JPH03291323A - Production of clean steel excellent in hydrogen induced cracking resistance - Google Patents
Production of clean steel excellent in hydrogen induced cracking resistanceInfo
- Publication number
- JPH03291323A JPH03291323A JP9368590A JP9368590A JPH03291323A JP H03291323 A JPH03291323 A JP H03291323A JP 9368590 A JP9368590 A JP 9368590A JP 9368590 A JP9368590 A JP 9368590A JP H03291323 A JPH03291323 A JP H03291323A
- Authority
- JP
- Japan
- Prior art keywords
- desulfurization
- molten steel
- steel
- inclusions
- alloy powder
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 69
- 239000010959 steel Substances 0.000 title claims abstract description 69
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 13
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 13
- 239000001257 hydrogen Substances 0.000 title claims abstract description 13
- 238000005336 cracking Methods 0.000 title claims abstract description 12
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000000843 powder Substances 0.000 claims abstract description 39
- 229910000882 Ca alloy Inorganic materials 0.000 claims abstract description 38
- 230000004907 flux Effects 0.000 claims abstract description 19
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 12
- 239000011593 sulfur Substances 0.000 claims abstract description 11
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 9
- 230000003009 desulfurizing effect Effects 0.000 claims description 3
- 230000001737 promoting effect Effects 0.000 claims description 2
- 238000005339 levitation Methods 0.000 claims 1
- 125000000101 thioether group Chemical group 0.000 claims 1
- 238000006477 desulfuration reaction Methods 0.000 abstract description 38
- 230000023556 desulfurization Effects 0.000 abstract description 38
- 238000000034 method Methods 0.000 abstract description 32
- 238000007664 blowing Methods 0.000 abstract description 15
- 238000005188 flotation Methods 0.000 abstract description 5
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 abstract description 4
- 230000003647 oxidation Effects 0.000 abstract 1
- 238000007254 oxidation reaction Methods 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 239000011575 calcium Substances 0.000 description 28
- 239000002893 slag Substances 0.000 description 15
- 229910004709 CaSi Inorganic materials 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 230000003749 cleanliness Effects 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 238000002347 injection Methods 0.000 description 6
- 239000007924 injection Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000007667 floating Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 150000003568 thioethers Chemical class 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 238000005486 sulfidation Methods 0.000 description 4
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000010079 rubber tapping Methods 0.000 description 3
- 229910018107 Ni—Ca Inorganic materials 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009849 vacuum degassing Methods 0.000 description 2
- 239000002966 varnish Substances 0.000 description 2
- 241000473391 Archosargus rhomboidalis Species 0.000 description 1
- 229910014458 Ca-Si Inorganic materials 0.000 description 1
- 101100273027 Dictyostelium discoideum cafA gene Proteins 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000005987 sulfurization reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、例えば硫化水素環境下で使用される耐水素誘
起割れ性の優れた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 with excellent resistance to hydrogen-induced cracking, which is used, for example, in a hydrogen sulfide environment.
（従来の技術）
一般的に、例えば硫化水素環境下において使用される鋼
材（ラインパイプ材等）には、優れた耐水素誘起割れ性
（以下、１耐ＨＩＣ性］ともいう）が要求される。(Prior Art) In general, steel materials (line pipe materials, etc.) used in a hydrogen sulfide environment are generally required to have excellent hydrogen-induced cracking resistance (hereinafter also referred to as 1 HIC resistance). .
ところで、鋼中に存在する硫黄は、その凝固過程で硫化
物としてＭｎＳを生威し、鋳造時にこのＭｎＳが鋳片に
偏析する。このようにして偏析したＭｎＳは、圧延時に
圧延方向に長く伸ばされるため、その後の鋼中への水素
の集積を促進することとなってしまう、その結果、得ら
れる鋼材の前記耐ＨＩＣ性が著しく低下するため、溶銑
段階における予備脱硫に加えて、転炉出鋼後の炉外脱硫
による徹底的な極低硫化が必要である。By the way, sulfur present in steel produces MnS as sulfide during its solidification process, and this MnS segregates into slabs during casting. Since the MnS segregated in this way is elongated in the rolling direction during rolling, it promotes the subsequent accumulation of hydrogen in the steel.As a result, the HIC resistance of the resulting steel material is significantly reduced. Therefore, in addition to preliminary desulfurization at the hot metal stage, it is necessary to thoroughly reduce sulfurization by desulfurization outside the furnace after tapping the steel from the converter.
