JP2022041426A - Austenitic stainless steel sheet, and method for producing the same - Google Patents
Austenitic stainless steel sheet, and method for producing the same Download PDFInfo
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本発明は、自動車部品、電子機器類、バネ、その他工業部品用として好適なオーステナイト系ステンレス鋼板およびその製造方法に係り、耐食性、とくに耐孔食性の向上に関する。 The present invention relates to an austenitic stainless steel sheet suitable for automobile parts, electronic devices, springs, and other industrial parts, and a method for manufacturing the same, and relates to improvement of corrosion resistance, particularly pitting corrosion resistance.
フェライト系ステンレス鋼板の耐食性向上方法として、例えば、特許文献１に、「延性、耐摩耗性および耐銹性に優れた電気材料用フェライト系ステンレス鋼の製造方法」が記載されている。特許文献１に記載された技術では、仕上げ焼鈍後、10％以上の冷間圧延（ハード圧延）を施し、再加熱処理を行ったのち、例えば10％硝酸（20℃）中での硝酸電解を施して表面のスケールを除去することにより、耐食性を劣化させることなく、延性、耐摩耗性、および耐銹性に優れたフェライト系ステンレス鋼を製造できるとしている。 As a method for improving the corrosion resistance of a ferritic stainless steel sheet, for example, Patent Document 1 describes "a method for producing a ferritic stainless steel for electric materials having excellent ductility, wear resistance and rust resistance". In the technique described in Patent Document 1, after finish annealing, cold rolling (hard rolling) of 10% or more is performed, reheat treatment is performed, and then nitrate electrolysis in, for example, 10% nitric acid (20 ° C.) is performed. By removing the scale on the surface, it is possible to produce ferritic stainless steel with excellent ductility, wear resistance, and rust resistance without deteriorating corrosion resistance.
また、特許文献２には、「耐銹性に優れたフェライト系ステンレス鋼光輝焼鈍材の製造方法」が記載されている。特許文献２に記載された技術では、フェライト系ステンレス鋼板を焼鈍後、中性塩電解法および硝酸電解法を用いて脱スケールした後、冷間圧延を行い、さらに光輝焼鈍することにより、従来よりも、耐銹性に優れたフェライト系ステンレス鋼光輝焼鈍材が製造できるとしている。なお、硝酸電解法は、15％硝酸（50℃）中で交番電解した旨の記載がある。 Further, Patent Document 2 describes "a method for producing a ferritic stainless steel brightly annealed material having excellent rust resistance". In the technique described in Patent Document 2, a ferritic stainless steel sheet is annealed, descaled using a neutral salt electrolysis method and a nitrate electrolysis method, then cold-rolled, and further annealed by brilliance. Also, it is possible to manufacture ferritic stainless steel brightly annealed material with excellent corrosion resistance. In addition, there is a description that the nitric acid electrolysis method was alternately electrolyzed in 15% nitric acid (50 ° C).
また、特許文献３には、「耐食性の良好なステンレス鋼の製造方法」が記載されている。特許文献３に記載された技術では、Cr：11wt％以上35wt％以下を含有し、O：0.01wt％以下、S：0.01wt％以下に低減したステンレス鋼に対して、酸化剤を含む酸性水溶液を研磨液に用いて、機械研摩を行うことにより、耐食性が向上したステンレス鋼となるとしている。特許文献３に記載された技術では、機械研磨としてラッピング研磨、ベルト研磨を用いている。 Further, Patent Document 3 describes "a method for producing stainless steel having good corrosion resistance". In the technique described in Patent Document 3, an acidic aqueous solution containing an oxidizing agent is used for stainless steel containing Cr: 11 wt% or more and 35 wt% or less, O: 0.01 wt% or less, and S: 0.01 wt% or less. It is said that stainless steel with improved corrosion resistance can be obtained by mechanically polishing using the above as a polishing liquid. In the technique described in Patent Document 3, lapping polishing and belt polishing are used as mechanical polishing.
一方、オーステナイト系ステンレス鋼板は通常、熱処理後に冷間圧延することで機械的性質を向上させており、ある程度の耐孔食性は有している。しかし、塩素イオンを含む環境下や隙間構造、高温高湿といった環境下では、孔食が発生しやすい。そのため、このような環境下では、CrやMoを増加した鋼種(SUS316L等)が使用されることが多い。しかし、このような鋼種は高価であり、コスト面から、全ての環境下で使用できるものではない。 On the other hand, austenitic stainless steel sheets usually have improved mechanical properties by cold rolling after heat treatment, and have some degree of pitting corrosion resistance. However, pitting corrosion is likely to occur in an environment containing chloride ions, a gap structure, and an environment such as high temperature and high humidity. Therefore, in such an environment, steel grades with increased Cr and Mo (SUS316L, etc.) are often used. However, such steel grades are expensive and cannot be used in all environments in terms of cost.
一般的に、オーステナイト系ステンレス鋼板の製造時には、内部応力除去、固溶化、その他機械的特性改善のために、熱処理が行われる。しかし、燃料と酸素を含むガスとの燃焼ガス雰囲気はもちろん、窒素と水素の混合ガス中又は水素ガス雰囲気中などの還元雰囲中で熱処理を行っても、完全には酸化を防ぐことができず、表層に酸化被膜ができ、条件によっては表層直下にCr欠乏層ができて、耐食性が劣化することがある。そのため、耐食性を回復するために、従来から、燃料と酸素を含むガスとの燃焼ガス雰囲気及び還元性雰囲気中での熱処理後に、酸性液中に浸漬する処理を行ったり、様々な電解研磨等により耐食性を回復させることが行われている。 Generally, during the production of austenitic stainless steel sheets, heat treatment is performed to relieve internal stress, solidify, and improve other mechanical properties. However, oxidation can be completely prevented even if heat treatment is performed in a reducing atmosphere such as in a mixed gas of nitrogen and hydrogen or in a hydrogen gas atmosphere as well as in a combustion gas atmosphere of fuel and a gas containing oxygen. However, an oxide film is formed on the surface layer, and depending on the conditions, a Cr-deficient layer is formed immediately under the surface layer, which may deteriorate the corrosion resistance. Therefore, in order to restore the corrosion resistance, conventionally, after heat treatment in a combustion gas atmosphere and a reducing atmosphere of a gas containing fuel and oxygen, a treatment of immersing in an acidic liquid or various electrolytic polishing is performed. Restoration of corrosion resistance is being carried out.
特許文献１及び特許文献２に記載された技術は、いずれもフェライト系ステンレス鋼板の耐食性向上に関するものであり、特許文献１及び特許文献２には、オーステナイト系ステンレス鋼板についての記載はない。 Both the techniques described in Patent Document 1 and Patent Document 2 relate to improving the corrosion resistance of ferritic stainless steel sheets, and Patent Documents 1 and 2 do not describe austenitic stainless steel sheets.
また、特許文献３に記載された技術は、オーステナイト系ステンレス鋼板へも適用するとしているが、耐食性向上のために、酸性水溶液を用いてラッピング研摩等の機械研摩を行うことをその要件としている。オーステナイト系ステンレス鋼板では、表層の研摩時に機械的性質が変わる可能性があり、また表層の研摩により耐食性が劣化する懸念もある。さらに、表層の粗さを規定する製品に対しては、ラッピング研摩では対応できないという問題もある。 The technique described in Patent Document 3 is also applied to austenitic stainless steel plates, but it is a requirement that mechanical polishing such as wrapping polishing is performed using an acidic aqueous solution in order to improve corrosion resistance. In austenitic stainless steel sheets, the mechanical properties may change when the surface layer is polished, and there is a concern that the corrosion resistance may deteriorate due to the polishing of the surface layer. Further, there is a problem that wrapping polishing cannot deal with products that regulate the roughness of the surface layer.
本発明は、かかる従来技術の問題に鑑みてなされたものであり、耐食性、とくに耐孔食性に優れたオーステナイト系ステンレス鋼板およびその製造方法を提供することを目的とする。 The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide an austenitic stainless steel sheet having excellent corrosion resistance, particularly pitting corrosion resistance, and a method for producing the same.
本発明者らは、上記した目的を達成するために、オーステナイト系ステンレス鋼板の耐孔食性に及ぼす各種要因について鋭意検討した。 In order to achieve the above-mentioned object, the present inventors have diligently studied various factors affecting the pitting corrosion resistance of the austenitic stainless steel sheet.
その結果、熱延鋼板に、１回又は複数回の冷間圧延を施して冷延鋼板を製造するに当たり、前記冷間圧延のうちの最終の冷間圧延の後に、あるいは前記冷間圧延のうちの最終以外の冷間圧延の後に特定条件の熱処理を施した後に、適正条件の希硝酸電解処理を施すことにより、鋼板表面の孔食発生電位が高くなり、従来対応できなかった環境下においても、耐孔食性が向上することを知見した。 As a result, in producing a cold-rolled steel sheet by subjecting the hot-rolled steel sheet to cold-rolling once or a plurality of times, after the final cold-rolling of the cold-rolling, or after the cold-rolling of the cold-rolling. After cold rolling other than the final cold rolling, heat treatment under specific conditions is performed, and then dilute nitric acid electrolytic treatment under appropriate conditions is applied to increase the potential for pitting on the surface of the steel sheet, even in an environment that could not be dealt with in the past. , It was found that the corrosion resistance is improved.
まず、本発明の基礎となった実験結果について説明する。 First, the experimental results that form the basis of the present invention will be described.
