JPH01159310A - Manufacture of low nitrogen stainless steel - Google Patents
Manufacture of low nitrogen stainless steelInfo
- Publication number
- JPH01159310A JPH01159310A JP28544487A JP28544487A JPH01159310A JP H01159310 A JPH01159310 A JP H01159310A JP 28544487 A JP28544487 A JP 28544487A JP 28544487 A JP28544487 A JP 28544487A JP H01159310 A JPH01159310 A JP H01159310A
- Authority
- JP
- Japan
- Prior art keywords
- blowing
- decarburization
- gas
- blown
- molten steel
- 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 25
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 20
- 239000010935 stainless steel Substances 0.000 title claims abstract description 20
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 18
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 238000007664 blowing Methods 0.000 claims abstract description 132
- 239000007789 gas Substances 0.000 claims abstract description 66
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 56
- 239000010959 steel Substances 0.000 claims abstract description 56
- 239000002184 metal Substances 0.000 claims abstract description 39
- 229910052751 metal Inorganic materials 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 30
- 238000003756 stirring Methods 0.000 claims abstract description 25
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 14
- 229910017082 Fe-Si Inorganic materials 0.000 claims abstract 4
- 229910017133 Fe—Si Inorganic materials 0.000 claims abstract 4
- 238000005261 decarburization Methods 0.000 claims description 73
- 239000003085 diluting agent Substances 0.000 claims description 10
- 238000007865 diluting Methods 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 4
- 229910052742 iron Inorganic materials 0.000 abstract 2
- 238000005262 decarbonization Methods 0.000 abstract 1
- 239000011261 inert gas Substances 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 238000010790 dilution Methods 0.000 description 8
- 239000012895 dilution Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 230000003068 static effect Effects 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〕 本発明は低窒素ステンレス鋼の製造方法に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing low nitrogen stainless steel.
ステンレス鋼の製造において高Ｃｒ銑を大気圧下で脱炭
吹錬する場合、溶銑中に大量の不活性ガスを撹拌ガスと
して吹き込む必要がある０通常使用し得るこの種のガス
としてはＮ。When decarburizing high Cr pig iron under atmospheric pressure in the production of stainless steel, it is necessary to blow a large amount of inert gas into the hot metal as a stirring gas.
及びＡｒがあるが、製造対象が低窒素ステンレス鋼であ
る場合、Ｎｓは鋼中Ｎ濃度を高めるため使用できず、こ
のため高価なＡｒを使用せざるを得ない、しかしｓ Ａ
ｒを大量に使用するため実際にはコスト的に問題がある
。このようなことから、低窒素ステンレス鋼の製造は。However, if the material to be manufactured is low nitrogen stainless steel, Ns cannot be used because it increases the N concentration in the steel, and therefore expensive Ar must be used.
Since a large amount of r is used, there is actually a cost problem. For this reason, the production of low-nitrogen stainless steel.
脱窒が容易な真空吹錬によるのが通常である。Vacuum blowing, which facilitates denitrification, is usually used.
本発明はこのような従来の問題に鑑みなされたもので、
大気圧下において、大量のＡｒガスを用いることなく低
コストで低窒素ステンレス鋼を製造することができる方
法を提供せんとするものである。The present invention was made in view of such conventional problems,
The present invention aims to provide a method that can produce low-nitrogen stainless steel at low cost under atmospheric pressure without using a large amount of Ar gas.
本発明者等は、脱炭時に詔ける撹拌用ガスとしてＮ！を
用いることを前提とし、溶鋼の脱窒方法について検討を
行った。この結果、脱炭終了後−Ｆｅ−８ｉ ｍ ｋｌ
等の脱酸剤を投入し、て大量のＡｒ底吹きによるリンス
処理を行うことが溶鋼の脱窒に非常に有効であることを
見い出した・
また０本発明者等は、転炉型容器による高Ｃｒ溶銑の脱
炭をＣｒ酸化ロスを抑えしかも短時間で行うことができ
る方法として、容器内の高ｃｒ溶銑に対し、上吹きラン
スから、不活性ガスで希釈した脱炭用０．を上吹きする
とともに、底吹き羽口から不活性ガスを吹き込んで溶銑
を強撹拌するようにした新たな方法を開発したが、この
ような脱炭方法により低窒素ステンレス鋼を製造する場
合、上記脱炭吹錬後の処理に加え、脱炭時の希釈ガスと
してＡｒを使用することが、鋼中Ｎの低減化により効果
的であることも見い出した。The present inventors discovered N! as a stirring gas that can be used during decarburization. We investigated a denitrification method for molten steel based on the assumption that it would be used. As a result, after decarburization -Fe-8i m kl
The present inventors have found that rinsing with a large amount of Ar bottom blowing is very effective for denitrifying molten steel. As a method for decarburizing high Cr hot metal in a short period of time while suppressing Cr oxidation loss, the high Cr hot metal in a container is blown with 0.0% decarburizer diluted with inert gas from a top blowing lance. We have developed a new method in which hot metal is top-blown and inert gas is blown in from the bottom-blowing tuyere to strongly stir the hot metal. However, when producing low-nitrogen stainless steel using this decarburization method, It has also been found that using Ar as a diluent gas during decarburization in addition to the treatment after decarburization blowing is more effective in reducing N in steel.
