Robust, strong, and versatile, steel is the most widely used metal not just in the UK but on the planet. The metal is used for a huge number of applications in myriad industries, and the demand for it keeps growing. However, despite the many advantages, even high-quality steel tends to corrode. Read on and learn more about steel corrosion and how to prevent it.
Steel corrosion is the process that occurs when the metal comes into contact with various substances in the immediate environment and undergoes a chemical reaction that reduces its integrity.
Some of the substances that can cause steel to corrode include oxygen, salt, and sulphur. What those substances do to the metal depends on the chemical reaction they cause.
Let’s take a closer look at what causes corrosion of steel.
Oxygen: When steel is exposed to water, the oxygen in the water reacts with the iron in the steel. This reaction leads to the formation of iron oxide, better known as rust. This is arguably the most common cause of corrosion in steel.
Chlorides: Chloride is a naturally occurring electrolyte mineral and a common cause of stainless steel corrosion. The chloride ions in sea water and in de-icing salts can degrade steel surfaces’ protective oxide layer, which increases the corrosion rate.
Carbon dioxide: When carbon dioxide, a naturally occurring gas, dissolves in water, it forms a weak acid known as carbonic acid. Despite this acid’s weakness, it’s still strong enough to react with steel over time, even if oxygen isn’t present. Furthermore, carbon dioxide lowers water’s pH, increasing its acidity and, with it, the process of corrosion.
Humidity/moisture: The moisture present in the air in high humidity can contribute to corrosion. The moisture reacts with the steel’s iron to contribute to the formation of rust. This is due to the presence of oxygen in the water molecules in the air.
Air pollution: Nitrogen oxides, sulphur dioxide, and other air pollutants can also contribute to steel corrosion through the formation of acid rain.
Temperature: The chemical reactions responsible for corrosion tend to occur at a faster rate in higher temperatures. This can speed up the corrosion process.
The three main types of steel corrosion are:
Some of the most common methods of preventing steel corrosion include:
Shotblasting sees specialised equipment direct tiny abrasive elements at the steel, stripping the top layer of the metal. This removes rust, dirt, imperfections, and cosmetic damage in preparation for painting.
The paint coatings form protective layers on the metal’s surface, protecting it from corrosive compounds’ electrochemical charge. The primer coat inhibits steel corrosion, the middle coat contributes to the paint’s thickness, and the finish coat increases resistance to environmental factors.
General maintenance can go a long way to identifying and resolving or preventing steel corrosion problems before they become far worse. Ensure you inspect steel elements regularly, clean them thoroughly, repair any damage you identify, and reapply any protective coatings as and when necessary. You may also need to replace corroded sections of steel, reinforce weak areas, and increase your corrosion protection and prevention measures.
Paint isn’t the only protective coating for steel. You can also find powders and waxes designed to offer protection against the causes of corrosion.
One of the best-known protective coatings for steel is zinc. There are several different methods of galvanising steel with zinc, all of which see the element bonded to the steel as a result of a natural metallurgic reaction. This creates a physical barrier that corrodes at a slow rate, effectively being sacrificed before the steel begins to corrode.
Choosing a corrosion-resistant alloy for specific applications can help reduce the risk of corrosion. Stainless steel is corrosion resistant to a point, although it’s certainly better performing in this regard than regular carbon steel.
With care, maintenance, and proven steel corrosion prevention measures, high-quality steel has an incredible lifespan. If you require carbon or stainless steel for your project, make sure that you can choose metal products that you can trust. Order the best steel conveniently online or contact our friendly team to place special orders. If you have corroded steel components, be sure to take advantage of our shotblasting and painting services.
