JP3926554B2

JP3926554B2 - Electromagnetic stirrer for continuous casting

Info

Publication number: JP3926554B2
Application number: JP2000345679A
Authority: JP
Inventors: 修至脇田
Original assignee: Nippon Steel Corp; Nippon Steel Engineering Co Ltd
Current assignee: Nippon Steel Corp; Nippon Steel Engineering Co Ltd
Priority date: 2000-11-13
Filing date: 2000-11-13
Publication date: 2007-06-06
Anticipated expiration: 2020-11-13
Also published as: JP2002143989A

Description

【０００１】
【発明の属する技術分野】
本発明は、連続鋳造において鋳型内の溶鋼を撹拌するための電磁撹拌装置に関するものである。
【０００２】
【従来の技術】
連続鋳造において、鋳型内に注入された溶鋼に含まれている非金属介在物やガスを積極的に浮上させて除去し、表面品質の優れた鋳片を得るために、鋳型内の溶鋼を電磁撹拌する技術があり、特開昭５４−４２４１号公報などに開示されている。この電磁撹拌装置は、鋳型の長さおよび高さ方向のほぼ全体にわたって設けられており、鋳型冷却水は鋳型の冷却箱の下部より供給され、溶鋼に接する鋳型壁を通って上昇し冷却箱の上部より排出されている。
【０００３】
ところで、表面品質の十分に優れた鋳片を得るためには、電磁撹拌装置のコイルを鋳型内溶鋼の表面にできる限り近付けて、溶鋼表面まで撹拌することが必要である。
そのための技術として実公昭５８−４９１７２号公報には、冷却箱の溶鋼側外面に冷却壁を張設し、冷却壁に設けた冷却溝に冷却水を供給する給水室と、冷却溝からの冷却水を排出する排水室と、電磁撹拌装置を収納する収納室とを設けた装置において、収納室の下に排水室を設け、排水室の下に給水室を設けたものが開示されている。
この技術は、従来、収納室の上にあった排水室を収納室の下に配置することで収納室を溶鋼表面に近付け、溶鋼表面を積極的に撹拌しようとするものである。
【０００４】
また鋳型内の溶鋼表面を積極的に撹拌するものとして、特開平７−３１４１０４号公報が開示されている。この技術は、溶鋼表面の位置が鋳型周辺に設置する電磁撹拌装置のコア中心からコア上端までの範囲にくるように装置を配置して鋳型内溶鋼流を旋回させ、溶鋼の流動を制御する方法である。
また溶鋼の冷却および収納室の保護のため、収納室本体内に冷却水を給水して直接コイルを冷却するとともに溶鋼を冷却することも提案されていた。
【０００５】
【発明が解決しようとする課題】
従来の給水室と排水室を収納室の下側に配置した電磁撹拌装置では、収納室の溶鋼面側に配置した冷却壁に冷却水を通水して、収納室内に収納された電磁撹拌用コイルを溶鋼の熱から保護することのみが考慮されていた。
【０００６】
また、電磁撹拌装置内に収納されるコアの中心からコア上端までの範囲内に溶鋼表面がくるように電磁撹拌用コイルを配置する従来技術では、電磁撹拌装置の保護については開示されていない。この技術では、コア部を溶鋼表面位置に配置すると、電磁撹拌装置の上方に配置されるタンディッシュとの間のスペースに制約があることから、電磁撹拌装置の収納室の天井板は簡単な一枚構造とせざるを得なかった。
【０００７】
この天井板は、コイルを冷却するために収納室内に注入される冷却水で冷却されるが、その構造上収納室上部にエアー溜まりが発生することが多く、天井板がコイルからの誘導電流により異常発熱するという問題があった。
さらに、この状態で鋳型内溶鋼表面が制御異常により上昇して収納室上部に溶鋼がオーバーフローし、天井板が大きく変形して修復不能になるという問題に発展するおそれがあり、従来装置は、電磁撹拌装置の保護という点で十分な冷却構造とはなっていなかった。
また、収納室内に注入される冷却水によりコイル全体の耐水絶縁が時間と共に劣化し、絶縁抵抗が低下してコイルの寿命が低下するという問題もあった。
【０００８】
そこで本発明が解決しようとする課題は、電磁撹拌用コイルを溶鋼表面位置に配置して鋳型内の溶鋼表面を積極的に撹拌するようにした連続鋳造用電磁撹拌装置において、コイル収納室の天井板を効果的に冷却してコイルを保護すると共に、コイルの耐水絶縁劣化による寿命低下、さらには鋳型内溶鋼がオーバーフローした場合でも収納室の変形を回避することである。
【０００９】
【課題を解決するための手段】
上記課題を解決するための本発明は、電磁撹拌用コイルを収納する収納室の溶鋼側外面に冷却壁を張設し、該冷却壁に設けた冷却水路に冷却水を供給する給水室および前記冷却水路からの冷却水を排出する排水室を前記収納室の下側に配設し、前記収納室の天井板を鋳型の天井板とする電磁撹拌装置において、前記電磁撹拌用コイルのコアの上端を溶鋼の表面近傍に設置し、前記収納室の天井板内面に冷却パネルを張設したことを特徴とする連続鋳造用電磁撹拌装置である。
そして、前記冷却パネルに複数の凹部を配列し、該凹部の底に該冷却パネルを天井板に固定するための孔を穿設したものが好ましい。
【００１０】
【発明の実施の形態】
本発明が対象とする連続鋳造設備の例を図５に示す。タンディッシュ１０内の溶鋼はタンディッシュ下部から鋳型４内に注入され、鋳造されて鋳片９となる。溶鋼内の非金属介在物やガスを浮上させ除去して、良好な品質の鋳片９を得るため、鋳型４には電磁撹拌装置１２が設けられている。
【００１１】
本発明の電磁撹拌装置を図に示す例により説明する。図１は電磁撹拌装置の側部断面図、図２は図１のＡ−Ａ矢視平面図である。このように、鋳型４の上部に、電磁撹拌用コイル２を収納する収納室１を設け、収納室１の下側に給水室６と排水室７を配置している。本例は鋳片９の断面が比較的薄い長方形の場合を示し、鋳型４の長辺（冷却壁４−１）に沿って収納室１を設けているが、このほか鋳片９の断面が正方形やそれに近い長方形、あるいは円形等の場合は鋳型４を囲むように収納室１を設ける。
【００１２】
