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

Zaiqing Que; Matias Ahonen; Iikka Virkkunen; Pekka Nevasmaa; Paavo Rautala; Hannu Reinvall

doi:10.1016/j.nme.2022.101202

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

Zaiqing Que^*
, Matias Ahonen
, Iikka Virkkunen
, Pekka Nevasmaa
, Paavo Rautala
, Hannu Reinvall

^*Corresponding author for this work

BA4509 Advanced materials for nuclear energy

Aalto University
Teollisuuden Voima Oyj
VTT (former employee or external)

Research output: Contribution to journal › Article › Scientific › peer-review

13 Citations (Scopus)

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.

Original language	English
Article number	101202
Journal	Nuclear Materials and Energy
Volume	31
DOIs	https://doi.org/10.1016/j.nme.2022.101202
Publication status	Published - Jun 2022
MoE publication type	A1 Journal article-refereed

Funding

The work is supported by customer research project 118577 NOREM02_MP funded by Teollisuuden Voima Oyj and SAFIR 2022 NOCO+ (Cobalt-free hardfacings) project. The authors would like to express their gratitude for the experimental contributions from T. Lehtikuusi and J. Lukin of VTT. The authors would like to thank A. Forsström, U. Ehrnstén and H. Hänninen for support.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 9 Industry, Innovation, and Infrastructure

Keywords

Cobalt-free
Hardfacing
Microstructure
Nuclear
Valve

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10.1016/j.nme.2022.101202Licence: CC BY

Cite this

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title = "Study of cracking and microstructure in Co-free valve seat hardfacing",

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.",

keywords = "Cobalt-free, Hardfacing, Microstructure, Nuclear, Valve",

author = "Zaiqing Que and Matias Ahonen and Iikka Virkkunen and Pekka Nevasmaa and Paavo Rautala and Hannu Reinvall",

note = "Funding Information: The work is supported by customer research project 118577 NOREM02\_MP funded by Teollisuuden Voima Oyj and SAFIR 2022 NOCO+ (Cobalt-free hardfacings) project. The authors would like to express their gratitude for the experimental contributions from T. Lehtikuusi and J. Lukin of VTT. The authors would like to thank A. Forsstr{\"o}m, U. Ehrnst{\'e}n and H. H{\"a}nninen for support. Publisher Copyright: {\textcopyright} 2022 The Authors",

year = "2022",

month = jun,

doi = "10.1016/j.nme.2022.101202",

language = "English",

volume = "31",

journal = "Nuclear Materials and Energy",

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publisher = "Elsevier",

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T1 - Study of cracking and microstructure in Co-free valve seat hardfacing

AU - Que, Zaiqing

AU - Ahonen, Matias

AU - Virkkunen, Iikka

AU - Nevasmaa, Pekka

AU - Rautala, Paavo

AU - Reinvall, Hannu

N1 - Funding Information: The work is supported by customer research project 118577 NOREM02_MP funded by Teollisuuden Voima Oyj and SAFIR 2022 NOCO+ (Cobalt-free hardfacings) project. The authors would like to express their gratitude for the experimental contributions from T. Lehtikuusi and J. Lukin of VTT. The authors would like to thank A. Forsström, U. Ehrnstén and H. Hänninen for support. Publisher Copyright: © 2022 The Authors

PY - 2022/6

Y1 - 2022/6

N2 - 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.

AB - 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.

KW - Cobalt-free

KW - Hardfacing

KW - Microstructure

KW - Nuclear

KW - Valve

UR - https://www.scopus.com/pages/publications/85134062218

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DO - 10.1016/j.nme.2022.101202

M3 - Article

AN - SCOPUS:85134062218

SN - 2352-1791

VL - 31

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

M1 - 101202

ER -

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

Abstract

Funding

UN SDGs

Keywords

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