Galvanized steel：Everything you need to know
Time : 2023-09-15
Galvanized steel has a zinc coating that helps prevent corrosion. It is one of several metal coatings that can be applied to steel to help combat corrosive elements. This protection is critical for steel used in applications such as automotive parts, appliances, construction materials and HVAC.
The galvanizing process involves the continuous hot-dip application of a durable protective coating of zinc. This zinc coating helps prevent corrosive materials from reaching the steel underneath.
But not all steel has the same coating rate. Each steel plate product has its own weight designation system, defined by ASTM standards. For example, A653/A653M is a standard for metal-coated sheets commonly used for hot-dip galvanized products.
Galvanized steel is available in a variety of base metal grades and coating weights. Coating designations (such as G-60 and G-90) refer to the total coating amount per square foot on both sides.
Let's break it down in detail: G-90, which is the most common coating, is equal to 0.9 ounces; G-60 is 0.6 ounces, etc. The higher the coating weight, the more corrosion-resistant the steel is.
While zinc's protective layer does block corrosive substances, over time the protective layer may fade, which may cause your steel to rust.
However, this usually only occurs under extreme conditions. This means it is important to understand the environmental conditions of your application. For example, materials with high relative humidity or metals exposed to constant moisture are not ideal.
Galvanized sheets can be welded and soldered. Additionally, galvanized steel can be formed without peeling or spalling, and operations such as stamping, cold drawing, double seaming, and brake or roll forming will not compromise its protective properties.
Generally speaking, most galvanized steel products can be painted if properly prepared.
All steel contains iron, which means steel is a ferrous metal. In fact, steel is about 98% iron – it’s the rest of the metal’s composition that really determines the uses it’s best suited for. Galvanized steel is considered a ferrous metal.
Generally speaking, the cost of galvanized steel will be higher than standard steel due to the added process. The heavier the coating, the higher the cost.
Galvanizing contains 9-12% lump iron and aluminum. The sheets are heat treated after coating to create a zinc-iron alloy and eliminate splatter.
Galvanized sheet can be painted without further surface preparation other than normal cleaning, and can be bent and simply shaped without compromising its paintability or corrosion resistance. Typical coating weights are A60 or A40.
Typical applications for galvanized annealing include signs, metal doors and partitions, truck and trailer bodies, heater and furnace components, and more.
RoHS (Removal of Hazardous Substances) is an EU directive standard aimed at preventing risks to human health and the environment associated with the management of electrical and electronic waste.
RoHS applies to metals, including galvanized steel, related to hazardous substances used in the surface treatment of coated panels. These harmful substances include mercury. Lead, cadmium, polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE), and hexavalent chromium are commonly used as chemical treatment options for galvanized products.
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