JPH067907A - Production of continuously cast slab excellent in surface characteristic - Google Patents

Production of continuously cast slab excellent in surface characteristic

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Publication number
JPH067907A
JPH067907A JP16911592A JP16911592A JPH067907A JP H067907 A JPH067907 A JP H067907A JP 16911592 A JP16911592 A JP 16911592A JP 16911592 A JP16911592 A JP 16911592A JP H067907 A JPH067907 A JP H067907A
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Japan
Prior art keywords
mold
powder
molten
casting
molten steel
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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
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JP16911592A
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Japanese (ja)
Inventor
Nagayasu Bessho
Hiroshi Sekiguchi
Seiji Taguchi
Hisao Yamazaki
永康 別所
久生 山崎
整司 田口
浩 関口
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Kawasaki Steel Corp
川崎製鉄株式会社
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Application filed by Kawasaki Steel Corp, 川崎製鉄株式会社 filed Critical Kawasaki Steel Corp
Priority to JP16911592A priority Critical patent/JPH067907A/en
Publication of JPH067907A publication Critical patent/JPH067907A/en
Application status is Pending legal-status Critical

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Abstract

PURPOSE:To improve the surface characteristic of a cast slab in an unsteady condition at the time of starting a casting. CONSTITUTION:At the time of pouring a molten steel 8 into a mold 4 from a tundish 7, mold powder 1 added into the mold 4 is beforehand melted by using a melting furnace 2. After adding the molten mold powder 1 into the mold 4 simultaneously with the of start of the casting, electrodes 3 are dipped in the molten layer and energized, and the lowering of temp. is prevented by Joule heat generated in the powder layer, and the molten thickness of the powder is secured. Therefore, since the powder layer melted at the starting time is secured, the surface characteristic of the cast slab can be improved.

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【産業上の利用分野】本発明は、鋼の連鋳鋳片の製造方法に係り、詳しくは鋳込みスタートの非定常部において表面性状の優れた連鋳鋳片を製造する方法に関するものである。 The present invention relates relates to a method for producing a continuous casting slab of steel, to a method of details producing excellent continuous casting slab surface texture in the non-stationary part of the casting start.

【0002】 [0002]

【従来の技術】鋼の連続鋳造においては、鋳型内溶鋼の再酸化防止、溶鋼中の介在物の吸着、鋳型と鋳片の潤滑および溶鋼表面の温度低下防止を目的にCaO 、SiO 2などの酸化物から構成するモールドパウダを使用することが一般的である。 In continuous casting of the Related Art Steel, reoxidation prevention of the molten steel in the mold, the inclusions in the molten steel adsorption, for the purpose of temperature drop preventing lubrication and the molten steel surface of the mold and the slab CaO, such as SiO 2 it is common to use a mold powder which constitutes from oxides. 連鋳のスタート時に相当する鋳片は、モールドパウダの溶融が不安定であり、鋳造する溶鋼の温度低下が生じたり、鋳造速度が変動して非定常状態にあるため、のろかみ欠陥を生じたり、自動車用外板などに適用される極低炭素鋼ではカーボンを数パーセント含有する未溶融パウダと溶鋼の接触により溶鋼が加炭する現象を誘発させる。 Corresponds to the start of the continuous casting slab, melting of mold powder is unstable, or the temperature drop of molten steel caused to casting, since the casting speed is varied in a non-steady state, generate NoroKami defects or, in the ultra-low carbon steel is applied to such automotive outer panels to induce the phenomenon of molten steel to carburization by contact unmelted powder and the molten steel to a few percent containing carbon.

【0003】以上のような問題点を防止する従来技術としては、特開平1-202439号公報、特開昭63-230259 号公報、特開昭61-086055 号公報などに示すように、連鋳の非定常時に予め溶融したモールドパウダを鋳型内に添加し、モールドパウダに起因する欠陥を防止する方法がある。 The Conventionally prevent the problems described above technique, JP-A-1-202439, JP-Sho 63-230259 discloses, as shown in such JP 61-086055, continuous casting the pre-melted mold powder at unsteady added to the mold, there is a method of preventing defects due to mold powder of. この方法では、鋳型内に添加されたパウダが溶融状態であるため、パウダ表面からの抜熱が大きく、パウダ表面が固化する現象が生じ、逆に溶鋼メニスカス温度の低下を引き起こす問題が生じる。 In this method, was added to the mold powder is in a molten state, a large heat removal from the powder surface, a phenomenon occurs in which the powder surface solidified, the problem of causing a decrease in the molten steel meniscus temperature conversely occurs.

