JPH0629459B2 - Nb (3) Method for producing austenitic stainless steel having excellent cryogenic properties after Sn formation heat treatment - Google Patents

Nb (3) Method for producing austenitic stainless steel having excellent cryogenic properties after Sn formation heat treatment

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Publication number
JPH0629459B2
JPH0629459B2 JP27937686A JP27937686A JPH0629459B2 JP H0629459 B2 JPH0629459 B2 JP H0629459B2 JP 27937686 A JP27937686 A JP 27937686A JP 27937686 A JP27937686 A JP 27937686A JP H0629459 B2 JPH0629459 B2 JP H0629459B2
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JP
Japan
Prior art keywords
heat treatment
stainless steel
austenitic stainless
steel
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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JP27937686A
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Japanese (ja)
Other versions
JPS63134627A (en
Inventor
謙三郎 瀧澤
晴男 梶
千里 石岡
正二 登根
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Kobe Steel Ltd
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Kobe Steel Ltd
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Priority to JP27937686A priority Critical patent/JPH0629459B2/en
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Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明はＮb3Ｓn生成熱処理後の極低温特性に優れたオ
ーステナイト系ステンレス鋼の製造方法に関し、さらに
詳しくは、超電導磁石の支持体に代表される極低温用構
造材料であって、使用に先立って冷間加工、Ｎb3Ｓn生
成熱処理が行なわれても極低温特性に優れたオーステナ
イト系ステンレス鋼の製造方法に関する。TECHNICAL FIELD The present invention relates to a method for producing austenitic stainless steel having excellent cryogenic properties after heat treatment for Nb 3 Sn formation, and more specifically, to a support for a superconducting magnet. The present invention relates to a method for producing an austenitic stainless steel, which is a structural material for cryogenic use, which is excellent in cryogenic properties even when cold working and heat treatment for producing Nb 3 Sn are performed prior to use.

［従来技術］ 一般に、超電導磁石はＮbＴi線より８テスラ程度の磁界
を発生できるが、それ以上の高磁界を発生させるために
はＮb3Ｓnに代表される化合物超電導体を利用すること
が有効であるとされている。[Prior Art] Generally, a superconducting magnet can generate a magnetic field of about 8 tesla from a NbTi wire, but in order to generate a magnetic field higher than that, it is effective to use a compound superconductor represented by Nb 3 Sn. It is said that there is.

しかし、超電導体が化合物であるため可塑性が悪いとい
う問題があり、そのため、Ｎb3Ｓn生成前に支持材料と
共に加工を行なう導体製造工程または超電導磁石の製造
工程の最後に、Ｎb3Ｓnを６００〜８００℃×５０〜３
００時間の熱処理によって生成させ、Ｎb3Ｓnの変形を
最小に抑制している。However, since the superconductor is a compound, it has a problem of poor plasticity. Therefore, at the end of the conductor manufacturing process or the superconducting magnet manufacturing process, in which Nb 3 Sn is processed together with the supporting material before Nb 3 Sn is produced, 600 to 600 Nb 3 Sn is added. 800 ° C x 50-3
It is generated by a heat treatment for 00 hours to suppress the deformation of Nb 3 Sn to the minimum.

従って、、構造材料は、Ｎb3Ｓnの生成熱処理を同時に
受けるため、時効されて延性、靭性の劣化が生じ、この
劣化は極低温において特に顕著になるという問題があ
る。Therefore, since the structural material is simultaneously subjected to the heat treatment for forming Nb 3 Sn, there is a problem that the ductility and toughness are deteriorated due to aging, and this deterioration becomes particularly remarkable at extremely low temperatures.

このような極低温における特性の劣化に対して、Ｎｉを
多量に含有させたインコロイ合金等が使用されている
が、非常に高価であるので安価なステンレス鋼が望まれ
ている。For such deterioration of characteristics at extremely low temperatures, incoloy alloys containing a large amount of Ni are used, but inexpensive stainless steel is desired because it is very expensive.

