Hot Dip
Galvanizing
Steel Source Australia arranges structural galvanizing, spin galvanizing, duplex coating and powder coating services for fabricated steel across Queensland, New South Wales, Victoria and Tasmania. Submit your drawings and quantities and we'll coordinate the rest.
Coating Services
Available Services
Steel Source Australia can arrange the following coating services for your fabricated steel. Contact us with your drawings, dimensions and quantities.
Hot Dip Galvanizing
Structural & general fabrications
Steel is submerged in molten zinc at ~450 °C, forming a metallurgical bond between the zinc and steel. The resulting coating provides cathodic (sacrificial) protection — zinc corrodes preferentially, protecting the underlying steel even at cut edges and scratches. Zinc bath sizes up to 14 m long × 2 m wide × 2.9 m deep; fabrications up to 19 m via double dip.
AS/NZS 4680Spin Galvanizing
Small parts — fasteners, hinges, brackets
Centrifuge (spin) galvanizing for small components including fasteners, hinges, washers, brackets and fittings. Parts are loaded into a perforated basket, dipped in the zinc bath, then centrifuged to remove excess zinc and prevent bridging between threads. Consistent coating thickness on complex geometries.
AS 1214 / ASTM A153Duplex Coating
Galvanizing + powder coat combined
A duplex system combines hot dip galvanizing with a powder coat or liquid paint topcoat. The galvanizing provides cathodic protection; the topcoat provides a barrier and colour. Duplex systems extend service life 1.5–2.3 times the sum of each system alone. Ideal for architectural, decorative and high-corrosion applications.
AS/NZS 4506Below Grade Coating
Underground and buried steel
Specialist coatings for steel anchored below ground — utility towers, communication towers, foundation piles and ground anchors. Protects against the corrosive effects of soil chemistry and underground moisture where standard galvanizing alone may not provide sufficient protection.
Project specificPowder Coating
Colour, texture and barrier protection
Electrostatically applied dry powder cured under heat to form a hard, durable finish. Wide selection of primer coats, clear coats, textured surfaces and colours. Can be applied over galvanizing (duplex) or direct to steel. Suitable for architectural, decorative and industrial applications.
AS 4506 / AS/NZS 4506Deglaring
Reduced reflectivity on galvanized steel
A chemical or mechanical process to reduce the bright reflectivity of freshly galvanized steel. Enables galvanized structures to blend into wooded, arid or sensitive visual environments without sacrificing corrosion protection. Commonly specified for transmission towers, rural structures and environmentally sensitive projects.
Project specificProcess
The Galvanizing Process
01
Surface Preparation
Steel is degreased, pickled in acid to remove mill scale and rust, then fluxed to prevent re-oxidation before dipping. Clean steel is essential for a quality galvanized coating.
02
Galvanizing
Prepared steel is submerged in a bath of molten zinc at approximately 450 °C. A metallurgical bond forms between the zinc and steel, creating a series of zinc-iron alloy layers topped with pure zinc.
03
Inspection
Coating thickness is measured using a magnetic gauge to verify compliance with AS/NZS 4680. Minimum average coating thickness for structural steel is 85 µm; minimum local thickness is 70 µm.
04
Delivery
Galvanized steel is cooled, inspected and prepared for collection or delivery. Expedited 24-hour turnaround is available on request at most facilities — contact us for details.
Network
Australian Locations
Galvanizing facilities are strategically located close to major construction and industrial hubs across Australia. Contact us to confirm the most suitable facility for your project.
Brisbane (Carole Park)
QLD
Wacol Industrial Estate, western suburbs of Brisbane. Structural and general fabrications.
Structural kettleBrisbane (Pinkenba)
QLD
Eastern suburbs adjacent to Brisbane Airport. 10.7 m structural kettle; double dip up to 18 m.
10.7 m kettleSydney (Girraween)
NSW
Adjacent to Great Western Highway. 12.5 m structural kettle; columns and beams up to 18 m. Centrifuge (spin) kettle for small parts.
12.5 m kettleNewcastle (Hexham)
NSW
Junction of Pacific and New England Highways. Heavy structural parts up to 20 tonnes.
