How to Protect Metals from Corrosion
Corrosion is something we need to prepare for and try our hardest to prevent, especially when talking about metals. Short Iron Store wants to help you understand this problem. Every year corrosion breaks down machinery, buildings and equipment. This costs the American industry an estimated $7 billion. Corrosion is a costly problem. We need to understand its basic causes, and then find the effective steps that can be taken to prevent and combat it.
What is corrosion?
When iron or steel corrodes, the result is iron oxide, or what we call rust. Steel is mostly made up of iron ore. In its natural state, iron ore looks much like rust: dark red with a tendency to hold moisture. (Red mud/dirt gets its color from iron)
Iron ore is a stable substance. Once it is converted into iron or steel, they become weaker elements. When steel is exposed to moisture and oxygen, it immediately starts changing back to its natural state.
Even though protective measures are taken, a large part of the steel made has already rusted back to an oxide, its natural state.
Three elements are required for corrosion to exist: a protected metal, a corroded metal, and a current-conducting medium between the two. This medium is normally a liquid or water-containing substance. The medium conducts the corrosion current from the protected metal to the corroded metal. The most common current-carrying substance is water. Steel corrodes very slowly in desert climates where humidity is low and rainfall rare. In areas of high humidity and frequent rain, protecting steel is critical.
What to do?
Impressed current, also called electrochemical corrosion protection – (impressed uses external sources and electrochemical uses natural sources) By using suitable current-generating equipment and controls, it is possible to reproduce a current equal in strength to the corroding current, but flowing in the opposite direction. This type of protection is generally limited to pipelines, buried tanks, etc., and requires careful engineering and layout.
Corrosion protection by coating/ Primers– Primers and finished coatings protect metal surfaces by providing a barrier between the steel and the corroding elements. They also prevent moisture from reaching the surface of the steel. A coating film protects the underlying metal. With this type of protection, the first thing that is needed is to remove any corrosion. This is normally done by grinding, brushing, polishing, blasting or blotting. The coatings are then applied to the material.
Use Galvanized Metal –
Galvanization is a process used to preserve and keep steel rust-free for many years. In the galvanizing process, a piece of steel is coated with liquid zinc. The zinc protects the steel in three different ways. First, the zinc coating acts as a barrier preventing oxygen and water from reaching the steel. Second, even if the coating is scratched off, the zinc continues to protect nearby areas of the metal. Lastly, zinc is highly reactive to oxygen and quickly forms a protective coating of zinc oxide which prevents the iron from further oxidation.
Watch for any signs of corrosion and address them immediately. If you have any questions or concerns please contact us at Short Iron Store.