Low-cycle fatigue crack initiation and propagation from controlled surface imperfections in nuclear steels

Paul Cussac (1) , Catherine Gardin (1) , Véronique Pelosin (1) , Gilbert Hénaff (1) , Laurent de Baglion (2) , Olivier Ancelet (2) , Stéphan Courtin (3)

1 ENDO - ENDOmmagement et durabilité [Institut Pprime]
2 FRAMATOME
3 EDF R&D - EDF R&D

The impact of a controlled surface imperfection on the low-cycle fatigue life in two different steels is investigated. After introduction of a single imperfection with a depth varying from 50 to 350 µm in cylindrical samples, fatigue tests were conducted under fully-reversed total axial strain control in air at ambient temperature. It is shown that the fatigue life is significantly reduced, even in presence of small imperfections. In addition, the use of the potential drop methods provided an assesment of the initiation life and the determination of crack growth rates. Two characteristic crack growth domains were thus identified.

Mots clés: Austenitic stainless steel; Low-alloy steel; Low-cycle fatigue; Surface imperfection; Fatigue life

Domaines: Mécanique des fluides [physics.class-ph]; Matériaux; Matériaux et structures en mécanique [physics.class-ph]

Paul Cussac, Catherine Gardin, Véronique Pelosin, Gilbert Hénaff, Laurent de Baglion, et al.. Low-cycle fatigue crack initiation and propagation from controlled surface imperfections in nuclear steels. International Journal of Fatigue, 2020, 139, pp.105703. ⟨10.1016/j.ijfatigue.2020.105703⟩. ⟨hal-03763434⟩