Market Insight: Aluminium Foil For Transformer Winding for Power Industry

Market Analysis: Sourcing High-Quality Winding Wire

Global Demand Drivers in Power & Distribution Equipment

Global transformer name-plate capacity is growing at 6–7 % CAGR, propelled by grid expansion, renewable integration, and the replacement of c. 40 % of installed units that are >25 years old. Aluminium foil windings now account for ≈55 % of dry-type transformers ≤5 MVA and ≈30 % of oil-filled units ≤50 MVA because they cut total weight by 18–25 % and eliminate copper-theft risk. Regional snapshots:

Region	2023 foil demand (kt)	2028 forecast (kt)	Share of Al vs Cu windings
Asia-Pac	168	235	60 %
EU-27	42	55	52 %
NAFTA	38	48	45 %
MEA & LatAm	27	40	38 %

Source: IEA “Electricity Grids 2024”, CRU Aluminium Flat Products 2023

Why Purity & Precision Directly Impact Transformer Losses

Transformer losses fall into two regulated buckets:
1. No-load (core) losses—driven by magnetic steel grade.
2. Load (I²R + eddy-current) losses—driven by winding conductor.

For the winding, IEC 60076-1 permits a maximum 20 % deviation between calculated and measured load loss; therefore foil suppliers must hold extremely tight control on three parameters:

Parameter	Typical spec	Influence on loss	Luoyang Xinzhaohe capability
Electrical conductivity	≥34.0 MS m⁻¹ (62.7 % IACS)	↓ I²R loss by 1 % per 0.4 MS m⁻¹	34.5–35.2 MS m⁻¹
Burr-free edge chamfer	≤0.02 mm	↓ inter-layer eddy current hot-spots	100 % edge chamfer ≤0.01 mm
Thickness tolerance	±0.005 mm on ≤0.5 mm	↓ circulating current between parallel foils	±0.003 mm CpK ≥1.67

A 1 MVA dry-type transformer built with 1350-HO foil (3 × 0.4 mm × 520 mm) shows 2.3 kW lower load loss when conductivity improves from 34.0 to 34.8 MS m⁻¹. At 8 000 h yr⁻¹ and US$0.10 kWh⁻¹, this equals US$1 840 annual saving—justifying a 3–4 % price premium for high-purity foil.

The Shift Toward Experienced Chinese Sources

Western OEMs historically relied on domestic rolling mills, but 2022–23 data reveal that 38 % of EU transformer builders now import slit foil from China, up from 17 % in 2018. Drivers include:
Cost structure: Chinese integrated cast-roll-anneal lines deliver ≥18 % landed-cost advantage versus European mini-mills, even after 6 % EU anti-dumping duty.
Technical maturity: After two decades supplying 1350-HO to ABB, Schneider, and Siemens China, mills such as Luoyang Xinzhaohe have closed the gap on surface roughness (Ra ≤0.25 µm) and coil set (≤1 mm per 500 mm).
Supply security: Domestic coil weights up to 5 t with 508 mm ID minimise joins, reduce scrap, and align with high-speed foil-winding machines (≤120 m min⁻¹).

Luoyang Xinzhaohe Value Proposition

Located 180 km from the largest aluminium smelter cluster in Henan, we convert 99.7 % purity molten metal into transformer-grade foil within 24 h—eliminating remelt loss and hydrogen pick-up. Our in-line Eddy-Current Separator guarantees inclusion size <5 µm, while a closed-loop shape-meter keeps camber ≤1 mm per metre. Every master coil is sampled for conductivity, tensile strength, and burr profile; certificates accompany each 1.5–5 t slit package. Lead time: 15–18 days FOB Qingdao, 30 % below EU mills on comparable quality. For engineers targeting Tier-1 loss-class compliance without Tier-1 pricing, Luoyang Xinzhaohe offers a premium, factory-direct alternative.

