Abstract
De-embrittlement behavior of 3.5% Ni-Cr-Mo-V steel was studied by rapid induction heating to three different temperatures above the embrittling temperature range, holding for several seconds, and quenching Charpy specimens embrittled in advance.
The main conclusions obtained are as follows;
(1) FATT (Fracture Appearance Transition Temp.) is reverted to its original non-embrittled value within a few seconds at a high temperature and the increasing temperature increases the reversion rate.
(2) FATT cannot revert completely by lower temperature annealing even with long time holding.
(3) Activation energy necessary for the de-embrittling process is about 61 kcal/mol and the process may be controlled by diffusion of phosphorus.
