JP2013245384A - Hot installation method of bottom blowing tuyere in converter - Google Patents

Hot installation method of bottom blowing tuyere in converter Download PDF

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JP2013245384A
JP2013245384A JP2012120890A JP2012120890A JP2013245384A JP 2013245384 A JP2013245384 A JP 2013245384A JP 2012120890 A JP2012120890 A JP 2012120890A JP 2012120890 A JP2012120890 A JP 2012120890A JP 2013245384 A JP2013245384 A JP 2013245384A
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brick
tuyere
drilling
converter
bottom blowing
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JP5920026B2 (en
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Yoshiyuki Nakamura
善幸 中村
Takeshi Matsuzaki
健 松崎
Hisaki Kato
久樹 加藤
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JFE Steel Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a hot installation method for improving a life time of bricks after being drilled in newly installing a new bottom blowing tuyere in a converter bottom.SOLUTION: A magnesia carbon brick is previously arranged, as a brick 6a for drilling, at a part other than an installation part of a bottom blowing tuyere in a converter bottom refractory layer, the magnesia carbon brick containing metallic aluminum of 0.5 to 3 mass%, metallic silicon of 0.1 to 1 mass%, and carbon of 15 to 25 mass%. In installing a new bottom blowing tuyere 1a after an operation period of the converter, a hole 8 is formed in the brick 6a for drilling so as to penetrate the refractory layer, by drilling the brick 6a for drilling from outside of the bottom part with a core bit 15 provided with segments formed by bonding diamond abrasive grains with a binder. Thereafter, a new bottom blowing tuyere 1a in converter is inserted and installed in the through hole 8.

Description

本発明は、転炉底部から鋼浴にガスを吹込んで鋼浴を撹拌して精錬を促進させる、底吹き羽口を新たな底吹き羽口に切り替えるための、転炉底吹き羽口の設置方法に関する。   The present invention is to install a converter bottom blowing tuyere to switch the bottom blowing tuyere to a new bottom blowing tuyere to promote refining by injecting gas into the steel bath from the bottom of the converter and stirring the steel bath. Regarding the method.

上吹きランスからの酸素吹錬によって鋼浴を精錬する転炉においては、転炉内に存在するスラグと鋼浴との反応界面積を増大させること、または鋼浴自体の成分偏析や温度分布などのばらつきを減少させること、によって精錬反応を効率化させるため、転炉底部に設けた底吹き羽口から鋼浴中に攪拌用ガスを吹込み、鋼浴を強攪拌することが広く行われている。また、転炉底部に設けた底吹き羽口から、攪拌用ガスのみならず、精錬用のO2ガスを吹き込むことも行われている。 In a converter that refines a steel bath by oxygen blowing from the top blowing lance, increase the reaction interface area between the slag and the steel bath present in the converter, or segregation of the steel bath itself, temperature distribution, etc. In order to improve the efficiency of the refining reaction by reducing the dispersion of the steel, a stirring gas is blown into the steel bath from the bottom blowing tuyer provided at the bottom of the converter, and the steel bath is strongly stirred. Yes. Further, not only stirring gas but also refining O 2 gas is blown from a bottom blowing tuyer provided at the bottom of the converter.

しかし、底吹き羽口を使用する転炉精錬においては、底吹き羽口周囲の耐火物は他の部位の耐火物に比べて損耗速度が大きいため、底吹き羽口部以外の煉瓦厚みが十分あるにも拘わらず、炉操業を停止せざるを得ない状況となる。そこで、従来、底吹き羽口の寿命を延長するために種々の提案がなされている。   However, in converter refining using bottom-blown tuyere, the refractory around the bottom-blown tuyere has a higher wear rate than refractories in other parts, so the brick thickness other than the bottom-blown tuyere is sufficient. In spite of this, the furnace operation must be stopped. Thus, various proposals have been made in the past to extend the life of the bottom blow tuyere.

例えば、特許文献1には、底吹き羽口以外の場所に、羽口受け煉瓦となる穿孔用煉瓦を予め設置しておき、使用中の羽口の損耗が大きくなって使用に耐えられなくなった時点で、予め設置した前記穿孔用煉瓦に転炉鉄皮外側から穿孔を行って、穿孔が貫通して形成された研削孔に新しい羽口を挿入し、転炉操業を継続する技術が開示されている。この場合、使用に耐えきれなくなった底吹き羽口は、流込み耐火材料、吹付け耐火材料あるいは溶射耐火材料などの適宜の耐火材料によって閉塞される。なお、羽口受け煉瓦とは、羽口の周囲に設置され、羽口を支持し保護する煉瓦である。   For example, in Patent Document 1, a drilling brick that becomes a tuyere receiving brick is installed in a place other than the bottom-blown tuyere in advance, so that the wear of the tuyere in use becomes large and it cannot be used. At that time, a technique is disclosed in which the previously installed drilling brick is drilled from the outside of the converter iron skin, a new tuyere is inserted into the grinding hole formed through the drilling, and the converter operation is continued. ing. In this case, the bottom blowing tuyere that cannot be used is blocked by an appropriate refractory material such as a cast refractory material, a spray refractory material, or a spray refractory material. The tuyere receiving brick is a brick that is installed around the tuyere and supports and protects the tuyere.

また、特許文献2には、損耗した羽口を抜き取り、抜き取った間隙に火炎溶射法によって耐火物を充填し、この充填部に改めて羽口挿入孔を穿孔し、形成した穿孔部に新たな羽口を挿入して羽口を交換する技術が開示されている。
さらに、特許文献3には、熱間にてAOD炉の羽口煉瓦を解体するために、硬質チップと水冷機構を備えたドリルで穿孔する方法が開示されている。
Further, in Patent Document 2, a worn tuyere is extracted, a refractory material is filled in the extracted gap by a flame spraying method, a tuyere insertion hole is drilled in the filling part, and a new tuyere is formed in the formed drilled part. A technique for inserting a mouth and replacing a tuyere is disclosed.
Further, Patent Document 3 discloses a method of drilling with a drill having a hard tip and a water cooling mechanism in order to dismantle the tuyere bricks of the AOD furnace while hot.

特開平9−176720号公報JP-A-9-176720 特開昭59−41414号公報JP 59-41414 A 特開平4−138207号公報JP-A-4-138207

しかしながら、特許文献1および特許文献2に開示のような、予め設置した穿孔用煉瓦や羽口受け煉瓦を転炉の外側から穿孔する場合には、穿孔方法によっては、形成した孔の形状精度が低いために必要以上に挿入する羽口との隙間が大きくなったり、穿孔用煉瓦が穿孔時の衝撃で損傷を受けるなどの不具合が発生する。これらの場合には、交換した羽口の損耗が促進され、底吹き羽口の使用期間は、想定した期間に比べて大幅に短くなってしまう。   However, when drilling a pre-installed drilling brick or tuyere receiving brick from the outside of the converter as disclosed in Patent Document 1 and Patent Document 2, depending on the drilling method, the shape accuracy of the formed hole may be increased. Since it is low, the gap with the tuyere to be inserted more than necessary becomes larger, and problems such as damage to the drilling brick due to impact during drilling occur. In these cases, wear of the replaced tuyere is promoted, and the usage period of the bottom blown tuyere becomes significantly shorter than the assumed period.

特に、穿孔用煉瓦が高温である時に穿孔作業を行うと、穿孔方法によっては穿孔工具の消耗が激しく、施工費用が増大するばかりでなく、作業時間が長くなることによって転炉の不稼動時間が長くなってしまうため問題であった。このために、特許文献3に記載のように、水などの冷媒を用いて穿孔する方法も提案されているが、この方法では耐火物中の物質と水との反応や、冷却による熱衝撃によって耐火物が損傷を受けるため、穿孔した煉瓦を解体除去する場合に限られ、穿孔用煉瓦のように穿孔した後に再度内張り煉瓦として使用されるような場合には適用されていなかった。   In particular, when drilling is performed when the brick for drilling is hot, depending on the drilling method, the consumption of the drilling tool is severe, which not only increases the construction cost, but also increases the work time, resulting in an inoperable time for the converter. It was a problem because it would be long. For this reason, as described in Patent Document 3, a method of perforating using a coolant such as water has also been proposed. However, in this method, a reaction between a substance in a refractory and water or a thermal shock caused by cooling is proposed. Since the refractory is damaged, it is limited to the case where the perforated brick is dismantled and removed, and is not applied to the case where it is used again as a lining brick after perforating like a perforated brick.

