The core requirements for aluminum strip in transformer winding are high conductivity, low loss, ease of winding, and long lifespan. The alloy grade directly determines purity, conductivity, and applicable scenarios. The alloy grades for aluminum transformer strip are 1050, 1060, 1070, and 1350. This article uses data to clarify the differences in purity and conductivity, and provides the most suitable grade for transformers.
The electrical conductivity of thin aluminum strips is determined by its purity and the presence of impurities such as iron and silicon: higher purity and fewer impurities result in lower resistivity, higher conductivity, lower transformer no-load/load losses, and more controllable temperature rise.
The industry-standard “% IACS” (International Annealed Copper Standard) measures conductivity; the annealed state (O state) is a commonly used soft state for winding, offering more stable conductivity.
Alloy grade | Minimum Aluminum Purity | Typical Conductivity(O temper) | Core Positioning |
1050 | ≥99.50% | ≥60.0%IACS | Economical General-Purpose Pure Aluminum |
1060 | ≥99.60% | ≥61.5%IACS | Balanced Cost-Effectiveness |
1070 | ≥99.70% | ≥62.7%IACS | Ultra-High Purity, High Conductivity |
1350 | ≥99.50% | ≥62.0%IACS | Electrical Engineering Standard Aluminum |
1050 aluminum alloy is made of basic industrial pure aluminum, offering the lowest cost. Its conductivity meets the minimum requirements for conventional low-voltage, small-capacity transformers. Impurity control is relatively lenient, making it suitable for general power distribution scenarios where losses are not a major concern and budgets are limited. It is not recommended for high-efficiency/high-capacity winding.
1060 aluminum strip has better purity and conductivity than 1050. It has good toughness and is less prone to cracking during winding, making it the most mainstream choice for general-purpose transformers worldwide. It balances conductivity, processing, and cost, and can be used for both oil-immersed and dry-type conventional winding, offering excellent value.
Of the four alloy grades, 1070 aluminum has the highest purity, best conductivity, minimal impurities, and lowest resistivity. It's suitable for high-efficiency energy-saving transformers, new energy transformers, and high-precision power supply transformers, making it the top choice for those seeking extremely low losses, though its cost is slightly higher.
1350 aluminum alloy is a dedicated electrical-grade aluminum (ASTM B230/IEC standard). While its purity is comparable to 1050, its iron and silicon impurities are strictly controlled, resulting in more stable conductivity, better creep resistance, and superior weldability. It's the designated grade for IEC standard equipment, with performance consistency superior to ordinary 1xxx pure aluminum.
For general applications: 1060. It balances conductivity, processing, and cost, covering the vast majority of oil-immersed/dry-type distribution transformers, making it the industry's "golden universal model."
For high efficiency/high precision: 1070. It is of top-tier purity and conductivity, lowest losses, suitable for energy-saving, new energy, and high-end power transformers.
For strict stable performance: 1350. It is electrical-grade aluminum and has stable performance, meeting IEC/IEEE requirements, essential for foreign trade projects.
For low-cost, low-configuration applications: 1050. It is only suitable for small-capacity, low-requirement, and budget-sensitive general equipment.
As an aluminum strip supplier, Haomei Aluminum has all these alloy grade. We recommend O temper aluminum strip for excellent ductility, resulting in crack-free winding and tight bonding.
Prioritize finely edged, burr-free aluminum strips to avoid puncturing insulation and causing partial discharge.
For larger capacity, higher voltage, and stricter efficiency requirements, choose 1070/1350 aluminum strip.