Sensitivity of direct metal laser sintering Maraging steel fatigue strength to build orientation and allowance for machining

This work deals with the effect of build orientation and of allowance formachining on DMLS‐produced Maraging Steel MS1. The experimental results,arranged by tools of Design of Experiment, have been statistically processedand compared. The outcomes were that, probably due to effect of the thermaltreatment, machining, and material properties, the aforementioned factors donot have a significant impact on the fatigue response. This made it possibleto work out a global curve that accounts for all the results, consisting in a highamount of data points. This can be regarded as one of the most complete andreliable fatigue models in the current literature. Fractographic and micro-graphic studies have been performed as well, to individuate the crack initiationpoints, usually located at subsurface porosities, and to investigate the locationof internal inclusions and the actual martensitic microstructure along thestacking direction and on the build plane.