Study of cracking and microstructure in Co-free valve seat hardfacing

Loading...
Thumbnail Image
Access rights
openAccess
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal
View/Open full text file from the Research portal
Date
2022-06
Major/Subject
Mcode
Degree programme
Language
en
Pages
14
Series
Nuclear Materials and Energy, Volume 31
Abstract
For reducing the radiological hazard, Co-free hardfacing alternatives have been used to replace the traditional Co-based hardfacing alloys in nuclear power plant applications. However, manufacturing a defect-free Co-free hardfacing is challenging. Reduced galling resistance and mechanical properties exhibited by common replacement alloys in some conditions limit the application. This issue is important for the operating nuclear power plants with lifetime extension and also for the new builds. In this paper, a failed industrial hardfacing was studied. Through-the-thickness cracks of the Co-free hardfacing deposit with NOREM 02 on a nuclear swing check plug were detected. The potential cause of the brittle interdendritic cracking was studied and the detailed microstructure of the Co-free hardfacing analysed. The solidification defects during the manufacturing and the lacking of ferrite phase in the microstructure together with the potentially non-optimized handling procedures are concluded to be the causes of the observed cracking.
Description
Keywords
Hardfacing, Cobalt-free, Valve, Nuclear, Microstructure, WEAR-RESISTANCE, GALLING RESISTANCE, FRACTURE-TOUGHNESS, IRON, ALLOYS, STEEL, TEMPERATURE, PERFORMANCE, HARDNESS
Other note
Citation
Que, Z, Ahonen, M, Virkkunen, I, Nevasmaa, P, Rautala, P & Reinvall, H 2022, ' Study of cracking and microstructure in Co-free valve seat hardfacing ', Nuclear Materials and Energy, vol. 31, 101202 . https://doi.org/10.1016/j.nme.2022.101202