Hydrogen gas effects on the fatigue crack growth behavior of Cr-Mo Steel CT specimen in extremely low rate range

Koki Tazoe, Yasuji Oda, Hiroshi Noguchi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In order to investigate extremely slow fatigue crack growth characteristics of JIS SCM440 CT specimen in 9 MPa hydrogen gas environment, stress intensity factor range (ΔK) decreasing tests with in-situ observation were carried out. Fatigue crack growth rate (FCGR) in hydrogen gas did not show threshold behavior but FCGR in helium and air showed threshold behavior clearly. Fatigue crack in hydrogen gas showed sudden increased after a temporary stop in growth. The sudden increase in growth was induced by coalescing with a new micro-crack initiated in front of the main crack tip. The fractographic analysis showed the existence of intergranular facets. The intergranular facets were observed in all over the fracture surface. The amount of the intergranular facets in hydrogen gas decreased with decreasing the ΔK. However, facets were still observed in the extremely low rate region. On the other hand, there was no facet in fracture surface tested in helium and in air in the extremely low rate region. The formation of facets was supposed to be one of the causes of non-threshold behavior in hydrogen gas.

Original languageEnglish
Title of host publication19th European Conference on Fracture
Subtitle of host publicationFracture Mechanics for Durability, Reliability and Safety, ECF 2012
PublisherEuropean Conference on Fracture, ECF
ISBN (Print)978-5-905576-18-8
Publication statusPublished - Jan 1 2012
Event19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012 - Kazan, Russian Federation
Duration: Aug 26 2012Aug 31 2012

Publication series

Name19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012

Other

Other19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012
CountryRussian Federation
CityKazan
Period8/26/128/31/12

All Science Journal Classification (ASJC) codes

  • Safety, Risk, Reliability and Quality

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  • Cite this

    Tazoe, K., Oda, Y., & Noguchi, H. (2012). Hydrogen gas effects on the fatigue crack growth behavior of Cr-Mo Steel CT specimen in extremely low rate range. In 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012 (19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012). European Conference on Fracture, ECF.