Effect of dwelling time in VIM furnace on chemical composition and mechanical properties of a Ni–Fe–Cr alloy

The mechanical properties and changes in chemical compositions and microstructure of a Ni–Fe–Cr alloy in different dwelling time in a vacuum induction melting (VIM) furnace were studied. The chemical analysis shows that the dissipations of Al, Ti and Si increase with increasing the dwelling time in the VIM furnace. With the decrease in Si content due to increasing the dwelling time in the VIM furnace, the segregation of niobium is reduced, resulting in lower incoherent δ phase in the grain boundaries. This incoherent δ phase promotes intergranular fracture in the specimen with the lowest dwelling time. The dissipations of Al and Ti with increasing the dwelling time in the VIM furnace lead to decrease the hardness, yield and ultimate tensile strengths of the alloy, while the elongation increases owing to the lower number of inclusions and strengthening phase (γ″).