Why Amorphous Steel Cores Are Becoming the New Standard in 2026
Amorphous alloy cores are now the default choice in distribution transformers, not the alternative. This article covers the material economics, State Grid's 2026 procurement mandate, the standards that landed this year, and what changed in the supply chain. Comparison data and references at the end.
The Material Logic: No-Load Loss Is Where Amorphous Wins
The difference between amorphous alloy and grain-oriented silicon steel (CRGO) comes down to atomic structure. CRGO has an ordered crystal lattice. Amorphous alloy gets its structure from ultra-rapid solidification, which leaves the atoms disordered. No grain boundaries, no pinning sites. Coercivity drops, and the hysteresis loop area shrinks well below anything silicon steel can manage.
At 50 Hz, amorphous alloy's unit iron loss is ≤0.11 W/kg (P1.3T/50Hz). CRGO is ≤0.8 W/kg (P1.4T/50Hz). That's about a 7x gap. In distribution transformers, it shows up as 70%–80% lower no-load loss. Push to 600 Hz and 0.5 T, and amorphous core loss falls to roughly 10% of silicon steel's - a 90% reduction.
Here's why that matters more now than it did ten years ago. Distribution transformers on renewable-heavy grids sit at low load rates for long stretches. No-load loss is there the moment the unit is energized, load or no load. The lower the load rate, the bigger its slice of total loss. That's the operating window where amorphous pulls furthest ahead.
The trade-offs are real. Amorphous saturation flux density is 1.56 T, CRGO is 2.03 T. Magnetostriction coefficient is 26×10⁻⁶ against 2×10⁻⁶ - thirteen times worse, which is why these cores run louder. The material is also stress-sensitive, so clamping and annealing control have to be tighter. By 2026, these are manageable engineering problems. They don't kill the case for amorphous.
The 2026 Rule Change: From Encouragement to Hard Mandate
State Grid's 2026 work conference set a procurement target: amorphous alloy products must make up no less than 30% of distribution transformer purchases, and that target goes into the hard constraint assessment system. This time it's a hard target, not a suggestion.
The 2025 baseline was roughly 117,000 amorphous transformer units tendered, or 28% of distribution transformer procurement. Going from 28% to a hard 30% floor doesn't look like much on paper. But the rule's nature matters more than the number. A hard constraint sets a trajectory, and it doesn't get revised downward.
Standards landed in parallel. T/CIEP 0216-2026, covering energy efficiency optimization for amorphous alloy transformers, was released February 6, 2026 and took effect February 13. National standards GB/T 25446-2026 (oil-immersed) and GB/T 22072-2026 (dry-type) came out September 28, 2026, set to take effect April 1, 2027. Both replace older versions from 2010 and 2018, and both widen their scope - "distribution transformer" becomes "power transformer," with new performance parameters for renewable energy applications.
Design institutes and manufacturers now have a compliance target instead of a reference document.
Supply Chain: The Bottleneck Has Eased
Amorphous ribbon dominates core cost. For years, stable supply sat with a handful of producers, and that capped adoption more effectively than any technical limitation. By 2026, upstream ribbon capacity has caught up with midstream core manufacturing. Delivery cycles and cost volatility have narrowed a lot compared to five years ago.
The market structure reflects that maturity. Hitachi, ABB, and Siemens lead the global amorphous core transformer market, with the top three holding over 20% combined share. Asia-Pacific accounts for more than 45% of the global market. Oil-immersed units make up roughly 85% of the product mix, with utilities as the dominant buyer.
Procurement data confirms the shift from pilot projects to routine purchasing. Through 2026, amorphous core and component procurement announcements appeared densely across the chain, from research institutes to local grid companies.
Comparison Data
| Metric | Amorphous Alloy Core | CRGO Silicon Steel Core | Data Conditions |
| Unit iron loss | ≤0.11 W/kg (P1.3T/50Hz) | ≤0.8 W/kg (P1.4T/50Hz) | Material datasheet |
| Saturation flux density (Bs) | 1.56 T | 2.03 T | Intrinsic property |
| Magnetostriction (λs) | 26×10⁻⁶ | 2×10⁻⁶ | Intrinsic property |
| Permeability (μ) | 15,000+ | 5,000–8,000 | Comparative range |
| No-load loss reduction | 70%–80% lower | Baseline | Distribution transformer |
| State Grid 2026 procurement floor | ≥30% | No hard requirement | Hard constraint |
Amorphous advantages sit in no-load loss and high-frequency operation. Its weaknesses - saturation density and noise - are engineering problems, not performance disqualifiers. Once procurement rules set a hard floor, tolerance for material trade-offs rises, and the advantage side gets weighted more heavily.
