JPS6224489B2 - - Google Patents
Info
- Publication number
- JPS6224489B2 JPS6224489B2 JP59196542A JP19654284A JPS6224489B2 JP S6224489 B2 JPS6224489 B2 JP S6224489B2 JP 59196542 A JP59196542 A JP 59196542A JP 19654284 A JP19654284 A JP 19654284A JP S6224489 B2 JPS6224489 B2 JP S6224489B2
- Authority
- JP
- Japan
- Prior art keywords
- blowing
- tuyere
- tuyeres
- gas
- wear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000007664 blowing Methods 0.000 claims description 56
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 37
- 229910052742 iron Inorganic materials 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 8
- 238000009628 steelmaking Methods 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000007789 gas Substances 0.000 description 29
- 229910000831 Steel Inorganic materials 0.000 description 15
- 239000011261 inert gas Substances 0.000 description 15
- 239000010959 steel Substances 0.000 description 15
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 238000007670 refining Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 239000011819 refractory material Substances 0.000 description 4
- 230000003628 erosive effect Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- -1 N 2 or Ar Chemical compound 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Landscapes
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
製鋼用転炉における精錬反応特性の向上を目的
として、吹錬中の溶鉄浴中に気体、就中、不活性
ガスの吹き込みを行う転炉の操業において、該気
体の吹き込みに供する羽口の寿命延伸を、精錬特
性の改善にあわせ成就する羽口の保護方法に関連
してこの明細書で述べる技術内容は、転炉複合吹
錬法の改良の一環に位置づけられる。[Detailed Description of the Invention] (Industrial Application Field) A converter for blowing gas, especially an inert gas, into a molten iron bath during blowing for the purpose of improving the refining reaction characteristics in a steelmaking converter. The technical content described in this specification relates to a method for protecting the tuyeres used for blowing the gas in the operation of the converter, which achieves the extension of the life of the tuyeres used for blowing the gas together with the improvement of the refining characteristics. It is positioned as part of the improvement.
（従来の技術）
転炉製鋼においては、炭化水素で保護された羽
口を用いる酸素底吹き転炉の出現以来、吹錬中の
鋼浴の撹拌を強化することが、鉄歩止りの向上な
ど転炉の治金特性の著しい向上に寄与することが
明らかとなつた。(Prior art) In converter steelmaking, since the advent of oxygen bottom-blown converters that use hydrocarbon-protected tuyeres, it has been important to enhance the agitation of the steel bath during blowing to improve iron yield, etc. It has become clear that this contributes to a significant improvement in the metallurgical properties of converters.
この解明に基づいて上吹きランスから酸素を供
給するLD転炉においても、吹錬中の溶鉄浴中に
各種のガスを吹き込み鋼浴の撹拌の強化を計るこ
と、つまり複合吹錬法の開発が触発され実操業に
おいて普及しつつある。この間の事情は、例えば
鉄と鋼、1983年voL.69P.24に詳述されている。 Based on this understanding, even in the LD converter where oxygen is supplied from the top blowing lance, various gases are injected into the molten iron bath during blowing to strengthen the stirring of the steel bath, that is, the development of the combined blowing method. It is becoming popular in actual operations. The circumstances during this time are detailed in, for example, Tetsu to Hagane, 1983 voL.69P.24.
ところが、従来この種の羽口として金属製のパ
イプすなわち単管、又は多数の細孔を有する耐火
物よりなるいわゆるポーラスプラグが用いられて
いたが、何れの場合も、転炉の炉底耐火物とくら
べて、一般に羽口の耐用寿命がより短い。羽口は
通常転炉の炉底の耐火物と一体構造をなすため該
耐火物が未だ耐用寿命に達していないにもかかわ
らず、羽口がよく速り耐用寿命に達して炉体交換
時期を決定づける不利が余儀なくされた。 However, as this type of tuyeres, metal pipes, i.e., single tubes, or so-called porous plugs made of refractories with many pores have been used in the past, but in both cases, the refractories at the bottom of the converter In comparison, the service life of tuyeres is generally shorter. The tuyere is usually integrated with the refractory at the bottom of the converter, so even though the refractory has not yet reached the end of its useful life, the tuyeres quickly reach the end of their useful life and it is time to replace the furnace body. He was forced into a decisive disadvantage.
