JPS63143214A - Nitrogen adding method in converter having bottom blowing tuyere - Google Patents
Nitrogen adding method in converter having bottom blowing tuyereInfo
- Publication number
- JPS63143214A JPS63143214A JP28870486A JP28870486A JPS63143214A JP S63143214 A JPS63143214 A JP S63143214A JP 28870486 A JP28870486 A JP 28870486A JP 28870486 A JP28870486 A JP 28870486A JP S63143214 A JPS63143214 A JP S63143214A
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen
- molten steel
- blowing
- converter
- oxygen
- 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.)
- Granted
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 129
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 56
- 238000007664 blowing Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims description 20
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 36
- 239000010959 steel Substances 0.000 claims abstract description 36
- 239000001301 oxygen Substances 0.000 claims abstract description 30
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 30
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000007789 gas Substances 0.000 claims abstract description 10
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 20
- 238000005121 nitriding Methods 0.000 claims description 6
- 239000006185 dispersion Substances 0.000 abstract 3
- 230000003247 decreasing effect Effects 0.000 abstract 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 8
- 230000014759 maintenance of location Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910001021 Ferroalloy Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000002829 nitrogen Chemical class 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
Landscapes
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、底吹き羽口を有する転炉におい°ζ、高窒素
含有吹止め綱を溶製する方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for melting high nitrogen-containing blowstop steel in a converter having bottom-blown tuyeres.
〈従来の技術〉
最近、特許公開または公告された転炉での底吹き窒素ガ
スによる加窒方法として、■上下衣き転炉における溶鋼
（Ｈ）のコントロール法（特開昭５８−１６７７０８号
、）、 ■底吹き転炉精錬において吹止鋼の窒素含有量
を制御する方法（特公昭５８−３５２４４号）等がある
。<Prior art> As a nitrification method using bottom-blown nitrogen gas in a converter that has recently been patented or publicly announced, there is a method for controlling molten steel (H) in a converter with upper and lower jackets (Japanese Patent Application Laid-Open No. 167708/1989). ), (1) A method for controlling the nitrogen content of blowstop steel in bottom-blowing converter refining (Japanese Patent Publication No. 35244/1983), and so on.
前記Φの方法は、溶銑中の（Ｔｉ）レベルで推定される
溶銑中の（Ｎ）レベルによって底吹き窒素ガス量を決定
するものであり、■の方法は、溶鋼中炭素濃度が０．ｌ
Ｏ〜０．７０％の範囲にある間に酸素吹錬を止め、その
炭素濃度と目標吹止め（Ｎ）値により、決まる窒素ガス
量を吹込むことにより、高い窒素歩止りにて加窒するも
のである。The above method Φ determines the amount of bottom-blown nitrogen gas based on the (N) level in the hot metal estimated from the (Ti) level in the hot metal, and the method (2) determines the amount of nitrogen gas in the bottom blowing when the carbon concentration in the molten steel is 0. l
Oxygen blowing is stopped while the carbon concentration is in the range of 0 to 0.70%, and the amount of nitrogen gas determined by the carbon concentration and target blow-off (N) value is blown in to perform nitriding at a high nitrogen yield. It is something.
〈発明が解決しようとする問題点〉
前記■の方法では、溶銑成分、酸素吹錬条件、窒素ガス
吹込み時期や吹止め成分等により窒素溶解妻止りが変動
し、かつこの窒素歩止りを精度よく推定する方法がない
ため、目標の吹止め窒素１度を精度よく得ることは困難
であった。また、前記■の方法では、前記の炭素濃度範
囲（０，１０〜０．７０％）では、第３図に示すように
窒素溶解歩出りのバラツキが大きく、やはり目標の吹止
め窒素濃度に精度よく制御することは困難であった。<Problems to be Solved by the Invention> In the method (2) above, the nitrogen dissolution end point fluctuates depending on the hot metal composition, oxygen blowing conditions, nitrogen gas injection timing, blow-off component, etc., and this nitrogen yield cannot be controlled accurately. Since there is no way to accurately estimate the temperature, it has been difficult to accurately obtain the target blow-off nitrogen temperature of 1 degree. In addition, in the method (2) above, in the carbon concentration range (0.10 to 0.70%), there is a large variation in nitrogen dissolution rate as shown in Figure 3, and the target blow-off nitrogen concentration is still not reached. It was difficult to control accurately.
