Effects of Hydrogen Charge on Cyclic Stress-Strain Properties and Fatigue Behavior of Carbon Steels

Abstract

Effects of hydrogen charge on fatigue behaviour of two carbon steels, JIS-S10C (SAE1010) and JIS-S45C (SAE1045) were investigated. There was no hydrogen effect in the cyclic stress-strain hysteresis loops of S10C hydrogen-charged with 0.2 ppm. On the other hand, the strain amplitude was decreased in S45C hydrogen-charged with 0.8 ppm. The delayed yielding and the decrease in the saturated value of the strain amplitude were observed in the hydrogen-charged specimen (H : 0.5 ppm) of S45C under the constant stress amplitude tests. It is supposed that the degree of influence of hydrogen on cyclic stress-strain properties depends or material structure and/or hydrogen content. The effect of hydrogen charge (H : 0.5 ppm) on the fatigue life, the fatigue limit and the crack growth curves of S45C were not remarkable, while there was a distinct difference in the morphology of the slip bands between the hydrogen-charged and uncharged specimens. The localized slip bands were observed in the hydrogen-charged specimen of S45C. Therefore, it is presumed that the decrease in the strain amplitude in hysteresis loop by hydrogen charge is caused by the localization of slip bands. More crack initiations from ferrite grains were observed in the hydrogen-charged specimen (H : 0.5 ppm) of S45C. This phenomenon also corresponds to the localization and the formation of slip bands.

The Effect of Hydrogen on Fatigue Properties of Metals used for Fuel Cell System

“…Figure 33 shows the S-N data for the uncharged and hydrogen-charged 0.47%C steel (Uyama et al, 2004). Figures 34a and b show that there is a clear difference in slip band morphology between the uncharged and hydrogen charged specimen (Uyama et al, 2004). Slip bands in the uncharged specimens (Figure 34a) gradually spread throughout and finally completely covered the ferrite grains with increasing number of cycles.…”

“…The specimen surface of 0.45%C was finished by electropolishing after the charging. Figure 33 shows the S-N data for the uncharged and hydrogen-charged 0.47%C steel (Uyama et al, 2004). Figures 34a and b show that there is a clear difference in slip band morphology between the uncharged and hydrogen charged specimen (Uyama et al, 2004).…”

“…Tension-compression S-N data of the unnotched specimens of an annealed 0.47%C steel with and without hydrogen charging(Uyama et al, 2004). (Hydrogen content was measured 2 h after the hydrogen charging.)…”

Investigation of Mechanism for Intergranular Fatigue Crack Propagation of Low Carbon Steel JIS S10C in Hydrogen Gas Environment

“…Therefore, S10C is adopted not only as the actual material whose chemical composition of S10C is similar to that of pipe-line steel, but also as the material which is suitable for the basic research of the FCG mechanism. It is well-known that hydrogen affects slip behavior (8), (9) . Therefore, it is possible that the grain boundary is damaged (microvoid, microcrack) by slips produced by hydrogen.…”

“…Furthermore, it was shown that the IG damage was caused by transgranular slip. It has been reported that hydrogen affects transgranular slip (8), (9) . As in previous studies, hydrogen affects the transgranular slip and the slip easily causes the IG damage.…”