History of ductile-to-brittle transition problem of ferritic steels

This paper presents a review of different approaches through history concerning DTB transition phenomenon of ferritic steels and their characterization using FM concept, from the earliest studies based on LEFM to the application of the EPFM concept. The large scattering of the experimental fracture toughness data, characteristic of all ferritic steels in the transition temperature region, has imposed the need of including statistical methods for data processing. Such approach that began in the 1970s can be encountered even nowadays as the base of fracture toughness data interpretation in DTB problems. An overview of studies with statistical interpretation of experimental data in the transition temperature region is also given. Aforementioned provides a foundation for novel approaches in DTB transition problems, which include size effects and scaling of geometrically similar specimens.