質量％で、Cr：10.5～19.00％、Ni：0～13.50％、Mo：0～3.10％、N：0.02～0.06％、C:0.01～0.06％、Si：0.35～0.49％、Mn：0.65～1.10％を含む組成の焼鈍・酸洗済みの熱延鋼板（板厚：2.0mm）に、３回の冷間圧延を施して冷延鋼板を製造するに当たり、前記冷間圧延のうちの最終の冷間圧延の後に、あるいは前記冷間圧延のうちの最終以外の冷間圧延の後に、特殊な熱処理を施し、冷延鋼板（板厚：0.1mm）とした。なお、最終の冷間圧延後に施した熱処理は、加熱温度：690～980℃で、19ｓ～11min保持する処理とし、最終焼鈍前の中間焼鈍時は、690～1050℃、19ｓ～11min保持する熱処理とした。そして、得られた冷延鋼板にさらに、希硝酸電解処理を施したのち、表層を研磨せずに、JIS G 0577の規定に準拠して、各鋼板表面の孔食発生電位Ｖｃを測定した。また、測定に際しては、試験溶液（塩化ナトリウム水溶液）の脱気は行わなかった。なお、孔食発生電位の測定では、照合電極はAg/AgCl（塩化銀）電極とした。また、一部の鋼板については希硝酸電解処理は実施しなかった。 By mass%, Cr: 10.5 to 19.00%, Ni: 0 to 13.50%, Mo: 0 to 3.10%, N: 0.02 to 0.06%, C: 0.01 to 0.06%, Si: 0.35 to 0.49%, Mn: 0.65 to The final cold-rolled steel sheet (plate thickness: 2.0 mm) that has been annealed and pickled with a composition containing 1.10% is subjected to cold rolling three times to produce a cold-rolled steel sheet. After cold rolling, or after cold rolling other than the final of the cold rolling, a special heat treatment was applied to obtain a cold-rolled steel plate (plate thickness: 0.1 mm). The heat treatment performed after the final cold rolling is a heat treatment that holds the heating temperature at 690 to 980 ° C for 19s to 11min, and during the intermediate annealing before the final annealing, the heat treatment is held at 690 to 1050 ° C for 19s to 11min. And said. Then, the obtained cold-rolled steel sheet was further subjected to dilute nitric acid electrolysis treatment, and then the pitting corrosion potential Vc on the surface of each steel sheet was measured in accordance with the provisions of JIS G 0577 without polishing the surface layer. In addition, the test solution (sodium chloride aqueous solution) was not degassed during the measurement. In the measurement of the pitting corrosion potential, the reference electrode was an Ag / AgCl (silver chloride) electrode. In addition, dilute nitric acid electrolysis treatment was not performed on some steel sheets.
希硝酸電解処理の条件は、硝酸濃度：3％の希硝酸水溶液（液温：60℃）中で、電流密度：±30mA/cm2で、陽極・陰極電解を合計で20ｓ間、とした。電解方法としては、直接電解、間接電解、貫通電解、交番電解が考えられるが、今回は、間接電解で行った。得られた孔食発生電位Ｖｃと、孔食指数Ｘ（＝Cr＋3.3Mo）との関係を図１に示す。 The conditions for the dilute nitric acid electrolysis treatment were a dilute nitric acid aqueous solution (liquid temperature: 60 ° C.) with a nitric acid concentration of 3%, a current density of ± 30 mA / cm 2 , and an anode / cathode electrolysis for a total of 20 seconds. As the electrolysis method, direct electrolysis, indirect electrolysis, through electrolysis, and alternating electrolysis can be considered, but this time, indirect electrolysis was used. FIG. 1 shows the relationship between the obtained pitting corrosion potential Vc and the pitting corrosion index X (= Cr + 3.3Mo).
図１から、希硝酸電解処理を、冷間圧延後の熱処理と組み合わせて施した場合（●印）は、冷間圧延後の熱処理を施し、希硝酸電解処理を施さなかった場合（〇印）に比べて、孔食発生電位が高くなることがわかる。すなわち、希硝酸電解処理と熱処理とを組み合わせることが、耐孔食性の向上に有効であることになる。なお、孔食指数Ｘ（＝Cr＋3.3Mo）は、ステンレス鋼の孔食発生の難易度を表す指数である。孔食指数が高いほど耐孔食性が高くなる傾向を示す。なお、従来では孔食指数だけで孔食発生電位を予測していたが、高Cr側になると孔食指数の係数が違ってくることを知見し、孔食指数Ｘ（＝Cr＋3.3Mo）だけでは孔食発生電位を表現できないことを知見し、（１）式を見い出した。 From FIG. 1, when the dilute nitric acid electrolysis treatment was performed in combination with the heat treatment after cold rolling (● mark), the heat treatment after cold rolling was performed and the dilute nitric acid electrolysis treatment was not performed (○ mark). It can be seen that the potential for pitting corrosion is higher than that of the above. That is, the combination of the dilute nitric acid electrolysis treatment and the heat treatment is effective in improving the pitting corrosion resistance. The pitting corrosion index X (= Cr + 3.3Mo) is an index indicating the difficulty of pitting corrosion of stainless steel. The higher the pitting corrosion index, the higher the pitting corrosion resistance tends to be. In the past, the pitting corrosion potential was predicted only by the pitting corrosion index, but it was found that the coefficient of the pitting corrosion index differs on the high Cr side, and only the pitting corrosion index X (= Cr + 3.3Mo) is used. Then, it was found that the potential for pitting corrosion could not be expressed, and the equation (1) was found.
この実験結果から、希硝酸電解処理による孔食発生電位増加の閾値として、孔食指数Ｘ（＝Cr＋3.3Mo）との関係で、次式
Ａ ＝－0.006Ｘ3－0.35Ｘ2＋63Ｘ－646
（ここで、Ｘ＝Cr＋3.3Mo）
を定義した。この式は、希硝酸電解後の孔食発生電位の数値をプロットした際、それらの点の下限より小さく、なおかつ希硝酸電解前の孔食発生電位を上回る境界近辺の値で作成された近似曲線である。ステンレス鋼板表面の孔食発生電位Ｖｃが、上記したＡ値を超えて高くなる場合を、耐孔食性が向上しているとした。なお、孔食指数が15.0未満である鋼板では、希硝酸電解処理と熱処理とを組み合わせても、上記したＡ値を超えて、孔食発生電位の増加は認められなかった。このため、Ｘの範囲を15.0～40.0に限定した。
From this experimental result, the following equation A = -0.006X 3 -0.35X 2 + 63X-646 is used as the threshold value for the increase in pitting corrosion potential due to dilute nitric acid electrolysis treatment in relation to the pitting corrosion index X (= Cr + 3.3Mo).
(Here, X = Cr + 3.3Mo)
Was defined. This equation is an approximate curve created with values near the boundary that are smaller than the lower limit of these points and higher than the pitting corrosion potential before dilute nitric acid electrolysis when plotting the numerical values of the pitting corrosion potential after dilute nitric acid electrolysis. Is. When the pitting corrosion potential Vc on the surface of the stainless steel sheet exceeds the above A value, it is considered that the pitting corrosion resistance is improved. In the steel sheet having a pitting corrosion index of less than 15.0, no increase in the pitting corrosion potential was observed beyond the above A value even when the dilute nitric acid electrolysis treatment and the heat treatment were combined. Therefore, the range of X is limited to 15.0 to 40.0.
このようなことから、熱延鋼板に、１回又は複数回の冷間圧延を施して冷延鋼板を製造するに当たり、前記冷間圧延のうちの最終の冷間圧延の後に、あるいは前記冷間圧延のうちの最終以外の冷間圧延の後に、特定条件の熱処理を施し、その後に、適正条件の希硝酸電解処理を施すことにより、鋼板表面の孔食発生電位が高くなり、従来対応できなかった環境下においても適用可能な、優れた耐孔食性を有するステンレス鋼板（ステンレス冷延鋼板）とすることができることを知見した。なお、希硝酸電解処理の前又は後に、表面光沢を出すために極軽圧下の調質圧延を施しても問題はないことを知見している。 For this reason, when a hot-rolled steel sheet is cold-rolled once or a plurality of times to produce a cold-rolled steel sheet, after the final cold rolling of the cold rolling or the cold rolling. After cold rolling other than the final of rolling, heat treatment under specific conditions is performed, and then dilute nitrate electrolytic treatment under appropriate conditions is performed, so that the potential for pitting on the surface of the steel sheet becomes high, which cannot be dealt with in the past. It has been found that a stainless steel sheet (stainless cold-rolled steel sheet) having excellent pore corrosion resistance can be used even in an environment. It has been found that there is no problem even if temper rolling under extremely light pressure is performed before or after the dilute nitric acid electrolysis treatment in order to obtain surface gloss.
