JPH08928B2 - Refining method for high N stainless steel - Google Patents
Refining method for high N stainless steelInfo
- Publication number
- JPH08928B2 JPH08928B2 JP63242417A JP24241788A JPH08928B2 JP H08928 B2 JPH08928 B2 JP H08928B2 JP 63242417 A JP63242417 A JP 63242417A JP 24241788 A JP24241788 A JP 24241788A JP H08928 B2 JPH08928 B2 JP H08928B2
- Authority
- JP
- Japan
- Prior art keywords
- concentration
- blowing
- gas
- stainless steel
- degassing
- 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
- 238000000034 method Methods 0.000 title claims description 16
- 239000010935 stainless steel Substances 0.000 title claims description 13
- 229910001220 stainless steel Inorganic materials 0.000 title claims description 13
- 238000007670 refining Methods 0.000 title claims description 12
- 238000007664 blowing Methods 0.000 claims description 25
- 229910000831 Steel Inorganic materials 0.000 claims description 20
- 239000007789 gas Substances 0.000 claims description 20
- 239000010959 steel Substances 0.000 claims description 20
- 238000007872 degassing Methods 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 238000007865 diluting Methods 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、ステンレス鋼の精錬方法、特に窒素濃度の
比較的高いステンレス鋼の安価な製造方法に関するもの
である。TECHNICAL FIELD The present invention relates to a method for refining stainless steel, and particularly to an inexpensive method for producing stainless steel having a relatively high nitrogen concentration.
〈従来の技術〉 ステンレス鋼の精錬プロセスとして次のようなプロセ
スが一般的に知られている。<Prior Art> The following processes are generally known as refining processes for stainless steel.
なかでも，，の真空精錬装置を用いるプロセス
では溶鋼中の〔Ｎ〕は比較的容易に除去されるので、目
標の〔Ｎ〕濃度が比較的高い場合には、Ｎ含有合金を
添加する，大気下で所定量のN2ガスを吹込む，鋳造
工程で注入流にN2ガスを吹きつけたり吹込むなどの方法
がとられ、さらに特殊な例として、真空誘導炉を用い
た特開昭59-96210号公報に開示されているような窒素添
加方法がある。 Among them, in the process using the vacuum refining device of, since [N] in the molten steel is relatively easily removed, when the target [N] concentration is relatively high, the N-containing alloy is added to the atmosphere. A predetermined amount of N 2 gas may be blown below, or N 2 gas may be blown or blown into the injection flow in the casting process, and as a more specific example, a vacuum induction furnace is used. There is a nitrogen addition method as disclosed in Japanese Patent Publication No. 96210.
〈発明が解決しようとする課題〉 しかし、前記の技術にはそれぞれつぎのような問題が
ある。<Problems to be Solved by the Invention> However, each of the above techniques has the following problems.
Ｎ含有合金を添加する場合は他の合金成分が必要以
上に増加し、またＮ含有合金は高価なためコストアップ
となる。When the N-containing alloy is added, other alloy components increase more than necessary, and the N-containing alloy is expensive, resulting in cost increase.
大気下でN2ガスを吹込む場合には、工程が１工程増
えるために処理時間が延び耐火物溶損の増加や生産性の
低下となる。When N 2 gas is blown in the atmosphere, the process time is increased because the number of processes is increased by one, resulting in an increase in melting loss of refractory and a decrease in productivity.
鋳造中に注入流にN2ガスを吹き付けたり吹込んだり
する方法は、Ｎ添加量に応じたN2分圧や接触時間のコン
トロールが困難で製品〔Ｎ〕濃度が鋳片毎に、或いは溶
製単位毎に大きく変動する。In the method of blowing N 2 gas into the injection flow during casting, it is difficult to control the N 2 partial pressure and contact time according to the N addition amount, and the product [N] concentration is different for each cast piece or melted. It varies greatly from manufacturing unit to manufacturing unit.
真空誘導炉では大量生産に適さない。 Vacuum induction furnace is not suitable for mass production.
本発明は、従来技術の前述のような問題に鑑み、溶解
脱炭・還元精錬炉として使用される底吹，横吹または上
底吹転炉の酸素の希釈ガス，溶鉄，溶鋼の撹拌ガスとし
て用いられる高価なArガスに代えて安価なN2ガスを最大
限に使用し、しかも脱ガスプロセスで所望の〔Ｎ〕濃度
をバラツキ少なく得ることのできる高〔Ｎ〕ステンレス
鋼の精錬方法を提供するためになされたものである。In view of the above-mentioned problems of the prior art, the present invention is used as a diluting gas for oxygen, molten iron, and a stirring gas for molten steel in a bottom blowing, side blowing or top blowing converter used as a melting decarburizing / reducing smelting furnace. Disclosed is a refining method for high [N] stainless steel, which can maximize the use of inexpensive N 2 gas instead of the expensive Ar gas used and can obtain a desired [N] concentration with little variation in the degassing process. It was done for good.
