JPS6211059B2 - - Google Patents
Info
- Publication number
- JPS6211059B2 JPS6211059B2 JP57166833A JP16683382A JPS6211059B2 JP S6211059 B2 JPS6211059 B2 JP S6211059B2 JP 57166833 A JP57166833 A JP 57166833A JP 16683382 A JP16683382 A JP 16683382A JP S6211059 B2 JPS6211059 B2 JP S6211059B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- alloy
- intergranular
- resistance
- corrosion resistance
- 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
Links
- 229910045601 alloy Inorganic materials 0.000 claims description 52
- 239000000956 alloy Substances 0.000 claims description 52
- 230000007797 corrosion Effects 0.000 claims description 52
- 238000005260 corrosion Methods 0.000 claims description 52
- 238000005336 cracking Methods 0.000 claims description 18
- 229910052757 nitrogen Inorganic materials 0.000 claims description 17
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 description 12
- 230000003628 erosive effect Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 229910001055 inconels 600 Inorganic materials 0.000 description 9
- 239000011651 chromium Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 208000005156 Dehydration Diseases 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000011324 bead Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 206010070834 Sensitisation Diseases 0.000 description 2
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 2
- 238000005536 corrosion prevention Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000008313 sensitization Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910003470 tongbaite Inorganic materials 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- SJKRCWUQJZIWQB-UHFFFAOYSA-N azane;chromium Chemical compound N.[Cr] SJKRCWUQJZIWQB-UHFFFAOYSA-N 0.000 description 1
- CXOWYMLTGOFURZ-UHFFFAOYSA-N azanylidynechromium Chemical compound [Cr]#N CXOWYMLTGOFURZ-UHFFFAOYSA-N 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Landscapes
- Arc Welding In General (AREA)
- Heat Treatment Of Nonferrous Metals Or Alloys (AREA)
Description
（産業上の利用分野）
本発明は、耐粒界腐食性、耐応力腐食割れ性及
び熱間加工性に優れるNi基合金に関するもので
あり、特に本発明は、高温水中での粒界型応力腐
食割れを改善したCrを含有するNi基合金に関す
るものである。
（従来の技術）
近年化学工業、エネルギー産業の発展によつて
装置材料の受ける使用環境は多岐にわたり厳しい
条件下で使用される場合が多くなつており、安全
性に対する信頼性要求の高まりと共に安定した耐
食性を有する材料が要求されている。このような
理由から、環境の厳しい条件下ではステンレス鋼
やNi基合金が広く使用されている。なかでも塩
化物環境における粒内応力腐食割れに対しては
Ni基合金の方がオーステナイトステンレス鋼よ
りも優れた抵抗性を有するが、高Ni合金にあつ
てはＣの固溶量が少ないため粒界が鋭敏化し易い
欠点があり、高温水中で粒界型応力腐食割れが懸
念される。
従来インコネル600の粒界腐食および粒界応力
腐食割れに対してはTiまたはNbなどの安定化元
素を添加して、固溶Ｃを予め固定する安定化熱処
理を施す対策がとられているが、溶接熱影響部、
特に高温熱影響部においては上記安定化効果が消
えて溶接時及びその後の歪取り焼鈍などの熱処理
により粒界が鋭敏化されることが少なくなかつ
た。上記粒界の鋭敏化は粒界に炭化クロムが析出
することにより粒界近傍においてCrが減少す
る、いわゆるCr欠乏に起因する現象である。従
つて実機を考慮した場合には溶接部をも考慮した
耐粒界腐食性並びに耐粒内及び耐粒界応力腐食割
れ性に優れる合金が必要であることが要望されて
いた。
1981年４月に行われた日本金属学会講演会の講
演概要集第268頁によれば、インコネル600合金の
耐粒界腐食性改善のためには、Ｃを0.01％以下に
するか、あるいはNbを添加することが有効であ
ると記載され、さらにＮは粒界鋭敏化を促進する
ので有害であると記載されている。しかしながら
この合金はＣおよびＮの含有量が低くなると機械
的強度が低くなり、0.2％耐力はインコネル600の
規格である25Kg／mm2を下廻るという欠点がある。
また1982年５月に行われた腐食防食協会春期学
術講演大会の講演概要集第160頁には、インコネ
ル600合金の溶着金属の耐粒界腐食性に対してNb
およびNiが有効であることが記載されている。
しかしながら、この溶着金属は耐力を維持するた
めＣを0.04％以上にするとNbを多量に添加しな
ければならず、コストアツプおよび熱間加工性、
溶接性劣化などの原因になる。
（発明が解決しようとする問題点）
本発明は、従来のインコネル600、ならびに上
記日本金属学会および腐食防食協会の講演会で発
表された前記合金の有する欠点を除去し、さらに
改良した合金を提供することを目的とするもので
あり、特許請求の範囲記載の合金を提供すること
によつて前記目的を達成することができる。すな
わち本発明は、従来のインコネル600合金をベー
スとしてその機械的強度を維持しつつ、溶接熱影