本発明は、かかる知見に基づき、さらに検討を加えて完成したものである。すなわち、本発明の要旨はつぎのとおりである。
［１］質量％で、
C：0.40％以下、 Si：1.00％以下、
Mn：2.00％以下、 P：0.045％以下、
S：0.030％以下、 Ni：3.5～20.0％、
Cr：15.00～30.00％、 Mo：0～3.5％、
N：0.30％以下
を含有し、かつCr、Moを次（２）式
Ｘ＝Cr＋3.3Mo……（２）
ここで、Cr、Mo：各元素の含有量（質量％）
で定義されるＸが15.0～40.0を満足するように含み、残部Feおよび不可避的不純物からなる組成を有し、かつ表面の孔食発生電位Ｖｃが、次（１）式
Ｖｃ ＞ －0.006Ｘ3－0.35Ｘ2＋63Ｘ－646 ……（１）
を満足することを特徴とするオーステナイト系ステンレス鋼板。
［２］前記組成に加えてさらに、質量％で、Ti：0.01～1.00％、Nb：0.01～1.00％、Cu：0.01～3.00％、Al：0.0001～1.50％、Ca：0.001～0.01％、Mg：0.001～0.01％、V：0.01～1.00％、Co：0.01～0.5％、W：0.01～1.0％、B:0.001～0.01％のうちから選ばれた１種または２種以上を含有する組成とすることを特徴とする［１］に記載のオーステナイト系ステンレス鋼板。
［３］鋼板の表面粗さがISO 25178の規定に準拠したSaで0.80μm以下であることを特徴とする［１］または［２］に記載のオーステナイト系ステンレス鋼板。
［４］［１］または［２］に記載の組成を有する熱延鋼板に、１回又は複数回の冷間圧延を施して冷延鋼板を製造するに当たり、
前記冷間圧延のうちの最終の冷間圧延の後に、あるいは前記冷間圧延のうちの最終以外の冷間圧延の後に、700℃超え950℃以下の範囲の温度で20ｓ～10min保持する熱処理を施し、最終に、希硝酸電解処理を施すことを特徴とするオーステナイト系ステンレス鋼板の製造方法。
［５］前記希硝酸電解処理が、硝酸濃度：3～10％、温度：30～65℃の希硝酸水溶液中で、電流密度：±10～80mA/cm2で、陰極および陽極電解を合計で10～60ｓ行う処理であることを特徴とする［４］に記載のオーステナイト系ステンレス鋼板の製造方法。
The present invention has been completed with further studies based on such findings. That is, the gist of the present invention is as follows.
[1] By mass%,
C: 0.40% or less, Si: 1.00% or less,
Mn: 2.00% or less, P: 0.045% or less,
S: 0.030% or less, Ni: 3.5-20.0%,
Cr: 15.00 to 30.00%, Mo: 0 to 3.5%,
N: Contains 0.30% or less, and Cr and Mo are contained in the following equation (2).
X = Cr + 3.3Mo …… (2)
Here, Cr, Mo: content of each element (mass%)
X defined in the above is contained so as to satisfy 15.0 to 40.0, has a composition consisting of the balance Fe and unavoidable impurities, and the pitting corrosion potential Vc on the surface is the following equation (1).
Vc> -0.006X 3 -0.35X 2 + 63X-646 …… (1)
Austenitic stainless steel sheet characterized by satisfying.
[2] In addition to the above composition, in mass%, Ti: 0.01 to 1.00%, Nb: 0.01 to 1.00%, Cu: 0.01 to 3.00%, Al: 0.0001 to 1.50%, Ca: 0.001 to 0.01%, Mg. : 0.001 to 0.01%, V: 0.01 to 1.00%, Co: 0.01 to 0.5%, W: 0.01 to 1.0%, B: 0.001 to 0.01% The austenitic stainless steel sheet according to [1].
[3] The austenitic stainless steel sheet according to [1] or [2], wherein the surface roughness of the steel sheet is 0.80 μm or less in Sa conforming to the regulation of ISO 25178.
[4] In manufacturing a cold-rolled steel sheet by subjecting a hot-rolled steel sheet having the composition according to [1] or [2] to cold rolling once or a plurality of times.
After the final cold rolling of the cold rolling, or after the non-final cold rolling of the cold rolling, heat treatment is performed to maintain the temperature in the range of 700 ° C. and 950 ° C. for 20 s to 10 min. A method for producing an austenitic stainless steel sheet, which comprises applying and finally subjecting a dilute nitric acid electrolytic treatment.
[5] The dilute nitric acid electrolysis treatment involves a total of cathode and anode electrolysis at a current density of ± 10 to 80 mA / cm 2 in a dilute nitric acid aqueous solution having a nitric acid concentration of 3 to 10% and a temperature of 30 to 65 ° C. The method for producing an austenitic stainless steel plate according to [4], which comprises a treatment performed for 10 to 60 s.
本発明によれば、表面の孔食発生電位が高くなり、耐孔食性に優れたステンレス鋼板とすることができ、産業上格段の効果を奏する。また、本発明によれば、例えば、孔食指数の低い鋼板であっても、従来では対応できなかったような腐食環境下において、適用可能となるという効果もある。 According to the present invention, the potential for pitting corrosion on the surface is increased, and a stainless steel sheet having excellent pitting corrosion resistance can be obtained, which is extremely effective in industry. Further, according to the present invention, for example, even a steel sheet having a low pitting corrosion index can be applied in a corrosive environment that cannot be dealt with in the past.
本発明は、オーステナイト系ステンレス鋼板で、質量％で、
C：0.40％以下、 Si：1.00％以下、
Mn：2.00％以下、 P：0.045％以下、
S：0.030％以下、 Ni：3.5～20.0％、
Cr：15.00～30.00％、 Mo：0～3.5％、
N：0.30％以下
を含有し、かつCr、MoをＸ＝Cr＋3.3Moが15.0～40.0を満足するように含み、残部Feおよび不可避的不純物からなる組成を有する。以下、組成に係る質量％は、単に％で記す。
The present invention is an austenitic stainless steel sheet, in mass%.
C: 0.40% or less, Si: 1.00% or less,
Mn: 2.00% or less, P: 0.045% or less,
S: 0.030% or less, Ni: 3.5-20.0%,
Cr: 15.00 to 30.00%, Mo: 0 to 3.5%,
N: Contains 0.30% or less, contains Cr and Mo so that X = Cr + 3.3Mo satisfies 15.0 to 40.0, and has a composition consisting of the balance Fe and unavoidable impurities. Hereinafter, the mass% related to the composition is simply expressed as%.
まず、組成の限定理由について説明する。 First, the reason for limiting the composition will be described.
C：0.40％以下
Cは、少量の含有で、強度等の機械的特性や耐摩耗性を向上させる元素である。このような効果を得るためには、0.001％以上含有することが好ましい。一方、0.40％超えて含有すると、結晶粒界にCr炭化物が生成しやすくなり、粒界腐食の発生を招きやすい。さらに0.40％を超える含有は、延性を低下させプレス加工性を阻害する。このため、Cは0.40％以下に限定した。なお、好ましくは0.01～0.20％である。
C: 0.40% or less
C is an element that improves mechanical properties such as strength and wear resistance when contained in a small amount. In order to obtain such an effect, it is preferably contained in an amount of 0.001% or more. On the other hand, if the content exceeds 0.40%, Cr carbides are likely to be generated at the grain boundaries, which tends to cause intergranular corrosion. Further, a content of more than 0.40% lowers ductility and impairs press workability. Therefore, C was limited to 0.40% or less. It is preferably 0.01 to 0.20%.
Si：1.00％以下
Siは、溶鋼の脱酸剤として作用するとともに、弾性限や引張強さ等の強度増加に寄与する元素である。このような効果を得るためには、Siは0.10％以上含有することが好ましい。一方、1.00％を超えて含有すると、熱間圧延時に耳割れが発生し製品歩留りを低下させる。このため、Siは1.00％以下に限定した。なお、SiO2は還元性雰囲気中でも生成する酸化物で、ごく薄いSiO2は耐食性向上に非常に有効に働くことがある。SiO2は、硝酸電解によっても溶解せず、耐食性を上げる効果を有している。
Si: 1.00% or less
Si is an element that acts as a deoxidizing agent for molten steel and contributes to an increase in strength such as elastic limit and tensile strength. In order to obtain such an effect, it is preferable that Si is contained in an amount of 0.10% or more. On the other hand, if it is contained in excess of 1.00%, ear cracks occur during hot rolling and the product yield is lowered. Therefore, Si was limited to 1.00% or less. It should be noted that SiO 2 is an oxide produced even in a reducing atmosphere, and very thin SiO 2 may work very effectively for improving corrosion resistance. SiO 2 does not dissolve even by nitric acid electrolysis and has the effect of increasing corrosion resistance.
Mn：2.00％以下
Mnは、引張強さ等の強度増加や靭性向上に寄与するとともに、溶鋼の脱酸に有効に作用する元素である。このような効果を得るためには0.10％以上含有することが好ましい。一方、2.00％を超えて含有すると、鋼中にMnS等の介在物が増加し、加工性に悪影響を及ぼす。さらに、これら介在物は孔食の起点にもなりやすく、耐孔食性に悪影響を及ぼすため、Mnは2.00％以下に限定した。
Mn: 2.00% or less
Mn is an element that contributes to increasing strength such as tensile strength and improving toughness, and also effectively acts on deoxidation of molten steel. In order to obtain such an effect, it is preferably contained in an amount of 0.10% or more. On the other hand, if it is contained in excess of 2.00%, inclusions such as MnS increase in the steel, which adversely affects workability. Furthermore, since these inclusions are likely to be the starting point of pitting corrosion and adversely affect pitting corrosion resistance, Mn was limited to 2.00% or less.
P：0.045％以下、S：0.030％以下
P、Sは、鋼中に不可避的に存在し、機械的特性に悪影響を及ぼす元素である。このため、P、Sは、できるだけ低減することが望ましいが、Pは0.045％までの含有、Sは0.030％までの含有であれば、実用的に問題はなく、許容できる。このため、P：0.045％以下、S：0.030％以下にそれぞれ限定した。
P: 0.045% or less, S: 0.030% or less
P and S are elements that are inevitably present in steel and adversely affect mechanical properties. Therefore, it is desirable to reduce P and S as much as possible, but if P is contained up to 0.045% and S is contained up to 0.030%, there is no practical problem and it is acceptable. Therefore, it was limited to P: 0.045% or less and S: 0.030% or less.
