Abstract: A process for manufacturing an additively-manufactured part from a metal powder having a composition having the following elements, expressed in content by weight: 6%?Ni?14%, 5%?Cr?10%, 0.5%?Si?2.5%, 0.5%?Ti?2%, C?0.04% and optionally containing 0.5%?Cu?2%, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a microstructure including in area fraction more than 98% of a body-centered cubic crystalline phase, the process having a step during which at least a part of the metal powder is melted in an atmosphere substantially composed of an inert gas other than Argon or of a combination of inert gases other than Argon.