水素ステーション蓄圧器用SCM435鋼の疲労特性に及ぼす水素と繰返し速度の影響(<小特集>水素エネルギーシステムに使用される材料の強度問題)

概要

論文の詳細を見る
Fatigue tests on SCM435 steel quenched at 860℃ and tempered at 580℃ were carried out under the frequencies of 0.2, 2 and 20Hz with specimens containing a small artificial hole. An additional test in which the frequency was alternatively switched between 0.02Hz and 2Hz was also carried out. Hydrogen charging to specimens was carried out by immersion method. The fatigue life of hydrogen-charged specimens decreased in comparison with that of uncharged specimens. The acceleration of fatigue crack growth rate da/dN was observed at da/dN<1.0×10^<-7>m/cycle in test frequency f=20Hz, da/dN<4.0×10^<-7>m/cycle in f=2Hz and da/dN<1.5×10^<-6>m/cycle in f=0.2Hz. The acceleration of da/dN saturated at ΔK<17MPa√m in f≤2Hz. It was found that there is the upper bound of the effects of hydrogen and test frequency on fatigue crack growth rate in hydrogen environment. The test with switching two frequencies between 0.02Hz and 2Hz showed that hydrogen concentration in the vicinity of the crack tip remarkably affects fatigue crack growth behavior and crack morphology. The most remarkable change of the slip bands around the crack tip was less and discrete in the hydrogen-charged specimens compared to uncharged specimens.
社団法人日本機械学会の論文
2007-12-25