JP5272078B2 - Austenitic stainless steel with high strength and high corrosion resistance added with carbon and nitrogen composite and method for producing the same - Google Patents
Austenitic stainless steel with high strength and high corrosion resistance added with carbon and nitrogen composite and method for producing the same Download PDFInfo
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Description
本発明は、高強度・高耐食の炭窒素複合添加オーステナイト系ステンレス鋼及びその製造方法に関するものである。 The present invention relates to a high-strength, high-corrosion-resistant carbon-nitrogen composite-added austenitic stainless steel and a method for producing the same.
一般的にオーステナイト系ステンレス鋼は、多様な加工熱処理工程を用いた相変態及び加工熱処理を通じて優れた強度と柔軟性の組み合わせを具現している炭素鋼とは異なり、熱処理による特性向上を期待しにくいため、鋼の諸般特性の向上を主に合金元素の添加に依存している。 In general, austenitic stainless steels are unlikely to have improved properties due to heat treatment, unlike carbon steels that have realized a combination of excellent strength and flexibility through phase transformations and thermomechanical processes using various thermomechanical processes. Therefore, improvement of various properties of steel mainly depends on the addition of alloying elements.
したがって、強度、柔軟性、耐食性など優れた特性を確保すること以外に、高価な合金元素の添加を最小限に抑えたり他の元素で置換したりすることにより製造原価の面で優位を占めることが合金開発において重要な技術的課題である。 Therefore, in addition to ensuring excellent properties such as strength, flexibility, and corrosion resistance, it has an advantage in terms of manufacturing cost by minimizing the addition of expensive alloy elements or replacing with other elements Is an important technical issue in alloy development.
既存の研究または発明で報告されたオーステナイト系ステンレス鋼の大部分は、重量％で１６〜２０％のクロム（Ｃｒ）、６〜１２％のニッケル（Ｎｉ）、０〜２％のモリブデン（Ｍｏ）及び０．０３〜０．１５％の炭素（Ｃ）を含み、引張強度が５００〜６００ＭＰａで延伸率が４０％のレベルの機械的特性を有する。 Most of the austenitic stainless steels reported in existing studies or inventions are 16-20% chromium (Cr), 6-12% nickel (Ni), 0-2% molybdenum (Mo) by weight. And 0.03 to 0.15% carbon (C), and has mechanical properties of a tensile strength of 500 to 600 MPa and a stretch rate of 40%.
前記合金元素のうちニッケル（Ｎｉ）は、効率的なオーステナイト安定化元素であり、加工性向上に寄与する長所もあって、需給量全体の６５％以上のオーステナイト系ステンレス鋼において合金元素として使用されている。 Among the alloy elements, nickel (Ni) is an efficient austenite stabilizing element, and has an advantage of improving workability, and is used as an alloy element in austenitic stainless steels of 65% or more of the total supply and demand. ing.
しかし、ニッケル（Ｎｉ）の価格が２００１年から６年間に７００％以上上昇し、特に２００７年の１年間には２倍以上に暴騰して、ニッケル価格がステンレス鋼の原価を定める主要指標として作用している。このような経済的側面以外にも、人体アレルギーを誘発することやリサイクル時に有害ガスを排出することなど、人体及び環境親和性に逆行する問題点が提起されている。 However, the price of nickel (Ni) has risen more than 700% in 6 years since 2001, and more than doubled in the year of 2007, and nickel price acts as a key indicator for determining the cost of stainless steel. doing. In addition to such economic aspects, problems have been raised against human and environmental compatibility, such as inducing human allergies and exhausting harmful gases during recycling.
そのため、ニッケル（Ｎｉ）含量が高い既存のステンレス鋼が有する多くの問題点を解決するために最近開発された新しいステンレス鋼として、ＳＴＳ２００系合金として知られたＦｅ−Ｃｒ−Ｍｎ系合金と、合金元素としての窒素が有する長所を積極活用して諸般特性を向上させた高窒素ステンレス鋼がある。 Therefore, as a new stainless steel recently developed to solve many problems of existing stainless steel having a high nickel (Ni) content, an Fe—Cr—Mn alloy known as an STS200 alloy, and an alloy There are high nitrogen stainless steels that have improved various characteristics by actively utilizing the advantages of nitrogen as an element.
窒素は強力なオーステナイト安定化元素であり、固溶強化効果が大きく、強度増加に随伴した柔軟性の減少が少なく、孔食抵抗性を含む耐食性の向上などの多くの長所がある。従来は、鉄鋼材料内に窒素を安定的に確保するための製造工程上の難しさのために高窒素鋼の開発を活発に進めることができなかったが、最近、窒素雰囲気下での加圧誘導溶解、ＰＥＳＲ(pressurized electroslag remelting)、粉末冶金法、固相窒化法などの多様な製造工程技術の発展によって多くの研究開発が進行されている。 Nitrogen is a strong austenite stabilizing element, has a large solid solution strengthening effect, has a small decrease in flexibility accompanying an increase in strength, and has many advantages such as improved corrosion resistance including pitting resistance. Previously, the development of high nitrogen steels could not be actively promoted due to difficulties in the manufacturing process to stably secure nitrogen in steel materials. Much research and development has been progressed by the development of various manufacturing process technologies such as induction melting, PESR (pressurized electroslag remelting), powder metallurgy, and solid phase nitriding.
しかし、高窒素鋼の汎用化において最も大きな障害要因は、高価な設備と複雑な製造工程が求められる加圧誘導溶解またはＰＥＳＲのような特殊な製造工程を経なければならないという点である。 However, the biggest obstacle to the generalization of high nitrogen steel is that it requires a special manufacturing process such as pressure induction melting or PESR, which requires expensive equipment and a complicated manufacturing process.
加圧の工程は、液状状態で高い窒素含量を確保することと同時に、凝固時に窒素固溶度を急激に減少させるδフェライト区間を最小化することができるという長所があり、大型の高窒素鋼鋳塊の製造には必要であるが、既存のステンレス鋼製造に用いられる製造工程設備を改造したり新しい設備を導入したりすることが不可避であるため、商業化には多くの問題点がある。 The pressurization process has the advantage of ensuring a high nitrogen content in the liquid state and at the same time minimizing the δ ferrite section that sharply reduces the nitrogen solid solubility during solidification, and is a large high nitrogen steel Necessary for the production of ingots, but there are many problems in commercialization because it is inevitable to modify the production process equipment used to manufacture existing stainless steel or introduce new equipment. .
