JPH0512410B2 - - Google Patents
Info
- Publication number
- JPH0512410B2 JPH0512410B2 JP15345488A JP15345488A JPH0512410B2 JP H0512410 B2 JPH0512410 B2 JP H0512410B2 JP 15345488 A JP15345488 A JP 15345488A JP 15345488 A JP15345488 A JP 15345488A JP H0512410 B2 JPH0512410 B2 JP H0512410B2
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- gas
- steel
- oxygen
- carbon
- 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 - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 98
- 239000010959 steel Substances 0.000 claims description 98
- 239000007789 gas Substances 0.000 claims description 38
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 29
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 29
- 229910052760 oxygen Inorganic materials 0.000 claims description 29
- 239000001301 oxygen Substances 0.000 claims description 29
- 229910052799 carbon Inorganic materials 0.000 claims description 28
- 239000002893 slag Substances 0.000 claims description 27
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 15
- 230000001590 oxidative effect Effects 0.000 claims description 13
- 238000007664 blowing Methods 0.000 claims description 12
- 230000003647 oxidation Effects 0.000 claims description 7
- 238000007254 oxidation reaction Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 3
- 238000005261 decarburization Methods 0.000 description 20
- 238000000034 method Methods 0.000 description 20
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 16
- 238000007654 immersion Methods 0.000 description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 11
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 11
- 229910052748 manganese Inorganic materials 0.000 description 11
- 239000011572 manganese Substances 0.000 description 11
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 8
- 229910052786 argon Inorganic materials 0.000 description 8
- 229910002091 carbon monoxide Inorganic materials 0.000 description 8
- 229910001882 dioxygen Inorganic materials 0.000 description 8
- 238000009849 vacuum degassing Methods 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は極低炭素鋼の溶製方法に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing ultra-low carbon steel.
（従来の技術）
従来、極低炭素鋼を溶製するためには、転炉等
で精錬した溶鋼を未脱酸状態で取鍋に受鋼し、
RH真空脱ガス装置等で溶鋼を真空下に配置し、
溶鋼中の炭素と酸素とを反応させる方法で脱炭処
理した後、最終目標の溶鋼成分になるように、合
金を添加する溶製方法が広く行われている。(Prior art) Conventionally, in order to melt ultra-low carbon steel, molten steel refined in a converter etc. is received in a ladle in an undeoxidized state, and
Place the molten steel under vacuum using an RH vacuum degassing device, etc.
A widely used melting method involves decarburizing molten steel by reacting carbon and oxygen, and then adding an alloy to achieve the final target molten steel composition.
その際、脱炭速度をより短縮するため、真空脱
ガス装置において酸素、あるいは二酸化炭素等の
ガスまたは酸化鉄等の粉末を添加する方法（たと
えば特開昭49−34414、特開昭51−151211、特開
昭51−151212）、反応界面積を増大するため大量
のガスを吹き込む方法（特開昭52−5641）等が開
発されている。 At that time, in order to further shorten the decarburization rate, there is a method of adding gas such as oxygen or carbon dioxide or powder such as iron oxide in a vacuum degassing device (for example, JP-A-49-34414, JP-A-51-151211). , JP-A-51-151212), and a method of blowing a large amount of gas to increase the reaction interface area (JP-A-52-5641).
（発明が解決しようとする課題）
一般に、溶鋼を脱炭する際、(1)式で示すように
溶鋼中の炭素と溶鋼中の酸素との反応によりCO
ガスを生成させ、COガスを気相側に除去する方
法が採用されている。(Problem to be Solved by the Invention) Generally, when decarburizing molten steel, as shown in equation (1), carbon in the molten steel reacts with oxygen in the molten steel, causing CO
A method has been adopted in which gas is generated and CO gas is removed from the gas phase.
Ｃ＋Ｏ→CO……(1)
脱炭を容易にするためには、溶鋼中に酸素が必
要であり、溶鋼中の酸素を増加させる方法とし
て、一般に純酸素上吹転炉方式が採用されてい
る。 C+O→CO……(1) Oxygen is necessary in molten steel to facilitate decarburization, and a pure oxygen top-blowing converter method is generally used as a method to increase oxygen in molten steel. .
