PSI - Issue 26

Myroslava Hredil et al. / Procedia Structural Integrity 26 (2020) 409–416 Hredil et al. / Structural Integrity Procedia 00 (2020) 000 – 000

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higher cleavage ridges separating the adjacent fatigue festoons, which create favorable conditions for crack closure effect. Soil solution under fatigue testing promotes occurrence of intergranular fracture elements with secondary microcracking, more noticeable in operated steels. Simulation of working conditions of gas pipelines proved that hydrogen formed at the inner pipe surface can penetrate pipe wall and facilitate the crack growth at the outer pipe surface. Both in-laboratory and operational steel degradation methods lead to cohesion weakening between adjacent grains, manifested by appearance of intergranular fracture elements, and secondary microcracking.

Acknowledgements

This research has been supported by the NATO in the Science for Peace and Security Programme under the Project G5055.

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