図１のように、給水室６に導入された冷却水は、収納室１の溶鋼側外面に張設されて鋳型４の一部をなす冷却壁４−１に供給され、冷却壁４−１内に形成されている冷却水路を通って、矢印１３のように溶鋼側を上昇しコイル側を下降して排水室７に排水され、鋳型４内に注入された溶鋼を効果的に冷却すると共に、収納室１内に設けられたコイル２の保護も行っている。
本発明装置はこのような電磁撹拌装置において、図１のように収納室１の天井板１１の内面に冷却パネル８を張設している。
【００１３】
本発明装置によれば、冷却壁４−１に冷却水を供給する給水室６と、冷却壁４−１からの冷却水を排出する排水室７とを収納室１の下側に設置したので、収納室１を鋳型４の上部、溶鋼の表面に近づけて設置することができる。このため、鋳型４内の溶鋼表面３まで撹拌が可能となり、鋳片９の品質を一層向上させることができる。
【００１４】
そして、収納室１の天井板１１の内面、すなわちコイル２側に冷却パネル８を張設しているので、冷却パネル８に冷却水を供給して冷却することにより、収納室１内全体に冷却水を注入しなくても、コイル２の発熱による収納室１の温度上昇を防止できる。このためコイルの耐水絶縁劣化による寿命低下といった問題が回避される。
冷却水は、収納室１の外側から図示しない配管等により冷却パネル８に供給し排出することができる。
【００１５】
また、天井板１１の確実な冷却が可能となり、鋳型内溶鋼表面が制御異常により上昇して収納室上部に溶鋼がオーバーフローした場合でも、収納室１は確実に保護される。
電磁撹拌用コイル２のコア５上端を溶鋼の表面３近傍に設置すると、従来技術では収納室１の冷却がスペース的に困難であったが、本発明では天井板１１に冷却パネル８を張設することで、収納室１の冷却が可能となった。
【００１６】
次に、本発明装置における冷却パネル８の詳細について説明する。図３は冷却パネル８の平面図で、図４はその断面拡大図である。冷却パネル８はステンレス製の薄板８−１で形成し、薄板８−１には複数の凹部８−２を配列し、凹部８−２の底に孔８−３を穿設している。
【００１７】
このような冷却パネル８を収納室１の天井板１１の内側に取り付け、凹部８−２の底に設けた孔８−３に溶接材を挿入して天井板１１と溶接する。薄板８−１の端部はスペーサ８−４を介して天井に溶接等により固定する。また薄板８−１の端部あるいはスペーサ８−４に給水口および排水口を設ける。
【００１８】
給水口から冷却水を導入すると、冷却パネル８と天井板１１の間の空間が冷却水で充満され、流動して排水口から排出される。そして配列された凹部８−２によってエアー溜まりの生成が阻止され、効果的な冷却を行うことができる。このため、コイル２の発熱を抑えると共に、鋳型内溶鋼の表面３が上昇して溶鋼のオーバーフロー事故が生じても、収納室１は確実に保護される。
【００１９】
【発明の効果】
以上説明したように、本発明の電磁撹拌装置は鋳型の極力上部に設置できるので、鋳型内溶鋼を表面まで撹拌して良好な品質の鋳片を鋳造することができる。そして電磁撹拌用コイルの収納室の天井板内面に冷却パネルを設けているので、コイル発熱による収納室の温度上昇を抑え、かつコイルの耐水絶縁劣化による寿命低下の問題を解決し、さらには鋳型内溶鋼がオーバーフローした場合でも収納室の変形を回避することができる。
【図面の簡単な説明】
【図１】本発明装置の例を示す側部断面図である。
【図２】本発明装置の例を示し、図１のＡ−Ａ矢視平面図である。
【図３】本発明装置における冷却パネルの例を示す平面図である。
【図４】本発明装置における冷却パネルの例を示す断面図である。
【図５】本発明装置の対象とする連続鋳造設備の例を示す説明図である。
【符号の説明】
１…収納室２…コイル
３…溶鋼表面４…鋳型
４−１…冷却壁
５…コア６…給水室
７…排水室８…冷却パネル
８−１…薄板８−２…凹部
８−３…孔８−４…スペーサ
９…鋳片１０…タンディッシュ
１１…天井板１２…電磁撹拌装置
１３…冷却水流れ方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic stirrer for stirring molten steel in a mold in continuous casting.
[0002]
[Prior art]
In continuous casting, non-metallic inclusions and gases contained in molten steel injected into the mold are actively lifted and removed, and the molten steel in the mold is electromagnetically removed to obtain a slab with excellent surface quality. There is a technique of stirring, which is disclosed in Japanese Patent Laid-Open No. 54-4241. This electromagnetic stirrer is provided over almost the entire length and height of the mold, and the mold cooling water is supplied from the lower part of the mold cooling box, and rises through the mold wall in contact with the molten steel. It is discharged from the top.
[0003]
By the way, in order to obtain a slab of sufficiently excellent surface quality, it is necessary to bring the coil of the electromagnetic stirring device as close as possible to the surface of the molten steel in the mold and stir to the molten steel surface.
