JP2790420B2 - Carbon steel slab by twin roll continuous casting and its manufacturing method - Google Patents
Carbon steel slab by twin roll continuous casting and its manufacturing methodInfo
- Publication number
- JP2790420B2 JP2790420B2 JP26752993A JP26752993A JP2790420B2 JP 2790420 B2 JP2790420 B2 JP 2790420B2 JP 26752993 A JP26752993 A JP 26752993A JP 26752993 A JP26752993 A JP 26752993A JP 2790420 B2 JP2790420 B2 JP 2790420B2
- Authority
- JP
- Japan
- Prior art keywords
- limiting plate
- casting
- roll
- carbon steel
- contact limiting
- 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
Landscapes
- Continuous Casting (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は双ロール式連続鋳造によ
る炭素鋼鋳片の製造に関する。The present invention relates to the production of carbon steel slabs by twin roll continuous casting.
【0002】[0002]
【従来の技術】図2は例えば特開昭58−148056
号公報に記載されている双ロール式連続鋳造の説明図で
ある。製造する鋳片6の板厚tmmに相当する間隔を設
けて、互いに平行にかつ水平に配されて矢印8方向に回
動する2本の鋳造ロール1−1と1−2を配する。鋳造
ロールの両端部には鋳造ロール1−1,1−2の側面に
密着させて側堰12(12')を配する。鋳造ロールの上
部と側堰とで形成した湯溜り2に溶湯5を注入すると、
溶湯は鋳造ロール表面に凝固シェル3−1,3−2を形
成するが、凝固シェル3−1,3−2は鋳造ロールの回
動に追従して矢印8方向に移動しながら成長し、鋳造ロ
ール1−1と1−2の最小間隙部(キス点)4から鋳片6
となって取り出される。2. Description of the Related Art FIG.
FIG. 1 is an explanatory view of a twin-roll type continuous casting described in Japanese Patent Laid-Open Publication No. H10-209,878. Two casting rolls 1-1 and 1-2 which are arranged in parallel and horizontally to rotate in the direction of arrow 8 are arranged at intervals corresponding to the plate thickness tmm of the slab 6 to be manufactured. Side dams 12 (12 ') are arranged at both ends of the casting roll in close contact with the side surfaces of the casting rolls 1-1 and 1-2. When the molten metal 5 is poured into the pool 2 formed by the upper part of the casting roll and the side dam,
The molten metal forms solidified shells 3-1 and 3-2 on the surface of the casting roll, and the solidified shells 3-1 and 3-2 grow while moving in the direction of arrow 8 following the rotation of the casting roll. From the minimum gap (kiss point) 4 between the rolls 1-1 and 1-2 to the slab 6
It is taken out as.
【0003】図3は接触制限板9を用いた双ロール式連
続鋳造の説明図である。この際には、接触制限板9をそ
の下端10を鋳造ロール1−1,1−2の表面に近接し
て配し、接触制限板と側面堰(図示しない。図2参照)
とで形成される湯溜り2に溶湯5を注入する。FIG. 3 is an explanatory view of a twin-roll type continuous casting using a contact limiting plate 9. In this case, the contact limiting plate 9 is disposed with its lower end 10 close to the surfaces of the casting rolls 1-1 and 1-2, and the contact limiting plate and the side weir (not shown; see FIG. 2).
The molten metal 5 is poured into the basin 2 formed by the above steps.
