Mechanical zinc plating and galvanizing

Also called mechanical galvanizing. Parts, glass beads, zinc dust and a chemical promoter tumble together in a rotating open-ended oblique barrel. Impact energy transferred through the glass beads cold-welds the fine metal particles onto the substrate and builds a uniform coating. No electrolytic current is involved, so the deposition itself introduces no hydrogen into the steel. ASTM B695 X3.1 supports that position. It does not make a part immune: acidic cleaning or pickling ahead of the process can still charge hydrogen, so MFI controls the cleaning route as carefully as the deposition route.

What you get

• No electrolytic hydrogen from the deposition, which is why it suits high-strength fasteners above about Rockwell C40
• Uniform coverage across threads, recesses and complex geometry
• Zinc, tin, or other ductile metals and mixtures of ductile metals
• A slightly porous matte finish that accepts supplementary coatings