このような問題点を解決するために、最近、ベルンス（Ｈ．Ｂｅｒｎｓ）らのグループは、ＰＣＴ／ＥＰ２００５／００８９６０（国際公開第２００６／０２７０９１号、特許文献１）において、ニッケル（Ｎｉ）の使用を最小限に抑え、クロム（Ｃｒ）を１６〜２１重量％、マンガン（Ｍｎ）を１６〜２１重量％、モリブデン（Ｍｏ）を０．５〜２重量％、炭素（Ｃ）及び窒素（Ｎ）を合計で０．８重量％以上を含むオーステナイト系ステンレス鋼を発表した。しかし、ベルンスらのグループの特許出願では、マンガン（Ｍｎ）の割合が高くて耐食性が低いという問題がある。 In order to solve such problems, a group of H. Berns et al. Recently used the use of nickel (Ni) in PCT / EP2005 / 008960 (International Publication No. 2006/027091). , Chromium (Cr) 16-21% by weight, manganese (Mn) 16-21% by weight, molybdenum (Mo) 0.5-2% by weight, carbon (C) and nitrogen (N) An austenitic stainless steel containing 0.8% by weight or more in total. However, the patent application of the Berns et al group has a problem that the ratio of manganese (Mn) is high and the corrosion resistance is low.
そこで、本発明者らは、侵入型元素である炭素と窒素を複合添加して、侵入型元素（Ｃ＋Ｎ、Ｃ／Ｎ）と置換型元素（Ｍｎ＋Ｃｒ、Ｍｎ／Ｃｒ、または０．５Ｗ＋Ｍｏ）の含量を制御することを通じて、高価で環境及び人体に有害な合金元素であるＮｉ含量を最小限に抑え、加圧溶解法ではなく常圧溶解法によって経済性に優れた高強度・高耐食性を有するオーステナイト系ステンレス鋼を開発して本発明を完成した。 Therefore, the present inventors combined the interstitial elements carbon and nitrogen, and the contents of the interstitial elements (C + N, C / N) and substitutional elements (Mn + Cr, Mn / Cr, or 0.5W + Mo). Austenite which has high strength and high corrosion resistance with excellent economic efficiency by controlling atmospheric pressure instead of pressurized melting method, minimizing Ni content, which is expensive and harmful to the environment and human body Stainless steel was developed to complete the present invention.
本発明の目的は、前記のような問題点を解決するためのもので、侵入型元素（Ｃ＋Ｎ、Ｃ／Ｎ）と置換型元素（Ｍｎ＋Ｃｒ、Ｍｎ／Ｃｒ、または０．５Ｗ＋Ｍｏ）の含量を制御することを通じて、耐食性を向上させた炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナ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 solve the above-described problems, and controls the contents of interstitial elements (C + N, C / N) and substitutional elements (Mn + Cr, Mn / Cr, or 0.5W + Mo). Thus, an object of the present invention is to provide an austenitic stainless steel having high strength and high corrosion resistance in which carbon (C) and nitrogen (N) with improved corrosion resistance are added in combination.
本発明の他の目的は、前記オーステナイト系ステンレス鋼の製造方法を提供することにある。 Another object of the present invention is to provide a method for producing the austenitic stainless steel.
前記目的を達成するために、本発明は、侵入型元素である炭素（Ｃ）と窒素（Ｎ）を複合添加することによって、高価で環境及び人体に有害な合金元素であるニッケル（Ｎｉ）含量を最小限に抑え、加圧溶解法ではなく常圧溶解法で製造が可能で経済性に優れたオーステナイト系ステンレス鋼及びその製造方法を提供する。 In order to achieve the above object, the present invention provides a nickel (Ni) content which is an expensive and harmful element to the environment and the human body by adding carbon (C) and nitrogen (N) which are interstitial elements. An austenitic stainless steel that can be manufactured not by a pressure melting method but by an atmospheric pressure melting method and is excellent in economic efficiency, and a method for manufacturing the same.
本発明による製造方法は、安価な製造原価で合金の製造を可能にするので、開発鋼種の価格競争力を高めることができる。また、本発明によって製造されたオーステナイト系ステンレス鋼は、侵入型元素（Ｃ＋Ｎ、Ｃ／Ｎ）と置換型元素（Ｍｎ＋Ｃｒ、Ｍｎ／Ｃｒ、または０．５Ｗ＋Ｍｏ）の含量を制御することを通じて、８５０ＭＰａ以上の引張強度及び４５％以上の均一延伸率を有し、成形加工性が向上するのみならず優れた耐食性を示し、人体に有害な合金元素であるニッケル（Ｎｉ）含量を最小限に抑えることによって生体適合性が向上するので、既存のオーステナイトステンレス鋼の適用分野及び高強度・高耐食性が求められる海洋構造物、淡水化設備、オイル及びガス設備／採掘用素材、運送機関用素材などに適用が可能であるばかりか、医療用生体材料、時計などの装身具を含む多様な機能性部品の製造にも有用である。 Since the production method according to the present invention enables the production of an alloy at a low production cost, the price competitiveness of the developed steel type can be enhanced. In addition, the austenitic stainless steel produced according to the present invention is 850 MPa or more by controlling the contents of interstitial elements (C + N, C / N) and substitutional elements (Mn + Cr, Mn / Cr, or 0.5W + Mo). It has a tensile strength of 45% and a uniform stretch ratio of 45% or more, exhibits not only improved moldability but also excellent corrosion resistance, and minimizes the content of nickel (Ni), an alloy element harmful to the human body. Because biocompatibility is improved, it can be applied to existing austenitic stainless steel applications, marine structures that require high strength and high corrosion resistance, desalination facilities, oil and gas facilities / mining materials, transportation engine materials, etc. Not only is it possible, but it is also useful for the production of various functional parts including accessories such as medical biomaterials and watches.
以下、本発明を詳しく説明する。
本発明の炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナイト系ステンレス鋼は、８〜１２重量％のマンガン（Ｍｎ）と、１５〜２０重量％のクロム（Ｃｒ）と、２重量％以下のニッケル（Ｎｉ）と、４重量％以下のタングステン（Ｗ）と、２重量％以下のモリブデンと、合計（Ｃ＋Ｎ）で０．６〜１．０重量％の炭素（Ｃ）と窒素（Ｎ）と、残部である鉄（Ｆｅ）及びその他の不可避な不純物とを含んで構成されることを特徴とする。
The present invention will be described in detail below.
