IS 1573 covers electroplated zinc coatings on steel and iron — the most common corrosion protection for fasteners, brackets, and small steel components. Coating thickness ranges from 5µm (mild indoor) to 25µm (severe outdoor).
Specification for electroplated zinc coatings on iron and steel articles for corrosion protection covering coating thickness, adhesion, and appearance.
Key Values
Fe/Zn 5 (mild indoor)Min 5 µm
Fe/Zn 8 (moderate)Min 8 µm
Fe/Zn 12 (normal outdoor)Min 12 µm
Practical Notes
! Yellow chromate passivation provides better corrosion protection than clear — specify for outdoor use.
! Zinc plating is NOT the same as hot-dip galvanizing (IS 2629) — plating gives 5-25µm, hot-dip gives 45-85µm.
! For structural fasteners exposed to weather, hot-dip galvanizing (IS 1367) is better than zinc plating.
! Hydrogen embrittlement is a risk for hardened steel (>32 HRC) — specify baking after plating.