Design and performance of weld filler metal to match an advanced heat-resistant Fe-Cr-Ni alloy

In the present study, a novel welding filler metal with alloying system of Fe-22.5Cr-25Ni-2Mn-0.45Si-1.5Co-3.8W-3Cu-0.5Nb-0.2N-C-B was manufactured to match an advanced heat-resistant alloy Sanicro 25. The corresponding all-weld-metal deposits were prepared to carry out microstructure and mechanical properties inspection with compared to Sanicro 25. Elemental redistribution occurs in interfaces between intermediate layer and deposited metal, which has an influence on toughness and microhardness. The filler metal presents superior strengths than Sanicro 25, which was checked by comparatively calculating the yield tensile stress. Transmission electron microscope observation verified the existence of nano-sized precipitation in the deposit after high-temperature tests. Moreover, the quantitative fractography analysis were conducted over the ruptured specimens after tensile tests, which confirms the influence of element boron on eradicating the coarse intergranular carbides.