TY - JOUR
T1 - Small fatigue crack growth characteristics and fracture surface morphology of low carbon steel in hydrogen gas
AU - Lee, Dongsun
AU - Nishikawa, Hideaki
AU - Oda, Yasuji
AU - Noguchi, Hiroshi
N1 - Funding Information:
Acknowledgments This study was conducted as a part of the “Fundamental Research Project on Advanced Hydrogen Science” funded by New Energy and Industrial Technology Development Organization (NEDO).
PY - 2013/1
Y1 - 2013/1
N2 - Owing to energy conservation and environmental concerns, hydrogen has been suggested as a next-generation energy source. However, hydrogen known to seep into a metal, degrade its strength, and accelerate fatigue crack growth rates. We have investigated the effects of hydrogen gas on the small fatigue crack growth characteristics of low carbon steel JIS S10C by conducting bending fatigue tests on a specimen with a small blind hole and placed in a low-pressure hydrogen environment. The fatigue crack growth rate in hydrogen was higher than that in nitrogen. The fracture surface of the specimen in hydrogen showed intergranular facets in the low- growth-rate range and a quasi-cleavage fracture surface with brittle striations in the high-growth-rate range. The specimen only showed a ductile fracture surface for nitrogen. The small-fatigue-crack growth rate for nitrogen is given by dl/dN ∞Δp nl, where l, N, and Δp represent the crack length, number of repetitions, and plastic strain range, respectively. This equation was also satisfied for hydrogen, but only over a short strain range from Δi = 0.25 to 0.37% in which the fracture surface exhibited intergranular facets and a ductile morphology, but no quasi-cleavage fracture. The exponent n of the equation was 1.22 in nitrogen and 0.66 in hydrogen environment. The small-fatigue-crack growth law can be used for safe material designs in hydrogen environments.
AB - Owing to energy conservation and environmental concerns, hydrogen has been suggested as a next-generation energy source. However, hydrogen known to seep into a metal, degrade its strength, and accelerate fatigue crack growth rates. We have investigated the effects of hydrogen gas on the small fatigue crack growth characteristics of low carbon steel JIS S10C by conducting bending fatigue tests on a specimen with a small blind hole and placed in a low-pressure hydrogen environment. The fatigue crack growth rate in hydrogen was higher than that in nitrogen. The fracture surface of the specimen in hydrogen showed intergranular facets in the low- growth-rate range and a quasi-cleavage fracture surface with brittle striations in the high-growth-rate range. The specimen only showed a ductile fracture surface for nitrogen. The small-fatigue-crack growth rate for nitrogen is given by dl/dN ∞Δp nl, where l, N, and Δp represent the crack length, number of repetitions, and plastic strain range, respectively. This equation was also satisfied for hydrogen, but only over a short strain range from Δi = 0.25 to 0.37% in which the fracture surface exhibited intergranular facets and a ductile morphology, but no quasi-cleavage fracture. The exponent n of the equation was 1.22 in nitrogen and 0.66 in hydrogen environment. The small-fatigue-crack growth law can be used for safe material designs in hydrogen environments.
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U2 - 10.1007/s10704-012-9783-2
DO - 10.1007/s10704-012-9783-2
M3 - Article
AN - SCOPUS:84871667137
SN - 0376-9429
VL - 179
SP - 147
EP - 156
JO - International Journal of Fracture
JF - International Journal of Fracture
IS - 1-2
ER -
