Examining hatch spacing variations: Impacts on SS316L microstructure and mechanical performance in laser-wire directed energy deposition

While hatch spacing effects have been extensively studied in powder-based additive manufacturing, their influence in laser wire directed energy deposition (LW-DED) remains underexplored. In metal additive manufacturing, grains tend to grow epitaxially along the build direction, affecting the texture and mechanical properties of the manufactured parts. This study addresses this challenge by systematically investigating hatch spacing as a process lever for tailoring texture and grain refinement in SS316L components. Controlling the microstructure will allow application-based optimization of the mechanical properties in specific locations of the manufactured components. We found that decreasing hatch spacing disrupts the columnar grain growth in the melt pool. Increasing the hatch spacing results in shallower melt pools, promoting epitaxial grain growth. Larger hatch spacing promoted <001> ∥ BD and coarse columnar grains, whereas reducing hatch spacing disrupted columnar growth, refined grains by 41%, and promoted <101> ∥ BD orientations. Despite these microstructural changes, tensile properties along the build direction were only modestly affected. The 1.0 mm spacing provided the best compromise, achieving 12% higher UTS and 3% higher YS than the lowest performing case, while avoiding porosity linked to in-situ process control that influences wire feed and energy density. These results demonstrate hatch spacing as a practical tool for tailoring texture and grain refinement in LW-DED, offering industrial guidance for improving properties of SS316L components where both mechanical reliability and microstructural control are critical. • Hatch spacing effect in laser wire directed energy deposition of SS316L was studied. • The microstructure of the samples was investigated using SEM, EBSD, and OM. • Mechanism behind grain refinement using this strategy was explained. • Effect of the system's process control feature was examined. • Impact on mechanical properties was studied.