JPH10237598A - Austenitic stainless steel low in working crack sensitivity and its production - Google Patents
Austenitic stainless steel low in working crack sensitivity and its productionInfo
- Publication number
- JPH10237598A JPH10237598A JP9039027A JP3902797A JPH10237598A JP H10237598 A JPH10237598 A JP H10237598A JP 9039027 A JP9039027 A JP 9039027A JP 3902797 A JP3902797 A JP 3902797A JP H10237598 A JPH10237598 A JP H10237598A
- Authority
- JP
- Japan
- Prior art keywords
- weight
- less
- stainless steel
- inclusions
- cao
- 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
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、加工割れ感受性が低い
オーステナイト系ステンレス鋼及びその製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an austenitic stainless steel having low susceptibility to work cracking and a method for producing the same.
【０００２】[0002]
【従来の技術】加工性に優れたオーステナイト系ステン
レス鋼は、近年、機能材料としても使用されるようにな
ってきている。オーステナイト系ステンレス鋼の中で
も、常温で非磁性の鋼種は、電子部品用材料として使用
されることが多い。この種の材料には、高い清浄度が要
求される。そのため、素材製造時の精錬工程で不活性ガ
スの吹込みにより溶鋼を十分撹拌しながら、ＣａＯを主
体とする塩基性フラックス及びＡｌ等の強還元剤を添加
し、脱硫，脱酸及び非金属介在物除去を十分に行わせて
いる。たとえば、特開平６−３０６４３８号公報では、
二次精錬炉の耐火物を特定すると共に精錬後のスラグ組
成を調整することにより、有害なＡｌ2 Ｏ3 −ＭｇＯ系
非金属介在物の生成を抑制している。このような処理に
よって、ある程度まで高清浄度化される。2. Description of the Related Art In recent years, austenitic stainless steel excellent in workability has been used as a functional material in recent years. Of the austenitic stainless steels, a nonmagnetic steel at room temperature is often used as a material for electronic components. This type of material requires high cleanliness. For this reason, in a refining process during the production of a raw material, a basic flux mainly composed of CaO and a strong reducing agent such as Al are added while sufficiently stirring the molten steel by blowing an inert gas to desulfurize, deoxidize, and intervene with nonmetals. The material is sufficiently removed. For example, in JP-A-6-306438,
By adjusting the slag composition after refining with identifying a refractory secondary refining furnace, thereby suppressing generation of harmful Al 2 O 3 -MgO based nonmetallic inclusions. By such processing, the degree of cleanliness is increased to some extent.
【０００３】[0003]
【発明が解決しようとする課題】電子部品用材料に供さ
れる素材の中でも、鋼板の板厚が０．５ｍｍ程度以下の
極薄で製品形状が複雑なものでは、加工時に僅かな割れ
や表面疵が発生しても、製品として使用不可となる。そ
のため、機能材料として用いられる用途では、加工精度
や品質に対する要求が苛酷である。加工割れや表面疵
は、硬質な非金属介在物に原因があることが多い。しか
し、精錬工程で溶鋼を強撹拌することにより非金属介在
物を完全に浮上分離することは困難である。また、非金
属介在物の硬さは組成によって大きく変わるが、生成す
る非金属介在物の組成までを制御してない。本発明は、
このような問題を解消すべく案出されたものであり、非
金属介在物の組成を制御することにより、熱間加工時に
粘性変形し冷間加工時に微細分散するＭｎＯ−ＳｉＯ2
系にし、非金属介在物起因の加工割れがないオーステナ
イト系ステンレス鋼を得ることを目的とする。Among the materials used for electronic component materials, if the thickness of a steel sheet is extremely thin, such as about 0.5 mm or less, and the product shape is complicated, slight cracks or surface cracks may occur during processing. Even if a flaw occurs, it cannot be used as a product. Therefore, in applications used as functional materials, demands on processing accuracy and quality are severe. Work cracks and surface flaws are often caused by hard non-metallic inclusions. However, it is difficult to completely float and separate nonmetallic inclusions by vigorously stirring molten steel in the refining process. Further, the hardness of nonmetallic inclusions varies greatly depending on the composition, but the composition of the nonmetallic inclusions to be formed is not controlled. The present invention
MnO—SiO 2 , which is devised to solve such a problem, viscously deforms during hot working and finely disperses during cold working by controlling the composition of nonmetallic inclusions.
It is an object to obtain an austenitic stainless steel free from working cracks caused by nonmetallic inclusions.
【０００４】[0004]
【課題を解決するための手段】本発明のオーステナイト
系ステンレス鋼は、その目的を達成するため、Ｃ：０．
０８重量％以下，Ｓｉ：０．２〜１．０重量％，Ｍｎ：
２．０重量％以下，Ｓ：０．００７重量％以下，Ｎｉ：
８．０〜１５．０重量％，Ｃｒ：１５．０〜１９．０重
量％，Ｎ：０．０３重量％以下，Ａｌ：０．００３重量
％以下，残部が実質的にＦｅの組成を持ち、Ｓｉ／Ａｌ
の重量比が１００以上で、非金属介在物の組成がＭｎＯ
−ＳｉＯ2 を主成分とし、ＭｇＯ：７重量％以下，Ａｌ
2 Ｏ3 ：３５重量％以下，Ｃｒ2 Ｏ3 ：１０重量％以下
であることを特徴とする。このオーステナイト系ステン
レス鋼は、ドロマイト系耐火物をライニングした精錬炉
を用いてステンレス溶鋼を精錬し、精錬終了後のスラグ
のＣａＯ／ＳｉＯ 2 比を１．４〜２．４に、Ａｌ2 Ｏ3
濃度を８重量％以下に維持することにより製造される。
ドロマイト系耐火物には、ＭｇＯ：４０〜６３重量％及
び主成分としてＣａＯ：３４〜５７重量％を含む耐火物
が使用される。SUMMARY OF THE INVENTION Austenite of the present invention
Series stainless steel has a C: 0.
