Effects of Remelting Current on Structure, Composition, Microsegregation, and Inclusions in Inconel 718 Electroslag Remelting Ingots

Journal Article · Sun Dec 15 04:00:00 EST 2019 · Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/S11663-019-01685-Y· OSTI ID:22933422

Shi, Xiao; Duan, Sheng-Chao; Yang, Wen-Sheng; Mao, Ming-Tao; Guo, Han-Jie; Guo, Jing ^[1]

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1. University of Science and Technology, Beijing, School of Metallurgical and Ecological Engineering (China)

The macro- and microstructures, chemical compositions, microsegregations, and nonmetallic inclusion characteristics at different positions of the as-cast IN718 ingots produced by a laboratory-scale electroslag remelting (ESR) furnace under four remelting currents (150, 200, 250, and 300 A) were compared and investigated comprehensively. The results indicate that the average melting rate increases with the increasing remelting current, and the molten pool tends to be deeper. Thus, at the same position of the ESR ingots, the volume fraction of the segregated phase, the degree of elemental segregation, and the secondary dendrite arm spacing have the same tendency to increase with the increasing remelting current and show an increasing trend from the bottom to the top along the height of each ingot. If the current is set relatively low, the oxygen and nitrogen levels in the ingots increase, the conditions that make the contents and distributions of Al and Ti become unstable. In addition, the major nonmetallic inclusions in the IN718 ESR ingots are MgO·Al{sub 2}O{sub 3} complex oxide inclusions with a three-layer structure and (Nb,Ti)N nitrides. The volume fractions and mean equivalent diameters display a downward trend with the increasing remelting current. The size and quantity of these inclusions are always larger in the upper portions of the ingots than those in the lower portions.

• OSTI ID: 22933422
• Journal Information: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science Journal Issue: 6 Vol. 50; ISSN 1073-5615; ISSN MTBSEO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CHEMICAL COMPOSITION
FURNACES
INCONEL 718
MAGNESIUM OXIDES
MELTING
MICROSTRUCTURE
NIOBIUM NITRIDES
NITROGEN
OXYGEN
SEGREGATION
TITANIUM NITRIDES