Hot dip galvanizing is a unique process. When clean steel is immersed in molten zinc, a metallurgical reaction between iron and zinc forms a series of zinc-iron alloy layers that provide the strong coating that is an integral part of steel.
The zinc-iron alloy layer formed by hot-dip galvanizing not only forms a barrier between the profile and the environment, but also acts as a cathodic protection for the profile. The cathodic protection provided by zinc means that the galvanized coating sacrifices itself to protect the underlying substrate from corrosion. The sacrificial nature of the coating results in a durable high-quality profile.
For over 100 years, hot-dip galvanized profiles have been widely used for corrosion protection in agricultural, solar, automotive, construction, and industrial environments, including petrochemicals, transportation, and utilities.

1. The initial cost of hot-dip galvanized profiles is lower than most treated steels. In addition, the galvanized steel is ready for use upon delivery.
2. A major advantage of hot-dip galvanized profiles is their durability. Surface coatings provide both physical and cathodic protection, with a high level of corrosion protection, steel structures or components typically reach their design life without maintenance, even when exposed to harsh environments, reducing maintenance budgets.
3. Due to its unique metallurgical combination, the galvanized coating is very tough, so galvanized steel has excellent resistance to mechanical damage during handling, storage, transportation and installation.
4. The metallurgical reaction that takes place between zinc and steel is a diffusion process, which means that the coating increases perpendicular to all surfaces, so the galvanized layer at the corners and edges is at least as thick as the rest of the item. In addition, since hot-dip galvanizing is a full-dip process, the hollow structure is coated on the inside and outside.

1. Clean the steel in a degreasing solution
2. After cleaning, put the steel in a bucket of diluted hot sulfuric acid for pickling
3. Flux the steel in an aqueous solution (usually zinc ammonium chloride)
4. After the flux, the steel is dipped into a molten zinc bath for galvanizing
5. Check the finished product

Hot-dip galvanized standard The technical parameters of hot-dip galvanized coatings on steel products are specified by a single standard, namely BS EN ISO 1461 “Hot-dip galvanized coatings on steel products – Technical parameters and test methods”. When the steel is hot-dip galvanized, the surface is completely covered with a uniform coating, and the thickness of the coating is mainly determined by the thickness of the galvanized steel itself (please refer to the table for details).

Product thickness	Minimum zinc layer thickness		Minimum zinc layer thickness
	g/m2	μm	g/m2	μm
steel products>6mm	505	70	610	85
3mm<steel products≤6mm	395	55	505	70
1.5mm≤steel products≤3mm	325	45	395	55
steel products＜1.5mm	250	35	325	45
steel casting≥6mm	505	70	575	80
steel casting＜6mm	430	60	505	70

Rebar and round steel (textured steel products) Product thickness	Minimum zinc layer thickness		Minimum zinc layer thickness
	g/m2	μm	g/m2	μm
diameter≥20mm	325	45	395	55
6mm<diameter≤20mm	250	35	325	45
diameter≤6mm	145	20	180	25
Other products (including castings)
diameter≥20mm	325	45	395	55
6mm<diameter≤20mm	250	35	325	45