Issue 36

F. Z. Liu et alii, Frattura ed Integrità Strutturale, 36 (2016) 139-150; DOI: 10.3221/IGF-ESIS.36.14 143 the content of non-diffusible hydrogen in the samples in tempering state. An obvious low-temperature hydrogen effusion peak appeared in the hydrogen effusion curve of the hydrogen charged samples in quenching state or at different tempering temperatures and the peak temperature was about 145 °C; but no obvious changes were observed in the high- temperature hydrogen effusion peak. Besides, the low-temperature peak of hydrogen filled samples in tempering state was the highest. With the increase of tempering temperature, the low-temperature peak of the samples decreased, but the high- temperature peak had no obvious changes. It suggested that, the hydrogen absorbed after hydrogen charging was diffusible hydrogen and the content of non-diffusible hydrogen had no obvious changes. Figure 4 : Variation of critical fracture stress and delay fracture ratio of the experimental materials along with the changes of tensile strength. Figure 5 : Variation of clinical fracture stress and delay fracture ratio of the experimental materials along with the changes of tempering temperature.