What is Aluminum Foil for Transformer Windings?
Aluminum transformer strip (also known as "aluminum strip for transformer windings") is a thin, flat aluminum product. It is a key raw material specifically designed for manufacturing transformer windings, especially for dry-type transformers.
It is mainly processed from high-purity
aluminum (such as grades 1050, 1060, 1070, and 1350) and is usually in O temper
(soft temper) to ensure excellent processability.
Aluminum foil for transformer windings is mainly used in dry-type transformers.
Core Advantages of Using Aluminum Strip for Transformers
Why do 70% of medium and low-voltage transformer manufacturers choose aluminum strips over copper strips? Here are the key advantages:
- Superior Cost-Effectiveness: The cost of aluminum is 30%-50% lower than that of copper.
- Excellent Electrical Conductivity: Pure aluminum (e.g., grade 1060) has an electrical conductivity of up to 61% International Annealed Copper Standard (IACS).
- Lightweight Design: Aluminum has a density of 2.7 g/cm³ (only 1/3 that of copper), which can reduce the weight of transformers by 25%-30%.
- Strong Corrosion Resistance: Aluminum forms a dense oxide film (Al₂O₃) in the air, which can resist moisture, dust, and industrial pollutants.
- Outstanding Processability: Aluminum strips for transformers are usually supplied in soft temper (O temper), which can be easily bent, stamped, and wound without cracking or deformation.
Worthwill’s Aluminum Strip Specifications for Transformers
Basic Information
- Product Name: Aluminum Foil for Transformer Windings
- Alloy: 1050, 1060, 1070, 1350
- Temper: O
- Thickness: 0.1mm - 3.5mm
- Width: 10mm - 1600mm
- Edges: Rounded Edges / Straight Edges
- Inner Diameter of Paper Core: 76mm, 150mm, Ø300mm, Ø400mm (the diameter of the paper core is related to the thickness of the foil strip)
- Samples: Available
- HS Code: 76069100.00
Tolerance Range
Thickness Tolerance
| Thickness Range (mm) | Thickness Tolerance (mm) |
| 0.08 - 0.20 | ±8% of nominal thickness |
| >0.20 - 0.40 | ±0.02 |
| >0.40 - 0.80 | ±0.03 |
| >0.80 - 1.10 | ±0.04 |
| >1.10 - 1.40 | ±0.05 |
| >1.40 - 2.00 | ±0.06 |
| >2.00 - 2.50 | ±0.07 |
| >2.50 - 3.00 | ±0.08 |
Width Tolerance
| Thickness Range (mm) | Width Tolerance (+) | ||||
| <=100.0 | >100.0-300.0 | >300.0-500.0 | >500.0-1250.0 | >1250.0-1500.0 | |
| >0.08 - 0.20 | 0.3 | 0.4 | 0.6 | 1.0 | 2.0 |
| >0.20 - 0.60 | 0.3 | 0.4 | 0.6 | 1.5 | 2.5 |
| >0.60 - 1.00 | 0.3 | 0.5 | 1.0 | 1.5 | 2.5 |
| >1.00 - 2.00 | 0.4 | 0.7 | 1.2 | 2.0 | 2.5 |
| >2.00 - 3.00 | 1.0 | 1.0 | 1.5 | 2.0 | 2.5 |
Lateral Curvature Tolerance
| Width (mm) | Lateral Curvature (measured over a strip length of 2000/1000mm) | |
| Over | Up to and including | |
| 15 | 100 | 6mm / 1.5mm |
| 100 | 300 | 4mm / 1.5mm |
| 300 | 600 | 3mm / 0.7mm |
| 600 | 1540 | 2mm / 0.5mm |
Edge Treatment
Worthwill supports Rounded Edges and Straight Edges. The radius of rounded edges can be customized, and the edges are smooth and burr-free, including the following types:
- Rounded Edges
- Straight Edges with Radius
- Straight Edges with Chamfer
- Straight Edges with 90° Angles
Edges (Burr, Camber, Delamination)
| Thickness | Burr | Camber | Layering |
| <=0.20 | <=0.03 | <=0.5 | <=4 |
| >0.20 | <=0.05 | <=2 | <=5 |
Hot-Selling Aluminum Strip and foil for Transformer Windings