本発明は、上記の事情に鑑みてなされたものであり、その目的とするところは、予め転炉底部の底吹き羽口の設置部位以外の部分に配置した穿孔用煉瓦を、転炉の外側から穿孔機により熱間で穿孔して形成された貫通孔に、新たな底吹き羽口を挿入して底吹き羽口を新設するに当たって、前記穿孔用煉瓦の中心部を短時間のうちに精度良く穿孔して貫通孔を形成する際に、穿孔工具の耐久性を確保しつつ、穿孔後の煉瓦の寿命を改善することを可能とする、転炉底吹き羽口の熱間設置方法を提供することにある。   The present invention has been made in view of the above circumstances, and the object of the present invention is to provide a perforated brick previously disposed in a portion other than the installation site of the bottom blowing tuyeres at the bottom of the converter, outside the converter. When a new bottom blowing tuyere is inserted into a through hole formed by hot drilling with a drilling machine, the center of the drilling brick is accurately set in a short time. Providing a hot installation method for converter bottom blowing tuyere that can improve the life of bricks after drilling while ensuring the durability of drilling tools when drilling well to form through holes There is to do.

上記課題を解決するための本発明の要旨は以下のとおりである。
(1)転炉の底部を覆う耐火物層内における、底吹き羽口の設置部位以外の部分に、予め穿孔用煉瓦を配置し、該転炉の使用経過後に前記穿孔用煉瓦に新たな底吹き羽口を設置するに当たり、
前記穿孔用煉瓦として、金属アルミニウム:0.5〜3質量%、金属シリコン:0.1〜1質量%および炭素:15〜25質量%を含有するマグネシアカーボン煉瓦を配置し、前記底部の外側から前記穿孔用煉瓦に対して、硬質セグメントを備えるコアビットにて、該コアビットの先端に給水しつつ穿孔を行って、前記穿孔用煉瓦に前記耐火物層を貫通する孔を形成し、該貫通孔に、新たな転炉底吹き羽口を挿入することを特徴とする転炉底吹き羽口の熱間設置方法。
The gist of the present invention for solving the above problems is as follows.
(1) In the refractory layer covering the bottom portion of the converter, a brick for piercing is disposed in advance in a portion other than the installation site of the bottom blowing tuyere, and a new bottom is added to the piercing brick after the use of the converter. In installing the blowing tuyere,
As the perforating brick, a magnesia carbon brick containing metal aluminum: 0.5-3 mass%, metal silicon: 0.1-1 mass% and carbon: 15-25 mass% is arranged, from the outside of the bottom. With respect to the drilling brick, the core bit having a hard segment is drilled while supplying water to the tip of the core bit to form a hole penetrating the refractory layer in the drilling brick. A method for hot installation of a converter bottom blowing tuyere characterized by inserting a new converter bottom blowing tuyere.

(2)前記穿孔用煉瓦に対する穿孔は、該穿孔前の前記転炉における最後の吹錬終了から20時間以内に行うことを特徴とする前記(1)に記載の転炉底吹き羽口の熱間設置方法。 (2) The heat of the bottom blowing tuyeres according to (1), wherein the perforating brick is perforated within 20 hours from the end of the last blowing in the converter before the perforating. How to install between.

(3)前記穿孔用煉瓦の穿孔開始時の穿孔用ベース煉瓦の温度が500℃以上であることを特徴とする前記(1)または(2)に記載の転炉底吹き羽口の熱間設置方法。 (3) Hot installation of the converter bottom blowing tuyeres according to (1) or (2) above, wherein the temperature of the base brick for drilling at the start of drilling of the brick for drilling is 500 ° C. or more Method.

本発明によれば、転炉の使用を経て該転炉に底吹き羽口を熱間にて新設する際に、羽口受け煉瓦となる一体成形された穿孔用煉瓦を、ダイヤモンド砥粒を結合剤で固結したセグメント等の硬質セグメントを備えたコアビットにて穿孔するため、穿孔の際に周囲の煉瓦を機械的に損傷することなく、穿孔用煉瓦のほぼ中心部に目標とする穿孔方向に沿って精度良く貫通孔を形成することが可能となる。その結果、挿入した羽口の寿命は安定して長くなり、長期間のガス吹込みが実現する。   According to the present invention, when a bottom blowing tuyere is newly installed in the converter through the use of the converter, the integrally formed perforated brick that becomes the tuyere receiving brick is combined with diamond abrasive grains. Drilling with a core bit with a hard segment, such as a segment consolidated with an agent, does not mechanically damage the surrounding bricks when drilling, and in the target drilling direction at the center of the drilling brick. A through-hole can be formed with high accuracy along the line. As a result, the life of the inserted tuyere is stably extended and long-term gas blowing is realized.

また、該コアビットの先端に給水しつつ穿孔するため、高温の煉瓦に対して穿孔を行ってもダイヤモンドセグメントの消耗を最小限に抑制することができ、コアビットに要する費用が削減されると共に、短時間での穿孔作業が可能となる。この際、穿孔用煉瓦として金属アルミニウム0.5〜3質量%、金属シリコン0.1〜1質量%および炭素15〜25質量%を含有するマグネシアカーボンンレンガを用いることから、水と煉瓦の含有物質との反応が抑制されると共に、急冷却の熱衝撃の影響による穿孔用煉瓦の損傷も抑制され、穿孔後に設置する羽口煉瓦および穿孔用煉瓦を穿孔した羽口受け煉瓦の寿命低下を防止することが可能となる。   In addition, since the drilling is performed while supplying water to the tip of the core bit, the wear of the diamond segment can be suppressed to a minimum even if the hot brick is drilled. Drilling work in time is possible. At this time, since a magnesia carbon brick containing 0.5 to 3% by mass of metal aluminum, 0.1 to 1% by mass of metal silicon and 15 to 25% by mass of carbon is used as a perforated brick, the inclusion of water and bricks The reaction with the substance is suppressed, and the damage to the perforated brick due to the effect of thermal shock of rapid cooling is also suppressed, preventing the life of the tuyere brick installed after perforation and the tuyere receiving brick perforated with the perforated brick. It becomes possible to do.

さらに、穿孔用煉瓦の穿孔を、該穿孔前の該転炉の最後の吹錬を終了した後20時間以内に行うこと、そして、穿孔用ベース煉瓦の穿孔開始時の温度を500℃以上にすること、によって、水の影響による穿孔用煉瓦の損傷が広範囲に及んだ結果、穿孔後に設置する羽口煉瓦および穿孔用煉瓦を穿孔した羽口受け煉瓦の寿命が低下する事態を、未然に防ぐことができる。   Further, the perforating brick is perforated within 20 hours after the final blowing of the converter before perforating, and the temperature at the time of perforating start of the perforating base brick is set to 500 ° C. or more. As a result, the damage to the perforated bricks due to the influence of water has been extensively prevented, and the life of the tuyere bricks installed after perforation and the tuyere receiving bricks perforated with the perforated bricks is prevented in advance. be able to.

本発明によれば、穿孔用煉瓦および羽口受け煉瓦の周辺部のワーク煉瓦を傷付けたり、必要以上に研削孔が大きくなるなどの不具合を発生させることなく、かつ穿孔工具の耐久性を確保しつつ、穿孔用煉瓦の中心部を所定の穿孔方向に沿って短時間のうちに精度良く穿孔して貫通孔を形成することが可能になる。従って、穿孔後に設置する羽口煉瓦および穿孔用煉瓦を穿孔した羽口受け煉瓦の寿命低下を確実に防止し得る。   According to the present invention, the durability of the drilling tool is ensured without causing problems such as damaging the work bricks around the perforating bricks and tuyere receiving bricks and unnecessarily large grinding holes. On the other hand, the through hole can be formed by accurately drilling the central portion of the perforating brick along the predetermined perforating direction in a short time. Therefore, it is possible to reliably prevent the life of the tuyere bricks installed after drilling and the tuyere receiving bricks drilled with the drilling bricks.

底吹き羽口を有する転炉の一部を示す断面図である。It is sectional drawing which shows a part of converter which has a bottom blowing tuyere. 本発明の第1の実施形態に係る底吹き羽口の熱間設置方法の工程を説明するための断面図である。It is sectional drawing for demonstrating the process of the hot installation method of the bottom blowing tuyeres concerning the 1st Embodiment of this invention. 本発明の第1の実施形態に係る底吹き羽口の熱間設置方法の穿孔工程を説明するための断面図である。It is sectional drawing for demonstrating the punching process of the hot installation method of the bottom blowing tuyeres which concerns on the 1st Embodiment of this invention.

以下、添付図面を参照して本発明の実施の形態を説明する。
先ず、底吹き羽口を有する転炉の構造について説明する。図1は、底吹き羽口を有する転炉とその羽口部分を拡大した断面図である。
Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the structure of a converter having a bottom blowing tuyere will be described. FIG. 1 is an enlarged cross-sectional view of a converter having a bottom blowing tuyere and its tuyere portion.

