Steel corrosion is a process of electrochemical degradation that occurs when steel is exposed to moisture and oxygen. This corrosion can cause the structural integrity of steel to be compromised, as rust takes up more space than its predecessor. As a steel manufacturer, we constantly evaluate the quality of our steel and produce products of the highest grade to prevent against corrosion. It is important to understand how corrosion happens so that we can take steps towards preventing it from occurring. In this article, we will explore what causes corrosion of steel, why it happens, and how we can prevent it. 

What is Steel Corrosion?

The corrosion of structural steel is an electrochemical effect driven by the presence of moisture and oxygen. Iron in the steel corrodes, transforming into rust that takes up more space than its predecessor — approximately six times as much! Factors such as a structure’s microclimate greatly influence how quickly this corrosive transformation progresses.

How Does Steel Corrode?

Variations in composition, structure, impurities, and internal stress of steel can all contribute to an uneven corrosion process when exposed to a non-uniform environment. Furthermore, due to higher levels of recycled steel being used, there is an increased risk that such factors may be present.

In a small area of exposed steel, microscopic regions can easily become anodic or cathodic in comparison to one another. This can generate numerous distinct galvanic corrosion cells on the same region of actively corroding metal. Additionally, large numbers of such areas may develop within a tiny portion of that steel material.

Corrosion products gradually build up in certain areas of the metal, leading to an entirely altered composition from its original state. As these new components are brought to the surface, clear-cut differences between anodic and cathodic sites appear; this encourages previously unaffected steel portions to corrode more quickly as well. Resulting in accelerated decay on all surfaces – consequently speeding up corrosion of the entire steel body over time.

The corrosion products of steel are red-brown oxide particles which, when presented in even the tiniest amount, can cause a visibly corroded uncoated steel surface. While naturally exposed to the atmosphere and subject to corrosion over time, electrochemical cells on its outermost layer quicken this process considerably.

How do you prevent steel corrosion?

By understanding corrosion of steel and how it occurs, steps can be taken to prevent it. Such steps range from selecting the correct grade of steel for a particular application to coating it with corrosion-resistant protective coatings. The use of corrosion inhibitors is also an effective way to protect steels exposed to highly corrosive environments, such as immersion in water or exposure to acid rain.

No matter what steps you take, corrosion prevention should always start by selecting the proper grade of steel for the project environment. As a rule, higher corrosion-resistant alloys tend to be more expensive; however, it may be worth investing in such grades in order to reduce corrosion issues over the long term. The use of corrosion prevention products, such as corrosion inhibitors and protective coatings, can also help to extend the life of steel against corrosion.


Steel corrosion is an electrochemical process driven by the presence of moisture, oxygen, and other elements in a non-uniform environment. It is important to understand what causes corrosion of steel so that we can take steps to prevent it from occurring. By selecting the right grade of steel and utilizing corrosion inhibitors or protective coatings, we are able to increase corrosion resistance and ensure proper maintenance of steel structures over time.

At Bulldog Steel, we always use processes and base metals of the highest quality, producing the highest quality steel that is resistant to corrosion. Our protective paint systems from WeatherXL and Valspar are also 40-year paint systems. Contact us today with any questions and inquiries about our steel and building accessories.

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