Microsegregation and homogenization of nickel base corrosion resistant alloy C-276 ingots

The microstructure and microsegregation of nickel base corrosion resistant alloy C-276 vacuum-induction-melting and electroslag-remelting ingots were studied by optical microscope, scanning electron microscopy and energy dispersive X-ray spectroscopy. Based on the calculated results of the residual segregation parameter model, four homogenizing treatments were tested. Microstructure analysis and thermal compression test with a Gleeble 1500 machine were used to verify the effect of homogenizing treatment. The results show that the severest segregated elements in C-276 is Mo, and 1170℃/20h is the most appropriate treatment for C-276 alloy in the study as it ensures homogenizing effect and reasonable grain size for optimizing the hot-working plasticity of the alloy. It is also proved that homogenization process of C-276 alloy can be effectively predicted and evaluated by the residual segregation parameter model, which basically agrees with the experimental results.