JPH0310015A - Method for refining molten steel - Google Patents
Method for refining molten steelInfo
- Publication number
- JPH0310015A JPH0310015A JP1144956A JP14495689A JPH0310015A JP H0310015 A JPH0310015 A JP H0310015A JP 1144956 A JP1144956 A JP 1144956A JP 14495689 A JP14495689 A JP 14495689A JP H0310015 A JPH0310015 A JP H0310015A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- slag
- molten
- converter
- cao
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 72
- 239000010959 steel Substances 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000007670 refining Methods 0.000 title claims description 12
- 239000002893 slag Substances 0.000 claims abstract description 39
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 22
- 238000007872 degassing Methods 0.000 abstract description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 7
- 239000000203 mixture Substances 0.000 abstract description 5
- 238000010079 rubber tapping Methods 0.000 abstract description 5
- 239000000377 silicon dioxide Substances 0.000 abstract description 4
- 229910052681 coesite Inorganic materials 0.000 abstract 3
- 229910052593 corundum Inorganic materials 0.000 abstract 3
- 229910052906 cristobalite Inorganic materials 0.000 abstract 3
- 235000012239 silicon dioxide Nutrition 0.000 abstract 3
- 229910052682 stishovite Inorganic materials 0.000 abstract 3
- 229910052905 tridymite Inorganic materials 0.000 abstract 3
- 238000009849 vacuum degassing Methods 0.000 abstract 3
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 3
- 230000001590 oxidative effect Effects 0.000 abstract 2
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 229910002974 CaO–SiO2 Inorganic materials 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 241000219112 Cucumis Species 0.000 description 1
- 235000015510 Cucumis melo subsp melo Nutrition 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- FJJCIZWZNKZHII-UHFFFAOYSA-N [4,6-bis(cyanoamino)-1,3,5-triazin-2-yl]cyanamide Chemical compound N#CNC1=NC(NC#N)=NC(NC#N)=N1 FJJCIZWZNKZHII-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000009628 steelmaking Methods 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)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、アルミナ等の介在物を低減した清浄鋼を溶製
するための溶鋼の精錬方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for refining molten steel for producing clean steel with reduced inclusions such as alumina.
［従来の技術］
転炉出鋼された溶鋼は、多量の［０コを含むため、出鋼
時またはそれ以降の二次精錬時に、溶鋼に金属アルミニ
ウム等の脱酸剤を添加して、脱酸処理される。脱酸処理
された溶鋼は、その後、種々の処理工程を経て、鋳造さ
れる。[Prior art] Since molten steel tapped from a converter contains a large amount of [0], a deoxidizing agent such as metallic aluminum is added to the molten steel during tapping or subsequent secondary refining. Acid treated. The deoxidized molten steel is then subjected to various treatment steps and then cast.
一般に、鋳造溶鋼中の介在物量が増えると、これを鋳造
した場合に鋳片に表面疵が生じ、品質および製品歩留り
の低下を招く。このため、転炉出鋼された溶鋼は、製鋼
工場から鋳造工場に至るま、での間に、種々の精錬工程
を経て、介在物が除去される。Generally, when the amount of inclusions in cast molten steel increases, surface flaws occur in the slab when it is cast, leading to a decrease in quality and product yield. For this reason, molten steel tapped from a converter undergoes various refining processes during its journey from a steelmaking factory to a foundry to remove inclusions.
［発明が解決しようとする課題］
しかしながら、従来の精錬方法においては、脱酸処理に
より生じた多量の脱酸生成物（アルミナ等）が溶鋼中に
存在し、これが積極的に除去されることなく後工程まで
持ち込まれるので、鋳造溶鋼の［０］ ｌｉｔが高レベ
ルとなる。このため、鋳片の酸素含有量が高まり、介在
物を除去しているにも拘らず、アルミナ等の介在物に起
因する鋳片表面疵が多発する。この結果、鋳片表面の手
入れ作業が増加し、製品の品質および歩留りが低下する
という聞届点があった。[Problem to be solved by the invention] However, in the conventional refining method, a large amount of deoxidation products (alumina, etc.) generated by the deoxidation treatment are present in the molten steel, and these are not actively removed. Since it is carried into the subsequent process, the [0] lit of the cast molten steel becomes high. As a result, the oxygen content of the slab increases, and despite the removal of inclusions, many surface defects occur on the slab due to inclusions such as alumina. As a result, the work required to clean the surface of the cast slab increases, resulting in a decrease in product quality and yield.
