JP2006183129A - Austenitic-ferritic stainless steel having excellent formability - Google Patents
Austenitic-ferritic stainless steel having excellent formability Download PDFInfo
- Publication number
- JP2006183129A JP2006183129A JP2005023492A JP2005023492A JP2006183129A JP 2006183129 A JP2006183129 A JP 2006183129A JP 2005023492 A JP2005023492 A JP 2005023492A JP 2005023492 A JP2005023492 A JP 2005023492A JP 2006183129 A JP2006183129 A JP 2006183129A
- Authority
- JP
- Japan
- Prior art keywords
- mass
- less
- austenite phase
- stainless steel
- austenitic
- 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
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 46
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 99
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 48
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 43
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims description 14
- 239000010935 stainless steel Substances 0.000 claims description 12
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 239000012535 impurity Substances 0.000 abstract description 3
- 229910000831 Steel Inorganic materials 0.000 description 30
- 239000010959 steel Substances 0.000 description 30
- 230000007797 corrosion Effects 0.000 description 18
- 238000005260 corrosion Methods 0.000 description 18
- 239000011651 chromium Substances 0.000 description 17
- 229910000734 martensite Inorganic materials 0.000 description 15
- 230000000694 effects Effects 0.000 description 12
- 238000000137 annealing Methods 0.000 description 11
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 11
- 238000012545 processing Methods 0.000 description 10
- 238000004458 analytical method Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 230000009466 transformation Effects 0.000 description 6
- 238000005336 cracking Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 229910052761 rare earth metal Inorganic materials 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 5
- 238000009864 tensile test Methods 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 4
- 238000004453 electron probe microanalysis Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 238000005097 cold rolling Methods 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 206010070834 Sensitisation Diseases 0.000 description 2
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 2
- 239000008280 blood Substances 0.000 description 2
- 210000004369 blood Anatomy 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000010191 image analysis Methods 0.000 description 2
- 238000013507 mapping Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- -1 potassium ferricyanide Chemical compound 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 230000008313 sensitization Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 241001091538 Dimorphandra Group A Species 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- CXOWYMLTGOFURZ-UHFFFAOYSA-N azanylidynechromium Chemical compound [Cr]#N CXOWYMLTGOFURZ-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- GVEHJMMRQRRJPM-UHFFFAOYSA-N chromium(2+);methanidylidynechromium Chemical compound [Cr+2].[Cr]#[C-].[Cr]#[C-] GVEHJMMRQRRJPM-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910001105 martensitic stainless steel Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 229910003470 tongbaite Inorganic materials 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Images
Landscapes
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
本発明は、成形性に優れたオーステナイト・フェライト系ステンレス鋼に関するものである。 The present invention relates to an austenitic ferritic stainless steel having excellent formability.
ステンレス鋼は、耐食性に優れた材料として、自動車用部材や建築用部材、厨房機器等の広い分野で用いられている。ステンレス鋼は、鋼が有する組織から一般に、オーステナイト系、フェライト系、オーステナイト・フェライト系およびマルテンサイト系の４つに分類されている。このうち、ＳＵＳ３０４に代表されるオーステナイト系ステンレス鋼は、耐食性に優れると共に、加工性にも優れているため、最も一般的に用いられている。 Stainless steel is used as a material having excellent corrosion resistance in a wide range of fields such as automobile members, building members, and kitchen equipment. Stainless steels are generally classified into four types: austenitic, ferritic, austenitic / ferritic, and martensitic based on the structure of the steel. Among these, austenitic stainless steel represented by SUS304 is most commonly used because it has excellent corrosion resistance and workability.
しかしながら、オーステナイト系ステンレス鋼は、他のステンレス鋼に比べて高い加工性を有するものの、高価なNiを多量に含有しているため、価格が高いという問題がある。また、オーステナイト系ステンレス鋼は、成形限界近傍まで加工すると置き割れを起こし易いことや、応力腐食割れ(Stress Corrosion Cracking：ＳＣＣ)に対する感受性が高いことのため、燃料タンクのように、安全性に対する要求が極めて高い部位に適用するには問題があった。また、マルテンサイト系ステンレス鋼は、強度は優れるものの、延性や張出成形性および耐食性に劣り、加工用途には適用できない。 However, although austenitic stainless steel has high workability compared to other stainless steels, it has a problem of high price because it contains a large amount of expensive Ni. In addition, austenitic stainless steel is prone to cracking when processed to near the forming limit and is highly sensitive to stress corrosion cracking (SCC). However, there was a problem in applying to a site with extremely high. In addition, martensitic stainless steel has excellent strength but is inferior in ductility, stretch formability and corrosion resistance, and cannot be applied to processing applications.
一方、フェライト系ステンレス鋼は、Crの含有量を増加させることで、耐食性を向上させることが可能であり、また、置き割れや応力腐食割れを起こし難いという優れた特性を有する。しかし、フェライト系ステンレス鋼は、オーステナイト系ステンレス鋼と比較して加工性、特に強度−延性バランスに劣るという欠点がある。 On the other hand, ferritic stainless steel can improve corrosion resistance by increasing the Cr content, and has excellent characteristics that it is difficult to cause cracking and stress corrosion cracking. However, ferritic stainless steel has a disadvantage that it is inferior in workability, particularly strength-ductility balance, compared to austenitic stainless steel.
そこで、フェライト系ステンレス鋼の加工性を改善する技術が提案されている。例えば、特許文献１には、Crを５〜60wt％含有したフェライト系ステンレス鋼板において、ＣおよびＮ含有量を低減すると共に、Ti，Nbを適量添加した深絞り成形性に優れるクロム鋼板とその製造方法が開示されている。しかし、特許文献１の鋼板は、深絞り性を改善するために、鋼中のＣおよびＮ含有量をそれぞれＣ：0.03wt％以下、Ｎ：0.02wt％以下に低減しているため、鋼板強度が低くしかも延性の改善も不十分である、つまり、強度−延性バランスに劣るという問題がある。そのため、特許文献１の鋼板を自動車部材に適用した場合には、部材に対する要求強度を得るのに必要な板厚が厚くなり、軽量化に寄与できない他、張出し成形や深絞り成形、液圧成形等の厳しい加工用途には適用できないという問題があった。 Therefore, a technique for improving the workability of ferritic stainless steel has been proposed. For example, Patent Document 1 discloses a chromium steel sheet that is excellent in deep drawing formability by reducing the C and N contents and adding appropriate amounts of Ti and Nb in a ferritic stainless steel sheet containing 5 to 60 wt% Cr. A method is disclosed. However, in the steel sheet of Patent Document 1, the C and N contents in the steel are reduced to C: 0.03 wt% or less and N: 0.02 wt% or less, respectively, in order to improve deep drawability. However, the improvement of ductility is also insufficient, that is, the strength-ductility balance is inferior. Therefore, when the steel plate of Patent Document 1 is applied to an automobile member, the plate thickness necessary to obtain the required strength for the member is increased, and it cannot contribute to weight reduction. In addition, overhang forming, deep drawing forming, hydraulic forming There is a problem that it cannot be applied to severe processing applications such as.
そこで、上記オーステナイト系とフェライト系の中間に位置するオーステナイト・フェライト系ステンレス鋼板が、近年、注目されている。このオーステナイト・フェライト系ステンレス鋼板は、耐食性に優れているが、Ni含有量が４mass％以上と高いため、価格が依然として高価であるという問題がある。 Thus, in recent years, an austenitic / ferritic stainless steel sheet located between the austenitic and ferritic alloys has attracted attention. This austenitic ferritic stainless steel sheet is excellent in corrosion resistance, but has a problem that the price is still expensive because the Ni content is as high as 4 mass% or more.
この問題に対応するものとして、特許文献２に、Ni添加量を0.1％超１％未満に制限した上で、さらにオーステナイト安定性指数(ＩＭ指数：551−805(Ｃ＋Ｎ)％−8.52Si％−8.57Mn％−12.51Cr％−36.02Ni％−34.52Cu％−13.96Mo％)を40〜115の範囲に制御することにより、引張り延びに優れるオーステナイト・フェライト系ステンレス鋼板が開示されている。
しかしながら、上記特許文献２に開示されたオーステナイト・フェライト系ステンレス鋼板は、延性が向上しているとはいえまだ不十分であり、また、深絞り性も十分なものではなかった。従って、極度の張出し成形や液圧成形が施される用途への適用は依然として難しく、また、極度の深絞り成形が施される用途への適用も困難であるという問題があった。 However, the austenitic ferritic stainless steel sheet disclosed in Patent Document 2 is still insufficient even though the ductility is improved, and the deep drawability is not sufficient. Therefore, there is a problem that it is still difficult to apply to applications where extreme stretch molding or hydraulic molding is performed, and it is difficult to apply to applications where extreme deep drawing is performed.
本発明の目的は、従来技術が抱える上記問題点を解決し、延性および深絞り性に優れた高い成形性を有するオーステナイト・フェライト系ステンレス鋼を提供することにある。 An object of the present invention is to provide the austenitic ferritic stainless steel having high formability that is excellent in ductility and deep drawability by solving the above-mentioned problems of the prior art.
発明者らは、オーステナイト・フェライト系ステンレス鋼の成形性を改善するために、各種の成分および組織を有するステンレス鋼について、成形性の評価を行った。その結果、オーステナイト・フェライト系ステンレス鋼において、特に高い成形性を有する場合があることを見出した。そして、この原因についてさらに検討を進めた結果、Niを１〜３mass％含有したオーステナイト・フェライト系ステンレス鋼中では、オーステナイト相の体積分率とそのオーステナイト相内に固溶しているＣおよびＮの合計量が成形性に大きく影響していることを見出し、本発明を完成させた。 Inventors evaluated moldability about the stainless steel which has various components and structure | tissues, in order to improve the moldability of an austenitic ferritic stainless steel. As a result, it has been found that austenite-ferritic stainless steel may have particularly high formability. As a result of further investigation on this cause, in the austenitic ferritic stainless steel containing 1 to 3 mass% of Ni, the volume fraction of the austenite phase and the C and N dissolved in the austenite phase are included. It was found that the total amount has a great influence on the moldability, and the present invention was completed.