Heavy structuralPort Kembla
NSW
Consolidation point for Wollongong, Illawarra and South Coast regions. Pick-up and drop-off.
Consolidation depotMelbourne
VIC
Northern Melbourne with excellent freeway access from all directions.
Structural kettleTasmania (Launceston)
TAS
Northern Tasmania. 6.5 m structural kettle; double dip up to 9.5 m.
6.5 m kettleExpedited 24-Hour Turnaround Available
Fast-track galvanizing turnaround available on request at most Australian facilities. Contact us for details and availability.
Technical Reference
Design for Galvanizing
Steel fabrications must be designed to allow molten zinc to flow freely in and out of all cavities. Poor design leads to uncoated areas, zinc pooling, distortion and safety hazards. Key design requirements per AS/NZS 4680:
Venting and Drainage Holes
All hollow sections, box members and closed cavities must have vent holes at the highest point and drain holes at the lowest point. Minimum hole diameter: 12 mm for sections up to 100 mm; 25 mm for larger sections. Holes must be positioned to allow complete zinc drainage — no trapped zinc pools.
Avoid Overlapping Surfaces
Overlapping plates, back-to-back angles and lap joints trap flux and moisture, causing steam explosions in the zinc bath. All overlapping surfaces must be seal welded (continuous weld) or have adequate gaps (minimum 3 mm) for flux drainage. Intermittent welds on overlapping surfaces are not acceptable.
Distortion Prevention
Asymmetric fabrications and thin plate assemblies are susceptible to distortion during galvanizing due to thermal stresses. Use balanced weld sequences, adequate bracing and symmetric cross-sections. Thin plate (< 6 mm) welded to heavy sections is particularly prone to distortion.
Threaded Components
External threads (bolts) should be galvanized and tapped oversize to allow for coating thickness. Internal threads (nuts) should be tapped after galvanizing or use hot dip galvanized nuts with oversize tapping. Spin galvanizing is preferred for fasteners as it produces a thinner, more uniform coating.
Maximum Kettle Dimensions
Fabrications must fit within the available kettle dimensions at the selected facility. Typical structural kettles range from 6.5 m to 12.5 m; double dip extends reach to 18–19 m. Confirm dimensions with the facility before fabrication.
Surface Condition
Mill scale, paint, galvanizing, weld slag and heavy rust must be removed before galvanizing. The pickling process removes light rust and mill scale but cannot remove heavy paint or weld spatter. Fabrications should be delivered clean and free of contaminants. Weld spatter must be ground off.
Applicable Standards
AS/NZS 4680
Hot Dip Galvanized Coatings on Ferrous Articles
The primary Australian standard for hot dip galvanized coatings. Specifies minimum coating thickness requirements, inspection methods, and acceptance criteria for galvanized steel fabrications.
AS 1214
Hot Dip Galvanized Coatings on Threaded Fasteners
Specifies requirements for hot dip galvanized coatings on externally threaded fasteners (bolts, screws, studs) and internally threaded fasteners (nuts). Covers coating thickness, thread tolerances and testing.
AS/NZS 4534
Zinc and Zinc/Aluminium Coatings on Steel Wire
Specifies requirements for zinc and zinc/aluminium alloy coatings on steel wire. Referenced for galvanized wire products including chainwire fencing, welded mesh and gutter guard mesh.
AS/NZS 4600
Cold-Formed Steel Structures
References galvanizing requirements for cold-formed steel structural members. Specifies minimum coating thickness for structural applications and design considerations for galvanized cold-formed sections.
AS 4312
Atmospheric Corrosivity Zones in Australia
Defines atmospheric corrosivity categories (C1–C5 and CX) for locations across Australia. Used to determine the appropriate coating system and expected service life for galvanized steel in different environments.
ISO 1461
Hot Dip Galvanized Coatings on Fabricated Iron and Steel Articles
International standard for hot dip galvanized coatings. Equivalent to AS/NZS 4680 for most purposes. Referenced on international projects and for export fabrications.
Get Started
Need Your Steel Galvanized?
Contact Steel Source Australia with your fabrication drawings, dimensions and quantities. We'll arrange collection, galvanizing and return delivery — or advise on the nearest facility for direct drop-off.