Creep properties of base metal and welded joint of Hastelloy XR produced for high-temperature engineering test reactor in simulated primary coolant helium

Creep tests of base metal. weld metal and welded joint of Hastelloy XR, whi ch had the same chemical composition as Hastelloy XR produced for an interm ediate heat exchanger of the High-Temperature Engineering Test Reactor, wer e conducted in simulated primary coolant helium. The weld metal and welded joint showed almost equal to or longer rupture time than the base metal of Hastelloy XR at 850 and 900 degrees C, although they gave shorter rupture t ime at 950 degrees C under low stress and at 1,000 degrees C. The welded jo int of Hastelloy SR ruptured at the base metal region at 850 and 900 degree s C. On the other hand, it ruptured at the weld metal region at 950 and 1,0 00 degrees C. The steady-state creep rate of weld metal of Hastelloy SR was lower than that of base metal at 850, 900 and 950 degrees C. The creep rup ture strengths of base metal, weld metal and welded joint of Hastelloy XR o btained in this study were confirmed to be much higher than the design allo wable creep-rupture stress (S-R) of. the Design Allowable Limits below 950 degrees C.