【0004】図2の例では凝固シェル3−1,3−2の
形成は溶湯の浴面7で開始するために、溶湯の浴面7上
にスカム等が浮遊していると、このスカムが溶湯とドラ
ム間に巻きこまれて、ドラムによる冷却が不均一とな
り、鋳片の表面にスカム疵や割れが発生するという問題
点がある。図3の例では凝固シェル3−1,3−2の形
成は溶湯の浴面7よりも下方の、例えば11で開始す
る。このため溶湯の浴面7上にスカム等が浮遊していて
もスカム等が溶湯とドラム間に巻き込まれることがな
く、スカム疵や割れの発生を有効に防止することができ
る。In the example of FIG. 2, since the formation of the solidified shells 3-1 and 3-2 starts on the bath surface 7 of the molten metal, if scum or the like is floating on the bath surface 7 of the molten metal, the scum is formed. It is wrapped between the molten metal and the drum, so that the cooling by the drum becomes uneven and there is a problem that scum flaws and cracks occur on the surface of the slab. In the example of FIG. 3, the formation of the solidified shells 3-1 and 3-2 starts below the molten metal bath surface 7, for example, at 11. Therefore, even when scum or the like floats on the bath surface 7 of the molten metal, the scum or the like is not caught between the molten metal and the drum, and generation of scum flaws and cracks can be effectively prevented.
【0005】[0005]
【発明が解決しようとする課題】図2、図3の双ロール
式連続鋳造によると厚さが0.5〜6mmの板状の炭素
鋼の鋳片を製造でき、このために後の冷間圧延工程を大
幅に簡易にすることができる。しかし本発明者等の知見
によると、格別の工夫を行わないで図2、図3の方法で
製造した炭素鋼鋳片は、鋳片の結晶粒が粗く、このため
延性が不十分であるという問題点がある。本発明は、鋳
片の結晶粒が微細な炭素鋼鋳片とその製造方法の提供を
課題としている。According to the twin-roll type continuous casting shown in FIGS. 2 and 3, a plate-like carbon steel slab having a thickness of 0.5 to 6 mm can be produced. The rolling process can be greatly simplified. However, according to the findings of the present inventors, carbon steel slabs produced by the method shown in FIGS. 2 and 3 without any special ingenuity show that the slabs have coarse crystal grains and therefore have insufficient ductility. There is a problem. An object of the present invention is to provide a carbon steel slab having fine crystal grains and a method for producing the same.
【0006】[0006]
【課題を解決するための手段および作用】本発明者等
は、図3の連続鋳造法において、接触制限板9の位置を
変えると、得られる鋳片6の一次晶の大きさが変化する
事を知得して本発明をなすに至った。The present inventors have found that in the continuous casting method shown in FIG. 3, when the position of the contact limiting plate 9 is changed, the size of the primary crystal of the obtained slab 6 changes. And obtained the present invention.
【0007】即ち本発明においては、接触制限板9を用
いた双ロール式連続鋳造を行う際に、接触制限板9の下
端10を溶湯の浴面7から20mm以上下方で、かつ浴
面から鋳造ロール半径の3/4の深さの位置より上方に
設定し、同時に接触制限板の下端と鋳造ロール3−2の
表面との間隔を0.1mm以上かつ1mm以下に保って
炭素鋼鋳片を鋳造する。That is, in the present invention, when performing twin-roll continuous casting using the contact limiting plate 9, the lower end 10 of the contact limiting plate 9 is cast at least 20 mm below the molten metal bath surface 7 and from the bath surface. The carbon steel slab is set above the depth of 3/4 of the roll radius, and at the same time, the distance between the lower end of the contact limiting plate and the surface of the casting roll 3-2 is kept at 0.1 mm or more and 1 mm or less. Casting.
【0008】図1は、接触制限板の下端10と鋳造ロー
ルの表面との間隔を0.1mm以上で1mm以下に保っ
て、接触制限板の設定深さを変えた場合の鋳片の結晶粒
の大きさを示す図である。尚製造した鋳片の厚さは1.
5mm〜6mmである。結晶粒の大きさは、鋳片の縦断
面をピクリン酸でマクロエッチし表面から板厚の1/4
の厚さの範囲を100倍の光学顕微鏡写真で検査した1
0視野の結晶粒の大きさの平均値である。FIG. 1 shows the crystal grains of a slab when the set depth of the contact limiting plate is changed while the distance between the lower end 10 of the contact limiting plate and the surface of the casting roll is maintained at 0.1 mm or more and 1 mm or less. It is a figure which shows the magnitude of. The thickness of the slab was 1.