しかし、この方法では溶鋼中の炭素含有量が
0.02％以下になると脱炭が進行しなくなり、目的
の極低炭素鋼が溶製できないばかりか、寧ろ、鉄
の酸化が生じ、溶鋼歩留の低下、および有効な成
分であるマンガン含有量の低下を招く等の問題が
あつた。 However, this method reduces the carbon content in molten steel.
If it is less than 0.02%, decarburization will not proceed and the desired ultra-low carbon steel will not be produced, but the iron will oxidize, resulting in a decrease in the yield of molten steel and a decrease in the manganese content, which is an effective component. There were problems such as inviting
そこで、鉄の酸化よりも、溶鋼中の炭素の酸化
を優先させるため、気体酸素あるいは固体酸素を
溶鋼中に供給し、溶鋼中の酸素を増加させると同
時に、処理溶鋼を真空下に置き、気体側の一酸化
炭素の分圧を低下させることにより、(1)式の反応
を右側に進行させる方法が採用されている。 Therefore, in order to give priority to the oxidation of carbon in the molten steel over the oxidation of iron, gaseous oxygen or solid oxygen is supplied into the molten steel to increase the oxygen in the molten steel, and at the same time, the treated molten steel is placed under a vacuum to A method has been adopted in which the reaction of equation (1) proceeds to the right by lowering the partial pressure of carbon monoxide on the side.
つまり、(2)式でPcoを小さくすれば、同じ
〔Ｏ〕であつても〔Ｃ〕を小さくすることが可能
となる。 In other words, by reducing Pco in equation (2), it is possible to reduce [C] even for the same [O].
〔Ｃ〕＝Pco／Ｋ〔Ｏ〕……(2)
Pco：ガス側の一酸化炭素ガスの分圧
〔Ｃ〕：溶鋼中の炭素濃度
〔Ｏ〕：溶鋼中の酸素濃度
Ｋ ：平衡定数
上記方法によれば、溶鋼中の炭素含有量は0.02
％以下に低下させることが可能であり、且つ、鉄
の酸化も抑制できる等の観点で有利であるため、
工業的にはRH真空脱ガス装置等による極低炭素
鋼の溶鋼方法が広く採用されている。 [C] = Pco/K[O]...(2) Pco: Partial pressure of carbon monoxide gas on the gas side [C]: Carbon concentration in molten steel [O]: Oxygen concentration in molten steel K: Equilibrium constant Above According to the method, the carbon content in molten steel is 0.02
% or less, and is advantageous in that it can also suppress the oxidation of iron.
Industrially, methods for producing ultra-low carbon steel using RH vacuum degassing equipment are widely used.
しかし、この方法は、高価な真空脱ガス装置が
必要なばかりでなく、耐火物等の溶損のため、処
理費用が高くなる等の問題があつた。 However, this method not only requires an expensive vacuum degassing device, but also has problems such as increased processing costs due to melting and loss of refractories and the like.
本発明は、上記のような問題点を解決し、安価
な設備で、従来行われている高価な真空脱ガス装
置で溶製すると同等の極低炭素鋼の溶製方法を提
供するために開発されたものである。 The present invention was developed in order to solve the above-mentioned problems and provide a method for producing ultra-low carbon steel using inexpensive equipment that is equivalent to producing it using the conventionally expensive vacuum degassing equipment. It is what was done.
（課題を解決するための手段）
本発明は取鍋内容鋼表面上に存在する酸化性ス
ラグの占める面積を、溶鋼表面積の20％以下に減
少せしめた、炭素含有量0.04〜0.02％の溶鋼表面
に、酸素分圧0.5〜0.01気圧に調整した酸化性ガ
スと不活性ガスとの混合ガスを吹きつけ、溶鋼の
酸化を抑制しつつ溶鋼を脱炭し、炭素含有量0.02
％以下の溶鋼を溶製する極低炭素鋼の溶製方法で
ある。(Means for Solving the Problems) The present invention provides a surface area of molten steel with a carbon content of 0.04 to 0.02%, which reduces the area occupied by oxidizing slag on the surface of the steel in the ladle to 20% or less of the surface area of the molten steel. A mixed gas of oxidizing gas and inert gas adjusted to an oxygen partial pressure of 0.5 to 0.01 atm is blown onto the molten steel to decarburize the molten steel while suppressing its oxidation, resulting in a carbon content of 0.02
This is a method for producing ultra-low carbon steel that produces molten steel of less than 30%.