08% by weight or less, Si: 0.2 to 1.0% by weight, Mn:
2.0% by weight or less, S: 0.007% by weight or less, Ni:
8.0-15.0% by weight, Cr: 15.0-19.0 weight
%, N: 0.03% by weight or less, Al: 0.003% by weight
% Or less, and the balance substantially has a composition of Fe,
And the composition of the nonmetallic inclusions is MnO
-SiOTwo With MgO: 7% by weight or less, Al
Two OThree : 35% by weight or less, CrTwo OThree : 10% by weight or less
It is characterized by being. This austenitic stainless steel
Less steel is a smelting furnace lined with dolomite-based refractories
Refining of molten stainless steel using slag
CaO / SiO Two Al ratio to 1.4-2.4Two OThree
Produced by maintaining the concentration below 8% by weight.
Dolomite refractories contain MgO: 40-63% by weight.
And refractory containing 34 to 57% by weight of CaO as a main component
Is used.
【０００５】[0005]
【作用】本発明者等は、オーステナイト系ステンレス鋼
に絞り加工を施して得た製品について、非金属介在物に
由来する加工割れが発生しているものを調査した。オー
ステナイト系ステンレス鋼に分散している非金属介在物
は、通常、約３０重量％のＭｇＯを含むスピネル型Ａｌ
2 Ｏ3 −ＭｇＯ系，約５０重量％のＡｌ2Ｏ3 を含むＭ
ｎＯ−ＳｉＯ2 −Ａｌ2 Ｏ3 系，約１５重量％のＣｒ2
Ｏ3 を含むＭｎＯ−ＳｉＯ2 系である。本発明者等によ
る調査・研究の結果、これらの介在物に含まれるＡｌ2
Ｏ3 濃度，ＭｇＯ濃度及びＣｒ2 Ｏ3 濃度が加工割れに
大きく影響していることが判った。そして、ＭｎＯ−Ｓ
ｉＯ2 を主成分とする非金属介在物を生成させると共
に、ＭｇＯ：７重量％以下，Ａｌ2 Ｏ3 ：３５重量％以
下，Ｃｒ2 Ｏ3 ：１０重量％以下に調整するとき、非金
属介在物が無害化し、加工割れ感受性の低いオーステナ
イト系ステンレス鋼が得られることを見い出した。更
に、介在物組成に影響を及ぼす因子としてメタル組成，
スラグ組成，耐火物組成等について検討を進めたとこ
ろ、精錬終了後のスラグ組成及び取鍋の耐火物組成を特
定することが有効であることが判った。The present inventors have investigated a product obtained by subjecting austenitic stainless steel to drawing processing, in which a processing crack originating from nonmetallic inclusions has occurred. Non-metallic inclusions dispersed in austenitic stainless steel are typically spinel-type Al containing about 30% by weight MgO.
2 O 3 —MgO based, M containing about 50% by weight of Al 2 O 3
nO—SiO 2 —Al 2 O 3 system, about 15% by weight of Cr 2
It is a MnO—SiO 2 system containing O 3 . As a result of investigation and research by the present inventors, Al 2 contained in these inclusions
It was found that the O 3 concentration, the MgO concentration, and the Cr 2 O 3 concentration greatly affected the work crack. And MnO-S
When non-metallic inclusions containing iO 2 as a main component are generated and MgO: 7% by weight or less, Al 2 O 3 : 35% by weight or less, Cr 2 O 3 : 10% by weight or less, It has been found that the material is rendered harmless and an austenitic stainless steel having low work cracking susceptibility can be obtained. In addition, metal composition,
Examination of the slag composition, refractory composition, and the like revealed that it is effective to specify the slag composition after refining and the refractory composition of the ladle.
【０００６】以下、本発明オーステナイト系ステンレス
鋼に含まれる合金成分，含有量等を説明する。 Ｃ：０．０８重量％以下 固溶強化元素であり、多量に含まれると０．２％耐力が
上昇し、鋼材を硬質化する。絞り加工が供される鋼材で
は、耐力及び硬さの上昇により加工性が阻害され、加工
時に耳割れを発生させることもある。そこで、本発明に
おいては、Ｃ含有量の上限を０．０８重量％に設定し
た。 Ｓｉ：０．２〜１．０重量％ 溶鋼の脱酸に使用される成分であり、０．２重量％未満
では脱酸不足となる。そして、非金属介在物中のＣｒ2
Ｏ3 濃度が１０重量％よりも高くなり、加工割れ原因の
非金属介在物が生成する。しかし、１．０重量％を超え
る多量のＳｉが含まれると、鋼材が硬質化し、冷間加工
で薄板を製造する際に所定板厚まで圧延するために多く
のパス回数を必要とし、生産性が大きく低下する。ま
た、鋼材の硬質化に伴って、絞り加工時に耳割れが発生
することもある。Hereinafter, alloy components and contents contained in the austenitic stainless steel of the present invention will be described. C: 0.08% by weight or less Solid solution strengthening element. When contained in a large amount, the proof stress increases by 0.2% and hardens the steel material. In a steel material subjected to drawing, workability is impaired due to an increase in proof stress and hardness, and ear cracks may be generated during processing. Therefore, in the present invention, the upper limit of the C content is set to 0.08% by weight. Si: 0.2 to 1.0% by weight It is a component used for deoxidizing molten steel, and if less than 0.2% by weight, deoxidation is insufficient. And Cr 2 in nonmetallic inclusions
The O 3 concentration becomes higher than 10% by weight, and non-metallic inclusions causing work cracks are generated. However, when a large amount of Si exceeding 1.0% by weight is contained, the steel material becomes hard and requires a large number of passes to roll to a predetermined thickness when manufacturing a thin plate by cold working, and thus the productivity is increased. Greatly decreases. In addition, with the hardening of the steel material, ear cracks may occur during drawing.