Ni：3.5～20.0％
Niは、耐食性の向上や、靱性、強度、耐熱性の向上にも寄与する元素である。このような効果を得るためには、3.5％以上の含有を必要とする。3.5％未満の含有では、室温での組織がフェライト相となる。一方、20.0％を超えて含有すると、加工性が低下し、また溶接性も低下する。このため、Niは3.5～20.0％の範囲に限定した。
Ni: 3.5-20.0%
Ni is an element that contributes to the improvement of corrosion resistance, toughness, strength, and heat resistance. In order to obtain such an effect, the content of 3.5% or more is required. If the content is less than 3.5%, the structure at room temperature becomes a ferrite phase. On the other hand, if it is contained in excess of 20.0%, the workability is lowered and the weldability is also lowered. Therefore, Ni was limited to the range of 3.5 to 20.0%.
Cr：15.00～30.00％
Crは、Niとともに、耐食性の向上に寄与し、さらにNiとともに、室温での組織をオーステナイト相とする。このような効果を得るためには、Crは15.00％以上の含有を必要とする。一方、30.00％を超えて含有すると、延性が低下するとともに、材料コストの高騰を招く。このため、Crは15.00～30.00％の範囲に限定した。なお、好ましくは16.00～30.00％である。
Cr: 15.00-30.00%
Cr, together with Ni, contributes to the improvement of corrosion resistance, and together with Ni, makes the structure at room temperature an austenite phase. In order to obtain such an effect, Cr must be contained in an amount of 15.00% or more. On the other hand, if it is contained in excess of 30.00%, the ductility is lowered and the material cost is increased. Therefore, Cr was limited to the range of 15.00 to 30.00%. It is preferably 16.00 to 30.00%.
Mo：0～3.5％
Moは、耐孔食性の向上に寄与するとともに、機械的特性の向上にも寄与する元素であり0％を含み、必要に応じて含有できる。このような効果を得るために含有する場合は、0.001％以上含有することが好ましい。Moの含有量が0.001％未満では、機械的特性が若干低下する。一方、3.5％を超える含有は、加工性が若干低下する。このため、含有する場合には、Moは3.5％以下に限定した。なお、好ましくは0.5～3.0％である。
Mo: 0-3.5%
Mo is an element that contributes to the improvement of pitting corrosion resistance and also to the improvement of mechanical properties, and contains 0%, and can be contained as needed. When it is contained in order to obtain such an effect, it is preferably contained in an amount of 0.001% or more. If the Mo content is less than 0.001%, the mechanical properties will be slightly reduced. On the other hand, if the content exceeds 3.5%, the processability is slightly lowered. Therefore, when it is contained, Mo is limited to 3.5% or less. It is preferably 0.5 to 3.0%.
N：0.30％以下
Nは、オーステナイト相を安定化させるとともに、侵入型に固溶して固溶強化により強度増加に寄与する元素である。このような効果を得るためには、0.01％以上含有することが好ましい。一方、0.30％を超えて含有すると、高温割れの助長、二次加工性の低下、粒界腐食の促進などの悪影響を及ぼす。このため、Nは0.30％以下に限定した。なお、好ましくは0.20％以下、より好ましくは0.01～0.10％である。
N: 0.30% or less
N is an element that stabilizes the austenite phase and dissolves in an intrusive form to contribute to the increase in strength by strengthening the solid solution. In order to obtain such an effect, it is preferably contained in an amount of 0.01% or more. On the other hand, if it is contained in excess of 0.30%, it has adverse effects such as promotion of high temperature cracking, deterioration of secondary workability, and promotion of intergranular corrosion. Therefore, N was limited to 0.30% or less. It is preferably 0.20% or less, more preferably 0.01 to 0.10%.
Ｘ：15.0～40.0
次（２）式
Ｘ＝Cr＋3.3Mo……（２）
ここで、Cr、Mo：各元素の含有量（質量％）
で定義される孔食指数Ｘが15.0未満であると、希硝酸電解処理と冷間圧延後の熱処理とを組み合わせても、孔食発生電位の増加が認められない。一方、Ｘが40.0を超えると、希硝酸電解処理と冷間圧延後の熱処理とを組み合わせても、孔食発生電位の増加効果が認められなくなる。このため、Ｘは15.0～40.0の範囲に限定した。
X: 15.0-40.0
Next (2) Equation X = Cr + 3.3Mo …… (2)
Here, Cr, Mo: content of each element (mass%)
When the pitting corrosion index X defined in is less than 15.0, no increase in the pitting corrosion potential is observed even when the dilute nitric acid electrolysis treatment and the heat treatment after cold rolling are combined. On the other hand, when X exceeds 40.0, the effect of increasing the pitting corrosion potential cannot be recognized even if the dilute nitric acid electrolysis treatment and the heat treatment after cold rolling are combined. Therefore, X is limited to the range of 15.0 to 40.0.
上記した成分が基本の成分であるが、本発明では、上記した基本の成分に加えてさらに、選択元素として、必要に応じて、Ti：0.01～1.00％、Nb：0.01～1.00％、Cu：0.01～3.00％、Al：0.0001～1.50％、Ca：0.001～0.01％、Mg：0.001～0.01％、V：0.01～1.00％、Co：0.01～0.5％、W：0.01～1.0％、B:0.001～0.01％のうちから選ばれた１種または２種以上を含有してもよい。 The above-mentioned components are the basic components, but in the present invention, in addition to the above-mentioned basic components, as a selective element, Ti: 0.01 to 1.00%, Nb: 0.01 to 1.00%, Cu: as required. 0.01 to 3.00%, Al: 0.0001 to 1.50%, Ca: 0.001 to 0.01%, Mg: 0.001 to 0.01%, V: 0.01 to 1.00%, Co: 0.01 to 0.5%, W: 0.01 to 1.0%, B: 0.001 It may contain one or more selected from ~ 0.01%.
Ti：0.01～1.00％、Nb：0.01～1.00％、Cu：0.01～3.00％、Al：0.0001～1.50％、Ca：0.001～0.01％、Mg：0.001～0.01％、V：0.01～1.00％、Co：0.01～0.5％、W：0.01～1.0％、B：0.001～0.01％のうちから選ばれた１種または２種以上
Ti、Nb、Cu、Al、Ca、Mg、V、Co、W、Bはいずれも、鋼中に微細析出物として分散することにより、鋼板の強度上昇、耐食性向上に寄与する元素であり、また、Bは高温特性の改善に効果があり、必要に応じて選択して１種または２種以上を含有できる。このような効果を得るためには、Ti：0.01％以上、Nb：0.01％以上、Cu：0.01％以上、Al：0.0001％以上、Ca：0.001％以上、Mg：0.001％以上、V：0.01％以上、Co：0.01％以上、W：0.01％以上、B：0.001％以上をそれぞれ含有する必要がある。一方、Ti：1.00％、Nb：1.00％、Cu：3.00％、Al：1.50％、Ca：0.01％、Mg：0.01％、V：1.00％、Co：0.5％、W：1.0％、B：0.01％をそれぞれ超えて含有すると、析出物の生成量が多くなり、耐食性の低下や伸びの低下を招きやすくなる。このため、含有する場合には、Ti：0.01～1.00％、Nb：0.01～1.00％、Cu：0.01～3.00％、Al：0.0001～1.50％、Ca：0.001～0.01％、Mg：0.001～0.01％、V：0.01～1.00％、Co：0.01～0.5％、W：0.01～1.0％、B:0.001～0.01％の範囲にそれぞれ限定することが好ましい。
Ti: 0.01 to 1.00%, Nb: 0.01 to 1.00%, Cu: 0.01 to 3.00%, Al: 0.0001 to 1.50%, Ca: 0.001 to 0.01%, Mg: 0.001 to 0.01%, V: 0.01 to 1.00%, Co : 0.01 to 0.5%, W: 0.01 to 1.0%, B: 0.001 to 0.01%, one or more selected
Ti, Nb, Cu, Al, Ca, Mg, V, Co, W, and B are all elements that contribute to increasing the strength and corrosion resistance of steel sheets by dispersing them as fine precipitates in steel. , B is effective in improving high temperature characteristics, and can be selected and contained in one or more types as needed. In order to obtain such an effect, Ti: 0.01% or more, Nb: 0.01% or more, Cu: 0.01% or more, Al: 0.0001% or more, Ca: 0.001% or more, Mg: 0.001% or more, V: 0.01% As mentioned above, it is necessary to contain Co: 0.01% or more, W: 0.01% or more, and B: 0.001% or more, respectively. On the other hand, Ti: 1.00%, Nb: 1.00%, Cu: 3.00%, Al: 1.50%, Ca: 0.01%, Mg: 0.01%, V: 1.00%, Co: 0.5%, W: 1.0%, B: 0.01 If it is contained in excess of%, the amount of precipitates produced increases, which tends to cause a decrease in corrosion resistance and a decrease in elongation. Therefore, when it is contained, Ti: 0.01 to 1.00%, Nb: 0.01 to 1.00%, Cu: 0.01 to 3.00%, Al: 0.0001 to 1.50%, Ca: 0.001 to 0.01%, Mg: 0.001 to 0.01%. , V: 0.01 to 1.00%, Co: 0.01 to 0.5%, W: 0.01 to 1.0%, B: 0.001 to 0.01%, respectively.
上記した成分以外の残部は、Feおよび不可避的不純物からなる。 The rest other than the above components consist of Fe and unavoidable impurities.
なお、O（酸素）は、不可避的に含有され、鋼中では酸化物として存在し、延性、靭性等に悪影響を及ぼす。そのため、O（酸素）は、不純物としてできるだけ低減することが好ましいが、0.010％までは許容できる。なお、0.001％未満の過剰な低減は精錬コストを高騰させるため、O（酸素）は、0.001％以上とすることが好ましい。 O (oxygen) is inevitably contained and exists as an oxide in steel, which adversely affects the ductility, toughness, and the like. Therefore, it is preferable to reduce O (oxygen) as an impurity as much as possible, but up to 0.010% is acceptable. It is preferable that O (oxygen) is 0.001% or more because an excessive reduction of less than 0.001% raises the refining cost.