もちろん、羽口を閉塞して、撹拌気体の吹き込
みを停止して上吹きランスからの酸素のみで精錬
を行う操業継続は可能であつても、精錬特性の悪
化が伴われるのはいうまでもない。 Of course, even if it is possible to continue the operation by blocking the tuyeres, stopping the blowing of stirring gas, and performing refining using only oxygen from the top blowing lance, it goes without saying that this will result in deterioration of the refining characteristics. .
（発明が解決しようとする問題点）
このように、炉底耐火物に先行する羽口の溶損
を防止し、炉体の全体としての耐用寿命の延長を
可能にすることがこの発明の目的である。(Problems to be Solved by the Invention) As described above, the purpose of the present invention is to prevent melting of the tuyeres preceding the bottom refractory and to extend the service life of the furnace body as a whole. It is.
（問題点を解決するための手段）
発明者らは金属製パイプよりなる羽口の溶損に
ついて、吹錬中における羽口の溶損速度を測定す
る次の手法を開発し、それによつて羽口溶損の対
策を研究した。(Means for Solving the Problem) The inventors have developed the following method for measuring the erosion rate of the tuyeres made of metal pipes during blowing. We researched measures to prevent mouth erosion.
すなわち吹錬中の羽口の損耗速度を電気パルス
反射法により測定することである。 That is, the wear rate of the tuyere during blowing is measured by electric pulse reflection method.
ここに羽口の軸心に沿つて炉底耐火物中に、耐
火性の同軸ケーブルを埋め込み、電気パルスの反
射から同軸ケーブルの長さを吹錬中逐次に求め
た。この同軸ケーブルは羽口と同一速度で損耗
し、従つて吹錬中の羽口の損耗速度の計測に利用
できる。 A refractory coaxial cable was embedded in the bottom refractory along the axis of the tuyere, and the length of the coaxial cable was determined sequentially during blowing from the reflection of electric pulses. This coaxial cable wears out at the same rate as the tuyeres and can therefore be used to measure the rate of wear of the tuyeres during blowing.
この測定を行つた結果、羽口は吹錬中を通じて
一定速度で損耗するのではなくして、とくに、吹
錬の後半で溶鋼の温度が1500℃以上といつた高温
で、しかも、溶鋼中の炭素濃度が約1.0％以下と
いつた領域においてとくに溶損速度が大となるこ
とがわかつた。 As a result of this measurement, it was found that the tuyeres do not wear out at a constant rate throughout the blowing process, but that the tuyere wears out at a constant rate during the blowing process. It was found that the erosion rate was particularly high in the region where the concentration was about 1.0% or less.
溶鉄浴の温度が高くなると羽口の損耗速度が大
となるのは、羽口周囲の耐火物あるいは羽口自身
への熱負荷が増大するためと考えられる。 The reason why the rate of wear of the tuyeres becomes faster as the temperature of the molten iron bath increases is thought to be because the heat load on the refractories around the tuyeres or on the tuyere itself increases.
一方溶鉄浴中の炭素濃度が1.0％以下で損耗速
度が大となる理由については、鋼浴中の炭素濃度
の抵下につれて、鋼浴中に懸濁する酸化鉄の量が
増し（なんとなれば浴表面からランスを介して浴
面に吹きつけられる純酸素ガスは鋼浴と反応して
まずFeOを生成し、このFeOが浴中のＣと反応し
て、FeO＋Ｃ→CO＋Feとなる反応で脱炭が進行
し、このため、Ｃの濃度が低下すると、FeOの環
元が十分な速度で進まなくなり浴中に懸濁する
FeOが増加する。）、この酸化鉄が羽口周囲の耐火
物と反応して耐火物の融点を低下したり、耐火物
中の炭素分と反応して耐火物を脱炭したりして、
羽口を損耗させるものと考えられる。 On the other hand, the reason why the wear rate increases when the carbon concentration in the molten iron bath is 1.0% or less is that as the carbon concentration in the steel bath decreases, the amount of iron oxide suspended in the steel bath increases. Pure oxygen gas, which is blown onto the bath surface through a lance, reacts with the steel bath and first produces FeO, which then reacts with C in the bath to form FeO+C→CO+Fe, resulting in decarburization. As a result, when the concentration of C decreases, the ring element of FeO does not proceed at a sufficient speed and becomes suspended in the bath.
