Evaluation of the effect of various prior creep-fatigue interaction damages on subsequent tensile and creep properties of 9%Cr steel

Wei Zhang, Xiaowei Wang, Haofeng Chen, Tianyu Zhang, Jianming Gong

Research output: Contribution to journalArticle

9 Citations (Scopus)
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Abstract

The degradation of tensile and creep properties is inevitable during high temperature service operation. Hence this work aims to evaluate the effect of prior creep-fatigue interaction damages on remnant tensile and creep properties of 9%Cr steel. Prior creep-fatigue tests interrupted at different lifetime fractions and different tensile hold times are performed at 650 °C. Afterwards, subsequent tensile and creep tests are conducted at the same temperature. Results reveal that high lifetime fraction of prior creep-fatigue loading leads to obvious reduction of remnant tensile strength and creep resistance. However, the increase in tensile hold time hardly alters the remnant properties. Microstructure and fracture surface observations indicate that the deterioration of remnant tensile strength is mainly ascribed to the decline of dislocation density occurred during prior creep-fatigue process, whereas the growth of martensite lath plays the dominated role in the reduction of remnant creep resistance. Moreover, surface crack also accelerates the decline of creep resistance at high lifetime fraction. To quantify the prior creep-fatigue interaction damage, a fatigue damage indicator is proposed. Determined relationships between remnant tensile, creep properties and defined fatigue damage are obtained.
Original languageEnglish
Pages (from-to)440-453
Number of pages14
JournalInternational Journal of Fatigue
Volume125
Early online date13 Apr 2019
DOIs
Publication statusPublished - 1 Aug 2019

Keywords

  • prior creep-fatigue loading
  • remnant tensile and creep properties
  • microstructure
  • damage indicator

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