Galvalume Steel - Unionindus

Galvalume steel is carbon steel coated with an aluminum-zinc alloy that provides a durable metallic barrier against atmospheric corrosion. The coating is commonly composed of approximately 55% aluminum, 43.4% zinc, and 1.6% silicon by weight, subject to the applicable product standard. Aluminum contributes long-term barrier protection and heat reflectivity, while zinc supports sacrificial protection at exposed areas. Silicon helps control the coating reaction during production.

The material is produced on a continuous hot-dip coating line. Prepared steel strip passes through the molten aluminum-zinc alloy, after which the coating mass, surface, flatness, and mechanical properties are controlled. The finished product can be supplied as Galvalume steel coil, slit coil, strip, flat sheet, cut-to-length sheet, or substrate for color coating and profiling.

Galvalume steel is widely selected for roofing, wall cladding, prefabricated buildings, HVAC equipment, appliances, agricultural structures, electrical enclosures, and industrial fabrication. Promisteel supplies material according to the buyer's standard, grade, dimensions, coating designation, surface treatment, processing, packaging, and delivery requirements.

Specifications and Grades

Galvalume steel may be ordered to ASTM A792/A792M, EN 10346, JIS G3321, or another agreed specification. Grade and coating selection should match the forming method, structural requirement, exposure environment, expected service life, and intended finish.

Common Standards and Grades

Standard	Common Grade Examples	Typical Use
ASTM A792/A792M	CS Type A/B/C, FS, DDS, EDDS, SS grades	Commercial forming, drawing, and structural applications
EN 10346	DX51D+AZ, DX52D+AZ, DX53D+AZ, DX54D+AZ, S220GD+AZ, S250GD+AZ, S280GD+AZ, S320GD+AZ, S350GD+AZ	Forming and structural aluminum-zinc coated products
JIS G3321	SGLCC, SGLCD, SGLC structural grades	Commercial, drawing, and structural applications

Coating and Surface Options

Specification Item	Requirements to Confirm
Product form	Coil, slit coil, strip, flat sheet, or profiled feedstock
Alloy coating	Standard-specific aluminum-zinc coating designation, such as commonly requested AZ150-class material
Surface appearance	Standard metallic spangle or customer-agreed appearance
Surface treatment	Passivated, resin coated, anti-fingerprint, oiled, unoiled, or agreed treatment
Surface quality	Standard commercial or appearance-controlled surface where available
Edge condition	Mill edge or slit edge
Processing	Slitting, cut-to-length, profiling, corrugating, or other agreed service

Ordering Information

Application Fields

Roofing and Wall Cladding

Galvalume steel is widely used for standing-seam roofs, corrugated roofing sheets, wall panels, roof decks, flashings, gutters, trims, and other building-envelope components. Its metallic coating is suitable for many atmospheric environments when panel design, drainage, fasteners, sealing, installation, and maintenance are properly controlled.

Prefabricated and Light Steel Buildings

Typical uses include warehouses, workshops, agricultural buildings, modular structures, light-gauge framing, purlins, and sandwich-panel systems. Structural grade and thickness must be selected according to the required load and local design code.

HVAC and Industrial Equipment

Galvalume coil and sheet can be formed into ducts, ventilation housings, air-conditioning components, furnace and appliance panels, equipment covers, electrical cabinets, and industrial enclosures. Heat reflectivity and surface durability can be useful in suitable equipment applications.

Color Coated Steel Substrate

Aluminum-zinc coated steel is commonly used as a substrate for prepainted steel, often called PPGL. With compatible pretreatment, primer, topcoat, and back coat, it can provide both decorative appearance and enhanced corrosion protection for roofing, cladding, doors, appliances, and interior panels.

Agriculture, Energy, and General Fabrication

Other applications include grain storage, greenhouse components, farm structures, solar-related backing or mounting components, cabinets, profiles, tubes, and custom fabricated products. Suitability should be reviewed for the actual chemical, coastal, high-temperature, or continuously wet environment.

Product Advantages

Long-Term Atmospheric Corrosion Resistance

The aluminum-rich coating forms a stable barrier that can provide durable protection in many outdoor environments. Zinc in the coating contributes sacrificial protection at small exposed areas. Performance depends on coating mass, climate, drainage, cut edges, installation, and maintenance.