The austenitic stainless steel having high strength and high corrosion resistance to which carbon (C) and nitrogen (N) of the present invention are added is composed of 8 to 12 wt% manganese (Mn) and 15 to 20 wt% chromium ( Cr), 2 wt% or less nickel (Ni), 4 wt% or less tungsten (W), 2 wt% or less molybdenum, and a total (C + N) of 0.6 to 1.0 wt% carbon. It is characterized by comprising (C), nitrogen (N), and the balance iron (Fe) and other inevitable impurities.
前記クロム（Ｃｒ）に対する前記マンガン（Ｍｎ）の割合（Ｍｎ／Ｃｒ）は、０．５以上１．０以下であることを特徴とする。
前記マンガンは、ベルンスらのグループＰＣＴ／ＥＰ２００５／００８９６０）が以前に発表したステンレス鋼に含まれるマンガンの含量（１６〜２１重量％）より少なく、本発明によるステンレス鋼の孔食抵抗性を向上させることができる。
The ratio of manganese (Mn) to chromium (Cr) (Mn / Cr) is 0.5 or more and 1.0 or less.
The manganese is less than the manganese content (16-21% by weight) contained in stainless steel previously announced by Berns et al. Group PCT / EP2005 / 008960) and improves the pitting resistance of the stainless steel according to the present invention. be able to.
前記マンガン（Ｍｎ）と前記クロム（Ｃｒ）の合計の含量（Ｍｎ＋Ｃｒ）は、３０重量％以下であることを特徴とする。
前記窒素（Ｎ）の含量は、０．３重量％以上であることを特徴とする。
The total content of manganese (Mn) and chromium (Cr) (Mn + Cr) is 30% by weight or less.
The nitrogen (N) content is 0.3% by weight or more.
前記タングステン（Ｗ）と前記モリブデン（Ｍｏ）の含量は、０．５Ｗ＋Ｍｏが３重量％以下であることを特徴とする。０．５Ｗ＋Ｍｏが３重量％を超えると、製造原価が上昇し、また残存するδフェライト分率を増加させて有害な第２相を形成する問題がある。 The tungsten (W) and the molybdenum (Mo) content is characterized in that 0.5 W + Mo is 3 wt% or less. If 0.5 W + Mo exceeds 3% by weight, the production cost increases, and the remaining δ ferrite fraction is increased to form a harmful second phase.
以下に本発明によるオーステナイト系ステンレス鋼内の合金元素について詳しく説明する。
ニッケル（Ｎｉ）は、オーステナイト安定化能は大きいが、前述したように高価で環境及び人体に有害な元素であるので、添加量を最小限に抑えた。しかし、オーステナイト系ステンレス鋼にニッケル（Ｎｉ）を少量添加した場合、熱間及び冷間加工性が向上し、また液状からの凝固時にδフェライトの形成を抑制させる能力を有するようになるので、ニッケル（Ｎｉ）の添加量は２重量％以下に設定した。
The alloy elements in the austenitic stainless steel according to the present invention will be described in detail below.
Nickel (Ni) has a large austenite stabilizing ability, but is expensive and harmful to the environment and the human body as described above, so the amount added was minimized. However, when a small amount of nickel (Ni) is added to the austenitic stainless steel, the hot and cold workability is improved, and the ability to suppress the formation of δ ferrite during solidification from a liquid will be improved. The amount of (Ni) added was set to 2% by weight or less.
クロム（Ｃｒ）は、ステンレス鋼に要求される耐食性確保のために必須な合金元素であり、大抵のオーステナイトステンレス鋼に１５重量％以上添加される。しかし、クロム（Ｃｒ）を過剰に添加した場合、凝固後に過多のδフェライトが残存したり、熱処理時に多くの種類の有害な第２析出相の生成が促進されたりしてステンレス鋼の耐食性及び加工性が低下する。したがって、前記ステンレス鋼では、クロム（Ｃｒ）の含量を１５〜２０重量％の範囲に制限した。 Chromium (Cr) is an alloy element essential for ensuring the corrosion resistance required for stainless steel, and is added to most austenitic stainless steels by 15% by weight or more. However, when chromium (Cr) is added excessively, excessive δ ferrite remains after solidification or the formation of many kinds of harmful second precipitation phases during heat treatment is promoted, resulting in corrosion resistance and processing of stainless steel. Sex is reduced. Therefore, in the stainless steel, the chromium (Cr) content is limited to a range of 15 to 20% by weight.
マンガン（Ｍｎ）は、高価なニッケル（Ｎｉ）の代替となることができるオーステナイト安定化元素であり、ステンレス鋼に添加することにより窒素固溶度を増加させ、材料の強度を増加させる役割をする。しかし、マンガン（Ｍｎ）を過剰に添加した場合、不純物元素である硫黄（Ｓ）や酸素（Ｏ）と結合してマンガン硫化物（ＭｎＳ）やマンガン酸化物（ＭｎＯ）などの非金属介在物を形成する。こうして生成する非金属介在物が孔食の主な発生場所として作用してオーステナイト系ステンレス鋼の孔食抵抗性を低下させるため、マンガンの含量は８〜１２重量％の範囲に制限した。 Manganese (Mn) is an austenite stabilizing element that can replace expensive nickel (Ni), and when added to stainless steel, it increases nitrogen solid solubility and plays a role in increasing the strength of the material. . However, when manganese (Mn) is excessively added, non-metallic inclusions such as manganese sulfide (MnS) and manganese oxide (MnO) are combined with the impurity elements sulfur (S) and oxygen (O). Form. Since the non-metallic inclusions thus produced act as a main occurrence site of pitting corrosion and reduce the pitting corrosion resistance of the austenitic stainless steel, the manganese content is limited to the range of 8 to 12% by weight.
モリブデン（Ｍｏ）は、クロム（Ｃｒ）とともにオーステナイト系ステンレス鋼の耐食性を向上させる合金元素である。しかし、過剰に添加した場合、凝固後に残存するδフェライト分率が増加し、クロム（Ｃｒ）と同様に炭化物、金属間化合物などの有害な第２相を形成して製造原価の上昇の要因になるので、モリブデンの含量は２重量％以下に制限した。 Molybdenum (Mo) is an alloy element that improves the corrosion resistance of austenitic stainless steel together with chromium (Cr). However, if added excessively, the fraction of δ ferrite remaining after solidification will increase, forming a harmful second phase such as carbides and intermetallic compounds as well as chromium (Cr), which will increase the manufacturing cost. Therefore, the molybdenum content was limited to 2% by weight or less.
