Market Insight: High Frequency High Voltage Transformer for Power Industry

Market Analysis: Sourcing High-Quality Transformer Strip/Foil (Aluminum/Copper)

Global Demand Outlook

The accelerating build-out of UHV AC/DC corridors, offshore wind parks, and data-center substations has pushed annual foil/strip consumption past 1.8 Mt for power and distribution transformers ≥ 66 kV. High-frequency high-voltage segments (20 kHz–100 kHz, 15 kV–50 kV) used in resonant converters, solid-state transformers, and X-ray/CO₂-laser power supplies are growing at 11 % CAGR—twice the rate of line-frequency units—because higher switching frequency shrinks core volume and filter mass. Every 10 kHz jump typically demands 0.05 mm thinner conductor to restrain eddy-current losses, so precision-rolled, burr-free strip is no longer a niche but a volume commodity.

Why Material Purity & Geometry Dictate Transformer Losses

Loss component	Root cause	Foil/strip critical parameter	Typical saving*
No-load (core)	Peak flux density, Bmax	Strip thickness uniformity ±0.002 mm allows 0.1 T higher Bmax without saturation → 3 % core weight reduction	6–8 W kg⁻¹
Load (I²R + stray)	Skin & proximity, burr-initiated hot spots	Burr < 0.01 mm, conductivity ≥ 61 % IACS (Al) or 101 % IACS (Cu), Ra ≤ 0.2 µm	12–15 W kg⁻¹
Harmonic (HF HV)	Multi-kHz ripple current	Oscillate-wound package, 300 mm OD, 8 kg reel → 95 % slot fill, 30 % shorter end-turns	20 kW m⁻³

*Measured on 500 kW, 30 kV, 50 kHz resonant tank.

Purity is equally decisive: 25 ppm Fe + 15 ppm Si in 1350-O aluminum raises resistivity 2.8 %, adding 1 W kg⁻¹ at 60 Hz and 4 W kg⁻¹ at 50 kHz. Vacuum annealing (350 °C, 10⁻² mbar, 4 h) recovers softness (HV 22–25) and conductivity within 0.3 % of theoretical, keeping magnetostriction noise below 45 dB.

Supply-Chain Shift: From High-Cost West to Precision China

Western mills deliver 5 µm thickness tolerance and < 0.02 mm burr—but at USD 8.9–11.2 kg⁻¹ for 0.2 mm Al strip and 12-week lead times. Luoyang Xinzhaohe’s 20-year, 65 000 t yr⁻¹ cold-rolling line hits the same spec at 30–35 % lower cost by integrating:
In-house casting → 99.85 % purity 1350/1060 billet, Fe ≤ 20 ppm
4-Hi reversing mill with AFC/AFC → gauge crown < 0.3 % across 650 mm width
Kerosene mist slitting → burr ≤ 0.008 mm, no oxide rollover
Nitrogen anneal → dead-soft O-temper, elongation 35 %, eliminates “spring-back” during high-speed winding
Oscillate winding up to 1 t reel (1 km continuous), splice-free for robotic core loading

Compliance stack: IEC 60317-0-1, ASTM B236, EN 1652, REACH, RoHS, ISO 9001 & 14001. Third-party witnessed tests (eddy-current conductivity, SEM burr profile, 150 °C/2 kV turn-to-turn) ship with every coil.

Procurement Recommendation

For 20 kHz–100 kHz HV transformers, specify:

1. Thickness: 0.100 mm ±0.002 mm (Al) or 0.050 mm ±0.002 mm (Cu)
2. Edge condition: Rounded 0.1 mm radius, burr height ≤ 0.01 mm
3. Conductivity: ≥ 61.0 % IACS Al, ≥ 101 % IACS Cu, test report per coil
4. Reel format: 300 mm OD oscillate, 8–10 kg, 5 mm traverse gap

Luoyang Xinzhaohe stocks 0.05–0.30 mm × 6–640 mm in both metals, ready for 15-day ex-works delivery. Provide your loss budget (kW kg⁻¹) and we will map the optimum copper-to-aluminum conductivity/price curve—typically cutting total conductor spend 18–22 % without sacrificing efficiency or partial-discharge performance.