しかして、最近になってＮｉ、Ｃｒ系ステンレス鋼にＶ
を含有させて特性の改善を行なった例として特公昭６１
−０００４１６号公報により提案されているが、このＶ
を含有させた鋼は時効前の冷間加工により極低温下にお
ける延性が大幅に劣化するという問題があり、この冷間
加工を考慮した特性改善が重要な技術的に解決すべき問
題である。Recently, Ni and Cr-based stainless steels have been V
As an example of improving the characteristics by containing the
Although it is proposed by Japanese Patent Publication No. 0000416, this V
Steel containing C has a problem that the ductility at cryogenic temperature is significantly deteriorated by cold working before aging, and improvement of properties in consideration of this cold working is an important technical problem to be solved.

［発明が解決しようとする問題点］ 本発明は、上記に説明したような従来における極低温構
造用材料としての種々の問題点に鑑みなされたものであ
り、本発明者が鋭意研究を行なった結果、Ｎb3Ｓn等の
化合物系超電導磁石の構造材料で冷間加工が行なわれた
後、Ｎb3Ｓn生成熱処理を行っても、極低温において延
性、靭性に優れた極低温特性に優れたオーステナイト系
ステンレス鋼の製造方法を開発したものである。[Problems to be Solved by the Invention] The present invention has been made in view of various problems as a conventional cryogenic structural material as described above, and the present inventors have conducted extensive research. results, after the cold working is performed by the structure material compound superconducting magnet such as Nb 3 Sn, even if the Nb 3 Sn generated heat treatment, excellent cryogenic properties with excellent ductility, toughness at cryogenic temperatures austenite This is a development of a manufacturing method for stainless steel.

［問題点を解決するための手段］ 本発明に係るＮb3Ｓn生成熱処理後の極低温特性に優れ
たオーステナイト系ステンレス鋼の製造方法は、 (1) Ｃ 0.03wt％以下、Ｓｉ 0.1〜2.0wt％、 Ｍｎ 0.1〜20.0wt％、Ｐ 0.025wt％以下、 Ｓ 0.015wt％以下、Ｎｉ 3〜15wt％、 Ｃｒ12〜20wt％、Ｍｏ 0.5〜2.5wt％、 Ｎｂ 0.01〜0.18wt％、Ｎ 0.05〜0.25wt％ を含有し、かつ、 Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８） を満足し、残部Ｆｅおよび不可避不純物からなる鋼塊ま
たは鋼片を熱間圧延或いは熱間圧延、冷間圧延を行い、
次いで、１０００〜１１５０℃の温度において溶体化処
理を行った後、さらに、８２０〜９００℃の温度に加熱
することを特徴とするＮb3Ｓn生成熱処理後の極低温特
性に優れたオーステナイト系ステンレス鋼の製造方法を
第１の発明とし、 (2) Ｃ 0.03wt％以下、Ｓｉ 0.1〜2.0wt％、 Ｍｎ 0.1〜20.0wt％、Ｐ 0.025wt％、 Ｓ 0.015wt％以下、Ｎｉ 3〜15wt％、 Ｃｒ12〜20wt％、Ｍｏ 0.5〜2.5wt％、 Ｎｂ 0.01〜0.18wt％、Ｎ 0.05〜0.25wt％ を含有し、さらに、 Ｃａ、Ｃｅ、Ｚｒのうち選んだ１種または２種以上0.00
1〜0.100wt％ を含有し、かつ、 Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８） を満足し、残部Ｆｅおよび不可避不純物からなる鋼塊ま
たは鋼片を熱間圧延或いは熱間圧延、冷間圧延を行い、
次いで、１０００〜１１５０℃の温度において溶体化処
理を行った後、さらに、８２０〜９００℃の温度に加熱
することを特徴とするＮb3Ｓn生成熱処理後の極低温特
性に優れたオーステナイト系ステンレス鋼の製造方法を
第２の発明とする２つの発明よりなるものである。[Means for Solving Problems] A method for producing an austenitic stainless steel having excellent cryogenic properties after Nb 3 Sn formation heat treatment according to the present invention is (1) C 0.03 wt% or less, Si 0.1 to 2.0 wt. %, Mn 0.1 to 20.0 wt%, P 0.025 wt% or less, S 0.015 wt% or less, Ni 3 to 15 wt%, Cr 12 to 20 wt%, Mo 0.5 to 2.5 wt%, Nb 0.01 to 0.18 wt%, N 0.05 to 0.25 wt% and contains Ni + 0.5Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
8) is satisfied, and a steel ingot or a billet consisting of the balance Fe and unavoidable impurities is hot-rolled or hot-rolled, cold-rolled,
Next, solution treatment is performed at a temperature of 1000 to 1150 ° C., and then heating is performed to a temperature of 820 to 900 ° C., which is an austenitic stainless steel having excellent cryogenic properties after heat treatment for Nb 3 Sn formation. (2) C 0.03 wt% or less, Si 0.1 to 2.0 wt%, Mn 0.1 to 20.0 wt%, P 0.025 wt%, S 0.015 wt% or less, Ni 3 to 15 wt%, Cr12 to 20 wt%, Mo 0.5 to 2.5 wt%, Nb 0.01 to 0.18 wt%, N 0.05 to 0.25 wt%, and one or more selected from Ca, Ce and Zr 0.00
1 to 0.100 wt% and contains Ni + 0.5Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
8) is satisfied, and a steel ingot or a billet consisting of the balance Fe and unavoidable impurities is hot-rolled or hot-rolled, cold-rolled,
Next, solution treatment is performed at a temperature of 1000 to 1150 ° C., and then heating is performed to a temperature of 820 to 900 ° C., which is an austenitic stainless steel having excellent cryogenic properties after heat treatment for Nb 3 Sn formation. The present invention comprises two inventions, the manufacturing method of which is the second invention.

