LOW IRON LOSS HIGH MAGNET INDUCTION CRGO SILICON STEEL

Silicon steel also called Electrical steel which is an iron alloy which may have from zero to 6.5% silicon (Si:5Fe). Commercial alloys usually have silicon content up to 3.2% (higher concentrations result in brittleness during cold rolling). Manganese and aluminum can be added up to 0.5%.

Silicon increases the electrical resistivity of iron by a factor of about 5; this change decreases the induced eddy currents and narrows the hysteresis loop of the material, thus lowering the core loss by about three times compared to conventional steel. However, the grain structure hardens and embrittles the metal; this change adversely affects the workability of the material, especially when rolling. When alloying, contamination must be kept low, as carbides,sulfides,oxidesand nitrides, even in particles as small as one micrometer in diameter, increase hysteresis losses while also decreasing magnetic permeability. The presence of carbon has a more detrimental effect than sulfur or oxygen. Carbon also causes magnetic aging when it slowly leaves the solid solution and precipitates as carbides, thus resulting in an increase in power loss over time. For these reasons, the carbon level is kept to 0.005% or lower. The carbon level can be reduced by annealing the alloy in a decarburizing atmosphere, such as hydrogen.