Thermal creep-fatigue failure test of SUS316FR piping specimen containing circumferential weldment; (2) Elastic analysis and damage evaluation

not registered; Wakai, Takashi ; not registered; not registered; not registered; not registered

This report describes elastic thermal stress analysis and creep-fatiguedamage evaluation results of an SUS316FR piping specimen which contains circumferential weldment in the middle portion of it. Thermal creep-fatigue failure test on the specimen was conducted in a sodiumtest loop named STST to clarify creep-fatigue crack initiation behavior of SUS316FR base metal and weldment under thermal bending stress conditions, which is caused by temperature gradient arisen in the wall thickness or the specimen. Thermal transient test was conducted under the condition that 550C and 300C sodium alternately flow into the specimen for 5 hours and 1 hour, respectively in one cycle. The test had been completed after loading 1,600 cycles or thermal transients. After the test, crack inspection by PT was performed, and cracks were observed successfully in both the base metal and weldment. For an analytical study, heat transfer analysis using measured temperature data and elastic thermal stress analysis were carried out with the finite element method, and the analysis results were utilized to develop a candidate creep-fatigue damage evaluation method for SUS316FR steel based on elasticanalysis. Some analysis results and damage evaluation results of the specimen arepresented here, and crack initiation after 1,600 cycles of thermal transients is predicted based on the calculated creep-fatigue damage, which demonstrates a good agreements with the crack distribution on the specimen inner surface.