Full definition
A corrosion protection process that applies a zinc (Zn) coating to steel or iron substrates, exploiting zinc's dual protection mechanism: barrier (physical coating) and sacrificial anode (zinc corrodes preferentially to protect exposed steel at cuts or scratches). Two main methods: (1) Hot-dip galvanizing — immersing clean steel in molten zinc bath at 450°C; coating thickness 45-200 μm; per ASTM A123 (structural) and A153 (hardware); life expectancy 25-75+ years depending on environment. (2) Electrogalvanizing — electroplating zinc from solution; thinner coating 5-25 μm; smoother finish; per ASTM B633. Coating weight specified as g/m² or thickness in μm. Testing: magnetic thickness gauge (ASTM B499), adhesion (bend test per ASTM A143). Applications: structural steel, guardrails, conveyor frames, fasteners, roofing, and electrical conduit. Alternative zinc coatings: mechanical plating, sherardizing, and zinc-rich paint. Galvanizing is the most cost-effective long-term corrosion protection for exposed structural steel.