（作用）
本発明者らは、種々の実験を重ねてきた結果、
極低炭素鋼を溶製する場合、必ずしも溶鋼表面を
高価な真空脱ガス設備を用いて、高真空下に保つ
必要はなく、溶鋼中の炭素と溶鋼中の酸素が反応
する気相側界面の一酸化炭素ガスの分圧を低下さ
せれば良いことを見出した。(Function) As a result of various experiments, the present inventors found that
When producing ultra-low carbon steel, it is not necessary to keep the surface of the molten steel under high vacuum using expensive vacuum degassing equipment. It was discovered that it is sufficient to reduce the partial pressure of carbon monoxide gas.
つまり、溶鋼中の炭素と溶鋼中の酸素が反応す
る界面の気相側の一酸化炭素ガス濃度を他のガス
で希釈すれば極低炭素鋼の溶製が可能であること
を見出した。 In other words, we have found that it is possible to produce ultra-low carbon steel by diluting the carbon monoxide gas concentration on the gas phase side of the interface where carbon in molten steel and oxygen in molten steel react with another gas.
然らば、純酸素上吹転炉法による脱炭反応の場
合、多量の純酸素ガスを溶鋼表面に供給している
ので、気相側の一酸化炭素ガスの分圧は低いと考
えられるのに、何故、溶鋼中の炭素含有量が0.02
％以下になると脱炭が進行しなくなり、目的の極
低炭素鋼が溶製できないばかりか、寧ろ、鉄の酸
化が生じ、溶鋼歩留の低下、および有効な成分で
あるマンガン含有量の低下を招くかについて、再
度種々の実験を重ねてきた。 Therefore, in the case of decarburization using the pure oxygen top-blown converter method, a large amount of pure oxygen gas is supplied to the surface of the molten steel, so the partial pressure of carbon monoxide gas on the gas phase side is thought to be low. Why is the carbon content in molten steel 0.02?
% or less, decarburization will not proceed and the desired ultra-low carbon steel will not be produced.In fact, oxidation of the iron will occur, resulting in a decrease in the yield of molten steel and a decrease in the manganese content, which is an effective component. We have repeatedly conducted various experiments to see if this is possible.
その結果、純酸素上吹転炉法では一般に、脱炭
と同時に脱珪、脱燐、脱硫等のため、溶鋼表面に
精錬用スラグを置き精錬処理を行つていること、
及び純酸素ガスを溶鋼に供給していることが脱炭
停滞の原因であることが分かつた。 As a result, in the pure oxygen top-blowing converter process, refining slag is generally placed on the surface of the molten steel for decarburization and desiliconization, dephosphorization, desulfurization, etc.
It was found that supplying pure oxygen gas to molten steel was the cause of stagnation in decarburization.
つまり、このように溶鋼表面上にスラグが存在
する場合、溶鋼中の炭素と酸素が反応して、一酸
化炭素ガスの気泡を生成させるには、生成する一
酸化炭素ガスの分圧は大気圧とスラグの静圧との
和より大きくなる必要がある。従つて、転炉法で
は通常、ガス側の一酸化炭素ガスの分圧は小さい
にも関わらず、溶鋼中炭素含有量が0.02％以下に
なると脱炭が進行しなくなつていると考えられ
る。 In other words, when slag exists on the surface of molten steel, in order for carbon and oxygen in the molten steel to react and generate carbon monoxide gas bubbles, the partial pressure of the generated carbon monoxide gas must be atmospheric pressure. and the static pressure of the slag. Therefore, although the partial pressure of carbon monoxide gas on the gas side is usually small in the converter method, it is thought that decarburization stops progressing when the carbon content in molten steel becomes 0.02% or less.
又、通常、転炉で炭素含有量４％程度の溶銑か
ら精錬しており、処理時間を短くするため、純酸
素ガスを供給しているが、極低炭素鋼を溶製する
ような場合は、炭素含有量に見合つて、酸素供給
速度は小さくて良いことが分かつた。寧ろ、酸素
供給速度が大き過ぎると鉄および溶鋼中の有効成
分であるマンガンが酸化し、その酸化鉄および酸
化マンガンが上述したスラグと同様の理由によ
り、悪影響を生じさせること、および過剰酸素に
より脱炭反応サイドの減少を招くことがわかつ
た。 Also, normally, hot metal with a carbon content of about 4% is refined in a converter, and pure oxygen gas is supplied to shorten the processing time, but when producing ultra-low carbon steel, It was found that the oxygen supply rate may be low depending on the carbon content. On the contrary, if the oxygen supply rate is too high, manganese, which is an active ingredient in iron and molten steel, will oxidize, and the iron oxide and manganese oxide will cause an adverse effect for the same reason as the slag mentioned above. It was found that this resulted in a decrease in the charcoal reaction side.
