Glass Curtain Walls: The Preferred Alternative to Aluminum Alloy — A Galvannealed Steel (GA) Curtain Wall Solution for Breakthroughs in Safety and Economics

Material Selection: Galvannealed Steel (GA)

Solution Highlights：

Advanced Fire Safety：Early glass curtain walls primarily used aluminum alloy (6063-T5) as the mainstream material due to its light weight and good weather resistance. However, as high-rise buildings impose increasingly stringent requirements on fire safety, structural strength, and life-cycle cost, aluminum alloy has shown clear limitations: a melting point of ≤660℃, susceptibility to softening and collapse in fire, and relatively low tensile strength, making it difficult to meet wind-pressure resistance requirements for large spans. Galvannealed Steel (GA), as a non-combustible material, delivers a fundamental improvement in fire safety. Its steel substrate has a melting point of >1,400℃ and a tensile strength of 350-980MPa, which is 2-6 times that of aluminum alloy (160-265MPa), providing a multiplied advantage in structural strength.

Breakthroughs in Welding and Coating：Aluminum alloy is difficult to weld and requires anodizing before coating, resulting in complex processes. In contrast, the matte Galvannealed coating provides a physical anchoring effect, achieving excellent coating adhesion without anodizing or pre-treatment. It also offers superior dissimilar welding performance, with a peak dissimilar welding force of 2,349N, overcoming the welding challenges of aluminum materials.

Life-Cycle Economics and Environmental Performance：Galvannealed Steel (GA) has a low initial cost, with material procurement cost at approximately one-fifth that of aluminum alloy, saving over 50% and delivering significant life-cycle cost advantages. Steel is easily recyclable through magnetic separation, and chrome-free products comply with RoHS standards, supporting green building certification.

Recommended Applications：

Curtain wall mullions and transoms: GA offers the most prominent high-strength advantage  (350-980MPa), enabling reduced-thickness design；

Backing plates and closure panels: Utilizing GA’s corrosion resistance (salt spray >150h, 5% red rust) and coating adhesion advantage (Rating 5)；

Fire-rated curtain wall systems: GA’s non-combustible properties and high-temperature resistance (>300℃) meet high fire-rating requirements；

Door and window frames: Requires a thermal break design to fully leverage the strength advantage；

Exterior decorative components: Requires spray coating, with appearance meeting design requirements.

Galvannealed Steel (GA) is a safer, more economical, more environmentally friendly, and higher-performance alternative for curtain wall applications.