1977 Volume 63 Issue 7 Pages 1126-1133
The effect of Mo content on de-embrittling behavior of 3.5% Ni-Cr-Mo-V steels was studied. Charpy specimens temper embrittled were rapidly heated to three defferent temperatures above the embrittling range and held for several seconds followed by quenching in water, using a high frequency heating device.
The main conclusions obtained are as follows:
(1) De-embrittlement behavior is rate-controlled by the diffusion process of embrittling species from prior austenite grain boundary to matrix and the diffusion rate is minimized by 0.25% Mo addition. Either decreasing or increasing Mo content leads to the increasing diffusion rate of embrittling species.
(2) The activation energy for diffusion, 40kcal/mol, is independent on Mo content.
(3) The variation of D with Mo content is in good agreement with the change of embrittling tendency with Mo content.