【0004】 [0004]

【発明が解決するための手段】本発明は、鋳造スタート時に発生するモールドパウダの溶融厚不足によって生じる鋳片の割れや未溶融パウダからの加炭等の問題点を解消すことを目的としたものである。 The present invention is to Means for Solving] was aimed to solve the problems of carburization and the like from cracking and unmelted powder of slab caused by insufficient melting thickness of mold powder which occurs during casting start it is intended.

【0005】 [0005]

【課題を解決するための手段】本発明は、連鋳スタート時に予め溶融させたモールドパウダを連鋳鋳型内に添加することで早期にモールドパウダの溶融層を形成を図り、その後その溶融モールドパウダの輻射による温度低下を防止するために、そのモールドパウダ溶融層に一対以上の電極を浸漬し、抵抗加熱することでパウダ表面からの抜熱を防止し、表面品質の優れた鋳片の製造を提供するものである。 The present invention SUMMARY OF THE INVENTION may, achieving early form molten layer of mold powder into the mold powder obtained by previously melting by adding the continuous casting in the mold during continuous casting start, then the molten mold powder in order to prevent a temperature drop due to radiation, immersed one or more pairs of electrodes in the mold powder melting layer, the heat extraction from it in powder surface to resist heat and prevent the surface quality superior production of the slab it is intended to provide.

【0006】 [0006]

【作用】溶鋼の連続鋳造における鋳込みスタート時は、 [Action] at the start casting in the continuous casting of molten steel,
転炉、二次精錬を経て連鋳工場に運ばれた取鍋内の溶鋼が、バーナ等で予熱した空のタンディッシュに注がれ、 Converter, molten steel in the ladle, which was taken to the continuous casting plant through the secondary refining, poured into the empty tundish which had been preheated by a burner or the like,
タンディッシュ内の溶鋼レベルがある一定高さになった時点で耐火物性のノズルを介して鋳型内に注入される。 When it becomes constant height is molten steel level in the tundish through the nozzle of refractory properties is injected into the mold.
その時の鋳込みは、鋳込み開始時のブレークアウトを回避するため数分間は低速で鋳造し、その後目標の鋳造速度まで増速される。 Then casting of a few minutes to avoid casting start breakout of cast at a low speed, and subsequently increased to the target casting speed of speed.

【0007】従って、鋳造スタート時には、鋳造の定常状態に較べ溶鋼温度の低下、増速(注湯量の増加)のために湯面が不安定となる。 [0007] Therefore, at the time of casting start, molten metal surface becomes unstable due to the decrease of the molten steel temperature compared to the steady state of casting, the speed increase (Note increase of hot water). 鋳造の開始とともに鋳型内に添加されるモールドパウダは、鋳型内の溶鋼温度が低いため溶融しにくくなり、その結果溶融層厚の低下を促し、割れ感受性の高い鋼種では鋳片表面に割れを生じ、 Mold powder to be added into the mold at the start of casting, the molten steel temperature in the mold is less likely to melt because of low, prompting the resulting melt layer reduction in thickness, cracked the slab surface by high grades of crack susceptibility ,
極低炭素鋼では未溶融モールドパウダと溶鋼の接触頻度が増すため未溶融パウダ中の炭素が溶鋼に入り込む、いわいる浸炭が生じるばかりでなく凝固シェルと鋳型間へのモールドパウダ流入が不足しブレークアウトを誘発する場合もある。 In ultra low carbon steel entering the carbon molten steel in the unmelted powder for contact frequency unmelted mold powder and the molten steel is increased, break insufficient mold powder inflow into between the solidified shell and the mold as well Iwairu carburization occurs in some cases to induce out.

