Mechanical Galvanizing (Mechanical Plating)
Mechanically deposited zinc coating for fasteners per ASTM B695 — zinc dust cold-welded by glass bead impact in a tumbling barrel, with no electrolysis and no hydrogen-embrittlement risk, at 5–75 µm thickness.
Last updated: 2026-11
Specifications
Mechanical galvanizing (also called mechanical plating or peen plating) deposits zinc without any electrochemical reaction: fasteners tumble in a rotating barrel with water, chemical promoters, glass bead impact media, and zinc dust, and the tumbling action cold-welds the metal particles onto the surface. Because there is no electrolytic reaction, no acid pickling, and no high-temperature exposure, the process is inherently free from hydrogen-embrittlement risk — and the slightly porous coating actually lets residual hydrogen from prior operations escape. That makes it the corrosion finish of choice for high-strength and spring steels that cannot be safely electroplated, alongside zinc flake. The trade-offs are a matte, slightly rough appearance, barrel-geometry limits, and a per-piece cost above barrel zinc electroplating for high-volume work.
| Process | Mechanical plating (peen plating) — zinc dust cold-welded onto the surface by glass bead impact in a rotating barrel, at ambient temperature |
|---|---|
| Reference standards | ASTM B695 (coatings of zinc mechanically deposited on iron and steel); ISO 12683 (mechanically deposited zinc coatings) |
| Typical coating thickness | 5–75 µm, controlled by the quantity of metal powder and the tumbling time |
| Hydrogen embrittlement | None from the coating process — no electrolytic reaction, no acid pickling (parts are cleaned by alkaline degreasing and glass bead peening in the same barrel), no high-temperature exposure; the slightly porous coating benefits residual hydrogen escape from prior operations |
| Appearance | Matte, slightly rough — not suitable where bright decorative finishes are required |
| Thread fit | Thread dimensional control requires careful process management to avoid excessive build-up |
| Geometry limits | Not all fastener geometries suit barrel tumbling — very long, slender parts may tangle |
| Compared with hot-dip galvanizing | Cold tumbling process with cleaner threads and easier installation, at slightly lower corrosion resistance |
| Relative cost | Per-piece cost typically higher than barrel zinc electroplating for high-volume applications (reported comparison) |
Materials
- High-strength steel fasteners where electroplating hydrogen risk is unwelcome
- Spring steels and case-hardened parts
- Carbon steel fasteners for outdoor service
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (Mechanical Galvanizing (Mechanical Plating)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is per batch, carried with the fastener order. Finishing run adds 5–10 days to the fastener lead time. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When is mechanical galvanizing the right choice over zinc electroplate or hot-dip galvanizing?
When the part is too hard to plate safely or the threads matter too much to hot-dip. Because the process involves no electrolysis and no acid, hardened high-strength and spring parts carry no embrittlement risk and need no post-plate bake; and compared with hot-dip galvanizing, the cold process leaves cleaner threads that mate without oversize tapping, at somewhat lower corrosion resistance. The matte finish and barrel-size limits are the boundaries — bright decorative work and very long slender parts belong on other lines.
What is the MOQ and lead time for this finish?
Finishing runs per batch carried with the fastener order and adds 5–10 days to the fastener lead time. Coated parts follow the finish line that processes them, so confirm the exact schedule against quantity and finish class at quotation.
What should an RFQ for this finish state?
State the base fastener (grade, diameter, length), the coating standard and class (or the process plus thickness/color requirement where no standard callout exists), any salt-spray or friction requirement, and quantity per size — plus destination country and required documents such as a mill test certificate.
Related knowledge
- Reading a Fastener Coating Callout: ISO 10683 Designations, Salt-Spray Hours and What to Confirm With the Plater
- Zinc-Plated vs Hot-Dip Galvanized Fasteners: Which Coating for Which Environment
- Zinc-Flake Coating for Fasteners: When the Evidence Supports It, and What to Verify at the Coater
- Zinc-Flake vs Zinc-Nickel for High-Strength Fasteners: What the Evidence Settles on Hydrogen, Salt Spray, Friction and Specs
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support