Fracture resistance of cracked duplex stainless steel elbows under bending with or without internal pressure

Electricite De France (EDF), in co-operation with Framatome, has conducted a large research programme on the fracture behaviour of aged cast duplex stainless steel elbows. One important task of this programme consisted of testing three large diameter (580 mm O.D.) thermally aged cast elbows containing either one or two semi-elliptical notches on the outer surface of the flank. The first two elbow tests (called SEMI and SEM2) were conducted under in-plane closure bending at 320°C and the third one (called SEM3) under constant internal pressure and in-plane closure bending at 60°C. Those tests were carried out with 2/3-scale models of PWR primary loop elbows. This paper presents the results of the experiments and the results of the fracture mechanics analyses, based on finite element calculations.