JP2001113347A - Molten metal supplying device and method for continuously casting steel - Google Patents

Molten metal supplying device and method for continuously casting steel

Info

Publication number
JP2001113347A
JP2001113347A JP29659499A JP29659499A JP2001113347A JP 2001113347 A JP2001113347 A JP 2001113347A JP 29659499 A JP29659499 A JP 29659499A JP 29659499 A JP29659499 A JP 29659499A JP 2001113347 A JP2001113347 A JP 2001113347A
Authority
JP
Japan
Prior art keywords
molten steel
ladle nozzle
steel
inert gas
ladle
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.)
Pending
Application number
JP29659499A
Other languages
Japanese (ja)
Inventor
Hideo Mizukami
英夫 水上
Tadashi Hirashiro
正 平城
Seiji Furuhashi
誠治 古橋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to JP29659499A priority Critical patent/JP2001113347A/en
Publication of JP2001113347A publication Critical patent/JP2001113347A/en
Pending legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To provide a continuous casting method, with which an immersion nozzle is not clogged and a cast slab having little non-metallic inclusions and excellent cleanliness and little bubbling defect can be obtained. SOLUTION: A molten metal supplying device is constituted of a ladle nozzle 5 provided with a discharging hole 6 of molten steel at the side surface part of a part whose lower end part is closed and which is dipped into the molten steel, a cylindrical immersion tube 7 whose lower end part is located at the position lower than the lower end part of the ladle nozzle, and provided with a flowing-pass hole 8 for molten steel at the side surface part of a portion dipped into the molten steel and a tundish 1 for pouring the molten steel from the ladle. Further, the device is disposed with the immersion tube whose upper end part is airtightly connected to the ladle nozzle, at the outside of the ladle nozzle and provided with an inert gas blowing hole 4 at a portion where is not dipped into the molten steel in the interval from the ladle nozzle to the immersion tube, and with a gas exhaust hole 9 at a portion where is not dipped into the molten steel, of the immersion tube, and allowing the lower end part of the immersion tube to contact with the bottom part of the tundish. This device is used for the continuous casting of steel.

Description

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

【0001】[0001]

【発明の属する技術分野】本発明は、極低炭素鋼などを
連続鋳造するときに、非金属介在物が少なくて清浄性に
優れ、かつ、気泡性欠陥の少ない鋳片を得ることができ
る給湯装置および鋼の連続鋳造方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply which is capable of obtaining cast slabs having a small amount of non-metallic inclusions, excellent cleanliness, and few bubble defects when continuously casting ultra-low carbon steel or the like. The present invention relates to an apparatus and a method for continuously casting steel.

【0002】[0002]

【従来の技術】表面欠陥が少なく、かつ成形性に優れて
いることが要求される自動車の外装用鋼板には、極低炭
素鋼が用いられる。極低炭素鋼の鋼板の表面欠陥や成形
性には、連続鋳造した鋳片に存在するAl2 3 などの
非金属介在物が影響を及ぼすことが知られている。たと
えば、極低炭素鋼の鋳片を熱間圧延した鋼帯を素材とし
て、冷間圧延した鋼板の表面には、スリバー疵と称する
疵が発生しやすく、その鋼板をさらに冷間でプレスなど
の加工を行うと、割れが発生する場合がある。これらス
リバー疵や冷間加工時の割れは、主にAl2 3 などの
非金属介在物に起因しているので、鋼の清浄性を向上さ
せることは、これらスリバー疵や冷間加工時の割れの発
生の防止に効果的である。
2. Description of the Related Art Ultra-low carbon steel is used as an exterior steel sheet of an automobile which is required to have few surface defects and excellent formability. It is known that non-metallic inclusions such as Al 2 O 3 present in continuously cast slabs have an effect on surface defects and formability of ultra-low carbon steel sheets. For example, using a steel strip obtained by hot-rolling a slab of ultra-low carbon steel as a material, the surface of a cold-rolled steel sheet is susceptible to scratches called sliver flaws, and the steel sheet is further cold-pressed. When processing is performed, cracks may occur. Since these sliver flaws and cracks during cold working are mainly caused by non-metallic inclusions such as Al 2 O 3 , improving the cleanliness of steel requires It is effective in preventing the occurrence of cracks.

【0003】Al2 3 などの非金属介在物、すなわ
ち、溶鋼中のAlの酸化物などは、主に精錬工程で生成
し、また、連続鋳造工程でも溶鋼が酸化されることによ
り生成する。そこで、精錬および連続鋳造の各工程にお
いて、さまざまな鋼の清浄化対策が採られている。とく
に、鋳片を製造する最終工程である連続鋳造工程で、こ
れら溶鋼中の酸化物を除去することは、鋼の清浄性を向
上させる上で効果的であり、タンディッシュにおいて溶
鋼の清浄性を向上させるさまざまな対策が採られてい
る。
[0003] Non-metallic inclusions such as Al 2 O 3 , that is, oxides of Al in molten steel are mainly generated in the refining process, and are also generated in the continuous casting process by oxidizing the molten steel. Therefore, in each of the refining and continuous casting processes, various steel cleaning measures are taken. In particular, removing these oxides in the molten steel in the continuous casting process, which is the final process of manufacturing the slab, is effective in improving the cleanliness of the steel, and the cleanliness of the molten steel in the tundish is improved. Various measures to improve are taken.

【0004】特開平10−235458号公報では、取
鍋ノズルを介して取鍋からタンディッシュ内に溶鋼を注
入するときに、タンディッシュ内の取鍋ノズルの位置と
鋳型への給湯孔との間に、耐火物製のランスを上方から
溶鋼中に浸漬し、このランスから溶鋼中に不活性ガスを
吹き込む方法が提案されている。また、特開平10−2
49499号公報では、取鍋から取鍋ノズルを介してタ
ンディッシュ内に溶鋼を注入するときに、タンディッシ
ュ内の取鍋ノズルの位置と鋳型への給湯孔との間の底部
に配置した堰に備えた不活性ガス供給口から、不活性ガ
スを溶鋼中に吹き込む方法が提案されている。
[0004] In Japanese Patent Application Laid-Open No. Hei 10-235458, when molten steel is poured into a tundish from a ladle through a ladle nozzle, a gap between a position of the ladle nozzle in the tundish and a hot water supply hole to a mold is provided. A method has been proposed in which a lance made of refractory is immersed in molten steel from above, and an inert gas is blown into the molten steel from the lance. Also, JP-A-10-2
No. 49499 discloses that when pouring molten steel from a ladle through a ladle nozzle into a tundish, a weir placed at the bottom between the position of the ladle nozzle in the tundish and the hot water supply hole to the mold is provided. A method has been proposed in which an inert gas is blown into molten steel from an inert gas supply port provided.

【0005】これら特開平10−235458号公報お
よび特開平10−249499号公報で提案された方法
は、いずれもタンディッシュ内の溶鋼中に不活性ガスを
吹き込むことにより発生する不活性ガスの気泡に、溶鋼
中のAlの酸化物などを捕捉させ、これらの気泡をタン
ディッシュ内の溶鋼表面に浮上させる方法である。この
方法では、気泡と共に浮上した溶鋼中の酸化物を、溶鋼
表面に添加したフラックスに吸着させて、溶鋼系外に除
去している。
The methods proposed in Japanese Patent Application Laid-Open Nos. Hei 10-235458 and Hei 10-249499 both dissolve bubbles of inert gas generated by blowing inert gas into molten steel in a tundish. In this method, Al oxides and the like in the molten steel are captured, and these air bubbles float on the surface of the molten steel in the tundish. In this method, the oxides in the molten steel that floated together with the bubbles are adsorbed by the flux added to the surface of the molten steel and removed outside the molten steel system.

