Evaluation of the Materials Technology Required for a 760ºC by haj90599


									        Evaluation of the Materials Technology Required for a 760ºC Power Steam Boiler

                             John P. Shingledecker and Ian G. Wright

                                  Oak Ridge National Laboratory
                                      Oak Ridge, TN, USA

The U.S. Ultra-supercritical (USC) Steam Boiler Consortium, funded by the U.S. Department of
Energy and the Ohio Coal Development Office, has been working for five years to develop the
necessary materials technology to construct a steam power boiler with final steam conditions of
760ºC and 35MPa. One large component of this work is to evaluate the properties of the
materials chosen for such a boiler. While long-term creep strength of base metal is initially used
to set temperatures, stresses, and simple design rules, it is clear from in-plant experience that the
limiting material strength factors are not always directly related to base-material strength. Rather,
fabrication variables (including weldment properties and cold work effects), component behavior
(as manifested in multi-axial creep deformation), and operational issues (including large thermal
transients induced during emergency shutdown procedures) all must be considered in evaluating
the materials technology for a new high-temperature plant. Much of the understanding of these
issues has been gained through in-plant usage of ferrite steels. However, little knowledge exists
for in-plant usage of nickel-based superalloys. With this in mind, an extensive effort is being
made at the Oak Ridge National Laboratory (ORNL) to evaluate the materials technology being
developed in the U.S. USC steam boiler program. This poster illustrates the progress of this
work, which includes: long-term creep testing; pressurized creep testing of tube bends to evaluate
cold-work effects; weldment creep tests in various geometries to evaluate welds and potential
design issues; notched bar and pressurized creep tests for evaluating multiaxial creep effects; and
thermal shock testing to evaluate materials resistance to large thermal transients. In addition to
the diverse mechanical testing being performed, ORNL also is using computational modeling,
electron microscopy studies, and more advanced tools (including synchrotron radiation) to better
understand fundamental materials issues, and to provide guidance to the
 consortium’s efforts.
Research sponsored by the Office of Coal and Power R&D, Office of Fossil Energy, U. S.
Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

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