JPS6345901B2 - - Google Patents
Info
- Publication number
- JPS6345901B2 JPS6345901B2 JP55071011A JP7101180A JPS6345901B2 JP S6345901 B2 JPS6345901 B2 JP S6345901B2 JP 55071011 A JP55071011 A JP 55071011A JP 7101180 A JP7101180 A JP 7101180A JP S6345901 B2 JPS6345901 B2 JP S6345901B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- molten steel
- tundish
- ladle
- continuous casting
- 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
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 55
- 239000010959 steel Substances 0.000 claims description 55
- 238000009749 continuous casting Methods 0.000 claims description 19
- 238000009849 vacuum degassing Methods 0.000 claims description 17
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims 1
- 238000000034 method Methods 0.000 description 30
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 13
- 229910052760 oxygen Inorganic materials 0.000 description 13
- 239000001301 oxygen Substances 0.000 description 13
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 5
- 238000007872 degassing Methods 0.000 description 5
- 238000007654 immersion Methods 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000002893 slag Substances 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- 238000007792 addition Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 229910001327 Rimmed steel Inorganic materials 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910001336 Semi-killed steel Inorganic materials 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/113—Treating the molten metal by vacuum treating
Description
【発明の詳細な説明】
本発明はブローホールおよび非金属介在物の少
ない連鋳スラブの製造法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a continuously cast slab with fewer blowholes and nonmetallic inclusions.
鋼の連続鋳造法は、造塊−分塊法に比べて歩留
が良く工程も省略できるので近年の鋼製造工程の
主流となりつつあり、その製造可能範囲も拡大し
てきた。 Continuous casting of steel has a higher yield than the ingot-blowing method and can omit steps, so it has become the mainstream of steel manufacturing processes in recent years, and the range of possible manufacturing has expanded.
一方、製鋼工程における脱酸型式には、未脱酸
方式（リムド鋼）、弱脱酸方式（セミキルド鋼）
および強脱酸方式（キルド鋼）の３型式があり、
弱および強脱酸方式では、製鋼炉からの出鋼中も
しくは真空脱ガス処理中に、Al、Siその他の脱
酸剤を添加して溶鋼中の溶存酸素を除去する。こ
の脱酸型式の相異による得失は、大略次のようで
ある。すなわち、未脱酸鋼は、Al、Si等の添加
がないので原価面で有利であるだけでなく造塊法
で製造する場合は表面品質も優れているが、その
反面内部の均質性に問題がある。これに対して強
脱酸方式は、内部の均質性は改善されるものの原
価の不利と非金属介在物の問題が不可避である。
弱脱酸方式は両者の中間的存在といえる。 On the other hand, deoxidizing methods in the steelmaking process include non-deoxidizing method (rimmed steel) and weak deoxidizing method (semi-killed steel).
There are three types: and strong deoxidation method (killed steel).
In the weak and strong deoxidizing methods, dissolved oxygen in molten steel is removed by adding deoxidizing agents such as Al, Si, etc. during tapping from a steelmaking furnace or during vacuum degassing treatment. The advantages and disadvantages of this difference in deoxidation types are roughly as follows. In other words, undeoxidized steel is not only advantageous in terms of cost because it does not contain additions of Al, Si, etc., but also has excellent surface quality when manufactured by the ingot method, but on the other hand, it has problems with internal homogeneity. There is. On the other hand, the strong deoxidizing method improves internal homogeneity, but inevitably suffers from disadvantages in cost and the problem of nonmetallic inclusions.
The weak deoxidation method can be said to be an intermediate between the two.
