<p>Currently, the availability of commercial steels for additive manufacturing (AM) is restricted. Consequently, there is a need to proceed in the development of novel steel grades that can address the limitations of the presently available steels in the market. In this regard, high Mn steel are considered as a promising option due to their ability to provide great combinations of high strength and ductility, in combination with a relatively low density. These properties make these steels suitable for deployment in structural applications. On the other hand, as typical microstructures in laser powder bed fusion (L-PBF) are formed by elongated grains aligned with the building direction, the objective of this study is to investigate the formation of in-situ inoculation in these high Mn steels in L-PBF by modifying the solidification path through the addition of different amounts of Ti. This is accomplished using the calculation of phase diagrams (CALPHAD) approach, which allows for a thermodynamic and phase transformation analysis of the systems. The accuracy of CALPHAD predictions and the effectiveness of in-situ formed inoculants in grain refining are evaluated through microstructural observations conducted on both powder and printed parts. Finally, the evaluation of mechanical properties is carried out on as-printed steels with different grain sizes to determine the range of mechanical properties that can be achieved by these steel grades.</p>