【０００７】Ｍｎ：２．０重量％以下 熱間加工性の確保に有効な合金成分であり、０．２％耐
力を低下させ、鋼材を軟質化する作用も呈する。Ｍｎ添
加の効果は、２．０重量％で飽和し、それ以上添加して
も増量に見合った性質改善がみられない。 Ｓ：０．００７重量％以下 熱間加工性に悪影響を及ぼす元素であることから、Ｓ含
有量の上限を０．００７重量％に規制した。なお、一層
良好な熱間加工性を得るためには、Ｓ含有量を０．００
５重量％以下に規制することが好ましい。 Ｎｉ：８．０〜１５．０重量％ オーステナイト系ステンレス鋼の主要合金成分であり、
加工性及び常温非磁性を確保するために８．０重量％以
上のＮｉ量が必要である。しかし、高価な元素であるこ
とから、Ｎｉの多量添加は鋼材コストを上昇させる原因
となる。また、１５．０重量％を超えると、却って非磁
性化できなくなる。Mn: 2.0% by weight or less Mn is an alloy component effective for ensuring hot workability, and also has an effect of reducing proof stress by 0.2% and softening steel. The effect of the addition of Mn is saturated at 2.0% by weight, and even if it is added more than that, no improvement in properties commensurate with the increase is observed. S: 0.007% by weight or less Since the element has an adverse effect on hot workability, the upper limit of the S content is regulated to 0.007% by weight. In order to obtain better hot workability, the S content should be 0.00
It is preferable to limit the content to 5% by weight or less. Ni: 8.0-15.0% by weight It is a main alloy component of austenitic stainless steel,
In order to ensure workability and non-magnetic properties at room temperature, a Ni content of 8.0% by weight or more is required. However, since it is an expensive element, the addition of a large amount of Ni causes an increase in steel material cost. On the other hand, if it exceeds 15.0% by weight, it becomes impossible to demagnetize it.
【０００８】Ｃｒ：１５．０〜１９．０重量％ 耐食性の改善に必要な合金成分であり、１５．０重量％
以上の含有量でＣｒ添加の効果が顕著になる。しかし、
過剰量のＣｒが含まれると鋼材が硬質化し、加工性が劣
化することから、本発明ではＣｒ含有量の上限を１９．
０重量％に設定した。Cr: 15.0 to 19.0% by weight An alloy component necessary for improving corrosion resistance, and 15.0% by weight.
With the above content, the effect of adding Cr becomes remarkable. But,
If an excessive amount of Cr is contained, the steel material becomes hard and the workability deteriorates. Therefore, in the present invention, the upper limit of the Cr content is set to 19.
It was set to 0% by weight.
【０００９】Ｎ：０．０３重量％以下 Ｃと同様な固溶強化元素であり、多量に含まれると０．
２％耐力が上昇し、鋼材を硬質化する。絞り加工が供さ
れる鋼材では、耐力及び硬さの上昇により加工性が阻害
され、加工時に耳割れを発生させることもある。そこ
で、本発明においては、Ｎ含有量の上限を０．０３重量
％に設定した。 Ａｌ：０．００３重量％以下 加工割れの起点となる非金属介在物の組成に大きく影響
する成分である。Ａｌ含有量が０．００３重量％を超え
ると、有害な非金属介在物が生成し易くなる。 Ｓｉ／Ａｌの重量比：１００以上 加工割れの起点となる非金属介在物の組成は、Ｓｉ／Ａ
ｌの重量比で調整できる。Ｓｉ／Ａｌ＜１００では有害
な非金属介在物が生成するが、Ｓｉ／Ａｌ≧１００にす
ると熱間加工時に粘性変形し冷間加工時に微細分散する
ＭｎＯ−ＳｉＯ2 系非金属介在物になる。N: 0.03% by weight or less N is a solid solution strengthening element similar to C.
The proof stress increases by 2% and hardens the steel material. In a steel material subjected to drawing, workability is impaired due to an increase in proof stress and hardness, and ear cracks may be generated during processing. Therefore, in the present invention, the upper limit of the N content is set to 0.03% by weight. Al: 0.003% by weight or less Al is a component that greatly affects the composition of nonmetallic inclusions that are the starting points of working cracks. When the Al content exceeds 0.003% by weight, harmful nonmetallic inclusions are easily generated. The weight ratio of Si / Al: 100 or more The composition of the nonmetallic inclusion that is the starting point of the work crack is Si / A
1 can be adjusted by weight ratio. When Si / Al <100, harmful nonmetallic inclusions are formed, but when Si / Al ≧ 100, MnO—SiO 2 -based nonmetallic inclusions are viscously deformed during hot working and finely dispersed during cold working.
【００１０】非金属介在物：ＭｎＯ−ＳｉＯ2 系にする
ことにより非金属介在物は無害化されるが、更にＭｇ
Ｏ：７重量％以下，Ａｌ2 Ｏ3 ：３５重量％以下，Ｃｒ
2 Ｏ3 ：１０重量％以下にすることにより加工割れ感受
性が一層改善される。ＭｇＯは、耐火物やスラグに含ま
れており、不可避的に介在物中に含まれることが多い。
ＭｇＯ濃度が７重量％を超えると、介在物が熱間加工中
に粘性変形しなくなり、加工割れの原因になり易い。こ
のような欠陥は、ＭｇＯ濃度を７重量％以下にすること
により抑制される。Ａｌ2 Ｏ3 は、種々の添加原料に含
まれているＡｌから生成すると考えられるが、Ａｌ2 Ｏ
3 も介在物中の濃度により介在物の変形能に大きな影響
を及ぼす。Ａｌ2 Ｏ3 濃度が３５重量％よりも高いと有
害な介在物が生成されるが、３５重量％以下であると介
在物は熱間圧延で粘性変形し、冷間圧延で微細分散する
ため加工割れを発生させることがない。Ｃｒ2 Ｏ3は、
１０重量％を超える濃度では加工割れ原因の介在物とな
るが、１０重量％以下の濃度では無害な介在物となる。Non-metallic inclusions: Non-metallic inclusions are rendered harmless by using MnO—SiO 2 system.