【0008】これらの問題を解決するためには、モールドパウダの溶融厚みを十分に確保することが必要であり、本発明は、それら問題点を解消するものである。 [0008] In order to solve these problems, it is necessary to sufficiently ensure the melt thickness of the mold powder, the present invention is to solve these problems. 本発明の特徴は、図1に示すように、タンディッシュ7内の溶鋼8をイマージョンノズル9を介してダミーバー(7)をセットした鋳型(4)内に注入を行う際に、鋳型4に添加するモールドパウダ(1)を予め溶解炉(2)などを用いて溶融し、供給樋(10)を介して鋳込みスタートと同時に添加した後、その溶融層に浸漬した電極(3)に通電し、パウダ層内で発生するジュール熱でパウダの温度低下を防止しパウダの溶融厚みを確保するところにある。 Feature of the present invention, as shown in FIG. 1, when performing injection of the molten steel 8 in the tundish 7 in a mold equipped with a dummy bar (7) via the immersion nozzle 9 (4), added to the mold 4 the mold powder (1) was melted in advance melting furnace (2) by using a for, after the addition at the same time as the start cast through a feed trough (10), and supplying current to the electrodes (3) immersed in the molten layer, certain temperature drop powder by Joule heat generated in powder layer in place to ensure the melt thickness of preventing powder. 鋳造スタート時に十分な溶融厚みが確保できれば、鋳片表面の割れ欠陥を回避でき、溶融させたパウダ中には炭素は含有されていないため浸炭の問題も解消される。 If secured sufficient melt thickness during casting start, can avoid cracking defects of the slab surface, during the melted powder is solved the problem of carburization for not containing carbon.

【0009】前述したように、溶融したモールドパウダ(1)を添加しただけでは大気への輻射により添加直後にパウダ(1)が固化し、モールドパウダ(1)としての目的を果たさないばかりか、ディッケルと呼ばれるようなメニスカス部で溶鋼が異常凝固する現象や、鋳型(4)と凝固シェル(5)間の潤滑不足によりブレークアウトを誘発する結果となる。 [0009] As described above, powder (1) is solidified immediately after the addition only the addition of mold powder (1) was melted by radiation into the atmosphere, not only serves no purpose as mold powder (1), phenomenon and the molten steel is abnormally solidified at the meniscus portion as called deckle, resulting to induce breakout by insufficient lubrication between the mold (4) and the solidified shell (5).

【0010】 [0010]

【実施例】以下、本発明を図1に示す構成の装置を用いた実施例について説明する。 EXAMPLES The following examples will be described using the apparatus having the structure according to the present invention in FIG. 実施例1 0.09〜0.12%C、0.9 〜1.2 %Mn、0.006 〜0.012 % Example 1 0.09~0.12% C, 0.9 ~1.2% Mn, 0.006 ~0.012%
P、0.06〜0.010 %S、0.025 〜0.040 %Alを含有する溶鋼を予め予熱したタンディッシュ内に注入し、その後 P, 0.06~0.010% S, poured into previously preheated Tan the dish molten steel containing 0.025 to 0.040% Al, then
1000〜1500mm幅×220mm 厚の鋳型に注入し鋳造を開始する際、本発明の実施例として、モールドパウダ( 2.9% When starting an injection cast into 1000~1500mm width × 220 mm thick mold, as an embodiment of the present invention, mold powder (2.9%
C、34.4%SiO 2 、33.0%CaO 、 6.1% Al 2 O 3 、13.4%Na C, 34.4% SiO 2, 33.0 % CaO, 6.1% Al 2 O 3, 13.4% Na
2 O、 8.1%F) をシリコニット炉内で溶融させ、鋳型内に添加した直後に100mm φの断面を持つ鉄製の電極を2 2 O, 8.1% F) is melted in siliconit furnace, and the iron electrode having a cross section of 100 mm phi immediately added to the mold 2
本鋳型幅の1/4、3/4位置に浸漬深さが15mmになるように設置し、500 〜700 Aの電流値で通電した。 Immersion depth 1 / 4,3 / 4 position of the mold width is set up such that 15 mm, was supplied at a current of 500 to 700 A. なお、溶融モールドパウダの添加量は鋳型サイズにかかわらず鋳造長5mまでは20〜30mmの溶融厚みを保持するようにした。 The addition amount of the molten mold powder is to cast length 5m regardless mold size was set to hold the molten thickness of 20 to 30 mm.