本発明オーステナイト系ステンレス鋼板は、上記した組成を有し、かつ次（１）式
Ｖｃ ＞ －0.006Ｘ3－0.35Ｘ2＋63Ｘ－646 ……（１）
ここで、Ｘ＝Cr＋3.3Mo……（２）
Cr、Mo：各元素の含有量（質量％）
を満足する表面の孔食発生電位Ｖｃを有する。測定された鋼板表面の孔食発生電位Ｖｃが低く、（１）式を満足しない場合には、所望の耐孔食性を確保できなくなる。なお、本発明鋼板表面の孔食発生電位Ｖｃは、次（３）式
Ｖｃ ＜ 0.039Ｘ3－5.2Ｘ2＋232Ｘ－2311 ……（３）
ここで、Ｘ＝Cr＋3.3Mo……（２）
Cr、Mo：各元素の含有量（質量％）
を満足する。本発明オーステナイト系ステンレス鋼板では、上記した（３）式を満足しなくなるまでの、鋼板表面の孔食発生電位Ｖcの向上、すなわち耐食性の向上は得られないことを確認している。
The austenitic stainless steel sheet of the present invention has the above-mentioned composition and has the following formula (1).
Vc> -0.006X 3 -0.35X 2 + 63X-646 …… (1)
Here, X = Cr + 3.3Mo …… (2)
Cr, Mo: Content of each element (mass%)
It has a pitting corrosion potential Vc on the surface that satisfies the above. If the measured pitting corrosion potential Vc on the surface of the steel sheet is low and the equation (1) is not satisfied, the desired pitting corrosion resistance cannot be ensured. The pitting corrosion potential Vc on the surface of the steel sheet of the present invention is calculated by the following equation (3).
Vc <0.039X3 -5.2X2 + 232X-2311 …… ( 3 )
Here, X = Cr + 3.3Mo …… (2)
Cr, Mo: Content of each element (mass%)
To be satisfied. It has been confirmed that the austenitic stainless steel sheet of the present invention cannot improve the pitting corrosion potential Vc on the surface of the steel sheet, that is, improve the corrosion resistance, until the above equation (3) is not satisfied.
ここで、鋼板表面の孔食発生電位Ｖｃは、表層を研磨しないサンプルを用いて、JIS G 0577の規定に準拠して測定した値を用いるものとする。照合電極はAg/AgCl電極とする。なお、測定に当たっては、試験溶液（塩化ナトリウム水溶液）の脱気は行わないものとする。 Here, the pitting corrosion potential Vc on the surface of the steel sheet shall be a value measured in accordance with the provisions of JIS G 0577 using a sample in which the surface layer is not polished. The reference electrode is an Ag / AgCl electrode. In the measurement, the test solution (sodium chloride aqueous solution) shall not be degassed.
つぎに、本発明のオーステナイト系ステンレス鋼板の好ましい製造方法について説明する。 Next, a preferable manufacturing method of the austenitic stainless steel sheet of the present invention will be described.
本発明では、上記した組成を有し、焼鈍および酸洗済みの熱延鋼板に、１回又は複数回の冷間圧延を施して、所定板厚の冷延鋼板とする。その際、本発明では、複数回の冷間圧延のうちの最終の冷間圧延の後に熱処理を施し、工程の最終として、希硝酸電解処理を施す。これにより、図１に示すように、希硝酸電解処理前の孔食発生電位（〇印）に比べて、孔食発生電位（●印）が高くなり、耐孔食性がさらに向上する。 In the present invention, a hot-rolled steel sheet having the above-mentioned composition and having been annealed and pickled is subjected to cold rolling once or a plurality of times to obtain a cold-rolled steel sheet having a predetermined plate thickness. At that time, in the present invention, heat treatment is performed after the final cold rolling among a plurality of cold rollings, and dilute nitric acid electrolysis treatment is performed as the final step. As a result, as shown in FIG. 1, the pitting corrosion potential (marked with ●) is higher than the pitting corrosion potential (marked with ◯) before the dilute nitric acid electrolysis treatment, and the pitting corrosion resistance is further improved.
上記した本発明鋼板の製造に好適な熱処理としては、軟化及び合金元素等の固溶化を目的とした熱処理である、700℃超え950℃以下の範囲の温度で20ｓ～10min保持する熱処理とすることが好ましい。熱処理温度が、700℃以下では、軟化および合金元素等の固溶化が不十分となり、一方、950℃超えでは、窒化層やCr欠乏層の成長が大きくなるため、それらをその後の電解処理で除去するために、電解処理液の酸濃度を高め、電気量を高める必要がある。そのような電解処理を行うと、表面肌が大きく変化する。このため、熱処理温度は700℃超え950℃以下の範囲の温度に限定することが好ましい。また、上記した温度範囲での保持時間が、20ｓ未満では、軟化および合金元素等の固溶化が不十分となり、一方、10min超えて長くなると、結晶粒の粗大化が著しくなるとともに、窒化層やCr欠乏層の成長が大きくなるため、それらをその後の電解処理で除去するには、電解処理液の酸濃度を高め、電気量を高める必要がある。そのような電解処理を行うと、表面肌が大きく変化する。このため、上記した温度範囲での保持時間は20ｓ～10minの範囲に限定することが好ましい。 The heat treatment suitable for the production of the steel sheet of the present invention described above is a heat treatment for the purpose of softening and solidification of alloying elements, etc., which is a heat treatment for holding 20 s to 10 min at a temperature in the range of 700 ° C. or higher and 950 ° C. or lower. Is preferable. When the heat treatment temperature is 700 ° C or lower, softening and solidification of alloying elements are insufficient, while when the heat treatment temperature exceeds 950 ° C, the growth of the nitrided layer and the Cr-deficient layer increases, and these are removed by the subsequent electrolytic treatment. Therefore, it is necessary to increase the acid concentration of the electrolytic treatment liquid and increase the amount of electricity. When such an electrolytic treatment is performed, the surface skin is significantly changed. Therefore, it is preferable to limit the heat treatment temperature to a temperature in the range of more than 700 ° C and not more than 950 ° C. Further, if the holding time in the above temperature range is less than 20 s, softening and solid dissolution of alloying elements, etc. are insufficient, while if it is longer than 10 min, the coarsening of crystal grains becomes remarkable and the nitrided layer or Since the growth of the Cr-deficient layer becomes large, it is necessary to increase the acid concentration of the electrolytic treatment liquid and increase the amount of electricity in order to remove them by the subsequent electrolytic treatment. When such an electrolytic treatment is performed, the surface skin is significantly changed. Therefore, the holding time in the above temperature range is preferably limited to the range of 20 s to 10 min.
なお、本発明では、焼鈍雰囲気条件にとくに限定はなく、大気雰囲気下での焼鈍には限定されない。例えば、焼鈍を燃料と酸素を含む燃焼ガス雰囲気で行っても問題はない。この際の焼鈍時の酸素濃度は、昇温中の750℃までは3～15％が望ましく、露点として30～60℃までが好ましい。また、焼鈍は水素を含有した還元性雰囲気下における光輝焼鈍（BA焼鈍と呼称される場合もある。）を行ってもよい。光輝焼鈍を行う場合は、100％水素、あるいはアンモニア分解ガスを含む雰囲気中で行ってもよい。還元性雰囲気下での焼鈍では、窒素含有量が20～60体積％（好ましくは窒素50体積％以下）かつ水素を5体積％以上（好ましくは20体積％以上、90体積％以下）含有した混合ガスを用いることが好ましい。また、焼鈍時の雰囲気露点は-20℃以下（好ましくは-40℃以下）とすることが好ましい。とくに750℃～最終到達温度までは-55℃以下であることが望ましい。 In the present invention, the annealing atmosphere conditions are not particularly limited, and the annealing is not limited to the annealing atmosphere. For example, there is no problem even if annealing is performed in a combustion gas atmosphere containing fuel and oxygen. At this time, the oxygen concentration at the time of annealing is preferably 3 to 15% up to 750 ° C. during temperature rise, and preferably 30 to 60 ° C. as a dew point. Further, the annealing may be performed by bright annealing (sometimes referred to as BA annealing) in a reducing atmosphere containing hydrogen. When performing bright annealing, it may be performed in an atmosphere containing 100% hydrogen or an ammonia decomposition gas. For quenching in a reducing atmosphere, a mixture containing 20 to 60% by volume of nitrogen (preferably 50% by volume or less of nitrogen) and 5% by volume or more of hydrogen (preferably 20% by volume or more and 90% by volume or less). It is preferable to use gas. The atmospheric dew point during annealing is preferably -20 ° C or lower (preferably -40 ° C or lower). In particular, it is desirable that the temperature is -55 ° C or lower from 750 ° C to the final temperature.
本発明では、上記した冷間圧延および熱処理を施し、最終に、希硝酸電解処理を施す。 In the present invention, the above-mentioned cold rolling and heat treatment are performed, and finally, dilute nitric acid electrolysis treatment is performed.
希硝酸電解処理としては、硝酸濃度：3～10％、温度：30～65℃の希硝酸水溶液中で、電流密度：±10～80mA/cm2で、陰極・陽極電解を合計で10～60ｓ行う処理とすることが好ましい。 For dilute nitric acid electrolysis treatment, in a dilute nitric acid aqueous solution with a nitric acid concentration of 3 to 10% and a temperature of 30 to 65 ° C, a current density of ± 10 to 80 mA / cm 2 and a total of 10 to 60 s for cathode and anode electrolysis. It is preferable to carry out the treatment.
