Effect of build orientation on wear and erosion behavior of maraging steel processed by powder bed fusion using laser beam (PBF-LB)

Abstract

Abstract The wear and erosion behavior of additively manufactured maraging steel with built orientations of 0°, 45° and 90° were investigated and compared with conventional (cast and hot rolled) samples. To investigate the effect of heat treatment, processed samples were subjected to solution treatment and ageing. As-built (AB) and heat-treated (HT) samples were wear-tested at various loads of 20N, 40N and 80N, at constant disc speed and specific sliding distance. Erosion tests were performed at 90° impingement angle for 40 min with erosion discharge rate of 4.5 g min−1, wear rate was found increasing with the increase in load from 20N to 80 N, and was found affected by build orientation, mainly in the as-built additive samples. In both, as built as well heat-treated conditions, 90° oriented samples were found more wear-resistant. However, wear resistance of the heat-treated samples was observed to be relatively higher as compared to that of as-built samples. Coefficient of friction (COF) decreased with increase in load, in both as built as well heat-treated conditions. Erosion resistance of the as-built (AB) and heat-treated (HT) samples in 0° orientation was higher than that of other build orientations. Prior to heat treatment, erosion resistance of the conventional samples was inferior to that of additive samples, due to comparatively coarser microstructure; however, after the heat treatment, erosion resistance was increased. Worn and eroded samples were examined under SEM and AFM. At low load of 20 N, abrasive wear by ploughing and at high load of 80N, adhesive wear was noticed. Erosion occurred mainly by lip formation and plastic deformation.