JP2002173720A - Ni BASED ALLOY EXCELLENT IN HOT WORKABILITY - Google Patents
Ni BASED ALLOY EXCELLENT IN HOT WORKABILITYInfo
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- JP2002173720A JP2002173720A JP2000370941A JP2000370941A JP2002173720A JP 2002173720 A JP2002173720 A JP 2002173720A JP 2000370941 A JP2000370941 A JP 2000370941A JP 2000370941 A JP2000370941 A JP 2000370941A JP 2002173720 A JP2002173720 A JP 2002173720A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は熱間加工性、更には耐粒
界腐食性、及び耐力に優れたNi基合金に関するものであ
り、特にインゴット又は鋳片の鍛造、熱間圧延などの熱
間加工時に割れ、破損等の発生が少なく熱間加工性等が
良好なNi基合金に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Ni-base alloy having excellent hot workability, furthermore, intergranular corrosion resistance and proof stress. The present invention relates to a Ni-based alloy which is free from cracking, breakage and the like during hot working and has good hot workability and the like.
【０００２】[0002]
【従来の技術】Ni基合金は耐食性及び耐熱性が優れた合
金であるため使用環境の厳しい条件で多用されている。
最近は更に材料の安全に対する信頼性要求が高くなって
いる。これらのNi基合金のうち例えばインコネル600は
原子炉の炉心材料として使用されているが、高い耐応力
腐食割れ性及び耐粒界腐食性等を要求されているため、
通常Nb等の安定化元素を添加して予め固溶Cを固定する
ことが行われている。2. Description of the Related Art Ni-base alloys are alloys having excellent corrosion resistance and heat resistance, and thus are often used under severe operating conditions.
Recently, reliability requirements for material safety have been further increased. Among these Ni-based alloys, for example, Inconel 600 is used as a core material of a nuclear reactor, but since high stress corrosion cracking resistance and intergranular corrosion resistance are required,
Usually, solid solution C is fixed in advance by adding a stabilizing element such as Nb.
【０００３】ところがNbを添加したNi基合金のインゴッ
トは熱間加工性が悪いため鍛造又は熱間圧延工程に通す
と割れ及び破損等の材料欠陥が生じる場合がある。これ
らの欠陥が生じると疵取りが不可欠となり製造歩留まり
が著しく低下する。However, Ni-based alloy ingots to which Nb has been added have poor hot workability, so that when subjected to forging or hot rolling, material defects such as cracks and breakage may occur. When these defects occur, the removal of the defects becomes indispensable, and the production yield is significantly reduced.
【０００４】熱間加工性を向上させるために特開昭63−
53235号公報ではNbCの溶体化熱処理を提案しており、特
開昭61−84348号公報ではB添加およびO含有量低減によ
る粒界偏析の低減を提案している。しかし、これらの発
明はいずれも10年以上も前に提案されたものであり、現
在この材料では新しい性能要求に対処できない。To improve hot workability, Japanese Patent Application Laid-Open
No. 53235 proposes a solution heat treatment of NbC, and Japanese Patent Application Laid-Open No. 61-84348 proposes reduction of grain boundary segregation by adding B and reducing the O content. However, each of these inventions was proposed more than ten years ago and currently this material cannot address new performance requirements.
【０００５】[0005]
【発明が解決しようとする課題】上記Nb入りNi基合金を
工業規模で製造する場合に、従来の合金では必ずしも安
定した熱間加工性が得られず熱間加工中に割れが発生す
る場合があった。そこで、本発明の目的はNbを含有する
Ni基合金における上記問題点を解消し、熱間加工性に優
れ、更には耐粒界腐食性と耐力も従来より優れたNi基合
金を提案することにある。When the above-mentioned Nb-containing Ni-based alloy is manufactured on an industrial scale, stable hot workability cannot always be obtained with a conventional alloy, and cracks may occur during hot working. there were. Therefore, an object of the present invention contains Nb
An object of the present invention is to propose a Ni-based alloy which solves the above-mentioned problems in a Ni-based alloy, is excellent in hot workability, and is also superior in the intergranular corrosion resistance and the proof stress.
