Fracture toughness of irradiated Type 304 stainless steel

Technical Report · Mon Aug 08 04:00:00 EDT 1988

OSTI ID:6728169

Caskey, Jr, G R; Louthan, Jr, M R

Experimental evaluation of the elastic-plastic fracture behavior of a Type 304 stainless steel sample irradiated to 1.9 displacements per atom (dpa) provided a J-integral value of 74kJ/m/sup 2/ for the beginning of stable, mechanically induced crack growth is about 1.4. The experimental measurements of the fracture resistance of a steel similar to that used in the SRP reactors demonstrate a safety factor in the fracture analysis of the reactor tanks. The lowest measured toughness was found in a specimen taken from the heat affected zone of a circumferential weld. The sample was oriented so that crack growth was essentially parallel to the principal direction of plastic deformation of the steel during fabrication. Because these toughness values were lower than any of the other experimental determinations of J/sub IC/ values for the irradiated stainless steel, an analysis for metallurgical causes of the low toughness was made. Metallographic examination of samples from the pipe section showed ferrite stringers and inclusions are aligned in the primary direction of plastic deformation during fabrication of the rolled plate used to form the pipe. Aligned defects are also known to lower the fracture resistance when crack growth is in the direction of alignment. The metallographic observations are thus consistent with the measured low toughness when crack growth was along the pipe axis and parallel to the aligned defects. Because the rolled plate used to fabricate the SRP reactor tanks should have a microstructure similar to the plate used to manufacture the pipe, the mechanical property-microstructure data evaluated in this memorandum and summarized in Reference 1 is considered applicable to the reactor tanks as well as the process water piping. 9 refs., 4 figs., 1 tab.

• Research Organization: Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.
• DOE Contract Number: AC09-76SR00001
• OSTI ID: 6728169
• Report Number(s): DPST-88-719; ON: DE89001644
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRACKS
CRYSTAL STRUCTURE
FRACTURE MECHANICS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MECHANICS
MICROSTRUCTURE
NATIONAL ORGANIZATIONS
NICKEL ALLOYS
PIPES
PRODUCTION REACTORS
RADIATION EFFECTS
REACTORS
SAVANNAH RIVER PLANT
STAINLESS STEEL-304
STAINLESS STEELS
STEELS
US AEC
US DOE
US ERDA
US ORGANIZATIONS