図1に示すように、転炉Cは、その外殻をなす鉄皮10と、この鉄皮10の内側の鉄皮10と接触する部分に内張りされた永久煉瓦11と、この永久煉瓦11の内側に張られた消耗部材としてのワーク煉瓦12とを有している。図1ではワーク煉瓦11が1層張りであるが、2層以上の張りとしてもよい。   As shown in FIG. 1, the converter C includes an iron shell 10 that forms an outer shell thereof, a permanent brick 11 that is lined in a portion that contacts the iron shell 10 inside the iron shell 10, and the permanent brick 11. It has a work brick 12 as a consumable member stretched inside. In FIG. 1, the work brick 11 is one-layered, but may be two-layered or more.

転炉Cの底部には、複数の底吹き羽口1が設けられている。これら複数の底吹き羽口1を介して転炉C内の鋼浴にArガス、N2 ガスおよび炭酸ガスなどの攪拌用ガスが、さらには上吹きランスLから精錬用のO2 ガスが、それぞれ吹込まれ、鋼浴を撹拌しつつ精錬が行われる。 At the bottom of the converter C, a plurality of bottom blowing tuyere 1 is provided. Stirring gases such as Ar gas, N 2 gas and carbon dioxide gas are supplied to the steel bath in the converter C through the plurality of bottom blowing tuyere 1, and further O 2 gas for refining from the top blowing lance L, Each is blown and refining is performed while stirring the steel bath.

底吹き羽口1は、転炉Cの底部の鉄皮10内側に設けられる金属製の風箱2と、この風箱2から炉内に向かって上方に延びる、内径が5mm以下の複数のガス吹込用管3と、このガス吹込用管3を覆う羽口煉瓦4と、風箱2の底部に接続され、上述した攪拌用ガスを炉外から風箱2へ供給するためのガス導入管5と、を有している。ガス導入管5を介して風箱2に導入された攪拌用ガスは、風箱2内で均圧化された後に、複数のガス吹込用管3を介して鋼浴中に吹き込まれる。底吹き羽口1は、複数本のガス吹込用管3と羽口煉瓦4とを一体的にプレス成形して構成したものを用いることが好ましい。これにより、非吹錬時のガス消費量を抑制しつつ、羽口の閉塞によるガス流量低下を防止することができる。ただし、底吹き羽口1はこのような構造のものに限るものではなく、例えば1本のガス導入管とそれを覆う被覆耐火物を備えたものであっても良い。   The bottom blowing tuyere 1 includes a metal air box 2 provided inside the iron skin 10 at the bottom of the converter C, and a plurality of gases having an inner diameter of 5 mm or less extending upward from the air box 2 into the furnace. A gas introduction pipe 5 for supplying the above-described stirring gas to the wind box 2 from the outside of the furnace, connected to the bottom of the wind box 2 and the tuyere brick 4 covering the gas blow pipe 3. And have. The stirring gas introduced into the wind box 2 through the gas introduction pipe 5 is equalized in the wind box 2 and then blown into the steel bath through the plurality of gas blowing pipes 3. As the bottom blow tuyere, it is preferable to use a structure in which a plurality of gas blowing pipes 3 and tuyere bricks 4 are integrally formed by press molding. Thereby, the gas flow rate fall by the closing of a tuyere can be prevented, suppressing the gas consumption at the time of non-blowing. However, the bottom blowing tuyere 1 is not limited to the one having such a structure, and may be provided with, for example, one gas introduction pipe and a covered refractory covering the gas introduction pipe.

この底吹き羽口1は、さらにワーク煉瓦の一部を形成する羽口ブロック煉瓦6と一体化するようにプレス成形を施され、羽口ブロック煉瓦6と一体にベース煉瓦7の上に設置される。あるいは、底吹き羽口1を、ベース煉瓦7を貫通させて、別途成形した羽口ブロック煉瓦6に嵌め込んで設置しても良く、この場合羽口ブロック煉瓦6は羽口受け煉瓦として機能する。   The bottom-blown tuyere 1 is press-molded so as to be integrated with the tuyere block brick 6 that forms a part of the work brick, and is installed on the base brick 7 integrally with the tuyere block brick 6. The Alternatively, the bottom-blown tuyere 1 may be installed by being inserted into a separately formed tuyere block brick 6 through the base brick 7. In this case, the tuyere block brick 6 functions as a tuyere receiving brick. .

ここで、底吹き羽口1が存在しているベース煉瓦7の外側には、鉄皮10に連続するフランジ100が設けられている。このフランジ100は、鉄皮10の適宜位置に複数配置されるのが通例である。このフランジ100には、羽口押えフランジ蓋13がボルト締めされる。ベース煉瓦7及び風箱2と羽口押えフランジ蓋13との間には、羽口押え煉瓦14を介在させる。   Here, a flange 100 continuous with the iron skin 10 is provided outside the base brick 7 where the bottom blow tuyere 1 is present. In general, a plurality of the flanges 100 are arranged at appropriate positions on the iron skin 10. A tuyere presser flange cover 13 is bolted to the flange 100. A tuyere presser brick 14 is interposed between the base brick 7 and the wind box 2 and the tuyere presser flange lid 13.

ところで、底吹き羽口1の周囲に設けられた羽口ブロック煉瓦6は、吹き込みガスによって強撹拌される鋼浴から激しい侵蝕を受け、他の部位よりも溶損速度が速く、残存厚さが急速に減少する。これに伴い底吹き羽口1の鋼浴側先端部も溶損され、底吹き羽口1の残存厚みが所定値に達すると、当該羽口からのガス吹込みを停止して、羽口を耐火物で閉塞する必要が生じる。また、これにより羽口数が減少するため、この段階で底吹き羽口を新たに熱間で設置する必要が生じる。
ここで、羽口を新設するための孔をコアビットにて穿つ際に、該コアビットの温度上昇を抑制し、かつ穿孔時の潤滑性を確保するために該コアビットを冷却するが、その際に冷間で作業を行うと、耐火煉瓦に冷却水が供給されたときに該耐火煉瓦の周囲にも冷却水が供給され、この水との反応により耐火物が損傷されるため、底吹き羽口の新設は熱間で行う必要がある。すなわち、底吹き羽口の新設を冷間で行うと、熱間の場合のように冷却水の蒸発がないことから、煉瓦相互間の目地から冷却水が浸入する結果、耐火物の損傷をまねくことになる。また、冷却に伴う炉停止時間の延長を回避し、転炉の生産性を阻害しないためにも、熱間で行う必要がある。
By the way, the tuyere block brick 6 provided around the bottom-blown tuyere 1 is violently eroded from the steel bath strongly stirred by the blowing gas, has a higher erosion rate than other parts, and has a remaining thickness. Decreases rapidly. As a result, the steel bath side tip of the bottom blowing tuyere 1 is also melted, and when the remaining thickness of the bottom blowing tuyere 1 reaches a predetermined value, the gas blowing from the tuyere is stopped and the tuyere is turned off. It becomes necessary to close with refractories. Moreover, since this reduces the number of tuyere, it is necessary to newly install a bottom blowing tuyere at this stage.
Here, when a hole for newly installing a tuyere is drilled with a core bit, the core bit is cooled in order to suppress temperature rise of the core bit and to ensure lubricity during drilling. When the work is carried out between the two, when cooling water is supplied to the refractory brick, the cooling water is also supplied around the refractory brick, and the reaction with the water damages the refractory. The new construction must be done hot. In other words, if the bottom blowing tuyere is installed cold, there is no evaporation of the cooling water as in the case of hot, so that cooling water enters from the joints between the bricks, resulting in damage to the refractory. It will be. Moreover, it is necessary to carry out in order to avoid extending the furnace stop time accompanying cooling and not hindering the productivity of the converter.

以上の技術的背景の下、羽口を新設することになり、その場合の、底吹き羽口の熱間設置方法について、以下に具体的に説明する。
すなわち、転炉操業開始時に設けた底吹き羽口とは異なる部位に、予め穿孔用煉瓦を配置し、この穿孔用煉瓦に穿孔し、この穿孔用煉瓦の貫通孔に新たな底吹き羽口を設置する、本発明の実施形態について、図2を参照して説明する。図2は、本発明の実施形態に係る底吹き羽口の熱間設置方法の工程を説明するための、羽口新設部分の断面図である。
Under the above technical background, a tuyere will be newly installed, and the method for hot installation of the bottom blowing tuyere in that case will be specifically described below.
In other words, drilling bricks are arranged in advance in a part different from the bottom blowing tuyer provided at the start of the converter operation, drilled into the drilling brick, and a new bottom blowing tuyere is inserted into the through hole of the drilling brick. An embodiment of the present invention to be installed will be described with reference to FIG. FIG. 2 is a cross-sectional view of a new tuyere part for explaining the steps of the hot-blowing tuyere installation method according to the embodiment of the present invention.