【０００６】[0006]
【課題を解決するための手段】上記課題を解決するため
に本発明の第１の態様は、下記の成分組成(以下%とppm
は重量ベースである)を有することを特徴とする熱間加
工性に優れたNi基合金である。 (a)C：0.045％以下、Fe：3〜25％、Cr：14〜26％、Nb：
4％以下、N：0.005〜0.04％、Si：1.0％以下、Al：0.2
％以下、P：0.030％以下、Mn：1.0％以下、残部がNiと
不可避的不純物であり、(b)更に、S(ppm)とO(ppm)は、S
≦150ppmで、かつO（ppm）≦100−S／3.75である。Means for Solving the Problems In order to solve the above-mentioned problems, a first aspect of the present invention is a composition comprising the following components (% and ppm
Are based on weight), and are excellent in hot workability. (a) C: 0.045% or less, Fe: 3 to 25%, Cr: 14 to 26%, Nb:
4% or less, N: 0.005 to 0.04%, Si: 1.0% or less, Al: 0.2
% Or less, P: 0.030% or less, Mn: 1.0% or less, and the balance is Ni and inevitable impurities. (B) Further, S (ppm) and O (ppm)
≦ 150 ppm and O (ppm) ≦ 100−S / 3.75.
【０００７】発明の第２の態様は、前記成分組成が、
C：0.003〜0.045％、Nb：2〜4％、S：20ppm以下、O：20
ppm以下であることを特徴とする熱間加工性に優れたNi
基合金である。[0007] In a second aspect of the present invention, the component composition is as follows:
C: 0.003 to 0.045%, Nb: 2 to 4%, S: 20 ppm or less, O: 20
Ni with excellent hot workability characterized by being less than ppm
It is a base alloy.
【０００８】発明の第３の態様は、前記Alの含有量が0.
1％以下であることを特徴とする請熱間加工性に優れたN
i基合金である。[0008] In a third aspect of the present invention, the content of Al is 0.1.
N with excellent hot workability characterized by being 1% or less
i-based alloy.
【０００９】発明の第４の態様は、前記成分組成に加え
て更に、Bを0.01％以下含有することを特長とする熱間
加工性に優れたNi基合金である。A fourth aspect of the present invention is a Ni-base alloy excellent in hot workability, characterized by further containing B in an amount of 0.01% or less in addition to the above-mentioned component composition.
【００１０】発明の第５の態様は、更に、前記C量と熱
間加工後のオーステナイト結晶粒度番号（G.S.No.）と
の関係が、 G.S.No.≦0では、C≦0.005%、 0＜G.S.No.≦2では、C≦[0.0025×G.S.No.＋0.015]％ G.S.No.＞2では、C＜0.045％ であることを特徴とする熱間加工性に優れたNi基合金で
ある。In a fifth aspect of the invention, the relationship between the C content and the austenite grain size number (GSNo.) After hot working is as follows: GSNo. ≦ 0, C ≦ 0.005%, 0 <GSNo. When ≦ 2, C ≦ [0.0025 × GSNo. + 0.015]%. When GSNo.> 2, C <0.045%. This is a Ni-base alloy excellent in hot workability.
【００１１】発明の第６の態様は、更に、Nb／（C＋N）
が、前記G.S.No.が2〜5の範囲において、Nb／（C＋N）
≧[320−55×（G.S.No．）]／3であり、G.S.No.が5を超
え6以下の範囲においてはNb／（C＋N）≧15であること
を特徴とする熱間加工性に優れたNi基合金である。In a sixth aspect of the invention, the method further comprises the step of: Nb / (C + N)
However, when the GS No. is in the range of 2 to 5, Nb / (C + N)
≧ [320−55 × (GSNo.)] / 3, and Nb / (C + N) ≧ 15 when GSNo. Is more than 5 and 6 or less. It is a base alloy.
【００１２】[0012]
【発明の実施の形態】本発明の基本成分組成（以下％と
ppmは重量ベースである）について説明する。Cは本合金
の機械的強度の向上に寄与する成分である。含有量が多
すぎる場合は耐食性が悪くなるので上限は0.045％と
し、好ましくは0.040％以下（0％を含む）の含有量とす
る。なお、強度を確保するため0.003％以上が望まし
く、より望ましくは0.005％以上である。BEST MODE FOR CARRYING OUT THE INVENTION The basic component composition of the present invention (hereinafter referred to as%
ppm is on a weight basis). C is a component that contributes to improving the mechanical strength of the present alloy. If the content is too large, the corrosion resistance deteriorates, so the upper limit is made 0.045%, preferably the content is 0.040% or less (including 0%). In addition, 0.003% or more is desirable to secure the strength, and more desirably 0.005% or more.
【００１３】Feは靭性に寄与する成分である。含有量が
多すぎる場合は耐食性が劣化し易くなるので含有量の上
限は25％とする。なお、靭性を確保するため下限は3％
とし、好ましくは5％以上とする。[0013] Fe is a component that contributes to toughness. If the content is too large, the corrosion resistance tends to deteriorate, so the upper limit of the content is set to 25%. The lower limit is 3% to ensure toughness
And preferably at least 5%.
【００１４】Crは耐食性を発揮させるのに不可欠の元素
である。含有量が14％より少ないと耐食性が劣化する。
26％より多いと高温強度が高くなって加工が困難となる
ので14〜26％の範囲内とする。Cr is an element indispensable for exhibiting corrosion resistance. If the content is less than 14%, the corrosion resistance deteriorates.