本発明はこのような知見に基づいてなされたもので、そ
の第１の特徴は、撹拌用ガスとしてＮ３を吹き込みつつ
含Ｃｒ溶銑を脱炭吹錬し。The present invention was made based on such findings, and its first feature is that Cr-containing hot metal is decarburized and blown while blowing N3 as a stirring gas.
該吹錬終了後、 Ｆｅ−８Ｌまたは紅等の脱酸剤を投入
し、溶鋼をＡｒにより底吹き撹拌するようにしたことに
ある。After the blowing is completed, a deoxidizing agent such as Fe-8L or Beni is added, and the molten steel is bottom-blown and stirred with Ar.
また、本発明の第２の特徴は、底吹き羽口と上吹きラン
スとを備えた容器内の含Ｃｒ溶銑に対し、上吹きランス
から、Ａｒで希釈した脱炭用Ｏ２を上吹きするとともに
、底吹き羽口からＮ、を吹き込んで溶銑を強情拌するこ
とにより脱炭吹錬し、該吹錬終了後、Ｆｅ−８１または
Ａｌ等の脱酸剤を投入し、溶鋼をＡｒにより底吹き撹拌
するようにしたことにある。A second feature of the present invention is that O2 for decarburization diluted with Ar is top-blown from a top-blowing lance to Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance. The molten metal is decarburized by blowing N from the bottom blowing tuyere to forcefully stir it, and after the blowing is finished, a deoxidizing agent such as Fe-81 or Al is introduced, and the molten steel is bottom blown with Ar. The reason is that it is stirred.
また１本発明の第３の特徴は、底吹き羽口と上吹きラン
スとを備えた容器内の含Ｃｒ溶銑に対し、上吹きランス
から、Ｎ２で希釈した脱炭用０３を上吹きするとともに
、底吹き羽口からＮ２を吹き込んで溶銑を強撹拌するこ
とにより脱炭吹錬を開始し、説、大途中で脱炭用０２の
希釈ガスをＮ２からＡｒに切換え、該吹錬終了後。A third feature of the present invention is that 03 for decarburization diluted with N2 is top-blown from a top-blowing lance to Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance. Decarburization blowing was started by blowing N2 from the bottom blowing tuyere to strongly stir the hot metal, and midway through, the diluent gas for decarburization 02 was switched from N2 to Ar, and after the blowing was completed.
Ｆｅ−８ｔまたはＡ／、等の脱酸剤を投入し、溶鋼をＡ
ｒにより底吹き撹拌するようにしたことにある。Add a deoxidizing agent such as Fe-8t or A/, and convert the molten steel to A.
The reason is that bottom-blown stirring is performed by r.
また１本発明の第４の特徴は、底吹き羽口と上吹きラン
スとを備えた容器内の含Ｃｒ溶銑に対し、上吹きランス
から、Ｎ８で希釈した脱炭用０３を上吹きするとともに
、底吹き羽口からＮ、を吹き込んで溶銑を強撹拌するこ
とにより脱炭吹錬を開始し、脱炭途中で溶湯撹拌用底吹
きガス及び脱炭用０２希釈ガスをＮ！からＡｒに切換え
、該吹錬終了後％Ｆｅ−８ｉまたはＡｌ等の脱酸剤を投
入し、溶鋼をＡｒにより底吹き撹拌するようにしたこと
にある。A fourth feature of the present invention is that 03 for decarburization diluted with N8 is top-blown from a top-blowing lance to Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance. Decarburization is started by blowing N from the bottom blowing tuyeres to strongly stir the hot metal, and during decarburization, the bottom blowing gas for stirring the molten metal and the 02 dilution gas for decarburization are injected with N! After the blowing was completed, a deoxidizing agent such as %Fe-8i or Al was added, and the molten steel was bottom-blown and stirred by Ar.
以下１本発明の詳細な説明する。The present invention will be explained in detail below.
一般に＊ Ｆｅ−８ｉや紅等は脱炭終了後のスラグ中の
Ｃｒ還元及び脱酸の目的で溶鋼中に投入されるが、本発
明ではこのような脱酸剤投入とともにｓ Ａｒによる底
吹き撹拌を実施するものであり、これによりＣｒ還元及
び脱酸に加え、鋼中Ｎが効果的ｌこ除去される。これは
。Generally *Fe-8i, red, etc. are added to molten steel for the purpose of reducing Cr and deoxidizing the slag after decarburization, but in the present invention, in addition to adding such a deoxidizing agent, bottom blowing stirring with sAr is used. This method not only reduces Cr and deoxidizes the steel, but also effectively removes N from the steel. this is.
Ｆｅ−８ｉ等の脱酸剤の投入により溶鋼が脱酸（７０〜
１５０ ｐｐｍ→５０ ｐｐｍ以下）されることに伴い
、Ｎが抜は易い状態になり、これをＡｒで撹拌すること
によりＮが溶鋼中から容易に抜け、鋼の脱窒がなされる
ことによるものである。Molten steel is deoxidized by adding a deoxidizing agent such as Fe-8i (70~
150 ppm → 50 ppm or less), N is easily removed, and by stirring this with Ar, N is easily removed from the molten steel, denitrifying the steel. be.
