What is galvanization

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What is galvanization?
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• Galvanization (or galvanizing as it is most
  commonly called in that industry) is the process
  of applying a protective zinc coating
  to steel or iron, to prevent rusting. The most
  common method is hot-dip galvanizing, in which
  parts are submerged in a bath of molten zinc.

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Protective action

• Galvanising protects the base metal in three
  ways
• It forms a coating of zinc which, when intact,
  prevents corrosive substances from reaching the
  underlying steel or iron.
• The zinc serves as a sacrificial anode so that
  even if the coating is scratched, the exposed
  steel will still be protected by the remaining
  zinc.
• The zinc protects its base metal by corroding
  before iron. For better results, application
  of chromates over zinc is also seen as an
  industrial trend.

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Methods

• Hot-dip galvanizing deposits a thick, robust
  layer of zinc iron alloys on the surface of a
  steel item. In the case of automobile bodies,
  where additional decorative coatings of paint
  will be applied, a thinner form of galvanizing is
  applied by electrogalvanizing. The hot-dip
  process generally does not reduce strength on a
  measurable scale, with the exception of
  high-strength steels where hydrogen
  embrittlement can become a problem. This
  deficiency is a consideration affecting the
  manufacture of wire rope and other
  highly-stressed products.

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• The protection provided by hot-dip galvanizing is
  insufficient for products that will be constantly
  exposed to corrosive materials such as acids,
  including acid rain in outdoor uses. For these
  applications, more expensive stainless steel is
  preferred. Some nails made today are galvanized.
  Nonetheless, electroplating is used on its own
  for many outdoor applications because it is
  cheaper than hot-dip zinc coating and looks good
  when new. Another reason not to use hot-dip zinc
  coating is that for bolts and nuts of size M10
  (US 3/8") or smaller, the thick hot-dipped
  coating fills in too much of the threads, which
  reduces strength (because the dimension of the
  steel prior to coating must be reduced for the
  fasteners to fit together). This means that
  for cars, bicycles, and many other light
  mechanical products, the practical alternative to
  electroplating bolts and nuts is not hot-dip zinc
  coating, but making the fasteners from stainless
  steel.

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• The size of crystallites in galvanized coatings
  is a visible and aesthetic feature, known as
  "spangle". By varying the number of particles
  added for heterogeneous nucleation and the rate
  of cooling in a hot-dip process, the spangle can
  be adjusted from an apparently uniform surface
  (crystallites too small to see with the naked
  eye) to grains several centimetres wide. Visible
  crystallites are rare in other engineering
  materials, even though they are usually present.

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Galvanized construction steel

• This is the most common use for galvanized metal,
  and hundreds of thousands of tons of steel
  products are galvanized annually worldwide. In
  developed countries most larger cities have
  several galvanizing factories, and many items of
  steel manufacture are galvanized for protection.
  Typically these include street furniture,
  building frameworks, balconies, verandahs,
  staircases, ladders, walkways, and more. SGCC hot
  dip galvanized steel is also used for making
  steel frames as a basic construction material for
  steel frame buildings.

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Galvanizing companies in uae

• Juma Fadhil Metal Industries
• P.O.BOX 526Phone [phone]Fax 971 6
  7436503Address Amman StreetNew Industrial Area
  2,Ajman, United Arab EmiratesEmail
   info_at_jfindustries.org