【0006】しかし、これらの方法では、吹き込まれた
不活性ガスの気泡の全てが、タンディッシュ内で溶鋼中
から浮上し、除去されるとは限らない。すなわち、不活
性ガスの気泡の一部は、タンディッシュ内の溶鋼中を浮
上しきらず、鋳型内の溶鋼中にまで混入する場合があ
る。鋳型内の溶鋼中にまで混入した不活性ガスの気泡
は、鋳型内の凝固殻に捕捉され、そのまま凝固する。凝
固殻に捕捉された気泡は、鋳片表層部のピンホールと称
する気泡性欠陥となる。気泡性欠陥の存在する鋳片を熱
間圧延した鋼帯を素材として、冷間圧延した鋼板には、
ふくれ疵と称する欠陥が発生する。ふくれ疵とは、鋼板
の内部に閉じこめられた不活性ガスの圧力により、鋼板
の表層部が剥離して膨れた疵である。
[0006] However, in these methods, not all the bubbles of the blown inert gas float up from the molten steel in the tundish and are not always removed. That is, some of the bubbles of the inert gas may not completely float in the molten steel in the tundish and may be mixed into the molten steel in the mold. Inert gas bubbles mixed into the molten steel in the mold are captured by the solidified shell in the mold and solidified as it is. Bubbles trapped in the solidified shell become cellular defects called pinholes in the surface layer of the slab. Using a steel strip obtained by hot-rolling a slab having cellular defects as a material, a cold-rolled steel sheet
A defect called a blister occurs. The blistering flaw is a flaw which swells due to peeling of the surface layer of the steel sheet due to the pressure of the inert gas trapped inside the steel sheet.

【0007】また、これらの方法では、溶鋼中の酸化物
を捕捉し、溶鋼中を浮上してきた不活性ガスの気泡が、
溶鋼と添加されたフラックスの界面に堆積する。界面に
堆積した気泡の一部が、酸化物を捕捉したまま、タンデ
イッシュ内の溶鋼の流れの影響によって、タンディッシ
ュ内の溶鋼中に再び巻き込まれる場合がある。さらに、
溶鋼中に再び巻き込まれた気泡が浸漬ノズルを経て、鋳
型内の溶鋼中にまで混入する場合がある。このとき、酸
化物を捕捉した気泡が、鋳型内の凝固殻に捕捉されるの
で、鋳片表層部に非金属介在物および気泡性欠陥が多く
存在するようになる。表層部に非金属介在物や気泡性欠
陥が多く存在する鋳片を熱間圧延した鋼帯を素材とし
て、冷間圧延した鋼板の表面には、前述するようにスリ
バー疵やふくれ疵が発生しやすい。
[0007] Further, in these methods, oxides in the molten steel are trapped, and bubbles of the inert gas floating in the molten steel are generated.
Deposits at the interface between molten steel and added flux. Some of the air bubbles deposited at the interface may be re-engaged in the molten steel in the tundish due to the influence of the flow of the molten steel in the tundish while retaining the oxide. further,
Bubbles re-engaged in the molten steel may enter the molten steel in the mold through the immersion nozzle. At this time, the air bubbles that have captured the oxide are captured by the solidified shell in the mold, so that many nonmetallic inclusions and cellular defects are present in the surface layer of the slab. Sliver swelling and blistering occur on the surface of the cold-rolled steel sheet, as described above, using a steel strip obtained by hot rolling a slab having many non-metallic inclusions and cellular defects in the surface layer. Cheap.

【0008】さらに、これらの方法では、吹き込まれた
不活性ガスの気泡が、全ての溶鋼中の酸化物を捕捉する
のは困難である。したがって、気泡に捕捉されなかった
溶鋼中の酸化物は浸漬ノズルを通過する。このとき、溶
鋼中の酸化物が浸漬ノズルの内壁に付着しやすく、やが
ては、浸漬ノズルが閉塞して鋳造が困難となる場合があ
る。
Further, in these methods, it is difficult for the bubble of the injected inert gas to capture all the oxides in the molten steel. Therefore, oxides in the molten steel not captured by the bubbles pass through the immersion nozzle. At this time, the oxide in the molten steel tends to adhere to the inner wall of the immersion nozzle, and the immersion nozzle may eventually be closed, making casting difficult.

【0009】そこで、浸漬ノズルの閉塞を防止するため
に、浸漬ノズル内を通過する溶鋼中に不活性ガスを多量
に吹き込み、浸漬ノズルの内壁に酸化物を付着させない
方法が採られるが、浸漬ノズルの詰まりは抑制できるも
のの、不活性ガスの気泡が多量に凝固殻に捕捉されて、
鋳片表層部に気泡性欠陥が発生しやすい。表層部に気泡
性欠陥が多く存在する鋳片を熱間圧延した鋼帯を素材と
して、冷間圧延した鋼板の表面には、前述するようにふ
くれ疵が発生しやすい。
Therefore, in order to prevent blockage of the immersion nozzle, a method is employed in which a large amount of inert gas is blown into molten steel passing through the immersion nozzle so that oxides do not adhere to the inner wall of the immersion nozzle. Clogging can be suppressed, but a large amount of inert gas bubbles are trapped in the solidified shell,
Bubbly defects are likely to occur in the surface layer of the slab. As described above, blisters are likely to occur on the surface of a cold-rolled steel sheet using a steel strip obtained by hot rolling a slab having many cellular defects in the surface layer.

【0010】[0010]

【発明が解決しようとする課題】本発明は、極低炭素鋼
などを鋳造するときに、浸漬ノズルが詰まることなく、
かつ、非金属介在物が少なくて清浄性に優れ、気泡性欠
陥の少ない鋳片を得ることが可能な給湯装置および鋼の
連続鋳造方法を提供することを目的とする。
SUMMARY OF THE INVENTION In the present invention, when casting ultra-low carbon steel or the like, the immersion nozzle is not clogged,
Further, it is an object of the present invention to provide a hot water supply apparatus and a continuous steel casting method capable of obtaining cast slabs having a small amount of nonmetallic inclusions, excellent cleanliness, and a small number of cellular defects.

【0011】[0011]

【課題を解決するための手段】本発明の要旨は、下記
(1)に示す給湯装置および(2)と(3)に示す鋼の
連続鋳造方法にある。 (1)下端部が閉ざされ、溶鋼に浸かる部分の側面部に
溶鋼の吐出孔を備える取鍋ノズルと、下端部が上記取鍋
ノズルの下端部よりも下方にあり、溶鋼に浸かる部分の
側面部に溶鋼の通流孔を備える筒状の浸漬管と、取鍋か
らの溶鋼が注入されるタンディッシュとで構成された給
湯装置であって、上記取鍋ノズルの外側に、上端部が上
記取鍋ノズルに気密に結合された上記浸漬管が配設さ
れ、上記取鍋ノズルから上記浸漬管の間において溶鋼の
浸からない部分に不活性ガス吹き込み口を備え、上記浸
漬管の溶鋼に浸からない部分に排気口を備える給湯装
置。
The gist of the present invention resides in a hot water supply apparatus shown in (1) and a continuous casting method of steel shown in (2) and (3). (1) A ladle nozzle having a lower end closed and having a molten steel discharge hole on a side surface of a part immersed in molten steel, and a side surface having a lower end lower than the lower end of the ladle nozzle and immersed in molten steel. A hot water supply device comprising a cylindrical immersion pipe having a through hole for molten steel in a portion thereof, and a tundish into which molten steel from a ladle is injected, wherein the upper end portion is located outside the ladle nozzle. The immersion pipe air-tightly connected to the ladle nozzle is provided, and an inert gas injection port is provided at a portion where the molten steel is not immersed between the ladle nozzle and the immersion pipe, and is immersed in the molten steel of the immersion pipe. A hot water supply device that has an exhaust port in a part that is not accessible.