本発明はこのような問題点を解決し、目標の吹止め窒素
濃度を精度よく得るための底吹き羽口を有する転炉にお
ける加窒方法を提供することを目的とするものである。SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a method for nitriding in a converter having a bottom blowing tuyere for accurately obtaining a target blow-stop nitrogen concentration.
〈問題点を解決するための手段〉
発明者らは、ｔｓａｉ中の窒素濃度を精度よく制御する
方法について鋭意研究を重ねた結果、溶鋼中酸素濃度と
窒素掛止りとの間に特定の関係があるとの知見を得、こ
の知見にもとづいてこの発明をなすに至った。<Means for Solving the Problems> As a result of extensive research into methods for accurately controlling the nitrogen concentration in tsai, the inventors have found that there is a specific relationship between the oxygen concentration in molten steel and nitrogen retention. We have obtained the knowledge that there is, and based on this knowledge, we have come to make this invention.
本発明は、底吹き羽口を有する転炉で、窒素ガスあるい
は窒素を含む混合ガスを底吹き羽口より吹き込むことに
よって、溶鋼中の窒素濃度を制御する方法において、溶
鋼中酸素濃度が５０〜３００ｐｐｍの範囲で、その酸素
濃度と目標吹止め窒素濃度とに応じて、窒素ガスもしく
は窒素ガスを含む混合ガスを底吹きすることにより、吹
止め溶鋼中の窒素濃度を正確に制御する底吹き羽口を有
する転炉での加窒方法である。The present invention provides a method for controlling the nitrogen concentration in molten steel by blowing nitrogen gas or a mixed gas containing nitrogen through the bottom blowing tuyere in a converter having a bottom blowing tuyere. A bottom blower that accurately controls the nitrogen concentration in the blowstop molten steel by bottom blowing nitrogen gas or a mixed gas containing nitrogen gas within the range of 300 ppm depending on the oxygen concentration and the target blowstop nitrogen concentration. This is a nitriding method using a converter with a furnace.
く作 用〉
第４図に２３０を底吹き転炉における低炭素吹止鋼の通
常の窒素濃度の分布を示した０通常の吹止鋼においては
、その平均窒素濃度は１８．５ρｐｌ程度であり、出鋼
中の吸窒を考慮しても、取鍋での溶鋼中窒素濃度は２０
ｐｐｍ程度である。したがって、４０ｐｐｕ以上の高窒
素含有鋼の溶製には、■出鋼中あるいは鋳込中等に窒素
含有合金鉄の添加、■吹錬中に窒素ガスの吹込み、等の
方法が用いられるが、コスト的観点からみれば後者の方
法が有利である。Fig. 4 shows the normal nitrogen concentration distribution of low carbon blow-top steel in a bottom-blown converter. , even considering nitrogen absorption during tapping, the nitrogen concentration in the molten steel in the ladle is 20
It is about ppm. Therefore, methods such as (1) adding nitrogen-containing ferroalloy during tapping or casting, (2) blowing nitrogen gas during blowing, etc. are used to melt high nitrogen content steel of 40 ppu or more. From a cost standpoint, the latter method is advantageous.
しかしながら、前述のごと〈従来の窒素ガスの吹込みに
よる加窒方法では、その窒素掛止りに大きなバラツキが
あった。However, as mentioned above, in the conventional nitriding method by blowing nitrogen gas, there was a large variation in the nitrogen retention.
そこで発明者らは、吹釧中の溶鋼中酸素濃度と窒素掛止
りとの関係を詳細に調べ、第１図の結果を得た。すなわ
ち、溶鋼中酸素濃度の低下にともない窒素掛止りは増加
するが、酸素濃度が５０ｐｐｍ以下では、窒素掛止りの
バラツキが大きくなる。Therefore, the inventors investigated in detail the relationship between the oxygen concentration in the molten steel during blowing and the nitrogen retention, and obtained the results shown in FIG. 1. That is, as the oxygen concentration in molten steel decreases, the nitrogen retention increases, but when the oxygen concentration is 50 ppm or less, the variation in nitrogen retention increases.
