示した
ものであるが、本発明により、UST不合発生率はほとん
ど皆無となった。 (Effects of the Invention) FIG. 3 shows the UST incompatibility occurrence rates of the conventional method and the method of the present invention, but the present invention makes almost no UST incompatibility occurrence rate.
【図面の簡単な説明】 第１図は、本発明によるRH脱ガス時間と鋼中フリー
〔Ｏ〕との関係を従来法と比較して示す図、第２図は、
本発明による脱酸生成物に消費される〔Ｏ〕の内訳を従
来法と比較して示す図、第３図はUST不合発生率を示す
図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between the RH degassing time and free [O] in steel according to the present invention in comparison with the conventional method, and FIG.
The figure which shows the breakdown of [O] consumed by the deoxidation product by this invention compared with the conventional method, and FIG. 3 is a figure which shows UST incompatibility occurrence rate.
Claims (1)
し、スラグ中のT.Feを２％以下にならしめ、Al;0.001％
以下で鋼中フリー酸素を100ppm以下にし、RH処理中に
は、脱ガスにより鋼中フリー酸素を50ppm以下まで処理
し、その後Ti（Zr）を投入し、RH処理後には、Al;10ppm
以下で鋼中フリー酸素を30ppm以下とすることを特徴と
するAlレス弱脱酸鋼の製造方法。1. Before the RH treatment of molten steel, quick lime is put into the ladle to level T.Fe in the slag to 2% or less, Al; 0.001%
Free oxygen in steel is set to 100ppm or less in the following, and free oxygen in steel is processed to 50ppm or less by degassing during RH treatment, then Ti (Zr) is added, and after RH treatment, Al; 10ppm
A method for producing an Al-less weakly deoxidized steel characterized in that the free oxygen in the steel is set to 30 ppm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2212672A JPH0733539B2 (en) | 1990-08-11 | 1990-08-11 | Method for producing Al-less weakly deoxidized steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2212672A JPH0733539B2 (en) | 1990-08-11 | 1990-08-11 | Method for producing Al-less weakly deoxidized steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0499216A JPH0499216A (en) | 1992-03-31 |
| JPH0733539B2 true JPH0733539B2 (en) | 1995-04-12 |
Family
ID=16626489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2212672A Expired - Fee Related JPH0733539B2 (en) | 1990-08-11 | 1990-08-11 | Method for producing Al-less weakly deoxidized steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0733539B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040046397A (en) * | 2002-11-27 | 2004-06-05 | 주식회사 포스코 | Degassing process of molten steel by making an analysis of slag |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5735243A (en) * | 1980-08-11 | 1982-02-25 | Kyokuto Denki Kk | Hot air flow type heating apparatus |
| JPS621811A (en) * | 1985-06-26 | 1987-01-07 | Nippon Steel Corp | Manufacture of rail having superior damage resistance |
-
1990
- 1990-08-11 JP JP2212672A patent/JPH0733539B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0499216A (en) | 1992-03-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |