JPS58133310A - Refining of high phosphorus steel - Google Patents

Abstract

PURPOSE:To refine high phosphorus steel stably, by a process wherein finely divided lime is added during the first half period of converter blowing so as to lower a calculated basicity and a P-residual amount is adjusted by blowing corresponding to the above stated basicity and carbon concn. in molten steel at a time of blowing-out. CONSTITUTION:In refining high phosphorus steel, an oxygen top and bottom blowing converter or an oxygen bottom blowing converter is used. In this case, finely divided lime is injected during the first half period of blowing from the tuyere of a furnace bottom or a top blowing lance so as to adjust calculated basicity (CaO wt./ SiO2 wt.) determined from oxide formed from a thrown auxiliary stock material and molten iron components to a range of <=2.5 and >=1.5. By this method, slag is rapidly formed and slopping is suppressed in an intitial stage. The addition of lime is not performed during the latter half period of blowing. In the next step, the residual amount of phosphorus in molten steel is adjusted to predetermined value by blowing corresponding to the setting of the above stated calculated basicity and oxygen concn. in molten steel at a time of blowing-out.

Description

【発明の詳細な説明】 本発明は快速鋼などの高リン鋼を転炉で溶製する方法に
関し、さらに詳しくは、酸素上底吹き併用転炉または酸
素底吹き転炉を使用し、Ｆｅ−Ｐ等の合金鉄を添加せず
に溶銑中の９７を吹錬終了時点まで残留させて高リン鋼
（Ｐ：０．１−〜Ｏ，０Ｓ−）を溶製する方法に関する
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for melting high-phosphorus steel such as high-speed steel in a converter, and more specifically, using a converter with oxygen top and bottom blowing or an oxygen bottom blowing converter to melt Fe- This invention relates to a method for melting high phosphorus steel (P: 0.1- to O, 0S-) by allowing 97 in hot metal to remain until the end of blowing without adding ferroalloys such as P.

転炉吹錬において溶銑中のリンを残留させ高リン鋼を溶
製するためには、次の２点が重要である。In order to make high phosphorus steel by leaving phosphorus in the hot metal during converter blowing, the following two points are important.

（１）　　高塩基度スラグを吹錬中に形成しないこと。(1) High basicity slag should not be formed during blowing.

このため計算塩基度を低くするようにし、石灰石の添加
量を少くする。計算塩基ｆＢｃａｌとは、転炉に投入さ
れる副原料および溶銑成分が酸化されて生成される酸化
物の重量から求まる塩基度であって、 （供給された（　ＣａＯ）分重量） である、　　′ （２）　　スラグ中酸化鉄濃度を上昇させないこと。For this reason, the calculated basicity should be lowered and the amount of limestone added should be reduced. Calculated basicity fBcal is the basicity determined from the weight of oxide produced by oxidizing the auxiliary raw materials and hot metal components input into the converter, and is (supplied (CaO) weight), (2) Do not increase the iron oxide concentration in the slag.

炉内鋼浴の攪拌を強化し、炉内における酸化反応が非平
衡な状態で進行しないようにする。Strengthen the stirring of the steel bath in the furnace to prevent the oxidation reaction in the furnace from proceeding in a non-equilibrium state.

従来の酸素上吹き転炉（以下ＬＤという）において高リ
ン鋼を溶製する場金には、吹錬時における計算塩基ＩＢ
ｃａｌを１０−４０と逐るように石灰を添加していえ、
これはＬＤにおいて計算塩基ｆＢｃａｌを２．０未満に
し九場合、吹錬初期の脱ケイ素反応が終了し脱炭最盛期
になる時点において、急激なスロッピングが発生し、炉
内スラグおよび溶鉄が突沸反応により炉外へ噴出し、操
業が困難となるためであり、逆に計算塩基度が３．０を
越えると、第１図に示すように脱リン反応が進行しゃす
く寿シ、吹錬終了時に、目標とするところの多量のリン
を溶鋼中に残留させることができないためである。第１
図は、溶鋼中炭素濃度０１ｓで吹止めた場合における計
算塩基度Ｂｃａｌと溶鋼中リン濃度〔Ｐ〕（単位はｘｉ
ｏ−ｉｎ）との関係を示すグラフであって、破線はＬＤ
、実線は酸素上底吹き併用転炉■または酸素底吹き転炉
０の場合を示す。The calculation base IB during blowing is used to melt high phosphorus steel in a conventional oxygen top-blown converter (hereinafter referred to as LD).
Lime can be added to reduce the cal to 10-40,
This is because when the calculated base fBcal is less than 2.0 in the LD, rapid slopping occurs when the desilicification reaction in the early stage of blowing ends and the decarburization reaches its peak, causing the slag and molten iron in the furnace to bump. This is because the reaction ejects out of the furnace, making operation difficult.On the other hand, if the calculated basicity exceeds 3.0, the dephosphorization reaction will proceed as shown in Figure 1, and the blowing will end. This is because sometimes the targeted amount of phosphorus cannot be left in the molten steel. 1st
The figure shows the calculated basicity Bcal and the phosphorus concentration in molten steel [P] (unit: xi
o-in), the broken line is a graph showing the relationship between LD
, the solid line indicates the case of oxygen top and bottom blowing converter (■) or oxygen bottom blowing converter (0).

また第２図は、計算塩基度Ｂ　ｃａｌとスラグ中酸化鉄
濃度（Ｔ、Ｆｅ）（単位は−）との関係を例示するグラ
フである。破線はＬＤ、実線は上記■または■炉の場合
を示す、従来のＬＤＫおける計算塩基度２．０〜３．０
の範囲における操業ではスラグ中酸化鉄濃度［Ｔ、Ｆｅ
］が上昇してしまう九め脱リンが進行する。従って従来
のＬＤでは溶銑中すｙをＯ，ＯＳ〜Ｏ，ＯＳ−程度しか
残留させることができず、高リン鋼を溶製するには、出
鋼時にＦｅ−Ｐ合金鉄を添加しまければならないという
閾題があった。Further, FIG. 2 is a graph illustrating the relationship between the calculated basicity B cal and the iron oxide concentration (T, Fe) (unit: -) in the slag. The broken line shows the LD, and the solid line shows the case of the above ■ or ■ furnace, calculated basicity of 2.0 to 3.0 in conventional LDK.
In operation in the range of , the iron oxide concentration in the slag [T, Fe
] Dephosphorization progresses, causing an increase in phosphorus. Therefore, in the conventional LD, it is possible to leave only about O,OS~O,OS- of Soy in the hot metal, and in order to produce high phosphorus steel, it is necessary to add Fe-P alloy iron at the time of tapping. There was a threshold problem.

一方、酸素上底吹き併用転炉の、酸素底吹き転炉■にお
いては、底吹き羽口からの酸素吹込みによる鋼浴の攪拌
力がＬＤよ一強化されているので、第２図に実線で示す
ように、ＬＤの場合と異り低塩基度でもスラグ中酸化鉄
濃度（Ｔ、Ｆｅ）が上昇せず、従って溶鋼は脱ダンされ
ず鋼中にリンが残や易く、第１図に示すように計算塩基
度Ｂｃａｌが１０〜３．０の範囲で溶鋼中のリンを０．
０６〜０．０３−残留させることが可能である。On the other hand, in the oxygen bottom-blown converter ■, which is a converter with oxygen top and bottom blowing, the stirring power of the steel bath due to oxygen injection from the bottom blowing tuyere is stronger than that of the LD, so the solid line in Figure 2 shows As shown in Figure 1, unlike in the case of LD, the iron oxide concentration (T, Fe) in the slag does not increase even with low basicity, and therefore the molten steel is not removed and phosphorus tends to remain in the steel. As shown, when the calculated basicity Bcal is in the range of 10 to 3.0, the phosphorus in the molten steel is 0.0.
06-0.03 - It is possible to remain.

さらに第１図から、計算塩基度Ｂｃａｌを一層低めてＬ
５〜２．０とすれば、溶鋼中のリンを０．１−〜０．０
６＊ｔで残留させることが可能であることがわかる。Furthermore, from Figure 1, the calculated basicity Bcal is further lowered and L
If it is 5 to 2.0, the phosphorus in the molten steel is 0.1- to 0.0
It turns out that it is possible to make it remain at 6*t.

次に第３図は、計算塩基度Ｂ　ｃａｌとスロッピングイ
ンデックス５ｉｎｄとの関係を示すグラフである。スロ
ッピングインデックスＳ　ｉｎｄはスロッピングが無発
生の場合をＯとし、全チャージにスロッピングが発生し
たときを１とする指数であって、スロッピングインデッ
クス５ｉｎｄが大きい程初期スロッピングが発生しやす
いことを示す。図中破線（イ）は上吹き転炉ＬＤ、上底
吹き併用転炉■、底吹き転炉■の何れを問わず、塊状石
灰を溶鋼中に添加した場合を示し、実１ｍ（ロ）は、上
底吹き併用転炉■または底吹き転炉■において、微粉石
灰をインジェクションした場合を示すものである。第３
図から明らかなように、上底吹き併用転炉■または底吹
き転炉■においてもＬＤと同様に炉上かも塊状の石灰を
投入する石灰石添加方法では脱ケイ素反応中に滓化が速
やかに遂行しないため、急激なスロッピングが発生し操
業が困難とまるという問題が生ずる。一方上底吹き併用
転炉を九は底吹き転炉において炉底羽口および／または
上吹きランスから微粉石灰をインジェクションした場合
には計算塩基度を低くしてもスロッピングが起）Ｋくい
。Next, FIG. 3 is a graph showing the relationship between the calculated basicity B cal and the slopping index 5ind. The slopping index S ind is an index that takes O when no slopping occurs and 1 when slopping occurs on all charges, and the larger the slopping index S ind, the more likely initial slopping occurs. shows. The broken line (a) in the figure indicates the case where lump lime is added to molten steel regardless of whether it is a top-blown converter LD, a top-bottom blowing combined converter ■, or a bottom-blowing converter ■. , shows the case where pulverized lime is injected in a top-bottom blowing converter (■) or a bottom-blowing converter (■). Third
As is clear from the figure, even in the top-bottom blowing converter ■ or the bottom-blowing converter ■, the limestone addition method in which lump lime is added to the top of the furnace, similar to LD, results in rapid slag formation during the desiliconization reaction. As a result, rapid slopping occurs, making operations difficult and halting. On the other hand, when pulverized lime is injected from the bottom tuyere and/or top blowing lance in a bottom blowing converter, slopping occurs even if the calculated basicity is low.

本発明はこのような知見に基いて完成したものであって
、高リン鋼ｌ１ｌＩＩＩ＃）ＩＩの問題点を解決し、低
塩基度において溶銑中のリンを極力残留さぜると共にス
ロッピング等を生じない安定した高リン鋼の溶製方法を
提供することを目的とするものである。The present invention was completed based on such knowledge, and it solves the problems of high phosphorus steel l1lIII#)II, and improves the residual phosphorus in hot metal as much as possible at low basicity, and prevents slopping, etc. The purpose of the present invention is to provide a stable method for melting high phosphorus steel that does not cause oxidation.

第４図は酸素上底吹き併用転炉■または酸素底吹き転炉
＠において微粉石灰のインジェクションパターンを変化
させて吹錬中の溶鋼中リン濃度の変化を調査しえ結果を
示す。Figure 4 shows the results of investigating changes in the phosphorus concentration in molten steel during blowing by changing the injection pattern of pulverized lime in an oxygen top and bottom blowing converter (■) or an oxygen bottom blowing converter (@).