上記知見に基く本発明は、Ｃ：0.2mass％以下、Si:４mass％以下、Mn：10mass％以下、Ｐ：0.1mass％以下、Ｓ：0.03mass％以下、Cr：15〜35mass％、Ni：１〜３mass％、Ｎ：0.05〜0.6mass％を含有し、残部がFeおよび不可避的不純物からなり、フェライト相とオーステナイト相を含むステンレス鋼であって、上記オーステナイト相中のＣとＮの合計量が0.16〜２mass％、該オーステナイト相の体積分率が10〜85％であることを特徴とする成形性に優れるオーステナイト・フェライト系ステンレス鋼である。 The present invention based on the above knowledge is C: 0.2 mass% or less, Si: 4 mass% or less, Mn: 10 mass% or less, P: 0.1 mass% or less, S: 0.03 mass% or less, Cr: 15 to 35 mass%, Ni: 1 to 3 mass%, N: 0.05 to 0.6 mass%, with the balance being Fe and inevitable impurities, a stainless steel containing a ferrite phase and an austenite phase, the total amount of C and N in the austenite phase Is an austenitic-ferritic stainless steel with excellent formability, characterized by 0.16-2 mass% and a volume fraction of the austenite phase of 10-85%.
また、本発明のステンレス鋼は、上記成分組成に加えてさらに、下記Ａ〜Ｄ群のうちから選ばれる少なくとも１以上の成分を含有することを特徴とする。
記
Ａ群 Ｖ：0.5mass％以下
Ｂ群 Al：0.1mass％以下
Ｃ群 Mo:４mass％以下、Cu：４mass％以下のいずれか１種または２種
Ｄ群 Ｂ:0.01mass％以下、Ca：0.01mass％以下、Mg：0.01mass％以下、REM：0.1mass％以下のいずれか１種または２種以上
In addition to the above component composition, the stainless steel of the present invention further includes at least one component selected from the following groups A to D.
Group A V: 0.5 mass% or less B group Al: 0.1 mass% or less C group Mo: 4 mass% or less, Cu: 4 mass% or less One or two types D group B: 0.01 mass% or less, Ca: 0.01 Any one or more of mass% or less, Mg: 0.01 mass% or less, REM: 0.1 mass% or less
なお、本発明の上記ステンレス鋼は、下記式で定義される加工誘起マルテンサイト指数(Ｍd(γ))を−30〜90とすれば、より優れた加工性を得ることができる。
記
Ｍd(γ)＝551−462(Ｃ(γ)＋Ｎ(γ))−9.2Si(γ)−8.1Mn(γ)−13.7Cr(γ)−29Ni(γ)−29Cu(γ)−18.5Mo(γ)
ただし、Ｃ(γ)、Ｎ(γ)、Si(γ)、Mn(γ)、Cr(γ)、Ni(γ)、Cu(γ)およびMo(γ)は、それぞれオーステナイト相中のＣ量(mass％)、Ｎ量(mass％)、Si量(mass％)、Mn量(mass％)、Cr量(mass％)、Ni量(mass％)、Cu量(mass％)、Mo量(mass％)
In addition, the said stainless steel of this invention can obtain the more outstanding workability, if the process induction martensite index (Md ((gamma))) defined by a following formula shall be -30-90.
Md (γ) = 551−462 (C (γ) + N (γ)) − 9.2Si (γ) −8.1Mn (γ) −13.7Cr (γ) −29Ni (γ) −29Cu (γ) −18.5Mo (γ)
However, C (γ), N (γ), Si (γ), Mn (γ), Cr (γ), Ni (γ), Cu (γ) and Mo (γ) are the amounts of C in the austenite phase, respectively. (mass%), N amount (mass%), Si amount (mass%), Mn amount (mass%), Cr amount (mass%), Ni amount (mass%), Cu amount (mass%), Mo amount ( mass%)
本発明によれば、高価なNiを多量に含有することもなく、延性および深絞り性に優れた高い成形性を有するオーステナイト・フェライト系ステンレス鋼を安価に提供することができる。 According to the present invention, austenite-ferritic stainless steel having high formability excellent in ductility and deep drawability can be provided at low cost without containing a large amount of expensive Ni.
本発明に係るオーステナイト・フェライト系ステンレス鋼について説明する。
本発明のステンレス鋼は、Niを１〜３mass％含有した主としてオーステナイト相とフェライト相からなるオーステナイト・フェライト系ステンレス鋼であることが必要である。すなわち、本発明は、Niを１〜３mass％含有した主としてオーステナイト・フェライト系ステンレス鋼において、オーステナイト相の体積分率と、このオーステナイト相中に含まれるＣとＮの合計量がプレス成形性に大きな影響を与えることを見出したところに特徴がある。
The austenitic ferritic stainless steel according to the present invention will be described.
The stainless steel of the present invention is required to be an austenitic / ferritic stainless steel mainly containing an austenite phase and a ferrite phase containing 1 to 3 mass% of Ni. That is, in the present invention, mainly in austenitic / ferritic stainless steel containing 1 to 3 mass% of Ni, the volume fraction of the austenite phase and the total amount of C and N contained in the austenite phase are large in press formability. It is characterized by finding out that it has an effect.
上記オーステナイト相の体積分率は、鋼の全組織に対して体積率で10〜85％であることが必要である。オーステナイト相の体積分率が10％未満では、高い成形性が得られない。また85％を超えると、オーステナイト系ステンレス鋼特有の現象であるＳＣＣ割れが散見されるようになるからである。好ましいオーステナイト相の体積分率の範囲は、15〜80％である。 The volume fraction of the austenite phase needs to be 10 to 85% by volume with respect to the entire structure of the steel. If the volume fraction of the austenite phase is less than 10%, high formability cannot be obtained. Further, if it exceeds 85%, SCC cracks, a phenomenon peculiar to austenitic stainless steel, will be observed. A preferred austenite phase volume fraction range is 15-80%.
上記オーステナイト相の体積分率は、鋼の成分組成と焼鈍条件(温度、時間)を調整することによって制御することができる。具体的には、Cr量が低く、Ｃ，Ｎ量が高いほど、オーステナイト相の体積分率は増加する。また、焼鈍温度は、高過ぎるとオーステナイト相の体積分率が減少し、逆に、低過ぎるとＣ，Ｎが析出するため、やはりオーステナイト相の体積分率が減少する。従って、鋼成分に応じて、最大のオーステナイト相の体積分率が得られる温度範囲があり、本発明の成分組成では、その温度範囲は950〜1300℃である。焼鈍時間は、長い程、鋼の成分組成と温度によって決定される平衡状態のオーステナイト相の体積分率に近づくが、30秒程度であれば十分である。 The volume fraction of the austenite phase can be controlled by adjusting the composition of steel and the annealing conditions (temperature, time). Specifically, the volume fraction of the austenite phase increases as the Cr content is lower and the C and N content is higher. On the other hand, if the annealing temperature is too high, the volume fraction of the austenite phase decreases. On the other hand, if the annealing temperature is too low, C and N precipitate, so the volume fraction of the austenite phase also decreases. Therefore, there is a temperature range in which the maximum volume fraction of the austenite phase can be obtained depending on the steel component. In the composition of the present invention, the temperature range is 950 to 1300 ° C. The longer the annealing time is, the closer to the volume fraction of the austenite phase in an equilibrium state determined by the composition and temperature of the steel, but about 30 seconds is sufficient.
また、本発明のステンレス鋼においては、オーステナイト相中に含まれるＣとＮの合計量は0.16〜２mass％であることが必要である。オーステナイト相中のＣとＮの合計量が、0.16mass％未満では十分な成形性が得られない。一方、ＣとＮの合計量が２mass％超え含有すると、焼鈍後の冷却時に炭化物、窒化物が多量に析出し、延性にはむしろ悪影響を及ぼすからである。なお、ＣとＮの合計量は、好ましくは0.2〜２mass％、さらに好ましくは0.3〜1.5mass％の範囲である。 In the stainless steel of the present invention, the total amount of C and N contained in the austenite phase needs to be 0.16 to 2 mass%. If the total amount of C and N in the austenite phase is less than 0.16 mass%, sufficient formability cannot be obtained. On the other hand, if the total amount of C and N exceeds 2 mass%, a large amount of carbides and nitrides precipitate during cooling after annealing, and rather adversely affects the ductility. The total amount of C and N is preferably in the range of 0.2 to 2 mass%, more preferably 0.3 to 1.5 mass%.
上記オーステナイト相中のＣ，Ｎ量の制御は、鋼の成分組成と焼鈍条件(温度、時間)を調整することによって行うことができる。すなわち、鋼中のＣ，Ｎ量が多いとオーステナイト中のＣ，Ｎ量も増加する。また、鋼の成分組成が同一の場合は、焼鈍条件によって決定されたオーステナイト相の体積分率が低いほど、オーステナイト相中にＣ，Ｎを濃化させることができる。なお、オーステナイト相中のＣ，Ｎの測定は、ＥＰＭＡにより測定することができる。 The amount of C and N in the austenite phase can be controlled by adjusting the composition of steel and the annealing conditions (temperature and time). That is, when the amount of C and N in steel is large, the amount of C and N in austenite also increases. Moreover, when the component composition of steel is the same, C and N can be concentrated in an austenite phase, so that the volume fraction of the austenite phase determined by annealing conditions is low. In addition, the measurement of C and N in an austenite phase can be measured by EPMA.
