Influence of eutectic phase precipitation on cracking susceptibility during forging of a martensitic stainless steel for turbine shaft applications
| Autor: | L. Ebacher, S. Dourandish, Gholam Reza Ebrahimi, Mohammad Jahazi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
02 engineering and technology Martensitic stainless steel engineering.material 01 natural sciences Forging Biomaterials Solidification Electron backscatter diffraction (EBSD) analysis Phase (matter) 0103 physical sciences Ingot Eutectic system 010302 applied physics Mining engineering. Metallurgy Eutectic carbide Hot working Metallurgy Metals and Alloys TN1-997 021001 nanoscience & nanotechnology Surfaces Coatings and Films Volume fraction Ceramics and Composites engineering Grain boundary 0210 nano-technology Electron backscatter diffraction |
| Zdroj: | Journal of Materials Research and Technology, Vol 13, Iss, Pp 260-270 (2021) |
| ISSN: | 2238-7854 |
| Popis: | The presence of the eutectic phase (delta ferrite + M23C6) in martensitic stainless steels brings significant deterioration of the in-service mechanical properties of the critical components such as turbine shaft made of these alloys. In the present study, thermodynamic and kinetics of eutectic phase formation during solidification and the reheating stages before forging of a large size X38CrMo16 martensitic stainless steel ingot are investigated. Material characterization and microstructural evolution were characterized in three different zones of a large size ingot. It was observed that the forging temperature and the solidification rate were the two most effective parameters influencing the volume fraction of the eutectic phase and its morphology. Optical and electron microscopy observations along with Energy Dispersion Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) measurements were used in the investigation. The results showed that the eutectic phase precipitated primarily at the grain boundaries. Furthermore, a clear evolution on the morphology and volume fraction of the eutectic phase including thin film-like and skeleton-like carbides was found from the outer surface to the center of the ingot along the radial direction. EDS analysis revealed the substantial presence of chromium, molybdenum, and carbon within the M23C6 along the grain boundaries. Phase transformation and the precipitation phase sequences were analyzed as a function of temperature and composition of eutectic transformation using the Thermo-Calc software and the predictions were validated with experimental findings. |
| Databáze: | OpenAIRE |
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