第3次クリープに着目した25Cr-20Niステンレス鋼の高温クリープ挙動解析

• 朴 仁徳

  横浜国立大学工学部生産工学科

• 増山 不二光

  三菱重工業株式会社長崎研究所

• 遠藤 孝雄

  横浜国立大学工学部生産工学科

書誌事項

タイトル別名

• Creep Behavior Analysis of 25Cr-20Ni Stainless Steels with a Special Reference to Tertiary Creep
• ダイ3ジ クリープ ニ チャクモク シタ 25Cr 20Ni ステンレス コウ ノ コウオン クリープ キョドウ カイセキ

抄録

For two kinds of 25Cr-20Ni stainless steels, A and B with and without a small amount of Nb and N, creep behavior has been studied in a stress and temperature range from 141 to 343 MPa and from 923 to 973 K with a special reference to tertiary creep. The average creep life of the A steel was about 100 times longer than that of the B steel. The logarithm of strain rate (\dotε) in a tertiary stage was well expressed by the following equation:<BR>ln\dotε=ln\dotε₀+Ω·ε,<BR>\oindentwhere \dotε₀ is the imaginary initial strain rate, ε is the true strain and Ω is the strain rate acceleration factor.<BR>The apparent activation energy for the initial creep rate was 330 kJ/mol in the A steel, while that of the B steel was 274 kJ/mol in a power law creep region and 478 kJ/mol in a region of power law breakdown (PLB). The activation energy for the B steel below PLB is close to the that for self-diffusion. When compensating for the temperature dependence of the Young’s modulus and the omega value, it was found that the apparent activation energy for the A steel was reduced to the activation energy for diffusion of chromium atom in a gamma steel. The stress exponent of the B steel was about 12 above PLB and 5.1 in a power law creep region. Notwithstanding that the creep condition for the A steel was in a power law creep region, its stress exponent was 8.3 larger than that of the B steel corresponding to the same creep conditions. This was ascribed to the presence of fine precipitates in the A steel. When stress was increased abruptly during deformation, instantaneous plastic strain was observed in the B steel but not in the A steel. These results as well as TEM observation suggest that dislocations in the A steel drag the atmosphere composed of Cr-N clusters behind them.

収録刊行物

• 日本金属学会誌

  日本金属学会誌 64 (12), 1181-1188, 2000

  公益社団法人 日本金属学会

キーワード

• stainless steel
• nitrogen
• high temperature
• creep
• I-S pair
• solid solution hardening

詳細情報

• CRID: 1390282681467668480
• NII論文ID: 130007341542
• NII論文ID: 10005344051
• NII書誌ID: AN00187860
• DOI: 10.2320/jinstmet1952.64.12_1181
• ISSN: 18806880
• ISSN: 24337501
• ISSN: 00214876
• NDL書誌ID: 5625795
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I5625795
• Web Site: https://www.jstage.jst.go.jp/article/jinstmet1952/64/12/64_12_1181/_pdf
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