1050 Aluminum Strip for Transformer Windings
- Alloy: 1050 O
- Aluminum Content: ≥99.5%
- Electrical Conductivity: ≥60% IACS
1060 Aluminum Strip for Transformer Windings
- Alloy: 1060 O
- Aluminum Content: ≥99.6%
- Electrical Conductivity: ≥61.5% IACS
1070 Aluminum Strip for Transformer Windings
- Alloy: 1070 O
- Aluminum Content: ≥99.7%
- Electrical Conductivity: ≥62.7% IACS
1350 Aluminum Strip for Transformer Windings
- Alloy: 1350 O
- Aluminum Content: ≥99.5%
- Electrical Conductivity: ≥62% IACS
Chemical Composition and Physical Properties
Chemical Composition
| Elements | Content (max%) | |||
| 1050 | 1060 | 1070 | 1350 | |
| Silicon (Si) | 0.25 | 0.25 | 0.2 | 0.1 |
| Iron (Fe) | 0.40 | 0.35 | 0.25 | 0.4 |
| Magnesium (Mg) | 0.05 | 0.03 | 0.03 | - |
| Zinc (Zn) | 0.05 | 0.05 | 0.04 | 0.05 |
| Manganese (Mn) | 0.05 | 0.03 | 0.03 | 0.01 |
| Titanium (Ti) | 0.03 | 0.03 | 0.03 | 0.01 |
| Copper (Cu) | 0.05 | 0.05 | 0.04 | 0.05 |
| Vanadium (V) | 0.05 | 0.05 | - | 0.01 |
| Chromium (Cr) | - | - | - | 0.01 |
| Boron (B) | - | - | 0.05 | - |
| Aluminum (Al) | ≥99.5 | ≥99.6 | ≥99.7 | ≥99.5 |
Physical Properties
| Property Index | 1050 O | 1060 O | 1070 O | 1350 O |
| Electrical Conductivity (20℃) | ≥60% IACS | ≥61% IACS | ≥62% IACS | ≥61% IACS |
| Electrical Resistivity (20℃) | ≈2.9×10⁻⁸ | ≈2.86×10⁻⁸ | ≈2.82×10⁻⁸ | ≈2.85×10⁻⁸ |
| Thermal Conductivity (20℃) | ≈220 | ≈229 | ≈235 | ≈228 |
| Linear Thermal Expansion Coefficient (20-100℃) | ≈23.8 | ≈23.6 | ≈23.5 | ≈23.7 |
| Elastic Modulus (20℃) | ≈70 | ≈70 | ≈70 | ≈70 |
| Tensile Strength (Rm) | 70-95 | 75-100 | 70-90 | 75-95 |
| Yield Strength (Rp0.2) | ≥30 | ≥35 | ≥28 | ≥32 |
| Elongation (L=50mm) | 20%-28% | 22%-29% | 25%-30% | 22%-28% |
| Brinell Hardness (HB) | 15-18 | 16-19 | 15-18 | 16-18 |
Data sources:
- https://www.makeitfrom.com/material-properties/1060-O-Aluminum
- https://www.makeitfrom.com/material-properties/1050-O-Aluminum
- https://www.makeitfrom.com/material-properties/1070-O-Aluminum
- https://www.makeitfrom.com/material-properties/1350-O-Aluminum
Packaging and Transportation
We adopt standard sea freight packaging. Foam film is used to protect the edges and surface of the aluminum strip and foil for transformer windings from damage; the aluminum strip and foil is wrapped in plastic film, with desiccant placed inside. The outer packaging uses wooden pallets and wooden cases.
Why Choose Us?
Worthwill is a professional manufacturer of aluminum strip and foil for transformer windings. The production process of our winding aluminum strip meets strict electrical, mechanical, and surface quality standards to ensure stable operation of transformers under different loads and environments.
Our products have the following characteristics:
- Good formability and uniform thickness
- Burr-free edges for safe use
- Excellent electrical and thermal conductivity
- Good corrosion resistance and weldability
- Uniform and smooth surface, clean and oil-free
- Light weight and low price
Each purchase order is accompanied by a material certificate that meets customer requirements. The material certificate must include at least the following tests:
- Chemical composition (to confirm aluminum purity)
- Electrical conductivity test
- Mechanical properties (tensile and bending tests)
- Hardness measurement
