Heat Treatment for Property Enhancement of Wire Arc Additive Manufactured Stainless Steel

Abstract

The influence of the different heat inputs and post-deposited heat treatment on the metallurgical and mechanical properties of the GMAW-based WAAM SS316L was investigated. Epitaxial columnar grain growth was observed along the build direction for all three heat inputs. The fine and coarse vermicular d-ferrite structures were observed in the bottom and middle regions, respectively. The reticular d-ferrite morphology was observed in the top region due to the absence of remelting or reheating. The presence of d-ferrite and s-phases increases with increasing heat input. The higher volume fraction of d-ferrite and s-phases results in an increase in anisotropy in metallurgical and mechanical properties. The post-deposition heat treatment at 1050o C for 15 min dissolves the s-phases and decreases the d-ferritevolumefractionfrom9.35%to2.15%forthelowerheatinputwall.Thecompleteeliminationof s-phases leads to a decrease in Y.S., UTS, and microhardness values.