PSI - Issue 79

Jorge Luis González-Velázquez et al. / Procedia Structural Integrity 79 (2026) 526–533

531

Fig. 4. HIC area with respect to cathodic charging time for the: a) NG and b) NG steel plates.

OG

NG

Fig. 5. Plots of HIC growth rate as a function of H-solubility ( C app ) and density of reversible traps (  RT )

The typical HMT results for each group of tested steels are shown in Fig. 6. It is observed that hydrogen atoms accumulated around pearlite islands in OG steels but in NG steels hydrogen diffusion is through blocky martensite/austenite but is more intense around NMI inclusions of cuboidal shapes. The IPF maps obtained from the EBSD results are shown in Fig. 7. They show that the HIC propagated along transgranular paths in all tested specimens; but in OG steels, the cracks propagated along at the ferrite/pearlite bands. The KAM maps show that the pearlite/ferrite bands have high misorientations that facilitated the nucleation of HIC, and HIC crack propagated through the deformed or recovered grains which the stored energy of deformation was higher than that in recrystallized grains. Finally, as observed in Fig. 7, high-angle grain boundaries facilitated HIC regardless of the microstructure, namely the generation of the steel.