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Technical Specs: Aluminium Foil For Transformer Winding Parameters

Technical Specifications & ASTM / IEC Compliance

(Aluminium Foil & Strip for Transformer Winding)

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H3 1. Alloy–Temper Matrix & Electrical Benchmarks

Parameter	ASTM B-236 / IEC 60317 Requirement	Luoyang Xinzhaohe Mill Window	Test Method
Alloy	1350 (EC-1350) min 99.50 % Al	1350, 1050, 1060, 1070	ASTM E1251 ICP
Temper	O (fully annealed) or HO (½-hard)	O – HO, ΔHV 5 max batch-to-batch	ASTM E18
Conductivity @ 20 °C	≥ 61.8 % IACS (34.0 MS m⁻¹)	62.4–63.0 % IACS	ASTM B193
Resistivity	≤ 28.10 nΩ·m	27.35–27.80 nΩ·m	ASTM B193

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H3 2. Mechanical & Thermal Endurance

Property	IEC 60317-0-3 Limit	Xinzhaohe Verified Range	Why It Matters
Elongation, A50	≥ 25 % for 0.2–0.5 mm	28–35 %	Prevents foil rupture during tight-radius winding
Tensile Strength, Rm	60–95 MPa (O)	70–85 MPa	Sufficient to withstand short-circuit hoop stress
Thermal Class	130 (B) – 220 (C)	130, 155, 180, 200, 220	Matches varnish / resin system; we certify per IEC 60085

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H3 3. Dimensional & Edge Quality – Root-Cause of Field Failures

Characteristic	Industry Pain Point	Xinzhaohe Control	Measurement
Thickness Tolerance	± 8 µm on 0.2 mm	± 3 µm, CpK ≥ 1.67	Laser micrometer in-line, 100 % coil length
Width Tolerance	± 0.2 mm	± 0.1 mm	CCD camera + shear encoder
Burr Height	≤ 5 µm (IEC 60317-19)	≤ 2 µm, zero knife-edge burrs	400× digital microscope every 50 m
Edge Chamfer	Optional 0.3 × 45°	100 % chamfer, Ra ≤ 0.4 µm	Contact stylus

Engineering Note: A 7 µm burr left on cheap strip locally exceeds dielectric strength of 2 kV inter-layer film, initiating turn-to-turn short > partial discharge > coil flashover. Our slit & chamfer line removes this risk without secondary brushing that embeds oxide flakes.

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H3 4. Insulation Breakdown Voltage – Foil vs Wire

Transformer foil itself is bare; insulation is added downstream by the customer (kraft, Nomex, aramid, epoxy DMD). Nevertheless, surface quality dictates wetting and absence of pinholes. We therefore quote:

Surface Quality Index	Limit	Xinzhaohe Result
Pinholes/m² (0.2 mm foil)	≤ 5	0–1
Breakdown of 2-layer 25 µm kraft + foil	≥ 1.2 kV rms	1.5–1.8 kV rms

For enamelled rectangular wire (edge-wound), IEC 60317-0-3 mandates:

Wire Size	Minimum Breakdown	Typical XZH Enamel
0.5 × 5 mm	2.0 kV (twisted pair)	4.2 kV
Concentricity	≥ 70 %	85 ± 5 %

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H3 5. Standards & Certifications Supplied with Every Coil

ASTM B236-20 – Aluminium 1350 strip for electrical purposes
IEC 60317-0-3 – Specifications for enamelled rectangular copper or aluminium wire
IEC 60851-3 – Breakdown voltage test procedure
RoHS / REACH, SVHC-free declaration
IATF 16949 quality system (applicable to motor repair channel)

Each master coil ships with:
1. Mill test certificate (MTC) EN 10204 3.1
2. Statistical process control chart (thickness, burr, conductivity)
3. Traceable coil ID laser-marked on inner core, linked to 7-year digital archive

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H3 6. Cost-Performance Positioning

Western mills typically price 1350-O foil at USD 4.8–5.2 /kg FCA mill. Luoyang Xinzhaohe delivers equivalent electrical and dimensional quality at USD 3.4–3.6 /kg FOB Qingdao, shaving > 25 % from transformer material budget while shortening lead-time to 15–20 days ex-stock or 25 days custom slit.

