Case Histories Involving Stress Corrosion Cracking of Various Alloys

Stress corrosion cracking (SCC) can lead to rapid and catastrophic failure in many different metals and alloys. This phenomenon occurs under conditions where a component is exposed to a mildly corrosive substance while under applied and/or residual tensile stress. Since this type of cracking does not generally result in significant surface appearance changes or elongation, failures often occur with little or no prior warning. A systematic approach is needed to evaluate any failure and identify its physical cause, and the proper use of such an approach will greatly increase the likelihood of successful failure mode identification and appropriate corrective action counsel. SCC results in the development of certain characteristic features that can be recognized by an experienced analyst during the course of a comprehensive failure investigation. The case histories within this article illustrate features that are commonly evident in various materials that experience SCC.