〈課題を解決するための手段〉 本発明は、底吹，横吹または上底吹転炉と脱ガスプロ
セスとを用いる高Ｎステンレス鋼の精錬方法において、
溶解脱炭・還元精錬炉として使用される底吹，横吹また
は上底吹転炉の酸素希釈ガス、溶鉄・溶鋼の撹拌ガスと
してN2ガスを吹き込んで、ステンレス溶鋼中〔Ｎ〕濃度
が目標〔Ｎ〕濃度以上となるように加窒し、次に脱ガス
槽内N2分圧をコントロールして目標〔Ｎ〕濃度となるま
で脱窒することを特徴とする高Ｎステンレス鋼の精錬方
法である。<Means for Solving the Problems> The present invention provides a refining method for high N stainless steel using a bottom blowing, side blowing or top bottom blowing converter and a degassing process.
The bottom [blown], side [blown] or top / bottom blow converter used as a melting and decarburizing / reduction smelting furnace, and N 2 gas as a stirring gas for molten iron / molten steel are blown into the molten steel to achieve the target [N] concentration [N]. N] concentration, and then denitrification until the target [N] concentration is reached by controlling the N 2 partial pressure in the degassing tank. is there.
〈作用〉 ステンレス溶鋼の〔％Ｎ〕ｅ、すなわち平衡〔Ｎ〕濃
度は、下記（１）で示されることが一般に知られてい
る。<Operation> It is generally known that the [% N] e, that is, the equilibrium [N] concentration of molten stainless steel is represented by the following (1).
記 log〔％Ｎ〕ｅ＝−188/T−1.25−〔（3280/T−0.075）
（0.13〔％Ｃ〕＋0.047〔％Si〕＋0.01〔％Ni〕−0.01
〔％Mo〕−0.023〔％Mn〕−0.045〔％Cr〕）〕＋1/2 logPN2 ……（１） ここで T:溶鋼温度（Ｋ）， 〔％ｉ〕:i成分の濃度（重量％）， PN2:N2分圧（atm）， したがって、溶鋼温度が一定であればN2分圧によって
平衡〔Ｎ〕濃度はある一定の値となる。また底吹，横吹
または上底吹転炉を用いたステンレス鋼の溶解・脱炭精
錬時には底吹ガスとしてN2を使用することにより、N2分
圧が大気中であることから容易に溶銑・溶鋼中の〔Ｎ〕
濃度を高くすることができる。したがって、底吹，横吹
または上底吹転炉と脱ガスプロセスとを組合せたステン
レス鋼精錬プロセスにおいては、脱ガス処理が可能な0.
1Torr〜200TorrのN2分圧範囲で容易に溶鋼〔Ｎ〕濃度を
コントロールすることができる。Note log [% N] e = -188 / T-1.25-[(3280 / T-0.075)
(0.13 [% C] +0.047 [% Si] +0.01 [% Ni] -0.01
[% Mo] -0.023 [% Mn] -0.045 [% Cr])] + 1/2 logP N2 (1) where T: molten steel temperature (K), [% i]: concentration of i component (% by weight) ), P N2 : N 2 partial pressure (atm), therefore, if the molten steel temperature is constant, the equilibrium [N] concentration becomes a certain value by the N 2 partial pressure. Also, when N 2 is used as the bottom blowing gas during the melting and decarburizing refining of stainless steel using a bottom blowing, side blowing or top bottom blowing converter, the N 2 partial pressure is in the atmosphere, so it is easy to [N] in molten steel
The concentration can be increased. Therefore, in a stainless steel refining process that combines a bottom blowing, side blowing or top bottom blowing converter and a degassing process, degassing treatment is possible.
The molten steel [N] concentration can be easily controlled in the N 2 partial pressure range of 1 Torr to 200 Torr.