If it is more than 26%, the high-temperature strength becomes high and processing becomes difficult, so the content is set in the range of 14 to 26%.
【００１５】Nbは固溶炭素（C）、及び固溶窒素（N）を
炭化物、及び窒化物として析出させ耐食性を向上させる
効果がある。ただし、含有量が多すぎると過剰に析出し
た析出物により粒界脆化が生じる場合があるので4％以
下とする。また、含有量が少なすぎると耐食性が悪くな
るので好ましくは2％以上含有する。Nbの含有量は、C及
びN含有量に応じて望ましくはNb／（C＋N）≧15であ
り、より好ましくは30以上、更に好ましくは60以上とな
るように含有するものとする。Nb has the effect of precipitating solid solution carbon (C) and solid solution nitrogen (N) as carbides and nitrides to improve corrosion resistance. However, if the content is too large, the precipitates excessively precipitated may cause grain boundary embrittlement, so the content is set to 4% or less. Further, if the content is too small, the corrosion resistance deteriorates. Therefore, the content is preferably 2% or more. The Nb content is desirably Nb / (C + N) ≧ 15 according to the C and N contents, more preferably 30 or more, and still more preferably 60 or more.
【００１６】Nは機械的強度、耐食性、及び耐粒界腐食
性の向上に有効である。含有量が0.04％を超えるとNの
固溶限に近づいてブローホールを生じ易くなるので0.04
％以下とする。なお、耐力を確保するため0.005％以上
とし、好ましくは0.01％以上とする。N is effective in improving mechanical strength, corrosion resistance, and intergranular corrosion resistance. If the content exceeds 0.04%, it approaches the solid solubility limit of N and blow holes are likely to occur.
% Or less. In addition, in order to ensure proof stress, the content is set to 0.005% or more, and preferably 0.01% or more.
【００１７】Alは脱酸材として添加され、酸素低減によ
り熱間加工性向上に寄与する。しかし、含有量が多すぎ
ると固溶Alが増加し、逆に熱間加工性が低下するととも
に脱酸生成物を巻き込み清浄度を劣化させるので0.2％
以下とする。より望ましくは0.1％以下である。Al is added as a deoxidizer and contributes to improvement of hot workability by reducing oxygen. However, if the content is too high, the amount of solute Al increases, and conversely, the hot workability decreases, and deoxidation products are involved.
The following is assumed. More preferably, it is 0.1% or less.
【００１８】Bは熱間加工性を改善するので含有量は0.0
1％以下とする。0.01％を超えると熱間加工性が劣化す
る。The content of B is 0.0% because B improves hot workability.
1% or less. If it exceeds 0.01%, hot workability deteriorates.
【００１９】Siは含有量が1.0％より多いと耐粒界腐食
性が劣化するので1.0％以下とする。If the content of Si is more than 1.0%, the intergranular corrosion resistance deteriorates, so the content is set to 1.0% or less.
【００２０】Pは含有量が0.003％より多いと耐粒界腐食
性、及び溶接性が劣化するので0.003％以下とする。If the content of P is more than 0.003%, intergranular corrosion resistance and weldability deteriorate, so the content of P is set to 0.003% or less.
【００２１】Mnは含有量が1.0％より多いと耐粒界腐食
性が劣化するので1.0％以下とする。If the content of Mn is more than 1.0%, the intergranular corrosion resistance deteriorates.
【００２２】本発明においては熱間加工性を改良する点
から、特にS（硫黄）とO（酸素）について特別の条件を
規定した。Ni基合金の熱間加工時に生じる割れ、及び破
損の原因は主として粒界破壊である。特にNb等を添加し
た場合にはNbC等が粒内及び粒界に析出する。その結
果、粒内強度の上昇と粒界強度の低下が生じて熱間加工
性が低下する。In the present invention, special conditions for S (sulfur) and O (oxygen) are specified in order to improve hot workability. The cause of cracking and breakage during hot working of Ni-based alloys is mainly grain boundary fracture. In particular, when Nb or the like is added, NbC or the like precipitates in the grains and at the grain boundaries. As a result, an increase in intragranular strength and a decrease in grain boundary strength occur, and the hot workability decreases.
