JPH04197560A - Method for continuously casting metal sheet - Google Patents

Abstract

PURPOSE:To enable continuous casting of a sheet without influenced by scum inevitably produced by injecting inert gas to center in pouring basin part and collecting scum floated on an surface of the pouring basin part to side weir side. CONSTITUTION:The inert gas is injected to near the center of pouring basin part 5 concentrating the scum and the inert gas flow is formed toward the side weir 3, 4 sides from the center part just above the pouring basin part 5, and the scum is guided to the side weir 3, 4 sides with the inert gas flow and collected to the side weir 3, 4 sides in the pouring basin part 5. The scum collected at this side weir side comes to contain in the sheet by drawing together with molten steel, but as the scum containing part is concentrated to width end of the sheet, bad influence is not given to product quality. Because, the width end of sheet can be removed in the following process of slitting, etc., and the product having no scum containing part is produced.

Description

【発明の詳細な説明】 （産業上の利用分野〕 この発明は、溶融金属、例えば溶鋼から厚さ約１０＝以
下の薄鋼板を直接鋳造する双ロール式の連続鋳造方法、
中でも溶鋼を注湯ノズルと傾斜板とを介して水冷鋳造ロ
ール間の湯溜り部に供給して直接薄板を連続鋳造する方
法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a twin-roll continuous casting method for directly casting a thin steel plate with a thickness of about 10= or less from molten metal, such as molten steel;
In particular, the present invention relates to a method for directly continuously casting thin plates by supplying molten steel to a pool between water-cooled casting rolls through a pouring nozzle and an inclined plate.

［従来の技術］ この種の連続鋳造方法は、厚さ数ミリ程度の熱延板相当
板を溶鋼から直接鋳造する技術であって、いわゆる厚さ
１００〜３００ＩＩＩＩＩｌ程度のスラブを直接鋳造す
る方法や厚さ１ｍｍ未満の急冷薄帯を鋳造する方法に比
べると、独自の工夫が必要である。[Prior art] This type of continuous casting method is a technology for directly casting a plate equivalent to a hot-rolled plate with a thickness of about several millimeters from molten steel, and is a method for directly casting a slab with a thickness of about 100 to 300 mm. Compared to the method of casting a quenched ribbon with a thickness of less than 1 mm, unique innovations are required.

すなわち、薄板の連続鋳造では、湯溜り部が隣接する鋳
造ロール間の挟間に形成されるため、この湯溜り部の場
面が注湯によって変動すると、ロール面上に生成する凝
固シェルの性状に影響を及ぼすことになり、得られる薄
鋼板の表面性状は劣化する。In other words, in continuous casting of thin plates, a pool is formed between adjacent casting rolls, so if the position of the pool changes due to pouring, it will affect the properties of the solidified shell that forms on the roll surface. As a result, the surface quality of the obtained thin steel sheet deteriorates.

従って、薄鋼板の連続鋳造における注湯は、タンデイツ
シュ内溶鋼を注湯ノズルから湯溜り部りこ供給するとき
、かかる注湯ノズル真下に傾斜板を配置し、溶銅落下流
による湯溜り部表面の波立ちを抑制していた。Therefore, when pouring molten steel in the continuous casting of thin steel sheets, when the molten steel in the tundish is supplied from the pouring nozzle to the molten metal pool, an inclined plate is placed directly below the molten metal pouring nozzle. It suppressed the ripples.

（発明が解決しようとする課題］ さて、かかる薄板の連続鋳造に限らず、スラブや薄帯な
どの連続鋳造一般において、溶鋼中の非金属介在物を含
む酸化物（以下スカムと示す）は、鋳片の表面性状を劣
化することから、従来は不活性ガス雰囲気に保つ等の手
段で対処している。(Problems to be Solved by the Invention) Now, not only in continuous casting of such thin plates but also in general continuous casting of slabs and ribbons, oxides containing nonmetallic inclusions (hereinafter referred to as scum) in molten steel are Since this deteriorates the surface quality of the slab, conventional measures such as keeping it in an inert gas atmosphere have been taken as a countermeasure.

しかしながら、スカムの生成を完全に防止することは難
しく、特に上記の注湯ノズルと傾斜板とを介して注湯を
行う場合は、例えばスラブの連続鋳造におけるイマージ
ョンノズルでの注湯と比較して、溶鋼が湯溜り部に流下
するまでの経路が長いためスカムの生成率が高く、従っ
て、スカムの取扱いが製品の表面性状に与える影響は甚
大である。However, it is difficult to completely prevent the formation of scum, especially when pouring through the above-mentioned pouring nozzle and inclined plate, compared to pouring with an immersion nozzle in continuous slab casting, for example. Since the path for the molten steel to flow down to the sump is long, the rate of scum formation is high, and therefore, the handling of scum has a significant effect on the surface quality of the product.

