JPS59159923A - Operating method of rh vacuum degassing device - Google Patents

Abstract

PURPOSE:To permit easy exchanging of an immersion pipe and to extend considerably the life of a lower tank by using more than once the immersion pipe of an RH vacuum degassing device preliminarily to use for rising a molten steel thereby removing the solidified layer in the pipe. CONSTITUTION:The same immersion pipe 14 is first used as a riser up to about half its life and gaseous Ar is blown through a gas blowing pipe 16 to obtain stable reflux of molten steel. Said pipe is used as a downcomer for the remaining half of the life and during this time the gaseous Ar is not blown into the pipe and therefore the molten steel intrudes and solidifies in the pipe 16 thereby cloggint the pipe. The pipe 14 as a downcomer is used temporarily as a riser by blowing the gaseous Ar from an Ar brick 30 in the stage of RH treatment of a non-high grade steel just prior to exchanging of the pipe 14 when the pipe 14 is used to the limit and the other immersion pipe for the riser attains about half of its limit. The base metal slag, etc. sticking the inside surface of a reflux pipe 12 and the pipe 14 are therefore removed, by which the removal of the pipe 14 is made easy and the damage in the brick of the pipe 12 is thoroughly eliminated. The life of a lower tank 6 is thus considerably extended.

Description

【発明の詳細な説明】 本発明はＲＨ真空脱ガス装置の操業方法に係り、特に浸
漬管の取換を容易にし下部槽の寿命を延長できる操業方
法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating an RH vacuum degassing apparatus, and more particularly to a method of operating an RH vacuum degassing apparatus, which facilitates the replacement of the immersion tube and extends the life of the lower tank.

近年、需要者側の鋼使用の技術が進み、鋼中のガス、非
金属介在物などの減少の要求が高ま９、ＲＨ真空脱ガス
法の重要性が増加してきた。In recent years, as steel usage technology on the customer side has progressed, there has been a growing demand for reduction of gases, nonmetallic inclusions, etc. in steel9, and the importance of the RH vacuum degassing method has increased.

ＲＨ脱ガス装置を第１図により説明する。Ｒ，Ｈ脱ガス
槽は上蓋２、中部槽４、下部槽６から構成され上部には
真空用の排気孔８、合金投入口１０が設けられ下部槽６
の底部には環流管１２が設けられ、更にその下部には浸
漬管１４が装着されている。環流管１２と浸漬管１４の
接続部に上昇用ガスとしてＡｒガスを吹き込むポーラス
れんが（以下Ａｒれんがと称する）が従来使用されてい
た。しかしながらＡｒガスの漏洩が生じやすく安定した
溶鋼環流が得難い上に、下部槽６の底部に吹き抜けた場
合は、底部れんがの損耗が著しく、更にＡｒれんが自体
の溶損も太きい等の欠点が多く、これを解決するため浸
漬管１４の内部にパイプを埋め込み、ガス吹込管１６を
設ける方法が考えられ、最近の溶鋼環流量増加の傾向も
あシ、ガス吹込管１６による方法が採用されるようにな
ってきた。The RH degassing device will be explained with reference to FIG. The R and H degassing tank is composed of an upper lid 2, a middle tank 4, and a lower tank 6, and the upper part is provided with a vacuum exhaust hole 8, an alloy inlet 10, and the lower tank 6.
A reflux pipe 12 is provided at the bottom of the reflux pipe 12, and a dipping pipe 14 is further attached to the lower part of the reflux pipe 12. Porous bricks (hereinafter referred to as Ar bricks) have been conventionally used in which Ar gas is blown into the joint between the reflux pipe 12 and the immersion pipe 14 as a rising gas. However, Ar gas tends to leak easily and it is difficult to obtain a stable molten steel circulation, and if it blows through to the bottom of the lower tank 6, there are many disadvantages such as significant wear and tear on the bottom brick and also large melting damage to the Ar brick itself. In order to solve this problem, a method of embedding a pipe inside the immersion pipe 14 and providing a gas blowing pipe 16 has been considered, and considering the recent trend of increasing the flow rate of molten steel, the method using the gas blowing pipe 16 is likely to be adopted. It has become.

