Electrical steel is usually coated to increase electrical resistance between laminations, reducing eddy currents, to provide resistance to corrosion or rust, and to act as a lubricant during die cutting. There are numerous coatings, organic and inorganic, and the coating used depends on the implementation of the Non Grain Oriented Steel. The type of coating selected depends on the heat treatment of the laminations, whether the finished lamination is going to be immersed in oil, and the working temperature of the finished apparatus. Very early practice was to insulate each lamination with a layer of paper or a varnish coating, but this reduced the stacking factor of the core and limited the maximum temperature of the core.
The magnetic properties of electrical steel are influenced by heat treatment, as enhancing the average crystal size decreases the hysteresis loss. Hysteresis loss is determined by a standard test and, for common grades of electrical steel, may range from a couple of to 10 watts per kilogram (1 to 5 watts per pound) at 60 Hz and 1.5 tesla magnetic field strength.
Electrical steel could be delivered in a semi-processed state in order that, after punching the ultimate shape, one final heat treatment can be applied to make the normally required 150-micrometer grain size. Fully processed electrical steel is usually delivered with an insulating coating, full heat treatment, and defined magnetic properties, for applications where punching does not significantly degrade the electrical steel properties. Excessive bending, incorrect heat treatment, or even rough handling can adversely affect electrical steel’s magnetic properties and may also increase noise because of magnetostriction.
The magnetic properties of Gi Wire are tested utilizing the internationally standard Epstein frame method. Practical aspects
Electrical steel is a lot more costly than mild steel-in 1981 it was more than twice the price by weight. How big magnetic domains in sheet electrical steel may be reduced by scribing the top of the sheet using a laser, or mechanically. This greatly cuts down on the hysteresis losses within the assembled core.
Grain oriented Electrical Steel CRGO is undoubtedly the most important soft magnetic material in use today. Wheather in small transformer, distribution transformer or perhaps in large transformer & generator, grain oriented electrical steel CRGO is a must for the production of economical electrical machines.
Grain oriented Electrical Steels are iron-silicon alloys which provide low core loss and permeability necessary for more effective and economical electrical transformers. CRGO Grain oriented grades of electrical steel are generally used for transformer cores and large generators.
Non-oriented Electrical steel CRNGO fully processed steels are iron-silicon alloys with varying silicon contents and possess similar magnetic properties in all directions in plan from the sheet. Non-oriented Electrical wnhsva are principally used for motors, generators, alternators, ballasts, small Transformers and a variety of other electromagnetic applications.
The earliest soft magnetic material was iron, which contained many impurities. Researchers learned that incorporating silicon increased resistivity, decreased hysteresis loss, increased permeability, and virtually eliminated aging.
Substantial quantities of Grain oriented Electrical steel CRGO are employed, mainly in power and distribution transformers. However, it has not
supplanted Electrogalvanized Steel Coil, which is used extensively in which a low-cost, low-loss material is needed, specifically in rotating equipment. Mention should also be made of the relay steels, used widely in relays, armatures, and solenoids. Relay steels contain 1.25 to 2.5% Si, and they are utilized in direct current applications because of better permeability, lower coercive force, and freedom from aging.