この炉外脱硫には、様々な方法が考えられており、例え
ば
■脱硫剤を予め取鍋内に入れておき、他の容器から溶鋼
を注入した際にｆ４鋼の衝撃波による混合撹拌作用を利
用して溶鋼と脱硫剤との反応を促進させる取鍋置注ぎ法
、
■例えば、取鍋等の容器に予め偏心回転を与えておき、
その際に生しる特異な波動を反応物質の混合撹拌に利用
する揺動取鍋法、さらには■例えば、Ｃａｂ、Ｃａ○＋
ＣａＦｚ、ＣａＳｉ等の脱硫剤の粉末を気体とともに溶
鋼中に吹き込んで脱硫する脱硫剤吹き込み法
等がある。Various methods have been considered for this out-of-furnace desulfurization, for example: ■ Desulfurization agent is placed in a ladle in advance, and when molten steel is poured from another container, the mixing and stirring effect of the shock wave of F4 steel is used. The ladle pouring method promotes the reaction between the molten steel and the desulfurization agent. ■For example, by giving eccentric rotation to a container such as a ladle in advance,
The rocking ladle method uses the unique waves generated at that time to mix and stir the reactants, and also ■For example, Cab, Ca○+
There is a desulfurization agent injection method in which a powder of a desulfurization agent such as CaFz or CaSi is blown into molten steel together with a gas to desulfurize the steel.
これらの方法のうち、近年では脱硫反応効率および溶鋼
清浄性の観点から脱硫剤吹き込み法が広く用いられてい
る０例えば、前記耐ＨＩＣ性の低下を防止するために、
酸素や硫黄との親和力が大きく、溶鋼中の全酸素量およ
び全硫黄量の低減に有効であるＣａを吹き込んで、硫化
物の形態制御を実施して圧延時に影響を受けないように
して、耐水素誘起割れを防止することが可能な手段が種
々提案されている。Among these methods, the desulfurization agent injection method has been widely used in recent years from the viewpoint of desulfurization reaction efficiency and molten steel cleanliness.
By injecting Ca, which has a high affinity with oxygen and sulfur and is effective in reducing the total amount of oxygen and total sulfur in molten steel, the morphology of sulfides is controlled so that they are not affected during rolling, thereby improving durability. Various means have been proposed to prevent hydrogen-induced cracking.
例えば、脱硫剤としてＣａまたはＣａ合金を用いた硫化
物の形態制御の方法としては、Ｃａ５ｔ粉末単独の吹き
込み法やＣａワイヤーによるＣａ添加法がＨ誌「鉄と鋼
Ｊ （１９８５、Ｖｏ１７１．１２３頁、日本鉄綱協会
）に、またＲＨ真空脱ガス処理装置でのＮｉ −Ｃａ、
Ｃｕ −Ｃａ等のＣａ合金による添加法が雑誌「鉄と鋼
」（１９８４，５９８０、日本鉄綱協会）によりそれぞ
れ報告されている。For example, methods for controlling the morphology of sulfides using Ca or Ca alloy as a desulfurization agent include a method of blowing Ca5t powder alone and a method of adding Ca using a Ca wire. , Japan Iron and Steel Association), and Ni-Ca in RH vacuum degassing treatment equipment.
Addition methods using Ca alloys such as Cu-Ca have been reported in the magazine "Tetsu to Hagane" (1984, 5980, Japan Iron and Steel Association).
また、特公昭５９−２２７６５号公報には、予め脱酸処
理した溶鋼にＣａＯ含有フラックスを吹き込んで、脱酸
脱硫した後、さらにＣａ合金を吹き込んで、溶鋼中の硫
化物の形態を制御することにより、低酸素、低硫黄鋼を
製造する方法が提案されている。Furthermore, Japanese Patent Publication No. 59-22765 discloses that a CaO-containing flux is injected into molten steel that has been deoxidized in advance to perform deoxidation and desulfurization, and then a Ca alloy is further injected to control the form of sulfides in the molten steel. proposed a method for producing low-oxygen, low-sulfur steel.
（発明が解決しようとするＩＩ！り
しかしながら、前述の方法には、以下に示すような欠点
が挙げられる。(II) However, the above-mentioned method has the following drawbacks.
すなわち、Ｃａ５ｔ粉末を単独で吹き込む場合には、脱
硫を充分行うに必要な量の吹き込みを行うと、Ｃａ形態
制御を行うに必要かつ充分な量より過剰な量のＣａが溶
鋼中に存在してしまい、必ずしも溶鋼の清浄度は向上し
ない。逆に、Ｃａ形態制御に最適な吹込量では、充分な
脱硫が得られないという問題がある。In other words, when Ca5t powder is injected alone, if the amount necessary for sufficient desulfurization is injected, an excess amount of Ca will be present in the molten steel than the amount necessary and sufficient to control the Ca form. Therefore, the cleanliness of molten steel does not necessarily improve. On the other hand, there is a problem that sufficient desulfurization cannot be obtained with the optimum injection amount for Ca form control.
また、ＣａワイヤーによるＣａ添加法では、Ｗｔ硫は期
待できないため、Ｃａ添加前に脱硫処理を行うことが必
要となること、また添加時の安全面での問題等が大きな
欠点として挙げられる。Further, in the Ca addition method using a Ca wire, Wt sulfur cannot be expected, so a desulfurization treatment must be performed before adding Ca, and safety problems during addition are major drawbacks.