ＲＨ真空脱ガス法は上記の装置を使用し、浸漬管１４を
ノードル１８中の溶鋼２０に浸漬し、槽内を０，１〜５
０トールの真空とし大気圧との圧力差によって溶鋼２０
を吸上げ上昇用の浸漬管１４のガス吹込管１６から不活
性ガスを５００〜２０００　ｌ／ｍｉｎ程度吹込み溶鋼
２０を上昇させ他の下降用の浸漬管１４から下降させ、
脱酸、脱水素膜窒素および脱炭を行うのである。なお第
１図においては上昇、下降用にそれぞれ１本づつの浸漬
管１４が示されているが環流量を増加するため、更に浸
漬管１４を増加することもある。The RH vacuum degassing method uses the above-mentioned apparatus, and immerses the immersion tube 14 in the molten steel 20 in the nodule 18, and the inside of the tank is 0.1-5.
A vacuum of 0 torr is applied, and the pressure difference between the atmospheric pressure and the
Inert gas is blown at a rate of about 500 to 2000 l/min from the gas blowing pipe 16 of the immersion pipe 14 for lifting, and the molten steel 20 is raised and lowered from the other immersion pipe 14 for descending.
It performs deoxidation, dehydrogenation membrane nitrogen and decarburization. Although FIG. 1 shows one immersion tube 14 for raising and one for lowering, the number of immersion tubes 14 may be further increased in order to increase the recirculation amount.

このＲＨ真空脱ガス装置において下部槽６、環流管１２
および浸漬管１４の寿命の向上が耐火物原単位管理上き
わめて重要である。一般的に下部槽６の寿命は溶鋼に激
しく洗われ、かつ加熱、冷却の高頻度のサイクルを受け
る環流管１２、浸漬管１４がネックとなっているが、上
昇用と下降用で溶損速度が大きく異なシ、上昇用では、
環流管で０．１〜０．３　ｍｍ　／ヒート、浸漬管で０
．５〜０．８ｒｒｔｍ　／　ヒー）である。一方下降側
については溶損はほとんどない。従って下部槽６と環流
関係の寿命を向上する目的で第２図に示す如く浸漬管は
寿命の前半を上昇用として使用し、後半を下降用として
使用する操業方法が採用されている。第２図において実
線は上昇用、点線は下降用、Ａ印は下部槽の交換、Δ印
は浸漬管の交換を示している。すなわち最初はＡ系列の
環流管、浸漬管を上昇用、Ｂ系列の環流管、浸漬管を下
降用として使用、次にＡ系列の浸漬管の約１／２の寿命
の約６０ヒート後人系列を下降用とし、Ｂ系列の寿命の
きた浸漬管は新しいのと取換えて上昇用として使用する
ものである。以下第２図に示す如く上昇、下降と交互に
繰返すのである。浸漬管を上昇用のみに使用した場合と
上記の如く上昇用から下降用に変更して使用した場合の
浸漬管寿命を比較して第３図に示した。第３図から明ら
かなように浸漬管を上昇用から下降用に変更して使用し
た場合は上昇用にのみ使用した場合より寿命は２倍に向
上する。In this RH vacuum degassing device, a lower tank 6, a reflux pipe 12
In addition, improving the life of the immersion tube 14 is extremely important in terms of unit management of refractories. In general, the life of the lower tank 6 is limited by the reflux pipe 12 and immersion pipe 14, which are washed violently by molten steel and subjected to frequent heating and cooling cycles, but the rate of erosion is high in the ascending and descending pipes. The difference is very different, for rising,
0.1-0.3 mm/heat for reflux tube, 0 for dip tube
．． 5 to 0.8 rrtm/he). On the other hand, there is almost no melting loss on the descending side. Therefore, in order to improve the life of the lower tank 6 and the reflux, an operating method has been adopted in which the immersion pipe is used for the first half of its life for upward movement and for the second half of its life, as shown in FIG. 2. In FIG. 2, the solid line is for ascending, the dotted line is for descending, the mark A indicates replacement of the lower tank, and the mark Δ indicates replacement of the dipping tube. That is, at first, the A series reflux tube and immersion tube were used for ascending, the B series reflux tube and immersion tube were used for descending, and then the human series was used after about 60 heats, which is about 1/2 the life of the A series immersion tube. are used for descending, and the immersion tubes of the B series that have reached the end of their service life are replaced with new ones to be used for ascending. Thereafter, as shown in FIG. 2, rising and falling are repeated alternately. FIG. 3 shows a comparison of the life of the immersion tube when the immersion tube is used only for ascending purposes and when the immersion tube is used for changing from ascending to descending as described above. As is clear from FIG. 3, when the dipping tube is used for changing from ascending to descending, the service life is twice as long as when it is used only for ascending.