【００２３】一方S、Oは粒界に偏析して粒界を脆化させ
る有害元素である。従来、低濃度での制御が困難であっ
たO、S、Alなどの合金成分組成が、近年の製錬技術の向
上に伴い低濃度に制御できるようになった。そこで本発
明者らは、OとSを同時に低減した場合に熱間加工性が著
しく向上し、特に、Nb入りNi基合金のように粒内強度が
大きい合金の割れも防止できることを見出した。On the other hand, S and O are harmful elements that segregate at grain boundaries and embrittle the grain boundaries. Conventionally, alloy components such as O, S, and Al, which had been difficult to control at a low concentration, can now be controlled to a low concentration with improvement in smelting technology in recent years. Thus, the present inventors have found that when O and S are simultaneously reduced, hot workability is remarkably improved, and in particular, it is possible to prevent cracking of an alloy having a large intragranular strength such as an Nb-containing Ni-based alloy.
【００２４】インコネル600合金を基本としてO含有量と
S含有量を変化させた合金を1050℃における熱間引張り
試験に供した。試験片の試験前後の断面減少率を調べて
絞り値に及ぼすO含有量とS含有量の影響を図１に示し
た。鍛造、及び熱間圧延等の熱間加工時に割れ、及び破
損等を起こさないためには絞り値は少なくとも60％以
上、より望ましくは70％以上、更に望ましくは80％以
上、最も望ましいのは90％以上である。O content based on Inconel 600 alloy
The alloys with different S contents were subjected to a hot tensile test at 1050 ° C. FIG. 1 shows the effects of the O content and the S content on the aperture value by examining the cross-sectional reduction ratio of the test piece before and after the test. In order to prevent cracking and breakage during hot working such as forging and hot rolling, the drawing value is at least 60% or more, more preferably 70% or more, further preferably 80% or more, and most preferably 90% or more. % Or more.
【００２５】図１からS含有量は150ppmを超えると絞り
値が60％以下となるので150ppm以下にする必要がある。
また、O含有量は100ppmより多い場合は絞り値が60％以
下となるので100ppm以下にする必要がある。好ましく
は、S≦150ppm、かつO（ppm）≦100−S／3.75である
（図１の実線の左側）。FIG. 1 shows that if the S content exceeds 150 ppm, the aperture value becomes 60% or less, so it must be 150 ppm or less.
When the O content is more than 100 ppm, the aperture value becomes 60% or less, so it is necessary to make the O content 100 ppm or less. Preferably, S ≦ 150 ppm and O (ppm) ≦ 100−S / 3.75 (left side of the solid line in FIG. 1).
【００２６】より望ましくはS≦100ppm、かつO≦100−S
／1.25である（図１の点線の左側）。更に望ましくは、
S≦50ppm、かつO≦60ppmである（図１の鎖線の左側）。
最も望ましい範囲はS≦20ppm、かつO≦20ppmである（図
１の最左端の範囲）。上記順に絞り値が向上するためで
ある。More preferably, S ≦ 100 ppm and O ≦ 100−S
/1.25 (left side of the dotted line in FIG. 1). More preferably,
S ≦ 50 ppm and O ≦ 60 ppm (left side of the chain line in FIG. 1).
The most desirable ranges are S ≦ 20 ppm and O ≦ 20 ppm (the leftmost range in FIG. 1). This is because the aperture value improves in the order described above.
【００２７】Alを添加すると脱酸材として作用して酸素
含有量が低減し熱間加工性が向上する。図２にAl含有量
の絞り値に与える影響を示した。しかし、Alが過剰に存
在すると熱間加工性が損なわれる。そこでAl含有量を0.
2％以下に制限し、OとSの熱間加工性に与える影響を調
査したところ、O≦20ppm、S≦20ppmの領域で熱間加工性
が極めて優れた合金が得られた。図２からも分かるよう
に熱間加工性は確実に改善されるのでAl含有量を0.1％
以下とすることが望ましい。Al添加により生じた脱酸生
成物を巻き込んで清浄度が低下することがあるためであ
る。When Al is added, it acts as a deoxidizing agent, reducing the oxygen content and improving hot workability. FIG. 2 shows the effect of the Al content on the aperture value. However, when Al is present in excess, hot workability is impaired. Therefore, the Al content is reduced to 0.
When the effect of O and S on hot workability was examined by limiting the content to 2% or less, an alloy having extremely excellent hot workability was obtained in the range of O ≦ 20 ppm and S ≦ 20 ppm. As can be seen from FIG. 2, the hot workability is definitely improved, so the Al content is 0.1%.
It is desirable to make the following. This is because the deoxidation product generated by the addition of Al may be involved and the cleanliness may decrease.
【００２８】上記熱間加工性に加え耐粒界腐食性を向上
させるためには以下のような限定が望ましい。即ち、粒
界腐食性はC含有量が高いほど劣るので、耐食性向上の
ためにはC含有量を低く押さえる必要がある。本発明者
らは、実際に粒界腐食を左右するのは粒界偏析した固溶
Cであると考え、結晶粒度を微細化し、単位粒界面積当
たりのC含有量を低下させることにより耐粒界腐食性が
向上すると推考した。In order to improve the intergranular corrosion resistance in addition to the hot workability, the following limitations are desirable. That is, the higher the C content, the lower the intergranular corrosion property. Therefore, it is necessary to keep the C content low to improve the corrosion resistance. The present inventors have determined that the grain boundary corrosion actually depends on the solid solution segregated at the grain boundary.