新たな羽口形成部分には、ワーク煉瓦12および永久煉瓦11の転炉内への施工時に、予め一体成形耐火物からなる穿孔用煉瓦6aを配置しておく。この場合に、穿孔用煉瓦6aは、転炉外側からの穿孔作業及び羽口の取り付け作業を容易にするために、上述のフランジ100が鉄皮10に取り付けられた箇所に配置される。   In the new tuyere formation part, when the work brick 12 and the permanent brick 11 are installed in the converter, a brick 6a for drilling made of an integrally molded refractory is arranged in advance. In this case, the piercing brick 6a is disposed at a position where the above-described flange 100 is attached to the iron skin 10 in order to facilitate the piercing work and the tuyere attaching work from the outside of the converter.

本実施形態では、まず、図2(a)に示すように、フランジ100のフランジ面を基準面としておき、長手方向を穿孔方向とする穿孔用煉瓦6aを、予め、その長手方向すなわち穿孔方向が基準面に対して垂直となる配置とする。本実施形態では、フランジ100はフランジ面が鉄皮10に対して平行となるように配置されているから、穿孔用煉瓦6aの長手方向を鉄皮10に対して垂直となる配置としても同じことである。   In this embodiment, first, as shown in FIG. 2 (a), a drilling brick 6a having the flange surface of the flange 100 as a reference plane and having the longitudinal direction as the drilling direction is previously set in the longitudinal direction, that is, the drilling direction. The arrangement is perpendicular to the reference plane. In the present embodiment, since the flange 100 is arranged so that the flange surface is parallel to the iron skin 10, the same thing can be said even if the longitudinal direction of the drilling brick 6a is perpendicular to the iron skin 10. It is.

通常、転炉のワーク煉瓦12は、図2に示すように、その長手方向が鉄皮10に対して垂直となる方向に配置されており、また、ワーク煉瓦12に挟まれて設置される穿孔用煉瓦6aもその長手方向が鉄皮10に対して垂直となる方向に設置されているが、ワーク煉瓦および穿孔用煉瓦が鉄皮10に対して垂直に設置されていない場合には、フランジ100を、フランジ面がワーク煉瓦および穿孔用煉瓦と垂直となる方向に、予め設置しておく必要がある。この場合には、当然ではあるがフランジ面と鉄皮面とは平行にはならない。   Usually, the work brick 12 of the converter is arranged in a direction in which the longitudinal direction is perpendicular to the iron skin 10 as shown in FIG. The brick 6a is also installed in a direction in which the longitudinal direction is perpendicular to the iron skin 10. However, when the work brick and the perforating brick are not installed perpendicular to the iron skin 10, the flange 100a. Must be installed in advance in a direction in which the flange surface is perpendicular to the work brick and the drilling brick. In this case, as a matter of course, the flange surface and the iron skin surface are not parallel to each other.

次に、穿孔用煉瓦6aの具体的な施工方法について詳述する。
まず、ボルト(図示せず)によってフランジ100とフランジ蓋13aとを固着しておき、押え煉瓦14aを、その上面が鉄皮10の内面と略一致するようにフランジ蓋13aの上に設置する。次いで、穿孔用ベース煉瓦7aを、穿孔用煉瓦6aを設置する面がフランジ100のフランジ面と平行になるように、鉄皮10及び押え煉瓦14aの上に設置する。その後、穿孔用ベース煉瓦7aの周辺に永久煉瓦11を配置して転炉の永久張りを構成する。
なお、永久張りから施工する場合の施工方法であるが、永久張りが施工済みであってワーク煉瓦のみ施工し直す場合は、使用済みの底吹き羽口およびワーク煉瓦を除去して、設置済みのベース煉瓦7aを再使用することができる。この際、穿孔されたベース煉瓦7aの穿孔された部分には、適当に成形した煉瓦を挿入してモルタル等で固定するようにすれば良い。
Next, a specific construction method of the perforating brick 6a will be described in detail.
First, the flange 100 and the flange lid 13a are fixed with bolts (not shown), and the presser brick 14a is placed on the flange lid 13a so that the upper surface thereof substantially coincides with the inner surface of the iron skin 10. Next, the perforating base brick 7a is installed on the iron shell 10 and the holding brick 14a so that the surface on which the perforating brick 6a is installed is parallel to the flange surface of the flange 100. Thereafter, permanent bricks 11 are arranged around the perforating base brick 7a to constitute permanent tension of the converter.
In addition, it is a construction method in the case of construction from permanent tension, but when permanent tension has been constructed and only work bricks are re-installed, the used bottom blowing tuyeres and work bricks are removed and installed. The base brick 7a can be reused. At this time, a suitably shaped brick may be inserted into the perforated portion of the perforated base brick 7a and fixed with mortar or the like.

次いで、穿孔用ベース煉瓦7aの上に、フランジ100のフランジ面に対してその長手方向軸心が垂直となるように穿孔用煉瓦6aを設置する。その後、穿孔用煉瓦6aの周辺にワーク煉瓦12を配置して転炉の内張りを構成する。この際、穿孔用煉瓦6aは、羽口ブロック煉瓦6、羽口煉瓦4及び風箱2を組み合わせたものと同一形状に、成形したものを用いることが望ましい。これにより、羽口およびその周囲と穿孔用煉瓦およびその周囲との、煉瓦形状を共通化できるため、煉瓦の製造コストが低減されるだけでなく、羽口および穿孔用煉瓦の配置の自由度を増大して、配置の変更を容易にすることができる。また穿孔用煉瓦6aには、均一な材質で一体にプレス成形されたものを用いることが望ましい。これにより、穿孔後にも内部に欠陥が生じ難い、強固な構造とすることができる。   Next, the perforating brick 6a is installed on the perforating base brick 7a so that its longitudinal axis is perpendicular to the flange surface of the flange 100. Thereafter, the work brick 12 is arranged around the perforating brick 6a to constitute the lining of the converter. At this time, the perforated brick 6a is preferably formed into the same shape as the combination of the tuyere block brick 6, the tuyere brick 4 and the wind box 2. This allows the brick shape to be shared between the tuyere and its surroundings and the perforated brick and its perimeter, which not only reduces the manufacturing cost of bricks, but also increases the freedom of placement of the tuyere and perforating bricks. It can be increased to facilitate changing the arrangement. The perforated brick 6a is preferably one that is integrally press-formed with a uniform material. As a result, it is possible to obtain a strong structure in which defects are not easily generated even after drilling.

上記に従って予め穿孔用煉瓦6aの穿孔方向が基準面に垂直になる配置としたならば、次に、図2(b)に示すように、鉄皮10の外側から穿孔用煉瓦6aに、コアビット15によって前記基準面に垂直な方向に穿孔を行う。この工程は、使用中の底吹き羽口が損耗するなどして使用を停止した場合に、新たに底吹き羽口を熱間にて設置する必要が生じた際に行われる。   If the perforation brick 6a is arranged in advance so that the perforation direction of the perforation brick 6a is perpendicular to the reference plane, then as shown in FIG. 2 (b), the core bit 15 is placed on the perforation brick 6a from the outside of the iron skin 10. To drill in a direction perpendicular to the reference plane. This step is performed when it is necessary to newly install the bottom blowing tuyere when the use is stopped because the used bottom blowing tuyere is worn out.

この工程においては、まず、転炉内の溶鋼およびスラグを排出し、適宜の角度で転炉を傾動させた状態(通常は穿孔方向が水平となるように傾動させる)で維持し、フランジ蓋13a及び押え煉瓦14aを取り外す。その後、フランジ100と、コアビット15が取り付けられた回転動力を有する、図示しないコアドリルの取付用フランジとを連結する。これによりコアビット15はフランジ100の中心部と自動的に芯合わせされる。なお、フランジ100にコアドリルを連結することによって穿孔位置及び方向の精度が向上するが、穿孔機を連結できない場合には、別の方法で転炉炉体とコアドリルとを相対的に位置決めして固定出来れば、コアドリルを転炉作業床に配置しても構わない。   In this process, first, the molten steel and slag in the converter are discharged, and the converter is tilted at an appropriate angle (usually tilted so that the drilling direction is horizontal), and the flange lid 13a. And the presser brick 14a is removed. Thereafter, the flange 100 and a mounting flange of a core drill (not shown) having rotational power to which the core bit 15 is mounted are connected. As a result, the core bit 15 is automatically aligned with the center of the flange 100. Although the accuracy of drilling position and direction is improved by connecting the core drill to the flange 100, if the drilling machine cannot be connected, the converter furnace body and the core drill are positioned and fixed by another method. If possible, the core drill may be arranged on the converter work floor.