しかしながら、上記の如く同一浸漬管を上昇用から下降
用に変更する操業方法をとると、後半を下降用に使用し
た浸漬管を取換える訳であるが、上昇用は環流管、浸漬
管共に内面はれんが目地が露出し付着物がほとんど無い
が、下降用は溶鋼の温度も低くかつ溶鋼に上昇用はど激
しい攪拌がないため、浸漬管れんが内面にスラグと鋼の
混合凝固層が生成している。この層は非常に強固であり
容易に除去できるものではない。従って浸漬管交換時に
は無理に環流管から浸漬管を外させねばならず、その作
業性が悪く、更に環流管れんがを大きく破損させる頻度
が高く、その結果環流管の一部れんが破損のみで、下部
槽全体の取換修理を必要とする事態がしばしば発生し、
従来大きな問題となっていた。However, if we adopt the operation method of changing the same immersion pipe from ascending to descending as described above, the second half of the immersion pipe used for descending will be replaced, but both the reflux pipe and the immersing pipe for ascending will have internal surfaces. The joints of the bricks are exposed and there is almost no deposit, but since the temperature of the molten steel is low in the descending process and there is no vigorous stirring of the molten steel in the ascending process, a mixed solidified layer of slag and steel forms on the inner surface of the immersion pipe brick. There is. This layer is very strong and cannot be easily removed. Therefore, when replacing the immersion tube, the immersion tube must be forcibly removed from the reflux tube, which is not easy to do, and the reflux tube bricks are frequently damaged.As a result, only some bricks of the reflux tube are damaged, and the lower Situations often occur that require the entire tank to be replaced and repaired.
This has traditionally been a big problem.

本発明の目的は上記従来技術の問題点を解決し、浸漬管
の取換えが容易にできるＲＨ真空脱ガス装置の操業方法
を提供するにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above and to provide a method for operating an RH vacuum degassing apparatus in which the immersion tube can be easily replaced.

本発明の要旨とするところは次のとおシである。The gist of the present invention is as follows.

すなわち、浸漬管を環流管に新たに装着後寿命ヒート数
の前半は溶損の多い溶鋼上昇用として使用し後半は溶損
の少ない溶鋼下降用として使用した後肢浸漬管を取換え
るＲＨ真空脱ガス装置の操業方法において、前記浸漬管
の取換えに先立って溶鋼上昇用として１回以上使用し管
内の凝固層を除去することを特徴とする几Ｈ真空脱ガス
装置の操業方法である。In other words, after the immersion tube is newly attached to the reflux tube, the RH vacuum degassing is performed to replace the hind immersion tube, which was used for ascending the molten steel with a lot of melting loss during the first half of its life heat count, and for descending the molten steel with a small amount of melting loss during the second half of its life. A method of operating a vacuum degassing apparatus is characterized in that, prior to replacing the immersion tube, the immersion tube is used one or more times for lifting molten steel to remove a solidified layer inside the tube.

