Resistances Mag'

Edito News Back to Basis Quality Technology and Technic Organisation Chart
Quality

DEFINITION A BIT OF HISTORY...
"THE GALVANIZATION PROCESS"
(Source: Wikipedia Encyclopedia)

In current use, "galvanization" typically means hot-dip galvanizing, a metallurgical process that is used to coat steel or iron with zinc. This is done to prevent corrosion (specifically rusting) of ferrous items; while it is accomplished by non-electrochemical means, it serves an electrochemical purpose.

Galvanization is the process of coating a base metal, such as iron, with a thin layer of zinc to protect the base metal from corrosion. The zinc layer protects the base metal even when there are cracks or small gaps in the coating, because oxygen reacts more readily with zinc than with the exposed base metal.

Hot-dip galvanized steel has been effectively used for more than 150 years. The value of hot-dip galvanizing stems from the relative corrosion resistance of zinc, which, under most service conditions, is considerably better than iron and steel. In addition to form a physical barrier against corrosion, zinc, applied as a hot-dip galvanized coating, cathodically protects exposed steel.

Furthermore, galvanizing for protection of iron and steel is favored because of its low cost, the ease of application, and the extended maintenance-free service that it provides.

Originally, galvanization was the administration of electric shocks (in the 19th century also termed Faradism, after Michael Faraday).

FrogIt stemmed from Luigi Galvani's induction of twitches in severed frogs' legs, by his accidental generation of electricity.
It had been found that a charge applied to the spinal cord of a frog could generate muscular spasms throughout its body. Charges could make frog legs jump even if the legs were no longer attached to a frog.
While cutting a frog leg, Galvani's steel scalpel touched a brass hook that was holding the leg in place.
The leg twitched.

In honor of Galvani's research, Volta coined the term galvanism for a direct current of electricity produced by chemical action. Galvani's name is still associated with electricity in the words galvanism and galvanization.

Later, the word "galvanic" was used for processes of electro deposition. This remains a useful and broadly applied technology, but the term "galvanization" has largely come to be associated with zinc coatings, to the exclusion of other metals.

For more details, please click on this link 
QUALITY STANDARDS
GALVANIZING: The best and most economical protection for steel ensuring long-lasting protection.

To hot dip galvanize a metal item, it is first cleaned and fluxed then dipped into a bath of melted zinc (at 450°C). This process gives galvanization its specific qualities:

- Ideal attachment of the zinc coating
- Corrosion resistance
- Abrasion resistance
(A certain aptitude for deformation) limited susceptability to damage.

Hot Dip Galvanized Process
following  International Standards ISO 1461
325g/m²  for th < 1,5 mm 45 µm
395g/m² for th 1,5  mm < th  < 3 mm 55 µm
505g/m² for th 3  mm < th  < 6 mm 70 µm
For more details, please click on this link
Hot Dip Galvanization on Continuous Line
following  Sendzimir Process Z275
275g/m² for 25 µm
WARNING
Sometimes, following the Hot Dip Galvanized Process, it may happen that some steel areas "do not look nice" and appear as if it was rusting. However, this phenomena is induced by the galvanizing process itself. Indeed:
  • When Zinc is melted to have that liquid coating which will cover the framework, some air bubbles are sometimes jailed in the bath.
  • These bubbles do burn and do look like impurities but they are not.
  • These bubbles cannot be avoided but do not have any bad effect on the protection principle, i.e. Hot Dip Galvanizing Process. 
  • When such a phenomena occurs, do not do anything on it (except from  putting Zinc Paint on it) and above all, do not grind them or you would poor the protection given by the Hot Galvanizing Process.