JPH0317216A - Production of clean steel - Google Patents
Production of clean steelInfo
- Publication number
- JPH0317216A JPH0317216A JP15019589A JP15019589A JPH0317216A JP H0317216 A JPH0317216 A JP H0317216A JP 15019589 A JP15019589 A JP 15019589A JP 15019589 A JP15019589 A JP 15019589A JP H0317216 A JPH0317216 A JP H0317216A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- molten steel
- converter
- gas
- ladle
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 109
- 239000010959 steel Substances 0.000 title claims abstract description 109
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000007789 gas Substances 0.000 claims abstract description 39
- 238000010079 rubber tapping Methods 0.000 claims abstract description 34
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 28
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 10
- 239000002893 slag Substances 0.000 abstract description 24
- 238000007664 blowing Methods 0.000 abstract description 5
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 6
- 238000007670 refining Methods 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000007872 degassing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 229910000423 chromium oxide Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241000219112 Cucumis Species 0.000 description 1
- 235000015510 Cucumis melo subsp melo Nutrition 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910000604 Ferrochrome Inorganic materials 0.000 description 1
- 229910000617 Mangalloy Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- FJJCIZWZNKZHII-UHFFFAOYSA-N [4,6-bis(cyanoamino)-1,3,5-triazin-2-yl]cyanamide Chemical compound N#CNC1=NC(NC#N)=NC(NC#N)=N1 FJJCIZWZNKZHII-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- UOUJSJZBMCDAEU-UHFFFAOYSA-N chromium(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[Cr+3].[Cr+3] UOUJSJZBMCDAEU-UHFFFAOYSA-N 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 101150032700 pprA gene Proteins 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、極低窒素鋼等のような清浄鋼を溶製するため
の清浄鋼の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing clean steel, such as ultra-low nitrogen steel.
［従来の技術］
転炉出鋼された溶鋼は、多量の溶存［０］を含むため、
出鋼時またはそれ以降の二次精錬時に、溶鋼に金属アル
ミニウム等の脱酸剤を添加して、脱酸処理される。脱酸
処理された溶鋼は、その後、種々の処理工程を経て、鋳
造される。[Prior art] Since molten steel tapped from a converter contains a large amount of dissolved [0],
During tapping or subsequent secondary refining, a deoxidizing agent such as metallic aluminum is added to the molten steel to perform deoxidation treatment. The deoxidized molten steel is then subjected to various treatment steps and then cast.
近時、極低窒素鋼および極低燐鋼等の清浄鋼の需要が増
大している。清浄鋼を製造する場合は、［Ｎ］．［Ｐ］
等の特定の元素を極微量レベルまで低減するため、下記
の条件を満たす必要がある。Recently, the demand for clean steel such as ultra-low nitrogen steel and ultra-low phosphorus steel has been increasing. When manufacturing clean steel, [N]. [P]
In order to reduce specific elements such as to trace amounts, the following conditions must be met.
（１）スラグ中に含まれる酸化鉄の合計ｆｆｉ（以下、
（Ｔ−Ｆｅ）という）を低減し、溶鋼の再酸化を防止す
る。(1) Total ffi of iron oxide contained in slag (hereinafter referred to as
(referred to as T-Fe)) and prevents reoxidation of molten steel.
（２）溶鋼が大気によって再酸化される機会を減らす。(2) Reduce the chance of molten steel being reoxidized by the atmosphere.
（３）溶鋼が取鍋耐火物によって汚染されることを防止
する。(3) Preventing molten steel from being contaminated by ladle refractories.
しかしながら、上記（１）の条件を満たすために、例え
ば、転炉内で溶鋼を脱酸処理した後に出鋼（既脱酸出鋼
）してスラグの（Ｔ−Ｆｅ）を１０重量％以下に低減す
ると、出鋼溶鋼が窒素を吸収しやすくなり、窒素ビック
アップが生じる。However, in order to satisfy the above condition (1), for example, the molten steel is deoxidized in a converter and then tapped (deoxidized tapped steel) to reduce the (T-Fe) in the slag to 10% by weight or less. If it is reduced, the tapped molten steel will easily absorb nitrogen, resulting in a nitrogen surprise.