したがって、溶鋼中窒素濃度の制御を精度よく行うには
、溶鋼中酸素濃度が５０ｐｐ１以上にあるときに窒素ガ
ス吹き込みを行う必要がある。Therefore, in order to accurately control the nitrogen concentration in molten steel, it is necessary to blow nitrogen gas when the oxygen concentration in molten steel is 50 pp1 or more.
一方、３００ρＰ■以上の酸素濃度では、バラツキは小
さいものの窒素掛止りが３．０％以下と低いため、相対
的に多量の窒素ガスを吹き込む必要があり、それに伴い
溶鋼の温度降下等や加窒用窒素ガスコストが著しく大き
くなるため経済的ではない。On the other hand, at an oxygen concentration of 300ρP■ or more, although the variation is small, the nitrogen retention is as low as 3.0% or less, so it is necessary to blow a relatively large amount of nitrogen gas, which reduces the temperature drop of the molten steel, etc. This is not economical because the cost of nitrogen gas increases significantly.
すなわち、窒素ガスを吹込む場合の？８１１中酸素濃度
としては、５０〜３００ｐｐ−の範囲が適当であること
がわかった。第２図に、吹止め窒素濃度目標５５ｐｐｍ
とし、溶鋼中炭素濃度に応じて、窒素ガス吹き込みを行
った溶鋼の取鍋における窒素濃度の分布を、特公昭５Ｂ
−３５２４４号に開示された従来法の結果とあわせて示
した。いずれも平均窒素濃度は５５ＰＰＭ程炭と十分加
窒されているが、従来法に比較して本発明法では、その
バラツキが非常に小さいことがわかる。In other words, when blowing nitrogen gas? It was found that the appropriate oxygen concentration in 811 was in the range of 50 to 300 pp-. Figure 2 shows the blow-off nitrogen concentration target of 55 ppm.
According to the carbon concentration in the molten steel, the distribution of nitrogen concentration in the ladle of molten steel to which nitrogen gas was blown was determined according to the
The results are shown together with the results of the conventional method disclosed in No.-35244. In all cases, the average nitrogen concentration was about 55 PPM, which was sufficient to nitrate the coal, but it can be seen that the variation in this was much smaller in the method of the present invention than in the conventional method.
以上のように、溶鋼中酸素濃度が５０〜３００ｐｐｍの
範囲にあるとき、その酸素濃度と目標吹止め窒素濃度と
に応じた量の窒素ガスを吹込むことによって、溶鋼中窒
素濃度の〃目■が安定的に行えるようになった。As described above, when the oxygen concentration in molten steel is in the range of 50 to 300 ppm, by injecting nitrogen gas in an amount corresponding to the oxygen concentration and the target blow-stop nitrogen concentration, the nitrogen concentration in molten steel can be adjusted to can now be performed stably.
〈実施例〉
２３０を純酸素底吹き転炉において、吹上成分目標をＣ
ｉＯ，０４％、Ｎ；４０〜８０ｐｐｍとし、酸素吹錬を
開始した。予定吹錬酸素量の１１００ＯＮ前の時点で、
温度測定及び酸素濃度測定用プローブが装着しであるセ
ンサーランスを用いて１ＢＫｔＪ中酸素４度を測定した
ところ、１１４Ｐρｍであった。そこで、この酸素濃度
と目標窒素濃度とに応じて１３ＯＮ＋ｄの窒素ガスを底
吹きした後、再び、底吹きガスを酸素に切換え、予定量
の酸素を吹込んだ後吹！しめた。吹止め炭素濃度：
０．０４２％、窒素濃度８５８ＰＰＭである高窒素含有
鋼を得ることができた。<Example> 230 was used in a pure oxygen bottom-blown converter, and the target blow-up component was set to C.
iO, 4%, N: 40 to 80 ppm, and oxygen blowing was started. At the point before the scheduled blowing oxygen amount of 1100ON,
Using a sensor lance equipped with a probe for measuring temperature and oxygen concentration, oxygen was measured at 4 degrees Celsius in 1 BKtJ and found to be 114 Pρm. Therefore, after bottom-blowing 13ON+d nitrogen gas according to this oxygen concentration and the target nitrogen concentration, the bottom-blowing gas was switched to oxygen again, and after blowing in the planned amount of oxygen! Closed. Stop carbon concentration:
A high nitrogen content steel having a nitrogen concentration of 0.042% and a nitrogen concentration of 858 PPM could be obtained.