響部をも含めた耐粒界腐食性及び耐粒界応力腐食
割れ性を改善した合金を提供するものである。
（問題点を解決するための手段）
本発明者らは、インコネル600合金組成をベー
スとしてNbとＣの含有量を
％Nb100（％Ｃ−0.005）
にコントロールすることにより溶接部を含めた耐
粒界腐食性及び耐粒界応力腐食割れ性を改善し、
またＣ，Ｎを％Ｃ＋％Ｎ≧0.04％にコントロール
することにより、機械的強度を高めた合金を得る
ことに成功した。すなわち、耐粒界腐食性に対し
てはNbを添加すると共に、Ｎの添加が有効であ
ることを新規に知見し、さらにＮは機械的強度に
有効であることをも知見した。
従来、ＮはＣと同様にCrと化合してクロム窒
化物として粒界に析出して粒界が鋭敏化する原因
となるために有害であるとして極めて低くコント
ロールされていたが、本発明者らは、クロム窒化
物の析出挙動はクロム炭化物のそれと著しく異な
り、むしろ耐粒界腐食性に有効であること、また
Ｎは機械的強度を高めるのに有効であることに着
目して、従来有害であると言われていたＮを積極
的に添加して機械的強度を損なうことなく耐粒界
腐食性、耐粒界応力腐食割れ性に優れるNi基合
金に想到して本発明を完成した。すなわち本発明
合金は従来のインコネル600に比べて機械的強度
は同一水準であるか又は上廻り、かつ耐粒界腐食
性及び耐応力腐食割れ性の点において優れた合金
である。
（実施例）
次に本発明を実験データについて説明する。
第１表に成分組成を示す本発明合金１，２と比
較合金３，４をそれぞれ大気誘導炉で溶解して６
Kg鋼塊とし、鍛造によつて厚さ10mm、幅70mmにし
素材熱処理として1100℃×1h加熱後水冷し、さ
らに870℃×2h加熱後水冷した。かくして得られ
た鋼片を機械試験に供した。一方耐食性試験用と
して第１図に示すように開先加工して多層肉盛
し、600℃×20h熱処理した後空冷し、さらに500
℃×40h熱処理後空冷した鋼片を作つた。溶接は
TIG溶接で行い溶接フイラーメタルの成分組成は
第２表のものを用いた。試験片はいずれも溶接部
断面を切り出し、最終湿式＃800まで研摩した。
第３表に0.2％耐力、粒界腐食試験及び高温水応
力腐食割れ試験のそれぞれの結果を示す。
粒界腐食及び高温水応力腐食割れ試験後試験片
の断面を光学顕微鏡で観察し、粒界腐食の場合は
最大侵食度ｄを測定し、また高温水応力腐食割れ
の場合は割れの有無を調べた。
(Field of Industrial Application) The present invention relates to a Ni-based alloy that has excellent intergranular corrosion resistance, stress corrosion cracking resistance, and hot workability. This invention relates to a Cr-containing Ni-based alloy that has improved corrosion cracking. (Conventional technology) Due to the development of the chemical and energy industries in recent years, equipment materials are being used in a wide variety of environments and are often used under harsh conditions. Materials with corrosion resistance are required. For these reasons, stainless steel and Ni-based alloys are widely used in harsh environmental conditions. Among these, for intragranular stress corrosion cracking in chloride environments,
Although Ni-based alloys have better resistance than austenitic stainless steel, high-Ni alloys have the disadvantage that grain boundaries tend to become sharp due to the small amount of solid solution of C, and grain boundary formation occurs in high-temperature water. There is a concern about stress corrosion cracking. Conventionally, measures have been taken to prevent intergranular corrosion and intergranular stress corrosion cracking in Inconel 600 by adding stabilizing elements such as Ti or Nb and performing stabilizing heat treatment to pre-fix solid solution C. weld heat affected zone,
Particularly in the high-temperature heat-affected zone, the above-mentioned stabilizing effect disappears, and grain boundaries often become sensitized during welding and subsequent heat treatment such as strain relief annealing. The grain boundary sensitization described above is a phenomenon caused by so-called Cr deficiency, in which Cr decreases near the grain boundaries due to the precipitation of chromium carbide at the grain boundaries. Therefore, in consideration of actual equipment, there has been a need for an alloy that has excellent intergranular corrosion resistance and intragranular and intergranular stress corrosion cracking resistance in consideration of welded parts. According to page 268 of the abstracts of the Japan Institute of Metals lecture held in April 1981, in order to improve the intergranular corrosion resistance of Inconel 600 alloy, it is necessary to reduce C to 0.01% or less, or