また、Ｒ１１真空脱ガス処理装置におけるＮｉ −Ｃａ
、Ｃｕ−Ｃａ、 Ｆｅ−Ｃａ合金等のＣａ合金による添
加法では、■Ｎｉ、 Ｃｕを含む特殊な合金鋼以外には
適用できない、
■Ｆｅ−Ｃａ合金の場合、Ｃａ歩留が低いという問題が
ある。In addition, Ni-Ca in R11 vacuum degassing equipment
The addition method using Ca alloys such as , Cu-Ca, and Fe-Ca alloys cannot be applied to anything other than special alloy steels containing Ni and Cu. ■ In the case of Fe-Ca alloys, there is a problem of low Ca yield. be.
さらに、特公昭５９−２２７６５号公報では、Ｃａ合金
には溶鋼の脱酸、脱硫および硫化物形態制御効果があり
、ＣａＯ含有フラックスには脱酸および脱硫効果がある
ことが示されているが、この特公昭５９−２２７６５号
公報により提案された方法は、ＣａＯ含有フラックス吹
込み後にＣａ合金を吹き込むため、結局ＣａＳｉ粉末を
単独で吹き込む場合と同様に、■Ｃａ形態制御を優先す
ると、脱硫効率が向上しない、
■脱硫効率を優先すると、溶鋼清浄性が向上しない、
という問題があり、所望の清浄鋼を得ることはできない
。Furthermore, in Japanese Patent Publication No. 59-22765, it is shown that Ca alloy has the effect of deoxidizing and desulfurizing molten steel and controlling the form of sulfides, and that CaO-containing flux has the effect of deoxidizing and desulfurizing. The method proposed in Japanese Patent Publication No. 59-22765 injects the Ca alloy after injecting the CaO-containing flux, so as with the case where CaSi powder is injected alone, desulfurization efficiency increases if priority is given to controlling the Ca form. ■If priority is given to desulfurization efficiency, the cleanliness of molten steel will not improve.There is a problem that the desired clean steel cannot be obtained.
本発明は、これらの問題点を解消し、効果的な耐水素誘
起割れ性に優れた清浄鋼の製造方法を提供することを目
的としている。The object of the present invention is to solve these problems and provide a method for producing clean steel that is effective and has excellent hydrogen-induced cracking resistance.
（課題を解決するための手段）
前記目的を達成するため、本発明者らは鋭意研突を重ね
た。その結果、以下に述べるような知見を得た。(Means for Solving the Problem) In order to achieve the above object, the present inventors have made extensive efforts. As a result, we obtained the following knowledge.
すなわち、１次精錬により脱酸処理した後の溶鋼に、吹
き込み装置よりＣａ合金粉末、例えばＣａＳｉ粉末を吹
き込んだ後、さらにＣａＯ含有フラックスを吹き込むこ
とにより、ＣａＳｉによる溶鋼の強脱硫とその後のＣａ
Ｏ含有含有ワラスによる介在物の浮上促進とを図ること
ができる。That is, by blowing Ca alloy powder, such as CaSi powder, into molten steel that has been deoxidized by primary refining from a blowing device, and then blowing a CaO-containing flux, strong desulfurization of the molten steel by CaSi and subsequent Ca
It is possible to promote the floating of inclusions due to the O-containing glass.
本発明者らは、このような知見に基づいて、さらに検討
を重ねた結果、本発明を完成するに至った。The present inventors conducted further studies based on such knowledge, and as a result, completed the present invention.
ここに、本発明の要旨とするところは、取鍋内の予め脱
酸処理した？８鋼にＣａ合金粉末を添加することにより
脱酸、脱硫および硫化物形態の制御を行った後、引き続
いて該溶鋼にＣａＯ含有フラックスを添加し、脱硫およ
び介在物の浮上を促進することを特徴とする耐水素誘起
割れ性の優れた清浄鋼の製造方法である。Here, the gist of the present invention is that the inside of the ladle has been deoxidized in advance. 8 steel by adding Ca alloy powder to deoxidize, desulfurize, and control the sulfide morphology, and subsequently add CaO-containing flux to the molten steel to promote desulfurization and floating of inclusions. This is a method for producing clean steel with excellent hydrogen-induced cracking resistance.
本発明において、「耐水素割れ性の優れた」とは、具体
的には、ＮＡＣＥ条件で、ＨＩＣ割れの面積率が０％で
あることをいう。In the present invention, "excellent hydrogen cracking resistance" specifically means that the area ratio of HIC cracking is 0% under NACE conditions.
本発明によれば、前述の従来法で示した問題点はすべて
解決することができ、さらに溶鋼の極低硫化と介在物の
形態制御とを実現することができ、耐ＨＩＣ性の優れた
清浄鋼を確実に製造することが可能となる。According to the present invention, all the problems shown in the conventional methods described above can be solved, and furthermore, it is possible to realize extremely low sulfidation of molten steel and control of the morphology of inclusions, and it is possible to achieve cleanliness with excellent HIC resistance. It becomes possible to reliably manufacture steel.