タングステン（Ｗ）は、クロム（Ｃｒ）及びモリブデン（Ｍｏ）とともにステンレス鋼の耐食性を向上させる合金元素であり、タングステン（Ｗ）は、ステンレス鋼でモリブデン（Ｍｏ）の１／２当量にあたるフェライト安定化能と孔食抵抗性向上能を有するので、モリブデン（Ｍｏ）の効果的な代替となることができる元素である。合金元素としてのタングステン（Ｗ）は、ステンレス鋼の高温強度を増加させてクリープ抵抗性を向上させる。また、非酸化性雰囲気での耐食性を一般に増加させて金属の不動態化を促進し、合金の孔食抵抗性を向上させる効果がある。タングステンもフェライト安定化元素であるので過剰に添加した場合には、δフェライト分率が増加し、製造原価の上昇の要因になるので、タングステンの含量は４重量％以下に制限した。また、優れた耐食性と経済的な製造原価の確保のために、０．５Ｗ＋Ｍｏ含量を３重量％以下に制限した。 Tungsten (W) is an alloying element that improves the corrosion resistance of stainless steel together with chromium (Cr) and molybdenum (Mo). Tungsten (W) is a ferritic stabilizer equivalent to 1/2 equivalent of molybdenum (Mo) in stainless steel. Is an element that can effectively replace molybdenum (Mo). Tungsten (W) as an alloy element increases the high temperature strength of stainless steel and improves creep resistance. In addition, it has the effect of generally increasing the corrosion resistance in a non-oxidizing atmosphere to promote metal passivation and improving the pitting resistance of the alloy. Tungsten is also a ferrite stabilizing element, so when added in excess, the δ ferrite fraction increases and causes an increase in manufacturing cost. Therefore, the tungsten content is limited to 4% by weight or less. In order to secure excellent corrosion resistance and economical production costs, the 0.5 W + Mo content was limited to 3% by weight or less.
窒素（Ｎ）は、炭素（Ｃ）及びマンガン（Ｍｎ）とともにオーステナイト安定化元素として、上述の問題点を有するニッケル（Ｎｉ）の代替の目的で添加され、また柔軟性が大きく低下することなく強度を増加させて孔食抵抗性を含む耐食性を向上させるための元素である。このような効果のために窒素は、０．３重量％以上使用しなければならない。しかし、窒素（Ｎ）は、過剰に添加した場合、柔軟性を減少させるだけでなく脆性を招く問題点がある。 Nitrogen (N) is added as an austenite stabilizing element together with carbon (C) and manganese (Mn) for the purpose of substituting nickel (Ni) having the above-mentioned problems, and the strength is not greatly reduced. It is an element for increasing corrosion resistance and improving corrosion resistance including pitting resistance. For such an effect, nitrogen must be used in an amount of 0.3% by weight or more. However, when nitrogen (N) is added excessively, there is a problem that not only the flexibility is reduced but also brittleness is caused.
炭素（Ｃ）は、窒素（Ｎ）と同様にオーステナイト安定化を目的に添加され、固溶強化効果を通じてステンレス鋼の強度を向上させる役割をする。ただし、炭素（Ｃ）を過剰に添加した場合、機械的特性（代表的には靭性）が低下し、またＭ２３Ｃ６、Ｍ６Ｃなどの炭化物が臨界生成してオーステナイト系ステンレス鋼の鋭敏化（sensitization）が促進され、結果的に耐食性が低下する。 Carbon (C) is added for the purpose of stabilizing austenite like nitrogen (N), and plays a role of improving the strength of stainless steel through a solid solution strengthening effect. However, when carbon (C) is excessively added, mechanical properties (typically toughness) are lowered, and carbides such as M 23 C 6 and M 6 C are critically formed, and the austenitic stainless steel is sensitive. Sensitization is promoted, resulting in a decrease in corrosion resistance.
したがって、本発明のステンレス鋼では、炭素（Ｃ）と窒素（Ｎ）の合計の含量（Ｃ＋Ｎ）を０．６〜１．０重量％の範囲に制限した。
一方、図１は、炭素（Ｃ）を添加していない３種類のＦｅ−Ｃｒ−Ｍｎ系（Ｆｅ−１８Ｃｒ−１０Ｍｎ、Ｆｅ−１５Ｃｒ−１５Ｍｎ、Ｆｅ−１３Ｃｒ−２０Ｍｎ）合金と、炭素（Ｃ）を０．４重量％添加した３種類のＦｅ−Ｃｒ−Ｍｎ−０．４Ｃ系合金の、窒素分圧１気圧での窒素固溶度を計算した結果である。図示したように、炭素（Ｃ）の添加によって液状での窒素固溶度は、０．３８重量％から０．３重量％に減少するが、凝固時のδフェライト形成による窒素固溶度の減少が著しく減るため、凝固時に発生し得る窒素損失を減らすことができるという効果をその代わりに得ることができる。これは、炭素（Ｃ）の添加によって高温領域でのオーステナイト相の安定性が増加してフェライト領域が縮小するために現れる現象で、常圧（窒素分圧１気圧）状態で炭素（Ｃ）と窒素（Ｎ）を複合添加した場合に、目標とする窒素固溶度を容易に確保することができることを示している。
Therefore, in the stainless steel of the present invention, the total content (C + N) of carbon (C) and nitrogen (N) is limited to a range of 0.6 to 1.0% by weight.
On the other hand, FIG. 1 shows three types of Fe—Cr—Mn (Fe-18Cr-10Mn, Fe-15Cr-15Mn, Fe-13Cr-20Mn) alloys not added with carbon (C) and carbon (C). Is a result of calculating the nitrogen solid solubility at a partial pressure of nitrogen of three types of Fe-Cr-Mn-0.4C based alloys to which 0.4 wt% is added. As shown in the figure, the addition of carbon (C) reduces the nitrogen solid solubility in the liquid state from 0.38 wt% to 0.3 wt%, but the decrease in nitrogen solid solubility due to the formation of δ ferrite during solidification. However, the effect of reducing the nitrogen loss that can occur during solidification can be obtained instead. This is a phenomenon that appears because the addition of carbon (C) increases the stability of the austenite phase in the high temperature region and shrinks the ferrite region, and carbon (C) in a normal pressure (nitrogen partial pressure of 1 atm) state. It shows that when nitrogen (N) is added in combination, the target nitrogen solid solubility can be easily secured.