本発明に係るＮb3Ｓn生成熱処理後の極低温特性に優れ
たオーステナイト系ステンレス鋼の製造方法について以
下詳細に説明する。The method for producing an austenitic stainless steel having excellent cryogenic properties after Nb 3 Sn formation heat treatment according to the present invention will be described in detail below.

先ず、本発明に係るＮb3Ｓn生成熱処理後の極低温特性
に優れたオーステナイト系ステンレス鋼の製造方法（以
下本発明に係る鋼の製造方法ということがある。）にお
いて使用するオーステナイト系ステンレス鋼の含有成分
および成分割合について説明する。First, the austenitic stainless steel used in the method for producing an austenitic stainless steel having excellent cryogenic properties after Nb 3 Sn formation heat treatment according to the present invention (hereinafter sometimes referred to as the steel producing method according to the present invention) is used. The contained components and component ratios will be described.

Ｃはオーステナイトの安定化と耐力向上に必要な元素で
あるが、含有量が 0.03wt％を越えるような多量の含有
であるとＮb3Ｓn生成熱処理に炭化物を析出して延性、
靭性を劣化させるようになる。よって、Ｃ含有量は 0.0
3wt％以下とする。C is an element necessary for stabilizing austenite and improving yield strength, but if the content is too large to exceed 0.03 wt%, carbides are precipitated during Nb 3 Sn formation heat treatment and ductility,
It will deteriorate the toughness. Therefore, the C content is 0.0
3 wt% or less.

Ｓiは脱酸のためと高温における耐酸化性を改善する元
素であり、含有量が 0.1wt％未満ではこのような効果は
少なく、 2.0wt％を越えて多量に含有されると靭性を劣
化させる。よって、Ｓi含有量は 0.1〜2.0wt％とする。Si is an element for deoxidizing and improving the oxidation resistance at high temperature. If the content is less than 0.1 wt%, such an effect is small, and if it exceeds 2.0 wt%, the toughness deteriorates. . Therefore, the Si content is 0.1 to 2.0 wt%.

Ｍnはオーステナイトの安定化、Ｎの固溶限の上昇に有
効であるが、含有量が 0.1wt％未満ではこのような効果
は少なく、また、20.0wt％を越えて含有されるとＣｒと
の共存で時効中に脆いσ相が析出し、靭性を劣化させ
る。よって、Ｍn含有量は 0.1〜20.0wt％とする。Mn is effective for stabilizing austenite and increasing the solid solubility limit of N, but if the content is less than 0.1 wt%, such an effect is small, and if it exceeds 20.0 wt%, it does not react with Cr. When coexisting, a brittle σ phase precipitates during aging and deteriorates toughness. Therefore, the Mn content is 0.1 to 20.0 wt%.