5 mm to 6 mm. The size of the crystal grain is 1/4 of the plate thickness from the surface by macro-etching the vertical section of the slab with picric acid.
The thickness range was examined with a 100 × optical micrograph.
This is the average value of the size of the crystal grains in the zero visual field.
【0009】図1にみられる如く、接触制限板の下端を
浴面から20mm以上下方に配すると、鋳片の結晶粒は
顕著に微細化する。しかし浴面から鋳造ロールの半径の
3/4を超えた深さに配すると、凝固シェルの生長が不
十分で、鋳片は鋳造ロールの直下で破断し易い。従って
本発明では接触制限板の下端は浴面下20mmよりも下
方で鋳造ロールの半径の3/4よりも上方に配する。As shown in FIG. 1, when the lower end of the contact limiting plate is arranged at least 20 mm below the bath surface, the crystal grains of the slab are remarkably refined. However, if it is arranged at a depth exceeding 3/4 of the radius of the casting roll from the bath surface, the growth of the solidified shell is insufficient, and the slab is easily broken immediately below the casting roll. Therefore, in the present invention, the lower end of the contact limiting plate is disposed below 20 mm below the bath surface and above 3/4 of the radius of the casting roll.
【0010】本発明では接触制限板の下端と鋳造ロール
の表面との隙間を0.1mm〜1.0mmに設定する。こ
の隙間が0.1mm未満では溶湯からの熱による変形に
より、接触制限板がドラムに接触し、接触制限板が摩耗
しまた耐火物製の接触制限板が鋳造ロールの表面に接触
して、鋳造ロールの表面に疵を多発させる。また接触制
限板の下端と鋳造ロールの表面との隙間が1.0mmを
超えると、この隙間に溶湯が湯差しして、鋳片の表面性
状が損なわれる。In the present invention, the gap between the lower end of the contact limiting plate and the surface of the casting roll is set to 0.1 mm to 1.0 mm. If the gap is less than 0.1 mm, the contact limiting plate comes into contact with the drum due to deformation due to heat from the molten metal, the contact limiting plate wears, and the contact limiting plate made of refractory comes into contact with the surface of the casting roll. Causes numerous flaws on the roll surface. If the gap between the lower end of the contact limiting plate and the surface of the casting roll exceeds 1.0 mm, molten metal is poured into this gap, and the surface properties of the cast slab are impaired.
【0011】接触制限板の下端を溶湯の浴面下20mm
よりも下方に設定すると、鋳片の金属組織が微細化する
理由は、必ずしも詳かではないが、下記の如くに推考さ
れる。即ち、接触制限板がない場合や、接触制限板の下
端10が溶湯の浴面下20mmよりも上方にある場合
は、形成した凝固シェルの熱変形によって、図2および
図3で鋳造ロール1−2と凝固シェル3−2との間には
空気断熱層が形成され、この空気断熱層が凝固シェル3
−2の急速な冷却を妨げ、この結果凝固シェルは粗い金
属組織となる。The lower end of the contact limiting plate is set at 20 mm below the bath surface of the molten metal.
If it is set lower than this, the reason why the metal structure of the slab becomes finer is not necessarily clear, but is presumed as follows. That is, when there is no contact limiting plate or when the lower end 10 of the contact limiting plate is above 20 mm below the bath surface of the molten metal, the casting roll 1-1 in FIGS. 2 is formed between the solidified shell 3-2 and the solidified shell 3-2.
-2, which prevents rapid cooling of the solidified shell, resulting in a coarse metallographic structure.
【0012】図3で接触制限板の下端10が溶湯の浴面
下20mmよりも下方にある場合には、溶湯の静圧によ
って凝固シェルが鋳造ロールの表面に押しつけられ、空
気断熱層の形成が阻止されあるいは空気断熱層が薄くな
って、凝固シェル3−2の急速な冷却を促し、この結果
凝固シェルは結晶粒が50μm以下の微細な金属組織と
なる。In FIG. 3, when the lower end 10 of the contact limiting plate is located below 20 mm below the bath surface of the molten metal, the solidified shell is pressed against the surface of the casting roll by the static pressure of the molten metal to form an air insulating layer. The solidified shell 3-2 is rapidly cooled by being blocked or the air heat insulating layer becomes thin, and as a result, the solidified shell has a fine metal structure with crystal grains of 50 μm or less.
