Transformer Radiator

Transformer Radiator Manufacturer | Pressed Steel & Hot-Dip Galvanized Radiators for Power Transformers

We manufacture pressed steel transformer radiators for oil-immersed distribution and power transformers up to 500kV. Produced with automated roll-forming and seam-welding lines, each panel section undergoes 100% air-pressure leak testing, internal flush cleaning, and multi-stage corrosion protection. We build standard DIN/EN compliant designs and custom configurations built to client engineering drawings.

Product Range

Radiator Type	Panel Width	Center Distance (L)	Surface Finish Options	Primary Application
Conventional Radiator	520 mm / 480 mm / 310 mm	500 mm to 4000 mm	Primer + Epoxy Topcoat / Polyurethane (C3 to C4)	Standard oil-immersed power and distribution transformers
Hot-Dip Galvanized Radiator	520 mm / 480 mm / 310 mm	500 mm to 3500 mm	Hot-Dip Galvanized (ISO 1461, Zinc layer >= 80 um)	Coastal, offshore, industrial, and high-humidity environments (C4 to C5)
Gooseneck Radiator	520 mm / 480 mm	800 mm to 3000 mm	Epoxy Painted / Hot-Dip Galvanized	Substation layouts requiring clearance around valves, pipes, or oil conservator lines
Fixed / Removable Radiator Elements	Custom Panel Configurations	Per drawing requirements	Liquid Paint / Powder Coating / HDG	Direct header-tank welding or flanged mounting via butterfly valves

Technical Specifications

Sheet Material	Cold-rolled steel DC01 / ST12 / Q235 (EN 10130 compliant)
Sheet Thickness	1.0 mm / 1.2 mm (Standard); 1.5 mm (Heavy-duty reinforced)
Element Width	310 mm, 480 mm, 520 mm
Center Distance Range	500 mm to 4000 mm (Custom increments)
Header Pipe Outer Diameter	70 mm, 88.9 mm, 108 mm, 114 mm
Flange Connections	Standard DIN 42559, EN 50216-6, or ANSI / custom drilled flanges
Design Operating Pressure	100 kPa (1.0 bar)
Factory Leakage Test Pressure	150 kPa (1.5 bar) for 20 minutes (100% pneumatic/hydraulic tested)
Internal Cleanliness	Oil flushing and blast cleaned; particle count compliant with transformer oil standards
Paint System Thickness	Dry Film Thickness (DFT) 120 um to 250 um based on customer paint specification

Custom Manufacturing to Drawings

Drawing Submission: Send CAD (DWG/DXF) or PDF files including center distance, header dimensions, panel count, flange orientation, and paint specifications.

Engineering Review & DFM: We evaluate panel pitch, oil flow restriction risk, and weld access points. Approval drawings are issued within 24 to 48 hours.

Tooling & Jig Alignment: Automated CNC punching and dedicated assembly jigs lock header pipe pitch tolerances within +/-1.0 mm.

Prototype or Batch Fabrication: First-article inspection reports (FAIR) provided for OEM batch production sign-off.

Manufacturing Process & Quality Control

Automated Roll-Forming & Spot Welding: Cold-rolled steel sheets are formed into hydrodynamically optimized oil channels and spot-welded using multi-point automatic welding stations to maintain uniform plate gap.

Continuous Seam Welding: Panel outer edges are sealed using automated CNC resistance seam welders, eliminating manual weld gaps and stress concentration zones.

Header Pipe Assembly: Panel groups are robotic TIG/MIG welded to seamless steel header pipes for full penetration joints.

100% Pressure & Air-Tightness Testing: Every completed radiator assembly is submerged in water testing tanks or pressure-monitored under 150 kPa compressed air for 20 minutes to verify zero micro-fissure leakage.

Internal Flushing & Decontamination: Radiators undergo solvent flushing and hot transformer oil rinsing to remove internal mill scale, moisture, and micro-particles. Internal surfaces are protected with rust-inhibiting oil prior to sealing.

Corrosion Protection & Surface Coating: External surfaces undergo shot blasting (Sa 2.5 grade). Coating options include hot-dip galvanizing at 450 deg C or multi-pass electrostatic painting with salt spray resistance exceeding 1,000 hours (ISO 9227).