ＰはＮb3Ｓn生成熱処理によりオーステナイト粒界に移
動、偏析し、粒界脆化を促進するため極力低く抑える必
要があるが、経済性を考慮してＰ含有量は 0.025wt％と
する。P moves to the austenite grain boundaries by the heat treatment for Nb 3 Sn formation, segregates, and promotes grain boundary embrittlement, so it is necessary to keep it as low as possible, but in view of economy, the P content is 0.025 wt%.

Ｓは鋼の熱間加工性、延性、靭性を劣化させる有害な元
素であり、Ｐと同様極力低く抑える必要があるが、経済
性を考慮してＳ含有量は 0.015wt％とする。S is a harmful element that deteriorates the hot workability, ductility, and toughness of steel, and it must be kept as low as P, but the S content is 0.015 wt% in consideration of economic efficiency.

Ｎiはオーステナイト安定化と延性、靭性の向上に有効
な元素で、特に、Ｎb3Ｓn生成熱処理後または冷間加工
＋Ｎb3Ｓn生成熱処理後における延性、靭性の劣化に対
して有効であり、オーステナイト組成を確保するため
に、 3wt％以上は含有させることが必要で、また、上記
した効果は 15wt％を越えて含有させると飽和し、か
つ、コスト上昇を招く。よって、Ｎi含有量は 3〜15wt
％とする。Ni austenitic stabilizer and ductility, in an element effective in improving the toughness, in particular, is effective for Nb 3 Sn generation after heat treatment or cold working + Nb 3 Sn ductility after generating the heat treatment, the toughness deterioration, austenite composition In order to secure the above, it is necessary to contain 3 wt% or more, and if the above-mentioned effect exceeds 15 wt%, it will be saturated and the cost will increase. Therefore, the Ni content is 3 to 15 wt.
%.

Ｃrは耐蝕性の面から含有量は 12wt％以上とする必要が
あり、しかし、 20wt％を越えた多量に含有させるとオ
ーステナイトを不安定にし、かつ、Ｍnとの共存で時効
中に脆いσ相の析出を起して靭性を劣化させる。よっ
て、Ｃr含有量は 12〜20wt％とする。From the viewpoint of corrosion resistance, the content of Cr must be 12 wt% or more. However, if it is contained in a large amount exceeding 20 wt%, austenite becomes unstable and, in the coexistence with Mn, the σ phase is fragile during aging. Cause precipitation and deteriorate toughness. Therefore, the Cr content is 12 to 20 wt%.

Ｍoは耐力を向上させるのに必要であり、かつ、Ｎbが含
有されている場合Ｎb3Ｓn生成熱処理中における原子拡
散を抑制し、耐時効性の向上に有効であり、含有量が
0.5wt％未満ではこのような効果は少なく、また、 2.5w
t％を越える多量の含有はコスト上昇につながる。よっ
て、Ｍo含有量は0.5〜2.5wt％とする。Mo is necessary to improve the proof stress, and when Nb is contained, it is effective in suppressing atomic diffusion during the heat treatment for Nb 3 Sn formation, and is effective in improving the aging resistance.
If it is less than 0.5 wt%, such an effect is small, and if it is 2.5 w
A large content of more than t% leads to cost increase. Therefore, the Mo content is 0.5 to 2.5 wt%.

Ｎbは炭素、窒素を固定して有害なＣr炭素化物が粒界に
析出するのを抑制するので耐時効性を高め、特に、冷間
加工材の粒界割れを防止する特性を有し、かつ、Ｍoと
の共存含有によりこのような効果が顕著となり、含有量
が 0.01wt％身では上記した効果は少なく、また、 0.18
wt％を越えて多量に含有させると強化元素の窒素を消費
して強化低下および靭性劣化を生じさせる。よって、Ｎ
b含有量は 0.01〜0.18wt％とする。Nb fixes carbon and nitrogen and suppresses harmful Cr carbonization from precipitating at the grain boundaries, so that the aging resistance is improved and, in particular, Nb has the property of preventing intergranular cracking in cold-worked materials. , And Mo together, such an effect becomes remarkable, and when the content is 0.01 wt%, the above effect is small.
If it is contained in a large amount in excess of wt%, the strengthening element nitrogen is consumed, resulting in deterioration of strengthening and deterioration of toughness. Therefore, N
The b content is 0.01 to 0.18 wt%.

