What is grain‑oriented silicon steel?
Grain oriented silicon steel (CRGO) is the magnetic heart of every power transformer. Its crystals align in one direction. Furthermore, that alignment lets magnetic flux flow with minimal resistance. At Jiangsu Zhongtong Weiye Special Steel Co., Ltd., we supply CRGO grades M3, M4, and M5. Here is the plain-language guide.
Why Crystal Orientation Matters
During cold rolling and annealing, the grains grow into a Goss texture {110}<001>. Consequently, magnetic flux flows 3–5 times more easily along the rolling direction. Furthermore, it faces high resistance across the sheet. Transformers have unidirectional flux. Consequently, CRGO matches the flux path perfectly.
Key Properties
| Property | Value | Why it matters |
|---|---|---|
| Silicon content | ~3% | Raises resistivity, cuts eddy loss |
| Core loss | 0.7–1.5 W/kg | Low wasted heat |
| Permeability | High along rolling | Compact core design |
| Thickness | 0.23–0.35 mm | Cuts eddy currents |
| Magnetostriction | Low | Quieter transformers |
How It Is Made
Production follows four steps:
- Hot roll the slab to ~2.0 mm.
- Cold roll to final thickness in stages.
- Intermediate anneal between rolls.
- Final high-temp anneal grows the Goss grains.
Furthermore, a phosphate insulation coating goes on last. Consequently, each lamination is electrically isolated from the next.
Where CRGO Goes
CRGO is the right choice for:
- Power transformers (220 kV and above).
- Distribution transformers.
- HVDC converter transformers.
- Reactors and inductors.
Consequently, wherever flux flows one way at 50/60 Hz, CRGO wins.
CRGO vs CRNGO at a Glance
| Factor | CRGO | CRNGO |
|---|---|---|
| Grain direction | Along rolling | Random |
| Best for | Transformers | Motors, generators |
| Core loss | Very low | Medium |
| Cost | Higher | Lower |
| Flux direction | One way | All directions |
Consequently, motors use CRNGO because flux rotates. Transformers use CRGO because flux is steady.
Grade Selection
| Grade | Core loss (W/kg @1.7T) | Typical use |
|---|---|---|
| M3 | ~0.70 | Premium grid transformers |
| M4 | ~0.85 | Standard power transformers |
| M5 | ~1.05 | Distribution transformers |
We supply M3 Grain Oriented Electrical Steel, M4 Grain Oriented Electrical Steel, and M5 Grain Oriented Electrical Steel.
Design Tips
Always align the rolling direction with the main flux path. Furthermore, use step-lap joints at corners to reduce local saturation. Consequently, the core runs cooler and quieter.
What We Supply
We ship CRGO coil:
- Grades: M3, M4, M5.
- Thickness: 0.23–0.35 mm.
- Slit to core width with ±0.05 mm tolerance.
- Coil ID 508 mm or 406 mm.
Furthermore, we pack for ocean freight with VCI paper.
Specify Your CRGO Grade
Tell us your transformer kVA and voltage class. We will recommend the correct grade and quote.
- Email: vera.liang@ztwysteel.com
- Location: Xishan District, Wuxi, Jiangsu, China
- Supply range: CRGO grain-oriented steel, CRNGO non-oriented steel, slit strip
- Slitting tolerance: ±0.05 mm
- Documentation: MTC with core loss, thickness, width, and insulation coating
We reply within one working day.
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