Superalloys and the Development of Advanced Ultra-supercritical Power Plants

摘要

A 700°C advanced ultra-supercritical (A-USC) power plant technology project was initiated in China in the year of 2011. The highest temperature components in A-USC boiler are superheater and reheater tubes. The fire-side metal temperature can reach 750°C (even higher). Based on the very long time service(30-40 years) these important high temperature tubes require 10~5h long time stress rupture strength higher than 100MPa and the corrosion/oxidation layer loss less than 2mm for 2×10~5h. The highest temperature components in 700°C steam turbine are the buckets of different stages and require very long service time. At this severe condition only superalloys can fulfill these unusual requirements. This paper reviewed Fe-Ni and Ni-base superalloys from the view point of structure stability and long term mechanical properties and corrosion/oxidation resistance for 700°C A-USC power plant materials selection.