FeO increases. ), this iron oxide reacts with the refractory around the tuyere to lower the melting point of the refractory, or reacts with the carbon content in the refractory to decarburize the refractory.
This is thought to cause wear and tear on the tuyeres.
以上の知見に基づき、吹錬末期の羽口の損耗速
度が大となる時期の羽口の損耗の防止方法につい
て研究を進めた結果、羽口の損耗が大となる時期
に、羽口を通じて鋼浴中に吹き込む撹拌気体の羽
口入側の圧力を40Kgｆ／cm2以上といつた高圧にす
ると、羽口の損耗が著しく軽減されることが見出
された。以上の知見に基づいてこの発明は製鋼用
転炉の底部に設けた金属管羽口から該転炉内の溶
鉄中に気体を吹き込み、溶鉄の撹拌を行う際、該
転炉における吹錬後半で溶鉄温度が上昇し、炭素
濃度が低下した時期に、羽口を通じて吹き込む上
記気体の圧力を40Kgｆ／cm2以上に昇圧することか
らなる製鋼用転炉の羽口の保護方法を確立したも
のである。 Based on the above knowledge, we conducted research on methods to prevent tuyere wear at the end of the blowing period, when the wear rate of the tuyere is high. It has been found that when the pressure of the stirring gas blown into the bath at the inlet side of the tuyere is set to a high pressure of 40 Kgf/cm 2 or more, wear and tear on the tuyere is significantly reduced. Based on the above knowledge, this invention injects gas into the molten iron in the converter from the metal tube tuyere provided at the bottom of the converter for steelmaking, and when stirring the molten iron, during the latter half of blowing in the converter. This method has been established to protect the tuyere of a steelmaking converter, which involves increasing the pressure of the above gas injected through the tuyere to 40Kgf/ cm2 or higher when the molten iron temperature rises and the carbon concentration decreases. .
（作用）
撹拌気体の吹き込みを高圧とすることで羽口の
損耗が著しく軽減される理由について、種々の調
査を行つたところ、以下の二つの理由が解明され
た。(Function) As a result of various investigations into the reason why the wear and tear on the tuyere is significantly reduced by blowing in stirring gas at high pressure, the following two reasons were clarified.
第１に、コールドモデル実験にて実炉と同一の
羽口により水中で空気を噴射し、羽口周辺の水の
流動状況を観察したところ、空気圧力を40Kgｆ／
cm2以上の高圧とすると、空気が水中で安定したガ
スジエツトを形成し、羽口周辺にて耐火物と接す
る部分の局所的な水の流動が非常に小となり、耐
火物の損耗に有利な条件となることが明らかとな
つた。 First, in a cold model experiment, air was injected into the water using the same tuyere as in the actual reactor, and the flow of water around the tuyere was observed.
When the pressure is set to a high pressure of cm 2 or more, air forms a stable gas jet in the water, and the local flow of water in the area around the tuyeres in contact with the refractory becomes very small, creating conditions favorable for wear and tear on the refractory. It became clear that.
ところが、圧力を20Kgｆ／cm2以下といつた低圧
とすると、羽口から噴出するガスジエツトは不安
定なジエツトとなり、羽口周辺の耐火物と接する
部分の局所的な水の動きが激しくなり、耐火物の
損耗に不利な条件となることが明らかとなつた。 However, if the pressure is set to a low pressure of 20 kgf/cm 2 or less, the gas jet ejected from the tuyere becomes an unstable jet, and the local water movement around the tuyere in contact with the refractory material increases, causing the fire resistance to deteriorate. It has become clear that this is a disadvantageous condition for the wear and tear of objects.
