Effect of Hydrogen on Low Cycle Fatigue of S45C Carbon Steel under Non-proportional loading

Abstract

In order to reveal the effects of hydrogen on the non-proportional low cycle fatigue of a carbon steel JIS-S45C, strain controlled low cycle fatigue tests were carried out under push-pull, reversed torsion and circle loadings using hydrogen charged and uncharged specimens. The specimens were polished with buff, and then were charged hydrogen by immersing in 20 mass% NH₄SCN solution at 313 K for 48 hours. The fatigue life reduction rate under circle loading is 16% at Mises strain range Δε_eq = 0.5% and 1.0%, which is smaller than that of push-pull loading. However, at Δε_eq = 1.5%, the fatigue life reduction rate under circle loading is 49%, which is the largest reduction rate in all test conditions.