1979 Volume 65 Issue 7 Pages 1004-1012
A study has been made of the effect of tungsten, chromium and molybdenum as solution strengthening elements for austenite matrix and yttrium and zirconium as grain-boundary affecting elements on creep rupture properties and weldability of Ni-base alloy which can be used for heat exchanger tube of high temperature gas cooled reactor. The optimum creep rupture strength at 1000°C was obtained in the composition of 18% Cr-15% W-0.5% Mo-Ni. Yttrium and zirconium were found to be beneficial elements to improve the creep rupture strength. The maximum creep rupture strength and good weldability of the alloy were obtained when the amounts of yttrium and zirconium were balanced to the amounts of sulfur and oxygen in the alloy. It suggests that these elements were considered to prevent the segregation of sulfur and oxygen at grain-bondaries.