【0012】(2)上記(1)に記載の給湯装置を用い
る鋼の連続鋳造方法であって、上記浸漬管の下端部をタ
ンディッシュの底部と接触させ、上記取鍋ノズルの不活
性ガス吹き込み口から上記取鍋ノズル内を通過する溶鋼
中に不活性ガスを吹き込むとともに、上記浸漬管の内面
と上記取鍋ノズルの外面と溶鋼表面とで形成される空間
部に放出された不活性ガスを、上記浸漬管に備える排気
口から大気中に放散させる鋼の連続鋳造方法。
(2) A continuous casting method of steel using the hot water supply apparatus according to (1), wherein a lower end of the dip tube is brought into contact with a bottom of a tundish, and an inert gas is blown into the ladle nozzle. While blowing the inert gas into the molten steel passing through the ladle nozzle from the mouth, the inert gas released into the space formed by the inner surface of the dip tube, the outer surface of the ladle nozzle and the molten steel surface A continuous casting method for steel that is radiated into the atmosphere from an exhaust port provided in the dip tube.

【0013】(3)上記(2)に記載の鋼の連続鋳造方
法において、上記浸漬管の内面と上記取鍋ノズルの外面
と溶鋼表面とで形成される空間部の雰囲気を減圧する鋼
の連続鋳造方法。
(3) The continuous casting method of steel according to (2), wherein the atmosphere in the space formed by the inner surface of the dip tube, the outer surface of the ladle nozzle, and the surface of the molten steel is depressurized. Casting method.

【0014】本発明者らは、前述の本発明の課題を、次
のようにして解決した。 (a)取鍋からタンディッシュ内に溶鋼を注入する役割
の取鍋ノズルの外周に、後述する図1に示すように、取
鍋ノズルよりも大きくて、長い浸漬管を配設する。この
ように取鍋ノズルと浸漬管を配設することにより、浸漬
管の内側と取鍋ノズルの外面と溶鋼表面とで囲まれた空
間部が形成される。取鍋ノズル内を通過する溶鋼中に吹
き込んだ不活性ガスの気泡とともに、取鍋からタンディ
ッシュ内に注入される溶鋼中の酸化物を、この空間部の
溶鋼表面上に浮上させる。
The present inventors have solved the above-mentioned problems of the present invention as follows. (A) As shown in FIG. 1 described below, a dip tube larger and longer than the ladle nozzle is disposed around the ladle nozzle serving to inject molten steel from the ladle into the tundish. By arranging the ladle nozzle and the immersion pipe in this manner, a space surrounded by the inside of the immersion pipe, the outer surface of the ladle nozzle, and the surface of the molten steel is formed. The oxides in the molten steel injected into the tundish from the ladle together with the bubbles of the inert gas blown into the molten steel passing through the ladle nozzle float on the molten steel surface in this space.

【0015】空間部の溶鋼表面上に浮上した酸化物は、
溶鋼の表面張力の作用や溶鋼の流れなどにより、浸漬管
の内壁や取鍋ノズルの外壁に付着し、溶鋼系外に除去さ
れる。また、吹き込んだ不活性ガスを、浸漬管に備えた
排気口から大気中に放散する。
The oxide floating on the surface of the molten steel in the space,
Due to the action of the surface tension of the molten steel, the flow of the molten steel, etc., it adheres to the inner wall of the immersion pipe and the outer wall of the ladle nozzle and is removed outside the molten steel system. Further, the blown inert gas is released into the atmosphere from an exhaust port provided in the immersion tube.

【0016】(b)空間部の雰囲気を減圧することによ
り、取鍋ノズル内を通過する溶鋼中に吹き込んだ不活性
ガスを、さらに効果的に空間部に放出することができ
る。すなわち、不活性ガスの気泡は、溶鋼中を浮上して
溶鋼表面に達した後、溶鋼表面で泡状となる。溶鋼の表
面張力の作用により、この泡状の気泡は破れにくい。こ
のとき、空間部の雰囲気を減圧することにより、泡状の
気泡内部の不活性ガスの内圧と空間部の雰囲気との圧力
に差ができるために、泡状の気泡がより破れやすくな
る。したがって、効果的に不活性ガスを空間部に放出す
ることができる。また、溶鋼中の酸化物も気泡ととも
に、空間部に効果的に浮上するようになるので、溶鋼中
の酸化物を溶鋼系外に除去できる。
(B) By reducing the atmosphere in the space, the inert gas blown into the molten steel passing through the ladle nozzle can be more effectively discharged into the space. That is, the bubble of the inert gas floats in the molten steel, reaches the surface of the molten steel, and then forms a bubble on the surface of the molten steel. Due to the effect of the surface tension of the molten steel, these foamy bubbles are hardly broken. At this time, by reducing the atmosphere in the space, a difference is generated between the internal pressure of the inert gas inside the bubble and the pressure of the atmosphere in the space, so that the bubble is more easily broken. Therefore, the inert gas can be effectively released to the space. Further, the oxides in the molten steel also effectively float in the space together with the bubbles, so that the oxides in the molten steel can be removed outside the molten steel system.

【0017】(c)不活性ガスを空間部に放出させるの
で、不活性ガスの気泡が、浸漬管の外側に出ることは少
ない。したがって、鋳型内の溶鋼中にまで、不活性ガス
の気泡が混入することを抑制できる。さらに、タンディ
ッシュ内で溶鋼中の酸化物が除去されるので、浸漬ノズ
ルを通過する溶鋼中の酸化物は少なくなる。したがっ
て、浸漬ノズルが詰まることもないので、浸漬ノズルを
通過する溶鋼中に不活性ガスを吹き込むこともない。
(C) Since the inert gas is released into the space, bubbles of the inert gas rarely come out of the immersion tube. Therefore, the incorporation of bubbles of the inert gas into the molten steel in the mold can be suppressed. Further, since the oxides in the molten steel are removed in the tundish, the oxides in the molten steel passing through the immersion nozzle are reduced. Therefore, since the immersion nozzle is not clogged, no inert gas is blown into the molten steel passing through the immersion nozzle.

【0018】上述するようにして、浸漬ノズルが詰まる
ことなく、かつ、非金属介在物が少なくて清浄性に優
れ、気泡性欠陥の少ない鋳片を得ることができる。
As described above, it is possible to obtain a cast piece without clogging of the immersion nozzle, with less nonmetallic inclusions, excellent cleanliness, and with few cellular defects.

【0019】なお、たとえ、吹き込まれた不活性ガスの
気泡のごく一部が、空間部に放出されずに、溶鋼ととも
に浸漬管の外に出る場合でも、その量はわずかであり、
後述するように、タンディッシュ内に配置した堰の効果
などにより、タンディッシュ内の溶鋼中を不活性ガスの
気泡が浮上しやすくなるため、鋳型内の溶鋼中にまで不
活性ガスの気泡が混入することを防止できる。
Incidentally, even if a very small part of the bubble of the injected inert gas is not released into the space but goes out of the immersion tube together with the molten steel, the amount is small.
As described later, the inert gas bubbles easily float in the molten steel in the tundish due to the effect of the weir placed in the tundish, etc., and the inert gas bubbles are mixed in the molten steel in the mold. Can be prevented.

【0020】[0020]

【発明の実施の形態】まず、本発明の給湯装置につい
て、以下に説明する。図1は、本発明の給湯装置の例を
示す模式図である。吐出孔6および通流孔8がそれぞれ
1個の例を示す。取鍋2とタンディッシュ1の間に位置
する取鍋ノズル5の外周に浸漬管7を配置する。取鍋ノ
ズルよりも大きく、長い浸漬管の上端部は、取鍋ノズル
に気密になるように結合し、また、浸漬管の下端部をタ
ンディッシュの底部に接触させて配置する。取鍋ノズル
の側面部に備える吐出孔6から流れ出た溶鋼は、浸漬管
内部にしばらくとどまり、その後、浸漬管の側面部に備
える通流孔8から流れ出て、タンディッシュ本体内部に
溜まる。タンディッシュ内の溶鋼19は、鋳型への給湯
孔17および浸漬ノズル20を経て、鋳型18内に鋳造
される。
DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a hot water supply apparatus of the present invention will be described below. FIG. 1 is a schematic diagram showing an example of a hot water supply device of the present invention. An example is shown in which one discharge hole 6 and one flow hole 8 are provided. An immersion pipe 7 is arranged on the outer periphery of the ladle nozzle 5 located between the ladle 2 and the tundish 1. The upper end of the dip tube, which is larger and longer than the ladle nozzle, is hermetically connected to the ladle nozzle and the lower end of the dip tube is placed in contact with the bottom of the tundish. The molten steel flowing out of the discharge hole 6 provided on the side portion of the ladle nozzle stays inside the immersion tube for a while, and then flows out from the flow hole 8 provided on the side portion of the immersion tube and accumulates inside the tundish body. The molten steel 19 in the tundish is cast into a mold 18 through a hot water supply hole 17 to the mold and an immersion nozzle 20.