そして、フランジ100のフランジ面に垂直な方向かつフランジ100の中心に向けて、コアドリルにて回転が与えられたコアビット15を押し進めて、穿孔用ベース煉瓦7a及び穿孔用煉瓦6aに穿孔を施して貫通孔8を形成する。穿孔用ベース煉瓦7aの代わりに、所定の大きさの孔が予め設置されたベース煉瓦7を使用し、孔に挿入された耐火物を除去して貫通孔8を形成してもよい。   Then, the core bit 15 rotated by the core drill is pushed in a direction perpendicular to the flange surface of the flange 100 and toward the center of the flange 100 to perforate the perforating base brick 7a and the perforating brick 6a. Hole 8 is formed. Instead of the perforating base brick 7a, a base brick 7 in which a hole of a predetermined size is previously installed may be used, and the refractory inserted into the hole may be removed to form the through hole 8.

ここで、穿孔用のコアビット15は、先端にダイヤモンド砥粒を例えばメタルボンドの結合剤で固結したダイヤモンドセグメントや、タングステン鋼、モリブデン鋼およびバナジウム鋼の超硬合金製のセグメント等の硬質セグメント16を備えていることが肝要であり、このコアビット15を用いて穿孔を行うことによって、貫通孔8の周囲に機械的な衝撃力を与えることなく高速での研削を実現することができる。
すなわち、ダイヤモンドセグメントを備えるコアビットは、超硬質のダイヤモンド砥粒ビットがセグメントの円周上に存在するため、通常のドリル穿孔に比べて穿孔時に周囲の耐火煉瓦との間に隙間を生じることがなく、精度の良い穿孔が実現する。同様に、超硬合金製のセグメント、例えばタングステンカーバイド(WC)粉末をコバルトやニッケルで固結したタングステン鋼セグメントを備えるコアビットは、セグメント自体が超硬質であるため、やはり精度の良い穿孔が実現する。
Here, the core bit 15 for drilling includes a hard segment 16 such as a diamond segment obtained by solidifying diamond abrasive grains at the tip with, for example, a metal bond binder, or a segment made of cemented carbide of tungsten steel, molybdenum steel, or vanadium steel. It is essential that the core bit 15 is provided, and by drilling using the core bit 15, high-speed grinding can be realized without applying mechanical impact force around the through-hole 8.
That is, the core bit with diamond segments has a super hard diamond abrasive bit on the circumference of the segment, so there is no gap between the surrounding refractory bricks when drilling compared to ordinary drilling. Highly accurate drilling is realized. Similarly, a core bit including a cemented carbide segment, for example, a tungsten steel segment obtained by consolidating tungsten carbide (WC) powder with cobalt or nickel, can be drilled with high accuracy because the segment itself is superhard. .

また、コアビット15は、一体に形成されたものでも、複数の金属管をネジで接続する方式のものでも良いが、その全長と外径の比(全長/外径)を20以下とすることにより、コアビット15の剛性を十分に高くすることができ、方向精度の高い穿孔が可能となる。   The core bit 15 may be formed integrally or may be a system in which a plurality of metal tubes are connected with screws, but the ratio of the total length to the outer diameter (total length / outer diameter) is set to 20 or less. The rigidity of the core bit 15 can be sufficiently increased, and drilling with high directional accuracy is possible.

さらに、コアビット15の先端には、図3に示すように、コアドリルの回転軸17を介して、冷却水18を供給するようにする。これにより高温の煉瓦に穿孔する場合でも、ダイヤモンドセグメント16の消耗を抑制してコアビットの費用を抑制しつつ、高速で穿孔することが可能となる。また、冷却水18は、煉瓦の研削屑を円筒状の研削溝から排出してコアビットの潤滑を確保する役割も果たす。従って、冷却水量は、研削溝の手前側のコアビットの入り口から、液状で排出される程度に状況に応じて調節するようにする。研削溝が貫通すると、冷却水は手前側ではなく炉内側に流入するようになるので、貫通を検知することもできる。
ここで、冷却水は、穿孔中に研削溝の手前側のコアビットの入り口から液状で排出されることが重要であり、液状で排出されない場合、コアビットの潤滑が不充分となり、コアビットの振動が大きくなることにより、施工精度が悪化する、おそれがある。従って、冷却水が、穿孔中に研削溝の手前側のコアビットの入口から液状で排出される程度の、供給量を確保することが好ましい。
Further, as shown in FIG. 3, cooling water 18 is supplied to the tip of the core bit 15 via the rotating shaft 17 of the core drill. As a result, even when drilling in a high-temperature brick, drilling can be performed at high speed while suppressing the consumption of the diamond segment 16 and the cost of the core bit. The cooling water 18 also serves to ensure lubrication of the core bit by discharging brick grinding waste from the cylindrical grinding groove. Therefore, the amount of cooling water is adjusted according to the situation to the extent that it is discharged in liquid form from the entrance of the core bit on the front side of the grinding groove. When the grinding groove penetrates, the cooling water flows into the inside of the furnace instead of the front side, so that the penetration can be detected.
Here, it is important that the cooling water is discharged in liquid form from the entrance of the core bit on the near side of the grinding groove during drilling. If it is not discharged in the liquid state, the lubrication of the core bit becomes insufficient and the vibration of the core bit is large. As a result, the construction accuracy may deteriorate. Therefore, it is preferable to secure a supply amount such that the cooling water is discharged in liquid form from the inlet of the core bit on the near side of the grinding groove during drilling.

所定の穿孔処理が終了した時点で、穿孔孔の状態を確認し、コアドリルをフランジ100から取り外し、図2(c)に示すように、貫通孔8にガス吹込用管3aとこの管の外周を覆う羽口煉瓦4aとを円柱状に一体成形した新たな底吹き羽口1aを挿入する。新たな底吹き羽口1aは、複数本のガス吹込用管3aと羽口煉瓦4aとを一体的にプレス成形して構成したものを用いることが好ましい。これにより、非吹錬時のガス消費量を抑制しつつ、羽口の閉塞によるガス流量低下を防止することができる。ただし、底吹き羽口はこのような構造のものに限るものではなく、例えば1本のガス導入管とそれを覆う被覆耐火物を備えたものであっても良い。   When the predetermined drilling process is completed, the state of the drill hole is confirmed, the core drill is removed from the flange 100, and the gas blowing pipe 3a and the outer periphery of this pipe are placed in the through hole 8 as shown in FIG. A new bottom-blown tuyere 1a formed by integrally molding the covering tuyere brick 4a into a cylindrical shape is inserted. As the new bottom blown tuyere 1a, it is preferable to use one formed by integrally pressing a plurality of gas blowing pipes 3a and tuyere bricks 4a. Thereby, the gas flow rate fall by the closing of a tuyere can be prevented, suppressing the gas consumption at the time of non-blowing. However, the bottom blowing tuyere is not limited to the one having such a structure, and may be provided with, for example, one gas introduction pipe and a covered refractory covering the gas introduction pipe.

ここで、貫通孔8の内側面と新たな底吹き羽口1aの外側面の隙間は2mm以下、より望ましくは1mm以下とする。すなわち、この隙間が2mmより大きくなると、新たな底吹き羽口の損耗速度が増大する問題がある。前記のような穿孔方法を採用することにより、高い穿孔精度が確保され、隙間を1mm程度以下に制御することが可能である。新たな底吹き羽口1aを貫通孔8に挿入する際には、外側面に耐火モルタルを塗るようにする。これにより、前記隙間に耐火モルタルがある程度充填され、隙間に起因する新たな底吹き羽口の耐用性の劣化は見られない。作業時間等の条件が許容できれば、新たな底吹き羽口1aを挿入した後に隙間にモルタルを圧入するようにしても良い。   Here, the gap between the inner surface of the through hole 8 and the outer surface of the new bottom blowing tuyere 1a is 2 mm or less, more preferably 1 mm or less. That is, when this gap becomes larger than 2 mm, there is a problem that the wear rate of a new bottom blowing tuyere increases. By adopting the drilling method as described above, high drilling accuracy is ensured, and the gap can be controlled to about 1 mm or less. When a new bottom blowing tuyere 1a is inserted into the through-hole 8, refractory mortar is applied to the outer surface. As a result, the gap is filled with refractory mortar to some extent, and there is no deterioration in the durability of the new bottom blowing tuyere due to the gap. If conditions such as work time are acceptable, mortar may be pressed into the gap after inserting a new bottom blowing tuyere 1a.

