Abstract
The kinetics model for multi-component diffusion DICTRA was applied to analyze the formation and retainment of δ-ferrite during solidification and cooling of GX4-CrNiMo-16-5-1 cast supermartensitic stainless steel. The obtained results were compared with results from the Schaeffler diagram, equilibrium calculations and the Scheil model in Thermo-Calc, and validated by using microscopy and energy dispersive X-ray spectroscopy for chemical analysis on a cast ingot. The kinetics model showed that micro-segregation from solidification homogenizes within 2–3 s (70 °C) of cooling, and that retained δ-ferrite originates from the incomplete transformation to austenite. The kinetics model predicted the measured amount of δ-ferrite and the partitioning of Cr and Ni reasonably well. Further, it showed that slower cooling for the investigated alloy leads to less retained δ-ferrite, which is in excellent agreement with experimental results.
Original language | English |
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Journal | Materials & Design |
Volume | 118 |
Pages (from-to) | 138-145 |
ISSN | 0264-1275 |
DOIs | |
Publication status | Published - 2017 |
Keywords
- Casting
- Delta ferrite
- Diffusion
- Kinetics modeling
- Solid state transformation
- Solidification
- Supermartensitic stainless steel