TY - JOUR
T1 - An interpretation of creep rupture properties of grade 91 steel service- exposed for 100,000 hours at 600 °C
AU - Maruyama, K.
AU - Yaguchi, M.
AU - Minami, Y.
AU - Tamura, K.
AU - Yoshimi, K.
N1 - Funding Information:
Discussion with Prof. I. Nonaka, Tohoku University and Dr. I. Kajigaya, Sumitomo Corporation provided useful suggestions to this paper. One of the authors (KM) deeply acknowledges Prof. Nonaka and Dr. Kajigaya for their valuable suggestions.
Publisher Copyright:
© 2021 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2022
Y1 - 2022
N2 - Creep rupture data of grade 91 steel used as hot reheat pipes have been reported recently. The data are investigated by comparison with the creep rupture database of the steel in normalised and tempered (NT) states. Four regions H, M, L and G with different values of stress exponent appear in creep of grade 91 steel. The pipes were used in long-term region G (around 600 °C for 100,000 hours) in fossil-fired power plants. Medium- and low-stress regions M and L are confirmed to exist in the service-exposed states. Stress exponents in the two regions are kept unchanged in all the pipes, but the service exposure reduces their remaining creep rupture lives. The reduction is significant in the pipes made by cold bending. The service exposure retards the appearance of long-term region G. Causes of these findings are discussed in this paper.
AB - Creep rupture data of grade 91 steel used as hot reheat pipes have been reported recently. The data are investigated by comparison with the creep rupture database of the steel in normalised and tempered (NT) states. Four regions H, M, L and G with different values of stress exponent appear in creep of grade 91 steel. The pipes were used in long-term region G (around 600 °C for 100,000 hours) in fossil-fired power plants. Medium- and low-stress regions M and L are confirmed to exist in the service-exposed states. Stress exponents in the two regions are kept unchanged in all the pipes, but the service exposure reduces their remaining creep rupture lives. The reduction is significant in the pipes made by cold bending. The service exposure retards the appearance of long-term region G. Causes of these findings are discussed in this paper.
KW - creep damage
KW - Grade 91 steel
KW - linear life-fraction rule
KW - residual life assessment
KW - service exposure
KW - steam pipe
KW - strain-induced subgrain coarsening
KW - USC steam power plant
UR - http://www.scopus.com/inward/record.url?scp=85119976605&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85119976605&partnerID=8YFLogxK
U2 - 10.1080/09603409.2021.2007004
DO - 10.1080/09603409.2021.2007004
M3 - Article
AN - SCOPUS:85119976605
SN - 0960-3409
VL - 39
SP - 44
EP - 54
JO - Materials at High Temperatures
JF - Materials at High Temperatures
IS - 1
ER -