【0011】本発明の効果を比較例として、同一の鋼種、鋳型サイズで上記のような鋳造スタート時に、本発明と同一成分の粉末パウダを添加した場合(比較例1) [0011] As a comparative example the effect of the present invention, the same steel type, in casting start as described above in a mold size, if the powder powder of the present invention and the same components were added (Comparative Example 1)
と電極を使った加熱なしで、同一成分のモールドパウダを溶融して添加した場合(比較例2)を行った。 And without heating with electrodes was performed when added to melt the mold powder of the same composition (Comparative Example 2). こうして鋳造されたスタート部鋳片の長さ3mに対し表面割れの個数を測定した。 Thus it was determined the number of surface cracks to length 3m of cast start portion cast piece. 結果を表1に示す。 The results are shown in Table 1. 表1に示すように比較例1では、パウダの溶融厚が薄いため割れ個数は In Comparative Example 1 As shown in Table 1, because cracks number molten thickness thin powder is
4.3個/m、また、比較例は添加した溶融パウダが大気への放熱で凝固したため結果的に溶融厚が薄くなったため割れ個数が 4.5個/mであった。 4.3 pieces / m, also, Comparative Examples added molten powder is number cracks because the resulting melt thickness for solidified thinned by heat dissipation to the atmosphere was 4.5 pieces / m. 一方、本発明は鋳型壁と鋳片間に流入するパウダ量が十分で鋳型内での鋳片の均一冷却が可能となるため、鋳造スタート部に相当するスラブの割れは 0.3個/mと極めて少なかった。 On the other hand, the present invention since the powder amount flowing between the mold wall and the slab becomes possible to uniform cooling of the cast piece in a sufficient and mold, cracking of the slab corresponding to the casting start portion is extremely 0.3 pieces / m It was small.

【0012】従って、本発明がスタート部のパウダ溶融厚不足によって生じる表面の割れに対して極めて効果的であることが確認された。 Accordingly, that the present invention is extremely effective for surface cracks caused by the powder insufficient melting thickness of the start portion was observed.

【0013】 [0013]

【表1】 [Table 1]

【0014】実施例2 0.0015〜0.0025%C、0.09〜0.12%Mn、0.006 〜0.012 [0014] Example 2 0.0015~0.0025% C, 0.09~0.12% Mn, 0.006 ~0.012
%P、0.06〜0.010 %S、0.035 〜0.045 %Alを含有する極低炭素溶鋼を前述の実施例1と同様の方法で鋳造し、スタート部に相当する鋳片長さ3mに相当する位置の冷延鋼板の炭素分析を行った。 % P, 0.06~0.010% S, 0.035 to ultra low carbon molten steel containing ~0.045% Al was cast in the same manner as in Example 1 described above, the position of the cold corresponding to the slab length 3m corresponding to the start portion It was carbon analysis of rolled steel sheet. 一方、比較例も前述した従来法と同じ方法で鋳造し、同じくスタート部3mに相当する冷延鋼板の炭素分析を行った。 On the other hand, comparative examples were cast in the same manner as the conventional method described above, it was also subjected to carbon analysis of cold-rolled steel sheet, which corresponds to the start portion 3m. 結果を表2に示す。 The results are shown in Table 2.

【0015】本発明例では、溶解炉内モールドパウダ中の炭素は全て燃焼し、鋳型内に添加する段階では炭素が含まれていないので、タンディッシュ(T/D)内溶鋼と冷延鋼板の炭素濃度がほとんど変化していないのに比べ、比較例では冷延鋼板の炭素濃度がタンディッシュ内溶鋼の炭素量より約6ppm 上昇している。 [0015] In examples of the present invention, all the carbon in the melt furnace in mold powder combustion, since the step of adding into the mold does not contain carbon, tundish (T / D) in the molten steel and the cold-rolled steel sheet compared to hardly change the carbon concentration, in the comparative example is the concentration of carbon cold-rolled steel sheet is increased by about 6ppm than the amount of carbon tundish molten steel. この実験とは別に同一の鋳造条件で電極を使った加熱なし溶融モールドパウダを添加した実験を行ったが、添加したパウダが溶鋼メニスカス部で凝固し、鋳片内部にディッケル欠陥が発生した。 The addition was the experiment without heating molten mold powder using electrodes was carried out separately by the same casting conditions as the experiment, the added powder is solidified molten steel meniscus, deckle defects generated inside the slab.

【0016】この実施例からも本発明が浸炭に対して有効であることが確認された。 [0016] It is also the invention of this embodiment is effective against carburization was confirmed.

【0017】 [0017]

【表2】 [Table 2]

【0018】前記の実施例では、モールドパウダを溶融させるためにシリコニット炉を用いたが、溶融させるためであればその炉の種類は限定しない。 [0018] In the above embodiment uses a siliconit furnace in order to melt the mold powder, the type of furnace so long to melt is not limited. また、電極径、 Further, electrode diameter,
電極数、および通電量も、添加する溶融パウダが大気への放冷によって凝固しない熱量以上であれば特に限定はしない。 Number electrodes, and current amount, the molten powder to be added is not limited particularly as long as more than the amount of heat which is not coagulated by cooling into the atmosphere.