add Nb to 0.01% or less. It is described that adding N is effective, and furthermore, it is described that N is harmful because it promotes grain boundary sensitization. However, this alloy has the disadvantage that the lower the C and N contents, the lower the mechanical strength, and the 0.2% yield strength is lower than the 25 kg/mm 2 standard for Inconel 600. In addition, on page 160 of the lecture summary collection of the Spring Academic Conference of the Corrosion Prevention Association held in May 1982, Nb
It is stated that Ni and Ni are effective.
However, in order to maintain the yield strength of this weld metal, if the C content is increased to 0.04% or more, a large amount of Nb must be added, resulting in increased costs and poor hot workability.
This may cause deterioration of weldability. (Problems to be Solved by the Invention) The present invention eliminates the drawbacks of the conventional Inconel 600 and the alloys presented at the above-mentioned lectures of the Japan Institute of Metals and Corrosion Prevention Association, and provides a further improved alloy. This object can be achieved by providing the alloy described in the claims. That is, the present invention provides an alloy based on the conventional Inconel 600 alloy that maintains its mechanical strength while improving intergranular corrosion resistance including the weld heat affected zone and intergranular stress corrosion cracking resistance. It is something. (Means for solving the problem) The present inventors have improved the grain resistance including the welded part by controlling the Nb and C contents to %Nb100 (%C - 0.005) based on the Inconel 600 alloy composition. Improves interfacial corrosion resistance and intergranular stress corrosion cracking resistance,
Furthermore, by controlling C and N to %C+%N≧0.04%, we succeeded in obtaining an alloy with increased mechanical strength. That is, it was newly discovered that adding Nb as well as N is effective for intergranular corrosion resistance, and it was also discovered that N is effective for improving mechanical strength. In the past, N was controlled at extremely low levels as it was considered harmful because, like C, it combines with Cr and precipitates at grain boundaries as chromium nitride, causing the grain boundaries to become more sensitive. focused on the fact that the precipitation behavior of chromium nitride is significantly different from that of chromium carbide, and that it is effective in intergranular corrosion resistance, and that N is effective in increasing mechanical strength. The present invention was completed by actively adding N, which was said to be present, to create a Ni-based alloy that has excellent intergranular corrosion resistance and intergranular stress corrosion cracking resistance without impairing mechanical strength. In other words, the alloy of the present invention has mechanical strength that is at the same level or higher than that of the conventional Inconel 600, and is superior in terms of intergranular corrosion resistance and stress corrosion cracking resistance. (Example) Next, the present invention will be explained using experimental data. Inventive alloys 1 and 2 and comparative alloys 3 and 4, whose compositions are shown in Table 1, were melted in an atmospheric induction furnace.
