Evolution of grain-to-grain second order internal stresses during long-term service in a dry-steam pipe steel

Gy Gemes, L. Balogh, T. Ungár

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The lifetime of dry steam pipes in fossil fuelled power plants in the Central European region, especially in Hungary, is expected to be about 30 years. Besides gauge changes followed by metric controlling methods, the microstructure of the steel materials is also deteriorating due to operation at about 540°C and at about 165 bar. High resolution X-ray fine profile analysis reveals that large grain-to-grain, second-order residual internal stresses develop during the service period that finally, closer to the end of the expected life period of the materials, decrease strongly. The evolution of grain-to-grain internal stresses is explained on the basis of elastic anisotropy of steel, whereas the decrease of these internal stresses is attributed to the deterioration of the grain boundary structure by precipitate coarsening and void formation during operation of the dry steam pipes at 540°C and 165 bar.

Original languageEnglish
Pages (from-to)33-39
Number of pages7
JournalKovove Materialy
Volume48
Issue number1
DOIs
Publication statusPublished - Apr 23 2010

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Keywords

  • Grain-to-grain internal stresses
  • High resolution X-ray diffraction
  • Intergranular stresses
  • Lifetime of dry-steam pipe steel
  • Second-order stresses

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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