Ｎはオーステナイトを安定化し、かつ、耐力向上に有効
な元素であり、含有量が 0.05wt％未満ではこのような
効果は少なく、また、 0.25wt％を越えて多量に含有さ
せると靭性の劣化と溶接欠陥の発生を招く。よって、Ｎ
含有量は 0.05〜0.25wt％とする。N is an element that stabilizes austenite and is effective for improving the yield strength. If the content is less than 0.05 wt%, such an effect is small, and if it is contained in excess of 0.25 wt%, the toughness deteriorates. This causes welding defects. Therefore, N
The content is 0.05 to 0.25 wt%.

Ｃa、Ｃe、Ｚrは鋼を清浄化し、介在物を微細化、球状
化し、靭性を向上させる元素であり、含有量が 0.001wt
％未満ではこのような効果は少なく、また、0.1wt％を
越えて多量に含有させるとかえって清浄化を悪くする。
よって、Ｃa、Ｃe、Ｚrの含有量は 0.001〜0.1wt％とす
る。Ca, Ce, and Zr are elements that clean steel, refine inclusions, make them spherical, and improve toughness, and their content is 0.001 wt.
If it is less than 0.1%, such an effect is small, and if it is contained in a large amount exceeding 0.1% by weight, the cleaning is rather deteriorated.
Therefore, the content of Ca, Ce, and Zr is set to 0.001 to 0.1 wt%.

Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８） は、極低温で延性、靭性の高い安定したオーステナイト
組織を得るために必要でありこれを満足しない成分系の
材料においては、冷間加工後或いはＮb3Ｓn生成熱処理
後オーステナイト中にマルテンサイトが生成し、極低温
での延性、靭性を大きく損なうことになる。Ni + 0.5Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
8) is necessary for obtaining a stable austenite structure with high ductility and toughness at extremely low temperatures, and in the case of a material of a component system that does not satisfy this, martensite is contained in austenite after cold working or after heat treatment for Nb 3 Sn formation. Is generated, and ductility and toughness at extremely low temperatures are greatly impaired.

本発明に係る鋼の製造方法によれば、上記した化学成分
を有する鋼塊または鋼片を熱間圧延或いは熱間圧延、冷
間圧延を行い、次いで、１０００〜１１５０℃の温度に
おいて溶体化処理を行った後、さらに、８２０〜９００
℃の温度に加熱することにより、Ｎb3Ｓn生成熱処理後
の極低温特性に優れたオーステナイト系ステンレス鋼が
製造される。According to the method for producing steel according to the present invention, a steel ingot or a steel slab having the above chemical composition is hot-rolled or hot-rolled, cold-rolled, and then solution heat-treated at a temperature of 1000 to 1150 ° C. And then 820-900
By heating to a temperature of ° C., austenitic stainless steel excellent in cryogenic properties after Nb 3 Sn generation heat treatment it is produced.

熱間圧延または熱間圧延、冷間圧延を行った後に、１０
００〜１１５０℃の温度で溶体化処理を行うのである
が、この温度が１０００℃未満であると析出物の固溶が
充分でなく、オーステナイト結晶粒が細かくなるため、
延性、靭性が劣化し、また、１１５０℃を越える温度で
溶体化処理を行うとオーステナイト結晶粒が粗大化が著
しく耐力の低下が大きくなる。10 after hot rolling or hot rolling, cold rolling
The solution treatment is performed at a temperature of 00 to 1150 ° C., but if this temperature is less than 1000 ° C., the solid solution of the precipitate is not sufficient and the austenite crystal grains become fine,
Ductility and toughness are deteriorated, and when the solution treatment is performed at a temperature exceeding 1150 ° C., the austenite crystal grains are significantly coarsened and the yield strength is greatly reduced.