A Kg steel ingot was forged to a thickness of 10 mm and a width of 70 mm. As a material heat treatment, it was heated at 1100°C for 1 hour and then cooled with water, and further heated at 870°C for 2 hours and cooled with water. The thus obtained steel pieces were subjected to mechanical tests. On the other hand, for corrosion resistance testing, as shown in Figure 1, the grooves were prepared and multi-layered, heat treated at 600°C for 20 hours, air cooled, and
A steel billet was made which was heat treated for 40 hours at ℃ and then air cooled. Welding is
TIG welding was performed and the composition of the welded filler metal was as shown in Table 2. For each test piece, a cross section of the welded part was cut out and wet-polished to a final #800.
Table 3 shows the results of the 0.2% proof stress, intergranular corrosion test, and high temperature water stress corrosion cracking test. After intergranular corrosion and high-temperature water stress corrosion cracking tests, observe the cross section of the specimen with an optical microscope, and in the case of intergranular corrosion, measure the maximum degree of erosion d, and in the case of high-temperature water stress corrosion cracking, examine the presence or absence of cracks. Ta.
【表】【table】
【表】【table】
【表】
第３表によれば、本発明合金１，２の機械的性
質すなわち0.2％耐力（Kg／mm2）はインコネル600
の0.2％耐力規格である25Kg／mm2よりも何れも大
きく、かつ比較合金３，４のそれに比べても大き
いことが判る。粒界腐食試験によれば本発明合金
１，２の最大侵食度ｄは何れも500μｍ／day以
下と極めて小さく良好であるが、比較合金３，４
のそれは何れも1500μｍ／day以上と極めて大き
かつた。また、高温水応力腐食割れ試験（CBB
テスト）による結果では、本発明合金１，２は何
れも割れがなく良好であるが、比較合金３，４は
何れも割れが発生した。
（作用）
次に、各成分組成の作用について詳明に説明す
る。
第２図はNb量をそれぞれ０％、0.5％、1.5％、
2.3％含有する場合の粒界腐食最大侵食度ｄに及
ぼす含有Ｃ量の影響を示す図であり、最大侵食度
ｄが500μｍ／day以下になる限界Ｃ量はNb添加
量の増加とともに大きくなる。
第３図は、第２図においてｄ500μｍ／day
になる限界Ｃ量とそのときのNb量の相関関係を
示す図であり、同図中に示す直線はN0.01％以上
の場合の％Nb／（％Ｃ−0.005）＝100の関係を示
し、前記直線の左側の斜線を施した領域、すなわ
ち％Nb／（％Ｃ−0.005）100の領域において
はｄは500μｍ／day以下であり、前記直線の右
側の領域、すなわち％Nb／（％Ｃ−0.005）＜100
の領域においてはｄは500μｍ／dayより大であ
ることが判る。同図においてＣが0.045％より大
きいときに、ｄを500μｍ／day以下にするには
Nb量を４％より多く含有させる必要があるが、
このように多量のNbを含有させると熱間加工性
が劣化して生産性が低下する。
第４図は溶接部ならびに熱影響部のナイフライ
ンアタツク侵食度に及ぼすＮ，Ti添加効果の実
験結果を示す図であり、横軸はビードからの距
離、縦軸は侵食度を示す。曲線はNb1.6％を含
有させた合金、曲線は上記量のNbのほかに
N0.029％を含有させた本発明合金１、曲線は
上記量のNbとＮのほかにTiを0.26％含有させた
本発明合金２である。ビードからの距離の長い所
ではいずれの場合も侵食は殆どないが短い所では
Nbのみ含有した合金は侵食度が最も大きいが
