Capability
Zinc Plating
Zinc is the most widely specified, most cost-effective protective plating for steel components. It works in two ways at once: as a barrier coating that physically separates the steel from the operating environment, and as a sacrificial coating that corrodes preferentially to the steel underneath, protecting the part even after the plating itself is breached.
Modern zinc plating, combined with a trivalent chromium passivate and an appropriate topcoat, routinely delivers 750 to 1,000+ hours of ASTM B117 salt-spray performance — well beyond the 240 to 360 hour performance of earlier generations, and now the baseline expectation for under-vehicle and outdoor-exposed hardware across automotive, agricultural, and industrial supply chains.
Salt-Spray Performance
750–1,000+ hrs
Typical Thickness
5–25 µm
Substrates
Steel & Iron
Processing
Rack & Barrel
Where Zinc Plating Fits
Common Applications
Zinc plating is the workhorse finish across most of the parts CMC processes. It performs especially well on tubular components, complex stampings, and parts that need post-form processing without compromising the coating.
Typical applications include:
- Brake fittings, cooling pipes, transmission fittings — tubular components where corrosion protection and consistent thread engagement matter
- Fasteners — high-volume bolts, nuts, washers, and clips processed through barrel
- Stampings and brackets — chassis hardware, mounting brackets, and structural fasteners
- Hydraulic and pneumatic line components — fittings, brackets, and clips
- Appliance and HVAC hardware — interior structural and mounting hardware
Color & Performance
Passivate and Topcoat Options
After plating, zinc parts receive a passivate layer that boosts corrosion resistance and gives the part its final color. CMC runs all three common passivate variants — clear (blue-silver), black, and yellow (iridescent) — all in trivalent chromium chemistry, fully hexavalent-chromium-free, and meeting RoHS, REACH, and end-of-life vehicle directives.
For severe-duty applications, an additional topcoat/seal can be applied over the passivate. This adds a final corrosion-resistant layer and is the difference between hardware that meets a 480-hour salt-spray spec and hardware that meets a 1,000+ hour spec.
Production Capabilities
Rack and Barrel at Scale
Across our four facilities and 17 processing lines, zinc plating runs in both rack and barrel processing methods. Rack handles larger parts and parts that can't tumble; barrel handles the high-volume hardware where throughput and cost-per-part are the constraints.
Every line is fully automated. Chemical feed systems on most process tanks are automated as well, which removes a layer of human variation and gives our customers the consistency they expect on every order. Hydrogen embrittlement relief baking is available in-house for high-strength steel fasteners, scheduled within the time windows ASTM F1940 and major OEM specifications require.
Specifications & Standards
Standards We Can Meet
ASTM B633
Standard specification for electrodeposited coatings of zinc on iron and steel
ASTM F1941
Specification for electrodeposited coatings on threaded fasteners
ASTM B117
Salt-spray testing standard, 750 to 1,000+ hr performance routinely achieved
ASTM F1940
Hydrogen embrittlement relief baking protocol, performed in-house
IATF 16949
Automotive quality management process control across all facilities
RoHS, REACH, ELV
Trivalent chromium passivation, fully hexavalent-chromium-free
Specifying zinc for a part?
Send us a drawing, a specification, or a part description. We’ll match the right zinc chemistry, the right passivate, and the right processing method to your geometry, your operating environment, and the standard your program runs to.