そこでこの発明は、不可避に生成するスカムに影響され
ることのない薄板の連続鋳造を有利に実現する方法につ
いて提案することを目的とする。Therefore, an object of the present invention is to propose a method for advantageously realizing continuous casting of thin plates without being affected by the scum that inevitably occurs.

〔課題を解決するための手段〕[Means to solve the problem]

本発明者らは、スカムと製品品質との関係についで種々
の実験を行って検討したところ、湯溜り部表面に浮遊す
るスカムを、湯溜り部の、鋳造した薄板の幅端に相当す
る区域に集めることによって製品品質が阻害されないこ
とを見出し、この発明を完成するに到った。The present inventors conducted various experiments and investigated the relationship between scum and product quality, and found that scum floating on the surface of the tundish pool was removed from the area of the tundish pool that corresponded to the width end of the cast thin plate. It was discovered that product quality was not impaired by concentrating the materials, and this invention was completed.

すなわちこの発明は、溶融金属を、一対の鋳造ロールお
よびサイド堰で区画した湯溜り部に、注湯ノズルとその
直下に配置する傾斜板を介して供給し、鋳造ロール面で
の急冷凝固を強いて薄板を直接鋳造するに当たり、 上記湯溜り部表面における鋳造ロール軸方向の中央付近
へ向けて、鋳造ロール側から不活性ガスを吹付け、湯溜
り部表面に浮遊するスカムをサイド堰側に集めることを
特徴とする金属薄板の連続鋳造方法である。In other words, the present invention supplies molten metal to a pool defined by a pair of casting rolls and a side weir through a pouring nozzle and an inclined plate placed directly below the pouring nozzle, and forces the metal to rapidly solidify on the surface of the casting rolls. When directly casting a thin plate, inert gas is blown from the casting roll side toward the center of the casting roll axial direction on the surface of the sump, and the scum floating on the surface of the sump is collected on the side weir side. This is a method for continuous casting of thin metal sheets.

さて、第１図にこの発明で使用する薄板連続鋳造機を示
し、さらに図２に第１図のｎ−ｎ’線に沿う断面を示す
。Now, FIG. 1 shows a thin plate continuous casting machine used in the present invention, and FIG. 2 shows a cross section taken along line nn' in FIG. 1.

図中１，２は、内部を水冷した１対の鋳造ロールおよび
３，４は鋳造ロール１，２の端面に密接配置した１対の
サイド堰で、これら鋳造ロール１゜２およびサイド堰３
，４にて湯溜り部５を区画してなる。また、６はタンデ
イツシュ内溶鋼を湯溜り部５へ供給する注湯ノズル、７
は注湯ノズル６の直下乙こ配置した傾斜板で、注湯ノズ
ル６がらの溶鋼を傾斜板７を介して湯溜り５へ緩やかに
流下させる。さらに８，９は湯溜り部５表面へ向けて不
活性ガスを吹付けるノズルである。In the figure, 1 and 2 are a pair of casting rolls whose interiors are water-cooled, and 3 and 4 are a pair of side weirs closely arranged on the end faces of the casting rolls 1 and 2.
, 4 divides the hot water reservoir 5. Further, 6 is a pouring nozzle that supplies the molten steel in the tundish to the sump 5;
is an inclined plate disposed directly below the pouring nozzle 6, which allows the molten steel from the pouring nozzle 6 to gently flow down into the molten metal pool 5 via the inclined plate 7. Furthermore, 8 and 9 are nozzles that spray inert gas toward the surface of the water reservoir 5.

この発明に従う方法は、湯溜り部５の表面に浮遊するス
カムをノズル８，９から噴射する不活性ガスにてサイド
堰３または４側に吹き寄せることを特徴とする。The method according to the present invention is characterized in that the scum floating on the surface of the pool 5 is blown toward the side weir 3 or 4 using inert gas injected from nozzles 8 and 9.