【0021】取鍋ノズル5とは、タンディッシュ内の溶
鋼に浸かる長さを有するノズルであって、一般にロング
ノズルと称されるものである。下端部が閉ざされた取鍋
ノズル5には、溶鋼に浸かる部分の側面部に溶鋼が通過
する吐出孔6を設ける。この吐出孔のサイズは、鋳型の
サイズや鋳造速度などに応じて決めればよい。吐出孔の
数は、1〜3個がよい。また、吐出角度は、上向きがよ
い。
The ladle nozzle 5 is a nozzle having a length soaked in molten steel in a tundish, and is generally called a long nozzle. The ladle nozzle 5 having a closed lower end is provided with a discharge hole 6 through which the molten steel passes on a side surface portion of a portion immersed in the molten steel. The size of the discharge hole may be determined according to the size of the mold, the casting speed, and the like. The number of discharge holes is preferably 1 to 3. Further, the discharge angle is preferably upward.

【0022】浸漬管7は、上端部が取鍋ノズルに気密に
結合させた筒状の浸漬管とする。気密に結合した状態と
は、空間部の雰囲気を減圧する場合でも、浸漬管の上端
部と取鍋ノズルとの結合部分から、大気などが空間部内
に侵入しない程度の状態を意味する。また、浸漬管の下
端部は、溶鋼が多く流れない程度に、タンディッシュの
底部と接触させる。浸漬管の下端部は、開口した形状で
もよいし、底板などで閉ざされた形状でも構わない。さ
らに、浸漬管の溶鋼に浸かる部分の側面部には、溶鋼が
通過する通流孔8を設ける。この通流孔のサイズは、鋳
型のサイズや鋳造速度などに応じて決めればよい。通流
孔の数は、取鍋ノズルの吐出孔の数の1〜3個に対応し
て、それぞれ1〜3個とするのがよい。また、通流孔の
吐出角度は、とくにこだわらない。さらに、浸漬管の上
部で溶鋼に浸からない部分には、排気口9を配置する。
図1では、排気口9に、減圧装置用の取り付け口15を
装着している状況を示す。この減圧装置用の取り付け口
の後段には、減圧装置14を配置する。浸漬管の水平断
面形状は、円形でも矩形でもよく、とくに限定しない。
The immersion pipe 7 is a cylindrical immersion pipe whose upper end is air-tightly connected to a ladle nozzle. The air-tightly coupled state means a state in which the atmosphere or the like does not enter the space from the connection between the upper end of the immersion tube and the ladle nozzle even when the atmosphere in the space is depressurized. Also, the lower end of the immersion tube is brought into contact with the bottom of the tundish to such an extent that the molten steel does not flow much. The lower end of the dip tube may have an open shape or a shape closed by a bottom plate or the like. Further, a through hole 8 through which the molten steel passes is provided on a side surface of a portion of the immersion pipe that is immersed in the molten steel. The size of the through hole may be determined according to the size of the mold, the casting speed, and the like. The number of through holes is preferably 1 to 3 corresponding to 1 to 3 discharge holes of the ladle nozzle. Further, the discharge angle of the through hole is not particularly limited. Further, an exhaust port 9 is provided in a portion of the upper part of the immersion pipe that is not immersed in the molten steel.
FIG. 1 shows a state in which the exhaust port 9 is provided with a mounting port 15 for a decompression device. The decompression device 14 is arranged downstream of the mounting port for the decompression device. The horizontal cross-sectional shape of the immersion tube may be circular or rectangular, and is not particularly limited.

【0023】取鍋ノズルおよび浸漬管の材質は、溶鋼や
タンディッシュ内のフラックスなどに対する溶損が少な
いことから、浸漬ノズルに用いられるアルミナ・グラフ
ァイトの耐火物がよい。
The material of the ladle nozzle and the immersion pipe is preferably an alumina-graphite refractory used for the immersion nozzle, since it is hardly melted by molten steel or flux in the tundish.

【0024】図2は、タンディッシュなどの上面図であ
る。図2(a)は、図1におけるA1−A2線の断面
図、また、図2(b)は、図1におけるB1−B2線の
断面図をそれぞれ示す。
FIG. 2 is a top view of a tundish or the like. 2A is a sectional view taken along line A1-A2 in FIG. 1, and FIG. 2B is a sectional view taken along line B1-B2 in FIG.

【0025】取鍋ノズルの吐出孔と浸漬管の通流孔の高
さ方向での位置関係は、できるだけ離した方がよい。そ
れぞれ溶鋼に浸かる範囲の領域で、吐出孔6は取鍋ノズ
ル5の下部、通流孔8は浸漬管7の上部がよい。また、
取鍋ノズルの吐出孔と浸漬管の通流孔の水平方向での位
置関係は、次のようにするとよい。すなわち、水平方向
でのお互いの角度で表現すれば、それぞれ1個の孔のと
き、図2に示すように、お互いの角度が180°である
ようにするのがよい。それぞれ2個の孔のとき、2個の
吐出孔同士または2個の通流孔同士の角度が、それぞれ
180°であり、吐出孔と通流孔との間の角度が90°
であればよい。それぞれ3個の孔のときには、同様に、
吐出孔同士または通流孔同士の角度が、それぞれ120
°であり、吐出孔と通流孔との間の角度が60°であれ
ばよい。取鍋ノズルの吐出孔から流れ出た溶鋼が浸漬管
の内部にとどまりやすくなるからである。
The positional relationship between the discharge hole of the ladle nozzle and the flow hole of the immersion pipe in the height direction should be as far as possible. The discharge hole 6 is preferably located below the ladle nozzle 5 and the flow hole 8 is preferably located above the immersion pipe 7 in the range of the area immersed in the molten steel. Also,
The horizontal positional relationship between the discharge hole of the ladle nozzle and the flow hole of the immersion pipe may be as follows. In other words, when expressed in terms of the angle between each other in the horizontal direction, it is preferable that each of the holes has a single angle of 180 ° as shown in FIG. 2 for one hole. In the case of two holes respectively, the angle between two discharge holes or two flow holes is 180 °, and the angle between the discharge hole and the flow hole is 90 °.
Should be fine. Similarly, when there are three holes,
The angle between the discharge holes or the flow holes is 120
° and the angle between the discharge hole and the flow hole may be 60 °. This is because the molten steel flowing out from the discharge hole of the ladle nozzle tends to stay inside the immersion pipe.

【0026】取鍋ノズル外側の側面部と浸漬管内側の側
面部との間の距離は、50〜200mmにするのがよ
い。50mm未満では、取鍋ノズル外面と浸漬管内面と
溶鋼表面とで形成される空間部の容積が小さくなり、不
活性ガスが空間部の排気口などから抜けきらず、不活性
ガスの気泡が浸漬管の外側のタンディッシュ内の溶鋼中
を浮上しやすくなる。また、200mmを超える場合に
は、浸漬管が大きくなりすぎて、取鍋およびタンディッ
シュへの取り付け作業が困難となり、また、操業コスト
が増大する。
The distance between the side portion outside the ladle nozzle and the side portion inside the dip tube is preferably 50 to 200 mm. If the diameter is less than 50 mm, the volume of the space formed by the outer surface of the ladle nozzle, the inner surface of the immersion pipe, and the surface of the molten steel becomes small, and the inert gas cannot escape from the exhaust port of the space, etc. It easily floats in the molten steel in the tundish outside. On the other hand, if it exceeds 200 mm, the dip tube becomes too large, making it difficult to attach it to a ladle and a tundish, and increases operating costs.

