A sensitive gas-phase technique was used to measure the transport parameters at 600 to 700K. It was found that the diffusivity of H in the stainless steel increased as the degree of sensitization increased.

as-received:     D (cm2/s) = 1.03 x 10-4 exp[-36.20(kJ/mol)/RT]

annealed (923K, 1.5h):     D (cm2/s) = 3.47 x 10-5 exp[-29.52(kJ/mol)/RT]

annealed (923K, 3.0h):     D (cm2/s) = 7.47 x 10-6 exp[-19.02(kJ/mol)/RT]

This was attributed to the depletion of Cr at the grain boundaries.

D.L.Johnson, D.A.Davis: Scripta Metallurgica, 1989, 23[3], 321-6