Desulfurization Behavior of Incoloy® 825 Superalloy by CaO-Al2O3-MgO-TiO2 Slag
- Title
- Desulfurization Behavior of Incoloy® 825 Superalloy by CaO-Al2O3-MgO-TiO2 Slag
- Author
- 박주현
- Issue Date
- 2021-12
- Publisher
- SPRINGER
- Citation
- METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, v. 52, NO 6, Page. 3660-3670
- Abstract
- Ni-based superalloy, which has excellent high-temperature strength and corrosion resistance, is
mainly used in aviation materials, high-performance internal combustion engines, and turbines
for thermal and nuclear power generation. For this reason, refining the impurities in Ni-based
superalloys is a very important technical task. Nevertheless, the original technology for the
melting and refining of Ni-based superalloys is still insufficient. Therefore, in this study, the
effect of the CaO-Al2O3-MgO-TiO2 slag on the removal efficiency of an impurity element sulfur
in Incoloy 825 superalloy, one of the representative Ni-based superalloys, was investigated.
The desulfurization behavior according to the change of TiO2 content and CaO/Al2O3 (=C/A,
basicity) ratio as experimental variables was observed at 1773 K (1500 C). Although the TiO2
content in the slag increases to 15 mass pct, the mass transfer coefficient of sulfur in molten alloy
showed a constant value. Alternatively, under the condition of C/A > 1.0 of slag, the mass
transfer coefficient of sulfur showed a constant value, whereas under the condition of C/A<1.0,
the mass transfer coefficient of sulfur greatly decreased as CaO decreased. Hence, in the
desulfurization of Incoloy 825 superalloy using the CaO-Al2O3-MgO-TiO2 slag, the TiO2
content in the slag does not have a considerable effect on the desulfurization rate and
desulfurization mechanism (metal phase mass transfer controlled regime), but the basicity of the
slag has a significant effect on desulfurization mechanism. When the slag basicity decreases
below the critical level, i.e., C/A<1.0, which is corresponding to sulfur distribution ratio, Ls<
200, it was confirmed that the desulfurization mechanism shifts from the metal phase mass
transfer-controlled regime to the slag phase mass transfer-controlled regime due to the variation
in the physicochemical properties of the slag such as viscosity and sulfide capacity. In addition,
the different desulfurization rates between steel and Ni alloy melts were discussed by employing
the diffusivity of sulfur in both systems.
- URI
- https://link.springer.com/article/10.1007/s11663-021-02338-9https://repository.hanyang.ac.kr/handle/20.500.11754/169562
- ISSN
- 10735615; 15431916
- DOI
- 10.1007/s11663-021-02338-9
- Appears in Collections:
- COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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