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Hot dip galvanizing: what it is and how it works against corrosion


Hot-dip galvanizing is an essential process in metallurgy, offering effective protection against corrosion and oxidation of metals. We will discover what this crucial process is and how it works.

What is hot-dip galvanizing?

Hot-dip galvanizing is a technique for coating metals by immersion in molten zinc alloy. This process creates a protective layer of zinc on the surface of the metal, offering lasting protection against corrosion and oxidation. Hot-dip galvanizing is widely used in industry to preserve the integrity and durability of metals.

How does hot-dip galvanizing work?

The hot-dip galvanizing process has several steps:

  1. Cleaning of the surface: before immersion in the molten zinc alloy, the surface of the metal is carefully cleaned to remove any contaminants, oils, grease or oxides that could compromise adhesion of the zinc layer.
  1. Pre-heating: the metal is then pre-heated to ensure it is at the optimal temperature for immersion in the molten zinc alloy. This step improves adhesion of the layer of zinc and facilitates even distribution of the coating.
  1. Immersion in the molten zinc alloy: the metal part is then immersed in the molten zinc alloy at a temperature of approx. 450–460°C. During immersion, the molten zinc bonds chemically to the surface of the metal, creating a protective layer that is resistant to corrosion and oxidation.
  1. Cooling and solidification: after immersion, the galvanised metal is slowly cooled to allow the zinc alloy to solidify and strongly adhere to the surface of the metal. This solidification process guarantees the formation of a uniform and resistant protective layer.
  1. Quality control: once the hot-dip galvanizing process is complete, the galvanized metal undergoes rigorous quality-control checks to ensure that the protective layer is uniform, adherent and without defects.

Benefits of hot-dip galvanizing

Hot-dip galvanizing offers a series of important benefits:

  • High level of corrosion resistance: the layer of zinc created by hot-dip galvanizing provides exceptional protection against corrosion and oxidation, extending the useful life of the metal and reducing the need for maintenance.
  • Durability and long life: zinc plating is extremely durable and resistant to wear, guaranteeing long-term protection even under the most aggressive environmental conditions.
  • Galvanic protection: hot-dip galvanizing provides galvanic protection, reducing the risk of galvanic corrosion caused by contact between different metals.
  • Versatility: hot-dip galvanizing can be applied to a wide range of metals, including steel, iron, aluminium and copper alloys, making it suitable for many different industrial applications.
  • Efficiency and savings: compared to other methods used to protect metals, hot-dip galvanizing is relatively economic and very cost effective, guaranteeing high-quality protection at an accessible price.

Applications of hot-dip galvanizing: protection in the different industries

Hot-dip galvanising is employed in a wide range of industrial sectors for its ability to protect metals from wear, corrosion and oxidation. Let’s take a closer at applications in key markets:

  • Automotive: in this sector, hot-dip galvanizing is used to protect a wide range of metal components and structures used to manufacture vehicles. These components include parts of the frame, bodywork, bolts, screws, mounts and springs. The corrosion resistance offered by hot-dip galvanizing maintains the structural integrity of vehicles and their aesthetics, even in the most challenging environmental conditions.
  • Construction: in the building industry, hot-dip galvanizing is used to protect metal structures for buildings and infrastructure. These include beams, columns, railings, handrails, brackets, nails and bolts. Hot-dip galvanizing ensures these structures are able to withstand weathering, humidity and corrosion, extending the life of buildings and guaranteeing the safety and stability of the structures.
  • Maritime industry: in this sector, hot-dip galvanizing is essential to protect ships and other marine structures from wear caused by the aggressive marine environment. Hot-dip galvanized parts and components, including hulls, support structures, anchors and chains, are able to withstand the corrosion caused by saltwater and weathering, guaranteeing the safety and durability of vessels.
  • Infrastructure sector: here, hot-dip galvanizing is used to protect a wide range of structures and components used for civil-engineering projects and public infrastructure. These structures include bridges, walkways, road barriers, guardrails, steel cables and support pillars. Hot-dip galvanizing ensures that this infrastructure can withstand weathering, corrosion and rust, extending its useful life and guaranteeing public safety.
  • Agricultural sector: in the farming industry, hot-dip galvanizing is used to protect a range of equipment and structures used in agricultural operations. This includes fencing, gates, structures for housing animals and barns for equipment. Hot-dip galvanizing ensures that this equipment is able to withstand tough environmental conditions and the high levels of corrosion typical of the agricultural environment, guaranteeing durability and lasting functionality.