すなわち、鋳造ロール１．２側に配したノズル８．９の
ノズル孔は、湯溜り部５の鋳造ロール軸方向の中央部か
そのややサイド堰３，４寄りを指向させて配置し、不活
性ガスの流れがサイド堰３゜４へ向かうようにするわけ
である。That is, the nozzle holes of the nozzles 8.9 arranged on the side of the casting roll 1.2 are arranged so as to be oriented toward the central part of the casting roll axial direction of the tundish part 5 or slightly closer to the side weirs 3 and 4. The gas flow is directed to the side weir 3°4.

ここにノズル８．９は鋳造ロール１．２の軸長のほぼ中
心付近に配置し、また鋳造ロール１と２との軸長中心を
結ぶ仮想線りに対する、不活性ガスの噴射方向の傾きθ
および湯溜り部５表面に対する同噴射方向の傾きαは、
それぞれ θ：　３０〜８０６．　　　α≦３０″とすることが好
ましい。Here, the nozzle 8.9 is arranged approximately near the center of the axial length of the casting roll 1.2, and the inert gas injection direction has an inclination θ with respect to an imaginary line connecting the axial length centers of the casting rolls 1 and 2.
And the inclination α of the same injection direction with respect to the surface of the hot water pool 5 is:
θ: 30 to 806, respectively. It is preferable that α≦30″.

なぜなら、角度θが３０″未満では側方にスカムを追い
やる効果が少なく、一方８０°を超えると中央付近に発
生したスカムをサイド堰側に追いやる効果がなくなる。This is because if the angle θ is less than 30″, there is little effect of driving scum to the side, while if it exceeds 80°, there is no effect of driving scum generated near the center toward the side weir.

また、角度αは、湯溜り部中の溶湯流を乱さないために
３０°以下にすることが有利で、さらには装置の構造上
の制約が許す範囲で小さくすることが好ましい。Further, the angle α is advantageously set to 30° or less in order not to disturb the flow of the molten metal in the sump, and furthermore, it is preferably set as small as the structural constraints of the apparatus allow.

さらに不活性ガスにはＡｒやＨｅが適合し、その総流量
は１００〜５００１　／ｍｉｎの範囲が好適である。Furthermore, Ar and He are suitable as the inert gas, and the total flow rate thereof is preferably in the range of 100 to 5001/min.

なお、図示例において、ノズル８，９は二叉としたが、
２本をノズルを用いて上記条件を満たすように配置して
もかまわない。また鋳造ロール１または２のいずれか一
方の側のみに設置してもよい。In addition, in the illustrated example, the nozzles 8 and 9 are bifurcated, but
Two of them may be arranged using nozzles so as to satisfy the above conditions. Alternatively, it may be installed only on one side of the casting roll 1 or 2.

〔作　用〕[For production]

双ロール形式の連続鋳造において、湯溜り部表面に浮遊
するスカムは、溶鋼流に導かれて主に湯溜り部の中央に
集まる傾向にあり、このスカムが溶鋼とともに湯溜り部
内部に引き込まれると、鋳造された薄板の幅中央にスカ
ムが集まって製品価値が著しく低下される。In twin-roll continuous casting, scum floating on the surface of the sump tends to be guided by the molten steel flow and collect mainly in the center of the sump, and when this scum is drawn into the sump with the molten steel, , scum collects in the center of the width of the cast thin plate, significantly reducing the product value.

そこでこの発明では、スカムの集中する湯溜り部中央付
近に不活性ガスを吹付け、湯溜り部の直上に上記中央部
からサイド堰側へ向かう不活性ガス流を形成し、この不
活性ガス流にてスカムをサイド堰側へ導き、湯溜り部の
サイド堰側（以下湯溜り側部と示す）へ集める。Therefore, in this invention, an inert gas is sprayed near the center of the pool where scum is concentrated, and an inert gas flow is formed directly above the pool from the center toward the side weir. The scum is guided to the side weir side and collected on the side weir side of the pool (hereinafter referred to as the pool side).

この湯溜り側部に集まったスカムも溶鋼とともに引き込
まれて薄板内に含まれることになるが、スカム含を部は
薄板の幅端に集中するため、製品品質に悪影響を与える
ことがない。なぜなら、薄板の幅端はスリットなどの後
工程で容易に除去することができ、スカム含有部のない
製品とすることが可能であるからである。The scum that collects on the sides of the pool is also drawn in with the molten steel and included in the thin plate, but since the scum is concentrated at the width end of the thin plate, it does not adversely affect product quality. This is because the width end of the thin plate can be easily removed in a subsequent process such as slitting, and a product without scum-containing parts can be obtained.