連続鋳造法は造塊法に比べて内部の均質な鋼片
を製造するのに適した方法であるので、未脱酸鋼
の連続鋳造法が可能になれば原価面でも品質面で
も非常な利益を生じる。しかしながら、連続鋳造
法の最近の発展によつて鋼種的には低炭素鋼から
高炭素鋼、合金鋼までの製造が可能になり、材料
面では薄板から厚板、高張力鋼などの製造が可能
となつているにもかかわらず、脱酸型式について
はいまだ未脱酸鋼の連続鋳造化が営業生産的水準
で可能となつていない。 Continuous casting is a method that is more suitable for producing internally homogeneous steel slabs than ingot casting, so if continuous casting of unoxidized steel becomes possible, there will be significant benefits in terms of both cost and quality. occurs. However, recent developments in continuous casting methods have made it possible to manufacture a range of steel types from low carbon steel to high carbon steel and alloy steel, and in terms of materials, it is now possible to manufacture thin plates, thick plates, high-strength steel, etc. Despite this, it has not yet become possible to continuously cast unoxidized steel at a commercially productive level.
連続鋳造法で未脱酸鋼の製造が困難である理由
は、大略次のとおりである。すなわち、未脱酸状
態の溶鋼では凝固に際して溶鋼中の溶存酸素と炭
素が反応してCOガスを生成するが、連続鋳造法
では、凝固殻の生長が速いのでCOガス気泡が凝
固殻表面に捕捉されて鋳片にピンホール状の欠陥
を生じ、圧延工程で製品とするに耐えない線状の
疵となるためである。 The reasons why it is difficult to produce non-deoxidized steel using the continuous casting method are roughly as follows. In other words, in undeoxidized molten steel, dissolved oxygen and carbon in the molten steel react during solidification to produce CO gas, but in continuous casting, the solidified shell grows quickly, so CO gas bubbles are trapped on the surface of the solidified shell. This is because pinhole-like defects occur in the slab, resulting in linear flaws that cannot be used as a product during the rolling process.
このようなことから、連続鋳造に際しては、気
泡発生を防ぐためにキルド化することがこれまで
一般的であり、しかも脱酸コントロールが厳密に
できないために安全側を狂つてSi、Al等の脱酸
剤を過剰に使用してきた。このため、コスト的に
高くなるだけでなく、脱酸生成物が鋳片に捕捉さ
れて起こる製品表面疵の問題、脱酸剤の過剰使用
による材質劣化の問題が顕在化していた。また、
脱酸生成物（主としてAl2O3）により、取鍋、タ
ンデイシユ等の出口のノズル閉塞が起こり、連続
鋳造を困難にすることがあつた。 For this reason, in continuous casting, it has been common practice to perform a killed process to prevent the generation of bubbles, and since deoxidation control cannot be strictly controlled, deoxidation of Si, Al, etc. has been carried out on the side of safety. The drug has been used in excess. For this reason, not only the cost increases, but also the problem of product surface flaws caused by the deoxidation products being trapped in the slab, and the problem of material deterioration due to excessive use of the deoxidizer have become apparent. Also,
Deoxidation products (mainly Al 2 O 3 ) sometimes clog the nozzle at the outlet of a ladle, tundish, etc., making continuous casting difficult.
このため、例えば、米国特許第3412781号明細
書に見られるように冷間圧延用鋼板を連続鋳造に
よつて安定かつ多量に生産することを目的として
鋼成分のバランスを図つた技術が紹介され、ま
た、特公昭47−47209号、特公昭51−4935号公報
等に見られるように鋳造作業の高能率化高速鋳造
化をはかるとともに表面性状を狙つた技術が紹介
された。しかしながらこれらの技術によつて得た
鋼板は汎用性に乏しくかつ製造工程においても
種々の問題を有するものであつた。 For this reason, for example, as seen in U.S. Pat. No. 3,412,781, a technology has been introduced that aims to balance the steel components with the aim of producing stable and large quantities of cold rolling steel sheets by continuous casting. In addition, as seen in Japanese Patent Publication No. 47-47209 and Japanese Patent Publication No. 4935-1987, techniques aimed at improving the efficiency and speed of casting operations and improving surface quality were introduced. However, the steel plates obtained by these techniques lack versatility and have various problems in the manufacturing process.
