Stress Corrosion Cracking in a Unidirectional E-Glass/Polyester Composite Subjected to Static and Cyclic Loading Conditions

2003 ◽  
Vol 25 (4) ◽  
pp. 11919 ◽  
Author(s):  
EA Armanios ◽  
RB Bucinell ◽  
DW Wilson ◽  
D Armentrout ◽  
M Gentz ◽  
...  
Author(s):  
B. Y. Fang ◽  
J. Q. Wang ◽  
E.-H. Han ◽  
Z. Y. Zhu ◽  
W. Ke

Stress corrosion cracking behavior of X70 pipeline steel was studied using slow strain rate tests (SSRT) and cyclic loading at high R and low frequency in a nearneutral pH soil solution saturated with 5% CO2+95% N2. The soil was from Xinjiang Uygur Autonomous Region where the Chinese West-East natural gas transmission pipeline started. Electrochemical tests including a potentiodynamic polarization technique and electrochemical impedance spectrum (EIS) were also conducted in order to analyze the effect of the concentration of bicarbonate, bubbled gas and the addition of chloride ion on the polarization behaviors. The results of SSRT showed that transgranular stress corrosion cracking (TGSCC) occurred in Xinjiang soil solution. Crack initiation was associated with pitting, inclusion and streamline of rolling. The susceptibility to SCC increased with the decrease of the applied electrochemical potential and strain rate. Cyclic loading tests with smooth specimens showed that some cracks initiated after certain cycles and cracking mode was transgranular. Under the cyclic loading of high R and low frequency, the crack propagation rate (CPR) of precracked specimens did not increase at some region of stress intensity factor range (ΔK), which showed that the crack propagation process was dominated by SCC. The results of the electrochemical tests showed that the polarization behaviors were influenced greatly by the concentration of bicarbonate, bubbled gas and the addition of chloride ion. Low concentration of chloride ion in bicarbonate could cause the elimination of passivity and SCC behavior to that in near-neutral pH soil solution.


Author(s):  
Brett Conrad ◽  
Weixing Chen ◽  
Reg Eadie ◽  
Richard Kania ◽  
Greg Van Boven ◽  
...  

Near neutral pH Stress Corrosion Cracking (NNpHSCC) associated with external corrosion of pipelines is an issue facing industry today. Determining areas of NNpHSCC susceptibility is crucial to developing Integrity Management Programs and inspection dig schedules. This research involved collecting pertinent field data (inspection dig reports, failure reports, loading histories) and developing a predictive model to help identify areas and lines most susceptible to NNpHSCC. The predictive model focused on the loading history (in this case, SCADA data) patterns to classify different groups of loading conditions. Hydrogen has been identified and established in previous literature to be a major contributor to NNpHSCC. Different Hydrogen Enhancement Factors (HEF) were applied based on how the mechanisms of hydrogen embrittlement react to the respective loading conditions. The predictive model illustrated a dormancy behaviour, similar to the one seen in field conditions and a mechanically activated growth dependent on both hydrogen and previous loading scenarios. A correlation was shown between a limited field sampling and the predicted values. Further improvements and calibrations can be made with the gathering of more field data and continued experimental validation. Once this validation has been performed, this model has the possibility to illustrate what loading conditions increase a segments susceptibility to NNpHSCC.


Author(s):  
Weixing Chen ◽  
Sheng-Hui Wang

Room temperature creep is often of significant importance in structural materials. Its occurrence, for example, may be an important factor contributing to crack growth during stress corrosion cracking. For pipeline steels used in gas transmission, room temperature creep deformation near the crack tip may result in a time dependent crack growth. In this research, room temperature creep of two pipeline steels with different grades was studied under various loading conditions including pure static, pure cyclic and a combination of static and cyclic loading. The creep deformation under a stress higher than the yield strength may represent the deformation behaviour at the crack tip. Due to cyclic hardening, all the steels crept at a stress higher than the yield strength exhibit cyclic creep retardation, which is less pronounced at lower stress-ratio (minimum stress/maximum stress). Pre-cyclic loading has significant effect on subsequent static creep. In general, pre-cyclic loading causes a burst of creep deformation under subsequent static loading, which may result in significantly larger cumulative creep strain than that of pure static creep depending on the initial loading strain and the number of cycles in pre-cyclic loading. The burst in creep deformation requires an incubation period that increases with number of prior load cycles. The burst strain is dependent on the number of cycles of prior cyclic loading in a more complicated manner. The implication of the creep behaviour observed in these tests is also discussed in terms of stress corrosion cracking in the pipeline steels.


Alloy Digest ◽  
1969 ◽  
Vol 18 (6) ◽  

Abstract AMBRONZE 413 is a copper-tin bronze recommended for plater's plates and electrical contact springs. It is relatively immune to stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-201. Producer or source: Anaconda American Brass Company.


Alloy Digest ◽  
1985 ◽  
Vol 34 (11) ◽  

Abstract NICROFER 5716 HMoW is a nickel-chromium-molybdenum alloy with tungsten and extremely low carbon and silicon contents. It has excellent resistance to crevice corrosion, pitting and stress-corrosion cracking. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: Ni-324. Producer or source: Vereingte Deutsche Metallwerke AG.


Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  

Abstract NAS 825 is a corrosion-resistant nickel alloy that has resistance to both oxidizing and reducing environments, and with 42% nickel, the alloy is very resistant to chloride-ion stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-694. Producer or source: Nippon Yakin Kogyo Company Ltd.


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