Influence of shielding gas mixtures on mechanical properties of AISI 316L stainless steel structure fabricated through wire-arc additive manufacturing

Abstract

Wire arc additive manufacturing (WAAM) process offers a promising technique for producing large metallic parts and complex structures due to its high deposition rate and low cost. This study examined the influence of various shielding gas mixtures of Argon (Ar) and Carbon dioxide (CO2) on the properties of 316L stainless steel fabricated via cold metal transfer-WAAM process. The various shielding gas mixtures include: 100% Ar, 95% Ar + 5% CO2, 90% Ar + 10% CO2, and 80% Ar + 20% CO2. Microstructure of the deposited wall consisting of dominant columnar grains with lathy and skeletal δ morphologies in austenite matrix. XRD analysis confirmed the presence of austenite (γ) and ferrite (δ) phases with various peak intensities. Micro-hardness demonstrated an increase in CO2 (10%) content, leading to increased hardness, with values varied between 186.52 HV and 195.28 HV. Tensile strength increases as CO2 increases; the UTS values from 453.46 MPa–454.07 MPa, while YS values 318.22 MPa–319.48 MPa and confirmed the anisotropy in nature. Fracture studies indicate the uniform distribution of dimples with micro-void coalescence and exhibit ductile fracture. This study highlights the importance of various shielding gas mixtures and producing high-performance AISI 316L stainless steel components with beneficial mechanical properties for advanced engineering applications.