【0019】 [0019]

【発明の効果】本発明は、連続鋳造のスタート時に溶融させたモールドパウダーを鋳型内に添加し、添加した溶融パウダー層内に浸漬した電極に通電し抵抗加熱するようにしたから、鋳造スタート部の割れや浸炭が回避され鋳片歩留りの向上が達成できる。 According to the present invention, since the melted during the continuous casting start mold powder added to a mold and energized immersed electrodes to melt the powder layer was added so as to resistance heating, casting start portion improvement of the cracks and carburizing is avoided slab yield can be achieved.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明の構成を示す概略断面図である。 1 is a schematic sectional view showing the configuration of the present invention.

【符号の説明】 DESCRIPTION OF SYMBOLS

1 溶融モールドパウダ 2 溶鋼炉 3 電極 4 鋳型 5 凝固シェル 6 ダミーバー 7 タンディッシュ 8 溶鋼 9 イマージョンノズル 10 供給樋 1 molten mold powder 2 molten steel furnace 3 electrode 4 template 5 solidified shell 6 dummy bar 7 tundish 8 molten steel 9 Immersion nozzle 10 supply trough

───────────────────────────────────────────────────── フロントページの続き (72)発明者 田口 整司 千葉県千葉市中央区川崎町1番地 川崎製 鉄株式会社技術研究本部内 (72)発明者 関口 浩 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 ────────────────────────────────────────────────── ─── of the front page continued (72) inventor Taguchi SeiTsukasa Chiba City, Chiba Prefecture, Chuo-ku, Kawasaki-cho, address 1 Kawasaki-made iron Co., Ltd. technology research in the headquarters (72) inventor Hiroshi Sekiguchi Kurashiki, Okayama Prefecture Mizushimakawasakidori 1-chome ( address a tooth) Kawasaki Steel Co., Ltd. in the Mizushima Works

Claims (1)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】 鋼を連続鋳造するスタート時において、 [Claim 1] at the time of the start of the continuous casting of steel,
    予め溶融せしめたモールドパウダを連鋳鋳型内に添加したのち、一対以上の電極をその溶融パウダに浸漬して抵抗加熱をすることを特徴とする表面性状に優れた連鋳鋳片の製造方法。 After the addition of mold powder which was allowed previously melted continuous casting in a mold, continuous casting slab manufacturing method having excellent surface properties, characterized in that the resistance heating by immersing one or more pairs of electrodes in the molten powder.
JP16911592A 1992-06-26 1992-06-26 Production of continuously cast slab excellent in surface characteristic Pending JPH067907A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16911592A JPH067907A (en) 1992-06-26 1992-06-26 Production of continuously cast slab excellent in surface characteristic

Publications (1)

Publication Number Publication Date
JPH067907A true JPH067907A (en) 1994-01-18

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Country Status (1)

Country Link
JP (1) JPH067907A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006035274A (en) * 2004-07-28 2006-02-09 Jfe Steel Kk Method for charging fused powder
WO2007148940A1 (en) 2006-06-23 2007-12-27 Posco Continuous casting machine using molten mold flux
JP2009541062A (en) * 2006-06-23 2009-11-26 ポスコ Continuous casting apparatus and method using molten mold flux

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006035274A (en) * 2004-07-28 2006-02-09 Jfe Steel Kk Method for charging fused powder
JP4617756B2 (en) * 2004-07-28 2011-01-26 Jfeスチール株式会社 Method of charging molten powder
WO2007148940A1 (en) 2006-06-23 2007-12-27 Posco Continuous casting machine using molten mold flux
JP2009541062A (en) * 2006-06-23 2009-11-26 ポスコ Continuous casting apparatus and method using molten mold flux
JP2009541061A (en) * 2006-06-23 2009-11-26 ポスコ Continuous casting equipment using molten mold flux
EP2446982A1 (en) 2006-06-23 2012-05-02 Posco Continuous casting machine and method using molten mold flux
US8191607B2 (en) 2006-06-23 2012-06-05 Posco Continuous casting machine using molten mold flux
US8210238B2 (en) 2006-06-23 2012-07-03 Posco Continuous casting machine and method using molten mold flux

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