このため、極低窒素鋼を溶製する場合は、溶鋼を脱酸処
理することなく出鋼（未脱酸出ｆｆＩ４） Ｌ、その後
の二次精練工程において溶鋼を脱酸する。Therefore, when producing ultra-low nitrogen steel, the molten steel is tapped (undeoxidized ffI4) without being deoxidized, and the molten steel is deoxidized in the subsequent secondary refining process.
ところが、未脱酸出鋼すると、鍋内に高レベル（Ｔ−Ｆ
ｅ）の転炉スラグが流出し、溶鋼が鍋内で再度酸化され
るという問題点がある。このため、未脱酸出鋼直後にス
ラグドラッガー又はバキュームスラグクリーナ等を用い
て鍋内に流出した転炉スラグを除表し、溶鋼の再酸化を
防止していた。However, when undeoxidized steel is extracted, a high level (T-F) remains in the pot.
There is a problem in e) that the converter slag flows out and the molten steel is oxidized again in the ladle. For this reason, the converter slag that has flowed into the ladle is removed using a slag dragger or a vacuum slag cleaner immediately after undeoxidized steel is tapped to prevent reoxidation of the molten steel.
〔発明が解決しようとする課題ゴ
しかしながら、転炉から未脱酸出鋼すると、溶鋼の窒素
ビックアップを防止することはできるが、その後の工程
で溶鋼を脱酸処理しなければならず、ＲＨ脱ガス精錬等
の二次精錬における処理負担が増大する。特に、二次精
錬により溶鋼中Ｔ ｏｔａｌ［０］を２ ０ ｐｐｒＡ
以下に低減する場合は、処理コストが増大し、清浄鋼を
安価かつ容易に製造することができない。[Problems to be Solved by the Invention] However, if undeoxidized steel is extracted from a converter, nitrogen surprise in the molten steel can be prevented, but the molten steel must be deoxidized in the subsequent process, and RH The processing burden in secondary refining such as degassing refining increases. In particular, T total [0] in molten steel is reduced to 20 pprA through secondary refining.
If it is reduced below, the processing cost increases and clean steel cannot be manufactured easily and cheaply.
また、未脱酸出鋼においては、出鋼直後の除滓作業が必
須であり、出鋼から取鍋搬出に至るまでの一連の作業に
多大の労力を要する。In addition, in undeoxidized tapped steel, slag removal work is essential immediately after tapping, and a series of operations from tapping to carrying out the ladle requires a great deal of effort.
更に、除滓作業後も若干量の転炉スラグが鍋内に残留す
るが、この残留転炉スラグが鋳造工程まで持ち込まれ、
鋳造中にスラグ・メタル反応によってアルミナやシリカ
が生威されるという不都合を生じる。Furthermore, a small amount of converter slag remains in the pot even after the slag removal work, but this residual converter slag is carried into the casting process.
The disadvantage is that alumina and silica are destroyed by slag-metal reaction during casting.
この発明は、上記事情に鑑みてなされたものであって、
極低窒素鋼等のような清浄鋼を溶製する場合に、窒素ビ
ックアップを防止しつつ未脱酸出鋼の欠点を解消するこ
とができ、安価かつ容易な清浄鋼の製造方法を提供する
ことを目的とする。This invention was made in view of the above circumstances, and
To provide an inexpensive and easy method for producing clean steel, which can eliminate the drawbacks of undeoxidized steel while preventing nitrogen surprise when producing clean steel such as ultra-low nitrogen steel. The purpose is to
［課題を解決するための手段］
発明者等は、出鋼口から鍋に至るまでの領域を大気から
遮断した状態で出鋼するいわゆる無酸化出鋼装置を開発
実用化し、既脱酸出鋼時における溶鋼の酸化防止に成功
している。そこで、発明者等は、この無酸化出鋼装置を
利用して、極低窒素鋼を製造することを目的として種々
検討した結果、既脱酸出鋼時にＣ０２ガスを出鋼領域に
導入した場合に溶鋼の窒素ビックアップ防止に顕著な効
果があることを見出した。なお、導入ガスとしてアルゴ
ンガスについても検討したが、アルゴンガスのみを単独
で置換ガスとして導入しても、溶鋼の窒素ビックアップ
を有効に防止することができないことがわかった。[Means for Solving the Problems] The inventors have developed and put into practical use a so-called non-oxidized steel tapping device that taps steel in a state where the area from the tapping port to the ladle is shielded from the atmosphere. It has been successful in preventing oxidation of molten steel. Therefore, as a result of various studies aimed at producing ultra-low nitrogen steel using this non-oxidized steel tapping equipment, the inventors found that when C02 gas is introduced into the tapping area during deoxidized steel tapping. It was found that this method has a remarkable effect on preventing nitrogen surprise in molten steel. Although argon gas was also considered as an introduced gas, it was found that even if argon gas alone was introduced as a replacement gas, nitrogen surprise in the molten steel could not be effectively prevented.
