Lifetime evaluation of a steam pipeline using NDE methods
Ocena preostale trajnostne dobe parovoda z uporabo neporušitvenih preiskav (NDE)

english

2011

volume 45, issue 4

Inštitut za kovinske materiale in tehnologije
(Obvezni izvod spletne publikacije)

Before its shutdown, the steam pipeline made from X20CrMoV121 steel in the Power Plant Toplarna - Ljubljana operated at 530 °C and 95 bar for 150 000 h. A non-destructive evaluation (NDE) of the microstructure using the replica method and hardness measurements on pipeline bends and welded joints with the aim to evaluate for possible damage due to creep deformation was applied. The hardness of the different zones of the welded joints, base material, heat-affected zone and the weld material itself was appropriate and corresponded to the tensile strength in the range required by the standards. A martensitic appearance in all the observed locations was noticeable. Micro-voids that arise due to creep deformation along the former austenite grain boundaries and along the martensite lamellas on the inspected sites were not observed. According to the VGB'classification, the steel corresponds to the 2b class.

14.08.2012