Rust occurs when the metal structure is revealed to oxygen and moisture and can cost businesses money and affect productivity and can even be dangerous if not treated correctly. In one of the worst cases of corrosion from rust, an oil tanker named Erika in 1999 was carrying 10 billionsgallons of fuel oil and during a huge storm, 11 foot-deep cracks emerged in the deck of the boat and caused a huge spill. Rust has a cost to much smaller businesses too, and in this blog we will explain:
- How rust occurs
- What happens when a metal has rusted.
- What is rust made up from.
- Ways you can prevent rust.
Key Questions About Rust
Why does rusting happen?
Rust comes from iron oxide. When iron merges with oxygen in the air it begins to cause corrosion and affects the alloys and iron in the metal. The most common explanation to rusting is when it becomes exposed to water or damp environments. It begins quickly dissolving into microscopic gaps and this begins the corrosion process. Salt water increases the speed of rusting.
What happens when the metal is rusted?
When rusting occurs it expands the metal which causes more stress on the structure. It becomes weaker and more brittle as time passes. The rust will eventually corrode through each layer of the metal until it is completely rusted and this is when it is at its most vulnerable stage.
How do you prevent rust?
If metal is outside, its rusting time will be increased. Especially in humid/wet temperatures. Stainless steel and weathering steel seem to be the most common type of way to prevent rust. Alloys are less prone to rust and key ones include-
Stainless steel is made up of 11% chromium, this allows transformation so it can be used as a protective layer for chromium oxide, which basically shields the metal from rusting. If nickel is added to stainless steel as a component it can increase the protection of rusting.
Weathering Steel is made up of 21% of elements such as chromium, copper, nickel and phosphorous. The alloys which form from this decrease the corrosion rate – Weathering steel can be known as COR TEN and seems to be cheaper than stainless steel.
Factors To Consider To Help You Prevent Rust
There are a number of factors to consider when designing your metal structure. You need to make sure you can attach water drainage filters and a good air flow to prevent rust. Another helpful tip would be to weld your metal together and not use bolts, as this allows water and air into the structure. After you have finished building your structure you need to keep constant maintenance.
2. External Layer/Galvanisation
Applying the galvanisation process is some what cheaper than purchasing stainless steel. You need to apply an extra layer on the outside of the metal with a substance called metallic zinc. The zinc prevents elements of the metal from rusting and corroding – If rusting does begin to occurs, the zinc absorbs the rust in the the external coating.
Although the blurring technique is effective it is only a temporary option for smaller metal items. After the blurring process the metal looks smooth and gives a black-blue appearance – This is where it gets its name from. The processes is done through using steel parts, a mix of potassium nitrate, sodium hydroxide and water.
4. Oil/Organic Layers
Painting “organic” layers onto the material is another cheap way of preventing corrosion. The elements inside an organic coating will cause a barrier to prevent rusting elements. You can use oil protections as they are very good for keeping water and oil out. A normal coating is around 20mm thick.
5. Powdered layers
For this type of prevention you need to apply an even layer of dry powder onto the metal, then once heated it is turned into a thin solid layer of rust resistance. Types of dry powder include: acrylic, polyester, nylon and vinyl. This process is usually done through an electrostatic spray – it uses a non-charged powder and this charges the dried powder particles to attach to the surface. Once it has finished in a hot-oven it continues to stay a stronger barrier for rust.
Throughout all of these types of processes it is important to have regular maintenance checks to make sure that corrosion isn’t occurring, if rust does begin appearing it is best to use a sharp thin blade to remove it. After, you will reveal any grit and dirt which the rust has began creating, using a warm water and soap solution can clean this off. After doing these two checks, apply a coat of a rust resistance to the surface.
We hope you found this useful when thinking about how you can prevent rust. If you have any questions or comments, please as Tweet us we are always happy to connect!