|
Vol.43, No.2, 148 ~ 156, 2005
|
| Title |
| Aluminum Deoxidation Equilibria and Inclusion Modification Mechanism by Calcium Treatment of Stainless Steel Melts |
| 박주현 Joo Hyun Park , 김동식 Dong Sik Kim , 김용환 Yong Hwan Kim , 이상범 Sang Beom Lee |
|
|
|
| Abstract |
| A thermodynamic equilibrium between aluminum and oxygen along with the inclusion morphology in Fe-16%Cr stainless steel was investigated to understand the fundamentals of aluminum deoxidation technology for ferritic stainless steels. Further, the effects of calcium addition on the changes in chemistry and morphology of inclusions were discussed. The measured results for aluminum-oxygen equilibria exhibit relatively good agreement with the calculated values, indicating that the introduction of the first- and second-order interaction parameters, recently reported, is reasonable to numerically express aluminum deoxidation equilibrium in a ferritic stainless steel. In the composition of dissolved aluminum content greater than about 60 ppm, pure alumina particles were observed, while the alumino-manganese silicates containing Cr₂O₃ were appeared at less than 20 mass ppm of dissolved aluminum. The formation of calcium aluminate inclusions after Ca treatment could be discussed based on the thermodynamic equilibrium with calcium, aluminum, and oxygen in the steel melts. In the composition of steel melt with relatively high content of calcium and low aluminum, the log(X_(cao)/X_(Al_(2)o_(3)) of inclusions linearly increases with increasing the log[a_(ca)/a？(Al)？？(o)] of with the slope close to unity. However, the slope of the line is significantly lower than the expected value in the composition of steel melt with relatively low calcium and high aluminum contents. (Received September 30, 2004) |
|
|
| Key Words |
| Inclusion morphology, Fe-16%Cr stainless steel, Aluminum deoxidation, Calcium treatment, Interaction parameter, Alumina, Alumino-manganese silicates, Calcium aluminates |
|
|
 |
|