また、炭素（Ｃ）と窒素（Ｎ）の合計の含量（Ｃ＋Ｎ）を０．６〜１．０重量％の範囲に制限した理由は、下記のとおりである。すなわち、窒素（Ｎ）が合金元素として添加されると、オーステナイト基地の自由電子濃度が増加し、これにより金属結合が促進されてオーステナイト基地内部で短範囲規則度が増大する。窒素添加時に発生するこのような原子結合の特殊性のために、合金元素の偏析による有害な第２相の生成が抑制されるのと同時に、柔軟性及び耐食性が向上する。すなわち、窒素（Ｎ）の添加が鋼の諸般特性を向上させることについての物理学的根拠は、自由電子濃度の増加に起因したものであるといえる。類似の侵入型元素の含量で、炭素（Ｃ）の添加は鋼の自由電子濃度に大きな影響を及ぼさない一方、窒素（Ｎ）は一定の含量範囲で自由電子濃度を効果的に増加させる。しかし、炭素（Ｃ）と窒素（Ｎ）を複合添加した場合、二つの元素のシナジー効果により、窒素（Ｎ）を単独で添加した場合と比較して自由電子濃度が顕著に増加し、炭素（Ｃ）と窒素（Ｎ）の合計の含量（Ｃ＋Ｎ）が０．８５重量％で最大値を示した後、再び減少する。したがって、本発明では、前記の物理学的根拠とともに、炭素（Ｃ）と窒素（Ｎ）を過剰に添加した場合に発生する有害な第２析出相の生成を防止するために、合金元素として添加される炭素（Ｃ）と窒素（Ｎ）の合計の含量（Ｃ＋Ｎ）を０．６〜１．０重量％の範囲に制限した。 The reason why the total content (C + N) of carbon (C) and nitrogen (N) is limited to the range of 0.6 to 1.0% by weight is as follows. That is, when nitrogen (N) is added as an alloying element, the free electron concentration of the austenite base increases, thereby promoting metal bonding and increasing the short range order within the austenite base. Due to the peculiarity of such atomic bonds generated when nitrogen is added, the generation of harmful second phase due to segregation of alloy elements is suppressed, and at the same time, flexibility and corrosion resistance are improved. That is, it can be said that the physical basis for the addition of nitrogen (N) to improve various properties of steel is due to the increase in free electron concentration. With similar interstitial element content, the addition of carbon (C) does not significantly affect the free electron concentration of steel, while nitrogen (N) effectively increases the free electron concentration in a certain content range. However, when carbon (C) and nitrogen (N) are added in combination, the free electron concentration significantly increases as compared to the case where nitrogen (N) is added alone due to the synergistic effect of the two elements. The total content (C + N) of C) and nitrogen (N) reaches a maximum at 0.85% by weight and then decreases again. Therefore, in the present invention, in addition to the above physical basis, it is added as an alloy element in order to prevent the formation of harmful second precipitation phases that occur when carbon (C) and nitrogen (N) are excessively added. The combined content of carbon (C) and nitrogen (N) (C + N) was limited to the range of 0.6 to 1.0 wt%.
また、本発明による炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナイト系ステンレス鋼の製造方法は、電解鉄、Ｆｅ−５０％Ｍｎ、Ｆｅ−６０％Ｃｒ、Ｆｅ−５８．８％Ｃｒ−６．６％Ｎ、７５．１％Ｍｎ−１７．４％Ｆｅ−６．８％Ｃ、タングステン及び／またはモリブデンを含む母合金を真空溶解炉に装入する母合金装入工程と、前記母合金が装入された真空溶解炉を真空状態に維持する真空維持工程と、前記真空溶解炉を加熱して母合金を溶融する母合金溶融工程と、前記真空溶解炉の内部に窒素ガスを注入する窒素含量調整工程と、溶融された母合金を撹拌する溶融合金撹拌工程と、前記真空溶解炉の内部で撹拌された溶融合金を出湯して鋳塊を形成する鋳塊形成工程と、形成された鋳塊を熱間圧延する工程と、熱間圧延された合金を水冷処理して機械的特性及び耐食性に有害な炭化物の析出を抑制する工程とを含んで成り立つことを特徴とする。 In addition, the method for producing high strength and high corrosion resistance austenitic stainless steel to which carbon (C) and nitrogen (N) are added in combination according to the present invention includes electrolytic iron, Fe-50% Mn, Fe-60% Cr, A mother in which a mother alloy containing Fe-58.8% Cr-6.6% N, 75.1% Mn-17.4% Fe-6.8% C, tungsten and / or molybdenum is charged into a vacuum melting furnace. An alloy charging step, a vacuum maintaining step for maintaining the vacuum melting furnace charged with the mother alloy in a vacuum state, a mother alloy melting step for melting the mother alloy by heating the vacuum melting furnace, and the vacuum melting A nitrogen content adjusting step for injecting nitrogen gas into the furnace, a molten alloy stirring step for stirring the molten mother alloy, and a molten alloy stirred in the vacuum melting furnace are discharged to form an ingot. Ingot forming process and hot rolling of the formed ingot And that step, the hot rolled alloy, characterized in that the hold and a step of inhibiting the precipitation of deleterious carbides mechanical properties and corrosion resistance and water-cooling process.
前記真空維持工程は、真空溶解炉の内部が１０−３ｔｏｒｒ（≒０．１３Ｐａ）以下の真空度を有するようにする工程であることを特徴とする。
前記窒素含量調整工程は、前記真空溶解炉の内部に窒素ガスを注入する窒素注入工程と、前記真空溶解炉の内部の窒素分圧を１気圧に調整する圧力調整工程とからなることを特徴とする。
The vacuum maintaining step is characterized in that the inside of the vacuum melting furnace has a degree of vacuum of 10 −3 torr (≈0.13 Pa) or less.
The nitrogen content adjusting step includes a nitrogen injecting step of injecting nitrogen gas into the vacuum melting furnace, and a pressure adjusting step of adjusting the nitrogen partial pressure inside the vacuum melting furnace to 1 atm. To do.
このように構成される本発明によると、安価な製造費用及び原材料費用で高い強度及び耐食性を有するオーステナイト系ステンレス鋳造材、鍛造材または圧延材の製造工程まで多様に適用することができる長所がある。 According to the present invention configured as described above, there is an advantage that it can be applied in various ways up to a manufacturing process of austenitic stainless cast material, forged material or rolled material having high strength and corrosion resistance at low manufacturing cost and raw material cost. .