新たな底吹き羽口1aの挿入後、図2(d)に示すように、ガス導入管5を通して、羽口押え煉瓦14を挿入した後、羽口押えフランジ蓋13と炉底フランジ100を図示しないボルトで固着する。なお、コアドリルを連結するためのネジ孔等の部材が何らかの損傷を受けた場合に交換を容易にするため、さらに中間フランジを介して、コアドリルあるいはフランジ蓋13aをフランジ100に連結するようにしても良い。
その後、ガス導入管5を、図示しないガス供給設備からの配管に接続して、新たな底吹き羽口1aからのガス吹込みを可能とする。さらに、新たな底吹き羽口1aも含めて炉全体のワークレンガを、炉内にコークスを投入すると共に上吹き酸素を供給するなどして、数時間かけて予熱した後、転炉としての溶鋼の精錬処理に供する。
After inserting the new bottom blown tuyere 1a, as shown in FIG. 2 (d), the tuyere presser brick 14 is inserted through the gas introduction pipe 5, and then the tuyere presser flange lid 13 and the furnace bottom flange 100 are shown. Do not fasten with bolts. In order to facilitate replacement when a member such as a screw hole for connecting the core drill is damaged, the core drill or the flange lid 13a may be connected to the flange 100 via an intermediate flange. good.
Thereafter, the gas introduction pipe 5 is connected to a pipe from a gas supply facility (not shown) so that gas can be blown from a new bottom blowing tuyere 1a. Furthermore, the work bricks of the entire furnace including the new bottom blowing tuyere 1a are preheated over several hours by supplying coke into the furnace and supplying top blowing oxygen, and then molten steel as a converter. Used for refining process.

また、穿孔用煉瓦6aは、炭素15〜25質量%を含有するマグネシアカーボンレンガであって、さらに金属アルミニウム0.5〜3質量%および金属シリコン0.1〜1質量%を含有するものを用いる必要がある。すなわち、炭素含有量が15質量%未満では、耐熱衝撃性が低下して、穿孔時の冷却水18により急冷される部分が損傷を受けるため、新たな底吹き羽口1aの損耗速度が増大する。一方、炭素含有量が25質量%を超えると、耐酸化性が低下するとともに、溶鉄による侵食速度も増大する。炭素源としては、各種黒鉛の他、カーボンブラック、ピッチなどが使用できる。   Further, the perforating brick 6a is a magnesia carbon brick containing 15 to 25% by mass of carbon and further containing 0.5 to 3% by mass of metallic aluminum and 0.1 to 1% by mass of metallic silicon. There is a need. That is, if the carbon content is less than 15% by mass, the thermal shock resistance is lowered, and the portion rapidly cooled by the cooling water 18 at the time of drilling is damaged, so that the wear rate of the new bottom blowing tuyere 1a increases. . On the other hand, when the carbon content exceeds 25% by mass, the oxidation resistance decreases and the erosion rate by the molten iron also increases. As the carbon source, carbon black, pitch and the like can be used in addition to various graphites.

また、金属アルミニウム含有量が0.5質量%未満では、高温強度が低下するため、穿孔用煉瓦6aおよび新たな底吹き羽口1aの損耗速度が増大する。一方、金属アルミニウム量が3質量%を超えると、損耗速度の低減に効果的でなく、また炭化アルミニウム生成量が過大になることから穿孔時の冷却水18との反応による損傷を受け易くなり、新たな底吹き羽口1aの損耗速度が増大する。従って、金属アルミニウム含有量は0.5〜3質量%とする。金属アルミニウム源としては、金属アルミニウム粉末の他、後述するAl−Si合金粉末も使用できる。   Further, when the metal aluminum content is less than 0.5% by mass, the high-temperature strength is lowered, so that the wear rate of the perforating brick 6a and the new bottom blowing tuyere 1a is increased. On the other hand, if the amount of metallic aluminum exceeds 3% by mass, it is not effective in reducing the wear rate, and the amount of aluminum carbide produced becomes excessive, so that it is easily damaged by reaction with the cooling water 18 during drilling, The wear rate of the new bottom blowing tuyere 1a increases. Therefore, the metal aluminum content is set to 0.5 to 3% by mass. As a metal aluminum source, Al-Si alloy powder described later can be used in addition to metal aluminum powder.

金属シリコンを金属アルミニウムと共に添加すると、生成する炭化物(AlSiC)の水との反応性が、炭化アルミニウム(Al)に比べて低下するため、穿孔時の冷却水18との反応による穿孔用煉瓦6aの損傷を抑制することができる。この金属シリコン含有量が0.1質量%未満では、炭化アルミニウム生成の抑制効果が十分でないため、穿孔時の冷却水18との反応の影響による新たな底吹き羽口1aの損耗速度増大を十分に抑制できない。一方、金属シリコン含有量を1質量%より増やしてもさらに損耗抑制効果が向上する訳ではなく、むしろ耐食性が低下する傾向がある。従って、金属シリコン含有量は0.1〜1質量%とする。金属シリコン源としては、金属シリコン粉末の他、Al−Si合金粉末の形態で、同じ質量のシリコンを添加してもほぼ同様の効果が得られる。 When metal silicon is added together with metal aluminum, the reactivity of the generated carbide (Al 4 SiC 4 ) with water is lower than that of aluminum carbide (Al 4 C 3 ), so that reaction with cooling water 18 during drilling is performed. It is possible to suppress damage to the perforating brick 6a. If the metal silicon content is less than 0.1% by mass, the effect of suppressing the formation of aluminum carbide is not sufficient, so that the wear rate of the new bottom blowing tuyere 1a is sufficiently increased due to the reaction with the cooling water 18 during drilling. Cannot be suppressed. On the other hand, even if the metal silicon content is increased from 1% by mass, the effect of suppressing wear is not improved, but rather the corrosion resistance tends to decrease. Therefore, the metal silicon content is 0.1 to 1% by mass. As the metal silicon source, in addition to the metal silicon powder, Al-Si alloy powder is used in the form of Al-Si alloy powder.

また、金属シリコン含有量と金属アルミニウム含有量の質量比(金属シリコン質量/金属アルミニウム質量)は、0.1〜0.4の範囲とすることが望ましい。なぜなら、0.1未満では、穿孔時の冷却水18との反応の影響による新たな底吹き羽口1aの損耗速度増大を十分に抑制できない。一方、0.4よりも大きくしてもさらに損耗抑制効果が向上する訳ではなく、むしろ耐食性が低下する傾向があるからである。   Further, the mass ratio of the metal silicon content to the metal aluminum content (metal silicon mass / metal aluminum mass) is desirably in the range of 0.1 to 0.4. This is because if the ratio is less than 0.1, an increase in the wear rate of the new bottom blowing tuyere 1a due to the influence of the reaction with the cooling water 18 during drilling cannot be sufficiently suppressed. On the other hand, even if it exceeds 0.4, the wear suppression effect does not improve further, but rather the corrosion resistance tends to decrease.

なお、穿孔用煉瓦6aの上記成分以外の成分として、ホウ素などを添加することができ、残部はマグネシアである。   In addition, boron etc. can be added as components other than the said component of the brick 6a for a hole, and the remainder is magnesia.

前記穿孔用煉瓦の穿孔は、煉瓦の温度が低下してから実施すると、穿孔時の冷却水18による影響範囲が拡大して新たな底吹き羽口1aの損耗速度が増大する、おそれがある。このため、穿孔前の最後の転炉吹錬を終了した後、できるだけ早く実施することが望ましく、遅くとも20時間以内に行うようにすることが望ましい。なぜなら、20時間を超えると、煉瓦が冷却されるとともに熱膨張が収まり、施工周辺の目地開きが発生してビット冷却用の水が穿孔範囲外へ流出することによって、炉体の煉瓦が損傷される、おそれがあるためである。   If the perforating brick is perforated after the temperature of the brick is lowered, there is a possibility that the range of influence by the cooling water 18 during perforation is expanded and the wear rate of the new bottom blowing tuyere 1a is increased. For this reason, after finishing the last converter blowing before drilling, it is desirable to carry out as soon as possible, and it is desirable to carry out within 20 hours at the latest. This is because if it exceeds 20 hours, the brick is cooled and the thermal expansion is stopped, joint opening around the construction occurs, and the water for bit cooling flows out of the perforation range, and the brick of the furnace body is damaged. This is because there is a risk.

