Considerations in development of CCT diagrams for complex ferritic materials

Abstract

A recent literature review of available data for the bainitic creep strength enhanced ferritic steel grade 23 revealed significant variations among available continuous cooling transformation (CCT) diagrams. Substantial differences in these diagrams were noted with respect to the observed transformation products, reported transformation temperatures and the data provided with the CCT diagram. While it is recognised that grade 23 is a complex material exhibiting up to three transformations on-cooling from austenitisation, there does not seem to be a standardised or uniform procedure for the development of CCT diagrams for such metallurgically diverse materials. This paper details development of a CCT diagram for this material through integration of results from thermal analysis, hardness measurements and microstructural observations.

Keywords

Continuous cooling transformation diagram Creep strength enhanced ferritic steel Grade 23 T/P23

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