JPH10219340A - Immersion pipe for vacuum degassing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the damage of the outside part of the immersion pipe of a vacuum degassing apparatus for molten metal and to prolong the service life thereof by alternately disposing fixed shape refractory bricks of different lengths by castables in the slag line at the center in the outer peripheral part of the iron core of the immersion pipe described above. SOLUTION: The outer peripheral part of the cylindrical iron core 4 for supporting the lining refractory bricks 1 of the immersion pipe of the vacuum degassing apparatus for subjecting the molten metal, such as molten steel, to degassing and decarburization refining is lined with the MgO-C-based refractory bricks having excellent heat resistance by the high alumina-based castables 2. The MgO-C-based heat resistant fixed shape bricks have the long-sized bricks 6a and short-sized bricks 6b of different lengths, which are aligned with the top ends, and are lined by the castables at the differences in level alternately imparted to the bottom ends. The castable joint is prevented from being damaged by thermal expansion. The dislodgment and damage of the shaped refractory bricks 6a, 6b of the outer peripheral part by the infiltration of the molten metal from the damaged part of the joint is prevented and the service life of the immersion pipe is prolonged.

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】本発明は真空脱ガス装置用浸
漬管の外周部分の損傷を抑制し寿命延長を主目的とした
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly aims at suppressing the damage to the outer peripheral portion of a dip tube for a vacuum degassing apparatus and extending the life.

【０００２】[0002]

【従来の技術】主に溶鋼中の脱ガス、特に脱水素、脱炭
を行なうＲＨ，ＤＨ脱ガス装置の溶鋼浸漬部は浸漬管と
称される。その最も一般的な従来の形状を図１に示す。
詳細はより代表的なＲＨ脱ガス装置の浸漬管で説明す
る。浸漬管の内張りれんがはマグネシア−クロム質れん
が（以後マグクロれんがと称す）、一方外周部はハイア
ルミナ質キャスタブルが配設されている。その損傷要因
は内張りれんが１の溶鋼流による磨耗、熱サイクルによ
るスポーリング、および外周部キャスタブル２のスラグ
ラインの溶損、下段部の脱落等が挙げられる。内張りれ
んが１の損傷についてはマグクロれんがの材質改善によ
って対応されているが、外周および下段部は構造的な問
題もあり満足される状態にない。そんな中で外周部に定
形ＭｇＯ−Ｃれんが６を配する新しいタイプのＲＨ浸漬
管が増加しつつある（特開平７−３４１１９）。これは
スラグラインの溶損という問題を解決し、かつれんがを
支える鉄芯４の変形を抑制することから下部の脱落も抑
制する傾向にあるが、まだその効果は不十分である。そ
の理由はれんが下方のキャスタブルとの境界部の目地溶
損あるいは脱落対策が不十分であることによる。その対
策として浸漬管下段部先端までＭｇＯ−Ｃれんが６の延
長案もいくつか出願されているが実炉においての効果は
全く不十分である。基本的に浸漬管の下段部は鉄芯４が
熱により変形、拡大しキャスタブルが耐え切れずに亀裂
が発生、あるいは熱サイクルによるスポーリングを発生
し最終的には脱落に至るのが最も多い損傷状態である。2. Description of the Related Art A immersion part of a molten steel in a RH or DH degassing apparatus for mainly degassing molten steel, particularly dehydrogenation and decarburization, is called an immersion pipe. The most common conventional shape is shown in FIG.
Details will be described with a more typical immersion pipe of an RH degassing apparatus. The lining brick of the immersion tube has magnesia-chromic brick (hereinafter referred to as magcro brick), while the outer periphery is provided with a high alumina castable. Causes of the damage include abrasion due to the molten steel flow of the lining brick 1, spalling due to a thermal cycle, erosion of the slag line of the outer castable 2, falling off of the lower part, and the like. The damage of the lining brick 1 is dealt with by improving the material of the magcro brick, but the outer periphery and the lower part are not in a satisfactory state due to structural problems. Under such circumstances, a new type of RH immersion tube having a fixed MgO-C brick 6 disposed on the outer periphery thereof is increasing (Japanese Patent Laid-Open No. 7-34119). This solves the problem of erosion of the slag line and suppresses deformation of the iron core 4 supporting the brick, so that the lower portion tends to be prevented from falling off, but the effect is still insufficient. The reason for this is that the joint erosion at the boundary with the castable below the brick or the measures against falling off are insufficient. As a countermeasure, several extensions of the MgO-C brick 6 have been filed to the lower end of the immersion pipe, but the effect in an actual furnace is completely insufficient. Basically, the lower part of the immersion pipe is the damage that the iron core 4 deforms and expands due to heat, and the castable is not able to withstand and cracks occur, or spalling due to thermal cycling ultimately leads to falling off State.

【０００３】[0003]

【発明が解決しようとする課題】真空脱ガス装置浸漬管
外周部の定形ＭｇＯ−Ｃれんがとキャスタブル間の境界
目地損傷とそれに起因する脱落の抑制を課題とした。SUMMARY OF THE INVENTION It is an object of the present invention to suppress joint joint damage between a fixed MgO-C brick and a castable on the outer periphery of a vacuum degassing apparatus immersion pipe and to prevent the joint from falling off.

