Research on Corrosion Fatigue Crack Growth of Marine Engineering Equipment Material E690 High-Strength Steel

2019 ◽  
Vol 11 (6) ◽  
pp. 862-865
Author(s):  
Heng Wang ◽  
Xiao Liu ◽  
Guang-Xian Ni ◽  
Jie Jiang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
High Strength Steel ◽  
High Strength ◽  
Engineering Equipment ◽  
Corrosion Fatigue Crack ◽  
Corrosion Fatigue Crack Growth ◽  
Marine Engineering

Corrosion-Fatigue Crack Growth Performance of Titanium Grade 29 Welds in Tapered Stress Joints

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Gabriel Rombado ◽  
David A. Baker ◽  
Lars M. Haldorsen ◽  
Pedro da Silva Craidy ◽  
Jim H. Feiger ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
High Strength ◽  
Potential Effect ◽  
Steel Catenary Riser ◽  
Corrosion Fatigue Crack ◽  
Corrosion Fatigue Crack Growth ◽  
Titanium Grade

Abstract Design of a steel catenary riser requires the use of connection hardware to decouple the large bending moments induced by the host floater at the hang-off location. Reliability of this connection hardware is essential, particularly in applications involving high pressure and high temperature fluids. One option for this connection hardware is the metallic tapered stress joint. Titanium (Ti) Grade 29 has been identified as an attractive material candidate for demanding stress joint applications due to its “high strength, low weight, superior fatigue performance and innate corrosion resistance”.2 Titanium stress joints for deepwater applications are typically not fabricated as a single piece due to titanium ingot volume limitations, thus making an intermediate girth weld necessary to satisfy length requirements. As with steel, the potential effect of hydrogen embrittlement induced by cathodic and galvanic potentials must be assessed to ensure long-term weld integrity. This paper describes testing from a joint industry project (JIP) conducted to qualify titanium stress joint (TSJ) welds for ultra-deepwater applications under harsh service and environmental conditions. Corrosion-fatigue crack growth rate (CFCGR) results for Ti Grade 29 flat welding-groove weld (1G/PA) gas tungsten arc welding (GTAW) specimens in seawater under cathodic potential and sour brine under galvanic potential are presented and compared to vendor recommended design curves.

The Effect of Cyclic Loading Frequency on Corrosion-Fatigue Crack Growth in High-Strength Riser Materials

2010 ◽  
Author(s):  
Stephen J. Hudak ◽  
James H. Feiger ◽  
Jason A. Patton
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Growth Rates ◽  
High Strength ◽  
Loading Frequency ◽  
Corrosion Fatigue Crack ◽  
Corrosion Fatigue Crack Growth ◽  
Crack Growth Rates

Corrosion-fatigue is a significant design consideration in deepwater floating production systems. Mechanical loading is accentuated due to the compliant nature of these structures, and sour service conditions can also occur either due to the nature of the crude production or due to seawater flooding of the reservoir to enhance production yield. New high-strength riser steels have recently been developed to meet the demands of deepwater development. The objective of this study was to characterize the corrosion-fatigue resistance of these materials in terms of crack growth rates as a function of applied stress intensity factor range (ΔK), as well as cyclic loading frequency. Experiments were performed on five different steels with yield strengths ranging from 848 to 1080 MPa. Two environments were considered: seawater with cathodic protection to simulate the environment outside of the riser, and a sour brine environment with low oxygen (< 10 ppb) to simulate the environment inside the riser. Not all steels were tested in the sour brine environment since not all were designed to operate in sour service. For both environments, higher strength steels were found to exhibit higher growth rates and lower saturation frequencies. Fatigue crack growth rates as a function of ΔK were also measured, and exhibited two different frequency responses. At high ΔK, the classical frequency response occurred: decreased frequency gave increased crack growth rates. At low ΔK, an inverse frequency effect was observed: deceased frequency gave decreased crack growth rates, as well as increased corrosion-fatigue crack growth thresholds. These differences are believed to be caused by different underlying processes controlling crack growth — specifically, material-environment reaction kinetics at high ΔK, and crack closure due to corrosion-product wedging at low ΔK. The practical significance of these results is discussed, including selection of frequencies for corrosion-fatigue crack growth testing, and applicability of results to structural integrity assessments.

scholarly journals Effects of Waveform and Cycle Period on Corrosion-Fatigue Crack Growth in Cathodically Protected High-Strength Steels

2014 ◽  
Vol 891-892 ◽  
pp. 211-216 ◽  
Author(s):  
Mark Knop ◽  
Nick Birbilis ◽  
Stan Lynch
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Growth Rates ◽  
High Strength Steels ◽  
High Strength ◽  
Corrosion Fatigue Crack ◽  
Corrosion Fatigue Crack Growth ◽  
Crack Growth Rates

The processes involved in corrosion fatigue in general are briefly outlined, followed by a brief review of recent studies on the effects of cycle frequency (rise times) and electrode potential on crack-growth rates at intermediate ΔK levels for cathodically protected high-strength steels. New studies concerning the effects of fall times and hold times at maximum and minimum loads on crack-growth rates (for Kmax values below the sustained-load SCC threshold) are presented and discussed. Fractographic observations and the data indicate that corrosion-fatigue crack-growth rates in aqueous environments depend on the concentration of hydrogen adsorbed at crack tips and at tips of nanovoids ahead of cracks. Potential-dependent electrochemical reaction rates, crack-tip strain rates, and hydrogen transport to nanovoids are therefore critical parameters. The observations are best explained by an adsorption-induced dislocation-emission (AIDE) mechanism of hydrogen embrittlement.

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