Damage and failure of the anti-corrosion coating on guardrails in cities
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This is a guardrail from a southern city; it’s likely coated with plastic, and after 1 to 2 years it ends up looking like this. The main reason is that the coating process and the coating materials have defects; the railings are exposed to the air for long periods of time and are subject to rainwater exposure. When selecting materials, considerations should be given to corrosion resistance, oxidation resistance, protection against ultraviolet rays, wear resistance, as well as resistance to penetration and freeze-thaw cycles. The substrate must be treated by sandblasting to remove rust, achieving an SA2.5 standard – lower levels of surface treatment such as acid washing or grinding are not sufficient.
The damage to the powder-coating layer of guardrails in southern cities is mainly due to defects in the powder-coating process and materials. Prolonged exposure to the external environment and rainwater erosion leads to the failure of the anti-corrosion layer. When selecting materials, attention should be paid to their corrosion resistance, oxidation resistance, UV resistance, wear resistance, and impermeability. At the same time, sandblasting should be used for surface preparation to remove rust, achieving the SA2.5 standard; inefficient surface treatment methods such as pickling or grinding should be avoided. .
Inadequate pre-treatment of the steel pipes, coupled with substandard coating materials and non-standard coating processes, have led to severe rusting.