Hydrogen degradation effects on mechanical properties in T24 weld microstructures
- Spectacular failure cases of fossil power stations in the recent years exhibited severe cracking in T24 welds. The results show that hydrogen-assisted cracking up to 200 °C cannot be excluded. Hence, it is important to gain a basic understanding on how hydrogen might affect the basic material properties in the respective weld microstructures. The present study focuses on hydrogen degradation of the respective weld microstructures, i.e., the weld metal and the coarse grained heat affected zone, where actually cracking appeared in practice. Tensile tests were carried out for coarse grain heataffected zone (CGHAZ) and the weld metal in uncharged and electrochemically hydrogen-charged condition. It turned out that both microstructures show distinct tendency for gradual degradation of mechanical properties in the presence of increasing hydrogen concentration. Already for a hydrogen concentration about and above 2 ml/100 g Fe, a significant ductility reduction has been observed. SEMSpectacular failure cases of fossil power stations in the recent years exhibited severe cracking in T24 welds. The results show that hydrogen-assisted cracking up to 200 °C cannot be excluded. Hence, it is important to gain a basic understanding on how hydrogen might affect the basic material properties in the respective weld microstructures. The present study focuses on hydrogen degradation of the respective weld microstructures, i.e., the weld metal and the coarse grained heat affected zone, where actually cracking appeared in practice. Tensile tests were carried out for coarse grain heataffected zone (CGHAZ) and the weld metal in uncharged and electrochemically hydrogen-charged condition. It turned out that both microstructures show distinct tendency for gradual degradation of mechanical properties in the presence of increasing hydrogen concentration. Already for a hydrogen concentration about and above 2 ml/100 g Fe, a significant ductility reduction has been observed. SEM investigations revealed that the fracture topography changes from ductile topography in uncharged condition to intergranular topography for the CGHAZ and to ductile-brittle mix for the weld metal (WM) in hydrogen charged condition. Ti-rich inclusions were identified as central regions of quasi-cleavage fracture areas in the WM. An approximation procedure is applied to quantify the degradation intensity.…
Autor*innen: | Michael RhodeORCiD, Jörg Steger, Thomas Böllinghaus, Thomas KannengießerORCiD |
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Persönliche Herausgeber*innen: | J. Lippold, Thomas Böllinghaus, I. M. Richardson |
Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Welding in the World |
Jahr der Erstveröffentlichung: | 2016 |
Herausgeber (Institution): | International Institute of Welding |
Verlag: | Springer-Verlag GmbH |
Verlagsort: | Heidelberg |
Jahrgang/Band: | 60 |
Ausgabe/Heft: | 2 |
Erste Seite: | 201 |
Letzte Seite: | 216 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Freie Schlagwörter: | Creep resisting materials; Heat affected zone; Hydrogen embrittlement; Low alloy steels; Microstructure |
DOI: | 10.1007/s40194-015-0285-5 |
URL: | http://link.springer.com/article/10.1007/s40194-015-0285-5 |
ISSN: | 0043-2288 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 15.03.2016 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 30.05.2016 |