Thermal Analysis And Insulation Methods Of Coil In The Electromagnetic Induction Controlled Automated Steel Teeming System

During the iron and steel production process,stuffing sand seriously pollutes the molten steel and leads to the automatic casting rate less than 100%,which limits the development of clean steel production technology.An Electromagnetic Induction Controlled Automated Steel Teeming technology(EICAST)solves the problems caused by stuffing sand.However,after containing the molten steel in ladle,the ambient temperature of induction coil exceeds 800?before it works because of the heat conduction from high temperature molten steel,which seriously restricts the development of the EICAST technology.In order to prolong the service life of induction coil,numerical simulation and experiment methods were used in this paper to analyze the ambient temperature of induction coil in the EICAST system,and to obtain the influence rules of different factors on coil ambient temperature.Then,the heat insulation effects of insulation materials with different types,thickness and positions on the ambient temperature of induction coil are studied by numerical simulation.Finally,the heat insulation materials and arrangement methods which are most suitable for the EICAST system are obtained by experiments.Main conclusions are as follows:(1)Based on actual production conditions in a steel plant numerical simulation and experiments show that the ambient temperature of induction coil in the EICAST system is 796? after ladle baking at 1000? and containing moten steel at 1600? for 2 hours respectively,and the temperature reached 831? after steel teeming for 40min.(2)Steelmaking process parameters,nozzle block sizes and Fe-C alloy component can affect the ambient temperature of induction coil in the EICAST system.With the increase of the refining temperature of moten steel,the holding time of moten steel in ladle,the diameter of the nozzle brick casting hole and the thermal conductivity of Fe-C alloy and nozzle brick,the ambient temperature of induction coil rises.(3)Experiment results show that the ambient temperature of induction coil can be reduced by brushing heat insulation coating on the outer surface of the induction coil.With the increase of the coating thickness,the ambient temperature of induction coil decreases.When the thickness of heat insulation coating is 10mm the temperature of induction coil can reduced by 210?.(4)Heat insulation effects of different heat insulation materials are studied by numerical simulation.It is concluded that heat insulation coating and WDS insulation felt are suitable for induction coil in the EICAST system.When the thickness is 10mm,admirable heat insulation effect can be obtained while ensuring the strength of nozzle brick.(5)Ambient temperature of induction coil can be reduced by arranging the insulation layer in the outer surface and the upper surface of induction coil.However,when the insulating material layer is arranged above induction coil,the nozzle brick structure changes and the hot surface temperatures of heat insulation materials exceeds their limit temperatures.(6)After containing molten steel for 2.5h,ambient temperature of induction coil can be reduced to 635? after arranging 10mm insulation coating in the outer surface of the induction coil.And the temperature can be reduced to 610? when arranged 5mm insulation coating and 5mm WDS heat insulation felt Both the above two methods can achieve satisfactory results and meet the requirements of induction coil service life in the EICAST system.