Effects of Large Amount of Hydrogen and Frequency on Fatigue Properties of Carbon Steel

The effects of a large amount of hydrogen and the frequency on the fatigue crack growth behavior of carbon steel were investigated. Hydrogen-pre-charged specimens were produced by performing cathodic and immersion charging on virgin or torsionally pre-strained carbon steels. Rotating bending fatigue tests were conducted in air at room temperature. The crack growth acceleration due to hydrogen did not exceed more than a factor of 30 when the frequency, f, ranged from 0.03 Hz to 3.2 Hz, which means there was an upper limit, even in the case of lower test frequencies. There was no clear difference in effect of hydrogen on non-propagating cracks at frequencies, f, of 3 Hz and 30 Hz.