この発明は、上記事情に鑑みてなされたものであって、
溶鋼中の介在物を低減して、清浄な溶鋼を得ることがで
きる溶鋼の精錬方法を提供することを目的とする。This invention was made in view of the above circumstances, and
It is an object of the present invention to provide a method for refining molten steel that can reduce inclusions in molten steel and obtain clean molten steel.
［課題を解決するための手段］
この発明に係る溶鋼の精錬方法は、溶鋼中の脱酸生成物
と反応しうる成分を含むスラグを、転炉出鋼された溶鋼
に添加することを特徴とする。[Means for Solving the Problems] A method for refining molten steel according to the present invention is characterized in that slag containing a component that can react with deoxidation products in molten steel is added to molten steel discharged from a converter. do.
溶鋼中の脱酸生成物と反応しうる成分を含むスラグは、
石灰およびシリカをほぼ１：１の割合で含む塩基度が工
程度のスラグであることが好ましい。この場合に、Ｃａ
ＯおよびＳｉＯ□が、それぞれ５０±５重量％の範囲内
にあることが望ましい。Slag containing components that can react with deoxidation products in molten steel is
Preferably, it is a process basicity slag containing lime and silica in an approximately 1:1 ratio. In this case, Ca
It is desirable that O and SiO□ are each in the range of 50±5% by weight.
また、スラグを溶鋼に添加する時期としては、転炉出鋼
時又はその後の二次精錬時であることが好ましい。Further, the timing of adding slag to molten steel is preferably at the time of tapping the steel from the converter or during the subsequent secondary refining.
［作用］
溶鋼中のアルミナ量および［０］ｆｆｉは相互に密接な
相関関係があり、［０］量が高いレベルにあると、溶鋼
中のアルミナ量が増え、鋳片品質に重大な影響を及ぼす
。溶鋼を脱酸処理すると、これによって生じたアルミナ
は湯面に浮上したとしても積極的に除去されず、そのま
ま溶鋼中に飽和状態で存在する。このため、溶鋼中の［
０］量はある一定のレベル以下には低下せず、溶鋼中の
［０］量およびアルミナ量の両者は平衡する。[Effect] The amount of alumina in molten steel and [0]ffi have a close correlation with each other, and when the amount of [0] is at a high level, the amount of alumina in molten steel increases, which has a serious effect on the quality of the slab. affect When molten steel is deoxidized, the resulting alumina is not actively removed even if it floats to the surface of the molten steel, and remains in the molten steel in a saturated state. For this reason, [
The amount of [0] does not decrease below a certain level, and both the amount of [0] and the amount of alumina in the molten steel are in equilibrium.
この発明に係る溶鋼の精錬方法においては、出鋼後の溶
鋼にスラグを添加して、アルミナを溶鋼からスラグに積
極的に移行させる。添加スラグは、溶鋼上に上置きする
だけで十分に溶融する。溶融スラグにアルミナの一部が
吸収され、アルミナの飽和状態が解消される。この場合
に、塩基度１程度のＣａＯ−８ｉＯ２二元系スラグを用
いると、アルミナを吸収して更にスラグの融点が低下す
るので、新たな熱源を必要とすることなく、スラグは固
化しない。溶鋼中アルミナの飽和状態が解消することに
より、溶鋼の［０］量が更に低下し、鋳造溶鋼の介在物
量が減少する。In the method for refining molten steel according to the present invention, slag is added to the molten steel after tapping to actively transfer alumina from the molten steel to the slag. The added slag is sufficiently melted simply by placing it on top of the molten steel. A part of the alumina is absorbed into the molten slag, and the saturated state of alumina is eliminated. In this case, when a CaO-8iO2 binary slag with a basicity of about 1 is used, the melting point of the slag is further lowered by absorbing alumina, so a new heat source is not required and the slag does not solidify. By eliminating the saturated state of alumina in the molten steel, the [0] amount of the molten steel further decreases, and the amount of inclusions in the cast molten steel decreases.
［実施例］
以下、添付の図面を参照して、この発明の実施例につい
て具体的に説明する。[Embodiments] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
この実施例では、低窒素鋼を溶製する場合について説明
する。In this example, a case will be described in which low nitrogen steel is produced.
吹錬終了後に、転炉を傾動させ、溶鋼を鍋に出鋼する。After blowing, the converter is tilted and the molten steel is poured into a ladle.