この発明に係る清浄鋼の製造方法は、転炉−内に脱酸剤
を添加して溶鋼及び溶融酸化物を還元する脱酸工程と、
ＣＯ２ガスを主成分とし、かつ、窒素戊分を含まない置
換ガスを、転炉出鋼口から受鋼容器に至るまでの出ｆｖ
４ｗ４域に導入して、置換ガスで出鋼領域を置換するガ
ス置換工程と、転炉から受鋼容器に溶鋼を出鋼する出鋼
工程と、を有することを特徴とする。The method for producing clean steel according to the present invention includes a deoxidizing step of adding a deoxidizing agent into a converter to reduce molten steel and molten oxides;
The replacement gas, which is mainly composed of CO2 gas and does not contain nitrogen, is supplied from the converter tap to the steel receiving vessel.
It is characterized by having a gas replacement step in which the steel is introduced into the 4w4 region and the tapping region is replaced with a replacement gas, and a tapping step in which molten steel is tapped from a converter into a steel receiving container.
この場合に、置換ガスが、９ｏ容積％以上のＣＯ２ガス
を含む組成であることが好ましく、これに少量の酸素ガ
スをｄ人してもよい。In this case, the replacement gas preferably has a composition containing 90% by volume or more of CO2 gas, and a small amount of oxygen gas may be added thereto.
〔作用］
未脱酸出鋼を採用する理由は、出鋼時に溶鋼を脱酸（既
脱酸出鋼）して溶鋼中溶存［０］を低下させると、溶鋼
が大気中の窒素ガスを吸収しゃすくなるからである。す
なわち、既脱酸出鋼は、出鋼溶鋼が窒素ピックアップを
生じる結果、［Ｎ］量が数ｐ１）１〜１ ０ ｐｐｍ程
度の極低窒素鋼を溶製する場合に不利となる。また、既
脱酸出鋼すると、スラグ・メタル間における複燐反応が
促進し、溶鋼中［Ｐ］ｆｆｉが増えて、極低燐鋼を溶製
する場合にも不利になる。[Effect] The reason why undeoxidized tapped steel is used is that when the molten steel is deoxidized during tapping (deoxidized tapped steel) to lower the dissolved [0] in the molten steel, the molten steel absorbs nitrogen gas in the atmosphere. This is because it becomes uncomfortable. That is, deoxidized tapped steel is disadvantageous when producing extremely low nitrogen steel with a [N] amount of about several p1) 1 to 10 ppm, as a result of nitrogen pickup occurring in the tapped molten steel. In addition, when deoxidized steel is tapped, the double phosphorus reaction between slag and metal is promoted, and [P]ffi in the molten steel increases, which is also disadvantageous when producing ultra-low phosphorus steel.
