Dynamical Fatigue Behavior of Additive Manufactured Products For a Fundamental Life cycle Approach

Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting

“…This implies that for the ZX fatigue behavior, the combined effects of compressive stress and a comparatively larger surface roughness (R a = 4.1 µm; see Table 2 for the roughness values) due to shot-peening are comparable to the much lower surface roughness (R a = 0.66 µm) due to machining. ZX-SP-NSR samples also show a considerably higher fatigue strength compared to ZX-AB samples in the works of Mower and Long [19] and Uhlmann et al [16].…”

“…Therefore, this comparison is not one-to-one and is only included for the sake of showing the trends. Comparison between current (a) ZX and (b) XY fatigue data and corresponding data from the literature [16,19], with details shown in Figure 1.…”

“…This is largely attributed to the large surface roughness of these samples, which results in the opening of surface defects and immature fatigue fracture. Comparison between current (a) ZX and (b) XY fatigue data and corresponding data from the literature [16,19], with details shown in Figure 1.…”

“…Spierings et al [15] observed that the fatigue strength of polished and machined vertically-built (ZX) SS 316L test pieces was similar, while the ZX and as-built (AB) testpieces (ZX-AB), with large a surface roughness (Ra ≈ 10 µm), exhibited an inferior fatigue strength compared to the polished and machined testpieces. Uhlmann et al [16] studied the fatigue behavior of stainless steel (SS) 316L ZX test pieces with the three different surface conditions of AB, vibratory-finished, and machined (turned). They showed that test pieces with machined surfaces displayed the best fatigue performance, followed by vibratory-finished pieces, and AB test pieces showed the most inferior fatigue behavior.…”

“…However, the effect of SP on the fatigue behavior of AM parts has not been reported much in the literature. Researchers have studied force-controlled fatigue tests using tension or rotating methods for steels, such as SS 17-4PH [19,24,25], SS 15-5PH [15][16][17][18], and SS 316L [15][16][17][18][19], produced using different laser systems such as EOS M270, Concept Laser M1, etc. There are also limited strain-controlled fatigue analyses of laser-printed steel in the literature [26,27].…”