Is there concern about galvanic corrosion when different types of zinc-coated steel are in contact?
There is not a concern of dissimilar metals corrosion (galvanic corrosion) when pairing zinc-coated steel of different types (for example when pairing a hot-dip galvanized bolt with a mechanically galvanized nut). Please be aware, however, that different zinc coatings offer different corrosion protection and service lives. The service life of zinc-coated steel is directly proportional to the thickness of the zinc coating and a thicker zinc coating corresponds to a longer service life. If various types of zinc-coated steels are paired, it is likely the steel with the thinnest zinc coating will be the first to corrode.
For more info on hot-dip galvanized steel in contact with dissimilar metals, refer to AGA guide on dissimilar metals.
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