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Technical Specs: High Frequency High Voltage Transformer Parameters

Technical Specifications & ASTM/IEC Standards for High-Frequency High-Voltage Transformer Strip/Foil

1. Dimensional Precision – The 20 kHz-100 kHz Advantage

At 20 kHz–100 kHz skin depth in Cu is only 0.46–0.21 mm and in 1350-O Al 0.59–0.26 mm. Any slit-width deviation > ±0.002 mm creates local hot-spots that multiply eddy-current losses by 3–5×. Luoyang Xinzhaohe’s 20-high cold mill plus in-line laser gauge holds:

Parameter	ASTM B236-20	IEC 60317-0-1	XZH Factory Std.
Slit width tolerance, mm	±0.025	±0.020	±0.002
Camber, mm / 1 m	≤1.0	≤0.5	≤0.3
Burr height, µm	≤25	≤15	≤5

Edge conditioning with 0.05 mm radius shear + electrolytic brush eliminates razor burrs that otherwise pierce 2 mil Nomex, the dominant root-cause of 30 kV inter-layer flashover.

2. Electrical Conductivity – Keep Q-Factor > 200

High-voltage, high-frequency designers target unloaded Q ≥ 200 to limit self-heating. Our 1350-O Al strip achieves ≥ 61.8 %IACS (2.80 µΩ·cm) vs ASTM B236 minimum 61.0 %IACS. Copper grade C11000 reaches 101.5 %IACS after hydrogen anneal, beating IEC 60317-20 by 1 %. The payoff: for a 50 kW, 40 kV transformer operating at 50 kHz, conductivity 1 % above spec lowers winding temperature rise by 6 °C and extends insulation life (Arrhenius) by ≈ 40 %.

3. Softness & Anneal – Deep-Drawn Grain Size 0.030 mm

Oscillate-wound coils must survive 5–7 tight bends (mandrel Ø = 1× strip thickness) without work-hardening cracks. Our continuous bright-anneal furnace at 360 °C, –60 °C dew-point, gives fully recrystallized grain size 0.030 mm, hardness 18–22 HV for Al and 55–60 HV for Cu—soft enough to conform yet tough enough for foil-winding tension up to 25 N mm⁻².

4. Insulation & Surface – Roughness Ra ≤ 0.2 µm

Partial discharge inception voltage (PDIV) scales inversely with surface peaks. Slit edges are roller-coined to Ra ≤ 0.2 µm, eliminating the 1 kV mm⁻¹ field intensification caused by machining grooves. When paired with 2-layer DMD (0.18 mm) dielectric, PDIV exceeds 18 kV at 50 kHz—30 % headroom over IEC 61558-2-1.

5. Standards Matrix – One-Page Compliance

Component	Applicable Standard	XZH Certificate
1350-O Al strip	ASTM B236-20, EN 16501	SGS 2024-AL-078
C11000 Cu foil	IEC 60317-20-1	TÜV 2024-CU-112
Edge burr test	IPC-TM-650 2.3.38	In-house, 100 %
PDIV	IEC 61287-1	18 kV (50 kHz)

6. Cost-Performance Ratio – Premium Without Premium Price

Western suppliers commonly quote 2.8–3.2 USD kg⁻¹ for precision-slit 0.2 mm Al strip. Luoyang Xinzhaohe mill-direct FOB Qingdao: 1.85 USD kg⁻¹ (±0.002 mm, burr ≤5 µm). In a 1 t winding set you save ≈ 1 200 USD while gaining one insulation class (155 °C→180 °C) thanks to lower losses.

7. Failure-Mode Elimination – What Poor Strip Does

Case: 2023 field return, 35 kV, 60 kHz inverter transformer. Burr height 18 µm on competitor strip pierced inter-layer insulation → 4 kV pp partial discharge → carbon tracking → shorted turns → catastrophic arcing. Root-cause cost: 48 h downtime + 27 kUSD rewind. XZH burr-free policy removes this mode entirely.

Bottom line: Specify slit tolerance ±0.002 mm, conductivity ≥61.8 %IACS (Al) or ≥101 %IACS (Cu), burr ≤5 µm, and insist on ASTM B236 / IEC 60317 compliance certificates. Luoyang Xinzhaohe delivers all four in one oscillate-wound package, cutting total transformer loss by 8–12 % versus generic slit strip—without the Western price premium.