この発明に係る清浄鋼の製造方法においては、吹錬末期
にＡ，９，Ｓｉ等の脱酸剤を転炉内に投入して、溶鋼を
脱酸すると共に、スラグ中のクロム酸化物やマンガン酸
化物を還元し、これらの有用成分を溶鋼に戻す。次いで
、この既脱酸溶鋼を、ＣＯ２ガス雰囲気下の取鍋内に出
鋼する。Ｃｏ２ガスは、弱酸化性のガスであるため、溶
鋼中溶存〔０］が低下したときに溶鋼の窒素ビックアッ
プを有効に防ぐ役割を有する。すなわち、転炉炉内の溶
鋼に脱酸剤を添加して脱酸し、溶鋼中溶存［０］を低下
させた場合に、ＣＯ２ガスが溶鋼の周囲に存在するので
、［Ｎ］が上昇し難い雰囲気となっている。このため、
出鋼時に窒素ビックアップを受けることなく、溶鋼のＴ
ｏｔａｌ［０］が低減される。In the method for manufacturing clean steel according to the present invention, a deoxidizing agent such as A, 9, Si, etc. is introduced into the converter at the final stage of blowing to deoxidize the molten steel and remove chromium oxides and manganese from the slag. Oxides are reduced and these useful components are returned to the molten steel. Next, this deoxidized molten steel is tapped into a ladle under a CO2 gas atmosphere. Since Co2 gas is a weakly oxidizing gas, it has the role of effectively preventing nitrogen surprise in molten steel when dissolved [0] in molten steel decreases. In other words, when a deoxidizing agent is added to the molten steel in the converter furnace to deoxidize it and reduce the [0] dissolved in the molten steel, [N] increases because CO2 gas is present around the molten steel. The atmosphere is difficult. For this reason,
T of molten steel without nitrogen surprise during tapping.
otal[0] is reduced.
［実施例］
以下、添付の図面を参照して、この発明の実施例につい
て具体的に説明する。[Embodiments] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
第１図は、出鋼時における転炉および取鍋を模式的に示
す断面図である。転炉２は、無酸化出鋼装置および添加
物投入装置を有するものであり、図示ｌ５ないトラニオ
ンリングを介して図示しない傾動装置により回動可能に
支持されている。添加物投入装置は、複数のホッパおよ
び秤量器を備えテイる。ホッパのうちの１つには、粉末
又は粒状の金属アルミニウムが貯蔵されている。FIG. 1 is a sectional view schematically showing a converter and a ladle during tapping. The converter 2 has a non-oxidized steel tapping device and an additive charging device, and is rotatably supported by a tilting device (not shown) via a trunnion ring (not shown). The additive charging device includes a plurality of hoppers and a weighing device. One of the hoppers stores metallic aluminum in powder or granular form.
軌条が建屋外から転炉２の前面を通過するように敷設さ
れ、台車が軌条に沿って走行可能に設けられている。空
の状態の取鍋６が台車に搭載され、蓋７が被せられてい
る。A rail is laid so as to pass in front of the converter 2 from outside the building, and a truck is provided so as to be able to run along the rail. An empty ladle 6 is mounted on a truck and covered with a lid 7.
出鋼口５が転炉２の上部側壁の前面側に設けら打ている
。出鋼口５の開口には開閉装置の部材（図示せず）が嵌
まり込むようになっている。この開閉部材はガス吹き込
み装置を有しており、出鋼時に溶鋼にガスを吹き付ける
ようになっている。A tapping port 5 is provided on the front side of the upper side wall of the converter 2. A member of a switchgear (not shown) is fitted into the opening of the tapping port 5. This opening/closing member has a gas blowing device, which blows gas onto the molten steel during tapping.
蓋７が取鍋６に披せられ、取鍋６内が密閉されるように
なっている。Ｍ７の中央部は突出し、突出部７ａの上端
部が転炉傾動時に出鋼口５に連通される高さα置に達し
ている。A lid 7 is placed over the ladle 6, so that the inside of the ladle 6 is sealed. The central portion of M7 protrudes, and the upper end of the protruding portion 7a reaches a height α at which it communicates with the tapping port 5 when the converter is tilted.
ガス管８．９が、それぞれ蓋７の適所に設けられている
。各ガス管８，９は、流量調整弁を有するＣ Ｏ ２ガ
ス供給ｇ（図示せず）に連通されている。Gas pipes 8.9 are each provided in place on the lid 7. Each gas pipe 8, 9 is connected to a CO2 gas supply g (not shown) having a flow rate regulating valve.