【０００４】[0004]

【課題を解決するための手段】特開平７−３４１１９で
示される外周定形れんがの抑え方法は上下方向より各々
傾斜状態で支持、固定することが特徴である（図２）。
しかし、特に定形れんが下部の抑え部は溶鋼中に浸漬さ
れるので僅かな隙間にも溶鋼が侵入してしまう。元来Ｍ
ｇＯ−Ｃれんがは表面が滑らかでありキャスタブルとの
密着性は低い。しかも同じ長さの定形ＭｇＯ−Ｃれんが
が配設されると境界目地は一周につながり目地の開き、
地金の侵入に至り易い。目地の開きは基本的に鉄芯４と
外周部耐火物との熱膨脹の差から生れる。鉄芯４の熱膨
脹の方が大きいため耐火物に境界があればそこから開く
ことになる。従って、鉄芯４の膨脹に耐えうる程定形れ
んがとキャスタブルを一体化することが有効である。そ
のため種々の研究の結果、定形れんがの長さ方向、下段
部側に段差を設けキャスタブルを食い込ませ境界目地を
一周化させないことを発明した（図３）。The method for suppressing the outer circumference of the fixed brick shown in Japanese Patent Application Laid-Open No. 7-34119 is characterized in that it is supported and fixed in an inclined state from the vertical direction (FIG. 2).
However, in particular, the holding portion below the shaped brick is immersed in the molten steel, so that the molten steel enters even a small gap. Originally M
The gO-C brick has a smooth surface and low adhesion to castables. Moreover, when a fixed-sized MgO-C brick of the same length is provided, the boundary joint is connected to the circuit and the joint opens.
It is easy to invade bullion. The opening of the joint is basically caused by a difference in thermal expansion between the iron core 4 and the outer peripheral refractory. Since the thermal expansion of the iron core 4 is larger, if there is a boundary in the refractory, it will open from there. Therefore, it is effective to integrate the castable and the fixed brick so as to withstand the expansion of the iron core 4. Therefore, as a result of various studies, we have invented that a step is provided in the lower part of the standard brick in the length direction, so that the castables can be cut in and the boundary joint is not rounded (Fig. 3).

【０００５】[0005]

【実施例】８０ｔ容量のＲＨ脱ガス装置用浸漬管を図４
の如く製造した。内張りれんが１、外周部の定形れんが
ＭｇＯ−Ｃれんが６、キャスタブル２の品質は表１に示
す。外周部の定形れんが６形状は上端部を揃え、長さは
短尺れんが６ｂの３７０ｍｍと長尺れんが６ａの４７０
ｍｍの２種類を交互に配し１００ｍｍの段差を設け、キ
ャスタブル２を食い込ませた。段差は少なくとも３０ｍ
ｍは必要と考えられる。FIG. 4 shows an immersion pipe for an RH degassing apparatus having a capacity of 80 tons.
It was manufactured as follows. Table 1 shows the quality of the lining brick 1, the fixed-form brick MgO-C brick 6 on the outer peripheral portion, and the castable 2. The shape of the fixed brick 6 at the outer periphery is aligned with the upper end, and the length is 370 mm for the short brick 6b and 470 for the long brick 6a.
2 mm were alternately arranged to provide a step of 100 mm, and the castable 2 was bitten. Step is at least 30m
m is considered necessary.

【０００６】[0006]

【表１】[Table 1]

【０００７】[0007]

【発明の効果】実施例でしめされたＲＨ脱ガス用浸漬管
を実炉にて使用した。従来は外周部の定形れんがのＭｇ
Ｏ−Ｃれんがは長さが全て４２０ｍｍであった。この場
合、境界部に目地損傷が発生し下部の脱落に至り１００
ｃｈ程度が平均的な寿命であったが、３７０ｍｍと４７
０ｍｍの段差をつけることにより目地損傷は撲滅され１
４７ｃｈまで寿命は延長することができ大きな効果が認
められた。The immersion pipe for RH degassing described in the examples was used in an actual furnace. Conventionally, the outer periphery of fixed brick Mg
All OC bricks were 420 mm in length. In this case, joint damage occurs at the boundary and the lower part falls off.
The average life was about ch, but 370 mm and 47
Joint damage is eradicated by providing a step of 0 mm, and 1
The life can be extended up to 47 ch, and a great effect has been recognized.

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

【図１】従来のＲＨ脱ガス用浸漬管の断面図である。FIG. 1 is a sectional view of a conventional immersion pipe for degassing RH.

【図２】外周定形れんが型ＲＨ脱ガス用浸漬管の断面図
である。FIG. 2 is a sectional view of an immersion pipe for degassing an outer peripheral fixed brick type RH.

【図３】本発明による段差施工例を示す部分の展開説明
図である。FIG. 3 is a development explanatory view of a portion showing a step construction example according to the present invention.

【図４】本発明の真空脱ガス装置用浸漬管の断面図であ
る。FIG. 4 is a sectional view of a dip tube for a vacuum degassing apparatus according to the present invention.

【符号の説明】[Explanation of symbols]

１ 内張りれんが ２ キャスタブル ３ フランジ ４ 円筒形をなす鉄芯 ５ スタッド ６ 外周部定形れんがＭｇＯ−Ｃ ６ａ 長尺れんが ６ｂ 短尺れんが DESCRIPTION OF SYMBOLS 1 Lined brick 2 Castable 3 Flange 4 Cylindrical iron core 5 Stud 6 Peripheral fixed-shaped brick MgO-C 6a Long brick 6b Short brick

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 真空脱ガス装置用浸漬管において、内張
りれんがを支える鉄芯外周部中央のスラグライン部に定
形れんがを配設し、かつ下側の長さを交互に長短を図り
段差をつけたことを特徴とする真空脱ガス装置用浸漬
管。In an immersion pipe for a vacuum degassing apparatus, a fixed-shaped brick is disposed at a slag line at the center of an outer peripheral portion of an iron core supporting a lining brick, and the lower length is alternately lengthened and shortened to form a step. An immersion tube for a vacuum degassing device, characterized in that: