Since pure iron is limited because its high eddy current losses, by incorporating small quantities of other elements in iron good magnetic properties are obtained. The chief alloying constituent is silicon which is added to iron in amount of about 0.5 to 5% by weight. Extensive use is made of iron silicon alloy usually called silicon steel for relatively strong alternating magnetic fields. It is generally used in transformers, electrical rotating machines, Reactors, Electromagnets and relays. Silicon sharply increases the electrical the resistivity of iron thus decreasing the iron losses due to eddy current. It raises the permeability at low and moderate flux densities. Adding up of silicon to iron decreases the hysteresis loss. The magnetostriction effect is also decreased.

APPLICATIONS: These alloys are used in greatest quantity in power transformers motors, generators, relays and receivers.