第４図（１）は吹錬時間Ｔ（０〜１００１１Ｇで表示）
と溶鋼中リン濃度〔Ｐ〕（単位線×１０−ｓチ）との関
係を示し、図中−纏（ハ）、に）はそれぞれ第４図（ｂ
）、（Ｃ）　ＩｔＫ示す黴看石灰添加パターンにより微
粉石灰を添加し九場合を示す、　＊＊−は従来のＬＤの
場合を比較の丸め掲げた。伽）、（Ｃ）のパターン図は
、横軸に吹錬時間をとり縦軸に黴看石灰添加量をとっで
ある。（Ｃ）１図のパターンにより、＜ａ＞図のに）−
纏を得られ、溶銑中のリンを吹錬中に脱リンさせずに相
当量残留させることが可能である。Figure 4 (1) shows the blowing time T (displayed from 0 to 10011G)
and the phosphorus concentration in molten steel [P] (unit line x 10-s).
), (C) Nine cases are shown in which finely powdered lime is added according to the lime addition pattern shown in ItK. **- shows the case of conventional LD for comparison. In the pattern diagrams of (B) and (C), the horizontal axis represents the blowing time and the vertical axis represents the amount of lime added. (C) According to the pattern in figure 1, <a> in figure) -
It is possible to obtain a large amount of phosphorus in the hot metal without dephosphorizing it during blowing.

本発明は高シン鋼を溶製するに当に、酸素上底吹き転炉
■または底吹き転炉■を用い、計算塩基度が１．５以上
２．５以下になるように、微粉石灰を炉底羽口および／
ｌたは上吹きランスから、インジェクションによ抄、吹
錬期間の前半期間中に、溶鋼中に添加し、溶鋼中リンを
所要量残存させ、この残存量の調整は、上記計算塩基度
と吹止め時の溶鋼中炭素浸度とによって行なう仁とを特
徴とする。The present invention uses an oxygen top-bottom blowing converter (■) or a bottom-blowing converter (■) to produce high-thin steel, and pulverized lime is added so that the calculated basicity is 1.5 or more and 2.5 or less. Hearth tuyere and/
It is added to the molten steel during the first half of the drawing and blowing period by injection from a top blowing lance or a top blowing lance, and the required amount of phosphorus remains in the molten steel.The adjustment of this remaining amount is based on the basicity calculated above and the blowing process. It is characterized by the degree of penetration of carbon into the molten steel at the time of stopping.

本発明をさらに詳しく説明する。The present invention will be explained in more detail.

まず、吹錬中に使用するＣａＯ含有副原料（石灰石、ド
ロマイト等）の使用量を計算塩基度Ｂｃａｌが１．５以
上２．５以下になるようにする。計算塩基度が１．５未
満では、脱ケイ素反応が終了し脱炭最盛期になる吹錬初
期にスロッピングが発生し中すく操業が困難になると共
に、転炉耐火物が塩基性のものであるため耐火物浸食が
大となり不可である。First, the amount of CaO-containing auxiliary raw materials (limestone, dolomite, etc.) used during blowing is adjusted so that the calculated basicity Bcal is 1.5 or more and 2.5 or less. If the calculated basicity is less than 1.5, slopping will occur at the beginning of blowing, which is the peak stage of decarburization after the desiliconization reaction has finished, making operation difficult, and the converter refractories will be basic. Because of this, corrosion of the refractories would be significant, making it impossible.

また、計算塩基度Ｂｃａｌが１５を越えると第１図に示
すように脱リン反応が進行し中すく溶銑中リンを多量に
残留させることができなくなる。Furthermore, when the calculated basicity Bcal exceeds 15, the dephosphorization reaction proceeds as shown in FIG. 1, making it impossible to leave a large amount of phosphorus in the hot metal.

