Galvanised sheet, formally known as galvanised steel sheet, is manufactured by uniformly coating cold-rolled or hot-rolled steel sheet substrates with a layer of metallic zinc through a specific galvanising process. This creates a metal sheet with outstanding corrosion resistance, typically supplied as individual flat sheets. Its core function lies in the zinc layer's ability to isolate the substrate from air and moisture, while simultaneously leveraging zinc's ‘sacrificial anode effect’ to significantly extend the service life of the steel. It is a commonly used anti-corrosion sheet in both industrial and civil applications.

I. Galvanised sheet and galvanised coil are essentially ‘the same material in different forms’. Their core production processes are identical, differing only in the finishing stage:

Common Pre-Processing Steps: Both sheets and coils undergo:

- Substrate pre-treatment (degreasing → pickling → rinsing → drying)

- Galvanising (hot-dip / electro-galvanising)

- Post-treatment (passivation → oiling)

to ensure uniform, strongly adherent zinc coatings.

Differentiated Finishing Stages:

Galvanised Coil: After galvanisation, the steel strip is directly wound into a ‘coil’ for convenient bulk storage and transportation.

Galvanised Sheet: The galvanised coil undergoes ‘uncoiling processing’ (unwinding, flattening, and cutting to fixed lengths) to form individual flat sheets. These are delivered as ‘sheets’ to meet applications requiring non-continuous processing.

II. The widespread application of galvanised sheets stems from their core advantages of balancing corrosion resistance with processing convenience:

Superior corrosion resistance: The zinc coating physically isolates the substrate from corrosive agents (water, oxygen, salts). Even if the zinc layer is locally damaged, zinc undergoes electrochemical corrosion (acting as a sacrificial anode) to protect the substrate from rusting, significantly extending the steel's lifespan (3-5 times longer than ordinary steel sheets).

Excellent workability: Directly suitable for shearing, stamping, bending, and welding (with superior weldability in certain grades like GA sheets), accommodating diverse product forming requirements without additional anti-corrosion treatments (e.g., painting), thereby streamlining production processes.

High cost-effectiveness: Compared to stainless steel or aluminium alloys, galvanised steel offers lower initial costs and reduced maintenance expenses (eliminating frequent repainting). It represents one of the optimal choices for ‘low-cost + high corrosion resistance’ in moderate to low corrosion environments.

Environmentally sustainable and recyclable: The base material is steel, and the zinc coating contains no harmful substances. Post-use, it is 100% recyclable, meeting environmental standards and ensuring high resource utilisation.