Galvanized layer thickness standards for galvanized sheet metal

The standards for galvanized layer thickness in galvanized sheets are established to ensure that the workpiece meets varying thickness requirements after galvanization. The required thickness of the galvanized layer depends on the thickness of the workpiece, with different standards for average and local thickness measurements.

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Galvanized Layer Thickness Requirements

For workpieces with a thickness ≥ 6 mm:

Average galvanized layer thickness: ≥ 85 microns

Local thickness: ≥ 70 microns

This ensures that workpieces of 6 mm or more meet or exceed these specifications.

For workpieces with a thickness between 3 mm and 6 mm:

Average galvanized layer thickness: ≥ 70 microns

Local thickness: ≥ 55 microns

For workpieces with a thickness between 1.5 mm and 3 mm:

Average galvanized layer thickness: ≥ 55 microns

Local thickness: ≥ 45 microns

It is important to note that these standards do not apply to galvanized layers on centrifugally plated and cast iron parts, as their coating thickness requirements may differ.

Standards and Methods of Galvanization

These galvanized layer thickness standards are formulated under GB/T 13912-2002, ensuring that galvanized workpieces meet practical application requirements. The layer thickness must be adjusted based on the workpiece thickness to provide adequate protection.

Galvanization methods include:

Hot-Dip Galvanizing

Produces a thick zinc layer (60-300 g/m²)

Provides strong corrosion resistance

Commonly used for applications requiring high durability

Electro-Galvanizing

Produces a thinner zinc layer (10-50 g/m²)

Offers lightweight protection

Suitable for parts that are painted or require lower corrosion resistance

ASTM A123 Standard for Hot-Dip Galvanized Steel Grating

The ASTM A123 standard outlines clear requirements for the hot-dip galvanization of steel grating:

For steel grating with flat steel thickness of 1.5 mm - 3.0 mm:

Average zinc layer thickness: ≥ 55 microns

Local thickness: ≥ 45 microns

Zinc coating weight: 355g - 390g

For steel grating with flat steel thickness of 3.0 mm - 6.0 mm:

Average zinc layer thickness: ≥ 70 microns

Local thickness: ≥ 55 microns

Zinc coating weight: 460g - 530g

For steel grating with flat steel thickness ≥ 6.0 mm:

Average zinc layer thickness: ≥ 85 microns

Local thickness: ≥ 75 microns

Zinc coating weight: ≥ 600g

These standards serve as clear guidelines for achieving optimal protection in the hot-dip galvanizing process for steel grating.

Summary of Hot-Dip Galvanized Steel Grating Thickness Standards

For thickness ≥ 6 mm:

Average thickness: ≥ 85 microns

Local thickness: ≥ 70 microns

For thickness between 3 mm and 6 mm:

Average thickness: ≥ 70 microns

Local thickness: ≥ 55 microns

For thickness between 1.5 mm and 3 mm:

Average thickness: ≥ 55 microns

Local thickness: ≥ 45 microns

These standards ensure that galvanized steel components meet the necessary protection levels for various industrial applications.