It was assumed that C was considered, and it was speculated that by reducing the crystal grain size and decreasing the C content per unit grain boundary area, intergranular corrosion resistance would be improved.
【００２９】そこで、結晶粒度とC含有量を制御するこ
とで優れた耐食性を有するNi基合金が得られることを知
見した。図３はインコネル合金を基本として、C含有量
および結晶粒度を変化させたときの粒界腐食試験におけ
る腐食速度dに対するC含有量とG.S.No.の関係を示した
図である。なお、ミクロ組織をリン酸又は蓚酸電解によ
り顕出した後、結晶粒径の測定はJISG0551に従って実施
した。Thus, it has been found that a Ni-based alloy having excellent corrosion resistance can be obtained by controlling the crystal grain size and the C content. FIG. 3 is a graph showing the relationship between the C content and the GS No. with respect to the corrosion rate d in the intergranular corrosion test when the C content and the crystal grain size are changed based on the Inconel alloy. After the microstructure was revealed by phosphoric acid or oxalic acid electrolysis, the crystal grain size was measured according to JIS G0551.
【００３０】粒界腐食試験は、3mm厚さ×15mm巾×50長
さの試験片を＃800まで湿式研磨し、50mm半径の曲げ加
工を施した後、50％H2SO4＋83gFe2(SO4)3の沸騰溶液中
で24hr煮沸して腐食速度dを求めた。その結果、G.S.No.
が2以上のときC含有量が0.045％まで添加しても最大腐
食速度dは500μm／day以下であり耐腐食性は良好であ
る。なお、好ましくはC含有量は0.043％以下とし、更に
好ましくは0.040％以下とする。In the intergranular corrosion test, a test piece of 3 mm thickness × 15 mm width × 50 length was wet-polished to # 800, bent to a radius of 50 mm, and then subjected to 50% H 2 SO 4 +83 g Fe 2 (SO 4 ) The corrosion rate d was determined by boiling in the boiling solution of 3 for 24 hours. As a result, GS No.
Is 2 or more, even if the C content is added up to 0.045%, the maximum corrosion rate d is 500 μm / day or less and the corrosion resistance is good. Preferably, the C content is 0.043% or less, more preferably 0.040% or less.
【００３１】0≦G.S.No.≦2の場合、C≦[0.0025×G.S.N
o.＋0.015]％を満足する範囲で最大腐食速度dは500μm
／day以下であり、耐粒界腐食性は良好である。C含有量
がこれより高い場合に単位粒界面積あたりの固溶Cが過
剰になって耐腐食性が低下する。When 0 ≦ GSNo. ≦ 2, C ≦ [0.0025 × GSN
o. + 0.015]%, the maximum corrosion rate d is 500μm
/ Day or less, and the intergranular corrosion resistance is good. If the C content is higher than this, the amount of solid solution C per unit grain boundary area becomes excessive, and the corrosion resistance decreases.
【００３２】G.S.No.≦0ではC≦0.005％を満足する必要
がある。C含有量がこれより高い場合、単位粒界面積あ
たりの固溶炭素（C）が過剰になり耐食性が低下する。
但し、C含有量は強度を確保するために好ましくは0.003
％以上とする。即ち、上記の関係をまとめると以下のよ
うになる。 G.S.No.≦0では、C≦0.005%、 0＜G.S.No.≦2では、C≦[0.0025×G.S.No.＋0.015]％ G.S.No.＞2では、C＜0.045％When GS No. ≦ 0, it is necessary to satisfy C ≦ 0.005%. If the C content is higher than this, the amount of dissolved carbon (C) per unit grain boundary area becomes excessive, and the corrosion resistance decreases.
However, the C content is preferably 0.003 to ensure strength.
