The exact adjustment of the individual microstructural constituents, in particular the optimum volume fraction of metastable retained austenite (RA), is imperative in case of the 3rd generation advanced high strength steels (AHSS). Moreover, it is of vital importance to avoid the formation of fresh martensite (α’) upon final cooling, otherwise the resulting mechanical properties of these novel steel grades will be pronouncedly deteriorated. Therefore, an accurate estimation of the martensite start (Ms) temperature is essential for modelling and development of this steel group. In this context, the present contribution proposes a new relation for the Ms temperature prediction with a remarkably wide composition range based on the 3rd generation AHSS chemistries. Moreover, the new Ms formula allows for an accurate determination of the Ms temperature for both, extremely low and very high C contents, which is not the case in any Ms formula known from literature.
- Martensitic phase transformation
- Metastable phases