〈発明の効果〉
本発明によれば、底吹き羽口を有する転炉において、高
窒素含有鋼を窒素濃度のバラツキを少く、迅速にかつ経
済的に溶製することができる。<Effects of the Invention> According to the present invention, high nitrogen-containing steel can be melted quickly and economically with little variation in nitrogen concentration in a converter having a bottom-blowing tuyere.
第１図は、溶鋼中酸素濃度と窒素歩止りとの関係を示す
特性図、第２図は、本発明法と従来法とによる加窒後の
取鍋内溶詞の窒素濃度分布を示す特性図、第３図は、溶
鋼中炭素濃度と窒素歩止りとの関係を示す特性図、第４
図は、吹止鋼の窒素濃度分布を示す特性図である。
特許出願人 川崎製鉄株式会社
第 １ 図
溶鋼中酸素濃度（ｐｐｍ）
第 ２ 図
窒素濃度（ｐＩ）ｍ）
第 ３ 図
第４図
窒素濃度（ｐｐｍ）Figure 1 is a characteristic diagram showing the relationship between oxygen concentration in molten steel and nitrogen yield, and Figure 2 is a characteristic diagram showing the nitrogen concentration distribution in the ladle after nitriding by the method of the present invention and the conventional method. Figure 3 is a characteristic diagram showing the relationship between carbon concentration in molten steel and nitrogen yield.
The figure is a characteristic diagram showing the nitrogen concentration distribution of blow-fitting steel. Patent applicant Kawasaki Steel Corporation Figure 1 Oxygen concentration in molten steel (ppm) Figure 2 Nitrogen concentration (pI) m) Figure 3 Figure 4 Nitrogen concentration (ppm)
Claims (1)
む混合ガスを底吹き羽口より吹き込むことによって、溶
鋼中の窒素濃度を制御する方法において、溶鋼中酸素濃
度が５０〜３００ｐｐｍの範囲で、その酸素濃度と目標
吹止めの窒素濃度とに応じて、窒素ガスもしくは、窒素
ガスを含む混合ガスを底吹きすることにより、吹止め溶
鋼中の窒素濃度を正確に制御することを特徴とする底吹
き羽口を有する転炉での加窒方法。A method of controlling the nitrogen concentration in molten steel by blowing nitrogen gas or a mixed gas containing nitrogen from the bottom blowing tuyere in a converter having a bottom blowing tuyere, in which the oxygen concentration in the molten steel is in the range of 50 to 300 ppm. The nitrogen concentration in the blowstop molten steel is accurately controlled by bottom-blowing nitrogen gas or a mixed gas containing nitrogen gas according to the oxygen concentration and the target nitrogen concentration in the blowstop. A method of nitriding in a converter with bottom blowing tuyeres.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28870486A JPH0668123B2 (en) | 1986-12-05 | 1986-12-05 | Nitrogenizing method in a converter with a bottom blowing tuyere |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28870486A JPH0668123B2 (en) | 1986-12-05 | 1986-12-05 | Nitrogenizing method in a converter with a bottom blowing tuyere |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63143214A true JPS63143214A (en) | 1988-06-15 |
| JPH0668123B2 JPH0668123B2 (en) | 1994-08-31 |
Family
ID=17733607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28870486A Expired - Fee Related JPH0668123B2 (en) | 1986-12-05 | 1986-12-05 | Nitrogenizing method in a converter with a bottom blowing tuyere |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0668123B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115595397A (en) * | 2022-10-14 | 2023-01-13 | 山东钢铁股份有限公司（Cn） | Accurate nitrogen control method for nitrogen-containing high-strength steel |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101705054B1 (en) * | 2015-10-29 | 2017-02-09 | 주식회사 포스코 | The operation method |
-
1986
- 1986-12-05 JP JP28870486A patent/JPH0668123B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115595397A (en) * | 2022-10-14 | 2023-01-13 | 山东钢铁股份有限公司（Cn） | Accurate nitrogen control method for nitrogen-containing high-strength steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0668123B2 (en) | 1994-08-31 |
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