O: 7% by weight or less, Al 2 O 3 : 35% by weight or less, Cr
By setting the content of 2 O 3 to 10% by weight or less, the work cracking sensitivity is further improved. MgO is contained in refractories and slag, and is often inevitably contained in inclusions.
If the MgO concentration exceeds 7% by weight, the inclusions do not undergo viscous deformation during hot working, and tend to cause work cracking. Such defects are suppressed by setting the MgO concentration to 7% by weight or less. Al 2 O 3 is believed to produce an Al contained in various additive material, Al 2 O
3 also greatly affects the deformability of inclusions depending on the concentration in the inclusions. When the concentration of Al 2 O 3 is higher than 35% by weight, harmful inclusions are formed. However, when the concentration is less than 35% by weight, the inclusions are viscously deformed by hot rolling and finely dispersed by cold rolling. No cracks occur. Cr 2 O 3
Concentrations exceeding 10% by weight result in inclusions that cause processing cracks, while concentrations below 10% by weight result in harmless inclusions.
【００１１】精錬終了時のスラグ組成：精錬終了時のス
ラグ組成も、非金属介在物の組成に大きな影響を及ぼ
す。スラグ中のＣａＯ／ＳｉＯ2 比が１．４よりも低
く、且つＡｌ2 Ｏ3 濃度が８重量％以下の場合、介在物
の主組成がＭｎＯ−ＳｉＯ2 となり、加工割れに悪影響
を及ぼす介在物中のＡｌ2 Ｏ3 やＭｇＯが極く僅かに含
まれる程度になる。しかし、この場合でも、介在物にＣ
ｒ2 Ｏ3 が２０重量％程度含まれることがあり、加工割
れ原因になることがある。ＣａＯ／ＳｉＯ2 比が１．４
より低く且つＡｌ2 Ｏ3 濃度が８重量％を超えると、Ｍ
ｎＯ−Ａｌ2 Ｏ3 系の介在物が生成し易くなる。ＭｎＯ
−Ａｌ2 Ｏ3 系介在物は、変形能が良好でないため加工
割れの原因になる。一方、ＣａＯ／ＳｉＯ2 比が２．４
を超えるようなスラグ組成では、代表的な硬質介在物で
あるＭｇＯ−Ａｌ2 Ｏ3 系スピネル型介在物が生成し易
くなる。このようなことから、スラグ組成は、ＣａＯ／
ＳｉＯ2比を１．４〜２．４の範囲に、Ａｌ2 Ｏ3 濃度
を８重量％以下にする必要がある。Slag composition at the end of refining: Slag composition at the end of refining also has a significant effect on the composition of nonmetallic inclusions. When the CaO / SiO 2 ratio in the slag is lower than 1.4 and the Al 2 O 3 concentration is 8% by weight or less, the main composition of the inclusions is MnO—SiO 2 , and the inclusions that adversely affect the working crack Al 2 O 3 and MgO therein are contained only slightly. However, even in this case, C
r 2 O 3 may be contained in an amount of about 20% by weight, which may cause processing cracks. CaO / SiO 2 ratio of 1.4
At lower and Al 2 O 3 concentrations above 8% by weight, M
nO-Al 2 O 3 based inclusions are easily generated. MnO
-Al 2 O 3 based inclusions, causes machining cracks for deformability it is not good. On the other hand, when the CaO / SiO 2 ratio is 2.4
In slag composition exceeding the likely representative MgO-Al 2 O 3 spinel-type inclusions are hard inclusions generated. Therefore, the slag composition is CaO /
It is necessary that the SiO 2 ratio be in the range of 1.4 to 2.4 and the Al 2 O 3 concentration be 8 wt% or less.
【００１２】取鍋の耐火物：ＭｇＯ含有量が５０〜８５
重量％で残部の主成分がＣｒ2 Ｏ3 のマグクロ系耐火物
を取鍋耐火物として用いた場合、スラグ中のＣａＯ／Ｓ
ｉＯ2 比が１．９を超えると耐火物の溶損が大きくな
り、スラグ中のＭｇＯ濃度が上昇するため、介在物中の
ＭｇＯ濃度が高くなる。その結果、加工割れを招く介在
物になる可能性が高い。また、マグクロ系耐火物は十分
な脱硫能を有していないため、鋼中のＳ濃度規制が厳し
い場合、精錬によって成分規格を満足できない場合が生
じる。これに対し、ＭｇＯ含有量が４０〜６３重量％で
残部の主成分がＣａＯであるドロマイト系耐火物は、ス
ラグ中のＣａＯ／ＳｉＯ2 比の上昇によっても耐火物の
溶損が加速されないため、介在物組成に及ぼす悪影響が
小さく、また製造コストを低く抑えることもできる。更
に、十分な脱硫能をもっていることから、鋼中Ｓ規制を
精錬によって十分満足させることが可能になる。Refractory of ladle: MgO content is 50 to 85
When a magcro refractory whose main component is Cr 2 O 3 in weight% and a ladle refractory is used, CaO / S in the slag is used.
