Examination of the microstructure of high-pressure steam pipes after 200 000 hours of operation

Abstract

This study examined the microstructure of the main steam pipes in thermal power plant using the method of metallographic replicas. The aim of the research was to analyze and assess the condition of the pipes after 200 000 hours of operation, as well as to evaluate their remaining service life and endurance under longterm loads according to the VGBS 517 standard. This standard establishes rigorous guidelines for inspecting and assessing the microstructural composition and damage due to creep in creepresistant steel for highpressure piping, boiler components, welded joints, considering the parameters such as material, wall thickness and construction. In addition to microstructure analysis, particular emphasis was placed on studying the timedependent strength of the steam pipes, especially in the context of creep. Creep or deformation under constant load over time at high temperatures is a key factor influencing the longterm performance of the pipes. The results of the conducted research will provide a broader understanding of the condition of the steam pipes after 200 000 hours of operation, identify potential defects or weaknesses in the material and enable timely implementation of appropriate maintenance or replacement measures, thereby reducing the risk of accidents and failures.