Electroslag remelting process will be an important method for manufacturing heavy casing and forging due to its ability to improve the cleanness, macrostructure, microstructure, the distribution and size of non-metallic inclusions. In this paper, a finite element coupling model has been developed based on four electrodes configuration mode for manufacturing large ingot. Maxwell equation, Faraday's law, NavierStokes equation, heat transfer equation has been adopted in the model to analyze the current density, Joule-heat density, magnetic induction intensity and electromagnetic force and fluid flow distribution. The impact of slag depth, electrodes immersion depth and filling ratio on the molten pool depth has been analyzed. Results indicated that four electrodes with two sets of bifilar configuration are better than single phase with one electrode type. The molten pool is shallower for four electrodes than conventional single electrode mode, which is in favor of improving large ingot quality. The larger slag pool depth is the shallower the molten pool is. The depth of molten steel pool increases with the increasing of electrode immersion depth under the same slag depth condition. In addition, increasing filling ratio can reduce the depth of molten steel pool, but the filling ratio should be less than 0.6 according to area for general materials. Comparing to the single electrode mode four electrodes configuration mode is in favor of manufacturing large ingot.

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Kinetics of slag/metal reaction were investigated experimentally using 50 kg electroslag remelting (ESR) furnace in order to clarify the effect of slag containing different CaO and TiO 2 content on titanium, aluminum and silicon content during the ESR process with 1Cr21Ni5Ti stainless steel. The results obtained show that the more CaO content in slag is, the more aluminum content in ingots increases. The lg ([Al] 4 / [Ti] 3 ) increases with the increase of slag temperature in the first 13 minutes during the ESR process, and after the slag temperature tends to be stable, the lg( [Al] 4 / [Ti] 3 ) decreases with the increase of TiO 2 content in the rest process. The penetration and film theories were employed to analyze the rate determining step of slag/metal reaction, and it was found that the rate determining step of the reaction was the mass transfer of aluminum through the molten steel, silica through the slag and titanium on both of the metal and slag sides. The slag containing low CaO content combined with extra titania constantly added into molten slag in the first temperature-rising period is suitable for electroslag remelting of 1Cr21Ni5Ti stainless steel with high titanium and low aluminum content.

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