Evolution curves, for cold-worked pearlite in the 0.8%C steel, exhibited 2 stages at 100C. A single stage was observed at 400C for this material, and for tempered martensite at either temperature. The 2 evolution stages at the lower temperature were associated with traps with differing binding energies. The evolution of H at 400C was considered to be diffusion-controlled in both steels. The diffusion coefficients at this temperature were equal to 1.4 x 10-9 and 2.1 x 10-9m2/s in pearlite and martensite, respectively.

E.Strecker, D.A.Ryder, T.J.Davies: Metal Technology, 1975, 2[5], 236-7