Session: MF-06-02 Materials and Technologies for Nuclear Power Plants II

Paper Number: 62044

Start Time: Tuesday, July 13, 2021, 08:00 PM

62044 - Creep Data Acquisition in Heat Affected Zone of 9-12% Cr Csef Steels With Specially Designed Experiments 

Premature creep failure of welded 9-12%Cr creep strength enhanced ferritic (CSEF) steel steam components caused by creep strength degradation in the heat affected zone (HAZ) poses many challenges for operation and maintenance of modern advanced power plants. High temperature creep properties of local HAZ regions are essential for residual lifetime assessment of those welded components. However, these localized creep data in the HAZ cannot be directly measured with standard creep testing methods due to the high microstructure heterogeneity and the limited size of the HAZ. To overcome this challenge, we developed and integrated a series of specially designed experiments, including a finite element model–assisted Gleeble simulation, high-temperature creep testing with in-situ strain distribution measurement by digital image correlation (DIC), and high-resolution electron microscopy analysis. With a customized HAZ specimen produced by the unique Gleeble simulation, the spatial resolution of in-situ DIC strain measurements on HAZ was significantly improved. High resolution creep data of individual coarse grained HAZ, fine grained HAZ, and intercritical HAZ in a single HAZ specimen was directly measured using the DIC. A connection between the measured creep properties and underlying microstructures was also built to further understand those premature creep failures. This established Gleeble-Creep-DIC technique can easily be adapted to test other high-temperature alloy welds used in advanced power plants.

Presenting Author: Yiyu Wang Oak Ridge National Laboratory

Authors:

Yiyu Wang Oak Ridge National Laboratory
Wei Zhang Oak Ridge National Laboratory
Hui Huang Oak Ridge National Laboratory
Yanli Wang Oak Ridge National Laboratory
Jian Chen Oak Ridge National Laboratory
Zhili Feng Oak Ridge National Laboratory