Environmentally assisted cracking

The strains needed to initiate cracks in both the annealed and the sensitised materials were obtained using tapered slow-strain-rate specimens and the data are given in Fig. 8.36. As can be seen, there is little temperature dependence of the strain needed to initiate cracks in sensitised material whereas the annealed material was most susceptible to cracking at about 250°C. These results indicate the complicated response of Type 316 stainless steel to applied potential and demonstrate that, even though environmentally-assisted cracking may be generated by severe test methods, in this case the slow-strain-rate test, the results obtained must be used with care. For instance, the cracking of the annealed material at low potentials... 

P. L. Andresen, F. P. Ford. Proc. ASME Symp. on Predictive Capabilities in Environmentally Assisted Cracking, Miami, 17 (Nov. 1985). 

G129, Standard Practice for Slow-Strain Rate Testing to Evaluate the Susceptibility of Metallic Materials to Environmentally Assisted Cracking, ASTM, West Conshohoken, PA, 1995. 

Mechanisms of Environmentally Induced Cracking (EIC). Environmentally assisted cracking spans a wide range from brittle fracture to electrochemical process and the underlying mechanisms are complex. 

Elboujdaini, M., Shehata, M.T., A Review on the Initiation of Environmentally Assisted Cracking in Line Pipe Steel, Proceedings of the Egyptian Corrosion Society, pp. 1-13, December 2004. 

Chuan, M. and Tseng, W., Environmentally assisted cracking behaviour of single and dual phase stainless steel in hot chloride solution, Materials chemistry and physics, 84, pp 162-170, 2004. 

Fig. 6 Environmentally assisted cracking of a weld in a deaerator, caused by a combination of static residual and cyclic operating stresses, and revealed by magnetic particle inspection.

J.R. Scully and P.J. Moran, Influence of Strain on Hydrogen Assisted Cracking of Cathodically Polarized High-Strength Steel, Environmentally Assisted Cracking Science and Engineering, STP 1049, ASTM, 1990, p 5-29... 

Wei, R. P., and Gao, M., Hydrogen Embrittlement and Environmentally Assisted Crack Growth, in Hydrogen Effects on Material Behavior, Neville R. 

Wei, R. P., and Gao, M., Hydrogen Embrittlement and Environmentally Assisted Crack Growth, Hydrogen Effects on Material Behavior, N. R. Moody and A. W. Thompson, eds.. The Mineral, Metals Materials Society, Warren-dale, PA (1990), 789-815. (D. Ressler, M. S. Thesis, Dept, of Mech. Eng g and Mechanics, Lehigh University, Bethlehem, PA, 1984.)... 

Wei, R. P., A Perspective on Environmentally Assisted Crack Growth in Steels, Proceedings of International Conference on Environmental Degradation of Engineering Materials, Gdansk-Jurata, Poland, September 19-23 (1999). 

Wei, R. P., Synergism of Mechanics, Mechanisms and Microstructure in Environmentally Assisted Crack Growth, in FRACTURE Interactions of Microstructure, Mechanisms and Mechanics, J. M. Wells and J. D. Landes, eds.. The Metallurgical Society of AIME, War-rendale, PA (1985), 75-88. 

Chen, S.-F., and Wei, R. P., Environmentally Assisted Crack Growth in a Ni-18Cr-18Fe Ternary Alloy at Elevated Temperatures, Matls Sci. Engr., A256 (1998), 197-207. 

M. A. Gaudett, J. R. Scully, Environmentally Assisted Cracking of High Strength Beta Titanium Alloys, Report to the Office of Naval Research, Grant No. N000014-91-J-4164,1994. 

Environmentally assisted cracking (EAC) occurs not only in metals but also in glasses (Plexiglas), ceramics, and polymers. Structural failures because of EAC can be sudden and unpredictable, occurring after a few hours of exposure or after months or years of satisfactory service (86, 87). The two types of environmentally assisted cracking (EAC) are mechanically assisted cracking and EIC. 

The total cost of material fracture is about 4% of gross domestic product in the United States and Europe (88,89). Fracture modes included in the cost estimates were stress-induced failures (tension, compression, flexure, and shear), overload, deformation, and time-dependent modes, such as fatigue, creep, SCC, and embrittlement. The environmentally assisted corrosion problem is very much involved in the maintenance of the safety and reliability of potentially dangerous engineering systems, such as nuclear power plants, fossil fuel power plants, oil and gas pipelines, oil production platforms, aircraft and aerospace technologies, chemical plants, and so on. Losses because of environmentally assisted cracking (EAC) of materials amount to many billions of dollars annually and is on the increase globally (87). 

EAC environmentally assisted cracking EHS environmental, health, and safety... 

F.P. Ford, Quantitative prediction of environmentally-assisted cracking. Corrosion 52 (1996) 375-395. 

H.P. Seifert, S. Ritter, J. Hickling, Research and service experience with environmentally assisted cracking of low-aHoy steel pressure-boundary components under LWR conditions. Power Plant Chem. 6 (2004) 111-123. 

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