Mechanical, corrosion and tribocorrosion resistance of additively manufactured Maraging C300 steel

This article presents the effect of selected parameters of the additive manufacturing process on the structure of Maraging C300 steel and consequently on its properties: hardness and resistance to abrasive wear, corrosion and tribocorrosion in 3.5% NaCl. The samples were produced with laser beams of 300, 350 and 400 W. Materials with different average microhardnesses of 436, 374 and 315 HV0.05 have been manufactured, respectively. Comparative evaluation of wear resistance on a ball-on-plate model node bench was carried out. Tests were performed under tribocorrosion conditions and for only mechanical forcing. Corrosion resistance was estimated from polarization curves. The article summarizes tribocorrosion model for Maraging C300 steel, which takes into account the effect of grain size on the course of elementary wear processes, especially on the formation of friction and corrosion synergy. The results show that reducing the power of the laser beam in the manufacturing process of Maraging steel produces a material with a more fine-grained structure. Smaller grains provide higher hardness and greater resistance to abrasive wear. Unfortunately, at the same time, the corrosion resistance in 3.5% NaCl is worse. The different effect of grain size on abrasion intensity and corrosion wear means that under tribocorrosion conditions, increasing microhardness does not reduce volumetric wear. The least tribocorrosion wear is provided by the material produced by a 350 W laser beam, amounting to 1.34 ×10-3 mm3.