Assessing the condition of welded steam pipes is a key activity for the safe operation of the power plant and preventing future failures. This paper presents a method of estimating the remaining service life of a steam pipeline made of high-alloy steel, which has been in operation for a long time. The tested steam pipeline, operating for a long period of time under high pressure and high temperature conditions, experiences a series of microstructural transformations in both the base material and the weld, including cavitation due to creep. This study shows how, based on the examined microstructure, to estimate the remaining service life of a steam pipe under creep conditions, using the method of non-destructive replication metallography. Based on the classification of damage due to creep according to Wedel and Neubauer, an assessment of the remaining service life of the steam pipeline was made. The test results indicate that after long-term operation, noticeable microstructural damage occurs due to creep, and the estimated remaining service life indicates that the tested steam pipeline meets the conditions for further use. The purpose of this paper is to show the microstructural changes of a steam pipe made of high-alloy steel X10CrMoVNb9-1 after long-term operation in creep conditions. The presented data provide technical support for the safe operation of the high-temperature steam pipeline in the power plant, helping to formulate a maintenance strategy and eventual replacement of the steam pipeline, in order to ensure the safe and efficient operation of the power plant.
Bulatović et al. (Sun,) studied this question.