Nanoindentation Characterization of Creep-fatigue Interaction on Local Creep Behavior of P92 Steel Welded Joint

Chinese Journal of Mechanical Engineering

Yi Ma¹  Zhouxin Pan²  Yuebing Li²  Zengliang Gao³  Yuxuan Song⁴  Taihua Zhang⁵ 

[1] Institute of Micro/Nano-Mechanical Testing Technology & Application, College of Mechanical Engineering, Zhejiang University of Technology, 310014, Hangzhou, China;Institute of Process Equipment and Control Engineering, College of Mechanical Engineering, Zhejiang University of Technology, 310014, Hangzhou, China;Institute of Process Equipment and Control Engineering, College of Mechanical Engineering, Zhejiang University of Technology, 310014, Hangzhou, China;Engineering Research Center of Process Equipment and Re-manufacturing, Ministry of Education, 310014, Hangzhou, China;Institute of Process Equipment and Control Engineering, College of Mechanical Engineering, Zhejiang University of Technology, 310014, Hangzhou, China;Institute of Micro/Nano-Mechanical Testing Technology & Application, College of Mechanical Engineering, Zhejiang University of Technology, 310014, Hangzhou, China;Institute of Solid Mechanics, Beihang University, 100000, Beijing, China;

关键词: P92 steel;    Welded joint;    Creep–fatigue interaction;    Nanoindentation;    Creep behavior;   

DOI  :  10.1186/s10033-021-00661-5

来源: Springer

【 摘 要 】

In modern fossil and nuclear power plants, the components are subjected to creep, fatigue, and creep-fatigue (CF) due to frequent start-up and shut-down operations at high temperatures. The CF interaction on the in-service P92 steel welded joint was investigated by strain-controlled CF tests with different dwell times of 30, 120, 300, 600 and 900 s at 650 °C. Based on the observations of the fracture surface by scanning electron microscope (SEM), the characteristic microstructure of fatigue-induced damage was found for the CF specimens with short dwell times (30 and 120 s). The hardness, elastic modulus and creep deformation near the fracture edges of four typical CF specimens with 30, 120, 600 and 900 s dwell times were measured by nanoindentation. Compared to specimens with post-weld heat treatment (PWHT), lower hardness and creep strength were found for all CF specimens. In addition, significant reductions in hardness, elastic modulus, and creep strength were measured near the fracture edges for the CF specimens with short dwell times compared to the PWHT specimens. Compared to PWHT specimens (0.007), the increased strain rate sensitivities (SRS) of 0.010 to 0.17 were estimated from secondary creep. The increased values of SRS indicate that the room temperature creeps behavior is strongly affected by the decrease in dislocation density after the CF tests.

【 授权许可】

CC BY