It was found that, at temperatures ranging from 90 to 330C, the temperature dependences of H diffusivity, permeability and solubility in the 0.2C-13Cr martensitic stainless steel could be described by:

D m2/s) = 2.82 x 10-7exp[-34.36(kJ/mol)/RT]

P (mol/msMPa½) = 6.98 x 10-5exp[-43.93(kJ/mol)/RT]

S (mol/m3MPa½) = 2.48 x 102exp[-9.57(kJ/mol)/RT]

In the present temperature range, the H permeability in martensitic alloy steels was about an order of magnitude lower than that in -Fe, but was 1 to 3 orders of magnitude higher than in austenitic stainless steels. The H diffusivity was 2 to 4 orders of magnitude lower than in -Fe, and was 2 to 3 orders of magnitude higher than in austenitic stainless steels. In the martensitic alloy steels, the increased C content and the existence of retained austenite could result in a decrease in H diffusivity, but would have little effect upon the H permeability.

Hydrogen Permeation and Diffusion in a 0.2C-13Cr Martensitic Stainless Steel. J.Xu, X.Z.Yuan, X.K.Sun, B.M.Wei: Scripta Metallurgica et Materialia, 1993, 29[7], 925-30