羽口周辺の耐火物面と接する溶鋼の流動が激し
ければ耐火物の損耗に不利なことは当然である
が、この現象は特に溶鋼中に懸濁するFeO粒が多
い時に顕著となるものと考えられる。 It is natural that intense flow of molten steel in contact with the refractory surface around the tuyere is detrimental to the wear of the refractory, but this phenomenon is particularly noticeable when there are many FeO particles suspended in the molten steel. Conceivable.
第２には、実炉にて溶鉄浴と接する耐火物面か
ら50mm離れた位置にて羽口の温度を熱電対で、吹
錬中を通じて測定したところ、通常は吹錬の経過
（つまり鋼浴温度の上昇）につれて羽口温度は上
昇するが、吹錬途中で羽口から吹き込む気体の圧
力を40Kgｆ／cm2以上と高圧すると、羽口温度が急
激に低下することが明らかとなつた。 Second, when we measured the temperature of the tuyere with a thermocouple at a position 50 mm away from the refractory surface in contact with the molten iron bath during blowing in an actual furnace, we found that It has become clear that the tuyere temperature rises as the temperature rises), but if the pressure of the gas blown from the tuyere is increased to 40 Kgf/cm 2 or higher during blowing, the tuyere temperature drops rapidly.
これに反し吹込み圧力を変更しないで吹錬終了
まで、20Kgｆ／cm2下の低圧で吹き込み続けると、
羽口温度は吹錬末期まで単調に上昇し続けること
が明らかとなつた。 On the other hand, if you continue blowing at a low pressure of 20Kgf/ cm2 until the end of blowing without changing the blowing pressure,
It became clear that the tuyere temperature continued to rise monotonically until the end of blowing.
この点においても吹錬末期に撹拌気体の圧力を
増大すると、羽口の温度が低下し羽口の損耗に有
利なことが明らかとなつた。 In this respect as well, it has become clear that increasing the pressure of the stirring gas at the end of blowing lowers the temperature of the tuyere, which is advantageous in terms of wear and tear on the tuyere.
ここに、圧力を上昇すると羽口の温度が低下す
る理由は、気体による羽口の冷却効果つまり、吹
き込み圧力が高いと、羽口部での圧力降下が大き
く気体の膨張によるガス温度の低下に基づくもの
と解釈される。 The reason why the temperature at the tuyere decreases when the pressure increases is due to the cooling effect of the gas on the tuyere.In other words, when the blowing pressure is high, the pressure drop at the tuyere is large and the gas temperature decreases due to the expansion of the gas. be interpreted as based on
以上のように、この発明の特徴は羽口の損耗が
大となる時期ならびにその有効な抑制についての
究明結果に基づいて、40Kgｆ／cm2以上といつた高
圧気体を用い上記した時期における羽口の損耗を
有利に防止できるところにあり、羽口の直径を大
として単にガス流量を増大することでは達成でき
ないことは、前述のコールドモデル実験結果のジ
エツトの挙動および羽口内でのガス圧力降下によ
るガス膨張によるガス温度低下から明らかであ
る。 As mentioned above, the feature of this invention is based on the research results regarding the period when tuyere wear and tear is large and its effective suppression. This cannot be achieved by simply increasing the gas flow rate by increasing the diameter of the tuyere, but is due to the behavior of the jet and the gas pressure drop within the tuyere as shown in the cold model experiment results described above. This is evident from the decrease in gas temperature due to gas expansion.
（実施例）
公称能力150トンの転炉において、その炉底に
内径５mmのステンレス鋼管からなる羽口を６本設
置し、この羽口からArあるいはN2ガスを吹き込
むようにした。(Example) In a converter with a nominal capacity of 150 tons, six tuyeres made of stainless steel pipes with an inner diameter of 5 mm were installed at the bottom of the furnace, and Ar or N 2 gas was blown into the tuyeres.
