Thermal embrittlement of simulated heat-affected zone in cast austenitic stainless steels
- Yokohama National Univ. (Japan)
- Japan Power Engineering and Inspection Corp. (Japan)
Metallurgical factors controlling thermal embrittlement in the heat-affected zone (HAZ) of cast austenitic stainless steels were investigated by using the simulated HAZ. It was shown that the simulated HAZ was more susceptible to the thermal embrittlement by aging at 673 K in correspondence with its higher tendency to age hardening and a higher content of ferrite than the parent casting. Electron microprobe analyzer measurement showed that application of the simulated thermal cycle gave a change in the chemical composition of the ferrite, which might be a cause of the higher age hardening of the ferrite in the simulated HAZ. This higher ferrite hardness had a good correlation with fine precipitates of presumably G-phase in the ferrite grain, which existed more in the simulated HAZ than in the parent casting, though it is not clear whether this correlation was only apparent. Ductility of the austenite portion was found to reduce remarkably when surrounded by the hard ferrite of a high fraction. Annealing after aging restored CTOD to some degree. Aging after fatigue cracking gave more embrittlement than a usual procedure for preparation of test specimens, i.e., fatigue cracking after aging.
- OSTI ID:
- 655467
- Journal Information:
- Welding Journal, Journal Name: Welding Journal Journal Issue: 8 Vol. 77; ISSN 0043-2296; ISSN WEJUA3
- Country of Publication:
- United States
- Language:
- English
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