Silicon Steel Coil (Electrical Steel)
Silicon steel coil, commonly known as electrical steel, is a cold-rolled specialty steel alloyed with silicon to reduce core loss and improve magnetic permeability in electromagnetic devices.
Material
Silicon Steel (Electrical Steel). Representative non-oriented grades include Baosteel B20R065, B23R075; ArcelorMittal HP75D, HP80D; JIS 50C800. Grain-oriented grades include various Hi-B and conventional grades.
Model
CRNO Coil, CRGO Coil
Size
Standard widths range from 600 mm to 1300 mm, with 1200 mm being highly common for transformer and motor applications.
Thickness
0.18 mm to 0.65 mm for most electrical grades, with common specifications at 0.23mm, 0.27mm, 0.35mm, and 0.50mm.
Standard
IEC 60404-8-4, IEC 60404-8-7; ASTM A677, A876; JIS C 2552, C 2553; GB/T 2521, GB/T 3655.
MOQ
10 Metric Tons.
Delivery Time
Standard lead time is 6 to 10 weeks from order confirmation due to specialized production scheduling.
Long Description
Silicon steel coil is a precision-engineered ferromagnetic material produced by adding silicon (typically 0.5% to 3.5%) to low-carbon steel, which is then cold-rolled and annealed to achieve specific magnetic properties. The silicon increases electrical resistivity, reducing eddy current losses, and decreases magnetostriction, lowering audible noise. This product category is divided into two primary types: Cold-Rolled Non-Oriented (CRNO) and Cold-Rolled Grain-Oriented (CRGO). CRNO has uniform magnetic properties in all directions and is used in rotating machinery, while CRGO has highly directional magnetic properties optimized for the rolling direction and is used in transformer cores. The manufacturing process involves tight control of chemistry, insulation coating application, and thermal treatment to guarantee low core loss (W/kg) and high magnetic induction.
Key Product Highlights
Silicon steel coil is engineered for low core loss and high magnetic permeability to maximize energy efficiency.
It is available in non-oriented (CRNO) and grain-oriented (CRGO) types for different electromagnetic applications.
The surface is treated with an inorganic insulation coating to minimize interlaminar losses.
Precise gauge control and excellent flatness are critical for high-speed stacking and winding operations.
Material specifications are primarily defined by maximum core loss (e.g., W/kg @ 1.5T/50Hz) and thickness.
Product Advantages
Consistent magnetic properties across the coil ensure predictable performance in final electrical devices.
The insulation coating provides good weldability, corrosion resistance, and interlaminar resistance.
Supplied to international (IEC, ASTM) and regional (JIS, GB) standards with full magnetic property certification.
Available in a range of thicknesses and grades to optimize the cost-performance ratio for specific applications.
Specialized packaging protects the sensitive surface finish and ensures material arrives in optimal condition.
Industry Application
This coil is the core material for manufacturing laminated and wound cores of electric motors, generators, power transformers, distribution transformers, chokes, relays, and other electromagnetic components.
Technical Specifications
| Parameter | Unit | Non-Oriented (CRNO) | Grain-Oriented (CRGO) | Notes |
|---|---|---|---|---|
| Carbon Content (C) | % | ≤ 0.005 | ≤ 0.005 | Ultra-low carbon to minimize magnetic aging. |
| Manganese (Mn) | % | 0.10 – 0.50 | 0.05 – 0.15 | Varies by specific grade and producer. |
| Phosphorus (P) | % | ≤ 0.030 | ≤ 0.020 | Typically controlled at low levels. |
| Sulfur (S) | % | ≤ 0.005 | ≤ 0.005 | Very low to improve magnetic properties. |
| Tensile Strength | MPa | 350 – 500 | 300 – 450 | Not the primary specification; varies with temper. |
| Yield Strength | MPa | 280 – 400 | 250 – 350 | Not the primary specification. |
| Elongation | % | 20 – 35 | 15 – 25 | Important for punchability and formability. |
| Hardness | HV | 120 – 180 | 110 – 160 | Vickers hardness typical. |
| Thickness | mm | 0.18 – 0.65 | 0.18 – 0.35 | Thinner gauges for higher frequency/lower loss. |
| Width | mm | 600 – 1300 | 800 – 1300 | CRGO often in narrower ranges for core winding. |
| Coil Weight | MT | 3 – 10 | 3 – 8 | Lighter than carbon steel due to thinner gauge. |
| Surface Treatment | – | Insulation Coating (C3, C4, C5) | Insulation Coating (C0, C3, C5) | Inorganic or semi-organic coating for interlaminar resistance. |
| Coating / Finish | – | Uncoated, C-type coating | Glass Film, Stress Coating + Glass Film | CRGO has a distinctive glass film coating. |
| Rolling Type | – | Cold Rolling | Cold Rolling + Special Annealing | CRGO involves secondary recrystallization annealing. |
| Standard Example | – | IEC 60404-8-4 M235-35A | IEC 60404-8-7 27MOH | Representative international standard designations. |
Packaging & Surface Treatment
Coils are packaged with exceptional care to prevent edge damage, coil collapse, and surface contamination. Standard practice includes winding on a sturdy steel or cardboard core, interleaving with protective paper or plastic, wrapping in multiple layers of moisture-proof VCI paper and heavy-duty plastic film, and securing on wooden cradles with reinforced edge protectors. The surface features a specialized insulation coating (e.g., C-3, C-4, C-5 for CRNO; glass film for CRGO) which is integral to the product’s function and is protected during packaging.
Aliases Names
Electrical Steel Coil, CRNO Coil, CRGO Coil, Lamination Steel, Transformer Steel, Dynamo Steel.
