电渣重熔Inconel 625合金铝钛氧化的热力学分析

Thermodynamic Analysis of Aluminum and Titanium Oxidation During Electroslag Remelting Process of Inconel 625 Alloy

针对电渣重熔Inconel 625合金过程中Al和Ti含量的控制问题,通过渣-金平衡实验和基于离子-分子共存理论建立作用浓度热力学模型的研究,探索渣系组元对Al,Ti烧损的影响机制.研究了渣系各组元活度及活度比与渣系成分间的关系.研究结果表明:当TiO_(2)的质量分数为3%时,渣系能较好地控制Al和Ti氧化的效果.炉渣中的CaO会引起合金中Al和Ti不同程度的烧损,过量CaO会导致合金发生“烧Ti增Al”现象.升高温度可以抑制合金中Al的氧化,而降低温度可以抑制Ti的氧化.在1823 K下,能够有效减少Inconel 625合金电渣重熔过程中Al和Ti烧损的渣系组成为w(CaF_(2))=50%~60%,w(Al_(2)O_(3))=15%~20%,w(CaO)=14%~20%,w(MgO)=3%,w(TiO_(2))=2.5%~3.5%.

Slag-metal equilibrium experiments and a thermodynamic model of the action concentration based on the ion and molecule coexistence theory(IMCT)were used to study in controlling Al and Ti elements during the electroslag remelting(ESR)process of Inconel 625 alloy.The influencing mechanisms of slag components on burning loss of Al and Ti were investigated and the relationship of the activity and its ratio for each slag component with chemical composition in the system was provided,respectively.The results indicate that the slag system with the TiO_(2)of 3%has a good effect on the Al and Ti preservation.The CaO in the slag will cause different degrees of burning loss of Al and Ti,in which the excess CaO can lead to the phenomenon of burning the Ti and increasing the Al content.The Al oxidation is restrained with the temperature,in contrast to the Ti oxidation.Eventually,at the 1823 K,the composition of the slag system is selected as w(CaF_(2))=50%~60%,w(Al_(2)O_(3))=15%~20%,w(CaO)=14%~20%,w(MgO)=3%and w(TiO_(2))=2.5%~3.5%,respectively,so as to reduce the Al and Ti burnout effectively during the ESR process of Inconel 625.