0.35mm 0.5mm CRGO Electrical Steel Coils for Transformers

At GNEE, we specialize in supplying premium grain-oriented electrical steels to transformer manufacturers worldwide. Whether you need 0.35mm CRGO Electrical Steel for high-efficiency distribution transformers or 0.5mm CRGO Electrical Steel for larger power transformers, we provide the exact thickness, core loss (iron loss), and silicon content to optimize your core performance. Our 0.35mm and 0.5mm CRGO Electrical Steel coils help you reduce no-load losses, meet international energy standards (IEC, DOE, IEEE), and lower production costs.

 

 

0.35mm and 0.5mm Cold Rolled Grain-Oriented (CRGO) steel coils are specialized soft magnetic alloys, containing 0.5% to 4.5% silicon, used to form highly efficient magnetic cores in electrical transformers. The silicon content dramatically reduces electrical resistance and core energy losses.

Key Technical Specifications

• Thickness Range: 0.35 mm and 0.5 mm
• Material Type: Grain-Oriented Electrical Steel (CRGO)-optimized for high magnetic permeability and low power loss in a single rolling direction.
• Core Advantages: Low iron loss, high magnetic induction, smooth surface finish, and tight thickness tolerances.
• Applications: Power transformers, distribution transformers, large reactors, and magnetic shielding. 

 

 

 

When selecting 0.35mm or 0.5mm CRGO Electrical Steel for your transformer cores, three parameters dominate engineering decisions. Below we detail each with GNEE's guaranteed values.

 

Thickness Precision and Tolerance

• 0.35mm CRGO: Nominal 0.35mm ± 0.005 mm
• 0.5mm CRGO: Nominal 0.50mm ± 0.008 mm

We use laser micrometers to ensure consistent thickness across the entire coil width (600–1250 mm). Uniform thickness prevents air gaps in laminated cores.

 

Core Loss (Iron Loss) 

Core loss (W/kg) determines how much energy is wasted as heat in the transformer core. Lower is better. Our 0.35mm and 0.5mm CRGO Electrical Steel coils meet or exceed JIS C2553 and AISI standards.

Thickness	Core Loss at 1.5T, 50Hz	Core Loss at 1.7T, 50Hz	Typical Application
0.35mm	≤ 0.65 W/kg	≤ 0.95 W/kg	High-efficiency distribution transformers
0.5mm	≤ 0.85 W/kg	≤ 1.30 W/kg	Standard power transformers, reactors

 

 Silicon Content 

Silicon (Si) is the most important alloying element in electrical steel. It increases electrical resistivity, which reduces eddy current losses. However, too much silicon makes the steel brittle. Our 0.35mm and 0.5mm CRGO Electrical Steel maintains an optimal silicon range.

Element	Content (wt%)	Effect on Performance
Silicon (Si)	2.9% – 3.3%	Maximizes resistivity; reduces eddy current loss.
Carbon (C)	≤ 0.003%	Prevents magnetic aging.
Manganese (Mn)	0.03 – 0.10%	Combines with sulfur to prevent hot cracking.
Sulfur (S)	≤ 0.001%	Minimized to avoid grain boundary weakening.
Phosphorus (P)	≤ 0.015%	Controlled to maintain ductility.
Aluminum (Al)	0.005 – 0.015%	Acts as a deoxidizer and grain refiner.

 

Why 2.9-3.3% Silicon?

This range provides the best trade-off: electrical resistivity of ~47 µΩ·cm (compared to 10 µΩ·cm for low-carbon steel) while maintaining sufficient ductility for stamping and slitting.

 

 

Grade	Yeild Strength (N/mm2)	Ultra -Tension Strength (N/mm2)	Ductility (%)	Hardness (HV1
M35W230	430	560	20.0	225
M35W250	415	550	20.5	220
M35W270	400	515	20.5	215
M35W300	360	480	21.5	195
M35W360	350	480	23.5	190
M35W440	275	420	27.5	165
M35W550	265	415	33.5	160

 

 

Both thicknesses are used across the electrical grid. Here's where our customers deploy 0.35mm and 0.5mm CRGO Electrical Steel coils:

• Oil-immersed distribution transformers (10kV–35kV): 0.35mm preferred for low no-load loss.
• Dry-type transformers (up to 2.5 MVA): 0.35mm reduces audible noise.
• Large power transformers (110kV–500kV): 0.5mm for cost-effective performance.
• Reactor cores for VFDs and HVDC systems: 0.5mm handles DC bias better.
• Current transformers (CT) and potential transformers (PT): 0.35mm for high accuracy.
• Traction transformers for electric railways: 0.35mm for vibration resistance.

 

 

 

With over 18 years of exporting electrical steels, GNEE provides Experience, Expertise, Authoritativeness, and Trustworthiness (EEAT) in every shipment.

 

Factory Direct Sourcing

We partner with Baowu, Shougang, and TISCO – China's top CRGO mills. Every 0.35mm and 0.5mm CRGO Electrical Steel coil is traceable to its original heat number.

 

Quality Control Before Shipping

Our QC team performs:

• Core loss test using Epstein frame (IEC 60404-2)
• Thickness check at 5 points across the width
• Surface insulation resistance test (ASTM A717)
• Flatness inspection – max camber 2mm per 2m length

Professional Packaging for International Transport

To prevent rust and edge damage during sea freight, we pack every coil with:

• VCI (Volatile Corrosion Inhibitor) paper inner wrap
• Moisture-proof kraft paper
• Galvanized steel outer shell
• Wooden pallets with ISPM 15 fumigation stamp

 

Flexible Supply Options

• MOQ: One 20-foot container (approx. 25 tons) or trial order of 10 tons
• Lead time: 7 days for slit coils; 15 days for standard widths
• Payment: LC at sight, TT, or DP
• Slitting service: We cut to widths from 20mm to 1250mm per your drawing

 

 

Conclusion: Choose the Right 0.35mm or 0.5mm CRGO Electrical Steel Coil for Your Next Transformer Project

Whether you need the ultra-low core loss of 0.35mm CRGO Electrical Steel for high-efficiency transformers or the cost-optimized performance of 0.5mm CRGO Electrical Steel for larger power units, GNEE has the stock, technical data, and global shipping experience to support you. Our guaranteed silicon content (2.9-3.3%), precise thickness control, and certified core loss values ensure your transformers meet the most demanding energy standards.

Ready to test our material?
👉 Click the "Send Inquiry" button now to request free samples of both 0.35mm and 0.5mm CRGO Electrical Steel coils, receive a mill price list, or schedule a video tour of our warehouse. Tell us your target core loss and lamination width – we will reply with a datasheet and quotation within 4 hours.

Don't guess your core loss – let GNEE deliver the exact CRGO electrical steel you need.