Microstructural degradation in compound tubes

Jorma Salonen, Pertti Auerkari

    Research output: Book/ReportReport


    In order to quantify microstructural degradation at high temperatures, samples of SA 210 / AISI 304 L compound tube material were annealed in the temperature range 540 - 720°C for 1 to 1 000 hours. The hardness of the annealed material was measured and the microstructure of the samples was investigated with optical and scanning electron microscopy. Microstructural degradation was characterised by the carbide structure in the ferritic-pearlitic base material and by the depth of decarburised and carburised zones of the compound tube interface. The observed changes were quantified in terms of their time and temperature dependence and diffusion coefficients of the process. The results can be used in estimating the extent of thermal exposure of high-temperature components after long-term service or after incidences of overheating.
    Original languageEnglish
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Number of pages29
    ISBN (Print)951-38-4937-6
    Publication statusPublished - 1996
    MoE publication typeNot Eligible

    Publication series

    SeriesVTT Publications


    • microstructure
    • degradation
    • thermal degradation
    • tubes
    • temperature
    • materials
    • hardness
    • measurement
    • microscopes
    • carbides
    • carburizing


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