When the iO 2 ratio exceeds 1.9, the erosion of the refractory increases, and the MgO concentration in the slag increases, so that the MgO concentration in the inclusions increases. As a result, there is a high possibility that inclusions may cause work cracks. In addition, since magcro refractories do not have a sufficient desulfurization ability, when the S concentration in steel is strictly regulated, there may be cases where component specifications cannot be satisfied by refining. On the other hand, dolomite-based refractories having an MgO content of 40 to 63% by weight and the balance of the main component being CaO are not accelerated by the increase in the CaO / SiO 2 ratio in the slag. The adverse effect on the inclusion composition is small, and the production cost can be kept low. Further, since it has a sufficient desulfurization ability, it becomes possible to sufficiently satisfy the S regulation in steel by refining.
【００１３】[0013]
実施例１：表１に示した成分組成をもつオーステナイト
系ステンレス鋼を７０トン電気炉で溶解し、転炉処理，
ＶＯＤ精錬，連鋳，熱延，酸洗，冷延を経て、種々の非
金属介在物が分散した板厚３．０ｍｍのステンレス鋼薄
板を製造した。このステンレス鋼薄板に絞り比３の絞り
加工を施し、精錬時に生成したＣａＯ−ＳｉＯ2 系スラ
グの組成が非金属介在物の組成及び加工割れの発生有無
に及ぼす影響を調査した。Example 1 An austenitic stainless steel having the composition shown in Table 1 was melted in a 70-ton electric furnace, and was subjected to converter treatment.
Through VOD refining, continuous casting, hot rolling, pickling, and cold rolling, a stainless steel thin plate having a thickness of 3.0 mm in which various nonmetallic inclusions were dispersed was manufactured. This stainless steel sheet was subjected to drawing at a drawing ratio of 3, and the influence of the composition of CaO—SiO 2 slag generated during refining on the composition of nonmetallic inclusions and the presence or absence of processing cracks was investigated.
【００１４】 [0014]
【００１５】図１〜３の調査結果にみられるように、精
錬時のスラグに含まれるＡｌ2 Ｏ3の濃度及びＣａＯ／
ＳｉＯ2 の重量比が絞り加工時の加工割れに大きく影響
していることが判った。なお、図１〜３では、非金属介
在物に含まれる各成分の濃度を縦軸に示し、加工割れが
発生した場合を白抜き記号で、加工割れが発生しなかっ
た場合を中実記号で示した。図１，２から、スラグのＡ
ｌ2 Ｏ3 濃度が８．０重量％以下でＣａＯ／ＳｉＯ 2 比
が１．４より低い場合、ＭｎＯ−ＳｉＯ2 系の非金属介
在物が生成していることが判る。生成した非金属介在物
は、Ａｌ2 Ｏ3 （丸印）やＭｇＯ（四角印）を僅かに含
む程度であったが、約１３〜１８重量％のＣｒ2 Ｏ3
（三角印）を含んでいた。このことから、スラグのＡｌ
2 Ｏ3 濃度が８．０重量％以下でＣａＯ／ＳｉＯ2 比が
１．４より低いと、Ｃｒ2 Ｏ3 の還元が十分に進行せ
ず、加工割れの原因となる非金属介在物が生成するもの
と推察される。As can be seen from the survey results in FIGS.
Al contained in slag during smeltingTwo OThreeConcentration and CaO /
SiOTwo Weight ratio greatly affects cracking during drawing
I knew I was doing it. In addition, in FIGS.
The vertical axis shows the concentration of each component contained in the entity,
When it occurs, the outline symbol is used and machining crack does not occur
Are indicated by solid symbols. From Figures 1 and 2, the slag A
lTwo OThree CaO / SiO at a concentration of 8.0% by weight or less Two ratio
Is lower than 1.4, MnO—SiOTwo Non-metallic system
It turns out that the entity is generated. Non-metallic inclusions formed
Is AlTwo OThree (Circle) and MgO (square mark)
About 13 to 18% by weight of CrTwo OThree
(Triangle). From this, the slag Al
Two OThree CaO / SiO at a concentration of 8.0% by weight or lessTwo Ratio
If it is lower than 1.4, CrTwo OThree Reduction has progressed sufficiently
Non-metallic inclusions that cause processing cracks
It is inferred.
【００１６】Ｃｒ2 Ｏ3 の還元は、ＣａＯ／ＳｉＯ2 比
が大きくなるに従って減少しており、ＣａＯ／ＳｉＯ2
比が２．４を超える条件下では非金属介在物にほとんど
Ｃｒ 2 Ｏ3 が含まれていなかった。しかし、Ａｌ2 Ｏ3
濃度が約４２〜７０重量％，ＭｇＯ濃度が約２６〜３０
重量％になっていた。特にＣａＯ／ＳｉＯ2 比が２．６
以上になると、Ａｌ2 Ｏ3 濃度が約７０重量％，ＭｇＯ
濃度が約３０重量％の硬質なスピネル型介在物となって
いた。これらの非金属介在物が原因して、図１，２に示
すように加工割れが発生するものと推察される。また、
スラグ中のＡｌ2 Ｏ3 濃度が９．５重量％では、図３に
示すようにＣａＯ／ＳｉＯ2 比に拘らず、全ての条件下
で加工割れの原因となる非金属介在物が生成していた。CrTwo OThree Of CaO / SiOTwo ratio
Decreases as Ca increases, and CaO / SiOTwo
When the ratio exceeds 2.4, almost no nonmetallic inclusions
Cr Two OThree Was not included. However, AlTwo OThree
The concentration is about 42 to 70% by weight, and the MgO concentration is about 26 to 30.
Weight percent. Especially CaO / SiOTwo The ratio is 2.6
Above, AlTwo OThree Concentration is about 70% by weight, MgO
Hard spinel-type inclusions with a concentration of about 30% by weight
Was. Due to these non-metallic inclusions,
It is presumed that processing cracks occur as described above. Also,
Al in slagTwo OThree At a concentration of 9.5% by weight, FIG.
