Electromagnetic stirrer (EMS) In principle, electromagnetic stirrer (ems) can be regarded as a rotary motor stator and liquid steel as rotator. Ems is placed lower in the mould to make the liquid metal rotate in the mold. The magnetic field penetrates the copper mould tube, stainless steel baffle tube, and any solidified shell and gives rise to induced currents in the melt. These interact with the traveling magnetic field and create a torque on and by that a movement of the molten steel. General speaking, ems can be usually placed in one of three locations (refer to drawing below): Ems locaction 1. Mould electromagnetic stirrer (mems): ems is mounted outside copper tube. 2. Strand electromagnetic stirrer (sems): ems is mounted outside billet. 3. Final electromagnetic stirrer (fems): ems is mounted outside billet. We seldom use the second mode now, but usually use the first or the third one, or use the two sorts in the same time.The metallurgical effects differ from different locations. Metallurgical effects Stirrer location Metallurgical effects Steel variety Mems 1. Increase equiaxed zone. 2. Decrease air holes under surface. 3. Improve the central porosity and segregation Low alloy steel Spring steel Cold rolled steel Medium, high carbon steel Sems 1. Increase equiaxed zone 2. Decrease inner cracks 3.Improve the central segregation, shrinkage and porosity Stainless steel Tool steel Fems 1. Improve equiaxed zone 2. Improve central segregation, porosity and shrinkage