Impact toughness of components made by GMAW based additive manufacturing

Abstract

Additive manufacturing of metals is an innovative near-net-shaped manufacturing technology used for producing final solid objects by depositing successive layers of material melted in powder or wire form using a focused heat source directed from an electron beam, laser beam, or plasma or electric arc. Wire arc additive manufacturing (WAAM) techniques, although have lesser precision as compared to laser or electron beam techniques but have the advantage of lower cost and lesser time required. In this research, gas metal arc welding (GMAW) process has been used using AWS ER70S-6 electrode wire to create a multi-layer single pass structure after controlling the parameters including current, voltage and travel speed so that uniform height is attained throughout the weld bead. The resulting material may have different directional mechanical properties because of factors including different penetration properties and bonding strength and also preheating and post-heating effects of successive layers. This study focuses on the impact toughness of the resulting material. Charpy impact test is carried out on the samples taken in both along the direction of deposition and in the direction perpendicular to it to analyze the impact toughness in different directions. To further investigate the behavior of the structure, Brinell hardness, metallography and fractography have been performed. The results show that material has high impact toughness with very ductile behavior.