オーステナイト相の体積分率およびオーステナイト相中に含まれるＣとＮの合計量が、鋼の成形性に大きな影響を及ぼす理由について、まだ十分明らかとはなっていないが、発明者らは、以下のように考えている。
すなわち、Ｃ，Ｎ，Ni，Mnは、オーステナイト相生成元素、Cr，Siはフェライト相生成元素と考えられており、それらの元素は各相に濃化する傾向がある。中でもＣとＮは、鋼中の含有量および熱処理条件により、オーステナイト相への濃化度が顕著に変化する。また、オーステナイト相は、成形性と関係しており、オーステナイト相の体積分率が高いほど成形性は良好となる。
The reason why the volume fraction of the austenite phase and the total amount of C and N contained in the austenite phase have a great influence on the formability of the steel has not been clarified yet. I think so.
That is, C, N, Ni, and Mn are considered to be austenite phase forming elements, and Cr and Si are considered to be ferrite phase forming elements, and these elements tend to concentrate in each phase. Among these, C and N have a remarkable change in the concentration to the austenite phase depending on the content in the steel and the heat treatment conditions. The austenite phase is related to moldability, and the higher the volume fraction of the austenite phase, the better the moldability.
その理由は、鋼は、引張変形を受けると、均一変形を経た後、局部的にネッキング(くびれ)が生じて、やがて破断に至るのが一般的であるが、本発明のステンレス鋼は、オーステナイト相が存在するため、微小なネッキングが生じ始めると、その部位のオーステナイト相がマルテンサイト相に加工誘起変態し、他の部位に比べて硬くなるため、その部位のネッキングがそれ以上進まなくなり、代わりに他の部位の変形が進行する結果、鋼全体が均一に変形して高い延性が得られるからである。 The reason for this is that when steel is subjected to tensile deformation, it generally undergoes uniform deformation, and then locally necking (necking) occurs and eventually breaks, but the stainless steel of the present invention is austenitic. When a minute necking begins to occur due to the presence of a phase, the austenite phase at that site undergoes processing-induced transformation to the martensite phase and becomes harder than other sites, so that the necking at that site does not progress further, instead This is because, as a result of the progress of deformation of other parts, the entire steel is uniformly deformed and high ductility is obtained.
そこで、鋼組成や熱処理条件を調整し、オーステナイト相の体積分率を高めるとともに、オーステナイト相中のＣとＮの合計量を高めてやれば、オーステナイト相が安定化し、加工を受けたときに加工誘起変態を適度に起こして、延性向上効果が効果的に発現し、優れた加工性を得ることができる。そのためには、オーステナイト相の体積分率が10％以上で、オーステナイト相中のＣとＮの合計量が0.16mass％以上であることが必要となる。一方、オーステナイト相中のＣとＮの合計量が0.16mass％未満では、オーステナイト相が不安定化し、加工時にオーステナイト相の多くがマルテンサイト相に変態して延性が低下するため、オーステナイト相の体積分率をいくら高めても、プレス成形性は向上しない。また、オーステナイト相の体積分率を85％以下に制限する理由は、85％を超えると、ＳＣＣ感受性が高まるため好ましくないからである。 Therefore, by adjusting the steel composition and heat treatment conditions to increase the volume fraction of the austenite phase and increase the total amount of C and N in the austenite phase, the austenite phase is stabilized and processed when subjected to processing. The induced transformation is appropriately caused, and the effect of improving ductility is effectively exhibited, and excellent workability can be obtained. For that purpose, it is necessary that the volume fraction of the austenite phase is 10% or more and the total amount of C and N in the austenite phase is 0.16 mass% or more. On the other hand, if the total amount of C and N in the austenite phase is less than 0.16 mass%, the austenite phase becomes unstable and most of the austenite phase transforms into a martensite phase during processing, resulting in a decrease in ductility. No matter how much the fraction is increased, the press formability is not improved. The reason why the volume fraction of the austenite phase is limited to 85% or less is that if it exceeds 85%, the SCC sensitivity increases, which is not preferable.
さらに、発明者らは、本発明のオーステナイト・フェライト系ステンレス鋼は、オーステナイト相中のＣ，Ｎ，Si，Mn，Cr，Ni，Cu，Mo含有量から下記式；
Ｍd(γ)＝551−462(Ｃ(γ)＋Ｎ(γ))−9.2Si(γ)−8.1Mn(γ)−13.7Cr(γ)−29Ni(γ)−29Cu(γ)−18.5Mo(γ)
ただし、Ｃ(γ)、Ｎ(γ)、Si(γ)、Mn(γ)、Cr(γ)、Ni(γ)、Cu(γ)およびMo(γ)は、それぞれオーステナイト相中のＣ量(mass％)、Ｎ量(mass％)、Si量(mass％)、Mn量(mass％)、Cr量(mass％)、Ni量(mass％)、Cu量(mass％)、Mo量(mass％)
で定義されるオーステナイト相の加工誘起マルテンサイト指数(Ｍd(γ))を−30〜90の範囲に制御することにより、更に高い延性特性が得ることができる、具体的には、板厚0.8mmでも48％以上の全伸びが得られることを見出した。
Furthermore, the inventors have determined that the austenitic ferritic stainless steel of the present invention has the following formula from the contents of C, N, Si, Mn, Cr, Ni, Cu, and Mo in the austenitic phase:
Md (γ) = 551−462 (C (γ) + N (γ)) − 9.2Si (γ) −8.1Mn (γ) −13.7Cr (γ) −29Ni (γ) −29Cu (γ) −18.5Mo ( γ)
However, C (γ), N (γ), Si (γ), Mn (γ), Cr (γ), Ni (γ), Cu (γ) and Mo (γ) are the amounts of C in the austenite phase, respectively. (mass%), N amount (mass%), Si amount (mass%), Mn amount (mass%), Cr amount (mass%), Ni amount (mass%), Cu amount (mass%), Mo amount ( mass%)
By controlling the work-induced martensite index (Md (γ)) of the austenite phase defined by -30 to 90, higher ductility characteristics can be obtained. Specifically, the thickness is 0.8 mm. However, they found that a total elongation of 48% or more was obtained.
上記Ｍd(γ)は、オーステナイト相が加工を受けた際の加工誘起マルテンサイト変態のし易さを示す指数であり、この指数が高いほど、加工に伴うマルテンサイト変態が起こり易いことを意味する。そして、上記Ｍd(γ)が−30〜90の範囲が好ましい理由は、−30未満の場合には、加工誘起マルテンサイト変態が起こり難いため、微小なネッキングが生じ始めるときに、微小ネッキング部で発生する加工誘起マルテンサイト量が少ないからであり、また、Ｍd(γ)が90を超える場合には、微小なネッキングが生じ始める前に鋼全体でオーステナイト相がマルテンサイト変態してしまうため、微小なネッキングが生じ始めるときには、加工誘起マルテンサイトのもととなるオーステナイト相が少なくなるからである。従って、Ｍd(γ)を−30〜90の範囲に制御した場合にのみ、微小ネッキングが生じ始めた時に、ネッキング部位での発生するマルテンサイト量が最適化されて、非常に高い延性を示すものと考えられる。 The above Md (γ) is an index indicating the ease of processing-induced martensitic transformation when the austenite phase is processed. The higher this index is, the easier the martensitic transformation associated with processing occurs. . The reason why the above Md (γ) is preferably in the range of −30 to 90 is that when it is less than −30, the processing-induced martensite transformation hardly occurs. This is because the amount of work-induced martensite generated is small, and when Md (γ) exceeds 90, the austenite phase undergoes martensitic transformation throughout the steel before micronecking begins to occur. This is because when a large amount of necking begins to occur, the austenite phase that becomes the basis of the processing-induced martensite decreases. Therefore, only when Md (γ) is controlled in the range of −30 to 90, when the minute necking begins to occur, the amount of martensite generated at the necking site is optimized and exhibits very high ductility. it is conceivable that.
次に、本発明に係るオーステナイト・フェライト系ステンレス鋼の成分組成を限定する理由について説明する。
Ｃ：0.2mass％以下
Ｃは、オーステナイト相の体積分率を高めると共に、オーステナイト相中に濃化してオーステナイト相の安定度を高める重要な元素である。上記効果を得るためには、0.003mass％以上含有することが好ましい。しかし、Ｃ量が、0.2mass％を超えると、Ｃを固溶させるための熱処理温度が著しく高くなり、生産性が低下する。そのため、Ｃ量は0.2mass％以下に制限する。好ましくは0.15mass％未満である。さらに、耐応力腐食割れ性を改善する観点からは、Ｃは0.10mass％未満であることがより好ましい。
Next, the reason for limiting the component composition of the austenitic ferritic stainless steel according to the present invention will be described.
C: 0.2 mass% or less C is an important element that increases the volume fraction of the austenite phase and concentrates in the austenite phase to increase the stability of the austenite phase. In order to acquire the said effect, it is preferable to contain 0.003 mass% or more. However, when the amount of C exceeds 0.2 mass%, the heat treatment temperature for dissolving C is extremely high, and the productivity is lowered. Therefore, the amount of C is limited to 0.2 mass% or less. Preferably it is less than 0.15 mass%. Further, from the viewpoint of improving the stress corrosion cracking resistance, C is more preferably less than 0.10 mass%.
Si：４mass％以下
Siは、脱酸剤として添加される元素であり、0.01mass％以上含有することが好ましい。しかし、Siの添加量が４mass％を超えると、鋼材強度が高くなって冷間加工性を劣化させるため、４mass％以下とする。好ましくは1.2mass％以下である。さらに、鋭敏化による耐食性の劣化を防止する観点からは、Si量は0.4mass％以下に制限するのがより好ましい。
Si: 4 mass% or less
Si is an element added as a deoxidizer, and is preferably contained in an amount of 0.01 mass% or more. However, if the addition amount of Si exceeds 4 mass%, the steel material strength increases and the cold workability deteriorates, so the amount is set to 4 mass% or less. Preferably it is 1.2 mass% or less. Furthermore, from the viewpoint of preventing deterioration of corrosion resistance due to sensitization, the Si content is more preferably limited to 0.4 mass% or less.