0.029％Ｎ添加によつて侵食度が小さくなる。ま
た、0.028％Ｎおよび0.26％Ti添加によつて更に
侵食度が小さくなり、ＮおよびTiの添加によつ
て耐ナイフラインアタツクが改善される。
第５図はインコネル600合金を基本とし、Ｎを
0.03％を含有させ、数種の他の含有元素とその含
有量を変化させた合金Ａ〜Ｃについての加熱温度
と絞りとの関係を示す図である。同図中、合金Ａ
はS0.005％を含有する比較合金、合金Ｂは
S0.0004％とNb2.5％を含有する本発明合金、合
金ＣはS0.004％とNb2.5％を含有する比較合金で
ある。
同図によれば、本発明合金Ｂのように極低Ｓ化
（S0.0010以下）によつて熱間加工性が優れ、1300
℃の高温でもほぼ100％の絞りを示す。また1100
℃近傍の絞りをみると本発明合金Ｂは比較合金Ａ
及びＣよりはるかに上廻ることが判る。
第６図は合金のＣとＮとの和と0.2％耐力σ0.2
との関係を示す図であり、硬さ及び耐力はＣとＮ
との和が大きい程大きくなり、例えばインコネル
600の0.2％耐力の規格である25Kg／mm2以上を満足
するためには、ＣとＮとの和は0.04％以上必要で
あることが同図より判る。
次に本発明の合金において成分組成を限定する
理由を説明する。
Ｃは0.045％より多いと溶接部の耐食性の劣化
を防止するためのNbの含有量を多くしなければ
ならず、そうすると熱間加工性が劣化するので、
Ｃは0.045％以下にする必要があり、熱間加工性
の点では0.030％以下のとき最も良い結果が得ら
れれる。
Siは0.5％より多いと耐粒界腐食性が劣化する
ので、Siは0.5％以下にする必要がある。
Mnは1.0％より多いと耐粒界腐食性が劣化する
ので、Mnは1.0％以下にする必要がある。
Ｐは少ないほど好ましく、不可避的に混入する
元素であるが0.030％より多いと耐粒界腐食性及
び溶接性が劣化するので、Ｐは0.030％以下にす
る必要がある。
ＳはＰと同様不可避的に混入する元素であり少
ないほど好ましく、0.0010％より多いと熱間加工
性が著しく劣化するので、Ｓは0.0010％以下にす
る必要がある。
Crは耐食性を発揮させるのには不可欠の元素
であり、Crは14％より少ないと耐食性が劣化
し、一方17％より多いと高温強度が高くなり製造
性が低下するので、Crは14〜17％の範囲内にす
る必要がある。
Feは素地に固溶し金属間化合物の析出を抑え
る効果があり、６％より少ないとその効果が小さ
くなり、10％を超えると耐食性や機械的強度が劣
化するので、Feは６〜10％の範囲内にする必要
がある。
Nbは耐粒界腐食性に寄与する元素であり、粒
界腐食の原因になる有害Ｃを固定するには100×
（％Ｃ−0.005）％以上の添加が必要である。しか
し、Nbをあまり多量に添加すると熱間加工性が
劣化するので、Nbは4.0％以下にする必要があ
る。
Ｎは本発明合金においては不可欠の元素であ
り、機械的強度、耐粒界腐食性及び耐粒界応力腐
食割れ性の向上に有効である。Ｎは0.01％より少
ないと機械的強度、特に0.2％耐力が劣化し、一
方、0.05％より多いと第７図に示すようにＮの固
溶限界量に近づきブローホールが生じやすくなる
ので、Ｎは0.01〜0.05％の範囲内にする必要があ
る。
ＣとＮの和が0.040％より少ないと第６図に示
したように0.2％耐力が25Kg／mm2に達しないの
で、ＣとＮの和は0.040％以上にする必要があ
る。
Tiは脱酸剤として熱間加工性の改善に有効な
元素であり、またブローホールの発生を抑止する
効果が大きく、かつ溶接高温熱影響部の耐食性を
向上させる元素であるが、１％より多いと上記諸
効果が期待されないので、Tiは１％以下にする
必要がある。
（発明の効果）
以上本発明のNi基合金は0.2％耐力は25Kg／mm2
以上であり、耐粒界腐食性並びに耐応力腐食割れ
性に優れ、さらに熱間加工性に優れる合金であ
り、化学工業並びにエネルギー産業、なかでも原
子力発電用機器として優れた諸特性を有する合金
である。[Table] According to Table 3, the mechanical properties of the invention alloys 1 and 2, that is, 0.2% proof stress (Kg/mm 2 ), are as follows: Inconel 600
It can be seen that both are larger than the 0.2% proof stress standard of 25Kg/mm 2 and also larger than that of Comparative Alloys 3 and 4. According to the intergranular corrosion test, the maximum corrosion degree d of the present invention alloys 1 and 2 is both very small and good, less than 500 μm/day, but the comparative alloys 3 and 4 are good.