硝酸濃度が3％未満では、希硝酸電解処理の効果が不足し、一方、10％を超えると、鋼板表層の溶解が著しくなり、NOxの発生が激しくなり環境に好ましくない。このため、希硝酸水溶液の硝酸濃度は3～10％に限定した。また、希硝酸水溶液の温度が、30℃未満では希硝酸電解の効果が不足し、一方、65℃を超えると、鋼板表層の溶解が著しくなる。このため、希硝酸水溶液の温度は30～65℃の範囲に限定した。また、電流密度が、10mA/cm2未満では希硝酸電解の効果が不足し、一方、80mA/cm2を超えて大きくなると、表層の溶解が大きくなりすぎる。このため、電流密度は10～80mA/cm2の範囲に限定した。また、電解時間が合計で10ｓ未満では希硝酸電解の効果が不足し、一方、60ｓを超えて長くなると溶解量が大きくなりすぎる。このため、電解時間は陰極・陽極電解の合計で10～60ｓの範囲に限定した。電解は間接電解で、鋼板側がアノード、カソードとなるような順番で行った。 If the nitric acid concentration is less than 3%, the effect of the dilute nitric acid electrolysis treatment is insufficient, while if it exceeds 10%, the surface layer of the steel sheet is significantly dissolved and NOx is generated violently, which is not preferable for the environment. Therefore, the nitric acid concentration of the dilute nitric acid aqueous solution was limited to 3 to 10%. Further, when the temperature of the dilute nitric acid aqueous solution is less than 30 ° C., the effect of dilute nitric acid electrolysis is insufficient, while when it exceeds 65 ° C., the melting of the surface layer of the steel sheet becomes remarkable. Therefore, the temperature of the dilute nitric acid aqueous solution was limited to the range of 30 to 65 ° C. Further, when the current density is less than 10 mA / cm 2 , the effect of dilute nitric acid electrolysis is insufficient, while when it is larger than 80 mA / cm 2 , the dissolution of the surface layer becomes too large. Therefore, the current density was limited to the range of 10 to 80 mA / cm 2 . Further, if the total electrolysis time is less than 10 s, the effect of dilute nitric acid electrolysis is insufficient, while if it is longer than 60 s, the amount of dissolution becomes too large. Therefore, the electrolysis time was limited to the range of 10 to 60 s in total for cathode and anode electrolysis. The electrolysis was indirect electrolysis, and the electrolysis was performed in the order of the anode and the cathode on the steel plate side.
なお、上記した希硝酸電解処理であれば、光沢感のある表面肌を得ることができる。その場合、面粗さSaは0.80μm以下である。面粗さSaが0.80μmを超えて粗くなると、光沢感のある表面肌とすることができない。本発明では面粗さをSaで0.80μm以下とする。なお、面粗さはISO 25178の規定に準拠して測定された算術平均高さSaを用いるものとする。 With the above-mentioned dilute nitric acid electrolysis treatment, a glossy surface skin can be obtained. In that case, the surface roughness Sa is 0.80 μm or less. If the surface roughness Sa exceeds 0.80 μm and becomes rough, it is not possible to obtain a glossy surface surface. In the present invention, the surface roughness is 0.80 μm or less in Sa. For the surface roughness, the arithmetic mean height Sa measured in accordance with the regulations of ISO 25178 shall be used.
上記した製造方法により製造された冷延鋼板の耐孔食性が向上する理由は、以下のような現象が起きているためであると考えられる。 It is considered that the reason why the pitting corrosion resistance of the cold-rolled steel sheet manufactured by the above-mentioned manufacturing method is improved is that the following phenomena occur.
冷延鋼板に熱処理を施すと、Crが鋼板表面に向かって拡散し、一部は表面からガス成分として炉内に蒸発するが、鋼板表面に近づくにしたがい濃度が高くなり、Cr濃化層が形成される。一方、最表層には、熱処理中に窒化層や酸化層（被膜）が形成される。これらの層が、希硝酸電解処理により除去されることにより、Cr濃化層が現われ、耐孔食性が向上する。 When the cold-rolled steel sheet is heat-treated, Cr diffuses toward the surface of the steel sheet, and part of it evaporates from the surface into the furnace as a gas component. It is formed. On the other hand, a nitrided layer and an oxide layer (coating) are formed on the outermost layer during the heat treatment. By removing these layers by dilute nitric acid electrolysis treatment, a Cr-concentrated layer appears and pitting corrosion resistance is improved.
Crは、O（酸素）やNといったガス成分との親和力が強い。そのため、Crは熱処理中に、雰囲気ガスと接触している表面近傍に濃化すると考えられる。濃化したCrは、雰囲気から侵入したO、N、Cと、あるいは鋼中に存在するO、N、Cと、結びつき、Cr析出物を形成する。Cr析出物が形成されると、母相中に固溶したCr量（固溶Cr量）が減少すると考えられる。Crによる耐食性の向上は固溶Cr量に由来するため、固溶Cr量の減少は、鋼板自体の耐食性の低下を招く。また、Cr析出物が形成されると、表層にCrが拡散してくるため、その内側にCr欠乏層が生成する。 Cr has a strong affinity for gas components such as O (oxygen) and N. Therefore, it is considered that Cr is concentrated in the vicinity of the surface in contact with the atmospheric gas during the heat treatment. The concentrated Cr binds to O, N, C invading from the atmosphere or O, N, C existing in the steel to form a Cr precipitate. When Cr precipitates are formed, it is considered that the amount of Cr dissolved in the matrix (solid solution Cr amount) decreases. Since the improvement in corrosion resistance due to Cr is derived from the amount of solid solution Cr, a decrease in the amount of solid solution Cr leads to a decrease in the corrosion resistance of the steel sheet itself. Further, when a Cr precipitate is formed, Cr diffuses into the surface layer, so that a Cr-deficient layer is formed inside the Cr precipitate.
例えば、950℃超えに加熱する通常の焼鈍（熱処理）では、上記したCr欠乏層の厚さが厚くなり、鋼板表面近傍の耐食性を低下させることがある。一方、本発明におけるような、700℃超え950℃以下の焼鈍（熱処理）では、Crの欠乏量は950℃超えの温度に加熱する通常の焼鈍より少なく、耐食性が損なわれることはより少ないものと考えられる。むしろ、表面近傍におけるC欠乏層の形成により、析出が生じた最表面の内側では、Cr炭化物などの析出が抑制され、有効Cr量（固溶Cr量）が増加することが考えられる。本発明では、熱処理により最表層に生成したCr析出物を含む層及びCr酸化物を、希硝酸電解処理で除去するため、その内側に存在するCr析出物が少ない耐食性に優れる部分が露出し、鋼板表面の耐食性が向上すると、考えられる。 For example, in normal annealing (heat treatment) in which the material is heated to above 950 ° C., the thickness of the Cr-deficient layer described above may increase, and the corrosion resistance in the vicinity of the surface of the steel sheet may decrease. On the other hand, in annealing (heat treatment) of 700 ° C. or higher and 950 ° C. or lower as in the present invention, the amount of Cr deficiency is less than that of normal annealing heated to a temperature of 950 ° C. or higher, and the corrosion resistance is less impaired. Conceivable. Rather, it is considered that the formation of the C-deficient layer in the vicinity of the surface suppresses the precipitation of Cr carbides and the like inside the outermost surface where the precipitation occurs, and the effective Cr amount (solid solution Cr amount) increases. In the present invention, since the layer containing the Cr precipitate and the Cr oxide generated on the outermost surface layer by the heat treatment are removed by the dilute nitrate electrolysis treatment, the portion having a small amount of Cr precipitate inside and having excellent corrosion resistance is exposed. It is considered that the corrosion resistance of the surface of the steel sheet is improved.
Crは酸化しやすく表面にCr酸化膜を形成するため、鋼板の表面近傍ではCrが減少する。同時に、表面近傍では、CrがO（酸素）、Cなどと結びつき、微細なCr酸化物やCr炭化物等として表面直下の鋼板側に析出する。Cr析出物が析出することにより、その部分での有効Cr量（固溶Cr量）が減少し、耐食性が低下する。また、Cr炭化物が形成された部分の近傍では、C濃度が減少しC欠乏層が形成されることが考えられる。 Since Cr is easily oxidized and forms a Cr oxide film on the surface, Cr decreases near the surface of the steel sheet. At the same time, in the vicinity of the surface, Cr binds to O (oxygen), C, etc., and precipitates as fine Cr oxides, Cr carbides, etc. on the steel sheet side directly below the surface. When the Cr precipitate is deposited, the effective Cr amount (solid solution Cr amount) at that portion is reduced, and the corrosion resistance is lowered. Further, it is considered that the C concentration decreases and a C-deficient layer is formed in the vicinity of the portion where the Cr carbide is formed.
例えば、950℃超えの温度に加熱する通常の焼鈍（熱処理）では、上記した鋼板最表層の脱炭や、Cr酸化層の形成、さらに表面近傍におけるCr析出物の生成が著しくなる。脱炭等によるCの減少は、有効Cr量を増加させるという観点からは、耐食性向上に有利に作用するとも考えられるが、Cr酸化層の形成に伴う脱Cr層の形成や、表面近傍におけるCr析出物の生成は、表面近傍における有効Cr量を減少させ、耐食性を低下させる。 For example, in the usual annealing (heat treatment) of heating to a temperature exceeding 950 ° C., the decarburization of the outermost surface layer of the steel sheet, the formation of the Cr oxide layer, and the formation of Cr precipitates in the vicinity of the surface become remarkable. A decrease in C due to decarburization or the like is considered to have an advantageous effect on improving corrosion resistance from the viewpoint of increasing the amount of effective Cr, but the formation of a deCr layer accompanying the formation of a Cr oxide layer and Cr in the vicinity of the surface The formation of precipitates reduces the amount of effective Cr in the vicinity of the surface and reduces corrosion resistance.
