Galvanized Iron (GI) steel

Specification Parameters

Parameters of Galvanized Steel (GI Steel)
Parameter Category	Specific Parameter	Typical Value / Description	Importance / Effect
Base Steel Properties	Steel Grade/Type	Commercial Quality (CQ), Forming Quality (FQ), Structural Quality (SQ), HSLA	Determines the mechanical properties (strength, formability) for the intended application (e.g., ductility for deep drawing, strength for structural parts).
	Yield & Tensile Strength	Varies widely by base steel grade (e.g., 250 MPa - 550 MPa+ YS)	Provides the structural integrity and strength of the part. The galvanizing process does not significantly alter these properties.
	Surface Condition	Clean, smooth, free of scale, oil, and oxides	Critical for ensuring a uniform, adherent zinc coating. Often requires pre-treatment (pickling).
Zinc Coating Properties	Coating Mass/Weight	Mass: 50 to 600 g/m² (total both sides)	The primary measure of corrosion protection. A higher coating mass (weight) indicates a thicker zinc layer and longer service life.
		Common Designation: G60 (183 g/m²), G90 (275 g/m²)
	Coating Thickness	~5 µm to ~80 µm (per side)	Directly related to coating mass. Often measured with magnetic or electromagnetic gauges.
	Coating Structure	Layers of Zinc-Iron intermetallic alloys topped with pure zinc	The galvanizing reaction creates a metallurgical bond that is integral to the steel surface, making it highly durable and abrasion-resistant.
	Spangle Size	Regular spangle, minimized spangle, or spangle-free	An aesthetic parameter. Minimized or zero spangle is often preferred for painting.
Testing & Performance	Adherence/Bend Test	Bent around a mandrel 180° without flaking off (e.g., ASTM A 525)	Tests the ductility and adhesion of the coating. It must not crack or peel away from the steel substrate during forming.
	Uniformity Test	Preece Test (CuSO₄ dip): Withstands a specified number of 1-minute dips without copper deposition.	A quick test to check that the coating is continuous and free of bare spots.
	Corrosion Resistance	Salt Spray Test (ASTM B117): Hours to white rust (zoxide) and red rust (steel).	Provides a comparative measure of corrosion performance. A G90 coating typically provides ~30 years in rural atmospheres.
Process Standards	Governing Standards	ASTM A653/A653M (Sheet Steel)	These standards specify the requirements for coating mass, adherence, and base metal properties.
		ASTM A123/A123M (Structural/Plate)
		ASTM A153/A153M (Hardware)

Product Description

Galvanized Iron (GI) steel plays a vital role in everyday life by delivering strength, durability, and corrosion resistance across a wide range of applications exposed to moisture or harsh environmental conditions. As a foundational material in fields like construction and manufacturing, it ensures long-lasting performance and structural reliability—making it essential for products and infrastructure where rust prevention and extended service life are critical.

Shanghai Ruichao Industrial supplies a wide selection of high-quality GI (galvanized iron) steel products—including sheets, coils, and plates—sourced directly from leading Chinese mills. Each item in our inventory undergoes strict quality inspections by our expert team, ensuring reliable performance and detailed product specifications. We help you choose the right GI steel that meets your exact needs, offering cost-efficient solutions without compromising on quality or service. Trust Ruichao for straightforward access to durable, corrosion-resistant steel tailored to your applications.