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Analytical prediction of the location of ductility dip cracking in the trans-varestraint test

Conference ·
OSTI ID:471449

Some NiCrFe weld metals exhibit decreased ductility over a temperature range known as the {open_quotes}ductility dip{close_quotes} temperature (DDT) range. Ductility dip cracking (DDT) is a phenomenon which occurs in a zone bounded by the DDT range on its sides and a threshold plastic strain on its bottom as shown in figure 1. Figure 1 illustrates how ductility varies as weld metal cools from the solidus temperature for materials with and without a ductility dip. The purpose of this work is to demonstrate the ability to predict the location of the DDC in a Trans-Varestraint Test (TVT) for a specimen machined from a weld deposited EN52 plate. The DDC predictions require a combination of Trans-Varestraint testing and finite element analysis. The test provides the threshold value of externally applied nominal strain below which DDC does not occur. The analysis provides the corresponding threshold local or peak strain. The threshold local plastic strain level and the DDT range are used to predict the location of the DDC. The ultimate purpose of this work is to evaluate susceptibility of highly constrained, component welds to DDC. Test results for Trans-Varestraint Testing for a weld deposited EN52 plate are reported in reference. The ability to predict the location of the DDC in the Trans-Varestraint Test using the techniques reported herein is demonstrated by showing good comparison between the analytical results and the test data.

Research Organization:
Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.
Sponsoring Organization:
USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
DOE Contract Number:
AC11-93PN38195
OSTI ID:
471449
Report Number(s):
WAPD-T--3135; CONF-970691--1; ON: DE97004870
Country of Publication:
United States
Language:
English