一方、本発明におけるような700℃超え950℃以下の低温での熱処理においては、速度は遅いが、同様の現象が生じていると考えられる。しかし、700℃超え950℃以下の低温での熱処理では、950℃超えの温度での熱処理に比べてCrの拡散速度は遅く、また、Cr酸化物の生成も少ないため、脱Cr層の形成による耐食性低下の影響は少ないと考えられる。一方、表面近傍でのCr炭化物の生成により、その近傍での母相中のC濃度は減少する。しかし、Cの拡散速度が十分に速くないため、それを補うのに必要なCの拡散供給が間に合わず、Cが減少したCの欠乏層（C欠乏層）が形成されることが考えられる。C欠乏層の形成により、その部分の有効Cr量が増加し、耐食性が向上することが予想される。本発明では、最表層に形成したCr析出物を含む層を希硝酸電解処理により除去するため、耐食性が向上したC欠乏層が表面に露出し、結果として鋼板の耐食性が向上すると考えられる。 On the other hand, in the heat treatment at a low temperature of more than 700 ° C. and 950 ° C. or less as in the present invention, the speed is slow, but it is considered that the same phenomenon occurs. However, in the heat treatment at a low temperature of over 700 ° C and below 950 ° C, the diffusion rate of Cr is slower than that of the heat treatment at a temperature of over 950 ° C, and the formation of Cr oxide is small. It is considered that the effect of deterioration of corrosion resistance is small. On the other hand, the formation of Cr carbide near the surface reduces the C concentration in the matrix in the vicinity. However, since the diffusion rate of C is not sufficiently fast, it is conceivable that the diffusion supply of C required to supplement it is not in time, and a C-depleted layer (C-deficient layer) in which C is reduced is formed. It is expected that the formation of the C-deficient layer will increase the effective Cr amount in that region and improve the corrosion resistance. In the present invention, since the layer containing the Cr precipitate formed on the outermost surface layer is removed by the dilute nitric acid electrolytic treatment, it is considered that the C-deficient layer having improved corrosion resistance is exposed on the surface, and as a result, the corrosion resistance of the steel sheet is improved.
上記したように、表面近傍に存在するCは、熱処理中、表面で雰囲気中のO（酸素）と結びつき、ガス成分として蒸発するか、あるいは表面近傍に存在するCrと結びつき、Cr炭化物として析出するため、表面近傍ではC量が減少し、それに伴い有効Cr量が増加する。雰囲気中のガス成分との反応に伴う鋼板中Cの蒸発は、C量の低い鋼板に比べて、C量の高い鋼板で多くなると考えられる。このため、C量の高い鋼板の方が、熱処理によるC量減少に伴う有効Cr量の変化（増加）が大きくなり、本発明では、熱処理後の希硝酸電解処理による耐食性改善効果が高C鋼板で著しくなるものと考えられる。 As described above, C existing near the surface binds to O (oxygen) in the atmosphere on the surface during heat treatment and evaporates as a gas component, or binds to Cr existing near the surface and precipitates as Cr carbide. Therefore, the amount of C decreases near the surface, and the amount of effective Cr increases accordingly. It is considered that the evaporation of C in the steel sheet due to the reaction with the gas component in the atmosphere is larger in the steel sheet having a high C content than in the steel sheet having a low C content. Therefore, the steel sheet having a high C amount has a larger change (increase) in the effective Cr amount due to the decrease in the C amount due to the heat treatment. It is thought that it will be remarkable.
また、Moも、Crと同様、固溶状態となることで鋼板の耐食性（耐孔食性）向上に寄与する。すなわち、有効Mo量（固溶Mo量）が多くなることで、不動態被膜を強固にし、鋼板の耐食性（耐孔食性）を改善する。また、Moも、Crと同様にCと結合しやすいため、熱処理中に、表面近傍で鋼中Cのガス化が生じると、表面近傍での有効Mo量が増加することになる。この有効Mo量の増加は、Mo含有量が多いほど多くなることから、Mo含有量の多い鋼板ほど耐孔食性の向上効果が大きくなるものと考えられる。 In addition, Mo also contributes to the improvement of corrosion resistance (pitting corrosion resistance) of the steel sheet by being in a solid solution state like Cr. That is, by increasing the effective Mo amount (solid solution Mo amount), the passivation film is strengthened and the corrosion resistance (pitting corrosion resistance) of the steel sheet is improved. Further, since Mo also easily binds to C like Cr, if gasification of C in the steel occurs in the vicinity of the surface during the heat treatment, the effective amount of Mo in the vicinity of the surface increases. Since this increase in the effective Mo content increases as the Mo content increases, it is considered that the steel sheet having a higher Mo content has a greater effect of improving the pitting corrosion resistance.
以下、実施例に基づき、さらに本発明について説明する。 Hereinafter, the present invention will be further described based on Examples.
（実施例１）
表１に示す組成を有する焼鈍・酸洗済みの熱延鋼板（板厚：2.0mm）に、３回の冷間圧延を施して、板厚：0.1mmの冷延鋼板とした。なお、最終の冷間圧延後、表２に示す熱処理（軟化及び合金元素の固溶化目的の熱処理）を施した。なお、最終以外の冷間圧延の後に、それぞれ表２に示す熱処理（軟化及び合金元素の固溶化目的の熱処理）を施した。一部の鋼板では、最終の冷間圧延後には熱処理を施さず、最終以外の冷間圧延の後に表２に示す熱処理（軟化及び合金元素の固溶化目的の熱処理）を施した。
(Example 1)
An annealed and pickled hot-rolled steel sheet (plate thickness: 2.0 mm) having the composition shown in Table 1 was cold-rolled three times to obtain a cold-rolled steel sheet having a plate thickness of 0.1 mm. After the final cold rolling, the heat treatment shown in Table 2 (heat treatment for softening and solidification of alloying elements) was performed. After the cold rolling other than the final one, the heat treatments shown in Table 2 (heat treatment for softening and solidification of alloying elements) were performed respectively. Some steel sheets were not heat-treated after the final cold rolling, but were subjected to the heat treatment shown in Table 2 (heat treatment for softening and solidification of alloying elements) after the non-final cold rolling.
そして、得られた冷延鋼板にさらに、希硝酸電解処理を施したのち、各鋼板表面の孔食発生電位Ｖｃを測定した。孔食発生電位の測定は、研磨なしで、JIS G 0577の規定に準拠して行った。なお、孔食発生電位の測定に際して、試験溶液の塩化ナトリウム水溶液の脱気は実施しなかった。また、照合電極はAg/AgCl電極とした。また、一部の鋼板については希硝酸電解処理は実施しなかった。希硝酸電解処理の条件は、硝酸濃度：3％の希硝酸水溶液（液温：60℃）中で、電流密度：±30mA/cm2で、陽極・陰極電解を合計で20ｓ間、とした。電解は間接電解で、鋼板側がアノード、カソードになるような順番で行った。また、希硝酸電解処理後の鋼板について、ISO 25178の規定に準拠して、算術平均高さSaを測定した。 Then, the obtained cold-rolled steel sheet was further subjected to dilute nitric acid electrolysis treatment, and then the pitting corrosion generation potential Vc on the surface of each steel sheet was measured. The pitting corrosion potential was measured in accordance with JIS G 0577 without polishing. When measuring the pitting corrosion potential, the test solution was not degassed with an aqueous sodium chloride solution. The reference electrode was an Ag / AgCl electrode. In addition, dilute nitric acid electrolysis treatment was not performed on some steel sheets. The conditions for the dilute nitric acid electrolysis treatment were a dilute nitric acid concentration of 3% (liquid temperature: 60 ° C.), a current density of ± 30 mA / cm 2 , and anode / cathode electrolysis for a total of 20 seconds. The electrolysis was indirect electrolysis, and the electrolysis was performed in the order of the anode and the cathode on the steel plate side. In addition, the arithmetic mean height Sa was measured for the steel sheet after the dilute nitric acid electrolysis treatment in accordance with the regulations of ISO 25178.
得られた結果を表２に示す。 The results obtained are shown in Table 2.
本発明例はいずれも、孔食発生電位Ｖｃが（１）式を満足し、高い孔食発生電位を有するステンレス鋼板となっており、優れた耐孔食性を有することが推察される。一方、本発明を外れる比較例は、孔食発生電位Ｖｃが（１）式を満足せず、耐孔食性が低いことが推察される。なお、鋼板No.A6、A7と鋼板No.A8、A9は孔食指数Ｘが同じであるが、孔食発生電位Vcは、C含有量の高い鋼板No.A8、A9のほうが高い値を示している。また、組成が本発明範囲を低く外れる鋼板No.A15、No.A16（比較例）は、孔食発生電位Vcが0以下であり、耐孔食性が低く、耐食性が要求される使途に供することができない。なお、鋼板の面粗さSaは、いずれの鋼板も0.80μm以下であったため、表２には記載しなかった。
（実施例２）
表１に示す鋼No.Ｄの組成を有する熱延鋼板（板厚：2.0mm）に、表３に示す条件の３回の冷間圧延を施して、冷延鋼板（板厚：0.1mm）とした。１回目と２回目の冷間圧延の間に、完全焼鈍を目的とした熱処理（1050℃×5min）を施した。そして、２回目と３回目の冷間圧延の間及び最終の冷間圧延後に、合金元素の固溶化を目的とした熱処理（800℃×5min）を施し、さらに表３に示す条件で希硝酸電解処理を施した。
In each of the examples of the present invention, the pitting corrosion potential Vc satisfies the equation (1), and the stainless steel sheet has a high pitting corrosion potential, and it is presumed that the stainless steel sheet has excellent pitting corrosion resistance. On the other hand, in the comparative example outside the present invention, it is presumed that the pitting corrosion generation potential Vc does not satisfy the equation (1) and the pitting corrosion resistance is low. The pitting corrosion index X is the same for the steel plates No. A6 and A7 and the steel plates No. A8 and A9, but the pitting corrosion potential Vc is higher for the steel plates No. A8 and A9 having a higher C content. ing. Further, the steel sheets No. A15 and No. A16 (comparative examples) whose composition is low outside the scope of the present invention have a pitting corrosion potential Vc of 0 or less, have low pitting corrosion resistance, and are used for applications requiring corrosion resistance. I can't. The surface roughness Sa of the steel sheets was not shown in Table 2 because all the steel sheets had a surface roughness Sa of 0.80 μm or less.
