The role of minor cyclic loading in crack growth of pipeline steel exposed to near-neutral pH environment
This study was initiated to understand the role of minor cyclic loading, a typical scenario of pressure fluctuations during the operation of high-pressure gas transmission pipelines, in overall crack growth of X60 pipeline steel in near-neutral pH solution.A loading waveform consisting of small constant amplitude cycles with a high R ratio (minimum stress/maximum stress) of 0.9 and periodic single underloading cycle with R ratio of 0.5 was designed and applied to compact tension specimens to induce crack growth in air and in nearneutral pH environments, respectively.To further confirm the role of minor cyclic loading, crack growth under a loading waveform consisting of static hold replacing the minor loading cycles and the periodic underload cycles was also determined.It has been found that the minor cyclic loading could enhance the crack growth in the presence of underloads by a factor of 4.2 and 2.1, respectively, in air and in near neutral pH environment.Static holding could actually reduce the crack growth rate of underloading cycles by a factor of 0.35 in near-neutral pH solution.The possible mechanisms on the role of minor cyclic loading in overall crack growth were also discussed in the paper.
underloads pipeline steel corrosion fatigue variable amplitude cyclic loading near-neutral pH SCC
Mengshan Yu Weixing Chen Richard Kania Greg Van Boven Robert Worthingham
Department of Chemical and Materials Engineering,University of Alberta,Edmonton,Canada T6G 2G6 TransCanada Pipelines Limited,Calgary,Alberta,Canada T2P 5H1 Spectra Energy Transmission,Vancouver,British Columbia,Canada V6E 3P3
国内会议
2013中国国际管道会议暨第一届中国管道与储罐腐蚀与防护学术交流会
廊坊
英文
331-339
2013-09-01（万方平台首次上网日期，不代表论文的发表时间）