溶銑約160トンとスクラツプ約10トンを装入し
通常の方法で上吹きランスから酸素ガスを供給し
て炭素濃度が0.03〜0.08％まで脱炭吹錬を行つ
た。 Approximately 160 tons of hot metal and approximately 10 tons of scrap were charged, and oxygen gas was supplied from a top blowing lance to perform decarburization blowing to a carbon concentration of 0.03 to 0.08%.
この吹錬において、この発明に従い、炭素濃度
が0.5〜1.0％で溶鋼温度が1460〜1540℃となる酸
素供給量約42Nm3／ｔ・steelを境として、吹錬開
始から42Nm3／ｔ・steelの酸素供給量に至る期間
は、羽口からの不活性ガスの圧力を５〜14Kgｆ／
cm2とし、ガス流量を溶鋼１トン当り0.02〜0.06N
m3／minとし、42Nm3／ｔ・steelから吹錬終了
（酸素供給量で約55Nm3／ｔ・steel）までの期間
は、羽口保護のために不活性ガス圧力を40〜50Kg
ｆ／cm2とし、ガス流量を溶鋼１トン当り0.16〜
0.20Nm3／minとした。 In this blowing, according to the present invention, the oxygen supply amount is about 42Nm 3 /tsteel from the start of blowing, when the carbon concentration is 0.5 to 1.0% and the molten steel temperature is 1460 to 1540℃. During the period to reach the oxygen supply amount of
cm 2 , and the gas flow rate is 0.02 to 0.06N per ton of molten steel.
m 3 /min, and during the period from 42Nm 3 /t・steel to the end of blowing (approximately 55Nm 3 /t・steel with oxygen supply amount), the inert gas pressure is set at 40 to 50Kg to protect the tuyere.
f/cm 2 , and the gas flow rate is 0.16 to 1 ton of molten steel.
It was set to 0.20Nm 3 /min.
これに対し比較のため、ほぼ同一の条件で、羽
口からの不活性ガスの圧力を吹錬の全期間中を通
じて５〜14Kgｆ／cm2のほぼ一定値とし、したがつ
て、不活性ガス流量も溶鋼１トン当り0.02〜
0.06Nm3／minとして操業をおこなつた。 On the other hand, for comparison, under almost the same conditions, the pressure of the inert gas from the tuyere was kept at a nearly constant value of 5 to 14 Kgf/ cm2 throughout the entire blowing period, and therefore the inert gas flow rate was 0.02~ per ton of molten steel
The operation was carried out at 0.06Nm 3 /min.
以上の条件において、この発明の適用では不活
性ガス吹込み条件の実施率が吹錬回数の87％を占
める連続200チヤージの吹錬において、200チヤー
ジの吹錬の前後での羽口の損耗量を測定したとこ
ろ、１チヤージ当りの損耗量の平均値として0.45
mmなる値が得られた。一方、比較例の不活性ガス
吹込み条件の実施率が吹錬回数の82％（換言すれ
ばこの発明の不活性ガス吹込み条件の実施率が18
％）を占める連続94チヤージの吹錬において、94
チヤージの吹錬の前後で羽口の損耗量を測定した
ところ、１チヤージ当りの損耗量の平均値として
0.63mmなる値が得られた。 Under the above conditions, in the application of this invention, in continuous 200-charge blowing where the implementation rate of inert gas blowing conditions is 87% of the number of blowing, the amount of wear on the tuyere before and after 200-charge blowing is When measured, the average amount of wear per charge was 0.45
A value of mm was obtained. On the other hand, the implementation rate of the inert gas injection conditions in the comparative example was 82% of the number of blowing cycles (in other words, the implementation rate of the inert gas injection conditions of this invention was 18%).
%), in the blowing of 94 consecutive charges, 94
When we measured the amount of wear on the tuyere before and after blowing the charge, we found that the average value of the amount of wear per charge was
A value of 0.63 mm was obtained.
以上の実施例から明らかなように、この発明の
羽口の損耗速度は平均で0.45mm／チヤージであ
り、比較例の平均値0.63mm／チヤージと比べて、
羽口の損耗の防止効果に優れることが明らかであ
る。 As is clear from the above examples, the wear rate of the tuyere of the present invention is 0.45 mm/charge on average, compared to the average value of 0.63 mm/charge of the comparative example.