以上のごとき検討結果から、取鍋内容鋼表面上
に存在する酸化性スラグの占める面積を溶鋼表面
積の20％以下に減少せしめた炭素含有量0.04〜
0.02％の溶鋼表面に、酸素分圧0.5〜0.1気圧に調
整した酸化性ガスと不活性ガスとの混合ガスを吹
きつけ、溶鋼の酸化を抑制しつつ、溶鋼を脱炭す
れば、炭素含有量0.02％以下の極低炭素鋼の溶製
が可能であることを見出した。 From the above study results, it was found that the carbon content of 0.04 to 0.04 was enough to reduce the area occupied by oxidizing slag on the surface of the steel in the ladle to less than 20% of the surface area of molten steel.
By blowing a mixed gas of oxidizing gas and inert gas adjusted to an oxygen partial pressure of 0.5 to 0.1 atm onto the surface of 0.02% molten steel to decarburize the molten steel while suppressing oxidation of the molten steel, the carbon content can be reduced. We have discovered that it is possible to produce ultra-low carbon steel with a carbon content of 0.02% or less.
本発明の要件である、取鍋内容鋼表面上に存在
する酸化性スラグの占める面積を、溶鋼表面積の
20％以下に減少せしめる理由は、20％以上の面積
比では酸化性スラグによる溶鋼への酸素供給のた
め、吹きつけガスの酸素分圧だけでは溶鋼の酸素
が抑制できなくなるためである。 The area occupied by the oxidizing slag present on the surface of the steel in the ladle, which is a requirement of the present invention, is the surface area of the molten steel.
The reason for reducing the area ratio to 20% or less is that when the area ratio is 20% or more, oxygen is supplied to the molten steel by the oxidizing slag, so oxygen in the molten steel cannot be suppressed only by the oxygen partial pressure of the blown gas.
尚、面積比とは溶鋼表面を目視観察した場合、
裸湯となつている溶鋼表面積と酸化性スラグで被
覆されている溶鋼表面積の合計溶鋼表面積に対し
て、酸化性スラグで被覆されている溶鋼表面積の
百分率である。 In addition, area ratio is when visually observing the surface of molten steel.
It is the percentage of the molten steel surface area covered with oxidizing slag to the total molten steel surface area of the molten steel surface area as bare hot water and the molten steel surface area covered with oxidizing slag.
又、酸素分圧を0.5〜0.01気圧に調整した混合
ガスを用いる理由は0.5気圧以上では鉄および溶
鋼中のマンガンを酸化させ、酸化性スラグと同様
の理由により、悪影響を生じることおよび、過剰
酸素により脱炭反応サイドの減少を招くためであ
り、0.01気圧以下では脱炭に必要な酸素が不足す
るため、本発明では酸素分圧を0.5〜0.01気圧と
した。 The reason for using a mixed gas with an oxygen partial pressure adjusted to 0.5 to 0.01 atm is that above 0.5 atm, it oxidizes the iron and manganese in the molten steel, causing an adverse effect for the same reason as oxidizing slag, and that excessive oxygen This is to cause a decrease in the decarburization reaction side, and since oxygen necessary for decarburization is insufficient below 0.01 atm, the oxygen partial pressure is set to 0.5 to 0.01 atm in the present invention.
