Environmentally Assisted Cracking

EBSD - 25Cr SDSS - Deformation

Environmental cracking or environmentally assisted cracking (EAC) is the cracking of a material wherein an interaction with its environment is a causative factor in conjunction with tensile stress [author’s note: tensile stresses can be applied and/or residual], often resulting in brittle fracture of an otherwise ductile material. [1]


Figure 1 illustrates a sulfide stress cracking (SSC) fracture of a four-point bend specimen made of UNS G41400 low alloy steel in H2S-satudrated NACE solution.


Figure 1. Environmental cracking of low alloy steel UNS G41400 (AISI 4140) in 50 g/l NaCl + 4 g/l sodium acetate (CH3COONa) saturated with high purity H2S gas at room temperature and atmospheric pressure.


  1. ASTM G193–12d "Standard Terminology and Acronyms Relating to Corrosion, ASTM International, West Conshohocken, PA, 2003, DOI:10.1520/G0193–12D, www.astm.org.


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