Mn：10mass％以下
Mnは、脱酸剤として、また、オーステナイト相のＭd(γ)調整用元素として有効な元素であり、適宜添加することができる。上記効果を得るためには、0.01mass％以上含有することが好ましい。しかし、添加量が10mass％を超えると熱間加工性が劣化するため、10mass％以下とする。好ましくは７mass％以下である。
Mn: 10 mass% or less
Mn is an effective element as a deoxidizer and as an element for adjusting Md (γ) of the austenite phase, and can be added as appropriate. In order to acquire the said effect, it is preferable to contain 0.01 mass% or more. However, if the added amount exceeds 10 mass%, the hot workability deteriorates, so it is set to 10 mass% or less. Preferably it is 7 mass% or less.
Ｐ：0.1mass％以下
Ｐは、熱間加工性に有害な元素であり、特に、0.1mass％を超えると悪影響が顕著となるので0.1mass％以下とする。好ましくは、0.05mass％以下である。
P: 0.1 mass% or less P is an element harmful to hot workability. In particular, if it exceeds 0.1 mass%, the adverse effect becomes significant, so 0.1 mass% or less. Preferably, it is 0.05 mass% or less.
Ｓ：0.03mass％以下
Ｓは、熱間加工性に有害な元素であり、特に、0.03mass％を超えると悪影響が顕著となるので0.03mass％以下とする。好ましくは、0.02mass％以下である。
S: 0.03 mass% or less S is an element harmful to hot workability. In particular, if it exceeds 0.03 mass%, the adverse effect becomes significant, so 0.03 mass% or less. Preferably, it is 0.02 mass% or less.
Cr：15〜35mass％
Crは、ステンレス鋼に耐食性を付与する最も重要な成分であり、15mass％未満では、十分な耐食性が得られない。一方、Crは、フェライト安定化元素であり、その量が35mass％を超えると、鋼中にオーステナイト相を形成することが困難となる。よって、Crは、15〜35mass％に制限する必要がある。好ましくは17〜30mass％、さらに好ましくは18〜28mass％の範囲である。
Cr: 15-35mass%
Cr is the most important component for imparting corrosion resistance to stainless steel, and if it is less than 15 mass%, sufficient corrosion resistance cannot be obtained. On the other hand, Cr is a ferrite stabilizing element. If the amount exceeds 35 mass%, it becomes difficult to form an austenite phase in the steel. Therefore, Cr needs to be limited to 15 to 35 mass%. Preferably it is 17-30 mass%, More preferably, it is the range of 18-28 mass%.
Ni：１〜３mass％
Niは、オーステナイト生成元素であり、耐隙間腐食性向上のためには１mass％以上が必要である。しかし、３mass％を超えるとフェライト相中のNi量が増加してフェライト相の延性が劣化し、成形性の低下を招くので、３mass％以下に制限する。好ましくは１〜２mass％である。
Ni: 1-3 mass%
Ni is an austenite-forming element and needs to be 1 mass% or more for improving crevice corrosion resistance. However, if it exceeds 3 mass%, the amount of Ni in the ferrite phase increases and the ductility of the ferrite phase deteriorates, resulting in a decrease in formability, so it is limited to 3 mass% or less. Preferably it is 1-2 mass%.
Ｎ：0.05〜0.6mass％
Ｎは、Ｃと同様にオーステナイト相の体積分率を高めると共に、オーステナイト相中に濃化し、オーステナイトを安定化する元素である。しかし、Ｎが0.6mass％を超えると、鋳造時にブローホールを発生するようになる。また0.05mass％未満では、オーステナイト相中のＮの濃化が不十分となる。よって、0.05〜0.6mass％の範囲とする。なお、Ｎの含有量は、好ましくは0.1〜0.4mass％である。さらに、Ｎは、オーステナイト相生成の観点からは0.18mass％以上、熱間加工性の観点からは0.34mass％以下であることが好ましい。
N: 0.05-0.6mass%
N, like C, is an element that increases the volume fraction of the austenite phase and concentrates in the austenite phase to stabilize the austenite. However, when N exceeds 0.6 mass%, blow holes are generated during casting. If it is less than 0.05 mass%, the concentration of N in the austenite phase becomes insufficient. Therefore, it is set as the range of 0.05-0.6 mass%. The N content is preferably 0.1 to 0.4 mass%. Furthermore, N is preferably 0.18 mass% or more from the viewpoint of austenite phase generation and 0.34 mass% or less from the viewpoint of hot workability.
本発明のステンレス鋼は、上記の必須とする成分以外に、下記の成分を必要に応じて含有してもよい。 The stainless steel of the present invention may contain the following components as necessary in addition to the essential components.
Ｖ：0.5mass％以下
Ｖは、鋼の組織を微細化し、強度を高める元素であり、要求特性に応じて、0.005mass％以上添加することが好ましい。ただし、0.5mass％を超えると、Ｃおよび／またはＮを固溶させるための熱処理温度が著しく高くなり、生産性の低下を招く。そのため、Ｖの添加量は0.5mass％以下に制限するのが好ましい。より好ましくは0.2mass％以下である。
V: 0.5 mass% or less V is an element that refines the structure of steel and increases strength, and is preferably added in an amount of 0.005 mass% or more depending on required characteristics. However, when it exceeds 0.5 mass%, the heat treatment temperature for dissolving C and / or N is remarkably increased, leading to a decrease in productivity. Therefore, it is preferable to limit the addition amount of V to 0.5 mass% or less. More preferably, it is 0.2 mass% or less.
Al：0.1mass％以下
Alは、強力な脱酸剤であり、脱酸元素として添加する場合は、0.003mass％以上とすることが好ましい。ただし、0.1mass％を超えると、窒化物を形成して表面疵の原因となるので、0.1mass％以下に制限するのが好ましい。より好ましくは0.02mass％以下である。
Al: 0.1 mass% or less
Al is a strong deoxidizing agent, and when added as a deoxidizing element, it is preferable to set it to 0.003 mass% or more. However, if it exceeds 0.1 mass%, a nitride is formed and causes surface defects. Therefore, it is preferably limited to 0.1 mass% or less. More preferably, it is 0.02 mass% or less.
Mo:４mass％以下、Cu：４mass％以下のいずれか１種または２種
Moは、耐食性を向上させるために適宜添加することができ、その効果を得るには、0.1mass％以上添加することが好ましい。しかし、４mass％を超えると効果が飽和するので、４mass％以下に制限するのが好ましい。より好ましくは２mass％以下である。同様に、Cuは、耐食性を向上させるために適宜添加することができるので、添加する場合には0.1mass％以上であることが好ましい。しかし、４mass％を超えると熱間加工性が劣化するので、４mass％以下に制限するのが好ましい。より好ましくは２mass％以下である。
Any one or two of Mo: 4 mass% or less, Cu: 4 mass% or less
Mo can be added as appropriate in order to improve the corrosion resistance. To obtain the effect, it is preferable to add 0.1 mass% or more. However, since the effect is saturated when it exceeds 4 mass%, it is preferable to limit it to 4 mass% or less. More preferably, it is 2 mass% or less. Similarly, since Cu can be added as appropriate in order to improve the corrosion resistance, when added, it is preferably 0.1 mass% or more. However, since hot workability will deteriorate when it exceeds 4 mass%, it is preferable to restrict to 4 mass% or less. More preferably, it is 2 mass% or less.
Ｂ：0.01mass％以下、Ca：0.01mass％以下、Mg：0.01mass％以下、REM：0.1mass％以下のうちのいずれか１種または２種以上
Ｂ，Ca，Mgは、熱間加工性を向上させる成分であり、適宜添加することができる。その効果を得るためには0.0003mass％以上添加することが好ましい。しかし、0.01mass％を超えると耐食性が劣化するので、それぞれ0.01mass％以下に制限するのが好ましい。より好ましくはそれぞれ0.005mass％以下である。同様に、REMは、熱間加工性を向上させる成分として適宜添加することができ、その場合には、0.002mass％以上であることが好ましい。しかし、0.1mass％を超えると耐食性が劣化するので、0.1mass％以下に制限するのが好ましい。より好ましくは0.05mass％以下である。なお、上記REMは、La，Ce等の希土類元素のことを意味する。
B: 0.01 mass% or less, Ca: 0.01 mass% or less, Mg: 0.01 mass% or less, REM: Any one or more of 0.1 mass% or less B, Ca, Mg has hot workability It is a component to improve and can be added as appropriate. In order to obtain the effect, 0.0003 mass% or more is preferably added. However, since corrosion resistance will deteriorate if it exceeds 0.01 mass%, it is preferable to limit each to 0.01 mass% or less. More preferably, it is 0.005 mass% or less respectively. Similarly, REM can be appropriately added as a component for improving hot workability, and in that case, it is preferably 0.002 mass% or more. However, since corrosion resistance will deteriorate when it exceeds 0.1 mass%, it is preferable to limit to 0.1 mass% or less. More preferably, it is 0.05 mass% or less. The REM means a rare earth element such as La or Ce.
なお、その他に、Ti，Nbを添加してもよい。Tiは、熱間加工性を向上させる成分として適宜添加することができる。上記効果を得るためには、0.002mass％以上添加することが好ましい。しかし、0.1mass％を超えると耐食性が劣化するので、0.1mass％以下に制限するのが好ましい。Nbは、鋭敏化(粒界のクロム炭化物、クロム窒化物の生成による耐食性劣化)を抑える元素として添加することができる。上記効果を得るためには、0.002mass％以上添加することが好ましい。しかし、２mass％を超えると、Nbの炭窒化物が多量に生成し、鋼中の固溶Ｃ，Ｎが消費されるため好ましくない。
本発明のステンレス鋼においては、上記成分以外の残部は、Feおよび不可避的不純物である。なお、Ｏは、介在物による表面疵を防止する観点から、0.05mass％以下に制御するのが好ましい。
In addition, Ti and Nb may be added. Ti can be appropriately added as a component for improving hot workability. In order to acquire the said effect, adding 0.002 mass% or more is preferable. However, since corrosion resistance will deteriorate when it exceeds 0.1 mass%, it is preferable to limit to 0.1 mass% or less. Nb can be added as an element that suppresses sensitization (corrosion resistance deterioration due to the formation of chromium carbide and chromium nitride at grain boundaries). In order to acquire the said effect, adding 0.002 mass% or more is preferable. However, if it exceeds 2 mass%, a large amount of Nb carbonitride is generated and solute C and N in the steel are consumed, which is not preferable.
