Silicon Electrical Steel Buying Guide: CRGO vs CRNGO — How to Specify Transformer Core Steel by Grade, Thickness, and Core Loss
Silicon electrical steel — thin steel alloyed with silicon to cut magnetic losses — is the core material inside every transformer, motor, and generator. The grade decides how much energy the core wastes as heat; the thickness decides eddy-current loss; the coating decides whether laminations punch cleanly and stack without shorting. Specify the wrong loss class and the transformer fails its efficiency test, or order non-oriented steel for a distribution transformer core and throw away margin on every unit.
This guide compares CRGO vs CRNGO, the grades buyers quote, thicknesses, coatings, standards, and a complete RFQ checklist.
CRGO vs CRNGO
| Aspect | CRGO (grain-oriented) | CRNGO (non-oriented) |
|---|---|---|
| Grain | Oriented (Goss texture) | Random |
| Loss direction | Lowest along rolling direction | Similar all directions |
| Use | Transformers (power/distribution) | Motors, generators, small transformers |
| Typical grades | M3–M6 / 23–35QG | M270–M800 / 35W–50W |
| Cost | Higher | Lower |
Grades Explained (What the Numbers Mean)
- CRNGO M-grades (e.g., M270-35A): max core loss in W/kg (2.70) + thickness in 0.01 mm (0.35).
- CRGO M-grades (e.g., M4): loss class ranking — lower M number, lower loss.
- Chinese grades: 35W250, 50W470 (thickness + loss); QG/QH series for oriented.
- Always quote max core loss at the test induction/frequency (e.g., P1.5/50), not just the trade name.
Thickness Guide
| Thickness | Loss | Use |
|---|---|---|
| 0.23 / 0.27 mm | Lowest | High-efficiency transformers |
| 0.30 / 0.35 mm | Standard | Distribution transformers, motors |
| 0.50 mm | Higher | General motors, economy cores |
| 0.65 mm | Highest | Small/legacy machines only |
Coating and Surface
- C2/C3 inorganic: punchability and interlaminar insulation for stacked cores.
- C5/C6 inorganic-organic: higher insulation resistance, weldable laminations.
- Tension coating (CRGO): improves loss via surface tension — handle carefully to avoid scratching.
Standards Buyers Quote
- IEC 60404: magnetic materials classification and test methods.
- ASTM A677 / A683: US non-oriented and oriented grades.
- EN 10106 / 10107: European non-oriented / oriented sheet.
- GB/T 2521: Chinese grain-oriented grades.
Common Applications
- Power and distribution transformers (CRGO).
- EV traction and industrial motors (CRNGO thin gauge).
- Generators, reactors, ballasts.
- Audio and instrument transformers.
RFQ Checklist
- Type: CRGO or CRNGO
- Grade: M-grade / W-grade + max core loss + test condition
- Thickness (mm) and width (coil or slit)
- Coating: C2 / C3 / C5 / tension coating
- Form: coil / slit coil / cut laminations
- Quantity, test certs, destination / Incoterm
FAQ
CRGO or CRNGO for my transformer? CRGO for wound/stacked power cores; CRNGO only for small low-duty units.
0.23 or 0.30 mm? 0.23 for premium efficiency tiers; 0.30 the cost-balanced default.
Why did my core test fail? Usually wrong loss class ordered, burred punch edges shorting laminations, or degraded tension coating — check all three.
Why Source Electrical Steel from Yihang Metal
Yihang Metal supplies CRGO and CRNGO coils, slit coils, and cut laminations to IEC 60404, ASTM, EN, and GB standards, in 0.23–0.65 mm gauges with C2/C3/C5 and tension coatings, each lot certified for core loss and magnetic induction. Standard grades typically ship in 25–35 days.
Ready to specify your electrical steel? Send us the type, grade, loss requirement, thickness, and coating, and we will confirm mill availability and lead time with a fixed-price quote and test certificate. Email [email protected] or use the quote form on this page — our team replies within one business day.