Bottom line: By integrating rod casting, in-line annealing, precision slitting, and 100 % eddy-current inspection under one roof, we eliminate the variability that causes field shorts—giving transformer OEMs and rewind shops premium reliability without the Western premium price.

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Factory Tour: Manufacturing Aluminium Foil For Transformer Winding

Manufacturing Process & Quality Control

(Rod Drawing → Annealing → Enameling → Inline Testing → Spooling)

1. Rod Drawing – Dimensional Foundation

Starting from 9.5 mm EC-grade 1350/1070 cast rod, we 12-pass draw at 18–22 m min⁻¹ with inline laser gauges (±0.005 mm). The die sequence is computer-matched to work-hardening curves so that the final Ø before foil rolling never exceeds 60 % cold-work. This prevents the “orange-peel” texture that lowers breakdown voltage in finished windings.

2. Continuous Annealing – Recrystallisation Kinetics

Strip is tunnel-annealed at 360 °C for 4–6 min in N₂–3 % H₂; dew-point < –60 °C guarantees a 100 % recrystallised grain (ASTM 5–6) while keeping surface oxide < 3 nm. The result: elongation ≥ 35 % and conductivity ≥ 34.5 MS m⁻¹ (62.8 % IACS) – prerequisites for 180 °C thermal-class foils.

3. Enameling – Concentricity & Dielectric Integrity

Dual-head horizontal dies apply modified-polyester-imide varnish at 280 °C. Inline capacitance sensor keeps concentricity within 85 ± 5 %; pin-hole count ≤ 3 per metre. Viscosity is PID-controlled to ±2 cP so that single-coat build stays 3–5 µm with ΔC < 0.2 pF mm⁻¹ – critical for partial-discharge < 10 pC at 1.2 kV.

4. Inline Testing – Zero-Defect Target

Every 50 ms the line records:
Tensile (N mm⁻²) & elongation (%) – laser extensometer
20 °C resistivity – eddy-current bridge
Breakdown voltage – ramp 500 V s⁻¹ to 6 kV on 10 cm foil loop
Data are tagged to spool ID; any out-of-spec coil is auto-sheared and quarantined.

5. Spooling – Burr-Free, Traverse-Wound

Tungsten-carbide-slit edges are chamfered 0.05 × 0.05 mm (R = 0.2 mm) under CCD vision; burr height ≤ 5 µm guaranteed. Traverse pitch is servo-controlled to 0.1 mm so that 500 kg jumbo spools show < 0.3 % telescoping. ID 150, 200, 300, 500 mm; OD up to 1 200 mm – fits both German and Asian foil winders without reel change.

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Luoyang Xinzhaohe Standard vs. Common Market Quality

Critical Parameter	Unit	Xinzhaohe Spec	Typical Market	Test Method
Al purity (1350)	%	≥ 99.50	99.45–99.49	ASTM E1251
Conductivity @ 20 °C	MS m⁻¹	≥ 34.5 (62.8 % IACS)	33.0–34.0	IEC 60404-2
Elongation (O-temper)	%	≥ 35	25–30	ASTM E8
Burr height after slit	µm	≤ 5	10–30	Optical CCD
Pin-hole count	# m⁻¹	≤ 3	5–10	IEC 60851-5
Enamel concentricity	%	85 ± 5	70–80	Capacitance
Breakdown voltage (single coat)	kV	≥ 2.0	1.2–1.6	IEC 60851-5
Spool telescoping	mm	≤ 0.3 % OD	0.8–1.2 %	Caliper

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Factory-Direct Advantage

By integrating rod drawing through spooling under one 60 000 m² roof in Luoyang, we eliminate intermediate annealing/rewinding costs that inflate European or Japanese prices by 12–18 %. Lead time: 3 weeks ex-works; 20 ft FCL can mix 20 mm–1 200 mm widths to maximise your coil-loading factor. Every spool ships with a QR-coded test dossue – your QA team can trace resistivity, elongation, and breakdown back to the cast lot in < 30 s.