As shown, CaO / SiOTwo All conditions, regardless of ratio
In this case, non-metallic inclusions causing processing cracks were formed.
【００１７】これに対し、スラグ中のＡｌ2 Ｏ3 濃度を
８．０重量％以下に規制し、ＣａＯ／ＳｉＯ2 比を１．
４〜２．４の範囲に維持して精錬すると、生成した非金
属介在物は、Ｃｒ2 Ｏ3 濃度１０重量％以下，Ａｌ2 Ｏ
3 濃度３５重量％以下，ＭｇＯ濃度７重量％以下の組成
をもつＭｎＯ−ＳｉＯ2 系介在物となった。この非金属
介在物は、熱間加工時に粘性変形し、冷間加工時に微細
分散する特性をもっている。そのため、図１，２に中実
記号で示すように、加工割れの発生がないステンレス鋼
板が得られた。On the other hand, the Al 2 O 3 concentration in the slag is regulated to 8.0% by weight or less, and the CaO / SiO 2 ratio is set to 1.0% by weight.
When refined while maintaining the range of 4 to 2.4, the generated nonmetallic inclusions have a Cr 2 O 3 concentration of 10% by weight or less and an Al 2 O
3 MnO—SiO 2 -based inclusions having a composition of 35% by weight or less and a MgO concentration of 7% by weight or less were obtained. This nonmetallic inclusion has the property of viscous deformation during hot working and fine dispersion during cold working. Therefore, as shown by solid symbols in FIGS. 1 and 2, a stainless steel plate free from cracks was obtained.
【００１８】次いで、非金属介在物の組成に及ぼすメタ
ル組成の影響を調査した。介在物組成に影響を及ぼすメ
タル組成としては精錬時に添加する脱酸剤が挙げられ、
脱酸剤としてはＳｉ，Ａｌが使用されることから、介在
物組成に及ぼすＳｉ濃度及びＡｌ濃度の影響を調べた。
図４の調査結果にみられるように、Ａｌ濃度が０．００
３重量％より高い場合、Ｓｉ濃度の如何に拘らず加工割
れや表面疵の発生が検出された。そこで、Ａｌ濃度を
０．００３重量％以下としてＳｉ濃度を変化させたとこ
ろ、Ｓｉ／Ａｌの重量比が１００以上になると加工割れ
や表面疵が発生しなくなった。更に、ステンレス鋼の精
錬に使用される耐火物の組成が非金属介在物に及ぼす影
響を調査した。ＭｇＯ含有量が４０〜６３％で残部の主
成分がＣａＯであるドロマイト系耐火物、ＭｇＯ含有量
が５０〜８５重量％で残部の主成分がＣｒ2 Ｏ 3 であ
り、その他にＳｉＯ2 やＡｌ2 Ｏ3 を含むＭｇＯ−Ｃｒ
2 Ｏ3 系耐火物（マグクロ系）を使用し、精錬後の介在
物組成を比較調査した。Next, the influence of meta on the composition of nonmetallic inclusions
The effect of the composition of the metal was investigated. Methods that affect the composition of inclusions
A deoxidizer added at the time of refining as a tar composition,
Since Si and Al are used as deoxidizers,
The effects of Si concentration and Al concentration on the composition of the material were investigated.
As can be seen from the survey results in FIG.
If it is higher than 3% by weight, it will not be processed regardless of the Si concentration.
And the occurrence of surface flaws were detected. Therefore, the Al concentration
Changed the Si concentration to 0.003% by weight or less
When the weight ratio of Si / Al becomes 100 or more, processing cracks
And no surface flaws occurred. In addition, stainless steel
Effect of refractory composition used for smelting on nonmetallic inclusions
The sound was investigated. MgO content is 40-63% and the balance is mainly
Dolomite refractory whose component is CaO, MgO content
Is 50 to 85% by weight and the remaining main component is CrTwo O Three In
And SiOTwo And AlTwo OThree MgO-Cr containing
Two OThree Using refractory (magcro), intervening after refining
The composition of the materials was compared.
【００１９】図５の調査結果にみられるように、マグク
ロ系耐火物ではＣａＯ／ＳｉＯ2 比が大きくなると溶損
量が増加する傾向を示し、ＣａＯ／ＳｉＯ2 比が１．９
を超える付近で溶損量が増大した。溶損量の増加に伴っ
て、介在物中のＭｇＯ濃度も増加する傾向を示し、Ｃａ
Ｏ／ＳｉＯ2 比２．０以上で介在物中のＭｇＯ濃度が７
重量％を超えるようになった。ＭｇＯ濃度の上昇は、溶
損した耐火物中のＭｇＯが還元されて鋼中Ｍｇとなり、
介在物中の酸素と結び付くことに起因するものと推察さ
れる。また、マグクロ系耐火物では十分な脱硫能が得ら
れず、精錬後のＳ濃度が本発明で規定する範囲に達しな
いこともあった。As can be seen from the investigation results in FIG. 5, the magcro-based refractory tends to increase the amount of erosion when the CaO / SiO 2 ratio is increased, and the CaO / SiO 2 ratio is 1.9.
The erosion amount increased in the vicinity of exceeding. As the amount of erosion increases, the MgO concentration in inclusions also tends to increase, and Ca
O / SiO 2 ratio of 2.0 or more and MgO concentration in inclusions of 7
% By weight. The increase in MgO concentration is caused by the reduction of MgO in the eroded refractory to Mg in steel,
It is presumed to be due to binding to oxygen in inclusions. In addition, a sufficient resulphurization ability cannot be obtained with a magcro refractory, and the S concentration after refining may not reach the range specified in the present invention.