本発明によるオーステナイト系ステンレス鋼は、引張強度が８５０ＭＰａ以上で均一延伸率が４５％以上であることが示された（表２参照）。また、１Ｍ ＮａＣｌ溶液で電位走査速度（ｄＶ／ｄｔ）２ｍＶ／ｓで電位を増加させながら両極の分極挙動を測定した結果、孔食が発生しないことから優れた耐食性を有することを確認した（表３参照）。 The austenitic stainless steel according to the present invention was shown to have a tensile strength of 850 MPa or more and a uniform stretch ratio of 45% or more (see Table 2). In addition, as a result of measuring the polarization behavior of both electrodes while increasing the potential with a 1M NaCl solution at a potential scanning speed (dV / dt) of 2 mV / s, it was confirmed that it has excellent corrosion resistance because pitting corrosion does not occur (Table 3).
したがって、本発明によるオーステナイト系ステンレス鋼は、炭素（Ｃ）を複合添加することによって、従来は高窒素鋼製造に不可避であった加圧工程を無くし、常圧の誘導溶解で製造することができ、安価な製造原価での合金製造を可能にするので、開発鋼種の価格競争力を向上させることができ、侵入型元素（Ｃ＋Ｎ、Ｃ／Ｎ）と置換型元素（Ｍｎ＋Ｃｒ、Ｍｎ／Ｃｒ、または０．５Ｗ＋Ｍｏ）の含量を制御することを通じて、８５０ＭＰａ以上の引張強度及び４５％以上の均一延伸率を有し、成形加工性が向上するのみならず優れた耐食性を示し、有害な合金元素であるニッケル（Ｎｉ）含量を最小限に抑えることによって生体適合性が向上するので、既存のオーステナイトステンレス鋼の適用分野及び高強度・高耐食性が求められる海洋構造物、淡水化設備、オイル及びガス設備／採掘用素材、運送機関用素材などに適用が可能であるのみならず、医療用生体材料、時計などの装身具を含む多様な機能性部品の製造にも有用である。 Accordingly, the austenitic stainless steel according to the present invention can be produced by induction melting at normal pressure by adding carbon (C) in a composite manner, eliminating the pressurization step that was unavoidable in the past for producing high nitrogen steel. Since it enables alloy production at a low production cost, the price competitiveness of the developed steel type can be improved, and interstitial elements (C + N, C / N) and substitutional elements (Mn + Cr, Mn / Cr, or By controlling the content of 0.5W + Mo), it has a tensile strength of 850 MPa or more and a uniform stretch ratio of 45% or more, which not only improves moldability but also exhibits excellent corrosion resistance and is a harmful alloy element Since biocompatibility is improved by minimizing the nickel (Ni) content, application fields of existing austenitic stainless steel and high strength and high corrosion resistance are required. Not only can it be applied to Western structures, desalination facilities, oil and gas facilities / mining materials, transportation engine materials, etc., but also manufacturing various functional parts including medical biomaterials and accessories such as watches. Also useful.
以下、実施例及び実験例を通じて本発明を詳しく説明する。但し、下記の実施例及び実験例は本発明を例示するだけのものであって、本発明の内容が下記の実施例によって限定されるのではない。
＜実施例１〜８＞本発明によるオーステナイト系ステンレス鋼の製造
本発明によるオーステナイト系ステンレス鋼の製造において、融点が高くて溶解が難しいクロム（Ｃｒ）はＦｅ−６０％Ｃｒ母合金を使用し、蒸気圧が低くて溶解時にガス（fume）生成及び偏析の憂慮があるマンガン（Ｍｎ）はＦｅ−５０％Ｍｎ母合金を使用した。
Hereinafter, the present invention will be described in detail through examples and experimental examples. However, the following examples and experimental examples merely illustrate the present invention, and the content of the present invention is not limited by the following examples.
<Examples 1-8> Production of austenitic stainless steel according to the present invention In the production of austenitic stainless steel according to the present invention, chromium (Cr), which has a high melting point and is difficult to dissolve, uses a Fe-60% Cr master alloy, Manganese (Mn), which has a low vapor pressure and has concerns about fume generation and segregation during melting, was an Fe-50% Mn master alloy.
図２及び図３に示したように、下記表１の成分比によって前記Ｆｅ−５０％Ｍｎ、Ｆｅ−６０％Ｃｒ、電解鉄、窒素含量制御のためのＦｅ−５８．８％Ｃｒ−６．６％Ｎ母合金、炭素含量制御のための７５．１％Ｍｎ−１７．４％Ｆｅ−６．８％Ｃ母合金、タングステン母合金及び／またはモリブデン母合金を真空溶解炉の内部に装入した（Ｓ１００）。以後、真空溶解炉の内部が１０−３ｔｏｒｒ以下の真空度に到達するまで脱気した後、真空を維持しながら（Ｓ２００）、前記真空溶解炉を加熱して真空溶解炉に装入された母合金及び電解鉄を溶融させた（Ｓ３００）。前記母合金及び電解鉄を溶融した後、前記真空溶解炉の内部に窒素ガスを注入して（Ｓ４２０）真空溶解炉の内部の窒素分圧が１気圧になるように圧力を調整して（Ｓ４４０）窒素含量を調整した（Ｓ４００）。以後、電磁誘導撹拌により合金元素の偏析を除去するために溶融合金を撹拌し（Ｓ５００）、溶融合金撹拌工程（Ｓ５００）中、母合金及び電解鉄が溶解して形成される溶湯の温度が１，４５０℃に到達したら真空溶解炉の内部から出湯して鋳塊を形成した（Ｓ６００）。形成された鋳塊を熱間圧延により板材や管、棒、細線などに製造し（Ｓ７００）、水冷処理して機械的特性及び耐食性に有害な炭化物の析出を抑制した（Ｓ８００）。
＜比較例１〜３＞一般的なオーステナイト系ステンレス鋼
一般的なオーステナイト系ステンレス鋼（ＡＩＳＩ３０４、ＡＩＳＩ３１６、ＡＩＳＩ３１６Ｌ）を使用した。
＜比較例４〜５＞
ベルンスらのグループが以前に発表した特許出願（ＰＣＴ／ＥＰ２００５／００８９６０）の製造方法でオーステナイト系ステンレス鋼を製造した。
As shown in FIG. 2 and FIG. 3, the Fe-50% Mn, Fe-60% Cr, electrolytic iron, and Fe-58.8% Cr-6. 6% N master alloy, 75.1% Mn-17.4% Fe-6.8% C master alloy, tungsten master alloy and / or molybdenum master alloy for carbon content control are charged into the vacuum melting furnace. (S100). Thereafter, after the inside of the vacuum melting furnace was deaerated until the degree of vacuum reached 10 −3 torr or less, the vacuum melting furnace was heated and charged into the vacuum melting furnace while maintaining the vacuum (S200). The mother alloy and electrolytic iron were melted (S300). After the mother alloy and electrolytic iron are melted, nitrogen gas is injected into the vacuum melting furnace (S420), and the pressure is adjusted so that the nitrogen partial pressure inside the vacuum melting furnace is 1 atm (S440). ) The nitrogen content was adjusted (S400). Thereafter, the molten alloy is stirred to remove segregation of the alloy elements by electromagnetic induction stirring (S500), and the temperature of the molten metal formed by melting the mother alloy and electrolytic iron during the molten alloy stirring step (S500) is 1 When the temperature reached 450 ° C., hot water was discharged from the inside of the vacuum melting furnace to form an ingot (S600). The formed ingot was manufactured into a plate material, a tube, a rod, a fine wire, etc. by hot rolling (S700), and water-cooled to suppress precipitation of carbides harmful to mechanical properties and corrosion resistance (S800).