【0013】以上述べた如く、本発明の双ロール式連続
鋳造による炭素鋼鋳片は、厚さが0.5〜6mmで表面
から板厚の1/4の深さ迄が平均で50μm以下の結晶
粒で形成されていることを特徴とする。As described above, the carbon steel slab obtained by the twin-roll continuous casting according to the present invention has a thickness of 0.5 to 6 mm and an average depth of 50 μm or less from the surface to a depth of 4 of the plate thickness. It is characterized by being formed of crystal grains.
【0014】[0014]
【実施例】本発明者等は、直径が1200mmで胴長が
800mmの鋳造ロールを周速度80m/分で回動させ
て、[C]含有量が0.04%の低炭素鋼の溶湯を注入
し、厚さが3mmの双ロール式連続鋳造鋳片を作成し
た。DETAILED DESCRIPTION OF THE INVENTION The present inventors rotated a casting roll having a diameter of 1200 mm and a body length of 800 mm at a peripheral speed of 80 m / min to obtain a molten low carbon steel having a [C] content of 0.04%. Injection was performed to prepare a twin-roll continuous cast slab having a thickness of 3 mm.
【0015】この際、本発明例では、接触制限板を用
い、接触制限板の下端を浴面下120mmに、かつ接触
制限板の下端と鋳造ロールの表面との間隔を0.1〜1.
0mmに保って鋳造した。この本発明で得られた鋳片の
表面から1/4の金属組織は平均で32μmの結晶粒で
形成されていた。尚この本発明例で得られた鋳片のL方
向の伸びは20%で十分な延性を備えていた。At this time, in the example of the present invention, a contact limiting plate is used, the lower end of the contact limiting plate is set to 120 mm below the bath surface, and the distance between the lower end of the contact limiting plate and the surface of the casting roll is set to 0.1 to 1.1.
The casting was maintained at 0 mm. The metal structure of 1/4 from the surface of the cast slab obtained in the present invention was formed of crystal grains of 32 μm on average. Incidentally, the elongation in the L direction of the cast slab obtained in this example of the present invention was 20% and was sufficiently ductile.
【0016】また比較例として、接触制限板を使用しな
いで鋳造を行った。尚他の鋳造条件は本発明例と同じで
ある。この比較例で得られた鋳片の表面から1/4の金
属組織は平均で87μmの結晶粒で形成されていた。こ
の比較例で得られた鋳片のL方向の伸びは12%で、本
発明例の鋳片に比べて延性が劣っている。As a comparative example, casting was performed without using a contact limiting plate. The other casting conditions are the same as those of the present invention. From the surface of the cast slab obtained in this comparative example, 1/4 of the metal structure was formed of 87 μm average crystal grains. The elongation in the L direction of the slab obtained in this comparative example is 12%, which is inferior to the slab of the present invention in ductility.
【0017】[0017]
【発明の効果】本発明によると、十分な延性を備えた、
結晶粒が微細な炭素鋼鋳片を製造する事ができる。また
本発明では接触制限板を用いるために鋳片にはスカム疵
の発生がなく、また凝固シェルは溶湯の浴面7から十分
離れた下方の位置で形成を開始するため、溶湯の浴面7
の揺動の影響を受ける事が少なく、溶湯の浴面の揺動に
起因して通常発生する鋳片表面の湯じわ疵も大幅に低減
する。According to the present invention, with sufficient ductility,
A carbon steel slab with fine crystal grains can be manufactured. Further, in the present invention, since the contact limiting plate is used, no scum is generated on the cast slab, and the solidified shell starts to be formed at a position sufficiently distant from the molten metal bath surface 7.
The influence of the rocking of the molten metal is small, and the wrinkles on the surface of the slab, which usually occur due to the rocking of the bath surface of the molten metal, are greatly reduced.