All of them were extremely large, exceeding 1500 μm/day. In addition, high temperature water stress corrosion cracking test (CBB
According to the results of the test, both Inventive Alloys 1 and 2 were good with no cracks, but both Comparative Alloys 3 and 4 had cracks. (Function) Next, the function of each component composition will be explained in detail. Figure 2 shows the amount of Nb at 0%, 0.5%, 1.5%, respectively.
It is a diagram showing the influence of the amount of C contained on the maximum degree of intergranular corrosion d when the content is 2.3%, and the limit amount of C at which the maximum degree of corrosion d becomes 500 μm/day or less increases as the amount of Nb added increases. Figure 3 shows d500μm/day in Figure 2.
This is a diagram showing the correlation between the limit C amount and the Nb amount at that time, and the straight line shown in the diagram shows the relationship of %Nb / (%C - 0.005) = 100 when N is 0.01% or more. , in the shaded area on the left side of the straight line, that is, %Nb/(%C - 0.005) 100, d is 500 μm/day or less, and in the area on the right side of the straight line, that is, %Nb/(%C −0.005)＜100
It can be seen that d is larger than 500 μm/day in the region. In the same figure, when C is larger than 0.045%, how to reduce d to 500 μm/day or less
It is necessary to contain more than 4% Nb,
When such a large amount of Nb is contained, hot workability deteriorates and productivity decreases. FIG. 4 is a diagram showing the experimental results of the effect of N and Ti addition on the degree of knife line attack erosion in the weld zone and heat affected zone, where the horizontal axis represents the distance from the bead and the vertical axis represents the degree of erosion. The curve shows the alloy containing 1.6% Nb, and the curve shows the alloy containing 1.6% Nb.
The curve shows alloy 1 of the present invention containing 0.029% N, and alloy 2 of the present invention containing 0.26% Ti in addition to the above amounts of Nb and N. In any case, there is almost no erosion at long distances from the bead, but at short distances there is almost no erosion.
The alloy containing only Nb has the highest degree of erosion, but
Addition of 0.029% N reduces the degree of erosion. Further, the degree of erosion is further reduced by adding 0.028% N and 0.26% Ti, and the knife line attack resistance is improved by adding N and Ti. Figure 5 is based on Inconel 600 alloy, with N
FIG. 2 is a diagram showing the relationship between heating temperature and aperture for alloys A to C containing 0.03% and varying the contents of several other elements. In the same figure, alloy A
is a comparative alloy containing 0.005% S, alloy B is
Alloy C, an alloy of the present invention containing 0.0004% S and 2.5% Nb, is a comparative alloy containing 0.004% S and 2.5% Nb. According to the figure, like the alloy B of the present invention, it has excellent hot workability due to extremely low S (S0.0010 or less), and
It exhibits almost 100% reduction even at high temperatures of °C. 1100 again
Looking at the aperture near °C, the alloy B of the present invention is compared to the comparative alloy A.
It can be seen that it is far superior to C and C. Figure 6 shows the sum of C and N in the alloy and the 0.2% proof stress σ0.2
It is a diagram showing the relationship between C and N, and the hardness and yield strength are
The larger the sum of
It can be seen from the figure that in order to satisfy the 0.2% proof stress standard of 600 of 25 kg/mm 2 or more, the sum of C and N must be 0.04% or more. Next, the reason for limiting the composition of the alloy of the present invention will be explained. If the C content is more than 0.045%, the Nb content must be increased to prevent deterioration of the corrosion resistance of the welded part, which will deteriorate hot workability.