% Or more. That is, the above relationship is summarized as follows. C ≦ 0.005% for GSNo. ≦ 0, C ≦ [0.0025 × GSNo. + 0.015]% for 0 <GSNo. ≦ 2, C <0.045% for GSNo.> 2
【００３３】結晶粒度を微細化するとそれだけで耐力向
上が可能であるが、析出物が存在する場合析出物の微細
化、均一分散による更なる析出強化が可能になる。Nb、
C及びNの添加は、析出強化と固溶強化により耐力を向上
させる効果がある。しかし、熱間加工後のオーステナイ
ト結晶粒度（以下単に結晶粒度という）が大きい場合、
析出物の多くは粒界で粗大化し、耐力向上に寄与しない
ばかりか粒界強度を減少させる。また、粒界強度と粒内
強度の差が大きくなるため熱間加工性が低下する。When the crystal grain size is reduced, the yield strength can be improved by itself. However, when a precipitate exists, the precipitation can be refined and further strengthened by uniform dispersion. Nb,
The addition of C and N has the effect of improving proof stress by precipitation strengthening and solid solution strengthening. However, when the austenite grain size after hot working (hereinafter simply referred to as grain size) is large,
Most of the precipitates are coarsened at the grain boundaries and do not contribute to the improvement of the proof stress, but also reduce the grain boundary strength. Further, the difference between the grain boundary strength and the intragranular strength increases, so that the hot workability decreases.
【００３４】そこで、本発明者らは、単位粒界面積あた
りの析出物量を制御するため、粒界面積の指標である結
晶粒度とNb／（C＋N）の関係を特定の範囲に制限するこ
とで、更に十分な耐力を有するNi基合金が得られること
を見出した。図４に耐力に与える結晶粒度番号とNb／
（C＋N）との関係を示した。In order to control the amount of precipitates per unit grain boundary area, the present inventors limit the relationship between the crystal grain size, which is an index of the grain boundary area, and Nb / (C + N) to a specific range. It has been found that a Ni-based alloy having more sufficient proof stress can be obtained. Figure 4 shows the grain size number and Nb /
The relationship with (C + N) was shown.
【００３５】図４において、0.2％耐力が240MPa以上で
あるとインコネル600の規格値を満足するので望ましい
値である。従って、Nb／（C＋N）が、G.S.No.が2〜5の
範囲において、Nb／（C＋N）≧[320−55×（G.S.No.）]
／3であり、G.S.No．が5を超える範囲においてはNb／
（C＋N）≧15であることが望ましい。In FIG. 4, a 0.2% proof stress of 240 MPa or more is a desirable value because it satisfies the standard value of Inconel 600. Therefore, Nb / (C + N) ≧ [320−55 × (GSNo.)] When Nb / (C + N) is in the range of GSNo.
/ 3 and GS No. Is more than 5, Nb /
It is desirable that (C + N) ≧ 15.
【００３６】以上述べた条件を満足することにより熱間
加工性、粒界腐食性および耐力に優れたNi基合金が得ら
れる。By satisfying the above conditions, a Ni-based alloy having excellent hot workability, intergranular corrosion and proof stress can be obtained.
【００３７】[0037]
【実施例】図５として示す表１に記載した成分組成のNi
基合金を大気誘導炉で溶解してインゴットを溶製し、次
いで鍛造又は熱間圧延した。表中の試料番号１〜１３は
本発明の合金、１４〜２０は比較例の合金である。得ら
れた熱間圧延板の表面割れ発生状態を観察した。その結
果を成分組成とともに表１に示した。表においてSiは0.
05〜0.5％、Pは0.001〜0.015％、Mnは0.02〜0.5％であ
る。本発明合金には表面割れは発生しておらず熱間加工
性が改善されている。EXAMPLE Ni of the component composition shown in Table 1 shown in FIG.
The base alloy was melted in an air induction furnace to produce an ingot, which was then forged or hot rolled. Sample numbers 1 to 13 in the table are alloys of the present invention, and 14 to 20 are alloys of comparative examples. The state of occurrence of surface cracks in the obtained hot-rolled sheet was observed. The results are shown in Table 1 together with the component compositions. In the table, Si is 0.
05 to 0.5%, P is 0.001 to 0.015%, and Mn is 0.02 to 0.5%. The alloy of the present invention has no surface cracks and has improved hot workability.
【００３８】図６として示す表２に記載した成分組成の
合金を大気誘導炉で溶解してインゴットを溶製し、次い
で通常の鍛造又は熱間圧延を実施した。表中試料番号１
〜６は本発明の合金、１４〜２０は比較例の合金であ
る。Si、P及びMnは表１と同じである。得られた熱間圧
延板について粒界腐食試験を行なって最大腐食速度を測
定した。その結果を結晶粒度番号と成分組成とともに表
２に示した。本発明合金は従来材による比較材と比較し
て熱間加工性と最大腐食速度が改善されている。An alloy having the composition shown in Table 2 shown in FIG. 6 was melted in an air induction furnace to produce an ingot, and then ordinary forging or hot rolling was performed. Sample number 1 in the table
6 to 6 are alloys of the present invention, and 14 to 20 are alloys of comparative examples. Si, P and Mn are the same as in Table 1. The obtained hot rolled sheet was subjected to a grain boundary corrosion test to measure the maximum corrosion rate. The results are shown in Table 2 together with the crystal grain size number and the component composition. The alloy of the present invention has improved hot workability and maximum corrosion rate as compared with the comparative material of the conventional material.