It is clear that the effect of preventing wear and tear on the tuyeres is excellent.
さらに前述とほぼ同一の実験条件下で、前述と
は異なつた構造の羽口を用いてこの発明の効果を
確認する実験を行つた。この実験では、内径が
1.5mm、外径が2.5mmの細径SUS304ステンレス鋼
管30本を円筒形の羽口レンガ内に均一に分散して
構成した、いわゆる多孔羽口を前述と同一の転炉
の炉底に４個設置した。前述の実施例と同じ条件
で、本発明の不活性ガス吹込み条件の実施率が吹
錬チヤージのうち74％を占める連続した345チヤ
ージの吹錬において、羽口の損耗量を測定したと
ころ、１チヤージ当りの平均値として0.36mmなる
値が得られた。一方、前述と同一の比較例の不活
性ガス吹込み条件の実施率が86％（換言すれば本
発明の不活性ガス吹込み条件の実施率が14％）を
占める連続した120チヤージの吹錬において羽口
の損耗速度を測定したところ、１チヤージ当りの
平均値として0.52mmなる値が得られた。 Further, under almost the same experimental conditions as described above, an experiment was conducted to confirm the effects of the present invention using a tuyere having a structure different from that described above. In this experiment, the inner diameter
Four so-called multi-hole tuyeres, each consisting of 30 small-diameter SUS304 stainless steel tubes of 1.5 mm and 2.5 mm outer diameter, uniformly dispersed within a cylindrical tuyere brick, were installed at the bottom of the same converter as mentioned above. installed. Under the same conditions as in the previous example, the amount of wear on the tuyeres was measured in continuous blowing of 345 charges in which the implementation rate of the inert gas blowing conditions of the present invention accounted for 74% of the blowing charges. An average value of 0.36 mm per charge was obtained. On the other hand, continuous 120-charge blowing in which the implementation rate of the inert gas blowing conditions of the same comparative example as mentioned above is 86% (in other words, the implementation rate of the inert gas blowing conditions of the present invention is 14%). When the wear rate of the tuyere was measured, an average value of 0.52 mm per charge was obtained.
この実施例においても本発明による羽口の損耗
速度は平均で0.36mm／チヤージであり、比較例の
平均値の0.52mm／チヤージと比べて、羽口の損耗
の防止効果に優れることが明らかである。 In this example as well, the wear rate of the tuyere according to the present invention was 0.36 mm/charge on average, which clearly shows that it is more effective in preventing wear of the tuyere than the average value of 0.52 mm/charge in the comparative example. be.
なお、吹錬の開始時から不活性ガスの圧力を40
Kgｆ／cm2以上の高圧として吹き込んでも上記実施
例とほぼ同等の羽口損耗防止効果が得られること
を前述と同様な実験で確認した。なおこの場合に
は、当然のことながら不活性ガスの使用量が多く
なり経済的でない。なんとなれば、一般に、不活
性ガスの吹込み目的は、吹錬の末期で炭素濃度が
1.0％以下と低下してきた時期に溶鋼の撹拌を強
化して鉄の過酸化を防止し、鉄源の歩止りを向上
することにあり、この観点から、経済的に羽口の
損耗を防止するためには、この発明のように、
1.0〜0.5％の炭素濃度で溶鋼温度が1500℃近くに
達した時点で撹拌気体の圧力を上昇することが得
策である。しかし、不活性ガスの吹込みの目的
は、吹錬後期の鉄の過酸化を防止するのみでな
く、吹錬前半から中期のスロツピングを防止する
ために用いられる場合もあり、この場合には吹錬
の全区間を通じて不活性ガス圧力を40Kg／cm2以上
とすることが経済的に可能となる。 In addition, from the start of blowing, the pressure of the inert gas is set to 40
It was confirmed through an experiment similar to the above that even when blowing at a high pressure of Kgf/cm 2 or more, the same effect of preventing tuyere wear as in the above example can be obtained. In this case, of course, the amount of inert gas used increases, which is not economical. Generally speaking, the purpose of inert gas blowing is to reduce the carbon concentration at the end of blowing.