また、穿孔用煉瓦の温度条件としては、穿孔用ベース煉瓦の平均温度が500℃以上であるうちに穿孔を開始することが望ましい。なぜなら、500℃未満になると、ビット冷却用の水が穿孔範囲以外へ流入し、炉体の煉瓦が損傷される、おそれがあるためである。
通常は、数本の底吹き羽口を新たに設置する場合でも、最後の転炉吹錬終了から6時間程度以内で穿孔作業を実施でき、穿孔用煉瓦の平均温度も650℃以上で穿孔を開始することができる。
Further, as a temperature condition of the perforating brick, it is desirable to start perforating while the average temperature of the perforating base brick is 500 ° C. or higher. This is because when the temperature is lower than 500 ° C., water for cooling the bit flows out of the perforation range, and the brick of the furnace body may be damaged.
Normally, even when several bottom-blown tuyere are newly installed, the drilling can be carried out within about 6 hours from the end of the final converter blowing, and the average temperature of the drilling brick is 650 ° C or higher. Can start.

このようにして、穿孔用煉瓦6aや周辺のワーク煉瓦12を傷付けたり、又必要以上に貫通孔8が大きくなるなどの不具合を発生させることなく、穿孔用煉瓦6aの中心部に所定の穿孔方向に沿って短時間のうちに穿孔して貫通孔8を形成すれば、底吹き羽口を熱間にて確実に設置することができる。その結果、新しい底吹き羽口の損耗速度が転炉稼動時から使用していた底吹き羽口の損耗速度と同等となり、炉体寿命末期まで適切な底吹き羽口数を確保されるため、転炉の精錬反応が炉体寿命末期まで効率化され、鉄歩留まりの向上および合金鉄原単位の低減など、転炉生産性の向上が達成される。   In this way, a predetermined drilling direction is provided at the center of the drilling brick 6a without causing damage to the drilling brick 6a or the surrounding work brick 12 or causing the through-hole 8 to become larger than necessary. If the through-hole 8 is formed by drilling in a short time along the bottom, the bottom blowing tuyere can be reliably installed in the hot. As a result, the wear rate of the new bottom blowing tuyere is equivalent to the wear rate of the bottom blowing tuyere that has been used since the operation of the converter, and the appropriate number of bottom blowing tuyere is secured until the end of the furnace life. The refining reaction of the furnace is made efficient until the end of the life of the furnace body, and improvement in converter productivity is achieved, such as improvement in iron yield and reduction in iron alloy basic unit.

なお、本発明は上記したところに限定されるものではなく種々の変更が可能である。例えば、ベース煉瓦7を設置しているが、ベース煉瓦7を設置せず、羽口受け煉瓦となる穿孔用煉瓦6aをフランジ蓋13と接触させて配置してもよく、また、複数層のワーク煉瓦12を配置してもよい。さらに、ArガスやN2 ガスなどの攪拌用ガスを吹込むための複数の金属細管を集合させた底吹き羽口の例について説明したが、これには限定されず、単管の羽口やO2 ガスと冷却用ガスを吹込むための2重管羽口の場合にも適用可能である。単管羽口の場合には、これを被覆する羽口煉瓦とともに貫通孔8に挿入して、新たな底吹き羽口を形成することが望ましいが、2重管羽口の場合には、2重管を直接貫通孔8に挿入し、隙間に耐火モルタルを充填することが望ましい。これにより強冷却される2重管外面の先端付近の羽口煉瓦に発生する熱応力を緩和して、羽口寿命を向上することができる。 In addition, this invention is not limited to the above place, A various change is possible. For example, although the base brick 7 is installed, the base brick 7 may not be installed, and the drilling brick 6a serving as the tuyere receiving brick may be arranged in contact with the flange lid 13, or a plurality of layers of work Brick 12 may be arranged. Furthermore, although an example of a bottom blowing tuyere in which a plurality of metal thin tubes for injecting a stirring gas such as Ar gas or N 2 gas has been described, the present invention is not limited to this, and a single tuyere tuyere or O 2 The present invention is also applicable to a double tube tuyere for blowing gas and cooling gas. In the case of a single tube tuyere, it is desirable to form a new bottom-blown tuyere by inserting it into the through-hole 8 together with tuyere bricks that cover it. It is desirable to insert the heavy pipe directly into the through hole 8 and fill the gap with refractory mortar. Thereby, the thermal stress generated in the tuyere brick near the tip of the outer surface of the double pipe that is strongly cooled can be relieved and the tuyere life can be improved.

本発明に係る転炉底吹き羽口の熱間設置方法について、350t規模の転炉において実施して種々の評価を行った。高炉から出銑した溶銑と溶銑に対して10質量%程度のスクラップを転炉に装入して、図1に示した底吹き羽口6個からアルゴンガスまたは窒素ガスを0.05〜0.15Nm/min・tで吹込みながら、脱炭吹錬を繰り返し行った。その際、レーザープロフィール測定装置を用いて、数百チャージの吹錬回数を挟んで間欠的に各羽口の残厚を測定し、損耗速度を評価するとともに、羽口の寿命判定を行った。 About the hot installation method of the converter bottom blowing tuyeres concerning this invention, it implemented in the 350t scale converter, and performed various evaluation. The molten iron discharged from the blast furnace and a scrap of about 10% by mass with respect to the molten iron are charged into the converter, and argon gas or nitrogen gas is added to the bottom blowing tuyere shown in FIG. Decarburization blowing was repeatedly performed while blowing at 15 Nm 3 / min · t. At that time, using a laser profile measuring device, the remaining thickness of each tuyere was measured intermittently across the number of blows of several hundred charges, the wear rate was evaluated, and the life of the tuyere was determined.

そして、羽口の残厚が所定値(パーマネント煉瓦の表面から100mm)に達したならば、羽口の使用を停止して損耗部位を不定形耐火物で補修するとともに、上述した図2および3に示したところの、本発明の底吹き羽口の熱間設置方法に従って、予め炉底に設置しておいた6個の穿孔用煉瓦6aに新たな底吹き羽口を設置した。すなわち、羽口を使用停止して準備作業を行った後、直前の最終吹錬終了後2〜3時間で穿孔を開始した。その時点での穿孔用煉瓦の平均温度は、表面温度の測定値と伝熱計算の結果によれば、何れの場合にも700℃以上であった。穿孔用煉瓦は、材質の異なる数種類の穿孔用煉瓦を用意した。   When the remaining thickness of the tuyere reaches a predetermined value (100 mm from the surface of the permanent brick), the use of the tuyere is stopped and the worn part is repaired with an irregular refractory, and the above-described FIGS. In accordance with the method for hot installation of bottom blowing tuyeres according to the present invention, new bottom blowing tuyere were installed on the six drilling bricks 6a previously installed on the furnace bottom. That is, after the use of the tuyere was stopped and preparatory work was performed, drilling was started 2-3 hours after the end of the last final blowing. The average temperature of the perforated brick at that time was 700 ° C. or higher in any case according to the measured surface temperature and the heat transfer calculation result. Several types of drilling bricks with different materials were prepared.

次いで、6箇所の羽口を熱間で設置した後、炉内にコークスを投入し、酸素を上吹きして炉内の予熱を行い、その後前記と同様にして脱炭吹錬を繰り返し行った。表1に、用いた穿孔用煉瓦の組成と熱間で設置した羽口の損耗速度を示す。また参考例として、初期に設置した羽口の羽口ブロック煉瓦6の組成と、初期に設置した羽口の損耗速度についても併記した。   Next, after installing six tuyere hot, coke was put into the furnace, oxygen was blown up to preheat the furnace, and then decarburization blowing was repeated in the same manner as described above. . Table 1 shows the composition of the drilling bricks used and the wear rate of the tuyere installed hot. As a reference example, the composition of the tuyere block brick 6 of the tuyere installed in the initial stage and the wear rate of the tuyere installed in the initial stage are also shown.

