JPS583758A - Continous casting method for round billet - Google Patents

Abstract

PURPOSE:To remove inclusions through floatation, to prevent the wash off of solidified shells and to improve productivity by charging molten steel into a round mold while charging vortex motion in the molten steel. CONSTITUTION:Discharge holes 3 are provided on the rectangular section in the longitudinal direction of a nozzle 1 in the direction tangential to the bore of the nozzle. The angle of deflection thereof is set at such an angle at which the flow of molten steel is conducted to vortex movement and that the flow of molten steel does not collide directly against the solidified shell produced on the inside surface of a round mold. the number of the holes 3 provided is 2-6 and is determined by the charging speed and rate of the molten steel. The section of the holes 3 is round, elliptical, square or the like and is determined by taking the sticking and growing of inclusions in the molten steel, etc. into consideration.

Description

【発明の詳細な説明】 この発明は、非金属介在物が少くかつ高速鋳込、みを万
能にした丸ビレットの連続鋳造方法に関する。゛ 従来から連続鋳造においては一般造塊に対し非金属介在
物の鋳型内浮上除去は不利とされている。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous casting method for round billets that has fewer nonmetallic inclusions and is versatile in high-speed casting and milling. ``Continuous casting has traditionally been disadvantageous in removing non-metallic inclusions by floating them in the mold compared to general ingot making.

そのため鋳型内への溶鋼の注入には浸漬ノズル形状を工
夫して介在物０漫入を浅くする方法が種々試みられて、
いる。これまで浸漬ノズ〃の吐出孔の出口角度、あるい
は吐出孔の口径の大きさ、数、さらＫは断面形状等の研
究がなされているが、このような研究は一般的に角形鋳
型を用いる角ビレ１ットスヲプの連続鋳造に関するもの
で、この浸漬ノズルを丸形鋳型を用いる丸ビレツＦの連
続鋳造に適用した場合必ずしも好結果唸得られないのが
実情である。Therefore, various methods have been tried to inject molten steel into the mold by devising the shape of the immersion nozzle to reduce the amount of inclusions.
There is. Until now, studies have been conducted on the exit angle of the discharge hole of the immersion nozzle, the size and number of the discharge hole diameter, and the cross-sectional shape of the discharge hole, but such research is generally conducted on square molds using square molds. This relates to the continuous casting of one fillet sweep, and the reality is that when this immersion nozzle is applied to the continuous casting of round billet F using a round mold, good results are not necessarily obtained.

丸ビレットの連続鋳造においては一般的な角ビレツト２
ツブの連続鋳造に比べて断面が小さいために非金属介在
物の鋳型内での浮上除去率は小さくなる。その丸め浸漬
ノズル形状を従来の角ビレット、スヲプの場合と同様の
考え方で吐出流を速くすゐと、逆にその吐出流によｐ凝
固シェルが洗い流されて局部的に薄くなりグレータアウ
を等の事故をおこし易く、鋳込み速度をおそくする必要
があや生産性が低下する欠点があゐ。In continuous casting of round billets, common square billets 2 are used.
Since the cross section is smaller than that in continuous casting of a spout, the floating removal rate of nonmetallic inclusions within the mold is reduced. If the shape of the rounded immersion nozzle is changed to a conventional rectangular billet or swap, if the discharge flow is made faster, the discharge flow will wash away the p-coagulation shell, causing it to become locally thinner and cause grater out. The drawback is that accidents are easy to occur, and the need to slow down the casting speed reduces productivity.

この発明は、このような観点から介在物の浮上のためＫ
は溶鋼流をできるだけ速くシ、又凝固Ｖエルの洗い流し
を防止する丸め凝固シェルに直接衝突しない注入を行う
連続鋳造方法を提案す石−４のでその要旨とするとζろ
は、ノズル内径Ｏ接線方向に複数個の吐出孔を有する有
底Ｏ浸漬ツメＮを用いて、円形鋳型内の溶鋼流を渦運動
させながら注入することを特徴とする４のである。From this point of view, the present invention provides K
proposes a continuous casting method in which the molten steel flow is as fast as possible, and the injection is performed without directly colliding with the rounded solidified shell to prevent the solidified V-el from being washed away. Item 4 is characterized in that the molten steel flow in the circular mold is injected while swirling it using a bottomed O-immersion claw N having a plurality of discharge holes.