【0027】図1に示すように、取鍋2と取鍋ノズル5
との接続部には、通過する溶鋼19の量を調整するスラ
イデイングゲート3および取鍋ノズル内を通過する溶鋼
中に不活性ガスを吹き込むための不活性ガス吹き込み口
4を配置するのがよい。ガス吹き込み口4の後段には、
吹き込む不活性ガスの量と圧力を調整するための不活性
ガス吹き込み量調整装置12を配置する。
As shown in FIG. 1, a ladle 2 and a ladle nozzle 5
It is preferable to arrange a sliding gate 3 for adjusting the amount of molten steel 19 passing therethrough and an inert gas injection port 4 for blowing an inert gas into the molten steel passing through the ladle nozzle. . After the gas inlet 4,
An inert gas blowing amount adjusting device 12 for adjusting the amount and pressure of the inert gas to be blown is disposed.

【0028】ガス吹き込み口4には、内径が0.1〜1
mmの鋼製の管を複数個埋め込んだ耐火物のノズルや多
孔質耐火物を用いればよい。また、吹き込むガスには、
Arなどの不活性ガスを用いるのがよい。
The gas inlet 4 has an inner diameter of 0.1 to 1
A refractory nozzle or a porous refractory in which a plurality of mm steel tubes are embedded may be used. Also, the gas to be blown
It is preferable to use an inert gas such as Ar.

【0029】図1に示す例では、ガス吹き込み口4を、
スライデイングゲート3の下方で、取鍋ノズル5の上部
に備える例を示すが、スライデイングゲート内に備えて
もよいし、また、取鍋の上ノズル(図示していない)内
に備えてもよい。
In the example shown in FIG. 1, the gas inlet 4 is
An example is shown below the sliding gate 3 above the ladle nozzle 5, but it may be provided inside the sliding gate or inside the upper nozzle (not shown) of the ladle. Good.

【0030】タンディッシュの底部で取鍋ノズル5と鋳
型への給湯孔17との間の位置には、下部に溶鋼の通流
孔を開けた堰10を配置するのがよい。
At the bottom of the tundish between the ladle nozzle 5 and the hot water supply hole 17 for the mold, a weir 10 having a flow passage for molten steel at the bottom is preferably arranged.

【0031】次に、本発明の方法について、以下に具体
的に説明する。連続鋳造の開始時には、浸漬管7内に溶
鋼が注入されると、浸漬管内で溶鋼の湯面が徐々に上昇
する。その後、さらに溶鋼の湯面が上昇すると、溶鋼が
浸漬管の通流孔8からタンディッシュ1内に供給され
る。タンディッシュ内に供給された溶鋼は、堰10、鋳
型への給湯孔17、浸漬ノズル20などを経て、鋳型1
8内に注入される。
Next, the method of the present invention will be specifically described below. At the start of continuous casting, when molten steel is injected into the immersion pipe 7, the molten steel surface gradually rises in the immersion pipe. Thereafter, when the molten steel surface rises further, the molten steel is supplied into the tundish 1 from the through holes 8 of the dip tube. The molten steel supplied into the tundish passes through a weir 10, a hot water supply hole 17 to the mold, an immersion nozzle 20, and the like.
8 is injected.

【0032】溶鋼が浸漬管7の側面部に備えた通流孔8
の上方に達し、タンディッシュ内に溶鋼の湯面が形成さ
れてから、溶鋼表面にフラックス11を添加し、溶鋼と
空気との接触を遮断して、溶鋼が酸化されるのを防止す
るのがよい。さらに、溶鋼の空気による酸化を少なくす
るために、タンディッシュの蓋21と溶鋼とで形成され
る部分に、不活性ガスを吹き込むのがよい。
The molten steel is provided with a through hole 8 provided on the side of the immersion pipe 7.
After the molten steel surface is formed in the tundish, flux 11 is added to the molten steel surface to cut off contact between the molten steel and air to prevent the molten steel from being oxidized. Good. Further, in order to reduce oxidation of the molten steel by air, it is preferable to blow an inert gas into a portion formed by the lid 21 of the tundish and the molten steel.

【0033】取鍋ノズル5内を通過する溶鋼中に不活性
ガスを吹き込むとき、不活性ガスの気泡13は、浸漬管
内面と取鍋ノズル外面と溶鋼表面とで形成される空間部
16に放出される。空間部に放出された不活性ガスは、
浸漬管7に備える排気口9から大気中に放散させる。取
鍋ノズル内を通過する溶鋼中に不活性ガスを吹き込み始
めるのは、連続鋳造の開始時に、浸漬管の通流孔8に溶
鋼の湯面が達したときからでよい。
When the inert gas is blown into the molten steel passing through the ladle nozzle 5, bubbles 13 of the inert gas are discharged into a space 16 formed by the inner surface of the immersion tube, the outer surface of the ladle nozzle, and the surface of the molten steel. Is done. The inert gas released into the space is
The gas is radiated into the atmosphere from an exhaust port 9 provided in the immersion pipe 7. The start of blowing the inert gas into the molten steel passing through the ladle nozzle may be started when the molten steel surface reaches the through hole 8 of the immersion pipe at the start of continuous casting.

【0034】取鍋ノズルの吐出孔6と浸漬管の通流孔8
の水平方向での位置関係を、前述するように、特定の角
度を持つようにすることなどにより、取鍋ノズルの吐出
孔から流れ出た溶鋼が浸漬管7の内部にとどまりやすく
なる。そのため、吹き込まれた不活性ガスの多くは、空
間部16に放出されやすくなる。空間部に放出された不
活性ガスは、浸漬管の排気口から大気中に放散されるの
で、引き続き溶鋼中の不活性ガスは空間部に放出され
る。
The discharge hole 6 of the ladle nozzle and the flow hole 8 of the immersion tube
As described above, by setting the positional relationship in the horizontal direction to have a specific angle, for example, the molten steel flowing out from the discharge hole of the ladle nozzle easily stays inside the immersion pipe 7. Therefore, most of the injected inert gas is easily released into the space 16. Since the inert gas released into the space is radiated into the atmosphere from the exhaust port of the immersion pipe, the inert gas in the molten steel is continuously released into the space.

【0035】図1に示すように、減圧装置14を作動さ
せることにより、排気口9に装着した減圧装置用の取り
付け口15を経由して、空間部16の雰囲気を排気し
て、減圧するのが望ましい。空間部の雰囲気を排気し
て、減圧することにより、より効果的に不活性ガスを空
間部に放出することができる理由は、前述のとおりで、
溶鋼中を浮上して溶鋼表面に達した不活性ガスの泡状の
気泡が、雰囲気の減圧の効果で破れやすくなるためであ
る。
As shown in FIG. 1, by operating the pressure reducing device 14, the atmosphere in the space 16 is evacuated through the mounting port 15 for the pressure reducing device mounted on the exhaust port 9 to reduce the pressure. Is desirable. The reason why the inert gas can be more effectively released to the space by exhausting the atmosphere in the space and reducing the pressure is as described above.
This is because the bubble of the inert gas which floats in the molten steel and reaches the surface of the molten steel is easily broken by the effect of the reduced pressure of the atmosphere.

