Fatigue Characteristics of Low Carbon Steel in Hydrogen Gas Environment

Author(s):  
Hiroshi Noguchi ◽  
Yasuji Oda
2007 ◽  
Vol 345-346 ◽  
pp. 1051-1054 ◽  
Author(s):  
Hiroshi Noguchi ◽  
Yasuji Oda

In order to investigate the effect of hydrogen environment on fatigue crack growth characteristics of a low carbon steel JIS S10C, fatigue crack growth tests were conducted in a low pressure hydrogen gas environment. Fatigue crack growth rate in hygrogen gas is higher than that in nitrogen gas. It seems that a crack in the range of low growth rate prefers to propagate along the grain boundaries under hydrogen environment while in the range of high growth across the grains accompanied by brittle striation patterns or river patterns. It is important to clarify how hydrogen affects the crack growth behavior of different stages of crack growth.


2011 ◽  
Vol 488-489 ◽  
pp. 323-326
Author(s):  
A. Nishimoto ◽  
Yasuji Oda ◽  
Hiroshi Noguchi

Loading frequency effects on FCGR and fracture surface morphology were investigated on pre-strained low carbon steel in high FCGR range. Loading frequency effects showed the different trend between internal hydrogen and environmental hydrogen. The effects of combined condition hydrogen revealed similar tendency of environmental hydrogen.


2007 ◽  
Vol 567-568 ◽  
pp. 329-332 ◽  
Author(s):  
Kyohei Kawamoto ◽  
Yasuji Oda ◽  
Hiroshi Noguchi

In order to investigate the hydrogen effect on fatigue crack growth (FCG) behavior in a few kinds of practical alloys; austenitic stainless steels (solution-treated metastable type 304 and stable type 316L), an aluminum alloy (age-hardened 6061) and a low carbon steel (annealed 0.13%C-Fe), FCG tests were carried out in hydrogen gas and in nitrogen gas. The FCG rates of these materials are enhanced by hydrogen, though the acceleration degrees are different. A crack grows across grains by slip-off in 316L stainless steel and in age-hardened 6061 aluminum alloys even in hydrogen. Faceted area increases in 304 stainless steel and in low carbon steel in hydrogen. In 304 stainless steel, the ratio of facets to the entire fracture surface was not so large. Thus, the FCG rate is not significantly affected through the facets in 304 stainless steel. In low carbon steel, facets were increased considerably, though a crack grows step by step or after a large number of loading cycles even along grain boundaries. Anyhow hydrogen enhances the FCG rate of these materials through the influence on slip behavior. Based on above-mentioned results, the effect of loading frequency on FCG rate in hydrogen of the age-hardened 6061 aluminum alloy was also investigated. The FCG rate increases as the testing frequency decreases, though the FCG rate in hydrogen shows the tendency to saturate.


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