Effect of heat treatment on the microstructure and corrosion resistance behavior of ENiCrFe-7 weld overlay cladding material

摘要

The effect of heat treatment on the microstructure and corrosion resistance behavior of alloy ENiCrFe-7 had been investigated. The results showed there were more and bigger transgranular niobium carbide with increasing heat treatment time, the effect of heat treatment on (Al-Ti-O)-rich transgranular precipitates was not obvious. Heat treatment promoted formation of the intergranular precipitates. Huey test showed there were more and more severe intergranular corrosion, which resulted from intergranular precipitates, and more serious interdendritic corrosion were induced by niobium carbide precipitated with increasing heat treatment time. (Al-Ti-O)-rich phase was Al2O3 and niobium carbide phase was NbC, the intergranular precipitates consisted of Nb5Si3 and a small amount of Cr23C6, Cr3C2 and Cr7C3 phase. The corrosion product was a mixture of SiO2 amorphous and oxynitride, the microvoid was formed in corrosion product. (C) 2019 Published by Elsevier B.V.