【0036】減圧するときの圧力は、空間部の大きさや
形状などで決めればよく、0.5気圧以上大気圧未満と
するのが望ましい。0.5気圧未満の圧力では、溶鋼を
高さが約700mm上昇するので、ほぼ全ての空間部に
溶鋼が充満するようになったり、排気口に溶鋼が詰まっ
て、減圧できなくなるからである。
The pressure at which the pressure is reduced may be determined according to the size and shape of the space, and is preferably 0.5 atm or more and less than atmospheric pressure. At a pressure of less than 0.5 atm, the height of the molten steel rises by about 700 mm, so that almost all the space is filled with the molten steel, or the molten steel is clogged in the exhaust port, and the pressure cannot be reduced.

【0037】空間部に向かって浮上する不活性ガスの気
泡には、溶鋼中の酸化物が捕捉されているので、気泡と
ともに浮上した溶鋼中の酸化物は、空間部を形成する浸
漬管内側の側面部や取鍋ノズル外側の側面部などに付着
する。そのため、溶鋼中からAlの酸化物などを除去で
きる。
Since the oxides in the molten steel are trapped in the bubbles of the inert gas that floats toward the space, the oxides in the molten steel that floated together with the bubbles are generated inside the immersion tube that forms the space. It adheres to the side and the outside of the ladle nozzle. Therefore, oxides of Al and the like can be removed from the molten steel.

【0038】[0038]

【実施例】垂直曲げ型試験連続鋳造機を用いて、厚み1
50mm、幅800mmの矩形の鋳片を、2.0m/分
の速度で鋳造した。C含有率が約0.002質量%の極
低炭素鋼を用いた。各試験は約80tonである。
EXAMPLE Using a vertical bending type test continuous casting machine, a thickness of 1 was used.
A rectangular slab having a width of 50 mm and a width of 800 mm was cast at a speed of 2.0 m / min. Ultra-low carbon steel having a C content of about 0.002 mass% was used. Each test is about 80 tons.

【0039】本発明例の試験には、図1に示す装置構成
の給湯装置を用いた。また、比較例の試験には、取鍋ノ
ズルの外周に浸漬管を配置しない給湯装置を用いた。タ
ンディッシュの容量は15tonで、内法サイズは、幅
1000mm、高さ800mm、長さ2500mmであ
る。本発明例および比較例の試験ともに、タンディッシ
ュの底部には、鋳型への給湯孔との距離1000mmの
位置に、高さ800mmの堰を備えた。堰の下部には、
縦80mm、横100mmの矩形の溶鋼の供給口を1個
配置した。
In the test of the present invention, a hot water supply apparatus having the configuration shown in FIG. 1 was used. In addition, in the test of the comparative example, a hot water supply device in which no immersion pipe was arranged on the outer periphery of the ladle nozzle was used. The capacity of the tundish is 15 tons, and the inner size is 1000 mm in width, 800 mm in height, and 2500 mm in length. In both the tests of the present invention example and the comparative example, the bottom of the tundish was provided with a weir having a height of 800 mm at a distance of 1000 mm from the hot water supply hole to the mold. At the bottom of the weir,
One rectangular molten steel supply port having a length of 80 mm and a width of 100 mm was arranged.

【0040】取鍋の取鍋ノズルは、本発明例および比較
例の試験ともに、外径100mm、内径80mm、長さ
1000mmでアルミナグラファイト製とした。取鍋ノ
ズルの吐出孔は1個で、大きさは縦80mm、横60m
mの長方形とし、上向き20°の角度とした。
The ladle nozzle of the ladle was made of alumina graphite having an outer diameter of 100 mm, an inner diameter of 80 mm, and a length of 1000 mm in both the tests of the present invention and the comparative example. The ladle nozzle has one discharge hole, 80 mm long and 60 m wide.
m and a 20 ° upward angle.

【0041】本発明例の試験に用いた浸漬管は、外径5
60mm、内径500mm、長さ1000mmでアルミ
ナグラファイト製とした。浸漬管の通流孔も1個とし、
大きさは吐出孔と同じとし、角度は水平とした。また、
吐出孔と通流孔の水平方向の位置関係は、図2に示すと
おりとした。
The dip tube used in the test of the present invention had an outer diameter of 5 mm.
It was made of alumina graphite having a size of 60 mm, an inner diameter of 500 mm, and a length of 1000 mm. The immersion pipe has one through hole,
The size was the same as the ejection hole, and the angle was horizontal. Also,
The horizontal positional relationship between the discharge hole and the flow hole was as shown in FIG.

【0042】本発明例および比較例の各試験ともに、内
径が0.5mmの鋼製の管を20個埋め込んだ耐火物の
不活性ガス吹き込み口を、取鍋ノズルの上部に配置し、
10Nリットル/分の流量でArガスを吹き込んだ。
In each of the tests of the present invention example and the comparative example, a refractory inert gas injection port in which 20 steel pipes having an inner diameter of 0.5 mm were embedded was arranged above the ladle nozzle.
Ar gas was blown in at a flow rate of 10 Nl / min.

【0043】浸漬管の上部で溶鋼の浸からない部分に直
径50mmの排気口を配置した。空間部の雰囲気を減圧
するときには、この排気口に減圧装置用の取り付け口を
備えた。また、減圧装置には、ロータリーポンプ式で、
排気能力は50リットル/分、可能な到達真空度は0.
01気圧の性能の装置を用いた。
An exhaust port having a diameter of 50 mm was arranged in a portion of the upper part of the dip tube where the molten steel was not immersed. When the atmosphere in the space was depressurized, the exhaust port was provided with a mounting port for a decompression device. Also, the decompression device is a rotary pump type,
The pumping capacity is 50 liters / minute, and the ultimate vacuum that can be achieved is 0.
An apparatus having a performance of 01 atm was used.

【0044】連続鋳造の開始時、浸漬管の通流孔に溶鋼
の湯面が達したときから、取鍋ノズル内を通過する溶鋼
中に不活性ガスを吹き込み始めた。また、溶鋼が浸漬管
の側面部に備えた通流孔の上方に達し、タンディッシュ
内に溶鋼の湯面が形成されてから、溶鋼表面にCaO系
のフラックスを添加した。
At the start of the continuous casting, an inert gas was started to be blown into the molten steel passing through the ladle nozzle from when the molten steel surface reached the through hole of the dip tube. Also, after the molten steel reached the upper side of the through hole provided in the side surface of the immersion pipe and the molten steel surface was formed in the tundish, a CaO-based flux was added to the molten steel surface.

【0045】各試験の各ヒートにおいて、鋳造方向に1
mの長さの鋳片サンプルを採取し、得られた鋳片サンプ
ルの表層10mmを除いた位置から1kgの鋼を採取
し、電解法(スライム抽出法)により非金属介在物を抽
出し、その鋳造ヒートの非金属介在物の重量とした。比
較例の試験結果を100として、本発明例の試験結果を
指数で評価した。
In each heat of each test, 1
A slab sample having a length of m was collected, and 1 kg of steel was collected from a position except for a surface layer of 10 mm of the obtained slab sample, and nonmetallic inclusions were extracted by an electrolytic method (slime extraction method). The weight of the non-metallic inclusions in the casting heat. With the test result of the comparative example as 100, the test result of the present invention example was evaluated by an index.

【0046】また、各試験で得られた鋳片から、厚さ約
2mmの熱間圧延鋼帯に圧延し、コイルに巻き取った。
このコイルを素材として、厚さ0.7mmのコイル製品
に冷間圧延し、このコイル製品の表面欠陥発生率を調査
した。ここで、コイル製品の表面欠陥発生率とは、鋳片
の非金属介在物や気泡性欠陥が原因であるコイル製品の
スリバー疵やふくれ疵の表面欠陥の発生率のことで、コ
イル製品の重量のうち、表面欠陥の発生している部分の
重量の比率のことである。比較例の試験結果を100と
して、本発明例の試験結果を指数で評価した。
The slab obtained in each test was rolled into a hot-rolled steel strip having a thickness of about 2 mm and wound around a coil.
Using this coil as a raw material, it was cold-rolled into a coil product having a thickness of 0.7 mm, and the occurrence rate of surface defects of this coil product was investigated. Here, the surface defect occurrence rate of a coil product refers to the incidence rate of surface defects such as sliver flaws and blistering flaws of the coil product due to nonmetallic inclusions or foamy defects in the cast slab. Is the weight ratio of the portion where the surface defect occurs. With the test result of the comparative example as 100, the test result of the present invention example was evaluated by an index.

