Z275 is a hot-dip galvanized coating designation where the number 275 indicates a double-sided zinc coating weight of 275 grams per square metre (g/m²). This corresponds to a nominal single-side zinc thickness of approximately 20 micrometres (µm). Z275 is one of the heaviest and most corrosion-resistant standard zinc coatings available for continuous galvanizing, typically used in harsh outdoor environments.

The coating is applied by immersing cold-rolled steel coil in a molten zinc bath at about 450°C, forming a metallurgically bonded zinc-iron alloy layer. The thick zinc provides both a physical barrier and sacrificial protection: even if the coating is scratched, the zinc corrodes first, protecting the underlying steel.

Z275 offers excellent corrosion resistance. Under standard salt spray testing, it typically exceeds 1,500 hours before red rust appears, compared to around 500-800 hours for Z120. It is suitable for coastal areas, industrial atmospheres, and applications requiring long service life (often 20-30 years or more with minimal maintenance).

Typical applications include:

● Construction: roofing, wall cladding, gutters, downspouts, structural purlins for industrial buildings

● Infrastructure: highway guardrails, utility poles, transmission towers, road signs

● Agriculture: grain silos, livestock equipment, ventilation systems

● Automotive: underbody parts, chassis components

● General industry: storage tanks, heavy-duty cable trays, electrical enclosures