Issue 36

F. Z. Liu et alii, Frattura ed Integrità Strutturale, 36 (2016) 139-150; DOI: 10.3221/IGF-ESIS.36.14

Fig. 6 shows the variation of the hydrogen content of the experimental materials in different states along with the changes of tempering temperature. It can be seen that, the content of hydrogen in different states before hydrogen charging were similar; the content of diffusible hydrogen was quite low; except for samples processed at a tempering temperature of 100 °C, the content of non-diffusible hydrogen in samples in different states was highly consistent; the content of hydrogen significantly improved after hydrogen charging, a slight increase in non-diffusible hydrogen and a significantly increase in diffusible hydrogen; as the tempering temperature increased, the content of hydrogen charged reduced (the content of diffusible hydrogen decreased and the content of non-diffusible hydrogen remained unchanged).

100 °C tempering state

200 °C tempering state

400 °C tempering state

Quenching state

State of samples

The content of diffusible hydrogen (ppm) The content of non- diffusible hydrogen (ppm) Total content of hydrogen (ppm) The content of diffusible hydrogen(ppm) The content of non- diffusible hydrogen (ppm) Total content of hydrogen (ppm)

0.0176

0.0081

0.0009

0.0031

Samples without hydrogen charging (original state)

0.0741

0.1677

0.0791

0.0834

0.0909

0.1758

0.0801

0.0857

0.8629

0.6201

0.5452

0.4441

Hydrogen-filled samples

0.1134

0.0951

0.1402

0.1443

0.9771 0.5882 Table 3 : The content of hydrogen of the experimental materials in different states before and after hydrogen charging (non-bearing, round bar samples). 0.7136 0.6866

Figure 6 : Vibration of the content of hydrogen of round bar samples in different states before and after hydrogen charging (C d : the content of diffusible hydrogen; Cn: the content of non-diffusible hydrogen; Ct: the content of hydrogen). Hydrogen absorption and effusion behaviors of experimental materials before and after loading The notch tensile samples were loaded for 100 hours in corrosive liquid under critical stress. Then the corroded part was cut down. After surface clearance, it was put into TDS to measure behaviors of hydrogen absorption and effusion, and the measurements results are shown in Tab. 4 and Fig. 8. It can be seen that, the content of hydrogen in samples in four

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