【００３９】図７として示す表３に記載した試料番号１
〜６は熱間加工性と耐力に優れた合金であり、１４〜２
０は比較例の合金である。Si、P及びMnは表１と同じで
ある。本発明の効果は明らかである。Sample No. 1 described in Table 3 shown in FIG.
Nos. 6 to 6 are alloys having excellent hot workability and proof stress, and 14 to 2
0 is the alloy of the comparative example. Si, P and Mn are the same as in Table 1. The effects of the present invention are clear.
【００４０】図８として示す表４に記載した試料番号１
〜６は熱間加工性、粒界腐食性及び耐力に優れた合金で
あり、１４〜２０は比較例の合金である。Si、P及びMn
は表１と同じである。本発明の効果は明らかである。Sample No. 1 described in Table 4 shown in FIG.
Nos. 6 to 6 are alloys excellent in hot workability, intergranular corrosion and proof stress, and 14 to 20 are alloys of comparative examples. Si, P and Mn
Is the same as in Table 1. The effects of the present invention are clear.
【００４１】[0041]
【発明の効果】以上述べたように、本発明のNi基合金は
少なくとも熱間加工性、更には、耐粒界腐食及び耐力に
優れており、各種原子炉構造部材などに適用できる有用
な合金である。また、本発明のNi基合金は熱間加工性に
優れるので、割れ、破損などの補修による歩留まり損失
が少なく生産性の向上と生産コストに多大な寄与をす
る。As described above, the Ni-based alloy of the present invention is excellent in at least hot workability, furthermore, excellent in intergranular corrosion resistance and proof stress, and is a useful alloy applicable to various reactor structural members. It is. Further, since the Ni-base alloy of the present invention is excellent in hot workability, the yield loss due to repair such as cracking and breakage is small, and it greatly contributes to improvement of productivity and production cost.
【図１】SとOの含有量が絞り値に与える影響を示す図で
ある。FIG. 1 is a diagram showing the effect of the contents of S and O on the aperture value.
【図２】Al含有量が絞り値に与える影響を示す図であ
る。FIG. 2 is a diagram showing the effect of the Al content on the aperture value.
【図３】腐食速度と結晶粒度との関係を示す図である。FIG. 3 is a diagram showing a relationship between a corrosion rate and a crystal grain size.
【図４】結晶粒度番号とNb／（C＋N）との関係を示す図
である。FIG. 4 is a diagram showing a relationship between a crystal grain size number and Nb / (C + N).
【図５】加工性に優れた本発明合金例を表１として示す
図である。FIG. 5 is a diagram showing an example of the alloy of the present invention having excellent workability as Table 1.
【図６】熱間加工性と耐粒界腐食性に優れた本発明合金
例を表２として示す図ある。FIG. 6 is a table showing an example of the alloy of the present invention excellent in hot workability and intergranular corrosion resistance as Table 2.
【図７】加工性と耐力とに優れた本発明合金例を表３と
して示す図である。FIG. 7 is a diagram showing, as Table 3, an example of the alloy of the present invention having excellent workability and proof stress.
【図８】加工性と耐力と耐粒界腐食性に優れた本発明合
金例を表４として示す図である。FIG. 8 is a diagram showing, as Table 4, examples of the alloy of the present invention which are excellent in workability, proof stress, and intergranular corrosion resistance.
Claims (6)
スである)を備えたことを特徴とする熱間加工性に優れ
たNi基合金。 (a) C：0.045％以下、Fe：3〜25％、Cr：14〜26％、 Nb：4％以下、N：0.005〜0.04％、Si：1.0％以下、 Al：0.2％以下、P：0.030％以下、Mn：1.0％以下、 残部がNiと不可避的不純物であり、(b) 更に、S(ppm)
とO(ppm)は、S≦150ppmで、かつ、O（ppm）≦100−S／
3.75である。1. A Ni-base alloy excellent in hot workability, characterized by having the following component composition (% and ppm are on a weight basis). (a) C: 0.045% or less, Fe: 3 to 25%, Cr: 14 to 26%, Nb: 4% or less, N: 0.005 to 0.04%, Si: 1.0% or less, Al: 0.2% or less, P: 0.030% or less, Mn: 1.0% or less, the balance is Ni and inevitable impurities. (B) S (ppm)
And O (ppm) are S ≦ 150 ppm, and O (ppm) ≦ 100−S /
3.75.
b：2〜4％、S：20ppm以下、O：20ppm以下であることを
特徴とする請求項１に記載の熱間加工性に優れたNi基合
金。2. The composition according to claim 1, wherein the composition is C: 0.003 to 0.045%, N
2. The Ni-base alloy having excellent hot workability according to claim 1, wherein b: 2 to 4%, S: 20 ppm or less, and O: 20 ppm or less.
