부산대학교 도서관

A Fe-based filler material with the composition of Fe-20Ni-5Co-2.5Mn-0.2C was used for welding9% Ni steel, and the effect of post-weld heat treatment on the microstructure and mechanical properties ofthe welded joints was investigated. Post-weld heat treatment of the welded joint was performed in thetemperature range of 200 to 600 oC. After the experimental selection, the microstructure changes of the weldmetal and base metal were investigated in detail at heat treatment temperatures of 350 and 600 oC. Grainmorphology, size, and the location of precipitated cementite were studied using SEM and EBSD phase maps. The mechanical properties of the weld joint were characterized by tensile properties and micro-hardness. Based on the experimental results, this study provides key insights into the applicability of post-weld heattreatment to weld joints of 9% Ni steel prepared using Fe-based filler material to improve the mechanicalproperties, toughness and ductility of the weld joints.