に連通している。is connected to.
第２図は、この発明の実施例に係る清浄鋼の製造方法を
示す工程図である。この第２図を参照しながら、極低窒
素鋼を溶製する場合について説明する。FIG. 2 is a process diagram showing a method for manufacturing clean steel according to an embodiment of the present invention. With reference to FIG. 2, the case of producing ultra-low nitrogen steel will be described.
吹錬末期に至ると、所定量の脱酸剤を転炉内に投入して
、溶鋼３を脱酸する（工程２０）。脱酸剤に金属アルミ
ニウムを用いる場合は、溶鋼１トン当たりの投入量を約
２ｋｇとする。これにより、溶鋼３の溶存［０１量が５
ｐｐａ＋以下に低威されると共に、転炉スラグ４の中
の酸化鉄、酸化クロム並びに酸化マンガンが還元される
。スラグ中のＦｅＣｒ，Ｍｎ等の有用成分が還元されて
溶鋼３に戻されると、スラグ４の（Ｔ−Ｆｅ）が低下し
、濱鋼３の再酸化が生じ難くなる。この結果、鍋内に流
出した転炉スラグが、鋳造工程まで持ち込まれたとして
も、これと溶鋼３との反応により生じるＡＲ２０３及び
Ｓｉ０２の生戊量が大幅に低減され、鋳片表面性状が向
上する。When the final stage of blowing is reached, a predetermined amount of deoxidizer is introduced into the converter to deoxidize the molten steel 3 (step 20). When metallic aluminum is used as a deoxidizing agent, the amount to be added per ton of molten steel is approximately 2 kg. As a result, the amount of dissolved [01] of molten steel 3 is 5
The iron oxide, chromium oxide, and manganese oxide in the converter slag 4 are reduced to less than ppa+. When useful components such as FeCr and Mn in the slag are reduced and returned to the molten steel 3, the (T-Fe) of the slag 4 decreases, making it difficult for the steel 3 to reoxidize. As a result, even if the converter slag that has flowed into the ladle is brought into the casting process, the amount of AR203 and Si02 produced by the reaction between it and the molten steel 3 is significantly reduced, and the surface quality of the slab is improved. do.
取鍋６を、空の状態で転炉２の前方所定位置に配置し、
蓋７を被せる。蓋７には、ガス管８．９の先端部分が予
め取り付けられてあり、これらに継手を用いてそれぞれ
の基端部分を接続する。Place the ladle 6 in an empty state at a predetermined position in front of the converter 2,
Cover with lid 7. The distal end portions of gas pipes 8.9 are attached in advance to the lid 7, and the base end portions of the gas pipes 8.9 are connected to these using joints.
ガス管８，９を介して取鍋６内にＣ Ｏ ２ガスを導入
し、取鍋６内をガス置換する（工程２１）。この場合に
、ガス流量を毎時５０００〜１００００Ｎｍ３とし、ガ
ス置換時間を約５分間とする。C O 2 gas is introduced into the ladle 6 via the gas pipes 8 and 9 to replace the inside of the ladle 6 with gas (step 21). In this case, the gas flow rate is set to 5000 to 10000 Nm3 per hour, and the gas replacement time is set to about 5 minutes.
吹錬が終了すると、転炉２を取鍋６の側に傾動させ、出
鋼口５を蓋の突出部７ａ上端に整合させる。開閉部材を
出鋼口５の溶鋼通流口から離脱させ、出鋼を開始する（
工程２２）。このとき、取鍋６内がＣＯ２ガスで満たさ
れた雰囲気にあるので、大気から溶鋼が遮断され、溶鋼
の窒素ビックアップが防止される。なお、出鋼時におけ
る溶鋼の溶存［Ｏ］は約１ 〜５ １）Ｉｌｌｆｆ、［
Ｎコは約１５ｐｐ＋ｗである。When the blowing is completed, the converter 2 is tilted toward the ladle 6, and the tapping port 5 is aligned with the upper end of the protrusion 7a of the lid. Remove the opening/closing member from the molten steel flow port of the tapping port 5 and start tapping (
Step 22). At this time, since the inside of the ladle 6 is in an atmosphere filled with CO2 gas, the molten steel is blocked from the atmosphere, and nitrogen surprise of the molten steel is prevented. In addition, the dissolved [O] of molten steel during tapping is approximately 1 to 5. 1) Illff, [
N is approximately 15pp+w.