In the stainless steel of the present invention, the balance other than the above components is Fe and inevitable impurities. In addition, it is preferable to control O to 0.05 mass% or less from a viewpoint of preventing the surface flaw by an inclusion.
表１に示した成分組成を有する各種鋼を真空溶解あるいは窒素分圧を制御した雰囲気下で溶製し、鋼スラブとした後、常法に従って、熱間圧延、冷間圧延し、その後、窒素分圧を制御した雰囲気下で、表２に示したように950〜1300℃の温度範囲で30〜600秒の仕上焼鈍を行い、オーステナイト相の体積分率およびオーステナイト相中のＣとＮの合計量が異なる、板厚：1.25mmの各種冷延焼鈍板を作製し、これらの冷延焼鈍板について、下記の要領で、組織観察、オーステナイト相中のＣ，Ｎ分析および限界絞り比(ＬＤＲ)の測定を行った。
＜組織観察＞
冷延焼鈍板の圧延方向の断面組織を、光学顕微鏡を用いて500倍で全厚×0.1mm以上の範囲に亘って観察し、オーステナイト相の面積率を測定してオーステナイト相の体積分率とした。具体的には、試料の圧延方向断面を研磨した後、赤血塩溶液(フェリシアン化カリウム30ｇ＋水酸化カリウム30ｇ＋水60ｍｌ)あるいは王水でエッチング後、白黒写真撮影を行い、白色部(オーステナイト相とマルテンサイト相)と灰色部(フェライト相)の占める割合を画像解析により求め、白色部の分率をオーステナイト相の体積分率とした。なお、まれに、白色部と灰色部が反転することがあるが、この場合は、ＥＰＭＡ分析を併用することで確認することができる。
＜オーステナイト相中のＣ，Ｎ分析＞
上記断面を研摩した試料を用いて、ＥＰＭＡによるオーステナイト相中のＣ，Ｎの分析を行った。具体的には、Ｃ，Ｎは、オーステナイト相に濃化する特徴があるので、まず、断面全体について、ＣまたはＮの定性マッピングを行ってオーステナイト相を特定した後、フェライト相に電子ビームがかからないように、オーステナイト相のほぼ中心部についてＣ，Ｎを定量分析した。測定領域は約１μmφの範囲で、各試料について３点以上測定し、その平均値を代表値とした。
＜限界絞り比＞
上記冷延焼鈍板から、直径(ブランク径)を種々の大きさに変えた円形の試験片を打ち抜き、この試験片を、ポンチ径：35mm、板押え力：１tonの条件で円筒絞り成形し、破断することなく絞れる最大のブランク径をポンチ径で割って限界絞り比(ＬＤＲ)を求め、深絞り性を評価した。なお、円筒絞り成形に用いた試験片の打ち抜き径は、絞り比が0.1間隔となるよう変化させた。
Various steels having the composition shown in Table 1 were melted in an atmosphere with vacuum melting or controlled nitrogen partial pressure to form a steel slab, followed by hot rolling and cold rolling according to a conventional method, and then nitrogen. In a controlled partial pressure atmosphere, finish annealing is performed for 30 to 600 seconds in the temperature range of 950 to 1300 ° C as shown in Table 2, and the volume fraction of the austenite phase and the total of C and N in the austenite phase Various cold-rolled annealed sheets with different thicknesses and thicknesses of 1.25 mm were prepared, and these cold-rolled annealed sheets were subjected to structure observation, C and N analysis in the austenite phase, and limit drawing ratio (LDR) in the following manner. Was measured.
<Tissue observation>
The cross-sectional structure in the rolling direction of the cold-rolled annealed sheet was observed over a range of 500 mm or more in total thickness x 0.1 mm using an optical microscope, and the area ratio of the austenite phase was measured to determine the volume fraction of the austenite phase. did. Specifically, after polishing the cross section in the rolling direction of the sample, it was etched with a red blood salt solution (30 g of potassium ferricyanide + 30 g of potassium hydroxide + 60 ml of water) or aqua regia, and then a black and white photograph was taken to obtain a white portion (austenite phase and martensite). The proportion of the site portion) and the gray portion (ferrite phase) was determined by image analysis, and the white portion fraction was defined as the volume fraction of the austenite phase. In rare cases, the white part and the gray part may be reversed, but in this case, it can be confirmed by using EPMA analysis together.
<Analysis of C and N in austenite phase>
Analysis of C and N in the austenite phase by EPMA was performed using a sample whose surface was polished. Specifically, since C and N have a feature of being concentrated in the austenite phase, first, the qualitative mapping of C or N is performed on the entire cross section to identify the austenite phase, and then no electron beam is applied to the ferrite phase. As described above, C and N were quantitatively analyzed in the substantially central part of the austenite phase. The measurement area was about 1 μmφ, and three or more points were measured for each sample, and the average value was used as the representative value.
<Limit drawing ratio>
From the cold-rolled annealed plate, circular test pieces with different diameters (blank diameters) were punched out, and this test piece was subjected to cylindrical drawing under the conditions of punch diameter: 35 mm and plate pressing force: 1 ton. The maximum blank diameter that can be squeezed without breaking was divided by the punch diameter to determine the limit drawing ratio (LDR), and the deep drawability was evaluated. The punching diameter of the test piece used for the cylindrical drawing was changed so that the drawing ratio was 0.1 interval.
上記測定の結果を表２に併記して示した。また、図１に、限界絞り比に及ぼす鋼中のNi量、オーステナイト相の体積分率およびオーステナイト相中のＣとＮの合計量の影響を示した。これらの結果から、本発明の条件を満たす、すなわち、Niを１〜３mass％含有し、オーステナイト相の体積分率が10〜85％で、かつオーステナイト相中のＣとＮの合計量が0.16〜２％であるオーステナイト・フェライト系ステンレス鋼板は、いずれも限界絞り比が2.1以上の高い値を示しており、深絞り性に優れていることがわかる。これに対して、オーステナイト相の体積分率が10〜85％の範囲外および／またはオーステナイト中のＣとＮの合計量が0.16mass％未満のオーステナイト・フェライト系ステンレス鋼板は、いずれも限界絞り比が2.1未満と低く、深絞り性が劣ることがわかる。また、オーステナイト相の体積分率およびオーステナイト相中のＣとＮの合計量が本発明範囲内でも、鋼板中のNi量が３mass％を超えるオーステナイト・フェライト系ステンレス鋼板は、やはり限界絞り比が2.1未満と低く、深絞り性が劣ることがわかる。 The results of the above measurements are shown together in Table 2. FIG. 1 shows the effects of the amount of Ni in the steel, the volume fraction of the austenite phase, and the total amount of C and N in the austenite phase on the limit drawing ratio. From these results, the conditions of the present invention are satisfied, that is, containing 1 to 3 mass% of Ni, the volume fraction of the austenite phase is 10 to 85%, and the total amount of C and N in the austenite phase is 0.16 to All the 2% austenitic and ferritic stainless steel sheets have a high limit drawing ratio of 2.1 or higher, indicating that they are excellent in deep drawability. On the other hand, austenitic and ferritic stainless steel sheets whose volume fraction of austenite phase is outside the range of 10 to 85% and / or the total amount of C and N in the austenite is less than 0.16 mass% are all limited drawing ratios. Is as low as less than 2.1, indicating that the deep drawability is poor. In addition, even when the volume fraction of the austenite phase and the total amount of C and N in the austenite phase are within the range of the present invention, the austenite-ferritic stainless steel plate in which the Ni content in the steel plate exceeds 3 mass% still has a limit drawing ratio of 2.1. It can be seen that the deep drawability is poor.