さらに、このような溶体化処理後に８２０〜９００℃に
再加熱安定化熱処理するが、この安定化熱処理は、その
後の加工において行なわれる溶接或いはＮb3Ｓn生成熱
処理時にＣr炭窒化物の結晶粒界析出を抑制し、延性、
靭性の劣化を小さくするのに有効である。Furthermore, after such solution treatment, reheating and stabilizing heat treatment is performed at 820 to 900 ° C. This stabilizing heat treatment is performed at the grain boundary of Cr carbonitride during welding or Nb 3 Sn formation heat treatment performed in the subsequent processing. Suppresses precipitation, ductility,
It is effective in reducing deterioration of toughness.

真空溶解により鋼（第１表のＮｏ．１）を溶製し、鍛造
後、板厚３０mmに熱間圧延した。さらに、１１００℃の
温度で溶体化処理を行った鋼板を供試板とし、安定化熱
処理温度と−２６９℃の温度における破壊靭性Ｋ1c値と
の関係を調査した。その結果第１図に示す。この供試鋼
板はいずれも安定化熱処理後、７００℃×１００時間の
Ｎb3Ｓn生成熱処理が施されている。Steel (No. 1 in Table 1) was melted by vacuum melting, forged, and then hot rolled to a plate thickness of 30 mm. Further, using a steel plate solution-treated at a temperature of 1100 ° C. as a test plate, the relationship between the stabilizing heat treatment temperature and the fracture toughness K1c value at a temperature of −269 ° C. was investigated. The results are shown in FIG. Each of the test steel sheets was subjected to a stabilizing heat treatment and then a Nb 3 Sn formation heat treatment at 700 ° C. for 100 hours.

この第１図からも明らかなように、８２０〜９００℃の
温度範囲で熱処理を行った鋼は、Ｎb3Ｓn生成熱処理後
においても高い破壊靭性を示している。As is clear from FIG. 1, the steel heat-treated in the temperature range of 820 to 900 ° C. shows high fracture toughness even after the Nb 3 Sn formation heat treatment.

これは、８２０〜９００℃の温度に加熱することによ
り、球状のＮb炭窒化物が生成、安定化し、その後のＮb
3Ｓn生成熱処理（７００℃×１００時間）による延性、
靭性を阻害するＣr炭窒化物の粒界析出を抑制するため
と考えられる。This is because spherical Nb carbonitrides are generated and stabilized by heating to a temperature of 820 to 900 ° C.
3 Ductility by Sn heat treatment (700 ° C × 100 hours),
It is considered to suppress the grain boundary precipitation of Cr carbonitride which inhibits toughness.

［実施例］ 本発明に係るＮb3Ｓn生成熱処理後の極低温特性に優れ
たオーステナイト系ステンレス鋼の製造方法の実施例を
説明する。[Example] An example of a method for producing an austenitic stainless steel having excellent cryogenic properties after Nb 3 Sn formation heat treatment according to the present invention will be described.

実施例 第１表(1)に示す５種類の含有成分および含有割合の鋼
を真空溶解により溶製し、鍛造後、板厚３０mmの鋼板に
熱間圧延した。Example Steel of 5 kinds of contained components and contained ratios shown in Table 1 (1) was melted by vacuum melting, forged, and then hot rolled into a steel plate having a thickness of 30 mm.

この鋼板を使用し、所定の熱処理、熱間加工を行い、さ
らに、７００℃×１００時間のＮb3Ｓn生成熱処理を行
った後、引張り、破壊靭性試験片を採取し、−２６９℃
の温度での試験に供した。Using this steel sheet, predetermined heat treatment and hot working were performed, and further, Nb 3 Sn formation heat treatment was performed at 700 ° C x 100 hours, and then tensile and fracture toughness test pieces were sampled at -269 ° C.
It was subjected to the test at the temperature of.

また、板厚３０mm鋼板の一部を使用し、熱間圧延、冷間
圧延を行い、板厚１．５〜２．０mmの冷間圧延鋼板を製
造し、３０mm材と同様の処理を行った後、引張り試験片
を採取し、−２６９℃の温度で試験を実施した。Further, using a part of a steel plate having a thickness of 30 mm, hot rolling and cold rolling were carried out to manufacture a cold rolled steel plate having a thickness of 1.5 to 2.0 mm, and the same treatment as that for the 30 mm material was performed. Then, the tensile test piece was extract | collected and the test was implemented at the temperature of -269 degreeC.