発明例と参考例とを比較すると、本発明の方法により熱間で設置した羽口の損耗速度は、初期に設置した羽口の損耗速度と同等であることが判る。一方、金属シリコンを含まない穿孔用煉瓦を用いた比較例1では、発明例に比べて損耗速度が大幅に増大している。
ここで、比較例1と参考例2との比較から、この材質では熱間で設置した羽口の損耗速度が、初期に設置した羽口の損耗速度に比べて大幅に増大しているが、このことは、この煉瓦材質は穿孔時の冷却水の影響で損傷し易いことを示している。参考例3は、冷却水の影響を受け難い、金属アルミニウム含有量を低減した材質の例であるが、高温強度が低下するため、初期に設置した羽口においても損耗速度が大きい。
ちなみに、発明例において金属Si/金属Alが0.1〜0.4である発明例1〜3並びに同5〜8は、発明例4と比較して羽口の損耗速度が小さい。
Comparing the inventive example and the reference example, it can be seen that the wear rate of the tuyere installed hot by the method of the present invention is equivalent to the wear rate of the tuyere installed in the initial stage. On the other hand, in Comparative Example 1 using a perforating brick that does not contain metallic silicon, the wear rate is significantly increased as compared with the inventive example.
Here, from the comparison between Comparative Example 1 and Reference Example 2, in this material, the wear rate of the tuyere installed hot is greatly increased compared to the wear rate of the tuyere installed initially, This indicates that this brick material is easily damaged by the influence of cooling water during drilling. Reference Example 3 is an example of a material that is hardly affected by the cooling water and has a reduced metal aluminum content. However, since the high-temperature strength is reduced, the wear rate is high even in the tuyere that is initially installed.
Incidentally, in the inventive examples, Invention Examples 1 to 3 and 5 to 8 in which the metal Si / metal Al is 0.1 to 0.4 have a lower tuyere wear rate than the Invention Example 4.

また、穿孔用煉瓦の炭素量が低い比較例2、金属Al量の低い比較例3、そして金属Al量の多い比較例4はいずれも、損耗速度が上昇した。さらに、金属Si量の多い比較例5は、熱間強度が低いために損耗速度が上昇した。
さらに、給水を行わずに施工を行った比較例6では、穿孔時にビットの振動が大きくなり、穿孔した貫通孔と新たに設置した羽口煉瓦との隙間が大きくなり、損耗速度が上昇した。コアビットのセグメントに炭素鋼を用いた比較例7は穿孔時に周囲耐火煉瓦に隙間が生じたため羽口の損耗速度が上昇した。また、比較例8では羽口設置後、新たに設置した羽口周囲の煉瓦の損耗速度が大きくなり、羽口の損耗速度も上昇した。
Further, in Comparative Example 2 in which the carbon content of the perforated brick was low, Comparative Example 3 in which the amount of metallic Al was low, and Comparative Example 4 in which the amount of metallic Al was large, the wear rate increased. Furthermore, in Comparative Example 5 having a large amount of metallic Si, the wear rate increased because the hot strength was low.
Further, in Comparative Example 6 in which construction was performed without water supply, the vibration of the bit increased during drilling, the gap between the drilled through hole and the newly installed tuyere brick increased, and the wear rate increased. In Comparative Example 7 in which carbon steel was used for the core bit segment, the wear rate of the tuyere increased because a gap occurred in the surrounding refractory bricks during drilling. In Comparative Example 8, after the tuyere was installed, the wear rate of the newly installed bricks around the tuyere increased, and the wear rate of the tuyere increased.

以上に示したように、本発明の底吹き羽口の熱間設置方法によれば、水冷によって穿孔工具の耐久性を確保しつつ、穿孔用煉瓦の中心部を所定の穿孔方向に沿って短時間のうちに精度良く穿孔して貫通孔を形成すると共に、穿孔後に設置する羽口煉瓦および穿孔用煉瓦を穿孔した羽口受け煉瓦の寿命が低下することを防止できる。上記の説明では、6本の底吹き羽口を一度に全て切替える場合について示したが、本発明の方法では比較的短時間で羽口を設置できるので、羽口の損耗状況に応じて、1度に1本ずつの羽口を追加して設置する方法であっても良い。   As described above, according to the hot installation method of the bottom blow tuyere of the present invention, the center portion of the drilling brick is shortened along a predetermined drilling direction while ensuring the durability of the drilling tool by water cooling. It is possible to prevent the life of the tuyere receiving bricks perforated from the tuyere bricks and the perforating bricks installed after the drilling from being drilled with precision with time to form through holes. In the above description, the case where all of the six bottom blowing tuyere are switched at a time has been shown. However, since the tuyere can be installed in a relatively short time in the method of the present invention, 1 A method may be used in which one tuyere is added and installed each time.

Figure 2013245384
Figure 2013245384

本発明によれば、穿孔用煉瓦および周辺部のワーク煉瓦に損傷を与えることなく、穿孔用煉瓦の中心部に所定の穿孔方向に沿って短時間のうちに貫通孔を穿孔して底吹き羽口を熱間で設置することが可能となり、熱間で設置した羽口の寿命低下も防止できる。その結果、耐火物費用を低減しつつ転炉の稼動率を向上できるとともに、底吹き羽口を転炉の稼動期間全体にわたって健全に保つことができるため、転炉生産性の向上や鉄歩留まりの向上など産業上の利用価値が高い。   According to the present invention, the bottom blowing blade is formed by drilling a through hole in a short time along a predetermined drilling direction in the center of the drilling brick without damaging the drilling brick and the peripheral work brick. The mouth can be installed hot, and the life of the tuyere installed hot can be prevented. As a result, the operating rate of the converter can be improved while reducing the cost of refractories, and the bottom blowing tuyere can be kept healthy throughout the operating period of the converter, improving the converter productivity and the iron yield. Industrial value such as improvement is high.

1 底吹き羽口
1a 熱間設置用底吹き羽口
2 風箱
2a 熱間設置用底吹き羽口の風箱
3 ガス吹込用管
4 羽口煉瓦
5 ガス導入管
6 羽口ブロック煉瓦
6a 穿孔用煉瓦
7 ベース煉瓦
7a 穿孔用ベース煉瓦
8 穿孔用煉瓦に形成した貫通孔
10 鉄皮
100 フランジ
11 永久煉瓦
12 ワーク煉瓦
13 羽口押えフランジ蓋
13a フランジ蓋
14 羽口押え煉瓦
14a 押え煉瓦
15 コアビット
16 ダイヤモンドセグメント
17 コアドリル回転軸
18 冷却水
DESCRIPTION OF SYMBOLS 1 Bottom blowing tuyere 1a Bottom blowing tuyere for hot installation 2 Wind box 2a Wind box for bottom blowing tuyere for hot installation 3 Gas blowing pipe 4 Tuyere brick 5 Gas inlet pipe 6 Tuyere block brick 6a For drilling Brick 7 Base brick 7a Base brick for drilling 8 Through hole formed in brick for drilling 10 Iron skin
100 flange 11 permanent brick 12 work brick 13 tuyere presser flange lid 13a flange lid 14 tuyere presser brick 14a presser brick 15 core bit 16 diamond segment 17 core drill rotating shaft 18 cooling water

Claims (3)

転炉の底部を覆う耐火物層内における、底吹き羽口の設置部位以外の部分に、予め穿孔用煉瓦を配置し、該転炉の使用経過後に前記穿孔用煉瓦に新たな底吹き羽口を設置するに当たり、
前記穿孔用煉瓦として、金属アルミニウム:0.5〜3質量%、金属シリコン:0.1〜1質量%および炭素:15〜25質量%を含有するマグネシアカーボン煉瓦を配置し、前記底部の外側から前記穿孔用煉瓦に対して、硬質セグメントを備えるコアビットにて、該コアビットの先端に給水しつつ穿孔を行って、前記穿孔用煉瓦に前記耐火物層を貫通する孔を形成し、該貫通孔に、新たな転炉底吹き羽口を挿入することを特徴とする転炉底吹き羽口の熱間設置方法。
In the refractory layer covering the bottom of the converter, a drilling brick is previously placed in a portion other than the installation site of the bottom blowing tuyere, and a new bottom blowing tuyere is added to the drilling brick after the use of the converter. When installing
As the perforating brick, a magnesia carbon brick containing metal aluminum: 0.5-3 mass%, metal silicon: 0.1-1 mass% and carbon: 15-25 mass% is arranged, from the outside of the bottom. With respect to the drilling brick, the core bit having a hard segment is drilled while supplying water to the tip of the core bit to form a hole penetrating the refractory layer in the drilling brick. A method for hot installation of a converter bottom blowing tuyere characterized by inserting a new converter bottom blowing tuyere.
前記穿孔用煉瓦に対する穿孔は、該穿孔前の前記転炉における最後の吹錬終了から20時間以内に行うことを特徴とする請求項1に記載の転炉底吹き羽口の熱間設置方法。   The method for hot installation of a converter bottom blowing tuyere according to claim 1, wherein the drilling of the brick for drilling is performed within 20 hours from the end of the last blowing in the converter before the drilling. 前記穿孔用煉瓦の穿孔開始時の温度が500℃以上であることを特徴とする請求項1または請求項2に記載の転炉底吹き羽口の熱間設置方法。   The method for hot installation of a converter bottom blowing tuyeres according to claim 1 or 2, wherein the temperature at the start of drilling of the brick for drilling is 500 ° C or higher.
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