次に本発明では、吹錬−始と同時に、吹錬前半に投入さ
れる副原料と溶銑酸分の酸化による生成酸化物から計算
されえ微粉石灰を、微粉石灰を底吹き羽口および／また
は上吹きランスからインジェクションし、吹錬後半には
脱リンを抑えるため石灰石の添加は行なわない。微粉石
灰をインジェクションによに添加するのは、低い計算塩
基度においても吹錬初期Ｋ　（ＣａＯ）　／　（ＳｉＯ
ｘ　）が１．５以上のスラグを速やかに形成させ初期ス
ロッピングの発明を抑制するためである。吹錬前半にの
み微粉石灰を添加し吹錬末期に石灰を添加しないのは、
吹錬末期は炭素濃度も鍬下してお抄、スラグ中酸化鉄濃
度（Ｔ、Ｆｅ）が上昇しゃすぐ説リン反応が進行し申す
＜１ゐのを防止するためである。Next, in the present invention, at the same time as the blowing starts, pulverized lime is added to the bottom blowing tuyere and/or Injection is performed from the top blowing lance, and limestone is not added in the latter half of blowing to suppress dephosphorization. Adding pulverized lime by injection increases the initial K (CaO) / (SiO) of blowing even at low calculated basicity.
This is to quickly form a slag with x) of 1.5 or more and to suppress the initial slopping. Adding pulverized lime only in the first half of blowing and not adding lime at the end of blowing is
This is to prevent the phosphorus reaction from proceeding as soon as the iron oxide concentration (T, Fe) in the slag increases.

この点はすでに第４図（ｂ）、（Ｃ）のパターンで説明
した通りであり、本発明は第４図（Ｃ）パターンと第４
図（ａ）の−纏に）に示すように溶鋼中リンを残存させ
るものである。This point has already been explained with respect to the patterns in FIGS. 4(b) and (C), and the present invention is applicable to the patterns in
As shown in Figure (a), phosphorus remains in the molten steel.

次に、本発明における鋼中リン濃度を所定値に調整する
操作は、上記計算塩基度の設宇と溶鋼中の吹止炭素濃度
とによって行なう。第５図は計算塩基置割に、吹止時の
溶鋼中炭素濃度（Ｃ）　（Ｘ１０””　−）と吹止時第
鋼中リン濃度（Ｐ）（ＸＩＯ″＄−）との関係を示すも
のである。第５図に示すように、溶銑中に存在していた
リンを吹止時に鋼中に６．０７１以上残留させたい場合
には、計算塩基度”Ｃａｌ　ｔ　１．５以上２−０以下
とすると共に、吹止炭素濃度を０．１ｓ以上にする。ま
た溶銑中に存在していたリンを鋼中に０．０５−以上〜
ｏ、ｏｙ＊未満残留させたいときは、計算塩基度を２．
０以上〜２．５以下とし、吹止め炭素濃度をＯ，ＯＳ＊
以上〜０．０９−以下とすることによって調整できる。Next, the operation of adjusting the phosphorus concentration in the steel to a predetermined value in the present invention is performed by setting the calculated basicity and the blowout carbon concentration in the molten steel. Figure 5 shows the relationship between the carbon concentration in the molten steel at the time of blow-off (C) (X10''''-) and the phosphorus concentration in the molten steel at the time of blow-off (P) (XIO''$-) in the calculated base position. As shown in Fig. 5, if you want the phosphorus present in the hot metal to remain in the steel at the time of blow-stopping, the calculated basicity "Cal t" should be 1.5 or more 2- 0 or less, and the blow-off carbon concentration to be 0.1 s or more. In addition, the phosphorus present in the hot metal is added to the steel by 0.05 or more.
If you want to have less than o, oy* remaining, set the calculated basicity to 2.
0 or more and 2.5 or less, and the blow-stop carbon concentration is O, OS*
It can be adjusted by setting it between 0.09 and 0.09.