The purpose is to prevent overoxidation of iron by strengthening the stirring of molten steel at a time when the iron content has decreased to 1.0% or less, and to improve the yield of the iron source.From this point of view, it is economically possible to prevent wear and tear of the tuyeres. In order, like this invention,
It is a good idea to increase the pressure of the stirring gas when the molten steel temperature reaches nearly 1500°C at a carbon concentration of 1.0 to 0.5%. However, the purpose of inert gas injection is not only to prevent overoxidation of the iron in the late stage of blowing, but also to prevent slopping in the early to middle stages of blowing. It is economically possible to maintain the inert gas pressure at 40 kg/cm 2 or higher throughout the entire refining section.
（発明の効果）
この発明によれば溶鉄浴中に吹込んで撹拌気体
の圧力に変更を加えることによつて、吹錬中に生
じる羽口の優先的な溶損を有効に抑制して、炉底
耐火物の損耗に揃えることができるので、炉体の
耐久性向上が撹拌強化による吹錬特性の向上にあ
わせ実現できる。(Effects of the Invention) According to the present invention, by changing the pressure of the stirring gas injected into the molten iron bath, preferential melting loss of the tuyeres that occurs during blowing can be effectively suppressed, and the furnace Since wear and tear of the bottom refractory can be compensated for, the durability of the furnace body can be improved at the same time as the blowing characteristics are improved due to stronger stirring.
なお、本発明はN2やArなどの溶鉄に対して完
全な不活性ガスのみに適用を限定されるわけでは
なく、CO2やCOガスあるいはこれらの混合ガ
ス、さらには、O2ガスを一部含有するガスにも
適用可能である。 Note that the present invention is not limited to application to gases that are completely inert to molten iron, such as N 2 or Ar, but can also be applied to CO 2 or CO gas, or a mixture thereof, or even O 2 gas. It can also be applied to gases containing
Claims (1)
転炉内の溶鉄中に気体を吹き込み、溶鉄の撹拌を
行う際、該転炉における吹錬後半で溶鉄温度が上
昇し、炭素濃度が低下した時期に、羽口を通じて
吹き込む上記気体の圧力を40Kgｆ／cm2以上に昇圧
することからなる製鋼用転炉の羽口の保護方法。1 When stirring the molten iron by blowing gas into the molten iron in the converter from the metal tube tuyeres installed at the bottom of the converter for steelmaking, the temperature of the molten iron rises in the latter half of blowing in the converter, and the carbon concentration increases. A method for protecting the tuyeres of a steelmaking converter, which comprises increasing the pressure of the gas injected through the tuyeres to 40 Kgf/cm 2 or more when the tuyeres are low.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19654284A JPS6176608A (en) | 1984-09-21 | 1984-09-21 | Method for protecting tuyere of converter for steel making |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19654284A JPS6176608A (en) | 1984-09-21 | 1984-09-21 | Method for protecting tuyere of converter for steel making |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6176608A JPS6176608A (en) | 1986-04-19 |
| JPS6224489B2 true JPS6224489B2 (en) | 1987-05-28 |
Family
ID=16359469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19654284A Granted JPS6176608A (en) | 1984-09-21 | 1984-09-21 | Method for protecting tuyere of converter for steel making |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6176608A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5420443A (en) * | 1977-07-15 | 1979-02-15 | Matsushita Electric Ind Co Ltd | High frequency heating device |
| JPS55158208A (en) * | 1979-05-24 | 1980-12-09 | Sumitomo Metal Ind Ltd | Refining method of steel |
-
1984
- 1984-09-21 JP JP19654284A patent/JPS6176608A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5420443A (en) * | 1977-07-15 | 1979-02-15 | Matsushita Electric Ind Co Ltd | High frequency heating device |
| JPS55158208A (en) * | 1979-05-24 | 1980-12-09 | Sumitomo Metal Ind Ltd | Refining method of steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6176608A (en) | 1986-04-19 |
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| LAPS | Cancellation because of no payment of annual fees |