In extreme environments, the service life of metallic structures can be threatened by corrosion. Corrosion protection is a critical factor in the durability of such structures, especially in aggressive environments. Two of the most commonly used methods to protect steel are hot-dip galvanizing and high-strength coating. Although both processes have the same objective – to protect steel against rust and wear – their compositions and performances present key differences as an ideal option for all types of projects.
Hot dip galvanizing: the traditional method
Hot-dip galvanizing finishing is a process widely used in the industry. It consists of immersing the steel in a bath of molten zinc, which generates a protective layer that adheres firmly to the surface. This layer acts as a physical barrier against corrosion and, in case of damage, provides cathodic protection to the exposed steel.
It is an effective and cost-efficient technique, widely used in construction, automotive and public infrastructure. However, its performance may be limited in particularly aggressive environments, such as coastal areas or areas exposed to chemicals.
High Resistance: advanced coating technology
The High Resistance finish is an evolution of traditional galvanizing. It is a metallic coating that is also applied by hot dip, but with a special alloy composed of approximately 93.5% zinc, 3.5% aluminum and 3% magnesium. This composition gives it unique properties against corrosion.
Thanks to the presence of magnesium, zinc and aluminum, a very stable and highly resistant layer is formed, which even offers a self-repairing effect in cuts and edges, where corrosion is normally concentrated. This characteristic makes it ideal for applications in extreme environments such as acidic soils, industrial atmospheres or marine environments.
If we focus on corrosion protection:
Hot dip galvanized:
- Good in normal outdoor environments; rapid degradation in aggressive environments (marine, industrial).
- The coating may be porous and does not cover cut edges well; risk of corrosion in deformed areas.
High resistance:
- Much more resistant to corrosion, up to 3 times more than traditional galvanizing.
- Excellent performance in aggressive environments (saline water, industrial atmospheres, acidic soils).
- Uniform coating even on deformed areas allowing self-repair to occur, covering exposed edges within weeks/months
Let’s talk about coating thickness and durability:
Hot dip galvanized:
- Requires greater Zn thickness to achieve durability (> 20 µm typical; depending on application).
- Generally requires thicker coats for greater protection.
- No specific warranty; moderate service life (< 15 years in harsh environments).
High resistance:
- More efficient and lighter for certain applications.
- 20-25 year warranties on solar, marine, agricultural and industrial applications; allowing for minimum maintenance
- Magnesium reinforces the oxide barrier, reducing corrosion initiation points.
- Very good flexibility in bending and folding, with minimal cracking.
Typical applications:
Hot dip galvanized:
- Protection of port structures, bridges and poles (aggressive environments).
- Ideal for parts with simple and accessible geometry.
- Widely used in construction and civil works.
High resistance:
- Ideal for structures exposed to aggressive conditions, such as:
- Solar panels
- Agricultural infrastructure
- Components in marine or industrial environments
- Drainage and canalization systems
Environmental care and sustainability:
Hot dip galvanized:
- Uses more zinc; may have greater environmental impact.
- High energy consumption for manufacturing
High resistance:
- It uses less zinc and performs better, making it more sustainable in many cases.
- Greater durability reduces the frequency of coatings or repairs, saving resources in the medium term.
In short, a summary of advantages:
Hot-dip galvanizing is still a widely used solution to protect steel. However, for more demanding conditions, increased durability and strength, our High Strength finish offers a state-of-the-art alternative with longer service life and less maintenance in the long run.