出鋼停止後、置換ガスの供給を停止し、ガス管８．９の
継手をそれぞれ解除する。次いて、蓋７を開け、取鍋６
内に流出した転炉スラグを除去する。この場合に、既脱
酸出鋼しているため、スラグ中の（Ｆ ｅＯ）， （
Ｆ ｅ２ ０３ ）． （ＭｎＯ）の一部は還元され
ており、スラグの存在は必ずしも溶鋼再酸化を起こすほ
ど有害てはない。従って、除滓作業を省略または簡略化
することも可能である。After stopping the tapping, the supply of replacement gas is stopped and the joints of the gas pipes 8 and 9 are released. Next, open the lid 7 and ladle 6.
Remove the converter slag that has flowed into the tank. In this case, since the steel has already been deoxidized, (FeO) in the slag, (
F e2 03 ). Some of the (MnO) has been reduced, and the presence of slag is not necessarily harmful enough to cause re-oxidation of the molten steel. Therefore, it is also possible to omit or simplify the slag removal work.
この後、必要であれば、取鍋内に保瓜材を投入して湯而
を覆い、溶鋼の保温および酸化防止を図る。After that, if necessary, a melon insulator is put into the ladle to cover the hot water to keep the molten steel warm and prevent it from oxidizing.
鍋を連続鋳造設備に搬送し、鍋内の溶鋼をタンディッシ
ュを介して鋳型に連続鋳造する（工程２３）。The pot is transported to continuous casting equipment, and the molten steel in the pot is continuously cast into a mold via a tundish (step 23).
上記実施例によれば、窒素ピックアップを実質的に生じ
ることなく、［Ｎ］４２が３ ０ ｐｐｍ以下で、かつ
、Ｔｏｔａｌ ［０］ 量が２ ０ ｐｐｍ以下の鋳造
溶鋼を得ることができた。既脱酸出鋼を採用することが
できるので、ＲＨ脱ガス処理が不要となる。According to the above examples, it was possible to obtain cast molten steel in which [N]42 was 30 ppm or less and the total [0] amount was 20 ppm or less without substantially generating nitrogen pickup. Since already deoxidized steel can be used, RH degassing treatment is not necessary.
なお、上記実施例では、低窒素鋼を溶製する場合につい
て説明したが、これに限られることなく、低窒素ｌ農度
のステンレス鋼、９％Ｎｉ鋼、高マンガン鋼等をそれぞ
れ溶製することもできる。In addition, in the above embodiment, the case where low nitrogen steel is melted is explained, but the present invention is not limited to this, and low nitrogen content stainless steel, 9% Ni steel, high manganese steel, etc. can be melted. You can also do that.
［発明の効果ゴ
本発明によれば、転炉に備えられた無酸化出鋼装置を利
用することにより、窒素ビックアップを生じることなく
、既脱酸出鋼することができる。[Effects of the Invention] According to the present invention, deoxidized steel can be tapped without causing nitrogen surprise by using a non-oxidized steel tapping device provided in a converter.
このため、転炉出鋼工程で［Ｎ］ ｆｆｉを上昇させる
ことなく、溶存［０］ ｍを大幅に低減することができ
るので、低窒素鋼を低コストかつ容易に製造することが
できる。特に、ＲＨ脱ガス処理等の二次精錬における処
理負担を低減することができ、溶鋼中Ｔｏｔａｌ［０］
が２ ０ ｐｐｍ以下の清浄鋼を安価かつ容易に製造す
ることができる。Therefore, dissolved [0] m can be significantly reduced without increasing [N] ffi in the converter tapping process, so that low-nitrogen steel can be manufactured easily at low cost. In particular, it is possible to reduce the processing burden in secondary refining such as RH degassing treatment, and the total [0]
It is possible to produce clean steel with a carbon content of 20 ppm or less at low cost and easily.
