Abstract
Tensile tests were conducted at room and high temperature to clarify the fracture strength and crack coalescence behavior of multiple cracks in SUS304 flat plates. The shape of the specimen is a plate, and electrical discharge machined (EDM) notches were introduced on both sides of the central smooth part. Then, a fatigue pre-crack was generated at the tip of the notch. The position of the crack was expressed by the distance between the crack surfaces and the distance between the crack tips. As a result of the tensile test at room temperature, when the distance between the crack surfaces was shorter than about 8 mm, the cracks coalesced. On the other hand, when the distance between the crack surfaces was about 10 mm, no crack coalescence was observed, and there was a change point in the crack coalescence behavior. As a result of the high temperature test, crack coalescence was observed when the distance between the crack planes was about 8 mm, but the change point of the crack coalescence behavior is unknown because there is no data. It was found that the change points of the coalescence behavior of the cracks obtained in the experiment satisfy codes for nuclear power generation facilities (JSME S NA1-2019).
