I. Core Industry Overview: What Is Galvanized Coil?

Hot-dip galvanized coil (commonly abbreviated as GI coil in the industry) is an anti-corrosion metal coil made from hot-rolled or cold-rolled steel substrates. Through the continuous hot-dip galvanizing process, a uniform zinc coating is formed on the steel surface. It ranks as the most widely used coated steel base material in global industrial applications.

It relies on a dual anti-rust mechanism: barrier protection from the zinc coating and sacrificial anode protection. Even if scratches appear on the sheet surface, the zinc layer will oxidize first to shield the steel substrate, delivering a service life of 10 to 30 years under outdoor exposure.

Three mainstream product categories are available on the market: regular spangled galvanized steel, non-spangled fingerprint-resistant galvanized steel, and zinc-aluminum-magnesium alloy coated steel. Zinc coating weight can be customized from Z40 to Z275, with sheet thickness ranging from 0.12 mm to 6.0 mm. The material supports full-process fabrication including leveling, slitting, stamping, bending and welding. Balancing excellent workability and cost efficiency, it offers far better value for money than anti-corrosion alternatives such as stainless steel sheets.