Diffusion coefficients were measured in alloy steels, at temperatures of between 370 and 620C, by using the time-lag method. It was found that alloying decreased the diffusion coefficient (tables 55 and 56).
O.F.Angeles, R.J.Stueber, G.H.Geiger: Corrosion, 1976, 32[5], 179-83
Table 55
Diffusivity of H in 1Cr-½%Mo Steel
Temperature (F) | PH2 (psig) | D (cm2/s) |
700 | 600 | 9.8 x 10-5 |
700 | 1000 | 6.6 x 10-5 |
850 | 600 | 8.70 x 10-4 |
850 | 1000 | 1.19 x 10-4 |
1000 | 250 | 1.44 x 10-4 |
1000 | 600 | 1.55 x 10-4 |
1000 | 1000 | 1.69 x 10-4 |
1150 | 600 | 1.84 x 10-4 |
Table 56
Diffusivity of H in 2¼Cr-1%Mo Steel
Temperature (F) | PH2 (psig) | D (cm2/s) |
700 | 1000 | 1.01 x 10-4 |
850 | 250 | 0.88 x 10-4 |
850 | 500 | 1.50 x 10-4 |
850 | 1000 | 1.17 x 10-4 |
1000 | 125 | 1.22 x 10-4 |
1000 | 500 | 1.34 x 10-4 |
1000 | 1000 | 1.43 x 10-4 |