〔実施例〕〔Example〕

第１図に示した薄板連続鋳造機を用いて、幅６００ｍｍ
、厚さ２肛の５ＬＩＳ　３０４材相当のステンレス鋼板
を下記の条件に従って鋳造するに当たり、第１図に示し
たノズルをそれぞれ表１に示す角度θおよびαに従って
設置し、同様ムこ表１に示す流量で湯溜り部表面へ吹付
けた。Using the thin plate continuous casting machine shown in Figure 1, the width of 600 mm was
When casting a stainless steel plate equivalent to 5LIS 304 material with a thickness of 2 holes according to the following conditions, the nozzles shown in Fig. 1 were installed according to the angles θ and α shown in Table 1, respectively, and the angles θ and α shown in Table 1 were similarly set. It was sprayed onto the surface of the hot water pool at a high flow rate.

上記の鋳造で得られたｍ板の幅中央におけるスカム巻込
み個数について調べた結果を表１に併記し、さらに表１
のＮα１（適合例）およびト０６（比較例）に関しては
薄板幅方向のスカム巻込み個数について調べた結果を図
２（ａ）および（′ｂ）に示す。The results of investigating the number of scum rolled in at the center of the width of the m plate obtained by the above casting are listed in Table 1, and further Table 1
For Nα1 (conforming example) and To06 (comparative example), the number of scum rolled up in the width direction of the thin plate was investigated and the results are shown in FIGS. 2(a) and 2(′b).

表　　１ 合計２本のノズルを用いた例 本章：溶鋼流が乱れて鋳片割れ発生 〔発明の効果〕 この発明によれば、従来は湯溜り部表面の中央に浮遊し
溶鋼とともに巻き込まれて製品品質を阻害していたスカ
ムを、製品品質に影響を与えない湯溜り側部に集めるこ
とができ、よって高品質の薄板を安定して製造し得る。Table 1 Example using a total of two nozzles This chapter: Molten steel flow is disturbed and slab cracks occur [Effects of the invention] According to this invention, conventionally the molten steel floats in the center of the surface of the molten metal and gets caught up with the molten steel, resulting in poor product quality. The scum that was obstructing the process can be collected on the side of the pool where it does not affect the product quality, making it possible to stably manufacture high-quality thin plates.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、この発明に使用する薄板連続鋳造機の模式図
、 図２は、第１図のｎ−ｎ’線断面図、 図３（ａ）、（ｂ）は、薄板幅方向のスカム巻込み個数
を示すグラフである。 １．２・・・鋳造ロール、　　３，４・・・サイド堰、
５・・・湯溜り部、　６・・・注湯ノズル、７・・・傾
斜板、　８，９・・・ノズル特許出願人　日本冶金工業
株式会社 代理人　弁理士　　小　川　順　三 同　　弁理士　　中　村　盛　夫 第１図 第２図Fig. 1 is a schematic diagram of a continuous thin plate casting machine used in the present invention, Fig. 2 is a sectional view taken along line nn' in Fig. 1, and Fig. 3 (a) and (b) are scum in the width direction of the thin plate. It is a graph showing the number of rolled up pieces. 1.2...Casting roll, 3,4...Side weir,
5... Hot water reservoir portion, 6... Pouring nozzle, 7... Inclined plate, 8, 9... Nozzle patent applicant Nippon Yakin Kogyo Co., Ltd. agent Patent attorney Jun Ogawa Sando Patent attorney Naka Morio MuraFigure 1Figure 2

Claims (1)

【特許請求の範囲】 １、溶融金属を、１対の鋳造ロールおよびサイド堰で区
画した湯溜り部に、注湯ノズルとその直下に配置する傾
斜板を介して供給し、鋳造ロール面での急冷凝固を強い
て薄板を直接鋳造するに当たり、 上記湯溜り部表面における鋳造ロール軸方向の中央付近
へ向けて、鋳造ロール側から不活性ガスを吹付け、湯溜
り部表面に浮遊するスカムをサイド堰側に集めることを
特徴とする金属薄板の連続鋳造方法。[Claims] 1. Molten metal is supplied to a pool defined by a pair of casting rolls and a side weir through a pouring nozzle and an inclined plate placed directly below the pouring nozzle, and the molten metal is poured onto the casting roll surface. When directly casting a thin plate by forcing rapid solidification, inert gas is blown from the casting roll side toward the center of the surface of the molten metal pool in the axial direction of the casting roll, and the scum floating on the surface of the molten metal pool is removed from the side dam. A method for continuous casting of thin metal sheets, characterized by gathering on the side.