<Comparative Examples 1-3> General austenitic stainless steel General austenitic stainless steel (AISI304, AISI316, AISI316L) was used.
<Comparative Examples 4-5>
Austenitic stainless steel was manufactured by the manufacturing method of the patent application (PCT / EP2005 / 008960) previously published by Berns et al.
前記実施例及び前記比較例のオーステナイト系ステンレス鋼の組成を表１に示した。 Table 1 shows the compositions of the austenitic stainless steels of the examples and comparative examples.
前記の工程によって製造された実施例及び比較例の常温引張特性を表２に示した。
また、ベルンスらのグループが以前に開発した炭窒素複合添加オーステナイト系ステンレス鋼（比較例４〜５）と比較すると（降伏強度５００〜５３３ＭＰａ、引張強度９４０〜１０１９ＭＰａ、均一延伸率５９．０〜６２．８％）、同等のレベルの機械的特性を示すことが分かる。 Further, when compared with the carbon-nitrogen composite-added austenitic stainless steel (Comparative Examples 4 to 5) previously developed by Berns et al. Group (yield strength 500 to 533 MPa, tensile strength 940 to 1019 MPa, uniform stretch ratio 59.0 to 62). 8%), it can be seen that the same level of mechanical properties is exhibited.
したがって、本発明によるオーステナイト系ステンレス鋼は、一般的なオーステナイト系ステンレス鋼に比べてニッケル含量を最小限に抑えながら高強度の優れた機械的特性を示すので、従来のオーステナイト系ステンレス鋼の代替として使用することができる。
＜実験例２＞耐食性測定
本発明によるオーステナイト系ステンレス鋼の耐食性を測定するために、実施例と比較例のオーステナイト系ステンレス鋼の試験片を常温の１Ｍ ＮａＣｌ溶液に浸漬して電位走査速度（ｄＶ／ｄｔ）２ｍＶ／ｓで電位を増加させながら両極の分極挙動を観察し、孔食電位を測定して図４及び表３に示した。
Therefore, the austenitic stainless steel according to the present invention exhibits excellent mechanical properties with high strength while minimizing the nickel content as compared with general austenitic stainless steel, so that it can be used as an alternative to conventional austenitic stainless steel. Can be used.
<Experimental Example 2> Corrosion Resistance Measurement In order to measure the corrosion resistance of the austenitic stainless steel according to the present invention, test specimens of the austenitic stainless steels of Examples and Comparative Examples were immersed in a 1 M NaCl solution at room temperature, and the potential scanning speed (dV / Dt) The polarization behavior of both electrodes was observed while increasing the potential at 2 mV / s, and the pitting potential was measured and shown in FIG. 4 and Table 3.
したがって、本発明によるオーステナイト系ステンレス鋼は、一般的なオーステナイトステンレス鋼または従来の炭窒素複合添加オーステナイト系ステンレス鋼に比べてニッケル含量を最小限に抑えながら高耐食性の優れた機械的特性を示すので、従来のオーステナイト系ステンレス鋼の代替として使用することができる。 Therefore, the austenitic stainless steel according to the present invention exhibits excellent mechanical properties with high corrosion resistance while minimizing the nickel content, compared to general austenitic stainless steel or conventional austenitic stainless steel combined with carbon and nitrogen. It can be used as an alternative to conventional austenitic stainless steel.
このような本発明の範囲は、前記で例示した実施例に限定されず、前記のような技術範囲中で当業者において、本発明を基礎にする他の多くの変形が可能だろう。 The scope of the present invention is not limited to the embodiments exemplified above, and many other modifications based on the present invention will be possible to those skilled in the art within the above technical scope.
Ｓ１００：母合金装入工程
Ｓ２００：真空維持工程
Ｓ３００：母合金溶融工程
Ｓ４００：窒素含量調整工程
Ｓ４２０：窒素注入工程
Ｓ４４０：圧力調整工程
Ｓ５００：溶融合金撹拌工程
Ｓ６００：鋳塊形成工程
Ｓ７００：熱間圧延工程
Ｓ８００：水冷工程
S100: Master alloy charging step S200: Vacuum maintaining step S300: Master alloy melting step S400: Nitrogen content adjusting step S420: Nitrogen injection step S440: Pressure adjusting step S500: Molten alloy stirring step S600: Ingot forming step S700: Hot Rolling process S800: Water cooling process
Claims (10)
１５〜２０重量％のクロム（Ｃｒ）と、
２重量％以下のニッケル（Ｎｉ）と、
１〜４重量％のタングステン（Ｗ）と、
合計（Ｃ＋Ｎ）で０．６〜１．０重量％の炭素（Ｃ）及び窒素（Ｎ）と、
残部である鉄（Ｆｅ）及びその他の不可避な不純物と
からなることを特徴とする、炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナイト系ステンレス鋼。 8-12% by weight manganese (Mn);
15-20 wt% chromium (Cr),
Up to 2% by weight of nickel (Ni);
1-4 wt% tungsten (W),
A total (C + N) of 0.6 to 1.0% by weight of carbon (C) and nitrogen (N);
Characterized by comprising the iron (Fe) and other unavoidable impurities the balance, carbon-containing (C) and nitrogen (N) austenitic stainless steel having high strength and high corrosion resistance are added in combination.