本発明の詳細を実施列とその図面によシ説明する。第４
図は実施例に使用した浸漬管の詳細を示し、浸漬管れん
が２２は鉄板２４とアンカーコイル２６で強化された不
定形耐化物２８でライニングされ、不活性ガス吹込み用
のＡｒれんが（ポーラスれんが）３０とガス吹込管１６
が併設されており、上部には環流管との接続用のフラン
ジ３２が付いている。The details of the present invention will be explained with reference to an embodiment and the drawings. Fourth
The figure shows the details of the immersion tube used in the example.The immersion tube brick 22 is lined with a monolithic reinforced material 28 reinforced with iron plates 24 and anchor coils 26, and is made of Ar bricks (porous bricks) for inert gas injection. ) 30 and gas blowing pipe 16
A flange 32 for connection to the circulation pipe is attached to the upper part.

次に第４図の浸漬管を使用した本発明法を説明する。第
２図に説明した如く同一浸漬管を上昇用と下降用に使用
するのであるが、まず寿命の約半分を上昇用として使用
しこの間はガス吹込管１６を使用してＡｒガスを吹込み
安定した溶鋼環流を得、その後の寿命の半分は下降用と
して使用し、この間はＡｒガスの吹込みをしないためＡ
ｒガズ用のガス吹込管１６には溶鋼が浸入凝固して閉塞
する。次に下降用の浸漬管が寿命に達し、他の上昇用浸
漬管が寿命の約半分に達し下降用浸漬管を取換える直前
に、非高級鋼の几Ｈ処理時にＡｒれんが３０からＡｒガ
スを吹込んで下降用浸漬管を一時的に上昇用に使用する
ことによって環流管、浸漬管の内面に付着している地金
スラグを除去し、その後浸漬管を取換えることによｐ取
外しは極めて容易にな９環流管のれんがの損傷は皆無と
なｐ、下部槽の寿命は大幅に向上した。第５図に本発明
実施列と従来例の下部槽寿命を比較して示した。Next, the method of the present invention using the dip tube shown in FIG. 4 will be explained. As explained in Fig. 2, the same immersion tube is used for ascending and descending, but first, about half of its life is used for ascending, and during this time Ar gas is blown into it using the gas blowing pipe 16 to stabilize it. After that, half of the life is used for descending, and during this period, Ar gas is not injected, so A
Molten steel enters and solidifies into the gas blowing pipe 16 for the r-gaz, causing it to become clogged. Next, when the descending immersion tube reaches the end of its life and the other ascending immersion tube reaches about half its life, and just before replacing the descending immersion tube, Ar gas is applied from Ar brick 30 during the H treatment of non-high grade steel. By blowing in and temporarily using the descending dipping tube for ascending, the base metal slag adhering to the inner surface of the reflux tube and dipping tube can be removed, and then by replacing the dipping tube, p removal is extremely easy. There was no damage to the bricks in the N9 reflux pipe, and the life of the lower tank was greatly improved. FIG. 5 shows a comparison of the lifespan of the lower tank of the present invention example and the conventional example.

ただし第５図の表示は次のとおシである。However, the display in Figure 5 is as follows.

・印二実施例（浸漬管を上昇用と下降用に半々に使用後
一時的に上昇用として使用その後取換え） ○印：従来例（浸漬管を上昇用と下降用に半々に使用後
取換え） 第５図から本発明法においては、下部槽寿命のばらつき
が減少し、寿命が向上しているのがわかる。・Example marked 2 (dipping tube used half for ascending and half for descending, then temporarily used for ascending and then replaced) ○ mark: Conventional example (dipping tube used half for ascending and half descending, then replaced) From FIG. 5, it can be seen that in the method of the present invention, the variation in the life of the lower tank is reduced and the life is improved.

なお、下降用浸漬管を一時的に上昇用として使用するこ
とによって他の上昇用浸漬管は下降用となりガス吹込管
は閉塞するが、そのまま下降用として使用するので問題
はない。Note that by temporarily using the descending dipping tube for ascending, the other ascending dipping tubes are used for descending and the gas blowing tube is blocked, but there is no problem since it is used as is for descending.

