Galvanized Iron / Steel (GI)

Galvanization is the application of a protective zinc coating over steel or iron to prevent rust. In GI steel, the zinc layer shields the base metal in two ways: it provides a physical barrier and offers sacrificial (cathodic) protection by corroding before the steel does.

The most common production method is Hot-Dip Galvanizing (HDG). The steel is thoroughly cleaned and submerged into molten zinc at approximately 450°C. During dipping, the coating metallurgically bonds with the steel — creating strong zinc-iron alloy layers beneath a pure zinc topcoat.

As GI steel ages, the outer zinc slowly transforms into zinc carbonate, forming a stable, self-protecting patina that significantly extends the product’s lifespan in outdoor environments.

Even if the coating is scratched, adjacent zinc continues to corrode preferentially, protecting exposed steel surfaces. This unique self-healing ability is what makes GI a trusted solution in the construction and infrastructure sectors.

Like all coatings, performance depends on coating thickness and environment — high temperatures or aggressive chemicals may require careful specification and maintenance.

Common uses include roofing sheets, wall claddings, roll-formed channels, fencing structures, cable trays, guardrails and a wide range of utilities and accessories.

ZAM Steel (Zn-Al-Mg Coated Steel)

ZAM is an advanced metallic coating combining zinc, aluminum, and magnesium. It is engineered as a next-generation evolution of traditional galvanization, delivering superior corrosion resistance and longer coating life. In the coating, zinc supplies sacrificial protection, aluminum builds a durable physical barrier, and magnesium promotes stable corrosion products that slow degradation.

Typical commercial ZAM compositions are roughly 90–93% Zn, 5–8% Al, and 1–3% Mg. Even small percentages of magnesium noticeably improve performance in chloride-rich or coastal environments by forming protective magnesium-based corrosion films at damaged spots.

ZAM is applied by a continuous hot-dip process similar to HDG, but with a Zn-Al-Mg bath and precise air-knife control. The result is a tough, self-healing coating that often outperforms GI and Aluzinc in long-term exposure tests.

Recommended uses include coastal roofing, architectural cladding, solar module frames, cable trays, agricultural structures, and outdoor fixtures where long life and low maintenance are priorities.

Limitations: ZAM requires attention to welding procedures (due to Mg), and performance can be reduced in very alkaline chemistries — specs should be checked with the mill for specialised applications.