Brittle-to-ductile transition behavior is one important aspect in the material behavior of ferritic steels. Because of the many influencing parameters involved, the transition behavior is known to cause great difficulties in its theoretical treatment and modeling as well as in the development of a sufficiently reliable empirical correlation. In spite of this, some means have to be provided to treat or characterize brittle-to-ductile transition behavior in an appropriate or at least in an acceptable way, especially for integrity assessments of components.

In this paper, some basic considerations and treatments of brittle-to-ductile transition, as well as relevant influencing parameters and their effects, will be discussed. Also, experimental results will be presented and conclusions drawn and new aspects discussed that can have significant consequences in the application of structural integrity assessment methods.