Thin cold rolled iron-silicon steel made for the magnetic cores of electrical machines. Grain-oriented (GO, CRGO) steel has its crystals aligned in the rolling direction and gives the lowest losses in transformers; non-oriented (NGO, CRNGO) steel has similar properties in every direction and is used in rotating machines. Grades are identified by their guaranteed core loss.
Silicon — up to about 3.5 % — raises the electrical resistivity of iron and so cuts the eddy-current losses in a core that carries alternating magnetic flux; the steel is also made very low in carbon and other impurities and rolled thin, because losses rise with thickness. The sheet is coated on both sides with a thin insulating layer so that stacked laminations do not conduct to each other. Electrical steel is bought by its magnetic properties — core loss in W/kg at a stated flux density and frequency, and permeability — rather than by strength.
Grain-oriented steel is processed so that almost all its crystals have the same orientation, with an easy direction of magnetisation along the rolling direction. Its losses in that direction are very low, which suits transformer cores where flux runs along the limbs. Conventional (CGO) and high-permeability (HGO, HiB) grades exist, and domain-refined grades, scribed by laser, have the lowest losses. Production is complex and concentrated among relatively few producers worldwide.
Non-oriented steel is used where the flux direction rotates — motors, generators, alternators, compressors and electric-vehicle traction motors. It is supplied fully processed (annealed by the mill, ready to punch) or semi-processed (the user anneals the punched laminations). Thin, high-silicon NGO grades for high-frequency EV motors are the fastest-growing part of the market.
European names state the loss directly: M400-50A is a non-oriented grade with at most 4.00 W/kg at 1.5 T and 50 Hz, 0.50 mm thick, fully processed (A); M111-30P is a high-permeability grain-oriented grade, 1.11 W/kg at 1.7 T, 0.30 mm. Chinese and Japanese mills use designations such as 50W470 and 30Q120. In the Middle East electrical steel is used by transformer and motor manufacturers and by lamination service centres; nearly all of it is imported.
Electrical steel is sold in coils, slit to the widths of the lamination presses or core-cutting lines, and as cut laminations and wound cores from service centres. The insulation coating (organic, inorganic or mixed, or the mill glass film and phosphate coating on GO) is specified with the grade.
| Region | Standard | What it covers |
|---|---|---|
| Europe | EN 10106 CEN-CENELEC |
Cold rolled non-oriented electrical steel strip and sheet delivered in the fully processed state |
| Europe | EN 10107 CEN-CENELEC |
Grain-oriented electrical steel strip and sheet delivered in the fully processed state |
| Europe | EN 10126 / EN 10165 CEN-CENELEC |
Cold rolled electrical steel sheet and strip delivered in the semi-processed state — non-alloy and alloyed |
| International | IEC 60404-8-4 | Magnetic materials — cold-rolled non-oriented electrical steel strip and sheet delivered in the fully processed state |
| International | IEC 60404-8-7 | Magnetic materials — cold-rolled grain-oriented electrical steel strip and sheet delivered in the fully processed state |
| USA | ASTM A677/A677M ASTM |
Non-oriented electrical steel, fully processed types |
| USA | ASTM A876/A876M ASTM |
Flat-rolled, grain-oriented, silicon-iron, electrical steel, fully processed types |
| Japan | JIS C2552 JSA |
Cold-rolled non-oriented electrical steel strip delivered in the fully processed state |
| Japan | JIS C2553 JSA |
Grain-oriented electrical steel strip |
| China | GB/T 2521 SAC |
Fully processed cold-rolled electrical steel strip — Part 1 non-oriented, Part 2 grain-oriented |
Grade equivalents and the standards bodies: Steel grades & standards
No open offers or inquiries for this product right now.
Translation isn’t available right now. The site is shown in English.
Loading translation…
