0.23mm ≤0.85 W/kg Grain Oriented Electrical Steel
Sep 16, 2026
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0.23mm ≤0.85 W/kg grain oriented electrical steel is the premium benchmark specification for high-efficiency transformer core materials.
This guide systematically covers its technical parameters, EN 10107 grade designation system, generational differences between CRGO steel and Hi-B electrical steel, domain refined electrical steel as the technology ceiling, non grain oriented electrical steel / CRNGO steel route comparison, silicon steel lamination processing chain, transformer core steel application scenarios, electrical steel coil delivery specifications, and electrical steel price pricing logic - along with a complete electrical steel specification parameter checklist and an online inquiry channel.
What Is 0.23mm ≤0.85 W/kg Grain Oriented Electrical Steel?
0.23mm ≤0.85 W/kg grain oriented electrical steel is the premium specification designation for grain oriented electrical steel (GOES). It precisely defines three core dimensions: nominal thickness 0.23 mm (the thinnest mainstream production gauge for GOES), maximum specific total loss ≤0.85 W/kg (at 1.7T magnetic polarization and 50Hz frequency), and material type: grain oriented (electrical steel with grains highly oriented along the rolling direction).
This specification corresponds to grade M085-23S in the EN 10107 grade system, 23QG085 in JIS C 2553, and 23G085 in ASTM A672. All three standards refer to the same product specification - only the naming conventions differ.
Grade Designation Breakdown: M085-23S
- M - Magnetic, magnetic material identifier
- 085 - Maximum core loss 0.85 W/kg × 100 = 085
- 23 - Nominal thickness 0.23mm × 100 = 23
- S - Strip and sheet, grain-oriented (GO suffix)
The core loss indicator of 0.85 W/kg @1.7T/50Hz and magnetic polarization of ≥1.85T @800A/m are the key thresholds that classify this material as Hi-B electrical steel (high permeability grain oriented electrical steel). Conventional CRGO steel under the same conditions typically has a core loss of 1.00–1.20 W/kg and magnetic polarization of about 1.78T. Therefore, the 0.23mm ≤0.85 W/kg specification definitively belongs to the Hi-B grade, not the conventional CGO grade.
From an application perspective, this specification is primarily used in extra-high-voltage power transformers (220kV+), nuclear power main transformers, and large hydro-generator transformers where no-load loss requirements are stringent - making it the premium choice for transformer core steel.
CRGO Steel vs Hi-B Electrical Steel: Magnetic Property Comparison
CRGO steel (Cold Rolled Grain Oriented steel) is the general term for grain oriented electrical steel, encompassing two technology generations: Conventional Grain Oriented (CGO) and High Permeability (Hi-B). Hi-B electrical steel is the high-performance upgrade of CRGO steel, pioneered by Nippon Steel in the 1960s. The core difference between the two lies in the cold rolling process route and the resulting grain orientation degree.
| Parameter | CRGO Steel (CGO) | Hi-B Electrical Steel |
|---|---|---|
| Cold Rolling Process | Two-stage cold rolling (intermediate annealing) | Single-stage large-reduction cold rolling |
| B800 (T @800A/m) | 1.78–1.82 | ≥1.85 |
| Core Loss P1.7/50 (W/kg) | 1.00–1.40 | 0.85–1.10 |
| Typical Thickness | 0.30 / 0.35 mm | 0.23 / 0.27 / 0.30 mm |
| Grain Size | 3–5 mm | 5–10 mm |
| Orientation Degree (Goss fraction) | ~85% | ~95% |
| Typical Application | Conventional distribution transformers | Large power transformers, high-efficiency transformers |
| This Article's Core Spec | - | 0.23mm ≤0.85 W/kg ✓ |
The core principle behind Hi-B electrical steel's lower core loss: single-stage large-reduction cold rolling produces a stronger cold-rolling texture, and after secondary recrystallization annealing, the Goss-oriented grain fraction increases to approximately 95% (vs. ~85% for CGO), reducing domain wall motion resistance and lowering hysteresis loss.However, Hi-B's larger grains also mean wider magnetic domains, which can increase anomalous eddy current loss at high frequencies - this is precisely the motivation behind the subsequent domain refined electrical steel technology.
Does Your Transformer Need Hi-B or CGO Grade?
Different transformer efficiency classes require different GOES specifications. Using a lower grade can result in no-load loss exceeding standards and energy efficiency non-compliance. We can provide free grade recommendations based on your transformer design parameters (capacity, voltage class, efficiency standard) - avoiding both over-specification waste and under-specification compliance issues.