以下図面に基づいてこの発明を説明する。第１図Ｆｉ４
の発明に用いる浸漬ツメ〃を示す図である。The present invention will be explained below based on the drawings. Figure 1 Fi4
FIG. 3 is a diagram showing a dipping claw used in the invention of FIG.

（１）は浸漬ノズル本体であυ、鍔（２ンにより夛ンダ
ブＶユの注出孔に取付けられ為。（３）はこの発明ノズ
〜の吐出孔である。この吐出孔はノズルの長手方向直角
断面のノズル内径接線方向（θ角度）に設ける。この偏
向角度りは溶銅流を渦運動に導くも“　　、 ので、渦流の流速と渦角度によって決定されるが溶鋼流
が丸形鋳型内面に発生する凝固シェルに直接衝突しない
角度に決定すべきである。このような吐出孔（３）の数
は１１〜６孔設けるもので、溶鋼注入適度、注入量によ
って決定される。図（２）は２孔の場合を示し、（２）
は３孔の場合を示す。又吐出孔の断面は、丸形、橢円形
、角形等とするが、溶鋼中のム１．θ□等介在物の付着
成長等を考慮に入れて決定すべきである。(1) is the main body of the submerged nozzle, which is attached to the spout hole of the immersion nozzle by the collar (2 pins). (3) is the discharge hole of the nozzle of this invention. The nozzle is installed in the tangential direction (θ angle) of the inner diameter of the nozzle with a cross section perpendicular to the direction.This deflection angle guides the molten copper flow into a vortex motion. The angle should be determined so that it does not directly collide with the solidified shell generated on the inner surface.The number of such discharge holes (3) is 11 to 6 holes, and is determined by the molten steel injection mode and injection amount. 2) shows the case of 2 holes, (2)
indicates the case of 3 holes. The cross section of the discharge hole may be round, oval, square, etc.; It should be determined taking into consideration the adhesion and growth of inclusions such as θ□.

第２図は、この発明におけ石注入溶鋼の渦流の状態を示
す図である。吐出孔（８）より流出する溶鋼は矢印方向
に渦運動をしながら鋳込まれる。このよう１に溶鋼の流
れにより介在物は溶鋼中深く浸入することなく浮上しか
つ凝固Ｖ工Ｊ４／に捕捉された介在物社洗滌除去される
。を九溶鋼の流れが丸鋳型（４）の内面に生成する凝固
Ｖ工〜（５）に沿った渦運動であるため凝固Ｖ工μに直
接衝突することなくシェルが局部的に集中して洗われる
ようなことはなくなり均一な厚みの凝固Ｖ工〜が生成す
るものである。FIG. 2 is a diagram showing the state of vortex flow of stone-injected molten steel in the present invention. Molten steel flowing out from the discharge hole (8) is cast while making a swirling motion in the direction of the arrow. In this way, the inclusions float up due to the flow of the molten steel without penetrating deeply into the molten steel, and the inclusions captured by the solidification V-work J4 are washed away. Because the flow of molten steel is a vortex motion along the solidification V-shaped (5) formed on the inner surface of the round mold (4), the shell is locally concentrated and washed without directly colliding with the solidified V-shaped. This eliminates the occurrence of cracking and produces a solidified V-shaped piece with a uniform thickness.

実施例 ２８２ψの丸ビレットの連続鋳造にあたって、本発明方
法と、従来万券によって実施した。Example 2 Continuous casting of round billets with a diameter of 82 ψ was carried out using the method of the present invention and a conventional ten thousand billet.

使用した浸漬ノズルの仕様を第１表に示す。Table 1 shows the specifications of the immersion nozzle used.

笈１表 連続鋳造条件を第２表に示す。1 table of koji Continuous casting conditions are shown in Table 2.

