Investigating Heat Transfer Strategies for Geometrical Accuracy and Solidification Behavior of Additively Manufactured SS316L Thin Clad Structures

The present study investigates the impact of different heat transfer approaches on the precision of geometry and solidification behavior in additively manufactured thin clad walls. Employing a 2D laser scanner to assess dimensional accuracy, the study demonstrates that thin clad walls produced on a copper base plate with forced air convection exhibit notably superior accuracy compared to those on a mild steel substrate with natural convection. Microstructure analysis unveils distinct characteristics: Thin clad walls printed with natural convection on mild steel display a coarse columnar dendritic structure marked by increasing primary dendrite arm spacing (PDAS) from bottom to top (10.4 ± 0.7 to 14.5 ± 3 µm). In contrast, forced convection leads to a fine cellular and columnar dendritic microstructure with minor PDAS variation (4.6 ± 0.9 to 7.4 ± 1.7 µm) along the entire vertical span.