本発明方法では、鉄鉱石、ミルスケール等の酸化鉄の投
入は吹錬末期（吹錬時間の７０〜１０Ｇ−の期間）には
行なわない、その理由は吹錬末期に上記の酸化鉄を大量
に投入するとスラグ中酸化鉄濃度（Ｔ、Ｆｅ）が上昇し
脱リンが進行して、所期の鋼中リンを確保することがで
きなくなるからである。In the method of the present invention, iron oxides such as iron ore and mill scale are not introduced at the final stage of blowing (period of 70 to 10 G- of the blowing time). This is because if the iron oxide concentration (T, Fe) in the slag increases and dephosphorization progresses, it becomes impossible to secure the desired amount of phosphorus in the steel.

次に本発明方法の実施例を説明する。Next, examples of the method of the present invention will be described.

実施例１ ２５Ｇ）ン蒙素上底吹會併用転炉に次の組成の溶銑２５
０トンを装入しえ。Example 1 25G) Molten iron with the following composition was put into a converter combined with top and bottom blowing.
Charge 0 tons.

ｃ／ｌｓ＊　　５ｉ１０．３５１Ｇ　　Ｍｍｌｏ、５−
Ｐ／＠、１４チ　Ｓ１０．ｏ　を畳　温度／　１，３０
０℃吹錬開始と同時に、計算塩基度が２．．０となるよ
うに１黴看石灰１３Ｌ５ｋＩＩ／ｌを底吹−羽口よ抄酸
素ガスでインジェクションしえ、吹き込み速度社０．３
　ｋｌｌ／　ｔ　ｍｉｘ　〜５　ｋｆ／　ｔ　ｍｉｘの
範囲で調整し、吹錬初期のみインジェクションを行なっ
た。酸化鉄（鉄鉱石およびミルスケール）４５に９／ｌ
を吹錬酸素量が５ＮｆＩ／／ｌ〜３０　Ｎｇｌ／　ｔの
間に投入した。特に３　ＯＮｄ／を以後は投入しないと
とに留意し九。上吹き吹錬は底吹き吹錬終了の１分以上
前に終了し、サブランスを吹錬終了予安酸素量の６Ｎｄ
／を前に投入し、吹止炭素濃度が０．１−となるように
操作した。c/ls* 5i10.351G Mmlo, 5-
P/@, 14chi S10. o Tatami temperature / 1,30
At the same time as the start of 0°C blowing, the calculated basicity was 2. ．． Inject 13L of lime 5kII/l through the bottom blow and tuyere with oxygen gas so that the injection rate is 0.3.
It was adjusted in the range of kll/t mix to 5 kf/t mix, and injection was performed only at the initial stage of blowing. Iron oxide (iron ore and mill scale) 45 to 9/l
The blowing oxygen amount was between 5 NfI//l and 30 Ngl/t. Pay special attention to the fact that 3 ONd/ should not be used after that. The top blowing should be completed at least 1 minute before the end of the bottom blowing, and the sublance should be filled with 6 Nd of oxygen to prepare for the end of the blowing.
/ was added beforehand, and the operation was performed so that the blown carbon concentration was 0.1-.

吹止時の成分ｉしては以下のような組成を得て出鋼した
。The following composition was obtained as component i at the time of blow-stopping, and the steel was tapped.

Ｃ１０，１１１Ｍｕ／６．２１１　　Ｐｌｏ、０７５チ
Ｓ１０．０１１　　Ｉ！度７１６６０℃命令リン濃度が
Ｐｌｏ、０７５＄＆ので出鋼時にＦｅ−Ｐ合金鉄の添加
を行なう必要はない。C10,111Mu/6.211 Plo,075chiS10.011 I! Since the phosphorus concentration at 71,660° C. is Plo, 075 $&, it is not necessary to add Fe--P alloy iron at the time of tapping.

実施例２ ２５０トン酸素上底吹き併用転炉において本発明法によ
り高リン鋼を溶製し九場合と、−・上吹き転炉において
従来法によ妙法製し九場合の吹錬実績を比較した結果第
１表の通りである。′第１表　高９ｙ鋼溶製與績比較（
２５０）ン転炉）本発明法により次の効果が得られる。Example 2 Comparison of the blowing results of 9 cases in which high phosphorus steel was melted by the method of the present invention in a 250 ton oxygen top-bottom blowing converter and 9 cases in which high phosphorus steel was made by the conventional method in a top-blown converter. The results are shown in Table 1. 'Table 1 Comparison of high 9y steel melting performance (
250) Converter) The following effects can be obtained by the method of the present invention.