【００２０】他方、ドロマイト系耐火物を使用した場
合、ＣａＯ／ＳｉＯ2 比が高くなっても精錬時の耐火物
の溶損が少ないため、非金属介在物中のＭｇＯ濃度が７
重量％を超えることはなかった。ＭｇＯ濃度の上昇が抑
制される理由は明らかでないが、耐火物成分であるＣａ
Ｏ−ＭｇＯがスラグ成分であるＣａＯ−ＳｉＯ2 と反応
して耐火物表層部のＣａＯ／ＳｉＯ2 比が高くなり、結
果として耐火物表層部が高融点の耐火物でコーティング
された状態になることに起因するものと推察される。脱
硫に関しても、ドロマイト系耐火物を使用して精錬した
後のＳ濃度は、本発明で規定される範囲に十分収まって
いた。しかも、ドロマイト系耐火物は、マグクロ系耐火
物に比較して安価であるため、製造コストの面でも有利
である。On the other hand, when a dolomite-based refractory is used, even if the CaO / SiO 2 ratio is high, the refractory hardly dissolves during refining, so that the MgO concentration in the nonmetallic inclusion is 7%.
% By weight. It is not clear why the increase in the MgO concentration is suppressed, but the refractory component Ca
O-MgO is higher CaO / SiO 2 ratio reacts with CaO-SiO 2 is a slag component refractory surface portion, the result that the refractory surface layer portion is in a state coated with refractory material of a refractory as It is presumed to be due to Regarding desulfurization, the S concentration after refining using a dolomite-based refractory was well within the range specified in the present invention. In addition, dolomite-based refractories are inexpensive compared to magcro-based refractories, and are therefore advantageous in terms of manufacturing costs.
【００２１】実施例２：オーステナイト系ステンレス鋼
を７０トン電気炉で溶解し、転炉で製錬し、取鍋に注入
した。取鍋としては、ＭｇＯ：４０〜６３重量％，残部
ＣａＯのドロマイト系耐火物をライニングした取鍋、Ｍ
ｇＯ：５０〜８５重量％，Ｃｒ2 Ｏ3 ：７〜３０重量％
でその他にＳｉＯ2 ，Ａｌ2 Ｏ3 を含むマグクロ系耐火
物を退任具した取鍋を使用した。取鍋に収容した溶鋼を
ＶＰＤ炉で精錬し、メタル組成及びスラグ組成を変化さ
せた。精錬時、スラグ量を約４０ｋｇ／トンに維持し
た。このようにして製造されたオーステナイト系ステン
レス鋼の成分・組成を表２に示す。Example 2 Austenitic stainless steel was melted in a 70-ton electric furnace, smelted in a converter, and poured into a ladle. As a ladle, a ladle lined with dolomite-based refractories of MgO: 40 to 63% by weight and the balance CaO, M
It goes: 50~85 weight%, Cr 2 O 3: 7~30 weight%
In addition, a ladle having a resigned magcro refractory containing SiO 2 and Al 2 O 3 was used. The molten steel contained in the ladle was refined in a VPD furnace, and the metal composition and the slag composition were changed. During refining, the amount of slag was maintained at about 40 kg / ton. Table 2 shows the components and compositions of the austenitic stainless steel thus manufactured.
【００２２】 [0022]
【００２３】精錬後の溶鋼を厚み２００ｍｍ，幅１ｍの
スラブに連続鋳造した。得られたスラブを１２３０℃で
熱間圧延した後、板厚０．３ｍｍの薄板に仕上げ、更に
絞り比４の加工を施した。加工された鋼板を観察し、加
工割れの発生有無を調査した。そして、ＶＯＤ精錬後の
スラグ組成，薄板のメタル組成が絞り加工後の加工割れ
に及ぼす影響を調査した。表３の調査結果にみられるよ
うに、本発明に従った条件下で製造されたオーステナイ
ト系ステンレス鋼は、何れも加工割れが検出されず、非
金属介在物が無害化されていることが判る。これに対
し、スラグ組成やメタル組成が本発明で規定した範囲を
外れる比較例のオーステナイト系ステンレス鋼では、有
害な非金属介在物が分散しており、絞り加工後に加工割
れが発生していた。The molten steel after refining was continuously cast into a slab having a thickness of 200 mm and a width of 1 m. The obtained slab was hot-rolled at 1230 ° C., finished into a thin plate having a thickness of 0.3 mm, and further processed at a drawing ratio of 4. The processed steel plate was observed to check for occurrence of processing cracks. Then, the effects of the slag composition after VOD refining and the metal composition of the thin plate on the working crack after drawing were investigated. As can be seen from the inspection results in Table 3, no abrasion was detected in any of the austenitic stainless steels manufactured under the conditions according to the present invention, and it was found that nonmetallic inclusions were rendered harmless. . On the other hand, in the austenitic stainless steel of the comparative example in which the slag composition and the metal composition were out of the ranges specified in the present invention, harmful nonmetallic inclusions were dispersed, and processing cracks occurred after drawing.
【００２４】 [0024]
【００２５】[0025]
【発明の効果】以上に説明したように、本発明のオース
テナイト系ステンレス鋼は、非金属介在物を熱間加工時
に粘性変形し、冷間加工時に微細分散するＭｎ−ＳｉＯ
2 系に調整しているため、加工割れの起点となる非金属
介在物がなく、加工割れ感受性の低い材料であり、過酷
な加工に供される各種機能材料として使用される。ま
た、メタル組成，精錬後のスラグ組成，耐火物組成等を
調整することにより非金属介在物が組成制御されるた
め、製造自体も容易である。As described above, the austenitic stainless steel according to the present invention has a Mn-SiO that viscously deforms nonmetallic inclusions during hot working and finely disperses during cold working.
