An investigation was made of the diffusion of H into steel specimens which had various structures (table 48), but the same composition (0.54C, 0.35Si, 0.65Mn), by using cathodic H charging in 5% H2SO4 solution at a current density of 0.2A/cm2.

I.Onishi, Y.Kikuta, T.Araki, F.Tanichi, T.Fujii: Yosetsu Gakkaishi, 1967, 36[11], 1188-93

 

Table 48

Room-Temperature Diffusivity of H in 0.5%C Steel

 

Microstructure

D (cm2/s)

ferrite + pearlite

4.0 x 10-7

sorbite

3.5 x 10-7

troostite

3.2 x 10-7

martensite

2.5 x 10-7