Modifying of mechanical properties in the deposited metal prepared by welding wire containing nanosized oxide particles

Abstract

Fine oxide particles can play a role in refining grains and promoting nucleation in steel. In this research, a solid welding wire containing nanosized oxides was obtained by preparing a ‘master alloy’. The oxide size was studied by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that micron-sized oxides were crushed into nanosized particles under thermal shock in the welding wire steel smelting process. The mechanical properties of deposited metals were studied by tensile and Charpy impact tests. The results demonstrate that the low-temperature impact toughness of deposited metal is effectively improved by adding oxides to wires. When the oxide content was 1%, the impact absorbed energy was 59 J at −40 °C. Compared with that of the deposited metal without oxides, the impact absorbed energy increased by 22.92%. The addition of oxides refines the original austenite grains and promotes acicular ferrite nucleation so that the deposited metal has better mechanical properties. To obtain good strength toughness matching, the welding wire with 1% oxides has the best comprehensive properties.