Effect of Reduction in Heat Input on the Behavior of 316LSi Thin Wall Fabricated by Wire Arc Additive Manufacturing

In this work, the effect of heat input reduction on the microstructure and the quality of 316LSi thin walls fabricated by wire arc additive manufacturing was investigated. During the building of the walls, the heat input was reduced from 208.5 to 77.7 J/mm. The interpass temperature increased when using 208.5 J/mm until reaching 650 degrees C and then decreased to remain stable around 600 degrees C for the other heat input levels (101.3, 89.6 and 77.7 J/mm). The study revealed the close dependency of the wall quality on both corrosion resistance and dislocation density values impacted by grain orientation. The x-ray diffraction analysis showed a substantial impact of the (220) and (111) grain orientations on the dislocation density values. A decrease in the dislocation density values accompanied with a tendency toward their isotropic distribution was noticed for a heat input level of 101.3 J/mm. This isotropic distribution was accompanied with an improvement of the corrosion resistance with the best R-p value of 1.49 x 10(4) (Omega.cm(-2)). It was also found that the heat input value of 101.3 J/mm resulted in the best tensile properties of the fabricated walls. The strain hardening behavior analysis revealed that the Hockett-Sherby model gave the best agreement with the experimental tensile data.