取鍋内容鋼表面上に存在する酸化性スラグの占
める面積を溶鋼表面積の20％以下に減少せしめる
方法は溶鋼内に浸漬管を浸漬し、浸漬管内の転炉
スラグを浸漬管の外に排出するものであるが、上
記方法以外に、浸漬管内の転炉スラグを減少せし
める方法としては、出鋼時にスラグボール、スラ
グストツパー等により取鍋内へのスラグ流失を抑
えるか、あるいは出鋼した後、取鍋内からスラグ
ドラツガー等を用い取鍋の外に排出しても良い。 A method for reducing the area occupied by oxidizing slag on the surface of the steel in the ladle to less than 20% of the surface area of molten steel is to immerse a dipping tube in the molten steel and discharge the converter slag inside the dipping tube to the outside of the dipping tube. However, in addition to the methods mentioned above, methods for reducing converter slag in the immersion tube include using slag balls, slag stoppers, etc. to prevent slag from flowing into the ladle during tapping, or using a slag after tapping Alternatively, the slag may be discharged from inside the ladle using a slag dragger or the like.
（実施例） 以下実施例を第１図を用いて詳細に説明する。(Example) An embodiment will be described in detail below with reference to FIG.
実施例１に用いた処理前溶鋼１は、250t転炉で
溶鋼から炭素0.04％、マンガン0.25％に溶製した
溶鋼を取鍋２に未脱酸状態で出鋼したものであ
り、取鍋内容鋼温度は1635℃であつた。その後、
取鍋下部に配置したポーラスプラグ４からアルゴ
ンガスを25Nm3／hr吹き込みつつ、溶鋼内に浸
漬管３を浸漬し、浸漬管内の転炉スラグ５を浸漬
管の外側に排出した。これにより、浸漬管内の溶
鋼表面は、面積比で80％が裸湯となつた。 The pre-processed molten steel 1 used in Example 1 is molten steel made into 0.04% carbon and 0.25% manganese from molten steel in a 250t converter and tapped into a ladle 2 in an undeoxidized state, and the contents of the ladle are as follows: The steel temperature was 1635°C. after that,
The immersion tube 3 was immersed in the molten steel while blowing argon gas at 25 Nm 3 /hr from the porous plug 4 placed at the bottom of the ladle, and the converter slag 5 in the immersion tube was discharged to the outside of the immersion tube. As a result, 80% of the surface area of the molten steel inside the immersion tube was exposed.
つぎに、溶鋼表面から1mの位置に配置した上
吹きランス６を用い、酸素分圧を0.1気圧に調整
した酸素ガスとアルゴンの混合ガスを、流量
25000Nm3／hrで溶鋼表面に吹きつけ、脱炭処理
を20分間行つた。 Next, using a top blowing lance 6 placed 1 m from the molten steel surface, a mixed gas of oxygen gas and argon with the oxygen partial pressure adjusted to 0.1 atm was introduced at a flow rate.
Decarburization treatment was performed for 20 minutes by spraying the surface of the molten steel at 25,000 Nm 3 /hr.
なお上記以外に、酸素分圧を調整したガスとし
ては、酸化性ガスとして酸素ガス以外に二酸化炭
素ガス、空気あるいは水蒸気を用いても良い。ま
た、中性ガスとしては、アルゴンガス以外に窒素
ガスを用いても良い。尚空気に関しては単独での
使用も可能である。 In addition to the above, as the gas whose oxygen partial pressure is adjusted, carbon dioxide gas, air, or water vapor may be used as the oxidizing gas other than oxygen gas. Further, as the neutral gas, nitrogen gas may be used instead of argon gas. As for air, it is also possible to use it alone.
脱炭処理後の溶鋼の炭素含有量は0.005％、マ
ンガンは0.21％、溶鋼温度1605℃であつた。 After decarburization, the carbon content of the molten steel was 0.005%, the manganese content was 0.21%, and the molten steel temperature was 1605°C.
実施例２に用いた処理前溶鋼１は、250t転炉で
溶銑から炭素0.04％、マンガン0.25％に溶製した
溶鋼を取鍋２に未脱酸状態で出鋼したものであ
り、取鍋内溶鋼温度は1635℃であつた。その後、
取鍋下部に配置したポーラスプラグ４からアルゴ
ンガスを25Nm3／hr吹き込みつつ、溶鋼内に浸
漬管３を浸漬し、浸漬管内の転炉スラグ５を浸漬
管の外側に排出した。これにより、浸漬管内の溶
鋼表面は、面積比で80％が裸湯となつた。 The pre-processed molten steel 1 used in Example 2 is molten steel that has been melted into 0.04% carbon and 0.25% manganese from hot metal in a 250-ton converter and tapped into a ladle 2 in an undeoxidized state. The molten steel temperature was 1635°C. after that,
The immersion tube 3 was immersed in the molten steel while blowing argon gas at 25 Nm 3 /hr from the porous plug 4 placed at the bottom of the ladle, and the converter slag 5 in the immersion tube was discharged to the outside of the immersion tube. As a result, 80% of the surface area of the molten steel inside the immersion tube was exposed.