そこで、本発明者等は各種調査研究を行なつた
結果、上記いずれの技術も脱酸剤としてAlとSi
を併用しているため、鋼中Siの存在により材質的
にリムド鋼より硬く、またこの方法による脱酸型
式においては生成する非金属介在物はAl2O3−
SiO2−MnO系の比較的低融点生成物であり熱延
薄鋼板として使用する場合の加工性は必ずしも満
足できるものではないことを解明した。 Therefore, as a result of various research studies, the present inventors have found that none of the above techniques uses Al and Si as deoxidizing agents.
Due to the presence of Si in the steel, the material is harder than rimmed steel, and in the deoxidation type using this method, the nonmetallic inclusions generated are Al 2 O 3 −
It was found that this is a relatively low melting point product of the SiO 2 -MnO system, and its workability is not necessarily satisfactory when used as hot rolled thin steel sheets.
このようにSi脱酸することによるSi含有量の高
い（Si0.03％）鋼による欠点は、Siが固溶Siま
たはシリケート介在物として直接的または間接的
に影響を及ぼしているものである。ここにSi−
freeによる連続鋳造用弱脱酸鋼が要望される経緯
がある。Si−free鋼としては特開昭50−8713号、
特開昭53−73422号に見られるが、溶製時の脱酸
制御が困難であり、また、連続鋳造時の高速引抜
が必須としている。 The disadvantage of steel with a high Si content (Si 0.03%) due to Si deoxidation in this way is that Si has an effect directly or indirectly as solid solution Si or silicate inclusions. Si- here
There is a history of demand for weakly deoxidized steel for continuous casting using free. As Si-free steel, JP-A No. 50-8713,
As seen in JP-A-53-73422, it is difficult to control deoxidation during melting, and high-speed drawing during continuous casting is essential.
本発明に目的は、このような従来の連続鋳造法
の各種の問題を解決することであり、ブロホール
および非金属介在物の少ない健全な連鋳スラブを
経済的および操業的有利に製造することである。 The purpose of the present invention is to solve various problems of such conventional continuous casting methods, and to produce sound continuous cast slabs with few blowholes and nonmetallic inclusions economically and operationally. be.
この目的において本発明法の連鋳スラブの製造
法は、取鍋に受鋼した炭素量が0.15％以下の未脱
酸溶鋼をこの取鍋内で真空脱ガス処理すると共に
Alによる脱酸を行ない、得られた弱脱酸溶鋼を
連続鋳造機のタンデイシユに注入し、このタンデ
イシユ内の溶鋼を再度真空脱ガス処理してから鋳
型に注入することを特徴とする。 For this purpose, the continuous casting slab manufacturing method of the present invention involves vacuum degassing treatment of undeoxidized molten steel with a carbon content of 0.15% or less received in a ladle, and
The method is characterized in that the weakly deoxidized molten steel obtained by deoxidizing with Al is poured into a tundish of a continuous casting machine, and the molten steel in this tundish is subjected to vacuum degassing treatment again before being poured into a mold.
本発明法の実施にあたり、取鍋内の真空脱ガス
処理は取鍋全体を真空容器中にセツトする取鍋真
空脱ガス装置、あるいは取鍋内溶鋼を真空室に還
流させるRHまたはDH装置などの公知の装置を
用いて行なうことができる。また、タンデイシユ
内の溶鋼の真空脱ガス処理は例えば特公昭53−
4483号公報に記載された連続真空脱ガス装置を用
いて好適に実施し得る。 In implementing the method of the present invention, the vacuum degassing treatment inside the ladle can be carried out using a ladle vacuum degassing device in which the entire ladle is set in a vacuum container, or an RH or DH device in which the molten steel in the ladle is returned to a vacuum chamber. This can be carried out using a known device. In addition, the vacuum degassing treatment of molten steel in the tundish is, for example,
This can be suitably carried out using the continuous vacuum degassing apparatus described in Japanese Patent No. 4483.
