Fatigue Crack Growth at Electrical Resistance Welding Seam of API 5L X-70 Steel Line Pipe at Varied Orientations

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Craig Taylor ◽  
Sreekanta Das ◽  
Laurie Collins ◽  
Muhammad Rashid
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Base Metal ◽  
Electrical Resistance ◽  
Weld Seam ◽  
Full Scale ◽  
Resistance Welding ◽  
Line Pipe ◽  
Full Scale Testing

Very few studies have been conducted concerning fatigue in steel line pipe and fewer using full-scale testing. Further, at the time of this study, no research on full-scale testing was available in open literature regarding fatigue behavior of line pipe with longitudinal cracks, despite being considered more critical than the line pipe with cracks oriented in the circumferential direction. In the current research work, fatigue crack growth was investigated in NPS 20, API 5L X-70 grade, electrical resistance welding (ERW) straight-seam steel line pipes in the base metal and at the weld seam for various orientations. It was found that there was no significant difference between fatigue crack growth in the base metal and at the weld seam for the tested stress ratio. Increasing the angle of inclination of the crack with respect to the weld line was found to decrease the rate of fatigue crack growth due to a decrease in the mode I stress component. Finally, it was observed that despite the difference in fatigue crack growth rates, the crack aspect ratios were nearly identical for all cracks at the same crack depth.

Full Scale Test Validation of Fatigue Crack Growth Rate of Flaws in Erw Pipe

2021 ◽  
Author(s):  
Aaron Dinovitzer ◽  
Sanjay Tiku ◽  
Morvarid Ghovanlou ◽  
Mark Piazza ◽  
Thomas Jones
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Full Scale ◽  
Test Validation ◽  
Full Scale Test ◽  
Scale Test

Fatigue Crack Growth Behavior of Friction Stir Welding of 6063-T5 Aluminum Alloys

2010 ◽  
Vol 146-147 ◽  
pp. 1498-1501
Author(s):  
Supachai Surapunt
Keyword(s):  
Fatigue Crack ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Base Metal ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Friction Stir

The microstructure and fatigue crack growth behavior of friction stir welding of 6063-T5 aluminum alloys were investigated. For this propose, fatigue crack growth curves were determined in four different locations of notch, which are base metal, middle of welded zone (parallel to weld line), near interface and interface (shoulder limits). The crack initiation and crack propagation of the base metal specimens presented slower than those of stir welded specimens. The microstructure observations show that the grain sizes in stir welded zone are finer than that in the unaffected base material and in the heat affected zone.

scholarly journals Investigation of Fatigue Crack Growth in Full-Scale Railway Axles Subjected to Service Load Spectra: Experiments and Predictive Models

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1427
Author(s):  
Amir Pourheidar ◽  
Luca Patriarca ◽  
Stefano Beretta ◽  
Daniele Regazzi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Behavior ◽  
Full Scale ◽  
Experimental Results ◽  
Residual Lifetime ◽  
Crack Growth Behavior ◽  
Load Spectra ◽  
Life Predictions

In this paper, a series of experimental investigations was performed on full-scale railway axles to analyze the fatigue crack growth behavior of EA4T steel under load spectrum derived from real operating conditions. The experimental results were compared to life predictions carried out adopting two models: (i) the conventional Nasgro equation and (ii) the cyclic R-curve concept implemented in the Modified Nasgro equation for describing the crack growth behavior of an arbitrary crack length. The results show that the life predictions performed by means of the Modified Nasgro equation coincide well with the experimental results with an underestimation of the residual lifetime less than 32%, while the traditional Nasgro equation leads to significant overestimation (≈120%) of the residual lifetime for load spectra close to the in service scenario.

Fatigue-Crack Growth in an X-65 Line-Pipe Steel at Low Cyclic Frequencies in Aqueous Environments

1975 ◽  
Vol 97 (4) ◽  
pp. 298-304 ◽  
Author(s):  
O. Vosikovsky
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Pipe Steel ◽  
Functional Dependence ◽  
Distinct Pattern ◽  
Cathodic Potential ◽  
Line Pipe ◽  
Line Pipe Steel

The effects of salt and distilled water environments on fatigue-crack growth rates have been evaluated for an X-65 line-pipe steel. Tests were conducted over a frequency range between 10 and 0.01 Hz, under conditions of cathodic potential and free corrosion. A distinct pattern in the functional dependence of growth rates on ΔK and frequency has been found. Maximum environmental enhancement of growth rates was 50 times that of air at a cathodic potential of −1.04V, and 10 times that of air at a free-corrosion potential of −0.68V. In each case it occurred at the lowest frequency and at relatively high values of ΔK. Hydrogen embrittlement and the two-stage cracking process are examined as the main mechanisms of growth acceleration.

Effect of Sour Acidizing Treatments on the Fatigue Crack Growth and Fracture Toughness Behavior of C-Mn Line Pipe Steels

2016 ◽  
Author(s):  
Weiwei Yu ◽  
Jonathan Bowman ◽  
Apurva Batra ◽  
Ramgopal Thodla ◽  
Colum Holtam ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Compact Tension ◽  
Pipe Steels ◽  
Production Environment ◽  
Line Pipe ◽  
Fatigue And Fracture ◽  
Girth Welds

Acidizing treatments are typically performed intermittently during the life of a well. However, more recently there has been a desire to perform an increased number of acidizing treatments in order to improve production. The acidizing treatments typically involve highly corrosive acids, such as hydrofluoric (HF), hydrochloric (HCl) and acetic acid, which are known to cause significant corrosion. In the presence of hydrogen sulfide (H2S), these acidizing treatments could cause environmentally assisted fatigue and fracture (i.e. increased fatigue crack growth rates and reduced fracture toughness). A test program is underway to evaluate and quantify the effect of sour acidizing treatments on the fatigue and fracture behavior of welded C-Mn line pipe steels. This paper describes the preliminary findings from fatigue crack growth rate (FCGR) and fracture toughness (FT) tests on as-welded (i.e. unstrained) pipe. All tests were conducted at room temperature (RT) using compact tension (CT) specimens notched in the parent pipe (PP). Frequency scan FCGR tests were performed in the following sour acid conditions: simulated production environment (PE), spent acid without inhibitor and spent acid with residual corrosion inhibitor. The PE consisted of a simulated brine with pH = 4.5 and partial pressure of H2S (pH2S) = 0.21psia. FCGRs in the sour PE were of the order of 20 times faster than in air. The pH2S was the same for the tests in spent acid environments, but the pH was lower (approximately 3.5). As would be expected, the FCGRs were much higher in the low pH environment. The highest FCGRs were observed in the inhibited sour spent acid environment and were up to 100 times faster than in air. Sour FT tests were also conducted in the PE and in spent acid with and without inhibitor. In all cases, the measured FT values were significantly lower than in air. The test in PE exhibited higher FT than in the sour acidizing environment. The lowest FT values were observed in spent acid with inhibitor. Future work will investigate the effect of reeling on the fatigue and FT performance of pipe girth welds in sour acidizing environments.

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