Wear Behavior of Conventionally and Directly Aged Maraging 18Ni-300 Steel Produced by Laser Powder Bed Fusion.

This study aims to explore the wear performance of maraging 18Ni-300 steel, fabricated via laser powder bed fusion (LPBF). The building direction dependence of wear resistance was investigated with various wear loads and in terms of ball-on-disk wear tests. The effect of direct aging heat treatment, i.e., aging without solution heat treatment, on the wear performance was investigated by comparing the wear rates of directly aged samples, followed by solution heat treatment. The effect of counterpart material on the wear performance of the maraging steel was studied using two counterpart materials of bearing steel and ZrO balls. When the bearing steel ball was used as the counterpart material, both the as-built and heat-treated maraging steel produced by the LPBF showed pronounced building direction dependence on their wear performance when the applied wear load was sufficiently high. However, when the ZrO ball was used as the counterpart material, isotropic wear resistance was reported. The maraging steel produced by the LPBF demonstrated excellent wear resistance, particularly when it was aging heat-treated and the counterpart material was ZrO. The directly aged sample showed wear performance almost the same as the sample solution heat-treated and then aged, indicating that direct aging can be used as an alternative post heat treatment for tribological applications of the maraging steels produced by LPBF.