A wet-steam pipeline fracture
Prelom cevovoda za vlažno paro

english

2007

volume 41, issue 3

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

The operational reliability of a system determines the systemćs availability and costs during its lifetime. Taking care of the reliability usually starts with knowledge of the operating conditions that need to be considered during the design, fabrication and maintenance of the system. In the case of a system or component failure, it is necessary to know the causes and the degradation mechanisms. An analysis of a fractured low-pressure wet-steam pipeline from a heat exchanger was performed. The fracture was located in the fillet weld's heat-affected zone. Visual testing, chemical analysis, hardness measurements and metallographic examinations were carried out. The fracture surface was quite damaged, and so the number of fatigue-crack propagation cycles could not be determined. An examination of the microstructure revealed that the fatigue crack occurred in the heat-affected zone, where the plasticity and toughness had been diminished due to the material overheating at the welding. As a result of the fracture analysis the industrial facility concerned extended the scope of its inspection of wet-steam pipelines.

16.09.2009