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Title: Design and Scoping Tests on Alloy 617 Using Notched Specimen Geometry to Validate Methods for Multiaxial Stress Relaxation

Technical Report ·
DOI:https://doi.org/10.2172/1995711· OSTI ID:1995711
ORCiD logo [1];  [2]
  1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Imtech Corporation, Knoxville, TN (United States)

In FY 2022, a development effort was initiated at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) to examine the multiaxial stress-relaxation behavior and multiaxial stress-state effect on the creep-fatigue (CF) performance for Alloy 617 at elevated temperatures. This effort supported the development of the design rules in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC), Section III, Division 5. In this work, two types of the notch specimen geometries were designed. An inelastic constitutive model was used to investigate the stress triaxiality and elastic follow-up effects on the notch specimens under CF deformation in the finite element (FE) simulations. The numerical study demonstrated that the stress triaxiality and elastic follow-up caused by the notches both play significant roles in the stress-relaxation behavior. In addition, Alloy 617 CF experiments were designed, and the testing on the notch specimens is ongoing. CF test failure data will be generated on the specimens with notches under various conditions in FY 2023, and the results will be used to validate methods for accounting for the multiaxial stress relaxation effect in the design code.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Nuclear Energy (NE), Reactor Fleet and Advanced Reactor Development. Office of Nuclear Reactor Deployment
DOE Contract Number:
AC05-00OR22725
OSTI ID:
1995711
Report Number(s):
ORNL/TM-2022/2675
Country of Publication:
United States
Language:
English