Hot Metal Spray

Thermal metal spray creates a tightly bonded metallic coating over correctly prepared steel. Extend asset life with zinc, aluminium and zinc-aluminium thermal spray systems engineered for demanding Australian Aggressive and corrosive environments.

01

Long-term asset protection

Metallic coatings defend steel in marine, industrial and severe atmospheric exposure.

02

Workshop or on-site delivery

Suitable for new fabrication, large assets and maintenance work that cannot be hot-dip galvanised.

03

Complete duplex systems

Metal spray can be sealed and topcoated for added barrier protection, colour and durability.

SERVICE OVERVIEW

Corrosion Protection Built for Harsh Service

State Steel Treatment provides hot metal spray – also known as thermal metal spray, metallising, zinc spraying or aluminium spraying – as a durable corrosion protection solution for structural steel and industrial assets. The process deposits a continuous metallic coating onto abrasive-blasted steel, helping protect the substrate from moisture, salt, industrial pollutants and atmospheric corrosion.

The service can be delivered as a stand-alone metallic coating or as part of a duplex system incorporating a sealer, tie coat and protective finish coat. This allows the system to be tailored to the environment, required design life, appearance, maintenance strategy and project specification.

A practical alternative for difficult steelwork

Because the coating is sprayed directly onto the prepared surface, hot metal spray can be used on large fabricated items, completed structures and existing assets that are unsuitable for immersion in a galvanising bath.

PROCESS

What Is Hot Metal Spray?

In the thermal spray process, metal wire is fed into specialist equipment and melted using an electric arc or flame. Compressed air atomises the molten metal and projects it onto the prepared steel. The droplets rapidly solidify and build a dense, adherent metallic layer without significantly heating the entire steel component, contrary to the galvanising process.

The bond is primarily mechanical, making surface cleanliness and profile critical. Correct abrasive blasting, controlled application technique and prompt sealing are central to achieving a reliable corrosion protection system.

PERFORMANCE

How the Coating Protects Steel

Sacrificial protection

Zinc-containing coatings can corrode preferentially to exposed carbon steel, helping protect small damaged areas or discontinuities.

Barrier protection

Aluminium and sealed metallic coatings restrict the movement of water, oxygen and salts to the steel surface.

Stable protective films

Aluminium develops a stable oxide layer that supports performance in many marine and industrial exposures.

Duplex performance

Sealers and compatible topcoats reduce porosity, improve appearance and add an additional barrier to the environment.

SYSTEM OPTIONS

Select the Right Metal for the Exposure

Hot metal spray is not a one-size-fits-all coating. The appropriate metal, thickness and post-treatment should be selected from the project environment, expected service life, operating temperature, geometry, accessibility and maintenance requirements. State Steel Treatment can work with the client, engineer, coating manufacturer and project specification to deliver the nominated system.

Zinc

Protection characteristics

Strong sacrificial action helps protect exposed steel at small discontinuities and damaged areas.

Typical use considerations

Commonly selected for atmospheric corrosion protection where cathodic performance is a priority.

Aluminium / TSA

Protection characteristics

Develops a durable barrier and stable oxide film, with strong performance in many marine and industrial environments.

Typical use considerations

Often considered for marine, offshore, process and elevated-temperature duties, subject to the project specification.

Zinc-aluminium alloy

Protection characteristics

Combines sacrificial protection with aluminium’s barrier characteristics.

Typical use considerations

A versatile option where the designer seeks a balance of galvanic and barrier protection.

Important: The final system and dry film thickness must be project-specific. The table above is general guidance and is not a substitute for a corrosion protection specification.

Key Benefits of Hot Metal Spray

Key Benefits of Hot Metal Spray

APPLICATIONS

Where Hot Metal Spray Is Used

Thermal metal spray is suited to both new fabrication and maintenance projects. It is particularly valuable where steel is exposed to salt, moisture, condensation, pollutants or difficult maintenance access – and where a long-life corrosion protection strategy is required.

Structural steel & bridges

Girders, trusses, columns, handrails and exposed steelwork.

Marine & coastal assets

Wharves, jetties, port infrastructure and salt-laden environments.

Mining & materials handling

Conveyors, frames, chutes, supports and process equipment.

Oil, gas & industrial

Pipelines, vessels, skids, plant structures and terminal infrastructure.

Water & wastewater

Treatment plant steelwork, tanks, access structures and pipe supports.

Energy & infrastructure

Transmission structures, renewable projects and heavy civil assets.

Why Choose State Steel Treatment?

Established in 1990, State Steel Treatment delivers protective coating and surface preparation services for construction, mining, oil and gas, marine, water treatment, industrial, commercial and government clients. Hot metal spray expands this capability with a metallic corrosion protection option for demanding assets and long-life specifications.

Complete service

Abrasive blasting, thermal metal spray, sealing, topcoating and inspection can be coordinated through one experienced contractor.

Quality documentation

Project-specific inspection and reporting can be aligned with the specification and client hold points.

Corrosion-focused advice

System selection is approached from the asset environment, design life and maintenance needs – not simply the application method.

Workshop and site solutions

Flexible delivery for new fabrication, large assets, shutdowns and maintenance projects.

QUALITY-CONTROLLED EXECUTION

Our Hot Metal Spray Delivery Process

A thermal spray system performs only as well as its surface preparation, application control and inspection. State Steel Treatment integrates the hot metal spray process with established abrasive blasting, protective coating and inspection capabilities to provide a complete corrosion protection package.

1

Project review and system selection

Confirm the substrate, exposure, design life, access, metal, thickness, sealer and topcoat requirements.

2

Surface preparation

Remove contaminants and abrasive blast to the specified cleanliness and angular profile. Spray promptly to minimise flash rusting or contamination.

3

Thermal metal spray application

Melt metal wire by arc or flame, atomise it with compressed air and build a uniform coating using controlled passes.

4

Sealing and topcoating

Apply a compatible sealer promptly. Add a tie coat and finish coat where the specified duplex system requires them.

5

Inspection and documentation

Verify preparation, conditions, thickness, visual finish, adhesion and repairs against the inspection and test plan.

VERIFICATION

Inspection and Quality Assurance

Inspection requirements are established through the project specification and inspection and test plan. Depending on the scope, quality records may include:

FLEXIBLE PROJECT DELIVERY

Workshop and On-Site Capability

State Steel Treatment can coordinate hot metal spray with abrasive blasting, protective coatings and independent inspection requirements. Work can be planned for workshop fabrication, large components and controlled on-site maintenance scopes, subject to access, containment, ventilation, environmental controls and project safety requirements.

Standards-based delivery

Systems can be specified and executed with reference to AS/NZS 2312.3:2025, ISO 2063-1:2019, ISO 2063-2:2017 and AWS C2.23M/C2.23:2018 / NACE No. 12 / SSPC-CS 23.00, together with the client specification and coating manufacturer requirements.

Protect Your Steel with Hot Metal Spray

Speak with State Steel Treatment about a project-specific thermal metal spray system for your asset.

Address

24 Tattersall Road, Kings Park NSW 2148

Phone

(02) 9622 5544

Office Hours

Mon - Fri: 7:00am - 2:00pm Saturday by appointment

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