このとき、溶鋼の窒素ピックアップを防止するために、
脱酸剤を添加することなく、未脱酸状態で出鋼する（工
程１）。なお、出鋼溶鋼の［０］量は約６００ ｐｐｍ
である。At this time, to prevent nitrogen pickup from molten steel,
Steel is tapped in an undeoxidized state without adding a deoxidizing agent (step 1). In addition, the [0] amount of tapped molten steel is approximately 600 ppm
It is.
次いで、鍋内に溶鋼と共に流出した転炉スラグを除去す
る。転炉スラグが鍋内に存在すると、溶鋼が再度酸化さ
れる原因となるため、転炉スラグを早急に除去する必要
がある（工程２）。Next, the converter slag that has flowed into the pot together with the molten steel is removed. If converter slag exists in the ladle, it will cause the molten steel to be oxidized again, so it is necessary to remove the converter slag as soon as possible (Step 2).
転炉スラグ除去後に、塩基度１のＣａＯ−５ｉＯ２二元
系スラグを鍋内に所定量添加し、溶鋼をスラグで覆う。After removing the converter slag, a predetermined amount of CaO-5iO2 binary slag with a basicity of 1 is added into the pot, and the molten steel is covered with the slag.
この場合に、スラグの添加量は、溶鋼１トン当りに対し
て約２．５ｋｇとすることが好ましく、例えば、出鋼溶
鋼が３２０トンである場合には約８００ ｋｇのスラグ
を添加する（工程３）。In this case, the amount of slag added is preferably about 2.5 kg per ton of molten steel. For example, when the amount of molten steel tapped is 320 tons, about 800 kg of slag is added (process 3).
添加スラグは、上置き状態で溶鋼の保有熱により溶融滓
化する。スラグは、その成分範囲がＣａＯおよびＳｉＯ
□を５０±５重量％に調整してあり、この組成では融点
が約１４５０℃である。The added slag is turned into molten slag by the retained heat of the molten steel when placed on top. Slag has a composition range of CaO and SiO
□ is adjusted to 50±5% by weight, and this composition has a melting point of about 1450°C.
次に、鍋をＲＨ脱ガス設備に搬送し、鍋内の溶鋼を脱ガ
ス槽に吸い上げて脱ガス処理する。この脱ガス処理中に
、溶鋼に所定量の金属アルミニウムを添加し、溶鋼を脱
酸する。アルミニウムが溶鋼中［０］と反応してアルミ
ナが生じ、［０］ 瓜が初期の６００ ｐｐｍから２０
ｐｐｍに低下する。このアルミナは、槽内のスラグに
移行・吸収されると共に、その一部が鍋内に流出して上
記の添加スラグに移行・吸収される（工程４）。Next, the ladle is transported to an RH degassing facility, and the molten steel in the ladle is sucked up into a degassing tank for degassing treatment. During this degassing treatment, a predetermined amount of metallic aluminum is added to the molten steel to deoxidize the molten steel. Aluminum reacts with [0] in the molten steel to produce alumina, and the [0] melon becomes 20 ppm from the initial 600 ppm.
ppm. This alumina is transferred to and absorbed by the slag in the tank, and a part of it flows into the pot and transferred to and absorbed by the added slag (Step 4).
鍋内のスラグは、アルミナの移行によりＣａＯ−３ｔ
０２−ＡＮ ２０３の三元系組成となって、その融点が
更に低下するので、固化することがない。The slag in the pot becomes CaO-3t due to alumina migration.
It becomes a ternary composition of 02-AN 203 and its melting point is further lowered, so it does not solidify.
この脱ガス処理工程において、溶鋼中［Ｎ］が３’ ５
ｐｐｍ・以下に低減され、低窒素鋼に適した溶鋼とす
ることができる。In this degassing process, [N] in the molten steel is 3' 5
It can be reduced to less than ppm, and can be made into molten steel suitable for low nitrogen steel.
脱ガス処理後、鍋を連続鋳造設備に搬送し、鍋内の溶鋼
をタンデイツシュを介して鋳型に連続鋳造する（工程５
）。After the degassing treatment, the ladle is transported to continuous casting equipment, and the molten steel in the ladle is continuously cast into a mold via a tundish (step 5).
).