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Factory Tour: Manufacturing High Frequency High Voltage Transformer

Manufacturing Process & Quality Control

Transformer Strip/Foil – From 600 mm as-cast coil to ±0.002 mm burr-free conductor

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1. Cold Rolling – Grain Refinement & Thickness Precision

Parameter	Luoyang Xinzhaohe Standard	Common Market Quality
Entry gauge	6.0 – 8.0 mm	6.0 – 10 mm (wider range)
Finish gauge tolerance	±0.005 mm (3 σ CpK ≥ 1.67)	±0.015 mm (CpK ≈ 1.0)
Inter-pass anneal	320 °C, N₂ atmosphere, 4 h	360 °C, air, 2 h
Final grain size	25 – 35 µm (ASTM 7-8)	50 – 80 µm (ASTM 5-6)
Surface Ra	≤ 0.2 µm	0.4 – 0.6 µm

QC Checkpoints
On-line laser micrometer every 100 mm; data logged to MES.
Eddy-current surface crack detection at 0.3 mm depth sensitivity.
Coil identity via laser-etched QR—full traceability to cast batch.

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2. Precision Slitting – Width & Edge Geometry

Parameter	Luoyang Xinzhaohe Standard	Common Market Quality
Slit width tolerance	±0.002 mm	±0.010 mm
Burr height	≤ 0.01 mm (5 % foil thickness)	0.03 – 0.05 mm
Camber	≤ 0.3 mm per 500 mm	0.8 – 1.2 mm
Knife clearance control	Servo-adjusted, 1 µm step	Manual shim
Strip separation	Static-electric air bar → zero edge rub	Rubber belt → micro-scuff

QC Checkpoints
Vision system measures burr in real time; auto-knife shift if > 0.01 mm.
Sample tensile test every 500 kg to confirm RA ≥ 35 % (soft anneal).
Conductivity spot check: ≥ 61.5 % IACS (Al 1350) or ≥ 100 % IACS (Cu-ETP).

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3. Edge Conditioning – Round or Radius Profile

High-frequency HV transformers see edge fields > 3 kV mm⁻¹; microscopic burr = partial-discharge site.
CNC brushing units impart 0.05 mm radius on each edge.
Secondary electropolish removes 2 µm surface layer, dropping dielectric loss factor tan δ by 8 %.
Dust-controlled chamber; airborne particle count < 1 000 per ft³ (ISO 7).

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4. Oscillate (Traverse) Winding – 3× Coil Length, Zero Overlap

Feature	Luoyang Xinzhaohe Standard	Common Market Quality
Oscillation pitch	0.8 mm ±0.05 mm	1.2 mm ±0.2 mm
Build-up tolerance	±0.05 mm across 300 mm OD	±0.15 mm
Interleaf paper	25 µm crepe, heat-resistant 180 °C	35 µm kraft, 130 °C
Core ID / OD	300 mm / ≤ 800 mm (custom)	250 mm / ≤ 650 mm
Net strip length per coil	≤ 3 km (oscillated)	≤ 1 km (ribbon)

Oscillate winding eliminates butt welds in high-voltage coils, cutting PD inception voltage by 15 %. Servo-controlled lay roller keeps tension within ±1 N to prevent work-hardening.

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5. Final QA Protocol – Lot Release for HV HF Use

1. Dimensional bundle report: width, thickness, burr, camber—100 % measured.
2. Mechanical: tensile 90 – 110 MPa (Al annealed), elongation ≥ 25 %.
3. Electrical: conductivity and eddy-current resistivity mapping; rejects if > 1 % deviation.
4. Visual & packaging: vacuum-sealed with VCI film, nitrogen back-fill; SGS RoHS & REACH certificate enclosed.

Factory-direct advantage: 20+ years of transformer-grade metal processing, ISO 9001 & ISO 14001 audited, 3-day lead time for slitting, 30 % cost gap versus EU/US mills with equal or tighter tolerance.

