Oriented elctrical steels are iron-silicon alloys that were developed to provide the low core loss and high permeability required for more efficient and economical electrical transformers. First produced commercially by AK Steel, these magnetic materials exhibit their superior magnetic properties in ther rolling direction. This directionality occurs because the steels are specially rpocessed to create a very high production of grains within the steel which have similarily oriented atomic crystalline structures to the rolling direction.

In iron-silicon alloys, this attomic structure is cubic and the crystals are most easily magnetized in a direction parallel to the cube edges. By a combination of precise steel composition, the crystals of these oriented electrical steels are aligned with their cube edges nearly parallel to the direction in which the steel is rolled. Consequently, they provide superior permeability and lower core loss when magnetized in this direction. This phenomenon is clearly illustrated by figure 3 which shows the polydirectional permeability of AK Steel Oriented Electrical Steels.

AK Steel Oriented Electrical Steels are used most effectively in transformer cores having wound or sheared and stamped laminations with the magnetic flux path entirely, or predominately, in the rolling direction. They also are used in large generators and other appartus when the design permits the directional magnetic characteristics to be used efficiently. Since the inception of oriented grades in 1933, AK Steel Research has continued to develope new and imprvoed grades to provide the eloectrical industry with core materials for the manufacture of most efficient electrical apparatus.