上記Ａｒの底吹きは１通常０．５〜５Ｎｍ３／分・溶鋼
ｔｏへ好ましくは１〜３ Ｎｍ２分・溶鋼ｔｏｎ、 ５
〜１０分間程度行われる。The above Ar bottom blowing is usually 0.5 to 5 Nm3/min to molten steel, preferably 1 to 3 Nm2 min, molten steel ton, 5
This will last approximately 10 minutes.
上述したように本発明者等は、大気圧下においてＣｒ酸
化ロスを抑え、しかも短時間で脱炭を行うことができる
方法として、底吹き羽口と上吹きランスとを備えた容器
内の高Ｃｒ溶銑に対し、上吹きランスから、不活性ガス
で希釈した脱炭用０．を上吹きするとともに、底吹き羽
口から不活性ガスを吹き込んで溶銑を強撹拌することを
内容とする新たな方法を創案した。以下、この脱炭法を
第１図の模式図に基づいて説明すると、まず、この方法
では次のように条件で脱炭処理がなされる。As mentioned above, the present inventors have developed a high-temperature system in a container equipped with a bottom blowing tuyere and a top blowing lance as a method that can suppress Cr oxidation loss and decarburize in a short time under atmospheric pressure. For Cr hot metal, 0.0. They devised a new method that involves top-blowing the molten metal and vigorously stirring the hot metal by blowing inert gas through the bottom-blowing tuyere. Hereinafter, this decarburization method will be explained based on the schematic diagram of FIG. 1. First, in this method, decarburization treatment is performed under the following conditions.
φ ０雪の供給は専ら上吹きランス（１）４に＝に！ｊ
から行い、０り底吹きは行わない。φ 0 Snow supply is exclusively to top blow lance (1) 4! j
Start from 0 and do not bottom blow.
■ 上吹きランス（１）力）らは、純ｏオではなく不活
性ガスで希釈した。ｌを供給する。■ The top blowing lance (1) was diluted with inert gas instead of pure oxygen. supply l.
■ 底吹き羽口（２）からは不活性ガスを吹き込んで強
撹拌する。■ Inert gas is blown through the bottom blowing tuyere (2) and stirred vigorously.
従来知られているＡＯＤ法では０．を炉底側の羽口から
吹き込む方法が採られているが１本発明者等の検討によ
れば、底吹きｏ３がＣｒ酸化ロスを増大させる大きな原
因であることが判った。すなわち、ｏ２底吹きでは溶鋼
静圧が加わるため００分圧が高くなり、この結果、脱炭
反応が阻害され、脱炭用ｏ３がＯｒを酸化させてしまう
。このため本脱炭法では０！底吹きは行わず、上吹きラ
ンス（１）から送酸を行う。In the conventionally known AOD method, 0. A method has been adopted in which O3 is blown into the furnace from the tuyere on the bottom side of the furnace.According to the study conducted by the present inventors, it has been found that bottom blowing O3 is a major cause of increasing Cr oxidation loss. That is, in O2 bottom blowing, molten steel static pressure is applied, so the 00 partial pressure becomes high, and as a result, the decarburization reaction is inhibited, and the decarburization O3 oxidizes Or. Therefore, in this decarburization method, 0! Oxidation is carried out from the top blowing lance (1) without bottom blowing.
しかし、この上吹きを単に純ｏ２で行うだけではｃｒ酸
化ロスを適切に防止し得ないことが判った。これは、脱
炭反応はランス送酸による火点においても最も激しく生
じるがｓ ＯＨだけの送酸ではこの部分の００分圧が非
常に高くなり、この結果脱炭反応が阻害され、０鵞がＣ
ｒを酸化させてしまうことによるものである。However, it has been found that simply performing this top blowing with pure O2 does not adequately prevent CR oxidation loss. This is because the decarburization reaction occurs most intensely at the flash point due to lance oxygen supply, but when only s OH is supplied, the partial pressure at this part becomes extremely high, and as a result, the decarburization reaction is inhibited and the zero C
This is due to the oxidation of r.
このため１本脱炭法では不活性ガスで希釈した０２を上
吹きするようにし、これ屹よって火点における００分圧
を下げ脱炭反応を促進させるようにしたものである。な
お、上吹きランスからは処理時間を短くするため大量送
酸することが好ましい。For this reason, in the single-tube decarburization method, 02 diluted with an inert gas is top-blown, thereby lowering the 00 partial pressure at the fire point and promoting the decarburization reaction. Note that it is preferable to supply a large amount of oxygen from the top blowing lance in order to shorten the treatment time.
さらに本脱炭法では、溶湯と上吹き０りとの混合を促進
させるため、底吹き羽口（２）から不活性ガスを吹き込
み、溶湯を強撹拌するものであり、この底吹き不活性ガ
スによる強撹拌と、上記ランスによる不活性ガス希釈０
鵞の上吹きとの組み合わせによりＣｒ酸化ロスを抑えた
効率的な脱炭処理が可能となる。Furthermore, in this decarburization method, in order to promote the mixing of the molten metal and the top-blown gas, inert gas is blown into the bottom-blown tuyere (2) to strongly stir the molten metal. strong stirring and inert gas dilution with the above lance 0
Combination with top blowing enables efficient decarburization treatment with suppressed Cr oxidation loss.
