The role which was played by H trapping in steel was reviewed. Such trapping increased the H solubility and decreased its diffusivity. The traps could be characterized in terms of their nature: reversible or irreversible, saturable or non-saturable. A dislocation core was considered to be a saturable reversible trap, while voids and cracks were non-saturable reversible traps. A trap model was developed which was based upon saturable reversible traps. In equilibrium, the trap model corresponded to Oriani's trap model. The trap density increased as the plastic strain increased. By using the trap data, it was shown that equilibrium between the H in lattice sites and trap sites could be assumed when strain rates were used as in standard tensile tests.

Hydrogen Trapping Models in Steel. A.H.M.Krom, A.Bakker: Metallurgical and Materials Transactions B, 2000, 31[6], 1475-82