Thickness of anti-corrosion layer on cable tray surface

The anti-corrosion layer on cable trays typically ranges from 45µm to 55µm for hot-dip galvanizing, depending on the tray thickness and environmental conditions.

Hot-Dip Galvanizing

Hot-dip galvanizing (HDG) is the most common and durable anti-corrosion treatment for steel cable trays, especially in harsh outdoor or industrial environments. The process involves immersing steel components in molten zinc, forming a zinc-iron alloy layer and a pure zinc layer, which provides excellent adhesion and corrosion resistance .

• Local thickness: Minimum 45µm for tray sheets 1.5–3mm thick; heavier components (>3mm) require ≥55µm .
• Mean coating mass: Corresponds to at least 325g/m² for standard trays .
• Service life: Typically ≥40 years in outdoor corrosive environments . The thickness is measured at multiple points using a magnetic thickness gauge to ensure uniform protection . HDG is preferred for coastal, industrial, or outdoor applications due to its superior durability.

Zinc-Rich Coatings and Electro-Galvanizing

For smaller parts or fasteners where HDG may deform thin elements, zinc-rich coatings or electro-galvanizing are used. These processes deposit a thinner, uniform zinc layer:

• Electro-galvanized layer: Thin, bright, and uniform, but offers lower corrosion resistance compared to HDG .
• Zinc-rich coatings: Applied by spraying or centrifuging at lower temperatures (≤280°C), providing moderate protection . These coatings are suitable for indoor or mild outdoor environments, with service life ranging from 12 to 30 years depending on the alloy and environmental exposure .

Other Anti-Corrosion Treatments

• Galvanized nickel: High-cost, suitable for heavy outdoor corrosive conditions, service life ≥30 years .
• Powder electrostatic spraying: Ideal for indoor dry environments, service life ≥12 years .

Summary

The selection of anti-corrosion layer thickness depends on:

1. Tray material and thickness: Thicker trays require thicker coatings.
2. Environmental conditions: Coastal, industrial, or outdoor exposure demands HDG or ZnAl/ZnMg alloys.
3. Expected service life: HDG provides the longest protection, while powder coatings are suitable for indoor use. For design and compliance, it is essential to specify the coating type and thickness in project documents to ensure adequate corrosion protection and longevity .