Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable elec...Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage^(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.展开更多
Slag is the heart of electroslag remelting(ESR)process.A new mathematical model to design the optimized slag for ESR was developed based on slag–metal equilibrium theory,ion and molecule coexistence theory and modifi...Slag is the heart of electroslag remelting(ESR)process.A new mathematical model to design the optimized slag for ESR was developed based on slag–metal equilibrium theory,ion and molecule coexistence theory and modified Butler’s equation.It was assumed that an overall thermodynamic equilibrium did exist at electrode tip–slag interface.With this model,the equilibrium slag and its surface tension could be obtained quantitatively when the initial compositions of consumable electrode were given.An industrial experiment with four types of slags was carried out in a special steel plant in China.The variation of Al,Si and Mn corresponded well with the deviation of corresponding oxide from equilibrium,reflecting the reasonability of the model.Besides that,the effects of Al in electrode as well as CaO,CaF2 and MgO in slag on the equilibrium slag,dissolved oxygen and surface tension were discussed in detail.展开更多
基金financially supported by Xining Special Steel Plant and the National Natural Science Foundation of China (No. 51674024)
文摘Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage^(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.
基金The authors wish to express their gratitude to Xining Special Steel Plant,Chinathe National Natural Science Foundation of China(Grant Nos.51874034 and 51674024)for their financial support.
文摘Slag is the heart of electroslag remelting(ESR)process.A new mathematical model to design the optimized slag for ESR was developed based on slag–metal equilibrium theory,ion and molecule coexistence theory and modified Butler’s equation.It was assumed that an overall thermodynamic equilibrium did exist at electrode tip–slag interface.With this model,the equilibrium slag and its surface tension could be obtained quantitatively when the initial compositions of consumable electrode were given.An industrial experiment with four types of slags was carried out in a special steel plant in China.The variation of Al,Si and Mn corresponded well with the deviation of corresponding oxide from equilibrium,reflecting the reasonability of the model.Besides that,the effects of Al in electrode as well as CaO,CaF2 and MgO in slag on the equilibrium slag,dissolved oxygen and surface tension were discussed in detail.
