Galvanized steel coil is a product that forms a zinc protective layer on the surface of steel through the galvanizing process, which is mainly used to prevent rust and extend service life. According to the different galvanizing processes, it is mainly divided into:
Hot-dip galvanizing (GI, Galvanized Iron)
Electro-galvanized (EG, Electro-Galvanized)
Alloy galvanning (GA, Galvannealed)
What is galvanized steel coil used for?
Galvanized steel coil is a rust-proof material that covers the surface of steel with a zinc layer through hot-dip galvanizing or electro-galvanizing processes. It is used in:
Construction industry: used for roof and wall color-coated plate substrates, steel structure frames and guardrails, with strong weather resistance.
Home appliance manufacturing: refrigerator, washing machine shell, etc., galvanized and then sprayed, taking into account both rust prevention and beauty.
Automotive industry: body structural parts, fuel tanks (hot-dip galvanizing) and interior parts (electro-galvanizing), lightweight and corrosion-resistant.
Electronic equipment: computer cases, distribution cabinets, etc., the surface of electro-galvanized sheet is smooth and suitable for precision processing.
Is galvanized better than stainless steel?
Galvanized steel requires high strength or welding processing (such as overall galvanizing of steel structures after welding), and the surface can be sprayed/coated (such as color-coated plates to hide the appearance of the zinc layer). It is suitable for limited budgets and generally corrosive environments. Stainless steel requires sterility and easy cleaning (such as hospitals and food factories), and requires permanent maintenance-free (such as landmark buildings). It is suitable for scenes with humid environments and salt/acid and alkali content.
Will galvanised steel rust?
The rusting of galvanized steel depends on the quality of the zinc layer, the use environment and the maintenance
Under what circumstances will rust occur?
|
Reason |
Phenomenon |
Solution |
|
Zinc layer wear/scratches |
The substrate is exposed and red rust appears locally (such as cutting edges and bolt holes) |
Apply anti-rust paint or zinc-based paint |
|
Zinc layer depletion |
Large areas of white rust (zinc corrosion product) → red rust (steel corrosion), common in long-term outdoor use |
Choose a thick zinc layer (such as Z275) or perform regular maintenance |
|
Highly corrosive environment |
In coastal areas (salt spray) and acid rain, zinc layer corrosion is accelerated |
Switch to galvanized steel (GL) or stainless steel (304/316) |
Comparison of rust resistance of different galvanizing processes
|
Type |
Coating thickness |
Typical life (normal environment) |
Applicable scenarios |
|
Electro-galvanized (EG) |
3-20μm |
5-10 years |
Indoor chassis, electrical housings |
|
Hot-dip galvanized (GI) |
20-200μm |
15-30 years |
Building roofs, steel structures |
|
Galvanized alloy (GA) |
10-50μm |
20 years and above |
Automobile body panels, high-end home appliances |
