Two Kinds of Surface Treatment: Hot-dip Galvanizing & Plastic Coating
Guardrail surface treatment can be divided into: hot dip galvanizing and plastic coating.
Almost all of highway guardrails employ hot-dip galvanizing, which is an effective metal treatment and is a form of galvanization. It is the process of coating iron and steel with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around 840°F (449°C). When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (O2) to form zinc oxide (ZnO), which further reacts with carbon dioxide (CO2) to form zinc carbonate (ZnCO3), a usually dull grey, fairly strong material that protects the steel underneath from further corrosion in many circumstances.
Another surface treatment of guardrail is plastic coating, which is typically applied electrostatically and is then cured under heat to allow it to flow and form a "skin". The powder may be athermoplastic or a thermoset polymer.
Galvanized guardrail beam with good mechanical properties, and can be used in harsh environment.
The surface of plastic coated guardrail beam can be painted different colors, it has elegant appearance.
Features:
Hot-dip galvanizing: anti-corrosion, anti-scratch, anti-oxidation, anti-rust.
Plastic coating: elegant appearance, wear resistance, low cost.
| Model | Average check limit triple-spot test | Min check limit triple-spot test |
|---|---|---|
| Guardrail beam, post, end terminal | 600 g/m2(85 um)
|
425 g/m2 (61 um) |
| Fasteners, offset block, bracket | 350 g/m2(50 um) | 275 g/m2 (39 um) |
| Custom requirements are available. | ||