Inconel718高温合金电渣重熔铝钛元素烧损热力学分析

Thermodynamic analysis of Al and Ti element loss in electroslag remelting Inconel718 superalloy

为了研究Inconel718高温合金电渣重熔过程中渣系各组元对合金中易氧化元素铝、钛的影响,以五元渣系CaF_2-CaO-Al_2O_3-MgO-TiO_2为基,通过分子与离子共存理论,根据渣金界面中各组元的平衡反应和物质守恒,建立了Inconel718高温合金电渣重熔过程中渣金界面铝、钛元素氧化反应的热力学模型。通过分析该模型并对模型结果进行渣金平衡验证试验,验证了模型的有效性。研究结果表明,渣中CaF_2、MgO质量分数的变化对合金中铝、钛元素的影响很小;渣中Al_2O_3有烧钛增铝的作用,TiO_2有烧铝增钛的作用,CaO能够抑制铝元素的烧损;能够有效减少Inconel718高温合金电渣重熔过程中铝、钛元素烧损的渣系配比为CaO质量分数为20%～25%、TiO_2质量分数为4%～6%、MgO质量分数为1%～4%、CaF_2质量分数为50%～60%、Al_2O_3质量分数为15%～20%。

In order to study the influence of various components of slag system on the oxidizable elements Al and Ti in the alloy during the electroslag remelting process of the Inconel718 superalloy,based on the five-component slag CaF2-CaO-Al2O3-MgO-TiO2,through the molecular and ion coexistence theory,a thermodynamic model for the oxidation of Al and Ti in the slag-gold interface during the electroslag remelting process of Inconel718 superalloy was established according to the equilibrium reaction and the material conservation of each component in the slag-metal interface. By analyzing the model and performing slag-metal balance verification experiments on the model results,the validity of the model is verified. The results showed that the change of CaF2 and MgO percent in the slag has little effect on the Al and Ti elements in the alloy. The Al2O3 in the slag has the effect of burning Ti to increase Al,the TiO2 has the effect of burning Al to increase Ti,and the CaO can inhibit the burning of Al element. The slag ratio that can reduce the burning of Al and Ti during the electroslag remelting of the Inconel718 superalloy is:20%-25%CaO,4%-6%TiO2,1%-4%MgO,50%-60%CaF2,and 15%-20%Al2O3.