表３に示した成分組成を有する各種鋼を真空溶解あるいは窒素分圧を０〜１気圧に制御した雰囲気下で溶製し、鋼スラブとした後、常法に従って、熱間圧延、熱延板焼鈍、冷間圧延し、表４に示した焼鈍温度で１分間の仕上焼鈍を行い、オーステナイト相の体積分率およびオーステナイト相中のＣとＮの合計量が異なる板厚0.8mmの各種冷延焼鈍板を作製した。上記のようにして得た冷延焼鈍板について、下記の要領で、組織観察、オーステナイト相中の成分分析、引張試験および限界絞り比(ＬＤＲ)の測定を行った。
＜組織観察＞
冷延焼鈍板の圧延方向の断面組織を、光学顕微鏡を用いて、500倍で全厚×0.1mm以上の範囲に亘って観察し、オーステナイト相の面積率を測定してオーステナイト相の体積分率とした。具体的には、試料の圧延方向断面を研磨した後、赤血塩溶液(フェリシアン化カリウム30ｇ＋水酸化カリウム30ｇ＋水60ｍｌ)または王水でエッチング後、白黒写真撮影を行い、白色部(オーステナイト相とマルテンサイト相)と灰色部(フェライト相)の占める割合を画像解析により求め、白色部の分率をオーステナイト相の体積分率とした。
＜オーステナイト相中の成分分析＞
上記断面を研摩した試料を用いて、ＥＰＭＡによるオーステナイト相中の成分分析を行った。具体的には、Ｃ，Ｎは、オーステナイト相に濃化する特徴があるので、まず、断面全体について、ＣまたはＮの定性マッピングを行ってオーステナイト相を特定した上で、フェライト相に電子ビームがかからないようにオーステナイト相のほぼ中心部について、Ｃ，Ｎ，Si，Mn，Cr，Ni，CuおよびMoを定量分析した。測定領域は約１μmφの範囲で、各試料について３点以上測定し、その平均値を代表値とした。その結果を、表４に示した。また、これらの測定値を元に、下記式；
Ｍd(γ)＝551−462(Ｃ(γ)＋Ｎ(γ))−9.2Si(γ)−8.1Mn(γ)−13.7Cr(γ)−29Ni(γ)−29Cu(γ)−18.5Mo(γ)
ただし、Ｃ(γ)、Ｎ(γ)、Si(γ)、Mn(γ)、Cr(γ)、Ni(γ)、Cu(γ)およびMo(γ)は、それぞれオーステナイト相中のＣ量(mass％)、Ｎ量(mass％)、Si量(mass％)、Mn量(mass％)、Cr量(mass％)、Ni量(mass％)、Cu量(mass％)、Mo量(mass％)
で定義される加工誘起マルテンサイト指数(Ｍd(γ))を求めた。
＜引張試験＞
冷延焼鈍板から、圧延方向に対して０°(平行)、45°および90°の各方向からＪＩＳ １３号Ｂ引張試験片を採取して、室温、大気中で、引張速度10mm／分の条件で引張試験を行った。引張試験では、各方向の破断までの全伸びを測定し、下記式；
Ｅｌ＝{Ｅｌ(０°)＋２Ｅｌ(45°)＋Ｅｌ(90°)}／４)
を用いて平均伸び(Ｅｌ)を計算し、これを全伸びとして評価した。
＜限界絞り比＞
上記冷延焼鈍板から、直径(ブランク径)を種々の大きさに変えた円形の試験片を打ち抜き、この試験片を、ポンチ径：35mm、板押え力：１tonの条件で円筒絞り成形し、破断することなく絞れる最大のブランク径をポンチ径で割って限界絞り比(ＬＤＲ)を求め、深絞り性を評価した。なお、円筒絞り成形に用いた試験片の打ち抜き径は、絞り比が0.1間隔となるよう変化させた。
Various steels having the composition shown in Table 3 were melted under vacuum or in an atmosphere in which the nitrogen partial pressure was controlled to 0 to 1 atm to form a steel slab, followed by hot rolling and hot rolling in accordance with conventional methods. Annealing and cold rolling, finish annealing for 1 minute at the annealing temperature shown in Table 4, various cold rolling with 0.8mm thickness with different volume fraction of austenite phase and total amount of C and N in austenite phase An annealed plate was produced. The cold-rolled annealed sheet obtained as described above was subjected to structure observation, component analysis in the austenite phase, tensile test, and measurement of limit drawing ratio (LDR) in the following manner.
<Tissue observation>
The cross-sectional structure in the rolling direction of the cold-rolled annealed sheet is observed over an area of 500 times the total thickness x 0.1 mm or more using an optical microscope, and the area ratio of the austenite phase is measured to determine the volume fraction of the austenite phase. It was. Specifically, after polishing the cross section in the rolling direction of the sample, after etching with a red blood salt solution (potassium ferricyanide 30 g + potassium hydroxide 30 g + 60 ml water) or aqua regia, a black and white photograph was taken, and the white part (austenite phase and martensite) The proportion of the site portion) and the gray portion (ferrite phase) was determined by image analysis, and the white portion fraction was defined as the volume fraction of the austenite phase.
<Analysis of components in austenite phase>
Component analysis in the austenite phase was performed by EPMA using a sample obtained by polishing the cross section. Specifically, since C and N have a feature of being concentrated in the austenite phase, first, the qualitative mapping of C or N is performed on the entire cross section to identify the austenite phase, and then an electron beam is generated in the ferrite phase. C, N, Si, Mn, Cr, Ni, Cu and Mo were quantitatively analyzed about the substantially central part of the austenite phase so as not to be applied. The measurement area was about 1 μmφ, and three or more points were measured for each sample, and the average value was used as the representative value. The results are shown in Table 4. In addition, based on these measured values, the following formula:
Md (γ) = 551−462 (C (γ) + N (γ)) − 9.2Si (γ) −8.1Mn (γ) −13.7Cr (γ) −29Ni (γ) −29Cu (γ) −18.5Mo ( γ)
However, C (γ), N (γ), Si (γ), Mn (γ), Cr (γ), Ni (γ), Cu (γ) and Mo (γ) are the amounts of C in the austenite phase, respectively. (mass%), N amount (mass%), Si amount (mass%), Mn amount (mass%), Cr amount (mass%), Ni amount (mass%), Cu amount (mass%), Mo amount ( mass%)
The processing-induced martensite index (Md (γ)) defined by
<Tensile test>
JIS No. 13 B tensile test specimens were taken from cold-rolled annealed plates from 0 ° (parallel), 45 ° and 90 ° directions with respect to the rolling direction. A tensile test was performed under the conditions. In the tensile test, the total elongation to break in each direction is measured and the following formula:
El = {El (0 °) + 2El (45 °) + El (90 °)} / 4)
Was used to calculate the average elongation (El), and this was evaluated as the total elongation.
<Limit drawing ratio>
From the cold-rolled annealed plate, circular test pieces having different diameters (blank diameters) were punched out, and this test piece was subjected to cylindrical drawing under the conditions of punch diameter: 35 mm and plate pressing force: 1 ton. The maximum blank diameter that could be squeezed without breaking was divided by the punch diameter to determine the limit drawing ratio (LDR), and the deep drawability was evaluated. The punching diameter of the test piece used for the cylindrical drawing was changed so that the drawing ratio was 0.1 interval.
上記試験の結果を、表４中に併記して示した。オーステナイト相中のＣとＮの合計量が0.16〜２mass％である本発明の鋼板でも、Ｍd(γ)を適正な範囲に制御することにより、更に大きく改善され、特に、Ｍd(γ)を−30〜90の範囲に制御した場合には、全伸びが48％以上(板厚0.8mm)と、非常に優れた延性特性が得られることがわかる。 The results of the above test are shown together in Table 4. Even in the steel sheet of the present invention in which the total amount of C and N in the austenite phase is 0.16 to 2 mass%, the Md (γ) is further improved by controlling the Md (γ) to an appropriate range. It can be seen that when the thickness is controlled in the range of 30 to 90, the total elongation is 48% or more (plate thickness 0.8 mm), and very excellent ductility characteristics can be obtained.
本発明鋼は、自動車部材や厨房機器等の素材として好適に用いることができる。 The steel of the present invention can be suitably used as a material for automobile members and kitchen equipment.
Claims (5)
In addition to the above component composition, B: 0.01 mass% or less, Ca: 0.01 mass% or less, Mg: 0.01 mass% or less, REM: 0.1 mass% or less, or one or more of them are contained. The austenitic ferritic stainless steel according to any one of claims 1 to 4, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005023492A JP4760032B2 (en) | 2004-01-29 | 2005-01-31 | Austenitic ferritic stainless steel with excellent formability |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004021283 | 2004-01-29 | ||
| JP2004021283 | 2004-01-29 | ||
| JP2004347306 | 2004-11-30 | ||
| JP2004347306 | 2004-11-30 | ||
| JP2005023492A JP4760032B2 (en) | 2004-01-29 | 2005-01-31 | Austenitic ferritic stainless steel with excellent formability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2006183129A true JP2006183129A (en) | 2006-07-13 |
| JP4760032B2 JP4760032B2 (en) | 2011-08-31 |
Family
ID=36736454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005023492A Active JP4760032B2 (en) | 2004-01-29 | 2005-01-31 | Austenitic ferritic stainless steel with excellent formability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4760032B2 (en) |
Cited By (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008163359A (en) * | 2006-12-27 | 2008-07-17 | Nippon Steel & Sumikin Stainless Steel Corp | Stainless steel sheet for structural member having excellent impact absorbing property |
| JP2008291282A (en) * | 2007-05-22 | 2008-12-04 | Nippon Steel & Sumikin Stainless Steel Corp | High strength dual-phase stainless steel sheet with excellent shape fixability, and its manufacturing method |
| WO2009017258A1 (en) | 2007-08-02 | 2009-02-05 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic-austenitic stainless steel excellent in corrosion resistance and workability and process for manufacturing the same |
| JP2009035782A (en) * | 2007-08-02 | 2009-02-19 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel with excellent corrosion resistance and workability, and its manufacturing method |
| WO2009093652A1 (en) | 2008-01-22 | 2009-07-30 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-austenite stainless steel sheet for structural members excellent in workability and impact absorption characteristics and process for the production of the sheet |
| WO2009099010A1 (en) | 2008-02-05 | 2009-08-13 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-austenite stainless steel sheet excellent in ridging resistance and workability and process for manufacturing the same |
| WO2009119895A1 (en) | 2008-03-26 | 2009-10-01 | 新日鐵住金ステンレス株式会社 | Low-alloy duplex stainless steel wherein weld heat-affected zones have good corrosion resistance and toughness |
| JP2010059541A (en) * | 2008-08-04 | 2010-03-18 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel having excellent ingot crack resistance and workability, and method for producing the same |
| JP2010084220A (en) * | 2008-10-02 | 2010-04-15 | Nippon Steel & Sumikin Stainless Steel Corp | Two phase stainless hot-rolled steel having excellent impact toughness and method for producing the same |
| WO2011102499A1 (en) * | 2010-02-18 | 2011-08-25 | 新日鐵住金ステンレス株式会社 | Duplex stainless steel material for vacuum vessels, and process for manufacturing same |
| JP2011184792A (en) * | 2010-02-12 | 2011-09-22 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel sheet having excellent press formability, and method for producing the same |
