Kinetic Model Of Desulfurization During The Different Atmosphere Electroslag Remelting Process

Sulfur exists in the form of harmful element for most kinds of steel,which mainly affects the thermal processing performance,corrosion resistance,mechanical performance and welding performance of steel.Therefore,in order to ensure the quality of steel,the desulfurization becomes a very important task,and the key to control sulfur content in steel is establishing the kinetic model of desulphurization to predict the change of sulfur content in steel.Electroslag remelting(ESR)process is an important technology in modern metallurgy engineering,which can be divided into protective electroslag remelting and unprotective electroslag remelting according to remelting atmosphere.Because the ingot made by ESR technology has the advantages of compact structure,small inclusion and dispersion,it has become an important technology to produce special steel.The control of sulfur content in special steel production is very strict.Therefore,the establishment of desulfurization kinetic model of electroslag remelting in different atmosphere plays an important role in solving the control problem of sulfur content in steel.In this paper,in order to control the sulfur content in electroslag remelting during different atmosphere,the research is mainly carried out from the following three aspects.First and foremost,since mass transfer kinetic model is the most basic solution,the desulfurization kinetic model of electroslag remelting under different atmosphere is established;Second,as an important means of model verification,the experimental remelting of specific steel was made in different atmosphere using the pressurized electroslag furnace.Thirdly,through the model the simulation value and experiment of the measured values of compare analysis,an assessment on the established model,under different atmosphere for electroslag remelting process lay a foundation of sulfur content control.Firstly,based on the theory of thin film theory and infiltration,on the basis of the existed models,analyzed in detail under different atmosphere,the mechanism of mass transfer at the end of electrode melting to form droplet,droplet passing through slag layer,metal molten pool,slag atmospheric contact are researched,etc,using Matlab to solve the question.The mass transfer processes of[S]+(S2-)?[Mn]+(MnO)?[Si]+(SiO2)?[Al]+(Al2O3)?[Fe]+(FeO)?[O]+(O2-)systems were studied.The dynamic model of electroslag remelting desulfurization under different atmosphere with desulfurization as the center was established successfully.Compared with the existing models,the model takes into full account the changes in the distribution coefficient of elements in the remelting process,and the desulfurization effect of the added gas relative to the sulfur in the slag.Subsequently,40%CaF2-30%Al2O3-30%CaO slag system and T10 consumable electrode were adopted,and 50 kg pressurized ESR furnace was used for electroslag remelting experiment under different atmosphere.By measuring the change trend of S,Mn,Si,Al and O in steel with the contact time between slag and metal,the effect of electroslag remelting on the mass transfer of various elements in steel under different atmosphere was studied.Experimental data show that in steel,Mn,Si,S,O elements such as content as the remelting process of rising,and the Al content in the steel coming down,but still higher than the original Al content of consumable electrode.Under different atmosphere of remelting low alloy steel T10 with high carbon and low sulfur,desulfurization rate achieves 30%,rather than protective remelting,according to data due to oxygen in the atmosphere of sulphur in slag removal effect,the desulfurization rate can reach 35%.Finally,the simulation values of desulphurization kinetics during electroslag remelting under different atmosphere and the measured values of smelting products under different atmosphere are compared.The results show that the simulated values are in good agreement with the measured values,and the model has a good predictive effect on S,Mn,Si,Al and O in steel.Regarding the desulfurization in terms of location electroslag remelting in the process of under different atmosphere,at the end of electrode position the melt desulfurization ability was significantly higher than that of molten drops through the slag layer and the metal molten pool in desulfurization ability,which is consistent with the references.