なお、透磁率は低透磁率計により測定した。The magnetic permeability was measured with a low magnetic permeability meter.

第１表(1)のＮｏ．１〜８は本発明に係る鋼の製造方法
に使用する鋼と同一の鋼を用いて、製造条件(第１表
(2))を変化させたものである。No. 1 in Table 1 (1). 1 to 8 use the same steel as the steel used in the method for producing steel according to the present invention, and the production conditions (Table 1
It is a variation of (2)).

Ｎo.１、３、５、７材は本発明に係る鋼の製造方法を用
いて試作したものであり、Ｎo.２、４、６、８と比較し
て、延性、靭性の著しい向上が認められる。Nos. 1, 3, 5, and 7 materials were made by trial using the steel manufacturing method according to the present invention, and markedly improved in ductility and toughness as compared with Nos. 2, 4, 6, and 8. To be

Ｎo.９、１０材は同一鋼であるが、安定化熱処理が実施
されていないＮo.１０は、Ｎo.９材と比較して延性、靭
性が劣っている。Ｎo.１１、１２材についても同様のこ
とがいえる。The No. 9 and No. 10 materials are the same steel, but the No. 10 material that has not been subjected to the stabilizing heat treatment is inferior in ductility and toughness to the No. 9 material. The same can be said for No. 11 and No. 12 materials.

また、Ｎo.１３、１４材はＳＵＳ３０４Ｌ鋼であり、Ｍ
o、Ｎbが含有されていないため、安定化熱処理の有無に
拘わらず、延性、靭性が低い。Also, Nos. 13 and 14 are SUS304L steel, and M
Since it does not contain o and Nb, it has low ductility and toughness regardless of the presence or absence of stabilizing heat treatment.

Ｎo.１５、１６材は個々の成分範囲は満足しているが、
Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８）を満足しないため、オーステナイト中に強磁性体で
あるマルテンサイトが生成し、透磁率が高くなってい
る。このマルテンサイト生成のため延性、靭性が極めて
低い。No. 15 and 16 materials satisfy the individual component ranges,
Ni + 0.5Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
Since 8) is not satisfied, martensite, which is a ferromagnetic material, is generated in austenite, and the magnetic permeability is high. Due to this martensite formation, ductility and toughness are extremely low.

［発明の効果］ 以上説明したように、本発明に係るＮb3Ｓn生成熱処理
後の極低温特性に優れたオーステナイト系ステンレス鋼
の製造方法は上記の構成であるから、冷間加工およびＮ
b3Ｓn生成熱処理を行っても極低温特性に優れ、超電導
磁石の支持体に代表される極低温用構造材として好適な
オーステナイト系ステンレス鋼を製造することができる
という効果を有する。 [Effects of the Invention] As described above, since the method for producing an austenitic stainless steel having excellent cryogenic properties after Nb 3 Sn formation heat treatment according to the present invention has the above-described configuration, cold working and N are performed.
even if the b 3 Sn generated heat treatment excellent cryogenic properties, has the effect that it is possible to manufacture a suitable austenitic stainless steels as cryogenic structural materials typified by the support of the superconducting magnet.

【図面の簡単な説明】[Brief description of drawings]

第１図は−２９６℃での破壊靭性・Ｋ1cと安定化処理温
度との関係を示す図である。FIG. 1 is a graph showing the relationship between fracture toughness K1c at −296 ° C. and stabilization treatment temperature.

