Incoloy825合金电渣重熔低氟渣系设计的热力学研究  

Thermodynamic study on design of electroslag remelting slag for Incoloy 825 Alloy

作　　者：巨建涛[1,2] 杨康帅 棘广恒 安家良 刘诗薇 JU Jian-tao;YANG Kang-shuai;JI Guang-heng;AN Jia-liang;LIU Shi-wei(School of Metallurgical Engineering,Xian University of Architecture and Technology,Xi′an 710055,China;Metallurgical Engineering Technology Research Center of Shaanxi Province,Xi′an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,西安710055 [2]陕西省冶金工程技术研究中心,西安710055

出　　处：《工程科学学报》2020年第S01期119-127,共9页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51774225,51704223)。

摘　　要：为控制Incoloy825合金中的Al、Ti含量,并减少电渣过程中氟化物的挥发.借助FactSage热力学软件,建立渣−金反应的热力学模型.设计出适宜控制Al、Ti含量的低氟渣系,探究了渣中组元与Al2O3和TiO2活度比的关系,并通过高温渣–金平衡实验进行验证.结果表明:当渣中CaO和Al2O3含量增加,导致lg(a2Al2O3/a3TiO2)值升高,即合金中Ti含量降低,Al含量升高;与此相反,渣中TiO2含量升高,使lg(a2Al2O3/a3TiO2)值降低,即Ti含量增加,Al含量减少;渣中CaF2和MgO含量的增加对lg(a2Al2O3/a3TiO2)的影响较小.合金中Al、Ti含量相差较大时,合金中Ti元素易氧化;Al、Ti含量相差较小时,Al元素易氧化.渣中CaO的质量分数为30%~33%、Al2O3的质量分数为30%~33%、TiO2的质量分数为6%~12%、CaF2的质量分数为20%~30%、MgO的质量分数为1%~5%时,能够有效控制合金中Al、Ti元素含量.Incoloy825 alloy is extensively used in the aerospace and petrochemical industries owing to its excellent corrosion resistance and mechanical properties.It is a solid solution-strengthened Fe−Cr−Ni-based corrosion-resistant alloy.The changes in the Al and Ti contents of the alloy determine the precipitation temperature of the strengthening phasesγ'(Ni3AlTi)and Ti(C,N)in the alloy.At present,the main production methods of Incoloy825 alloy are vacuum melting and electroslag remelting.However,owing to the reaction of the components in the slag with the Al and Ti elements in the alloy during the electroslag remelting process,the axial component distribution of the Al and Ti elements in the electroslag ingot is not homogeneous,which seriously affects the quality of the electroslag ingot.It is necessary to control the Al and Ti contents in Incoloy825 alloy and reduce the volatilization of fluoride during the electroslag remelting process.The thermodynamic model of slag metal reaction was established using FactSage thermodynamic software.A low-fluorine slag system suitable for controlling Al and Ti contents was designed,and the relationship between the components in the slag and the activity ratios of Al2O3 and TiO2 was studied,the result was verified by a high-temperature slag metal equilibrium experiment.The results show that the CaO and Al2O3 contents in slag increases with increase in thelg(a2Al2O3/a3TiO2)value,while the Ti content in the alloy decreases with increasing Al content.Moreover,as the TiO2 content in the slag increases,thelg(a2Al2O3/a3TiO2)value decreases,Ti content increases and Al content decreases.The CaF2 and MgO contents in the slag increase have a little effect with thelg(a2Al2O3/a3TiO2)value.When the difference between the Al and Ti contents in the alloy is large,the elemental Ti inthe alloy is easy to be oxidized;when difference between the Al and Ti contents is small,the elemental Al is easy to be oxidized.When the mass percent of CaO and Al2O3 in the slag are 30%−33%respectively,the mass

关 键 词：热力学 电渣重熔 Incoloy825合金 FactSage 活度比 

分 类 号：TF141[冶金工程—冶金物理化学]