Aluminum-Zinc Alloy Coated Steel Sheet[2]

Updated: 2026-09-25

Overview

Aluminum-Zinc Alloy Coated Steel Sheet, commonly known as Galvalume, is a premium coated steel product developed for superior corrosion protection. The unique coating composition (55% aluminum, 43.4% zinc, and 1.6% silicon) combines the barrier protection of aluminum with the sacrificial protection of zinc. This material was first commercialized in the 1970s and has become a standard in industries requiring long-term durability against environmental exposure. The manufacturing process involves continuous hot-dip coating of cold-rolled steel sheets. The silicon addition improves coating adhesion during forming operations. Compared to traditional galvanized steel, this alloy coating provides 2-4 times longer lifespan in most environments, particularly in coastal or industrial areas with high corrosion potential.

Physical and Chemical Properties

The aluminum-zinc alloy coating creates a metallurgical bond with the steel substrate, resulting in a material with unique characteristics. The coating's heat reflectivity (about 80% of solar radiation) makes it particularly valuable for roofing applications in warm climates. The material maintains good formability, allowing for bending and shaping without coating damage. Chemically, the coating provides excellent resistance to atmospheric corrosion, especially against salt spray and industrial pollutants. The aluminum component forms a stable oxide layer that acts as a barrier, while the zinc offers cathodic protection at cut edges or scratches. The alloy coating is more resistant to high temperatures than pure zinc coatings, withstanding temperatures up to 315°C without significant degradation.

Main Applications

In construction, this material dominates the roofing and siding markets for commercial and industrial buildings. Its combination of durability and aesthetic appeal (available in various colors through paint systems) makes it ideal for architectural applications. The automotive industry uses it for underbody components and exhaust systems where corrosion resistance is critical. HVAC manufacturers value the material for ductwork and heat exchangers due to its heat reflectivity and corrosion resistance. Appliance manufacturers utilize it for oven exteriors, refrigerator cabinets, and washing machine drums. The agricultural sector employs it for grain bins and livestock building panels where long-term protection against corrosive environments is essential.

Safety and Storage

While the material itself poses minimal health risks, proper handling procedures should be followed to prevent injuries from sharp edges. Cutting and forming operations may generate dust or fumes that require local exhaust ventilation. The coated sheets are non-flammable and do not emit toxic fumes under normal conditions. For storage, sheets should be kept in a dry environment to prevent white rust formation (a zinc corrosion product). Stacking should be done on level surfaces with proper support to prevent deformation. When stored outdoors, cover with waterproof materials and ensure adequate airflow to prevent condensation. The material should be kept away from strong acids, alkalis, and salts that could compromise the coating integrity.

B2B Procurement Guide

Industrial buyers should specify several key parameters when procuring Aluminum-Zinc Alloy Coated Steel Sheet. The coating weight (typically expressed as total g/m² or per side) directly affects corrosion resistance - common grades range from AZ50 to AZ150. Sheet thickness tolerance (usually ±0.02mm for precision applications) and width/length dimensions must be clearly defined. Surface treatment options include bare (mill finish), painted, or laminated versions. For painted products, specify the paint system (polyester, siliconized polyester, PVDF) and color requirements. Lead times can vary from stock availability (2-4 weeks) to custom production (8-12 weeks). Quality certifications to request include ASTM A792, EN 10346, or JIS G3321, depending on regional standards. Large-volume buyers (over 20 metric tons) typically receive 5-15% price discounts.