(Example 2)
A hot-rolled steel sheet (plate thickness: 2.0 mm) having the composition of steel No. D shown in Table 1 is cold-rolled three times under the conditions shown in Table 3 to obtain a cold-rolled steel sheet (plate thickness: 0.1 mm). And said. Between the first and second cold rolling, a heat treatment (1050 ° C. × 5 min) was performed for the purpose of complete annealing. Then, during the second and third cold rollings and after the final cold rolling, heat treatment (800 ° C. × 5 min) was performed for the purpose of solidifying the alloying elements, and dilute nitric acid electrolysis was performed under the conditions shown in Table 3. Processed.
そして、実施例１と同様に、各鋼板表面の孔食発生電位Ｖｃを測定した。また、実施例１と同様に、各鋼板について、ISO 25178の規定に準拠して、算術平均高さSaを測定した。 Then, the pitting corrosion potential Vc on the surface of each steel sheet was measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the arithmetic mean height Sa was measured for each steel sheet in accordance with the provisions of ISO 25178.
得られた結果を表３に示す。 The results obtained are shown in Table 3.
本発明例はいずれも、孔食発生電位Ｖｃが（１）式を満足し、高い孔食発生電位を有するステンレス鋼板となっており、優れた耐孔食性を有することが推察される。一方、本発明を外れる比較例は、孔食発生電位Ｖｃが（１）式を満足せず、耐孔食性が低いことが推察される。また、本発明例はいずれも、算術平均高さSaが0.80μm以下と優れた表面性状を呈している。一方、希硝酸電解処理条件が本発明範囲を低く外れる比較例は、孔食発生電位Ｖｃが（１）式を満足せず、耐孔食性が低いことが推察される。一方、希硝酸電解処理条件が本発明範囲を高く外れる比較例では、孔食発生電位Ｖｃは（１）式を満たすが、算術平均高さSaが0.80μmを超えて荒れた表面となり、面粗さの評価は「×」となっている。 In each of the examples of the present invention, the pitting corrosion potential Vc satisfies the equation (1), and the stainless steel sheet has a high pitting corrosion potential, and it is presumed that the stainless steel sheet has excellent pitting corrosion resistance. On the other hand, in the comparative example outside the present invention, it is presumed that the pitting corrosion generation potential Vc does not satisfy the equation (1) and the pitting corrosion resistance is low. In addition, all of the examples of the present invention exhibit excellent surface properties with an arithmetic mean height Sa of 0.80 μm or less. On the other hand, in the comparative example in which the dilute nitric acid electrolysis treatment conditions are low outside the range of the present invention, it is presumed that the pitting corrosion potential Vc does not satisfy the equation (1) and the pitting corrosion resistance is low. On the other hand, in the comparative example in which the dilute nitrate electrolysis treatment conditions are far outside the scope of the present invention, the pitting corrosion potential Vc satisfies the equation (1), but the arithmetic mean height Sa exceeds 0.80 μm and the surface becomes rough and the surface is rough. The evaluation of the pitting corrosion is "x".
Claims (5)
C：0.40％以下、 Si：1.00％以下、
Mn：2.00％以下、 P：0.045％以下、
S：0.030％以下、 Ni：3.5～20.0％、
Cr：15.00～30.00％、 Mo：0～3.5％、
N：0.30％以下
を含有し、かつCr、Moを下記（２）式で定義されるＸが15.0～40.0を満足するように含み、残部Feおよび不可避的不純物からなる組成を有し、かつJIS G 0577の規定に準拠して測定した表面の孔食発生電位Ｖｃが、下記（１）式を満足することを特徴とするオーステナイト系ステンレス鋼板。
記
Ｖｃ ＞ －0.006Ｘ3－0.35Ｘ2＋63Ｘ－646 ……（１）
ここで、 Ｘ＝Cr＋3.3Mo ……（２）
Cr、Mo：各元素の含有量（質量％） By mass%,
C: 0.40% or less, Si: 1.00% or less,
Mn: 2.00% or less, P: 0.045% or less,
S: 0.030% or less, Ni: 3.5-20.0%,
Cr: 15.00 to 30.00%, Mo: 0 to 3.5%,
N: Contains 0.30% or less, contains Cr and Mo so that X defined by the following equation (2) satisfies 15.0 to 40.0, has a composition consisting of the balance Fe and unavoidable impurities, and JIS. An austenitic stainless steel plate characterized in that the pitting corrosion potential Vc on the surface measured in accordance with the provisions of G 0577 satisfies the following equation (1).
Note Vc> -0.006X 3 -0.35X 2 + 63X-646 …… (1)
Here, X = Cr + 3.3Mo …… (2)
Cr, Mo: Content of each element (mass%)
前記冷間圧延のうちの最終の冷間圧延の後に、あるいは前記冷間圧延のうちの最終以外の冷間圧延の後に、700℃超え950℃以下の範囲の温度で20ｓ～10min保持する熱処理を施し、最終に、希硝酸電解処理を施すことを特徴とするオーステナイト系ステンレス鋼板の製造方法。 In manufacturing a cold-rolled steel sheet by subjecting a hot-rolled steel sheet having the composition according to claim 1 or 2 to cold rolling once or a plurality of times.
After the final cold rolling of the cold rolling, or after the non-final cold rolling of the cold rolling, heat treatment is performed to maintain the temperature in the range of 700 ° C. and 950 ° C. for 20 s to 10 min. A method for producing an austenitic stainless steel sheet, which comprises applying and finally subjecting a dilute nitric acid electrolytic treatment.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115821153A (en) * | 2022-06-27 | 2023-03-21 | 浙江吉森金属科技有限公司 | Stainless steel for temperature sensor shell and manufacturing method thereof |
| CN118086791A (en) * | 2023-12-26 | 2024-05-28 | 北京理工大学重庆创新中心 | High-temperature oxidation resistant hot forming steel and preparation method and application thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5647551A (en) * | 1979-09-28 | 1981-04-30 | Nippon Kinzoku Kogyo Kk | Reduced molybdenum-type austenite stainless steel having resistance to sea water |
| JPS5877555A (en) * | 1981-11-04 | 1983-05-10 | Nippon Yakin Kogyo Co Ltd | Austenitic stainless steel with superior pitting corrosion resistance and weather resistance |
| JPH01162786A (en) * | 1987-12-21 | 1989-06-27 | Kawasaki Steel Corp | Method for pickling high strength austenitic stainless steel |
| JP2005023396A (en) * | 2003-07-04 | 2005-01-27 | Sumitomo Metal Ind Ltd | Austenitic stainless steel sheet and its production method |
| WO2007138815A1 (en) * | 2006-05-30 | 2007-12-06 | Sumitomo Metal Industries, Ltd. | Austenitic stainless steel |
| JP2008274386A (en) * | 2007-05-07 | 2008-11-13 | Aichi Steel Works Ltd | Surface-treated stainless steel excellent in design characteristics and corrosion resistance and method for producing the same |
| WO2009150885A1 (en) * | 2008-06-09 | 2009-12-17 | 東京ステンレス研磨興業株式会社 | Stainless steel and surface treatment method for stainless steel |
-
2020
- 2020-09-01 JP JP2020146612A patent/JP7210516B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5647551A (en) * | 1979-09-28 | 1981-04-30 | Nippon Kinzoku Kogyo Kk | Reduced molybdenum-type austenite stainless steel having resistance to sea water |
| JPS5877555A (en) * | 1981-11-04 | 1983-05-10 | Nippon Yakin Kogyo Co Ltd | Austenitic stainless steel with superior pitting corrosion resistance and weather resistance |
| JPH01162786A (en) * | 1987-12-21 | 1989-06-27 | Kawasaki Steel Corp | Method for pickling high strength austenitic stainless steel |
| JP2005023396A (en) * | 2003-07-04 | 2005-01-27 | Sumitomo Metal Ind Ltd | Austenitic stainless steel sheet and its production method |
| WO2007138815A1 (en) * | 2006-05-30 | 2007-12-06 | Sumitomo Metal Industries, Ltd. | Austenitic stainless steel |
| JP2008274386A (en) * | 2007-05-07 | 2008-11-13 | Aichi Steel Works Ltd | Surface-treated stainless steel excellent in design characteristics and corrosion resistance and method for producing the same |
| WO2009150885A1 (en) * | 2008-06-09 | 2009-12-17 | 東京ステンレス研磨興業株式会社 | Stainless steel and surface treatment method for stainless steel |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115821153A (en) * | 2022-06-27 | 2023-03-21 | 浙江吉森金属科技有限公司 | Stainless steel for temperature sensor shell and manufacturing method thereof |
| CN118086791A (en) * | 2023-12-26 | 2024-05-28 | 北京理工大学重庆创新中心 | High-temperature oxidation resistant hot forming steel and preparation method and application thereof |
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