【0047】なお、気泡の直径を調べるために、浸漬管
を設けずにタンディッシュ内に溶鋼を注入し、取鍋ノズ
ル近傍に100mm角で50mm厚みの銅ブロックを5
秒間浸漬させ、気泡を捕捉させた凝固殻を採取した。こ
の凝固殻の断面を観察し気泡の直径を測定した結果、9
0%以上の気泡の直径が約1mmであることが確認され
た。直径1mmの気泡の浮上速度はストークスの法則か
ら予測することができ、この直径の場合は約20cm/
秒である。また、本試験の鋳造条件において、浸漬管内
における溶鋼の滞留時間は約30秒であることと、浸漬
管内の溶鋼深さが600mmであることから滞留時間内
に気泡の浮上がほぼ完了することが予測できる。さら
に、浸漬管の通流孔を通過する溶鋼の流速は約12cm
/秒であり、気泡の浮上速度の方が大きいことから、気
泡が溶鋼とともに通流孔を通過して浸漬管外へ出る可能
性はほとんどないことも予測できる。表1に各試験条件
および各試験結果を示す。
In order to check the diameter of bubbles, molten steel was poured into a tundish without providing a dip tube, and a copper block of 100 mm square and 50 mm thick was placed near the ladle nozzle.
The sample was immersed for 2 seconds, and the solidified shell in which bubbles were captured was collected. As a result of observing the cross section of the solidified shell and measuring the diameter of the bubble, 9
It was confirmed that the diameter of 0% or more bubbles was about 1 mm. The flying speed of a bubble having a diameter of 1 mm can be predicted from Stokes' law, and in the case of this diameter, about 20 cm /
Seconds. In addition, under the casting conditions of this test, the residence time of the molten steel in the dip tube is about 30 seconds, and since the molten steel depth in the dip tube is 600 mm, the floating of bubbles is almost completed within the residence time. Can be predicted. Furthermore, the flow velocity of the molten steel passing through the through hole of the dip tube is about 12 cm.
/ Sec, and the rising speed of the bubbles is higher, so it can be predicted that there is almost no possibility that the bubbles pass through the through holes together with the molten steel and go out of the immersion tube. Table 1 shows each test condition and each test result.

【0048】[0048]

【表1】 [Table 1]

【0049】取鍋ノズルの外周に浸漬管を配置した給湯
装置を用いた本発明例の試験No.1では、空間部の雰
囲気を減圧しなかったが、鋳片の非金属介在物の発生指
数は、後述する比較例の試験結果を100とするとき、
指数10であり、良好な結果であった。また、コイル製
品の表面欠陥の発生指数も比較例の試験結果を100と
するとき、指数20であり良好な結果であった。
Test No. 1 of the present invention example using a hot water supply apparatus in which a dip tube is arranged on the outer periphery of a ladle nozzle. In 1, the pressure in the atmosphere in the space was not reduced, but the index of occurrence of nonmetallic inclusions in the slab was 100 when the test result of the comparative example described later was 100.
The index was 10, which was a good result. The index of occurrence of surface defects of the coil product was 20 when the test result of the comparative example was set to 100, which was a good result.

【0050】取鍋ノズルの外周に浸漬管を配置し、取鍋
ノズル内を通過する溶鋼にArの不活性ガスを吹き込
み、溶鋼中の酸化物を空間部に集めた効果である。ま
た、不活性ガスの気泡を空間部に向かって浮上させて、
鋳型内の溶鋼中にまで侵入させなかった効果である。ま
た、鋳造中にタンディッシュ内の溶鋼表面に添加したフ
ラックスを観察したが、溶鋼表面が全てフラックスに覆
われて、フラックスの表面は静かであった。
This is an effect that an immersion tube is arranged around the ladle nozzle, an inert gas of Ar is blown into the molten steel passing through the ladle nozzle, and oxides in the molten steel are collected in the space. In addition, air bubbles of inert gas are levitated toward the space,
This is an effect of not penetrating into molten steel in the mold. The flux added to the surface of the molten steel in the tundish during casting was observed, but the surface of the molten steel was entirely covered with the flux, and the surface of the flux was quiet.

【0051】取鍋ノズルの外周に浸漬管を配置した給湯
装置を用いた本発明例の試験No.2では、空間部の雰
囲気を減圧した。減圧するときの圧力は0.7気圧とし
た。鋳片の非金属介在物の発生指数は指数5で、また、
コイル製品の気泡性欠陥の発生指数も指数3で、試験N
o.1よりも良好な結果であった。
Test No. 1 of the present invention example using a hot water supply device in which a dip tube is arranged on the outer periphery of a ladle nozzle. In 2, the pressure in the space was reduced. The pressure at which the pressure was reduced was 0.7 atm. The index of occurrence of nonmetallic inclusions in the slab is index 5, and
The index of occurrence of bubble defects in coil products is also index 3, and the test N
o. The result was better than 1.

【0052】試験No.1の試験結果よりも良好であっ
たのは、空間部の雰囲気を減圧した効果である。減圧す
ることにより、不活性ガスの気泡を、より効果的に空間
部に向かって浮上できたためである。また、鋳造中にタ
ンディッシュ内の溶鋼表面に添加したフラックスを観察
したが、溶鋼表面が全てフラックスに覆われて、フラッ
クスの表面は静かであった。
Test No. What was better than the test result of No. 1 was the effect of reducing the atmosphere in the space. This is because by reducing the pressure, bubbles of the inert gas can be more effectively floated toward the space. The flux added to the surface of the molten steel in the tundish during casting was observed, but the surface of the molten steel was entirely covered with the flux, and the surface of the flux was quiet.

【0053】取鍋ノズルの外周に浸漬管を配置しない給
湯装置を用いた比較例の試験No.3では、吹き込んだ
不活性ガスの気泡の一部が鋳型内の溶鋼中に混入したた
め、鋳片表層部に気泡性欠陥や非金属介在物が多く発生
し、コイル製品の表面にも、スリバー疵やふくれ疵が多
く発生した。また、鋳造中にタンディッシュ内の溶鋼表
面に添加したフラックスを観察したが、溶鋼表面の一部
分がフラックスに覆われなくて、また、溶鋼表面に不活
性ガスの気泡が浮上するのが観察できた。
Test No. 5 of the comparative example using a hot water supply apparatus in which no immersion pipe is arranged on the outer periphery of the ladle nozzle. In No. 3, since some of the bubbles of the injected inert gas were mixed into the molten steel in the mold, a lot of bubble defects and nonmetallic inclusions were generated on the surface layer of the slab, and sliver flaws were also found on the surface of the coil product. Many bulges occurred. Also, the flux added to the molten steel surface in the tundish during casting was observed, but a portion of the molten steel surface was not covered by the flux, and bubbles of inert gas were observed to float on the molten steel surface. .

【0054】[0054]

【発明の効果】本発明の給湯装置および鋼の連続鋳造方
法の適用により、極低炭素鋼などを鋳造する際に、浸漬
ノズルが詰まることなく、かつ、非金属介在物が少なく
て清浄性に優れ、気泡性欠陥の少ない鋳片を得ることが
できる。
By applying the hot water supply apparatus and the continuous casting method of steel according to the present invention, when casting ultra-low carbon steel or the like, the immersion nozzle is not clogged and the non-metallic inclusions are reduced and the cleanliness is improved. It is possible to obtain a cast piece which is excellent and has few cellular defects.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の給湯装置の例を示す模式図である。FIG. 1 is a schematic view showing an example of a hot water supply device of the present invention.

