| The high temperature alloy containing Al and Ti has high temperature performance because it contains certainγandγ’strengthening phases,and its main component is Ni3.Therefore,the content of Al and Ti in the steel ingot directly affects the composition and content of the strengthening phase in the superalloy,which in turn leads to the generation of the brittle phase,which causes problems such as cracks in the processing of the superalloy and affects the high temperature performance of the alloy.Therefore,controlling the burning of Al and Ti elements in the process of superalloy smelting production is an important part of ensuring the performance of high-temperature alloys.Electroslag remelting is a necessary process for smelting high temperature alloys.It is also the most prone to the burning of Al and Ti elements and the uneven distribution of Al and Ti elements along the direction of electroslag ingots.Studying the burning loss of Al and Ti in electroslag remelting process is important.In this subject,the effect of multi-component slag system on the burning of easily oxidized elements such as Al and Ti in Inconel718 superalloy is studied.Firstly,the thermodynamic model of five-component slag was established based on the theory of molecular and ion coexistence,and the effects of different components of slag system on the burning of Al and Ti elements in Inconel718 superalloy electroslag remelting process were discussed.The content of TiO2 which minimizes the burning loss of Al and Ti elements and the composition of the corresponding five-component slag system are obtained;then the model results are verified in the laboratory.Since the slag shell needs a certain lubricity and high temperature strength in the ingot electroslag remelting process,a certain amount of SiO2 is added to the slag system to ensure the performance of the slag system.In this paper,the thermodynamic model of six-component slag was established based on the theory of molecular and ion coexistence.The effects of each component on Al and Ti elements were obtained.At the same time,the content of SiO2 which minimizes the burning loss of Al and Ti elements and the composition of the corresponding six-component slag system are obtained,and the results of the model are verified in the laboratory.The results show that in the five-membered and six-membered slag systems for electroslag remelting,CaF2 and MgO have little effect on the Al and Ti elements in the alloy compared with other components.Al2O3 has the effect of increasing Al to burn Ti;TiO2 has the effect of burning Al to increase Ti;SiO2 has the effect of burning Al to burn Ti;CaO can suppress the burning of Al element;the increase of temperature can inhibit the burning of Al and aggravate the burning of Ti element;the temperature decrease can inhibit the burning of Ti element and accelerate the burning of Al element.In the fixed electroslag remelting process,the five-component slag component which can reduce the burning of Al and Ti in Inconel718 superalloy is Al2O3 content of 15%～20%,CaO content of 20%～25%,and TiO2 content of 4%～6%,MgO content is 1%～4%,CaF2 content is 50%～60%.In the ingot electroslag remelting process,the six-component slag component which can reduce the burning of Al and Ti in IN718 superalloy is Al2O3 content of 20%～25%,CaO content of 25%～30%,and TiO2 content.4%～6%,MgO content is 1%～4%,CaF2 content is 50%～60%,SiO2content is 0%～1%. |
