Many industrial equipment have intact paint surfaces when leaving the factory, but rust and peeling occur shortly after use. Most people mistakenly blame the paint. Combining on-site cases and inspection experience, we share three easily overlooked but key details before painting.

1. Chamfering of Sharp Corners

Rust often occurs on cutting surfaces, right-angle edges and screw holes; sharp corners lead to thin paint film and easy erosion.

Notes: Cut edges and welding sharp corners must be chamfered; bolt and mounting holes should be polished to ensure uniform paint adhesion.

2. Optimize Structural Design to Avoid Coating Blind Areas

Paint failure mostly comes from design flaws; unreasonable structures cause narrow gaps and dead corners, leading to incomplete spraying and corrosion.

Notes: Avoid narrow closed structures in design; arrange processes properly and coat key parts before assembly.

3. Completely Remove the Hardened Layer on the Cutting Surface

Flame/plasma cutting forms a hardened layer (≈0.1–0.2mm, hardness up to 350~450HV), weakening paint adhesion and causing peeling.

Notes: Before painting, completely remove the hardened layer and oxide scale by grinding or enhanced sandblasting to expose qualified metal.

The key to equipment anti-corrosion is early detail control; small omissions shorten service life and increase costs.