Analysis of intergranular stress corrosion crack paths in gas pipeline steels; straight or inclined?

By Lavigne, Olivier; Gamboa, Erwin; Luzin, Vladimir; Law, Michael
Published in Engineering Failure Analysis 2018

Abstract

The failure analysis conducted on an X42 pipe steel showed that the combination of the operating and residual (mainly bending) stresses may have been sufficient to exceed the threshold stress for high pH stress corrosion cracking (SCC) to initiate, in the course of normal operating stresses and temperature. Comparison of the results obtained in this study for the X42 pipe sample (showing straight SCC cracks) together with those published previously for X65 pipe samples (showing inclined SCC cracks) suggested that the interdependency of crack tip plasticity, anisotropy in microstructural texture and residual stresses affect the resulting crack paths. The SCC crack paths are therefore believed to be dictated by the interdependency of the pipe manufacturing (residual stress, texture) and operating pressure parameters.

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