溶湯を強撹拌するためには大量の不活性ガスを吹き込む
必要がある。具体的にはｍｃｒ酸化ロスを１チ以下とす
るためには０．５Ｎｍ３／分・溶湯ｔｏｎ以上、またｃ
ｒ酸化ロスを０．５％以下とするためにはＩ Ｎｍ３／
分・溶湯ｔｏｎ以上の量のガスを底吹きする必要がある
。但し、ガス量が多すぎると溶湯が飛散して問題を生じ
る恐れがあり、このため本脱炭法では０．５〜５ Ｎｍ
ｓ／分・溶湯ｔｏｎ、好ましくは１〜３Ｎ♂／分・溶湯
ｔｏｎ程度の量のガスが吹き込まれる。In order to strongly stir the molten metal, it is necessary to blow in a large amount of inert gas. Specifically, in order to reduce the mcr oxidation loss to 1 inch or less, 0.5Nm3/min/molten metal ton or more, and c
In order to reduce the oxidation loss to 0.5% or less, I Nm3/
It is necessary to bottom-blow gas in an amount of more than 1000 ton per ton of molten metal. However, if the amount of gas is too large, the molten metal may scatter and cause problems, so in this decarburization method, the amount of gas is 0.5 to 5 Nm.
Gas is blown in an amount of approximately 1 to 3 N♂/min/ton of molten metal, preferably 1 to 3 N♂/min/ton of molten metal.
本発明法によりこのような脱炭法を利用して低窒素ステ
ンレス鋼を製造する場合、第１の方法として、脱炭吹錬
時の底吹きガスとしてはＮ２を使用するものの、脱炭用
への希釈ガスとしてはＡｒガスを使用する。脱炭吹錬で
はランスの火点部分でＮの吸収が最も激しいことから、
Ｎを希釈ガスとして使用すると大量のＮが溶湯中に溶は
込んでしまう。そこで。When manufacturing low-nitrogen stainless steel using such a decarburization method according to the method of the present invention, the first method is to use N2 as the bottom blowing gas during decarburization blowing, but to use N2 for decarburization. Ar gas is used as the dilution gas. During decarburization blowing, the absorption of N is most intense at the hot point of the lance.
If N is used as a diluent gas, a large amount of N will dissolve into the molten metal. Therefore.
本発明では比較的少量で済む希釈ガスのみをＡｒとし、
Ａｒ使用量に較べ窒素濃度の上昇を効果的に抑えるよ
うにしたものである。そして、このような脱炭吹錬終了
後、脱窒処理を行う。In the present invention, Ar is used as the only diluent gas that requires a relatively small amount.
This effectively suppresses the increase in nitrogen concentration compared to the amount of Ar used. After completing such decarburization blowing, denitrification treatment is performed.
また１本発明者等は、鋼中Ｎに関し、脱炭反応が活発な
時期には鋼中Ｎが低く、脱炭速度が低下してくる時期か
ら鋼中Ｎが著しく上昇する事を見い出した。これは、脱
炭反応により発生するＣＯガスが鋼中Ｎを吸収し放出す
るためである。In addition, the present inventors have found that N in steel is low when the decarburization reaction is active, and increases significantly from the time when the decarburization rate decreases. This is because the CO gas generated by the decarburization reaction absorbs and releases N in the steel.
ここで、脱炭速度は鋼中（Ｃ）濃度が高い程遠（、この
ため脱炭用０３の希釈ガスさらには底吹ガスとして、当
初はＮ３ガスを使用しておき、脱炭途中で鋼中（Ｃ）が
低くなったときからＮ！をＡｒに切換えて脱炭を続ける
ことにより、製造コストを適切に低減させることができ
る。Here, the decarburization rate increases as the (C) concentration in the steel increases (for this reason, N3 gas is initially used as the diluent gas for decarburization 03 and also as the bottom blowing gas, and during decarburization the steel By switching N! to Ar and continuing decarburization from when the medium (C) becomes low, manufacturing costs can be appropriately reduced.
すなわち１本発明法により脱炭用０！を不活°性ガスで
希釈して行う脱炭法を利用して低窒素ステンレス鋼を製
造する場合の第２の方法は、上吹きランスからＮ２で希
釈した脱炭用０曹を上吹きするとともに、底吹き羽口か
らＮ１を吹き込んで溶銑を強撹拌することにより脱炭吹
錬を開始し、脱炭途中で脱炭用０２の希釈ガスをＮ、か
らＡｒに切換え、該吹錬終了後、Ｆｅ−５ｉまたは紅等
の脱酸剤を投入し、溶鋼をＡｒにより底吹き撹拌するも
のである。In other words, 1. 0 for decarburization by the method of the present invention! The second method for manufacturing low-nitrogen stainless steel using the decarburization method, which involves diluting the steel with an inert gas, is to top-blowing zero carbon dioxide diluted with N2 from a top-blowing lance. At the same time, decarburization blowing was started by blowing N1 from the bottom blowing tuyere to strongly stir the hot metal, and in the middle of decarburization, the diluent gas for decarburization 02 was switched from N to Ar, and after the blowing was completed. A deoxidizing agent such as , Fe-5i or Beni is added, and the molten steel is stirred by bottom blowing with Ar.
