Data for: Effect of Niobium on Sulfide Stress Cracking Behavior of Tempered Martensitic Steel

Fig. I is the rising permeation transients of samples with different Nb content in form of normalized flux [J(t)/Jss] and logarithm of normalized time τ for comparison with the theoretical curve.Where τ=DLt/L2, J(t)=I(t)/AF and a value of 1.45×10-5 cm2/s was used for the scaling parameter of lattice diffusion coefficient DL. It can be seen in Fig. I that the normalized permeation transients are all steeper than predicted from Fick’s second law, indicating that trap occupancy is significant.
Fig.II is the hydrogen permeation curves for as-tempered 30 Nb steel with three different specimen thicknesses.
Fig.III is the normalized hydrogen permeation curves of as-tempered 30 Nb steel with three different specimen thicknesses.It indicates that the permeation currents show good agreement after normalizing, suggesting that hydrogen transport shows independence of thickness and is under bulk/volume rather than surface control.
Fig.3 to Fig. 18 correspond to the raw or processed data in the manuscript.