What is hot dip galvanizing? All about hot-dip plating you need to know

What is hot dip galvanizing

Hot-dip galvanizing is one of the surface technologies by coating metal with a thin layer of zinc by dipping the surface-treated protective metal into a bath of molten zinc. Hot dip galvanizing is also known as galvanizing.

Of all the popular surface techniques for steel, galvanizing is the most resistant to rust.

During galvanizing the metal is smelted into an alloy with the substrate. So the galvanized layer will not peel off like when using paint to create a permanent protective layer for the substrate.

History of hot-dip plating technology

In 1742 when a French chemist named Melouin, in a presentation at the French Academy, described a method to protect the surface of iron and steel parts by dipping it in a bath of molten zinc.
In 1836, Sorel was a French chemist who received a patent for a method to protect the surface of iron and steel by a zinc coating by dipping the part in a bath of molten zinc after having treated the surface of the part with acid. 9% sulfuric acid and dipped in Amonium Chloride. Another British patent was also granted in 1837.
Since 1850, the hot-dip galvanizing industry in England has used 10,000 tons of zinc each year to protect iron and steel. Hot-dip galvanizing to protect the surface of iron and steel has been widely applied in almost all sectors of the economy such as power transmission, transportation, paper mills, chemical plants…
Over the past 150 years, hot-dip galvanizing has proven to have a history of commercial success as a method of corrosion protection in a multitude of applications around the world.

Hot dip galvanizing and actual values

Using a protective coating (also known as barrier protection) to isolate metal surfaces exposed to capacitive substances in the external environment is the oldest and most widely used method of corrosion protection. trail. The two most important properties of a barrier protection layer are adhesion to the base metal surface and the durability of the coating. Paint is a good example of barrier protection. Cathodic protection is an important method to prevent corrosion, the essence of cathode protection is to change the element of the corrosion circuit, creating a new element of the corrosion circuit and ensuring that the base metal becomes cathode element of this circuit. Hot-dip galvanizing is a method that simultaneously provides two methods of corrosion protection: barrier protection and cathode protection.
Zinc has long been used to create a protective layer due to its properties (Zn’s corrosion rate is 40-50g/m2/year compared to 400-500g/m2/year for steel, with Zn again. carries a potential + compared to Fe in the process of electrochemical corrosion…), in principle, no matter what method it is created by: Electroplating, hot-dip plating, spray plating, the decisive factor to the life of the protective Zn layer is the thickness of the coated Zn layer.
With the superior properties of protective surface coating, Hot Dip Galvanizing is showing useful values. Hot molten zinc dipping technology ensures the quality of structural steel constructions in the period of industrialization and modernization of the country.
Create a protective layer for metal structures in air, marine, industrial gas…
The zinc coating after drying has two protective functions:
The first is the passive protection function with a metal protective film like traditional paints;
The second is active protection, or cathodic protection, which is available in hot-dip galvanizing protective coatings.
Restore worn parts: refresh the product surface when affected by environmental factors.
Creates a durable wear-resistant layer on new components.
Create a decorative layer on top of plastic, wood…
The most common is still creating a layer of zinc, aluminum to resist corrosion in different conditions