を特徴とする請求項１又は２のいずれかに記載の熱間加
工性に優れたNi基合金。3. The Ni-based alloy having excellent hot workability according to claim 1, wherein the content of Al is 0.1% or less.
長とする請求項１〜３のいずれか１項に記載の熱間加工
性に優れたNi基合金。4. The Ni-base alloy according to claim 1, further comprising 0.01% or less of B.
テナイト結晶粒度番号（G.S.No.）が、 G.S.No.≦0では、C≦0.005%、 0＜G.S.No.≦2では、C≦[0.0025×G.S.No.＋0.015]％ G.S.No.＞2では、C＜0.045％ であることを特徴とする請求項１〜４のいずれか１項に
記載の熱間加工性に優れたNi基合金。5. The amount of C is C ≦ 0.005% when the austenite grain size number (GSNo.) After hot working is GSNo. ≦ 0, and C ≦ [0.0025 when 0 <GSNo. ≦ 2. × GSNo. + 0.015]% When GSNo.> 2, C <0.045%. The Ni-base alloy excellent in hot workability according to claim 1, wherein C <0.045%.
〜5の範囲において、Nb／（C＋N）≧[320−55×（G.S.N
o．）]／3であり、G.S.No.が5を超え6以下の範囲におい
てはNb／（C＋N）≧15であることを特徴とする請求項１
〜４のいずれか１項に記載の熱間加工性に優れたNi基合
金。6. Nb / (C + N) is GSNo.
Nb / (C + N) ≧ [320−55 × (GSN
o. )] / 3, and Nb / (C + N) ≧ 15 when the GS No. is more than 5 and 6 or less.
5. The Ni-base alloy excellent in hot workability according to any one of 4 to 4 above.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011162819A (en) * | 2010-02-05 | 2011-08-25 | Mitsubishi Materials Corp | Ni-BASED ALLOY, AND METHOD FOR PRODUCING Ni-BASED ALLOY |
| JP2011524007A (en) * | 2008-05-28 | 2011-08-25 | ウェスティングハウス エレクトリック スウェーデン アーベー | Spacer grid |
| CN112575227A (en) * | 2020-11-02 | 2021-03-30 | 抚顺特殊钢股份有限公司 | Manufacturing method of high-silicon nickel-based alloy cold-rolled sheet |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011094237A (en) * | 2010-12-13 | 2011-05-12 | Nippon Yakin Kogyo Co Ltd | Ni BASED ALLOY HAVING EXCELLENT HOT WORKABILITY |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6075543A (en) * | 1983-10-03 | 1985-04-27 | Toshiba Corp | Alloy for apparatus in high irradiation region |
| US4626408A (en) * | 1984-09-20 | 1986-12-02 | Nippon Yakin Kogyo Kabushiki Kaisha | Ni-based alloy excellent in intergranular corrosion resistance, stress corrosion cracking resistance and hot workability |
| JPH0684535B2 (en) * | 1984-12-27 | 1994-10-26 | 株式会社東芝 | Method for producing nickel-based alloy |
| JPS61288041A (en) * | 1985-06-14 | 1986-12-18 | Babcock Hitachi Kk | Ni-base alloy excellent in intergranular stress corrosion cracking resistance and pitting resistance |
| JPH01132731A (en) * | 1988-05-20 | 1989-05-25 | Nippon Yakin Kogyo Co Ltd | Ni-base alloy excellent in mechanical strength as well as in intergranular corrosion resistance and stress corrosion cracking resistance in high heat-affected zone in weld zone |
| JPH0570911A (en) * | 1991-09-17 | 1993-03-23 | Sumitomo Metal Ind Ltd | Heat treatment of ni-based alloy |
| JPH05140707A (en) * | 1991-11-19 | 1993-06-08 | Hitachi Ltd | Heat treating method for improving corrosion resistance of solid-solution strengthened ni base alloy |
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2000
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2011524007A (en) * | 2008-05-28 | 2011-08-25 | ウェスティングハウス エレクトリック スウェーデン アーベー | Spacer grid |
| US8958523B2 (en) | 2008-05-28 | 2015-02-17 | Westinghouse Electric Sweden Ab | Spacer grid |
| JP2011162819A (en) * | 2010-02-05 | 2011-08-25 | Mitsubishi Materials Corp | Ni-BASED ALLOY, AND METHOD FOR PRODUCING Ni-BASED ALLOY |
| CN112575227A (en) * | 2020-11-02 | 2021-03-30 | 抚顺特殊钢股份有限公司 | Manufacturing method of high-silicon nickel-based alloy cold-rolled sheet |
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