As a technology for that purpose, Japanese Utility Model Publication No. 58-49172 discloses a water supply chamber in which a cooling wall is stretched on the outer surface of the molten steel side of the cooling box, cooling water is supplied to the cooling groove provided in the cooling wall, and cooling from the cooling groove. An apparatus provided with a drainage chamber for discharging water and a storage chamber for storing an electromagnetic stirrer is disclosed in which a drainage chamber is provided below the storage chamber and a water supply chamber is provided below the drainage chamber.
In this technique, a drainage chamber that has conventionally been above a storage chamber is disposed below the storage chamber, thereby bringing the storage chamber closer to the surface of the molten steel and actively trying to agitate the molten steel surface.
[0004]
Japanese Patent Laid-Open No. 7-314104 is disclosed as a means for positively stirring the molten steel surface in the mold. This technology is a method of controlling the flow of molten steel by arranging the device so that the position of the molten steel surface is in the range from the core center to the upper end of the core of the electromagnetic stirrer installed around the mold and swirling the molten steel flow in the mold It is.
In addition, in order to cool the molten steel and protect the storage chamber, it has been proposed to supply cooling water into the storage chamber body to directly cool the coil and cool the molten steel.
[0005]
[Problems to be solved by the invention]
In the conventional electromagnetic stirring device in which the water supply chamber and the drainage chamber are arranged on the lower side of the storage chamber, the cooling water is passed through the cooling wall arranged on the molten steel surface side of the storage chamber, and the electromagnetic stirring device is stored in the storage chamber. Only protection of the coil from the heat of the molten steel was considered.
[0006]
Moreover, in the prior art which arrange | positions the coil for electromagnetic stirring so that the molten steel surface may come in the range from the center of the core accommodated in an electromagnetic stirring apparatus to a core upper end, it is not disclosed about protection of an electromagnetic stirring apparatus. In this technique, when the core portion is disposed at the surface of the molten steel, there is a limitation on the space between the core portion and the tundish disposed above the electromagnetic stirrer. It had to be a sheet structure.
[0007]
This ceiling plate is cooled by cooling water injected into the storage chamber in order to cool the coil. However, due to its structure, an air pool often occurs in the upper portion of the storage chamber, and the ceiling plate is caused by an induced current from the coil. There was a problem of abnormal heat generation.