なお、本発明により最終的に得られる清浄鋼中の酸素含
有量は１５ｐｐ−以下、硫黄含有量は５ ｐｐｍ以下で
ある。Note that the oxygen content in the clean steel finally obtained by the present invention is 15 ppm or less, and the sulfur content is 5 ppm or less.
また、本発明における「硫化物」とはＭｎＳをいい、本
発明においてＣａ合金粉末の添加により、Ｃａが鋼中の
ＡＱｚ（ｈ と反応してカルシウムアルミネートの球状
介在物を生成する。Furthermore, "sulfide" in the present invention refers to MnS, and in the present invention, by adding Ca alloy powder, Ca reacts with AQz(h 2 ) in steel to produce spherical inclusions of calcium aluminate.
（作用〉 以下、本発明の構成および作用効果について詳述する。(effect) Hereinafter, the configuration and effects of the present invention will be explained in detail.
なお、本明細書においては、特にことわりがない限り、
「％Ｊは「重量％」を意味するものとする。In addition, in this specification, unless otherwise specified,
"%J" shall mean "% by weight".
本発明は、略述すれば、溶鋼中へのＣａ添加により耐Ｈ
ＩＣ鯛の極低硫化および介在物形層制御を図るに際し、
まず取鍋内の予め脱酸処理を施しである溶鋼中にＣａ合
金粉末を添加することにより脱酸、脱硫、硫化物の形態
制御、とりわけ強脱硫を行った後、引き続いて該溶鋼に
ＣａＯ含有フラックスを添加することにより脱硫および
介在物の浮上を促進することを特徴とする発明である。Briefly, the present invention provides resistance to H by adding Ca to molten steel.
When aiming for extremely low sulfidation and inclusion layer control for IC sea bream,
First, Ca alloy powder is added to molten steel that has been previously deoxidized in a ladle to perform deoxidation, desulfurization, and control of the form of sulfides, especially strong desulfurization, and then CaO is added to the molten steel. This invention is characterized in that desulfurization and floating of inclusions are promoted by adding flux.
本発明において、溶鋼は転炉出鋼時もしくはＲＨ脱ガス
処理装置において、Ｃａ添加前にＡＱ、 Ｓｔ、 Ｍｎ
等によ−り予め脱酸処理しておく、脱酸の程度は特に限
定を要するものではないが、溶鋼清浄性の観点から、
［ＡＱ］ ” ｔｒａｃｅもしくはそれ以上に強脱酸し
ておくことが望ましい、また、取鍋上置スラグとして、
例えばＣａ０−ＣａＦｚ系もしくはＣａＯ−Ａｌ１ ｔ
ＯｘＣａＦｘ系フラックスを添加する。In the present invention, molten steel is treated with AQ, St, and Mn before adding Ca at the time of steel tapping in a converter or in an RH degassing treatment device.
The degree of deoxidation is not particularly limited, but from the viewpoint of molten steel cleanliness,
[AQ] ” It is desirable to deoxidize strongly at trace or higher level. Also, as ladle top slag,
For example, Ca0-CaFz system or CaO-Al1t
Add OxCaFx type flux.
なお、本発明において用いる溶鋼の組成は特に限定を要
するものではないが、前述のように、例えば硫化水素環
境下で使用される部材用としては、Ｃ： ０．０３〜０
．０１５、Ｓｉ ： ０．２０〜０．４０％、Ｍｎ ：
１．２０〜１．６０％、Ｐ ： ０．００５〜０．０
１５ ％、Ｓ ： ０．０００３〜０．０００７％等の
組成を例示することができる。The composition of the molten steel used in the present invention is not particularly limited, but as mentioned above, for example, for parts used in a hydrogen sulfide environment, C: 0.03 to 0.
．． 015, Si: 0.20-0.40%, Mn:
1.20-1.60%, P: 0.005-0.0
15%, S: 0.0003 to 0.0007%, and the like.
次いで、この溶鋼にＣａ合金粉末、例えばＣａＳｉ粉末
を吹き込み、脱酸、脱硫および介在物の形態制御を行う
、また、Ｃａ合金粉末としてのＣ５ｄｉ粉末の＆ｌｌ戒
は、特に限定を要するものではないが、Ｓｉ：５０〜６
５％、Ｃａ：２５〜３５％程度である。Next, Ca alloy powder, such as CaSi powder, is injected into this molten steel to perform deoxidation, desulfurization, and control of the form of inclusions.Although the precepts of C5di powder as Ca alloy powder are not particularly limited, , Si:50-6
5%, Ca: about 25 to 35%.
さらに、ＣａＳ＋粉末以外のＣａ合金粉末としては、Ｃ
ａＡＱ等を例示することができる。Furthermore, as Ca alloy powder other than CaS+ powder, C
An example is aAQ.