Figure 1. Core loss comparison at 50 Hz - amorphous alloy vs CRGO silicon steel.
The Bottom Line
Amorphous cores became the "new standard" in 2026 because of loss economics, not because they outperform silicon steel across the board. With carbon constraints and grid loss assessments getting tighter, every watt of no-load loss carries a measurable cost. Amorphous alloy's structural edge in no-load loss lines up with how a distributed, renewable-heavy grid actually operates.
It won't replace silicon steel everywhere. High-capacity, high-load-rate, noise-sensitive applications stay with CRGO. Amorphous is the default on the distribution side. Silicon steel remains the workhorse on the power side.
Winding Selection: Copper or Aluminum?
Core material is only half the spec. Winding conductor choice follows a different logic, and the answer depends on the project.
High fault currents? Go copper. Lower resistivity, better thermal conductivity, and it holds up under short-circuit stress and sustained overload. If the transformer sits close to generation, serves heavy industrial loads, or connects to a grid with high available fault current, copper is the defensible call.
Cost-sensitive distribution job with space to spare? Aluminum works fine. Lighter, cheaper, and perfectly adequate for standard distribution duty cycles where fault current levels are moderate and the physical envelope isn't the binding constraint. Space matters here - aluminum needs a larger conductor cross-section for equivalent current capacity, which means a bigger core and tank.
Not sure which one fits? Send us your specs - voltage class, fault current level, load profile, space constraints, budget. We'll give you a straight answer, and the reasoning behind it.
About TIG - Trust in Grid
TIG (Trust in Grid) is a global transformer manufacturer and supplier, serving utilities, OEMs, EPC contractors, and industrial clients worldwide. Our core business is transformer manufacturing - oil-immersed and dry-type distribution transformers, power transformers, and custom units built to project specifications. Alongside complete transformers, we supply transformer components and materials, including amorphous alloy cores, CRGO silicon steel cores, and wound core assemblies.
What we bring to your project:
• Complete transformer manufacturing - oil-immersed, dry-type, and custom configurations
• Amorphous and silicon steel capability - dual material lines aligned with the 2026 State Grid mandate and the new GB/T 25446-2026 / GB/T 22072-2026 standards
• Components and materials - amorphous cores, CRGO cores, and wound core assemblies with full material traceability
• Global delivery - we ship and support projects across Asia, Europe, the Middle East, Africa, and the Americas
We work with customers who need direct answers on transformer selection, core material choice, winding conductor decisions, and compliance with evolving grid standards. Whether you're specifying a complete transformer or sourcing cores and components, we quote to your specs, not our inventory.
TIG - Trust in Grid
www.trustingrid.com
asia@trustingrid.com
References
•1. S.K. Singh et al., "Amorphous Core Distribution Transformer with Improved Efficiency and Low Loss for Power Sector Application," European Journal of Applied Science and Technology, vol. 2(3), pp. 160–166, May–Jun 2024.
•2. China Quality Certification Centre, "Energy-Saving Comparison Data Table: Amorphous Alloy Oil-Immersed Transformers vs. Silicon Steel Oil-Immersed Transformers."
•3. "State Grid Sets 2026 Amorphous Distribution Transformer Share at ≥30%," February 2026.
•4.T/CIEP 0216-2026, Technical Requirements for Energy Efficiency Optimization of Amorphous Alloy Transformers, China Industrial Environmental Protection Promotion Association, released February 6, 2026.
•5. GB/T 25446-2026, Technical Parameters and Requirements for Oil-Immersed Amorphous Alloy Core Power Transformers, National Transformer Standardization Technical Committee, released September 28, 2026.
•6. GB/T 22072-2026, Technical Parameters and Requirements for Dry-Type Amorphous Alloy Core Power Transformers, National Transformer Standardization Technical Committee, released September 28, 2026.
•7. QYResearch, "2026 Global Amorphous Core Transformer Market Share and Ranking."
•8. "Research on Magnetic Field Characteristics of Amorphous Alloy and Grain-Oriented Silicon Steel Hybrid Magnetic Circuit Iron Core," IET Electric Power Applications, DOI: 10.1049/ema3.12014.
•9. China Science Communication, "Amorphous Alloy Transformers," November 2018.
•10. "Summary of Key Points from State Grid's 2026 Work Conference," East Money Information, March 2026.