High-density/small-hole perforation: Screens with dense small holes have a larger surface area (including the inner walls of the holes) exposed to the air. In the initial rusting stage, the air circulation and moisture contact degree of the hole inner walls are different from the flat surface, which may lead to uneven rust formation on the hole edges and inner walls. However, as time goes by, the protective rust layer will gradually cover the entire surface, and the overall corrosion resistance will tend to be stable.
Low-density/large-hole perforation: Screens with sparse large holes have a relatively small additional surface area from perforations. The rust layer on the hole edges is easier to form uniformly, and the impact on overall rust resistance is minimal. The main corrosion risk is concentrated on the cutting edges of the holes (if not properly treated).
The perforation process will form sharp cutting edges on the steel plate, and the metal structure at these edges may be slightly damaged, resulting in a higher initial corrosion rate than the flat surface. If the edges are not polished or passivated after perforation, burrs and micro-cracks will easily accumulate moisture and dust, leading to localized pitting corrosion in the early stage of use.
In contrast, if the perforation edges are treated with deburring, rounding, or anti-rust sealing, the local corrosion risk can be significantly reduced, and the rust layer can form uniformly at the edges.
Reasonable layout (e.g., staggered holes with large spacing): It can improve air circulation on both sides of the screen and facilitate the discharge of accumulated water, avoiding long-term moisture retention on the surface, which is conducive to the formation of a dense protective rust layer and enhances overall rust resistance.
Unreasonable layout (e.g., dense holes with poor ventilation): It may cause local moisture accumulation between holes, especially in humid environments, which will slow down the formation of the protective rust layer and even lead to uneven corrosion in some areas.
Edge treatment: Polish and passivate the perforation edges after processing to remove burrs and micro-defects, reducing initial corrosion points.
Pre-rusting treatment: Conduct artificial pre-rusting on the entire screen before installation, so that a uniform protective rust layer is formed on both the flat surface and the perforation edges in advance.
Surface sealing: Spray a layer of transparent protective glaze on the surface (after the rust layer is stabilized) to lock the rust layer, especially to protect the perforation edges from external corrosive media.