Heat Reflectivity

The aluminum component gives Galvalume steel useful solar and thermal reflectivity. This characteristic can benefit roofing and equipment applications, although complete thermal performance also depends on insulation, ventilation, roof design, surface aging, and any color coating.

Suitable for Roll Forming

Appropriate grades can be cut, bent, roll formed, corrugated, stamped, and assembled into panels and components. Buyers should state the forming severity and minimum bend radius so that substrate properties and coating behavior can be reviewed.

Good Base for Prepainted Products

Galvalume steel is a widely used substrate for PPGL and other factory-coated products. A correctly designed paint system can provide color, weather resistance, and architectural appearance while using the metallic layer as additional corrosion protection.

Efficient Production and Coverage

Coil form supports continuous profiling and high-volume manufacturing. Galvalume steel can be used in lightweight panel systems that provide broad coverage with efficient material use when properly designed.

Recyclability and Lifecycle Value

The steel base remains recyclable. In suitable applications, durable metallic protection and reduced maintenance can contribute to favorable lifecycle value.

Packaging and Transportation

Galvalume steel surfaces must be protected from moisture, impact, abrasion, edge damage, and movement during transport. Packaging should match the product form, surface requirement, package weight, shipping method, destination climate, and unloading equipment.

Coil Packaging

Coils may be wrapped with moisture-resistant paper or protective film and fitted with inner and outer steel covers, edge protectors, steel straps, labels, and skids. Eye-to-sky or eye-to-side packing can be arranged according to loading and unloading requirements. Coil packages must be properly blocked and lashed for container, truck, rail, or breakbulk shipment.

Sheet Packaging

Sheets are generally stacked in aligned bundles with waterproof wrapping, corner protection, steel straps, and pallets or skids where required. Appearance-controlled material may need additional protection between the product surface and the outer packaging.

Handling and Storage

Use clean, suitable lifting equipment and avoid dragging sheets or striking coil edges. After arrival, store the material indoors in a dry, clean, and ventilated area. Water trapped between adjacent surfaces can cause wet-storage staining. Open or dry any package affected by water as soon as practical and follow appropriate material-handling procedures.

When the product will be used for roofing or cladding, protect it from cement dust, copper contamination, corrosive chemicals, and contact with incompatible materials. Remove metal filings after cutting or drilling because rusting debris can stain the finished surface.

Frequently Asked Questions

What is the difference between Galvalume and galvanized steel?+

Galvalume uses an aluminum-zinc alloy coating, while galvanized steel uses a zinc coating. Galvalume is often selected for atmospheric corrosion resistance, roofing, and heat reflectivity. Galvanized steel is widely valued for forming versatility and sacrificial protection. The correct choice depends on environment, forming, cut edges, paint system, appearance, and budget.

What does AZ150 mean?+

AZ150 commonly refers to a total aluminum-zinc alloy coating mass of 150 g/m2 on both sides, under the relevant standard and test method. Always state the governing standard because coating notation and requirements can vary.

Is Galvalume steel suitable for coastal areas?+

It may be used in some coastal applications, but salt exposure, distance from the shoreline, prevailing wind, roof geometry, coating mass, cut edges, fasteners, sealants, and maintenance must be evaluated. Provide the project location before material selection.

Can Galvalume steel be painted?+

Yes. Galvalume is commonly used as a prepainted steel substrate. Surface pretreatment, primer, topcoat, curing, and forming must be compatible. A trial or approved sample is recommended when adhesion and appearance are critical.

Can Galvalume steel be welded?+

It can be welded using suitable procedures, ventilation, and safety controls. Heat can damage the coating near the joint, and the welded area may require cleaning and post-weld corrosion protection.

Why are cut edges important?+

Cut edges expose the steel substrate. Their performance depends on coating, material thickness, drainage, exposure, and fabrication. Severe environments may require edge protection, suitable detailing, or an alternative coating system.

Can custom widths and sheet lengths be supplied?+

Slitting and cut-to-length processing may be arranged within equipment and material limits. Specify width and length tolerances, edge condition, burr requirement, quantity, and packing method.

What information is needed for a quotation?+

Provide the standard, grade, thickness, width, sheet length or coil form, AZ coating designation, surface treatment, edge, coil weight, quantity, processing, documents, packaging, and destination port.

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