上記実施例によれば、脱ガス・脱酸処理工程４から鋳造
工程５に至るまで、溶鋼を特殊スラグで覆っているので
、脱酸処理により生じたアルミナをスラグで有効に除去
することができる。この結果、鋳造溶鋼の［０コ量を約
１５ｐｐｍ以下に低減することができ、鋳片表面疵の発
生率を大幅に低減することができた。例えば、表面処理
鋼板の表面欠陥率を、従来の３０％から１０％未満に低
減することができた。According to the above embodiment, since the molten steel is covered with special slag from the degassing/deoxidizing treatment step 4 to the casting step 5, alumina produced by the deoxidizing treatment can be effectively removed with the slag. . As a result, the amount of [0] in the cast molten steel could be reduced to about 15 ppm or less, and the incidence of surface defects on the slab could be significantly reduced. For example, the surface defect rate of surface-treated steel sheets could be reduced from the conventional 30% to less than 10%.
更に、溶鋼の［０］量を低減し、アルミナの存在量が飽
和状態まで余裕があるので、脱酸剤の添加量の変動によ
りアルミナ生成量が変動しても、アルミナのばらつきに
よる吸収能変化が少ないという効果がある。Furthermore, since the [0] amount of molten steel is reduced and there is enough room for the amount of alumina present to reach saturation, even if the amount of alumina produced changes due to changes in the amount of deoxidizer added, the absorption capacity will not change due to variations in alumina. This has the effect of reducing
なお、上記実施例では、脱ガス処理工程で溶鋼を脱酸す
る場合について説明したが、ＬＦ処理等の他の二次精錬
のとき又は転炉出鋼のときに脱酸する場合にも適用する
ことができる。In addition, in the above example, the case where molten steel is deoxidized in the degassing treatment process is described, but it is also applicable to the case where deoxidation is performed during other secondary refining such as LF treatment or when steel is tapped from a converter. be able to.
また、上記実施例では、添加スラグとして塩基度１の二
元系スラグを用いたが、これに限られることなく、溶鋼
に上置きするだけで溶融滓化する組成であれば他の成分
系のスラグを採用することも可能である。In addition, in the above example, a binary slag with a basicity of 1 was used as the additive slag, but it is not limited to this, and other component systems may be used as long as the composition turns into molten slag just by placing it on top of the molten steel. It is also possible to use slag.
また、上記実施例では、精錬した溶鋼を連続鋳造する場
合について説明したが、これに限られることなく、鋳塊
を製造する場合にも同様の効果を得ることができる。Further, in the above embodiments, the case where refined molten steel is continuously cast has been described, but the present invention is not limited to this, and similar effects can be obtained when producing an ingot.
［発明の効果］
本発明によれば、転炉出鋼後の脱酸処理生成物を除去し
、鋳造溶鋼の介在物を低減することができる。このため
、鋳片表面疵等の発生を防止することができ、清浄な組
織を有する製品を得ることができる。[Effects of the Invention] According to the present invention, it is possible to remove deoxidation treatment products after steel tapping from a converter and reduce inclusions in cast molten steel. Therefore, it is possible to prevent the occurrence of surface defects, etc. of the slab, and it is possible to obtain a product having a clean structure.
第１図は本発明の実施例に係る溶鋼の精錬方法を説明す
るための工程図である。FIG. 1 is a process diagram for explaining a method for refining molten steel according to an embodiment of the present invention.
Claims (1)
転炉出鋼された溶鋼に添加することを特徴とする溶鋼の
精錬方法。Slag containing components that can react with deoxidation products in molten steel,
A method for refining molten steel characterized by adding it to molten steel tapped in a converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1144956A JPH0310015A (en) | 1989-06-07 | 1989-06-07 | Method for refining molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1144956A JPH0310015A (en) | 1989-06-07 | 1989-06-07 | Method for refining molten steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0310015A true JPH0310015A (en) | 1991-01-17 |
Family
ID=15374105
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1144956A Pending JPH0310015A (en) | 1989-06-07 | 1989-06-07 | Method for refining molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0310015A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020111773A (en) * | 2019-01-10 | 2020-07-27 | 日本製鉄株式会社 | MELTING METHOD OF HIGH Al-CONTAINING STEEL |
-
1989
- 1989-06-07 JP JP1144956A patent/JPH0310015A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020111773A (en) * | 2019-01-10 | 2020-07-27 | 日本製鉄株式会社 | MELTING METHOD OF HIGH Al-CONTAINING STEEL |
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