Open AccessInfluence of thermal ageing on creep rupture mechanism and creep life of P92 ferritic steel
Author(s) -
Hyeok-Gu Kang,
Jizhong Shen,
Shanjun Zhang,
Hongguang Han,
Fuyong Hu,
Biao He,
Qingquan Zhao,
Guoqing Xiao
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/abaf3f
Subject(s) - creep , materials science , microstructure , ageing , dislocation , scanning electron microscope , laves phase , composite material , metallurgy , thermal , grain boundary , intermetallic , thermodynamics , alloy , genetics , physics , biology
In order to analyze the effect of thermal ageing on creep rupture mechanism and establish a method for predicting the creep rupture life of P92 heat-resistant steel under thermal ageing, creep tests were performed on P92 steel specimens, aged at 650 °C for different times under different applied stresses. Optical microscopy and scanning electron microscopy were utilized to observe the microstructure after thermal ageing and creep rupture. Voids and cracks were distributed in the grains of P92 steel before thermal ageing, whereas the voids were clearly distributed around M 23 C 6 precipitates and Laves phase along sub-grain boundaries after thermal ageing. The creep damage tolerance factor of the unaged and short-time aged samples ranged from 2.5 to 5, and the creep rupture was caused by dislocation movement. After high-temperature thermal ageing for 3000 h, the damage tolerance factor increased to > 5 and creep rupture was caused by precipitate coarsening. A theoretical method was established to predict the creep rupture life of heat-resistant P92 steel under thermal ageing, providing consistent results with the American Society of Mechanical Engineers (ASME) long-term test and trend.