〈実施例〉 目標〔Ｎ〕濃度が1000ppmである17Cr-7Ni鋼の平衡
〔Ｎ〕濃度と脱ガス処理時のN2分圧の関係を第１図に示
したが、大気圧下でN2ガスを吹込み約2000ppmの〔Ｎ〕
濃度とした後、脱ガス槽のN2分圧を0.2atm（150Torr）
とすることで約1000ppmの〔Ｎ〕濃度に適中させること
が可能である。Showed the relation <Example> target [N] concentration equilibrium 17Cr-7Ni steel is 1000ppm (N) concentration and degassed when N 2 partial pressure in the first FIG., N 2 at atmospheric pressure Inject gas to about 2000ppm [N]
After setting the concentration, the N 2 partial pressure in the degassing tank is 0.2 atm (150 Torr)
With this, it is possible to properly adjust the [N] concentration to about 1000 ppm.
以下にさらに具体的実施例を説明する。 A more specific example will be described below.
17Cr-7Ni鋼｛目標成分、C/0.025重量％（以下％と略
す）,Si/0.6％,Mn/1.2％,Cr/17.2％,Ni/7.1％｝を上底
吹転炉にてN2ガスを用いて希釈脱炭と還元精錬を行い、
〔Ｎ〕含有量を約2000ppmとした溶鋼をRH脱ガス処理を
行った。処理開始温度は1600℃，処理時間25分でその間
に脱Ｎおよび他成分の微調整を行い1550℃で脱ガス処理
を終了した。この時エゼクター操作で槽内吹込みN2ガス
流量を調節してRH槽内のN2分圧を10Torr（0.013atm）か
ら200Torr（0.263atm）の間で変化させた場合の処理終
了の溶鋼〔Ｎ〕濃度とPN2との関係を第２図に示した。
処理25分後の〔Ｎ〕濃度（●印）は、前述の（１）式に
よる平衡計算値とよく一致していて、脱ガス槽内のN2分
圧調整によって目標〔Ｎ〕濃度の溶鋼が得られることが
明らかである。17Cr-7Ni steel {target composition, C / 0.025% by weight (hereinafter abbreviated as%), Si / 0.6%, Mn / 1.2%, Cr / 17.2%, Ni / 7.1%} N 2 in the top-bottom converter Dilute decarburization and reduction refining using gas,
Molten steel having an [N] content of about 2000 ppm was subjected to RH degassing. The treatment start temperature was 1600 ° C, and the treatment time was 25 minutes, during which degassing and fine adjustment of other components were performed, and the degassing treatment was completed at 1550 ° C. At this time, the molten steel at the end of treatment when the N 2 gas flow rate blown into the tank was adjusted by the ejector operation to change the N 2 partial pressure in the RH tank from 10 Torr (0.013 atm) to 200 Torr (0.263 atm) The relationship between [N] concentration and P N2 is shown in FIG.
The [N] concentration 25 minutes after the treatment (●) is in good agreement with the equilibrium calculated value according to the above equation (1), and the molten steel of the target [N] concentration is adjusted by adjusting the N 2 partial pressure in the degassing tank. It is clear that
また、同じ組成の17Cr-7Ni鋼の目標〔Ｎ〕濃度を900p
pmとし、N2分圧を180Torrとして処理する実験の結果を
第３図に示した。目標〔Ｎ〕濃度が900ppmと比較的高く
てもＮ含有合金の添加、あるいは大気圧下でのN2ガス吹
込なしで容易に溶鋼中の〔Ｎ〕濃度のコントロールが可
能であった。Also, the target [N] concentration of 17Cr-7Ni steel of the same composition is 900p
Fig. 3 shows the result of an experiment in which the pressure was set to pm and the N 2 partial pressure was set to 180 Torr. Even if the target [N] concentration was relatively high at 900 ppm, it was possible to easily control the [N] concentration in the molten steel without adding N-containing alloy or blowing N 2 gas under atmospheric pressure.
〈発明の効果〉 本発明により、ステンレス鋼の〔Ｎ〕濃度コントロー
ルが、底吹，横吹または上底吹転炉と脱ガスプロセスを
用いて、精度よく容易に且つ経済的に行えるようになっ
た。<Effects of the Invention> According to the present invention, the [N] concentration of stainless steel can be controlled accurately, easily and economically by using a bottom blowing, side blowing or top bottom blowing converter and a degassing process. .
すなわち、従来は高〔Ｎ〕ステンレス鋼の溶製が、Ｎ
含有合金の添加、脱ガス処理終了後注入流へのN2ガス吹
込、または大気圧下でのN2ガス吹込というプロセスでし
か溶製しえなかったのに対し、本発明によると脱ガス処
理のみで精度よく経済的に行えるようになった。That is, in the past, the melting of high [N] stainless steel was
Addition of containing alloys, N 2 gas purging or contrast could not have smelted only a process called N 2 gas blowing at atmospheric pressure, degassing According to the present invention, to the degassing process is completed after injection stream Only now can be done accurately and economically.
