"Galvanized" is not the same as "stainless steel":

Whether hot-dip galvanizing or electroplating, the corrosion protection principle is cathodic protection using a "sacrificial anode." If the coating is severely scratched, the underlying steel will still rust from the scratched area. In extremely corrosive environments (such as long-term immersion in seawater), stainless steel lead screws should be considered (although this will significantly increase the cost).

Hydrogen embrittlement risk (especially with electroplating):

Hydrogen evolution during the electroplating process can cause hydrogen embrittlement in high-strength steel, resulting in delayed fracture under stress. If you purchase high-strength electroplated galvanized lead screws (e.g., grade 8.8 and above), be sure to confirm with the supplier that they have undergone effective dehydrogenation treatment. This is a significant safety hazard.

Subsequent Processing:

Remember, hot-dip galvanized lead screws are virtually inoperable after galvanizing, as the hard coating can instantly damage cutting tools. All processing must be completed before galvanizing. Electroplated galvanized lead screws can be slightly adjusted.