前述のようにして、Ｃａ合金粉末を吹き込んだ際、吹き
込んだＣａ合金粉末の量を従来の、Ｃａ合金粉末の吹込
処理のみを行う場合、あるいは、特公昭５９−２２７６
５号公報により提案された方法のようにＣａＯ含有フラ
ックス吹込み後にＣａ合金を吹込む場合よりも増加して
吹き込むことにより脱硫効果の向上が実現するが、その
理由として以下の項目が挙げられる。When Ca alloy powder is injected as described above, the amount of injected Ca alloy powder may be changed by conventional blowing treatment of Ca alloy powder only, or by
As in the method proposed in Publication No. 5, the desulfurization effect is improved by increasing the amount of Ca alloy injected after injecting the CaO-containing flux, and the reasons for this are as follows.
まず、第１点として、Ｃａ合金粉末の吹込量が増加する
ことによりＣａ合金粉末吹込時に発生するＣａ華気が増
加し、溶鋼の攪拌力が増加することである。脱硫反応は
スラグ−メタル反応であるため、攪拌力が強い程反応に
有利だからである。First, as the amount of Ca alloy powder injected increases, Ca blooms generated when Ca alloy powder is injected increase, and the stirring force of the molten steel increases. This is because the desulfurization reaction is a slag-metal reaction, so the stronger the stirring force, the more advantageous the reaction is.
第２点は、蒸発したＣａにより、スラグ中の低級酸化物
（ＦｅＯおよびＭｎ０）が強還元されることである０通
常、スラグの改質にはＡＱ添加による方法が一般的であ
るが、本発明においては蒸発したＣａによりスラグ中の
低級酸化物のより一層の低減が実現する。第１図に、Ｓ
分配比（＝（Ｓ）／［５］ 、ただし、（）はスラグ中
のＳ濃度を、［］は溶鋼中のＳ１度をそれぞれ示す）と
スラグ中の低級酸化物（（Ｆｅｄ） ＋ （ＭｎＯ）
）の重量比との関係を示すが、低級酸化物置が低下する
程Ｓ分配比が大きくなり、脱硫に有利となることを表わ
している。したがって、Ｃａ合金粉末の吹き込み量を増
加することによりスラグ中の低級酸化物量が減少し、脱
硫に有利に作用するのである。The second point is that the lower oxides (FeO and Mn0) in the slag are strongly reduced by the evaporated Ca.Normally, slag modification is commonly done by adding AQ, but this method In the invention, the evaporated Ca realizes a further reduction in lower oxides in the slag. In Figure 1, S
The distribution ratio (=(S)/[5], where () indicates the S concentration in the slag, and [] indicates the S1 degree in the molten steel) and the lower oxides in the slag ((Fed) + (MnO) )
), it shows that the lower the lower oxide content, the larger the S distribution ratio becomes, which is more advantageous for desulfurization. Therefore, by increasing the amount of Ca alloy powder blown into the slag, the amount of lower oxides in the slag is reduced, which has an advantageous effect on desulfurization.
なお、Ｃａ合金粉末のみの吹込みを行う方法、または特
公昭５９−２２７６５号公報により提案された方法は、
いわば脱硫工程の最後のＣａ合金を吹き込む方法である
ため、本発明の如くにＣａ合金粉末の吹込み量を増加す
ることができない、吹込み後の溶鋼の清浄度が、吹込ま
れたＣａまたは介在物により、著しく低下してしまうか
らである。Note that the method of injecting only Ca alloy powder or the method proposed in Japanese Patent Publication No. 59-22765 is as follows:
Since this is a method in which Ca alloy is injected at the end of the desulfurization process, the amount of Ca alloy powder injected cannot be increased as in the present invention, and the cleanliness of the molten steel after blowing may be affected by the injected Ca or intervening particles. This is because depending on the material, the value may drop significantly.
また、本発明においては、このＣａ合金粉末の添加によ
り、ＣａＯ−１１Ｊ！□Ｏ３系酸化物を生成する。この
ＣａＣＩＰＪｌ□Ｏ８系酸化物は球状であるため、鋼中
にあっても圧延時に変形しない、したがって、鋼中への
水素の集積を効果的に抑制することができ、得られる鋼
材の耐ＨＩＣ性を著しく改善することができる。すなわ
ち、本発明においては、酸化物形層を効率的に制御する
ことができる。Moreover, in the present invention, by adding this Ca alloy powder, CaO-11J! □O3-based oxides are produced. Since this CaCIPJl□O8-based oxide is spherical, it does not deform during rolling even if it is in the steel. Therefore, it can effectively suppress the accumulation of hydrogen in the steel, and the HIC resistance of the resulting steel material can be significantly improved. That is, in the present invention, the oxide type layer can be efficiently controlled.
