General Description of Electromagnetic Stirrer (EMS)

Complete Electromagnetic stirrer (EMS) System
Electromagnetic Stirrer (EMS) is regularly used on CCM (continuous casting machine of bloom/billet), installed in the mould, strand or final. Most EMS are installed outside or inside the mould, which depends on the conditions of caster. You can also use Mould-EMS + Final EMS together to achieve a better metallurgical effects.
An inductive Electromagnetic Stirrer is the stator of an asynchronous motor, the rotor of which is the liquid core of the continuously cast product in CCM. This stator produces either a rotating or a traveling magnetic induction field, which induces eddy current perpendicular to magnetic field. The stirrer creates mobile magnetic fields, which penetrate into the liquid steel, and creates eddy current. The magnetic induction field and the eddy current combine to create an electro-magnetic force, which causes the stirring motion in the liquid steel. During cooling and solidification of liquid steel, columnar dendrites are formed which are oriented along the direction of temperature gradient. This causes central segregation and inter-columnar cracking when the solid shell is subjected to tensile strains during solidification. Electro-magnetic stirring of liquid steel facilitates quicker dissipation of superheat and the formation of an equi-axed structure in the cast product. Stirring of liquid pool will improve the internal structure due to better heat transfer between solidification front and liquid metal pool. The equi-axed zone in the cast product will increase whereas the central segregation will reduce. It will also help in reduction of breakouts during operation of CCM due to better dissipation of heat.
EMS consists of EMS coils, electric controll system and cooling water system. Electrica l control system consists of remote IPC, local control cabinet (PLC) and frequency converters.

Complete EMS System Configuration Diagram

Technical Features of KEMEIDA Electromagnetic Stirrer(EMS)
*A new algorithm has been developed by KEMEIDA and GL Electromagnetic Field Software Co., names AGILD EM STIRRING ALGORITHM, which uses New Strip Magnetic Field Differential Integral Equation.
*This software can design electromagnetic parameters optimized. EMS shall be with high magnetic induction and stirring force. So stirring effect shall be great.
*Stirring force can be calculated by this software according different freq and current. So the best freq and current can be provided for user to test & choose.
*Optimized design shall be done for L/D. Iron Core length shall be increased properly. So stirring effect shall be improved.
*KEMEIDA EMS uses low voltage and large current, which can avoid damage to insulation. It shall make reduce current leakage and prolong EMS life.
*Put EMS lower in the mould properly to make magnetic field around meniscus as little as possible to ensure strong magnetic field.

AGILD MAGNETIC FIELD VIRTUAL DIAGRAM

ROTATING MAGNETIC FIELD DISTRIBUTION DIAGRAM