The ductile to brittle transition temperature
(TT) for SCWE has been measured by drop
weight test. Interstitial free steels are known
to be very sensitive to SCWE. In the case of
rephosphorized IF steels, their high transition
temperatures, close to room temperature,
can even be redhibitory in some applications.
The introduction of solute carbon, at
least on a part of the thickness increases the
grain boundary cohesion and then improves
the resistance of sensitive steels to SCWE.
This beneficial decrease of transition temperature obtained by carburizing has been
observed for IF-Ti and IT-Ti-P steel grades whatever the applied reactive annealing cycle