第１図は本発明法の実施に好適に使用すること
ができる装置を示すもので、取鍋脱ガス後のタン
デイシユ脱ガス工程の例を示している。第１図に
おいて、１は連鋳用鋳型、２はこの鋳型１に流す
溶鋼を保持するためのタンデイシユ、３はこのタ
ンデイシユ２に溶鋼を注入する取鍋であり、タン
デイシユ２には溶鋼を真空処理するための真空容
器４を備えている。この真空容器４は、頂部に排
気孔５、底部に吸込管６および吐出管７を有し、
排気孔５は排気装置（図示しない）に連結され
る。吸込管６は吐出管７よりも若干短く、吐出管
７の端部がタンデイシユノズル８に連結するよう
にこの真空容器４をタンデイシユ２内にセツト
し、この状態で吸込管６の端部はタンデイシユ２
の底よりも上方に位置する関係になつている。し
たがつて、排気装置の駆動によつて容器内が減圧
されると、タンデイシユ２内の溶鋼は吸込管６よ
り容器内に吸上げられ、吐出管７からタンデイシ
ユノズル８に吐出される。タンデイシユノズル８
には浸漬ノズル９が取付けてあり、鋳型１内に滞
留する溶鋼内に浸漬されたこの浸漬ノズル９を経
て溶鋼は鋳型１に連続供給される。このようにし
て、タンデイシユ内溶鋼が鋳型１に注入される前
に連続真空脱ガス処理されるが、これだけでは本
発明の目的は十分に達成できない。このタンデイ
シユ２に注入された溶鋼自体も溶存酸素を所定値
以下にまで低下させておく必要がある。このた
め、取鍋３の溶鋼１０も真空脱ガス処理されると
共にAl脱酸された弱脱酸鋼を使用し、この取鍋
３からタンデイシユ２への注入もシール用ノズル
１１を使用し、また鋳型１には人工の溶融スラグ
層１２を形成させておく。 FIG. 1 shows an apparatus that can be suitably used for carrying out the method of the present invention, and shows an example of a tundish degassing step after ladle degassing. In Fig. 1, 1 is a mold for continuous casting, 2 is a tundish for holding the molten steel poured into the tundish 1, 3 is a ladle for pouring the molten steel into the tundish 2, and the tundish 2 is used to vacuum-process the molten steel. It is equipped with a vacuum container 4 for This vacuum container 4 has an exhaust hole 5 at the top, a suction pipe 6 and a discharge pipe 7 at the bottom,
The exhaust hole 5 is connected to an exhaust device (not shown). The suction pipe 6 is slightly shorter than the discharge pipe 7, and the vacuum container 4 is set in the tundish 2 so that the end of the discharge pipe 7 is connected to the tundish nozzle 8. is tendishyu 2
The relationship is such that it is located above the bottom of the . Therefore, when the pressure inside the container is reduced by driving the exhaust device, the molten steel in the tundish 2 is drawn up into the container through the suction pipe 6 and is discharged from the discharge pipe 7 to the tundish nozzle 8. Tundish nozzle 8
An immersion nozzle 9 is attached to the immersion nozzle 9, and molten steel is continuously supplied to the mold 1 through the immersion nozzle 9, which is immersed in the molten steel remaining in the mold 1. In this way, the molten steel in the tundish is subjected to continuous vacuum degassing treatment before being poured into the mold 1, but this alone cannot sufficiently achieve the object of the present invention. The dissolved oxygen of the molten steel itself injected into the tundish 2 must be reduced to a predetermined value or less. For this reason, the molten steel 10 in the ladle 3 is also vacuum degassed and Al-deoxidized weakly deoxidized steel, and the injection from the ladle 3 into the tundish 2 is also performed using the sealing nozzle 11. An artificial molten slag layer 12 is formed in the mold 1.
以下に本発明法の好ましい実施の態様を説明す
る。 Preferred embodiments of the method of the present invention will be described below.