さ、らに、第３の方法は上吹きランスから。Well, the third method is from the top blow lance.
Ｎ３で希釈した脱炭用０３を上吹きするとともに。At the same time as top blowing 03 for decarburization diluted with N3.
底吹き羽口からＮ、を吹き込んで溶銑を強撹拌すること
により脱炭吹錬を開始し、脱炭途中で溶湯撹拌用底吹き
ガス及び脱炭用０雪の希釈ガスをＮ３からＡｒに切換え
、該吹錬終了後５ＦＥ１−ｓｔまたはＭ等の脱酸剤を投
入し、溶鋼をＡｒにより底吹き撹拌するものである。Decarburizing is started by blowing N from the bottom blowing tuyere to strongly stir the hot metal, and during decarburization, the bottom blowing gas for stirring the molten metal and the diluent gas for decarburizing are switched from N3 to Ar. After the blowing is completed, a deoxidizing agent such as 5FE1-st or M is added, and the molten steel is bottom-blown and stirred with Ar.
ここで、脱炭用伽希釈ガス及び底吹ガスのＮ、→Ａｒの
切換時期は、溶鋼中［”Ｃ］量に基づいて行うことが好
ましく、具体的には、第３図に示すように溶鋼中〔Ｃ）
：３１ｋが０．８〜２．（１ｗｔ％の範囲に窓いて、
Ｎ２→Ａｒの切換を行うことが好ましい自上記切換の時
期が早過ぎるとそれだけ高価なＡｒガスを多量に使用し
なければならず、コスト高となる。このため、切換は溶
鋼中〔Ｃ〕が２．０ｗｔ％以下となった時期に行うこと
が好ましい、一方、切換時期が遅過ぎる（Ｃ濃度が低く
なり過ぎる）と、第３図に示すように十分な脱窒効果が
得られず、このため、切換は溶鋼中〔Ｃ〕が０．８ｗｔ
％以上にある時点で行うことが好ましい。Here, it is preferable to switch the timing of N and →Ar for the decarburization dilution gas and the bottom blowing gas based on the amount of [C] in the molten steel. Specifically, as shown in Fig. 3, During molten steel [C]
:31k is 0.8~2. (with a window of 1 wt%,
It is preferable to switch from N2 to Ar. If the switching is performed too early, a large amount of expensive Ar gas must be used, resulting in high costs. For this reason, it is preferable to make the switch when the [C] content in the molten steel is 2.0wt% or less.On the other hand, if the switch is made too late (the C concentration becomes too low), as shown in Figure 3, Sufficient denitrification effect could not be obtained, and for this reason, the switching was performed with 0.8wt of [C] in the molten steel.
% or more.
実施例 １゜
上吹きランス及び底吹き羽口を有する転炉型容器を用い
、以下の（Ａ）〜（Ｅ）の方法により、高Ｃｒ溶銑を脱
炭吹錬した後、 Ａｒリンス（Ｆｅ−８ｔ投入＋Ａｒ
底吹き）を実施し、Ｃｒ ： １８’％、 Ｃ： ０．
０５ ％のステンレス溶鋼を製造した。Example 1 Using a converter type vessel having a top blowing lance and a bottom blowing tuyere, high Cr hot metal was decarburized and blown by the following methods (A) to (E), followed by Ar rinsing (Fe- 8t input + Ar
Cr: 18'%, C: 0.
05% stainless steel was produced.
（４）脱炭吹錬上吹きガス： ０２ ＋Ｎａ （希釈）
底吹きガス：Ｎ２（２挽−７分・溶鋼ｔｏｎ ）Ａｒリ
ンス 底吹きガス： Ａ ｒ （０，１Ｎｍ３／ｆｊ
−・溶鋼ｔｏｎ ）（Ｂ）脱炭吹錬 上吹きガス： Ｃ
ｈ＋Ｎｓ （希 釈）底吹きガス：Ｎｚ（２Ｎｍシ分・
溶鋼ｔｏｎ）Ａｒリンス 底吹きガス： Ａｒ（０，５
Ｎｍｙ分・溶鋼ｔｏｎ）に）脱炭吹錬 上吹きガス：
Ｏｘ＋Ｎｚ （希 釈）底吹きガス ：Ｎ、（２持ゆ
分・溶鋼ｔｏｎ）Ａｒリンス 底吹きガス ： Ａｒ（
ＩＮｍ／９・溶鋼ｔｏｎ）ρ）脱炭吹錬 上吹きガス：
Ｏｓ ＋Ｎａ （希 釈）底吹きガス： Ｎ！（２Ｎ
ｒｌ／分・溶鋼ｔｏｎ）Ａｒリンス 底吹きガス： Ａ
ｒ（ｚＮＪ／＋・溶鋼ｔｏｎ）（ト）脱炭吹錬 上吹き
ガス：０２ ＋ Ａｒ （希 釈）底吹きガス： Ｎ２
（２Ｎｍｎ ・溶鋼ｔｏｎ）Ａｒリンス 底吹きガス
：Ａｒ（２Ｎｉン外・溶鋼ｔｏｎ）第２図はＡｒリンス
中の脱窒速度番こ及ぼす底吹きＡｒガスｒ影響を示した
ものである。(4) Top-blown gas for decarburization blowing: 02 +Na (diluted)
Bottom blowing gas: N2 (2 grinding - 7 minutes, molten steel ton) Ar rinse Bottom blowing gas: Ar (0.1Nm3/fj
-・molten steel ton) (B) Decarburization blowing Top blowing gas: C
h+Ns (dilution) bottom-blown gas: Nz (2Nm
Molten steel ton) Ar rinse Bottom blowing gas: Ar (0,5
(Nmy min/ton of molten steel) Decarburization blowing Top blowing gas:
Ox+Nz (diluted) bottom-blown gas: N, (2 ton of molten steel) Ar rinse Bottom-blown gas: Ar (
INm/9・molten steel ton) ρ) Decarburization blowing Top blowing gas:
Os +Na (diluted) bottom-blown gas: N! (2N
rl/min/ton of molten steel) Ar rinse Bottom blowing gas: A
r (zNJ/+・molten steel ton) (g) Decarburization blowing Top blowing gas: 02 + Ar (diluted) Bottom blowing gas: N2
(2Nmn/molten steel ton) Ar rinsing Bottom-blown gas: Ar (2Nin outside/molten steel ton) Figure 2 shows the effect of bottom-blown Ar gas r on the denitrification rate during Ar rinsing.