つぎに、溶鋼表面から1mの位置に配置した上
吹きランス６を用い、酸素分圧を0.02気圧に調整
した酸素ガスとアルゴンの混合ガスを、流量
25000Nm3／hrで溶鋼表面に吹きつけ、脱炭処理
を30分間行つた。 Next, using a top-blowing lance 6 placed 1 m from the molten steel surface, a mixed gas of oxygen gas and argon with the oxygen partial pressure adjusted to 0.02 atm was introduced at a flow rate.
Decarburization treatment was carried out for 30 minutes by spraying the surface of the molten steel at 25000Nm 3 /hr.
脱炭処理後の溶鋼の炭素含有量は0.003％、マ
ンガンは0.23％、溶鋼温度1600℃であつた。 After decarburization, the carbon content of the molten steel was 0.003%, the manganese content was 0.23%, and the molten steel temperature was 1600°C.
比較例１に用いた処理前溶鋼１は、250t転炉で
溶銑から炭素0.04％、マンガン0.25％に溶製した
溶鋼を取鍋２に未脱酸状態で出鋼したものであ
り、取鍋内溶鋼温度は1635℃であつた。その後、
取鍋下部に配置したポーラスプラグ４からアルゴ
ンガスを25Nm3／hr吹き込みつつ、溶鋼内に浸
漬管３を浸漬し、浸漬管内の転炉スラグ５を浸漬
管の外側に排出した。これにより、浸漬管内の溶
鋼表面は、面積比で80％が裸湯となつた。 The pre-processed molten steel 1 used in Comparative Example 1 is molten steel that has been melted into 0.04% carbon and 0.25% manganese from hot metal in a 250t converter and tapped into a ladle 2 in an undeoxidized state. The molten steel temperature was 1635°C. after that,
The immersion tube 3 was immersed in the molten steel while blowing argon gas at 25 Nm 3 /hr from the porous plug 4 placed at the bottom of the ladle, and the converter slag 5 in the immersion tube was discharged to the outside of the immersion tube. As a result, 80% of the surface area of the molten steel inside the immersion tube was exposed.
つぎに、溶鋼表面から1mの位置に配置した上
吹きランス６を用い、酸素分圧を0.6気圧に調整
した酸素ガスとアルゴンの混合ガスを、流量
25000Nm3／hrで溶鋼表面に吹きつけ、脱炭処理
を20分間行つた。 Next, using a top-blowing lance 6 placed 1 m from the molten steel surface, a mixed gas of oxygen gas and argon with an oxygen partial pressure adjusted to 0.6 atmospheres was introduced at a flow rate.
Decarburization treatment was performed for 20 minutes by spraying the surface of the molten steel at 25000Nm 3 /hr.
脱炭処理後の溶鋼の炭素含有量は0.021％、マ
ンガンは0.17％、溶鋼温度1610℃であつた。 After decarburization, the carbon content of the molten steel was 0.021%, the manganese content was 0.17%, and the molten steel temperature was 1610°C.
比較例２に用いた処理前溶鋼１は、250t転炉で
溶銑から炭素0.04％、マンガン0.25％に溶製した
溶鋼を取鍋２に未脱酸状態で出鋼したものであ
り、取鍋内溶鋼温度は1635℃であつた。 The pre-processed molten steel 1 used in Comparative Example 2 is molten steel that has been melted into 0.04% carbon and 0.25% manganese from hot metal in a 250t converter, and is tapped into a ladle 2 in an undeoxidized state. The molten steel temperature was 1635°C.
つぎに、取鍋内に30mm厚の転炉スラグを残留さ
せたまま、溶鋼表面から1mの位置に配置した上
吹きランスを用い、酸素分圧を0.1気圧に調整し
た酸素ガスとアルゴンの混合ガスを、流量
25000Nm3／hrで溶鋼表面に吹きつけ、脱炭処理
を20分間行つた。 Next, with the 30 mm thick converter slag remaining in the ladle, a mixed gas of oxygen gas and argon with the oxygen partial pressure adjusted to 0.1 atm using a top blowing lance placed 1 m from the molten steel surface. , the flow rate
Decarburization treatment was performed for 20 minutes by spraying the surface of the molten steel at 25,000 Nm 3 /hr.