転炉工程で、炭素含有量が0.15％以下の溶鋼、
例えばＣ＝0.10％の炭素含有量の溶鋼を溶製する
と、溶存酸素は300〜500ppm程度である。これを
取鍋に出鋼し、この出鋼中に鋼の調質を目的とし
てMn源を添加する。これにより取鍋内受鋼は
200〜300ppmまで溶存酸素が低下するが、この
Mn添加はAlやSiなどのように脱酸を目的とする
のではなく、取鍋内には未脱酸状態の溶鋼が収容
される。次いで、この取鍋を真空容器内にセツト
して真空脱ガス処理し、Ｃ＋Ｏ＝COの反応を進
行させると同時にAl添加による脱酸を行ない鋼
中炭素0.08％以下、溶存酸素100ppm以下にまで
低下させる。この鋼中炭素と酸素は必ずしも化学
量論的に減少しない。これは転炉スラグまたは出
鋼中での大気中からの酸素の供給が不可避である
からである。この取鍋脱ガス処理を終えた溶鋼は
次に第１図に示すようにタンデイシユに注入し、
鋳型１への注入前に連続真空処理され、再度Ｃ＋
Ｏ＝COの反応によつて、Ｃ＝0.05％程度、０＜
50ppmまで脱炭脱酸される。この溶存酸素が
50ppm以下にまで脱酸された溶鋼は浸漬ノズルお
よび人工スラグによつて大気と遮断された状態で
鋳型に注入でき、鋳型内では凝固にさいしても
COガスの発生は軽微となつてブローホール疵の
ない健全な連鋳スラブが得られる。 In the converter process, molten steel with a carbon content of 0.15% or less,
For example, when molten steel with a carbon content of C=0.10% is produced, dissolved oxygen is about 300 to 500 ppm. This steel is tapped into a ladle, and a Mn source is added during this tapping for the purpose of refining the steel. As a result, the receiving steel inside the ladle is
Dissolved oxygen decreases to 200 to 300 ppm, but this
Mn is not added for the purpose of deoxidizing like Al or Si, but the ladle contains molten steel in an undeoxidized state. Next, this ladle is placed in a vacuum container and subjected to vacuum degassing treatment to advance the C+O=CO reaction and at the same time deoxidize by adding Al, reducing the carbon in the steel to 0.08% or less and dissolved oxygen to 100ppm or less. let Carbon and oxygen in the steel do not necessarily decrease stoichiometrically. This is because oxygen must be supplied from the atmosphere in the converter slag or tapped steel. The molten steel that has been degassed in the ladle is then poured into a tundish as shown in Figure 1.
Continuous vacuum treatment and C+ again before pouring into mold 1
Due to the reaction of O=CO, C=about 0.05%, 0<
Decarboxylated and deoxidized to 50ppm. This dissolved oxygen
Molten steel that has been deoxidized to 50 ppm or less can be injected into the mold while being isolated from the atmosphere using an immersion nozzle and artificial slag, and even during solidification inside the mold,
The generation of CO gas is minimal, and a sound continuously cast slab without blowhole defects can be obtained.
