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Study of cleavage initiation under thermal shock by tests on cracked rings and thermomechanical calculations



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Titre de la revue : Nuclear Engineering and Design Volume : 236 N° : 10 Pagination : 1049-1060 Date de publication : 01/05/2006

Type de document > *Article de revue

Mots clés > choc thermique, cuve, fissure, interprétation de tests, test

Unité de recherche > IRSN/DSR/SAMS

Auteurs > CHAPULIOT Stéphane, FERRY L., MARIE S., NEDELEC Michel, REYTIER Magali

Date de publication > 01/05/2006


This article describes a new type of test that easily creates a thermal shock combined with mechanical loading by using standard laboratory equipments. The method consists of rapidly heating a ring initially at -175 °C by circulating hot water through judiciously placed holes. It allows to obtain, at minimal cost, data on crack initiation under thermal shock in the transition zone of steel 16MND5 used for pressure vessels, these data being necessary for work on fracture criteria. Details of two tests are given, one with preloading in which cleavage fracture was observed and one without preloading in which cleavage initiation did not occur. The thermomechanical calculations necessary for the interpretation of both tests are also given. Finally, the global approach to fracture is used involving comparison of the loading paths J(T) with the master curves [ASTM E1921-97, 1997. Standard test method for determination of reference temperature to for ferritic steels in the transition range, ASTM standards], as well as the local approach proposed by Beremin [Beremin, F.M., 1983. A local criterion for cleavage fracture of a nuclear pressure vessel steel. Metall. Trans. A 14A, 2777-2287] for estimating the probability of fracture of such rings. It is shown that, in both approaches, the calculated probabilities are consistent with the experimental observations.