27th IFHTSE CONGRESS & EUROPEAN CONFERENCE ON HEAT TREATMENT 2022

The aim of this work is to investigate the behavior of “as-build” (produced by additive manufacturing, 3D printed) maraging steel in simultaneous surface coating and aging process. In the frame of the study coating experiments on maraging M1 grade steel substrate were carried out. The “as-build” maraging steel parts were produced by selective laser melting (SLM) technology. The “as-build” 3D printed and the reference (Böhler W720, solution treated) specimens were surface coated by the same surface modification technologies. The applied coating heat treatment technology consisted of two steps. First, a nitrided layer was produced on the surface of the specimens. The temperature and the duration of nitriding step were defined on the basis of ageing properties of the maraging steel determined by DSC measurements. In this stage of the heat treatment the diffusion of nitrogen and the precipitation hardening of the maraging steel are the main processes, which happen at the same time, simultaneously. The second, upper layer of the coating was produced at a lower temperature by the physical vapor deposition (PVD) method (DLC, CrN, TiN) in a thickness less than 10 microns. “As-build” and reference material specimens were heat treated under industrial circumstances and were investigated in a comparative manner from the point of view of surface layer structure and surface hardness.