A STUDY ON THE TITANIUM LOSS DURING ELECTROSLAG REMELTING HIGH TITANIUM AND LOW ALUMINUM CONTENT SUPERALLOY
Chen Chongxi; Wang Yong; Fu Jie and Chen Enpu (Beijing University of Iron and Steel Technology)
Cite this article:
Chen Chongxi; Wang Yong; Fu Jie and Chen Enpu (Beijing University of Iron and Steel Technology). A STUDY ON THE TITANIUM LOSS DURING ELECTROSLAG REMELTING HIGH TITANIUM AND LOW ALUMINUM CONTENT SUPERALLOY. Acta Metall Sin, 1981, 17(1): 50-57.
Abstract The titanium loss during electroslag remelting superalloys A286 and V57 has been studied. It was shown that TiO_2 becomes the predominant oxidant causing the titanium loss of the superalloys when the concentration of TiO_2 in slag used is higher enough, and that the oxide of lower valence titanium which may be kept in eqilibrium with titanium in molten superalloy seems mainly to be Ti_3O_5. The controlling factor for the rate of titanium loss may be the speed of mass transfer of Ti~(4+) across metal/slag interface which increases with the increase of concentration of TiO_2 in the slag. Thus, the remedy for its titanium loss will be dependent upon reducing Ti~(3+) diffusion rate toward slag/atmosphere interface. Attempt has also been made on the correlation between TiO_2 concentration in the slag and the mass transfer coefficient of Ti~(4+) in CaF_2-Al_2O_3-TiO_2 slag system across either electrode/slag or metal pool/slag interfaces at 17004±10℃. The mass transfer coefficient of Ti~(4+) may be expressed as:k_(e/s)=6.59exp(-0.078TiO_2), 10~(-2)cm/sk_(p/s)=2.84exp(-0.079TiO_2), 10~(-2)cm/s The mass transfer coefficient of Ti~(3+) toward slag/atmosphere interface was measured, i.e. 2.2×10~(-1) cm/s at 1500℃.
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