【図2】タンディッシュなどの上面図である。FIG. 2 is a top view of a tundish or the like.

【符号の説明】[Explanation of symbols]

1:タンディッシュ 2:取鍋 3:スライディングゲート 4:不活性ガス吹き
込み口 5:取鍋ノズル 6:吐出孔 7:浸漬管 8:通流孔 9:排気口 10:堰 11:フラックス 12:不活性ガス吹
き込み量調整装置 13:不活性ガスの気泡 14:減圧装置 15:減圧装置用の取り付け口 16:空間部 17:鋳型への給湯孔 18:鋳型 19:溶鋼 20:浸漬ノズル 21:タンディッシュの蓋
1: Tundish 2: Ladle 3: Sliding gate 4: Inert gas blowing port 5: Ladle nozzle 6: Discharge hole 7: Immersion tube 8: Flow hole 9: Exhaust port 10: Weir 11: Flux 12: Not Active gas blowing amount adjusting device 13: Inert gas bubble 14: Decompression device 15: Installation port for decompression device 16: Space 17: Hot water supply hole to mold 18: Mold 19: Molten steel 20: Immersion nozzle 21: Tundish Lid

フロントページの続き (51)Int.Cl.7 識別記号 FI テーマコート゛(参考) C21C 7/072 C21C 7/072 J C22B 9/05 C22B 9/05 (72)発明者 古橋 誠治 大阪府大阪市中央区北浜4丁目5番33号住 友金属工業株式会社内 Fターム(参考) 4E004 HA00 4K001 AA10 GA18 GB02 4K013 AA07 AA09 BA14 CA02 CA21 CA25 CE05 Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat II (reference) C21C 7/072 C21C 7/072 J C22B 9/05 C22B 9/05 (72) Inventor Seiji Furuhashi Chuo-ku, Osaka-shi, Osaka Kitahama 4-5-33 Sumitomo Metal Industries Co., Ltd. F-term (reference) 4E004 HA00 4K001 AA10 GA18 GB02 4K013 AA07 AA09 BA14 CA02 CA21 CA25 CE05

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】下端部が閉ざされ、溶鋼に浸かる部分の側
面部に溶鋼の吐出孔を備える取鍋ノズルと、下端部が上
記取鍋ノズルの下端部よりも下方にあり、溶鋼に浸かる
部分の側面部に溶鋼の通流孔を備える筒状の浸漬管と、
取鍋からの溶鋼が注入されるタンディッシュとで構成さ
れた給湯装置であって、上記取鍋ノズルの外側に、上端
部が上記取鍋ノズルに気密に結合された上記浸漬管が配
設され、上記取鍋ノズルから上記浸漬管の間において溶
鋼の浸からない部分に不活性ガス吹き込み口を備え、上
記浸漬管の溶鋼に浸からない部分に排気口を備えること
を特徴とする給湯装置。
1. A ladle nozzle having a lower end closed and having a molten steel discharge hole on a side surface of a part immersed in molten steel, and a part whose lower end is lower than the lower end of the ladle nozzle and immersed in molten steel. A cylindrical immersion pipe provided with a through hole for molten steel on the side surface of
A hot water supply device comprising a tundish into which molten steel from a ladle is injected, wherein the dip tube having an upper end hermetically coupled to the ladle nozzle is disposed outside the ladle nozzle. A hot water supply apparatus comprising: an inert gas injection port at a portion where the molten steel is not immersed between the ladle nozzle and the immersion pipe; and an exhaust port at a portion of the immersion pipe that is not immersed in the molten steel.
【請求項2】請求項1に記載の給湯装置を用いる鋼の連
続鋳造方法であって、上記浸漬管の下端部をタンディッ
シュの底部と接触させ、上記取鍋ノズルの不活性ガス吹
き込み口から上記取鍋ノズル内を通過する溶鋼中に不活
性ガスを吹き込むとともに、上記浸漬管の内面と上記取
鍋ノズルの外面と溶鋼表面とで形成される空間部に放出
された不活性ガスを、上記浸漬管に備える排気口から大
気中に放散させることを特徴とする鋼の連続鋳造方法。
2. A continuous casting method for steel using the hot water supply apparatus according to claim 1, wherein a lower end of the dip tube is brought into contact with a bottom of a tundish and the inert gas is blown from an inert gas inlet of the ladle nozzle. While blowing the inert gas into the molten steel passing through the ladle nozzle, the inert gas released into the space formed by the inner surface of the dip tube, the outer surface of the ladle nozzle and the surface of the molten steel, A continuous casting method for steel, wherein the steel is radiated into the atmosphere from an exhaust port provided in a dip tube.
【請求項3】請求項2に記載の鋼の連続鋳造方法におい
て、上記浸漬管の内面と上記取鍋ノズルの外面と溶鋼表
面とで形成される空間部の雰囲気を減圧することを特徴
とする鋼の連続鋳造方法。
3. The continuous casting method for steel according to claim 2, wherein the atmosphere in a space formed by the inner surface of the immersion tube, the outer surface of the ladle nozzle and the surface of the molten steel is reduced in pressure. Continuous casting method for steel.
JP29659499A 1999-10-19 1999-10-19 Molten metal supplying device and method for continuously casting steel Pending JP2001113347A (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
JP29659499A JP2001113347A (en) 1999-10-19 1999-10-19 Molten metal supplying device and method for continuously casting steel

Publications (1)

Publication Number Publication Date
JP2001113347A true JP2001113347A (en) 2001-04-24

Family

ID=17835577

Family Applications (1)

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Country Link
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007044731A (en) * 2005-08-10 2007-02-22 Sumitomo Metal Ind Ltd Pouring tube and pouring method of molten metal
US8030082B2 (en) 2006-01-13 2011-10-04 Honeywell International Inc. Liquid-particle analysis of metal materials
CN104525929A (en) * 2014-12-18 2015-04-22 东北大学 Method for controlling steel ladle tapping slag by blowing argon gas to annular steel outlet in bottom of steel ladle
CN105682826A (en) * 2013-08-26 2016-06-15 日新制钢株式会社 Continuous casting method
CN107974531A (en) * 2016-10-24 2018-05-01 Posco公司 Inclusion content in melting steel reduces device and improves the preparation method of the stainless steel of cleanliness factor
CN108380848A (en) * 2018-06-01 2018-08-10 常州凌风超智科技信息咨询有限公司 A kind of application process of the tundish used for vacuum ingot casting of the double-deck annular slag weir of band
JP2020171955A (en) * 2019-04-12 2020-10-22 日本製鉄株式会社 Continuous casting method for steel

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007044731A (en) * 2005-08-10 2007-02-22 Sumitomo Metal Ind Ltd Pouring tube and pouring method of molten metal
JP4556804B2 (en) * 2005-08-10 2010-10-06 住友金属工業株式会社 Molten metal injection tube and injection method
US8030082B2 (en) 2006-01-13 2011-10-04 Honeywell International Inc. Liquid-particle analysis of metal materials
CN105682826A (en) * 2013-08-26 2016-06-15 日新制钢株式会社 Continuous casting method
CN104525929A (en) * 2014-12-18 2015-04-22 东北大学 Method for controlling steel ladle tapping slag by blowing argon gas to annular steel outlet in bottom of steel ladle
CN107974531A (en) * 2016-10-24 2018-05-01 Posco公司 Inclusion content in melting steel reduces device and improves the preparation method of the stainless steel of cleanliness factor
CN108380848A (en) * 2018-06-01 2018-08-10 常州凌风超智科技信息咨询有限公司 A kind of application process of the tundish used for vacuum ingot casting of the double-deck annular slag weir of band
JP2020171955A (en) * 2019-04-12 2020-10-22 日本製鉄株式会社 Continuous casting method for steel
JP7200811B2 (en) 2019-04-12 2023-01-10 日本製鉄株式会社 Steel continuous casting method

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