これによれば、いずれの場合もＡｒ ＩＪンスにより溶
鋼の脱窒が効果的になされているが。According to this, in all cases, denitrification of molten steel is effectively achieved by Ar IJ.
特にＡｒガス量が２Ｎｍ”／ｆｆ・溶鋼ｔｏｎであるρ
）の場合、リンス時間４〜５分でほぼ目標レベルである
Ｎ：５００〜６００ ｐｐｍに達している。また、脱炭
時に０２の希釈ガスとしてＡｒを使用した（６）の場合
、脱炭終了時のＮ濃度が体）〜■）の場合の約半分の１
１０００ｐｐ程度であり、このため、より短時間のＡｒ
ＩＪンスで上記目標レベルに達している。Especially when the Ar gas amount is 2Nm”/ff・molten steel ton
), the target level of N: 500 to 600 ppm was almost reached in 4 to 5 minutes of rinsing time. In addition, in case (6) where Ar was used as the diluent gas for 02 during decarburization, the N concentration at the end of decarburization was approximately half of that in cases)
It is about 1000pp, and therefore the Ar
IJN has reached the above target level.
実施例 ２
上吹きランス及び底吹き羽口を有する転炉型容器を用い
、以下のケ）、（（ロ）の方法により、高Ｃｒ溶銑を脱
炭吹錬した後％Ａｒ ＩＪランスＦｅ−ｓｉ投入＋Ａｒ
底吹き）を実施し、Ｃｙ：１８％、Ｃ：０．Ｏｎのステ
ンレス溶鋼を製造した。Example 2 Using a converter type vessel having a top-blowing lance and a bottom-blowing tuyere, high Cr hot metal was decarburized and blown by the following methods (i) and (b). Input + Ar
(bottom blowing), Cy: 18%, C: 0. On's stainless steel molten steel was manufactured.
ピ）脱炭吹錬上吹きガス：脱炭用０１の希釈ガスとして
脱炭初期穐を
用い、吹錬途中の種
々の溶鋼中〔Ｃ〕値の
時点でＮ２をＡｒに切
換えた。B) Top-blowing gas for decarburization blowing: As the diluent gas for decarburization 01, ash was used at the initial stage of decarburization, and N2 was switched to Ar at various [C] values in the molten steel during blowing.
Ａｒリンス Ａｒ供給； ２Ｎが・溶鋼ｔｏｎで５分間
実施
（２））脱炭吹錬 上吹きガス：脱炭用０２の希釈ガス
及び底吹きガスとし
て脱炭初期Ｎ２を用い。Ar rinsing Ar supply; 2N carried out in a ton of molten steel for 5 minutes (2)) Decarburization blowing Top blowing gas: Use N2 at the initial stage of decarburization as the dilution gas and bottom blowing gas for 02 for decarburization.
吹錬途中の種々の溶 鋼中〔Ｃ〕の時点でＮ雪 をＡｒに切換えた。Various types of melting during blowing N snow at steel medium [C] was switched to Ar.
Ａｒリンス Ａｒ供給：２Ｎｍ／分−溶鋼ｔｏｎで５分
間実施
第３図は、脱炭吹錬終了時の溶鋼［’Ｎ］に及ぼす脱炭
用偽希釈ガス及び底吹きガスのガス種切換時期の影響を
示すものである・第１表はｓ Ａｒ リンス後の溶鋼［
”Ｎ］濃度を示すもの（脱炭吹錬中のＮ３→Ａｒの切換
は溶鋼（Ｃ）＝１％で実施した）で、本発明によれば２
００ ｐｐｍ以下の低Ｎステンレス鋼が容易に得られる
ことが判る。Ar rinsing Ar supply: 2 Nm/min - carried out for 5 minutes at ton of molten steel Figure 3 shows the effect of the timing of switching the gas type of the false dilution gas for decarburization and the bottom blowing gas on the molten steel ['N] at the end of decarburization blowing.・Table 1 shows the effects of s Ar rinsing on molten steel [
``N'' concentration (switching from N3 to Ar during decarburization blowing was carried out at molten steel (C) = 1%), and according to the present invention, 2
It can be seen that a low N stainless steel of 0.00 ppm or less can be easily obtained.