また下降用として使用後、一時的に上昇用に切換えた場
合、ＡｒガスをＡｒれんがから凝固層を通して吹込むこ
とは困難であるが、凝固層の微少なき装部や漏洩によシ
少量が出始めれば、溶鋼の上昇流によって凝固層は溶解
され環流は活発となり工程上全く問題は生じていない。Furthermore, when temporarily switching to ascending mode after being used for descending, it is difficult to inject Ar gas from the Ar brick through the coagulated layer, but a small amount of gas may be generated due to small cracks or leakage in the coagulated layer. Once started, the solidified layer is melted by the upward flow of molten steel and the reflux becomes active, causing no problems in the process.

一時的にＡｒれんがからＡｒガスを吹込んで上昇用とし
て使用するヒート回数は通常１〜３ヒートで凝固層をほ
ぼ完全に溶解することができた。The number of heats used for raising the temperature by temporarily blowing Ar gas through the Ar bricks was usually 1 to 3 heats, and the coagulated layer could be almost completely dissolved.

本発明は上記実施例からも明らかな如く、浸漬管を寿命
ヒート数の前半を上昇用として使用し、後半を下降用と
して使用しその取換前に一時的に上昇用として使用する
ことによシ、浸漬管内の凝固層を除去し、取換作業を容
易にし下部槽の寿命を大幅に向上し、耐火物使用原単位
と労務費を減少させる効果をあげることができる。As is clear from the above embodiments, the present invention uses the immersion tube for ascending during the first half of its lifespan, uses it for descending during the latter half, and temporarily uses it for ascending before replacement. B. The coagulated layer inside the immersion pipe is removed, the replacement work is facilitated, the life of the lower tank is greatly extended, and the unit consumption of refractories and labor costs are reduced.

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

第１図はＲＨ真空脱ガス装置を示す断面図、第２図は従
来の環流管および浸漬管の上昇、下降切換使用を示す模
式１程図、第３図は浸漬管の上昇単独使用と第２図に示
した切換使用の場合の浸漬管寿命を示す頻度グラフ、第
４図は本発明実施しｌの浸漬管を示す断面図、第５図は
実施例と従来列の環流管溶損速度と下部槽寿命との関係
を示す図である。 ６・・・下部槽　　　　１２・・・環流管１４・・・浸
漬管　　　　１６・・・ガス吹込管３０・・・ポーラス
れんが（Ａｒれんが）代理人　弁理士　中　路　武　雄 第　１　ロ 第２図 第３図 第４図 第５図Figure 1 is a cross-sectional view of the RH vacuum degassing device, Figure 2 is a schematic diagram showing the use of a conventional reflux tube and immersion tube in ascending and descending directions, and Figure 3 is a diagram showing the use of a conventional reflux tube and immersion tube in ascending and descending directions. Figure 2 is a frequency graph showing the life of the immersion tube in the case of switching use, Figure 4 is a sectional view showing the immersion tube of the present invention, and Figure 5 is the erosion rate of the reflux tube of the embodiment and conventional rows. It is a figure which shows the relationship between and a lower tank lifetime. 6...Lower tank 12...Recirculation pipe 14...Immersion pipe 16...Gas blowing pipe 30...Porous brick (Ar brick) agent Patent attorney Takeo Nakaji 1st b Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

【特許請求の範囲】[Claims] （１）浸漬管を環流管に新たに装着後寿命ヒート数の前
半は溶損の多い溶鋼上昇用として使用し後半は溶損の少
ない溶鋼下降用として使用した後肢浸漬管を取換えるＲ
Ｈ真空脱ガス装置の操業方法において、前記浸漬管の取
換えに先立って溶鋼上昇用として１回以上使用し管内の
凝固層を除去することを特徴とするＲＨ冥空脱ガス装置
の操業方法。(1) After newly attaching the immersion tube to the circulation pipe, replace the hind-limb immersion tube that was used for the first half of the life heat cycle to ascend the molten steel, which has a lot of melting loss, and in the second half, to descend the molten steel, which has a small amount of melting loss.R
A method for operating an RH vacuum degassing device, characterized in that, prior to replacing the immersion tube, the immersion tube is used one or more times for raising molten steel to remove a solidified layer inside the tube.