第１図は、17Cr-7Ni鋼の1550℃における平衡〔Ｎ〕と脱
ガス時PN2との関係を示す特性図、第２図は、本発明に
より溶製した17Cr-7Ni鋼の〔Ｎ〕濃度とPN2との関係を
示す特性図、第３図は、本発明により溶製した17Cr-7Ni
鋼RH脱ガス開始時と終了時の〔Ｎ〕濃度を示す特性図で
ある。FIG. 1 is a characteristic diagram showing the relationship between the equilibrium [N] of 17Cr-7Ni steel at 1550 ° C. and P N2 during degassing, and FIG. 2 is the [N] of 17Cr-7Ni steel melted according to the present invention. Fig. 3 is a characteristic diagram showing the relationship between the concentration and P N2 . Fig. 3 shows the 17Cr-7Ni produced by the present invention.
It is a characteristic view which shows [N] density at the time of steel RH degassing start and end.
Claims (1)
セスとを用いる高Ｎステンレス鋼の精錬方法において、 溶解脱炭・還元精錬炉として使用される底吹，横吹また
は上底吹転炉の酸素希釈ガス、溶鉄・溶鋼の撹拌ガスと
してN2ガスを吹き込んで、ステンレス溶鋼中〔Ｎ〕濃度
が目標〔Ｎ〕濃度以上となるように加窒し、次に脱ガス
槽内N2分圧をコントロールして目標〔Ｎ〕濃度となるま
で脱窒することを特徴とする高Ｎステンレス鋼の精錬方
法。1. A method for refining high N stainless steel using a bottom blowing, side blowing or top blowing converter and a degassing process, wherein bottom blowing, side blowing or top blowing used as a melting decarburizing / reducing refining furnace. N 2 gas is blown in as oxygen diluting gas for the converter and as stirring gas for molten iron and molten steel, and nitrogen is added so that the [N] concentration in the stainless molten steel becomes the target [N] concentration or higher, and then N in the degassing tank. A refining method for high-N stainless steel, which comprises denitrifying until a target [N] concentration is achieved by controlling a partial pressure of 2 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63242417A JPH08928B2 (en) | 1988-09-29 | 1988-09-29 | Refining method for high N stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63242417A JPH08928B2 (en) | 1988-09-29 | 1988-09-29 | Refining method for high N stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0293016A JPH0293016A (en) | 1990-04-03 |
| JPH08928B2 true JPH08928B2 (en) | 1996-01-10 |
Family
ID=17088811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63242417A Expired - Lifetime JPH08928B2 (en) | 1988-09-29 | 1988-09-29 | Refining method for high N stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08928B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0428814A (en) * | 1990-05-25 | 1992-01-31 | Sumitomo Metal Ind Ltd | Method for adjusting nitrogen concentration in molten steel in vacuum refining |
| JP2795597B2 (en) * | 1993-06-11 | 1998-09-10 | 川崎製鉄株式会社 | Vacuum degassing and decarburization of molten stainless steel |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3754894A (en) * | 1972-04-20 | 1973-08-28 | Joslyn Mfg & Supply Co | Nitrogen control in argon oxygen refining of molten metal |
| JPS5625919A (en) * | 1979-08-09 | 1981-03-12 | Sanyo Tokushu Seikou Kk | Preparation of molten steel with low oxygen and high nitrogen |
| JPS573727A (en) * | 1980-06-11 | 1982-01-09 | Central Glass Co Ltd | Tempering of sheet glass |
| JPS58167708A (en) * | 1982-03-29 | 1983-10-04 | Nippon Kokan Kk <Nkk> | Method of controlling molten steel [N] using a top-bottom blowing converter |
| JPS58197211A (en) * | 1982-05-11 | 1983-11-16 | Nippon Stainless Steel Co Ltd | Production of nitrogen-containing low carbon stainless steel |
| JPS61157617A (en) * | 1984-12-29 | 1986-07-17 | Daido Steel Co Ltd | Method for producing Cr-containing alloy steel |
| JPS6337162A (en) * | 1986-08-01 | 1988-02-17 | Ricoh Co Ltd | Disazo pigment with new crystal structure |
-
1988
- 1988-09-29 JP JP63242417A patent/JPH08928B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0293016A (en) | 1990-04-03 |
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