Investigation of structure and properties of low alloy steel obtained by wire arc additive manufacturing under various fluxes

Abstract

Wire arc additive manufacturing (WAAM) is vigorously explicating direction of mechanical engineering. When using submerged arc welding (SAW) it is possible to apply low-alloy steels with high efficiency and properties, that will allow to use it for manufacture of details and instrument. Microstructure, hardness, distribution of nonmetallic and chemical composition were investigated for SAW build up walls, in as-deposited condition, by low-alloy wire under fluxes with a different basicity. The characteristics of microstructure fixed by an optical microscopic metallography remain practically constant for all deposited weld metals. It is ferrite - martensite (bainite) structure, which has a high dispersibility. The exploration of hardness has shown formation of the partially quenched top with increased hardness and previous thermo- cyclic treated passes with lower hardness. When depositing SAW insignificant saturation of metal with silicium and manganese and a carbon drop occurs. The distribution of nonmetallics is most favorable for additive manufactured material under neutral and basic fluxes. As a result, a comparative research of fluxes was conducted, allowing to make a choice for additive manufacturing of low-alloy work pieces.