Zincatura Sigillo verde

SIGILLO VERDE® hot-dip galvanising is a metallurgical treatment that protects against rust. It is a technological evolution of traditional hot-dip galvanising carried out according to the new international standards and increasing requirements of environmental sustainability.


High resistance
SIGILLO VERDE® hot-dip galvanising is an actual alloy between steel and zinc. This results in a very tough surface that is difficult to scratch. It is highly resistant to scrapes and abrasions. It can be handled without special care and precautions.

Active protection
Where it is scratched, and the steel has been revealed, the cathode effect is activated which limits the formation of rust in the scratched area alone.

Internal and external protection
The process creates a steel-zinc alloy layer on both the outer surfaces and inner surfaces (example: a tube).

None structural alteration
The class 1 zinc coating, according to EU regulation EN 24286, and where allowed, makes it possible to avoid the radiographic testing of welding seams and product components as provided by EN 1090.



SIGILLO VERDE® hot dip galvanising allows you to:

  • Protect steel from rust, or what we commonly call iron
  • Eliminate the typical maintenance against rust on metal products protected with paint
  • Preserve the structural characteristics of the metal elements
  • Safeguard the sturdiness of the weld seams
  • Preserve the environment and non-renewable resources
  • Declaration of Conformity according to the UNI EN 10204 standard for every lot

SIGILLO VERDE® hot-dip galvanising can be performed on all manufactured products made of carbon steel, commonly called "iron" with maximum dimensions of 13,000x2,000x3,200mm 6.000 kg max.
SIGILLO VERDE® hot-dip galvanising is an anticorrosive system that can be used in all environments: natural, urban, industrial areas and even in aggressive environments such as wetlands, marine and heavy industry zones. It can also be used to protect metal elements that are installed immersed in the sea, lagoons or rivers.
By definition, hot-dip galvanising is a metal casting corrosion protection treatment with no aesthetic value, other than its natural conformation and transformation over time.
SIGILLO VERDE® hot-dip galvanising is used for the protection of gates, fences, railings, beam structures, pergolas, gazebos, trellises, urban furniture, lamp posts, industrial plant structures, lofts. View some application examples in the "Projects" section.


SIGILLO VERDE® hot-dip galvanising is performed according to European UNI EN ISO 1461 standard or, on request, according to other international standards such as the American ASTM.
After a series of immersions in the preparation baths, the metal parts are submerged in a tank containing molten zinc at 450°C.
The zinc combines with the carbon present on the surface of the article forming a surface alloy with a thickness which can vary from 50 to 150 microns.


SIGILLO VERDE® hot-dip galvanising is delivered with a user and maintenance manual, an interesting guide on how to enjoy and prolong the anti-corrosive performance of the treatment to the utmost. You can download the manual and other technical documentation in the download section.


SIGILLO VERDE® hot-dip galvanising is performed in a Class 1 zinc bath according to EU standard EN 24286, the only one that allows us to preserve all the mechanical characteristics of steel and weld seams otherwise to be verified, as required, according to EU Standard EN 1090. The SIGILLO VERDE® hot-dip galvanising is performed using EMAS approved systems, the European environmental management regulation, and has an Environmental Product Declaration EPD.


"The zinc coating provides corrosion protection by sacrificing itself instead of the" iron" and, thanks to its oxidation times, significantly higher than those of iron, it guarantees protection for several years. The hot-dip galvanising method has different life expectancies depending on the environment in which it operates. To determine the life expectancy, it is therefore necessary to identify the Category of Environmental Corrosion relative to the installation site. UNI EN ISO 14713-1 assigns a corrosion rate expressed in uM / year" for each category of corrosion


Hot-dip galvanising is a surface treatment applied to steel elements that require effective corrosion protection.
Unlike traditional corrosion protection coatings that passively coat the metal, using hot-dip galvanising it is possible to obtain a chemical-metallurgical interpenetration between steel and zinc, capable of providing prolonged protection against corrosion and mechanical stress.


The paragraphs below provide a short description of the main treatment phases:
  • PREPARATION: the materials are hung using iron wire and/or chains/equipment to "frames" to allow handling throughout the entire production process.
  • DEGREASING: removal of oil and grease from the surfaces of the manufactured elements by immersion in an acidic degreasing solution, with the addition of surfactants.
  • PICKLING: elimination of the iron oxides and ferrous rolling mill residues, by immersion in solutions composed of Hydrochloric Acid (HCl) and Water (H20).
  • WASHING: elimination of acid residues, left by previous phases, by immersion and rinsing in water.
  • FLUSHING: immersion of the elements in an aqueous solution of "double salt" consisting of Zinc Chloride and Ammonium Chloride (ZnCl2-2NH4Cl).
  • PREHEATING: the elements are heated in a drying oven at about 100-120°C so as to dry the flushing salts and reduce the thermal shock when it is immersed in the galvanising bath.
  • GALVANISING: immersion in a bath of molten zinc (min. Zn 98.5%) at a controlled temperature of 440-450°C.
  • COOLING: Natural air cooling at room temperature.
  • REMOVAL AND CONTROL: removal of the material from the frames, quality control and finally packaging and finishing.
  • UNI EN ISO 1461 “Hot-dip galvanising”
  • UNI EN ISO 14713 “Hot-dip galvanising”
  • ASTM A 123 "Hot dip galvanising - USA"

The SIGILLO VERDE® hot-dip galvanising must be carried out at the Nord Zinc spa facilities. It can not be done on-site and it is therefore necessary for the product manufacturer to deliver the parts to the facilities for processing."