1990

Keinänen, Heikki; Rintamaa, Rauno; Öberg, Tero; Sarkimo, Matti; Saarenheimo, Arja; Talja, Heli

Within the Nordic countries a four-year research programme in the area of elastic-plastic fracture mechanics was initiated in 1985. Seven laboratories from Denmark, Finland, Norway and Sweden are participating in the programme. The main technical objective of the programme is to clarify how catastrophic fracture can be prevented in pressure vessels and piping by using the leak-before-break concept. The major experimental effort of the programme is destructive pressurisation of a large size pressure vessel up to rupture. The vessel has dimensions similar to a nuclear reactor pressure vessel, and it has been in operation for 20 years in a Finnish oil refinery plant. The materials characterisation of the vessel has been partially carried out within an extensive Nordic round-robin programme. Two pressure tests have been carried out. In both tests an artificial sharp axial surface flaw was made on the inner wall of the vessel. The experimental details of the last test including repair welding of the vessel, flaw preparation, instrumentation and material characterisation are described in this report. The fracture behaviour as well as experimental results are reported. The failure pressure is compared to estimates of the analytical pre-test calculations.