Hot Dip Galvanized Steel Sheet

It is a coating thickness designation in the galvanizing specification astm a653.

Hot dip galvanized steel sheet.

Hot dip galvanizing is a process of coating steel with a thin zinc layer which serves as a barrier between the steel and the environment. Hdg steel products are prepared by plunging a steel product into a vat of molten zinc. This specification is for hot dip galvanizing steel sheet using the continuous high speed galvanizing process. Continuous sheet galvanizing is also a hot dip process but is only applied to steel sheet strip and wire.

Shanghai aiya industrial co ltd. Astm a123 standard specification of zinc hot dip galvanized coatings on iron and steel products refers to products fabricated and then hot dip galvanized. The steel is rinsed again immersed in a flux bath removed and allowed to dry. When exposed to the atmosphere the pure zinc zn reacts with oxygen o 2 to form zinc oxide which further reacts with carbon dioxide co 2.

G90 is not a galvanizing specification. Production of galvannealed sheet steel begins with hot dip galvanization of sheet steel. Hot dip galvanization is a form of galvanization it is the process of coating iron and steel with zinc which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around 449 c 840 f. The finish is applied by passing the steel through a molten bath of zinc at a high temperature.

A thin coat of zinc adheres to the steel part and is quickly oxidized by the surrounding atmosphere. A coil to coil process steel sheets from 0 010 to 1 70 inches 0 25 mm to 4 30 mm thick and up to 72 inches 1 830 mm wide is passed as a continuous ribbon through cleaning baths and molten zinc at speeds up to 600 feet per minute. Produces high quality hot dip galvanized steel coils and electrogalvanized coils. Protect against corrosion with hot dipped galvanized steel sheet and coil products from alliance steel.

In alternative processes the flux solution floats on the top of the molten zinc and the steel item receives the flux layer as it enters the hot dip tank to be galvanized. Hot dip galvanized hdg steel is often just called galvanized steel although the full name is more correct. After passing through the galvanizing zinc bath the sheet steel passes through air knives to remove excess zinc and is then heated in an annealing furnace for several seconds causing iron and zinc layers to diffuse into one another causing the formation of zinc iron alloy layers.