脱炭処理後の溶鋼の炭素含有量は0.022％、マ
ンガン0.18％、溶鋼温度は1605℃であつた。 The carbon content of the molten steel after decarburization treatment was 0.022%, manganese 0.18%, and the molten steel temperature was 1605°C.
以上の如く、本発明方法を溶鋼脱炭処理に適用
することにより、安価に且つ容易に極低炭素鋼の
溶製が可能になつた。 As described above, by applying the method of the present invention to the decarburization treatment of molten steel, it has become possible to easily and inexpensively produce ultra-low carbon steel.
（発明の効果）
本発明によれば、従来の極低炭素鋼の溶製法と
比較して、高価な脱ガス設備等の改造及び新設は
ほとんどなく、単に溶製表面のスラグを減少せし
めること、吹きつけ混合ガスの酸素分圧を調整す
ることにより、30分間以内で、通常のRH真空脱
ガス装置を用いた場合と同様に炭素含有量50ppm
という極低炭素鋼の溶製も可能となつた。このよ
うに本発明によれば、従来法と比較して容易か
つ、確実に溶鋼の脱炭ができる。また、工業的規
模で正確な脱炭ができる等の優れた効果が得られ
る。(Effects of the Invention) According to the present invention, compared to the conventional melting method for ultra-low carbon steel, there is almost no need for modification or new installation of expensive degassing equipment, etc., and it is possible to simply reduce slag on the melting surface. By adjusting the oxygen partial pressure of the blown mixed gas, the carbon content can be reduced to 50ppm within 30 minutes, the same as when using a normal RH vacuum degassing device.
It has also become possible to produce ultra-low carbon steel. As described above, according to the present invention, molten steel can be decarburized more easily and reliably than conventional methods. Further, excellent effects such as accurate decarburization on an industrial scale can be obtained.
第１図は本発明の実施方法の一例を示す説明図
である。
１……溶鋼、２……取鍋、３……浸漬管、５…
…転炉スラグ、６……上吹ランス。
FIG. 1 is an explanatory diagram showing an example of a method of implementing the present invention. 1... Molten steel, 2... Ladle, 3... Immersion tube, 5...
...Converter slag, 6...Top blow lance.
Claims (1)
占める面積を、溶鋼表面積の20％以下に減少せし
めた、炭素含有量0.04〜0.02％の溶鋼表面に、酸
素分圧0.5〜0.01気圧に調整した酸化性ガスと不
活性ガスとの混合ガスを吹きつけ、溶鋼の酸化を
抑制しつつ溶鋼を脱炭し、炭素含有量0.02％以下
の溶鋼を溶製する極低炭素鋼の溶製方法。1. Adjust the oxygen partial pressure to 0.5 to 0.01 atm on the surface of molten steel with a carbon content of 0.04 to 0.02%, which reduces the area occupied by oxidizing slag on the surface of the steel in the ladle to 20% or less of the surface area of the molten steel. A method for producing ultra-low carbon steel that decarburizes molten steel by blowing a mixed gas of oxidizing gas and inert gas to suppress oxidation of the molten steel and produce molten steel with a carbon content of 0.02% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15345488A JPH024911A (en) | 1988-06-23 | 1988-06-23 | Method for refining ultra low carbon steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15345488A JPH024911A (en) | 1988-06-23 | 1988-06-23 | Method for refining ultra low carbon steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH024911A JPH024911A (en) | 1990-01-09 |
| JPH0512410B2 true JPH0512410B2 (en) | 1993-02-18 |
Family
ID=15562909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15345488A Granted JPH024911A (en) | 1988-06-23 | 1988-06-23 | Method for refining ultra low carbon steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH024911A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04362115A (en) * | 1991-06-06 | 1992-12-15 | Nippon Steel Corp | Decarburizing method for molten steel |
| JP4379152B2 (en) | 2004-02-27 | 2009-12-09 | コニカミノルタビジネステクノロジーズ株式会社 | Cleaning device and image forming apparatus |
-
1988
- 1988-06-23 JP JP15345488A patent/JPH024911A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH024911A (en) | 1990-01-09 |
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