Silicon steel is an alloy of iron and silicon that has important magnetic properties.
Silicon steel, also known as electrical steel, is a very low carbon alloy (less than .005%) that is used in motor and transformer laminations. It is characterized by lower core loss properties and higher magnetic permeability than carbon steels. There are a number of grades that include both grain-oriented and “NGO” (non-grain-oriented) versions. The standard thicknesses are .007, .014, .0185 and .025 inches. Silicon steels are often produced with an electrically insulating coating known as coreplate, which eliminates the need to interleave laminations with dielectric material.
Grain-oriented electrical steel has a uniform, consistent direction of grains in its structure which allows for greater flux density and magnetic saturation. Most commonly, grain-oriented electrical steel is used for transformers which have a predictable and specific magnetic field direction.
Grain oriented electrical steels (GOES) are iron-silicon alloys that were developed to provide the low core loss and high permeability required for efficient and economical electrical transformers. GOES is the most energy efficient electrical steel and used in transformers where energy conservation is critical.
We have been a global innovator in the most efficient GOES products, since first inventing and introducing them in 1926. GOES is a critical material to the well-being of our electric grid. As the only domestic producer of GOES, we have the dedicated equipment, advanced manufacturing processes, and experienced employees to keep our homes and businesses powered.
Non-oriented electrical steels are iron-silicon alloys in which magnetic properties are practically the same in any direction in the plane of the material. Standard grades are available, with the advantages of our proprietary DI-MAX® processing that enhance our product's magnetic properties. Material is available fully and semi-processed, depending on the grade.
DI-MAX grades have superior permeability at high inductions, low average core loss, and good gauge uniformity. In addition, cold finishing plus strip annealing produces a smooth surface resulting in excellent flatness and a high stacking factor. Applications include high-efficiency motors, large and small transformers, generators, lighting ballasts and ignition coils.
Non-grain-oriented strip is annealed in a radiant tube furnace using a continuous process after cold rolling to ensure recrystallization and controlled grain growth. Top-quality steel requires strip temperatures above 1100°C and a very dry atmosphere with a high hydrogen content. This is followed by controlled cooling to obtain an extremely flat strip.
When low carbon steel is alloyed with small quantities of silicon, the added volume resistivity helps to reduce eddy current losses in the core. Silicon steels are probably of the most use to designers of motion control products where the additional cost is justified by the increased performance. These steels are available in an array of grades and thicknesses so that the material may be tailored for various applications. The added silicon has a marked impact on the life of stamping tooling, and the surface insulation selected also affects die life. Silicon steels are generally specified and selected on the basis of allowable core loss in watts/lb.
The grades are called out, in increasing order of core loss by M numbers, such as M19, M27, M36 or M43, with each grade specifying a maximum core loss. (Note that this means that material can be substituted up , as M19 for M36, but not vice versa.) The higher M numbers (and thus higher core losses) are progressively lower cost, although only a few percent is saved with each step down in performance. M19 is probably the most common grade for motion control products, as it offers nearly the lowest core loss in this class of material, with only a small cost impact, particularly in low to medium production quantities. In addition to grade, there are a number of other decisions to make regarding silicon steels. These are:
1. Semi vs. Fully processed material, 2. Annealing after stamping,3. Material Thickness,4. Surface insulation.
Fully processed material is simply material which has been annealed to optimum properties at the steel mill. Semi processed material always requires annealing after stamping in order to remove excess carbon as well as to stress relieve. The better grades of silicon steel are always supplied fully processed while semi processed is available only in grades M43 and worse. The designer considering semi processed M43 should evaluate Low Carbon Steel which may provide equivalent performance at lower cost.
Many types of electrical devices use a soft magnetic material as the flux-carrier. Silicon-iron (Si-Fe), often referred to as “electrical steel” is the most commonly used material for motors, generators, transformers, and inductors.
High permeability, low coercivity, and ductile properties make Arnold’s Grain Oriented (GOES) and Non Grain Oriented (NGOES) Silicon Steels a perfect match for your high speed, high efficiency motors and transformers applications. Each type of Silicon Steel is available in a variety of thicknesses and widths. Both types have particular advantages over alternative materials for a range of applications. When optimally applied to a particular application, each type offers more efficient use of electrical steel, resulting in higher power density and energy savings.
Material: silicon steel Width: 20 – 1,250 mm Length: 40 – 6,000 mm Material thickness: 0.18 – 0.5 mm Feeding precision: 0.1 mm Speed: 240 m/min Capacity: up to 180 sheets/min 18” wide multi-touchscreen
Material: silicon steel / Width: 20 – 1,250 mm slit coils/ 0.18 – 0.5 mm Width precision: 0.1 mm
Silicon Steel :
1. The thickness is 0.025 mm against CRGO silicon sheet steel thickness 0.23-0.3 mm. Lesser in thickness in sheet results in lower eddy current loss
2. Random molecular structure of amorphous metal causes less friction than CRGO when a magnetic field is applied. This allows easy magnetization and demagnetization significantly lowers hysteresis losses, thus amorphous core significantly reduces core losses which is about 65-75%
3. Saves energy and therefore reduces greenhouse gases and other pollution
4. Excellent option to reduce distribution losses and improve efficiency
5. Superior electrical performance under harmonic condition. Possible to improve power quality and mitigate harmonics
6. Lower temperature rise, slower deterioration of insulations and hence longer life
7. Increase in use of power electronics has resulted in considerable amount of higher harmonics distortion in electrical power system. Higher frequency harmonics lead to increase in transformer core losses whereas amorphous alloy provides lower loss under high frequency
8. Easy for repair and replacement of coils