Does galvanized steel truly prevent rust? How to achieve reliable "secondary rust prevention"?

1) Will galvanized steel rust? The answer is: Yes, but much slower.

The core protection of galvanized steel comes from the zinc layer:

Barrier protection: The zinc layer separates the steel from water/oxygen, slowing down corrosion.

Cathode (sacrificial anode) protection: Even with minor damage to the coating, zinc will be preferentially corroded, thus "shielding" the steel.

Therefore, it is not "never rust-proof," but rather "more rust-resistant and more corrosion-resistant," especially performing well in ordinary outdoor environments.

2) Which areas are most prone to rusting first? (This is also where you should do rust proofing) Based on experience and industry consensus, the first problems with galvanized steel are often not on the main surfaces, but rather in these areas that "damage the zinc layer":
* Cut edges/drilled edges: The zinc layer is cut off, exposing the steel base.
* Welded areas: High temperatures can burn off the galvanized layer.
* Deep scratches/bumps exposing the iron: Sacrificial protection is weakened, requiring remediation (touch-up coating/zinc replenishment/painting).
* Water accumulation, salt spray, chemical corrosion environments (near the sea, swimming pools, chemical industrial zones).
* Contact with dissimilar metals (increased risk of electrochemical corrosion).

3) The best approach to matching the search intent of "rust proofing galvanized steel": Choose a solution based on the scenario.
* Scenario A: Ordinary indoor/dry environment (Most people don't actually need additional rust prevention).
* For shelves, indoor supports, dry warehouse components:
* The key is to keep them clean and dry, avoiding prolonged dampness and water accumulation.

Scenario B: Outdoor rain exposure, but not extreme (Recommendation: Focus on repairing "end faces/damage points")
You don't need to repaint the entire part; usually, this is more cost-effective:
Clean: Remove oil, dust, and white rust (white rust is a corrosion product of zinc).
Treat exposed iron points: Sand down to a solid base.
Apply zinc/zinc-rich primer: Prioritize zinc-rich primer systems (better matched to galvanizing logic).
Seal with topcoat if necessary: ​​Improve weather resistance and aesthetics.