Applications

Power Generation & Transmission Substations

Main cooling banks for 110kV, 220kV, and 500kV step-up/step-down power transformers.

Industrial Distribution Transformers

Radiator assemblies for factory distribution units, arc furnace transformers, and mining sub-stations.

Offshore & Renewable Energy Infrastructure

Hot-dip galvanized radiator banks installed on offshore wind turbine platforms and solar PV inverter stations.

Transformer Repair, Overhaul & Retrofit

Replacement cooling panels manufactured to match legacy dimensions during transformer life-extension programs.

How to Select the Right Radiator Component

Thermal Dissipation & Surface Area: Determine required heat dissipation in kW. Adjust radiator width (520 mm standard versus 310 mm compact), total panel count, and center-to-center distance to match transformer oil natural (ONAN) or oil forced (OFAF) circulation rates.

Corrosion Classification (ISO 12944):

C3 (Inland / Standard): Double-coated wet paint system or electrostatic powder coat (DFT 120 to 160 um).
C4 to C5 (Coastal / Marine / Chemical): Hot-dip galvanizing per ISO 1461 with minimum 80 um zinc thickness, or high-solid epoxy/polyurethane marine systems.
Mechanical Interface: Specify weld-on header pipes or detachable flanged connections (DIN 42559 square/rectangular flanges or ANSI round bolt patterns). Verify valve clearance for maintenance routines.
Layout Clearance: Utilize gooseneck offset configurations when straight headers interfere with high-voltage bushings, neutral ground bars, or oil sampling valves.

Packaging & Delivery

Internal Protection

Header pipe oil ports and flange faces are fitted with gasket-sealed plastic transport covers or metal blanking plates to prevent moisture entry and internal contamination during transit.

Structural Crating

Radiator assemblies are stacked on heavy-duty steel frame skids or reinforced fumigated wooden pallets (ISPM-15 compliant).

Inter-Panel Cushioning

Rubber spacers and protective foam sheets are placed between radiator fins to prevent paint abrasion and mechanical distortion during ocean freight handling.

Lashing & Container Loading

Crates are braced with heavy-duty strapping inside 20ft/40ft HQ containers to withstand movement during international transit.

Honor Certificates

FAQ

Q: What pressure testing standards are applied prior to shipment?

A: Every finished radiator undergoes 100% factory pressure testing at 150 kPa (1.5 bar) for a minimum of 20 minutes under water or via pressure-drop monitoring. Pressure test certificates are provided with the shipping documentation package.

Q: How do you guarantee internal cleanliness before the radiator is connected to a transformer?

A: Radiators undergo internal shot-cleaning, high-pressure air cleaning, and hot-oil flushing to remove micro-particles and weld debris. Headers are sealed immediately after inspection with rubber-gasketed transport covers. Internal particulate levels meet IEC 60422 cleanliness standards for transformer oil circuits.

Q: Can you match exact mounting center distances and flange dimensions of old radiators for replacement projects?

A: Yes. Send us your existing radiator layout, header pipe diameter, center-to-center distance, and flange bolt circle specs. We produce direct drop-in replacement units without requiring modifications to your transformer tank connections.

Q: What coating specification do you recommend for high-corrosion or coastal sites?

A: For coastal or C4/C5 marine environments, we recommend Hot-Dip Galvanizing per ISO 1461, achieving a minimum zinc layer thickness of 80 um. Alternatively, a 3-layer epoxy-polyurethane wet paint system (DFT >= 200 um) tested to 1,000+ hours salt spray exposure provides durable corrosion resistance.

Q: What is the standard sheet thickness for pressed steel cooling panels?

A: Our standard manufacturing uses 1.2 mm cold-rolled steel (DC01 / ST12) to balance structural rigidity, thermal dissipation efficiency, and weight. We also process 1.0 mm sheet steel for light-duty applications or 1.5 mm steel for heavy-duty/reinforced requirements.

Q: How are header ports sealed to prevent moisture ingress during shipping?

A: All header openings and flange interfaces are sealed with high-grade rubber gaskets backed by bolted steel cover plates or plastic blind plugs. This preserves internal cleanliness and dry conditions throughout sea transit and site storage.

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