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Fractographic and microstructural aspects of fracture toughness testing in irradiated 304 stainless steel

Conference ·
OSTI ID:6017598

Fracture toughness and Charpy impact test results on 304 stainless steel baseplate, weld and heat-affected zone (HAZ) tested at 25/sup 0/C and 125/sup 0/C are correlated with the microstructural and fractographic features observed in these materials. Specimens were collected from several sections of 12.7 mm (0.5 in.) wall thickness piping removed from a process system, and were characterized by different material chemistries and thermomechanical histories. As a result, mechanical properties vary over a considerable range from one pipe section to another. The presence of delta ferrite in some of the samples caused significant degradations in the toughness properties for certain crack orientations. Decreases in Charpy impact energies occur in the same material for different crack orientations. Materials irradiated showed 40% decreases in Charpy impact energy, but little change in fracture morphology. An increase in the test temperature resulted in an expected increase in Charpy energies for all materials. Fractographic features did not change appreciably with respect to the 100/sup 0/C increase in test temperature. In unirradiated specimens, a test temperature increase caused lower J/sub Ic/ and J-R curve values with tearing modules values increased. The latter is due to the large decreases in tensile strength with increasing test temperature. The weld metals tend to have the highest tearing resistance, while the HAZ's tend to have the lowest. 30 figs., 3 tabs.

Research Organization:
Materials Engineering Associates, Inc., Lanham, MD (USA); Savannah River Lab., Aiken, SC (USA)
DOE Contract Number:
AC09-76SR00001
OSTI ID:
6017598
Report Number(s):
DP-MS-87-91; CONF-871207-19; MEA-2245; ON: DE88000795
Country of Publication:
United States
Language:
English