また、脱硫の面からはＣａ合金粉末の添加量は１．５に
／Ｔ以上が望ましく、かつ成品におけるＣａ量は、Ｍｎ
Ｓの生成抑制およびＣａＳクラスター系介在物の抑制の
観点から１５〜４０ｐｐ−の範囲が望ましいことから、
Ｃａ合金粉末の添加量は１．７ Ｋ／Ｔ以下が望ましい
。したがって、合金粉末の添加量は１．５〜１．７に／
Ｔの範囲の吹き込みを行うことが望ましい。In addition, from the viewpoint of desulfurization, it is desirable that the amount of Ca alloy powder added is 1.5/T or more, and the amount of Ca in the product is Mn
From the viewpoint of suppressing the production of S and suppressing CaS cluster inclusions, a range of 15 to 40 pp- is desirable;
The amount of Ca alloy powder added is preferably 1.7 K/T or less. Therefore, the amount of alloy powder added is 1.5 to 1.7/
It is desirable to perform blowing in the T range.
このようにして、Ｃａ合金粉末を吹き込んだ後、引き続
いてＣａＯ含有含有ブランクスて、例えばＣａｂ、 Ｃ
ａＯ＋ＣａＦｚを吹込む。これは、Ｃａ合金粉末の吹き
込みにより生じたＣａＯＡＱｚＣｈ系介在物の凝集、浮
上を促進するのが主目的であるが、これ以外にもＣａ合
金粉末の吹き込みによって上置スラグの強還元が完了し
た状態でＣａＯフラックスを吹込むことにより、さらに
脱硫を進行させて、鋼の清浄度を高めることに一層効果
があるため、ｍ硫の促進をも百的としている。In this way, after injecting the Ca alloy powder, a CaO-containing blank is subsequently produced, for example with Cab, C
Inject aO+CaFz. The main purpose of this is to promote the agglomeration and flotation of CaOAQzCh-based inclusions generated by the injection of Ca alloy powder, but it also aims to promote the agglomeration and flotation of CaOAQzCh-based inclusions produced by injection of Ca alloy powder. By injecting CaO flux, desulfurization is further progressed and it is more effective in increasing the cleanliness of the steel, so the promotion of m-sulfur is also made a priority.
なお、本発明において、ＣａＯ含有含有ブランクスえば
、Ｃａ Ｏ、Ｃａ Ｏ＋Ｃａｒｔ）の吹き込み量として
は、１．０〜２．ＯＫ／Ｔが望ましい、吹き込み量が１
．０ＫＩＴ未満では介在物の浮上が不充分であり、また
２、ＯＫ／Ｔ超では必要以上であって、処理中の溶鋼の
温度低下が著しくなるからである。In the present invention, in the case of CaO-containing blanks, the amount of blown CaO (CaO, CaO+Cart) is 1.0 to 2. OK/T is desirable, blowing amount is 1
．． If it is less than 0 KIT, the floating of inclusions will be insufficient, and if it exceeds 2.OK/T, it will be more than necessary and the temperature of the molten steel during treatment will drop significantly.
さらに、ＣａＯ−ＣａＦ２フラックス中のＣａＦ ｔが
５％未満ではフラックスの滓化の面で不十分であり、Ｃ
ａＦｚが３０％超ではランスやスノーケル等の耐火物の
ダメージが大きくなってしまうため、ＣａＯ−ＣａＦ、
系フラックスを吹き込む場合には、ＣａＦ、量は５％以
上３０％以下とすることが望ましい。Furthermore, if CaFt in the CaO-CaF2 flux is less than 5%, it is insufficient in terms of flux slag formation, and C
If aFz exceeds 30%, damage to refractories such as lances and snorkels will increase, so CaO-CaF,
When a system flux is injected, the amount of CaF is desirably 5% or more and 30% or less.
以上説明したように、本発明によりＣａ合金粉末の吹き
込み、およびＣａＯ含有含有ブランクスき込みを連続的
に行うことにより、徹底した脱硫にょる極低硫化、Ｃａ
による介在物形態の制御、さらには介在物の浮上促進に
よる溶鋼清浄化を実現する二とができる。As explained above, according to the present invention, by continuously injecting Ca alloy powder and inserting CaO-containing blank, extremely low sulfidation due to thorough desulfurization, Ca
This makes it possible to control the form of inclusions and to clean molten steel by promoting the floating of inclusions.
さらに、本発明を実施例を用いて説明するが、これはあ
くまでも本発明の例示であって、これにより本発明が限
定されるものではない。Further, the present invention will be explained using examples, but these are merely illustrative of the present invention, and the present invention is not limited thereby.
実施例
転炉出鋼時にＡＱ脱酸処理を実施した溶鋼に対し、スラ
グ更新後、ＲＫ脱ガス処理により、脱水素、昇熱および
合金Ｖ＆副調整行った。Example Molten steel was subjected to AQ deoxidation treatment at the time of steel tapping in a converter, and after slag renewal, RK degassing treatment was performed to perform dehydrogenation, heat raising, and alloy V& sub-adjustment.
