Why does corrosion matter?
When a fastener rusts, it is not only the fastener that is damaged — the integrity of the assembly is at risk. A rusted rivet or bolt can become impossible to remove, can stain the surrounding material, and can lose its strength.
Zinc-plated steel
A zinc coating is applied over the steel part. Zinc protects the steel against corrosion by “sacrificing itself” — that is, it wears away first. It is an economical and common solution.
- Suitable for indoor and moderate outdoor applications
- Low cost
- If the coating is damaged, protection weakens
Stainless steel
Corrosion resistance is in the material itself — not a coating, but in the structure of the alloy. 304 and 316 are the most common grades; 316 is more resistant to chloride-containing environments (sea, pool).
- Long life, resistant to surface damage
- Suitable for food contact, marine environments, chemical exposure
- More costly than zinc-plated steel
How to decide?
Evaluate the environment: Indoor, dry → zinc-plated steel is sufficient. Outdoor, humid → quality galvanizing or stainless. Sea, chemical, food → 316 stainless. Salt-spray test results (ISO 9227) are used to compare the lifespan of different coatings.
Watch for galvanic corrosion
When different metals contact each other, galvanic corrosion can occur. For example, fitting a stainless rivet to an aluminum panel can cause the aluminum to corrode rapidly in a humid environment. Material selection must be considered not only for the rivet itself but also for the parts it contacts.