Building-Direction Dependence of Wear Resistance of Selective Laser Melted AISI 316L Stainless Steel Under Quasi-stationary Condition

Corrosion Resistance of Laser Powder Bed Fused AISI 316L Stainless Steel and Effect of Direct Annealing

“…These results indicate that the anisotropy in corrosion resistance by the laser scan direction during the PBF process is insignificant, while the mechanical properties show anisotropy according to the morphology and arrangement of the melt pool, which are determined by the laser scan direction [23,24,[37][38][39]. The SS316L printed in one direction through the PBF process has a different arrangement of the melt pool and a different microstructure due to the laser scan direction, and thus, has mechanical anisotropy according to the building direction of the material [23,24,36,37]. The SS316L alloy is very important in applications for corrosion resistance as well as mechanical properties; so, it is necessary to evaluate it compared with the cold-rolled SS316L.…”

“…Therefore, it can be seen that the SLM-produced SS316L with sub-grain cell generated by rapid solidification has the same crystal structure as cold-rolled SS316L. The SS316L printed in one direction through the PBF process has a different arrangement of the melt pool and a different microstructure due to the laser scan direction, and thus, has mechanical anisotropy according to the building direction of the material [23,24,36,37]. The SS316L alloy is very important in applications for corrosion resistance as well as mechanical properties; so, it is necessary to evaluate it compared with the coldrolled SS316L.…”

“…Even though such fine sub-grain cells disappear by post heat-treatment, the XRD pattern consists of austenite and alpha phase, and there were no phase changes by heat treatment (Figure 2f). Meanwhile, the CR sample has a smaller grain size than that of the SLMed SS316L (Figure 2e) [24], and the XRD pattern also consists of austenite and alpha phases. Therefore, it can be seen that the SLM-produced SS316L with sub-grain cell generated by rapid solidification has the same crystal structure as cold-rolled SS316L.…”

“…A so-called 90 • rotate scanning strategy was used, i.e., the laser scanning lines are tilted by 90 • between each layer. Further details of the material, including the microstructure, tensile property, and wear behavior relative to the building direction, were reported previously by a few of the present authors in [17,23,24,28]. To evaluate the corrosion property of the SLMed SS316L samples, two types of specimens were built in different directions relative to the building orientation.…”

“…They concluded that optimizing the SLM process parameters showed superior ultimate tensile strength and elongation compared with SS316L alloys manufactured by traditional casting processes. Lee et al [23,24] investigated the microstructure, tensile properties, and wear properties of SS316L produced by the SLM process according to the building direction. The tensile property and wear resistance are changed by the melt-pool boundary generated during the process and a sub-grain cell with a size of 1 µm or less, and it was reported that the alloy manufactured by the SLM process has similar mechanical properties compared with the cold-rolled material.…”