Furthermore, in this state, the molten steel surface in the mold rises due to abnormal control, and the molten steel overflows to the upper part of the storage chamber, and the ceiling plate may be greatly deformed and cannot be repaired. The cooling structure was not sufficient in terms of protecting the stirring device.
In addition, the water-resistant insulation of the entire coil deteriorates with time due to the cooling water injected into the storage chamber, and there is a problem that the insulation resistance is lowered and the life of the coil is reduced.
[0008]
Accordingly, the problem to be solved by the present invention is to provide an electromagnetic stirrer for continuous casting in which a coil for electromagnetic stirring is arranged at a molten steel surface position so as to positively stir the molten steel surface in the mold. In addition to protecting the coil by effectively cooling the plate, the life of the coil is reduced due to deterioration of water-resistant insulation, and further, deformation of the storage chamber is avoided even when the molten steel in the mold overflows.
[0009]
[Means for Solving the Problems]
The present invention for solving the above problems includes a water supply chamber in which a cooling wall is stretched on an outer surface of a molten steel side of a storage chamber for storing an electromagnetic stirring coil, and the cooling water is supplied to a cooling water passage provided in the cooling wall, and In the electromagnetic stirring device in which a drainage chamber for discharging cooling water from the cooling water channel is disposed below the storage chamber, and the ceiling plate of the storage chamber is a ceiling plate of a mold, the upper end of the core of the electromagnetic stirring coil was placed near the surface of the molten steel is an electromagnetic stirrer for continuous casting, characterized in that stretched over the cooling panel to the ceiling panel inner surface of the housing chamber.
It is preferable that a plurality of recesses are arranged in the cooling panel and a hole for fixing the cooling panel to the ceiling plate is formed in the bottom of the recess.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An example of a continuous casting facility targeted by the present invention is shown in FIG. Molten steel in the tundish 10 is poured into the mold 4 from the lower part of the tundish and cast into a slab 9. The mold 4 is provided with an electromagnetic stirrer 12 in order to obtain non-metallic inclusions and gas in the molten steel by floating and removing them to obtain a slab 9 of good quality.
[0011]
The electromagnetic stirrer of the present invention will be described with reference to the example shown in the figure. 1 is a side sectional view of the electromagnetic stirring device, and FIG. 2 is a plan view taken along the line AA of FIG. As described above, the storage chamber 1 for storing the electromagnetic stirring coil 2 is provided in the upper part of the mold 4, and the water supply chamber 6 and the drain chamber 7 are disposed below the storage chamber 1. This example shows a case in which the cross section of the slab 9 is a relatively thin rectangle, and the storage chamber 1 is provided along the long side (cooling wall 4-1) of the mold 4, but in addition, the cross section of the slab 9 is In the case of a square, a rectangle close to it, or a circle, the storage chamber 1 is provided so as to surround the mold 4.
[0012]
As shown in FIG. 1, the cooling water introduced into the water supply chamber 6 is supplied to the cooling wall 4-1 that is stretched on the molten steel side outer surface of the storage chamber 1 and forms a part of the mold 4. Through the cooling water channel formed inside, the molten steel side is raised as shown by the arrow 13 and the coil side is lowered and drained into the drainage chamber 7 to effectively cool the molten steel injected into the mold 4. The coil 2 provided in the storage chamber 1 is also protected.
In the electromagnetic stirring device according to the present invention, a cooling panel 8 is stretched on the inner surface of the ceiling plate 11 of the storage chamber 1 as shown in FIG.
[0013]
According to the apparatus of the present invention, the water supply chamber 6 that supplies the cooling water to the cooling wall 4-1 and the drainage chamber 7 that discharges the cooling water from the cooling wall 4-1 are installed below the storage chamber 1. The storage chamber 1 can be installed close to the upper part of the mold 4 and the surface of the molten steel. For this reason, stirring can be performed up to the molten steel surface 3 in the mold 4, and the quality of the slab 9 can be further improved.
[0014]
And since the cooling panel 8 is extended in the inner surface of the ceiling board 11 of the storage chamber 1, ie, the coil 2, the cooling panel 8 is cooled by supplying cooling water to cool the entire interior of the storage chamber 1. Even if water is not injected, the temperature rise of the storage chamber 1 due to heat generation of the coil 2 can be prevented. For this reason, the problem of the lifetime reduction by deterioration of the water-proof insulation of a coil is avoided.