| JP2011208244A (en) * | 2010-03-30 | 2011-10-20 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel sheet to be press-formed causing small earring, and method for manufacturing the same |
| WO2011135170A1 (en) | 2010-04-29 | 2011-11-03 | Outokumpu Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| JP2012126992A (en) * | 2010-11-25 | 2012-07-05 | Jfe Steel Corp | Austenite-ferrite duplex stainless steel for fuel tank |
| WO2012121380A1 (en) | 2011-03-09 | 2012-09-13 | 新日鐵住金ステンレス株式会社 | Two-phase stainless steel exhibiting excellent corrosion resistance in weld |
| WO2013113718A1 (en) * | 2012-02-03 | 2013-08-08 | Klaus Kuhn Edelstahlgiesserei Gmbh | Duplex steel with improved notch-impact strength and machinability |
| CN103547695A (en) * | 2011-04-18 | 2014-01-29 | 奥托库姆普联合股份公司 | Method for manufacturing and utilizing ferritic-austenitic stainless steel |
| CN103890214A (en) * | 2011-09-07 | 2014-06-25 | 奥托库姆普联合股份公司 | Duplex stainless steel |
| EP2762597A4 (en) * | 2011-09-28 | 2015-08-19 | Posco | Low-alloy duplex stainless steel having outstanding corrosion resistance and hot working properties |
| JP2015221945A (en) * | 2007-11-29 | 2015-12-10 | エイティーアイ・プロパティーズ・インコーポレーテッド | Lean austenitic stainless steel |
| US20160115574A1 (en) * | 2013-06-13 | 2016-04-28 | Outokumpu Oyj | Duplex ferritic austenitic stainless steel |
| US9624564B2 (en) | 2007-12-20 | 2017-04-18 | Ati Properties Llc | Corrosion resistant lean austenitic stainless steel |
| JP6140856B1 (en) * | 2016-02-19 | 2017-05-31 | 新日鐵住金ステンレス株式会社 | Ferritic / austenitic stainless steel sheet with excellent formability and method for producing the same |
| JP2017145460A (en) * | 2016-02-17 | 2017-08-24 | 新日鐵住金ステンレス株式会社 | Ferrite-austenitic stainless steel sheet for structural member excellent in puncture resistance at low temperature and manufacturing method thereof |
| US9822435B2 (en) | 2007-12-20 | 2017-11-21 | Ati Properties Llc | Lean austenitic stainless steel |
| US9862168B2 (en) | 2011-01-27 | 2018-01-09 | Nippon Steel & Sumikin Stainless Steel Corporation | Alloying element-saving hot rolled duplex stainless steel material, clad steel plate having duplex stainless steel as cladding material therefor, and production method for same |
| US9873932B2 (en) | 2007-12-20 | 2018-01-23 | Ati Properties Llc | Lean austenitic stainless steel containing stabilizing elements |
| JP6315158B1 (en) * | 2017-09-19 | 2018-04-25 | 新日鐵住金株式会社 | Stainless steel sheet and method for producing the same, separator for polymer electrolyte fuel cell, polymer electrolyte fuel cell, and polymer electrolyte fuel cell |
| WO2018117477A1 (en) * | 2016-12-23 | 2018-06-28 | 주식회사 포스코 | Duplex stainless steel having excellent corrosion resistance and moldability, and manufacturing method therefor |
| JP2018197377A (en) * | 2017-05-24 | 2018-12-13 | Ｊｆｅスチール株式会社 | Two-phase stainless steel having excellent corrosion resistance and hydrogen brittleness resistance |
| JP2018197376A (en) * | 2017-05-24 | 2018-12-13 | Ｊｆｅスチール株式会社 | Two-phase stainless steel having excellent corrosion resistance and hydrogen brittleness resistance |
| CN111742075A (en) * | 2018-02-15 | 2020-10-02 | 山特维克知识产权股份有限公司 | Novel duplex stainless steel |
| WO2021241133A1 (en) * | 2020-05-28 | 2021-12-02 | 日鉄ステンレス株式会社 | Two-phase ferrite/austenite stainless steel material and corrosion resistant member |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3556879A4 (en) | 2017-01-23 | 2020-01-15 | JFE Steel Corporation | Ferritic/austenitic duplex stainless steel plate |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5651222B1 (en) * | 1970-12-23 | 1981-12-03 | ||
| JPH02305940A (en) * | 1989-05-22 | 1990-12-19 | Nippon Steel Corp | Two-phase stainless steel for building material |
| JPH05247594A (en) * | 1992-03-03 | 1993-09-24 | Sumitomo Metal Ind Ltd | Dual phase stainless steel excellent in weatherability |
| JPH10219407A (en) * | 1997-02-07 | 1998-08-18 | Kawasaki Steel Corp | Ferritic stainless steel excellent in ductility, and its production |
| WO2002027056A1 (en) * | 2000-09-27 | 2002-04-04 | Avestapolarit Aktiebolag (Publ) | Ferritic-austenitic stainless steel |
-
2005
- 2005-01-31 JP JP2005023492A patent/JP4760032B2/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5651222B1 (en) * | 1970-12-23 | 1981-12-03 | ||
| JPH02305940A (en) * | 1989-05-22 | 1990-12-19 | Nippon Steel Corp | Two-phase stainless steel for building material |
| JPH05247594A (en) * | 1992-03-03 | 1993-09-24 | Sumitomo Metal Ind Ltd | Dual phase stainless steel excellent in weatherability |
| JPH10219407A (en) * | 1997-02-07 | 1998-08-18 | Kawasaki Steel Corp | Ferritic stainless steel excellent in ductility, and its production |
| WO2002027056A1 (en) * | 2000-09-27 | 2002-04-04 | Avestapolarit Aktiebolag (Publ) | Ferritic-austenitic stainless steel |
Cited By (66)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008163359A (en) * | 2006-12-27 | 2008-07-17 | Nippon Steel & Sumikin Stainless Steel Corp | Stainless steel sheet for structural member having excellent impact absorbing property |
| JP2008291282A (en) * | 2007-05-22 | 2008-12-04 | Nippon Steel & Sumikin Stainless Steel Corp | High strength dual-phase stainless steel sheet with excellent shape fixability, and its manufacturing method |
| EP3434802A1 (en) | 2007-08-02 | 2019-01-30 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic-austenitic stainless steel excellent in corrosion resistance and workability and method of production of same |
| WO2009017258A1 (en) | 2007-08-02 | 2009-02-05 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic-austenitic stainless steel excellent in corrosion resistance and workability and process for manufacturing the same |
| JP2009035782A (en) * | 2007-08-02 | 2009-02-19 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel with excellent corrosion resistance and workability, and its manufacturing method |
| US9617628B2 (en) | 2007-11-29 | 2017-04-11 | Ati Properties Llc | Lean austenitic stainless steel |
| US10370748B2 (en) | 2007-11-29 | 2019-08-06 | Ati Properties Llc | Lean austenitic stainless steel |
| JP2015221945A (en) * | 2007-11-29 | 2015-12-10 | エイティーアイ・プロパティーズ・インコーポレーテッド | Lean austenitic stainless steel |
| US10323308B2 (en) | 2007-12-20 | 2019-06-18 | Ati Properties Llc | Corrosion resistant lean austenitic stainless steel |
| US9873932B2 (en) | 2007-12-20 | 2018-01-23 | Ati Properties Llc | Lean austenitic stainless steel containing stabilizing elements |
| US9822435B2 (en) | 2007-12-20 | 2017-11-21 | Ati Properties Llc | Lean austenitic stainless steel |
| US9624564B2 (en) | 2007-12-20 | 2017-04-18 | Ati Properties Llc | Corrosion resistant lean austenitic stainless steel |
| US8303733B2 (en) | 2008-01-22 | 2012-11-06 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-austenite stainless steel sheet for structural component excellent in workability and impact-absorbing property and method for producing the same |
| WO2009093652A1 (en) | 2008-01-22 | 2009-07-30 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-austenite stainless steel sheet for structural members excellent in workability and impact absorption characteristics and process for the production of the sheet |
| WO2009099010A1 (en) | 2008-02-05 | 2009-08-13 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-austenite stainless steel sheet excellent in ridging resistance and workability and process for manufacturing the same |
| US8226780B2 (en) | 2008-02-05 | 2012-07-24 | Nippon Steel | Ferrite-austenite stainless steel sheet excellent in ridging resistance and workability and process for manufacturing the same |
| KR20160010887A (en) | 2008-03-26 | 2016-01-28 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Low-alloy duplex stainless steel wherein weld heat-affected zones have good corrosion resistance and toughness |
| US9212412B2 (en) | 2008-03-26 | 2015-12-15 | Nippon Steel & Sumikin Stainless Steel Corporation | Lean duplex stainless steel excellent in corrosion resistance and toughness of weld heat affected zone |
| WO2009119895A1 (en) | 2008-03-26 | 2009-10-01 | 新日鐵住金ステンレス株式会社 | Low-alloy duplex stainless steel wherein weld heat-affected zones have good corrosion resistance and toughness |
| KR20160010886A (en) | 2008-03-26 | 2016-01-28 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Low-alloy duplex stainless steel wherein weld heat-affected zones have good corrosion resistance and toughness |
| JP2010059541A (en) * | 2008-08-04 | 2010-03-18 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel having excellent ingot crack resistance and workability, and method for producing the same |
| JP2010084220A (en) * | 2008-10-02 | 2010-04-15 | Nippon Steel & Sumikin Stainless Steel Corp | Two phase stainless hot-rolled steel having excellent impact toughness and method for producing the same |
| JP2011184792A (en) * | 2010-02-12 | 2011-09-22 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel sheet having excellent press formability, and method for producing the same |
| CN102770572A (en) * | 2010-02-18 | 2012-11-07 | 新日铁住金不锈钢株式会社 | Duplex stainless steel material for vacuum vessels, and process for manufacturing same |
| WO2011102499A1 (en) * | 2010-02-18 | 2011-08-25 | 新日鐵住金ステンレス株式会社 | Duplex stainless steel material for vacuum vessels, and process for manufacturing same |
| JP2011168838A (en) * | 2010-02-18 | 2011-09-01 | Nippon Steel & Sumikin Stainless Steel Corp | Duplex stainless steel material for vacuum vessel and method for manufacturing the same |