第 １ 表
〔発明の効果〕
以上述べた本発明によれば、大量のＡｒガスを用いるこ
となく低コストで低窒素ステンレス鋼を製造することが
でき、また本願第２．第３及び第４の発明番こよれば、
このような効果に加え、低窒素ステンレス鋼をＣｒ酸化
ロスを抑えしかも短時間で製造できる効果がある。Table 1 [Effects of the Invention] According to the present invention described above, low-nitrogen stainless steel can be manufactured at low cost without using a large amount of Ar gas. According to the third and fourth invention numbers,
In addition to these effects, there is an effect that low nitrogen stainless steel can be produced in a short time while suppressing Cr oxidation loss.
ｔｌＥｘ図は本発明法において行われる脱炭処理法を模
式的に示す説明図である。第２図はＡｒ ＩＪラン中の
脱窒速度に及ぼす底吹きＡｒガス量の影響を示すもので
ある。第３図は脱炭吹錬に於いて、上吹き希釈ガス、底
吹きガス種をＮ２からＡｒへ変更した時の溶鋼〔Ｃ〕値
と吹錬終了後の溶鋼〔Ｎ〕値の関係を示すものである。
図において、（１）は上吹きランス、（２）は底吹き羽
口である。The tlEx diagram is an explanatory diagram schematically showing the decarburization treatment method performed in the method of the present invention. FIG. 2 shows the effect of bottom-blown Ar gas amount on denitrification rate during Ar IJ run. Figure 3 shows the relationship between the molten steel [C] value and the molten steel [N] value after blowing when the top blowing dilution gas and bottom blowing gas types are changed from N2 to Ar during decarburization blowing. It is something. In the figure, (1) is a top blowing lance, and (2) is a bottom blowing tuyere.
Claims (4)
銑を脱炭吹錬し、該吹錬終了後、Ｆｅ−ＳｉまたはＡｌ
等の脱酸剤を投入し、溶鋼をＡｒにより底吹き撹拌する
ことを特徴と する低窒素ステンレス鋼の製造方法。(1) Cr-containing hot metal is decarburized by blowing while blowing N_2 as a stirring gas, and after the blowing is finished, Fe-Si or Al
A method for producing low-nitrogen stainless steel, which comprises adding a deoxidizing agent such as the like, and bottom-blowing stirring the molten steel with Ar.
Ｃｒ溶銑に対し、上吹きラン スから、Ａｒで希釈した脱炭用Ｏ＿２を上吹きするとと
もに、底吹き羽口からＮ＿２を吹き込んで溶銑を強撹拌
することにより脱炭 吹錬し、該吹錬終了後、Ｆｅ−ＳｉまたはＡｌ等の脱酸
剤を投入し、溶鋼をＡｒにより底 吹き撹拌することを特徴とする低窒素ス テンレス鋼の製造方法。(2) O_2 for decarburization diluted with Ar is top-blown from the top-blowing lance onto the Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance, and N_2 is being injected from the bottom-blowing tuyere. A low nitrogen method characterized by decarburizing blowing by blowing and strongly stirring the hot metal, and after the blowing is completed, a deoxidizing agent such as Fe-Si or Al is added, and the molten steel is bottom-blown and stirred with Ar. Method of manufacturing stainless steel.
Ｃｒ溶銑に対し、上吹きランス から、Ｎ＿２で希釈した脱炭用Ｏ＿２を上吹きするとと
もに、底吹き羽口からＮ＿２を吹き込んで溶銑を強撹拌
することにより脱炭吹 錬を開始し、脱炭途中で脱炭用Ｏ＿２希釈ガスをＮ＿２
からＡｒに切換え、該吹錬終了後、Ｆｅ−ＳｉまたはＡ
ｌ等の脱酸剤を投入し、溶鋼をＡｌにより底吹き撹拌す
ることを特 徴とする低窒素ステンレス鋼の製造方法。(3) O_2 for decarburization diluted with N_2 is top-blown from the top-blowing lance onto the Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance, and N_2 is also being blown from the bottom-blowing tuyere. Decarburization blowing is started by blowing in and strongly stirring the hot metal, and during decarburization, O_2 diluent gas for decarburization is replaced with N_2.
After the blowing, the Fe-Si or A
A method for producing low-nitrogen stainless steel, which comprises adding a deoxidizing agent such as Al, and bottom-blowing the molten steel with Al.
Ｃｒ溶銑に対し、上吹きランス から、Ｎ＿２で希釈した脱炭用Ｏ＿２を上吹きするとと
もに、底吹き羽口からＮ＿２を吹き込んで溶銑を強撹拌
することにより脱炭吹 錬を開始し、脱炭途中で溶湯撹拌用底吹 きガス及び脱炭用Ｏ＿２希釈ガスをＮ＿２からＡｒにに
切換え、該吹錬終了後、Ｆｅ−ＳｉまたはＡｌ等の脱酸
剤を投入し、溶鋼をＡｒにより底吹き撹拌することを特
徴とする低窒素 ステンレス鋼の製造方法。(4) O_2 for decarburization diluted with N_2 is top-blown from the top-blowing lance onto the Cr-containing hot metal in a vessel equipped with a bottom-blowing tuyere and a top-blowing lance, and N_2 is also being blown from the bottom-blowing tuyere. Decarburization blowing is started by blowing in and strongly stirring the hot metal, and during decarburization, the bottom blowing gas for stirring the molten metal and the O_2 diluting gas for decarburization are switched from N_2 to Ar, and after the blowing is completed, Fe- A method for producing low-nitrogen stainless steel, which comprises adding a deoxidizing agent such as Si or Al, and bottom-blowing the molten steel with Ar.
