Corrosion is a natural process that happens when certain elements come into contact with each other. Corrosion, otherwise known as Rust, occurs on most metals if necessary precautions aren’t taken.
In this article, we will be addressing the various types of corrosion. Additionally, we will be looking at how we, at Aquadam, take precautionary steps to prevent rust from forming on our Steel Tanks.
What is Corrosion/Rust?
“Corrosion is a natural process that converts a refined metal into a more chemically-stable form such as oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment “
– Wikipedia
In layman’s terms, corrosion is when (mostly) metals react with their environment and break down into more simple elements. As a result of this, metals degrade over a period of time when it comes into contact with natural elements like water, air, and soil.
Different Types of Corrosion
When it comes to metal, there are a few different types of corrosions. We will be looking at 5 of these types today.
Galvanic
Galvanic corrosion is one of the most common types. It happens when two different metals (anodized metals and cathodic metals) are combined and can cause degradation. The ions transferred from the one metal to the other, can cause damage and corrode the weaker metal ( anodized metal ). Additionally, it can also occur when one impure metal is present.
Therefore, it is important to ask the right questions when buying a tank. Especially when you are planning on collecting rainwater. Ensure that your gutter’s metal and tank’s metals are compatible. Otherwise, Galvanic corrosion will most likely damage your steel tank.
Stress-corrosion cracking
Stress-corrosion is usually as a result of a high-pressure environment on the steel/metal. Due to the high pressure, it forms tiny cracks (that are sometimes not noticeable) but then slowly starts to corrode from there on out. This can cause severe damage and lead to structural damage beyond the point of repair. Additionally, fluctuating temperatures etc. can also cause these minor cracks and lead to damage.
Therefore, it is important to ensure that the steel tank has made provision for the pressure. At Aquadam, the tanks are designed by engineers who take all of these factors into consideration. The tanks are made with separate sheets of bolted metal and/or corrugated iron to ensure that it can handle any pressure. Additionally, the tanks come with a standard 25-year guarantee. Therefore, you have peace of mind knowing that the steel tanks are of the highest quality.
General Corrosion
This occurs as a result of rust. When metal is exposed to water, the surface is oxidized and a thin layer of rust appears. Like galvanic corrosion, general corrosion is also electrochemical. In order to prevent oxidation, a preventative coating must interfere with the reaction.
At Aquadam, we ensure that there is a specialized coating on the inside of every tank. Therefore, the tanks are highly rust-resistant and you can rest easy knowing that the water will not damage your steel tank. The steel tanks have a long life polymer coating on the inside which not only protects from rusting but also prevents the growth of algae and bacteria on the tank walls.
Localized
Localized means that the corrosion only forms in a small part of the structure/metal. This usually happens because of the metal coming into contact with corrosion-causing stresses.
At Aquadam, we encourage our customers to install their steel tanks on a level concrete base (Although this is NOT a requirement). Therefore, the likelihood of your tank being exposed to corrosion-causing stresses are severely reduced.
Due to Caustic Agents
Caustic agents include any impure gas, liquid or solid that comes into contact with the metal. Some examples of caustic agents are Hydrogen sulfide and Sodium Hydroxide.
These agents can cause significant damage to steel tanks. However, at Aquadam, we have created tanks to withstand various chemicals. Therefore, you can use selected Aquadam tanks for chemical storage. A perfect example of this is our Fusion bonded epoxy tanks.
These tanks are made to withstand high pressures, fluctuating temperatures, and caustic agents. Perfect for any factory working with chemicals.
Tips on Preventing Corrosion in your Steel Tank
Now that we have discussed the various types of corrosion, we can look at all the ways you can ensure that you avoid it with your Steel Storage Tank.
It is important to note that these are general guidelines and every situation is unique. Therefore, we highly recommend that you speak to one of our sales representatives about exactly what you need, and they will advise on the best solution for you.
Area of Installation
While this is not a major factor, it should be taken into consideration. Placing the tank in an area where there will not be a lot of other elements present and in contact with the tank, is ideal.
As an example, placing the normal home tank, next to an area where you will constantly be working with caustic chemicals, can lead to some of the caustic elements to get into contact with the outside of the tank and cause corrosion.
Placement
Additionally, it would be ideal to place your steel tank on a concrete slab that will prevent dirt, organic materials, and other substances form gathering around the base of the tank’s exterior walls.
Tank’s Materials
It is important to note that not all steel tanks are identical. There are various materials and coatings that are placed on tanks to make them more suited for selected tasks than others.
As an example, at Aquadam we have various tanks with different coatings suited for certain applications. Lets briefly look at these tanks:
Zincalume Corrugated Tanks
Mainly made to store water and/or to be used as filtration tanks, sewage system tanks and treatment plants of water. These tanks are perfect for rainwater harvesting and storage of potable water.
Fire Protection Tanks
These tanks are fitted with the highest corrosion-resistance material available. it is called PosMAC.
These tanks can be used as emergency water storage in case of fires. Additionally, it can be used across the mining, industrial and agricultural sectors for storage and water treatment. A truly versatile steel water tank.
Rhino Tanks (Fusion Bonded Epoxy)
The Rhino tanks are made to be tougher than traditional steel. It consists of bolted steel plates that are coated with thermally bonded epoxy. Therefore, the tank has a much higher impact-durability.
The coating on this tank provides the most durable and resistant coating possible. It is the same as that used in chemical and industrial piping applications, and as such it is tougher than Zinc/Aluminum coatings and is exceptionally resilient to on-site damage.
The tank is used to store flammable liquids, selected chemicals, and water. However, it has, even more, uses for various industries, read more on this tank on our Rhino Tank Page.
Aquadam takes pride in working with the highest quality materials. We want to help you find the perfect tank. Contact our office to talk to a sales consultant that can help get you where you want to be,