THE EFFECT OF SIGMA-PHASE FORMATION ON LONG-TERM DURABILITY OF SUPER 304H STEEL

1,2 HORVATH Jakub.
Co-authors:
3 KRAL Petr 1 JANOVEC Jiří 3 SKLENICKA Václav
Institutions:
1 Czech Technical University in Prague, Faculty of mechanical engineering, Department of materials engineering, Prague, Czech Republic, EU
2 UJP PRAHA a.s., Prague, Czech Republic, EU
3 Institute of physics of materials, Academy of sciences of the Czech Republic, Brno, Czech Republic, EU
Conference:
24th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, June 3rd - 5th 2015
Proceedings:
Proceedings 24th International Conference on Metallurgy and Materials
Pages:
505-510
ISBN:
978-80-87294-58-1
ISSN:
2694-9296
Published:
12th January 2015
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
39 views / 11 downloads
Abstract

This work presents results of the analysis of phases formed in a SUPER 304H steel during a medium-term static isothermal ageing (675 °C/15000 h). The investigations of the precipitates were especially focused on the occurrence of sigma-phase because its formation leads to the serious embrittlement.The evaluation and distribution of brittle sigma-phase were determined on macroscopic level by using light microscopy/colour etching. The microstructure was also investigated on microscopic level by scanning electron microscopes Tescan Lyra 3 and JEOL JSM 5410 equipped by electron backscatter diffraction unit and by transmission electron microscope Jeol 2100F. This work also investigates the effect of sigma-phase formation on the impact strength of an aged state of SUPER 304H steel. For comparison reasons the microstructure and the mechanical properties of the initial as-received) state were also investigated. It was found that the formation of brittle sigma-phase in the aged and therefore degraded microstructure led to the significant decrease of the impact strength. The influence of brittle sigma-phase on long-term durability of the degraded steel regarding its insufficient impact strength is discussed.

Keywords: austenitic steel, medium-term ageing, SUPER 304H, sigma-phase, impact strength

© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Scroll to Top