その後、Ｃａ合金粉末の吹き込みを、以下に示すように
して行った。第２図は、このＣａ合金粉末の吹き込みに
使用した装置の概要を示す略式説明図である。中央部に
設けたランス１よりＡｒガスもしくはＣａ合金粉末の吹
き込みを実施し、その周囲をスノーケル２で囲い、Ａｒ
バージにてシールすることにより、空気の巻き込みによ
る［＋１］アンプや酸素吸収を防止している。なお、第
２図においては、３は取鍋、４はスラグ、さらに５は溶
鋼をそれぞれ示す。Thereafter, Ca alloy powder was injected as shown below. FIG. 2 is a schematic explanatory diagram showing an outline of the apparatus used for blowing this Ca alloy powder. Ar gas or Ca alloy powder is injected from lance 1 installed in the center, surrounded by snorkel 2, and Ar
By sealing with a barge, [+1] amp and oxygen absorption due to air entrainment is prevented. In FIG. 2, 3 indicates a ladle, 4 indicates slag, and 5 indicates molten steel.
すなわち、上置スラグを滓化させるために事前にＡｒガ
ス吹き込みを１〜３分実施した後、Ｃａ−Ｓｉ合金粉末
（Ｃａ ’ｉ ３０％）を１．５〜２．ＯＫ／丁の範囲
で変化させて吹き込んだ。That is, after carrying out Ar gas blowing for 1 to 3 minutes in advance to turn the overlying slag into slag, Ca-Si alloy powder (Ca'i 30%) is injected for 1.5 to 2 minutes. I changed the sound in the range of OK/Ding.
その後、ＣａＦ１分が１５％のＣａＯ−ＣａＦｚ系フラ
ックスヲｉ、ｏ〜２．ＯＫ／Ｔの範囲で添加した。After that, CaO-CaFz-based flux with 15% CaF1, o~2. It was added within the range of OK/T.
さらに、ＣａＯ−ＣａＦｚ系フラックスの吹き込み後、
Ａｒガス流量が５００１１１ ／ｓｉｎ程度での吹き込
みを実施して、介在物浮上をさらに促進した。Furthermore, after blowing CaO-CaFz-based flux,
Blowing was carried out at an Ar gas flow rate of about 500111/sin to further promote inclusion flotation.
このようにして行った本実施例において、溶鋼中の脱硫
率と吹き込みＣａ５ｉｉｌとの関係を第３図に、成品（
Ｃａ ］量と吹き込みＣａ５ｔ量との関係を第４図に、
それぞれグラフで示す。In this example conducted in this way, the relationship between the desulfurization rate in molten steel and the blown Ca5iil is shown in Figure 3.
The relationship between the Ca] amount and the blown Ca5t amount is shown in Figure 4.
Each is shown in a graph.
第３図および第４図から明らかなように、ＣａＳｉ量ハ
、１．５〜１．７に／Ｔの範囲が好ましいことがわかる
。As is clear from FIGS. 3 and 4, it is found that the CaSi content is preferably in the range of 1.5 to 1.7/T.
また、フラックスを用いな９）従来のＣａＳｉ単独吹込
法による脱硫と本発明にかかる方法による脱硫とを比較
するため、成品（Ｓ）量の分布を比較して示したのが第
５図に示すグラフであるが、第５図により、本発明によ
り脱硫の大幅な向上が認められる。In addition, in order to compare the desulfurization by the conventional CaSi single injection method without using flux and the desulfurization by the method according to the present invention, the distribution of the amount of product (S) is compared and shown in Figure 5. As shown in FIG. 5, the present invention significantly improves desulfurization.
また、成品介在物の成績を、従来のＣａＳｉ粉末の単独
の吹き込み法と本発明にかかる方法とについて比較して
第６図にグラフで示す。Further, the results of product inclusions are shown in a graph in FIG. 6, comparing the conventional method of blowing CaSi powder alone and the method according to the present invention.
第６図より、本発明により介在物低減が実現し、優秀な
成品成績を収めていることがわかる。なお、第６図にお
いて、介在物指数は、介在物集積部の介在物個数および
表層下ブリスター個数により求めた。From FIG. 6, it can be seen that the present invention has achieved a reduction in inclusions and achieved excellent product results. In FIG. 6, the inclusion index was determined from the number of inclusions in the inclusion accumulation area and the number of blisters under the surface layer.
さらに、特公昭５９−２２７６５号公報により提案され
た方法と本発明にかかる方法とについて、上記の手順と
同様の手順で、成品介在物指数を調査し、その結果を第
７図にグラフで示す。Furthermore, the product inclusion index was investigated using the method proposed in Japanese Patent Publication No. 59-22765 and the method according to the present invention using the same procedure as above, and the results are shown graphically in FIG. .
