Difference Between Galvanized and Galvalume Steel
Galvanized steel and galvalume steel are widely used in our daily life for roofs and wall panels, etc. Both have strong corrosion resistance and smooth and shiny surface. So what’s the difference between them and which one is better for your projects?
- Coating: The main difference between galvalume and galvanized steel is the protective coating. Galvanized steel is coated with pure zinc coating. While galvalume has a Al-Zn coating, that is 55% aluminium, 43.4% zinc, and 1.6% silicone. The aluminium in the galvalume coating helps to better protect the panels against corrosion in certain environments.
- Appearance: Galvalume steel is generally considered to have a better appearance when compared to galvanized steel. The two coatings’ differences are subtle, but galvalume offers a smoother appearance with 'spangles', and its base colour is silver-white. A galvanized coating is more rough.
- Corrosion resistance: Based on their substrates, the special coating structure of galvalume makes it more resistant to corrosion than galvanized. Generally, the corrosion resistance of galvalume steel is 6 to 8 times that of galvanized steel, especially in acid rain. It can guarantee no rust for 20 years.
- Atmospheric corrosion resistance: In the harsh marine environment, rural and industrial environment, the corrosion resistance of galvalume steel is better than that of galvanized steel.
- Adaptability to humidity: the Cleveland condensation experiment shows that the humidity and corrosion resistance of galvalume steel sheet is 5-6 times better than that of galvanized steel sheet.
- Heat resistance: The heat resistance of galvalume steel is better than that of galvanized steel. The galvalume steel sheet can withstand a temperature of 677 , and often works at 315 without discolouration.
- Generally, cold galvanized steel can last 5-10 years and hot-dipped galvanized steel sheet has a lifespan of 20-30 years, mainly depending on the zinc layer thickness. The base steel will be damaged as the zinc layer is all corroded. But due to aluminium’s excellent prevention of corrosion, the galvalume steel has a lifespan about twice that of traditional galvanized steel.
- Applications: Galvalume is ideal for humid and hot environments, commercial buildings, residential homes, storage units, and more. Galvanized metal is better suited to dry climates free of major air pollution or pooling water. The aluminum in galvalume will corrode with exposure to alkalines, which can cause the metal to degrade and lose its strength.
- Price: Due to better performance and fewer qualified manufacturers, galvalume steel price has a higher than that of galvanized metal.
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