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Title: Fatigue-Crack-Growth Behavior of Two Pipeline Steels

This paper focuses on studying the fatigue-crack-growth behavior of two types of pipeline steels, and investigating their microstructural differences, which could influence the fatigue behavior. For fatigue experiments, compact-tension (CT) specimens are employed. These two kinds of base pipeline steels are Alloy B [Fe-0.05C-1.52Mn-0.12Si-0.092Nb, weight percent (wt.%)] and Alloy C [(Fe- 0.04C-1.61Mn-0.14Si-0.096Nb, wt.%)]. They have been tested at various frequencies (10 Hz, 1 Hz, and 0.1 Hz) and different R ratios (0.1 and 0.5, R = P min./P max. where P min. is the minimum applied load, and P max. is the maximum applied load) in air. The effects of frequencies and R ratios on crackpropagation behavior are compared. The microstructures of fracture surfaces are investigated, using both scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM). It is concluded that higher R ratios lead to faster crack-growth rates, while frequency does not have much influence on the fatigue-crack-growth rates. Moreover, Alloy B (Fe-0.05C-1.52Mn-0.12Si-0.092Nb, wt.%) tends to have better fatigue resistance than Alloy C (Fe-0.04C-1.61Mn-0.14Si-0.096Nb, wt.%) under various test conditions in air.
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. DGS Metallurgical Solutions, Inc., Vancouver, WA (United States)
  4. Yuan Ze Univ., Chung-Li (Taiwan). Dept. of Chemical Engineering and Materials Science
  5. National Chiao Tung Univ., Hsinchu (Taiwan). Dept. of Materials Science and Engineering; Industrial Technology Research Inst., Hsinchu (Taiwan). Material and Chemical Research Lab.
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357; USDOTDTPH56-10-T-000001; FE0008855; FE0024054; FE0011194
Accepted Manuscript
Journal Name:
Advanced Engineering Materials
Additional Journal Information:
Journal Volume: 18; Journal Issue: 12; Journal ID: ISSN 1438-1656
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE); Work for Others (WFO); Ministry of Science and Technology (MOST); US Department of Transportation; National Science Foundation (NSF)
Country of Publication:
United States
36 MATERIALS SCIENCE; Pipeline steels; compact-tension (CT) specimens; fatigue-crack-growth rates
OSTI Identifier: