Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy
Using optical microscope， scanning electron microscope and energy dispersive spectrometer， the casting microstructure of 12 tons of ingots of as-cast condition C650R nickel-based alloy used in the 650 ℃ultra-supercritical steam turbine rotor， smelted by the three-process method （VIM+PESR+VAR）， and t...
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Editorial Office of Special Steel
2025-08-01
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| Series: | Teshugang |
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| Online Access: | https://www.specialsteeljournal.com/fileup/1003-8620/PDF/2025-00079.pdf |
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| author | Kou Jinfeng, Bai Yaguan, Nie Yihong, Zhang Xin, Zhang Bingbing, Li Jinshan, He Yixuan |
| author_facet | Kou Jinfeng, Bai Yaguan, Nie Yihong, Zhang Xin, Zhang Bingbing, Li Jinshan, He Yixuan |
| author_sort | Kou Jinfeng, Bai Yaguan, Nie Yihong, Zhang Xin, Zhang Bingbing, Li Jinshan, He Yixuan |
| collection | DOAJ |
| description | Using optical microscope， scanning electron microscope and energy dispersive spectrometer， the casting microstructure of 12 tons of ingots of as-cast condition C650R nickel-based alloy used in the 650 ℃ultra-supercritical steam turbine rotor， smelted by the three-process method （VIM+PESR+VAR）， and the microstructure after different homogenization treatments were studied. The high-temperature thermoplasticity before and after homogenization treatment was also compared. The results show that in the self-consumption ingots of ϕ960 mm ingot size produced using the three-process smelting method， there is a significant segregation. The main segregation elements are Mo， Nb， and Ti， which are segregated between dendrites. Within the crystal， the main precipitated phase is a MC-type primary carbide rich in Mo， Nb， Ti， and Zr. The carbides have an irregular shape， with small granular M23C6 primarily at the grain boundaries， along with a small amount of irregular MC-type primary carbide rich in Mo， Nb，and Ti. Based on the results of dendrite elimination， carbides re-dissolution， and changes in the residual segregation coefficients of three elements （Mo， Nb， Ti） after different homogenization treatments， it was determined that the homogenization process for a 12-ton C650 nickel-based alloy ingot should be 1 200 ℃-1 220 ℃ with a holding time of over 96 hours. Compared to the cast state， the samples after homogenization treatment show a significant improvement in high-temperature plasticity， which lays a favorable foundation for the smooth casting of the ingot. |
| format | Article |
| id | doaj-art-158d5e32e92843e8a92c9ec5b2eaad4a |
| institution | DOAJ |
| issn | 1003-8620 |
| language | zho |
| publishDate | 2025-08-01 |
| publisher | Editorial Office of Special Steel |
| record_format | Article |
| series | Teshugang |
| spelling | doaj-art-158d5e32e92843e8a92c9ec5b2eaad4a2025-08-20T03:22:19ZzhoEditorial Office of Special SteelTeshugang1003-86202025-08-0146410010610.20057/j.1003-8620.2025-00079Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based AlloyKou Jinfeng, Bai Yaguan, Nie Yihong, Zhang Xin, Zhang Bingbing, Li Jinshan, He Yixuan01 Tianjin Heavy Industries Research & Development Co.， Ltd.， Tianjin 300457， China；2 Northwestern Polytechnical University， Xi´an 710072， ChinaUsing optical microscope， scanning electron microscope and energy dispersive spectrometer， the casting microstructure of 12 tons of ingots of as-cast condition C650R nickel-based alloy used in the 650 ℃ultra-supercritical steam turbine rotor， smelted by the three-process method （VIM+PESR+VAR）， and the microstructure after different homogenization treatments were studied. The high-temperature thermoplasticity before and after homogenization treatment was also compared. The results show that in the self-consumption ingots of ϕ960 mm ingot size produced using the three-process smelting method， there is a significant segregation. The main segregation elements are Mo， Nb， and Ti， which are segregated between dendrites. Within the crystal， the main precipitated phase is a MC-type primary carbide rich in Mo， Nb， Ti， and Zr. The carbides have an irregular shape， with small granular M23C6 primarily at the grain boundaries， along with a small amount of irregular MC-type primary carbide rich in Mo， Nb，and Ti. Based on the results of dendrite elimination， carbides re-dissolution， and changes in the residual segregation coefficients of three elements （Mo， Nb， Ti） after different homogenization treatments， it was determined that the homogenization process for a 12-ton C650 nickel-based alloy ingot should be 1 200 ℃-1 220 ℃ with a holding time of over 96 hours. Compared to the cast state， the samples after homogenization treatment show a significant improvement in high-temperature plasticity， which lays a favorable foundation for the smooth casting of the ingot.https://www.specialsteeljournal.com/fileup/1003-8620/PDF/2025-00079.pdfc650r nickel-based alloy； large ingot； segregation； homogenization |
| spellingShingle | Kou Jinfeng, Bai Yaguan, Nie Yihong, Zhang Xin, Zhang Bingbing, Li Jinshan, He Yixuan Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy Teshugang c650r nickel-based alloy； large ingot； segregation； homogenization |
| title | Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy |
| title_full | Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy |
| title_fullStr | Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy |
| title_full_unstemmed | Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy |
| title_short | Microstructure and Homogenization Process of Large Ingot of As-cast Condition C650R Nickel-based Alloy |
| title_sort | microstructure and homogenization process of large ingot of as cast condition c650r nickel based alloy |
| topic | c650r nickel-based alloy； large ingot； segregation； homogenization |
| url | https://www.specialsteeljournal.com/fileup/1003-8620/PDF/2025-00079.pdf |
| work_keys_str_mv | AT koujinfengbaiyaguannieyihongzhangxinzhangbingbinglijinshanheyixuan microstructureandhomogenizationprocessoflargeingotofascastconditionc650rnickelbasedalloy |