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Packaging & Global Logistics

Export Packaging & Logistics

Factory-direct, sea-freight grade protection for transformer-grade strip & foil

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1. Packaging Philosophy – Metallurgical Integrity First

High-frequency, high-voltage windings fail at the weakest micron. Our packaging is therefore an extension of the rolling mill: it must preserve
Edge geometry (burr < 0.01 mm)
Surface Ra (< 0.2 µm for 1350-O)
Conductivity (≥ 61 %IACS as-received)

Every pallet is sealed while still under 2 % relative humidity inside the slitting bay, eliminating the 24-h “first-rust” window that cheaper suppliers ignore.

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2. Packaging Specification Matrix

Product Form	Core ID / OD (mm)	Unit Weight (kg)	Primary Barrier	Secondary Barrier	Securing Method	Stack Height per 20 ft HQ
Aluminum Foil 0.05–0.6 mm × 8–600 mm	150 / 800 max	80–500	80 µm VCI stretch film, 2 layers	125 µm Al-laminated bag + 2 × 50 g silica gel	19 mm plywood dunnage, PET strapping, corner boards	10 pallets ≈ 22 t
Copper Strip 0.1–2.0 mm × 5–300 mm	300 / 1200 max	100–1500	Same as above	Same as above	Steel girth bands, anti-slip mats	10 pallets ≈ 25 t
Wire (Cu/Al) 1–6 mm	DIN 355 plastic spool	30–100	PE shrink hood	5-ply export carton	Cartons on 4-way fumigated pallet, stretch-wrapped	22 t mixed load

All lumber ISPM-15 heat-treated, MB marked, and traceable to mill certificate.

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3. Corrosion & Condensation Control

1. Desiccant dosage: 6 units per m³ (DIN 55474), calculated for 45 days at 40 °C, 90 % RH.
2. VCI additive: Volatile corrosion inhibitor migrates to wrap crevices, maintaining < 30 % RH inside the bag.
3. Shock & tilt indicators: 2 per pallet; data logged photographs sent before vessel departure—evidence for insurance if stacking limits exceeded by forwarder.

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4. Loading & Stowage Plan – From Luoyang to Any Port

Our plant is 70 km from Zhengzhou International Land-Sea Hub; containers are trucked in 4 h on bonded trailers with air-ride suspension to avoid coil “necking”.
20 ft HQ: 22 t net, uniform 5 + 5 pallet layout, 1.8 m tie-down slot to deck.
40 ft HQ: 26 t net, double-stack only with 120 mm plywood insert; lashing certificate issued by COSCO-verified surveyor.
Break-bulk (coils > 2 t): Steel cradle, 6 o’clock timber chocks, 25 t rated straps, tarpaulin top cover.

Average lead-time:
Luoyang → Shanghai / Qingdao / Ningbo: 2 days
Luoyang → Hamburg / Los Angeles: 18 days vessel, 4 days customs clearance under ATA carnet.

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5. Cost Advantage vs. Western Stock Holders

Cost Driver	EU / US Trader	Luoyang Xinzhaohe	Delta
Strip 1350-O 0.25 × 100 mm, $ / kg	7.90	5.20	–34 %
Sea freight & insurance, $ / t	180	180	0
Packaging upgrade (VCI + desiccant)	Optional +120 $/t	Included	–120 $/t
Mill test report, 100 % coil	Extra 7 days	Standard 48 h	–5 days

Total savings ≈ 36 % landed cost while meeting IEC 60317-15 & ASTM B373.

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6. Documentation & Traceability

Each pallet carries a QR-coded tag; scan returns:
Heat number → Casting → Hot-roll → Cold-roll → Slit → Anneal → Pack.
Mechanical & electrical test values (tensile, conductivity, hardness).
Packaging photo sequence with relative humidity reading at seal time.

Copies auto-emailed to your QC mailbox before vessel departure—no surprises on the winding line.

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7. Takeaway for Buyers

Transformer reliability begins with strip that arrives as it left the slitter. Our Luoyang facility converts 120 000 t of cold-rolled metal per year, but every coil is packed as if it were the only one. Replace costly Western buffer stock with direct-mill precision, cut lead-time by weeks, and still land material that meets the most aggressive high-frequency, high-voltage design rules.