Choose Luoyang Xinzhaohe when “good enough” isn’t good enough for your 220 °C foil-wound transformers.

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Packaging & Global Logistics

Export Packaging & Logistics

Luoyang Xinzhaohe Aluminum Co., Ltd. – 20 Years of Transformer-Grade Foil & Wire Delivered Worldwide

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H3 1. Packaging Philosophy – Zero-Defect at Destination

Transformer-grade 1350 HO foil and enameled wire are stress-sensitive; a 2 µm dent or 0.1 % residual moisture can shift losses by >0.3 %. Our packaging is therefore treated as the last manufacturing step, not an after-sales cost.

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H3 2. Foil & Strip Packaging Specification

Parameter	0.2–0.8 mm Thick Foil	0.8–3.5 mm Strip
Coil OD, max	1 400 mm	1 600 mm
Coil weight	80–250 kg	250–500 kg
Core ID	150 / 200 / 300 mm aluminum or steel	same
Interleaf	0.08 mm HDPE film, one turn every layer	same
Edge protector	3 mm V-groove cardboard, 360°	same
Radial wrap	VCI 80 µm film, 2 layers	same
Desiccant	8 units × 50 g silica gel, ΔW ≤ 1 g H₂O per coil	same
Pallet	fumigated ISPM-15 spruce, 1 200 × 1 000 mm, 4-way entry	same
Strapping	PET + steel corner, 3 circumferential + 2 axial	same
Stack height	2 coils max per pallet, total ≤ 1.8 m	1 coil max
Container load	10 t / 20’GP, 22 t / 40’HC	9 t / 20’GP, 20 t / 40’HC

Result: <0.05 % moisture regain after 45 days at 95 % RH, validated by SGS sea-trial report 2023-TF-11047.

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H3 3. Enameled Wire Packaging Specification

Wire Ø (mm)	Spool Type	Spool Material	Net Weight	Outer Carton	Pallet Pattern
0.2–0.8	PT-4 plastic	ABS, 250 mm flange	10 kg	5-ply kraft, 265 × 265 × 280 mm	12 cartons/layer, 5 layers, 600 kg/pallet
0.8–2.0	PT-10 plastic	ABS, 400 mm flange	30 kg	5-ply kraft, 420 × 420 × 320 mm	6 cartons/layer, 4 layers, 720 kg/pallet
2.0–5.0	DIN-355 steel	galvanized, 355 mm	50 kg	VCI bag + corner board	4 spools/layer, 3 layers, 600 kg/pallet

Each spool is vacuum-sealed with 2 g desiccant, then over-wrapped with 80 µm VCI film. Shock indicator labels (25 G) are applied; if triggered, automatic claim & replacement is triggered under our Zero-Scratch Warranty.

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H3 4. Logistics Chain – Luoyang to Your Dock

1. Origin: 35 km from Luoyang Longmen Rail Hub, 150 km from Zhengzhou International Airport.
2. Export clearance: E-port filing ≤ 4 h, AES bonded warehouse 2 000 m² on site.
3. Sea freight: Weekly FCL service via Qingdao & Shanghai to Hamburg, LA, Dubai, Chennai—transit 18–26 days.
4. Insurance: All-risk coverage up to 110 % of CIF value with PICC.
5. CO₂ footprint: 0.28 t per ton foil, 38 % lower than EU mill average (EcoVadis 2023 score 68/100).

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H3 5. Cost Advantage – Premium Quality without Premium Price

By integrating rod casting, rolling, annealing and in-line eddy-current testing in one Luoyang campus, we remove 2 middle-margin layers typical of Western traders.
Typical saving vs. EU mill: 8–12 % on 5 t order, 14–18 % on 50 t annual contract—while meeting IEC 60317-0-2, ASTM B230, and EN 13601 conductivity specs.

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Next Step: Send us your monthly foil/strip forecast and destination port; we return a door-to-door logistics cost matrix within 24 h.

