BS EN 10346:2009 (formerly BS EN 10142:1991) Coating type: Z120, Z180 Z275 ASTM A 653A653M.

BS EN 10088-2:2005 which was direct equivalent to formerly BS 1449: Part 2: 1983 in Grade 304 2B FINISH, ASTM A240A240M in Grade 304 2B FINISH.

The actual thickness of galvanized coating achieved varies with steel section size, surface profile and surface composition.

Actual coating weights are often much more than the minimum specified in the standard.

As coating life expectancy figures quoted are based on the minimum coating thickness they are therefore usually very conservative.

It is important, therefore, that the users requirements for galvanizing are made clear to the fabricator and that all communications concerning galvanizing are channelled through the fabricator.

It should however, be emphasised that for most applications, thicker coatings are rarely necessary.

For structural steelwork, it is advisable to ascertain whether thicker coatings could be achieved through their greater section thickness and without grit blasting.

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Find sources: Hot-dip galvanization news newspapers books scholar JSTOR ( November 2013 ) ( Learn how and when to remove this template message ).

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).

It can be identified by the crystallization patterning on the surface (often called a spangle).

Galvanized fumes are released when the galvanized metal reaches a certain temperature.

In long-term, continuous exposure, the recommended maximum temperature for hot-dip galvanized steel is 200 C (392 F), according to the American Galvanizers Association.

The use of galvanized steel at temperatures above this will result in peeling of the zinc at the inter metallic layer citation needed.

Electrogalvanized sheet steel is often used in automotive manufacturing to enhance the corrosion performance of exterior body panels; this is, however, a completely different process which tends to achieve lower coating thicknesses of zinc.

However, zinc is a more electropositive (active) metal in comparison to steel.

This is a unique characteristic for galvanizing, which means that when a galvanized coating is damaged and steel is exposed to the atmosphere, zinc can continue to protect steel through galvanic corrosion (often within an annulus of 5 mm, above which electron transfer rate decreases).

The resulting coated steel can be used in much the same way as uncoated.

The flux is allowed to dry on the steel and aids in the process of the liquid zinc wetting and adhering to the steel.

Environmental regulations in the United States disapprove of lead in the kettle bath.

Lead is either added to primary Z1 grade zinc or already contained in used secondary zinc.

Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc, such as roofing and walling, safety barriers, handrails, consumer appliances and automotive body parts.

Galvanised steel is also used in most heating and cooling duct systems in buildings.

Other modern techniques have largely replaced hot-dip for these sorts of roles.

This includes electrogalvanizing, which deposits the layer of zinc from an aqueous electrolyte by electroplating, forming a thinner and much stronger bond.

The British, European and International standard for hot-dip galvanizing is BS EN ISO 1461, which specifies a minimum coating thickness to be applied to steel in relation to the steels section thickness e.g.

The durability performance of a galvanized coating depends solely on the corrosion rate of the environment in which it is placed.

Corrosion rates for different environments can be found in BS EN ISO 14713-1, where typical corrosion rates are given, along with a description of the environment in which the steel would be used.

GalvInfoNote The Spangle on Hot-Dip Galvanized Steel Sheet (PDF).

GalvInfo. Retrieved 27 February 2014.

Bs En Iso 1461