High Temperature Materials and Processes (Feb 2019)
The effect of MgTiO3Adding on Inclusion Characteristics
Abstract
MgTiO3 powder was directly added into molten steel at 1873K, and its effect on inclusion characteristics was studied by a scanning electron microscope and an energy dispersive spectrometer. Thermodynamic calculation indicates that MgTiO3 is unstable in molten steel and may decompose into [Ti], [O] and MgO. However, only Ti-bearing inclusions were observed in the treated sample, and Mg-bearing inclusions were absent. This can be explained by the features of wettability and stability for MgO. Compared with a Non-treated sample, both oxide and coarse MnS in treated sample were refined. For the oxide, this originates from the formation of Ti-bearing inclusion. For coarse MnS, this may be due to the fact that Ti can aggravate S segregation. Besides, this aggravation makes coarse MnS less globular. After etching, it was found that in the treated sample, Ti-bearing inclusion can induce the nucleation of intragranular acicular ferrites. This appearance was totally different from that of Non-treated sample, and indicates the effectiveness of external adding method in oxide metallurgy.
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