本発明法は前記のように取鍋に受鋼した未脱酸
溶鋼をSi脱酸剤の添加なしで、取鍋内とタンデイ
シユ内の２段階からなる真空脱ガス処理によつて
鋼中炭素と酸素との反応により脱酸を行なうこと
を特徴とするものである。この２段階からなる真
空脱ガス処理に代えて、いづれか１方のみの１段
階でこれを実施することは、特別な操業または鋼
種を除いて、実操業上面で有利とはならない。例
えば、取鍋内脱ガス処理のみ（Alの添加を含む）
によつて減圧下におけるCO平衡値の10ppm程度
まで酸素を除去してこれを鋳造しようとしても、
この真空処理剤溶鋼の取鍋移送中や鋳造期間中に
取鍋内またはタンデイシユ内において大気圧下の
平衡状態に長時間保持されるから、この間に溶鋼
中の酸素が増加して、鋳片表面にピンホールが発
生する条件となることが避けられない。また、タ
ンデイシユ内での真空脱ガス処理のみによつて
は、その真空脱ガス装置の形状並びに処理量に自
づと限界があり、鋳型以降の溶鋼処理量１〜
8T／分の如き通常の鋳造条件に対して、反応速
度論的に十分な脱ガス能力を有するような大型装
置を設計することが実際上困難である。例えば転
炉で溶製された溶鋼は炭素含有量が低くなるにつ
れて溶存酸素量は増加する傾向があるが、特に炭
素含有量が0.15％以下にまで脱炭された転炉溶製
鋼に対しては、タンデイシユ内での真空脱ガス処
理だけで十分な脱ガスを行なうことは実質上困難
である。 The method of the present invention removes carbon from the undeoxidized molten steel received in the ladle as described above by performing a two-step vacuum degassing treatment in the ladle and in the tundish without adding any Si deoxidizing agent. It is characterized by deoxidizing by reaction with oxygen. Instead of this two-stage vacuum degassing treatment, it is not advantageous in terms of actual operation to carry out only one of the two stages in one stage, except for special operations or steel types. For example, only in-ladle degassing treatment (including addition of Al)
Even if you try to remove oxygen to about 10 ppm of the CO equilibrium value under reduced pressure and cast it,
During the transfer of the vacuum treatment agent to the ladle and during the casting period, the ladle or tundish is maintained in an equilibrium state under atmospheric pressure for a long period of time, and during this time the oxygen in the molten steel increases and the surface of the slab It is unavoidable that this will become a condition for pinholes to occur. In addition, depending on the vacuum degassing treatment only in the tundish, there are limits to the shape of the vacuum degassing equipment and the throughput, and the throughput of molten steel after the mold is 1 to 1.
It is practically difficult to design a large-scale device that has sufficient degassing ability in terms of reaction kinetics for normal casting conditions such as 8 T/min. For example, in molten steel made in a converter, the amount of dissolved oxygen tends to increase as the carbon content decreases, but especially for molten steel made in a converter whose carbon content has been decarburized to 0.15% or less. However, it is practically difficult to perform sufficient degassing only by vacuum degassing treatment within the tundish.
本発明にあつては、取鍋内溶鋼の真空脱ガス処
理に加えてタンデイシユ内溶鋼の真空脱ガス処理
を併用することによつて、従来の連続鋳造法の大
きな課題であつた弱脱酸鋼の連続鋳造を実現した
ものであり、Si脱酸剤添加に基づくSiO2−Al2O3
−MnO系介在物の熱間加工性に及ぼす悪影響な
どを未然に回避しながら、リミングアクシヨンに
よるブローホールの発生を防止して健全な連鋳ス
ラブを経済的かつ操業的に有利に製造可能とした
ものである。そして、本発明によると、従来の弱
脱酸鋼の連続鋳造にあつてはピンホール発生防止
対策として必須とされている高速引抜きは必ずし
も必要としない。 In the present invention, by using vacuum degassing treatment of molten steel in a tundish in addition to vacuum degassing treatment of molten steel in a ladle, it is possible to produce weakly deoxidized steel, which was a major problem in conventional continuous casting methods. This technology realized continuous casting of SiO 2 −Al 2 O 3 based on the addition of Si deoxidizer.
-While avoiding the negative effects of MnO-based inclusions on hot workability, it is now possible to economically and operationally advantageously produce sound continuous cast slabs by preventing the occurrence of blowholes due to rimming actions. This is what I did. According to the present invention, high-speed drawing, which is essential as a measure to prevent the occurrence of pinholes in conventional continuous casting of weakly deoxidized steel, is not necessarily required.
第２図に既述の実施態様に従つて製造した本発
明法のスラブの断面写真を示す。この写真に見ら
れるように本発明法によると弱脱酸溶鋼からブロ
ーホールが低減した連鋳片が得られる。第３図の
写真は弱脱酸溶鋼の従来法によるスラブの断面写
真であり、従来法ではこの第３図の写真に見られ
る程度のブローホールが存在したのが普通であつ
た。 FIG. 2 shows a cross-sectional photograph of a slab manufactured by the method of the present invention according to the embodiment described above. As seen in this photograph, according to the method of the present invention, continuous cast pieces with fewer blowholes can be obtained from weakly deoxidized molten steel. The photograph in FIG. 3 is a cross-sectional photograph of a slab obtained by the conventional method of mildly deoxidized molten steel, and in the conventional method, blowholes as seen in the photograph in FIG. 3 were usually present.
