Cold galvanizing is similar to specialized paints used to paint materials and utensils. However, in addition to aesthetics, this coating also protects the material from the impacts of the environment and extends the structure’s life. Thanks to its convenience and many other benefits, the cold galvanized coating is gradually becoming a popular protective coating solution in many fields today. Let’s learn more about this paint in the content of the article below.
What is cold galvanizing? Properties and common applications
The advent of cold galvanizing paint has become an alternative to hot galvanizing in many applications. With increasing demand, many types of galvanized paint with various features and color palettes were researched to meet users’ needs. So, what is cold galvanized paint? What salient features do they have?
What does cold galvanizing mean? The cathodic protection solution
The application of Zinc dust combined with organic or inorganic binders (by brush or spray) is known as “Cold galvanizing” or “Zinc painting.” Cold galvanizing is the technique of painting steel buildings and exteriors using Zinc-rich paints instead of hot-dip galvanizing, which covers iron and steel by immersing them in a molten Zinc bath. These Zinc-rich paints, which typically contain 92 – 95% metallic Zinc in the dry film, may be applied on steel structures and pipelines subjected to corrosive air settings such as refineries, power plants, bridges, buildings, mining equipment, and so on.
These paints can synergistically combine with the corrosion-inhibitive qualities of metallic Zinc since they include a high proportion of Zinc in the dry film. Zinc dust is used with organic binders in paint. These binders keep the Zinc particles in touch with one another, allowing the Zinc paint to give cathodic protection.
Properties of cold galvanizing – The outstanding advantages of galvanized
It can be said that cold galvanizing is the solution to “challenge” rust and significantly prolong the life of the material. Only by directly thermal spray aluminium coating with zinc paint at ambient temperature, we will obtain a protective cover of the material by two mechanisms:
- Passive protection with an outer barrier similar to traditional paints
- Active protection against cathodic corrosion (galvanized coating)
For this method to be effective, zinc particles in the coating must be present in sufficient quantities to facilitate electrical conduction between the substrate and the coating. It should be emphasized that cold galvanizing is neither as strong nor as long-lasting as hot-dip galvanizing. However, due to its other distinct advantages, it remains the optimum choice for safeguarding metal surfaces.
Cold galvanizing has the following basic properties:
- Applications range: 40 μm to 80 μm DFT or up to 160 μm DFT in two coats
- Low levels of VOCs (volatile organic compounds)
- Zinc painting may be used on both fresh and rusted substrates, as well as existing hot-dip galvanizing
- It can be used as a stand-alone coat or primer in a duplex system (with a corresponding topcoat)
- Cold galvanizing can be used to restore the cathodic protection of an existing galvanized corrosion, scratch, and impact resistance are excellent
- Temperature resistance ranges from -80°C to +200°C/250°C
- Temperature range of application: -10°C to +40°C
- It has exceptional resistance to the marine environment, is acid/alkali resistant, and may be used in pH ranges of 5.5 to 12.5
- High plasticity without breaking or crazing – permits metal substrate to expand
- Weldability: a 40 μm thick coat may be welded without affecting the weld junction
- Conductivity: the dry film has an extremely high conductivity.
- Salt spray: ISO 7253 – 4,200 hours
What is cold galvanizing used for? Great applications of Zinc painting
In addition to protecting metal from oxidizing corrosion and increasing the product’s aesthetics, cold galvanizing paint also protects and resists friction from external influences effectively. Galvanized paint is applied to materials of considerable size, complex or fixed structures such as pipelines, roads, bridges, irrigation, seaports, etc. Besides, it is also popularly used for plating in recent years.
This galvanizing method is applied for the following purposes:
- Paint repair hot-dip galvanized layer damaged by welding, cutting, drilling holes.
- Hot-dip galvanized resurfacing paint is corrosive to the environment over time.
- Galvanizing at the construction site or production site without having to put it in the plating workshop.
- Primer for any metal texture in combination with a traditional topcoat to get the color you want.
- Create a coating capable of protecting the surface, anti-corrosion, anti-rust.
Areas of application can include:
- Power poles, transmission towers, lighting poles, parabolic antennas, radar stations.
- Steel structure works, wharves, factories, offshore equipment, tanks, pipelines.
- Maintain equipment and accessories in power distribution, transmission, and substation systems.
- Power projects, oil, and gas, transportation, fisheries, chemicals, shipbuilding, wastewater treatment.
Read more: A proper guideline for the surface preparation process that you should know
With many outstanding features and dual protection of barrier and cathode protection, cold galvanizing products are widely used in many industries. The zinc painting industry is becoming increasingly diverse to fulfill various coating needs. Therefore, it is necessary to assess the specific situation and choose the most suitable coating solution.