第　　８　　表 鋳造中に丸鋳型内面のシェル厚みを測定しその不均一性
を測定した。第３図は各実施例における凝固Ｖ工〃不均
一度を示す図である。横軸は各浸漬ノズルを示し、縦軸
は凝固Ｖ工〃不均一度（厚み差の比）である。図で明ら
かなように１本発明法Ｎｏ、１．２にシける凝固シェル
不均一度は従来法Ｎ＠４４　Ｋ比較して低く均一な凝固
シェル厚みが得られ、従来プレークアウＦ等のために鋳
込速度をおそくしてい丸ものがそのおそれがなくな９鋳
込逮度が向上した。Table 8: During casting, the shell thickness of the inner surface of the round mold was measured and its non-uniformity was measured. FIG. 3 is a diagram showing the degree of non-uniformity of the solidification V process in each example. The horizontal axis shows each immersion nozzle, and the vertical axis shows the solidification V process non-uniformity (ratio of thickness difference). As is clear from the figure, the non-uniformity of the solidified shell in method No. 1 of the present invention and method 1.2 is lower than that of the conventional method N@44K, and a uniform solidified shell thickness is obtained. By slowing down the casting speed, there is no longer any risk of this happening to round objects, and the casting speed has been improved.

又得られた丸ビレットの机下ム１−指数を測定した。第
４図は各実施例における机下ム１ｍ’ｓ指数を示す図で
ある。横軸は各浸漬ノズルを示し、縦軸は机下ム１ｍ　
Ｏｓ指数を示す。図であきらかのようｋ。Further, the desk M1-index of the obtained round billet was measured. FIG. 4 is a diagram showing the under-desk 1m's index in each example. The horizontal axis shows each immersion nozzle, and the vertical axis shows the height of 1m under the desk.
Indicates the Os index. As is clear from the diagram.

本発明法により鋳込まれた丸ビレツ）　Ｎ０Ｌ２は、従
来法による丸ビレツ）　ＮＯ４４に比ベム１ｍＯｓ系介
在物が浮上除去されて低くなっている。N0L2 is a round billet cast by the method of the present invention) and is lower than NO44 (round billet cast by the conventional method) because 1 mOs-based inclusions are floated and removed.

以上のようにこの発明は丸鋳塁内に溶鋼を渦運動させな
がら注入されるため介在物が溶銅中に深く浸入すること
なく浮上除去されるとと°奄に４．溶鋼流によって凝固
シェルが洗われるようなこともなくなυ、丸ビレットの
生産性は向上し品質も良好なものが得られるのである。As described above, in this invention, since the molten steel is injected into the round cast base while swirling, inclusions can be floated and removed without penetrating deeply into the molten copper. Since the solidified shell is not washed away by the flow of molten steel, the productivity of round billets is improved and good quality can be obtained.

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

第１図はこの発明に用いる浸漬ノズルを示す図、第２図
はこの発明における注入溶鋼の渦流を示す図、第３図は
各実施例における凝固シェル不均一度を示す図、第４図
は各実施例における机下ム１．０゜指数を示す図である
。 １・・・浸漬ノズル本体、２・・・鍔、３−・・吐出孔
、４・・・鋳型、５・・・凝固シェル。 第１図 第２図FIG. 1 is a diagram showing the immersion nozzle used in this invention, FIG. 2 is a diagram showing the vortex flow of injected molten steel in this invention, FIG. 3 is a diagram showing the solidification shell non-uniformity in each example, and FIG. It is a figure which shows the under-desk room 1.0 degree index in each Example. DESCRIPTION OF SYMBOLS 1... Immersion nozzle main body, 2... Flange, 3... Discharge hole, 4... Mold, 5... Solidified shell. Figure 1 Figure 2

Claims (1)

【特許請求の範囲】[Claims] ノズル内径の接線方向に複数個の吐出孔を有する有底の
浸漬ツメ〃を用いて、円形鋳型内の溶鋼流を渦運動させ
ながら注入することを特徴とする丸ビレツＦの連続鋳造
方法。A continuous casting method for a round billet F, characterized in that a molten steel flow in a circular mold is injected while swirling it using a bottomed immersion claw having a plurality of discharge holes in the tangential direction of the inner diameter of the nozzle.