Evaluation of Pipe Fracture Characteristics for SA312 TP304L Stainless Steel

In order to perform elastic-plastic fracture mechanical analyses, fracture resistance curves for concerned materials are required. A standard CT specimen was used to obtain fracture resistance curves. However the fracture resistance curve by the standard CT specimen was very conservative to evaluate the integrity of the structure. Also the fracture resistance curve was affected by the specimen geometry, crack plane orientation, reverse cyclic loading and dynamic strain aging. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the standard CT specimen. For these purpose, fracture tests using the real-scale pipe specimen and standard CT specimen test were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method was used to measure the crack extension and the length for the pipe test. From the result of the pipe and the standard CT specimen tests, it was observed that the fracture resistance curve of the standard CT specimen test was conservative compare to that of the pipe specimen test.