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Sourcing from Luoyang Xinzhaohe

Why Partner with Luoyang Xinzhaohe for Transformer-Winding Aluminium Foil

20-Year Industrial Pedigree—Not a Trading House

Since 2003 our Luoyang campus has operated a single-site, ISO-9001/ISO-14001 integrated mill that converts 1350/1070/1060 molten metal directly into precision foil.
No toll-processing, no middle-margin—every coil is melted, cast, hot-rolled, cold-rolled, slit and degreased under one roof.
This vertical control gives transformer OEMs three irrefutable advantages:

Benefit	Typical Trader/Broker	Luoyang Xinzhaohe
Lot-to-lot chemistry repeatability	±0.15 % Si max variation	±0.03 % Si (ICP per cast)
Resistivity guarantee	≤ 0.027 Ω·mm²/m (occasional)	≤ 0.027 280 Ω·mm²/m, 100 % coils tested
Traceability	Warehouse label only	Cast # → Hot-roll # → Slit #, barcode on every core
Technical file retention	1 year	10 years, available on request

Direct Factory Pricing—Engineered, Not Negotiated

Our cost structure is benchmarked against LME primary aluminium plus a fixed conversion fee published quarterly—no surprise surcharges.
Because we draw our own 9.5 mm rod and anneal in-line, we save 4–6 % compared with European foil mills that purchase reroll stock.
Those euros stay in your BOM. Typical 2024 reference:

Alloy-Temper	Thickness 0.3 mm, Width 240 mm, ID 500 mm, EDGEBURR ≤ 0.02 mm	FOB Qingdao (USD/kg)	Lead-time
1350-O	0.3 × 240 mm, burr-free, chamfer 0.3 × 45°	3.85	15 days
1070-O	0.2 × 100 mm, high-ductility (A50 ≥ 35 %)	3.78	12 days
1060-O	0.8 × 600 mm, conductivity ≥ 62.7 % IACS	3.70	18 days

Prices valid for 5 t minimum; larger call-offs lock alloy surcharge for 6 months.

Customisation Without MOQ Penalty

Transformer designs are shrinking and voltage classes are splitting—so we built a “micro-slitting” line (width 20–1 600 mm) that changes set-up in < 15 min.
Edge conditioning options:

Edge profile	Ra (µm)	Burr height (µm)	Typical use
Round chamfer 0.2–1.0 mm	≤ 0.4	≤ 20	Layer wind, ≤ 1.1 kV
Full-radius R = ½ thickness	≤ 0.3	≤ 10	Foil-wound HV, ≥ 33 kV
Square-cut	≤ 0.6	≤ 40	Low-voltage reactor

Surface cleanliness: residual oil ≤ 6 mg/m² (Wilhelm test), compatible with vacuum drying at 160 °C.
Inner diameters 150, 200, 300, 400, 500 mm or custom; outer ≤ 1 400 mm, weight ≤ 3 t to suit robotic pay-off.

Quality Gate Aligned to IEC 60317-0-3 & ASTM B373

Every master coil passes:

1. Eddy-current thickness scan—tolerance ±1 %, map supplied.
2. 100 % breakdown voltage at 23 °C, 50 Hz, 20 mm sphere electrodes—guarantee ≥ 1.2 kV for 0.2 mm foil.
3. Elongation & tensile per EN 485-2, values printed on certificate.
4. Packaged in VCI film + HDPE sleeve; desiccant + humidity card; seaworthy plywood pallet.

Premium Alternative to Western Mills—Data Speaks

A 2023 third-party audit by a German tier-1 OEM showed our 1350-O 0.3 mm foil achieved:
Space factor 96.8 % (same lot from a Scandinavian mill: 96.5 %).
Short-circuit axial force test 350 kN/m, no buckling (design limit 320 kN/m).
Total cost landed Europe 8.4 % below their incumbent Nordic supplier.

Next Step—Get the Full Technical Datasheet

Send your foil specification (alloy, temper, thickness, width, edge, annual volume) to cathy@transformerstrip.com.
We return a detailed datasheet, packaging drawing and firm FOB/CFR quote within 24 h.
Prototype slits available from 100 kg; production lead-time 10–18 days, sea freight 22 days to EU or 18 days to US West Coast.

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