Grain Oriented Silicon Steel (CRGO) is the go-to material for transformer cores. With a silicon content of 0.8% to 4.8%, this soft magnetic material offers exceptional magnetic permeability, making it a critical component in building efficient magnetic circuits for transformers.
Transformer Core
Why Use Grain Oriented Silicon Steel in Transformers?
Transformers operate under alternating magnetic fields, which lead to core losses—mainly hysteresis loss and eddy current loss. CRGO features a very narrow hysteresis loop, requiring less energy to magnetize, thus significantly reducing hysteresis loss and unwanted heat generation.
Transformer alternating magnetic field
To reduce eddy current loss, transformer cores are built using insulated lamination stacks of CRGO sheets, typically between 0.18mm and 0.30mm thick. This laminated structure increases electrical resistance along eddy current paths, minimizing energy loss. Additionally, CRGO’s naturally high resistivity further suppresses eddy currents.
Core insulation laminated structure
Popular Grades and Their Applications
The current mainstream transformer core materials are high-performance cold-rolled grain oriented silicon steels. Common Baosteel grades include:
20/065, 20/075, B23R080 – Ideal for high-end transmission transformers
B27R095, B30R120 – Widely used in distribution transformers
Internationally recognized grades also dominate the market:
Japan (JFE): HI-B® series
Germany (ThyssenKrupp): M130-27P
USA (AK Steel): AK SURA®
MOOPEC offers expert material selection and customization based on client application needs.
Manufacturing Advancements in CRGO
Unlike earlier hot-rolling processes, today’s transformer-grade CRGO is produced via cold rolling, using a single cold-rolling and double-annealing process. Advanced techniques like decarburization annealing and nitriding treatment are applied to ensure grain alignment, magnetic uniformity, and refined domain structure.
Technological process
MOOPEC has the capability to stably supply ultra-thin CRGO sheets in 0.18mm, 0.20mm, and 0.23mm, providing strong performance advantages for high-efficiency, high-frequency transformer designs.
Key Material Properties of High-Quality CRGO
Oriented silicon steel laminated sheets
Low Core Loss: Lower iron loss improves transformer efficiency
High Magnetic Induction: Enables compact core design
Excellent Lamination Performance: Uniform thickness and flat surfaces enhance assembly quality
Stable Insulation Coating: Strong adhesion and high corrosion resistance
Superior Magnetic Aging Resistance: Maintains performance over long-term use
Good Workability: Suitable for automated high-speed punching and forming
MOOPEC’s Customization and Service Capabilities
Beyond supplying Baosteel CRGO grades, MOOPEC provides a one-stop solution, including:
Small batch & multi-spec supply – ideal for new project development
Fast prototyping and tooling – samples ready within 72 hours
Precision cutting and traceable quality control – from samples to trial production
Global delivery with multi-currency transactions – servicing Southeast Asia, Europe, and the Americas
Nominal Thickness(mm) | MOOPEC | Theoretical density (KG/dm³) | Min. Induction(T) | Min.Lamination factor(%) |
| 0.20 | M20G65 | 7.65 | 1.89 | 95.0 |
| 0.20 | M20G70 | 7.65 | 1.89 | 95.0 |
| 0.20 | M20G75 | 7.65 | 1.90 | 95.0 |
| 0.20 | M20G80 | 7.65 | 1.90 | 95.0 |
| 0.23 | M23G75 | 7.65 | 1.89 | 95.5 |
| 0.23 | M23G80 | 7.65 | 1.88 | 95.5 |
| 0.23 | M23G85 | 7.65 | 1.86 | 95.5 |
| 0.23 | M23G90 | 7.65 | 1.90 | 95.5 |
| 0.23 | M23G95 | 7.65 | 1.89 | 95.5 |
| 0.23 | M23G100 | 7.65 | 1.89 | 95.5 |
| 0.27 | M27G90 | 7.65 | 1.90 | 96.0 |
| 0.27 | M27G95 | 7.65 | 1.90 | 96.0 |
| 0.27 | M27G100 | 7.65 | 1.90 | 96.0 |
| 0.27 | M27G105 | 7.65 | 1.89 | 96.0 |
| 0.27 | M27G110 | 7.65 | 1.89 | 96.0 |
| 0.27 | M27G115 | 7.65 | 1.89 | 96.0 |
| 0.27 | M27G120 | 7.65 | 1.88 | 96.0 |
| 0.30 | M30G100 | 7.65 | 1.90 | 96.5 |
| 0.30 | M30G105 | 7.65 | 1.90 | 96.5 |
| 0.30 | M30G110 | 7.65 | 1.89 | 96.5 |
| 0.30 | M30G120 | 7.65 | 1.89 | 96.5 |
Future Trends: Thinner, Greener, More Efficient
Driven by global carbon neutrality goals and green energy growth, energy-efficient, high-induction CRGO materials—like Baosteel’s Hi-B® series—are becoming the industry standard.
Over the next decade, the market will prioritize:
Ultra-thin gauges
Low-loss performance
Eco-friendly manufacturing
Consistent magnetic properties
MOOPEC will continue to empower clients with advanced material solutions that balance cost, efficiency, and sustainability, supporting their competitive edge in the evolving energy equipment sector.