第１図は本発明法の実施に使用する装置の要部
断面図、第２図は本発明法によつて得られた連鋳
スラブの狭断面の金属組織を示すマクロエツチ真
真、第３図は従来法の未脱酸溶鋼の連鋳スラブの
狭断面の金属組織を示すマクロエツチ写真であ
る。
１……鋳型、２……タンデイシユ、３……取
鍋、４……真空容器、９……浸漬ノズル、１１…
…シール用ノズル、１２……人工スラグ。
Fig. 1 is a cross-sectional view of the main part of the equipment used to carry out the method of the present invention, Fig. 2 is a macro etch diagram showing the metal structure of a narrow cross section of a continuously cast slab obtained by the method of the present invention, and Fig. 3 is a macroetch photograph showing the metal structure of a narrow cross section of a continuous cast slab of undeoxidized molten steel produced by the conventional method. 1...Mold, 2...Tendishi, 3...Ladle, 4...Vacuum container, 9...Immersion nozzle, 11...
...Sealing nozzle, 12...Artificial slag.
Claims (1)
溶鋼をこの取鍋内で真空脱ガス処理すると共に
Alによる脱酸を行ない、得られた弱脱酸溶鋼を
連続鋳造機のタンデイシユに注入し、このタンデ
イシユ内の溶鋼を再度真空脱ガス処理してから鋳
型に注入することからなるブローホールおよび非
金属介在物の少ない連鋳スラブの製造法。1. Undeoxidized molten steel with a carbon content of 0.15% or less received in a ladle is vacuum degassed in this ladle, and
Blowholes and non-metallic metals are created by deoxidizing with Al, injecting the resulting weakly deoxidized molten steel into the tundish of a continuous casting machine, and then vacuum-degassing the molten steel in the tundish again before injecting it into the mold. A method for producing continuously cast slabs with fewer inclusions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7101180A JPS56168941A (en) | 1980-05-28 | 1980-05-28 | Manufacture of continuous casting slab with few blowholes and little nonmetallic inclusion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7101180A JPS56168941A (en) | 1980-05-28 | 1980-05-28 | Manufacture of continuous casting slab with few blowholes and little nonmetallic inclusion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56168941A JPS56168941A (en) | 1981-12-25 |
| JPS6345901B2 true JPS6345901B2 (en) | 1988-09-12 |
Family
ID=13448125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7101180A Granted JPS56168941A (en) | 1980-05-28 | 1980-05-28 | Manufacture of continuous casting slab with few blowholes and little nonmetallic inclusion |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56168941A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0332309U (en) * | 1989-08-03 | 1991-03-28 | ||
| JPH0525122Y2 (en) * | 1988-09-30 | 1993-06-25 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101047579B1 (en) | 2008-12-30 | 2011-07-07 | 주식회사 포스코 | Tapping device and tapping method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4956830A (en) * | 1972-10-05 | 1974-06-03 | ||
| JPS5497520A (en) * | 1978-01-19 | 1979-08-01 | Sumitomo Metal Ind Ltd | Production of steel to be enameled |
-
1980
- 1980-05-28 JP JP7101180A patent/JPS56168941A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4956830A (en) * | 1972-10-05 | 1974-06-03 | ||
| JPS5497520A (en) * | 1978-01-19 | 1979-08-01 | Sumitomo Metal Ind Ltd | Production of steel to be enameled |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0525122Y2 (en) * | 1988-09-30 | 1993-06-25 | ||
| JPH0332309U (en) * | 1989-08-03 | 1991-03-28 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56168941A (en) | 1981-12-25 |
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