Domain Refined Electrical Steel: The Technology Ceiling for 0.23mm GOES
Domain refined electrical steel, also known as laser-scribed electrical steel, is the ultimate low-loss product built on Hi-B electrical steel by further refining magnetic domains through laser or mechanical scribing. It represents the highest level of GOES manufacturing technology.
Technical Principle
GOES core loss = hysteresis loss + eddy current loss. Hi-B electrical steel reduces hysteresis loss through high orientation degree, but its large grains lead to wide magnetic domains (up to several millimeters), and domain wall motion during alternating magnetization generates high anomalous eddy current loss.
Domain refined electrical steel uses laser irradiation at regular intervals along the transverse direction on the steel surface, introducing localized stress fields that "fracture" large domains into narrower sub-domains, reducing domain wall motion amplitude and lowering anomalous eddy current loss by 5–15%.
| Thickness | Hi-B Core Loss (W/kg) | DR Grade Core Loss (W/kg) | Improvement |
|---|---|---|---|
| 0.23mm | 0.85–0.90 | ≤0.78 | ↓ 8–12% |
| 0.27mm | 0.90–1.00 | ≤0.85 | ↓ 6–10% |
| 0.30mm | 1.00–1.10 | ≤0.95 | ↓ 5–8% |
Specification Positioning Note
In the GOES technology ladder: CRGO steel → Hi-B electrical steel → domain refined electrical steel.
The core spec in this article, 0.23mm ≤0.85 W/kg, sits at the high end of Hi-B grade, just one step away from the DR grade's ≤0.78 W/kg. If your transformer design requires core loss ≤0.78 W/kg, confirm that the supplier has DR production line capability.
Electrical Steel Specification: Complete Technical Parameter Checklist for 0.23mm ≤0.85 W/kg GOES
A complete electrical steel specification (technical specification sheet) goes far beyond just thickness and core loss figures. Below is the complete parameter checklist based on an actual overseas customer inquiry, covering magnetic properties, dimensions, coating, test methods, welding restrictions, and logistics requirements.
0.23mm ≤0.85 W/kg Grain Oriented Electrical Steel - Complete Electrical Steel Specification
| Parameter | Specification | Test Standard | Engineering Significance |
|---|---|---|---|
| Material Type | Grain oriented electrical steel | - | GOES |
| Nominal Thickness | 0.23 mm | Micrometer multi-point measurement | Determines eddy current loss level |
| Max Specific Total Loss | ≤0.85 W/kg @1.7T, 50Hz | IEC 60404-3 (SST) | Core efficiency indicator |
| Min Magnetic Polarization | ≥1.85 T @800A/m, 50Hz | IEC 60404-3 | Hi-B grade determination |
| Min Stacking Factor | ≥0.945 | IEC 60404-13 | Effective material ratio in core |
| Standard Reference | EN 10107 | - | Product standard system |
| Coating Resistance | >15 Ω·cm² | IEC 60404-11 | Interlaminar insulation |
| Welding Restriction | No welding points allowed | - | Magnetic circuit continuity |
| Coil Weight | 3–5 MT/coil | - | Logistics & processing management |
| Coil Width | 960–1150 mm (preferred 1000/1150mm) | - | Match core dimensions |
| Packing | Seaworthy packing | - | Marine moisture & salt spray protection |
| Shipping | Containers mandatory | - | Logistics safety & control |
Need MTC Sample Documents?
The Mill Test Certificate (MTC) is the core document for verifying material compliance. We can provide a typical MTC sample for 0.23mm ≤0.85 W/kg grain oriented electrical steel, including complete chemical composition, magnetic property test data (SST method), and coating resistance inspection reports - for your technical team's pre-qualification evaluation.
Silicon Steel Lamination: Processing Chain from Coil to Transformer Core for 0.23mm GOES
Silicon steel lamination is the key processing stage from electrical steel coil to finished transformer core. After GOES is delivered in coil form, it must go through the following processes to be assembled into a core:
Silicon Steel Lamination Processing Flow
- Slitting: Cutting wide electrical steel coils longitudinally into narrow coils of target widths. GOES must be used along the rolling direction - slitting maintains directional consistency.
- Shearing / Stamping: Cutting narrow coils into specific-shaped laminations (stepped / L-shaped / V-shaped) for step-lap core designs.
