Fatigue Crack Propagation in Gaseous Hydrogen Environment in Low Alloy Steel Fatigue Crack Propagation in Gaseous Hydrogen Environment in Low Alloy Steel ScienceDirect Fatigue crack propagation in gaseous hydrogen environment in low alloy steel

Christine Sarrazin-Baudoux, Catherine Gardin, Tuan Pham, Gaëlle Chretien, Jean Petit, Van-Xuan Tran, Guillaume Benoit, Christine Sarrazin-Baudoux, Catherine Gardin, Tuan Pham, Gaëlle Chretien, Jean Petit (+9 others)
2015 Procedia Engineering   unpublished
Fatigue crack propagation in low alloyed steel (3.5Ni-1.5Cr-0.5Mo-V) used for turbine generator of nuclear plant is studied under 4 bar hydrogen atmosphere in comparison to ambient air and high vacuum. Tests are conducted on CT specimens and the variation of the fatigue crack growth rate da/dN with respect to the amplitude of the applied stress intensity factor K is explored in a wide range and especially in the near threshold domain. The propagation behaviour under hydrogen atmosphere is shown
more » ... similar to that obtained in air in the low rate range, i.e. when the maximum of the stress intensity factor K max is lower than a critical level of 16 MPam 1/ 2 with higher crack growth rate than in high vacuum. This environment effect is related to the presence of residual water vapour in both gases. For K max higher than 16 MPam 1/2 , much faster growth rates under hydrogen atmosphere in comparison to air and vacuum are observed and related to hydrogen assisted intergranular propagation combining fatigue and sustained loading damage. The results are discussed on the basis of micrographic observations supporting the involved mechanisms.
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