摘要
Abstract
To study the microstructure characteristics of welded rotor joints after long-term service,a thermal power low-pressure welded rotor,which was made of NiCrMoV steel and had been in service for 22 years,was selected as the research objective.Microstructural analysis was carried out on the weld metal closest to the steam inlet part,and the precipitates of the welded joint was characterized in detail.The observation results of optical microscope,scanning electron microscope and transmission electron microscope showed that no defects,such as cracks and inclusions,were found in the entire weld metal part after long-term service,and no obvious grain coarsening phenomenon was observed.The morphology and distribution of precipitates in various parts of the joint were very similar,and the precipitate phase was fine and evenly distributed,with sizes ranging from 0.02 μm to 1.2 μm.The variation of hardness values of the welded joints before and after service was not significant.The research findings can provide reference for assessment of service safety of low-pressure welded rotor in steam turbine.关键词
低压焊接转子/NiCrMoV钢/长期服役/微观组织Key words
low-pressure welded rotor/NiCrMoV steel/long-term service/microstructure分类
能源与动力