Priority Applications (17)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62285444A JP2674041B2 (en) | 1987-09-17 | 1987-11-13 | Manufacturing method of low nitrogen stainless steel |
| CA000576818A CA1333663C (en) | 1987-09-09 | 1988-09-08 | Method of decarburizing high cr molten metal |
| US07/320,270 US5047081A (en) | 1987-09-09 | 1988-09-09 | Method of decarburizing high chromium molten metal |
| AU23057/88A AU604974B2 (en) | 1987-09-10 | 1988-09-09 | Process for producing molten stainless steel |
| AT88907783T ATE107706T1 (en) | 1987-09-10 | 1988-09-09 | METHOD OF MAKING MOLTEN STAINLESS STEEL. |
| BR888807201A BR8807201A (en) | 1987-09-10 | 1988-09-09 | METHOD OF PRODUCTION OF STAINLESS STEEL IN REDUCING FUSION FUSION |
| DE3850394T DE3850394T2 (en) | 1987-09-10 | 1988-09-09 | METHOD FOR PRODUCING MELTED STAINLESS STEEL. |
| AT88907784T ATE103006T1 (en) | 1987-09-09 | 1988-09-09 | PROCESS FOR DECARBURIZING HIGH CHROMIUM PIG IRON. |
| US07/362,418 US4944799A (en) | 1987-09-10 | 1988-09-09 | Method of producing stainless molten steel by smelting reduction |
| EP88907784A EP0331751B1 (en) | 1987-09-09 | 1988-09-09 | PROCESS FOR DECARBURIZING HIGH-Cr MOLTEN PIG IRON |
| PCT/JP1988/000909 WO1989002479A1 (en) | 1987-09-09 | 1988-09-09 | Process for decarburizing high-cr molten pig iron |
| DE3888518T DE3888518T2 (en) | 1987-09-09 | 1988-09-09 | METHOD FOR THE DECARBONIZING OF HIGH CHROMED PIG IRON. |
| BR888807195A BR8807195A (en) | 1987-09-09 | 1988-09-09 | PROCESS FOR DECARBURIZING METAL MELTED WITH HIGH CHROME CONTENT |
| CN88107053A CN1013280B (en) | 1987-09-09 | 1988-09-09 | Method of decarburizing high cr molten metal |
| EP88907783A EP0355163B1 (en) | 1987-09-10 | 1988-09-09 | Process for producing molten stainless steel |
| AU23058/88A AU619488B2 (en) | 1987-09-09 | 1988-09-09 | Process for decarburizing high-cr molten pig iron |
| PCT/JP1988/000910 WO1989002478A1 (en) | 1987-09-10 | 1988-09-09 | Process for producing molten stainless steel |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62-231042 | 1987-09-17 | ||
| JP23104287 | 1987-09-17 | ||
| JP62285444A JP2674041B2 (en) | 1987-09-17 | 1987-11-13 | Manufacturing method of low nitrogen stainless steel |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9046924A Division JP2751924B2 (en) | 1987-09-17 | 1997-02-17 | Manufacturing method of low nitrogen stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01159310A true JPH01159310A (en) | 1989-06-22 |
| JP2674041B2 JP2674041B2 (en) | 1997-11-05 |
Family
ID=26529665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62285444A Expired - Fee Related JP2674041B2 (en) | 1987-09-09 | 1987-11-13 | Manufacturing method of low nitrogen stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2674041B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8104792B2 (en) | 2005-06-08 | 2012-01-31 | Ashimori Industry Co., Ltd. | Airbag device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56130416A (en) * | 1980-03-19 | 1981-10-13 | Nippon Steel Corp | Steel making method |
| JPS57110608A (en) * | 1980-12-26 | 1982-07-09 | Kawasaki Steel Corp | Method for deoxidation in bottom blown converter |
| JPS62130210A (en) * | 1985-11-30 | 1987-06-12 | Kawasaki Steel Corp | Production of stainless steel |
-
1987
- 1987-11-13 JP JP62285444A patent/JP2674041B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56130416A (en) * | 1980-03-19 | 1981-10-13 | Nippon Steel Corp | Steel making method |
| JPS57110608A (en) * | 1980-12-26 | 1982-07-09 | Kawasaki Steel Corp | Method for deoxidation in bottom blown converter |
| JPS62130210A (en) * | 1985-11-30 | 1987-06-12 | Kawasaki Steel Corp | Production of stainless steel |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8104792B2 (en) | 2005-06-08 | 2012-01-31 | Ashimori Industry Co., Ltd. | Airbag device |
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| Publication number | Publication date |
|---|---|
| JP2674041B2 (en) | 1997-11-05 |
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