What is Electric Steel?

Electric steel is made from silicone to help retain heat.

Electrical steel is an alloy that contains iron and silicon. It can be made with 15% silicon, depending on what the final product will look like. Also called transformer steel, this type of steel is often used to build transformer cores as well as generator and motor stators. It is also efficient at retaining heat, so high temperatures do not affect the performance of items such as power lines and manufacturing machinery, where keeping temperatures low is important for energy efficiency and equipment longevity.

Heat loss in electrical steel is avoided because of entrained silicon. This increases what is known as resistivity within the steel, which prevents magnetic eddy currents that cause exhaust heat to build up. Performance is also improved when larger grain sizes are used to produce silicon steel. Heat treatment of steel during production fulfills the task of creating a larger grain size.

The grain structure itself can be oriented to suit certain tasks. In grain-oriented silicon steel, all grains point in one direction, which means that the molecules are facing the same polar orientation. A stable magnetic field is produced by electrical steel, making it safe for use in power transformers and other applications where stable electromagnetism is important. When the required magnetic properties need to be less structured, unoriented silicon steel can be used, such as in motors or generators.

Electric steel is sold in degrees, each defined by the level of heat loss from the core. An example of this type is the M19, where this loss is relatively low, making the material suitable for use in motion control systems. Higher loss steels are offered in grades such as M43 which are not necessarily heat treated, or annealed, to relieve stresses in the material caused by the production process.

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The performance of electrical steel is improved through insulation. An oxide coating can be applied during milling, and while this is the cheapest way to insulate steel, the coating does not withstand stress very well. Enamel or varnish coatings offer the advantage of good insulating properties, but heat treatment is not possible after the product has been manufactured. High-grade coatings are more versatile and withstand high temperatures, but if the insulation is strong enough, it can cause excessive wear and tear on the tools used to process the steel.

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