１５〜２０重量％のクロム（Ｃｒ）と、
２重量％以下のニッケル（Ｎｉ）と、
１〜４重量％のタングステン（Ｗ）と、
２重量％以下のモリブデン（Ｍｏ）と、
合計（Ｃ＋Ｎ）で０．６〜１．０重量％の炭素（Ｃ）及び窒素（Ｎ）と、
残部である鉄（Ｆｅ）及びその他の不可避な不純物と
からなることを特徴とする、請求項１に記載の炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナイト系ステンレス鋼。 8-12% by weight manganese (Mn);
15-20 wt% chromium (Cr),
Up to 2% by weight of nickel (Ni);
1-4 wt% tungsten (W),
2 wt% or less of molybdenum (Mo);
A total (C + N) of 0.6 to 1.0% by weight of carbon (C) and nitrogen (N);
The austenite having high strength and high corrosion resistance to which carbon (C) and nitrogen (N) are added in combination, according to claim 1, wherein the balance is iron (Fe) and other inevitable impurities. Stainless steel.
ステンレス鋼。 The content of the nitrogen (N) is 0.3% by weight or more, and the carbon (C) and the nitrogen (N) according to claim 1 are combined and have high strength and high corrosion resistance. Austenitic stainless steel.
母合金を真空溶解炉に装入する母合金装入工程と、
前記母合金が装入された真空溶解炉を真空状態に維持する真空維持工程と、
前記真空溶解炉を加熱して母合金を溶融する母合金溶融工程と、
前記真空溶解炉の内部に窒素ガスを注入する窒素含量調整工程と、
溶融された母合金を撹拌する溶融合金撹拌工程と、
前記真空溶解炉の内部で撹拌された溶融合金を出湯して鋳塊を形成する鋳塊形成工程と、
形成された鋳塊を熱間圧延する工程と、
熱間圧延されたステンレス鋼を水冷処理して機械的特性及び耐食性に有害な炭化物の析出を抑制する工程と
を含んでなることを特徴とする方法。 A method of producing an austenitic stainless steel having high strength and high corrosion resistance to which carbon (C) and nitrogen (N) according to claim 1 are added in combination.
A mother alloy charging process for charging the mother alloy into a vacuum melting furnace;
Maintaining the vacuum melting furnace charged with the mother alloy in a vacuum state; and
A mother alloy melting step of melting the mother alloy by heating the vacuum melting furnace;
A nitrogen content adjusting step of injecting nitrogen gas into the vacuum melting furnace;
A molten alloy stirring step of stirring the molten mother alloy;
An ingot forming step of forming an ingot by discharging a molten alloy stirred in the vacuum melting furnace;
Hot rolling the formed ingot;
And a step of water-cooling the hot-rolled stainless steel to suppress precipitation of carbides harmful to mechanical properties and corrosion resistance.
前記真空溶解炉の内部の窒素分圧を１気圧に調整する圧力調整工程と
からなることを特徴とする、炭素（Ｃ）と窒素（Ｎ）が複合添加された高強度・高耐食性を有するオーステナイト系ステンレス鋼を製造する請求項８に記載の方法。 The nitrogen content adjustment step includes a nitrogen injection step of injecting nitrogen gas into the vacuum melting furnace,
Austenite having high strength and high corrosion resistance in which carbon (C) and nitrogen (N) are added in combination, characterized by comprising a pressure adjustment step of adjusting the nitrogen partial pressure inside the vacuum melting furnace to 1 atmosphere The method according to claim 8 , wherein the stainless steel is produced.
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| KR1020090063487A KR101089714B1 (en) | 2009-07-13 | 2009-07-13 | C+N austenitic stainless steel with high strength and corrosion resistance having tungsten and fabrication method thereof |
| KR10-2009-0063486 | 2009-07-13 | ||
| KR1020090063486A KR101089718B1 (en) | 2009-07-13 | 2009-07-13 | C+N austenitic stainless steel with high strength and corrosion resistance having tungsten and molybdenum, and fabrication method thereof |
| KR10-2009-0063487 | 2009-07-13 | ||
| PCT/KR2009/004642 WO2011007921A1 (en) | 2009-07-13 | 2009-08-20 | High strength / corrosion-resistant,.austenitic stainless steel with carbon - nitrogen complex additive, and method for manufacturing same |
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| EP2617839A1 (en) * | 2012-01-18 | 2013-07-24 | MeKo Laserstrahl-Materialbearbeitungen e.K. | Nickel-free iron alloy for stents |
| CN103266283A (en) * | 2013-05-17 | 2013-08-28 | 江苏星火特钢有限公司 | Non-magnetic stainless steel for ore selection equipment |
| EP2813906A1 (en) * | 2013-06-12 | 2014-12-17 | Nivarox-FAR S.A. | Part for clockwork |
| CH708231B1 (en) * | 2013-06-27 | 2017-03-15 | Nivarox Far Sa | Clock spring made of austenitic stainless steel. |
| EP2924514B1 (en) * | 2014-03-24 | 2017-09-13 | Nivarox-FAR S.A. | Clockwork spring made of austenitic stainless steel |
| CN104367362A (en) * | 2014-11-04 | 2015-02-25 | 无锡贺邦金属制品有限公司 | Alloy microscopy vascular clamp with antiallergic function |
| CN106148852A (en) * | 2015-04-02 | 2016-11-23 | 上海微创医疗器械（集团）有限公司 | A kind of alloy material and implantable medical devices |
| EP3147378A1 (en) * | 2015-09-25 | 2017-03-29 | The Swatch Group Research and Development Ltd. | Nickel-free austenitic stainless steel |
| EP3249059A1 (en) * | 2016-05-27 | 2017-11-29 | The Swatch Group Research and Development Ltd. | Method for thermal treatment of austenitic steels and austenitic steels thus obtained |
| US10639719B2 (en) | 2016-09-28 | 2020-05-05 | General Electric Company | Grain boundary engineering for additive manufacturing |
| EP3327151A1 (en) * | 2016-11-04 | 2018-05-30 | Richemont International S.A. | Resonator for a clock piece |
| CN113737091A (en) * | 2021-07-22 | 2021-12-03 | 洛阳双瑞特种装备有限公司 | Steel for low-magnetism high-strength corrosion-resistant fastener and fastener |
| CN114606430B (en) * | 2022-03-01 | 2023-05-12 | 兴机电器有限公司 | Low-carbon Fe-Mn-Al-Si TWIP steel and preparation method thereof |
| CN115652210B (en) * | 2022-11-07 | 2023-05-12 | 鞍钢股份有限公司 | Austenitic stainless steel billet with ultralow carbide content and manufacturing method thereof |
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