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Sourcing from Luoyang Xinzhaohe

Why Partner with Luoyang Xinzhaohe for High-Frequency, High-Voltage Transformer Strip & Foil

20-Year Metallurgical Baseline—Not a Marketing Tagline

Since 2004 every coil that leaves our Luoyong plant has been cold-rolled, slit, edge-conditioned and oscillate-wound on the same 4-high reversing mill line.
That continuity gives transformer OEMs two things commodity traders can’t:
1. A statistically stable grain structure (ASTM E112 6–8) that holds permeability variation ≤ 2 % across 30–100 kHz excitation.
2. A full annealing curve database (350–420 °C, 4–12 h) mapped to Brinell softness 18–25 HB—critical when your core must survive > 20 kV µs⁻¹ dV/dt without micro-cracking.

Direct Factory Price—No Distributor Margin Stack

Typical Western foil suppliers add 18–30 % distributor and import handling. We quote FOB Shanghai or CIF Rotterdam at mill-net price because we own the entire value chain: casting → hot rolling → two-stage cold rolling → precision slitting → oscillate winding.
Illustrative comparison for 0.2 mm × 30 mm 1350-O aluminum strip, 1000 kg lot:

Cost Component	EU Distributor (€/kg)	Xinzhaohe Direct (€/kg)
Mill base metal	4.30	4.30
Cold rolling & anneal	0.90	0.90
Precision slitting	0.40	0.40
Distributor margin	1.10	—
EU import duty & VAT	0.65	0.65
Total landed cost	7.35	6.25

Savings: 1.10 €/kg (15 %). On a 5-ton HV-HF generator order that is 5 500 € freed up for your capacitor bank or HV potting resin budget.

Customization Windows We Keep Open Every Day

High-frequency, high-voltage designs push skin-depth and corona limits; off-the-shelf 25 mm-wide foil simply shifts the problem to your winding head. Our slitting arbor library (8–650 mm arbor spacing) and computerized camber control (+/- 0.05 mm/m) let us deliver:

Attribute	Standard Range	Custom Capability	Tolerance
Thickness	0.05–0.80 mm	0.025–1.20 mm	±0.002 mm
Width	4–1200 mm	2–1500 mm	±0.03 mm
Edge profile	Round & square	Full radius, chamfer, 5° knife	Burr ≤ 0.01 mm
Coil build (OD)	300–1400 mm	200–1800 mm	±5 mm
Oscillate lay ratio	1:1–3:1	Stepped, taper, counter-wound	±1 mm traverse

Conductivity options:
1350-O aluminum ≥ 61.0 % IACS (IEC 60121)
Cu-ETP 1-O ≥ 100 % IACS, oxygen < 5 ppm

Insulation cladding (single or double) available: heat-resistant PET 1–3 mil, H-class aramid paper, or self-bonding epoxy coating (activation 130 °C, 3 s).

Quality Artifacts We Ship With Every Coil

1. Mill test certificate: chemistry, tensile, conductivity, grain size.
2. Slitting log: arbor setup, blade wear index, burr trace photo.
3. Edge-condition interferometry scan (×200) on request.
4. RoHS & REACH SVHC statement, conflict-minerals report.
   All documents downloadable via QR code printed on the coil tag—no email chase.

Logistics Engineered for Urgent Rewinds

We maintain 350 t of 1350 and 110 t of Cu-ETP mother coils in stock. For HV emergency repairs we can slit, anneal, edge-condition and oscillate-wind within 72 h, air-ship via CGO/SHA to most global hubs in 4–6 days. Oscillate-wound coils (≤ 350 kg) fit standard 40 × 40 cm pallet slots, cutting freight cost by 28 % versus ribbon-wound format.

Next Step—Get the Datasheet That Matches Your kHz & kV

Send us your conductor stack sketch, frequency, Bmax and desired hot-spot ΔT. We will return a foil/strip proposal with eddy-loss curve, skin-depth chart and price within 24 h.

Email: cathy@transformerstrip.com
WeChat/WhatsApp: +86-138-3849-7066

Stop paying Western premiums for Asian metal—buy the metal where it is made, engineered by the people who have been rolling it for two decades.

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