Galvalume Steel Supplier & Manufacturer in China

Galvalume steel has a coating of 55% aluminum, 43.4% zinc, and 1.6% silicon, while galvanized steel has a 100% zinc coating. Galvalume provides 2-4x better corrosion resistance, higher heat reflectivity (up to 80% solar reflectance vs 30% for galvanized), and a longer service life (25-50 years vs 8-15 years). However, galvanized steel offers better cut-edge sacrificial protection and is 5-15% cheaper. Galvalume is preferred for roofing, coastal environments, and high-temperature applications; galvanized is better for general construction and projects requiring extensive welding.

AZ150 is an ASTM A792 coating weight designation meaning the aluminum-zinc alloy coating weighs 150 grams per square meter (g/m²) total for both sides combined. This is the most commonly specified coating weight for general construction and roofing applications, providing a service life of 25-35 years in moderate environments. For coastal or highly corrosive environments, AZ275 (275 g/m²) is recommended. Lighter coatings like AZ50-AZ70 are used for appliance panels and indoor applications.

Galvalume steel is governed by ASTM A792/A792M (Standard Specification for Steel Sheet, Aluminum-Zinc Alloy-Coated by the Hot-Dip Process). This standard covers coating weight designations (AZ50-AZ275), substrate grades (CS Type A/B/C, FS, SS Grade 33-80, HSLAS), surface treatments, and dimensional tolerances. The equivalent European standard is EN 10346 (grades DX51D+AZ through DX56D+AZ, S220GD+AZ through S550GD+AZ). Japanese standard JIS G 3321 also covers Galvalume (SGCC, SGC340-570).

Galvalume steel service life depends on coating weight and environment: AZ150 in rural/inland environments lasts 30-50+ years; AZ150 in urban environments lasts 25-35 years; AZ150 in coastal/marine environments lasts 15-25 years; AZ275 in coastal environments lasts 30-40+ years. The aluminum component forms a stable oxide barrier that slows corrosion over time, unlike galvanized steel where zinc consumption is linear. Galvalume roofing typically comes with a 25-year perforation warranty from major mills.

Yes, Galvalume steel has excellent paint adhesion due to its surface microstructure and the silicon content in the coating. It is the standard substrate for PPGL (Prepainted Galvalume) coils. For field painting, a primer (wash primer or epoxy) followed by a topcoat (polyester, SMP, or PVDF) is recommended. No weathering period is required before painting, unlike some galvanized products. PVDF-coated Galvalume panels can achieve 30+ year color retention for architectural applications.

The minimum order quantity is 10 tons (approximately 1 standard coil) for standard specifications. Custom thickness, width, coating weight, or surface treatment may require 15-100 tons MOQ. Lead time is 7-15 days for standard sizes from stock, and 20-35 days for production orders. We provide full MTC (Material Test Certificate) per EN 10204 3.1/3.2, SGS or BV third-party inspection, and export-standard seaworthy packaging. FOB Shanghai/Tianjin, CIF, or DDP terms available.

Yes, Galvalume, Aluzinc, and Zincalume are trade names for the same product: hot-dip aluminum-zinc alloy coated steel with 55% Al, 43.4% Zn, and 1.6% Si composition. “Galvalume” is a registered trademark of BIEC International. “Aluzinc” is used in Europe, “Zincalume” in Australia/New Zealand, and “GL” is the generic designation in China and Asia. All conform to ASTM A792 or EN 10346 standards with identical performance characteristics.

Galvalume steel has less sacrificial protection at cut edges compared to galvanized steel because its coating contains only 43.4% zinc (vs 100% in galvanized). In dry or moderate environments, edge rusting is minimal and self-limiting. In coastal or high-humidity environments, exposed cut edges may show red rust within 2-5 years. Mitigation: specify factory-cut edges, apply edge sealant or zinc-rich paint, or use overlap designs. For critical applications, consider Zn-Al-Mg coated steel (ZAM) which combines better edge protection with high corrosion resistance.

Standard surface treatments include:

1) Chromated (most common, provides passivation and temporary corrosion protection during transit);

2) Anti-Fingerprint (AFP) treatment (transparent resin coating, ideal for appliance and visible applications);

3) Oiled (light rust-preventive oil for export shipments);

4) Un-treated (for immediate further processing).

For PPGL substrate, a specially treated surface with enhanced adhesion primer is available. RoHS-compliant Cr-free passivation is available upon request for European market compliance.

As of mid-2026, China FOB prices for Galvalume steel coil range from approximately $700-1,100/ton depending on specification: AZ100 standard grade (DX51D+AZ) around $700-800/ton; AZ150 around $750-880/ton; AZ275 coastal grade around $900-1,100/ton; high-strength S550GD+AZ solar grade around $950-1,150/ton. Prices fluctuate with aluminum/zinc LME prices, HRC substrate costs, and freight rates. Contact Huaxiao Metal for current pricing and volume discounts.