- Deburring: Stamping edge burrs disrupt interlaminar insulation and increase eddy current loss - must be removed by grinding or roller pressing.
- Stress Relief Annealing: Mechanical stress from stamping damages magnetic properties; high-requirement applications need 800°C stress relief annealing.
- Stacking: Laminations are stacked and assembled into the core, secured with fixtures and fasteners.
Four Key Material Requirements for Lamination
- Thickness Tolerance ≤±0.005mm: Excessive tolerance affects the stacking factor - 0.23mm spec requires ≥0.945.
- Flat Strip Shape: Waviness and curl affect automatic lamination line operation - Hi-B grade has higher shape requirements.
- Coating Processability: C2 inorganic coating withstands high-temperature annealing but is brittle; C3 semi-organic coating is tougher but not high-temperature resistant. Choose coating type based on whether annealing is needed.
- No Welding Joints: Automatic lamination lines have zero tolerance for welding joints - welds can jam dies or cause lamination misalignment. This is the fundamental reason behind "No welding points allowed" in the electrical steel specification.
The stacking factor is a comprehensive indicator of silicon steel lamination quality. The 0.23mm ≤0.85 W/kg spec requires ≥0.945, meaning effective silicon steel material accounts for no less than 94.5% of the core. Thickness tolerance, coating thickness, and strip flatness collectively determine this value.
| Specification | Core Loss Level | Typical Application | Efficiency Class |
|---|---|---|---|
| 0.35mm CGO | 1.20 W/kg | Conventional distribution transformers | Standard efficiency |
| 0.30mm Hi-B | 1.00 W/kg | Large power transformers | EU Tier 2 |
| 0.27mm Hi-B | 0.90 W/kg | Large power transformers | High efficiency |
| 0.23mm Hi-B | 0.85 W/kg | EHV transformers, nuclear power | Ultra-high efficiency |
| 0.23mm DR | ≤0.78 W/kg | Maximum efficiency transformers | Highest efficiency |
| Parameter | Typical Value | Description |
|---|---|---|
| Coil Weight | 3–5 MT/coil | Facilitates lifting and single-coil management |
| Coil Width | 960–1150 mm | Matches transformer core dimensions |
| Preferred Widths | 1000mm / 1150mm | Corresponds to standard core limb widths |
| Inner Diameter | 508mm (20 inch) | Industry standard ID |
| Outer Diameter | 1200–1500mm | Depends on coil weight and width |
| Sleeve | Individual inner sleeves | Prevents coil collapse, facilitates lifting |
Need Custom Slitting for Non-Standard Widths?
Standard widths (960–1150mm) can be delivered quickly. For non-standard widths (e.g., 850mm, 914mm, etc.), we offer custom slitting services. Please specify your target width, coil weight, and quantity in the inquiry - we will evaluate slitting feasibility and delivery time.
FAQ
What is the difference between domain refined electrical steel and Hi-B?
Domain refined electrical steel is a higher-end product built on Hi-B by further refining magnetic domains through laser or mechanical scribing. DR grade has lower core loss (at 0.23mm: ≤0.78 W/kg vs. Hi-B's 0.85 W/kg), but fewer global production facilities and higher prices. DR grade is primarily used in nuclear power and EHV transformers requiring extreme low loss.
Can non grain oriented electrical steel (CRNGO steel) substitute GOES in transformers?
Not recommended. Transformer cores have fixed flux direction, and GOES has optimal magnetic properties in the rolling direction - a perfect match. Non grain oriented steel, while uniform in all directions, is inferior to GOES's rolling direction in any given direction - using it in transformers would result in higher core loss and reduced efficiency. The two material types have different purposes and are not interchangeable.
How do you convert core loss data between 50Hz and 60Hz?
Core loss at 60Hz is typically 1.15–1.25 times that at 50Hz, depending on thickness and magnetic induction. Thinner gauges (0.23mm) have lower frequency sensitivity than thicker gauges (0.35mm). In formal procurement, MTC data at the customer's required frequency should be used as the standard - direct conversion is not acceptable.
What are the main factors affecting electrical steel price?
Core factors ranked by importance: thickness gauge (thinner = more expensive), core loss grade (DR > Hi-B > CGO), no-welding requirement (price premium), order quantity (small = premium), coil width (non-standard = premium), coating type, seaworthy packaging cost, silicon alloy raw material market linkage, and exchange rate fluctuations. The 0.23mm ≤0.85 W/kg spec is priced at approximately 2.2–2.5 times that of conventional 0.35mm CGO.