第７図より、本発明により、特公昭５９−２２７６５号
公報により提案された方法よりも、より一層の介在物の
低減を実現することができたことがわか（発明の効果）
本発明は、以上説明したとおりに構成されているから、
介在物低減、極低硫化が図られ、耐水素誘起割れ性に優
れた清浄鋼を、特定の組成の合金鋼以外についても得る
ことが可能となった。From FIG. 7, it can be seen that the present invention was able to achieve a further reduction in inclusions than the method proposed in Japanese Patent Publication No. 59-22765 (Effects of the Invention). Since it is configured as explained above,
It has become possible to obtain clean steel with reduced inclusions and extremely low sulfidation and excellent resistance to hydrogen-induced cracking, even for steels other than alloy steels with specific compositions.
かかる効果を有する本発明の意義は極めて著しいThe significance of the present invention having such effects is extremely significant.
第１図は、硫黄分配比（（Ｓ）／［Ｓ］）とスラグ中低
級酸化物［（ＦｅＯ） ＋ （ＭｎＯ） ］ との関
係を示すグラフ；第２図は、本発明の実施に使用する装
置の一例の概要の略式説明図；
第３図は、本発明における、吹込Ｃａ５ｔ量と脱硫率と
の関係を示すグラフ；
第４図は、本発明における、吹込ＣａＳｉ量と成品中Ｃ
ａ含有量との関係を示すグラフ；
第５図は、本発明方法と従来法との成品［Ｓ）を比較し
て示すグラフ；および
第６図および第７図は、本発明方法と従来法との、それ
ぞれによる介在物量の分布を比較して示すグラフである
。
１：ランス
２ニスノーケル
３：取鍋
４ニスラグ
５・溶鋼
基１図Figure 1 is a graph showing the relationship between the sulfur distribution ratio ((S)/[S]) and lower oxides [(FeO) + (MnO)] in the slag; Figure 2 is a graph showing the relationship between the sulfur distribution ratio ((S)/[S]) and lower oxides [(FeO) + (MnO)] in the slag; A schematic explanatory diagram of an example of an apparatus for performing this process; FIG. 3 is a graph showing the relationship between the blown Ca5t amount and the desulfurization rate in the present invention; FIG. 4 is a graph showing the relationship between the blown CaSi amount and the C in the product in the present invention
A graph showing the relationship between the a content and the a content; FIG. 5 is a graph showing a comparison of the product [S) obtained by the method of the present invention and the conventional method; and FIGS. 6 and 7 are the graphs showing the relationship between the method of the present invention and the conventional method. FIG. 2 is a graph showing a comparison of the distribution of the amount of inclusions in each case. 1: Lance 2 Varnish snorkel 3: Ladle 4 Varnish slug 5/molten steel base 1 diagram
Claims (1)
ることにより脱酸、脱硫および硫化物形態の制御を行っ
た後、引き続いて該溶鋼にＣａＯ含有フラックスを添加
し、脱硫および介在物の浮上を促進することを特徴とす
る耐水素誘起割れ性の優れた清浄鋼の製造方法。After deoxidizing, desulfurizing, and controlling the sulfide form by adding Ca alloy powder to the molten steel that has been previously deoxidized in the ladle, a CaO-containing flux is subsequently added to the molten steel to remove sulfur and inclusions. A method for producing clean steel with excellent resistance to hydrogen-induced cracking, characterized by promoting levitation of.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9368590A JPH0696734B2 (en) | 1990-04-09 | 1990-04-09 | Method for producing clean steel with excellent resistance to hydrogen-induced cracking |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9368590A JPH0696734B2 (en) | 1990-04-09 | 1990-04-09 | Method for producing clean steel with excellent resistance to hydrogen-induced cracking |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03291323A true JPH03291323A (en) | 1991-12-20 |
| JPH0696734B2 JPH0696734B2 (en) | 1994-11-30 |
Family
ID=14089264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9368590A Expired - Fee Related JPH0696734B2 (en) | 1990-04-09 | 1990-04-09 | Method for producing clean steel with excellent resistance to hydrogen-induced cracking |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0696734B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08225824A (en) * | 1995-02-23 | 1996-09-03 | Sumitomo Metal Ind Ltd | Desulfurization of molten steel |
| CN100371464C (en) * | 2006-06-02 | 2008-02-27 | 重庆大学 | Molten steel composite refining agent |
| JP2015183202A (en) * | 2014-03-20 | 2015-10-22 | 新日鐵住金株式会社 | Desulfurization treatment method for molten steel |
-
1990
- 1990-04-09 JP JP9368590A patent/JPH0696734B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08225824A (en) * | 1995-02-23 | 1996-09-03 | Sumitomo Metal Ind Ltd | Desulfurization of molten steel |
| CN100371464C (en) * | 2006-06-02 | 2008-02-27 | 重庆大学 | Molten steel composite refining agent |
| JP2015183202A (en) * | 2014-03-20 | 2015-10-22 | 新日鐵住金株式会社 | Desulfurization treatment method for molten steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0696734B2 (en) | 1994-11-30 |
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