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Vol.35, No.11, 1506 ~ 1512, 1997
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| Title |
| A Study on the Reduction Kinetics of Cr2O3 in CaO-Cr2O3 Slags by Residual Aluminum in Liquid Alloy Steel |
| 하윤철 , 백영현 , 송효석 , 양재웅 Y . C . Ha , Y . H . Paik , H . S . Song , J . W . Yang |
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| Abstract |
| The Argon and Oxygen Decarburization (A.O.D) process is known as the most effective process for the stainless steel making. The aim of this study is to establish the reduction mechanism of Cr₂O₃, at the A.O.D reduction period. Synthetic solid slags diskes of CaO-Cr₂O₃ binary and also ternary systems containing Al₂O₃, or CaF₂ as additives were respectively prepared by compacting and sintering. AISI 304 stainless steel was melted in MgO crucible in semi-opened Ar-atmosphere at 1600-1700℃. The reduction was carried out by adding Al into molten alloy steel and then by placing the disk on it. The reduction rate was measured by analysing steel samples and also reacted slags. The reduction rate was controlled by the surface reaction and the first order with respect to the residual Al concentration. The amount of reduced Cr could be expressed by an exponential form; Δ[Cr]=2[Al]_0(1-e^(-k′(Cr₂O₃)⁴-(time))) The rate constant, k`, is a function of temperature, the viscosity of slag, surface area, and surface roughness factor The activation energy obtained from these was found to be 150㎉/㏖. It is interesting to note that the reaction rate increased significantly as decreasing the viscosity of interfacial liquid slag by adding Al₂O₃, or CaF₂ to the slags. |
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