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】Ｃ 0.03wt％以下、Ｓｉ 0.1〜2.0wt％、 Ｍｎ 0.1〜20.0wt％、Ｐ 0.025wt％以下、 Ｓ 0.015wt％以下、Ｎｉ 3〜15wt％、 Ｃｒ12〜20wt％、Ｍｏ 0.5〜2.5wt％、 Ｎｂ 0.01〜0.18wt％、Ｎ 0.05〜0.25wt％ を含有し、かつ、 Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８） を満足し、残部Ｆｅおよび不可避不純物からなる鋼塊ま
たは鋼片を熱間圧延或いは熱間圧延、冷間圧延を行い、
次いで、１０００〜１１５０℃の温度において溶体化処
理を行った後、さらに、８２０〜９００℃の温度に加熱
することを特徴とするＮb3Ｓn生成熱処理後の極低温特
性に優れたオーステナイト系ステンレス鋼の製造方法。1. C 0.03 wt% or less, Si 0.1 to 2.0 wt%, Mn 0.1 to 20.0 wt%, P 0.025 wt% or less, S 0.015 wt% or less, Ni 3 to 15 wt%, Cr 12 to 20 wt%, Mo 0.5. Up to 2.5 wt%, Nb 0.01 to 0.18 wt%, N 0.05 to 0.25 wt%, and Ni + 0.5Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
8) is satisfied, and a steel ingot or a billet consisting of the balance Fe and unavoidable impurities is hot-rolled or hot-rolled, cold-rolled,
Next, solution treatment is performed at a temperature of 1000 to 1150 ° C., and then heating is performed to a temperature of 820 to 900 ° C., which is an austenitic stainless steel having excellent cryogenic properties after heat treatment for Nb 3 Sn formation. Manufacturing method. 【請求項２】Ｃ 0.03wt％以下、Ｓｉ 0.1〜2.0wt％、 Ｍｎ 0.1〜20.0wt％、Ｐ 0.025wt％、 Ｓ 0.015wt％以下、Ｎｉ 3〜15wt％、 Ｃｒ12〜20wt％、Ｍｏ 0.5〜2.5wt％、 Ｎｂ 0.01〜0.18wt％、Ｎ 0.05〜0.25wt％ を含有し、さらに、 Ｃａ、Ｃｅ、Ｚｒのうちから選んだ１種または２種以上
0.001〜0.100wt％ を含有し、かつ、 Ｎｉ＋0.5Ｍｎ＋30Ｃ＋30Ｎ＞2/3（Ｃｒ＋Ｍｏ＋Ｓｉ−
８） を満足し、残部Ｆｅおよび不可避不純物からなる鋼塊ま
たは鋼片を熱間圧延或いは熱間圧延、冷間圧延を行い、
次いで、１０００〜１１５０℃の温度において溶体化処
理を行った後、さらに、８２０〜９００℃の温度に加熱
することを特徴とするＮb3Ｓn生成熱処理後の極低温特
性に優れたオーステナイト系ステンレス鋼の製造方法。2. C 0.03 wt% or less, Si 0.1 to 2.0 wt%, Mn 0.1 to 20.0 wt%, P 0.025 wt%, S 0.015 wt% or less, Ni 3 to 15 wt%, Cr 12 to 20 wt%, Mo 0.5 to 2.5 wt%, Nb 0.01-0.18 wt%, N 0.05-0.25 wt%, and one or more selected from Ca, Ce and Zr.
Contains 0.001 to 0.100 wt% and Ni + 0.5 Mn + 30C + 30N> 2/3 (Cr + Mo + Si-
8) is satisfied, and a steel ingot or a billet consisting of the balance Fe and unavoidable impurities is hot-rolled or hot-rolled, cold-rolled,
Next, solution treatment is performed at a temperature of 1000 to 1150 ° C., and then heating is performed to a temperature of 820 to 900 ° C., which is an austenitic stainless steel having excellent cryogenic properties after heat treatment for Nb 3 Sn formation. Manufacturing method.
JP27937686A 1986-11-22 1986-11-22 Nb (3) Method for producing austenitic stainless steel having excellent cryogenic properties after Sn formation heat treatment Expired - Lifetime JPH0629459B2 (en)

Priority Applications (1)

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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP27937686A JPH0629459B2 (en) 1986-11-22 1986-11-22 Nb (3) Method for producing austenitic stainless steel having excellent cryogenic properties after Sn formation heat treatment

Publications (2)

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JPS63134627A JPS63134627A (en) 1988-06-07
JPH0629459B2 true JPH0629459B2 (en) 1994-04-20

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BR9200797A (en) * 1992-02-27 1993-06-15 Acos Villares Sa ENROLLED STAINLESS STEEL FOR SPRINGS
CN1110577C (en) * 1997-12-23 2003-06-04 Ati产权公司 Austenitic stainless steel containing niobium
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