Numerical Simulation Of Hollow Ingot In Electroslag Remelting

In recent years, with the rapid development of nuclear power, petrochemical, hydropower and other energy fields, demands of large hollow forgings for its core component are growing increasingly, higher quality is required. Because of its unique orgnization and solidification characteristics, the hollow ingot has incomparable superiority in compare with the ordinary ingot. It is known that one of the efficient methods of producing quality hollow ingots is the electroslag remelting, guaranteeing the formation of a good orgnization and high level of metal properties as-cast. Though the technology of hollow ingots produced by ESR has a lot of notable advantages, it is still a new technology, the research of this technology is just at the period of beginning in abroad, there are few detailed studies and data in China as well, as a result, these scientific problems associated with this technology need to be studied in detail.A mathematical model, based on electromagnetic field equation, fluid flow equation, and heat transfer equation, was established for the simulation of ESR hollow ingot process, and then commercial software ANSYS and CFX were used to solve this model, finally the distribution of electric field, magnetic field, flow field and temperature field were obtained. Related experiments were carried out to verify the mathematical model.The existing problems during the process of ESR hollow ingots have been studied by many researchers aiming at improving the surface and interior quality of ingots. And the influence of different process parameters, such as the slag height, immersion depth and number of electrodes, power supply modes were also analyzed for the ESR hollow ingot technology.Calculation results of the influences on electric field, temperature field and flow field by different slag heights, immersion depths, number of electrodes and power supply modes indicate the molten metal pool become more shallow with the increase of the slag height; molten metal pool is deepening with the increase of the insertion depths of electrodes; and the ten electrodes arrangement's molten metal pool is deepening than the eight electrodes arrangement's, but interface temperature change between two arrangements is relatively small. Without conductive mold's molten metal pool is deepening than conductive mold. It could conclude that adopting the process of 120 mm height of slag pool,10 mm depth of the electrode insertion, the electrode diameter of 160 mm and the ten electrodes arrangement can promote the slag temperature more uniform and obtain a uniform and shallow mental bath state.