Microstructure, strength, and fiber texture evolutions in arc-based casting using low-carbon steel wire

Abstract

The present investigation introduced a modified casting route for steel component manufacturing that uses an electric arc to melt the filler wire and transfer the molten metals as tiny droplets into the sand mould. To study the influence of heat input on microstructure, phase percentage, interlamellar spacing, tensile properties, wear resistance, residual stress, and texture fiber evolutions, samples are cast on a wide range of wire feed speed (WFS) (3 to 9 m/min). It has been observed that higher WFS increases the heat input that transfers small-sized molten droplets into the mould cavity at a faster rate and suitably reduces the mould filling time. Heat input shows a positive response with the microstructural evolutions, i.e., large-sized grains with increased pearlite concentration and interlamellar spacing are encountered under high heat input (low cooling rate). It is attributed to improved carbon atom diffusion with the ferrite phase and increased pearlite transformation time. This increment in pearlite concentration and compressive residual stress further enhanced the tensile performances. Wear resistance varies inversely with the heat input rate. A confirmation of the oxide layer formation due to frictional heat generation during wear testing has been authenticated from Raman spectroscopy analysis. Due to its drop-by-drop deposition nature, high WFS raises the heating rate and droplet detachment frequency. Hence, the degree of recrystallisation increases that boost up ϒ-fiber development with intensified θ-fiber components like {001}〈110〉 and {001}〈100〉. Due to the controlled metal transfer under plasma and argon gas shielding, the casted sample has fewer chances of porosity.