The impact of repair welded joint on the life of Cr-Mo-V steel steam pipeline after service under creep conditions

摘要

Purpose: The purpose of this paper was to examine the impact of repair welded joints on the life time of primary steam pipelines after more than 200 000 h service under creep conditions. Design/methodology/approach: The investigations of microstructure using scanning microscopy, investigations of mechanical properties at room and elevated temperature, determination of brittle fracture appearance transition temperature based on impact strength tests and abridged creep tests were carried out in order to determine the residual life of the material. Findings: The completed investigations allowed the time of further safe operation of the elements of primary steam pipeline with repair welded joint to be determined in relation to the parent material and welded joint after service. Practical implications: The assessment of residual life and disposable residual life, and thus the estimation or determination of possible time of further safe operation, is of the essence in case of operating the elements much beyond the design work time. Originality/value: The obtained results of investigations are the elements of material characteristics developed by the Institute for Ferrous Metallurgy for steels and welded joints made from them working under creep conditions.