（１）快削性を要求される０、０５〜０．１−のリンを
含有する高リン鋼を脱リン抑制によって、安定し九操業
条件の下に溶製することができる。(1) By suppressing dephosphorization, high phosphorus steel containing 0.05 to 0.1 - phosphorus, which requires free machinability, can be produced stably under nine operating conditions.

（２）　　低塩基度操業のため、石灰石原単位が低減す
る。(2) Low basicity operation reduces limestone consumption.

（３）脱リン抑制により溶銑中リンを残留させるので、
Ｆｅ−Ｐ合金鉄原単位が低減する。(3) Since phosphorus remains in the hot metal by suppressing dephosphorization,
Fe-P alloy iron consumption rate is reduced.

（４）　　微粉石灰のインジェクションによる吹錬初期
スロッピングの抑制と、スラグボリューム低減によるス
ラグへの鉄ロス低減により製出鋼歩止が向上する。(4) The yield rate of steel production is improved by suppressing slopping in the initial stage of blowing by injecting pulverized lime and reducing iron loss to slag by reducing slag volume.

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

第１１ｎｔｉ計算塩基度”ｃａｌ　と溶鋼中リン濃度（
Ｐ）（ＸＩＯ−’１Ｇ）との関係例（吹止炭素濃度０．
１−の場合）を示すグラフ、第２図は計算塩基度Ｂｃａ
ｌとスラグ中酸化鉄濃度（Ｔ、Ｆｅ　　）（−）との関
係を示すグラフである。第１図、第２図において破線は
従来の酸素上吹き転炉（ＬＤ）、実線は酸素上底吹き転
炉のまたは酸素底吹き転炉■の場合を示す。第３図は計
算塩基度Ｂｃａｌとスロツビングイ／デツクスＳ　　と
の関係を示すグラ盃ｎｄ フで５ｉｎｄはスロッピング無発生を０１全チヤ一ジス
ロツピング発生を１としである。第３図中破線（イ）は
塊状石灰を溶鋼中に添加した場合、実線←）は酸素上底
吹き併用転炉■または酸素底吹き転炉＠において微粉石
灰をインジェクションした場合を示す。第４図（１）は
酸素上底吹き併用転炉■または酸素底吹き転炉■におい
て微粉石灰のインジエタションパターンを変化させたと
きの吹錬中の溶鋼中リン濃度（Ｐ）（ｘｌＯ−”ＩＧ）
の変化を示し、一点鎖線（ハ）は第４図（ｂ）のパター
ン、実線に）は第４図（Ｃ）のパターンで微粉石灰を添
加した本発明方法の場合を示す。第５図は、計算塩基覆
胴に、吹止時の溶鋼中炭素濃度（Ｃ）（ｘｔＯ−”＋Ｇ
）と吹止時溶鋼中リン濃度ＣＰ）（ｘｌｏ−１％）との
関係を示すグラフである。第５図中実線は計算塩基度１
．５〜２．０１破線は計算塩基度４０〜２．５の場合を
示す。 Ｂｃａｌ・・・計算塩基度、〔Ｐ〕・・・溶鋼中リン濃
度（ｘ　ｌｏ−”　１）、ＬＤ−・・酸素上吹き転炉、
−■−・・酸素上底吹き併用転炉、■・−・酸素底吹き
転炉、（Ｔ　、　Ｆｅ　　）−ｘラグ中酸化鉄１１１（
ＩＧ）、５ｉｎｄ・・・スロッピングインデックス、（
イ）・・・境石灰石添加の場合、（ロ）・−微粉石灰イ
ンジェクションの場合、（ハ）・−微粉石灰添加（ｂ）
　パターンの場合、に）・・−黴看石灰添加（Ｃ）パタ
ーンの場合（本発明）、（ホ）・・・従来方法の場合、
〔Ｃ〕・・・吹止時の溶鋼中炭素濃度（ｘ　１ｏ−”　
−）第１図 １２３４５ →Ｂｃａｌ 第２図 →Ｂｃａｌ 第３図 １　２　３ ｃａｌ 第４図 −〉吹錬時間（％）11th nti calculated basicity "cal" and phosphorus concentration in molten steel (
Example of relationship with P) (XIO-'1G) (blowing carbon concentration 0.
Figure 2 shows the calculated basicity Bca
1 is a graph showing the relationship between l and iron oxide concentration in slag (T, Fe) (-). In FIGS. 1 and 2, the broken line indicates a conventional oxygen top-blown converter (LD), and the solid line indicates an oxygen top-blown converter or an oxygen bottom-blown converter (2). FIG. 3 is a graph showing the relationship between the calculated basicity Bcal and the throbbing index S, where 5ind is 01 for no slopping to occur, and 1 is for all slopping to occur. The broken line (A) in FIG. 3 shows the case where lump lime is added to the molten steel, and the solid line ←) shows the case where pulverized lime is injected in the oxygen top and bottom blowing converter ■ or the oxygen bottom blowing converter @. Figure 4 (1) shows the phosphorus concentration (P) in molten steel during blowing (xlO- ”IG)