C must be kept at 0.045% or less, and in terms of hot workability, the best results are obtained when it is 0.030% or less. If Si exceeds 0.5%, intergranular corrosion resistance deteriorates, so Si must be kept at 0.5% or less. If Mn exceeds 1.0%, intergranular corrosion resistance deteriorates, so Mn needs to be 1.0% or less. P is an element that is unavoidably mixed in as little as possible; however, if it is more than 0.030%, intergranular corrosion resistance and weldability deteriorate, so P must be kept at 0.030% or less. Like P, S is an element that is unavoidably mixed, and the smaller the amount, the better. If the amount exceeds 0.0010%, the hot workability deteriorates significantly, so the S content must be kept at 0.0010% or less. Cr is an essential element for exhibiting corrosion resistance, and if it is less than 14%, corrosion resistance will deteriorate, while if it is more than 17%, high temperature strength will increase and manufacturability will decrease, so Cr is 14 to 17%. Must be within the range of %. Fe is dissolved in the base material and has the effect of suppressing the precipitation of intermetallic compounds, and if it is less than 6%, the effect will be reduced, and if it exceeds 10%, corrosion resistance and mechanical strength will deteriorate, so Fe should be 6 to 10%. Must be within the range. Nb is an element that contributes to intergranular corrosion resistance, and in order to fix harmful C that causes intergranular corrosion,
It is necessary to add more than (%C-0.005)%. However, if too much Nb is added, hot workability deteriorates, so Nb needs to be 4.0% or less. N is an essential element in the alloy of the present invention, and is effective in improving mechanical strength, intergranular corrosion resistance, and intergranular stress corrosion cracking resistance. If N is less than 0.01%, the mechanical strength, especially 0.2% yield strength, will deteriorate, while if it is more than 0.05%, it will approach the solid solubility limit of N and blowholes will easily occur. must be within the range of 0.01-0.05%. If the sum of C and N is less than 0.040%, the 0.2% yield strength will not reach 25 kg/mm 2 as shown in Figure 6, so the sum of C and N must be 0.040% or more. Ti is an element effective in improving hot workability as a deoxidizing agent, and is also highly effective in suppressing the occurrence of blowholes, and is an element that improves the corrosion resistance of the weld high temperature heat affected zone. If it is too large, the above-mentioned effects cannot be expected, so it is necessary to keep Ti at 1% or less. (Effect of the invention) The Ni-based alloy of the present invention has a 0.2% yield strength of 25Kg/mm 2
As described above, it is an alloy that has excellent intergranular corrosion resistance and stress corrosion cracking resistance, as well as excellent hot workability, and has excellent properties for use in the chemical industry and energy industry, especially as equipment for nuclear power generation. be.
第１図は腐食試験に供した溶接試験片の斜視
図、第２図は合金の種々のNb含有量の場合につ
いてＣ含有量と粒界最大侵食度ｄとの関係を示す
図、第３図は合金のＣとNbの含有量が最大侵食
度ｄに及ぼす関係を示す図、第４図は合金の溶接
ビードからの距離と侵食度との関係を示す図、第
５図は合金の加熱温度と絞りとの関係を示す図、
第６図は合金のＣとＮの含有量の和と0.2％耐力
σ0.2との関係を示す図、第７図はＮ固溶量に及
ぼすNi，Cr，Fe含有量依存性を示す図である。
Figure 1 is a perspective view of a welded specimen subjected to a corrosion test, Figure 2 is a diagram showing the relationship between C content and maximum grain boundary erosion degree d for various Nb contents of the alloy, Figure 3 Figure 4 shows the relationship between the C and Nb contents of the alloy and the maximum erosion degree d, Figure 4 shows the relationship between the distance from the weld bead of the alloy and the erosion degree, and Figure 5 shows the heating temperature of the alloy. A diagram showing the relationship between and aperture,
Figure 6 is a diagram showing the relationship between the sum of C and N contents of the alloy and 0.2% proof stress σ0.2, and Figure 7 is a diagram showing the dependence of Ni, Cr, and Fe contents on the amount of N solid solution. It is.