また、転炉スラグ中の酸化クロムおよび酸化マンガンが
脱酸剤により還元され、これらの有効成分が溶鋼に戻さ
れるので、溶鋼の歩留りを向上することができる。更に
、転炉スラグが鋳造工程まで持ち込まれたとしても、ス
ラグ・メタル反応によるアルミナおよびシリカの生成量
が大幅に制限され、鋳造溶鋼の清浄度が維持される。Further, the chromium oxide and manganese oxide in the converter slag are reduced by the deoxidizing agent, and these effective components are returned to the molten steel, so the yield of the molten steel can be improved. Furthermore, even if the converter slag is carried into the casting process, the amount of alumina and silica produced by the slag-metal reaction is significantly limited, and the cleanliness of the cast molten steel is maintained.
また、従来の未脱酸出鋼においては、出鋼直後の除滓作
業が必須であり、出鋼から取Ｎ４搬出に至るまでの一連
の作業に多大の労力を要していたが、既脱酸出鋼を採用
することによりこれを省略または簡略化することができ
る。In addition, in conventional undeoxidized tapped steel, it was necessary to remove the slag immediately after tapping, and the series of operations from tapping to removing N4 required a lot of effort. This can be omitted or simplified by adopting oxidized steel.
第１図は出鋼時の転炉および取鍋を漢式的に示す縦断面
図、第２図は本発明の実施例に係る清浄鋼の製造方法を
説明するための工程図である。FIG. 1 is a longitudinal sectional view showing a converter and a ladle in Chinese style during tapping, and FIG. 2 is a process diagram for explaining the method for manufacturing clean steel according to an embodiment of the present invention.
Claims (1)
る脱酸工程と、ＣＯ＿２ガスを主成分とし、かつ、窒素
成分を含まない置換ガスを、転炉出鋼口から受鋼容器に
至るまでの出鋼領域に導入して、置換ガスで出鋼領域を
置換するガス置換工程と、転炉から受鋼容器に溶鋼を出
鋼する出鋼工程と、を有することを特徴とする清浄鋼の
製造方法。A deoxidizing process in which a deoxidizing agent is added into the converter to reduce molten steel and molten oxides, and a replacement gas containing CO_2 gas as the main component and containing no nitrogen components is used to receive steel from the tap port of the converter. It is characterized by having a gas replacement step in which the gas is introduced into the tapping region up to the container and replaces the tapping region with a replacement gas, and a tapping step in which molten steel is tapped from the converter into the steel receiving container. A method for producing clean steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15019589A JPH0317216A (en) | 1989-06-13 | 1989-06-13 | Production of clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15019589A JPH0317216A (en) | 1989-06-13 | 1989-06-13 | Production of clean steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0317216A true JPH0317216A (en) | 1991-01-25 |
Family
ID=15491595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15019589A Pending JPH0317216A (en) | 1989-06-13 | 1989-06-13 | Production of clean steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0317216A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012207272A (en) * | 2011-03-30 | 2012-10-25 | Nisshin Steel Co Ltd | Method for preventing nitrogen absorption when smelting stainless steel |
| JP2016132808A (en) * | 2015-01-20 | 2016-07-25 | 新日鐵住金株式会社 | Method for melting low nitrogen steel |
| CN108285947A (en) * | 2017-02-28 | 2018-07-17 | 安徽工业大学 | A kind of molten steel alloyage process in protection tapping process |
-
1989
- 1989-06-13 JP JP15019589A patent/JPH0317216A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012207272A (en) * | 2011-03-30 | 2012-10-25 | Nisshin Steel Co Ltd | Method for preventing nitrogen absorption when smelting stainless steel |
| JP2016132808A (en) * | 2015-01-20 | 2016-07-25 | 新日鐵住金株式会社 | Method for melting low nitrogen steel |
| CN108285947A (en) * | 2017-02-28 | 2018-07-17 | 安徽工业大学 | A kind of molten steel alloyage process in protection tapping process |
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