The dashed line (C) shows the pattern of FIG. 4(b), and the solid line (c) shows the pattern of FIG. 4(C) in the case of the method of the present invention in which pulverized lime was added. Figure 5 shows the carbon concentration in molten steel (C) (xtO-”+G
) and the phosphorus concentration in molten steel at the time of blow-off CP) (xlo-1%). The solid line in Figure 5 shows the calculated basicity of 1.
．． 5-2.01 The broken line shows the case where the calculated basicity is 40-2.5. Bcal... Calculated basicity, [P]... Phosphorus concentration in molten steel (x lo-" 1), LD-... Oxygen top-blown converter,
−■−・Oxygen top and bottom blowing converter, ■・−・Oxygen bottom blowing converter, (T, Fe)−x iron oxide in lag 111 (
IG), 5ind... slopping index, (
B)... In the case of boundary limestone addition, (B) - In the case of fine powder lime injection, (C) - Fine powder lime addition (b)
In the case of a pattern, (2)...-In the case of a lime addition (C) pattern (the present invention), (E)...In the case of a conventional method,
[C]...Carbon concentration in molten steel at the time of blow-off (x 1o-"
-) Fig. 1 12345 → Bcal Fig. 2 → Bcal Fig. 3 1 2 3 cal Fig. 4 -〉Blowing time (%)

Claims (1)

【特許請求の範囲】[Claims] １　高りン鋼を溶製するに当ヤ、□酸素上底吹き併用転
炉また轄酸素底吹き転炉を使用し、投入副原料および溶
銑成分から生成される酸化物から求まる計算塩基度が１
．５以上２．５以下Ｋｔ＆ように、吹錬の前半期間中に
、炉底羽口および／まえは上吹きランスから微粉石灰を
インジェクションによ艶消鋼中に添加し、前記計算塩基
度と吹止め時の溶鋼中炭素濃度とにより溶鋼中リン残留
量を所定値に調整吹錬することを特徴とする、高リン鋼
の溶製方法。1 In order to melt Takarin steel, we use an oxygen top and bottom blowing converter or an oxygen controlled bottom blowing converter, and calculate the basicity calculated from the oxides produced from the input auxiliary raw materials and hot metal components. 1
．． During the first half of the blowing period, pulverized lime is added to the matte steel by injection from the bottom tuyere and/or the top blowing lance so that the calculated basicity A method for producing high phosphorus steel, which is characterized by blowing to adjust the residual amount of phosphorus in the molten steel to a predetermined value depending on the carbon concentration in the molten steel at the time of stopping.