The cooling water can be supplied to the cooling panel 8 from the outside of the storage chamber 1 through a pipe (not shown) and discharged.
[0015]
Further, the ceiling plate 11 can be reliably cooled, and the storage chamber 1 is reliably protected even when the molten steel surface in the mold rises due to control abnormality and the molten steel overflows to the upper portion of the storage chamber.
When the upper end of the core 5 of the electromagnetic stirring coil 2 is installed in the vicinity of the surface 3 of the molten steel, it is difficult to cool the storage chamber 1 in terms of space in the prior art, but in the present invention, the cooling panel 8 is stretched on the ceiling plate 11. By doing so, the storage chamber 1 can be cooled.
[0016]
Next, the detail of the cooling panel 8 in this invention apparatus is demonstrated. FIG. 3 is a plan view of the cooling panel 8, and FIG. 4 is an enlarged cross-sectional view thereof. The cooling panel 8 is formed of a thin plate 8-1 made of stainless steel. A plurality of recesses 8-2 are arranged in the thin plate 8-1, and a hole 8-3 is formed in the bottom of the recess 8-2.
[0017]
Such a cooling panel 8 is attached to the inside of the ceiling plate 11 of the storage chamber 1, and a welding material is inserted into the hole 8-3 provided at the bottom of the recess 8-2 to be welded to the ceiling plate 11. The end of the thin plate 8-1 is fixed to the ceiling via a spacer 8-4 by welding or the like. Further, a water supply port and a drain port are provided at the end of the thin plate 8-1 or the spacer 8-4.
[0018]
When the cooling water is introduced from the water supply port, the space between the cooling panel 8 and the ceiling plate 11 is filled with the cooling water, flows, and is discharged from the drain port. And the production | generation of an air pool is blocked | prevented by the arranged recessed part 8-2, and effective cooling can be performed. For this reason, while suppressing the heat_generation | fever of the coil 2, even if the surface 3 of the molten steel in a mold raises and the overflow accident of molten steel arises, the storage chamber 1 is reliably protected.
[0019]
【The invention's effect】
As described above, the electromagnetic stirrer according to the present invention can be installed as high as possible in the mold, so that the molten steel in the mold can be stirred to the surface to cast a slab of good quality. And because the cooling panel is provided on the inner surface of the ceiling plate of the storage room of the coil for electromagnetic stirring, the temperature increase of the storage room due to the coil heat generation is suppressed, and the problem of the life reduction due to deterioration of the water-resistant insulation of the coil is solved. Even when the inner molten steel overflows, deformation of the storage chamber can be avoided.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an example of a device of the present invention.
2 shows an example of the device of the present invention, and is a plan view taken along the line AA in FIG.
FIG. 3 is a plan view showing an example of a cooling panel in the apparatus of the present invention.
FIG. 4 is a cross-sectional view showing an example of a cooling panel in the device of the present invention.
FIG. 5 is an explanatory view showing an example of a continuous casting facility which is a target of the apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Storage chamber 2 ... Coil 3 ... Molten steel surface 4 ... Mold 4-1 ... Cooling wall 5 ... Core 6 ... Water supply chamber 7 ... Drainage chamber 8 ... Cooling panel 8-1 ... Thin plate 8-1 ... Concave 8-3 ... Hole 8-4 ... Spacer 9 ... Slab 10 ... Tundish 11 ... Ceiling plate 12 ... Electromagnetic stirrer 13 ... Cooling water flow direction

Claims

A cooling wall is stretched on the molten steel side outer surface of the storage chamber for storing the electromagnetic stirring coil, a water supply chamber for supplying cooling water to the cooling water channel provided in the cooling wall, and a drainage chamber for discharging the cooling water from the cooling water channel In the electromagnetic stirring device using the ceiling plate of the storage chamber as a mold ceiling plate, the upper end of the core of the coil for electromagnetic stirring is installed near the surface of the molten steel, and the storage An electromagnetic stirrer for continuous casting, characterized in that a cooling panel is stretched on the inner surface of the ceiling plate of the chamber.

A cooling wall is stretched on the molten steel side outer surface of the storage chamber for storing the electromagnetic stirring coil, a water supply chamber for supplying cooling water to the cooling water channel provided in the cooling wall, and a drainage chamber for discharging the cooling water from the cooling water channel In the electromagnetic stirrer disposed below the storage chamber, a cooling panel is stretched on the inner surface of the ceiling plate of the storage chamber , a plurality of recesses are arranged in the cooling panel, and the cooling panel is disposed at the bottom of the recess hole electromagnetic stirrer for continuous casting characterized by being bored for fixing a ceiling plate of.