【図面の簡単な説明】[Brief description of the drawings]
【図1】は接触制限板の設定位置と鋳片の結晶粒の大き
さの関係の説明図。FIG. 1 is an explanatory diagram of a relationship between a set position of a contact limiting plate and a size of a crystal grain of a slab.
【図2】は通常の双ロール式連続鋳造の説明図。FIG. 2 is an explanatory view of a normal twin-roll continuous casting.
【図3】は接触制限板を有する双ロール式連続鋳造の説
明図。FIG. 3 is an explanatory view of a twin-roll continuous casting having a contact limiting plate.
1−1,1−2:鋳造ロール、 2:湯溜り、 3−
1,3−2:凝固シェル、 4:キス点、 5:溶湯、
6:鋳片、 7:溶湯の浴面、 8:鋳造ロールの回
動方向、 9:接触制限板、 10:接触制限板の下
端、 11:凝固シェルの形成の開始位置、 12(1
2'):側堰。1-1, 1-2: casting roll, 2: pool, 3-
1,3-2: solidified shell, 4: kiss point, 5: molten metal,
6: cast slab, 7: bath surface of molten metal, 8: rotating direction of casting roll, 9: contact limiting plate, 10: lower end of contact limiting plate, 11: start position of formation of solidified shell, 12 (1)
2 '): Side dam.
フロントページの続き (56)参考文献 特開 平6−246399(JP,A) 特開 平6−246398(JP,A) 特開 平3−193245(JP,A) 特開 昭63−195253(JP,A) 特開 昭63−119949(JP,A) (58)調査した分野(Int.Cl.6,DB名) B22D 11/06 330 B22D 11/00Continuation of the front page (56) References JP-A-6-246399 (JP, A) JP-A-6-246398 (JP, A) JP-A-3-193245 (JP, A) JP-A-63-195253 (JP) , A) JP-A-63-119949 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) B22D 11/06 330 B22D 11/00
Claims (2)
/4の深さ迄が50μm以下の結晶粒で形成されている
ことを特徴とする、双ロール式連続鋳造による炭素鋼鋳
片。(1) a thickness of 0.5 to 6 mm and a thickness of 1
A carbon steel slab by twin-roll continuous casting, characterized in that crystal grains having a depth of up to / 4 are formed of crystal grains of 50 μm or less.
行う際に、接触制限板の下端を溶湯浴面から20mm以
上下方で、かつ浴面から鋳造ロール半径の3/4の深さ
の位置より上方に設定し、同時に接触制限板の下端と鋳
造ロールの表面との間隔を0.1mm以上かつ1mm以
下に保って炭素鋼鋳片を鋳造することを特徴とする、双
ロール式連続鋳造による炭素鋼鋳片の製造方法。2. A twin-roll type continuous casting using a contact limiting plate, wherein the lower end of the contact limiting plate is at least 20 mm below the molten metal bath surface and 3/4 of the casting roll radius from the bath surface. , And at the same time, a carbon steel slab is cast while maintaining the distance between the lower end of the contact limiting plate and the surface of the casting roll at 0.1 mm or more and 1 mm or less, twin roll continuous. A method for producing carbon steel slabs by casting.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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JP26752993A JP2790420B2 (en) | 1993-10-26 | 1993-10-26 | Carbon steel slab by twin roll continuous casting and its manufacturing method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP26752993A JP2790420B2 (en) | 1993-10-26 | 1993-10-26 | Carbon steel slab by twin roll continuous casting and its manufacturing method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07116787A JPH07116787A (en) | 1995-05-09 |
JP2790420B2 true JP2790420B2 (en) | 1998-08-27 |
Family
ID=17446100
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP26752993A Expired - Fee Related JP2790420B2 (en) | 1993-10-26 | 1993-10-26 | Carbon steel slab by twin roll continuous casting and its manufacturing method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2790420B2 (en) |
-
1993
- 1993-10-26 JP JP26752993A patent/JP2790420B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH07116787A (en) | 1995-05-09 |
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