Claims (1)
下、Cr14〜17％、Fe6〜10％、P0.030％以下、
S0.0010％以下、N0.01〜0.05％、ＣとＮとの和
0.040％以上、Nb4％以下でかつ100×（％Ｃ−
0.005）％以上を含み、残部実質的にNiよりなる
耐粒界腐食性、耐応力腐食割れ性及び熱間加工性
に優れるNi基合金。 ２ C0.045％以下、Si0.5％以下、Mn1.0％以
下、Cr14〜17％、Fe6〜10％、P0.030％以下、
S0.0010％以下、N0.01〜0.05％、ＣとＮとの和
0.040％以上、Nb4％以下でかつ100×（％Ｃ−
0.005）％以上、Ti1％以下を含み、残部実質的に
Niよりなる耐粒界腐食性、耐応力腐食割れ性及
び熱間加工性に優れるNi基合金。[Claims] 1 C0.045% or less, Si 0.5% or less, Mn 1.0% or less, Cr14-17%, Fe6-10%, P0.030% or less,
S0.0010% or less, N0.01~0.05%, sum of C and N
0.040% or more, Nb4% or less, and 100×(%C-
A Ni-based alloy containing 0.005% or more, with the remainder substantially consisting of Ni, which has excellent intergranular corrosion resistance, stress corrosion cracking resistance, and hot workability. 2 C0.045% or less, Si0.5% or less, Mn1.0% or less, Cr14-17%, Fe6-10%, P0.030% or less,
S0.0010% or less, N0.01~0.05%, sum of C and N
0.040% or more, Nb4% or less, and 100×(%C-
0.005)% or more, including Ti1% or less, the remainder substantially
A Ni-based alloy made of Ni that has excellent intergranular corrosion resistance, stress corrosion cracking resistance, and hot workability.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16683382A JPS5956555A (en) | 1982-09-25 | 1982-09-25 | Ni alloy with superior intergranular corrosion resistance, stress corrosion cracking resistance and hot processability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16683382A JPS5956555A (en) | 1982-09-25 | 1982-09-25 | Ni alloy with superior intergranular corrosion resistance, stress corrosion cracking resistance and hot processability |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20272186A Division JPS6244546A (en) | 1986-08-30 | 1986-08-30 | Ni alloy having superior resistance to intergranular corrosion and stress corrosion cracking and superior hot workability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5956555A JPS5956555A (en) | 1984-04-02 |
| JPS6211059B2 true JPS6211059B2 (en) | 1987-03-10 |
Family
ID=15838497
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16683382A Granted JPS5956555A (en) | 1982-09-25 | 1982-09-25 | Ni alloy with superior intergranular corrosion resistance, stress corrosion cracking resistance and hot processability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5956555A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| FR2596066B1 (en) * | 1986-03-18 | 1994-04-08 | Electricite De France | AUSTENITIQUE NICKEL-CHROME-FER ALLOY |
| JP5550374B2 (en) * | 2010-02-05 | 2014-07-16 | Ｍｍｃスーパーアロイ株式会社 | Ni-base alloy and method for producing Ni-base alloy |
| CN114058903B (en) * | 2020-07-30 | 2022-06-14 | 宝武特种冶金有限公司 | Nickel-iron-based alloy large-caliber thick-wall pipe and manufacturing method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55125251A (en) * | 1979-03-19 | 1980-09-26 | Sumitomo Metal Ind Ltd | Cr-containing ni alloy with superior stress corrosion cracking resistance and manufacture thereof |
| JPS5738662A (en) * | 1980-08-19 | 1982-03-03 | Japan Electronic Control Syst Co Ltd | Two-cycle internal combustion engine |
-
1982
- 1982-09-25 JP JP16683382A patent/JPS5956555A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55125251A (en) * | 1979-03-19 | 1980-09-26 | Sumitomo Metal Ind Ltd | Cr-containing ni alloy with superior stress corrosion cracking resistance and manufacture thereof |
| JPS5738662A (en) * | 1980-08-19 | 1982-03-03 | Japan Electronic Control Syst Co Ltd | Two-cycle internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5956555A (en) | 1984-04-02 |
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