| JP2011208244A (en) * | 2010-03-30 | 2011-10-20 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic-austenitic stainless steel sheet to be press-formed causing small earring, and method for manufacturing the same |
| JP2013530305A (en) * | 2010-04-29 | 2013-07-25 | オウトクンプ オサケイティオ ユルキネン | Production and utilization of ferritic / austenitic stainless steel with high formability |
| EP2563945A1 (en) | 2010-04-29 | 2013-03-06 | Outokumpu, Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| TWI512111B (en) * | 2010-04-29 | 2015-12-11 | Outokumpu Oy | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| WO2011135170A1 (en) | 2010-04-29 | 2011-11-03 | Outokumpu Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| US10407746B2 (en) | 2010-04-29 | 2019-09-10 | Outokumpu Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel |
| AU2011247272B2 (en) * | 2010-04-29 | 2016-04-28 | Outokumpu Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| EP2563945A4 (en) * | 2010-04-29 | 2016-12-07 | Outokumpu Oy | Method for manufacturing and utilizing ferritic-austenitic stainless steel with high formability |
| JP2012126992A (en) * | 2010-11-25 | 2012-07-05 | Jfe Steel Corp | Austenite-ferrite duplex stainless steel for fuel tank |
| US9862168B2 (en) | 2011-01-27 | 2018-01-09 | Nippon Steel & Sumikin Stainless Steel Corporation | Alloying element-saving hot rolled duplex stainless steel material, clad steel plate having duplex stainless steel as cladding material therefor, and production method for same |
| WO2012121380A1 (en) | 2011-03-09 | 2012-09-13 | 新日鐵住金ステンレス株式会社 | Two-phase stainless steel exhibiting excellent corrosion resistance in weld |
| US9365914B2 (en) | 2011-03-09 | 2016-06-14 | Nippon Steel & Sumikin Stainless Steel Corporation | Duplex stainless steel superior in corrosion resistance of weld |
| JP2014511944A (en) * | 2011-04-18 | 2014-05-19 | オウトクンプ オサケイティオ ユルキネン | Production and utilization of ferritic and austenitic stainless steels |
| EP2699704A1 (en) | 2011-04-18 | 2014-02-26 | Outokumpu, Oyj | Method for manufacturing and utilizing ferritic-austenitic stainless steel |
| CN103547695A (en) * | 2011-04-18 | 2014-01-29 | 奥托库姆普联合股份公司 | Method for manufacturing and utilizing ferritic-austenitic stainless steel |
| US11555231B2 (en) | 2011-09-07 | 2023-01-17 | Outokumpu Oyj | Duplex stainless steel |
| EP2753724A1 (en) | 2011-09-07 | 2014-07-16 | Outokumpu Oyj | Duplex stainless steel |
| CN103890214A (en) * | 2011-09-07 | 2014-06-25 | 奥托库姆普联合股份公司 | Duplex stainless steel |
| US10280491B2 (en) | 2011-09-28 | 2019-05-07 | Posco | Low-alloy duplex stainless steel having outstanding corrosion resistance and hot working properties |
| EP2762597A4 (en) * | 2011-09-28 | 2015-08-19 | Posco | Low-alloy duplex stainless steel having outstanding corrosion resistance and hot working properties |
| WO2013113718A1 (en) * | 2012-02-03 | 2013-08-08 | Klaus Kuhn Edelstahlgiesserei Gmbh | Duplex steel with improved notch-impact strength and machinability |
| CN104254627A (en) * | 2012-02-03 | 2014-12-31 | 克劳斯·库恩不锈钢铸造有限公司 | Duplex steel with improved notch-impact strength and machinability |
| JP2015511272A (en) * | 2012-02-03 | 2015-04-16 | クラウス クーン エーデルシュタールギーセライ ゲーエムベーハー | Duplex steel with improved notched impact strength and machinability |
| AU2014279972B2 (en) * | 2013-06-13 | 2018-01-04 | Outokumpu Oyj | Duplex ferritic austenitic stainless steel |
| US11566309B2 (en) * | 2013-06-13 | 2023-01-31 | Outokumpu Oyj | Duplex ferritic austenitic stainless steel |
| JP2016526601A (en) * | 2013-06-13 | 2016-09-05 | オウトクンプ オサケイティオ ユルキネンＯｕｔｏｋｕｍｐｕ Ｏｙｊ | Duplex ferrite and austenitic stainless steel |
| US20160115574A1 (en) * | 2013-06-13 | 2016-04-28 | Outokumpu Oyj | Duplex ferritic austenitic stainless steel |
| JP2017145460A (en) * | 2016-02-17 | 2017-08-24 | 新日鐵住金ステンレス株式会社 | Ferrite-austenitic stainless steel sheet for structural member excellent in puncture resistance at low temperature and manufacturing method thereof |
| JP6140856B1 (en) * | 2016-02-19 | 2017-05-31 | 新日鐵住金ステンレス株式会社 | Ferritic / austenitic stainless steel sheet with excellent formability and method for producing the same |
| JP2017145487A (en) * | 2016-02-19 | 2017-08-24 | 新日鐵住金ステンレス株式会社 | Ferrite austenite stainless steel sheet excellent in moldability and manufacturing method therefor |
| WO2018117477A1 (en) * | 2016-12-23 | 2018-06-28 | 주식회사 포스코 | Duplex stainless steel having excellent corrosion resistance and moldability, and manufacturing method therefor |
| JP2018197377A (en) * | 2017-05-24 | 2018-12-13 | Ｊｆｅスチール株式会社 | Two-phase stainless steel having excellent corrosion resistance and hydrogen brittleness resistance |
| JP2018197376A (en) * | 2017-05-24 | 2018-12-13 | Ｊｆｅスチール株式会社 | Two-phase stainless steel having excellent corrosion resistance and hydrogen brittleness resistance |
| WO2019058409A1 (en) * | 2017-09-19 | 2019-03-28 | 新日鐵住金株式会社 | Stainless steel sheet and production method therefor, separator for solid polymer fuel battery, solid polymer fuel battery cell and solid polymer fuel battery |
| JP6315158B1 (en) * | 2017-09-19 | 2018-04-25 | 新日鐵住金株式会社 | Stainless steel sheet and method for producing the same, separator for polymer electrolyte fuel cell, polymer electrolyte fuel cell, and polymer electrolyte fuel cell |
| CN111742075A (en) * | 2018-02-15 | 2020-10-02 | 山特维克知识产权股份有限公司 | Novel duplex stainless steel |
| US11306378B2 (en) | 2018-02-15 | 2022-04-19 | Sandvik Intellectual Property Ab | Duplex stainless steel |
| CN114901870A (en) * | 2020-05-28 | 2022-08-12 | 日铁不锈钢株式会社 | Ferritic-austenitic duplex stainless steel material and corrosion resistant member |
| WO2021241133A1 (en) * | 2020-05-28 | 2021-12-02 | 日鉄ステンレス株式会社 | Two-phase ferrite/austenite stainless steel material and corrosion resistant member |
| CN114901870B (en) * | 2020-05-28 | 2024-02-06 | 日铁不锈钢株式会社 | Ferrite-austenite duplex stainless steel material and corrosion resistant member |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4760032B2 (en) | 2011-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4760032B2 (en) | Austenitic ferritic stainless steel with excellent formability | |
| JP4760031B2 (en) | Austenitic ferritic stainless steel with excellent formability | |
| KR100957664B1 (en) | Austenitic-ferritic stainless steel sheet | |
| JP5021901B2 (en) | Austenitic and ferritic stainless steel with excellent intergranular corrosion resistance | |
| JP4852857B2 (en) | Ferritic / austenitic stainless steel sheet with excellent stretch formability and crevice corrosion resistance | |
| JP3504560B2 (en) | High-strength hot-rolled steel sheet with good shape-freezing properties and excellent formability | |
| JP5337473B2 (en) | Ferritic / austenitic stainless steel sheet with excellent ridging resistance and workability and method for producing the same | |
| JP5109233B2 (en) | Ferritic / austenitic stainless steel with excellent corrosion resistance at welds | |
| WO2009017258A1 (en) | Ferritic-austenitic stainless steel excellent in corrosion resistance and workability and process for manufacturing the same | |
| WO2013058274A1 (en) | Duplex stainless steel, duplex stainless steel slab, and duplex stainless steel material | |
| JP2009035782A (en) | Ferritic-austenitic stainless steel with excellent corrosion resistance and workability, and its manufacturing method | |
| JP2005089828A (en) | Ferritic stainless steel sheet improved in crevice corrosion resistance | |
| JP4867638B2 (en) | High-strength bolts with excellent delayed fracture resistance and corrosion resistance | |
| JP5404280B2 (en) | High-strength, alloy-saving duplex stainless steel with excellent corrosion resistance in the heat affected zone | |
| EP0735154A1 (en) | Austenitic stainless steels for press forming | |
| JP6279118B1 (en) | High-strength duplex stainless steel with excellent corrosion resistance and bending workability | |
| JP2007314837A (en) | Age hardening type ferritic stainless steel sheet and age-treated steel material using the same | |
| JP2017145487A (en) | Ferrite austenite stainless steel sheet excellent in moldability and manufacturing method therefor | |
| US11142814B2 (en) | Ferritic-austenitic duplex stainless steel sheet | |
| JP5653269B2 (en) | Stainless steel wire and steel wire excellent in corrosion resistance, strength, and ductility, and methods for producing them. | |
| JP2953303B2 (en) | Martensite stainless steel | |
| JP2022101237A (en) | Ferrite-martensite double-phase stainless steel having excellent bendability, and method for producing the same | |
| JP2023113375A (en) | Duplex stainless steel shapes and method for producing the same | |
| JPH1180911A (en) | High purity chromium steel sheet for pump impeller | |
| JP2021123751A (en) | Ferritic stainless steel material for roll molding |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20071108 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100201 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100406 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100607 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110215 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110411 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110510 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110523 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140617 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4760032 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |