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5 Types of Steel Corrosion and Treatments Against Them

Regardless of the project, you’re working on, protection against steel corrosion is a primary concern of every construction project. Despite its strength and versatility, steel will eventually develop rust. 

The good news is that this development can be reconciled with steel surface treatment provided by structural steel and fabrication specialists. Doing this prevents corrosion effectively. 

What Is Steel Corrosion?

Steel corrosion is a deterioration caused by electrochemical reactions between the metal and its environment. Steel, in particular, develops rust when the iron oxidises. For corrosion to occur, both oxygen and water must be present.

Corrosion happens most commonly in humid environments, where moisture and salty water speed up the corrosion process. However, this can also occur in the absence of water when the iron oxidises in the atmosphere. This process is called dry corrosion, and it accelerates in higher temperatures. 

5 Steel Corrosion Types

There are numerous types of steel corrosion, but the following five are the most common:

  • Galvanic Corrosion: Also known as metal corrosion, occurs when steel comes into contact with another metal in a corrosive electrolyte.
  • Uniform Attack Corrosion: Also called general attack corrosion, this results in the deterioration of all exposed surfaces. It is the most common kind of decay in steel.
  • Intergranular Corrosion: This corrosion is seen along the boundaries of metal crystallites or grains. 
  • Pitting Corrosion: This type of corrosion happens when localised areas of steel lose their protective layer. As this area becomes anodic and the rest remain cathodic, a localised galvanic reaction is produced.
  • Crevice Corrosion: Just like pitting, this corrosion type is localised, usually in a stagnant microenvironment where acidic conditions, such as oxygen depletion in a crevice, result in corrosion.

Treating Steel Surface Against Corrosion

Surface treatment remains the most effective way of protecting steel against corrosion. Here are some of the best treatments steel fabricators use:

  • Chemical Coating: This uses electrostatic or compressed air to apply a specially formulated powdered material onto the surface. Then, it is melted to create a smooth coating that protects against corrosion and ultraviolet (UV) damage. Moreover, it is also resistant to peeling, cracking and scratching.
  • Hot Dipping: This galvanisation method is compatible with all shapes and sizes of steel. It immerses the steel in a bath of molten zinc at a temperature of up to 450°C. Steel treated this way protects against corrosion and extreme weather conditions, making it popular for pipe-related applications.
  • Zinc Phosphate Priming: Steel surfaces can be painted with specially formulated primers that improve corrosion resistance. It also boosts visual appeal, making it a popular application, especially zinc phosphate priming.
  • Zinc Spray Metallising: This technique is highly effective against corrosion, though it doesn’t offer the same protection as hot-dip galvanising. This cold process does not risk distorting the metal, and its smooth finish makes it ideal for ornate metal components like fences and railings.

Conclusion

Steel corrosion can happen to essential construction materials if not appropriately treated. It can cost an entire project, so it is vital to ensure high corrosion resistance in your steel materials. Be sure to seek a steel specialist who will check the integrity of your steel and ensure that all materials are up to standard. 

Phoenix Reinforcing is a structural steel and fabrication specialist in the Sunshine Coast, providing everyone from the DIY customer to the Construction trade with quality workmanship by our team of boilermakers that have combined industry knowledge of over 40 years! We offer a full delivery service with local deliveries run from our Noosa store. Get in touch with us today and let us know how we can help! 

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