Since the system is adjusted to 2 systems, there is no non-metallic inclusions that are the starting point of work cracking, and it is a material with low work crack susceptibility, and is used as various functional materials subjected to severe working. Further, since the composition of the nonmetallic inclusions is controlled by adjusting the metal composition, the slag composition after refining, the refractory composition, and the like, the production itself is easy.
【図１】 スラグのＡｌ2 Ｏ3 濃度３．２重量％，メタ
ルのＳｉ／Ａｌ比５００の条件下でスラグのＣａＯ／Ｓ
ｉＯ2 比が介在物の組成及び加工割れに及ぼす影響を示
したグラフFIG. 1 CaO / S of slag under conditions of Al 2 O 3 concentration of slag of 3.2% by weight and metal Si / Al ratio of 500
Graph showing the effect of iO 2 ratio on the composition of inclusions and work cracking
【図２】 スラグのＡｌ2 Ｏ3 濃度８．０重量％，メタ
ルのＳｉ／Ａｌ比５００の条件下でスラグのＣａＯ／Ｓ
ｉＯ2 比が介在物の組成及び加工割れに及ぼす影響を示
したグラフFig. 2 CaO / S of slag under the conditions of Al 2 O 3 concentration of slag of 8.0% by weight and metal Si / Al ratio of 500
Graph showing the effect of iO 2 ratio on the composition of inclusions and work cracking
【図３】 スラグのＡｌ2 Ｏ3 濃度９．５重量％，メタ
ルのＳｉ／Ａｌ比５００の条件下でスラグのＣａＯ／Ｓ
ｉＯ2 比が介在物の組成及び加工割れに及ぼす影響を示
したグラフFIG. 3 CaO / S of slag under the conditions of Al 2 O 3 concentration of slag of 9.5% by weight and metal Si / Al ratio of 500.
Graph showing the effect of iO 2 ratio on the composition of inclusions and work cracking
【図４】 メタル中のＳｉ濃度及びＡｌ濃度が加工割れ
に及ぼす影響を示したグラフFIG. 4 is a graph showing the effect of Si concentration and Al concentration in metal on work cracking.
【図５】 ＣａＯ／ＳｉＯ2 比が耐火物の溶損及び介在
物中のＭｇＯ濃度に及ぼす影響を示したグラフFIG. 5 is a graph showing the effect of the CaO / SiO 2 ratio on the erosion of refractories and the MgO concentration in inclusions.
Claims (3)
〜１．０重量％，Ｍｎ：２．０重量％以下，Ｓ：０．０
０７重量％以下，Ｎｉ：８．０〜１５．０重量％，Ｃ
ｒ：１５．０〜１９．０重量％，Ｎ：０．０３重量％以
下，Ａｌ：０．００３重量％以下，残部が実質的にＦｅ
の組成を持ち、Ｓｉ／Ａｌの重量比が１００以上で、非
金属介在物の組成がＭｎＯ−ＳｉＯ2 を主成分とし、Ｍ
ｇＯ：７重量％以下，Ａｌ2 Ｏ3 ：３５重量％以下，Ｃ
ｒ2 Ｏ3 ：１０重量％以下である加工割れ感受性の低い
オーステナイト系ステンレス鋼。1. C: 0.08% by weight or less, Si: 0.2
1.0% by weight, Mn: 2.0% by weight or less, S: 0.0
07% by weight or less, Ni: 8.0 to 15.0% by weight, C
r: 15.0 to 19.0% by weight, N: 0.03% by weight or less, Al: 0.003% by weight or less, the balance being substantially Fe
, The weight ratio of Si / Al is 100 or more, the composition of the nonmetallic inclusions is mainly composed of MnO—SiO 2 ,
gO: 7% by weight or less, Al 2 O 3 : 35% by weight or less, C
r 2 O 3 : an austenitic stainless steel having a low work crack sensitivity of 10% by weight or less.
錬炉を用いて請求項１記載の組成をもつステンレス溶鋼
を精錬し、精錬終了後のスラグのＣａＯ／ＳｉＯ2 比を
１．４〜２．４に、Ａｌ2 Ｏ3 濃度を８重量％以下に維
持することを特徴とする加工割れ感受性の低いオーステ
ナイト系ステンレス鋼の製造方法。2. A stainless steel melt having the composition according to claim 1 is refined using a smelting furnace lined with a dolomite-based refractory, and the CaO / SiO 2 ratio of the slag after refining is 1.4 to 2.4. And a method for producing an austenitic stainless steel having low work cracking susceptibility, wherein the concentration of Al 2 O 3 is maintained at 8% by weight or less.
３４〜５７重量％を含む組成のドロマイト系耐火物を使
用する請求項２記載の加工割れ感受性の低いオーステナ
イト系ステンレス鋼の製造方法。3. MgO: 40-63% by weight and CaO:
The method for producing an austenitic stainless steel having low susceptibility to work cracking according to claim 2, wherein a dolomite-based refractory having a composition containing 34 to 57% by weight is used.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03902797A JP3865853B2 (en) | 1997-02-24 | 1997-02-24 | Austenitic stainless steel with low work cracking susceptibility and method for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03902797A JP3865853B2 (en) | 1997-02-24 | 1997-02-24 | Austenitic stainless steel with low work cracking susceptibility and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10237598A true JPH10237598A (en) | 1998-09-08 |
| JP3865853B2 JP3865853B2 (en) | 2007-01-10 |
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ID=12541638
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|---|---|---|---|
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| Country | Link |
|---|---|
| JP (1) | JP3865853B2 (en) |
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| JP6359783B1 (en) * | 2017-11-17 | 2018-07-18 | 日新製鋼株式会社 | Austenitic stainless steel sheet and manufacturing method thereof |
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| Publication number | Publication date |
|---|---|
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