Hastelloy X is a solid solution strengthened Ni base superalloy of known high crack susceptibility during SLM processing. Segregation of alloying elements during solidification stage results in local variation in composition which induces cracking in building direction. The influence of chemical composition on crack susceptibility has been analyzed for Hastelloy X. Four powders have been considered in the present work with different content in the following alloying elements: silicon (Si) manganese (Mn) carbon (C) and nitrogen (N). Process optimization has been carried out for each one of the alloys considering porosity cracks and lack of fusion defects. Defect free material has been achieved for one of the Hastelloy X compositions considered. A deep metallographic characterization by scanning electron microscopy and EBSD technique has been carried out in order to explain the cause of residual cracking.