Evaluation of long-term creep rupture life of strength enhanced high Cr ferritic steel on the basis of its temperature dependence

K. Maruyama, Junya Nakamura, Kyosuke Yoshimi

研究成果: Paper査読

3 被引用数 (Scopus)

抄録

Conventional time-temperature-parameter (TTP) methods often overestimate long-term creep rupture life of creep strength enhanced high Cr ferritic steels. The cause of the overestimation is studied on the basis of creep rupture data analysis on Gr.91, 92 and 122 steels. There are four regions with different values of stress exponent n for creep rupture life commonly in stress-rupture data of the three ferritic steels. Activation energies Q for rupture life in the regions take at least three different values. The values of n and Q decrease in a longer-term region. The decrease in Q value is the cause of the overestimation of long-term rupture life predicted by the conventional TTP methods neglecting the change in Q value. Therefore, before applying a TTP method creep rupture data should be divided into several data sets so that Q value is unique in each divided data set. When this multi-region analysis is adopted, all the data points of the steels can be described accurately, and their long-term creep life can be evaluated correctly. Substantial heat-to-heat and grade-to-grade variation in their creep strength is suggested under recent service conditions of USC power boilers.

本文言語English
ページ732-743
ページ数12
出版ステータスPublished - 2014 1月 1
イベント7th International Conference on Advances in Materials Technology for Fossil Power Plants - Waikoloa, HI, United States
継続期間: 2013 10月 222013 10月 25

Other

Other7th International Conference on Advances in Materials Technology for Fossil Power Plants
国/地域United States
CityWaikoloa, HI
Period13/10/2213/10/25

ASJC Scopus subject areas

  • 燃料技術
  • 再生可能エネルギー、持続可能性、環境

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