Computational Modeling of Hydrogen-Assisted Fatigue Crack Growth in Pipeline Steels

2017 ◽  
pp. 597-604
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Computational Modeling ◽  
Crack Growth ◽  
Pipeline Steels

The Effect of Microstructure on the Hydrogen-Assisted Fatigue of Pipeline Steels

2013 ◽  
Author(s):  
Andrew J. Slifka ◽  
Elizabeth S. Drexler ◽  
Douglas G. Stalheim ◽  
Robert L. Amaro ◽  
Damian S. Lauria ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Pressures ◽  
Load Ratio ◽  
Fatigue Tests ◽  
Hydrogen Gas ◽  
The Other ◽  
Stress Intensity Factor Range ◽  
Pipeline Steels

Tests on the fatigue crack growth rate were conducted on four pipeline steels, two of grade API 5L-X52 and two API 5L-X70. One X52 material was manufactured in the mid-1960s and the other was manufactured in 2011. The two X70 materials had a similar vintage and chemistry, but the microstructure differs. The fatigue tests were performed in 5.5 and 34 MPa pressurized hydrogen gas, at 1 Hz and (load ratio) R = 0.5. At high pressures of hydrogen and high values of the stress intensity factor range (ΔK) there is no difference in the fatigue crack growth rates (da/dN), regardless of strength or microstructure. At low values of ΔK, however, significant differences in the da/dN are observed. The older X52 material has a ferrite-pearlite microstructure; whereas, the modern X52 has a mixture of polygonal and acicular ferrites. The X70 materials are both predominantly polygonal ferrite, but one has small amounts (∼5%) of upper bainite, and the other has small amounts of pearlite (<2%) and acicular ferrite (∼5%). We discuss the fatigue test results with respect to the different microstructures, with particular emphasis on the low ΔK regime.

Effect of hydrogen and low temperature on fatigue crack growth of pipeline steels

2013 ◽  
Vol 103 ◽  
pp. 10-25 ◽  
Author(s):  
P. Fassina ◽  
M.F. Brunella ◽  
L. Lazzari ◽  
G. Re ◽  
L. Vergani ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Low Temperature ◽  
Crack Growth ◽  
Pipeline Steels

scholarly journals Effects of microstructure banding on hydrogen assisted fatigue crack growth in X65 pipeline steels

2016 ◽  
Vol 82 ◽  
pp. 497-504 ◽  
Author(s):  
Joseph A. Ronevich ◽  
Brian P. Somerday ◽  
Chris W. San Marchi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pipeline Steels

Summary of an ASME/DOT Project on Measurements of Fatigue Crack Growth Rate of Pipeline Steels

2014 ◽  
Author(s):  
Andrew J. Slifka ◽  
Elizabeth S. Drexler ◽  
Robert L. Amaro ◽  
Damian S. Lauria ◽  
Louis E. Hayden ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Yield Strength ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Hydrogen Gas ◽  
Lessons Learned ◽  
Pipeline Steels

The National Institute of Standards and Technology has been testing pipeline steels for about 3 years to determine the fatigue crack growth rate in pressurized hydrogen gas; the project was sponsored by the Department of Transportation, and was conducted in close collaboration with ASME B31.12 Committee on Hydrogen Piping and Pipelines. Four steels were selected, two X52 and two X70 alloys. Other variables included hydrogen gas pressures of 5.5 MPa and 34 MPa, a load ratio, R, of 0.5, and cyclic loading frequencies of 1 Hz, 0.1 Hz, and a few tests at 0.01 Hz. Of particular interest to ASME and DOT was whether the X70 materials would exhibit higher fatigue crack growth rates than the X52 materials. API steels are designated based on yield strength and monotonic tensile tests have historically shown that loss of ductility correlates with increase in yield strength. The X70 materials performed on par with the X52 materials in fatigue. The test matrix, the overall set of data, implications for the future, and lessons learned during the 3-year extensive test program will be discussed.

Fatigue Crack Growth Rates in Six Pipeline Steels

2006 ◽  
Author(s):  
A. Bussiba ◽  
Ph. P. Darcis ◽  
J. D. McColskey ◽  
C. N. McCowan ◽  
G. Kohn ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Internal Surface ◽  
Type Specimen ◽  
Stable Crack Growth ◽  
Pipeline Steels ◽  
Growth Regime ◽  
Failure Assessment ◽  
Fatigue Crack Growth Test

This study presents fatigue data for six different pipeline steels, with strengths ranging from Grade B to X100. A fatigue crack growth test for full thickness pipeline samples was developed using a Middle Tension (MT) type specimen. The six steels showed similar fatigue crack growth rate (da/dN) behavior. There were only minor differences among the steels for the threshold values and most of the stable crack growth regime. Larger differences were observed in the final stages of crack growth and fatigue failure. The effect of compressive residual stresses at the outer surface of the pipeline was also examined. A Failure Assessment Diagram technique was used to evaluate the potential failures modes of the six pipeline steels, containing, as an example, an internal surface, semi-elliptic, axially oriented flaw. Mixed-mode failure was predicted for all of the steels.

scholarly journals Near- threshold Fatigue Crack Growth Behavior and Crack Closure of Natural Gas Pipeline Steels

2011 ◽  
Vol 10 ◽  
pp. 813-820 ◽  
Author(s):  
Young-Pyo Kim ◽  
Cheol-Man Kim ◽  
Woo-Sik Kim ◽  
Kyo-Soo Song ◽  
Kwang-Seon Shin
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Natural Gas ◽  
Crack Growth ◽  
Crack Closure ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Pipeline Steels ◽  
Natural Gas Pipeline

Effects of Specimen Geometry on Fatigue-Crack Growth Rates in Pipeline Steels

2008 ◽  
Author(s):  
J. M. Treinen ◽  
Ph. P. Darcis ◽  
J. D. McColskey ◽  
R. Smith ◽  
J. Merritt
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Specimen Geometry ◽  
Tension Specimen ◽  
Pipeline Steels ◽  
Crack Growth Rates

The effects of specimen geometry on the fatigue crack growth rates (FCGR) in API X65 and X100 pipeline steels were explored by use of the middle tension and compact tension specimen geometries. It was found that the specimen type has little influence on the stage II linear fatigue crack growth region for these steels. Furthermore, the FCGR behavior in the longitudinal and transverse directions was found to be nearly identical for both steels. Also of interest was a comparison of the FCGR results to the BS 7910 design curves, which showed a discrepancy between the results and the standard only at low delta K levels. A finite element analysis of the compliance relationships used to predict the crack lengths during testing of both specimen types revealed that the expression for both the middle tension specimen and the compact tension specimen were found to be valid. Although the curved geometry of the middle tension specimen caused slightly different compliance results, these differences did not appear to affect the FCGR results.

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